Test generation from P systems using model checking

This paper presents some testing approaches based on model checking and using different testing criteria. First, test sets are built from different Kripke structure representations. Second, various rule coverage criteria for transitional, non-deterministic, cell-like P systems, are considered in order to generate adequate test sets. Rule based coverage criteria (simple rule coverage, context-dependent rule coverage and variants) are defined and, for each criterion, a set of LTL (Linear Temporal Logic) formulas is provided. A codification of a P system as a Kripke structure and the sets of LTL properties are used in test generation: for each criterion, test cases are obtained from the counterexamples of the associated LTL formulas, which are automatically generated from the Kripke structure codification of the P system. The method is illustrated with an implementation using a specific model checker, NuSMV.     

Real-time multiple people tracking using competitive condensation

The CONDENSATION (Conditional Density Propagation) algorithm has a robust tracking performance and suitability for real-time implementation. However, the CONDENSATION tracker has some difficulties with real-time implementation for multiple people tracking since it requires very complicated shape modelling and a large number of samples for precise tracking performance. Further, it shows a poor tracking performance in the case of close or partially occluded people. To overcome these difficulties, we present three improvements: First, we construct effective templates of people's shapes using the SOM (Self-Organizing Map). Second, we take the discrete HMM (Hidden Markov Modelling) for an accurate dynamical model of the people's shape transition. Third, we use the competition rule to separate close or partially occluded people effectively. Simulation results shows that the proposed CONDENSATION algorithm can achieve robust and real-time tracking in the image sequences of a crowd of people.     

信念修正的完全和可操作的方法

给出了命题逻辑上信念修正的两种可操作的完全方法.首先对R-演算的规则进行了修改,使得对任何一个极大协调的子集都通过这组规则得到.然后,给出了求得所有的极小不协调子集的一组规则.最后,给出一个过程,该过程能求得所有的极大协调子集.因为这两种方法都能求得所有的极大协调子集,所以把它们称为完全的.     

Extremum Search Methods and Multivariate Control System Synthesis

Control system design based on the mathematical theory of optimality so far exhibits two practical shortcomings. First, due to analytical difficulties it is not always possible to carry the solution to the end, especially in the case of nonlinear problems. Second, even if such a solution is obtained, it must necessarily be based on knowledge of the characteristics of the controlled plant. However, incomplete knowledge of such properties is the typical situation in control system design. This need not be a disadvantage, since the classical basis of control systems, i.e., the principle of feedback, allows one to largely overcome these difficulties, because a system with feedback can achieve the control objective even when the plant characteristics vary over a wide range.     

多Agent信念逻辑及其在概率意义下的推广

首先建立了一种多Agent信念逻辑MBL(multi-agentbelieflogic),在经典信念逻辑基础上增加了普遍信念算子和公共信念算子,给出MBL的Kripke语义与广义Aumann语义,讨论了两者的等价性,证明了MBL对于上述两种语义的可靠性和完备性.其次,建立了一种多Agent概率信念逻辑MPBL(multi-agentprobabilisticbelieflogic),通过在广义Aumann语义基础上引入概率空间,给出了MPBL的概率Aumann语义,证明了它的可靠性,并给出MPBL的一些推论.     

Nonmonotonic reasoning with multiple belief sets

In complex reasoning tasks it is often the case that there is no single, correct set of conclusions given some initial information. Instead, there may be several such conclusion sets, which we will call belief sets. In the present paper we introduce nonmonotonic belief set operators and selection operators to formalize and to analyze structural aspects of reasoning with multiple belief sets. We define and investigate formal properties of belief set operators as absorption, congruence, supradeductivity and weak belief monotony. Furthermore, it is shown that for each belief set operator satisfying strong belief cumulativity there exists a largest monotonic logic underlying it, thus generalizing a result for nonmonotonic inference operations. Finally, we study abstract properties of selection operators connected to belief set operators, which are used to choose some of the possible belief sets. This revised version was published online in June 2006 with corrections to the Cover Date.     

>维吾尔语广播新闻敏感词检索系统的研究

维吾尔语广播新闻敏感词检索系统是以HMM为基础。在MATLAB平台上设计实现的。该系统的特点包括 1.由于维吾尔语敏感词数量不多,该系统语音语料库很小。2.由于广播新闻中的发音较为标准规范,在识别中避免了说话人发音上的不规范,这有利于语音识别系统性能的提高。3.由于选择词素为识别基元,易于识别基元端点检测。     

Confluence operators and their relationships with revision,update and merging

In this paper we introduce confluence operators, that are inspired by the existing links between belief revision, update and merging operators. Roughly, update operators can be considered as pointwise revision, whereas revision operators can be considered as special case of merging operators. Confluence operators are to merging operators what update operators are to revision operators. Similarly, update operators can be considered as special case of confluence operators just as revision can be considered as special case of merging operators. Confluence operators gives all possible agreement situations from a set of belief bases.     

rStream: Resilient and Optimal Peer-to-Peer Streaming with Rateless Codes

Due to the lack of stability and reliability in peer-to-peer networks, multimedia streaming over peer-to-peer networks represents several fundamental engineering challenges. First, multimedia streaming sessions need to be resilient to volatile network dynamics and node departures that are characteristic in peer-to-peer networks. Second, they need to take full advantage of the existing bandwidth capacities by minimizing the delivery of redundant content and the need for content reconciliation among peers during streaming. Finally, streaming peers need to be optimally selected to construct high-quality streaming topologies so that end-to-end latencies are taken into consideration. The original contributions of this paper are twofold. First, we propose to use a recent coding technique, referred to as rateless codes, to code the multimedia bitstreams before they are transmitted over peer-to-peer links. The use of rateless codes eliminates the requirements of content reconciliation, as well as the risks of delivering redundant content over the network. Rateless codes also help the streaming sessions to adapt to volatile network dynamics. Second, we minimize end-to-end latencies in streaming sessions by optimizing toward a latency-related objective in a linear optimization problem, the solution to which can be efficiently derived in a decentralized and iterative fashion. The validity and effectiveness of our new contributions are demonstrated in extensive experiments in emulated realistic peer-to-peer environments with our rStream implementation.     

An algorithm on fairness verification of mobile sink routing in wireless sensor network

Congestion and starvation will occur among some nodes due to the emerging serious unfairness, which is derived from the limited communication capabilities of all nodes and sink or in the case of a mobile sink moving to a new place. The problem to be solved is to balance the network and keep the fairness for all nodes. For this purpose, this paper focuses on verifying the fairness of mobile sink routing based on both state and action, which is realized mainly by composing Labeled Kripke Transition Systems (LKTS). First, an approach is presented by LKTS to model node behaviors. Second, a notion of Fair Computational Tree Logic (CTL) is introduced to describe the fairness formulae in branching time transitions, and four kinds of fairness assumptions are defined for fairness verification. Moreover, in order to avoid the problem of state-space explosion, Bounded model Checking to explore states and transitions on-the-fly until a witness is found, while Strong Connected Components algorithm is used to pick up fair paths under fairness constraints of Fair CTL. The experimental results show the superiority of our method by the savings in memory and time consumptions during the mobile sink routing process.     

A sequence labeling model for catchphrase identification from legal case documents

In a Common Law system, legal practitioners need frequent access to prior case documents that discuss relevant legal issues. Case documents are generally very lengthy, containing complex sentence structures, and reading them fully is a strenuous task even for legal practitioners. Having a concise overview of these documents can relieve legal practitioners from the task of reading the complete case statements. Legal catchphrases are (multi-word) phrases that provide a concise overview of the contents of a case document, and automated generation of catchphrases is a challenging problem in legal analytics. In this paper, we propose a novel supervised neural sequence tagging model for the extraction of catchphrases from legal case documents. Specifically, we show that incorporating document-specific information along with a sequence tagging model can enhance the performance of catchphrase extraction. We perform experiments over a set of Indian Supreme Court case documents, for which the gold-standard catchphrases (annotated by legal practitioners) are obtained from a popular legal information system. The performance of our proposed method is compared with that of several existing supervised and unsupervised methods, and our proposed method is empirically shown to be superior to all baselines.

     

Improving validity and reliability in longitudinal case study timelines

Management Information Systems researchers rely on longitudinal case studies to investigate a variety of phenomena such as systems development, system implementation, and information systems-related organizational change. However, insufficient attention has been spent on understanding the unique validity and reliability issues related to the timeline that is either explicitly or implicitly required in a longitudinal case study. In this paper, we address three forms of longitudinal timeline validity: time unit validity (which deals with the question of how to segment the timeline – weeks, months, years, etc.), time boundaries validity (which deals with the question of how long the timeline should be), and time period validity (which deals with the issue of which periods should be in the timeline). We also examine timeline reliability, which deals with the question of whether another judge would have assigned the same events to the same sequence, categories, and periods. Techniques to address these forms of longitudinal timeline validity include: matching the unit of time to the pace of change to address time unit validity, use of member checks and formal case study protocol to address time boundaries validity, analysis of archival data to address both time unit and time boundary validity, and the use of triangulation to address timeline reliability. The techniques should be used to design, conduct, and report longitudinal case studies that contain valid and reliable conclusions.     

Evaluating Various Road Ownership Structures and Potential Competition on an Urban Road Network

Fundamental changes in road ownership and pricing have been viewed as possible remedies for the road usage and funding challenges in the transportation sector. To fill the gaps in our knowledge about the choice among different ownership structures, we develop a multi-level programming model that integrates system performance and profit maximization, game theory, and modified traffic assignment sub-models. Using this model, we provide a set of policy insights for policy makers. First, toll roads are interdependent in a complex manner since some pairs of roads are substitutes and others are complements, and because such cross effects can be reversed in different time periods and under different own and cross toll rates. Second, each toll road’s profit generally increases when more roads are tolled since roads commonly act as substitutes to each other. With such an insight, policy makers can ensure higher (and/or less risky) profits from toll roads and better deals with private operators of toll roads. Third, a mixture of private and public toll roads could generate significant profits while reducing transportation costs dramatically, thus contributing to sustainability. Finally, a comprehensive long-run transportation plan must investigate various road ownership schemes and examine their impacts on the profitability and the performance of the transportation system as a whole.     

Domain-knowledge-guided schema evolution for accounting database systems

The static meta-data view of accounting database management is that the schema of a database is designed before the database is populated and remains relatively fixed over the life cycle of the system. However, the need to support accounting database evolution is clear: a static meta-data view of an accounting database cannot support next generation dynamic environment where system migration, organization reengineering, and heterogeneous system interoperation are essential. This paper presents a knowledge-based approach and mechanism to support dynamic accounting database schema evolution in an object-based data modeling context. When an accounting database schema does not meet the requirements of a firm, the schema must be changed. Such schema evolution can be realized via a sequence of evolution operators. As a result, this paper considers the question: what heuristics and knowledge are necessary to guide a system to choose a sequence of operators to complete a given evolution task for an accounting database? In particular, we first define a set of basic evolution schema operators, employing heuristics to guide the evolution process. Second, we explore how domain-specific knowledge can be used to guide the use of the operators to complete the evolution task. A well-known accounting data model, REA model, is used here to guide the schema evolution process. Third, we discuss a prototype system, REAtool, to demonstrate and test our approach.     

SENFIS: a Sensor Node File System for increasing the scalability and reliability of Wireless Sensor Networks applications

In the last years the Wireless Sensor Networks’ (WSN) technology has been increasingly employed in various application domains. The extensive use of WSN posed new challenges in terms of both scalability and reliability. This paper proposes Sensor Node File System (SENFIS), a novel file system for sensor nodes, which addresses both scalability and reliability concerns. SENFIS can be mainly used in two broad scenarios. First, it can transparently be employed as a permanent storage for distributed TinyDB queries, in order to increase the reliability and scalability. Second, it can be directly used by a WSN application for permanent storage of data on the WSN nodes. The experimental section shows that SENFIS implementation makes an efficient use of resources in terms of energy consumption, memory footprint, flash wear levelling, while achieving execution times similarly with existing WSN file systems.     

基于半张量积的完备性阈值求解方法

为了精确地计算Kripke模型的完备性阈值,将半张量积引入到有界模型检测的完备性阈值的计算中,采用离散时间进化系统来研究Kripke模型的状态进化拓扑结构,提出了基于半张量积的有界模型检测完备性阈值的求解算法。通过实例说明了本方法能够求解Kripke模型的完备性阈值。结果表明利用矩阵采用代数方法能够精确地计算模型的前向半径。     

A simplified MMC model for the control of an arm with redundant degrees of freedom

The paper proposes a model for the control of a multisegmented arm with redundant degrees of freedom. On the basis of an earlier model, the so-called MMC net, a simplified version is proposed here which has several advantages. First, it can easily be scaled up for the 3D case. Second, for the linear version a complete convergence proof is possible. Third, the properties of the earlier model are unchanged, namely versatile control of the redundant system, immediate change from direct kinematics to inverse kinematics or any mixed control task, as well as robustness against singularities.     

基于置信规则库的应急方案调整方法

针对运用案例推理生成应急方案的问题,提出了一种基于置信规则库的方案调整方法．依据案例检索方法得到与目标案例最相似的历史案例,计算案例库中其他案例与最相似历史案例的问题差值,并转换为评价等级置信度形式;再利用历史案例信息及学习模型确定案例规则库的参数．在此基础上,将目标案例与最相似案例的问题差值转换为评价等级置信度形式,通过置信规则库的推理规则得到目标案例的方案．最后,通过一个环境突发事件的救援算例来说明该方法的可行性和有效性．     

空间元数据系统的研究与设计

本文介绍了空间元数据的基本概念，分析了空间元数据标准和空间元数据系统研究的现状和面临的困难，提出了一种有效的空间元数据系统模型，用于采集、管理、维护和发布空间元数据，并实现空间元数据的快速查询和准确定位。     

An investigation of modal structures as an alternative semantic basis for epistemic logics

In the past, Kripke structures have been used to specify the semantic theory of various modal logics. More recently, modal structures have been developed as an alternative to Kripke structures for providing the semantics of such logics. While these approaches are equivalent in a certain sense, it has been argued that modal structures provide a more appropriate basis for representing the modal notions of knowledge and belief. Since these notions, rather than the traditional notions of necessity and possibility, are of particular interest to artificial intelligence, it is of interest to examine the applicability and versatility of these structures. This paper presents an investigation of modal structures by examining how they may be extended to account for generalizations of Kripke structures. To begin with, we present an alternative formulation of modal structures in terms of trees; this formulation emphasizes the relation between Kripke structures and modal structures, by showing how the latter may be obtained from the former by means of a three-step transformation. Following this, we show how modal structures may be extended to represent generalizations of possible worlds, and to represent generalizations of accessibility between possible worlds. Lastly, we show how modal structures may be used in the case of a full first-order system. In all cases, the extensions are shown to be equivalent to the corresponding extension of Kripke structures.