Interoperation among agent-based information systems through a communication acts ontology

Information technology is evolving from focusing on local systems to encompassing a more global interaction among multiple systems in enterprises and communities. On the one hand, new advances in the area of network communications have facilitated in some way the intercommunication among heterogeneous information systems located at different places. However, what is still missing is the possibility of a real and efficient interoperation among those systems in an open environment as the one favoured by Internet. On the other hand, agent technology provides platforms where cooperative work of information systems is concernable because of the software agents working on behalf of these information systems. But, nowadays that cooperation is in general restricted and requires a laborious a priori preparation. In this paper we present the features of a formal ontology that can play a relevant role in the development of a new kind of information systems interoperation frameworks. The ontology includes classes and properties for describing communication acts among agents. We claim that the communication acts ontology provides interoperability support due to the recognition of communication acts from one Agent Communication Language (acl) as instances of communication acts in another acl. Sometimes the comprehension will not be complete, but partial comprehension of the communication may be useful and preferable to the “not understood” answer given nowadays. Terms of the ontology are described as classes or properties using the Web Ontology Language owl.     

Towards open ontology learning and filtering

Open ontology learning is the process of extracting a domain ontology from a knowledge source in an unsupervised way. Due to its unsupervised nature, it requires filtering mechanisms to rate the importance and correctness of the extracted knowledge. This paper presents OntoCmaps, a domain-independent and open ontology learning tool that extracts deep semantic representations from corpora. OntoCmaps generates rich conceptual representations in the form of concept maps and proposes an innovative filtering mechanism based on metrics from graph theory. Our results show that using metrics such as Betweenness, PageRank, Hits and Degree centrality outperforms the results of standard text-based metrics (TF-IDF, term frequency) for concept identification. We propose voting schemes based on these metrics that provide a good performance in relationship identification, which again provides better results (in terms of precision and F-measure) than other traditional metrics such as frequency of co-occurrences. The approach is evaluated against a gold standard and is compared to the ontology learning tool Text2Onto. The OntoCmaps generated ontology is more expressive than Text2Onto ontology especially in conceptual relationships and leads to better results in terms of precision, recall and F-measure.     

基于网络课程本体的语义查询推理系统

针对网络课程知识点相对孤立、共享性与重用性差、学习资源查找困难、不能提供个性化服务等问题,提出使用基于本体查询推理的解决方法,设计了检索、查询和推理的功能模块和工作流程,并综合运用了Jena和SPARQL实现了相应的原型系统。通过具体的课程本体进行测试,验证了该解决方法的有效性和可行性。该系统能够将网络课程知识内容有机组织到一起,达到共享、重用的效果,可以提供个性化的学习服务,为进一步开发智能化的网络课程平台提供了条件。     

一种关系模式到OWL DL本体的翻译方法

本体技术是数据可以达到语义层次交换的关键,如何将当前各类数据形成本体知识库表示是一个非常重要的问题。针对这个问题,以一种关系模式到一种语义扩展ER模型的正确性可满足转换算法为基础,提出了一种通过数据库反向工程到OWL DL本体的翻译算法,说明了该算法使得转换是正确性可满足的,并实验实现验证了算法。     

Human-centered ontology engineering: The HCOME methodology

The fast emergent and continuously evolving areas of the Semantic Web and Knowledge Management make the incorporation of ontology engineering tasks in knowledge-empowered organizations and in the World Wide Web more than necessary. In such environments, the development and evolution of ontologies must be seen as a dynamic process that has to be supported through the entire ontology life cycle, resulting to living ontologies. The aim of this paper is to present the Human-Centered Ontology Engineering Methodology (HCOME) for the development and evaluation of living ontologies in the context of communities of knowledge workers. The methodology aims to empower knowledge workers to continuously manage their formal conceptualizations in their day-to-day activities and shape their information space by being actively involved in the ontology life cycle. The paper also demonstrates the Human Centered ONtology Engineering Environment, HCONE, which can effectively support this methodology. George VOUROS (B.Sc. Ph.D.) holds a B.Sc. in Mathematics, and a Ph.D. in Artificial Intelligence all from the University of Athens, Greece. Currently he is a Professor and Head of the Department of Information and Communication Systems Engineering, University of the Aegean, Greece, Director of the AI Lab and head of the Intelligent and Cooperative Systems Group (InCoSys). He has done research in the areas of Expert Systems, Knowledge management, Collaborative Systems, Ontologies, and Agent-based Systems. His published scientific work includes more than 80 book chapters, journal and national and international conference papers in the above-mentioned themes. He has served as program chair and chair and member of organizing committees of national and international conferences on related topics. Konstantinos KOTIS (B.Sc. Ph.D.) holds a B.Sc. in Computation from the University of Manchester, UK (1995), and a Ph.D. in Information Management from University of the Aegean, Greece (May, 2005). Currently, he is a member of the Intelligent and Cooperative Systems Group (InCoSys) and director of the Information Technology Department of the Prefecture of Samos, Greece. His research and published work concerns Knowledge management, Ontology Engineering and Semantic Web. He has lectured in several IT seminars and has served as member of program committees in international workshops.     

本体在E learning系统中的应用研究*

探讨了Elearning及本体,提出了基于本体的Elearning系统层次结构模型,并重点研究了本体在其中的应用：用于描述学习材料语义的内容本体,用于定义学习材料上下文的上下文本体以及用于在学习课程中组织学习材料的结构本体。     

A novel approach to generate MCQs from domain ontology: Considering DL semantics and open-world assumption

Ontologies are structures, used for knowledge representation, which model domain knowledge in the form of concepts, roles, instances and their relationships. This knowledge can be exploited by an assessment system in the form of multiple choice questions (MCQs). The existing approaches, which use ontologies expressed in the Web Ontology Language (OWL) for MCQ generation, are limited to simple concept related questions — “What is C?” or “Which of the following is an example of C?” (where $C$ is a concept symbol) — or analogy type questions involving roles. There are no efforts in the literature which make use of the terminological axioms in the ontology such as existential, universal and cardinality restrictions on concepts and roles for MCQ generation. Also, there are no systematic methods for generating incorrect answers (distractors) from ontologies. Distractor generation process has to be given much importance, since the generated distractors determine the quality and hardness of an MCQ. We propose two new MCQ generation approaches, which generate MCQs that are very useful and realistic in conducting assessment tests, and the corresponding distractor generating techniques. Our distractor generation techniques, unlike other methods, consider the open-world assumption, so that the generated MCQs will always be valid (falsity of distractors is ensured). Furthermore, we present a measure to determine the difficulty level (a value between 0 and 1) of the generated MCQs. The proposed system is implemented, and experiments on specific ontologies have shown the effectiveness of the approaches. We also did an empirical study by generating question items from a real-world ontology and validated our results with the help of domain experts.     

Repairing and reasoning with inconsistent and uncertain ontologies

With the development of semantic web, the quality and correctness of ontologies play more and more important roles in semantic representation and knowledge sharing. However, ontologies are often inconsistent and uncertain in real situations. Because of the difficulty in ensuring the quality of ontologies, there is an increasing need for dealing with the inconsistency and uncertainty in real-world applications of ontological reasoning and management. This paper adopts two methods to handle the inconsistent and uncertain ontologies: the first one is to repair the inconsistency, algorithms RIO and RIUO are proposed to compute the candidate repair set, the consistency of ontology could be recovered through deleting or modifying the axioms in candidate repair set; the second one is to develop a non-standard reasoning method to obtain meaningful answers, algorithms RMU and RMIU are proposed to perform query-specific reasoning methods for inconsistent and uncertain ontologies without changing the original ontologies. Finally the prototype system is constructed and the experiment results validate the usability and effectiveness of our approaches.     

Performance assessment of intelligent distributed systems through software performance ontology engineering (SPOE)

In the computer science community there is a growing interest in the field of Ambient Intelligent Systems. This systems surround their human users with computing and networking technology unobtrusively embedded in their environment. This technology is aimed to provide the users with useful information and to take action to make the environment more convenient for them. As the number of users increases the resources that make Ambient Intelligence possible can be easily saturated making the system unstable and projecting an image of poor QoS to the users. The main goal of this paper is to provide the means for the Ambient Intelligent Systems to monitor themselves and take corrective action automatically if performance starts to drop. Our approach uses a Performance Ontology that structures the knowledge about Software Performance Engineering, and a reasoning engine that acts like an expert system with the Performance Ontology as its foundation. The case study at the end shows the applicability of the developed techniques.     

Crossing the chasm between ontology engineering and application development: A survey

The adoption of Knowledge Graphs (KGs) by public and private organizations to integrate and publish data has increased in recent years. Ontologies play a crucial role in providing the structure for KGs, but are usually disregarded when designing Application Programming Interfaces (APIs) to enable browsing KGs in a developer-friendly manner. In this paper we provide a systematic review of the state of the art on existing approaches to ease access to ontology-based KG data by application developers. We propose two comparison frameworks to understand specifications, technologies and tools responsible for providing APIs for KGs. Our results reveal several limitations on existing API-based specifications, technologies and tools for KG consumption, which outline exciting research challenges including automatic API generation, API resource path prediction, ontology-based API versioning, and API validation and testing.     

Agent based intelligent search framework for product information using ontology mapping

The Semantic Web and Web services provide many opportunities in various applications such as product search and comparison in electronic commerce. We implemented an intelligent meta-search and recommendation system for products through consideration of multiple attributes by using ontology mapping and Web services. Under the assumption that each shopping site offers product ontology and product search service with Web services, we proposed a meta-search framework to configure a customer’s search intent, make and dispatch proper queries to each shopping site, evaluate search results from shopping sites, and show the customer the relevant product list with associated rankings. Ontology mapping is used for generating proper queries for shopping sites that have different product categories. We also implemented our framework and performed empirical evaluation of our approach with two leading shopping sites in the world.     

Terminological ontology learning and population using latent Dirichlet allocation

The success of Semantic Web will heavily rely on the availability of formal ontologies to structure machine understanding data. However, there is still a lack of general methodologies for ontology automatic learning and population, i.e. the generation of domain ontologies from various kinds of resources by applying natural language processing and machine learning techniques In this paper, the authors present an ontology learning and population system that combines both statistical and semantic methodologies. Several experiments have been carried out, demonstrating the effectiveness of the proposed approach.     

Supporting concurrent ontology development: Framework, algorithms and tool

We propose a novel approach to facilitate the concurrent development of ontologies by different groups of experts. Our approach adapts Concurrent Versioning, a successful paradigm in software development, to allow several developers to make changes concurrently to an ontology. Conflict detection and resolution are based on novel techniques that take into account the structure and semantics of the ontology versions to be reconciled by using precisely-defined notions of structural and semantic differences between ontologies and by extending state-of-the-art ontology debugging and repair techniques. We also present ContentCVS, a system that implements our approach, and a preliminary empirical evaluation which suggests that our approach is both computationally feasible and useful in practice.     

A qualitative evaluation of evolution of a learning analytics tool

LOCO-Analyst is a learning analytics tool we developed to provide educators with feedback on students learning activities and performance. Evaluation of the first version of the tool led to the enhancement of the tool’s data visualization, user interface, and supported feedback types. The second evaluation of the improved tool allowed us to see how the improvements affected the users’ perceived value of the tool. Here, we present the qualitative results of our two evaluations and discuss important lessons learned stemming from the comparison of the two studies. The results show that educators find the kinds of feedback implemented in the tool informative and they value the mix of textual and graphical representations of different kinds of feedback provided by the tool.     

智能服务--Web服务和语义Web集成研究

现有Web主要是为人使用Web上的内容设计,如何自动发现、执行、组合及互操作Web上的信息,提供智能服务,是Web服务努力的方向,Web服务虽然也制定了发现、描述、信息交换的标准,但这些标准不支持智能服务,其原因是现有Web服务缺乏清楚的语义标记,该文提出将语义Web技术和Web服务结合来实现智能服务的思想,即为Web服务增加语义标记以实现Web服务的智能性,并就其可行性进行了阐述,最后给出了具体实现的方法。     

语义万维网的概念、方法及应用

近两年来,语义万维网(semanticweb)的研究逐渐引起了知识表示、逻辑编程、信息系统集成、web开发等各个领域的广泛关注。笔者在研究万维网环境下的领域知识表示及语义共享模式的过程中,阅读了大量有关语义万维网的文献资料,认为,语义万维网的研究将对传统web上信息的发布、存储和处理方式产生一场变革,但是语义万维网的概念、思想和方法还处于形成阶段,国内少有综述性的文献,对语义万维网及其相关技术的认识比较模糊。该文分析了语义万维网的起源、概念、技术框架,总结了语义万维网及相关工具的现状,并讨论了语义万维网技术在智能信息检索、企业间数据交换、知识管理以及万维网服务中的应用。