基于多反应节点下WSANs路由协议研究

针对多个反应节点环境中现有无线传感器网络路由协议不能完全满足无线传感反应网络（WSANs）对能耗和实时性需求的问题,利用J-Sim对WSANs的仿真功能,设计并实现适应单反应节点选择模式的WSANs路由协议BHOER,给出仿真数据及性能分析,实验结果表明,BHOER较好地满足WSANs的应用需求。     

An analysis of thematic mapper simulator data for urban environments

Thematic mapper simulator data collected for the Los Angeles Basin in 1980 were examined to assess their utility for urban and near-urban land-cover delimitations. Spectral data for six of the thematic mapper channels were reprojected to a UTM grid and aggregated to 30-m resolution, 120 m for the thermal band. Statistics for 21 training sites representing 8 land-cover types were obtained and examined using transformed divergence calculations for intraclass variability, optimal number of channels for classification, and best channels for classification. Four channels of data are adequate for classification with the best results obtained by selection of one channel from each of the available major portions of the electromagnetic spectrum. The thermal channel data is useful for urban land-cover delineations at 30-m resolution, but its utility at 120-m resolution is not clear from this study.     

Estimating the Attraction Domain for the Boost Inverter

This work presents an approach for estimating the domain of attraction for polynomial systems with state and control‐signal constraints, including saturation. In many problems, it is possible to derive global stability properties for such systems, neglecting constraints. Consideration of the constraints usually makes the problem much more complicated. In this paper, the stability analysis performed for the unconstrained case is used for the problem as a whole. For application of the method, there are powerful computational tools that can be employed in cases of polynomial systems. The technique is not only valid for the analysis of equilibrium points, but also for other attractors, such as limit cycles. As examples, the domain of attraction for given control laws is estimated for both a nonlinear DC‐DC boost converter and for a boost inverter.     

基于约束的XML文档规范化算法

XML模式设计是XML数据库设计的关键．基于XML文档的基本概念给出了XML部分函数依赖、传递函数依赖、XML范式、XML第1到第3范式以及DTD无损联接分解的相关定义,提出XML模式规范化转换规则,给出无损联接分解的两种规范化算法,对算法的正确性、可终止性和时间复杂性进行了证明分析,并实验证明了规范化后的文档查询和存储效率有明显的提高．这将对未来的XML函数依赖保持、XML多值依赖以及XML模式设计的进一步规范化研究奠定理论基础．     

The boundaries for joint angles of isocomfort for sitting and standing males based on perceived comfort of static joint postures

This study presents data for the joint angles of isocomfort (JAI) in sitting and standing males based on perceived comfort ratings for static joint postures maintained for 60 s. The JAI value was defined as a boundary indicating joint deviation (an angle) from neutral posture, within which the perceived comfort for different body joint postures is expected to be the same. An experiment for quantifying perceived comfort ratings was conducted using the free modulus method of magnitude estimation. Based on experimental results, regression equations were derived for each joint posture, to represent the relationships between different levels of joint deviation/joint posture and corresponding normalized comfort scores. The JAI values were developed for nine verbal categories of joint comfort. The JAIs with the marginal comfort levels, one of the nine verbal categories used, for most joint postures around the wrist, elbow, neck and ankle were similar to the maximum range of motion (ROM) values for these joints. However, the JAIs with the marginal comfort category for back and hip postures were much smaller than the maximum ROM values for these joints. There were no significant differences in JAI expressed in terms of the percentage of the corresponding maximum ROM values between sitting and standing postures. The relative 'marginal comfort index', defined as the percentage of JAIs for the marginal comfort relative to the corresponding maximum ROM values, for the hip was the smallest among all joints. This was followed, in an increasing order of the marginal comfort index, by the lower back and shoulder, while the marginal comfort index for the elbow joint was the largest. The results of this study suggest that static postures maintained for 60 s cause greater discomfort for the hip joint than for the other joints studied, and less discomfort for the elbow than for the other joints. The data about JAIs can be used as guidelines for enhancing postural comfort when designing a variety of human-machine tasks where static postures cannot be eliminated.     

Geometric algorithms for digitized pictures on a mesh-connected computer

Although mesh-connected computers are used almost exclusively for low-level local image processing, they are also suitable for higher level image processing tasks. We illustrate this by presenting new optimal (in the O-notational sense) algorithms for computing several geometric properties of figures. For example, given a black/white picture stored one pixel per processing element in an n × n mesh-connected computer, we give ?(n) time algorithms for determining the extreme points of the convex hull of each component, for deciding if the convex hull of each component contains pixels that are not members of the component, for deciding if two sets of processors are linearly separable, for deciding if each component is convex, for determining the distance to the nearest neighboring component of each component, for determining internal distances in each component, for counting and marking minimal internal paths in each component, for computing the external diameter of each component, for solving the largest empty circle problem, for determining internal diameters of components without holes, and for solving the all-points farthest point problem. Previous mesh-connected computer algorithms for these problems were either nonexistent or had worst case times of ?(n2). Since any serial computer has a best case time of ?(n2) when processing an n × n image, our algorithms show that the mesh-connected computer provides significantly better solutions to these problems.     

Consistency and refinement for Interval Markov Chains

Interval Markov Chains (IMC), or Markov Chains with probability intervals in the transition matrix, are the base of a classic specification theory for probabilistic systems [18]. The standard semantics of IMCs assigns to a specification the set of all Markov Chains that satisfy its interval constraints. The theory then provides operators for deciding emptiness of conjunction and refinement (entailment) for such specifications.In this paper, we study complexity of several problems for IMCs, that stem from compositional modeling methodologies. In particular, we close the complexity gap for thorough refinement of two IMCs and for deciding the existence of a common implementation for an unbounded number of IMCs, showing that these problems are EXPTIME-complete.We discuss suitable notions of determinism for specifications, and show that for deterministic IMCs the syntactic refinement operators are complete with respect to model inclusion. Finally, we show that deciding consistency (emptiness) for an IMC is polynomial and that existence of common implementation can be established in polynomial time for any constant number of IMCs.     

Generation of Positive and Negative Tests for Parsers

A methodology for automatic positive and negative test set generation for testing parsers is described. Coverage criteria for such test sets based on the model approach to testing are proposed. Methods for the generation of test sets satisfying these criteria are discussed. Results of the application of the proposed methodology for testing parsers for various languages including C and Java are presented.     

Compact disc standards: an introductory overview

The success of the compact disc (CD) as a storage medium for digital audio has, over the last ten years, resulted in a number of initiatives to use the CD for other applications as well, e.g., as read-only memory for computers, as a storage medium for audio-visual material for multimedia applications, and as a storage medium for photographs. Each of these applications poses additional requirements on how the corresponding information is stored and retrieved, resulting in a range of different CD standards. The functional specifications of these standards are each given a specific color for ease of reference: the Red Book for CD-DA, the Yellow Book for CD-ROM, the Green Book for CD-I, etc. This paper aims at giving an overview of the various CD standards by explaining what is specified in each of the colored books and by indicating how they relate to one another.     

A Probabilistic Analysis of Multiple-drug Testing Procedures in Sports Doping Control

Athletes engaged in competition, particularly those involved in international competitions such as the Olympics, are increasingly being tested for a greater variety of banned substances; it is not unusual for tests to be conducted for 100 drugs and another 400 as metabolites. Previous studies related to the accuracy of drug testing processes have failed to properly consider the effects of testing for more than one drug. In order to identify appropriate indicators for the multiple-drug case, probability theory and accuracy concepts applicable to testing for multiple drugs are developed and applied to illustrative data. The probability that a drug-free individual will test positive for drug use is shown to be much higher than indicated by previous studies, and it is shown that an increase in the number of drugs tested for yields an approximately proportionate increase in the probability that a positive test result is erroneous. Therefore, while testing for one drug may result in a comfortably low rate of false accusations of drug use, testing for multiple drugs may well result in an unacceptably high rate. Finally, a set of empirical measures is suggested for use in cases of tests for multiple drugs; the measures will provide for comparability among laboratory proficiency studies.     

一种分布动态网络安全系统框架

网络是人类社会全新的活动空间。这个活动空间必须符合人类社会活动的规则。信息安全是其中最重要的问题。安全问题不是某个使用网络部门的事,而是需要全社会合力解决的问题。本文从入侵检测信息的标准化入手,提出了一个分布动态网络安全系统框架结构。探讨了分布动态网络安全系统框架的层次结构、通讯方式和协议,通过分布动态网络安全系统框架解决攻击源定位、攻击响应及重要应用系统的防护等问题。     

Worst-case response time analysis of real-time tasks under fixed-priority scheduling with deferred preemption

Fixed-priority scheduling with deferred preemption (FPDS) has been proposed in the literature as a viable alternative to fixed-priority pre-emptive scheduling (FPPS), that obviates the need for non-trivial resource access protocols and reduces the cost of arbitrary preemptions. This paper shows that existing worst-case response time analysis of hard real-time tasks under FPDS, arbitrary phasing and relative deadlines at most equal to periods is pessimistic and/or optimistic. The same problem also arises for fixed-priority non-pre-emptive scheduling (FPNS), being a special case of FPDS. This paper provides a revised analysis, resolving the problems with the existing approaches. The analysis is based on known concepts of critical instant and busy period for FPPS. To accommodate for our scheduling model for FPDS, we need to slightly modify existing definitions of these concepts. The analysis assumes a continuous scheduling model, which is based on a partitioning of the timeline in a set of non-empty, right semi-open intervals. It is shown that the critical instant, longest busy period, and worst-case response time for a task are suprema rather than maxima for all tasks, except for the lowest priority task. Hence, that instant, period, and response time cannot be assumed for any task, except for the lowest priority task. Moreover, it is shown that the analysis is not uniform for all tasks, i.e. the analysis for the lowest priority task differs from the analysis of the other tasks. These anomalies for the lowest priority task are an immediate consequence of the fact that only the lowest priority task cannot be blocked. To build on earlier work, the worst-case response time analysis for FPDS is expressed in terms of known worst-case analysis results for FPPS. The paper includes pessimistic variants of the analysis, which are uniform for all tasks, illustrates the revised analysis for an advanced model for FPDS, where tasks are structured as flow graphs of subjobs rather than sequences, and shows that our analysis is sustainable.     

Meme Media for Clipping and Combining Web Resources

The publication and reuse of intellectual resources using the Web technologies provide no support for us to clip out any portion of Web pages, to combine them together for their local reuse, nor to publish the newly composed object as a new Web page for its reuse by other people. This paper shows how the meme-media architecture is applied to the Web to provide such support for us. This makes the Web work as a shared repository not only for publishing intellectual resources, but also for their collaborative reediting. We will propose a general framework for clipping arbitrary Web contents as live objects, for defining IO ports on such a clip, and for the recombination and linkage of such clips based on both the original and some user-defined relationships among them. In our previous works, we proposed two separate frameworks for these three purposes; one works for the first two, and the other for the last. Here we will propose a unified framework for these three purposes, as well as its detailed internal mechanisms. Then we show how it can be easily applied to various legacy Web applications to develop innovative services.     

Halogenated ligands and their interactions with amino acids: implications for structure-activity and structure-toxicity relationships

The properties of chemicals are rooted in their molecular structure. It follows that structural analysis of specific interactions between ligands and biomolecules at the molecular level is invaluable for defining structure-activity relationships (SARs) and structure-toxicity relationships (STRs). This study has elucidated the structural and molecular basis of interactions of biomolecules with alkyl and aryl halides that are extensively used as components in many commercial pesticides, disinfectants, and drugs. We analyzed the protein structures deposited in Protein Data Bank (PDB) for structural information associated with interactions between halogenated ligands and proteins. This analysis revealed distinct patterns with respect to the nature and structural characteristics of halogen interactions with specific types of atoms and groups in proteins. Fluorine had the highest propensity of interactions for glycine, while chlorine for leucine, bromine for arginine, and iodine for lysine. Chlorine, bromine and iodine had the lowest propensity of interactions for cysteine, while fluorine had a lowest propensity for proline. These trends for highest propensity shifted towards the hydrophobic residues for all the halogens when only interactions with the side chain were considered. Halogens had equal propensities of interaction for the halogen bonding partners (nitrogen and oxygen atoms), albeit with different geometries. The optimal angle for interactions with halogens was approximately 120 degrees for oxygen atoms, and approximately 96 degrees for nitrogen atoms. The distance distributions of halogens with various amino acids were mostly bimodal, and the angle distributions were unimodal. Insights gained from this study have implications for the rational design of safer drugs and commercially important chemicals.     

Applying random stream theory to the group target detection problem

The detection problem for a group of moving targets is a generalization of the classical detection problem for a single still target. Synthesis methods for joint detection and phase coordinate measurement for objects in the group are being developed in the theory of random streams of events. In this work, we propose a Poisson approximation for a Bernoullian stream of signals generated by a group target and observed in noises for small signal/noise ratios. Using this approximation, we can significantly simplify optimal detection and parameter estimation for a group target which are hard to implement exactly. Developing suboptimal algorithms is an important problem for a number of technical applications, including, in particular, radioand hydrolocation.     

Static Analysis of Object References in RMI-Based Java Software

Distributed applications provide numerous advantages related to software performance, reliability, interoperability, and extensibility. This paper focuses on distributed Java programs built with the help of the remote method invocation (RMI) mechanism. We consider points-to analysis for such applications. Points-to analysis determines the objects pointed to by a reference variable or a reference object field. Such information plays a fundamental role as a prerequisite for many other static analyses. We present the first theoretical definition of points-to analysis for RMI-based Java applications, and we present an algorithm for implementing a flow- and context-insensitive points-to analysis for such applications. We also discuss the use of points-to information for corrupting call graph information, for understanding data dependencies due to remote memory locations, and for identifying opportunities for improving the performance of object serialization at remote calls. The work described in this paper solves one key problem for static analysis of RMI programs and provides a starting point for future work on improving the understanding, testing, verification, and performance of RMI-based software     

The most economic setting for a uniformly shifting process

A method for finding the optimal setting for a uniformly-shifting process mean is developed and an algorithm for solution (suitable for microcomputer implementation) is presented. A determination of the number of parts to be made before resetting, and the level to which the process is to be reset is made given costs for improperly sized parts and for process resetting.     

The boundaries for joint angles of isocomfort for sitting and standing males based on perceived comfort of static joint postures

This study presents data for the joint angles of isocomfort (JAI) in sitting and standing males based on perceived comfort ratings for static joint postures maintained for 60 s. The JAI value was defined as a boundary indicating joint deviation (an angle) from neutral posture, within which the perceived comfort for different body joint postures is expected to be the same. An experiment for quantifying perceived comfort ratings was conducted using the free modulus method of magnitude estimation. Based on experimental results, regression equations were derived for each joint posture, to represent the relationships between different levels of joint deviation/joint posture and corresponding normalized comfort scores. The JAI values were developed for nine verbal categories of joint comfort. The JAIs with the marginal comfort levels, one of the nine verbal categories used, for most joint postures around the wrist, elbow, neck and ankle were similar to the maximum range of motion (ROM) values for these joints. However, the JAIs with the marginal comfort category for back and hip postures were much smaller than the maximum ROM values for these joints. There were no significant differences in JAI expressed in terms of the percentage of the corresponding maximum ROM values between sitting and standing postures. The relative ‘marginal comfort index’, defined as the percentage of JAIs for the marginal comfort relative to the corresponding maximum ROM values, for the hip was the smallest among all joints. This was followed, in an increasing order of the marginal comfort index, by the lower back and shoulder, while the marginal comfort index for the elbow joint was the largest. The results of this study suggest that static postures maintained for 60 s cause greater discomfort for the hip joint than for the other joints studied, and less discomfort for the elbow than for the other joints. The data about JAIs can be used as guidelines for enhancing postural comfort when designing a variety of human-machine tasks where static postures cannot be eliminated.     

The strategic value of supply chain visibility: increasing the ability to reconfigure

To understand the role of supply chain visibility in creating strategic value, this study uses the dynamic capabilities view to uncover the nature of supply chain visibility. The study identifies four important constructs of supply chain visibility that are helpful in driving supply chain reconfigurability and thus improving supply chain strategic performance. They are visibility for sensing, visibility for learning, visibility for coordinating, and visibility for integrating. The results show that visibility for sensing has direct impact on supply chain strategic performance. Empirical evidence also supports that visibility for learning, visibility for coordinating, and visibility for integrating are important for enhancing supply chain reconfigurability, thus creating strategic value in supply chains. Supply chain visibility therefore enables firms to reconfigure their supply chain resources for greater competitive advantage. Implications of the results regarding the nature and the role of supply chain visibility in enhancing supply chain strategic performance are provided.