系统互通性的模型与测量研究

软件系统的数量日益庞大,人们渐渐开始关注如何让多种软件系统协同工作来完成特定的任务,这也正是系统互通性研究的问题。本文从研究系统互通性的必要性入手,给出了系统互通性的概念,描述了提高系统互通性的困难所在,以及目前提高系统互通性的模型方法,最后对评价系统互通性质量的相关测量问题进行了分析探讨,提出了改进意见。     

A review of interoperability assessment models

Interoperability is the ability of systems to provide services to and accept services from other systems, and to use the services exchanged so as to operate together in a more effective manner. The fact that interoperability can be improved means that the metrics for measuring interoperability can be defined. For the purpose of measuring the interoperability between systems, an interoperability assessment model is required. This paper deals with the existing interoperability assessment models. A compara- tive analysis among these models is provided to evaluate the similarities and differences in their philosophy and implementation. The analysis yields a set of recommendations for any party that is open to the idea of creating or improving an interoperability assessment model.     

The ethical and social implications of personalization technologies for e-learning

Personalization in information systems can be considered beneficial but also ethically and socially harmful. Like many other technologies, the uptake of personalization has been rapid, with inadequate consideration given to its effects. Personalization in e-learning systems also has potential for both harmful and beneficial outcomes, but less is known about its effects. The ethical and social hazards include privacy compromise, lack of control, reduced individual capability, and the commodification of education. Personalization is appearing in many systems already; thus, these hazards may already be occurring. Solutions, more research and community discussion of the issues are needed.     

Supporting high interoperability of components by adopting an agent-based approach

While integrating components into systems, we will be confronted with problems concerned with the interoperability of components due to the interaction mismatches at multiple levels, such as interaction behaviors between components and features imposed by architectural styles. In this paper, we studied the interoperability of components and explored the approach to supporting high interoperability of components involved in mismatching interactions. First, we formalized components involved in different architectural styles in the pi-calculus. Next, we studied the formal foundation of the interoperability of components for reasoning about the conditions under which two heterogeneous components are possible to interoperate and interconnect together properly. Then, we described a wrapper-based solution for integrating components into systems that impose mismatching assumptions about usage of the components. In the end, we presented an agent-based implementation for the solution, in which agents are used to wrap components and can automatically resolve multiple levels of interaction mismatches between components. We also gave a simple example to illustrate our approach.

Supporting safe metamodel evolution with edelta

Metamodels play a crucial role in any model-based application. They underpin the definition of models and tools, and the development of model management operations, including model transformations and analysis. Like any software artifacts, metamodels are subject to evolution to improve their quality or implement unforeseen requirements. Metamodels can be defined in terms of existing ones to increase the separation of concerns and foster reuse. However, the induced coupling can give additional evolution complexity, and dedicated support is needed to avoid breaking metamodels defined in terms of those being changed. This paper presents a tool-supported approach that can automatically analyze the available metamodels and alert modelers in case of change operations that can give place to invalid situations like dangling references. The approach has been implemented in the Edelta development environment and successfully applied to metamodels retrieved from a publicly available Ecore models dataset.

     

A study of the relationship between institutional policy,organisational culture and e-learning use in four South African universities

This article investigates the relationship between policy (conceptualised as goals, values and resources), organisational culture and e-learning use. Through both qualitative and quantitative research methods, we gathered data about staff and student perspectives from four diverse South African universities representing a selection of ICT in education policy types (Structured and Unstructured) and organisational cultural types of “collegium, bureaucracy, corporate and enterprise” (McNay, 1995). While our findings show a clear relationship between policy and use of ICTs for teaching and learning, organisational culture is found crucial to policy mediation and the way that e-learning use is embedded within the organisation. We conclude that although a Structured Corporate institutional type enables the attainment of a “critical mass” within e-learning, Unstructured Collegium institutions are better at fostering innovation. Unstructured Bureaucratic institutions are the least enabling of either top down or bottom up e-learning change.     

The evolution of intellectual technologies: Applying product life-cycle models to MIS implementation

This article develops the theoretical construct of an “intellectual technology” (as distinct from traditional industrial technologies) as a way to explain the difficulties organizations have in implementing new computer-based applications. Building on the notions of a product and process life-cycle, this concept is used to suggest that non-traditional approaches to the implementation of computer-based applications may be necessary. The “intellectual technology” concept implies that organizations must learn to apply new applications in their particular environment, and that this learning explains the difficulty many firms have in implementing Office Automation, CAD/CAM, Decision Support Systems, and the like.     

Exploring the interoperability of remote GPGPU virtualization using rCUDA and directive-based programming models

Directive-based programming models, such as OpenMP, OpenACC, and OmpSs, enable users to accelerate applications by using coprocessors with little effort. These devices offer significant computing power, but their use can introduce two problems: an increase in the total cost of ownership and their underutilization because not all codes match their architecture. Remote accelerator virtualization frameworks address those problems. In particular, rCUDA provides transparent access to any graphic processor unit installed in a cluster, reducing the number of accelerators and increasing their utilization ratio. Joining these two technologies, directive-based programming models and rCUDA, is thus highly appealing. In this work, we study the integration of OmpSs and OpenACC with rCUDA, describing and analyzing several applications over three different hardware configurations that include two InfiniBand interconnections and three NVIDIA accelerators. Our evaluation reveals favorable performance results, showing low overhead and similar scaling factors when using remote accelerators instead of local devices.     

电子学习系统中的知识表示与知识发现模型研究

领域本体提供了丰富的概念集,是领域知识共享的基础。讨论了电子教学系统中课程知识体系的组织与本体表示方法,构造了基于领域本体的知识发现模型,阐述了基于领域概念对相似性的本体映射过程,实现了基于单元知识的电子教学资源的灵活共享。     

Supporting information evolution on the WWW

This paper describes a simple versioning system which we have developed to support collaborative authoring on the WWW. The system provides facilities for versioning pages and allowing readers access to different versions of web pages. We discuss why such a system is needed and present the versioning model which we have developed. This model allows existing web pages to be converted to versioned entities without affecting links to these pages. Central to the model, is a set of access control facilities which allows authors to provide coauthors with access to versions of pages under development. We describe the instantiation of this model and assess our work against the requirements identified in the first part of the paper.     

Towards interoperability of i* models using iStarML

Goal-oriented and agent-oriented modelling provides an effective approach to the understanding of distributed information systems that need to operate in open, heterogeneous and evolving environments. Frameworks, firstly introduced more than ten years ago, have been extended along language variants, analysis methods and CASE tools, posing language semantics and tool interoperability issues. Among them, the i* framework is one the most widespread. We focus on i*-based modelling languages and tools and on the problem of supporting model exchange between them. In this paper, we introduce the i* interoperability problem and derive an XML interchange format, called iStarML, as a practical solution to this problem. We first discuss the main requirements for its definition, then we characterise the core concepts of i* and we detail the tags and options of the interchange format. We complete the presentation of iStarML showing some possible applications. Finally, a survey on the i* community perception about iStarML is included for assessment purposes.     

Experiments on semantic interoperability of agent reputation models using the SOARI architecture

In the last decades, we have experienced a rapid increase in the number of available online e-services. Agent-based computing has been advocated as a natural computational model to automate the interaction with those services, thus enabling the formation of multiagent systems. In these latter, agents may use trust and reputation as the main control mechanism and they usually exchange such information in order to accelerate reputation evaluation. However, due to the semantic heterogeneity of the different reputation models, agents interaction about reputation has to deal with interoperability issues. Therefore, this paper presents some experiments using SOARI, an architecture that enables the semantic interoperability among agents that have heterogeneous reputation models. Such experiments were conducted using two reputation testbeds and three agent reputation models in order to analyze the accuracy of the agents reputation evaluation in the presence of a more expressive communication apparatus, as well as the effect of the heterogeneity among reputation models on this accuracy.     

II. Supporting models and applications

Baaed on TOC (Task Operating Characteristic) and ROC (Resource Operating Characteristic) curves (Braswell 1971), P(t) and R(t), a family of feasible curves are experimentally selected with parameter specifications for a and S. Additional models are developed for activity progress and resource utilization monitoring and control. A resource allocation method is developed and a Best 1'ath (JJP) strategy is presented to reprogramme progress of assignments and rates of resource expending. Task Progress (TP) and Rosource Depletion (RD) models are developed. Examples, and figures illustrate applications.     

Integrating web service and semantic dialogue model for user models interoperability on the web

Nowadays there is a great number of Web information systems that build a model of the user and adapt their services according to the needs and preferences maintained by the user model (UM). One of the most challenging issues of this scenario is the possibility to enable different systems to cooperate in order to exchange the available information about a user. Our aim is to create rich (and scalable) communication protocols and infrastructures to enable consumers and providers of UM data to interact. Our solution for dealing with such an issue is to exploit Web standards for interoperability (i.e. Semantic Web and Web Services) for implementing simple atomic communication, and a dialogue model for implementing enhanced communication capabilities. In particular, two systems can start a semantics-enhanced Dialogue Game as a form of negotiation to clarify the meaning of the requested concepts when a shared knowledge model does not exist, and to approximate the response when the exact one is not available. We propose a distributed semantic conversation framework based on the Sesame semantic environment for the exchange of user model knowledge on the Web. Systems have to expose their user model data as a Web Service, and to exploit a public dialogue knowledge base to start the dialogue. The main advantage of the approach is to allow systems to deal with difficult situations by starting an appropriate dialogue game instead of stopping the communication as in the traditional “all-or-nothing” Web Service approach. On the basis of a preliminary evaluation, the approach has shown an improvement of the adaptation results provided by the systems we tested.     

Supporting the reconciliation of models of object behaviour

This paper presents Reconciliation+, a method which identifies overlaps between models of software systems behaviour expressed as UML object interaction diagrams (i.e., sequence and/or collaboration diagrams), checks whether the overlapping elements of these models satisfy specific consistency rules and, in cases where they violate these rules, guides software designers in handling the detected inconsistencies. The method detects overlaps between object interaction diagrams by using a probabilistic message matching algorithm that has been developed for this purpose. The guidance to software designers on when to check for inconsistencies and how to deal with them is delivered by enacting a built-in process model that specifies the consistency rules that can be checked against overlapping models and different ways of handling violations of these rules. Reconciliation+ is supported by a toolkit. It has also been evaluated in a case study. This case study has produced positive results which are discussed in the paper.     

Predicting user acceptance of collaborative technologies: An extension of the technology acceptance model for e-learning

Collaborative technologies support group work in project-based environments. In this study, we enhance the technology acceptance model to explain the factors that influence the acceptance of Google Applications for collaborative learning. The enhanced model was empirically evaluated using survey data collected from 136 students enrolled in a full-time degree program that used Google Applications to support project work. According to the research results, determinants of the technology acceptance model are the major factors influencing the adoption of the technology. In addition, the subjective norm represented by peers is found to significantly moderate the relationship between attitude and intention toward the technology. However, our results do not show a significant effect of subjective norms represented by instructors and mass media on students' intentions to use the technology. The ability to share information in the collaborative learning environment is found to influence intention and behavior toward the Google Applications platform.