ALBERT

Description: The use of multiple-input multiple-output (MIMO) communication systems has attracted considerable attention due to capacity and performance improvements without increasing the required bandwidth or transmission power. Although MIMO improves the transmission rate and provides reliable communication, these advantages come at a high cost, since multiple radio frequency (RF) chains have to be employed. Therefore, cost-effective implementation of MIMO systems remains as an important challenge. In this sense, antenna selection techniques (AST) can help reduce the high cost of MIMO systems, while retaining most of their benefits; and in order to improve channel capacity, transmission power can be allocated efficiently according to the channel experienced by each antenna element. In this paper, we show the channel capacity improvement of MIMO systems, by combining the use of AST and transmission power allocation through the water-pouring algorithm (WPA) for different antenna configurations. We apply WPA and allocate more power to the channel with better conditions, when the MIMO channel is Rayleigh distributed and noise is Gaussian. By employing these two techniques (AST and WPA), we show that channel capacity is significantly improved, with higher capacity values than those obtained using traditional systems which just spread equal power among all the transmit antennas. We also show that bounds on the capacity can be considered when these improvements are used in a MIMO system.

Description: Vehicular ad hoc networks are a long-term solution contributing significantly towards intelligent transport systems (ITS) in providing access to critical life-safety applications and services. Although vehicular ad hoc networks are attracting greater commercial interest, current research has not adequately captured the real-world constraints in vehicular ad hoc network handover techniques. Therefore, in order to have the best practice for vehicular ad hoc network services, it is necessary to have seamless connectivity for optimal coverage and ideal channel utilisation. Due to the high velocity of vehicles and smaller coverage distances, there are serious challenges in providing seamless handover from one roadside unit (RSU) to another. Though other research efforts have looked at many issues in vehicular ad hoc networks (VANETs), very few research work have looked at handover issues. Most literature assume that handover does not take a significant time and does not affect the overall VANET operation. In our previous work, we started to investigate these issues. This journal provides a more comprehensive analysis involving the beacon frequency, the size of beacon and the velocity of the vehicle. We used some of the concepts of Y-Comm architecture such as network dwell time (NDT), time before handover (TBH) and exit time (ET) to provide a framework to investigate handover issues. Further simulation studies were used to investigate the relation between beaconing, velocity and the network dwell time. Our results show that there is a need to understand the cumulative effect of beaconing in addition to the probability of successful reception as well as how these probability distributions are affected by the velocity of the vehicle. This provides more insight into how to support life critical applications using proactive handover techniques.

Description: We study the following separation problem: given \(n\) connected curves and two points \(s\) and \(t\) in the plane, compute the minimum number of curves one needs to retain so that any path connecting \(s\) to \(t\) intersects some of the retained curves. We give the first polynomial \((\fancyscript{O}(n^3))\) time algorithm for the problem, assuming that the curves have reasonable computational properties. The algorithm is based on considering the intersection graph of the curves, defining an appropriate family of closed walks in the intersection graph that satisfies the 3-path-condition, and arguing that a shortest cycle in the family gives an optimal solution. The 3-path-condition has been used mainly in topological graph theory, and thus its use here makes the connection to topology clear. We also show that the generalized version, where several input points are to be separated, is NP-hard for natural families of curves, like segments in two directions or unit circles.

Description: This study extends previous literature on the association between Confucianism and corporate decisions by examining Confucianism’s influence on board gender diversity. Using a sample of Chinese listed firms during the period of 2001–2011 and geographic-proximity-based Confucianism variables, I provide strong and consistent evidence to show that Confucianism is significantly negatively associated with board gender diversity, suggesting that the proportion of women directors in the boardroom is significantly lower for firms surrounded by strong Confucianism atmosphere than for firms located in regions with weak Confucianism atmosphere. This finding also implies that Confucian philosophical system has important impacts on business ethics and women’s status in corporate governance. Moreover, GDP per capita, the proxy for economic development level in a province in which a firm is located, attenuates the negative association between Confucianism and board gender diversity. Above results are robust to different measures of Confucianism and board gender diversity and are still valid after controlling for the potential endogeneity between Confucianism and board gender diversity.

Description: Globalization is multifaceted and involves the interaction among businesses, services, governments, and societies beyond national borders. As a result, the flow of foreign direct investment (FDI), international trade in goods and services, and the economic interdependence of the nations of the world have been increasing. At the same time, much attention has been paid to the effect of corruption prevalent within many cultures and societies, and its impact on the economies, especially developing economies. This paper examines the relationship between human capital investment, the level of national corruption, and the global economic integration (GEI) of a nation in developing countries. Based on the data collected from over 60 countries, and building on the FDI and human capital theories, it was found that human capital investment and corruption are related to GEI. It was also found that the level of corruption moderates the relationship between human capital investment and GEI of developing economies. The findings of the study can help to deepen our understanding of GEI and have practical implications for developing countries in terms developing human capital, which plays a critical role in today’s knowledge-based economy.

Description: Monitoring is an important aspect of designing and maintaining large-scale systems. Cloud computing presents a unique set of challenges to monitoring including: on-demand infrastructure, unprecedented scalability, rapid elasticity and performance uncertainty. There are a wide range of monitoring tools originating from cluster and high-performance computing, grid computing and enterprise computing, as well as a series of newer bespoke tools, which have been designed exclusively for cloud monitoring. These tools express a number of common elements and designs, which address the demands of cloud monitoring to various degrees. This paper performs an exhaustive survey of contemporary monitoring tools from which we derive a taxonomy, which examines how effectively existing tools and designs meet the challenges of cloud monitoring. We conclude by examining the socio-technical aspects of monitoring, and investigate the engineering challenges and practices behind implementing monitoring strategies for cloud computing.

Description: No abstract