A novel heuristic algorithm for QoS-aware end-to-end service composition

Many works have been carried out to find the efficient algorithms for QoS-aware service composition in recent years. Nevertheless, on one hand, some of these works only consider the local QoS attributes in Web services composition; on the other hand, some ideas derived from QoS selection algorithms for network routing are directly applied in service composition without any adaption. A service composition model with end-to-end QoS constraints has been presented in this paper. An improved heuristics HCE based on the observation of characteristic of end-to-end service composition is proposed as a novel solution. Simulation results reveal the better performance of proposed heuristic compared to the other two heuristics, HMCOP and generic CE algorithm.     

Exploring the wild birds’ migration data for the disease spread study of H5N1: a clustering and association approach

Knowledge about the wetland use of migratory bird species during the annual life circle is very interesting to biologists, as it is critically important in many decision-making processes such as for conservation site construction and avian influenza control. The raw data of the habitat areas and the migration routes are usually in large scale and with high complexity when they are determined by high-tech GPS satellite telemetry. In this paper, we convert these biological problems into computational studies and introduce efficient algorithms for the data analysis. Our key idea is the concept of hierarchical clustering for migration habitat localizations, and the notion of association rules for the discovery of migration routes from the scattered location points in the GIS. One of our clustering results is a tree structure, specially called spatial-tree, which is an illusive map depicting the breeding and wintering home range of bar-headed geese. A related result to this observation is an association pattern that reveals a high possibility that bar-headed geese’s potential autumn migration routes are likely between the breeding sites in the Qinghai Lake, China and the wintering sites in Tibet river valley. Given the susceptibility of geese to spread H5N1, and on the basis of the chronology and the rates of the bar-headed geese migration movements, we can conjecture that bar-headed geese play an important role in the spread of the H5N1 virus at a regional scale in Qinghai-Tibetan Plateau.     

基于嵌入式ARM9痕量毒气检测系统的研究

基于卟啉阵列传感器和毒气接触发生化学反应导致其色谱变化的“指纹”特性原理,提出了一种以嵌入式ARM9 S3C2440A为核心、以Linux为操作系统、QT/Embedded为开发工具并利用卟啉化学传感器的痕量毒气检测装置.阐述了系统总体设计,实现了卟啉传感阵列光谱信号采集、信号处理、反应环境监控等主要功能模块及控制软件...     

Improvements in image categorization using codebook ensembles

The problem of object category classification by committees or ensembles of classifiers, each of which is based on one diverse codebook, is addressed in this paper. Two methods of constructing visual codebook ensembles are proposed in this study. The first technique introduces diverse individual visual codebooks using different clustering algorithms. The second uses various visual codebooks of different sizes for constructing an ensemble with high diversity. Codebook ensembles are trained to capture and convey image properties from different aspects. Based on these codebook ensembles, different types of image representations can be acquired. A classifier ensemble can be trained based on different expression datasets from the same training image set. The use of a classifier ensemble to categorize new images can lead to improved performance. Detailed experimental analysis on a Pascal VOC challenge dataset reveals that the present ensemble approach performs well, consistently improves the performance of visual object classifiers, and results in state-of-the-art performance in categorization.     

基于CG-MSNWF的空时自适应抗干扰算法研究

针对多级维纳滤波MSNWF(Multi-Stage Nested Winner Filter)算法的计算量大,在处理高维数据时不能满足实时性的需要问题,采用基于共轭梯度CG(Conjugate Gradient)的多级维纳滤波算法—CG-MSNWF。在相同的干扰抑制性能条件下,该算法相比于MSNWF不需要后向迭代过程,降低了计算量和对硬件存储器的要求,提高了算法的收敛速度,满足了实时性的需求。仿真结果证实了算法的实效性。     

面向多核多线程的移动对象连续K近邻查询

针对移动对象的多用户连续K近邻查询处理问题,结合多核多线程技术的发展,提出了一种基于多线程的两阶段多用户连续K近邻查询处理框架.将查询处理分为查询预处理阶段和查询执行阶段,分别执行数据更新任务和查询处理任务,每个阶段都设计了优化cache访问命中率,并利用多线程技术提高多用户连续查询处理并行性的方法及数据结构.提出了一...     

面向环境监测的传感器网络系统设计与实现

传统的环境监测方法存在着成本高、非实时、难以实现等缺点,而新兴无线传感器网络技术具有部署简便、成本低、监测范围大的优点,将其应用到环境监测具有明显的优势。结合项目需求,设计了应用于精细农业的无线传感器网络监控系统。通过试运行证明,该系统运行稳定且功耗低。     

芹菜素和山萘酚对细胞色素CYP1A2抑制机理研究

目的:我们先前的体外肝微粒体抑制活性实验,已证实芹菜素和山萘酚对细胞色素CYP 1A2有较强的抑制作用。然而,其抑制机理仍然未知。分子模拟方法能更好了解这2个天然产物对1A2的抑制机理。方法:采用分子对接、分子动力学模拟及结合自由能计算的方法,研究它们对1A2的抑制作用。结果:芹菜素和山萘酚对1A2的预测结合自由能分别是-18.01和-16.40 kcal/mol,这与实验抑制活性结果一致。在1A2结合口袋中,残基呈平面性排列,与平面芹菜素和山萘酚存在紧密的范德华和疏水相互作用,因而小分子有较强的抑制作用。此外,活性位点残基也与小分子发生氢键和盐桥等相互作用,使小分子在结合口袋中的位置得到固定。     

空间查询和路径搜索的集成处理策略

在数据库研究中,路径搜索和空间查询处理被认为是两个互不相关的领域,然而在处理具有空间约束的路径查询时,需要数据库系统提供路径计算和空间查询处理两方面的功能.为了处理路径计算中的空间约束,考虑了两类处理策略:(1) 空间运算是否在路径计算之前预处理;(2) 空间对象是否在路径计算之前预选取.基于这两类策略,应用现有的空间连接、R-树空间搜索和空间对象聚类技术,提出4种集成的空间路径查询处理方法.     

采用混沌变异的进化算法

根据混沌理论关于进化与混沌的关系,设计一种采用混沌变异算子的进化算法,并提出“尺度收缩”的变异策略。对极小值函数优化问题的仿真实例表明,混沌变异是实数编码进化算法变异算子的有效实现;而采用“尺度收缩”策略的混沌变异算子明显改善了群体平均适应值,提高了算法性能,是解决优化问题的有效方法。