Collaborative Network Topologies in Spatial Economies

Networks and Spatial Economics - Recently, it has been shown that networks with an arbitrary degree sequence may be a stable solution to a network formation game. Further, in recent years there has...     

Energy-efficient and delay-aware mobile cloud offloading over cellular networks

Telecommunication Systems - The latest mobile applications, such as GPS, games, virus scanning, and face detection and recognition, are compute-intensive applications consuming a lot of energy when...     

图形超级计算机的可编程HIPPI接口

随着网络接近Ｇｂ／ｓ的性能，超级计算机的主机接口正在成为通讯的瓶颈。为图形级计算机ＰｉｘｅｌＰｌａｎｅｓ５设计的高性能主机接口—网络接口部件（ＮＩＵ），通过数据调度硬件与嵌入式处理器之间的平衡取得了高性能和可编程性。本文对ＮＩＵ的硬件、软件、固件及接口性能进行了分析和总结。     

Interfacial waves and hydraulic falls: Some applications to atmospheric flows in the lee of mountains

Two dimensional flow of a layer of constant density fluid over arbitrary topography, beneath a compressible, isothermal and stationary fluid is considered. Both downstream wave and critical flow solutions are obtained using a boundary integral formulation which is solved numerically by Newton's method. The resulting solutions are compared against waves produced behind similar obstacles in which the compressible upper layer is absent (single layer flow) and against the predictions of a linearised theory. The limiting waves predicted by the full non-linear equations are contrasted with those predicted by the forced Korteweg-de Vries theory. In particular, it is shown that at some parameter values a multiplicity of solutions exists in the full nonlinear theory.     

Shear-Responsive Drug Delivery Systems in Medical Devices: Focus on Thrombosis and Bleeding

Cardiovascular disease is the leading cause of death worldwide. Blood-contacting medical devices provide critical support for patients with severe respiratory and/or cardiac failure. High shear stress zones and non-biocompatible circuit can increase the risk of thrombus formation in patients. These thrombi restrict blood flow through the circuits and travel to the lungs and brain, creating significant consequences. Antithrombotic drugs are used to lower this risk, but they also raise the incidence of bleeding problems. This article explores the delicate balance between thrombosis and bleeding in medical devices by examining platelet activation and thrombosis formation under shear stress. The feasibility of a shear-responsive nanomedicine-based drug delivery system has been explored as a potential approach for targeted administration of antithrombotic medications to lower systemic drug levels and reduce the bleeding risk. Furthermore, the lack of in vitro platforms to investigate the biological behavior of antithrombotic nanoparticles is impeding their clinical translation. As a result, microfluidic technology offers a platform for investigating nanoparticle behavior in vitro and linking it to their performance in vivo. Finally, the challenges and factors that affect the functionality, stability, and circulation time of liposomal drugs are investigated to improve their efficacy for targeted drug administration in medical devices.     

Cross-modal warnings for orienting attention in older drivers with and without attention impairments

Older adults are overrepresented in fatal crashes on a per-mile basis. Those with useful field of view (UFOV) reductions show a particularly elevated crash risk that might be mitigated with vehicle-based warnings. To evaluate cross-modal cues that could be used in these warnings, we applied a variation of Posner's orienting of attention paradigm. Twenty-nine older drivers with UFOV impairments and 32 older drivers without impairments participated. Cues were presented in either a single modality or a combination of modalities (visual, auditory, haptic). Drivers experienced three cue types (valid spatial information, invalid spatial information, neutral) and an uncued baseline. Following each cue, drivers discriminated the direction of a target (a Landolt square with a gap facing up or down) in the visual panorama. Drivers with and without UFOV impairments showed comparable response times (RTs) across the different cue modalities and cue types. Both groups benefited most from auditory and auditory/haptic cues. Redundant visual cues, when paired with auditory cues, undermined performance rather than enhanced it. Overall, drivers responded faster to targets with valid spatial information followed by neutral, invalid, and uncued targets. Cues provide the greatest benefit in alerting rather than orienting the driver. The cue expected to be most effective at orienting attention - the extra-vehicular cue - performs most poorly when the spatial information is either invalid or neutral. Even when the spatial information is valid the extra-vehicular cue underperforms the auditory cues. The results suggest that temporal information dominates spatial information in the ability of cues to speed responses to targets. This study represents a first step in assessing whether combining a cognitive science paradigm and a driving simulator environment can quickly assess how different warning signals alert and orient drivers.     

Security beyond cybersecurity: side-channel attacks against non-cyber systems and their countermeasures

Side-channels are unintended pathways within target systems that leak internal information, exploitable via side-channel attack techniques that extract the target information, compromising the system’s security and privacy. Side-channel attacks are well established within the cybersecurity domain, and thus their cyber-physical systems are actively defended with countermeasures. Non-cyber systems are equally as vulnerable to side-channel attacks; however, this is largely unrecognised and therefore countermeasures to defend them are limited. This paper surveys side-channel attacks against non-cyber systems and investigates the consequent security and privacy ramifications. Side-channel attack techniques rely on respective side-channel properties in order to succeed; therefore, countermeasures that disrupt each side-channel property are identified, effectively thwarting the side-channel attack. This principle is captured within a countermeasure algorithm: a systematic and extensible approach to identifying candidate countermeasures for non-cyber systems. We validate the output of this process by showing how the candidate countermeasures could be applied in the context of each non-cyber system and in the real world. This work provides an extensible platform for translating cybersecurity-derived side-channel attack research into defending systems from non-cyber domains.

     

On the transition from displacement to mixing ventilation with a localized heat source

We investigate the steady state natural ventilation of a room heated at the base and consisting of two vents at different levels. We explore how the air flow rate and internal temperature relative to the exterior vary as a function of the vent areas, position of the vents and heat load in order to establish appropriate ventilation strategies for a room. When the room is heated by a distributed source, the room becomes well mixed and the steady state ventilation rate depends on the heating rate, the area of the vents and the distance between the lower and upper level vents. However, when the room is heated by a localised source the room becomes stratified. If the effective ventilation area is sufficiently large, then the interface separating the two layers lies above the inlet vent and the lower layer is comprised of ambient fluid. In this case the upper layer is warmer than in the well mixed case and the ventilation rate is smaller. However, if the effective area for ventilation is sufficiently small, then the interface separating the two layers lies below the inlet vent and the lower layer is comprised of warm fluid which originates as the cold incoming fluid mixes during descent from the vent through the upper layer. In this case both the ventilation rate and the upper layer temperature are the same as in the case of a distributed heat load. As the vertical separation between lower and upper level vents decreases, then the temperature difference between the layers falls to zero and the room becomes approximately well mixed. These findings suggest how the appropriate ventilation strategy for a room can be varied depending on the exterior temperature, with mixing ventilation more suitable for winter conditions and displacement ventilation for warmer external temperatures.     

An emerging role for comprehensive proteome analysis in human pregnancy research

Elucidation of underlying cellular and molecular mechanisms is pivotal to the comprehension of biological systems. The successful progression of processes such as pregnancy and parturition depends on the complex interactions between numerous biological molecules especially within the uterine microenvironment. The tissue- and stage-specific expression of these bio-molecules is intricately linked to and modulated by several endogenous and exogenous factors. Malfunctions may manifest as pregnancy disorders such as preterm labour, pre-eclampsia and fetal growth restriction that are major contributors to maternal and perinatal morbidity and mortality. Despite the immense amount of information available, our understanding of several aspects of these physiological processes remains incomplete. This translates into significant difficulties in the timely diagnosis and effective treatment of pregnancy-related complications. However, the emergence of powerful mass spectrometry-based proteomic techniques capable of identifying and characterizing multiple proteins simultaneously has added a new dimension to the field of biomedical research. Application of these high throughput methodologies with more conventional techniques in pregnancy-related research has begun to provide a novel perspective on the biochemical blueprint of pregnancy and its related disorders. Further, by enabling the identification of proteins specific to a disease process, proteomics is likely to contribute, not only to the comprehension of the underlying pathophysiologies, but also to the clinical diagnosis of multifactorial pregnancy disorders. Although the application of this technology to pregnancy research is in its infancy, characterization of the cellular proteome, unearthing of functional networks and the identification of disease biomarkers can be expected to significantly improve maternal healthcare in the future.