ALBERT

Description: 〈p〉Publication date: Available online 8 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Journal of Operational Research〈/p〉 〈p〉Author(s): K.T. Huynh〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉We are interested in the stochastic modeling of a condition-based maintained system subject to continuous deterioration and maintenance actions such as inspection, partial repair and replacement. The partial repair is assumed dependent on the past in the sense that it cannot bring the system back into a deterioration state better than the one reached at the last repair. Such a past-dependency can affect (〈em〉i〈/em〉) the selection of a type of maintenance actions, (〈em〉ii〈/em〉) the maintenance duration, (〈em〉iii〈/em〉) the deterioration level after a maintenance, and (〈em〉iv〈/em〉) the restarting system deterioration behavior. In this paper, all these effects are jointly considered in an unifying condition-based maintenance model on the basis of restarting deterioration states randomly sampled from a probability distribution truncated by the deterioration levels just before a current repair and just after the last repair/replacement. Using results from the semi-regenerative theory, the long-run maintenance cost rate is analytically derived. Numerous sensitivity studies illustrate the impacts of past-dependent partial repairs on the economic performance of the considered condition-based maintained system.〈/p〉〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Ecological Economics, Volume 164〈/p〉 〈p〉Author(s): Jordi Teixidó, Stefano F. Verde, Francesco Nicolli〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This paper reviews the empirical literature analysing the effects of the EU Emissions Trading System (EU ETS) on low-carbon technological change. The emerging evidence is assessed, with references to both relevant economic concepts and the evolving regulation of the EU ETS through the years. The two most robust indications of the literature are: 〈em〉a)〈/em〉 free allocation (grandfathering) tended to hamper low-carbon investments in Phases I (2005–2007) and II (2008–2012), and 〈em〉b)〈/em〉 the EU ETS appears to have been relatively more effective in stimulating innovation of low-carbon technologies than their adoption. Importantly, however, a complete general picture of the impact of the EU ETS on low-carbon technological change is missing. The main gap regards the lack of empirical evidence for Phase III (2013−2020). Especially econometric studies are only few due to the lack of suitable databases accessible to researchers – a problem that the relevant public authorities are urged to address. Thanks to the recent reforms of the EU ETS, the incentives for innovation and adoption of low-carbon technologies are probably stronger today than ever before.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Ecological Economics, Volume 164〈/p〉 〈p〉Author(s): Rui Pedro Mota, Maria A. Cunha-e-Sá〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this paper we investigate the relationship between comprehensive measures of savings and changes in future consumption in OECD countries. This relationship is at the basis of the interpretation of adjusted net savings as a weak sustainability indicator, and so, evidence of its validity provides support to the use of this indicator. We construct various measures of comprehensive savings for 20 OECD countries to include depletion from non-renewable resources, human capital investment and technological progress. Given their importance, especially for rich countries, we focus on the role of technical progress and human capital, in the form of changes in education level. We do not find strong evidence in favor of including green adjustments in the conventional net savings. However, we find compelling evidence for the inclusion of technological progress. Since this involves a forward looking term, the above result suggests that to construct an indicator of weak sustainability from conventional net savings, some estimate of future technological progress is needed.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Geoforum, Volume 105〈/p〉 〈p〉Author(s): Arnab Roy Chowdhury, Kuntala Lahiri-Dutt〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Hirashasan is the term used for governance of diamond mining and trade – with a small bureaucracy and an exclusive set of rules and regulations – by the district administration of Panna in the state of Madhya Pradesh in India. Diamond mining in Panna encompasses diverse extractive practices that range from fully mechanised large-scale mining operations owned by the state, to small-scale and semi-mechanised mining carried out by farmers and landowners in groups, to individuals carrying out seasonal and part-time mining of diamonds in an artisanal manner. Based on an ethnographic study was undertaken from September 2016 to April 2017, we argue that Hirashasan has created an “extractive assemblage” that comprises four genres of mining and production systems: large-scale, small-scale, licensed artisanal and unlicensed artisanal. This assemblage is a product of historical, cultural and geographical contingencies as much as place-specificities, and does not lend itself to a single mode of governance. Mineral resource governance in a particular place, therefore, necessitates understanding and internalising the variegated and pluri-form extractive assemblages, such as that of the diamond economy in Panna.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 6 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Production Economics〈/p〉 〈p〉Author(s): W.W. Nasr, M.Y. Jaber〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Companies have to account for continuously evolving technologies that are driven by the consumer's appetite for new and innovative products, requiring them to modify their production systems to become flexible, where items do not have standard features and specifications. It is normal though that new products and processes would result in a considerable proportion of non-conforming items produced by the supplier and rejected by the buyer (a company). We consider a two-level joint production system that investigates the behavior of the supplier and the buyer's production systems. We assume that the proportion of non-conforming items produced by the supplier is a random variable whose mean and variance reduce due to learning effects. We examine investing in the supplier's process to speed up the learning process and propose a mathematical framework to quantify the effectiveness of an investment. Heuristics are developed to solve those mathematical models. We consider a finite planning horizon since products, today, have short lives, and we present a numerical study to show that the proposed action can be economically beneficial to the system.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 5 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Production Economics〈/p〉 〈p〉Author(s): Philipp Wetzel, Erik Hofmann〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this paper, we examine the functional form of the relationship between working capital assets and corporate performance beyond the traditional single-company perspective. In particular, we explore how a focal company's adequate level of working capital is influenced by the presence of limited financial resources along the supply chain. Moreover, we investigate the performance impact of supply chain finance (SCF)-oriented working capital management (WCM) approaches. Based on the SCF-oriented school of thought, we subject propositions regarding the relationship between working capital and corporate performance from prior WCM research to explorative empirical testing. In doing so, we raise awareness of factors that have yet to be tested. We derive methodological implications for conducting interorganizational studies in the field of SCF and outline a future research agenda. The explorative results indicate (i) the existence of a profit-maximizing level of working capital, (ii) superior performance of companies adopting an SCF-oriented WCM approach, (iii) higher profit-maximizing levels of working capital for focal companies facing financially constrained supply chain partners, (iv) a positive performance impact of efficient inventory management, and (v) differentiated payment strategies toward up- and downstream supply chain partners.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 5 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Journal of Operational Research〈/p〉 〈p〉Author(s): Shichen Zhang, Jianxiong Zhang〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Nowadays, some suppliers are looking for offline expansion in addition to their preexisting online channels relying on e-tailers. This study focuses on the e-tailer’s demand information sharing strategy with the supplier who may build upon brick-and-mortar stores. Both prevailing agreements between the supplier and the e-tailer are investigated: agency selling and reselling. The equilibrium results are quite different under these two agreements. Specifically, when the supplier’s offline entry cost is very small or large, the e-tailer shares information under agency selling while keeps information private under reselling. When the entry cost is intermediate, channel substitution rate is large and information uncertainty is small, the e-tailer withholds the demand information under agency selling while shares information under reselling to deter the supplier from entering an offline channel. Furthermore, two extensions about consumer behavior in multichannel selection are discussed: showrooming and webrooming. With showrooming or webrooming, the e-tailer’s information sharing decisions qualitatively hold, while with showrooming the drive factor behind may change; that is, withholding information under agency selling and sharing information under reselling may also serve as measures to encourage supplier offline entry when the effect of showrooming is strong.〈/p〉〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Geoforum, Volume 105〈/p〉 〈p〉Author(s): Eric Nost, Morgan Robertson, Rebecca Lave〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉We present results from a Q-method survey on a key question in water governance and reflect on Q-method as an approach that quantitatively distinguishes qualitative subject-positions. The survey was conducted with the Q-TIP platform, which we designed for the study and is now open to all researchers (〈a href="https://qtip.geography.wisc.edu/" target="_blank"〉https://qtip.geography.wisc.edu/〈/a〉). Our study asked how stream restoration should be evaluated in state regulatory programs. Streams are dynamic and multi-scalar geomorphological, chemical, biological, as well as socio-cultural systems and it is not obvious what good restoration means or how it should be assessed. Across the stream restoration community we found four different priorities, each of which differently characterizes the feasibility of assessing outcomes. These four perspectives were that metrics of success should: (a) be rigorous and site-focused; (b) be simple and easy to implement in the field; (c) capture complexity; (d) reflect innovations in watershed planning, ecosystem functions, and stakeholder inclusion. These subject-positions on assessment do not, however, map cleanly onto informant profession or background, and a single informant can hold more than one view. Despite relatively limited uptake in geography, Q offers the promise of a critical quantitative approach to researching subjectivity in a way that is compatible with poststructural understandings of identity. We use our case material to show that methodological rules of thumb limit Q’s potential, but we demonstrate unconventional approaches. Drawing on the process and results of our survey of stream restoration practitioners, we argue that Q-method can help in the task of representing subjectivity while respecting its complexity.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 2 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Journal of Operational Research〈/p〉 〈p〉Author(s): Kieran Conboy, Patrick Mikalef, Denis Dennehy, John Krogstie〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉While the topic of analytics is rapidly growing in popularity across various domains, there is still a relatively low amount of empirical work in the field of operations research (OR). While studies of various technical and business aspects of analytics are emerging in OR, little has been done to address how the OR community can leverage business analytics in dynamic and uncertain environments – the very place where OR is supposed to play a key role. To address this gap, this study draws on the dynamic capabilities view of the firm and builds on eight selected case studies of operations research activity in large organisations, each of which have invested significantly in analytics technology and implementation. The study identifies fourteen analytics-enabled micro-foundations of dynamic capabilities, essentially highlighting how organisations can use analytics to manage and enhance their OR activities in dynamic and uncertain environments. This study also identifies six key cross-cutting propositions emerging from the data and develops a roadmap for future OR researchers to address these issues and improve the use and value of analytics as enablers of organisational dynamic capabilities.〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Journal of Operational Research, Volume 279, Issue 2〈/p〉 〈p〉Author(s): 〈/p〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Ecological Economics, Volume 164〈/p〉 〈p〉Author(s): Leah Temper, Dylan McGarry, Lena Weber〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The role of science and knowledge production is at a crossroads, as societal transformation calls for challenging dominant forms of knowledge production that have contributed to marginalizing other ways of knowing. This presents a challenge to mainstream science and invites a deeper reflection on our roles as scientists and exploration of alternative engaged, post-normal and activist approaches to research. This paper examines the diverse ways researchers are meeting this challenge. Employing the device of the Tarot deck we describe seven “characters” to illustrate the variety of roles and approaches that trans-disciplinary, transformative, transgressive and activist researchers are engaging in. These characters are used to introduce and develop the concept of political rigour as a means of expanded academic rigour in new emancipatory scientific paradigms. We demonstrate how these Tarot characters can be used as an activity for collective and personal reflexivity and propose ten principles that frequently emerge in a ‘political’ peer review process. We argue that the insights emerging from these strands of radical, critical, engaged and applied forms of scholarship, can significantly improve the understanding of what a “transformative knowledge paradigm” may look like in practice and how it can be mobilized for social change and environmental justice.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Ecological Economics, Volume 164〈/p〉 〈p〉Author(s): Pasi Heikkurinen, Toni Ruuska, Kristoffer Wilén, Marko Ulvila〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This article aims to reconcile tensions around ‘the Anthropocene’ by reviewing and integrating the discourses on the new geological epoch. It is argued that the Anthropocene discourses based on natural and social sciences are complementary. The anthropogenic epoch detrimental to the Earth's biodiversity, however, does not reduce to any discourse. Instead of calling to reject discourses that do not accept this limitation of language or alternatively do not show sensitivity to contextual matters, the article demonstrates how different Anthropocene discourses can be combined. The study concludes that in order to exit the epoch, anthropocentric discourses on the Anthropocene remain ineffective unless complemented by non-anthropocentric discourses.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Geoforum, Volume 105〈/p〉 〈p〉Author(s): Renee Tapp〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Growing tax credit markets to preserve historic structures, deliver affordable housing, and encourage investment in distressed communities reveal intensification in the financialization of real estate. This paper develops a case study of federal historic tax credits to argue that there are multiple and interrelated processes of financialization at work within a single building, including tax sheltering. Drawing on commodification and marketization literatures in critical human geography, this paper illustrates how the fracturing of property rights by the tax code refashions buildings into ‘bundled’ financial assets. It uses qualitative and quantitative data collected in 2016–2017 to (i) demonstrate the production of new inventories of historic buildings through the revaluation of old structures, (ii) examine overlapping geographies of tax and finance produced by the strategic alignment of state and federal tax law, and (iii) discuss the creation of secondary credit markets by financial investors through the unbundling of the capital stack. Although historic tax credits—and tax credits in general—are now an integral part of real estate financing, the market for tax credits provides valuable theoretical insights into the variations of urban financialization that co-exist in the same physical space.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Transportation Research Part E: Logistics and Transportation Review, Volume 129〈/p〉 〈p〉Author(s): Christopher S. Tang, Lucas P. Veelenturf〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉By leveraging new technologies (Additive Manufacturing, Advanced Robotics, Artificial Intelligence, Autonomous Vehicles, Blockchain, Drones, Internet of Things, etc.), many companies are developing cyber-physical systems that can change the competition landscape. In the midst of this exciting development, we examine the strategic role of logistics and transportation services for creating economic, environmental and social values. Also, we discuss some new research directions.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Transportation Research Part E: Logistics and Transportation Review, Volume 129〈/p〉 〈p〉Author(s): Tsan-Ming Choi〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Operations management (OM) is an important area in business and engineering, which can be regarded as a spinoff of Operations Research and Management Science (OR/MS). In Web of Science, 〈em〉Transportation Research – Part E: Logistics and Transportation Review〈/em〉 (TRE) is listed in the category of OR/MS. In fact, according to statistics and our editorial experience, about half of the papers submitted to TRE are classified as OM papers. Owing to the popularity of OM papers in TRE, this paper updates the editorial policy of TRE in the area of OM and highlights some points to help authors to successfully publish high quality and impactful papers in TRE.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Transportation Research Part E: Logistics and Transportation Review, Volume 128〈/p〉 〈p〉Author(s): Zhixiang Chen, Bopaya Bidanda〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Based on two sustainable manufacturing strategies: resource recycling and emission reduction, this paper addresses a new production-inventory problem of multiple factories with JIT logistics, component recovery and emission control. Motivated by beer industry, we formulate this problem based on two decision mechanisms: (1) PI-CR decision mechanism–sole consideration of component recovery (component recycling) (2) PI-RE decision mechanism–joint consideration of component recycling and emission control. In the PI-RE decision mechanism, two emission control policies—carbon tax and carbon cap & trade are implemented. Numerical analysis is demonstrated to show the application of the models, and the managerial implications are put forward. Results show that emission control and resource recycling strategies have different impacts on the decision, increasing the return rate of recoverable component is an effective approach to currently reduce emissions and cost, while the cap & trade policy is more effect than the carbon tax policy in controlling emissions.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Computers & Operations Research, Volume 111〈/p〉 〈p〉Author(s): Omar Foutlane, Issmail El Hallaoui, Pierre Hansen〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The integral simplex using decomposition (ISUD) is a primal algorithm dedicated to solve set partitioning problems (SPP). Given an integer solution, the integral simplex using decomposition (ISUD) seeks a descent direction that leads to an improved adjacent integer solution. It uses a horizontal decomposition (of a linear transformation of the constraint matrix). We propose the integral simplex using double decomposition (ISU2D) which is a parallel version of ISUD. It uses an innovative disjoint vertical decomposition to find in parallel orthogonal descent directions leading to an integer solution with a larger improvement. Each descent direction identifies a set of variables that will leave the current solution and a set of entering variables with better costs. To find these directions, we develop a dynamic decomposition approach that splits the original problem into subproblems that are then solved in parallel by ISUD. Our main innovation is the use of the current solution as a foundation for the construction of the set of subproblems; the set changes during the optimization process as the current solution changes. In addition, we use bounding and pricing strategies and implement parallel processing techniques. We show that ISU2D is 3 to 4 times faster than ISUD on large instances.〈/p〉〈/div〉

Description: 〈p〉Publication date: September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy Economics, Volume 83〈/p〉 〈p〉Author(s): Alex O. Acheampong〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The need to formulate policies to mitigate global warming has necessitated the need to understand the drivers of carbon emissions. The current study utilises the system-generalised method of moments to investigate the direct and indirect effect of financial development on carbon emissions for 46 sub-Saharan Africa countries over the period 2000–2015. Using several indicators of financial development, the empirical results reveal that financial development measured using broad money, domestic credit to the private sector and domestic credit to private sector by banks increase carbon emissions while FDI, liquid liabilities and domestic credit to private sector by financial sector do not affect carbon emissions. The results show that none of the financial development indicators exerts a significant nonlinear effect on carbon emissions. The results further indicate that FDI moderates economic growth to reduce carbon emissions but does not moderate energy consumption to affect carbon emissions. Contrarily, financial development measured using broad money, domestic credit to private sector by banks, domestic credit to private sector by financial sector and domestic credit to private sector moderate energy consumption to increase carbon emissions while the first three indicators of financial development moderate economic growth to increase carbon emissions. The results do not confirm the existence of the EKC hypothesis but confirm that population size, energy consumption, trade openness, urbanisation and economic growth increase carbon emissions. There are some variations in these results across regional and income groupings. These findings do advance not only knowledge but also have several implications for sustainable development policy.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Ecological Economics, Volume 164〈/p〉 〈p〉Author(s): Marco d'Errico, Marco Letta, Pierluigi Montalbano, Rebecca Pietrelli〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The existence of thresholds constitutes an important frontier topic for resilience analysis and measurement. This paper contributes to the literature by identifying critical resilience thresholds below which rural Tanzanian households are unable to absorb the negative effects of temperature anomalies on long-run growth. To make up for the lack of long micro panels, we generate a synthetic panel covering the time span 2000–2013. We show that 25%–47% of households in our sample lie below the estimated thresholds. The evidence of resilience-driven regime shifts and non-linear dynamics has important implications for adaptation to climate change in developing countries and is of significant interest for policy interventions.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Geoforum, Volume 106〈/p〉 〈p〉Author(s): Gemma Sou, Ruth Webber〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉There are many strategies and models that attempt to measure the impacts and losses from environmental crises. However, there remains a conceptual and methodological bias as assessments provide estimates of tangible and quantifiable indicators, whilst impact to intangible resources that are not easily quantifiable remain a significant oversight in disaster studies more specifically, and sustainability research more broadly. In this paper we use in-depth longitudinal qualitative data to theoretically and empirically demonstrate how intangible resources shape people’s experience of so-called “natural” disasters. Building on this, we critically unpack how intangible resources facilitate household disaster recovery. We focus on home – an intangible resource – in order to explore these issues. The case study in Puerto Rico shows that the social characteristics of home are challenged, transformed, and/or exacerbated in different ways, and at different times, in post-disaster contexts. Our longitudinal approach reveals how people’s feelings of belonging and attachment, alienation and detachment from home, fluctuate over time. In this way, the paper sheds light on how intangible resources are experienced temporally and spatially. The paper also reveals that the performance of actors such as the State and Non-governmental organisations significantly shape how intangible resources such as home are transformed, and households’ agency to maintain and recover such intangibles in post-disaster contexts. The analysis directly challenges the skewed and reductive hierarchies of what counts as a disaster loss. This is an innately political endeavour because it aims to develop strategic decision-making, from preparedness to recovery, that is sustainable for affected populations.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 29 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Long Range Planning〈/p〉 〈p〉Author(s): Eshani Beddewela〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Addressing calls to explore how subsidiaries of MNCs operating in different institutional contexts resolve institutional duality, this paper brings together dual theoretical explanations from legitimacy and neo-institutional theory, to examine how decision-making for corporate community responsibility (CCR) occurs across ten subsidiaries operating in Sri Lanka. Using qualitative data, it shows that while subsidiaries’ implementation of local CCR conform to that of their parents at an aggregate level, those subsidiaries encountering higher levels of institutional conflict in the host-country, are sanctioned by their parent companies to de-couple their local CCR projects. These findings raise interesting questions about the dynamism in subsidiary responses to resolving institutional duality relevant for future scholarly research.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Omega, Volume 89〈/p〉 〈p〉Author(s): 〈/p〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Transportation Research Part B: Methodological, Volume 128〈/p〉 〈p〉Author(s): Xiaotian Wang, Xin Wang〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Reservation-based parking systems have the merit of eliminating vehicle cruising for parking. While many long-period (e.g., daily) parking reservation services are already in use, short-period (e.g., hourly) parking reservation remains a huge challenge due to the high uncertainty of customer arrivals and departures. To mitigate the service failure caused by random late departures of customers, we propose a new flexible reservation mechanism in which the reservation is no longer restricted to a specific location at a specific time, but tolerates predetermined spatiotemporal flexibility instead. With a pricing instrument designed for such parking flexibility, customers can coordinate to significantly reduce the reservation failure rate, resulting in an optimal system equilibrium benefiting the entire society. Due to the complex nature of this system, a continuum approximation framework is used to provide tractable analysis for a large-scale urban parking system. We can successfully provide accurate system management decision support with a bounded optimality gap and analytical insights.〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 30 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Computers & Operations Research〈/p〉 〈p〉Author(s): Lucas Kletzander, Nysret Musliu〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉In many professions the demand for work requires employees to work in different shifts to cover varying requirements including areas like health care, protection services, transportation, manufacturing or call centers. However, there are many constraints that need to be satisfied in order to create feasible schedules. The demands can be specified in various ways, different legal requirements need to be respected and employee satisfaction has to be taken into account. Therefore, automated solutions are mandatory to stay competitive. However, even then it is often hard to provide good solutions in reasonable time as many of the problems are NP-hard.〈/p〉 〈p〉While not each problem will require the whole set of available restrictions, it is cumbersome to develop a new specification format and corresponding solver for each problem. Often these can not be well applied to similar problems differing in some requirements. On the other hand it is a challenging task to provide a general formulation and solution methods that can solve large integrated problems, as even several sub-problems on their own are known to be NP-hard.〈/p〉 〈p〉Therefore a new framework is proposed for the general employee scheduling problem that allows the implementation of various heuristic algorithms and their application to a wide range of problems. This is realized by proposing a unified handling of constraints and the possibility to implement various moves that can be reused across different algorithms. Further, a new search method is developed and implemented in the framework.〈/p〉 〈p〉In order to show the applicability to a wide range of problems, we take different problems from literature that cover different types of demand and constraints, translate their instances to our formulation and apply our solver to those instances as well as our own instances with good results. For one problem class our framework could obtain better solutions for several benchmark instances.〈/p〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Transportation Research Part B: Methodological, Volume 128〈/p〉 〈p〉Author(s): Li Li, Saif Eddin Jabari〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉Decentralized intersection control techniques have received recent attention in the literature as means to overcome scalability issues associated with network-wide intersection control. Chief among these techniques are backpressure (BP) control algorithms, which were originally developed of for large wireless networks. In addition to being light-weight computationally, they come with guarantees of performance at the network level, specifically in terms of network-wide stability. The dynamics in backpressure control are represented using networks of point queues and this also applies to all of the applications to traffic control. As such, BP in traffic fail to capture the spatial distribution of vehicles along the intersection links and, consequently, spill-back dynamics.〈/p〉 〈p〉This paper derives a position weighted backpressure (PWBP) control policy for network traffic applying continuum modeling principles of traffic dynamics and thus capture the spatial distribution of vehicles along network roads and spill-back dynamics. PWBP inherits the computational advantages of traditional BP. To prove stability of PWBP, (i) a Lyapunov functional that captures the spatial distribution of vehicles is developed; (ii) the capacity region of the network is formally defined in the context of macroscopic network traffic; and (iii) it is proved, when exogenous arrival rates are within the capacity region, that PWBP control is network stabilizing. We conduct comparisons against a real-world adaptive control implementation for an isolated intersection. Comparisons are also performed against other BP approaches in addition to optimized fixed timing control at the network level. These experiments demonstrate the superiority of PWBP over the other control policies in terms of capacity region, network-wide delay, congestion propagation speed, recoverability from heavy congestion (outside of the capacity region), and response to incidents.〈/p〉 〈/div〉

Description: 〈p〉Publication date: Available online 29 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Production Economics〈/p〉 〈p〉Author(s): Tsan-Ming Choi, Lipan Feng, Rong Li〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In platform operations for rental services, product information disclosure (supported by the blockchain technology) is critical to attract customers. By building a stylized duopoly basic analytical model, we conduct a game-theoretic analysis to explore the product information disclosure game between two rental service platforms. We derive the optimal level of product information disclosure and identify the theoretical conditions in which it is optimal to disclose or not to disclose information, which actually means two different types of supply chains. Under the basic model with the two competing platforms scenario, we uncover that from each platform's perspective, there exists a critical threshold on the proportion of information sensitive consumers in the market with which the platform can decide whether it is optimal to disclose product information or not. If the information auditing cost is sufficiently small, it is optimal for the platform to disclose the product information as much as possible. We find that when the product's rental service profit margin increases, the likelihood that both competing platforms will disclose information (including full information) for their products is higher. We also explore the impacts brought by product information disclosure on consumer surplus and seller benefits, and discuss the roles played by the blockchain technology. To check robustness of the results as well as to examine different supply chain configurations, we extend the analysis to the cases when (i) the platforms are risk averse in decision making, (ii) rather than selling the product, the seller (owner of the product to be shared) consigns the product to the platform and shares a revenue, (iii) there is a common rental service platform which receives and provides rental services for two substitutable products. We find that the core qualitative managerial insights remain valid in the basic and all the extended models. Managerial implications are discussed.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 29 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Journal of Operational Research〈/p〉 〈p〉Author(s): Claudio Arbib, Mustafa Ç. Pınar, Matteo Tonelli〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉Consider a three-level non-capacitated location/pricing problem: a firm first decides which facilities to open, out of a finite set of candidate sites, and sets service prices with the aim of revenue maximization; then a second firm makes the same decisions after checking competing offers; finally, customers make individual decisions trying to minimize costs that include both purchase and transportation. A restricted two-level problem can be defined to model an optimal reaction of the second firm to known decision of the first.〈/p〉 〈p〉For non-metric costs, the two-level problem corresponds to 〈span〉Envy-free Pricing〈/span〉 or to a special 〈span〉Network Pricing〈/span〉 problem, and is 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si65.svg"〉〈mi mathvariant="bold-script"〉APX〈/mi〉〈/math〉-complete even if facilities can be opened at no fixed cost. Our focus is on the metric 1-dimensional case, a model where customers are distributed on a main communication road and transportation cost is proportional to distance. We describe polynomial-time algorithms that solve two- and three-level problems with opening costs and single 1〈sup〉〈em〉st〈/em〉〈/sup〉 level facility. Quite surprisingly, however, even the two-level problem with no opening costs becomes 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si66.svg"〉〈mi mathvariant="bold-script"〉NP〈/mi〉〈/math〉-hard when two 1〈sup〉〈em〉st〈/em〉〈/sup〉 level facilities are considered.〈/p〉 〈/div〉

Description: 〈p〉Publication date: Available online 29 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Production Economics〈/p〉 〈p〉Author(s): Kimitoshi Sato, Kenichi Nakashima〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In recent years, pay-per-use (PPU) services have been introduced that involve metered billing based on data collected from sensor devices. Although such a PPU service provides benefits to customers who are not planning to use the product frequently, the company is exposed to uncertainty regarding the amount of revenue that will be generated. This study examines the conditions under which a PPU service will be effective at increasing a firm's profit in the presence of uncertainty regarding customers' expected and actual usage frequencies. We consider two pricing problems. First, we formulate a single-period model for when the selling price of the product is given and derive an optimal PPU fee to maximize the expected profit. Then, we analytically show that the PPU service has higher profits than the case without the service when the actual usage is higher than the expected usage. Second, we formulate a joint pricing model in which the firm determines jointly the PPU fee and the selling price to maximize the expected profit. Then, we numerically show that the firm benefits from the PPU service when both the customers' valuation and the actual usage are high.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 29 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Journal of Operational Research〈/p〉 〈p〉Author(s): Zachary Feinstein〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉We construct a continuous time model for price-mediated contagion precipitated by a common exogenous stress to the banking book of all firms in the financial system. In this setting, firms are constrained so as to satisfy a risk-weight based capital ratio requirement. We use this model to find analytical bounds on the risk-weights for assets as a function of the market liquidity. Under these appropriate risk-weights, we find existence and uniqueness for the joint system of firm behavior and the asset prices. We further consider an analytical bound on the firm liquidations, which allows us to construct exact formulas for stress testing the financial system with deterministic or random stresses. Numerical case studies are provided to demonstrate various implications of this model and analytical bounds.〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 29 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Human Resource Management Review〈/p〉 〈p〉Author(s): Sean Edmund Rogers, Carliss D. Miller, Carol Flinchbaugh, Mark Giddarie, Brian Barker〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This manuscript theorizes difference in the work structure of paid and unpaid internships and its influence on intern job satisfaction and vocational development. Specifically, we draw upon theories from human resource management and volunteerism to argue why unpaid internships might exhibit less job structure than paid internships, and how this possibly influences the experiences of interns. As internships continue to be performed by a mix of paid and unpaid workers and as the proportion of unpaid interns steadily increases, it becomes ever important to understand how mainstream workplace concepts such as job design apply to workers who do not receive monetary compensation for their labor. We offer several testable propositions concerning unpaid interns and discuss implications for theory and practice.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 29 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Journal of Operational Research〈/p〉 〈p〉Author(s): Bo Jin〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In a recent paper, Galle, Barnhart, and Jaillet [Galle, V., Barnhart, C., & Jaillet, P. (2018). A new binary formulation of the restricted container relocation problem based on a binary encoding of configurations. 〈em〉European Journal of Operational Research, 267〈/em〉(2), 467–477] introduced a new variant of the container relocation problem (CRP), named the relaxed restricted CRP, where every container can be relocated at most once for retrieving each target container. The authors also proposed a binary integer programming model for formulating the relaxed restricted CRP. In this paper, it is first shown that the proposed model contains two deficiencies in formulating the “last in, first out” (LIFO) policy. These deficiencies will cause the solutions obtained by the model to correspond to infeasible configurations or infeasible relocation sequences. Then, the LIFO policy is analyzed in detail and reformulated as linear constraints correctly. Lastly, the corrected integer programming formulation is presented. Computational experiments show that the corrected model dramatically reduces complexity and improves performance.〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 29 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Computers & Operations Research〈/p〉 〈p〉Author(s): Cheng-Hung Wu, Yi-Chun Yao, Stéphane Dauzère-Pérès, Cheng-Juei Yu〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A dynamic decision model that coordinates dispatching and preventive maintenance decisions for failure-prone parallel machines in make-to-order (MTO) production environments is developed in this research. The primary objective is to minimize the weighted long-run average waiting costs of MTO systems. Two common but seldom studied stochastic factors, namely, the dispatching-dependent deterioration of machines and machine-health-dependent production rates, are explicitly modeled in the proposed dynamic dispatching and preventive maintenance (DDPM) model. Although the DDPM model is developed using Markov decision processes, it is equally effective in non-Markovian production environments. The performance of the DDPM model is validated in Markovian and non-Markovian production environments. Compared with several methods from the literature, simulation results show an improvement of at least 45.2% in average job waiting times and a minimum reduction of 48.9% in average machine downtimes. The comparison results between the optimal dynamic dispatching policies with and without coordinated preventive maintenance show that performance improvement can be mostly attributed to the coordination between preventive maintenance and dispatching decisions.〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 28 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Omega〈/p〉 〈p〉Author(s): Fouad EL Ouardighi, Jeong Eun Sim, Bowon Kim〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This research investigates the impact of both horizontal and vertical competition, on the one hand, and strategy types (commitment-based 〈em〉versus〈/em〉 contingent-based equilibrium strategies), on the other hand, on the pollution accumulated by two supply chains over time. We consider a two-stage game model where two manufacturers and two retailers are involved in a wholesale price contract, in order to supply the demand over a finite time horizon. In the first stage of the game, the manufacturers set their respective optimal transfer prices. During the second stage, polluting emissions are created over time in proportion with demand, which is controlled by the retailers’ respective consumer prices. In this stage, the manufacturers are involved in emissions abatement. In this setup, we seek to identify the combination of market structure and strategy type that leads the two supply chains to generate the lowest pollution intensity and the highest level of abatement intensity.〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 29 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Computers & Operations Research〈/p〉 〈p〉Author(s): Janniele A.S. Araujo, Haroldo G. Santos, Bernard Gendron, Sanjay Dominik Jena, Samuel S. Brito, Danilo S. Souza〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Resource Constrained Project Scheduling Problems (RCPSPs) without preemption are well-known 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si2.svg"〉〈mrow〉〈mi mathvariant="bold-script"〉N〈/mi〉〈mi mathvariant="bold-script"〉P〈/mi〉〈/mrow〉〈/math〉-hard combinatorial optimization problems. A feasible RCPSP solution consists of a time-ordered schedule of jobs with corresponding execution modes, respecting precedence and resources constraints. In this paper, we propose a cutting plane algorithm to separate five different cut families, as well as a new preprocessing routine to strengthen resource-related constraints. New lifted versions of the well-known precedence and cover inequalities are employed. At each iteration, a dense conflict graph is built considering feasibility and optimality conditions to separate cliques, odd-holes and strengthened Chvátal-Gomory cuts. The proposed strategies considerably improve the linear relaxation bounds, allowing a state-of-the-art mixed-integer linear programming solver to find provably optimal solutions for 754 previously open instances of different variants of the RCPSPs, which was not possible using the original linear programming formulations.〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 28 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Journal of Operational Research〈/p〉 〈p〉Author(s): Mike G. Tsionas〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Mitropoulos et al. (Mitropoulos P., M. A. Talias, and I. Mitropoulos, 2015, Combining stochastic DEA with Bayesian analysis to obtain statistical properties of the efficiency scores: An application to Greek public hospitals. European Journal of Operational Research 243, 302-311) suggested the use of a Bayesian approach in Data Envelopment Analysis (DEA) which can be used to obtain posterior distributions of efficiency scores. In this paper, we avoid their assumption that alternative data sets are simulated from the predictive distribution obtained from their simple data generating process of a normal distribution for the data. The new approach has two significant advantages. First, the posterior proposed in this paper is coherent or principled in the sense that it is consistent with the DEA formulation. Second, and perhaps surprisingly, it is not necessary to solve linear programming problems for each observation in the sample. Bayesian inference is organized around Markov Chain Monte Carlo techniques that can be implemented quite easily. We conduct extensive Monte Carlo experiments to investigate the finite-sample properties of the new approach. We also provide an application to a large U.S banking data set. The sample is an unbalanced panel of US banks with 2,397 bank–year observations for 285 banks. The main purpose of the analysis is to compare distributions of efficiency scores. Relative to DEA, Bayes DEA provides different efficiency scores and their sample distribution has significantly less probability concentration around unity. The comparison with bootstrap-DEA shows that results from Bayes DEA are in broad agreement.〈/p〉〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Ecological Economics, Volume 164〈/p〉 〈p〉Author(s): Ing-Marie Gren, Frederic Ang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In a stacking system abatement measures with simultaneous effects on climate and water targets, such as wetland construction and cultivation of energy crops, are credited for the abatement of multiple pollutants. In this study we calculated and compared the abatement costs of achieving multiple environmental targets with and without stacking under different policy regimes (emissions trading, charge, standards). To this end, a static mixed integer programming model was constructed. Theoretical analysis showed that, irrespective of policy regime, the cost of achieving predetermined emission targets is always lower when stacking is allowed. Another result was the excess abatement of pollutant under a no stacking system. Application to the Baltic Sea region showed that cost savings from stacking of pollutant abatement vary between policy regimes, being smallest for price regulation and highest for emission standards. However, the gains from stacking were unevenly distributed among the nine countries surrounding the Baltic Sea under all policy regimes, with Poland making the largest gain and Estonia, Russia and Latvia facing losses. Excess abatement without stacking in relation to the target was highest for nitrogen under all policy regimes, comprising up to 52% of the target abatement.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Transportation Research Part B: Methodological, Volume 128〈/p〉 〈p〉Author(s): Jian Wang, Siyuan Gong, Srinivas Peeta, Lili Lu〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Recently, model predictive control (MPC)-based platooning strategies have been developed for connected and autonomous vehicles (CAVs) to enhance traffic performance by enabling cooperation among vehicles in the platoon. However, they are not deployable in practice as they require the embedded optimal control problem to be solved instantaneously, with platoon size and prediction horizon duration compounding the intractability. Ignoring the computational requirements leads to control delays that can deteriorate platoon performance and cause collisions between vehicles. To address this critical gap, this study first proposes an idealized MPC-based cooperative control strategy for CAV platooning based on the strong assumption that the problem can be solved instantaneously. It also proposes a solution algorithm for the embedded optimal control problem to maximize platoon performance. It then develops two approaches to deploy the idealized strategy, labeled the deployable MPC (DMPC) and the DMPC with first-order approximation (DMPC-FOA). The DMPC approach reserves certain amount of time before each sampling time instant to estimate the optimal control decisions. Thereby, the estimated optimal control decisions can be executed by all the following vehicles at each sampling time instant to control their behavior. However, under the DMPC approach, the estimated optimal control decisions may deviate significantly from those of the idealized MPC strategy due to prediction error of the leading vehicle's state at the sampling time instant. The DMPC-FOA approach can significantly improve the estimation performance of the DMPC approach by capturing the impacts of the prediction error of the leading vehicle's state on the optimal control decisions. An analytical method is derived for the sensitivity analysis of the optimal control decisions. Further, stability analysis is performed for the idealized MPC strategy, and a sufficient condition is derived to ensure its asymptotic stability under certain conditions. Numerical experiments illustrate that the control decisions estimated by the DMPC-FOA approach are very close to those of the idealized MPC strategy under different traffic flow scenarios. Hence, DMPC-FOA can address the issue of control delay of the idealized MPC strategy effectively and can efficiently coordinate car-following behaviors of all CAVs in the platoon to dampen traffic oscillations. Thereby, it can be applied for real-time cooperative control of a CAV platoon.〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 21 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Human Resource Management Review〈/p〉 〈p〉Author(s): Grace Chun Guo, Luciana Turchick Hakak, Akram Al Ariss〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Although international migrant employees have been recognized as an integral part of the global workforce contributing to the competitive advantages of the host countries and organizations, research has demonstrated that they face unequal treatment and remain a vulnerable group in the workplace due to their foreign national origin. In this paper, we focus on an understudied ascribed characteristic—foreign national origin and inequality associated with this characteristic toward international migrant employees. Drawing on theories of ascriptive inequality and the institutional logics perspective, we propose a multi-level theoretical model that illustrates how institutional logics at the macro-, meso-, and micro-level, allow inequality due to foreign national origin to be produced, increased, or mitigated. Our theoretical model also explicates the cross-level effects of institutional logics on inequality toward international migrant employees. Lastly, our theorization explores how inequality due to foreign national origin can be questioned and tackled. Implications for theory, practice, and policy are discussed.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 21 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Computers & Operations Research〈/p〉 〈p〉Author(s): Carl Axel Folkestad, Nora Hansen, Kjetil Fagerholt, Henrik Andersson, Giovanni Pantuso〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Carsharing has received increased attention from the Operations Research community in recent years. Currently, many systems are adopting electric vehicles that require charging when battery levels fall below a given level. To do this, staff is often used to move cars to charging stations. Repositioning cars, rather than simply moving them to the closest charging station, might provide a better distribution of cars and in turn generate increased revenue and customer service while only marginally increase the operational costs. We present a mathematical model for the problem of charging and repositioning a fleet of shared electric cars. The model considers the assignment of cars to charging stations and the routing of staff and service vehicles. The complexity of the resulting mixed integer program makes it impossible to solve real world instances using a commercial solver. Therefore, we propose a new Hybrid Genetic Search with Adaptive Diversity Control algorithm. Tests based on data from a real life carsharing organization demonstrate that the proposed method can handle real size instances and that combining repositioning and charging operations can give significant benefits.〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 21 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Journal of Operational Research〈/p〉 〈p〉Author(s): Zelin Zhang, Minghui Ma, Peter T.L. Popkowski Leszczyc, Hejun Zhuang〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉This research proposes an analytical model of the joint optimization of coupon face value and duration together with the product price, and determines the impact of coupon design on consumers’ redemption behavior. A model of rational forward-looking consumers’ redemption behavior is derived that incorporates forgetting (to redeem) and stochastic redemption costs.〈/p〉 〈p〉Results show that when product price is exogenous, long-duration coupons may result in increased seller profits and always increase consumer surplus. Moreover, a one-period coupon is never optimal when (1) the difference in valuations for high-value (loyal) and low-value (non-loyal) consumers or (2) the coupon face value is larger than the redemption costs of high-value consumers. Long-duration coupons tend to be optimal when the level of recall of high-value consumers is sufficiently low, which reduces redemption by high-value consumers.〈/p〉 〈p〉Coupon duration together with face value plays an important role in coupons’ ability to price discriminate between different consumer segments and to avoid head-on competition with other sellers. Results can replicate empirically observed redemptions patterns, which has important implications for the strategic targeting of coupons to different consumer segments.〈/p〉 〈p〉A coupon may result in an increase or decrease in price. When the difference in valuation between high-value and low-value consumers is high (relative to the redemption costs), a seller can either reduce price and lower face value or increase coupon duration for the purpose of avoiding redemption by high-value consumers.〈/p〉 〈/div〉

Description: 〈p〉Publication date: Available online 22 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Computers & Operations Research〈/p〉 〈p〉Author(s): Eduardo A.J. Anacleto, Cláudio N. Meneses, Santiago V. Ravelo〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The Unconstrained Binary Quadratic Programming problem (〈code〉UBQP〈/code〉) belongs to the NP-hard class and has become a framework for modeling a variety of combinatorial optimization problems. The methods most commonly used to solve instances of the 〈code〉UBQP〈/code〉 explore the concept of neighborhood of a solution. Given a binary vector 〈em〉x〈/em〉 ∈ {0, 1}〈sup〉〈em〉n〈/em〉〈/sup〉, solution to a 〈code〉UBQP〈/code〉 instance, a neighborhood of 〈em〉x〈/em〉 can be defined by flip moves. 〈em〉Flip moves〈/em〉 consist on selecting one or more elements (positions) of 〈em〉x〈/em〉 and “flip” their values to their complementary values (i.e., from 1 to 0 or from 0 to 1). Normally, those methods compute a large number of flip moves, and so the whole process to solve an instance can be quite time consuming. In order to reduce this time, some works have proposed ways to efficiently evaluate one or two flip moves, and also extensions to higher order moves. In this paper we propose two closed-form formulas for evaluating quickly any order of flip moves. To test our theoretical findings, we executed an extensive set of computational experiments over well-known instances for the problem. Against common belief, our results show that it is possible to compute high order flip moves very fast.〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 21 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Human Resource Management Review〈/p〉 〈p〉Author(s): Kibum Kwon, Taesung Kim〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The purpose of the current literature review is to (a) provide a comprehensive understanding of the relationship between employee engagement and innovative behavior through the lens of the JD-R model; (b) identify and revisit the guiding theories underpinning employee engagement studies; and (c) construct an integrated conceptual framework based on empirically validated factors and their relationships, along with relevant theories. An integrative literature review of 34 empirical studies indicates that employees perceive a mix of reasonably high demands and high resources to be ideal for their engagement, innovative behavior is a consequence of these delicate interactions, and engaged employees are more likely to behave innovatively by activating coping strategies to deal with challenges. Together, these findings suggest an integrated conceptual framework that refines the original JD-R model and that in doing so, better explicates the dynamics surrounding employee engagement and innovative behavior. Key implications for research and practice are provided.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Computers & Operations Research, Volume 112〈/p〉 〈p〉Author(s): Alexandre Salles da Cunha, Abilio Lucena〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Assume one is given an angle 〈em〉α〈/em〉 ∈ (0, 2〈em〉π〈/em〉] and a complete undirected graph 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si38.svg"〉〈mrow〉〈mi〉G〈/mi〉〈mo linebreak="goodbreak"〉=〈/mo〉〈mo〉(〈/mo〉〈mi〉V〈/mi〉〈mo〉,〈/mo〉〈mi〉E〈/mi〉〈mo〉)〈/mo〉〈/mrow〉〈/math〉. The vertices in 〈em〉V〈/em〉 represent points in the Euclidean plane. The edges in 〈em〉E〈/em〉 represent the line segments between these points, with edge weights equal to segment lengths. Spanning trees of 〈em〉G〈/em〉 are called 〈em〉α〈/em〉-spanning trees (〈em〉α〈/em〉-STs) if, for any 〈em〉i〈/em〉 ∈ 〈em〉V〈/em〉, the smallest angle that encloses all line segments corresponding to its 〈em〉i〈/em〉-incident edges does not exceed 〈em〉α〈/em〉. The Angular Constrained Minimum Spanning Tree Problem (〈em〉α〈/em〉-MSTP) seeks an 〈em〉α〈/em〉-ST with the least weight. The problem arises in the design of wireless communication networks operating under directional antennas. We propose two 〈em〉α〈/em〉-MSTP formulations. One, 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si39.svg"〉〈msub〉〈mi mathvariant="bold-script"〉F〈/mi〉〈mi〉x〈/mi〉〈/msub〉〈/math〉 requiring, in principle, 〈em〉O〈/em〉(2〈sup〉|〈em〉V〈/em〉|〈/sup〉) inequalities to model the angular constraints (〈em〉α〈/em〉-AC). For 〈em〉α〈/em〉 ∈ (0, 〈em〉π〈/em〉), however, we show that just 〈em〉O〈/em〉(|〈em〉V〈/em〉|〈sup〉3〈/sup〉) of them suffice to attain not only a formulation but also the same Linear Programming relaxation (LPR) bound as the full blown model. The other formulation, 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si40.svg"〉〈mrow〉〈msub〉〈mi mathvariant="bold-script"〉F〈/mi〉〈mrow〉〈mi〉x〈/mi〉〈mi〉y〈/mi〉〈/mrow〉〈/msub〉〈mo〉,〈/mo〉〈/mrow〉〈/math〉 enlarges the set of 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si39.svg"〉〈msub〉〈mi mathvariant="bold-script"〉F〈/mi〉〈mi〉x〈/mi〉〈/msub〉〈/math〉 variables but manages to model 〈em〉α〈/em〉-AC, compactly. Furthermore, 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si41.svg"〉〈msub〉〈mi mathvariant="bold-script"〉F〈/mi〉〈mrow〉〈mi〉x〈/mi〉〈mi〉y〈/mi〉〈/mrow〉〈/msub〉〈/math〉 LPR bounds are proven to dominate their 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si39.svg"〉〈msub〉〈mi mathvariant="bold-script"〉F〈/mi〉〈mi〉x〈/mi〉〈/msub〉〈/math〉 counterparts. That dominance, however, is empirically shown to reduce as 〈em〉α〈/em〉 increases. Finally, exact Branch-and-Cut algorithms implemented for the two formulations are shown, empirically, to exchange roles as top performer, throughout the [0, 2〈em〉π〈/em〉) range of 〈em〉α〈/em〉 values.〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 21 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Journal of Operational Research〈/p〉 〈p〉Author(s): Sturla F. Kvamsdal, José M. Maroto, Manuel Morán, Leif K. Sandal〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Seasonality or periodicity–biological, environmental, or economic–are fundamental properties of most marine fisheries. We propose a generic infinite horizon discrete time fisheries management model by modifying existing models and frameworks of analysis to reflect seasonal variation or more general multiperiodicity in parameters, variables, or functional forms. Our model captures such variations via repeated cycles of multiple intervals with differing characteristics. The framework offers a simple and intuitive set up of arbitrary periodicity and seasonality in any feature, which significantly increases model realism. Further, it distances itself from continuous time modeling approaches where uniqueness and solvability of periodic models generally are difficult to assert. In our setting, the governing equations for the time-dependent value function of the management optimization problem are shown to be equivalent to a high-dimensional contraction and hence ensure uniqueness and a feasible solution algorithm. We illustrate our approach using a simple example to demonstrate that accounting for seasonality in fisheries management can improve outcomes considerably. Our framework also provides for analysis of seasonal regulatory measures. Ultimately, our approach applies to renewable resource management more generally and to many infinite-horizon, discrete time optimization problems with periodic features.〈/p〉〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Air Transport Management, Volume 81〈/p〉 〈p〉Author(s): Mukesh Mohan Pandey, Divya Shukla〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The paper aims to identify and evaluate the factors influencing the human performance of Air Traffic Control (ATC) in Thailand. The objective of the study has been operationalized utilizing the extended SHEL model of ergonomics. Fuzzy Graded Mean Integration method has been employed to establish the importance and Fuzzy Additive Ratio Assessment method was utilized to measure actual performance of the factors on the response received from all ten air traffic control centers of Thailand. The finding of study facilitates the insights for improvement of various dimensions and constructs for an effective human performance management for ATC in Thailand. The study fulfills the theoretical gap by employing the Fuzzy Multi Criteria Decision Making (MCDM) method of identifying and measuring human performance in ATC.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 9 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Environmental Economics and Management〈/p〉 〈p〉Author(s): John K. Stranlund, James J. Murphy, John M. Spraggon, Nikolaos Zirogiannis〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉We present results from laboratory emissions permit markets designed to investigate the transmission of abatement cost risk to firms' compliance behavior and regulatory enforcement strategies. With a fixed expected marginal penalty, abatement cost shocks produced significant violations and emissions volatility as predicted. Tying the monitoring probability to average permit prices effectively eliminated noncompliance, but transmitted abatement cost risk to monitoring effort. Tying the penalty to average prices reduced violations, but did not eliminate them. Some individuals in these treatments sold permits at low prices, presumably in an attempt to weaken enforcement. While tying sanctions directly to prevailing permit prices has theoretical and practical advantages over tying monitoring to prices, our results suggest that tying sanctions to prices may not be as effective as predicted without additional modifications.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Ecological Economics, Volume 166〈/p〉 〈p〉Author(s): Mike Farjam, Olexandr Nikolaychuk, Giangiacomo Bravo〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉So far, there has been mixed evidence in the literature regarding the relationship between environmental attitudes and actual ‘green’ actions, something known as the attitude-behavior gap. This raises the question of when attitudes can actually work as a lever to promote environmental objectives, such as climate change mitigation, and, conversely, when other factors would be more effective. This paper presents an online experiment with real money at stake and real-world consequences designed to test the effect of environmental attitudes on behavior under various conditions. We found that environmental attitudes affected behavior only in low-cost situations. This finding is consistent with the low-cost hypothesis of environmental behavior postulating that concerned individuals will undertake low-cost actions in order to reduce the cognitive dissonance between their attitudes and rational realization of the environmental impact of their behavior but avoid higher-cost actions despite their greater potential as far as environmental protection. This finding has important consequences for the design of more effective climate policies as it puts limits on what can be achieved by raising environmental concern alone.〈/p〉〈/div〉

Description: 〈p〉Publication date: September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Air Transport Management, Volume 80〈/p〉 〈p〉Author(s): 〈/p〉

Description: 〈p〉Publication date: September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Transportation Research Part E: Logistics and Transportation Review, Volume 129〈/p〉 〈p〉Author(s): Son Nguyen, Peggy Shu-Ling Chen, Yuquan Du, Wenming Shi〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Uncertainty is a fundamental obstacle in container shipping operational risks (CSORs) evaluation and management. This study presents a model to quantitatively analyze CSORs with comprehensive uncertainty handling. The model features a Delphi risk communication platform (RCP) designed to establish a deliberative environment for expert interaction and cooperation. The risk level is assessed through a Bayesian network while a fuzzy-based system is implemented to evaluate the attached base of knowledge. Besides the validation of reliability and robustness by a sensitivity analysis, the conducted case study confirms the feasibility and functionality of the model, especially the impact of the implemented Delphi RCP.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Ecological Economics, Volume 166〈/p〉 〈p〉Author(s): Felipe Luiz Lima de Paulo, Pedro Jorge Sobral Camões〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This paper addresses the influence of ecological fiscal transfers (EFT) on the policy-making process of adopting local protected areas (PA) by municipal governments. Framed on the transaction-cost politics (TCP), it argues that an EFT schema designed at the state level may affect the expected payoff/costs of local level decisions and the time length to create PA. The mixed research design is composed of two parts: first, a descriptive analysis detailing the evolution of EFT in the state of Minas Gerais since the beginning until its current version; second, an event history analysis of municipal PA adoption from 1966 to 2013. The conclusion suggests that, while there is an overall increase in municipal PA after the introduction of EFT, some design aspects of the instrument such as uncertainty and monitoring costs slowed and flattened that increase.〈/p〉〈/div〉

Description: 〈p〉Publication date: December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Computers & Operations Research, Volume 112〈/p〉 〈p〉Author(s): Kuo-Hwa Chang, Michael Nayat Young〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This study exploits the extra information provided by behavioral stocks (B-stocks) and proposes portfolio selection models that produce profitable portfolios which can outperform traditional investment benchmarks (market index, mutual funds, and exchange-traded funds). Using the embedded holding period (〈em〉T〈/em〉-day) information of a B-stock, in order to maximize the expected effect (cumulative abnormal return 〈em〉CAR〈/em〉  ≥ 1%), this study proposes a buy and hold strategy such that B-stocks are bought when their respective causes are spotted and held until their respective 〈em〉T〈/em〉-days are reached. In addition, in performing the back-tests the actual transaction costs are considered to represent more realistic investments. Short-selling is also considered to provide a more flexible investment such that some B-stocks are shorted when causes are spotted and wait until their respective 〈em〉T〈/em〉-days are reached to exploit the expected effect (〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si8.svg"〉〈mrow〉〈mi〉C〈/mi〉〈mi〉A〈/mi〉〈mi〉R〈/mi〉〈mo〉≤〈/mo〉〈mo〉−〈/mo〉〈mn〉1〈/mn〉〈mo〉%〈/mo〉〈/mrow〉〈/math〉). The resulting portfolios are then compared to traditional benchmarks. Overall, this study addresses three issues that were not addressed by previous works on B-stocks. These issues are: (1) having portfolios that are profitable even after all transactions costs are considered; (2) identifying short-sell B-stocks for consideration of short-selling in the portfolio selection; and (3) generating portfolios that outperform traditional investment benchmarks.〈/p〉〈/div〉

Description: 〈p〉Publication date: December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Computers & Operations Research, Volume 112〈/p〉 〈p〉Author(s): Everton Fernandes Silva, Larissa Tebaldi Oliveira, José Fernando Oliveira, Franklina Maria Bragion Toledo〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Cutting phases occur in many production processes when a larger object must be cut into multiple smaller pieces. Some examples of relevant industries being clothing, footwear, metalware and furniture. The cutting phase is composed of two stages. The first stage consists of finding a good layout for the set of small pieces that must be cut from the larger object and minimizing some objective such as raw-material waste (The Cutting and Packing Problem). Once this good layout has been established, it is provided as input for the second stage which consists of determining the path to cut the pieces which minimizes another objective, such as the total cutting time or distance (The Cutting Path Determination Problem). This second stage is crucial for efficient production planning. Only one linear mathematical model has previously been proposed for the Cutting Path Determination Problem. In this paper, this problem is addressed using two exact approaches based on the Rural Postman Problem (RPP) and the Traveling Salesman Problem (TSP). The RPP approach, in particular, is able to produce optimal solutions for instances containing more than 2000 edges in under 1 h.〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 20 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Journal of Operational Research〈/p〉 〈p〉Author(s): Chandra Ade Irawan, Majid Eskandarpour, Djamila Ouelhadj, Dylan Jones〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Scheduling maintenance routing for an offshore wind farm is a challenging and complex task. The problem is to find the best routes for the Crew Transfer Vessels to maintain the turbines in order to minimise the total cost. This paper primarily proposes an efficient solution method to solve the deterministic maintenance routing problem in an offshore wind farm. The proposed solution method is based on the Large Neighbourhood Search metaheuristic. The efficiency of the proposed metaheuristic is validated against state of the art algorithms. The results obtained from the computational experiments validate the effectiveness of the proposed method. In addition, as the maintenance activities are affected by uncertain conditions, a simulation-based optimisation algorithm is developed to tackle these uncertainties. This algorithm benefits from the fast computational time and solution quality of the proposed metaheuristic, combined with Monte Carlo simulation. The uncertain factors considered include the travel time for a vessel to visit turbines, the required time to maintain a turbine, and the transfer time for technicians and equipment to a turbine. Moreover, the proposed simulation-based optimisation algorithm is devised to tackle unpredictable broken-down turbines. The performance of this algorithm is evaluated using a case study based on a reference wind farm scenario developed in the EU FP7 LEANWIND project.〈/p〉〈/div〉

Description: 〈p〉Publication date: January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Ecological Economics, Volume 167〈/p〉 〈p〉Author(s): Michael J. Bloomfield〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉While there is a substantial body of research focused on the links between North-South trade and sustainable development, research on South-South trade and sustainable development is still in its infancy. Given current understandings of the drivers of sustainable development, one might expect increasing trade in agricultural commodities within the global South to have a negative impact on sustainable development opportunities. In this sense, the Ceylon tea industry presents a puzzle. Despite exporting most of its tea to Southern markets, it has been among the top performers in terms of economic, social, and environmental practices. As such, the case raises a number of questions around shifting trade patterns and their implications for sustainability outcomes. I address these questions through four propositions – three mechanisms and one condition – through which South-South trade can expand the opportunities for sustainable development. While the exact nature of sustainable development outcomes will ultimately be decided through domestic political struggles, shifts toward more equal trade can make sustainable production more likely. Overall, the analysis draws attention to nuanced ways in which end markets shape their respective supply chains and how these dynamics impact the potential for actors operating at the bottom of supply chains to shape sustainability outcomes.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Ecological Economics, Volume 164〈/p〉 〈p〉Author(s): Mohammad Shakhawat Hossain, Muhammad Arshad, Lu Qian, Minjuan Zhao, Yasir Mehmood, Harald Kächele〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Climate change may influence crop income negatively or positively. To address this, present study is an attempt to quantify the impacts of climate change on net income from crop farming in Bangladesh using Ricardian method. For estimating the relationship between net crop income and climatic parameters, farm household and climate data were collected from the selected agro-ecological zones (AEZs) in Bangladesh. The results revealed that net crop income is sensitive to climate, particularly to seasonal temperature. Temperature rise was found to be positively influencing net crop income in AEZs having adequate irrigation facilities. Marginal impact estimates suggest that increase in temperature and rainfall will lead to increase in net income from crop farming in Bangladesh. However, the impacts will vary significantly across cropping seasons and space (studied AEZs). Using selected AOGCM scenarios, the study predicts that net crop incomes are expected to increase in the future. The empirical findings underscore the need for policy makers to take agro-ecological zones specific effects of climate change into consideration when formulating and implementing the adaptation strategies in Bangladesh.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 21 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy Economics〈/p〉 〈p〉Author(s): Christiane Münzel, Patrick Plötz, Frances Sprei, Till Gnann〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Plug-in electric vehicles (PEV), both as battery electric vehicles and plug-in hybrid vehicles have noteworthy potential to reduce global and local emissions. However, several barriers still hinder a fast market diffusion of this new technology. Governments around the world have implemented monetary and non-monetary policies to accelerate PEV market diffusion. Their effectiveness is established in the literature, yet the effect size has been only scarcely estimated empirically and only for the US. Here, we review econometric studies on the effect size of purchase incentives and analyse data on PEV sales from 32 European countries from 2010 to 2017 with respect to the effect of financial incentives. We apply panel data regressions and control for other factors such as income and fuel prices. We find energy prices and financial incentives to influence PEV adoption positively. The range of point estimates for the effect of incentives is 5–7% relative sales share increase in different model specifications. Methodologically, the inclusion of a trend variable proved important to capture overall changes in the diffusion of this new technology. Our findings indicate that financial incentives have an impact on PEV sales and thus can facilitate their diffusion.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Geoforum, Volume 106〈/p〉 〈p〉Author(s): Monica Vasile〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This article examines the transformations of the contemporary postsocialist forests of the Romanian Carpathian Mountains, focusing on contentious resource politics in the context of new dynamics of forest commodification. I argue that in the last decades the political forests of the Carpathians emerged as fiefdom forests, territories of intense domestic extraction driven by patron-client relations, which are marked by provincial authoritarianism, labor vulnerability and limited freedom. Drawing on insights from long-term anthropological research, this article sheds light on the contours of coercive power relations in extractive territories, revealing the entanglements between politics and forests in the realm of a shadow state. Local timber economies go from boom to bust, exhausting the environment. Local voices of dissent can barely be heard, resistors suffering repression and incorporation. Fought through a legal-political repertoire and predicated upon rights to commons and distributional justice, the resistance is tangled in politics of evidence driven by corrupt institutions and biased judiciary systems. Throughout the paper, the story of the fiefdom forests follows three main threads: (1) the rise of an elite group of timber barons, local entrepreneurs, loggers and foresters who control the forests, and accumulate power and capital, connected to the rise of authoritarian polities; (2) the experiences of small forest operators and workers, their vulnerabilities and dependency upon forest jobs, ridden with repression and violence; (3) the makeshift roads of local resistance and political struggle, revealing the limits of freedom and the internal divisions of community. The article contributes to recent scholarship that links resource extraction, authoritarianism and rural resistance.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 19 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Omega〈/p〉 〈p〉Author(s): Lili Yu, Xiuli He, Juan Zhang, Chuanyong Xu〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The advertising threshold effect, which implies that advertising has little effect on sales if the level of advertising is below a certain level, has seldom been addressed in a modeling context. Inspired by the practice of horizontal cooperative advertising (HCA), this paper attempts to investigate the advertising threshold effect in a horizontal context and to explore the value of HCA programs. To investigate the advertising threshold effect in a horizontal context, we develop several advertising and pricing models that involve two horizontally related firms, where the advertising threshold effect is formulated by a two-regime sales function. We first consider the monopoly case and then extend it to a duopoly case. We further consider two HCA programs to explore the value of such programs, in which the firms share advertising expenditures to reduce their advertising cost. The findings include the following: (i) The presence of an advertising threshold can lead to sub-optimal advertising decisions. (ii) If one firm is influenced by the advertising threshold, this influence may be passed to its competitor. (iii) Although cooperative advertising is less cost effective than individual brand advertising, firms can benefit from HCA programs only when the advertising threshold is neither too high nor too low, and the synergy effect of cooperative advertising is not too low.〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 20 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Long Range Planning〈/p〉 〈p〉Author(s): Merriam Haffar, Cory Searcy〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Tensions between economic, environmental, and social performance are inherent to the practice of corporate sustainability. These sustainability tensions present the company with stratc choices. Using an organizational cognition perspective, we posit that companies interpret and respond to these tensions in ways that reflect an underlying collective sustainability logic. The purpose of this research is to explore this link, and to describe the logics that companies use when approaching sustainability tensions—and in doing so, explore what this reveals about the nature of the logics themselves. To achieve this, we perform a qualitative content analysis of interviews with sustainability managers, as well as archival documents. We find that all companies, regardless of their sustainability logic, encounter tensions in the practice of sustainability. In navigating these tensions, companies following a market-led logic tended to consider a narrow scope of stakeholder interests in their sustainability decision-making. These companies also followed a mutually-exclusive (and unintegrated) ‘if/then’ approach to sustainability tensions. On the other hand, companies that followed a holistic logic tended to consider a much wider scope of stakeholders and displayed a higher degree of integration in their logic (i.e., synergetic approach to decision-making around tensions).〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 20 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Journal of Operational Research〈/p〉 〈p〉Author(s): Simon J. Höller, Raik Özsen, Ulrich W. Thonemann〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Order expediting is an inventory control practice that allows companies to reduce inventory while maintaining service levels. However, expediting outstanding orders is costly and a trade-off must be made between expediting orders and holding inventory. We model the problem as a periodic-review inventory system with the option to move outstanding units forward in the replenishment pipeline. The objective is to minimize the sum of expected inventory holding and expediting costs per period subject to a minimum expected service level constraint. We consider a generalized base-stock policy where outstanding units are expedited when the inventory level drops below a certain threshold. We develop structural properties and present an efficient procedure to determine the optimal policy parameters. In a numerical study with real-world data, we show that our expediting policy offers substantial savings compared to other policies. We also provide managerial insights by numerically analyzing how the model parameters impact the savings.〈/p〉〈/div〉

Description: 〈p〉Publication date: January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Computers & Operations Research, Volume 113〈/p〉 〈p〉Author(s): J. Martinovic, M. Delorme, M. Iori, G. Scheithauer, N. Strasdat〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Thanks to the rapidly advancing development of (commercial) MILP software and hardware components, pseudo-polynomial formulations have been established as a powerful tool for solving cutting and packing problems in recent years. In this paper, we focus on the one-dimensional skiving stock problem (SSP), where a given inventory of small items has to be recomposed to obtain a maximum number of larger objects, each satisfying a minimum threshold length. In the literature, different modeling approaches for the SSP have been proposed, and the standard flow-based formulation has turned out to lead to the best trade-off between efficiency and solution time. However, especially for instances of practically meaningful sizes, the resulting models involve very large numbers of variables and constraints, so that appropriate reduction techniques are required to decrease the numerical efforts. For that reason, this paper introduces two improved flow-based formulations for the skiving stock problem that are able to cope with much larger problem sizes. By means of extensive experiments, these new models are shown to possess significantly fewer variables as well as an average better computational performance compared to the standard arcflow formulation.〈/p〉〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Transportation Research Part B: Methodological, Volume 128〈/p〉 〈p〉Author(s): Evženie Suzdaleva, Ivan Nagy〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This paper deals with the task of modeling the driving style depending on the driving environment. The model of the driving style is represented as a two-layer mixture of normal components describing data with two pointers: outer and inner. The inner pointer indicates the actual driving environment categorized as “urban”, “rural” and “highway”. The outer pointer through the determined environment estimates the active driving style from a fuel economy point of view as “low consumption”, “middle consumption” and “high consumption”. All of these driving styles are assumed to exist within each driving environment due to the two-layer model. Parameters of the model and the driving style are estimated online, i.e., while driving using a recursive algorithm under the Bayesian methodology. The main contributions of the presented approach are: (i) the driving style recognition within each of urban, rural and highway environments as well as in the case of switching among them; (ii) the two-layer pointer, which allows us to incorporate the information from continuous data into the model; (iii) the potential use of the data-based model for other measurements using corresponding distributions. The approach was tested using real data.〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 22 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Computers & Operations Research〈/p〉 〈p〉Author(s): Faisal Alkaabneh, Ali Diabat, Huaizhu Oliver Gao〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉We consider the problem of inventory routing in the context of perishable products and find near-optimal replenishment scheduling and vehicle routes when the objective is to maximize the supplier’s profit and minimize the costs due to fuel consumption, inventory holding, and greenhouse gas emissions. Greenhouse gas emissions are calculated as a function of fuel consumed, and fuel consumption levels are accurately calculated as a function of vehicle speed, load and traveled distance. To solve the problem efficiently, we develop an exact method based on Benders decomposition to find high-quality solutions in reasonable time. To enhance the convergence rate of the Benders decomposition algorithm, we present several acceleration strategies, such as addition of valid inequalities to the master problem and warm-up start. The warm-up start acceleration strategy itself is a meta-heuristic based on the greedy random adaptive search procedure (GRASP) and mathematical programming formulations. We present computational results which illustrate the superior performance of the proposed solution methodology in solving large-scale instances with 60 customers and 6 planning periods with 4 vehicles using Benders decomposition. Additionally, we show that utilizing a more comprehensive model to calculate the fuel cost results in fuel savings of 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si4.svg"〉〈mrow〉〈mn〉2〈/mn〉〈mo linebreak="goodbreak"〉−〈/mo〉〈mn〉11〈/mn〉〈mo〉%〈/mo〉〈/mrow〉〈/math〉 on the tested instances compared to traditional models that assume that the fuel cost is solely a function of the distance traveled during delivery.〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 20 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Journal of Operational Research〈/p〉 〈p〉Author(s): M. Fampa, D. Lubke, F. Wang, H. Wolkowicz〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉We consider a parametric convex quadratic programming (CQP) relaxation for the quadratic knapsack problem (QKP). This relaxation maintains partial quadratic information from the original QKP by perturbing the objective function to obtain a concave quadratic term. The nonconcave part generated by the perturbation is then linearized by a standard approach that lifts the problem to matrix space. We present a primal-dual interior point method to optimize the perturbation of the quadratic function, in a search for the tightest upper bound for the QKP. We prove that the same perturbation approach, when applied in the context of semidefinite programming (SDP) relaxations of the QKP, cannot improve the upper bound given by the corresponding linear SDP relaxation. The result also applies to more general integer quadratic problems. Finally, we propose new valid inequalities on the lifted matrix variable, derived from cover and knapsack inequalities for the QKP, and present separation problems to generate cuts for the current solution of the CQP relaxation. Our best bounds are obtained alternating between optimizing the parametric quadratic relaxation over the perturbation and applying cutting planes generated by the valid inequalities proposed.〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 20 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy Economics〈/p〉 〈p〉Author(s): Sufang Li, Hu Zhang, Di Yuan〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Using the Google search volume index (GSVI) to measure investor attention, this paper investigates the relationships between investor attention and crude oil prices for the main crude oil markets worldwide. To account for possible structural breaks and nonlinearity in the relation between investor attention and oil returns, Fourier unit root test and nonlinear Granger causality tests are employed. The empirical results suggest that the bidirectional nonlinear Granger causality exists only between investor attention and WTI future crude oil return. However, WTI crude oil return Granger-causes investor attention weakly. For Dubai spot, Daqing spot, WTI spot and Brent future oil markets, unidirectional nonlinear Granger causality runs from investor attention to oil returns, which is relatively weak.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Ecological Economics, Volume 166〈/p〉 〈p〉Author(s): Johannes Wegmann, Oliver Mußhoff〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Many aquifers in semi-arid and arid regions with rapid urbanization are over-exploited or even at the point of depletion. Driven by the increased demand for food and other agricultural products, irrigated agriculture constitutes the biggest user of groundwater, and has thus contributed to this critical situation. In this paper, we compare different designs of groundwater management institutions in order to avoid aquifer over-exploitation and ensure secure water sources. We assess externally imposed reward-based and punishment rules as well as communication on their effectiveness to reduce water extraction behavior of groundwater users. Moreover, we evaluate how different user types affect the outcome of these institutional designs. To do so, we conducted a framed field experiment with 600 households along the rural-urban interface of the fast growing city of Bengaluru, India. Results indicate that all treatments can prolong the life of the resource but reward-based and punishment rules seem to be more effective than communication. Moreover, we find that user type behavior identified in the baseline trial is persistent in the treatment trial despite interventions.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 20 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Journal of Operational Research〈/p〉 〈p〉Author(s): Yusuke Zennyo〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This paper examines strategic contracting between a monopoly platform and suppliers that sell their goods through the platform. I consider two competing suppliers: a high-volume supplier with the larger potential demand and a low-volume supplier with the smaller one. Each supplier chooses one of two contracts: wholesale or agency. The platform has to strategically determine the royalty rate for the agency contract by taking into account which contracts the suppliers will choose. I show that the platform offers a low (high) royalty rate to induce the suppliers to adopt the agency (wholesale) contract when product substitutability is low (high) enough. More interestingly, when the degree of substitution is at an intermediate level, asymmetric contracting, in which only the low-volume supplier adopts the agency contract, can arise in equilibrium. This result is related to the fact that many long-tail and niche products with lower potential market sizes are traded on platform-based marketplaces, such as Amazon Marketplace and Walmart Marketplace.〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 19 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Human Resource Management Review〈/p〉 〈p〉Author(s): Ina Aust, Brian Matthews, Michael Muller-Camen〈/p〉

Description: 〈p〉Publication date: Available online 31 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Journal of Operational Research〈/p〉 〈p〉Author(s): Shu Guo, Tsan-Ming Choi, Bin Shen〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Motivated by the observed industrial issues, we analytically develop a fashion supply chain consisting of one manufacturer and two competing retailers and investigate how retail competition and consumer returns affect green product development in fashion apparel. In the basic model, that is, the pure “product greenness level” game, we find that the optimal greenness level of the fashion product decreases along with the level of market competition. This finding implies that a more competitive market leads to a lower optimal greenness level. We also identify that when the consumer return rate increases, the optimal product greenness level is substantially reduced. In the extended model with joint decisions on greenness and pricing, we find that the optimal product greenness level for the whole channel is always higher in the scenario when both retailers charge a higher retail price than in the case with a lower retail price. As such, the underdevelopment of green fashion products is a result of fashion industry features, such as an extremely competitive environment for green product development, relatively low retail prices for fashion products, and high consumer return rates. Therefore, fashion companies should join a co-opetition game for the green product market and simultaneously enhance their efficiency in managing consumer returns. To support our analytical findings, we conduct extensive industrial interviews with various representative companies. Based on this multi-methodological approach (MMA), this paper generates practice-relevant managerial insights that not only contribute to the literature, but also act as valuable references for industrialists.〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 31 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Journal of Operational Research〈/p〉 〈p〉Author(s): Daqiang Chen, Joshua Ignatius, Danzhi Sun, Mark Goh, Shalei Zhan〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This paper addresses the problem of the firms operating on cross-border or inter-regional platforms that are subject to the enforcement of each local government's carbon emissions regulatory policy, thus causing an imbalance in the sharing of the burden of the greening of the total supply chain. We introduce the concept of equity as the incentive mechanism to coordinate this green supply chain which is a function of the carbon emission permits and the revenue generated by the firms. Due to the complexity and imbalance in the original incentive mechanism to this problem, we provide a new equivalent supply chain network equilibrium model under elastic demand based on user equilibrium theory. We state the user equilibrium conditions and provide the equivalent formulation. We show the trade-offs under various carbon emissions regulatory policies. A product with higher price elasticity and carbon emission intensity not only hampers the firm from gaining a higher revenue, but it also reduces the equity of the system under an invariant emission regulatory policy.〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 1 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Production Economics〈/p〉 〈p〉Author(s): Xing Bao, Ali Diabat, Zhongliang Zheng〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this paper, we study the manager's decisions in mitigating the disruption of the operation system when its operating units (OUs) were crippled by the unexpected event. Manager's ambiguity in making decision during the recovery phase might rise in two aspects: first, the level of remaining OUs might fluctuate due to uncontrollable ripple effects, and second, the lack of sufficient historic disruption data. In this study, the ambiguous manager is described as the Choquet one whose ambiguity belief is represented by the Choquet expect utility. Through the single- and multi-periods recovery models, we show that the Choquet manager consistently procures more short-term OUs from his capacity-shared partners than the rational one, and tends to build a higher redundant inventory level in the pre-disruption phase. To investigate the impact of insufficient demand data on the decisions of the Choquet manager in the recovery phase, we adopt two Bayesian learning methods to dynamically update the ambiguity belief in a multi-periods setting: first, the Beta method (a parametric method), and second, the minimum relative entropy (MRE) method (a nonparametric, also a data-driven method). Numerical results present findings in three aspects: First, the MRE method provides more robust estimations than the Beta one, and hence, it leads to a lower disruption cost because of its better approximation to the distribution of the uncertainty. Second, the initial redundant inventory does not contribute as much to lower the disruption cost as shortening the recovery time. Third, there is an “〈em〉anchoring effect〈/em〉” when the manager's follow-up decisions are anchored on previous estimations of the uncertainties mean value.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 28 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Journal of Operational Research〈/p〉 〈p〉Author(s): Noemie Balouka, Izack Cohen〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This paper suggests a robust optimization approach for the multi-mode resource-constrained project scheduling problem with uncertain activity durations. The objective is to minimize the worst-case project duration by deciding on activity modes, resource allocations and a schedule baseline. The problem is solved by a Benders decomposition approach with specialized cuts. We consider polyhedral uncertainty sets in which the level of conservatism can be adjusted. Using a computational study in which various problem instances are explored under varying levels of uncertainty, conservatism and several types of duration distributions, we provide insights about the price of robustness and the performance of the approach. The hope is that these insights can guide future multi-mode project scheduling implementations when there is partial information about the distribution of activity durations.〈/p〉〈/div〉

Description: 〈p〉Publication date: November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Geoforum, Volume 106〈/p〉 〈p〉Author(s): Huiwen Gong, Xiaorui Xin〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉While previous research on clusters has shed light on innovation at macro and meso levels, little research has explored the impact of co-location for individual creativity. Additionally, the significance of tranquility and solitude for creativity also remains largely unexplored. To explore these two aspects, this paper examines forces that matter for the creativity of game workers in Shanghai. The results manifest that, online platforms and learning through projects play a noticeable role for the individual creativity of game developers. While the value of co-location and local buzz has been stressed much in the literature, it turns out to be less significant for the creativity of most creative workers. Similarly, the role of attending temporary events is found to be less important as it claimed to be. Whereas research on the impact of tranquility and solitude for individual creativity has not been taken up sufficiently in economic geography, this research attaches high value to places and moments that creative workers can retreat from the buzzy environment to recover from attention fatigue.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Geoforum, Volume 106〈/p〉 〈p〉Author(s): Johan Jansson〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This paper focus on the concept of curation that emphasizes intermediary processes sorting and filtering the information overload that characterize contemporary digitalized society. The paper has two overall aims. The first aim is theoretical and the ambition is to identify practices and processes distinctive to curation in digital spaces. From this literature the paper argues that contemporary digital curation is characterized by (a) digitally produced and mediated processes, (b) de-professionalization, (c) a combination of productive and consumptive modes, (d) space as a ‘quality stamp’, and (e) an increasingly underlying and/or everyday practice. The second aim is empirical and, through a case study of an online forum dedicated to hi-fi and high-end audio equipment, the ambition is to identify curatorial practices and processes taking place at the forum and to understand how the online forum functions as a curatorial space. More specifically, in the analysis of the empirical material three themes are highlighted. First, personal consumer experiences are expressed through narrated purchases in which the constant pursuit of the ‘perfect audio reproduction system’ is materialized as these narratives involve with the explanations and motivations behind personal reflections and experiences of purchase decisions. Second, the online forum has clear power structures. Third, the online forum deals with geographical dimensions in several ways, e.g. by functioning as a space for legitimization where the lack of distance and the use of (partially) anonymous profiles generate both advantageous and disadvantageous dimensions.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 16 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Omega〈/p〉 〈p〉Author(s): Chenbo Zhu, JianQiang Hu〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In 2007, the Chinese aviation authority asked the five airlines that offer service between Shanghai and Beijing to form an express shuttle alliance so that tickets from one airline could be used for any flight offered by any of the other airlines. In this paper, we study the impact of such a government mandate on the competitiveness of the market and on airline operations. First we extend a competitive airline seat allocation model to include such a government mandate and provide sufficient conditions for the existence of a pure-strategy Nash equilibrium in such a model. Both our analytical and numerical results show that fewer low-fare seats would be made available in a market with the government mandate, and furthermore, revenues of individual airlines would be lower as well. We then study a seat inventory and price competition game between duopoly airlines with the government mandate and establish the existence of pure-strategy Nash equilibriums. We show that with the government mandate, the airlines would reserve more high-fare seats and raise the prices of high-fare seats. In addition, we show that the revenues of the airlines would decrease as fewer low-fare seats are offered and increase as the prices of high-fare seats are increased. We also discuss how the government mandate should be designed so that the market could operate as efficiently as possible.〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 16 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy Economics〈/p〉 〈p〉Author(s): Panbo Guan, Guohe Huang, Chuanbao Wu, Linrui Wang, Chaoci Li, Yuanyi Wang〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this study, an inexact two-stage chance-constrained programming (ITSCCP) model was provided for multiple electrical power system supply and demand management in Zibo City under uncertainties. Three scenarios about the electric power structure adjustment, renewable power generation, and the emission taxes were designed. Methods of two-stage stochastic programming (TSP) and inexact chance-constrained programming (ICCP) were incorporated into the developed model to tackle uncertainties in terms of various cost coefficients, decision maker's risk attitude which was described by interval values and probability distributions. Moreover, under the objective of cost minimize, the electrical power generation planning for each terms under different feasibility degrees (violating constraints or available resources situations) can be obtained. The results indicated that higher probability of violating system constraints would increase risk of system, but lower the total cost; the proportion of optimized thermal power generation and imported electricity would decrease, which could promote the energy conservation and emissions reduction in some degree. At the same time, the model results are valuable for decision-makers to tackle the uncertainty of the power generation schemes within a complicated energy system and make a desired compromise between the satisfaction degree of the economic benefits and feasibility degree of constraints.〈/p〉〈/div〉

Description: 〈p〉Publication date: December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Computers & Operations Research, Volume 112〈/p〉 〈p〉Author(s): David García-Heredia, Antonio Alonso-Ayuso, Elisenda Molina〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this paper we introduce a new 0–1 mathematical formulation for the Air Traffic Flow Management problem. The model is based on a 4D-graph, which allows us to consider the problem not as general combinatorial one, but as a set of shortest path problems with common capacity constraints, a fact that introduces several neat features. Among the decisions considered in the model are ground and air delays, changes in the speed of the aircraft and alternative routes. The proposed model, in comparison with the current state of the art, is shown to be an easy way to model different real complex situations (e.g., more realistic representation of costs and decisions involved, as well as dynamic sector configuration). The rapidity with which the computations are performed in this model shows the applicability of our proposal to the industry.〈/p〉〈/div〉

Description: 〈p〉Publication date: December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Computers & Operations Research, Volume 112〈/p〉 〈p〉Author(s): Victor Fernandez-Viagas, Jose M. Framinan〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this paper, we analyse several issues concerning the most efficient approximate algorithms for the permutation flowshop scheduling problem with makespan objective. On the one hand, it is not clear which algorithm obtains the best solutions for the problem, since (1) conflicting results have been reported regarding the implementation of a key part in one of these algorithms (the FF tie-breaking mechanism by Fernandez-Viagas and Framinan, 2014), and (2) some recent contributions have appeared independently, so they have not been compared so-far. On the other hand, since all these efficient methods consist of specialised variants of an iterated greedy algorithm, it is worth exploring if their specific features can be efficiently combined so a new, best-of-breed algorithm can be designed. These questions are addressed in this paper by first conducting an extensive comparison among the best-so-far algorithms (including a detailed description of the FF tie-breaking algorithm and the posting of its source codes to ensure full reproducibility), and then by designing a best-of-breed combination of these algorithms. The computational experience carried out shows that the new algorithm designed significantly outperform existing ones, thus being the best-so-far approximate method for the problem.〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 15 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy Economics〈/p〉 〈p〉Author(s): Niels Govaerts, Kenneth Bruninx, Hélène Le Cadre, Leonardo Meeus, Erik Delarue〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In many countries, distribution grid tariffs are being reformed to adapt to the new realities of an electricity system with distributed energy resources. In Europe, legislative proposals have been made to harmonize these reforms across country borders. Many stakeholders have argued that distribution tariffs are a local affair, while the European institutions argued that there can be spillovers to other countries, which could justify a more harmonized approach. In this paper, we quantify these spillovers in a simplified numerical example to give insight and an order of magnitude. We look at different scenarios, and find that the spillovers can be both negative and positive. To be able to quantify these effects, we developed a long-run market equilibrium model that captures the wholesale market effects of distribution grid tariffs. The problem is formulated as a non-cooperative game involving consumers, generating companies and distribution system operators in a stylized electricity market.〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 15 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy Economics〈/p〉 〈p〉Author(s): Xian Xi, Jinsheng Zhou, Xiangyun Gao, Donghui Liu, Huiling Zheng, Qingru Sun〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Crude oil is one of the most important energy sources for the development of the national economy. The regions along the Belt and Road are rich in crude oil resources. As the Belt and Road Initiative (B&R Initiative) progresses and develops further, an increasing numbers of countries are participating, which thus increases trade cooperation and changes the pattern of crude oil trade among countries along the Belt and Road (B&R countries). This change will have various impacts on the economies of different countries. Based on the complex network and econometric theory, we study the impact of crude oil trade pattern changes of the B&R countries on each country's GDP. We obtained the following results: (1) The impact of national trade influence on GDP was significant and positive, particularly after the initiative was proposed. (2) The centrality of the country's role in the trade network had a significant and favorable impact on GDP, but it was weakened after the initiative was introduced. (3) The impact of the country's import risk in the network on GDP was negative. (4) For countries with different economic levels, changes in the role of national trade had various effects on their GDPs.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 13 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Journal of Operational Research〈/p〉 〈p〉Author(s): Gilberto Montibeller, Pratik Patel, Victor J. del Rio Vilas〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Multi-criteria assessments are increasingly being employed in the prioritisation of health threats, supporting decision processes related to health risk management. The use of multi-criteria analysis in this context is welcome, as it facilitates the consideration of multiple impacts of health threats, it can encompass the use of expert judgment to complement and amalgamate the evidence available, and it permits the modelling of policy makers’ priorities. However, these assessments often lack a clear multi-criteria conceptual framework, in terms of both axiomatic rigour and adequate procedures for preference modelling. Such assessments are 〈em〉ad hoc〈/em〉 from a multi-criteria decision analysis perspective, despite the strong health expertise used in constructing these models. In this paper we critically examine some key assumptions and modelling choices made in these assessments, comparing them with the best practices of multi-attribute value analysis. Furthermore, we suggest a set of guidelines on how simulation studies might be employed to assess the impact of these modelling choices. We apply these guidelines to two relevant studies available in the health threat prioritisation domain. We identify severe variability in our simulations due to poor modelling choices, which could cause changes in the ranking of threats being assessed and thus lead to alternative policy recommendations than those suggested in their reports. Our results confirm the importance of carefully designing multi-criteria evaluation models for the prioritisation of health threats.〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 13 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Journal of Operational Research〈/p〉 〈p〉Author(s): Antoine Lesage-Landry, Joshua A. Taylor〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉We construct a model for transmission planning with both alternating and direct current lines, the latter of which can be interfaced via either line-commutated converters or voltage-source converters. The transmission expansion problem is nonlinear and nonconvex. Thus, nonlinear solvers cannot guarantee their convergence to the global optimum of the problem. We use relaxations and approximations to formulate a mixed-integer second-order cone transmission expansion model, which can be solved to optimality by current industrial solvers. We base our formulation on the branch flow relaxation. We include losses and reactive power placement, and consider direct current lines connected by both line-commutated converters and voltage-sourced converters. We show that our approach lowers the expansion cost on 6-bus and 24-bus system examples. We evaluate the feasibility of our formulation using a semidefinite relaxation of optimal power flow and find that the resulting plan admits feasible or close to feasible power flows.〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 13 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy Economics〈/p〉 〈p〉Author(s): Hany Abdel-Latif, Mahmoud El-Gamal〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This paper aims simultaneously to study the global dynamic relationship of oil prices, financial liquidity, and geopolitical risk, on the one hand, and the economic performance of oil-exports-dependent economies on the other. Global and country-specific dynamics are studied together in a Global Vector Autoregression (〈em〉GVAR〈/em〉) model that allows different lag structures for different variables in different countries. Global impulse response functions from the estimated model suggest that new waves of high oil prices are unlikely, despite the likely continuation of high global financial liquidity and heightened geopolitical risk, which had driven earlier episodes of very high oil prices. With oil remaining at modest to low prices by recent historical standards, we study the prospects for economic growth in oil-export-dependent economies through dramatic increases in domestic investment, as planned under Visions 2030 of some Arab countries, and conclude that, unfortunately, success is unlikely.〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 14 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy Economics〈/p〉 〈p〉Author(s): Fan Zhou, Lionel Page, Robert K. Perrons, Zuduo Zheng, Simon Washington〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The ability to forecast energy prices in the long-term is important for a wide range of reasons, from the formulation of countries’ energy and transportation policies to the defensive strategies of nations to investment decisions within the private sector. Despite the importance of these predictions, however, forecasters and market pundits face a difficult challenge when trying to forecast over the long-term. While statistical models can credibly rely on assumptions about the relationship between variables in the short-term, they are frequently less reliable in the long-term as political and technological transformations profoundly change how the economy works over time. Towards improving long-term predictions for energy commodities, this paper uses the elicitation and aggregation of experts’ beliefs to put forward forecasts for crude oil and natural gas prices by incentivizing experts to tell the truth and minimising their own biases through the application of the Bayesian Truth Serum. With this approach, we generated both short-term and long-term forecasts, and used the short-term forecast to validate the quality of the experts’ predictions.〈/p〉〈/div〉

Description: 〈p〉Publication date: December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Ecological Economics, Volume 166〈/p〉 〈p〉Author(s): Guillaume Lhermie, Didier Wernli, Peter Søgaard Jørgensen, Donald Kenkel, C.-Y. Cynthia Lin Lawell, Loren William Tauer, Yrjo Tapio Gröhn〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Antimicrobial use (AMU) in animal agriculture contributes to select resistant bacteria potentially transferred to humans directly or indirectly via the food chain, representing a public health hazard. Yet, a major difference triggering AMU in food animal production is that in addition to therapeutic cure, farmers use antimicrobials to keep their herds healthy and highly productive, while ensuring animal welfare and food safety objectives. As a society, we consequently face difficult tradeoffs, between massive restrictions of AMU, and maintenance of current and potentially non-sustainable consumption levels. Here, we present the different components to be addressed for assessing the sustainability of AMU in animal agriculture. At first, we describe the interests and limits of existing models identified by reviewing the literature, which could potentially be used to assess AMU sustainability, while allowing the reader to capture in a simple and visual manner the complexity of the issue. We address in the following sections the boundaries of the social-ecological system and the indicators that are required for assessment of AMU sustainability. We introduce analytic methods that could be used for assessing the sustainability of antimicrobial use.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 13 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Omega〈/p〉 〈p〉Author(s): Julio B. Clempner〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉Airline strategic alliances result in a form of cooperation where firms can access the resources of others network members in order to create added value for their passengers. The shortcoming of this process is that each member of the network makes individual revenue management decisions to maximize its own income, resulting in a sub-optimal income for the network members.〈/p〉 〈p〉To deal with this problem, this paper suggests a resource allocation based on a transfer pricing mechanism, to cooperatively divide the revenue of a passenger between network members. The method penalizes the total time that a passenger takes for reaching the final destination. The model takes into consideration that the profit is independent of the number of available seats (with a maximum determined for each airline). The method computes the optimal transfer pricing and, at the same time, optimizes the quantity of seats (the booking limits). The solution results in a strong Nash equilibrium, which incorporate both the transfer prices and booking limits. We describe the transfer pricing process using an ergodic, finite and continuous-time Markov game model for multiple players. The revenue of each airline in the supply chain will depend on the number of flight transfers and the transit time of the passenger at the airports: the longer the time to the final destination, the lower the price. We compute a collaborative equilibrium point, useful for understanding the resulting revenue of each member of the network. For solving the game, we employ an iterative method based on a proximal approach that involves time penalization. In our final contribution, we present results from a numerical example, which validates the proposed Markov game model and measures the benefits of the transfer pricing resource allocation.〈/p〉 〈/div〉

Description: 〈p〉Publication date: Available online 12 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Journal of Operational Research〈/p〉 〈p〉Author(s): Valentin Zelenyuk〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The main goal of this paper is to explore the possible solutions to a ‘big data’ problem related to the very large dimensions of input–output data. In particular, we focus on the cases of severe ‘curse of dimensionality’ problem that require dimension-reduction prior to using Data Envelopment Analysis. To achieve this goal, we have presented some theoretical grounds and performed a new to the literature simulation study where we explored the price-based aggregation as a solution to address the problem of very large dimensions.〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 12 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Journal of Operational Research〈/p〉 〈p〉Author(s): M. Densing〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A stored commodity is sold under a capacity constraint depending on an exogenous random market price, and, alternatively, a service contract can be provided in which the selling amount must be held constant over time independent of price changes. The seller of the commodity is assumed to optimize the trade-off between the received payment for the provision of the service and the loss of flexibility by the reduced selling on the market. The chosen setup allows for closed-form solutions, such that the analysis is of theoretical interest. A potential application is hydropower storage optimization against exogenous electricity prices with the option to enter contracts for providing spinning reserve; spinning reserve is needed to stabilize large-scale power systems. A single-period model is considered, and the storage level of the commodity is bounded from below in expectation. These simplifications allow a closed-form solution of bang-bang type, even under our assumption of an infinite probability space.〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 8 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Journal of Operational Research〈/p〉 〈p〉Author(s): Landir Saviniec, Maristela O. Santos, Alysson M. Costa, Lana M.R. dos Santos〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉High school timetabling problems consist in building periodic timetables for class-teacher meetings considering compulsory and non-compulsory requirements. This family of problems has been widely studied since the 1950s, mostly via mixed-integer programming and metaheuristic techniques. However, the efficient search of optimal or near-optimal solutions is still a challenge for many problems of practical size. In this paper, we investigate mixed-integer programming formulations and a parallel metaheuristic based algorithm for solving high school timetabling problems with compactness and balancing requirements. We propose two pattern-based formulations and a solution algorithm that simultaneously exploits column generation and a team of metaheuristics to build and improve solutions. Extensive computational experiments conducted with real-world instances demonstrate that our formulations are competitive with the best existing high school timetabling formulations, while our parallel algorithm presents superior performance to alternative methods available in the literature.〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 5 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Journal of Operational Research〈/p〉 〈p〉Author(s): Kai A. Konrad〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This paper studies the attack-and-defence game between a web user and a whole set of players over this user’s ‘valuable secrets.’ The number and type of these valuable secrets are the user’s private information. Attempts to tap information as well as privacy protection are costly. The multiplicity of secrets is of strategic value for the holders of these secrets. Users with few secrets keep their secrets private with some probability, even though they do not protect them. Users with many secrets protect their secrets at a cost that is smaller than the value of the secrets protected. The analysis also accounts for multiple redundant information channels with cost asymmetries, relating the analysis to attack-and-defence games with a weakest link.〈/p〉〈/div〉

Description: 〈p〉Publication date: December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Computers & Operations Research, Volume 112〈/p〉 〈p〉Author(s): Johannes Tiwisina, Philipp Külpmann〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉We seek to find the statistical model that most accurately describes empirically observed results in sports. This model has only two assumptions: a trinomial distribution of outcomes and a transitive relationship between these probabilities. The latter is implemented by imposing constraints on the outcome probabilities. To find the most likely correct ranking, we propose a Branch-and-Bound algorithm and a quicker, heuristic method.〈/p〉 〈p〉We apply the model to panel data from soccer, American football and tennis. Due to the transitivity assumption, our model has a natural application in comparing ranking systems. Therefore, we use it to evaluate empirically applied ranking schemes.〈/p〉 〈/div〉

Description: 〈p〉Publication date: Available online 3 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Omega〈/p〉 〈p〉Author(s): Claudia Caballini, Massimo Paolucci〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The evolving safety regulation is pushing seaports to comply with safety measures for workers performing heavy loads handling and repetitive movements. This paper proposes a risk-aware rostering approach in maritime container terminals, i.e., it addresses the rostering problem of minimizing and balancing workers’ risk in such terminals. To this end, a mixed integer mathematical programming model incorporating workforce risks is proposed, considering constraints such as the satisfaction of the workforce demand to perform the terminal operations, the worker-task compatibility and restrictions on the sequence of tasks assigned to the same worker. The model has been successfully applied to plan workforce over a six months horizon in a real container terminal located in Northern Italy, the Southern European Container Hub (SECH) in Genoa. As the workforce demand in SECH terminal is available at most two weeks in advance, a rolling horizon planning approach is devised. Experimental tests on real data provided by SECH terminal over a six months planning horizon highlight the effectiveness of the approach - the maximum monthly risk for workers is reduced by 33.9% compared to the current planning – and suitability to other container terminal contexts. Moreover, the model is applicable to a broad range of port situations, and robust enough to need little adaptation.〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 3 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Omega〈/p〉 〈p〉Author(s): Ruiyue Lin, Zongxin Li〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Current data envelopment analysis (DEA) models with diversification cannot discriminate the performance of efficient mutual funds. Based on the directional distance function and diversification DEA models, this paper proposes two diversification super-efficiency models for discriminating the performance of efficient mutual funds on financial market. The proposed diversification super-efficiency models as well as the corresponding diversification DEA models are feasible and can deal with negative values in risk measures, transaction costs and return measures. The proposed methods generate bounded super-efficiency scores for all the funds. Under the assumption of discrete return distributions, all the models in the proposed diversification super-efficiency methods can be transformed into linear programming (LP) problems by choosing proper risk and return measures. To demonstrate the validity and practicality of the proposed diversification super-efficiency methods, we apply them to evaluate the performance of mutual funds in the American market. The empirical results show that the proposed diversification super-efficiency models can distinguish efficient funds well and the linear combination of efficient funds might be inefficient. Moreover, the backtesting results show that the proposed diversification super-efficiency models generally have a good practice value for the actual portfolio selection.〈/p〉〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Transportation Research Part B: Methodological, Volume 128〈/p〉 〈p〉Author(s): Da Xu, Xiaolei Guo, Guoqing Zhang〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉We study the optimal single-step coarse toll design problem for the bottleneck model where the toll level and tolling duration have maximum acceptable upper bounds and the unconstrained optimal solution exceeds the upper bounds. We consider proportional user heterogeneity where users’ values of time and schedule delay vary in fixed proportions. Three classic coarse tolling models are studied, the ADL, Laih and braking models. In the ADL model, untolled users form a mass arrival at the bottleneck following the last tolled user. In the Laih model, there is a separated waiting facility for untolled users to wait until the toll ends. In the braking model, untolled users can choose to defer their arrival at the bottleneck to avoid paying the toll. We find that, in the ADL and the Laih models, the optimal solution chooses the maximum acceptable toll level and tolling duration. The ADL model further requires the tolling period to be started as late as possible to eliminate the queue at the toll ending moment. In the braking model, if the upper bound of the tolling duration is too small, no toll should be charged. Otherwise the optimal solution chooses the maximum acceptable tolling duration and may choose a toll price less than the maximum acceptable level.〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 2 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Journal of Operational Research〈/p〉 〈p〉Author(s): C. Archetti, D. Feillet, A. Mor, M.G. Speranza〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The dynamic traveling salesman problem with stochastic release dates (DTSP-srd) is a problem in which a supplier has to deliver parcels to its customers. These parcels are delivered to its depot while the distribution is taking place. The arrival time of a parcel to the depot is called its release date. In the DTSP-srd, release dates are stochastic and dynamically updated as the distribution takes place. The objective of the problem is the minimization of the total time needed to serve all customers, given by the sum of the traveling time and the waiting time at the depot. The problem is represented as a Markov Decision Process and is solved through a reoptimization approach. Two models are proposed for the problem to be solved at each stage. The first model is stochastic and exploits the entire probabilistic information available for the release dates. The second model is deterministic and uses an estimation of the release dates. An instance generation procedure is proposed to simulate the evolution of the information to perform computational tests. The results show that a more frequent reoptimization provides better results across all tested instances and that the stochastic model performs better than the deterministic model. The main drawback of the stochastic model lies in the computational time required to evaluate a solution, which makes an iteration of the heuristic substantially more time-consuming than in the case where the deterministic model is used.〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 2 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Production Economics〈/p〉 〈p〉Author(s): Xinfang (Jocelyn) Wang, Jomon A. Paul〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This paper applies the concept of social cost (i.e., logistic, deprivation, and fatality costs) to analyze the optimal deployment time, location and capacities of stockpiles for Points of Distribution (PODs) in hurricane preparedness. We first propose a single-stage, adaptive robust model to determine the optimal deployment time, given the time-variant characteristics of hurricanes. The model is nested in an optimal stopping-time framework that captures the trade-offs between increasing deployment costs and reduced uncertainty as the hurricane approaches landfall. Once the optimal deployment time has been determined, we then propose a less conservative, two-stage robust optimization model with recourse actions to determine the PODs’ location, stockpile capacities and flow. Tested on a case study, results show that 1) a non-adaptive model leads to poor decisions about the optimal deployment time; 2) improperly modeled deprivation costs pose significant hidden risks to decisionmakers; 3) deprivation costs increase $3–5 for every dollar cut when the available budget is strictly binding; and 4) significant savings in social cost result from the wait-and-see strategy implemented through the two-stage robust model.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Energy Economics, Volume 83〈/p〉 〈p〉Author(s): Claudiu Tiberiu Albulescu, Riza Demirer, Ibrahim D. Raheem, Aviral Kumar Tiwari〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉We provide novel insight to the emerging literature on the role of U.S. monetary policy as a driver of a global financial cycle by examining the possible causal effect of U.S. economic policy uncertainty on the connectedness of crude oil and currency markets, using a sample of commodity currencies from advanced and emerging nations. A battery of linear and nonlinear Granger-based causality tests indicate the presence of a causal relationship between economic policy uncertainty and the connectedness of oil and currency markets, particularly at low frequencies and more significantly after the outburst of the global financial crisis. While crude oil generally serves as a net transmitter of shocks to currencies across all frequency bands, the spillover effects from oil are largely concentrated towards the G10 currencies of Australian and New Zealand dollar that are often used as investment currencies in global carry trade strategies. Overall, our findings suggest the presence of a significant pass-through effect of economic policy uncertainty via oil prices, spilling over to the currency market, in line with the emerging evidence that the monetary policy by the U.S. Fed serves as a major driver of a global financial cycle that describes patterns in global capital flows, credit activity and asset prices across financial markets.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Geoforum, Volume 106〈/p〉 〈p〉Author(s): Yolanda Ariadne Collins〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this paper, I argue that the Reducing Emissions from Deforestation and forest Degradation (REDD+) mechanism, a globally driven, market-based environmental policy, is racialized in practice. Yet, consideration of how the uptake of these policies is challenged by racialized relations is insufficiently addressed in the neoliberal conservation literature. Colonial histories are sedimented in racialized subjectivities and land management practices where certain economic activities, geographical sites and interactions with the natural environment became the stronghold of different groups. In this paper, I demonstrate how the Reducing Emissions from Deforestation and forest Degradation (REDD+) mechanism, one such globally driven, market-based environmental policy, is challenged by the legacy of these racialized land use practices and social relations rooted in the defining colonial period in Guyana and Suriname. I outline the relationship between the processes of politically demarcating forests and of shaping subjectivities, drawing attention to how these processes are impacted by REDD+. Through a focus on gold mining, explored here as a historically conditioned, economic relationship with the natural environment, I show how REDD+ contributes to state territorialisation, complicates pre-existing racialized subjectivities and increases the legibility of forests and their amenability to state management.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Geoforum, Volume 106〈/p〉 〈p〉Author(s): Aisa O. Manlosa, Jannik Schultner, Ine Dorresteijn, Joern Fischer〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉We investigated how smallholder farming households in southwestern Ethiopia coped with challenges related to lack in capital assets and food shortage. We focused on interactions between capital assets using, in particular, capital asset substitution as an analytical lens to classify and unpack the interactions. The most commonly mentioned challenges were related to natural and economic capitals, and these frequently caused seasonal food shortages. Households responded to the lack in capital assets or food through processes that drew on more readily available capital assets. Common ways in which households coped involved drawing on social and human capitals (i.e. increasing labor input) to address lack in other types of capital assets and lack in food. These types of asset substitution tended to facilitate the maintenance of a household’s capital asset base. In contrast, some households liquidated physical and economic capital assets to cope, but these types of substitution tended to erode their capital asset base. In sum, our findings highlight the natural environment as well as social and human capitals as foundational to smallholder livelihoods and food security. In practical terms, the study provides information on coping strategies that should be avoided or modified to prevent capital asset erosion, and highlights those that should be supported and strengthened to enable the maintenance (and eventual growth) of households’ capital assets. Conceptually, the study contributes to livelihoods research by highlighting the usefulness of capital asset substitution for investigating interactions between different capital assets.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 28 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Journal of Operational Research〈/p〉 〈p〉Author(s): María Isabel Hartillo-Hermoso, Haydee Jiménez-Tafur, José María Ucha-Enríquez〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A new exact algorithm for bi-objective linear integer problems is presented, based on the classic ϵ-constraint method and algebraic test sets for single-objective linear integer problems. Our method provides the complete Pareto frontier 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si19.svg"〉〈mi mathvariant="bold-script"〉N〈/mi〉〈/math〉 of non-dominated points and, for this purpose, it considers exactly 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si5.svg"〉〈mrow〉〈mo〉|〈/mo〉〈mi mathvariant="bold-script"〉N〈/mi〉〈mo〉|〈/mo〉〈/mrow〉〈/math〉 single-objective problems by using reduction with test sets instead of solving with an optimizer. Although we use Gröbner bases for the computation of test sets, which may provoke a bottleneck in principle, the computational results are shown to be promising, especially for unbounded knapsack problems, for which any usual branch-and-cut strategy could be much more expensive. Nevertheless, this algorithm can be considered as a potentially faster alternative to IP-based methods when test sets are available.〈/p〉〈/div〉