User-author centered multimedia building blocks

The advances of multimedia models and tools popularized the access and production of multimedia contents: in this new scenario, there is no longer a clear distinction between authors and end-users of a production. These user-authors often work in a collaborative way. As end-users, they collectively participate in interactive environments, consuming multimedia artifacts. In their authors’ role, instead of starting from scratch, they often reuse others’ productions, which can be decomposed, fusioned and transformed to meet their goals. Since the need for sharing and adapting productions is felt by many communities, there has been a proliferation of standards and mechanisms to exchange complex digital objects, for distinct application domains. However, these initiatives have created another level of complexity, since people have to define which share/ reuse solution they want to adopt, and may even have to resort to programming tasks. They also lack effective strategies to combine these reused artifacts. This paper presents a solution to this demand, based on a user-author centered multimedia building block model—the digital content component (DCC). DCCs upgrade the notion of digital objects to digital components, as they homogenously wrap any kind of digital content (e.g., multimedia artifacts, software) inside a single component abstraction. The model is fully supported by a software infrastructure, which exploits the model’s semantic power to automate low level technical activities, thereby freeing user-authors to concentrate on creative tasks. Model and infrastructure improve recent research initiatives to standardize the means of sharing and reuse domain specific digital contents. The paper’s contributions are illustrated using examples implemented in a DCC-based authoring tool, in real life situations.     

METEOR-S WSDI: A Scalable P2P Infrastructure of Registries for Semantic Publication and Discovery of Web Services

Web services are the new paradigm for distributed computing. They have much to offer towards interoperability of applications and integration of large scale distributed systems. To make Web services accessible to users, service providers use Web service registries to publish them. Current infrastructure of registries requires replication of all Web service publications in all Universal Business Registries. Large growth in number of Web services as well as the growth in the number of registries would make this replication impractical. In addition, the current Web service discovery mechanism is inefficient, as it does not support discovery based on the capabilities of the services, leading to a lot of irrelevant matches. Semantic discovery or matching of services is a promising approach to address this challenge. In this paper, we present a scalable, high performance environment for Web service publication and discovery among multiple registries. This work uses an ontology-based approach to organize registries into domains, enabling domain based classification of all Web services. Each of these registries supports semantic publication and discovery of Web services. We believe that the semantic approach suggested in this paper will significantly improve Web service publication and discovery involving a large number of registries. This paper describes the implementation and architecture of the METEOR-S Web Service Discovery Infrastructure, which leverages peer-to-peer computing as a scalable solution.     

基于语义相似度的Web服务发现研究

Web服务的大量涌现对服务发现提出了挑战,UDDI上基于关键词和简单分类的服务发现机制已经不能很好满足需要。文中在分析现有相关研究的基础上,给出了一种基于语义相似度的Web服务发现方法。该方法充分利用服务中存在的语义信息,针对服务请求和广告服务中描述的功能进行匹配,并通过语义相似度来衡量两者匹配的程度。文中具体给出了服务间语义相似度的计算方法并通过示例说明了服务匹配的过程。     

基于UDDI的Web服务发现研究

基于UDDI的Web服务发现机制仅提供了基于语法层关键字的匹配方法,缺乏语义推理的支持.在相关研究的基础之上,提出了一个基于UDDI的Web服务注册/发现方法,使得服务提供者可以发布OWL-S语言描述的服务,并发布到UDDI注册中心.在传统UDDI注册中心之外新建一层Sem-UDDI注册中心,使用Sem-UDDI注册中心来存储服务的语义信息和服务相关的分类属性,并由服务匹配引擎计算服务属性之间的语义相似度,从而支持基于语义的推理查询,增强了UDDI的语义Web服务发现的能力.     

Taxonomy of digital community currency platforms*

ABSTRACT

Community currencies are used to pay for products or services within specific groups defined by geographical boundaries or specific common interests. Financial crises, social emergence in developing countries, and increased access to digital devices have stimulated a growing number of communities worldwide to develop digital currency projects. These projects use technologies ranging from traditional plastic cards to mobile phones and blockchain technologies. Following the design science research approach, this paper analyzes digital community currencies (DCCs) by developing a taxonomy based on platform architecture, governance, transactionality and virtuality. By investigating 22 DCC platforms around the world, 4 groups were distinguished: local, proprietary, commons and cyber. The identification of these four different groups of digital community currencies allows us to better discuss the potentials and limitations of each one of them. The presented taxonomy can be useful to researchers and practitioners both to explain and to design DCC platforms. Discussing each of the emerging categories from the proposed taxonomy helps us to provide insights into DCCs, offering a new theoretical frame for investigating the particular case of digital payment platforms.     

基于语义的Web服务发现机制研究

针对基于加语义描述,构建一种基于语义的Web服务发现机制.将Web服务请求进行语义解析,生成请求服务文档,在服务注册库中通过服务匹配算法,得到候选服务集,并借助线形评价标准对所选服务进行语义评估,为服务请求者选择最优的服务.     

Towards a semantic infrastructure for context-aware e-learning

Architectural supports, e.g., user context processing and learning content management are essential for facilitating the development and proliferation of context-aware e-learning services. In this paper, we propose a context-aware e-learning infrastructure called Semantic Learning Space. It leverages the Semantic Web technologies to support semantic knowledge representation, systematic context management, interoperable content integration, expressive knowledge query, and adaptive content recommendation. The functionality encapsulated in the infrastructure handles the common, time-consuming and low-level details in learning context processing and content management. The architectural design and enabling technologies are described in detail. Finally, the prototype implementation and preliminary experimental results are presented.     

基于方面的动态自适应WEB服务器的研究与实现

WEB服务器面临的是变化多端的运行时需求,我们可以通过离线的方法来调整方针和重配参数,以处理这些需求。但这却不适用于长时间运行的WEB服务器。许多需要自适应的方针,本质上就是横切的。面向方面编程（AOP）提供了一些机制,用来将横切的方针封装为方面。我们将静态配置WEB服务器与动态方面编织装置相结合,把一个WEB服务器改造为动态自适应的WEB服务器,它能根据需求的变化,在运行时调整自身的方针和配置参数。     

OWL-FC: an upper ontology for semantic modeling of Fuzzy Control

This work introduces an OWL-based upper ontology, called OWL-FC (Ontology Web Language for Fuzzy Control), capable to support a semantic definition of Fuzzy Control. It focuses on the fuzzy rules representation by providing domain independent ontology, supporting interoperability and favoring domain ontologies re-usability. The main contribution is that OWL-FC exploits Fuzzy Logic in OWL to model vagueness and uncertainty of the real world. Moreover, OWL-FC enables automatic discovery and execution of fuzzy controllers, by means of context aware parameter setting: appropriate controllers can be activated, depending on the parameters proactively identified in the work environment. In fact, the semantic modeling of concepts allows the characterization of constraints and restrictions for the identification of the right matches between concepts and individuals. OWL-FC ontology provides a wide, semantic-based interoperability among different domain ontologies, through the specification of fuzzy concepts, independently by the application domain. Then, OWL-FC is coherent to the Semantic Web infrastructure and avoids inconsistencies in the ontology.     

Toward an OSGi-based infrastructure for context-aware applications

Applications and services must adapt to changing contexts in dynamic environments. However, building context-aware applications is still complex and time-consuming due to inadequate infrastructure support. We propose a context-aware infrastructure for building and rapidly prototyping such applications in a smart-home environment. This OSGi-based infrastructure manages context-aware services reliably and securely and efficiently supports context acquisition, discovery, and reasoning. A formal, ontology-based context model enables semantic context representation, reasoning, and knowledge sharing. We propose an ontology-based context model that leverages Semantic Web technology and OWL (Web Ontology Language). OWL is an ontology markup language that enables context sharing and context reasoning. Based on our context model, we also propose a service-oriented context-aware middleware (SOCAM) architecture, including a set of independent services that perform context discovery, acquisition, and interpretation.     

PGSW-OS: a novel approach for resource management in a semantic web operating system based on a P2P grid architecture

A web operating system is an operating system that users can access from any hardware at any location. A peer-to-peer (P2P) grid uses P2P communication for resource management and communication between nodes in a grid and manages resources locally in each cluster, and this provides a proper architecture for a web operating system. Use of semantic technology in web operating systems is an emerging field that improves the management and discovery of resources and services. In this paper, we propose PGSW-OS (P2P grid semantic Web OS), a model based on a P2P grid architecture and semantic technology to improve resource management in a web operating system through resource discovery with the aid of semantic features. Our approach integrates distributed hash tables (DHTs) and semantic overlay networks to enable semantic-based resource management by advertising resources in the DHT based upon their annotations to enable semantic-based resource matchmaking. Our model includes ontologies and virtual organizations. Our technique decreases the computational complexity of searching in a web operating system environment. We perform a simulation study using the Gridsim simulator, and our experiments show that our model provides enhanced utilization of resources, better search expressiveness, scalability, and precision.     

基于语义的Web服务发现机制研究

针对基于关键词Web服务发现的不足,采用OWL-S作为服务描述语言,为Web服务添加语义描述,构建一种基于语义的Web服务发现机制.本文首先将Web服务请求进行语义解析,生成请求服务文档,然后在服务注册库中通过服务匹配算法,得到候选服务集,并借助线形评价标准对所选服务进行语义评估,为服务请求者选择最优的服务.     

SemWebDL: A privacy-preserving Semantic Web infrastructure for digital libraries

Recent advances in digital libraries have been closely intertwined with advances in Internet technologies. With the advent of the Web, digital libraries have been able to reach constituencies previously unanticipated. Because of the wide deployability of Web-accessible digital libraries, the potential for privacy violations has also grown tremendously. The much touted Semantic Web, with its agent, service, and ontology technologies, is slated to take the Web to another qualitative level in advances. Unfortunately, these advances may also open doors for privacy violations in ways never seen before. We propose a Semantic Web infrastructure, called SemWebDL, that enables the dynamic composition of disparate and autonomous digital libraries while preserving user privacy. In the proposed infrastructure, users will be able to pose more qualitative queries that may require the ad hoc collaboration of multiple digital libraries. In addition to the Semantic Web-based infrastructure, the quality of the response would rest on extraneous information in the form of a profile. We introduce the concept of communities to enable subject-based cooperation and search speedup. Further, digital libraries heterogeneity and autonomy are transcended by a layered Web-service-based infrastructure. Semantic Web-based digital library providers would advertise to Web services, which in turn are organized in communities accessed by users. For the purpose of privacy preservation, we devise a three-tier privacy model consisting of user privacy, Web service privacy, and digital library privacy that offers autonomy of perspectives for privacy definition and violation. We propose an approach that seamlessly interoperates with potentially conflicting privacy definitions and policies at the different levels of the Semantic Web-based infrastructure. A key aspect in the approach is the use of reputations for outsourcing Web services. A Web service reputation is associated with its behavior with regard to privacy preservation. We developed a technique that uses attribute ontologies and information flow difference to collect, evaluate, and disseminate the reputation of Web services.     

基于XQuery扩展的异构语义Web服务发现

语义Web服务发现作为分布式计算的前提和关键,备受研究者关注。多种语义Web服务描述语言的存在给异构语义Web服务的发现带来了挑战。本文提出了一种支持异构语义Web服务描述语言的发现框架i XQuery。该框架从两个方面扩展XQuery,使其支持异构语义Web服务的结构化查询与逻辑推理、模糊匹配的联合查询。一方面i XQuery利用XQuery的外部函数机制,建立了多种类型的相似度比较函数;另一方面i XQuery制定了一个统一的语义Web服务抽象描述本体,并建立了语义Web服务语言SAWSDL与OWLS与该本体之间的映射,并利用XQuery的用户自定义函数机制,建立了一系列用于抽取异构语义Web服务中信息的抽象描述操作子。最后,介绍了基于i XQuery框架的异构语义Web服务匹配器H-i Matcher。     

基于OWL-S的Web服务发现系统的研究和实现

文中针对目前基于WSDL,UDDI等技术的Web服务发现存在的不足,提出了一种使用OWL-S进行Web服务描述的新的服务发现机制。介绍了Web服务的语义描述语言OWL-S,设计并实现了一个Web服务发现系统。同时,详细介绍了存储Web服务OWL-S描述信息的数据库结构的设计,以及服务请求时进行服务匹配使用的匹配算法。     

一种基于循环匹配的Web服务发现策略

随着互联网的高速发展和广泛应用,互联网用户对服务的要求越来越高,同时开发人员对代码的重用和应用服务松耦合的要求也越来越高。Web服务则提供了一种解决上述问题的方法,而传统的Web服务匹配主要是基于关键字的,缺乏对语义的支持,因而在服务匹配方面的效率较低。采用语义概念来表达Web服务的描述性内容,并针对概念之间的二义性提出了一种循环匹配的方法来计算概念之间的相似度,并最终来确定请求服务和广告服务的相似度。最后,实验证明本文提出的策略有较好的可行性和有效性。     

基于语义的服务发现技术研究综述

语义Web服务是Web服务的语义扩展,它能够有效地提高服务发现的效率,并使得实现服务发现自动化成为可能。基于语义的服务发现是语义Web服务技术的核心,其关键技术包括标识语义的Web服务描述语言、基于语义的服务发现体系结构和基于语义的服务匹配算法。本文分别从这三个方面对目前基于语义的服务发现技术进行了详细的分析比较。文章最后对基于语义的Web服务发现技术进行了总结与展望。     

A Web Ontology Service to facilitate interoperability within a Spatial Data Infrastructure: Applicability to discovery

Ontologies are used within the context of Spatial Data Infrastructures to denote a formally represented knowledge that is used to improve data sharing and information retrieval. Given the increasing relevance of semantic interoperability in this context, this work presents the specification and development of a Web Ontology Service (WOS), based on the OGC Web Service Architecture specification, whose purpose is to facilitate the management and use of lexical ontologies. Additionally, this work shows how to integrate this service with Spatial Data Infrastructure discovery components in order to obtain a better classification of resources and an improvement in information retrieval performance.     

A Web Ontology Service to facilitate interoperability within a Spatial Data Infrastructure: Applicability to discovery

Ontologies are used within the context of Spatial Data Infrastructures to denote a formally represented knowledge that is used to improve data sharing and information retrieval. Given the increasing relevance of semantic interoperability in this context, this work presents the specification and development of a Web Ontology Service (WOS), based on the OGC Web Service Architecture specification, whose purpose is to facilitate the management and use of lexical ontologies. Additionally, this work shows how to integrate this service with Spatial Data Infrastructure discovery components in order to obtain a better classification of resources and an improvement in information retrieval performance.