ERP系统的组件化模型研究

对ERP系统的组件化进行了研究，提出了ERP系统的组件化模型框架，该模型框架由企业视图层、系统构架层、生命周期层3个维度组成。企业视图维给出了组件化的企业对象，系统构架维给出了ERP系统的组件化层次，生命周期维给出了组件化的实施过程。从软件复用的角度对模型框架进行了详细阐述。     

ALOCOM: a generic content model for learning objects

e-Learning organizations are focusing heavily on learning content reusability. The ultimate objective is a learning object economy characterized by searchable digital libraries of reusable learning objects that can be exchanged and reused across various learning systems. To enable such approach, basic questions of learning content interoperability need to be addressed. This paper investigates the interoperation of learning content defined according to different specifications. A number of content models are reviewed that define learning objects and their components. On the basis of a comparative analysis, the content models are mapped to a generic model for learning objects to address interoperability questions and to enable share and reuse on a global scale.     

Design process and data models to support the design of sustainable remanufactured products

The need for increased levels of reuse and remanufacturing is driving the need for sustainable design of remanufactured products. It is acknowledged that design for remanufacturing benefits the environment. However, it seldom integrates eco-design approaches as it requires ‘life cycle thinking’ with closed-loop life cycles. The objective of this paper is to support eco-design of remanufactured products with design process and data models structuring the activities to be performed and providing the support required. We consider the development of two activities in particular: definition of the target, and environmental analysis. The first activity exploits the concept of RPP (Remanufacturable Product Profile), building on the criteria that are crucial for a successful remanufactured product. The second one exploits the life cycle brick concept that associates each product component with a specific life cycle and related environmental impacts. The models proposed are exploited in a case study concerning the design of remanufactured truck gearboxes.     

Assessment and cross-product prediction of software product line quality: accounting for reuse across products,over multiple releases

The goals of cross-product reuse in a software product line (SPL) are to mitigate production costs and improve the quality. In addition to reuse across products, due to the evolutionary development process, a SPL also exhibits reuse across releases. In this paper, we empirically explore how the two types of reuse—reuse across products and reuse across releases—affect the quality of a SPL and our ability to accurately predict fault proneness. We measure the quality in terms of post-release faults and consider different levels of reuse across products (i.e., common, high-reuse variation, low-reuse variation, and single-use packages), over multiple releases. Assessment results showed that quality improved for common, low-reuse variation, and single-use packages as they evolved across releases. Surprisingly, within each release, among preexisting (‘old’) packages, the cross-product reuse did not affect the change and fault proneness. Cross-product predictions based on pre-release data accurately ranked the packages according to their post-release faults and predicted the 20 % most faulty packages. The predictions benefited from data available for other products in the product line, with models producing better results (1) when making predictions on smaller products (consisting mostly of common packages) rather than on larger products and (2) when trained on larger products rather than on smaller products.     

The Case for Frame-Based Software Engineering

Frame technology adapts generic components into custom information structures. Its facility for maximizing reuse and minimizing redundancy has demonstrated dramatic improvements across software's life cycle.     

Enhancing ISO/IEC 15288 with reuse and product management: An add-on process reference model

To support the transformation of system engineering from the project-based development of highly customer-specific solutions to the reuse and customization of ‘system products’, we integrate a process reference model for reuse- and product-oriented industrial engineering and a process reference model extending ISO/IEC 12207 on software life cycle processes with software- and system-level product management. We synthesize the key process elements of both models to enhance ISO/IEC 15288 on system life cycle processes with product- and reuse-oriented engineering and product management practices as an integrated framework for process assessment and improvement in contexts where systems are developed and evolved as products.     

Testing component-based software: a cautionary tale

Components designed for reuse are expected to lower costs and shorten the development life cycle, but this may not prove so simple. The author emphasizes the need to closely examine a problematic aspect of component reuse: the necessity and potential expense of validating components in their new environments     

On model typing

Where object-oriented languages deal with objects as described by classes, model-driven development uses models, as graphs of interconnected objects, described by metamodels. A number of new languages have been and continue to be developed for this model-based paradigm, both for model transformation and for general programming using models. Many of these use single-object approaches to typing, derived from solutions found in object-oriented systems, while others use metamodels as model types, but without a clear notion of polymorphism. Both of these approaches lead to brittle and overly restrictive reuse characteristics. In this paper we propose a simple extension to object-oriented typing to better cater for a model-oriented context, including a simple strategy for typing models as a collection of interconnected objects. We suggest extensions to existing type system formalisms to support these concepts and their manipulation. Using a simple example we show how this extended approach permits more flexible reuse, while preserving type safety.     

An experimental approach to the performance penalty of the use of classes in Fortran 95

Fortran 95 is used often for “number crunching”: scientific and engineering applications where performance is important and which operate with large datasets. The language allows the implementation of certain elements of object oriented design, which facilitate code expansion, reuse and maintenance. In this paper we discuss two series of tests to measure how different object oriented design elements of Fortran 95 affect overall performance. The first series of tests consists of several implementations for multiplying two matrices. These tests are focused exclusively on computation time, not considering other parts of the object life cycle such as construction and destruction. The second series consists of computing a finite element matrix for a diffusion term. A more complex environment with different classes is studied. Here, we consider not only the time spent doing useful computations but the integral object life cycle. Results show that object oriented design comes at a cost in all cases. However, given the right compiler, using the right compiler optimization techniques and keeping the amount of objects and method calls low, Fortran 95 designs can benefit from object oriented design techniques with a less than 10% running time increase.     

Implementation of the conformation of MSC and SDL diagrams in the REAL technology

Various methods of relating MSC and SDL diagrams are considered, including methods that allow one to automate manual conversion from scenarios of the behavior of the entire system (HMSC/MSC) to behavior models of separate objects (SDL), methods for supporting their conformity during the entire life cycle (concerted modification), and extensions of the MSC diagrams for real situations. The existing algorithms are reviewed, their advantages and disadvantages are considered, and our own approaches eliminating the disadvantages are proposed. The proposed algorithms are integrated into one complex.     

Understanding the trust of software‐intensive distributed systems

An early understanding of the trust concerns while composing a distributed system from independently developed software services saves time and effort. It also allows the developer of such distributed systems to reason about the trust‐related properties of these systems. Although there are prevalent approaches for evaluating the trust of such systems, it is not clear which approach, if any, is the most comprehensive and best suited for a given situation. Moreover, there is no agreement about a unified approach, for quantifying trust, which can be applied to the entire software life‐cycle of distributed systems. This article, first, motivates the need for such a quantification of trust via a case study from the domain of indoor tracking. It then provides a comprehensive survey of current approaches that define trust, in general domains, and then focuses on the relevant approaches from the domain of software‐oriented distributed systems. These prevalent efforts are categorized into groups using existing clustering tools and then are further analyzed for their comprehensiveness. The analysis depicts: (1) many trust‐related efforts and associated models have their own constrained views of trust; (2) different trust models focus on different aspects of trust and life‐cycle details; and (3) it is difficult to interoperate across different trust models. Hence, the paper identifies a set of principles that can assist in quantifying and evaluating the trust throughout the software life‐cycle of distributed systems. These principles, then, are applied to the aforementioned case study to provide an outline of how trustworthy distributed systems can be composed from independent software services. Copyright © 2015 John Wiley & Sons, Ltd.     

ASP.NET页面间传值综述

对ASP.NET中各种页面间传值方法进行综述,阐述实现这些方法所必需的对象的概念、作用和特点,讨论这些方法的优缺点,通过实例代码给出这些方法的基本应用,并从生命周期、应用范围、可传递的数据类型和数据量4个方面对这些方法进行比较和分析。介绍了实现这些方法时常用的2种页面重定向方法。     

基于本体的多星测控调度问题模型研究

针对多星测控调度问题中存在的模型众多、交互困难的不足,引入本体工具分析了多星测控调度问题中各种对象及对象之间的关系,给出了多星测控调度问题中概念本体的构建方法,建立了多星测控调度问题模型框架,为准确表述领域知识、实现模型及数据的重用和交互打下基础。最后利用示例描述说明了模型框架的兼容性。     

Organizational factors and reuse

Reuse is not just a technical issue. Hewlett-Packard studied why people sometimes resist reuse and which organizational models appear to encourage reuse more than others. The study found that successful reuse programs must be integrated within the culture of a company's existing organizational structure. One crucial organizational factor is the relationship between producers and consumers of reuse components and services. What are these relationships and how well do they work? To answer this question, I conducted an empirical study of 10 engineering sites at Hewlett-Packard engaged in systematic reuse. From this reuse experience, I identified four models of producer-consumer relationships; evaluated the models in terms of their organizational structures, advantages, and disadvantages; and identified goals for management to enable a successful implementation. The four models are: lone producer, nested producer, pool producer and team producer. Two or more models may occur within a given reuse program. Recommendations to management are based on both current successful practices and interviewees' suggestions. I also include some tentative guidelines on which environments are best suited to each model     

Software Component Models

Component-based development (CBD) is an important emerging topic in software engineering, promising long-sought-after benefits like increased reuse, reduced time to market, and, hence, reduced software production cost. The cornerstone of a CBD technology is its underlying software component model, which defines components and their composition mechanisms. Current models use objects or architectural units as components. These are not ideal for component reuse or systematic composition. In this paper, we survey and analyze current component models and classify them into a taxonomy based on commonly accepted desiderata for CBD. For each category in the taxonomy, we describe its key characteristics and evaluate them with respect to these desiderata.     

Performance and energy consumption estimation for commercial off-the-shelf component system design

Nowadays, component-based embedded real- time systems have been used to improve the system development as well as to keep cost down through the reuse of embedded software applications. Besides, the use of semi-formal models has been widely adopted in the embedded real-time system component and system life cycle due to their friendly and intuitive notations. However, the ever more complex systems of today require modeling methods that allow early detection of potential problems in the initial phases of development. This paper presents the mapping process of UML state machine diagram into a time Petri net with energy constraints so as to estimate execution time and energy consumption in early phases of the embedded real-time component development life cycle. The estimates obtained from the model show that the proposed approach is indeed a good approximation to the respective measures obtained from the real hardware platform.     

Viewing maintenance as reuse-oriented software development

The author presents a high-level organizational paradigm for development and maintenance in which an organization can learn from development and maintenance tasks and then apply that paradigm to several maintenance process models. Associated with the paradigm is a mechanism for setting measurable goals, making it possible to evaluate the process and the product and learn from experience. He discusses three maintenance models: the quick-fix, the iterative-enhancement, and the full-reuse model. He establishes a framework for classifying reusable objects and selecting a model. He offers a scheme that categorizes three aspects of reuse: the reusable object, the reusable object's context, and the process of transforming that object. The author then discusses what he terms reuse enablers: an improvement paradigm that helps organizations evaluate, learn, and enhance their software processes and products; a reuse-oriented evolution environment that encourages and supports reuse; and automated support for the paradigm and environment as well as for measurement and evaluation     

A framework for reuse of user experience in Web browsing

This paper examines aspects affecting user behaviours in Web browsing with a discussion of existing models for both the computer and human aspects of Web browsing. Problems in Web information retrieval are analysed and studies related to the reuse of user experience in Web browsing are reviewed. An object-oriented model for user behaviours in Web browsing is proposed in which both the information from the Web and the information retained by users are modelled as objects. Thus, user actions on the Web are described as a graph of objects or transformations from one object to another. A framework for reuse of user experience is provided. The possible methods of reusing Web browsing experience are described for the scenario of reusing by oneself (history mechanism, prediction) or reusing by others (collaborative filtering, instructions).     

A framework for reuse of user experience in Web browsing

This paper examines aspects affecting user behaviours in Web browsing with a discussion of existing models for both the computer and human aspects of Web browsing. Problems in Web information retrieval are analysed and studies related to the reuse of user experience in Web browsing are reviewed. An object-oriented model for user behaviours in Web browsing is proposed in which both the information from the Web and the information retained by users are modelled as objects. Thus, user actions on the Web are described as a graph of objects or transformations from one object to another. A framework for reuse of user experience is provided. The possible methods of reusing Web browsing experience are described for the scenario of reusing by oneself (history mechanism, prediction) or reusing by others (collaborative filtering, instructions).     

PProto: An environment for prototyping parallel programs

This paper describes Parallel Proto (PProto), an integrated environment for constructing prototypes of parallel programs. Using functional and performance modeling of dataflow specifications, PProto assists in analysis of high-level software and hardware architectural tradeoffs. Facilities provided by PProto include a visual language and an editor for describing hierarchical dataflow graphs, a resource modeling tool for creating parallel architectures, mechanisms for mapping software components to hardware components, an interactive simulator for prototype interpretation, and a reuse capability. The simulator contains components for instrumenting, animating, debugging, and displaying results of functional and performance models. The Pproto environment is built on top of a substrate for managing user interfaces and database objects to provide consistent views of design objects across system tools.