运用抽象技术和JPF生成类测试用例方法

从类的源代码中抽象出类的所有状态来减少系统状态及其行为,根据抽象后的类状态,设置JPF搜索环境,裁剪类方法测试序列生成时的搜索分支,提出了一种类测试用例生成方法。实验结果表明,该方法能够有效地减少类测试用例生成时间。     

An automatic abstraction technique for verifying featured,parameterised systems

A general technique combining model checking and abstraction is presented that allows property based analysis of systems consisting of an arbitrary number of featured components. We show how parameterised systems can be specified in a guarded command form with constraints placed on variables which occur in guards. We prove that results that hold for a small number of components can be shown to scale up. We then show how featured systems can be specified in a similar way, by relaxing constraints on guards. The main result is a generalisation theorem for featured systems which we apply to two well known examples.     

A controlled empirical evaluation of a requirements abstraction model

Requirement engineers in industry are faced with the complexity of handling large amounts of requirements as development moves from traditional bespoke projects towards market-driven development. There is a need for usable and useful models that recognize this reality and support the engineers in a continuous effort of choosing which requirements to accept and which to dismiss off hand using the goals and product strategies put forward by management. This paper presents an evaluation of such a model that is built based on needs identified in industry. The evaluation’s primary goal is to test the model’s usability and usefulness in a lab environment prior to large scale industry piloting, and is a part of a large technology transfer effort. The evaluation uses 179 subjects from three different Swedish Universities, which is a large portion of the university students educated in requirements engineering in Sweden during 2004 and 2005. The results provide a strong indication that the model is indeed both useful and usable and ready for industry trials.     

多视频摘要技术:方法、应用及挑战

多视频摘要技术近年来受到了国内外学者的广泛关注,它是指通过对视频结构和内容的分析,从多个相关视频文件中提取出有意义的部分,将它们以一定方式进行组合,形成简洁的、能够充分表现语义内容的概要,目的是提供快捷的浏览和查询服务。目前该技术还处于起步阶段,实际的应用系统很少,有关体系结构、技术方法仍需要深入研究,更多的应用方向还有待开拓。在介绍研究意义的基础上,对多视频摘要的研究现状和主要方法进行了归纳、评述,探讨了一些应用方向,指出了目前研究面临的重点问题以及发展趋势。     

Model abstraction and inclusion principle: a comparison

This paper discusses connections between the inclusion principle and model abstraction in large-scale hierarchical control systems. It also provides conditions for implementation of controllability and observability in linear continuous-time dynamic systems satisfying either aggregation or restriction conditions, as well as for observability implementation in linear continuous-time dynamic systems satisfying conditions for abstraction     

Infopipes: An abstraction for multimedia streaming

To simplify the task of building distributed streaming applications, we propose a new abstraction for information flow – Infopipes. Infopipes make information flow primary, not an auxiliary mechanism that is hidden away. Systems are built by connecting predefined component Infopipes such as sources, sinks, buffers, filters, broadcasting pipes, and multiplexing pipes. The goal of Infopipes is not to hide communication, like an RPC system, but to reify it: to represent communication explicitly as objects that the program can interrogate and manipulate. Moreover, these objects represent communication in application-level terms, not in terms of network or process implementation.     

Extension of the Steiglitz and McBride identification technique

The Steiglitz and McBride identification technique was orginally developed for data containing uncorrelated noise in the output. A way of adopting this technique to correlated noise is presented here. It is also shown that the technique can be used for data containing noise in the input.     

Sigiri: uniform resource abstraction for grids and clouds

With the maturation of grid computing facilities and recent explosion of cloud computing data centers, midscale computational science has more options than ever before to satisfy computational needs. But heterogeneity brings complexity. We propose a simple abstraction for interaction with heterogeneous resource managers spanning grid and cloud computing and on features that make the tool useful for the midscale physical or natural scientist. Key strengths of the abstraction are its support for multiple standard job specification languages, preservation of direct user interaction with the service, removing the delay that can come through layers of services, and the predictable behavior under heavy loads. Copyright © 2012 John Wiley & Sons, Ltd.     

Information modelling: foundation, abstraction mechanisms and approach

This paper briefly presents a new information modelling methodology useful as an information systems development approach. The methodology is based on a set of fundamental abstraction mechanisms which provide the means for modelling on a number of abstraction levels and, on the highest levels, the most invariant components and structures of the information model can be identified and defined. It is also based on the object-oriented paradigm which is applied in harmony with the abstraction mechanisms. The methodology introduces an alternative to the traditional entity relationship technique with respect to modelling of information and on this basis it can support efforts to construct reusable, extensible and reliable information systems.     

A flexible real-time scheduling abstraction: design and implementation

An evolution is happening in the way that operating systems support the real-time requirements of their applications. The need to run real-time applications such as multimedia in the same environment as complex non-real-time servers and applications has motivated much interest in restructuring existing operating systems. Many issues related to thread scheduling and synchronization have been investigated. However, little consideration has been given to the flexibility and modularity required in the support of application-level scheduling needs, although it is well known that application requirements are diverse. In this paper, we describe a real-time scheduling abstraction which provides modularity and flexibility to the scheduling support of operating systems. Our design has been implemented using the Mach 3.0 kernel and a locally developed multiprocessor kernel (the r-kernel) as development platforms. © 1997 John Wiley & Sons, Ltd.     

WorkCrews: An abstraction for controlling parallelism

In implementing parallel programs, it is important to find strategies for controlling parallelism that make the most effective use of available resources. In this paper, we introduce a dynamic strategy called WorkCrews for controlling the use of parallelism on small-scale, tightly-coupled multiprocessors. In the WorkCrew model, tasks are assigned to a finite set ofworkers. As in other mechanisms for specifying parallelism, each worker can enqueue subtasks for concurrent evaluation by other workers as they become idle. The WorkCrew paradigm has two advantages. First, much of the work associated with task division can be deferred until a new worker actually undertakes the subtask and avoided altogether if the original worker ends up executing the subtask serially. Second, the ordering of queue requests under WorkCrews favors coarse-grained subtasks, which reduces further the overhead of task decomposition.Mark Vandevoorde's work in this project was supported in part by the Advanced Research Projects Agency of the Department of Defense, monitored by the Office of Naval Research under contract N00014-83-K-0125; Digital Equipment Corporation's Systems Research Center; the National Science Foundation under Grant 8706652-CCR; and the NYNEX Corporation. Current address: Laboratory for Computer Science, Massachusetts Institute of Technology.Digital Equipment Corporation, Systems Research Center.     

MeterPU: a generic measurement abstraction API

We present MeterPU, an easy-to-use, generic and low-overhead abstraction API for taking measurements of various metrics (time, energy) on different hardware components (e.g., CPU, DRAM, GPU) in a heterogeneous computer system, using pluggable platform-specific measurement implementations behind a common interface in C++. We show that with MeterPU, not only legacy (time) optimization frameworks, such as autotuned skeleton back-end selection, can be easily retargeted for energy optimization, but also switching between measurement metrics or techniques for arbitrary code sections now becomes trivial. We apply MeterPU to implement the first energy-tunable skeleton programming framework, based on the SkePU skeleton programming library.     

Selective image abstraction

We present a novel and convenient method for producing selective stylized simplification of images. The user uses a brush to interactively mark certain areas of the input image which are to be left unaltered. Boundaries of these areas are then automatically optimized to underlying object boundaries in the image. Our method then performs stylized simplification of the unmarked areas, while preserving the marked areas. The method ensures a smooth transition between stylized and unaltered regions to leave a mixed reality image which combines the real and the abstract. Stylized simplification is performed using nonlinear diffusion, which can generate sophisticated results. We modify the classic model of nonlinear diffusion to incorporate bilateral filtering; we apply diffusion speed control of each pixel based on the user’s input. The level of simplification can be controlled intuitively based on the diffusion time; another parameter controls the abstraction style, giving a simple and intuitive user interface. Our contributions include a simple-to-use method to produce a novel NPR style and a modified nonlinear diffusion model suited to this selective stylized simplification task. Experimental results show that the final mixed reality results are harmonious.     

Finger-vein pattern identification using SVM and neural network technique

This paper presents a support vector machine (SVM) technique for finger-vein pattern identification in a personal identification system. Finger-vein pattern identification is one of the most secure and convenient techniques for personal identification. In the proposed system, the finger-vein pattern is captured by infrared LED and a CCD camera because the vein pattern is not easily observed in visible light. The proposed verification system consists of image pre-processing and pattern classification. In the work, principal component analysis (PCA) and linear discriminant analysis (LDA) are applied to the image pre-processing as dimension reduction and feature extraction. For pattern classification, this system used an SVM and adaptive neuro-fuzzy inference system (ANFIS). The PCA method is used to remove noise residing in the discarded dimensions and retain the main feature by LDA. The features are then used in pattern classification and identification. The accuracy of classification using SVM is 98% and only takes 0.015 s. The result shows a superior performance to the artificial neural network of ANFIS in the proposed system.     

Continuous-time model identification from sampled data: Implementation issues and performance evaluation

This paper deals with equation error methods that fit continuous-time transfer function models to discrete-time data recently included in the CONTSID (CONtinuous-Time System IDentification) Matlab toolbox. An overview of the methods is first given where implementation issues are highlighted. The performances of the methods are then evaluated on simulated examples by Monte Carlo simulations. The experiments have been carried out to study the sensitivity of each approach to the design parameters, sampling period, signal-to-noise ratio, noise power spectral density and type of input signal. The effectiveness of the CONTSID toolbox techniques is also briefly compared with indirect methods in which discrete-time models are first estimated and then transformed into continuous-time models. The paper does not consider iterative or recursive algorithms for continuous-time transfer function model identification.     

Parameter identification technique for multivariate stochastic systems

This paper considers the problem of obtaining accurate estimates of multivariate systems with reasonable computations. To avoid the structural identification problem which is associated with multivariate systems, we observe the system by a linear combination of the outputs. The two stage least square method is employed to estimate the model parameters. An optimum combination of the outputs is obtained such that the parameter estimates have the least asymptotic generalized variance. Computer simulations are provided to illustrate the usefulness of the proposed method.     

LLAMA: The low-level abstraction for memory access

The performance gap between CPU and memory widens continuously. Choosing the best memory layout for each hardware architecture is increasingly important as more and more programs become memory bound. For portable codes that run across heterogeneous hardware architectures, the choice of the memory layout for data structures is ideally decoupled from the rest of a program. This can be accomplished via a zero-runtime-overhead abstraction layer, underneath which memory layouts can be freely exchanged. We present the low-level abstraction of memory access (LLAMA), a C++ library that provides such a data structure abstraction layer with example implementations for multidimensional arrays of nested, structured data. LLAMA provides fully C++ compliant methods for defining and switching custom memory layouts for user-defined data types. The library is extensible with third-party allocators. Providing two close-to-life examples, we show that the LLAMA-generated array of structs and struct of arrays layouts produce identical code with the same performance characteristics as manually written data structures. Integrations into the SPEC CPU^® lbm benchmark and the particle-in-cell simulation PIConGPU demonstrate LLAMA's abilities in real-world applications. LLAMA's layout-aware copy routines can significantly speed up transfer and reshuffling of data between layouts compared with naive element-wise copying. LLAMA provides a novel tool for the development of high-performance C++ applications in a heterogeneous environment.     

Priority and abstraction in process algebra

More than 15 years ago, Cleaveland and Hennessy proposed an extension of the process algebra CCS in which some actions may take priority over others. The theory was equipped with a behavioral congruence based on strong bisimulation.This article gives a full account of the challenges in, and the solutions employed for, defining a semantic theory of observation congruence for this process algebra. A full-abstraction result is presented whose proof relies on a novel approach based on successive approximations for identifying the largest congruence contained in an intuitive but naïve equivalence. Prioritized observation congruence is also characterized equationally for the class of finite processes, while its utility for system verification is demonstrated by an illustrative example.