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1.
Businesses are undergoing a major paradigm shift, moving from traditional management into a world of agile organizations and processes. An agile corporation should be able to rapidly respond to market changes. For this reason, corporations have been seeking to develop numerous information technology (IT) systems to assist with the management of their business processes. Many of the coming new business processes may contain embedded intelligent agent-based systems. Agent technology looks set to radically alter not only the way in which computers are interacted, but also the way complex processes, e.g., product development, are conceptualized and built. The paper presents a fuzzy approach based on an intelligent agent framework to develop modular products. This approach aims to address the research issue: "How can modular design be carried out through intelligent agents to meet a customer's fuzzy requirements using modules that come from suppliers that are geographically separated and operate on differing computer platforms?" The proposed methodology is applied to a real-world case that involves module-based synthesis at one of largest distribution centers in the world  相似文献   

2.
A generic rendering system   总被引:3,自引:0,他引:3  
Describes the software architecture of a rendering system that follows a pragmatic approach to integrating and bundling the power of different low-level rendering systems within an object-oriented framework. The generic rendering system provides higher-level abstractions to existing rendering systems and serves as a framework for developing new rendering techniques. It wraps the functionality of several widely-used rendering systems, defines a unified object-oriented application programming interface and provides an extensible, customizable apparatus for evaluating and interpreting hierarchical scene information. As a fundamental property, individual features of a specific rendering system can be integrated into the generic rending system in a transparent way. The system is based on a state machine, called an "engine", which operates on "rendering components". Four major categories of rendering components constitute the generic rendering system: "shapes" represent geometries, "attributes" specify properties assigned to geometries and scenes, "handlers" encapsulate rendering algorithms, and "techniques" represent evaluation strategies for rendering components. As a proof of concept, we have implemented the described software architecture using the Virtual Rendering System, which currently wraps the functionality of the OpenGL, Radiance, POV Ray and RenderMan systems  相似文献   

3.
基于框架的面向对象开发技术是实现大规模软件复用的一种有效的途径.由于框架本身层次的复杂性,往往导致框架实例化过程的复杂和烦琐,通常采用记录框架变化点的实例化过程和约束条件的方法来解决这个问题.但是,对于那些缺乏详细记录的"遗留"面向对象框架,框架变化点实例化记录往往隐含在具体的实现细节中,从而使得"遗留"面向对象框架的复用变得十分困难.提出了一种基于版本信息获取面向对象框架的实例化模式的方法,从而辅助框架的实例化工作.  相似文献   

4.
5.
基于构件的软件框架与角色扩展形态研究   总被引:48,自引:2,他引:48       下载免费PDF全文
刘瑜  张世琨  王立福  杨芙清 《软件学报》2003,14(8):1364-1370
框架是实现大粒度软件复用的有效途径,面向对象框架可以通过实例化扩展实现具体的应用系统,但是,研究和实践表明,面向对象框架存在着一些问题.采用基于构件的框架(CBSF),通过用构件替代框架内部相互协作的类,以增大框架构成成分的粒度;同时利用构件的接口调用和组装实现框架扩展机制.主要探讨了角色扩展形态,角色是将要被进一步实例化的特殊构件,可分为抽象构件和模板.针对不同变化性类型,提出可以利用体系结构模式、设计模式或参数化这3种方式设计CBSF角色扩展,进而讨论了基于角色扩展形态的应用构件组装.  相似文献   

6.
随着实时系统在时间关键和安全关键的行业的广泛应用,程序的时间属性受到越来越广泛的关注. Henzinger提出了LET(Logical Execution Time)编程模型,提供了明确描述时间属性的机制,确保了系统的时间确定性.但传统的实时操作系统模型采用了与LET截然不同的抽象,难以很好地支持LET编程模型. Minicore是一种新型操作系统模型,程序由一组内部没有同步点的服务组成,具有较好的时间确定性和可控性,与LET编程模型的思想更吻合.将LET的控制模型和Minicore的运行模型相结合,可形成一种具有时间确定性的新型编程框架.主要描述了该框架的内存管理机制的设计和实现.文末以智能小车控制系统的实现作为研究实例验证本系统的可行性.  相似文献   

7.
. An object-oriented (OO) framework for Partial Differential Equations (PDEs) provides software abstractions for numerical simulation of PDEs. The design of such frameworks is not trivial, and the outcome of the design is highly dependent on which mathematical abstractions one chooses to support. In this paper, coordinate free abstractions for PDEs are advocated. The coordinate free formulation of a PDE hides the underlying coordinate system. Therefore, software based on these concepts has the prospect of being more modular, since the PDE formulation is separated from the representation of the coordinates. Use of coordinate free methods in two independent OO frameworks are presented, in order to exemplify the viability of the concepts. The described applications simulate seismic waves for various classes of rock models and the incompressible Navier-Stokes equations on curvi-linear grids, respectively. In both cases, the possibility to express the equations in a domain independent fashion is crucial. Similarities and differences between the two coordinate free frameworks are discussed. A number of places where such frameworks should be designed for modification is identified. This identification is of interest both for framework developers and for tentative framework users. ID="A1"Correspondance and offprint requests to: K Ahlander, Dept of Information Technology, University of Uppsala, Box 337, SE-75105 Uppsala, Sweden. E-mail: krister@tdb.uu.se  相似文献   

8.
Achieving efficient software implementations requires a great deal of knowledge, intelligence, and expertise on the part of programmers. One way to enhance software productivity is to incorporate the knowledge and skills of expert programmers into software synthesis systems to automate software development processes. Although many software synthesis systems have been developed, automatic control of synthesis remains a difficult problem. Understanding the role of expertise in software synthesis, and making it more explicit, can help us not only to gain autonomy in controlling the synthesis processes but also to better justify the design, implementations, selection of data structures or algorithms employed in constructing code. Our project aims at making synthesis as autonomous as possible by advances in intelligent control mechanisms to reduce user interaction in the synthesizer. In our earlier work, a blackboard control framework for controlling synthesis processes was introduced. This paper describes how the control framework language was designed and how knowledge in the knowledge bases of the framework was acquired and constructed. We present an example that shows how programming expertise can be used to increase the degree of autonomy in synthesis control, in particular by automating the selection of an appropriate data structure implementation.  相似文献   

9.
The consistency problems in UML models and related software processes can be very complex. First, although UML supports a modeling process that should yield inter and intraconsistent models, the meaning of the UML dependencies and their specializations is not precisely defined and, for this reason, many inconsistencies may appear in their models and processes. Precise definitions would form a basis for methods to detect and analyze consistency problems related to UML dependencies and relationships, as well as problems related to software processes described in UML. In addition, we are using the UML object constraint language (OCL) to describe constraints related to the framework instantiation process. OCL is recognized as a limited language in some aspects for expressing well-formedness rules. We have presented a method (T.C. Oliveira et al., 2004) that works in the case of consistent rules and consistent instantiation processes.  相似文献   

10.
In this paper, a proposal of a generic framework for process-oriented software development organizations is presented. Additionally, the respective way of managing the process model, and the instantiation of their processes with the Rational Unified Process (RUP) disciplines, whenever they are available, or with other kind of processes is suggested. The proposals made here were consolidated with experiences from real projects and we report the main results from one of those projects.  相似文献   

11.
Scsh, the Scheme shell, enables concurrent system programming with portable user-level threads. In scsh, threads behave like processes in many ways: each thread receives its own set of process resources; like Unix processes, new threads can inherit resources from the creating thread. The combination of scsh's interface to the POSIX API with user-level threads creates a number of design and implementation challenges: Scsh's abstractions for managing process resources raise interesting modularity issues, particularly in connection with first-class continuations. Scsh also provides an interface to the fork system call; its implementation must avoid common pitfalls that arise with a user-level thread system. This paper describes the design and implementation of the relevant abstractions and discusses the implications for programming-language and system design.  相似文献   

12.
To appropriately utilize the rapidly growing amount of data and information is a big challenge for people and organizations. Standard information retrieval methods, using sequential processing combined with syntax-based indexing and access methods, have not been able to adequately handle this problem. We are currently investigating a different approach, based on a combination of massive parallel processing with case-based (memory-based) reasoning methods. Given the problems of purely syntax-based retrieval methods, we suggest ways of incorporating general domain knowledge into memory-based reasoning. Our approach is related to the properties of the parallel processing microchip MS160, particularly targeted at fast information retrieval from very large data sets. Within this framework different memory-based methods are studied, differing in the type and representation of cases, and in the way that the retrieval methods are supported by explicit general domain knowledge. Cases can be explicitly stored information retrieval episodes, virtually stored abstractions linked to document records, or merely the document records themselves. General domain knowledge can be a multi-relational semantic network, a set of term dependencies and relevances, or compiled into a global similarity metric. This paper presents the general framework, discusses the core issues involved, and describes three different methods illustrated by examples from the domain of medical diagnosis.  相似文献   

13.
We outline an approach to construction of software libraries in which generic algorithms (algorithmic abstractions) play a more central role than in conventional software library technology or in the object-oriented programming paradigm. Our approach is to consider algorithms first, decide what types and access operations they need for efficient execution, and regard the types and operations as formal parameters that can be instantiated in many different ways, as long as the actual parameters satisfy the assumptions on which the correctness and efficiency of the algorithms are based. The means by which instantiation is carried out is language dependent; in the C + + examples in this paper, we instantiate generic algorithms by constructing classes that define the needed types and access operations. By use of such compile-time techniques and careful attention to algorithmic issues, it is possible to construct software components of broad utility with no sacrifice of efficiency.  相似文献   

14.
The so-called "first generation" expert systems were rule-based and offered a successful framework for building applications systems for certain kinds of tasks. Spatial, temporal, and causal reasoning, knowledge abstractions, and structuring are among topics of research for "second generation" expert systems. It is proposed that one of the keys for such research is knowledge organization. Knowledge organization determines control structure design, explanation and evaluation capabilities for the resultant knowledge base, and has strong influence on system performance. We are exploring a framework for expert system design that focuses on knowledge organization, for a specific class of input data, namely, continuous, time-varying data (image sequences or other signal forms). Such data are rich in temporal relationships as well as temporal changes of spatial relations, and are thus a very appropriate testbed for studies involving spatio-temporal reasoning. In particular, the representation formalism specifies the semantics of the organization of knowledge classes along the relationships of generalization/specialization, decomposition/aggregation, temporal precedence, instantiation, and expectation-activated similarity. Á hypothesize-and-test control structure is driven by the class organizational principles, and includes several interacting dimensions of search (data-driven, model-driven, goal-driven temporal, and failure-driven search). The hypothesis ranking scheme is based on temporal cooperative computation, with hypothesis "fields of influence" being defined by the hypothesis' organizational relationships. This control structure has proven to be robust enough to handle a variety of interpretation tasks for continuous temporal data. A particular incarnation, the ALVEN system, for left ventricular performance assessment from X-ray image sequences, will be summarized in this paper.  相似文献   

15.
In order to design workflows in changing and dynamic environments, a flexible, correct, and rapid realization of models of the activity flow is required. In particular, techniques are needed to design workflows capable of adapting themselves effectively when exceptional situations occur during process execution. The authors present an approach to flexible workflow design based on rules and patterns developed in the framework of the WIDE project. Rules allow a high degree of flexibility during workflow design by modeling exceptional aspects of the workflow separately from the main activity flow. Patterns model frequently occurring exceptional situations in a generalized way by providing the designer with skeletons of rules and suggestions about their instantiation, together with indications on relationships with other rules, with the activity flow, and with related information. Pattern based design relies on a pattern catalog containing patterns to be reused and on a formal basis for specializing and instantiating available patterns  相似文献   

16.
In the development of large software systems, several synchronization points have to be passed successfully in order to achieve high-end user acceptance of the final system. In particular, the integration of conceptual design entities has turned out to be the most crucial step in software development. At this point, an explicit representation of the organizational knowledge, namely how the integration can be performed, is required. The overall organization of the integration of design entities is a set of knowledge, action (including communication), and time. The knowledge part comprises the integration procedure itself as well as the design entities. Actions are performed by the members of the project team (project leaders, developers). Each integration step has to be performed synchronized, so that each member of the development team knows concurrently the status of the integration procedure. All other individual design activities are usually performed asynchronously. According to the need for an explicit representation of the organizational knowledge for large software system design, this paper attempts tounderstand the nature of large software system integration and formallydescribes the coordination of a dispersed set of software developers. The organizational knowledge is represented by processes that occur in an asynchronous development environment. The design knowledge is assigned to logical formulas that are processed as exchanged messages among developers. Hence, the activities for integration are based on the transmission of messages. Time-critical events, such as the integration of a particular design entity into the final conceptual design of the software system, have to become common knowledge concurrently for all developers. This organizational constraint has been formalized in the communication model. Not only can the proposed framework be adapted to organizational changes in a flexible way, it can also be applied to any specific development strategy for the integration of conceptual design entities. Thus, such kind of formal communication models may provide a sound basis for cooperative CASE (computer-aided software engineering) tools.This work has been sponsored by the Max Kade Foundation, New York.  相似文献   

17.
Sahoo  Manas 《IT Professional》2009,11(6):16-22
Technology innovations have shaped the IT Industry since its inception. Adoption of a particular innovation is often a key survival factor: "fast followers" learn from others, monetize an innovation, and almost always make abnormal profits. Thus, the important question for IT professionals is, "How can I evaluate an emerging trend for its investment worthiness?" To answer this question, the author describes a diffusion of IT innovations framework that can evaluate emerging trends in the IT space. He also analyzed some current trends using this framework and suggests strategies for investing in them.  相似文献   

18.
基于构件的软件设计模型   总被引:20,自引:0,他引:20  
构件式软件设计是从根本上实施软件复用的重要途径.文中结合层次的面向对象设计结构,讨论了类属构件GRC的模型,该模型的建立从几方面反映了可复用构件的类属性和应用环境.论文就类属构件提出了用于软件设计的机制和例化过程.  相似文献   

19.
产品线工程是一种正在出现的软件工程范型,用于开发相同领域的类似产品.在介绍了产品线框架相关的概念之后,根据产品线生命周期的特点,提出了框架从低级框架渐变为高级框架的过程,并在此基础上描述了框架元模型;为了支持从这种渐变,在组件库的基础上建立了视图机制,即原始映射视图、频繁组件项集视图和组件关联视图.这种基于组件库的视图机制,可以指导用户在框架实例化中的组件选取决策,促进了框架的成熟,提高了组件库的复用性能.  相似文献   

20.
基于Struts—Spring—Hibernate框架的软件复用技术   总被引:2,自引:0,他引:2  
软件复用是一种由预先构建好的、为复用目的而设计的软件结构来建立或者组装软件系统的过程。采用“高内聚,低耦合”的成熟框架来进行软件开发,是这一过程的一个很好实践。本文在深入研究软件设计模式的基础上,对目前流行的基于Struts—Spring—Hibernate框架进行可复用软件开发技术进行分析和研究。  相似文献   

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