多变体执行误报问题分析与解决方法综述

从安全角度出发,多变体执行（multi-variant execution,MVX）被广泛应用于网络安全防御,但多变体执行存在一个共性问题：即各路执行体向裁决器返回内容时,合路产生的误报难以解决。排除机器环境等客观因素,产生误报是因为表决器收到合路信息后开始对非一致变量作安全判断,除真实攻击造成的非一致变量外,还夹杂着正常系统运行产生的非一致变量（如内存描述符、端口号、随机数、代码及进程内的线程调用顺序）,从而造成表决器误判,影响多变体系统正常运行。如果能降低多变体执行的误报率,则可以有效地提高系统效率及防御能力。对近年来多变体执行的类型进行归类,并对多变体执行产生的误报问题及解决策略进行归纳总结,分析多变体执行产生裁决误报的原因,选择Pina算法进行同步的策略、编译器模块插桩的策略、缩小表决边界的策略,对三种方案在特定应用场景下进行实验分析,分析每个方法的功能及性能,指出各自策略的优点及缺点。最后讨论现有多变体执行现有技术未解决的难点和未来的研究方向。     

一个面向对象软件自动测试框架的设计和实现

介绍了一个测试用例驱动的面向对象软件自动化测试框架(简称为TCDA).TCDA使用UML作为形式化的分析和设计规格说明,从UML的体系结构视图中自动获取测试用例,并以XML的形式保存这些测试用例.TCDA可以根据具体编程语言,将测试用例翻译成由一系列源文件组成的测试脚本.测试执行过程中,测试脚本首先会被编译和链接,生成可执行文件,接着这些可执行文件将被运行,同时测试结果将被记录和分析,并最终生成一个结果分析报告.TCDA的原型系统使用Java实现.该系统包括测试配置、测试用例生成、测试脚本生成、测试执行和结果分析五个模块,分别支持以上描述的过程.     

基于模式分析的特征交互检测

旨在提出一种基于模式分析的特征交互检测方法,其基本思想在于从已知的交互中提取具有共性的冲突模式,并以之检测新的特征交互.该方法使用一组谓词公式描述交互发生的条件,使用Java语言对系统建模,借助于一个外部工具,系统模型可以遍历所有的运行场景.在模型运行期间,所有特征的行为将被收集和分析,一旦发现某个交互的条件得到满足,即产生冲突报告.该方法被用于一个E-mail系统的分析.实验结果显示,在处理了超过100万个运行场景后,该方法能够有效地检测出已知和未知的特征交互.     

信息抽取系统中多语种自然语言接口的研究

简要介绍了针对特定领域的多语种信息抽取系统的基本模型，并针对该系统的查询模块的需要，提出了一种结合基于实例推理和多智能主体技术的多语种自然语言接口的实现方法。总结了本方法的适用环境。     

Some features of a real-time BASIC executive

A real-time BASIC executive has been developed for process measurement and control. This paper describes two features of the executive which demonstrate that some of BASIC'S constraints are unnecessarily restrictive. The first feature permits alterations to a running program to be made on-line. Either statements or commands can be entered. This provides a powerful debugging tool and enables an extended command language to be implemented with minimal effort. The second feature provides a number of documentation aids. These include variable names of unrestricted length and end-of-line comments. The implementation of these facilities is described and examples of their use are given. It is shown that neither of the features is extravagant in its demands on either memory space or execution time. The features are therefore of interest for their simplicity and economy as well as their utility.     

CAPS: a computer-based aid to aircraft project studies

CAPS (Computer Aided Project Study) is a computer based system which has been developed to assist engineers and designers engaged in aircraft project studies. It has a modular organization encompassing a wide range of topics including mass, aerodynamics, performance and cost estimation.The data flow and module execution is controlled by the PROTRAN system which has been specially developed for CAPS but has other potential applications. Jobs are specified in simple statements using the PROTRAN language. People without programming knowledge rapidly become proficient in its use, but Fortran programmers can use all their experience since it is an extension of that language.This paper describes the development of CAPS and is illustrated by some practical examples. The main features of the PROTRAN system are also presented.     

Person Browser System Based on Named Entity Recognition for Broadcast News Interview Videos

This work introduces a novel approach to extract meaningful content information from video by collaborative integration of image understanding and natural language processing. We developed a person browser system that associates faces and overlaid name texts in videos. This approach takes news videos as a knowledge source, then automatically extracts face and assoicated name text as content information. The proposed framework consists of the text detection module, the face detection module, and the person indexing database module. The successful results of person extraction reveal that the proposed methodology of integrated use of image understanding techniques and natural language processing technique is headed in the right direction to achieve our goal of accessing real content of multimedia information.

     

Using target-language information to train part-of-speech taggers for machine translation

Although corpus-based approaches to machine translation (MT) are growing in interest, they are not applicable when the translation involves less-resourced language pairs for which there are no parallel corpora available; in those cases, the rule-based approach is the only applicable solution. Most rule-based MT systems make use of part-of-speech (PoS) taggers to solve the PoS ambiguities in the source-language texts to translate; those MT systems require accurate PoS taggers to produce reliable translations in the target language (TL). The standard statistical approach to PoS ambiguity resolution (or tagging) uses hidden Markov models (HMM) trained in a supervised way from hand-tagged corpora, an expensive resource not always available, or in an unsupervised way through the Baum-Welch expectation-maximization algorithm; both methods use information only from the language being tagged. However, when tagging is considered as an intermediate task for the translation procedure, that is, when the PoS tagger is to be embedded as a module within an MT system, information from the TL can be (unsupervisedly) used in the training phase to increase the translation quality of the whole MT system. This paper presents a method to train HMM-based PoS taggers to be used in MT; the new method uses not only information from the source language (SL), as general-purpose methods do, but also information from the TL and from the remaining modules of the MT system in which the PoS tagger is to be embedded. We find that the translation quality of the MT system embedding a PoS tagger trained in an unsupervised manner through this new method is clearly better than that of the same MT system embedding a PoS tagger trained through the Baum-Welch algorithm, and comparable to that obtained by embedding a PoS tagger trained in a supervised way from hand-tagged corpora.     

一种QL脚本的解析模块的分析研究

作为MapReduce系统的核心组件的脚本解析模块,它是分布式云计算平台实现的基础。该模块的实现是基于脚本编程接口,在此过程中使用的语言是QL（Query Language）。QL脚本通过脚本解析模块实现解析之后,事件执行模块则由参数通过配置事件的方式一一实现。下面就这种脚本语言的实现过程作了详细的分析。     

基于多媒体技术的认知功能评估系统之研究

基于多媒体技术,结合MSP430,设计了一款交互式的认知功能评估系统,该系统主要由MSP430微控制器、电磁感应模块、3轴传感器、LCD和无线通信模块组成。开发了包括命名、记忆、注意、抽象、定向、执行的6类游戏来评估大脑认知功能。实验中使用科技接受模型对系统进行评估（满分为7分,从“非常不同意”到“非常同意”分数依次增加）,其中使用意愿得分6.52分、娱乐性得分6.45分。实验结果表明：正常老人和轻度认知障碍老人相比,游戏执行时间更短（平均相差27.26 s）、准确率更高（平均相差4.38%）、数字记忆广度更好（平均相差0.7分）。     

Issues in the Design and Control of Parallel Rule-Firing Production Systems

The parallel execution of rules in a production system provides the potential for faster execution, but increases the complexity of control and design issues. We address two issues: controlling the execution of productions without introducing serial bottlenecks and maintaining correctness during the course of simultaneous rule executions. Two novel rule-firing policies are described: an asynchronous rule-firing policy that causes rules to be executed as soon as they become enabled and a task-based scheduler that allows multiple independent tasks to run asynchronously with respect to each other while allowing rules to execute either synchronously or asynchronously within the context of each task. Previous research in parallel rule-firing systems has indicated that a serializable result cannot be guaranteed without a run-time mechanism for detecting potentially harmful rule interactions. Our analysis of such mechanisms indicates that their overhead is prohibitive for asynchronous rule-firing systems. In exchange for improved performance, we trade the guarantee of serializability for the somewhat weaker claim that correct parallel rule-firing programs may be designed, given the appropriate language mechanisms. We present a simple locking scheme for working memory, which, when coupled with the appropriate language idioms, allows serializable programs to be developed without incurring the expense of run-time interference detection. The experimental results of this research are presented in the context of UMass Parallel OPS5, a rule-based language that incorporates parallelism at the rule, action, and match levels, and provides language constructs for supporting the design of parallel rule-based programs. Results are presented for a number of programs illustrating common AI paradigms including search, inference, and constraint satisfaction problems.     

An interactive software tool for system identification

The paper describes the conceptual basis, main features and functionality of an interactive software tool developed in support of system identification education and discovery. This Interactive Tool for System Identification Education (ITSIE) has been developed using Sysquake, a Matlab-like language with fast execution and excellent facilities for interactive graphics, and is deliverd as a stand-alone executable that is readily accessible to students and engineers. ITSIE provides two distinct functional modes that are very useful from an educational and industrial point of view. The simulation mode enables the user to evaluate the main stages of system identification, from input signal design through model validation, simultaneously and interactively in one screen on a user-specified dynamical system. The real data mode allows the user to load experimental data obtained externally and identify suitable models in an interactive fashion. The interactive tool enables students and engineers in industry to discover a myriad of fundamental system identification concepts with a much lower learning curve than existing methods.     

Linux下自动化测试执行管理工具的设计与实现

测试自动化是提高软件测试效率的重要途径。尽管各种测试工具具有强大的执行功能,但没有对测试过程和测试资源进行有效的管理。设计并实现了一个Linux下的自动化测试执行管理工具,侧重于测试执行管理和测试资源管理,并详细阐述了其总体构架、模块设计和关键技术。     

Intelligent selection and retrieval of multiple time-oriented records

Time-oriented domains with large volumes of time-stamped information, such as medicine, security information and finance, require useful, intuitive intelligent tools to process large amounts of time-oriented multiple-subject data from multiple sources. We designed and developed a new architecture, the VISualizatIon of Time-Oriented RecordS (VISITORS) system, which combines intelligent temporal analysis and information visualization techniques. The VISITORS system includes tools for intelligent selection, visualization, exploration, and analysis of raw time-oriented data and of derived (abstracted) concepts for multiple subject records. To derive meaningful interpretations from raw time-oriented data (known as temporal abstractions), we use the knowledge-based temporal-abstraction method. A major task in the VISITORS system is the selection of the appropriate subset of the subject population on which to focus during the analysis. Underlying the VISITORS population-selection module is our ontology-based temporal-aggregation (OBTAIN) expression-specification language which we introduce in this study. The OBTAIN language was implemented by a graphical expression-specification module integrated within the VISITORS system. The module enables construction of three types of expressions supported by the language: Select Subjects, Select Time Intervals, and Get Subjects Data. These expressions retrieve a list of subjects, a list of relevant time intervals, and a list of time-oriented subjects’ data sets, respectively. In particular, the OBTAIN language enables population-specification, through the Select Subjects expression, by using an expressive set of time and value constraints. We describe the syntax and semantics of the OBTAIN language and of the expression-specification module. The OBTAIN expressions constructed by the expression-specification module, are computed by a temporal abstraction mediation framework that we have previously developed. To evaluate the expression-specification module, five clinicians and five medical informaticians defined ten expressions, using the expression-specification module, on a database of more than 1,000 oncology patients. After a brief training session, both user groups were able in a short time (mean = 3.3 ± 0.53 min) to construct ten complex expressions using the expression-specification module, with high accuracy (mean = 95.3 ± 4.5 on a predefined scale of 0 to 100). When grouped by time and value constraint subtypes, five groups of expressions emerged. Only one of the five groups (expressions using time-range constraints), led to a significantly lower accuracy of constructed expressions. The five groups of expressions could be clustered into four homogenous groups, ordered by increasing construction time of the expressions. A system usability scale questionnaire filled by the users demonstrated the expression-specification module to be usable (mean score for the overall group = 68), but the clinicians’ usability assessment (60.0) was significantly lower than that of the medical informaticians (76.1).     

Formal analysis of a space-craft controller using SPIN

The paper documents an application of the finite state model checker SPIN to formally analyze a multithreaded plan execution module. The plan execution module is one component of NASA's New Millennium Remote Agent, an artificial intelligence-based spacecraft control system architecture which launched in October of 1998 as part of the DEEP SPACE 1 mission. The bottom layer of the plan execution module architecture is a domain specific language, named ESL (Executive Support Language), implemented as an extension to multithreaded COMMON LISP. ESL supports the construction of reactive control mechanisms for autonomous robots and spacecraft. For the case study, we translated the ESL services for managing interacting parallel goal-and-event driven processes into the PROMELA input language of SPIN. A total of five previously undiscovered concurrency errors were identified within the implementation of ESL. According to the Remote Agent programming team, the effort has had a major impact, locating errors that would not have been located otherwise and, in one case, identifying a major design flaw. In fact, in a different part of the system, a concurrency bug identical to one discovered by this study escaped testing and caused a deadlock during an in-flight experiment, 96 million kilometers from Earth. The work additionally motivated the introduction of procedural abstraction in terms of inline procedures into SPIN     

Control flow and data flow oriented integration testing methods

The testing of modular software systems can be divided into a module testing phase and an integration testing phase. While module testing checks the modules separately, integration testing examines the use of interfaces in a modular system. Integration testing allows errors to be found which cannot be found by module testing. The aim of this paper is to propose a new approach to integration testing. The main principle is to transfer and adapt module testing methods to the level of integration testing. The approach is described for control flow and data flow oriented testing methods. To decrease the testing effort and increase the probability of finding errors, integration testing can be limited to statically detectable anomalous applications of interfaces. This is accomplished by the combination of static analysis with dynamic execution and by the possibility of using information already provided by the module tests. To find further test data to execute interfaces, symbolic execution is applied. One great advantage here is to prove whether statically determined interface anomalies can be dynamically executed and can therefore occur at all.     

两导航模块相对导航的研究

主要研究两个导航模块间的相对导航,并实现了两导航模块间相对位置的实时测量。讨论了不同坐标系下定位结果的互相转换。对导航模块输出数据进行了简要的分析,叙述了在Visual Studio编译环境下利用C#语言编写程序实现对定位数据的提取分析,并对两个模块定位信息处理从而实时计算出两个导航模块的相对位置信息。