David Martin

Bio: David Martin is an academic researcher from Nuance Communications. The author has contributed to research in topics: Medicine & Semantic Web Stack. The author has an hindex of 32, co-authored 91 publications receiving 10340 citations. Previous affiliations of David Martin include SRI International & Electronics and Telecommunications Research Institute.

On the complexity of the containment problem for conjunctive queries with built-in predicates

Abstract: When the inputs are conjunctive queries with #, 5, or < as built-in predicates, the query containment problem ‘is Qr 5 Qz?,, is I$-complete and, thus, highly intractable. In this paper, we investigate the impact of syntactic and structural conditions on the computational complexity of tho query containment problem for safe conjunctive queries with discquation # as a built-in predicate. In the case of Np~r~‘, conjunctive queries (no built-in predicates), it is known that the boundary between polynomial-time solvability and NP-completeness is crossed, when the number of occurrcnccs of any database predicate in Qr increases from two to three, We show here that, as regards safe conjunctivc qucrics with disequations, the same syntactic condition dolincatcs the boundary between membership in coNP and II?$completencss, Moreover, it is also known that the “pure” conjunctive query containment problem is solvable in polynomial time, if the hypergraph associated with the database predicates of Qz is acyclic. In contrast, we show that the vory samo structural condition does not lower the computational complexity of the containment problem for safe conjunctivc queries with disequations, that is, the problem remnins II~completc. We also analyze the computational complexity of the quary equivalence problem for conjunctive queries with disequations, when one of the two queries is fixed. We show that this problem can be DP-complete, where DP is the class of nil decision problems that are the conjunction of a problem in NP and a problem in coNP. It follows that, as regards conjunctive queries with disequations, the complexity of the query cquivalcncc problem may be higher than the complexity of the query containment problem, when one of the two qucrics is fixed.

BioSPICE: access to the most current computational tools for biologists.

Abstract: The goal of the BioSPICE program is to create a framework that provides biologists access to the most current computational tools. At the program midpoint, the BioSPICE member community has produced a software system that comprises contributions from approximately 20 participating laboratories integrated under the BioSPICE Dashboard and a methodology for continued software integration. These contributed software modules are the BioSPICE Dashboard, a graphical environment that combines Open Agent Architecture and NetBeans software technologies in a coherent, biologist-friendly user interface. The current Dashboard permits data sources, models, simulation engines, and output displays provided by different investigators and running on different machines to work together across a distributed, heterogeneous network. Among several other features, the Dashboard enables users to create graphical workflows by configuring and connecting available BioSPICE components. Anticipated future enhancements to BioSPICE incl...

Semantic Web Services, Part 2

Abstract: In part 2 of this Trends & Controversies installment, we continue exploring the state of the art, current practices, and future directions for Semantic Web services. SWS aims to bring Semantic Web technology - for representing, sharing, and reasoning about knowledge - to bear in Web service contexts. The objective is to enable a fuller, more flexible automation of service provision and use and the construction of more powerful tools and methodologies for working with services.

Accessing information and services on the DAML enabled web

Abstract: The DARPA Agent Markup Language (DAML) program aims to allow one to mark up web pages to indicate the meaning of their content; it is intended that the results delivered by a DAML-enabled browser will more closely match the intentions of the user than is possible with today's syntactically oriented search engines In this paper we present our vision of a DAML-enabled search architecture We present a set of queries of increasing complexity that should be answered efficiently in a SemanticWeb We describe several scenarios illustrating how queries are processed, identifying the main software components necessary to facilitate the search We examine the issue of inference in search, and we address how to characterize procedures and services in DAML, enabling a DAML query language to find web sites with specified capabilities

DAML-S: semantic markup for web services

Abstract: The Semantic Web should enable greater access not only to content but also to services on the Web. Users and software agents should be able to discover, invoke, compose, and monitor Web resources offering particular services and having particular properties. As part of the DARPA Agent Markup Language program, we have begun to develop an ontology of services, called DAML-S, that will make these functionalities possible. In this paper we describe the overall structure of the ontology, the service profile for advertising services, and the process model for the detailed description of the operation of services. We also compare DAML-S with several industry efforts to define standards for characterizing services on the Web.

QoS-aware middleware for Web services composition

Abstract: The paradigmatic shift from a Web of manual interactions to a Web of programmatic interactions driven by Web services is creating unprecedented opportunities for the formation of online business-to-business (B2B) collaborations. In particular, the creation of value-added services by composition of existing ones is gaining a significant momentum. Since many available Web services provide overlapping or identical functionality, albeit with different quality of service (QoS), a choice needs to be made to determine which services are to participate in a given composite service. This paper presents a middleware platform which addresses the issue of selecting Web services for the purpose of their composition in a way that maximizes user satisfaction expressed as utility functions over QoS attributes, while satisfying the constraints set by the user and by the structure of the composite service. Two selection approaches are described and compared: one based on local (task-level) selection of services and the other based on global allocation of tasks to services using integer programming.

Semantic Matching of Web Services Capabilities

Abstract: The Web is moving from being a collection of pages toward a collection of services that interoperate through the Internet. The first step toward this interoperation is the location of other services that can help toward the solution of a problem. In this paper we claim that location of web services should be based on the semantic match between a declarative description of the service being sought, and a description of the service being offered. Furthermore, we claim that this match is outside the representation capabilities of registries such as UDDI and languages such as WSDL.We propose a solution based on DAML-S, a DAML-based language for service description, and we show how service capabilities are presented in the Profile section of a DAML-S description and how a semantic match between advertisements and requests is performed.

Developing Multi-Agent Systems with JADE

Abstract: JADE (Java Agent Development Framework) is a software framework to make easy the development of multi-agent applications in compliance with the FIPA specifications. JADE can then be considered a middle-ware that implements an efficient agent platform and supports the development of multi agent systems. JADE agent platform tries to keep high the performance of a distributed agent system implemented with the Java language. In particular, its communication architecture tries to offer flexible and efficient messaging, transparently choosing the best transport available and leveraging state-of-the-art distributed object technology embedded within Java runtime environment. JADE uses an agent model and Java implementation that allow good runtime efficiency, software reuse, agent mobility and the realization of different agent architectures.

Service oriented architectures: approaches, technologies and research issues

Abstract: Service-oriented architectures (SOA) is an emerging approach that addresses the requirements of loosely coupled, standards-based, and protocol- independent distributed computing. Typically business operations running in an SOA comprise a number of invocations of these different components, often in an event-driven or asynchronous fashion that reflects the underlying business process needs. To build an SOA a highly distributable communications and integration backbone is required. This functionality is provided by the Enterprise Service Bus (ESB) that is an integration platform that utilizes Web services standards to support a wide variety of communications patterns over multiple transport protocols and deliver value-added capabilities for SOA applications. This paper reviews technologies and approaches that unify the principles and concepts of SOA with those of event-based programing. The paper also focuses on the ESB and describes a range of functions that are designed to offer a manageable, standards-based SOA backbone that extends middleware functionality throughout by connecting heterogeneous components and systems and offers integration services. Finally, the paper proposes an approach to extend the conventional SOA to cater for essential ESB requirements that include capabilities such as service orchestration, "intelligent" routing, provisioning, integrity and security of message as well as service management. The layers in this extended SOA, in short xSOA, are used to classify research issues and current research activities.