Functional querying in graph databases

Abstract The paper is focused on a functional querying in graph databases. We consider labelled property graph model and mention also the graph model behind XML databases. An attention is devoted to functional modelling of graph databases both at a conceptual and data level. The notions of graph conceptual schema and graph database schema are considered. The notion of a typed attribute is used as a basic structure both on the conceptual and database level. As a formal approach to declarative graph database querying a version of typed lambda calculus is used. This approach allows to use a logic necessary for querying, arithmetic as well as aggregation function. Another advantage is the ability to deal with relations and graphs in one integrated environment

Mobile Constraints For Semantic Web Applications

We present a framework for semantic web applications based on constraint interchange and processing. At the core of the framework is a well-established semantic data model (P/FDM) with an associated expressive constraint language (Colan). To allow data instances to be transported across a network, we map our data model to the RDF Schema specification. To allow constraints to be transported, we define a Constraint Interchange Format (CIF) in the form of an RDF Schema for Colan, allowing each constraint to be defined as a resource in its own right. We show that, because Colan is essentially a syntacticallysugared form of first-order logic, and P/FDM is based on the widelyused extended ER model, our CIF is actually very widely applicable and reusable. Finally, we outline a set of services for constraint fusion and solving, which are particularly applicable to business-to-business e-commerce applications. These services are accessible using the CIF

Macromolecular structure information and databases

The current status and future outlook of macromolecular structure databases and information handling, with particular reference to European databases, are reviewed, Issues concerning the efficiency with which data are represented, validated, archived and accessed are discussed in view of the fast growing body of information on structures of biological macromolecules

Monitoring, Policing and Trust for Grid-Based Virtual Organisations

A key challenge in Grid Computing is the ability to create reliable and scalable virtual organisations (VOs) which operate in an open, dynamic and competitive environment. In response, in the CONOISE-G project, we are developing an infrastructure to support robust and resilient virtual organisation formation and operation. Specifically, CONOISE-G provides mechanisms to assure effective operation of agent-based VOs in the face of disruptive and potentially malicious entities in dynamic, open and competitive environments. In this paper, we describe the architecture of the CONOISE-G system, and provide details of its implementation

CONOISE-G: Agent-based virtual organisations for the Grid

The ability to create reliable and scalable virtual organisations (VOs) on demand in a dynamic, open and competitive environment is one of the challenges that underlie Grid computing. In response, in the CONOISE-G project, we are developing an infrastructure to support robust and resilient virtual organisation formation and operation. Specifically, CONOISE-G provides mechanisms to assure effective operation of agent-based VOs in the face of disruptive and potentially malicious entities in dynamic, open and competitive environments. In this paper, we describe the CONOISE-G system, outline its use in the context of VO formation and perturbation, and review current efforts to progress the work to deal with unreliable information sources

The KRAFT Architecture for Knowledge Fusion and Transformation

This paper describes the KRAFT architecture which supports the fusion of knowledge from multiple, distributed, heterogeneous sources. The architecture uses constraints as a common knowledge interchange format, expressed against a common ontology. Knowledge held in local sources can be tranformed into the common constraint language, and fused with knowledge from other sources. The fused knowledge is then used to solve some problem or deliver some information to a user. Problem-solving in KRAFT typically exploits pre-existing constraint solvers. KRAFT uses an open and flexible agent architecture in which knowledge sources, knowledge fusing entities, and users are all represented by independent KRAFT agents, communicating using a messaging protocol. Facilitator agents perform matchmaking and brokerage services between the various kinds of agent. KRAFT i