入侵检测语言的评估

入侵检测语言是入侵检测系统用于定义攻击场景的表示规范．提出一种比较和评估入侵检测语言的方法，该方法建立在一个可被证明是互斥和完备的分类基础上，并基于表达能力、表示简洁性、检测强度等三个测度．使用该方法可以对现有的各类检测语言表示攻击特征并进行推理的相对有效性进行评估，从而揭示出现有检测语言的缺陷和理想的入侵检测语言应具有的特性．     

A systematic review of tools,languages, and methodologies for mashup development

Web 2.0 has become a powerful means of transmitting information in a number of fields, such as communication, e‐commerce, and entertainment. Nowadays, companies and organizations transmit specific information through different mechanisms, such as Web feeds and Web services. These data sources enable third parties to incorporate data from service providers into their own applications. On the basis of this understanding, mashups have emerged as a new approach to develop applications and which combine data and resources from heterogeneous sources—such as internal data sources, Web feeds, screen scraping, and Web services—with the aim of solving specific needs. Mashup development involves activities such as accessing heterogeneous sources, combining data from different data sources, and building graphical interfaces. These activities restrict the development of these kinds of applications only to experienced computer users. Today, a number of tools and programming languages are used to help carry out some of the aforementioned activities. These tools and programming languages have features enabling the integration of different technologies in order to solve problems such as data management from different data sources and content publication. If this is taken into account, there is a growing need to learn about the features, advantages, and disadvantages of these tools and programming languages in order to select the tool or language that best fits a specific need and a specific level of knowledge and experience in terms of software development. This paper presents a systematic review and analysis of the tools, programming languages, and software development methodologies involved in mashup development in order to learn more about the features and services provided by mashups. Furthermore, this research also explains the qualitative and quantitative evaluation used for the mashup development tools. The evaluation was performed in order to measure not only the usability of these tools but also the support that they provide for standardized features of Web development that they provide. Finally, new trends in the development of mashups are discussed. Copyright © 2013 John Wiley & Sons, Ltd.     

Parallel programming with logic languages: A survey

Formal properties of logic languages are largely studied; however, their impact on the practice of software design and programming is currently minimal. In this paper we survey some interesting representatives of the family of logic languages aiming at comparing the different capabilities they offer for designing and programming parallel systems. The logic languages Prolog, Aurora, Flat Concurrent Prolog, Parlog, GHC, and DeltaProlog were chosen, because a suitable set of relevant examples has been published, mostly by the language designers themselves. A number of sample programs is used to expose and compare the languages with respect to their object oriented programming capabilities for multiprocess coordination, interprocess communication, and resource management. Special attention is devoted also to metaprogramming as well, seen as a useful technique for specifying and building the operating environments of the languages themselves. The paper ends with a discussion on positive and negative features found comparing these languages, and indicates some guidelines to be followed in the design of new logic languages.     

Timing Constraints of Real-Time Systems: Constructs for Expressing Them, Methods of Validating Them

This paper examines timing constraints as features of realtime systems. It investigates the various constructs required in requirements languages to express timing constraints and considers how automatic test systems can validate systems that include timing constraints. Specifically, features needed in test languages to validate timing constraints are discussed. One of the distinguishing aspects of three tools developed at GTE Laboratories for real-time systems specification and testing is in their extensive ability to handle timing constraints. Thus, the paper highlights the timing constraint features of these tools.     

Safety verification of Ada programs using software fault trees

The software fault-tree analysis technique is explained. It is then extended to allow its use on a more complex language involving such features as concurrency and exception handling. Ada is used as the example language because many safety-critical projects are using or planning to use Ada. It also contains complex, real-time programming facilities found in other languages used in these types of projects. Software fault-tree analysis uses failure-mode templates to generate the fault tree. The templates provided can be used to define the procedures for applying the technique to programs written in most other declarative languages. To explain the use of the templates an example Ada program, for a traffic-light-control system, is analyzed. The cost and practicality of the method and its implications for software reuse are assessed. The application of the safety analysis procedures to requirements modeling and specification languages is considered     

Pictorial Representation and Metaphor in Visual Language Design

This paper reports the results of seven different experiments, assessing the benefit that users gain from the inclusion of pictorial features such as pictorial metaphor, visual mnemonics or support for visual imagery in visual languages. The experiments are based on typical programming tasks such as problem solving, construction and interpretation. They employed a number of experimental languages, including both implicit pictorial representations and explicitly verbal metaphorical explanations. The results of these experiments indicate that special design considerations apply to visual languages. Direct application of Graphical User Interface metaphors does not result in automatic improvements in usability of visual languages for typical programming tasks. Visual languages can benefit from pictorial mnemonics, but systematic explanatory metaphors (whether visual or verbal) are less useful than consistent presentation of language abstractions.     

Advanced Features of Duration Calculus and Their Applications in Sequential Hybrid Programs

Duration Calculus was introduced as a logic to specify real-time requirements of computing systems. It has been used successfully in a number of case studies. Moreover, many variants were proposed to deal with various features of real time systems, including sequential communicating processes, sequential hybrid systems and imperative programming languages. This paper aims to integrate several variants of Duration Calculus, and to provide a semantic framework for real-time programming languages and sequential hybrid programs. A shortversion of this paper appeared in J. Davis, A.W. Roscoe and J.C.P. Woodcock editors, Millennial Perspectives in Computer Science,Proceedings of the 1999 Oxford-Microsoft Symposium in Honour ofProfessor C.A.R. Hoare.     

Mark scan garbage collection on a distributed architecture

In any computer architecture designed for the evaluation of declarative languages, efficient reclamation of redundant (garbage) storage is essential. High performance, exploiting the inherent parallelism of such languages, is now typically achieved by parallel architectures, computational graphs thus being distributed across many processing elements.This paper describes a real-time mark-scan garbage collection algorithm for a distributed machine with local store. The algorithm allows collection on a per-process basis, and several collections may run concurrently and asynchronously. Both non real-time and real-time versions are provided.It is hoped to publish implementation results for the algorithm when such are available.     

基于统计的汉英句子对齐研究

翻译比较规范的汉英语料适合用统计方法实现句子对齐．但评价函数中的参数计算不能采用处理印欧语种的方法，而要针对汉英语种的特点进行调整．在已有两种评价函数的基础上又提出五种评价函数，并进行了对比研究。     

Language and Gender Classification of Speech Files Using Supervised Machine Learning Methods

Many language identification (LID) systems are based on language models using techniques that consider the fluctuation of speech over time. Considering these fluctuations necessitates longer recording intervals to obtain reasonable accuracy. Our research extracts features from short recording intervals to enable successful classification of spoken language. The feature extraction process is based on frames of 20 ms, whereas most previous LIDs presented results based on much longer frames (3?s or longer). We defined and implemented 200 features divided into four feature sets: cepstrum features, RASTA features, spectrum features, and waveform features. We applied eight machine learning (ML) methods on the features that were extracted from a corpus containing speech files in 10 languages from the Oregon Graduate Institute (OGI) telephone speech database and compared their performances using extensive experimental evaluation. The best optimized classification results were achieved by random forest (RF): from 76.29% on 10 languages to 89.18% on 2 languages. These results are better or comparable to the state-of-the-art results for the OGI database. Another set of experiments that was performed was gender classification from 2 to 10 languages. The accuracy and the F measure values for the RF method for all the language experiments were greater than or equal to 90.05%.