A platform for P2P agent-based collaborative applications

The operational environment can be a valuable source of information about the behavior of software applications and their usage context. Although a single instance of an application has limited evidence of the range of the possible behaviors and situations that might be experienced in the field, the collective knowledge composed by the evidence gathered by the many instances of a same application running in several diverse user environments (eg, a browser) might be an invaluable source of information. This information can be exploited by applications able to autonomously analyze how they behave in the field and adjust their behavior accordingly. Augmenting applications with the capability to collaborate and directly share information about their behavior is challenging because it requires the definition of a fully decentralized and dependable networked infrastructure whose nodes are the user machines. The nodes of the infrastructure must be collaborative, to share information, and autonomous, to exploit the available information to change their behavior, for instance, to better accommodate the needs of the users to prevent known problems. This paper describes the initial results that we obtained with the design and the development of an infrastructure that can enable the execution of collaborative scenarios in a fully decentralized way. Our idea is to combine the agent-based paradigm, which is well suited to design collaborative and autonomous nodes, and the peer-to-peer paradigm, which is well suited to design distributed and dynamic network infrastructures. To demonstrate our idea, we augmented the popular JADE agent-based platform with a software layer that supports both the creation of a fully decentralized peer-to-peer network of JADE platforms and the execution of services within that network, thus enabling JADE multiagent systems (MASs) to behave as peer-to-peer networks. The resulting platform can be used to study the design of collaborative applications running in the field.     

Influence of sintering temperature on the crystallization and mechanical properties of BN-MAS composites

A type of boron nitride–magnesium aluminum silicate (BN-MAS) composite ceramics was fabricated by hot-press sintering at different sintering temperatures. The relationship between the sintering temperature and microstructure was investigated by analyzing the interaction between hexagonal boron nitride (h-BN) and the MAS phase. The main MAS phase in the composite ceramics is the α-cordierite phase at a sintering temperature of 1300°C. At temperatures above 1400°C, the inhibitory effect of h-BN on the crystallization of the MAS system is significant, and MAS mainly exists in the form of an amorphous phase. The composite sintered at 1700°C exhibited the highest bending strength of 218MPa. h-BN and MAS were co-enhanced. MAS can be used as an effective liquid-phase sintering aid to assist in the sintering of h-BN, whereas h-BN can absorb the fracture energy of the composite ceramics through the pull-out and bridging effect of the particles.     

基于Multi-Agent系统的含分布式电源电网能源优化管理

在市场运行环境下,为了寻求微电网成本利益和环境效益的最大化,提出基于Multi-Agent系统能源优化管理策略。该研究首先构建Multi-Agent系统。此系统包括市场管理Agent(MOA),微电网管理Agent(MMA),公共电网Agent(UGA)和分布式发电Agent(DGA)。根据各微电网管理Agent上报的发电计划,在市场管理Agent中设计电价竞标策略用来确定各微电网的最佳交易电价和中标电量,以确保微电网经济利益最大化。在此基础上,在各微电网管理Agent中设计能量管理策略,并采用改进粒子群算法来确定微电网内部各分布式发电Agents的最佳功率分派,从而最小化微电网的运行成本。最后仿真验证了该方案的有效性。     

Destructive and non-destructive evaluation of concrete for optimum sand to aggregate volume ratio

Aggregates are the biggest contributor to concrete volume and are a crucial parameter in dictating its mechanical properties. As such, a detailed experimental investigation was carried out to evaluate the effect of sand-to-aggregate volume ratio (s/a) on the mechanical properties of concrete utilizing both destructive and non-destructive testing (employing UPV (ultrasonic pulse velocity) measurements). For investigation, standard cylindrical concrete samples were made with different s/a (0.36, 0.40, 0.44, 0.48, 0.52, and 0.56), cement content (340 and 450 kg/m³), water-to-cement ratio (0.45 and 0.50), and maximum aggregate size (12 and 19 mm). The effect of these design parameters on the 7, 14, and 28 d compressive strength, tensile strength, elastic modulus, and UPV of concrete were assessed. The careful analysis demonstrates that aggregate proportions and size need to be optimized for formulating mix designs; optimum ratios of s/a were found to be 0.40 and 0.44 for the maximum aggregate size of 12 and 19 mm, respectively, irrespective of the W/C (water-to-cement) and cement content.     

Food safety management system performance in the lamb chain

This study describes a performance measurement of implemented food safety management system (FSMS) along the lamb chain using an FSMS-diagnostic instrument (FSMS-DI) and a Microbiological Assessment Scheme (MAS). Three slaughterhouses, 1 processing plant and 5 butcher shops were evaluated. All the actors along the lamb chain achieved a moderate risky contextual situation, operating in a basic-average FSMS, which was not enough to obtain a good food safety output. Different suggestions are advised for each actor along the lamb chain for improvements towards higher FSMS activity levels or lower risk levels in context characteristics. The combined assessment is a useful tool to identify the possible causes of poor food safety performance in the lamb chain using few sampling locations, saving time and money.     

低剂量MSCT扫描在IV P输尿管显影不良中的临床应用

目的:探讨IVP输尿管显影不良后进行低剂量MSCT扫描的应用价值。方法:IVP输尿管显影不良后,立即或择期进行低剂量MSCT扫描。根据患者的体质情况(如腰围、体重),制定了三组低剂量MSCT扫描参数,不同体质的患者用相应不同扫描参数进行低剂量MSCT扫描,体质瘦小者用低KV、低MA进行低剂量MSCT扫描。统计42例用低剂量MSCT扫描的患者资料,总结其低剂量扫描后减少X线辐射剂量;又统计低剂量MSCT扫描后对输尿管、肾脏疾病的诊断价值。结果:综合分析IVP与低剂量扫描MSCT图像,结果显示为结石是输尿管和/或肾脏结石的首发原因,占64.3%。CT可以发现IVP不能显示的小结石。输尿管显影不良的原因中,输尿管、肾脏先天性疾病所占比率为29.4%。低剂量MSCT扫描可以解决IVP输尿管显影不良的原因。另外低剂量MSCT扫描时,MAS总量一般在1200³000 MAS,平均减少2100 MAS;CTDI值平均减少59.7%,相当于患者减少210次胸部DR片检查的辐射剂量。结论:IVP输尿管显影不良时,通过低剂量MSCT扫描,减少患者X线辐射剂量,解决了IVP输尿管显影不良的原因,为临床提供正确诊断。     

电网调度操作票系统的发展与应用

主要对电网调度操作票专家系统的发展历程作了详细叙述,并对一些新技术在电网调度操作票专家系统中的应用进行了介绍,阐述了操作票专家系统应用的现状和现存的主要问题,并指出了操作票专家系统未来的发展前景。     

用于舰船电力系统重构的多代理系统设计

舰船电力系统(shipboard power system,SPS)的网络重构是故障发生时,恢复系统供电、提高舰船生命力的重要途径之一.提出一种多代理系统(multi-Agent system,MAS)模型来实现舰船电力系统的重构,存保障高优先级负荷供电的前提卜尽可能地恢复系统供电.所提出的MAS中,各代理都具备一定的推理能力,能够根据不同的环境做出合理的决策.采用Java程序设计语言和多代理软件开发框架(Java Agent development framework,JADE)设计MAS.通过舭船的典型故障算例验证所提出MAS模型的可行性和有效性.     

基于MAS和BP网络的近距离目标预测法

以轨迹拟合法为基础，将目标预测问题转化为对预测模型参数优化搜索的问题。结合MAS、BP网络和位置预测原理，提出将近距离目标视为刚体。其状态按自由度划分为6个，其中3个自由度表示空间位置，另外3个自由度表示角的转动向量，6个自由度看作6个子网，分别进行子网预测，再进行组网的近距离目标预测法。最后，以无人机为例对算法进行仿真计算，验证了其正确性和可行性。     

Solid-state nuclear magnetic resonance investigation of cation siting in LiNaLSX zeolites

The location of Li⁺ and Na⁺ cations in a series of dehydrated low-silica LiNaX zeolites (LiNaLSX, framework Si/Al ratio=1.0) were characterized by ⁷Li and ²³Na magic-angle spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy. Depending on the Li⁺ content, up to three lines were observed in the ⁷Li MAS NMR spectra attributed to Li⁺ cations on SI′, SII and SIII sites. The ²³Na MAS NMR spectra of the pure sodium form NaLSX and of LiNaLSX samples with low Li⁺ contents contain up to five lines belong to Na⁺ cations located on SI, SI′, SII, and two different SIII′ sites. LiNaLSX zeolites containing more than 40% of Li⁺ show only a single narrow line in the ²³Na MAS NMR spectra attributed to mobile sodium cations. The populations of the different cation sites were determined from the relative line intensities of the MAS NMR spectra. Below about 70% Li⁺ exchange, lithium cations are located only on sites SI′ and SII. Between 70% and 100% Li⁺ content these sites are fully occupied by Li⁺, and the population of site SIII by Li⁺ increases. It was found that the nitrogen-adsorption capacity correlates well with the occupation of Li⁺ at site SIII.