{"title":"The role of ontologies in the verification and validation of knowledge based systems","authors":"Trevor J. M. Bench-Capon","doi":"10.1109/DEXA.1998.707381","DOIUrl":"https://doi.org/10.1109/DEXA.1998.707381","url":null,"abstract":"The author gives some preliminary examination of the ways in which an ontology-an explicit specification of the conceptualisation of the domain-can support the verification and validation of a knowledge based system. The discussion is focussed on a simple, well known example, relating to the identification of animals. Key elements of the support provided by the ontology relate to: attempting to give coherence to the domain conceptualisation; making the role of experts in verification and validation more structured and less at the mercy of interpretation; constraining the number of test cases required to give good coverage of the possible cases; and structuring the testing to give better assurance of its efficacy, and a possible basis for greater automation of the testing process. Finally the author makes some brief remarks on the relation between the ontology of a knowledge based system, and a database and its schema.","PeriodicalId":194923,"journal":{"name":"Proceedings Ninth International Workshop on Database and Expert Systems Applications (Cat. No.98EX130)","volume":"380 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115477048","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"An extended query reformulation technique using materialized views","authors":"Jae-young Chang, Sang-goo Lee","doi":"10.1109/DEXA.1998.707517","DOIUrl":"https://doi.org/10.1109/DEXA.1998.707517","url":null,"abstract":"Materialized views offer opportunities for significant performance gain in query evaluation by providing fast access to pre-computed data. The question of when and how to use a materialized view in processing a given query is a difficult one attracting a significant amount of research. In previous works only one-to-one or containment mapping from views to a query has been used and, as a result, certain potentially useful materialized views were excluded from consideration. Proposed in this paper are new ways of utilizing materialized views in answering a query. Views including relations not referred to in an original query, which were excluded in previous works, are utilized. Attributes missing from a view can be recovered under certain conditions. We present the conditions where a view may be used in these ways and algorithms that can effectively test these conditions and reformulate the query. The proposed conditions and corresponding algorithms provide a significant and practical extension to the usability of materialized views in query processing.","PeriodicalId":194923,"journal":{"name":"Proceedings Ninth International Workshop on Database and Expert Systems Applications (Cat. No.98EX130)","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129123144","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Extensible multimedia class library for object-oriented database systems","authors":"Takayuki Saeki, M. Namiuchi","doi":"10.1109/DEXA.1998.707511","DOIUrl":"https://doi.org/10.1109/DEXA.1998.707511","url":null,"abstract":"We have designed an extensible and customizable multimedia database class library using the concept of the object-oriented framework, and implemented it using our object-oriented database management system PERCIO. Its extensibility is achieved by encapsulating frequently modified functions into three submodules; namely media storage, retrieval and processing, and by providing them as classes that can be extended by making subclasses. The evaluation results indicate that the class library is customizable by addition without modification to it, source codes, and it can sharply reduce the amount of source code required to incorporate a new retrieval function.","PeriodicalId":194923,"journal":{"name":"Proceedings Ninth International Workshop on Database and Expert Systems Applications (Cat. No.98EX130)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130015111","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A software architecture for workflow management systems","authors":"S. Jablonski","doi":"10.1109/DEXA.1998.707490","DOIUrl":"https://doi.org/10.1109/DEXA.1998.707490","url":null,"abstract":"This research paper contributes a software architecture for workflow management systems. The architecture is separated into two pieces: the implementation model comprises a system-independent logical model of a workflow management system, i.e. the major components and their interrelationships are described. The implementation architecture shows how this model is enacted.","PeriodicalId":194923,"journal":{"name":"Proceedings Ninth International Workshop on Database and Expert Systems Applications (Cat. No.98EX130)","volume":"85 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116476234","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"An information model for nomadic environments","authors":"A. Bond, M. Gallagher, J. Indulska","doi":"10.1109/DEXA.1998.707431","DOIUrl":"https://doi.org/10.1109/DEXA.1998.707431","url":null,"abstract":"We present a software architecture which facilitates nomadic computing in an open distributed computing environment. We introduce a model for the description of mobile objects (users, computers and application objects) and their types. The descriptions create an information base for protocols managing mobility of the mobile objects. We present an architecture of servers which extend a distributed computing environment to implement these mobility management protocols.","PeriodicalId":194923,"journal":{"name":"Proceedings Ninth International Workshop on Database and Expert Systems Applications (Cat. No.98EX130)","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122486199","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sarah Brown, Richard Vallas, Mohamed T. Ibrahim, A. Al-Zobaidie
{"title":"Object design of a distributed client/server system","authors":"Sarah Brown, Richard Vallas, Mohamed T. Ibrahim, A. Al-Zobaidie","doi":"10.1109/DEXA.1998.707521","DOIUrl":"https://doi.org/10.1109/DEXA.1998.707521","url":null,"abstract":"This paper describes our practical experience in developing an object-oriented design and in implementing a prototype distributed client/server application. The system is described in terms of its individual components features and their interaction with other components via middleware. The prototype was coded in Java and employs two middleware technologies for clients/servers interaction. The main middleware employed is CORBA that has enabled us to achieve server location transparency by using CORBA's naming service. CORBA also provides a protocol to allow the communication between the components once binding between them occurred. The second middleware technology used was Java Database Connectivity (JDBC) which provided the means to query and maintain a distributed database. The features of JDBS and the way in which they were applied to the requirements of the application are also described. The prototype application was developed using Visigenic's VisiBroker and the generated classes were then extended using the Java SDK. The JDBC middleware layer was used to provide the link between the Java based servers and the databases. The main contribution of this work is mainly practical and is twofold. Firstly, we describe and share our experience in designing, implementing a prototype application using CORBA/JDBC, as well as our findings relating to performance aspects of the prototype. Secondly, and in the light of the results obtained, we evaluate our approach, lessons learned and suggest possible improvements and guidelines for developing similar systems and/or prototypes.","PeriodicalId":194923,"journal":{"name":"Proceedings Ninth International Workshop on Database and Expert Systems Applications (Cat. No.98EX130)","volume":"142 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116576138","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Multi-level browsing for efficient image transmission","authors":"P. D. Le, B. Srinivasan, S. Kulkarni","doi":"10.1109/DEXA.1998.707427","DOIUrl":"https://doi.org/10.1109/DEXA.1998.707427","url":null,"abstract":"Multimedia applications such as distributed digital libraries, digital databases, teleshopping and telebrowsing systems are expected to deliver as minimum data as needed and allow users to quickly browse through images located in remote databases. Currently users often experience delays since a large amount of multimedia data such as images has to be transmitted across networks. Existing network technologies are not advanced enough (many places still use slow links) and the number of users is growing at a rapid pace. This places a further demand on the network bandwidth. Usually different users and applications may require images at different levels of quality but existing browsers only deliver the available data (often pre-compressed data) and do not allow users to specify the quality level of images they need, hence extra data has to be transmitted unnecessarily. The response time can be improved if the requested images are delivered at the requested quality. This paper proposes a framework for multi-level browsers and network graphic user interfaces based on the notion that the users should be allowed to specify the level of quality of the image they need and suitable compression techniques should be employed to minimise needed image data before transmission. Images can be either precompressed at the desired quality levels or further compressed to reduce their volume before they are delivered.","PeriodicalId":194923,"journal":{"name":"Proceedings Ninth International Workshop on Database and Expert Systems Applications (Cat. No.98EX130)","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131720937","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Kengo Koiso, Kenji Kawakatsu, Katsumi Tanaka, Takehisa Mori
{"title":"Dynamic generation of virtual spaces and incremental query formulation using spatial browsing","authors":"Kengo Koiso, Kenji Kawakatsu, Katsumi Tanaka, Takehisa Mori","doi":"10.1109/DEXA.1998.707520","DOIUrl":"https://doi.org/10.1109/DEXA.1998.707520","url":null,"abstract":"First, we will describe the concept and implementation issues of our \"Dynamically Extendible Museum\", a system which enables the users to create their favorite virtual spaces dynamically and incrementally from databases in order to present the objects retrieved by the user's queries. Second, we propose a mechanism to incrementally formulate user's query by letting the user select objects in a virtual space. We also discuss implementation issues of our prototype systems using museum metaphors to demonstrate our ideas.","PeriodicalId":194923,"journal":{"name":"Proceedings Ninth International Workshop on Database and Expert Systems Applications (Cat. No.98EX130)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134221024","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Computing conspiracies [data integrity]","authors":"P. Elsas, P. Vries, R. V. D. Riet","doi":"10.1109/DEXA.1998.707411","DOIUrl":"https://doi.org/10.1109/DEXA.1998.707411","url":null,"abstract":"The concept of 'segregation of duties' is well-known in both organisational and security contexts. For example, the Clark-Wilson model stresses the importance of such a policy appropriate for regulating the involvement of subjects in acting upon business information and business values. However, it gives no guidelines on how to distinguish a proper policy from an improper one. Furthermore, the discipline of auditing has developed numerous schemes for segregation of duties. In this paper we use a model that allows quantification of-and reasoning about-audit-technical segregation of duties. Our approach is based on normative ('Soll') and actual ('Ist') specifications of a company's circular flow of business values in terms of enriched Petri nets. In this type of Petri net the markers represent money, goods, debts and registrations of these business values, the places represent their buffer locations and the transitions represent transformation procedures. Associated to these Petri net elements are agents and their authorisations and abilities. Undetectable use of company assets can now be modelled in the '1st' net by the general Petri net notion of 'T-invariant'. The design of a proper scheme for segregation of duties then reduces to maximisation of the number of agents that need to be minimally involved in order to establish a firing of such a T-invariant.","PeriodicalId":194923,"journal":{"name":"Proceedings Ninth International Workshop on Database and Expert Systems Applications (Cat. No.98EX130)","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131657883","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Distributed optimization of cyclic queries with parallel semijoins","authors":"F. Najjar, Y. Slimani","doi":"10.1109/DEXA.1998.707487","DOIUrl":"https://doi.org/10.1109/DEXA.1998.707487","url":null,"abstract":"We consider the problem of finding (possibly optimal) semijoin sequences that (fully) reduce the relations referenced in a cyclic query graph. We propose a combination of parallel and sequential semijoin operations to minimize the amount of data transmission in distributed query processing. We report on experiments that show that our approach is not only efficient but also effective in reducing the total amount of data transmission.","PeriodicalId":194923,"journal":{"name":"Proceedings Ninth International Workshop on Database and Expert Systems Applications (Cat. No.98EX130)","volume":"236 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131820705","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}