Federation views as a basis for querying and updating database federations

This paper addresses the problem of how to query and update so-called database federations. A database federation provides for tight coupling of a collection of heterogeneous component databases into a global integrated system. This problem of querying and updating a database federation is tackled by describing a logical architecture and a general semantic framework for precise specification of such database federations, with the aim to provide a basis for implementing a federation by means of relational database views. Our approach to database federations is based on the UML/OCL data model, and aims at the integration of the underlying database schemas of the component legacy systems to a separate, newly defined integrated database schema. One of the central notions in database modelling and in constraint specifications is the notion of a database view, which closely corresponds to the notion of derived class in UML. We will employ OCL (version 2.0) and the notion of derived class as a means to treat (inter-)database constraints and database views in a federated context. Our approach to coupling component databases into a global, integrated system is based on mediation. The first objective of our paper is to demonstrate that our particular mediating system integrates component schemas without loss of constraint information. The second objective is to show that the concept of relational database view provides a sound basis for actual implementation of database federations, both for querying and updating purposes.

UNDERSTANDING PREPOSITIONS THROUGH COGNITIVE GRAMMAR. A CASE OF IN

Poly - semantic nature of prepositions has been discussed in linguistic literature and confirmed by language data. In the majority of research within cognitive linguistics prepositions have been approached as predicates organising entities in space, with less attention paid to the search for a meaning schema sanctioning the numerous uses. Cognitive Grammar analytic tools allow for the analysis which results in discovering one meaning schema sanctioning the uses of the English preposition in. The present analysis is based on the assumption that the meaning schema of in profiles a relation of conceptual enclosure between two symbolic structures, one of which conceptually fits in the other. Accordingly, I argue that the speaker employs in to structure a real scene not because one element of the scene can physically enclose the other one, but due to conceptual ‘fitting in’ holding between the predication ‘preceding’ the preposition and the one that ‘follows’. In formal terms, the usage of in is conditioned and sanctioned by compatibility of active zones in the predications used to form the complex language expression involved. Peculiarities of physical organization may be ignored in such conceptualisation, though the speaker can choose to encode all peculiarities of physical organisation of real world objects employing different linguistic devices

XML for Domain Viewpoints

Within research institutions like CERN (European Organization for Nuclear Research) there are often disparate databases (different in format, type and structure) that users need to access in a domain-specific manner. Users may want to access a simple unit of information without having to understand detail of the underlying schema or they may want to access the same information from several different sources. It is neither desirable nor feasible to require users to have knowledge of these schemas. Instead it would be advantageous if a user could query these sources using his or her own domain models and abstractions of the data. This paper describes the basis of an XML (eXtended Markup Language) framework that provides this functionality and is currently being developed at CERN. The goal of the first prototype was to explore the possibilities of XML for data integration and model management. It shows how XML can be used to integrate data sources. The framework is not only applicable to CERN data sources but other environments too.Comment: 9 pages, 6 figures, conference report from SCI'2001 Multiconference on Systemics & Informatics, Florid

UNDERSTANDING THE RELATIONSHIP BETWEEN PRODUCT SPECIFICATIONS AND COORDINATION IN AGRI-BUSINESS SUPPLY CHAINS: AN EXAMINATION OF THE NEW ZEALAND MEAT INDUSTRY

Two phenomena are occurring simultaneously within the agribusiness sector: customers are requiring tighter product specifications and agricultural chains are becoming more coordinated. However, the exact relationship between these two phenomena is not clear. This research explores that relationship. Five New Zealand fresh meat chains were the focus of multiple case-study research, which used a chain-level (multi-dyadic) approach. Chains were assessed as to the nature of product specifications demanded at the end-customer level, as well as to the nature of inter-firm relationships. Interestingly, tighter product specifications in themselves do not lead to more coordinated chains; coordination seems to be linked to the level of effort required to meet product specifications.Industrial Organization, Livestock Production/Industries,

Data integration through service-based mediation for web-enabled information systems

The Web and its underlying platform technologies have often been used to integrate existing software and information systems. Traditional techniques for data representation and transformations between documents are not sufficient to support a flexible and maintainable data integration solution that meets the requirements of modern complex Web-enabled software and information systems. The difficulty arises from the high degree of complexity of data structures, for example in business and technology applications, and from the constant change of data and its representation. In the Web context, where the Web platform is used to integrate different organisations or software systems, additionally the problem of heterogeneity arises. We introduce a specific data integration solution for Web applications such as Web-enabled information systems. Our contribution is an integration technology framework for Web-enabled information systems comprising, firstly, a data integration technique based on the declarative specification of transformation rules and the construction of connectors that handle the integration and, secondly, a mediator architecture based on information services and the constructed connectors to handle the integration process

Can supply chain's coordination mechanisms include small holders? Insight from an empirical work in Costa Rica.

Small holders' agriculture is currently facing new stakes due to State's withdrawal from agricultural support and to higher market requests for producing agricultural products. Different coordination mechanisms can be observed inside the supply chains involving farmers, farmers' organizations, and others stakeholders. They depend on the nature of the product, the characteristics of the stakeholders involved, the technical specifications related to the transactions, and the institutional environment. Relying on a comparative case study methodology, the paper analyzes the consequences of different coordination mechanisms on inclusion or exclusion of small farmers in the northern region of Costa Rica. Market coordination could be an efficient way to integrate farmers in supply chains in the case of low technical specifications and of existence of adequate selling mechanisms. Hybrid coordination is the main mechanism and facilitates the inclusion of small farmers, depending on the farmers' organizations capacities to negotiate adequate rules. In some situations hybrid coordination with captive relationships could occur but leads to a more or less rapid exclusion process.supply chain, small holders, farmers, contracting, coordination, Costa Rica, Agribusiness,

Viewpoint Development of Stochastic Hybrid Systems

Nowadays, due to the explosive spreading of networked and highly distributed systems, mastering system complexity becomes a critical issue. Two development and verification paradigms have become more popular: viewpoints and randomisation. The viewpoints offer large freedom and introduce concurrency and compositionality in the development process. Randomisation is now a traditional method for reducing complexity (comparing with deterministic models) and it offers finer analytical analysis tools (quantification over non-determinism, multi-valued logics, etc). In this paper, we propose a combination of these two paradigms introducing a viewpoint methodology for systems with stochastic behaviours