ALBERT

Beschreibung: In cognitive radio networks, the secondary users (SUs) switch the data transmission to another empty spectrum band to give priority to primary users (PUs). In this paper, channel switching in cognitive radio mobile ad hoc networks (CR-MANETs) through an established route is modeled. The probability of channel availability in this route is calculated based on the PU's activity, SU's mobility, and channel heterogeneity. Based on the proposed model, the channel and link availability time are predicted. These predictions are used for channel assignment in the proposed channel allocation scheme. A handoff threshold as well as a life time threshold is used in order to reduce the handoff delay and the number of channel handoffs originating from the short channel usage time. When the channel handoff cannot be done due to the SU's mobility, the local flow handoff is performed to find an appropriate node in the vicinity of a potential link breakage and transfer the current data flow to it. The local flow handoff is performed to avoid possible flow disruption and also to reduce the delay caused by the link breakage. The study reveals that the channel heterogeneity and SU's mobility must be considered as important factors, which affect the performance of the handoff management in the CR-MANETs. The results emphasize on the improvement of the route maintenance probability after using the local flow handoff. It is also stated that the amounts of handoff requirement and handoff delay are decreased after using the predicted channel usage life time and handoff threshold time.

Beschreibung: In this study, a porous inserted regenerative thermal oxidizer (PRTO) system was developed for a 125 kW industrial copper-melting furnace, due to its advantages of low NO x emissions and high radiant efficiency. Zirconium dioxide (ZrO 2 ) ceramic foams were placed into the combustion zone of a regenerative thermal oxidizer (RTO). Different performance characteristics of the RTO and PRTO systems, including pressure drop, temperature distribution, emissions, and energy efficiency, were evaluated to study the effects of the porous inserts on non-premixed CH 4 combustion. It was found that the PRTO system achieved a significant reduction in the NO x emission level and a fuel saving of approximately 30% compared to the RTO system. It is most suitable for a lean combustion process at an equivalence ratio 〈0.4 with NO x and CO emission levels within 0.002%–0.003% and 0.001%–0.002%, respectively.

Beschreibung: This paper presented a control design methodology for a proton exchange membrane fuel cell (PEMFC) generation system for residential applications. The dynamic behavior of the generation system is complex in such applications. A comprehensive control design is very important for achieving a steady system operation and efficiency. The control strategy for a 60 kW generation system was proposed and tested based on the system dynamic model. A two-variable single neuron proportional-integral (PI) decoupling controller was developed for anode pressure and humidity by adjusting the hydrogen flow and water injection. A similar controller was developed for cathode pressure and humidity by adjusting the exhaust flow and water injection. The desired oxygen excess ratio was kept by a feedback controller based on the load current. An optimal seeking controller was used to trace the unique optimal power point. Two negative feedback controllers were used to provide AC power and a suitable voltage for residential loads by a power conditioning unit. Control simulation tests showed that 60 kW PEMFC generation system responded well for computer-simulated step changes in the load power demand. This control methodology for a 60 kW PEMFC generation system would be a competitive solution for system level designs such as parameter design, performance analysis, and online optimization.

Beschreibung: With the continuous improvement of the train speed, the dynamic environment of trains turns out to be aerodynamic domination. Solving the aerodynamic problems has become one of the key factors of the high-speed train head design. Given that the aerodynamic drag is a significant factor that restrains train speed and energy conservation, reducing the aerodynamic drag is thus an important consideration of the high-speed train head design. However, the reduction of the aerodynamic drag may increase other aerodynamic forces (moments), possibly deteriorating the operational safety of the train. The multi-objective optimization design method of the high-speed train head was proposed in this paper, and the aerodynamic drag and load reduction factor were set to be optimization objectives. The automatic multi-objective optimization design of the high-speed train head can be achieved by integrating a series of procedures into the multi-objective optimization algorithm, such as the establishment of 3D parametric model, the aerodynamic mesh generation, the calculation of the flow field around the train, and the vehicle system dynamics. The correlation between the optimization objectives and optimization variables was analyzed to obtain the most important optimization variables, and a further analysis of the nonlinear relationship between the key optimization variables and the optimization objectives was obtained. After optimization, the aerodynamic drag of optimized train was reduced by up to 4.15%, and the load reduction factor was reduced by up to 1.72%.

Beschreibung: Structural health monitoring (SHM) is a relevant topic for civil systems and involves the monitoring, data processing and interpretation to evaluate the condition of a structure, in order to detect damage. In real structures, two or more sites or types of damage can be present at the same time. It has been shown that one kind of damaged condition can interfere with the detection of another kind of damage, leading to an incorrect assessment about the structure condition. Identifying combined damage on structures still represents a challenge for condition monitoring, because the reliable identification of a combined damaged condition is a difficult task. Thus, this work presents a fusion of methodologies, where a single wavelet-packet and the empirical mode decomposition (EMD) method are combined with artificial neural networks (ANNs) for the automated and online identification-location of single or multiple-combined damage in a scaled model of a five-bay truss-type structure. Results showed that the proposed methodology is very efficient and reliable for identifying and locating the three kinds of damage, as well as their combinations. Therefore, this methodology could be applied to detection-location of damage in real truss-type structures, which would help to improve the characteristics and life span of real structures.

Beschreibung: Due to interference between co-located wireless networks, obtaining accurate channel assessment becomesincreasingly important for wireless network configuration. This information is used, amongothers, for cognitive radio solutions and for intelligent channel selection in wireless networks. Solutionssuch as spectrum analyzers are capable of scanning a wide spectrum range, but are not dedicatedfor channel occupation assessment because they are extremely costly and not able to perform continuousrecording for a time period longer than a few seconds. On the other hand, low-cost solutionslack the flexibility and required performance in terms of configuration and sensing efficiency. To remedythe situation, this paper presents an alternative for channel assessment on top of a commercialsoftware-defined radio platform. Although there exist software solutions for performing spectrumsensing on such platforms, to the best of our knowledge, continuous spectrum sensing and long-termrecording remain challenging. We propose a pioneering solution that is capable of seamless spectrumsensing over a wide spectrum band and guarantees sufficient flexibility in terms of configurations. Theproposed solution is validated experimentally. We demonstrate two advantages of seamless spectrumsensing: the capability of accurate channel occupancy measurement and detecting transient signalssuch as Bluetooth.

Beschreibung: Long-term monitoring of an environment is a fundamental requirement for most wireless sensornetworks. Owing to the fact that the sensor nodes have limited energy budget, prolonging theirlifetime is essential in order to permit long-term monitoring. Furthermore, many applications requiresensor nodes to obtain an accurate estimation of a point-source signal (for example, an animal call orseismic activity). Commonly, multiple sensor nodes simultaneously sample and then cooperate toestimate the event signal. The selection of cooperation nodes is important to reduce the estimationerror while conserving the network's energy. In this paper, we present a novel method for sensor dataacquisition and signal estimation, which considers estimation accuracy, energy conservation, andenergy balance. The method, using a concept of 'virtual clusters,' forms groups of sensor nodes withthe same spatial and temporal properties. Two algorithms are used to provide functionality. The'distributed formation' algorithm automatically forms and classifies the virtual clusters. The 'roundrobin sample scheme' schedules the virtual clusters to sample the event signals in turn. Theestimation error and the energy consumption of the method, when used with a generalized sensingmodel, are evaluated through analysis and simulation. The results show that this method can achievean improved signal estimation while reducing and balancing energy consumption.

Beschreibung: We study the problem of achieving maximum network throughput with fairness among the flows at the nodes in a wireless mesh network, given their location and the number of their half-duplex radio interfaces. Our goal is to find the minimum number of non-overlapping frequency channels required to achieve interference-free communication. We use our existing Select x for less than x topology control algorithm (TCA) to build the connectivity graph (CG), which enhances spatial channel reuse to help minimize the number of channels required. We show that the TCA-based CG approach requires fewer channels than the classical approach of building the CG based on the maximum power. We use multi-path routing to achieve the maximum network throughput and show that it provides better network throughput than the classical minimum power-based shortest path routing. We also develop an effective heuristic method to determine the minimum number of channels required for interference-free channel assignment.

Beschreibung: Excessive depth perception in 3D video is one of the major factors that causes discomfort to the viewer and that can decrease the viewer's quality perception of 3D video. With the idea of real-time quality control of 3D videos, we proposed an edge-based sparse disparity estimation algorithm with a novel similarity metric. The comparative assessment with other four state-of-the-art similarity metrics, implemented within the proposed edge-based disparity estimator, showed higher performance for the novel metric. User tests are conducted to assess the relation between certain disparity statistics and user perception of 3D scene quality that is a retrospective subjective experience of quality. Subjective tests indicate that the viewer discomfort can be predicted best by using maximum and slew rate of 95 percentile scene disparities together.

Beschreibung: It is a difficult job to gauge the liquid fuel mass in a tank on spacecrafts under microgravity condition. Without the presence of strong buoyancy, the configuration of the liquid and gas in the tank is uncertain and more than one bubble may exist in the liquid part. All these will affect the measure accuracy of liquid mass gauge, especially for a method called Compression Mass Gauge (CMG). Four resonance resources affect the choice of compression frequency for CMG method. There are the structure resonance, liquid sloshing, transducer resonance and bubble resonance. Ground experimental apparatus are designed and built to validate the gauging method and the influence of different compression frequencies at different fill levels on the measurement accuracy. Harmonic phenomenon should be considered during filter design when processing test data. Results demonstrate the ground experiment system performances well with high accuracy and the measurement accuracy increases as the compression frequency climbs in low fill levels. But low compression frequencies should be the better choice for high fill levels. Liquid sloshing induces the measurement accuracy to degrade when the surface is excited to wave by external disturbance at the liquid natural frequency. The measurement accuracy is still acceptable at small amplitude vibration.

Beschreibung: In this paper, we address the issue of collaborative information processing for diffusive source localization and tracking using wireless sensor networks capable of sensing in dispersive medium/environment. We first determine the space-time concentration distribution of the dispersion from physical modeling and mathematical formulations of an underwater oil spill scenario, considering the effect of laminar water velocity as an external force. For static diffusive source localization, we propose two parametric estimation techniques based on maximum-likelihood (ML) and best linear unbiased estimator for the special case of our physical dispersion model. We prove the consistency and asymptotic normality of the obtained ML solution when the number of sensor nodes and samples approach infinity, and derive the Cramér-Rao lower bound on its performance. We also propose a particle filter-based target tracking scheme for moving diffusive source and derive the posterior Cramér-Rao lower bound for the moving source state estimates as a theoretical performance bound. The performance of the proposed schemes are shown through numerical simulations and compared with the derived theoretical bounds.

Beschreibung: Radio frequency identification (RFID) is a promising wireless technology for using tiny, remotely powered chips as identifiers. The number of RFID applications is rapidly increasing because RFID technology is convenient, fast, and contactless. However, collisions occur when multiple tags simultaneously transmit their IDs. Therefore, an efficient anti-collision algorithm is needed to accelerate tag identification. In some applications, the reader may repeatedly identify staying tags, which constantly exist in the reader's range. The adaptive query splitting algorithm (AQS) was proposed for reserving information obtained from the last identification process to enable rapid re-identification of staying tags. However, since AQS is a non-blocking algorithm that allows newly arriving tags to use the slots reserved for staying tags, collisions among them are problematic. Thus, semi-blocking AQS (SBA) proposed in this study is designed to reduce the collisions between arriving tags and staying tags by applying a semi-blocking technique in which only a minority of arriving tags use the slots reserved for staying tags. By counting the number of minor arriving tags, SBA estimates the number of unrecognized arriving tags and generates proper queries to minimize their collisions. The identification delay of SBA is analyzed, and simulation results show that SBA significantly outperforms AQS.

Beschreibung: Linear stability of plane-parallel pulsational flow of two miscible fluids in a horizontal layer subjected to high frequency horizontal vibrations is investigated neglecting viscosity and diffusion. Long-wave instability is studied analytically and instability to the perturbations with finite wavelength—numerically.

Beschreibung: Using the impulse responses of these multipath channels, the bit error rate (BER) performance for binary pulse amplitude modulation impulse radio ultra-wideband communication system is calculated. The optimization location of receiving antenna is investigated by dynamic differential evolution (DDE) and genetic algorithm (GA) to minimize the outage probability. Numerical results show that the performance for reducing BER and outage probability by DDE algorithm is better than that by GA.

Beschreibung: For unmanned air vehicles (UAVs) to survive hostile operational environments, it is always preferableto utilize all wireless positioning sources available to fuse a robust position. While belief propagationis a well-established method for all source data fusion, it is not an easy job to handle all themathematics therein. In this work, a comprehensive mathematical framework for belief propagationbasedall-source positioning of UAVs is developed, taking wireless sources including GlobalNavigation Satellite Systems (GNSS) space vehicles, peer UAVs, ground control stations, and signalof opportunities. Based on the mathematical framework, a positioning algorithm named Beliefpropagation-based Opportunistic Positioning of UAVs (BOPU) is proposed, with an unscented particlefilter for Bayesian approximation. The robustness of the proposed BOPU is evaluated by a fictitiousscenario that a group of formation flying UAVs encounter GNSS countermeasures en route. Fourdifferent configurations of measurements availability are simulated. The results show that theperformance of BOPU varies only slightly with different measurements availability.

Beschreibung: One of the key problems in distributed video coding is the generation of the side information. This task consists of producing an estimation of an image given some neighboring ones, such as those taken by the same camera at different time instants, or, in the case of multiview setups, images taken at the same time instant by different cameras. If both estimations are available, a further problem arises, that is how to merge them in order to create a single side information. This problem is very relevant since a good estimation of the unknown image will require only a few bits to be corrected. Considering a multiview distributed video coding setup, we propose a novel technique for inter-view interpolation based on an occlusion prediction, a new fusion technique based on occlusion detection, and finally an adaptive validation step for switching among the three possible side information images: temporal, inter-view and fusion.We provide a comprehensive set of experimental results, which indicate bit-rate reductions of more than 9 % in the average; moreover, we observe much more consistent results with respect to state-of-the-art techniques.

Beschreibung: The collision frequency function for aerosol particles has already been calculated for the free molecule regime and for the continuum range. The present work, taking into account the influence of internal force fields such as magnetic force, electric force and molecular forces, created by particles themselves, recalculated the collision frequency in the case of particles much smaller than the mean free path of the gas (free molecule regime). Attractive forces increase naturally the collision frequency, while repulsive forces decrease it. The calculation was performed for all types of central forces deriving from a potential, including Coulomb forces and Van der Waals forces.

Beschreibung: As the basis of modern industry, the roles materials play are becoming increasingly vital in this day and age. With many superior physical properties over conventional fluids, the low melting point liquid metal material, especially room-temperature liquid metal, is recently found to be uniquely useful in a wide variety of emerging areas from energy, electronics to medical sciences. However, with the coming enormous utilization of such materials, serious issues also arise which urgently need to be addressed. A biggest concern to impede the large scale application of room-temperature liquid metal technologies is that there is currently a strong shortage of the materials and species available to meet the tough requirements such as cost, melting point, electrical and thermal conductivity, etc. Inspired by the Material Genome Initiative as issued in 2011 by the United States of America, a more specific and focused project initiative was proposed in this paper—the liquid metal material genome aimed to discover advanced new functional alloys with low melting point so as to fulfill various increasing needs. The basic schemes and road map for this new research program, which is expected to have a worldwide significance, were outlined. The theoretical strategies and experimental methods in the research and development of liquid metal material genome were introduced. Particularly, the calculation of phase diagram (CALPHAD) approach as a highly effective way for material design was discussed. Further, the first-principles (FP) calculation was suggested to combine with the statistical thermodynamics to calculate the thermodynamic functions so as to enrich the CALPHAD database of liquid metals. When the experimental data are too scarce to perform a regular treatment, the combination of FP calculation, cluster variation method (CVM) or molecular dynamics (MD), and CALPHAD, referred to as the mixed FP-CVMCALPHAD method can be a promising way to solve the problem. Except for the theoretical strategies, several parallel processing experimental methods were also analyzed, which can help improve the efficiency of finding new liquid metal materials and reducing the cost. The liquid metal material genome proposal as initiated in this paper will accelerate the process of finding and utilization of new functional materials.

Beschreibung: According to the ongoing IEEE 802.11ac amendment, the wireless network is about to embrace the gigabit-per-second raw data rate. Compared with previous IEEE standards, this significant performance improvement can be attributed to the novel physical and medium access control (MAC) features, such as multi-user multiple-input multiple-output transmissions, the frame aggregation, and the channel bonding. In this paper, we first briefly survey the main features of IEEE 802.11ac, and then, we evaluate these new features in a fully connected wireless mesh network using an analytic model and simulations. More specifically, the performance of the MAC scheme defined by IEEE 802.11ac, which employs the explicit compressed feedback (ECFB) mechanism for the channel sounding, is evaluated. In addition, we propose an extended request-to-send/clear-to-send scheme that integrates the ECFB operation to compare with the IEEE 802.11ac-defined one in saturated conditions. The comparison of the two MAC schemes is conducted through three spatial stream allocation algorithms. A simple but accurate analytical model is derived for the two MAC schemes, the results of which are validated with simulations. The observations of the results not only reveal the importance of spatial stream allocations but also provide insight into how the newly introduced features could affect the performance of IEEE 802.11ac-based wireless mesh networks.

Beschreibung: In this paper, we derive a performance comparison between two training-based schemes for multipleinputmultiple-output systems. The two schemes are the time-division multiplexing scheme and therecently proposed data-dependent superimposed pilot scheme. For both schemes, a closed-form expressionfor the bit error rate (BER) is provided. We also determine, for both schemes, the optimalallocation of power between the pilot and data that minimizes the BER.

Beschreibung: This article is a brief summary of my plenary talk at the World Biomaterials Congress in Chengdu, Sichuan, China, June 1–5, 2012. It highlights the trend to design and develop biomaterial implants and devices that are more compact and more efficient, as they “shrink” from the macro- to the micro- and down to the nano-scale.

Beschreibung: Im nationalen Forschungsprojekt „Multifunktionales Batteriespeichersystem (MBS)“ wurden offene Fragen bezüglich der technischen Umsetzbarkeit und der Wirtschaftlichkeit eines netzgekoppelten Batteriespeichersystems mit einer Vanadium-Redox-Flow-Batterie in Kombination mit den Erzeugungsanlagen Photovoltaik und Kleinwindkraft zur intelligenten Vermarktung von erneuerbarer Energie beantwortet (Sterrer et al., Multifunktionales Batteriespeichersystem – MBS-Endbericht. Industrielle Forschung im Rahmen der österreichischen Programmlinie Neue Energie 2020, 3. Ausschreibung, noch nicht veröffentlicht, 2013 ). Die technische Umsetzung und der Demonstrationsbetrieb einer Pilotanlage während zweier Jahre zeigten, dass das Batteriespeichersystem für eine intelligente Vermarktung von erneuerbarer Energie sowie zur Bereitstellung von Systemdienstleistungen zur Netzstabilisierung geeignet ist. Jedoch zeigte die Untersuchung von unterschiedlichen Vermarktungsstrategien für die Pilotanlage, eine Großspeicheranlage und gepoolte PV/Batteriespeicheranlagen sowie deren Erlösmöglichkeiten an den Energiehandels- und Regelenergiemärkten, dass für sämtliche untersuchten Einsatzstrategien in absehbarer Zeit keine positiven Deckungsbeiträge erwirtschaftet werden können. Wenn jedoch die angestrebten Batteriezielkosten von ca. 250 €/kWh bis zum Jahr 2030 erreicht werden, scheint eine zukünftige Umsetzung von Vanadium-Redox-Flow-Batterien, vor allem in Großanlagen (z. B. 10 MW, 100 MWh), für die Teilnahme am Regelenergiemarkt realistisch.

Beschreibung: Special Issue on "Advanced Distributed Wireless Communication Techniques - Theory and Practice"

Beschreibung: “Partial pressure” in humid air is a question very much concerned by scientists and no satisfactory answer has been found to date. This paper proposes a novel method to obtain the “partial pressures” of the water vapor and dry air in humid air. The results obtained by the proposed method are quite different from that obtained by Dalton’s partial pressure law. The fundamental behaviors of water vapor and dry air are studied in depth in wide pressure and temperature ranges. Semi-permeable membrane models are proposed and applied for both saturated and unsaturated humid air. “Improvement factors” are developed to quantitatively describe the magnitude of the interaction between dissimilar molecules. One discovery is that the “partial pressure” of the water vapor in saturated humid air equals P s , rather than ( f · P s ) which was formerly believed. The other is that the interaction between dissimilar molecules may be omitted when temperature is above “cutting-off temperature” for unsaturated humid air. This paper satisfactorily answers the quest of “partial pressures” in humid air from a new perspective.

Beschreibung: Query-by-Example Spoken Term Detection (QbE STD) aims at retrieving data from a speech data repository given an acoustic query containing the term of interest as input. Nowadays, it has been receiving much interest due to the high volume of information stored in audio or audiovisual format. QbE STD differs from Automatic speech recognition (ASR) and keyword spotting (KWS)/spoken term detection (STD) since ASR is interested in all the terms/words that appear in the speech signal and KWS/STD relies on a textual transcription of the search term to retrieve the speech data. This paper presents the systems submitted to the ALBAYZIN 2012 QbE STD evaluation held as a part of ALBAYZIN 2012 evaluation campaign within the context of the IberSPEECH 2012 Conferencea. The evaluation consists of retrieving the speech files that contain the input queries, indicating their start and end timestamps within the appropriate speech file. Evaluation is conducted on a Spanish spontaneous speech database containing a set of talks from MAVIR workshopsb, which amount at about 7 h of speech in total. We present the database metric systems submitted along with all results and some discussion. Four different research groups took part in the evaluation. Evaluation results show the difficulty of this task and the limited performance indicates there is still a lot of room for improvement. The best result is achieved by a dynamic time warping-based search over Gaussian posteriorgrams/posterior phoneme probabilities. This paper also compares the systems aiming at establishing the best technique dealing with that difficult task and looking for defining promising directions for this relatively novel task.

Beschreibung: Per-cell codebook-based limited feedback is highly desirable in coordinated multi-point (CoMP) systems owing to flexibility and compatibility. Except for the per-cell codeword indices, each user should feed back other information for the central unit to reconstruct global channel direction information (CDI) and estimate channel quality information (CQI) for downlink transmission. In this paper, we analyze the essential feedback information for per-cell codebook-based coherent CoMP systems. To show what should be fed back to estimate the CQI, we first derive a conservative CQI estimation to avoid the outage in transmission, which depends on the quantization accuracy and the norm of the global channel. We then analyze whether the per-cell small-scale fading channel norms are necessary to feed back in obtaining the global channel norm and reconstructing the global CDI. Next, we analyze whether the feedback of phase ambiguity (PA) is necessary. Both the analysis and simulation results show that the global channel norm should be fed back instead of the per-cell channel norms. The benefit of the PA feedback is evident only when the number of base stations is large and the number of antennas at each base station is small.

Beschreibung: In estimating emissions reductions brought about by renewables in China, much of existing research assumes that renewables displace coal power. In this paper, this assumption is challenged and the potential environmental effects of photovoltaic (PV) power in North-west China are reevaluated when the marginal generator actually being displaced is taken into account. The annual PV power generation in the North-west Grid is estimated, in this paper, to be as high as 17900GW·h in 2015, roughly equaling to the output of 1.5 nuclear power plants in the US today. The total associated emission reduction in 2015 will at most be 0.36 percent of SO 2 and 0.25 percent of NO x emissions from their 2010 levels in China. Further, PV power may render no emissions reduction at all if it displaces hydropower, which is often used to meet peak demand in the North-west Grid in China. These results imply that a more cost-effective area of focus in the short-term may be on desulfurization and denitrification technologies for coal plants.

Beschreibung: In this paper, we introduce a modified cellular particle filter (CPF) which we mapped on a graphics processing unit (GPU) architecture. We developed this filter adaptation using a state-of-the art CPF technique. Mapping this filter realization on a highly parallel architecture entailed a shift in the logical representation of the particles. In this process, the original two-dimensional organization is reordered as a one-dimensional ring topology. We proposed a proof-of-concept measurement on two models with an NVIDIA Fermi architecture GPU. This design achieved a 411-µs kernel time per state and a 77-ms global running time for all states for 16,384 particles with a 256 neighbourhood size on a sequence of 24 states for a bearing-only tracking model. For a commonly used benchmark model at the same configuration, we achieved a 266-µs kernel time per state and a 124-ms global running time for all 100 states. Kernel time includes random number generation on the GPU as well as with curand. These results attest to the effective and fast use of the particle filter in high-dimensional, real-time applications.

Beschreibung: Objective metrics for visual quality assessment often base their reliability on the explicit modeling of the highly non-linear behavior of human perception; as a result, they may be complex and computationally expensive. Conversely, machine learning (ML) paradigms allow to tackle the quality assessment task from a different perspective, as the eventual goal is to mimic quality perception instead of designing an explicit model the human visual system. Several studies already proved the ability of ML-based approaches to address visual quality assessment; nevertheless, these paradigms are highly prone to overfitting, and their overall reliability may be questionable. In fact, a prerequisite for successfully using ML in modeling perceptual mechanisms is a profound understanding of the advantages and limitations that characterize learning machines. This paper illustrates and exemplifies the good practices to be followed.

Beschreibung: As the geostationary orbit (GEO) is congested in the commercial Ku band, the adjacent satellites willreceive the interference from small aperture terminals which have a wide field of view. To reducethe interference toward the adjacent satellites, code division multiple access (CDMA) with spreadspectrum needs to be adopted in the satellite communications on-the-move system. However, themutual interference between CDMA users leads to the performance loss, which is not acceptable forthe power-sensitive small aperture terminals, and the computation complexity is still an intractableproblem when the conventional iterative minimum mean square error (MMSE) scheme is employedto suppress the multiple access interference (MAI) in satellite systems especially that is coded bylow-density parity-check (LDPC) code. Moreover, the long transmission delays of different userscaused by the long transmission distance require the robustness of the interference suppression forthe asynchronous case. In this paper, a joint chip-level algorithm for CDMA multiuser detectionand LDPC decoding with a new and simple iterative structure based on belief propagation (BP)for satellite systems is developed, which integrates the iterations of multiuser detection and theiterations of LDPC decoding with factor graphs. Through analysis and simulations, it is verified thatthe proposed algorithm is robust to the asynchronous CDMA satellite system, and with the similariterative complexity, the performance of the proposed algorithm outperforms that of the conventionaliterative MMSE scheme in the asynchronous CDMA satellite system.

Beschreibung: In this paper, we propose the use of bit-interleaved coded modulation in alternate-relaying decode-and-forward cooperative communication systems. At the destination, we exploit the interference signal, which results from the simultaneous transmission of data streams through both direct and one of the relay channels to develop an optimal detector. It is shown that the proposed detector can be implemented by parallel concatenating maximum \textit{a posteriori} (MAP) algorithms and demappers to the decoders. The detector exchanges soft information between the decoders and the MAP algorithms in an iterative way for performance improvement. The proposed optimal detector requires a long delay as the destination has to receive and store the entire frame before performing data detection. To avoid this, a sub-optimal detector is also proposed. Unlike the optimal detector, the sub-optimal one exploits two consecutive received packets to decode one packet. It turns out that the sub-optimal detector has less reduced delay, complexity, memory size, and bandwidth loss with a slight increase of the bit-error-rate. Extensive simulation results are presented to demonstrate the effectiveness of the proposed detectors.

Beschreibung: Opportunistic routing (OR) protocols for ad hoc networks basically consist of selecting a few forwardersbetween the source and destination and prioritizing their transmission. The performance ofOR protocols depends on how these two steps are performed. The aim was to reduce the numberof transmissions to deliver packets to the destination. In this paper, we first present a mathematicalmodel to compute the total number of packets including duplicate packets generated by OR protocols.We use the model to analyse well-known OR protocols and understand the reason behind theirincrease in number of transmissions. Next, we propose an OR scheme transmission-aware opportunisticad hoc routing (TOAR) protocol, which attempts to minimize retransmissions. Our proposedOR protocol uses tree structures to select forwarders and prioritize them. The use of tree structureshelps in identifying primary forwarders which carry packets farthest to the destination during eachtransmission round. TOAR also helps in choosing secondary forwarders which will transmit packetsmissed out by the forwarder. The optimized selection of forwarders results in significant reduction inretransmissions, a smaller forwarder list set, and improvement in goodput.

Beschreibung: This contribution focuses on different topics covered by the special issue titled 'Hardware Implementation of Machine vision Systems' including FPGAs, GPUS, embedded systems, multicore implementations for image analysis such as edge detection, segmentation, pattern recognition and object recognition/interpretation, image enhancement/restoration, image/video compression, image similarity and retrieval, satellite image processing, medical image processing, motion estimation, neuromorphic and bioinspired vision systems, video processing, image formation and physics based vision, 3D processing/coding, scene understanding, and multimedia.

Beschreibung: The computational and experimental studies have been performed to investigate the hydrodynamic process of liquid propellant reorientation for the launch vehicle series fuel tanks in microgravity environment. The VOF method was used to simulate the free surface flow of gas-liquid. The process of the liquid propellant reorientation started from initially curved interface at low Bond number. The propellant reorientation flow procedure at high Bond number was obtained from numerical simulation and scale model experiment in drop tower. The numerical results agreed well with the experiments. The results can be used to adjust the engineering reorientation parameters.

Beschreibung: Recent measurements of the temperature profiles across the liquid-vapor interface of a steady evaporating liquid were performed in a thin planar liquid layer subjected to externally imposed horizontal temperature differences when the interface was open to air. Temperature discontinuities have been found to exist at the interface with an growing tendency as the imposed horizontal temperature difference increasing. Under the co-influence of thermocapillary convection and evaporation effect, a thin layer of 0.5 mm thick with approximate uniform temperature was found just below the liquid-vapor interface. Repeated experiments and further comparisons of the interfacial temperature profiles for different spatial positions along the streamwise center line and varying depths of the liquid layer were also carried out. And the temperature discontinuity was found related to the temperature in liquid phase, which was strongly influenced by the coupling of thermocapillary convection and evaporation effect.

Beschreibung: Today, the problem of designing suitable multiprocessor architecture tailored for a target applicationfield raises the need for a fast and efficient multiprocessor system-on-chip (MPSoC) designenvironment. Additionally, the implementation of image processing applications on MPSoC systemwill need to exploit the parallelism and the pipelining in algorithms with the hope of deliveringsignificant reduction in execution times. To take advantage of parallelization on homogeneousMPSoCs and to reduce the programming effort, the proposed design methodology offers moreopportunities for accelerating the parallelization of sequential processing image algorithms on pipelinearchitecture. Our approach provides rapid prototyping tool as a graphic programming environment(CubeGen). Further, it offers a set of parallel software skeletons as a communication library,providing a software abstraction to enable quick implementation of complex image processingapplications on field-programmable gate array (FPGA) platform. The design of homogeneousnetwork of communicating processor is presented from the hardware and software specification downto synthesizable hardware description. Then, we extend our approach to support more complexapplications by implementing a soft multiprocessor for 'multihypotheses model-driven approach forroad recognition' and show the impact of various configuration choices (hardware and software) tomatch the specific application needs. Using the images of a real road scene, the performance resultsof the road recognition algorithm on a Xilinx Virtex-6 FPGA platform not only achieve the desiredlatency but also further improve the tracking performance which depends mainly on the number ofhypotheses.

Beschreibung: To develop a new composite adsorbent with high performance, fir sawdust and CaCl 2 are selected as raw materials. The mass transfer is enhanced by carbonizing and activating the sawdust and heat transfer is enhanced by adding expanded graphite into the adsorbent. The effect of the preparation temperature and the expanded graphite content on the adsorption performance is investigated. The results show that the new adsorbent exhibits a high adsorption performance due to its high porosity, uniform distribution and high content of CaCl 2 and high thermal conductivity. Also, the experimental results indicate that the rate of ammonia adsorption on the adsorbent depends on the expanded graphite content and the carbonization and activation temperature. The adsorbent prepared at 500°C and with the expanded graphite content of 30% has the best performance in terms of the adsorption refrigeration, which adsorbs ammonia as high as 0.37 g g −1 at 10 min.

Beschreibung: Highly c -axis-oriented GaN films were deposited on Ti coated glass substrates using low temperature electron cyclotron resonance plasma enhanced metal organic chemical vapor deposition system (ECR-PEMOCVD) with trimethyl gallium (TMGa) as gallium source. The influence of TMGa flux on the properties of GaN films were systematically investigated by reflection high energy electron diffraction (RHEED), X-ray diffraction analysis (XRD), atomic force microscopy (AFM) and Raman scattering. The GaN film with small surface roughness and high c -axis preferred orientation was successfully achieved at the optimized TMGa flux of 1.0 sccm. The ohmic contact characteristic between GaN and Ti layer was clearly demonstrated by the near-linear current-voltage ( I–V ) curve. The GaN/Ti/glass structure has great potential to dramatically improve the scalability and reduce the cost of solid-state lighting light emitting diodes.

Beschreibung: The effect of microstructure and surface chemistry on nicotine adsorption capacity of almond-shell-based activated carbon was studied. Almond-shell-based activated carbon was reactivated or modified with steam, ZnCl 2 and NaHSO 4 separately. The surface area and pore structure parameters of activated carbon were determined from the adsorption-desorption isotherm of nitrogen at 77 K. Boehm titration and FTIR were explored to determine the surface oxygen groups. The results revealed that nicotine adsorption from solution on carbons depend on the micropores and phenolic groups. A strong correlation between the amounts of adsorbed nicotine and the phenolic groups was observed, whereas the higher amounts of carboxylic groups decrease the nicotine adsorption capacity on activated carbons.

Beschreibung: A new protocol, called fully distributed space-time coded (FDSTC) protocol having information exchange between relays, is proposed and compared with the conventional distributed space-time coded (DSTC) protocol using non-regenerative relays (NR-relays) and regenerative relays (R-relays). Closed-form error probabilities are derived to verify the simulations. In terms of error performance, the FDSTC protocol gets significant average signal-to-noise ratio (SNR) gains (3.7 dB for NR-relays and 18.1 dB for R-relays). In addition, the impact of the relative distance of relays on the required SNR is reduced up to 70\%. The system diversity order using the FDSTC protocol is higher than that using the DSTC protocol (especially, the FDSTC protocol obtains full diversity with NR-relays). As a result, at the same spectral efficiency, FDSTC has better performance in terms of outage probability in high SNR regions. In terms of energy efficiency, the FDSTC protocol is shown to outperform DSTC for long-range transmissions.

Beschreibung: In this paper, a new class of Fourier-based matrices is studied for deterministic compressed sensing.Initially, a basic partial Fourier matrix is introduced by choosing the rows deterministically fromthe inverse discrete Fourier transform (DFT) matrix. By row/column rearrangement, the matrix isrepresented as a concatenation of DFT-based submatrices. Then, a full or a part of columns of theconcatenated matrix is selected to build a new $M \times N$ deterministic compressed sensing matrix, where $M=p^r$ and $N=L (M+1)$ for prime $p$, and positive integers $r$ and $L \leq M-1$. Theoretically,the sensing matrix forms a tight frame with small coherence. Moreover, the matrix theoreticallyguarantees unique recovery of sparse signals with uniformly distributed supports. From the structureof the sensing matrix, the fast Fourier transform (FFT) technique can be applied for efficient signalmeasurement and reconstruction. Experimental results demonstrate that the new deterministic sensingmatrix shows empirically reliable recovery performance of sparse signals by the CoSaMP algorithm.

Beschreibung: The 12 May 2008 M s 8.0 Wenchuan earthquake caused notable changes in the water levels of wells in the Three Gorges area. This work examines the relationship between these co-seismic changes in water level and the changes in aquifer parameters. Three wells in the area with good responses to earth tide were chosen for analysis. Water-level data from February to June 2008 were used to calculate the aquifer transmissivity, permeability and specific storage of the rocks, and analyze the relationship between the co-seismic responses of the wells and their aquifer parameters. The results show that the Wenchuan earthquake changed these parameters considerably, thereby controlling co- and post-seismic variations of water level. The values of these parameters prior to the earthquake are linearly related with the amplitudes of co-seismic variations in water level. The larger the aquifer transmissivity, the more remarkable the co-seismic change in water level. During the earthquake, changes in aquifer parameters were found to be associated with co-seismic variations in water level, with the larger changes occurring when the co-seismic variation in water level was larger. The tectonic setting has a certain degree of influence on the co- and post-seismic changes in water level. The permeability structures of the fault zone appear to determine the manner of co-seismic variation in water level. Moreover, it seems that the water level in wells where groundwater converges more easily can recover faster following an earthquake. Insight from this study helps to improve understanding of the characteristics of water-level changes caused by earthquakes.

Beschreibung: The P2X 7 receptor (P2X 7 R) is an important member of the P2X family of ligand-gated ion channels that respond to ATP as the endogenous agonist. Studies suggest that P2X 7 R plays a potentially pivotal role in a variety of physiological functions, including peripheral and central neuronal transmission, smooth muscle contraction, and inflammation. Thus, P2X 7 R may be a potential target for drug development. Here, we used a FlexStation to examine the function of recombinant P2X 7 R stably expressed in human embryonic kidney 293 cells and to compare three high-throughput screening assays: a membrane potential assay, an ethidium bromide uptake assay, and a calcium influx assay. We found that all three assays were suitable for the analysis of P2X 7 R, but the calcium influx assay was the most robust and is the best choice as a first high-throughput screening assay when embarking on a P2X 7 R drug discovery project.

Beschreibung: The wettability of boron nitride nanotube (BNNT) films was modified using a combination of pulsed and continuous wave (CW) mode plasma. The combined mode effectively modified the wettability of BNNT films and kept the nanostructures intact. The BNNT films changed from superhydrophobic to superhydrophilic after combined mode treatment at 600 W min. In contrast, the contact angle controllable decreased linearly in a controllable way with increasing energy input before eventually becoming superhydrophilic after 1000 W min of CW mode treatment. A high concentration of graft functional groups formed, along with point defects. More point defects formed when using combined modes and higher energy input. Mainly amine functional groups were grafted by combined mode plasma, while the CW mode plasma led to more formation of amide and imine on the BNNTs. Research into controllable wettability and selection of grafted functional groups should enable promising applications of BNNTs in composites and biology in the future.

Beschreibung: 4G cellular systems envisions a comprehensive all-IP-based solution, including voice, data, and streamed multimedia at much higher data rates and spectral efficiency. Emerging standards and technologies like LTE and M-WiMAX are actually leading towards this vision. The objective of this special issue is to address specific research research issues and solutions on different aspects of 4G wireless systems and beyond. The total six papers included in this special issue demonstrates research outcomes in different aspects of 4G wireless, like scheduling, resource allocation, cognitive and cooperative communications, multicast services and coverage and planning of small cells. We hope that the research results included in this special issue will serve as an important step for further research and development in 4G wireless communication systems.

Beschreibung: This paper has two main contributions. The first is a Bayesian framework for removing two common types of degradations on video known as blotches and line scratches. Most removal techniques assume complete obliteration of the original data at the corrupted sites. This often leads to the introduction of restoration artifacts during removal. Our framework is based on modeling corruption as a semi-transparent layer. This model was introduced earlier by Ahmed et al. (ICIP 2009) for the problem of blotch removal. We show much more blotch removal results than the previous work, and we extend the semi-transparent corruption model to the problem of line removal. The second contribution of this paper is an automated technique for ground-truth generation from infrared scans of corruptions. Previous ground-truth generation efforts require manually inpainting the corrupted regions. The restoration results are evaluated by comparing the reconstructed data against the ground-truth estimates. Comparisons with current blotch and line removal techniques show that the proposed corruption removal framework produces better removal and generates less restoration artifacts.

Beschreibung: The modern society evolves into a sensorial network environment where individual sensor data can be transformed into cumulative and comprehensive representation for human. In a real time, it is independent of current location or behavior. The only limits to increase productivity and to create a smarter surrounding environment are personal habits and technology progress. The paper describes sensorial framework, which is dealing with the current aspects of technology, sociology, and usability in daily life usage of ubiquitous mobile devices with sensors, and arising computed and energy power. Nowadays, most of the common tasks of our lives are mainly influenced by network and social connectivity where infrastructural speed limits are provided by the information flow.

Beschreibung: A novel speech bandwidth extension method based on audio watermark is presented in this paper. The time-domain and frequency-domain envelope parameters are extracted from the high-frequency components of speech signal, and then these parameters are embedded in the corresponding narrowband speech bit stream by the modified least significant bit watermark method which uses perception property. At the decoder, the wideband speech is reproduced with the reconstruction of high-frequency components based on the parameters extracted from bit stream of the narrowband speech. The proposed method can decrease poor auditory effect caused by large local distortion. The simulation results show that the synthesized wideband speech has low spectral distortion and its speech perception quality is greatly improved.

Beschreibung: Controllable synthesis of uniform and single-crystalline CdMoO 4 nano-octahedra has been successfully realized at large-scale by a facile reverse-microemulsion route at room temperature. The structures, compositions and morphologies of the as-prepared products were characterized in detail by X-ray powder diffraction (XRD), field-emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM), respectively. According to the thermochemical cycle, the relationship between the standard molar enthalpy of formation of nano-CdMoO 4 and bulk CdMoO 4 was proposed for the first time. In combination with micro-calorimetry, the standard molar enthalpies of formation at 298.15 K of as-ynthesized CdMoO 4 nano-octahedra were obtained.

Beschreibung: Cognitive radio (CR) enriches wireless technology systems by harnessing spectrum white spaces. Such systems require continuous and reliable sensing to provide high-quality service to their users and to minimize the interference they may cause to legacy networks. As the simplicity of implementation of energy detectors and their incoherent requirements make them an ideal candidate for this type of application, this work provides a further mathematical analysis to the probability of detection over different fading channels. We derive a tight closed-form expression for the probability of detection over Nakagami channels. In addition, we introduce an accurate recursive algorithm to compute the probability of detection for an odd degree of freedom over additive white Gaussian noise channels, which has been overlooked in the literature so far. Finally, we present the simulation results which concur with the numerical results and which are also a perfect match with the mathematical expressions derived.

Beschreibung: We investigate the estimation of the time of arrival (ToA) of a radio signal transmitted over a flat-fading channel. The path attenuation is assumed to depend only on the transmitter-receiver distance and the path loss exponent (PLE) which, in turn, depends on the physical environment. All previous approaches to the problem either assume that the PLE is perfectly known or rely on estimators of the ToA which do not depend on the PLE. In this paper, we introduce a novel analysis of the performance of the maximum likelihood (ML) estimator of the ToA under an imperfect knowledge of the PLE. Specifically, we carry out a Taylor series expansion that approximates the bias and the root mean square error of the ML estimator in closed form as a function of the PLE error. The analysis is first carried out for a path loss model in which the received signal gain depends only on the PLE and the transmitter-receiver distance. Then, we extend the obtained results to account also for shadow fading scenarios. Our computer simulations show that this approximate analysis is accurate when the signal-to-noise ratio (SNR) of the received signal is medium to high. A simple Monte Carlo method based on the analysis is also proposed. This technique is computationally efficient and yields a better approximation of the ML estimator in the low SNR region. The obtained analytical (and Monte Carlo) approximations can be useful at the design stage of wireless communication and localization systems.

Beschreibung: In this paper, efficient power allocation strategies for multi-hop multi-branch amplify-and-forward networks are developed in generalized fading environments. In particular, we consider the following power optimization schemes: \emph{i)} minimizing of the all transmission powers subject to an outage constraint; and \emph{ii)} minimizing the outage probability subject to constraint on total transmit powers. In this work, we first derive asymptotically tight approximations for the statistics of the received SNR in the system under study with maximal ratio combining (MRC) and selection combining (SC) combiners. With the statistical characterization of the received SNR, we then carryout a thorough performance analysis of the system. Finally, the asymptotic expression of the outage probability is used to formulate the original optimization problems using geometric programming. The geometric programming can be readily transformed into nonlinear convex optimization problem and therefore solved efficiently and globally using the interior-point methods. Numerical results are provided to substantiate the analytical results and to demonstrate the considerable performance improvement achieved by the power allocation.

Beschreibung: Endothelial cell therapy has been implicated to enhance tissue regeneration and vascularization in ischemic kidney. However, no published study has yet examined direct effects of endothelial cell treatment in kidney recovery. This study investigated the therapeutic efficacy of endothelial cells in a mouse model with acute kidney injury (AKI). Thus, human embryonic stem cells-derived endothelial cells (hESC-ECs) labeled with a reporter system encoding a double fusion reporter gene for firefly luciferase (Fluc) and green fluorescent protein (GFP) were characterized by Fluc imaging and immunofluoresence staining. Cultured hESC-ECs (1×10 6 ) were injected into ischemic kidney shortly after AKI. Survival of the transplanted hESC-ECs was monitored in vivo from day 1 to 14 after endothelial cell transplantation and potential impact of hESC-EC treatment on renal regeneration was assessed by histological analyses. We report that a substantial level of bioluminescence activity was detected 24 h after hESC-EC injection followed by a gradual decline from 1 to 14 d. Human ESC-ECs markedly accelerated kidney cell proliferation in response to ischaemia-induced damage, indicated by an elevated number of BrdU + cells. Co-expression of Sca-1, a kidney stem cell proliferation marker, and BrdU further suggested that the observed stimulation in renal cell regeneration was, at least in part, due to increased proliferation of renal resident stem cells especially within the medullary cords and arteriole. Differentiation of hESC-ECs to smooth muscle cells was also observed at an early stage of kidney recovery. In summary, our results suggest that endothelial cell therapy facilitates kidney recovery by promoting vascularization, trans-differentiation and endogenous renal stem cell proliferation in AKI.

Beschreibung: For about three decades, DNA-based nanotechnology has been undergoing development as an assembly method for nanostructured materials. The DNA origami method pioneered by Rothemund paved the way for the formation of 3D structures using DNA self assembly. The origami approach uses a long scaffold strand as the input for the self assembly of a few hundred staple strands into desired shapes. Herein, we present a 3D origami “roller” (75 nm in length) designed using caDNAno software. This has the potential to be used as a template to assemble nanoparticles into different pre-defined shapes. The “roller” was characterized with agarose gel electrophoresis, atomic force microscopy (AFM) and transmission electron microscopy (TEM).

Beschreibung: The newly emerged adult females of Schistocerca gregaria were separated and kept in the rearing conditions without males to examine the detailed developmental characteristic of the no mating females and carefully observed the developmental progress of non-fertilised eggs laid by virgin females. The results showed that the females kept without males survived in average 43 d, i.e. 58% of the life span of mated controls, and laid correspondingly fewer egg pods. The size of egg batches, the weight of eggs, and their content of ecdysteroids were normal but the hatch rate was reduced to 18.27%. Blocks of early embryogenesis (58.43%) and hatching failures (23.29%) were the major causes of death. Moreover, most of the hatched insects died during the postembryonic development and only a few females reached the adult stage. All insects that developed until the penultimate or last larval instar or reached the adult stage were females.

Beschreibung: In this article, we present a deletion algorithm in the duality computer that deletes a marked state from an even superposition of all basis-states with certainty. This duality computer deletion algorithm requires a single query, and this achieves exponential speedup over classical algorithm. Using a duality mode and recycling quantum computing, we provide a realization of this duality computer deletion algorithm in quantum computer.

Beschreibung: Nano-opto-electronics for biomedicine is a developing interdisciplinary field. Related areas of this field are tried to be classified and outlined herein. Progresses in the different areas were reviewed based on the research development of the invited experts. Prospects of nano-opto-electronics for biomedicine are discussed.

Beschreibung: Glucagon-like peptide-1 (GLP-1) is a polypeptide incretin hormone that glucose-dependently promotes the secretion and synthesis of insulin. However, its half-life is extremely short. To enhance its half-life, we developed a long-acting GLP-1 derivative KTP with controlled release, designed on the basis of another GLP-1 derivative GP62. The kinetics and bioactivity of KTP were evaluated in Sprague Dawley (SD) rats. Long-term treatment of KTP was performed in db / db mice. Mice were treated twice daily with subcutaneous injections of KTP (1.2 mg/kg body weight), Exendin-4 (0.1 mg/kg body weight) or vehicle (phosphate buffered saline (PBS), pH 7.4) for 60 days. KTP had a longer half-life, as well as further increasing the secretion and production of insulin and reducing blood glucose concentrations, than GP62. Long-term treatment with KTP also induced anorexia, decreased water and food intake, decreased weight gain, improved blood glucose and blood lipid and ameliorated pancreatic damage and fatty liver in db / db mice.

Beschreibung: The technology for through-wall human detection with ultra-wideband (UWB) radar was discussed. Due to the large amount of UWB radar data, compressive sensing theory was introduced and compressed UWB radar data can be collected. The singular value decomposition algorithm was used to acquire the singular values of compressed radar data. The compressed UWB radar data were collected at two statuses of human being for gypsum wall. The experimental results showed that the singular values with a human target were increased compared with those without a target.

Beschreibung: Second order statistics play an important role in data modeling. Nowadays there is a tendency toward measuringmore signals with higher resolution (e.g. high resolution video), causing a rapid increase of dimensionality of themeasured samples, while the number of samples remains more or less the same. As a result the eigenvalueestimates are significantly biased as described by the Marcenko Pastur equation for the limit of both the numberof samples and their dimensionality going to infinity. By introducing a smoothness factor, we show that theMarcenko Pastur equation can be used in practical situations where both the number of samples and theirdimensionality remain finite.Based on this result we derive methods, one already known and one new to our knowledge, to estimate thesample eigenvalues when the population eigenvalues are known. However, usually the sample eigenvalues areknown and the population eigenvalues are required. We therefore applied one of the these methods in afeedback loop, resulting in an eigenvalue bias correction method.We compare this eigenvalue correction method with state-of-the-art methods, and show that our methodoutperforms other methods particularly in real life situations often encountered in biometrics: underdeterminedconfigurations, high dimensional configurations and configurations where the eigenvalues are exponentiallydistributed.

Beschreibung: The theory of compressive sensing is briefly introduced, and some construction methods for measurement matrix are deduced. A measurement matrix based on Kronecker product is devised, and it has been proved in mathematical proof. Numerical simulations on 2-D image verify that the proposed measurement matrix has better performance in storage space, construction time, and image reconstruction effect when compared with commonly used matrices in compressive sensing. This novel measurement matrix offers great potential for hardware implementation of compressive sensing in image and high-dimensional signal.

Beschreibung: The paper is to design and construct a coupled elasto-plasticity damage constitutive model for concrete. Based on the energy dissipation principle, the Hsieh-Ting-Chen four-parameter yield function is used. The model can reflect different strength characteristics of concrete in tension and compression, and reduce the limitation and lacuna of the traditional damage constitutive models for concrete. Furthermore, numerical test for concrete stress-strain relation under uniaxial tension and compression is given. Moreover, the damage process of concrete gravity dam is calculated and analyzed in seismic load. Compared with other damage constitutive models, the proposed model contains only one unknown parameter and the other parameters can be found in the Hsieh-Ting-Chen four-parameter yield function. The same damage evolution law, which is used for tension and compression, is good for determining stress-strain constitutive and damage characteristics in complex stress state. This coupled damage constitutive models can be applied in analyzing damage of concrete gravity dam and arch dam.

Beschreibung: In this study, a fouled ballast taken from the site of Sénissiat, France, was investigated. For the hydraulic behaviour, a large-scale cell was developed allowing drainage and evaporation tests to be carried out with monitoring of both suction and volumetric water content at various positions of the sample. It was observed that the hydraulic conductivity of fouled ballast is decreasing with suction increase, as for common unsaturated soils. The effect of fines content was found to be negligible. For the mechanical behaviour, both monotonic and cyclic triaxial tests were carried out using a large-scale triaxial cell. Various water contents were considered. The results were interpreted in terms of shear strength and permanent axial strain. It appeared that the water content is an important factor to be accounted for since any increase of water content or degree of saturation significantly decreases the shear strength and increases the permanent strain. Constitutive modelling has been attempted based on the experimental results. The model in its current state is capable of describing the effects of stress level, cycle number and water content.

Beschreibung: In five-axis machining, tool orientation above a blade stream surface may lead to tool collision and a decrease in workpiece rigidity. Hence, collisionless tool orientation smoothing (TOS) becomes an important issue. On the basis of a constant scallop height tool path, the triangular facets in the faces, vertices format are constructed from cutter contact (CC) using the Voronoi incremental algorithm. The cutter location (CL) points candidate set is represented by an oblique elliptic cone whose vertex lies at CC using NURBS envelope. Whether the CL point is above its CC is judged by the dot product between the normal vector and the point on triangulation nearest to the CL point. The curvatures at CC are obtained by fitting a moving least square (MLS) quadratic patch to the local neighborhood of a vertex and calculating eigenvectors and eigenvalues of the Hessian matrix. Triangular surface elastic energy is employed as the weight in selection from the NURBS envelope. The collision is judged by NURBS surface intersection. TOS can then be expressed by selecting a CL point for each CC point and converted into a numerical control (NC) code automatically according to the postprocessor type of the machine center. The proposed method is verified by finishing of a cryogenic turboexpander impeller of air separation equipment.

Beschreibung: Pollutant transport in overland flow over surfaces with spatially varying microtopography, roughness, and infiltration was investigated using the diffusion wave equation and transport rate-based equation. The finite volume method in space and an implicit backward difference scheme in time were employed in the numerical solution of the 2D governing equations. The developed model was first tested against an analytical solution and an experimental study involving overland flow and the associated pollutant transport, subsequently a series of numerical tests were carried out. Non-point source pollution was investigated under spatially varying microtopography, roughness, and infiltration. The simulation results showed that microtopography and roughness were the dominant factors causing significant spatial variations in solute concentration. When the spatially varying microtopography was replaced by a smooth surface, the result was an overestimation of the solute rate at the outlet of the upland. On the other hand, when the spatially varying roughness was replaced by the average roughness and spatially varying infiltration rate by the average infiltration rate, the pollutant discharge at the outlet of the upland was not significantly affected. The numerical results further showed that one cannot ignore the spatial variations of slope and roughness when investigating the local pollutant concentration distribution.

Beschreibung: The ability of a micro-groove to prevent the spreading of HFE-7100 fluid (C 4 F 9 OCH 3 ) having low surface tension (γ = 13.6 mN/m) on a surface is studied. In this study, micro-grooves were made around square openings of a plate made of either polycarbonate or 316 stainless steel. To verify effectiveness of micro-grooves to stop the spread of HFE-7100, experiments were done under non-saturated and saturated conditions. Under non-saturated conditions the micro-grooves on both materials confined the liquid up to apparent angle of 55 ± 5° due to the edge effect. Saturated gas-vapor mixture with vapor mass fraction of w v = 88% and w v = 97% did not significantly influence the confinement of the liquid by the micro-groove. This result is promising for application of micro-grooved plates in CIMEX experiment planned for ISS.

Beschreibung: There exists an instrument SODI (Selected Optical Diagnostic Instrument) on the ISS where series of the DCMIX (Diffusion Coefficients in Mixtures) experiments are conducted by members of the ESA Topical Team. The study is addressed to the performance of thermal design of SODI instrument for DCMIX configuration. We report the results on the temperature fields which were measured interferometrically both in two ground setups (one thermally optimized; the other one, the engineering model of the ISS SODI-DCMIX experiment: non optimized) and in the ISS experiment itself with the respective numerical simulations. Even though monitoring of the cell with binary mixture $THN-nC_{12}$ employs only an interferometer with one wave length instead of two for other cells with ternary mixtures, it gives valuable information about the instrument performance. Temperature and concentration fields observed during the tests in the engineering model are compared with those obtained in laboratory experiments with the same liquid, with numerical simulations and with first results from the ISS in Run #16. The thermal design of the microgravity cell, being not optimized for ground experiments, exhibits a promising performance in the weightlessness condition.

Beschreibung: Motility and aging in Drosophila have proven to be highly modified under altered gravity conditions (both in space and ground simulation facilities). In order to find out how closely connected they are, five strains with altered geotactic response or survival rates were selected and exposed to an altered gravity environment of 2 g . By analysing the different motile and behavioural patterns and the median survival rates, we show that altered gravity leads to changes in motility, which will have a negative impact on the flies’ survival. Previous results show a differential gene expression between sessile samples and adults and confirm that environmentally-conditioned behavioural patterns constrain flies’ gene expression and life span. Therefore, hypergravity is considered an environmental stress factor and strains that do not respond to this new environment experience an increment in motility, which is the major cause for the observed increased mortality also under microgravity conditions. The neutral-geotaxis selected strain (strain M) showed the most severe phenotype, unable to respond to variations in the gravitational field. Alternatively, the opposite phenotype was observed in positive-geotaxis and long-life selected flies (strains B and L, respectively), suggesting that these populations are less sensitive to alterations in the gravitational load. We conclude that the behavioural response has a greater contribution to aging than the modified energy consumption in altered gravity environments.

Beschreibung: Previous studies indicated that human Adipose Tissue-derived Mesenchymal Stem Cells (AT-MSCs) cultured in simulated microgravity (sim-μg) in standard laboratory incubators alter their proliferation and differentiation. Recent studies on the stem cell (SC) niches and the influence of oxygen on SC proliferation, senescence, and differentiation point to oxygen level as one of the key regulators of SC fate. Here we present the results of a study that focussed at the evaluation of the influence of oxygen level in the cultivation of AT-MSCs in sim-μg. In detail, cells were cultured for 14 days in sim-μg using the Random Positioning Machine (RPM) and two different oxygen concentrations: 5 % and 20 %. The results were compared with those obtained at 1g in the same conditions. Affymetrix Human Gene 1.0 ST array and Gene Ontology (GO) analysis were performed. The results confirmed that in all of the sim-μg experiments oxygen concentration modulates cell signalling and adhesion, in line with the knowledge that sim-μg affects cell shape and cytoskeletal organization.

Beschreibung: Experiments with gas shear-driven rivulet flows in a minichannel of height 1.4 mm and of width 30 mm were conducted during several parabolic flights campaigns organized by the European Space Agency (ESA). Rivulet flow is defined as a particular case of liquid film flow when the film occupies only a part of the substrate without touching to the lateral walls of the channel. A high frequency schlieren technique has been used for visualization of the two-phase flows. It is shown that surface tension becomes the dominating force with decreasing of the gravity level, which results in reducing of the rivulet width. The width increases with the gravity level and with the liquid flow rate growth and reduces with the gas flow rate growth.

Beschreibung: The objective of this study was to explore the potential interaction between gravity and growth hormones on isoflavonoid accumulation. Soybean callus ( Glycine max (L.) Merr. cv. ‘Acme’) was grown in the dark for 16 days at 22 °C in a growth medium supplemented with four different combinations of phytohormones and subjected to 4- g and 8- g forces simulated in a centrifuge and 1- g in an adjacent stationary control. Isoflavonoid aglycones and their glycoside concentrations (daidzein, genistein, daidzin, 6″-O-malonyl-7-O-glucosyl daidzein, genistin, 6″-O-malonyl-7-O-glucosyl genistein) were determined in the resulting tissues. Although gravity had no significant impact on callus growth, increasing gravity reduced isoflavonoid accumulation in three out of the four phytohormone-supplemented culture media. The ratio of the auxin naphthalene acetic acid (NAA) to the cytokinin benzylaminopurine (BAP) was found to have profound effect on both callus growth and isoflavonoid accumulation. The cytokinin BAP promoted callus tissue growth, but reduced callus isoflavonoid suggesting the isoflavonoid accumulation was not keeping pace with the cell growth in the elevated concentration of BAP. On the other hand, NAA had little or no effect on callus growth, but greatly enhanced isoflavonoid accumulation. Interactive effects of gravity and hormone on isoflavonoid accumulation were evident and its implication to the mechanism by which gravity exerts the effect on plant secondary metabolites is discussed.

Beschreibung: Microgravity-induced muscle atrophy is a problem of utmost importance for the impact it may have on the health and performance of astronauts. Therefore, appropriate countermeasures are needed to prevent disuse atrophy and favour muscle recovery. Muscle atrophy is characterized by loss of muscle mass and strength, and a shift in substrate utilization from fat to glucose, that leads to a reduced metabolic efficiency and enhanced fatigability. Laser therapy is already used in physical medicine and rehabilitation to accelerate muscle recovery and in sports medicine to prevent damages produced by metabolic disturbances and inflammatory reactions after heavy exercise. The aim of the research we present was to get insights on possible benefits deriving from the application of an advanced infrared laser system to counteract deficits of muscle energy metabolism and stimulate the recovery of the hypotrophic tissue. The source used was a Multiwave Locked System (MLS) laser, which combines continuous and pulsed emissions at 808 nm and 905 nm, respectively. We studied the effect of MLS treatment on morphology and energy metabolism of C2C12 cells, a widely accepted myoblast model, previously exposed to microgravity conditions modelled by a Random Positioning Machine. The MLS laser treatment was able to restore basal levels of serine/threonine protein phosphatase activity and to counteract cytoskeletal alterations and increase in glycolytic enzymes activity that occurred following the exposure to modelled microgravity. In conclusion, the results provide interesting insights for the application of infrared laser in the treatment of muscle atrophy.

Beschreibung: Hyperspectral imaging is a growing area in remote sensing in which an imaging spectrometer collects hundreds of images (at different wavelength channels) for the same area on the surface of the Earth. Hyperspectral images are extremely high-dimensional, and require on-board processing algorithms able to satisfy near real-time constraints in applications such as wildland fire monitoring, mapping of oil spills and chemical contamination, etc. One of the most widely used techniques for analyzing hyperspectral images is spectral unmixing, which allows for sub-pixel data characterization. This is particularly important since the available spatial resolution in hyperspectral images is typically of several meters, and therefore it is reasonable to assume that several spectrally pure substances (called endmembers in hyperspectral imaging terminology) can be found within each imaged pixel. There have been several efforts towards the efficient implementation of hyperspectral unmixing algorithms on architectures susceptible of being mounted onboard imaging instruments, including field programmable gate arrays (FPGAs) and graphics processing units (GPUs). While FPGAs are generally difficult to program, GPUs are difficult to adapt to onboard processing requirements in spaceborne missions due to its extremely high power consumption. In turn, with the increase in the number of cores, multi-core platforms have recently emerged as an easier to program platform compared to FPGAs, and also more tolerable radiation and power consumption requirements. However, a detailed assessment of the performance versus energy consumption of these architectures has not been conducted as of yet in the field of hyperspectral imaging, in which it is particularly important to achieve processing results in real-time. In this article, we provide a thoughtful perspective on this relevant issue and further analyze the performance versus energy consumption ratio of different processing chains for spectral unmixing when implemented on multi-core platforms.

Beschreibung: The H.264/AVC video coding standard introduces some improved tools in order to increase compression efficiency. Moreover, the multi-view extension of H.264/AVC, called H.264/MVC, adopts many of them. Among the new features, variable block-size motion estimation is one which contributes to high coding efficiency. Furthermore, it defines a different prediction structure that includes hierarchical bidirectional pictures, outperforming traditional Group of Pictures patterns in both scenarios: single-view and multi-view. However, these video coding techniques have high computational complexity. Several techniques have been proposed in the literature over the last few years which are aimed at accelerating the inter prediction process, but there are no works focusing on bidirectional prediction or hierarchical prediction. In this article, with the emergence of many-core processors or accelerators, a step forward is taken towards an implementation of an H.264/AVC and H.264/MVC inter prediction algorithm on a graphics processing unit. The results show a negligible rate distortion drop with a time reduction of up to 98% for the complete H.264/AVC encoder.

Beschreibung: Accurate three-dimensional (3D) tracking in bistatic forward scatter radar (BFSR) is a challenging problem because of absent range resolution and poor measurements. In this article, an accurate 3D tracking method of BFSR is proposed. Aiming to overcome the filter divergence caused by large initial state estimation error, firstly, an accurate initial state estimation approach is presented based on analytic derivation and Levenberg--Marquardt algorithm, which has the potential to improve the accuracy of initial state estimation. Furthermore, in order to reduce the computation cost of filtering process and speed up the filtering convergence rate, the accurate initial state estimation and extended Kalman filter algorithm in BFSR are combined to achieve a precise target 3D tracking. Finally, the proposed accurate tracking method is verified through comparative analysis of the simulation results.

Beschreibung: The important techniques in processing hyperspectral data acquired by interference imaging spectrometer onboard Small Satellite Constellation for Environment and Disaster mitigation (HJ-1A) are studied in this article. First, a new noise estimation method, named residual-scaled local standard deviations, is used to analyze the noise condition of HJ-1A hyperspectral images. Then, an optimized maximum noise fraction (OMNF) transform is proposed for dimensionality reduction of HJ-1A images, which adopts an accurately estimated noise covariance matrix for noise whitening. The proposed OMNF method is less sensitive to noise distribution and interference existence, thus it can more efficiently compact useful data information in a low-dimensional space. The proposed OMNF is evaluated through two applications, i.e., spectral unmixing and classification, using the HJ-1A image acquired at the Bohai Sea area in China. It demonstrates that the proposed OMNF provides better performance in comparison with other traditional dimensionality reduction methods.

Beschreibung: In this paper, we suggest a general model for the fixed-valued impulse noise and propose a two-stage method for high density noise suppression while preserving the image details. In the first stage, we apply an iterative impulse detector, exploiting the image entropy, to identify the corrupted pixels and then employ an Adaptive Iterative Mean filter to restore them. The filter is adaptive in terms of the number of iterations, which is different for each noisy pixel, according to the Euclidean distance from the nearest uncorrupted pixel. Experimental results show that the proposed filter is fast and outperforms the best existing techniques in both objective and subjective performance measures.

Beschreibung: A comparison of 4 x 4 multiple-input multiple-output wireless local area network wireless communication characteristics for six different geometrical shapes is investigated. These six shapes include the straight shape corridor with rectangular cross section, the straight shape corridor with arched cross section, the curved shape corridor with rectangular cross section, the curved shape corridor with arched cross section, the L-shape corridor, and the T-shape corridor. The impulse responses of these corridors are computed by applying shooting and bouncing ray/image (SBR/Image) techniques along with inverse Fourier transform. By using the impulse response of these multipath channels, the mean excess delay, root mean square (RMS) delay spread for these six corridors can be obtained. Numerical results show that the capacity for the rectangular cross section corridors is smaller than those for the arched cross section corridors regardless of the shapes. And the RMS delay spreads for the T-and the L-shape corridors are greater than the other corridors.

Beschreibung: In this article, we study the medium access control (MAC) problem inunderwater wireless acoustic networks. We explore the random accessand handshaking (i.e., RTS/CTS) techniques in both single-channeland multi-channel network scenarios. We model and analyze these twoapproaches, and conduct extensive simulations to study theirperformance in various network conditions. Based on our results, weobserve that the performance of both approaches are affected by manyfactors such as data rate, propagation delay and packet size. Ourresults show that the RTS/CTS approach is more suitable for densenetworks with high date rate, whereas the random access approach ispreferred in sparse networks with low data rate. Our results alsodemonstrate that multi-channel techniques can potentially help uscombat the long delay feature of underwater acoustic channels.However, uncoordinated random channel access cannot fully exploitthe advantages of the multi-channel network settings and it performseven worse than the single-channel random access protocol. Only withcareful design and coordination such as multi-channel access withRTS/CTS handshaking process, can multi-channel MAC protocols greatlyimprove the system performance. We believe that this study willprovide useful guidelines for efficient MAC design in underwaterwireless acoustic networks.

Beschreibung: In order to mitigate the mutual interference between ultra-wideband (UWB) impulse radio and other existing wireless systems, a novel adaptive interference-avoiding UWB pulse, in the context of the appealing cognitive radio, is presented based on the radial basis function neural networks. Theoretical and implementation architecture for UWB pulse generator is addressed. Transmission performance in the presence of narrowband interference including tone interference is comprehensively analyzed. The presented generator can adaptively change the spectrum shape of UWB signals according to the authorized users' working states, and hence the mutual interference between UWB and other systems sharing the frequency bands can efficiently be avoided. The critical performance indication parameters, such as the SNR, SIR, and BER of UWB communication links, are also derived. Performance evaluations and comparisons between the proposed scheme and other pulse optimization methods have been provided based on the extensive numerical simulations. It is demonstrated that the presented pulse can indeed achieve much superior performance in terms of either single-link BER or anti-jamming capability.

Beschreibung: In this paper, a new pressure reducing valve (PRV) with an orifice plate is proposed. The main objective is to explain the mechanisms of pressure reduction and energy conversion in the new PRV. A numerical simulation method was used to investigate the PRV internal flow field and to analyze the throttling effects of the orifice plate and the transform of thermal parameters as outlet pressure, outlet temperature, velocity, and superheat. A structure improvement method for the valve body and orifice plate is put forward to reduce energy loss. The governing equations for internal flow numerical simulation are composed of the continuity, momentum, energy and k - ɛ transport equations, based on isotropic eddy viscosity theory. Different valve plug displacement models were built to describe the double throttling process. Our analysis shows that the steam pressure drops twice and the degree of superheat increases. There are also lots of eddies which clog the flow channel and disturb the steam flow in the valve cavity after the valve plug and the outlet cavity. After modifying the structure, the numerical results show a better performance of steam flow.

Beschreibung: A 2D and 3D kinematically admissible rotational failure mechanism is presented for homogeneous slurry trenches in frictional/cohesive soils. Analytical approaches are derived to obtain the upper bounds on slurry trench stability in the strict framework of limit analysis. It is shown that the factor of safety from a 3D analysis will be greater than that from a 2D analysis. Compared with the limit equilibrium method, the limit analysis method yields an unconservative estimate on the safety factors. A set of examples are presented in a wide range of parameters for 2D and 3D homogeneous slurry trenches. The factor of safety increases with increasing slurry and soil bulk density ratio, cohesion, friction angle, and with decreasing slurry level depth and trench depth ratio, trench width and depth ratio. It is convenient to assess the safety for the homogeneous slurry trenches in practical applications.

Beschreibung: This paper describes the identification of waterflooded zones and the impact of waterflooding on reservoir properties of sandstones of the Funing Formation at the Gao 6 Fault-block of the Gaoji Oilfield, in the Subei Basin, east China. This work presents a new approach based on a back-propagation neural network using well log data to train the network, and then generating a cross-plot plate to identify waterflooded zones. A neural network was designed and trained, and the results show that the new method is better than traditional methods. For a comparative study, two representative wells at the Gao 6 Fault-block were chosen for analysis: one from a waterflooded zone, and the other from a zone without waterflooding. Results from this analysis were used to develop a better understanding of the impact of waterflooding on reservoir properties. A range of changes are shown to have taken place in the waterflooded zone, including changes in microscopic pore structure, fluids, and minerals.

Beschreibung: The long-duration fluid physics experiments on a thermocapillary-driven flow have been carried out on the Japanese Experiment Module ‘Kibo’ aboard the International Space Station (ISS) since 2008. In these experiments, various aspects of thermocapillary convection in a half-zone (HZ) liquid bridge of high Prandtl number fluid have been examined under the advantages of the long-duration high-quality microgravity environment. In 2010, the authors succeeded to realize nonlinear convective fields in the HZ liquid bridge of rather high aspect ratio. Special attention was paid on to the complex convective fields, especially on the behaviors of the hydrothermal wave (HTW) over the free surface visualized by an infrared camera. In order to evaluate the characteristics of the nonlinear convective behaviors and their transition processes, the authors indicate the images taken by the infrared camera describing the time evolution of HTW, the spatio-temporal diagram, the Fourier analysis, and the pseudo-phase space, reconstructed from the time series of the scalar information of the liquid bridge, that is, surface temperature variation. In this paper, the authors introduce the signature of complex HTW behaviors observed at the long-duration on-orbit experiments, and make comparisons with some previous terrestrial and microgravity experiments.

Beschreibung: The paper deals with the investigation of a behavior of a system of particles suspended in a fluid in a container subjected to high frequency translational vibrations of linear polarization. Pair interaction forces act on the particles under these conditions. These forces decrease with the distance and depend on the interacting particles orientation with respect to the vibration direction. The presence of these forces leads to the formation of structures in space. The problem is solved numerically using molecular dynamics method with pair interaction approximation. It is shown that the process of the structures formation consists of the fast stage of compact cluster formation and slow evolution of these clusters. It is found that for vibrations of linear polarization the particles form the chains oriented perpendicular to the direction of vibrations. At long time-scales these chains form the layers perpendicular to the direction of the vibrations and located almost periodically all over the fluid volume.

Beschreibung: Boiling in porous media is an active topic of research since it is associated with various applications, e.g. microelectronics cooling, wetted porous media as thermal barriers, food frying. Theoretical expressions customary scale boiling heat and mass transfer rates with the value of gravitational acceleration. Information obtained at low gravity conditions show a deviation from the above scaling law but refers exclusively to non-porous substrates. In addition, the role of buoyancy in boiling at varying gravitational levels (i.e. from microgravity—important to satellites and future Lunar and Martial missions, to high-g body forces—associated with fast aerial maneuvers) is still unknown since most experiments were conducted over a limited range of g-value. The present work aims at providing evidence regarding boiling in porous media over a broad range of hypergravity values. For this, a special device has been constructed for studying boiling inside porous media in the Large Diameter Centrifuge (LDC at ESA/ESTEC). LDC offers the unique opportunity to cancel the shear stresses and study only the effect of increased normal forces on boiling in porous media. The device permits measurement of the temperature field beneath the surface of the porous material and video recordings of bubble activity over the free surface of the porous material. The preliminary results presented from experiments conducted at terrestrial and hypergravity conditions, reveal for the first time the influence of increased levels of gravity on boiling in porous media.

Beschreibung: In this paper we report about the BIOKIS payload: a multidisciplinary set of experiments and measurements in the fields of Biology (4) and Dosimetry (3) performed in microgravity. BIOKIS took advantage of the last STS-134 Endeavour mission and engineering state of the art in Space Life Science. The BIOKIS payload is compact, efficient, and capable to host experiments with different samples and science disciplines. Moreover, the time overlap of biological experiments and dosimetry measurements will produce more insightful information.

Beschreibung: Aircraft parabolic flights provide repetitively short periods of reduced gravity and are used to conduct scientific and technology microgravity investigations, to test instrumentation prior to space flights and to train astronauts before a space mission. Since 1997, ESA, CNES and DLR use the Airbus A300 ZERO-G, currently the largest airplane in the world for this type of experimental research flight. This mean is managed by the French company Novespace. Since 2010, Novespace offers the possibility of flying reduced gravity levels equivalent to those on the Moon and Mars achieved repetitively for periods of more than 20 s. ESA, CNES and DLR issued an international call for experiments inviting European Scientists to submit experiment proposals to be conducted at these partial gravity levels. The scientific objectives are on one hand to obtain results at intermediate levels of gravity (between 0 and 1 g) allowing a better study of the influence of gravity, and on the other hand to give them some elements to prepare for research and exploration during space flights and future planetary exploration missions. ESA, CNES and DLR jointly organised in June 2011 the first Joint European Partial-G Parabolic Flight campaign with 13 experiments selected among 42 received proposals. Parabolas were flown during three flights providing micro-, Moon and Mars gravity levels with duration typically of 20 s, 25 s and 32 s with a mixed complement of investigations in physical and life sciences and in technology. The paper presents the approach taken to organise this campaign and the 13 selected experiments with some preliminary results are presented to show the interest of this unique research tool for microgravity and partial gravity investigations.

Beschreibung: Planarians of the species Schmidtea mediterranea are a well-established model for regeneration studies. In this paper, we first recall the morphological characters and the molecular mechanisms involved in the regeneration process, especially focussing on the Wnt pathway and the establishment of the antero-posterior axial polarity. Then, after an assessment of a space-experiment (run in 2006 on the Russian Segment of the International Space Station) on planarians of the species Girardia tigrina , we present our experimental program to ascertain the effects that altered-gravity conditions may have on regeneration processes in S. mediterrnea at the molecular and genetic level.