7863527
Enforcing policies in pervasive environments
This work presents an architecture and a proof of concept implementation of a security infrastructure for mobile devices in an infrastructure based pervasive environment. The security infrastructure primarily consists of two parts, the policy engine and the policy enforcement mechanism. Each mobile device within a pervasive environment is equipped with its own policy enforcement mechanism and is responsible for protecting its resources. A mobile device consults the nearest policy server, notifies its current state including its present user, network presence, other accessible devices and location information if available. Using this information the policy server queries the "Rei" engine to dynamically create a policy certificate and issues it to the requesting device. The system wide policy is described in a semantic language "Rei", a lightweight and extensible language which is able to express comprehensive policies using domain specific information. The "Rei" policy engine is able to dynamically decide what rights, prohibitions, obligations, dispensations an actor has on the domain actions. A policy certificate is created and issued to the device. The policy certificate contains a set of granted permissions and a validity period and scope within which the permissions are valid. The policy certificate can be revoked by the policy enforcer based on expiration of the validity period or a combination of timeout, loss of contact with an assigned network. X.509 based public key infrastructure is used to provide identification and authentication.
31295380
Intelligent Agents for Mobile and Embedded Devices
The pervasive computing environments of the near future will involve the interactions, coordination and cooperation of numerous, casually accessible, and often invisible computing devices. These devices, whether carried on our person or embedded in our homes, businesses and classrooms, will connect via wireless and wired links to one another and to the global networking infrastructure. The result will be a networking milieu with a new level of openness. The localized and dynamic nature of their interactions raises many new issues that draw on and challenge the disciplines of agents, distributed systems, and security. This paper describes recent work by the UMBC Ebiquity research group which addresses some of these issues.
8623137
Semantic analytics on social networks: experiences in addressing the problem of conflict of interest detection
In this paper, we describe a Semantic Web application that detects Conflict of Interest (COI) relationships among potential reviewers and authors of scientific papers. This application discovers various 'semantic associations' between the reviewers and authors in a populated ontology to determine a degree of Conflict of Interest. This ontology was created by integrating entities and relationships from two social networks, namely "knows," from a FOAF (Friend-of-a-Friend) social network and "co-author," from the underlying co-authorship network of the DBLP bibliography. We describe our experiences developing this application in the context of a class of Semantic Web applications, which have important research and engineering challenges in common. In addition, we present an evaluation of our approach for real-life COI detection.
14330906
Creating Context-Aware Software Agents
Sharing ontologies, sensing context and reasoning are crucial to the realization of context-aware software agents. This document de- scribes our efforts in using the Resource Description Framework (RDF) and Prolog Forward Chaining (Pfc) system to provide support for ontology sharing and reasoning in the CoolAgent Recommendation System (CoolAgent RS), a context-aware multi-agent system. We also describes the implementation of the CoolAgent RS document and cuisine recommendation services that provide tailored services by exploiting user's context.
1962537
Finding and Ranking Knowledge on the Semantic Web
Swoogle helps software agents and knowledge engineers find Semantic Web knowledge encoded in RDF and OWL documents on the Web. Navigating such a Semantic Web on the Web is difficult due to the paucity of explicit hyperlinks beyond the namespaces in URIrefs and the few inter-document links like rdfs:seeAlso and owl:imports. In order to solve this issue, this paper proposes a novel Semantic Web navigation model providing additional navigation paths through Swoogle's search services such as the Ontology Dictionary. Using this model, we have developed algorithms for ranking the importance of Semantic Web objects at three levels of granularity: documents, terms and RDF graphs. Experiments show that Swoogle outperforms conventional web search engine and other ontology libraries in finding more ontologies, ranking their importance, and thus promoting the use and emergence of consensus ontologies.
468262
Collaborative joins in a pervasive computing environment
Abstract.We present a collaborative query processing protocol based on the principles of Contract Nets. The protocol is designed for pervasive computing environments where, in addition to operating on limited computing and battery resources, mobile devices cannot always rely on being able to access the wired infrastructure. Devices, therefore, need to collaborate with each other in order to obtain data otherwise inaccessible due to the nature of the environment. Furthermore, by intelligently using answers cached by peers, devices can reduce their computation cost. We show the effectiveness of our approach by evaluating performance of devices querying for data while moving in a citylike environment.
2954113
Tree Adjunct Grammars
In this paper, a tree generating system called a tree adjunct grammar is described and its formal properties are studied relating them to the tree generating systems of Brainerd (Information and Control14 (1969), 217-231) and Rounds (Mathematical Systems Theory 4 (1970), 257-287) and to the recognizable sets and local sets discussed by Thatcher (Journal of Computer and System Sciences1 (1967), 317-322; 4 (1970), 339-367) and Rounds. Linguistic relevance of these systems has been briefly discussed also.
6625273
Wave-pipelined 2-slot time division multiplexed (WP/2-TDM) routing
The ever-increasing number of transistors on a chip has resulted in very large scale integration (VLSI) systems whose performance and manufacturing costs are driven by on-chip wiring needs. This paper proposes a low overhead wave-pipelined two-slot time division multiplexed (WP/2-TDM) routing technique that harnesses the inherent intra-clock period wire idleness to implement wire sharing in combination with wave-pipelined circuit techniques. It is illustrated in this paper that WP/2-TDM routing can be readily incorporated into future gigascale integration (GSI) systems to reduce the number of interconnect routing channels in an attempt to contain escalating manufacturing costs. Two case studies, one at the circuit level and one at the system level, are presented to illustrate the advantages of WP/2-TDM routing. The circuit level implementation exhibits more than 40% reduction in wire area, a 30% reduction in silicon area with no increase in dynamic power and no loss of throughput performance.
11638124
Measuring benchmark similarity using inherent program characteristics
This paper proposes a methodology for measuring the similarity between programs based on their inherent microarchitecture-independent characteristics, and demonstrates two applications for it: 1) finding a representative subset of programs from benchmark suites and 2) studying the evolution of four generations of SPEC CPU benchmark suites. Using the proposed methodology, we find a representative subset of programs from three popular benchmark suites - SPEC CPU2000, MediaBench, and MiBench. We show that this subset of representative programs can be effectively used to estimate the average benchmark suite IPC, L1 data cache miss-rates, and speedup on 11 machines with different ISAs and microarchitectures - this enables one to save simulation time with little loss in accuracy. From our study of the similarity between the four generations of SPEC CPU benchmark suites, we find that, other than a dramatic increase in the dynamic instruction count and increasingly poor temporal data locality, the inherent program characteristics have more or less remained unchanged
3265918
Anchoring a Lexicalized Tree-Adjoining Grammar for Discourse
We here explore a ``fully'' lexicalized Tree-Adjoining Grammar for discourse that takes the basic elements of a (monologic) discourse to be not simply clauses, but larger structures that are anchored on variously realized discourse cues. This link with intra-sentential grammar suggests an account for different patterns of discourse cues, while the different structures and operations suggest three separate sources for elements of discourse meaning: (1) a compositional semantics tied to the basic trees and operations; (2) a presuppositional semantics carried by cue phrases that freely adjoin to trees; and (3) general inference, that draws additional, defeasible conclusions that flesh out what is conveyed compositionally.
5320074
Using Lexicalized Tags for Machine Translation
Lexicalized Tree Adjoining Grammar (LTAG) is an attractive formalism for linguistic description mainly because of its extended domain of locality and its factoring recursion out from the domain of local dependencies (Joshi, 1985, Kroch and Joshi, 1985, Abeille, 1988). LTAG's extended domain of locality enables one to localize syntactic dependencies (such as filler-gap), as well as semantic dependencies (such as predicate-arguments). The aim of this paper is to show that these properties combined with the lexicalized property of LTAG are especially attractive for machine translation.The transfer between two languages, such as French and English, can be done by putting directly into correspondence large elementary units without going through some interlingual representation and without major changes to the source and target grammars. The underlying formalism for the transfer is "synchronous Tree Adjoining Grammars" (Shieber and Schabes [1990]). Transfer rules are stated as correspondences between nodes of trees of large domain of locality which are associated with words. We can thus define lexical transfer rules that avoid the defects of a mere word-to-word approach but still benefit from the simplicity and elegance of a lexical approach.We rely on the French and English LTAG grammars (Abeille [1988], Abeille [1990 (b)], Abeille et al. [1990], Abeille and Schabes [1989, 1990]) that have been designed over the past two years jointly at University of Pennsylvania and University of Paris 7-Jussieu.