求解大规模优化问题的可全局收敛蝙蝠算法

为了快速求解大规模优化问题,构造出了可全局收敛的蝙蝠算法。在该算法中,将一个蝙蝠看成是优化问题的一个候选解;采用正交拉丁方原理生成蝙蝠群的初始空间位置,以达到对搜索空间的均衡分散性和整齐可比性覆盖;将蝙蝠的追随、自主、避险和从众行为用于构造每个蝙蝠的空间位置转移策略;利用蝙蝠捕获猎物时的响度和脉冲速率来确保整个蝙蝠群要么保持原状态,要么向好的空间位置转移,但绝不会向差的空间位置转移。在蝙蝠群移动过程中,蝙蝠从一个空间位置转移到另一个空间位置实现了蝙蝠群对优化问题最优解的搜索。结果表明,采用可归约随机矩阵稳定性定理可证明本算法具有全局收敛性。测试案例表明,本算法用于求解大规模优化问题时具有对不同类型优化问题适应性强且收敛速度快的优势。     

自适应多普勒补偿与变异选择的蝙蝠算法

为克服蝙蝠算法在高维优化问题上求解精度低和早熟收敛的缺点,提出一种改进的蝙蝠算法。首先根据蝙蝠相对猎物距离的远近程度,对频率引入自适应多普勒补偿策略,并结合速度偏移机制修正飞行方向,产生靠近最优个体的新位置;其次对最优个体构造自适应变异选择策略,先利用柯西变异产生的较大步长摆脱局部极值的束缚,后利用高斯变异产生的较小步长精细搜寻最优区域;最后通过调整响度和脉冲发射率,平衡算法的全局探索和局部开发能力。从理论上分析了算法的收敛性和运算复杂性,对12个标准函数在不同维度下进行仿真实验,并与近年来其他蝙蝠算法进行比较,结果表明改进的算法在求解高维优化问题上具有较优的收敛速度和精度。     

采用双模飞行的粒子群优化算法

基于对现实中鸟群飞行方式的模拟,提出一种采用双模飞行的粒子群优化算法.该算法中的粒子在搜索过程中可使用变轨和不变轨两种飞行模式,并根据群体信息反馈和自身状态选择自己的飞行模式.文中选取典型的高维复杂优化问题作为算法优化性能测试.实验表明该算法的全局搜索能力有较大提高,能有效避免早熟收敛问题,可用于求解高维的复杂优化问题.     

基于Lévy飞行特征的蝙蝠算法及其在WSN定位中的应用

针对蝙蝠算法收敛易早熟、收敛速度慢等不足,提出一种改进的基于Lévy飞行特征自适应的蝙蝠算法。采用Lévy飞行策略取代原算法中蝙蝠飞行速度和位置的更新方式,充分利用Lévy飞行的重尾效应,有效避免局部最优值的吸引,加快了收敛速度,达到寻优能力和搜索能力的平衡。在无线传感器网络自身定位应用中,把定位问题转换为一个全局优化问题,使用改进的算法进行定位计算。通过Zigbee平台的实验表明,改进后的算法在不同空间位置的定位精度更高,收敛速度更快。算法实现条件简单、精度高,具有较高的实际工程应用价值。     

动态双子群拟梯度蝙蝠算法

针对基本蝙蝠算法存在的易陷入局部最优、后期收敛速度慢等问题,提出动态双子群拟梯度蝙蝠算法。该算法利用蝙蝠脉冲发射频率将蝙蝠种群动态地划分为自由搜索种群和局部搜索种群两个子群,在局部搜索子群中利用拟梯度方向指导蝙蝠搜索。为了验证算法的有效性,通过对4个基准函数的实验测试,实验结果表明,该算法相对于基本蝙蝠算法具有较好的全局搜索能力和优化精度。     

一种改进的自适应变异蝙蝠算法

针对蝙蝠算法在解决高维复杂问题时容易陷入局部最优解和精确度不高的问题,文中提出了一种改进的蝙蝠算法。在原算法的基础上,引入一种交叉变换的方式更新蝙蝠群体的位置,一方面是为了提高蝙蝠算法的遍历性,另外还可以减小蝙蝠算法陷入局部最优解的可能性。模拟蝙蝠发声的音量变化,采用自适应的变换的方式改进蝙蝠算法最优解的选择模式,达到提高算法的精度和收敛速度的目的。最后通过标准的测试函数对改进后的算法进行数值模拟,结果显示,改进后的算法较为有效。     

一种高效的混合蝙蝠算法

针对基本蝙蝠算法存在收敛速度慢,易陷入局部最优,求解精度低等缺陷,提出一种融合局部搜索的混合蝙蝠算法用于求解无约束优化问题。该算法利用混沌序列对蝙蝠的位置和速度进行初始化,为全局搜索的多样性奠定基础;融合Powell搜索以增强算法的局部搜索能力,加快收敛速度;使用变异策略在一定程度上避免算法陷入局部最优。选取几个标准测试函数进行仿真实验,结果表明：与基本蝙蝠算法和粒子群优化算法相比,混合蝙蝠算法具有更好的寻优性能。     

来自大自然的寻优策略：像蝙蝠一样感知

蝙蝠算法是受自然界中的蝙蝠通过回声定位进行搜寻、捕食猎物行为的启发,并将多智能体系统与进化机制相结合发展而来的优化方法。作为一种新颖的仿生群体智能优化算法,分析了蝙蝠算法的仿生原理、优化机理及特点,对算法优化过程进行了定义。通过标准算例对蝙蝠算法在连续空间和离散空间的优化性能进行了仿真测试,结果表明该算法在函数优化和组合优化方面应用的可行性和有效性,具有良好的应用前景。     

基于莱维飞行的粒子群优化算法

为了有效解决粒子群优化算法易陷入局部最优的缺陷,在粒子群优化优化算法（PSO）的基础上,引入莱维飞行,提出了一种基于莱维飞行的粒子群优化算法（LPSO）。该算法在迭代过程中,对粒子位置进化效果进行判断,若粒子多次迭代后仍无法进化到更优位置,则使用莱维飞行更新粒子位置。改进后的算法增加了粒子位置变化的活力,提高了算法的有效性。仿真实验结果表明,该算法在求解全局最优时,效果优于原始粒子群优化算法,在多峰值函数优化问题中其优越性更加突出。     

一种采用动态游动模式的鱼群算法

在鱼群算法优化的研究中,针对人工鱼群算法(AFSA)存在的速度慢、精度差、早熟收敛等问题,提出一种新的改进人工鱼群算法,即一种采用动态游动模式的鱼群算法(DSMFSA).上述算法让每条“鱼”具有多种搜索模式,让每条“鱼”具有机动搜索食物的能力,并可根据群体信息的反馈和自身状态随时调整搜索方式.在数值实验中选择了几个比较典型的基准函数,用来测试上述算法的性能.实验结果表明:DSMFSA算法大大改善了人工鱼群算法(AFSA)存在的易陷入局部最优、优化精度不高之不足,明显具有比AFSA好得多的优化性能.说明改进算法具有跳出局部最优的能力,可用于求解高维的复杂优化问题.     

煤矿井下安全监控分站的设计及其仿真实现

为了设计一种具有低成本、低功耗、易操作、功能强且可靠性高的煤矿井下安全分站,针对煤矿安全生产实际,文章提出了采用MCS-51系列单片机为核心、具有CAN总线通信接口的煤矿井下安全监控分站的设计方案;首先给出煤矿井下安全监控分站的整体构架设计,然后着重阐述模拟量输入信号处理系统的设计过程,最后说明单片机最小系统及其键盘、显示、报警、通信等各个组成部分的设计;为验证设计方案的可行性与有效性,使用Proteus软件对设计内容进行仿真验证,设计的煤矿井下安全监控分站具有瓦斯、温度等模拟量参数超标报警功能和电机开停、风门开闭等开关量指示功能;仿真结果表明:设计的煤矿井下安全监控分站具有一定的实际应用价值.     

View-based model-driven architecture for enhancing maintainability of data access services

In modern service-oriented architectures, database access is done by a special type of services, the so-called data access services (DAS). Though, particularly in data-intensive applications, using and developing DAS are very common today, the link between the DAS and their implementation, e.g. a layer of data access objects (DAOs) encapsulating the database queries, still is not sufficiently elaborated, yet. As a result, as the number of DAS grows, finding the desired DAS for reuse and/or associated documentation can become an impossible task. In this paper we focus on bridging this gap between the DAS and their implementation by presenting a view-based, model-driven data access architecture (VMDA) managing models of the DAS, DAOs and database queries in a queryable manner. Our models support tailored views of different stakeholders and are scalable with all types of DAS implementations. In this paper we show that our view-based and model driven architecture approach can enhance software development productivity and maintainability by improving DAS documentation. Moreover, our VMDA opens a wide range of applications such as evaluating DAS usage for DAS performance optimization. Furthermore, we provide tool support and illustrate the applicability of our VMDA in a large-scale case study. Finally, we quantitatively prove that our approach performs with acceptable response times.     

A pragmatic multi-method investigation of discrepant technological events: Coping,attributions, and ‘accidental’ learning

Discrepant technological events or situations that entail a problem, a misunderstanding or a difficulty with the Information Technology (IT) being employed, are common in the workplace, and can lead to frustration and avoidance behaviors. Little is known, however, about how individuals cope with these events. This paper examines these events by using a multi-method pragmatic approach informed by coping theory. The results of two studies – a critical incident study and an experiment – serve to build and test, respectively, a theoretical model that posits that individuals use a variety of strategies when dealing with these events: they experience negative emotions, make external attributions, and adopt engagement coping strategies directed at solving the event, eventually switching to a disengagement coping strategy when they feel they have no control over the situation. Furthermore, users’ efforts may result in ‘accidental’ learning as they try to overcome the discrepant IT events through engagement coping. The paper ends with a discussion of the results in light of existing literature, future opportunities for research, and implications for practice.     

The Distributed Time-Triggered Simulation Scheme: Core Principles and Supporting Execution Engine

Distributed real-time simulation is a young technology field but its practice is under increasing demands. In recent years the author and his collaborators have been establishing a new approach called the distributed time-triggered simulation (DTS) scheme which is conceptually simple and easy to use but widely applicable. The concept was initiated in the course of developing a new-generation object-oriented real-time programming scheme called the time-triggered message-triggered object (TMO) programming scheme. Some fundamental issues inherent in distributed real-time simulation that were learned during recent experimental studies are discussed along with some approaches for resolving the issues. An execution engine developed to support both the TMOs engaged in control computation and the TMOs engaged in DTS is also discussed along with its possible extensions that will enable significantly larger-scale DTSs.     

Software-Konfigurationsmanagement in großen Softwareprojekten

Zusammenfassung Mit zunehmender Größe der Softwaresysteme verschärfen sich die für die Software-Herstellung typischen Probleme: Beherrschen großer Objektmengen, Erhalten der Systemkonsistenz, Kontrolle der ständigen Änderungseinflüsse und Gewährleisten einer langen Lebensdauer. Die Disziplin Konfigurationsmanagement bildet den methodischen Ansatz, diese Probleme besser zu beherrschen. Software-Konfigurationsmanagement faßt die Herstellung von Softwaresystemen als eine Abfolge von kontrollierten Änderungen an gesicherten Zwischen- und Endergebnissen auf. Dargestellt werden die Objekte und Funktionen des Software-Konfigurationsmanagements sowie die hierfür in großen Software-Projekten benötigten Methoden, Instanzen und Hilfsmittel.     

Information for Authors

正http://www.zju.edu.cn/jzus http://www.springerlink.com Aim The Journals of Zhejiang University-SCIENCE(A/B/C)are edited by the international board of distinguished Chinese and foreign scientists,and are aimed to present the latest developments and achievements in scientific research in China and     

Editorial:Brain-machine interface(BMI) and cyborg intelligence

正Brain-machine interfaces(BMIs)aim at building a direct communication pathway between the brain and an external device,and represent an area of research where significant progress has been made during the past decade.Based on BMIs,mind information can be read out by neural signals to control     

Information for Authors

正http://www.zju.edu.cn/jzus http://www.springerlink.com Aim The Journals of Zhejiang University-SCIENCE(A/B/C)are edited by the international board of distinguished Chinese and foreign scientists,and are aimed to present the latest developments and achievements in scientific research in China and overseas to the world’s scientific circles,especially to stimulate     

SCIENCE CHINA Information Sciences SUBJECT INDEX TO VOLUME 57(2014)

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Information for Authors

正http://www.zju.edu.cn/jzus http://www.springerlink.com Aim The Journals of Zhejiang University-SCIENCE(A/B/C)are edited by the international board of distinguished Chinese and foreign scientists,and are aimed to present the latest developments and achievements in scientific research in China and overseas to the world’s scientific circles,especially to stimulate