Architectural concepts and Design Patterns for behavior modeling and integration

The design of the control software for complex systems is a difficult task. It requires the modeling, the simulation, the integration and the adaptation of a multitude of interconnected entities and behaviors. To tackle this complexity, the approach proposed consists in combining architectural concepts, Design Patterns and object-oriented modeling with unified modeling language (UML). In this context, the present paper describes a modeling framework to take greater advantage of these concepts and to design flexible, intelligible control software. It proposes to objectify the behaviors, which leads to a two-level architecture based on three concepts: resources software images of the controlled system-behaviors applied to these resources, and meta-behaviors, i.e. means for behavior integration and adaptation. Two Design Patterns are proposed to describe how to specify behaviors and define the means to combine and adapt them. The first pattern, Polymorphic Behavior, provides the means to define new behaviors for a system and to plug them dynamically. The second one, Structured Behavior, provides the means to use finite state machines for behavior switching. The originality of the framework is that it defines concepts, a UML-based notation and heuristics which specifies how to apply these concepts. To illustrate the elements mentioned, this paper uses the control software of a walking robot as a running example.     

Design patterns for open tool integration

Design tool integration is a highly relevant area of software engineering that can greatly improve the efficiency of development processes. Design patterns have been widely recognized as important contributors to the success of software systems. This paper describes and compares two large-grain, architectural design patterns that solve specific design tool integration problems. Both patterns have been implemented and used in real-life engineering processes.     

Reconciling usability and interactive system architecture using patterns

Traditional interactive system architectures such as MVC [Goldberg, A., 1984. Smaltalk-80: The Interactive Programming Environment, Addison-Wesley Publ.] and PAC [Coutaz, J., 1987. PAC, an implementation model for dialog design. In: Interact’87, Sttutgart, September 1987, pp. 431-436; Coutaz, J., 1990. Architecture models for interactive software: faillures and trends. In: Cockton, G. (Ed.), Engineering for Human-Computer Interaction, Elsevier Science Publ., pp. 137-153.] decompose the system into subsystems that are relatively independent, thereby allowing the design work to be partitioned between the user interfaces and underlying functionalities. Such architectures extend the independence assumption to usability, approaching the design of the user interface as a subsystem that can designed and tested independently from the underlying functionality. This Cartesian dichotomy can be fallacious, as functionalities buried in the application’s logic can sometimes affect the usability of the system. Our investigations model the relationships between internal software attributes and externally visible usability factors. We propose a pattern-based approach for dealing with these relationships. We conclude by discussing how these patterns can lead to a methodological framework for improving interactive system architectures, and how these patterns can support the integration of usability in the software design process.     

Software architecture review by association

During the process of software design, software architects have their reasons to choose certain software components to address particular software requirements and constraints. However, existing software architecture review techniques often rely on the design reviewers’ knowledge and experience, and perhaps using some checklists, to identify design gaps and issues, without questioning the reasoning behind the decisions made by the architects. In this paper, we approach design reviews from a design reasoning perspective. We propose to use an association-based review procedure to identify design issues by first associating all the relevant design concerns, problems and solutions systematically; and then verifying if the causal relationships between these design elements are valid. Using this procedure, we discovered new design issues in all three industrial cases, despite their internal architecture reviews and one of the three systems being operational. With the newly found design issues, we derive eight general design reasoning failure scenarios.     

面向服务的企业应用集成架构研究

对传统的企业应用集成方法进行分析,提出一种基于SOA模型的企业应用集成框架,并讨论了相关的支撑技术;给出了Web Services集成实现模型—传输层、消息层、描述层、保证层和组合层。面向服务的实现企业应用集成框架的方式,能较好地解决企业原有应用系统集成的问题,从而克服了EAI传统解决方案中的缺点,建立了一套独立于语言并且跨平台的系统集成方案,并给出了一个面向服务的企业应用集成系统实例。     

Enriching software architecture documentation

The effective documentation of Architectural Knowledge (AK) is one of the key factors in leveraging the paradigm shift toward sharing and reusing AK. However, current documentation approaches have severe shortcomings in capturing the knowledge of large and complex systems and subsequently facilitating its usage. In this paper, we propose to tackle this problem through the enrichment of traditional architectural documentation with formal AK. We have developed an approach consisting of a method and an accompanying tool suite to support this enrichment. We evaluate our approach through a quasi-controlled experiment with the architecture of a real, large, and complex system. We provide empirical evidence that our approach helps to partially solve the problem and indicate further directions in managing documented AK.     

Controlling software architecture erosion: A survey

Software architectures capture the most significant properties and design constraints of software systems. Thus, modifications to a system that violate its architectural principles can degrade system performance and shorten its useful lifetime. As the potential frequency and scale of software adaptations increase to meet rapidly changing requirements and business conditions, controlling such architecture erosion becomes an important concern for software architects and developers. This paper presents a survey of techniques and technologies that have been proposed over the years either to prevent architecture erosion or to detect and restore architectures that have been eroded. These approaches, which include tools, techniques and processes, are primarily classified into three generic categories that attempt to minimise, prevent and repair architecture erosion. Within these broad categories, each approach is further broken down reflecting the high-level strategies adopted to tackle erosion. These are: process-oriented architecture conformance, architecture evolution management, architecture design enforcement, architecture to implementation linkage, self-adaptation and architecture restoration techniques consisting of recovery, discovery and reconciliation. Some of these strategies contain sub-categories under which survey results are presented.We discuss the merits and weaknesses of each strategy and argue that no single strategy can address the problem of erosion. Further, we explore the possibility of combining strategies and present a case for further work in developing a holistic framework for controlling architecture erosion.     

Bridging the gap between software architecture rationale formalisms and actual architecture documents: An ontology-driven approach

Documenting software architecture rationale is essential to reuse and evaluate architectures, and several modeling and documentation guidelines have been proposed in the literature. However, in practice creating and updating these documents rarely is a primary activity in most software projects, and rationale remains hidden in casual and semi-structured records, such as e-mails, meeting notes, wikis, and specialized documents. This paper describes the TREx (Toeska Rationale Extraction) approach to recover, represent and explore rationale information from text documents, combining: (1) pattern-based information extraction to recover rationale; (2) ontology-based representation of rationale and architectural concepts; and (3) facet-based interactive exploration of rationale. Initial results from TREx’s application suggest that some kinds of architecture rationale can be semi-automatically extracted from a project’s unstructured text documents, namely decisions, alternatives and requirements. The approach and some tools are illustrated with a case study of rationale recovery for a financial securities settlement system.     

面向服务架构在动态企业应用集成中的应用

现代企业间的竞争日趋激烈,为迅速实现业务过程重组并敏捷地响应市场变化,企业产生了进行动态企业应用集成（EAI）的需求。粗粒度的松耦合的面向服务架构（SOA）是一个支持动态EAI的具有较好健壮性的架构。通过对SOA的分析,提出了一个通用的SOA基础模型,分析了基于SOA的动态EAI技术和实现方式。最后结合医学资源网项目,开发了一个基于SOA的动态EAI平台.     

An agent-based service-oriented integration architecture for collaborative intelligent manufacturing

The rapidly changing needs and opportunities of today's global market require unprecedented levels of interoperability to integrate diverse information systems to share knowledge and collaborate among organizations. The combination of Web services and software agents provides a promising computing paradigm for efficient service selection and integration of inter-organizational business processes. This paper proposes an agent-based service-oriented integration architecture to leverage manufacturing scheduling services on a network of virtual enterprises. A unique property of this approach is that the scheduling process of an order is orchestrated on the Internet through the negotiation among agent-based Web services. A software prototype system has been implemented for inter-enterprise manufacturing resource sharing. It demonstrates how the proposed service-oriented integration architecture can be used to establish a collaborative environment that provides dynamic resource scheduling services.     

Visualization and comparison of architecture rationale with semantic web technologies

Deciding how to operationalize non-functional requirements (NFR) is a complex task, and several formalisms have been proposed to represent design decisions and their rationale. Unfortunately, these models can become complex (even unreadable) for designs with many alternatives and/or a well-documented rationale, which makes very hard to review and compare rationale. This paper introduces a Semantic Web-based technique to visualize and compare architecture rationale, combining Softgoal Interdependency Graphs (SIGs) with ontologies reified as named graphs. Reuse of rationale is thus facilitated by allowing architects to understand rationale of previous decisions and/or projects, though automated reuse remains unfeasible until extensive automated capture rationale happens. The approach is illustrated with a case study of Contexta, a museum integration project, using Toeska/Review, a Semantic Web-based tool.     

Software architecture and mobility: A roadmap

Modern software-intensive systems are characterized not only by the movement of data, as has been the case in traditional distributed systems, but also by the movement of users, devices, and code. Developing effective, efficient, and dependable systems in the mobile setting is challenging. Existing architectural principles need to be adapted and novel architectural paradigms devised. In this paper, we give an overview of the intersection of the areas of software architecture and mobility. We consider mobility from two related perspectives: (1) mobile software, which represents the computing functionality designed to migrate across hardware devices at runtime and execute on mobile hardware platforms, and (2) mobile systems, which are computing applications that include mobile software and hardware elements. We study the advances in both these areas, highlight representative existing solutions, and identify several remaining research challenges.     

基于SOA的轻量级企业整合架构设计与应用

为解决企业信息异构和数据整合问题,结合SOA和ESB技术,提出了一种轻量级SOA-ESB企业整合架构。对ESB总线层的适配转换、路由以及安全问题进行了研究,通过协议分析映射、XSLT转换、内容寻址以及加密签名等方法,实现了不同类型规范的信息在系统总线中的高效交互和共享。实验结果表明,基于SOA-ESB企业整合架构的系统平台可有效的集成各异构系统。     

设计模式在GIS软件开发中的应用研究

详细论述了组合(Composite)、桥接(Bridge)、观察者(Observer)、命令(Command)、外观(Facade)、装饰(Decora-tor)六种设计模式在GIS软件开发中的应用。旨在促使GIS开发中注重设计模式,努力发现、归纳并应用设计模式,实现软件设计的重用,提高GIS软件的质量和开发效率。     

Complex service design: A virtual enterprise architecture for logistics service

This paper presents an interdisciplinary systems approach to service modeling, design and deployment. The study is based on a longitudinal case study of the development process of a complex logistic service system based on an advanced logistics model. The case examines the development of a Virtual Enterprise Architecture (VEA) for an automatic high-speed transport and sorting system applied in airports for baggage handling. The study traces the evolution of the system from the early conceptual phases to a successful commercial service deployed at Changi, Singapore Airport. The study is conducted using a retrospective analysis of the case using a design science research approach. The paper evaluates and discusses the issues of creating and designing a new complex logistics service, distinct from the physical product, based on an advanced discrete event-based simulation model. The paper concludes by presenting a generalized and validated conceptual framework for a VEA based on an advanced simulation model. The paper thus contributes to the field of service systems and service management by identifying a novel approach to effective design of a new service.     

Design patterns for monitoring and evaluating CSCL processes

Both quantitative and qualitative methods are being increasingly used to investigate the learning dynamics that take place within CSCL environments. Since such practices are a crucial aspect of the CSCL field, Design Patterns (DPs) can be used for capitalizing on experience and sharing know-how among practitioners. This paper describes three DP instances that have been developed and fine tuned by a community of practice consisting of researchers, instructional designers and tutors with the aim of supporting monitoring and evaluation of CSCL interactions. The DP solutions are based on a set of indicators, some of quantitative and some of qualitative nature, as well as on the methods to gauge these indicators, starting from data tracked by the e-learning system. The process of development of these DPs is described and examples of use are reported and discussed in order to advance the instructional design field and inform the development of CSCL systems. The proposed DPs belong to a Language, aimed at describing tracking problems in different types of e-learning systems and at capturing in their solutions the know-how developed by communities of experts in the different fields.     

设计模式在标图系统中的综合应用

设计模式是优秀软件设计经验的总结,采用基于设计模式的方法进行系统设计将提高软件的可重用性。按照设计模式中“高内聚、低耦合”的原则,设计出一种标图系统的整体结构,并以Prototype, Template Method, Observer, Command, Composite和Singleton六种具体模式为例,详细阐述了它们在系统功能实现过程中的应用。标图系统的开发全过程充分体现了设计模式在提高软件可重用性和开发效率等方面的重要作用。     

Systemic classification of concern-based design methods in the context of enterprise architecture

Enterprise Architecture (EA) is a relatively new domain that is rapidly developing. “The primary reason for developing EA is to support business by providing the fundamental technology and process structure for an IT strategy” [TOGAF]. EA models have to model enterprises facets that span from marketing to IT. As a result, EA models tend to become large. Large EA models create a problem for model management. Concern-based design methods (CBDMs) aim to solve this problem by considering EA models as a composition of smaller, manageable parts—concerns. There are dozens of different CBDMs that can be used in the context of EA: from very generic methods to specific methods for business modeling or IT implementations. This variety of methods can cause two problems for those who develop and use innovative CBDMs in the field of Enterprise Architecture (EA). The first problem is to choose specific CBDMs that can be used in a given EA methodology: this is a problem for researchers who develop their own EA methodology. The second problem is to find similar methods (with the same problem domain or with similar frameworks) in order to make a comparative analysis with these methods: this is a problem of researchers who develop their own CBDMs related to a specific problem domain in EA (such as business process modeling or aspect oriented programming). We aim to address both of these problems by means of a definition of generic Requirements for CBDMs based on the system inquiry. We use these requirements to classify twenty CBDMs in the context of EA. We conclude with a short discussion about trends that we have observed in the field of concern-based design and modeling.