改进的粒子群优化算法在QoS选播路由中的应用

QoS选播路由问题是一个非线性的组合优化问题,已被证明是NP完全问题.提出一种基于改进的粒子群优化的多QoS选播路由算法.算法引入一种特殊相加算子,让较差的路径能够不断向较好的路径学习,使算法尽可能向全局最优者靠近;设计一种随机变异算子,通过对全局极值进行随机变异,保证了粒子的多样性,提高了算法跳出局部最优解的能力.实验结果表明,该算法是可行和有效的,能够在资源预留的基础上较好地满足用户对带宽和时延的要求.     

基于改进遗传算法的TD-SCDMA扇区优化

获得满意的覆盖是TD-SCDMA标准网络规划的重点,为此,在遗传算法的基础上提出基于PCCPCH RSCP覆盖和PCCPCH C/I覆盖的改进遗传算法。采用符合网络多扇区多参数性质的二进制矩阵式编码,为加快收敛速度,给出基于块的交叉方法,同时为防止过早的局部收敛,对适应度函数进行尺度变换。实验结果表明,该算法可以快速收敛到目标解,PCCPCH RSCP覆盖比例和PCCPCH C/I覆盖比例均有不同程度的提升。     

具有QoS保障功能的服务网格资源映射策略

针对网格资源映射对用户的服务质量(QoS)偏好考虑不足的问题,对保障多维QoS的网格资源映射算法进行研究,从服务网格资源的多维QoS属性分析入手,在满足用户全局约束的前提下,根据服务中各子任务的QoS约束筛选出符合要求的网格资源,并给出合理的映射结果,提出一种网格资源映射算法——QoS-Sufferage算法。利用GridSim平台进行仿真比较,结果验证了算法的有效性。     

Electric contacts inspection using machine vision

Machine vision is an excellent tool for inspecting a variety of industrial items such as textiles, printed circuit boards, electric components, labels, integrated circuits (IC), machine tools and fruits. In this paper, we propose machine vision-based inspection system for electric contact (EC), which are popularly used in switches, breakers and relays, and are important components in the electrical industry. The proposed system consists of three sub-systems, which inspect the top, side, and bottom surfaces of electric contact for different types of defects respectively. The system acquires the digital image of three views and classifies the surface defects including cracks, breaks, and scratches. For each view, this study develops different image pre-processing and feature extraction methods to enhance and detect the surface defects. The proposed system was implemented and verified using 229 samples collected from the EC production lines. Experimental results show the proposed system is effective and efficient in identifying EC defects.     

Students’ expectations of,and experiences in e-learning: Their relation to learning achievements and course satisfaction

Within only a few years, the use of e-learning has increased rapidly in Austria. In certain subjects, up to 60% of university students report using e-learning platforms at least ‘sometimes’ or ‘frequently’ (Unger & Wroblewski, 2006). Yet, which aspects of e-learning do students consider important for their learning achievements and course satisfaction? This question was addressed by surveying 2196 students from 29 universities in Austria about their expectations of, and experiences in e-learning. Multiple regression analyses using Mplus 4.21 were carried out to investigate how different facets of students’ expectations and experiences are related to perceived learning achievements and course satisfaction.     

An integrated approach for rating engineering characteristics’ final importance in product-service system development

Product-service system (PSS) approach has emerged as a competitive strategy to impel manufacturers to offer a set of product and services as a whole. A three-domain PSS conceptual design framework based on quality function deployment (QFD) is proposed in this research. QFD is a widely used design tool considering customer requirements (CRs). Since both product and services influence satisfaction of customer, they should be designed simultaneously. Identification of the critical parameters in these domains plays an important role. Engineering characteristics (ECs) in the functional domain include product-related ECs (P-ECs) and service-related ECs (S-ECs). ECs are identified by translating customer requirements (CRs) in the customer domain. Rating ECs’ importance has a great impact on achieving an optimal PSS planning. The rating problem should consider not only the requirements of customer, but also the requirements of manufacturer. From the requirements of customer, the analytic network process (ANP) approach is integrated in QFD to determine the initial importance weights of ECs considering the complex dependency relationships between and within CRs, P-ECs and S-ECs. In order to deal with the vagueness, uncertainty and diversity in decision-making, the fuzzy set theory and group decision-making technique are used in the super-matrix approach of ANP. From the requirements of manufacturer, the data envelopment analysis (DEA) approach is applied to adjust the initial weights of ECs taking into account business competition and implementation difficulty. A case study is carried out to demonstrate the effectiveness of the developed integrated approach for prioritizing ECs in PSS conceptual design.     

IEEE 802.15.4a工业无线标准的研究与应用

对目前常用的几种工业无线标准进行了简单比较,并着重介绍了低速无线个人区域网络的新标准IEEE802．15．4a及其关键技术MDMA和CCS。新标准采用Chirp扩频物理层技术作为物理层标准,对工业环境中的干扰等具有很强的鲁棒性。以IEEE802．15．4a为基础,在现场总线测控系统中构建了无线子网段,实验表明系统处于稳定运行状态,且满足一般流程工业要求。该实例为工业无线网络接入到有线网络提供了一种解决方案,新标准在工业现场的短距离传输方面将会有广阔的应用前景。     

物联网与感知矿山专题讲座之三——感知矿山物联网的特征与关键技术

指出了感知矿山物联网是在煤矿综合自动化基础上的延伸和扩展应用,因而,感知矿山物联网在很大程度上有别于综合自动化系统;由于煤矿应用的特点,感知矿山物联网与目前地面物联网应用也有一些不同之处;介绍了感知矿山物联网的特征,它主要表现在多系统综合应用、感知层开放、应用平台开放和适合构建逻辑子系统等几个方面;分析了感知层、网络层、应用层的关键技术和跨层的公共技术;给出了感知矿山物联网的开放性要求和标准建设。该文对更好地理解感知矿山物联网的建设具有一定的参考价值。     

基于ITSQEM的IT服务质量研究

在SERVQUAL模型以及软件工程产品质量模型的基础上,结合IT服务质量的内涵和范畴,提出了IT服务质量评价模型(ITSQEM);并对该模型特性及子特性进行分析,提出了模型裁剪原则以及相应指标项的度量方法,使得质量评价更具有实用性和可操作性。     

Assessing information quality of e-learning systems: a web mining approach

E-learning systems provide a promising solution as an information exchanging channel. Improved technologies could mean faster and easier access to information but do not necessarily ensure the quality of this information; for this reason it is essential to develop valid and reliable methods of quality measurement and carry out careful information quality evaluations. This paper proposes an assessment model for information quality in e-learning systems based on the quality framework we proposed previously: the proposed framework consists of 14 quality dimensions grouped in three quality factors: intrinsic, contextual representation and accessibility. We use the relative importance as a parameter in a linear equation for the measurement scheme. Formerly, we implemented a goal-question-metrics approach to develop a set of quality metrics for the identified quality attributes within the proposed framework. In this paper, the proposed metrics were computed to produce a numerical rating indicating the overall information quality published in a particular e-learning system. The data collection and evaluation processes were automated using a web data extraction technique and results on a case study are discussed. This assessment model could be useful to e-learning systems designers, providers and users as it provides a comprehensive indication of the quality of information in such systems.