一种面向图的分布Web应用架构技术

提出一种面向图的软件体系结构描述和实现技术(称为WebGOP)来支持分布Web应用系统的架构，开发者通过定义图的拓扑结构来描述体系结构，并可以根据需要定制图的类型以更好地表达特定的体系结构风格。同时，这个图实现为一个分布共享对象，显式地存在于应用系统之中，为各个构件的执行提供了一个面向图的上下文，也为体系结构的实现和动态演化提供了依托．该技术直观性强，有助于缩小体系结构描述与实现之间的距离，特别是可为系统动态重配置提供良好的支持．该文还利用edNCE图文法对WebGOP进行了形式化处理，设计实现了一个WebGOP原型系统，并对这个原型系统的关键性能指标进行了测试以表明该技术的可行性。     

Visual programming support for graph‐oriented parallel/distributed processing

GOP is a graph‐oriented programming model which aims at providing high‐level abstractions for configuring and programming cooperative parallel processes. With GOP, the programmer can configure the logical structure of a parallel/distributed program by constructing a logical graph to represent the communication and synchronization between the local programs in a distributed processing environment. This paper describes a visual programming environment, called VisualGOP, for the design, coding, and execution of GOP programs. VisualGOP applies visual techniques to provide the programmer with automated and intelligent assistance throughout the program design and construction process. It provides a graphical interface with support for interactive graph drawing and editing, visual programming functions and automation facilities for program mapping and execution. VisualGOP is a generic programming environment independent of programming languages and platforms. GOP programs constructed under VisualGOP can run in heterogeneous parallel/distributed systems. Copyright © 2005 John Wiley & Sons, Ltd.     

A middleware‐transparent approach to developing distributed applications

An innovative middleware‐transparent approach to developing distributed applications is presented. The approach uses an aspect‐oriented software development technique to separate an application's middleware‐independent functionality from its middleware‐specific functionality. Application elements that are specific to the middleware are localized in aspects that can be seamlessly integrated into middleware‐independent application designs. The middleware‐transparent approach is used to decouple business functionality from middleware‐specific functionality. The decoupling allows developers to change middleware application elements without significantly modifying business functionality. Middleware technologies such as Java Remote Method Invocation (RMI), Jini, Simple Object Access Protocol (SOAP) remote procedure call (RPC) and .Net are used as examples to illustrate the approach. Copyright © 2005 John Wiley & Sons, Ltd.     

Composing and scheduling service‐oriented applications in time‐triggered distributed real‐time Java environments

During the last decade, the number of distributed application domains with temporal requirements has significantly augmented, arising the necessity of exploring new concepts and paradigms that allow, on the one hand, the development of dynamic and flexible distributed applications and, on the other hand, the reusability of code. Service‐oriented paradigms have been successfully applied to distributed environments, increasing their flexibility and allowing the reusability of their components. Besides, distributed real‐time Java technologies have shown to be a good candidate to deploy real‐time distributed applications. This paper presents a model for service‐oriented applications on a time‐triggered distributed real‐time Java environment, focusing on the definition of the temporal model of an application and its schedulability, applying and evaluating this model in real‐time service‐oriented composition algorithms. Copyright © 2012 John Wiley & Sons, Ltd.     

Evaluating the recovery‐oriented approach through the systematic development of real complex applications

Recovery‐oriented software is built with the perspective that hardware or software failures and operation mistakes are facts to be coped with, as they are problems that cannot be fully solved while developing real complex applications. Consequently, any software will always have a non‐zero chance of failure. Some of these failures may be caused by defects that may be removed or encapsulated. From the point of view of removing or encapsulating defects, a failure is considered to be trivial, when (i) the required effort to identify and eliminate or encapsulate the causing defect is small, (ii) the risk of making mistakes in these steps is also small and (iii) the consequences of the failure are tolerable. It is highly important to design systems in such a way that most (ideally all) of the failures are trivial. Such systems are called ‘debuggable systems’. In this study, we present the results of systematic applying techniques that focus on creating debuggable software for real embedded applications. Copyright © 2008 John Wiley & Sons, Ltd.     

A specification language and service‐oriented architecture to support distributed data management

In some research analysis organizations, effort is duplicated when disseminating raw information to multiple research groups. Although the various groups work on different problems, many times, the initial raw information used is the same. A solution to this problem is creating a centralized process for storing and disseminating common information using database technologies. In this paper, the requirements that must be met to create this distributed database management architecture are described. To support these requirements, a specification language, Specialized Format Markup Language (SFML), and supporting service‐oriented architecture, Specialized Format Generation (SFG), are introduced. These implementations and technologies support the translation of data from relational database formats into user‐specified legacy formats. In addition, this implementation supports the presentation of the resulting data across a Web‐based, distributed medium. SFML and SFG incorporate current technologies such as the eXtensible Markup Language (XML), Java Servlets, the eXtensible Stylesheet Language (XSL), and other relational database approaches. Copyright © 2004 John Wiley & Sons, Ltd.     

Object‐oriented design of the subsumption architecture

The subsumption architecture is a layered mediator invented by Rodney Brooks for behaviour‐based control of robots. The layers are minimally dependent and use minimal communication. We develop an object‐oriented software design for the subsumption architecture, and demonstrate that each layer can be used as a slot for a set of plug‐and‐play components that implement different microstrategies for achieving a particular goal. Guidelines for the development of specific layers and components of a subsumption architecture are also presented. Copyright © 2001 John Wiley & Sons, Ltd.     

Reliable self‐deployment of distributed cloud applications

Cloud applications consist of a set of interconnected software elements distributed over several virtual machines, themselves hosted on remote physical servers. Most existing solutions for deploying such applications require human intervention to configure parts of the system, do not conform to functional dependencies among elements that must be respected when starting them, and do not handle virtual machine failures that can occur when deploying an application. This paper presents a self‐deployment protocol that was designed to automatically configure a set of software elements to be deployed on different virtual machines. This protocol works in a decentralized way, that is, there is no need for a centralized server. It also starts the software elements in a certain order, respecting important architectural invariants. This protocol supports virtual machine and network failures and always succeeds in deploying an application when faced with a finite number of failures. Designing such highly parallel management protocols is difficult; therefore, formal modeling techniques and verification tools were used for validation purposes. The protocol was implemented in Java and was used to deploy industrial applications. Copyright © 2016 John Wiley & Sons, Ltd.     

The effect of a graph‐oriented computer‐assisted project‐based learning environment on argumentation skills

The purpose of this quasi‐experimental study was to explore how seventh graders in a suburban school in the United States developed argumentation skills and science knowledge in a project‐based learning environment that incorporated a graph‐oriented, computer‐assisted application. A total of 54 students (three classes) comprised this treatment condition and were engaged in a project‐based learning environment that incorporated a graph‐oriented, computer‐assisted application, whereas a total of 57 students (three classes) comprised the control condition and were engaged in a project‐based learning environment without this graph‐oriented, computer‐assisted application. Verbal collaborative argumentation was recorded and the students' post essays were collected. A random effects analysis of variance (ANOVA) was conducted and a significant difference in science knowledge about alternative energies between conditions was observed. A multivariate analysis of variance (MANOVA) was conducted and there was a significant difference in counterargument and rebuttal skills between conditions. A qualitative analysis was conducted to examine how the graph‐oriented, computer‐assisted application supported students' development of argumentation skills and affected the quality of collaborative argumentation. The difference in argumentation structure and quality of argumentation between conditions might explain a difference in science knowledge as well counterargument and rebuttal skills (argumentation) between both conditions. This study concluded that a project‐based learning environment incorporating a graph‐oriented, computer‐assisted application was effective in improving students' science knowledge and developing their scientific argumentation skills.     

Feature‐based approach to object‐oriented engineering of applications for reuse

Object‐oriented technology is gaining popularity among software engineers with the goal of building reusable and adaptable software. Unfortunately, however, most methods introduced so far are not domain‐oriented and do not address the issue of reuse directly. For these methods, software reuse is not the primary goal; it is only a by‐product. The feature‐oriented reuse method, FORM, is extended in this paper for improving the object‐oriented engineering of applications for reuse. FORM concentrates on analyzing and modeling commonalities and differences in the applications of a given domain in terms of capability, operating environment, domain technology, and implementation technique features. These features are used to systematically derive objects that are tied to the features, and to develop reusable and adaptable domain architectures. We found that FORM facilitates analysis of variability (and commonality) of software before engineering and implementation start, and with this understanding, adaptability and reusability can be built into software. Feature modeling has been found to be an effective method for identifying and modeling reusable objects. Copyright © 2000 John Wiley & Sons, Ltd.     

Model‐driven design of collaborative Web applications

This paper introduces a model‐driven approach to the design of collaborative Web‐based applications, i.e. applications in which several users play different roles, in a collaborative way, to pursue a specific goal. The paper illustrates a conference management application (CMA), whose main requirements include: (i) the management of users profiles and access rights based on the role played by users during the conference life cycle; (ii) the delivery of information and services to individual users; (iii) the management of the sequence of activities that lead to the achievement of a common goal. The presented approach is based on WebML, a conceptual modelling language for the Web. The paper also highlights some general properties—as understood by the practical experience of CMA development—that a Web modelling language should feature in order to fully support the development of collaborative applications. Copyright © 2003 John Wiley & Sons, Ltd.     

Aspect‐oriented component assembly—a case study in parallel software design

In this paper we deal with building parallel programs based on sequential application code and generic components providing specific functionality for parallelization, like load balancing or fault tolerance. We describe an architectural approach employing aspect‐oriented programming to assemble arbitrary object‐oriented components. Several non‐trivial crosscutting concerns arising from parallelization are addressed in the light of different applications, which are representative of the most common types of parallelism. In particular, we demonstrate how aspect‐oriented techniques allow us to leave all existing code untouched. We evaluate and compare our approach with its counterparts in conventional object‐oriented programming. Copyright © 2008 John Wiley & Sons, Ltd.     

Leveraging legacy codes to distributed problem‐solving environments: a Web services approach

This paper presents WSOWG, a Web‐services‐oriented wrapper generator for automatically wrapping non‐networked legacy codes as Web services for reuse in distributed problem‐solving environments. Using WSOWG, a finite element based computational fluid dynamics (CFD) legacy code has been wrapped as a Web service. A problem‐solving environment for simulating incompressible Navier–Stokes flows has also been implemented. A user makes use of the CFD service through a Web page without knowing the exact implementation of the service. In this way, a user's computing environment can be extended to a heterogeneous distributed computing environment. Performance evaluation shows that the overhead to invoke the CFD Web service generated by WSOWG using Simple Object Access Protocol (SOAP) and CORBA Internet Inter‐ORB Protocol (IIOP) is reasonable compared with that of invoking another CFD Web service manually wrapped from the CFD legacy code using SOAP only. Copyright © 2004 John Wiley & Sons, Ltd.     

Some technical and non‐technical issues in implementing a knowledge server

Increasingly, knowledge, as well as information and data, is being transferred over the World Wide Web. There is great potential in linking traditional knowledge‐based systems (KBS) technology with the Internet because each technology can overcome limitations in the other. As a result, it might enable expert knowledge that has hitherto been confined to those who possess the correct computing platforms to be made available to small enterprises and people in developing countries. Five types of KBS–Internet integration are outlined (Intelligent Agents, Active Web Pages, Local KBS Accessing Web‐distributed Information, Web‐distributed Knowledge Bases, and Knowledge Servers). This paper discusses knowledge servers in detail. It examines the issues and problems that must be addressed if existing KBS inference software is to be integrated with the World Wide Web, and discusses, in depth, solutions as implemented in the Istar knowledge server. The paper shows how technical design and implementation decisions can be influenced, not only by the technical characteristics of the Internet, but also by a range of other, ‘softer’ issues. In particular, it shows how real life styles of WWW browsing, and a desire to make knowledge available to developing countries, influences both overall architecture and detailed implementation decisions. Early experience of actual usage shows Istar to be a highly efficient knowledge server. Directions for future research are discussed. Copyright © 2000 John Wiley & Sons, Ltd.     

Toward a modular and efficient distribution for Web service handlers

Over the last few decades, distributed systems have architecturally evolved. One recent evolutionary step is SOA. The SOA model is perfectly engendered in Web services, which provide software platforms for building applications as services. Web services utilize supportive capabilities such as security, reliability, and monitoring. These capabilities are typically provisioned as handlers, which incrementally add new features. Even though handlers are very important, the method of utilization is crucial for obtaining potential benefits. Every attempt to support a service with an additional handler increases the chance of an overwhelmingly crowded handler chain. Moreover, a handler may become a bottleneck because of its comparably higher processing time. In this paper, we present the Distributed Handler Architecture to provide an efficient, scalable, and modular architecture. The performance and scalability benchmarks show that the distributed and parallel handler executions are very promising for suitable handler configurations. The paper is concluded with remarks on the fundamentals of a promising computing environment for Web service handlers. Copyright © 2012 John Wiley & Sons, Ltd.     

Coloring,a versatile technique for implementing object‐oriented languages

Late binding and subtyping create run‐time overhead for object‐oriented languages. Dynamic typing and multiple inheritance create even more overhead. Static typing and single inheritance lead to two major invariants, of reference and position, that make the implementation as efficient as possible. Coloring is a technique that preserves these invariants for dynamic typing or multiple inheritance at minimal spatial cost. Coloring has been independently proposed for method invocation under the name of selector coloring, for subtype tests under the name of pack encoding, and for attribute access and object layout. This paper reviews a number of uses of coloring for optimizing object‐oriented programming, generalizes them, and specifies several variations, such as bidirectional and n‐directional coloring. Coloring is NP‐hard, hence compilers that use it depend on heuristics. The paper describes two families of heuristics and presents some experimental results which indicate that coloring is both efficient and tractable and that bidirectional coloring gives the best results. Copyright © 2010 John Wiley & Sons, Ltd.     

Implementation of a TMO‐structured real‐time airplane‐landing simulator on a distributed computing environment

In real‐time simulation, the simulated system should display the same (or very close) timing behavior as the target system. The simulation accuracy is increased as the simulation time unit is decreased. Although there are several models for such systems, the TMO model is particularly appropriate due to its natural support for real‐time distributed object‐oriented programming. This paper discusses the results of the implementation of a real‐time airplane‐landing simulator on a distributed computing environment using the TMO model. Copyright © 2004 John Wiley & Sons, Ltd.     

A cross‐cultural study of the effect of a graph‐oriented computer‐assisted project‐based learning environment on middle school students' science knowledge and argumentation skills

The purpose of this mixed‐methods study was to explore how seventh graders in a suburban school in the United States and sixth graders in an urban school in Taiwan developed argumentation skills and science knowledge in a project‐based learning environment that incorporated a graph‐oriented, computer‐assisted application (GOCAA). A total of 42 students comprised the treatment condition and were engaged in a project‐based learning environment that incorporated a GOCAA. Of these 42 students, 21 were located in the United States and 21 were located in Taiwan. A total of 26 students comprised the control condition and were engaged in a project‐based learning environment without the GOCAA. Of these 26 students, 15 were in the United States and 11 were in Taiwan. In each country, verbal collaborative argumentation was recorded and the students' post‐essays were collected. A one‐way analysis of variance (ANOVA) was conducted for each measure of science knowledge about alternative energies. The results showed a significant treatment effect for the outcome of scientific explanation among U.S. students, while among Taiwanese students, a significant treatment effect on scientific facts was observed. A one‐way ANOVA was additionally conducted for each measure of argumentation skills and a significant treatment effect on counterarguments and rebuttals was observed among the U.S. students, while in Taiwan, a significant treatment effect on reasoning and rebuttals was observed. A qualitative analysis was conducted to examine how the GOCAA supported students' development of argumentation skills in different countries. This study found distinct argumentation patterns between the U.S. and Taiwanese intervention teams. Additionally, a distinct gender difference in the use of evidence and division of labour was noted when the Taiwanese teams were compared with the U.S. teams, which may be explained by cultural differences. This study concluded that, in both the United States and Taiwan, a project‐based learning environment incorporating a GOCAA was effective in improving students' science knowledge and developing their scientific argumentation skills.     

A task‐based and resource‐aware approach to dynamically generate optimal software architecture for intelligent service robots

Intelligent service robots provide various services to users by understanding the context and goals of a user task. In order to provide more reliable services, intelligent service robots need to consider various factors, such as their surrounding environments, users' changing needs, and constrained resources. To handle these factors, most of the intelligent service robots are controlled by a task‐based control system, which generates a task plan that represents a sequence of actions, and executes those actions by invoking the corresponding functions. However, the traditional task‐based control systems lack the consideration of resource factors even though intelligent service robots have limited resources (limited computational power, memory space, and network bandwidth). Moreover, system‐specific concerns such as the relationships among functional modules are not considered during the task generation phase. Without considering both the resource conditions and interdependencies among software modules as a whole, it will be difficult to efficiently manage the functionalities that are essential to provide core services to users. In this paper, we propose a mechanism for intelligent service robots to efficiently use their resources on‐demand by separating system‐specific information from task generation. We have defined a sub‐architecture that corresponds to each action of a task plan, and provides a way of using the limited resources by minimizing redundant software components and maintaining essential components for the current action. To support the optimization of resource consumption, we have developed a two‐phase optimization process, which is composed of the topological and temporal optimization steps. We have conducted an experiment with these mechanisms for an infotainment robot, and simulated the optimization process. Results show that our approach contributed to increase the utilization rate by 20% of the robot resources. Copyright © 2011 John Wiley & Sons, Ltd.