Coordination by design and the price of autonomy

We consider a multi-agent planning problem as a set of activities that has to be planned by several autonomous agents. In general, due to the possible dependencies between the agents’ activities or interactions during execution of those activities, allowing agents to plan individually may lead to a very inefficient or even infeasible solution to the multi-agent planning problem. This is exactly where plan coordination methods come into play. In this paper, we aim at the development of coordination by design techniques that (i) let each agent construct its plan completely independent of the others while (ii) guaranteeing that the joint combination of their plans always is coordinated. The contribution of this paper is twofold. Firstly, instead of focusing only on the feasibility of the resulting plans, we will investigate the additional costs incurred by the coordination by design method, that means, we propose to take into account the price of autonomy: the ratio of the costs of a solution obtained by coordinating selfish agents versus the costs of an optimal solution. Secondly, we will point out that in general there exist at least two ways to achieve coordination by design: one called concurrent decomposition and the other sequential decomposition. We will briefly discuss the applicability of these two methods, and then illustrate them with two specific coordination problems: coordinating tasks and coordinating resource usage. We also investigate some aspects of the price of autonomy of these two coordination methods.     

Efficient algorithms for erasure node placement on slotted dual busnetworks

We study the problem of placing erasure nodes among passive stations in a slotted dual bus network. Erasure nodes are known to improve throughput by allowing slot reuse. It is also known that choices made in locating erasure nodes significantly impact network congestion and overall throughput-especially when traffic patterns exhibit a high degree of locality. We present algorithms to determine optimal placements of erasure nodes that improve upon prior work on this problem: we present simpler and faster polynomial-time algorithms and also consider various useful cost measures. These algorithms can be used to solve related placement problems in which limits on congestion and existing placements are given as input, and the goal is to find the minimum number of erasure nodes required to meet the congestion bound     

Antimicrobial resistance of Salmonella isolated from food animals: A review

Salmonella enterica is recognized as one of the most common causes of bacterial foodborne illness worldwide. The majority of Salmonella infections are attributed to consumption of contaminated food of animal origin such as eggs, chicken, pork, etc. Severe Salmonella infections often require antimicrobial therapy to aid in the elimination of the infection. A potential problem that has been developing for many decades is the development of antimicrobial resistance. There has been an increasing concern over the past 30 years regarding the worldwide emergence of multidrug-resistant phenotypes among Salmonella serotypes such as S. Typhimurium, S. Enteritidis and S. Newport. A special concern is the emergence of resistance to quinolones, fluoroquinolones or extended-spectrum cephalosporins such as ceftiofur and ceftriaxone. Recently, the occurrence of Salmonella isolates resistant to these antibiotics has increased. Therefore, continuous monitoring of its prevalence and resistance in the food supply is necessary because of the public health implications of a potential spread of resistant microorganisms. Furthermore, a holistic animal management approach such as stringent control of antimicrobial agents in the livestock industry, early clinical and microbiological diagnosis, appropriate treatment, and implementation of strict sanitary standards in the food industry are also needed to significantly reduce the overall burden of salmonellosis on human health.     

水、丙酮混合工质振荡热管传热性能

采用水、丙酮以及其二元混合工质对振荡热管进行实验研究,选取35%～70%充液率,10～100 W加热功率以及水/丙酮13：1、4：1、1：1、1：4、1：13配比,将实验数据与混合工质物性、相变特点结合以研究其振荡热管传热性能。结果表明：混合溶液振荡热管启动所需功率小于水;小充液率时,除较低丙酮比例配比（如水/丙酮13：1混合工质）以外,混合工质比纯工质振荡热管不容易烧干,纯工质振荡热管在50 W时热阻就已经上升到较高数值,而混合工质振荡热管在同样的功率则维持着较低的热阻。在丙酮中加入少量水（如水/丙酮1：13混合工质）能有效改善振荡热管烧干情况,然而,少量丙酮与水混合而成的工质（如水/丙酮13：1混合工质）对振荡热管烧干情况的改善不明显;大充液率时,混合工质振荡热管的传热性能要弱于纯工质,在35～50 W,纯工质振荡热管热阻都低于混合工质,而在较大加热功率（50～100 W）,水与混合工质振荡热管仍保持着较明显的热阻差。对混合工质振荡热管的传热性能的分析可为今后更深入研究其工作机理以及传热特性理论模型的建立提供参考。     

Loading and Controlled Release of Poorly Water-Soluble Drug Telmisartan from Porous Silicon Microparticles

Silicon - To prepare porous silicon microparticles by electrochemical etching process and study telmisartan loading and release kinetics to develop controlled drug delivery system. A...     

GaSb Thermophotovoltaic Cells Grown on GaAs Substrate Using the Interfacial Misfit Array Method

We present gallium antimonide (GaSb) p–i–n photodiodes for use as thermophotovoltaic (TPV) cells grown on gallium arsenide (100) substrates using the interfacial misfit array method. Devices were grown using molecular beam epitaxy and fabricated using standard microfabrication processes. X-ray diffraction was used to measure the strain, and current–voltage (I–V) tests were performed to determine the photovoltaic properties of the TPV cells. Energy generation at low efficiencies was achieved, and device performance was critically analyzed.     

Numerical Study of Frequency and Deflection Responses of Natural Fiber (Luffa) Reinforced Polymer Composite and Experimental Validation

ABSTRACT

The natural fiber (Luffa cylindrica fiber) reinforced epoxy composite has been fabricated and their structural responses (frequency and deflection) have been computed experimentally and numerically first time using the corresponding experimental elastic properties. The numerical responses are obtained with the help of an in-house MATLAB code developed based on the higher order finite element (FE) model. The completeness of the model has been examined by comparing the current FE solutions (frequency and the central deflection) with the reference as well as in-house experimental data. The effect of fiber volume fractions on the elastic properties is verified for four different weight percentage of treated Luffa fiber (0%, 3.2%, 6.4%, and 9.6%). Finally, the inclusive behavior of the current higher order FE model and the corresponding influence of the significant design parameter of Luffa fiber-reinforced composite structure have been debated by solving different numerical examples.     

Numerical study on variation of chord modulus on the springback of high-strength steels

The International Journal of Advanced Manufacturing Technology - The advanced high-strength steels (AHSS) have become an interesting alternative to the automotive industry to reduce vehicle weight...