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The purpose of this paper is to assess the impact of timer-based burst assembly algorithms for TCP traffic. We present an analysis for short, medium and long assembly times and investigate segment and flow distribution over the assembled bursts. Further, we also analyze their impact on the congestion window evolution and on the effective throughput achieved. It has been found out that short assembly times are ideally suitable for sources with small congestion windows, allowing for a speed up, while large assembly times yield a lower throughput variation among the individual assembled flows. For long assembly times, the transfer of more segments from the same source is trading off the increase of the burstification delay but no throughput gain is obtained. However, large assembly times smooth out individual flow performance and provide a significant lower variation of throughput. To this end, in this paper, we propose a new adaptive burst assembly algorithm that dynamically assigns flows to different burstifiers based on their instant window size. [ABSTRACT FROM AUTHOR]

This paper proposes 80Gb/s multi-wavelength optical packet switching(OPS) using a PLZT switch. The Multi-wavelength OPS Network can achieve low implementation costs compared to existing OPS networks in which the number of wavelengths is large. In this network, the header is processed separately from the payload. The payload is divided into multiple segments. Each segment is then encoded into different wavelengths. After assignment of wavelength to each payload segment, payload segments are multiplexed into an optical signal which is then transmitted through an optical fiber. Therefore, the number of components required for intermediate node functionality stays the same for the number of wavelengths used for payload transmission. This paper shows a fundamental experiment of the Multi-wavelength OPS network using a PLZT switch. PLZT switch provide a fast optical switching with low noise, independent polarization, and low drive voltage. In this paper, we describe the detail of the experiments and results. [ABSTRACT FROM AUTHOR]

The implementation of service-oriented device architectures (SODA) suffers from restrictions that are imposed by the use of existing syntactic technologies. Related problems include data and message-level heterogeneities among interoperating services, insufficient search and discovery of exposed services and inadequate web process composition. In this paper we propose an approach for introducing semantics in a SODA environment. Specifically we examine the introduction of data, functional and behavioural semantics and the role they play in a semantically-enabled SODA (SeSODA) pervasive environment. We put special emphasis in data semantics. We present the architecture of an OSGi-based SeSODA implementation, analyse the most critical components of this architecture and discuss implementation issues. [ABSTRACT FROM AUTHOR]

This paper presents a mobile system that supports young students learning history at an archaeological site. It adopts gameplay as a novel and effective technique particularly suited for learning through mobile systems (m-learning). From a technological point of view, the main novelty of our system is its slim architecture. Minimal investments are required because the system runs on the students' own cellular phones. Experimental studies indicate that gameplay is able to trigger a desire to learn more about ancient history and to make archaeological visits more exciting and learning about the past more effective. [ABSTRACT FROM AUTHOR]

Service Oriented Architecture (SOA) has been developed to enhance the integration of various systems to allow organizations to be more flexible in case of business changes. This paper will explain a top-down method in which Business Process Models can lead to a basic service orientation of business functions. This will be shown based on the principles of Model-Driven Architecture (MDA). Without model support, the translation of business needs into executable code to support IT developments is rather hard and mostly impossible. In this paper, we motivate the need for this approach as a means of focusing importance on modeling, a key enabler of communication between business analysts and IT developers. [ABSTRACT FROM AUTHOR]

Context is typically viewed at as meta-data that supplements the ‘real' data of an application. In this paper, we contrast and compare the concepts of context in four different applications. We show that our notion of context needs to be extended and that wider and more flexible notions need to be supported. In particular, a key issue is how to provide systems that support computation in regard to any context. [ABSTRACT FROM AUTHOR]

In this paper, WSBL (Web Service Business Library) is proposed as a solution for problems above mentioned, of any company which offers financial services, by combining agents' theory, web services and grid computing. After explaining the solution, this paper presents an example of a web service that prices a weather derivative using the computing power of a grid, but could be easily extended to any financial product. This approach would enable the bank to have only one library for pricing all products running in one grid giving service to all of the trading rooms that a bank could have around the world. These services could be sold to third-party users with the appropriate security services. Some experiments in a real grid environments will be presented to validate and verificate the utility as well as the performance of the proposed approach. [ABSTRACT FROM AUTHOR]

The creation of virtual humans capable of behaving and interacting realistically with each other requires the integration of interdisciplinary theories, methods and approaches. Although Intelligent Virtual Simulation has focused on realistic interactions of their inhabitants, it still reflects the necessity of a common framework capable of integrating all the technological advances developed separately. This paper combines some of the successful approaches carried out with the purpose of defining an openness framework that help making the development of Intelligent Virtual Agent based systems as easy as possible by the integration of these independent and different domains. The paper also presents a case study based on a virtual assistant helping a human and learning from him to use UML (Unified Modelling Language) for modelling different systems. [ABSTRACT FROM AUTHOR]

This paper presents an extension of the AMBLE model, an awareness model which manage load balancing by means of a multi-agent based architecture, with the aim to establish a cooperative load balancing model for collaborative grid environments. This model, named C-AMBLE (Cooperative Awareness Model for Balancing the Load in grid Environments) applies some theoretical principles of multi-agents systems, awareness models, and third party models, to promote an efficient autonomous cooperative task delivery in grid environments. This cooperative task management, implemented using web services, has been tested in a real and heterogeneous grid infrastructure with very successful results. This paper presents some of these outcomes while emphasizing on the performance speedup of the system using this model. [ABSTRACT FROM AUTHOR]

The justification for using mutihop clusters may be found in [1]. In the well known heuristic proposed in [2], the d-dominating set of clusterheads is first selected by using nodes identifiers and then clusters are formed. In this paper we generalise this algorithm in order to select nodes depending of a given criterion (as the the degree, density or energy of nodes). The first section of this paper simplifies and proves the correctness of our generalised algorithm to select clusterheads. The cluster formation process proposed in [2] is extensively studied in the second section and is proved to be false. [ABSTRACT FROM AUTHOR]

Recently, Doubletree, a cooperative algorithm for large-scale topology discovery at the IP level, was introduced. Compared to classic probing systems, Doubletree discovers almost as many nodes and links while strongly reducing the quantity of probes sent. This paper examines the problem of the nodes and links missed by Doubletree. In particular, this paper's first contribution is to carefully describe properties of the nodes and links that Doubletree fails to discover. We explain incomplete coverage as a consequence of the way Doubletree models the network: a tree-like structure of routes. But routes do not strictly form trees, due to load balancing and routing changes. This paper's second contribution is the Windowed Doubletree algorithm, which increases Doubletree's coverage up to 16% without increasing its load. Compared to classic Doubletree, Windowed Doubletree does not start probing at a fixed hop distance from each monitor, but randomly picks a value from a range of possible values. [ABSTRACT FROM AUTHOR]

This paper compares several approaches for dynamic allocation in geo-stationary networks based on DVB-RCS system. Each Satellite Terminal (ST) regularly sends requests to the Network Control Center (NCC) which in turn allocates resource to the users. Unfortunately, this delayed request-assignment makes the dynamic bandwidth allocation very difficult. Simple mechanisms such as a fixed allocation or requests based on the current size of the terminals' queue are compared to predictive methods based on control theory techniques which have been previously proposed. A lower bound is also derived by considering that the actual size of the buffer can be instantaneously known. It is shown that if the traffic is not really bursty, a fixed allocation which implies lighter signalling mechanisms leads to good results. In bursty traffic conditions, simple mechanisms for which the requests correspond to the actual size of the buffer may lead to the best performance results. [ABSTRACT FROM AUTHOR]

This paper investigates the use of cooperative communications in the context of IEEE 802.11b to combat radio signal degradation. The performance gain of both an existing cooperative protocol and the one proposed in the paper is discussed. It is quantitatively shown how much the two cooperative protocols increase throughput, lower delivery latency, and extend transmission span, when compared to the conventional IEEE 802.11b protocol. These features may help improve connectivity and network performance in ad hoc applications. [ABSTRACT FROM AUTHOR]

Two main steps on the way to more realistic simulations of mobile ad-hoc networks are the introduction of realistic mobility and sophisticated radio wave propagation models. Both have strong impact on the performance of mobile ad-hoc networks, e.g. the performance of routing protocols changes with these models. In this paper we introduce a framework which combines realistic mobility and radio wave propagation models. Our approach consists of a zone-based mobility generator and a high accuracy radio wave propagation model. For the mobility generation a wide variety of well understood random mobility models is combined with a graph based zone model, where each zone has its own mobility model. To achieve a realistic radio wave propagation model a ray tracing approach is used. The integration of these two techniques allows to create simulation setups that closely model reality. [ABSTRACT FROM AUTHOR]

Software product families have found broad adoption in the embedded systems industry. Product family thinking has been prevalent in this context for mechanics and hardware and adopting the same for software has been viewed as a logical approach. During recent years, however, the trends of convergence, end-to-end solutions, shortened innovation and R&D cycles and differentiation through software engineering capabilities have lead to a development where organizations are stretching the scope of their product families far beyond the initial design. Failing to adjust the product family approach, including the architectural and process dimensions when the business strategy is changing is leading to several challenging problems that can be viewed as symptoms of this approach. This paper discusses the key symptoms, the underlying causes for these symptoms as well as solutions for realigning the product family approach with the business strategy. [ABSTRACT FROM AUTHOR]

This paper presents a framework for deploying software components over a distributed system by using the notion of dynamics between components. It enables an application to be composed of one or more mobile components that can be deployed to different computers when the application is being executed. The key idea behind the framework is to provide components with deployment policies corresponding to gravitational and repulsive forces. The polices control the relocation relation between two components. As a result, a federation of distributed components can be moved and changed over a distributed system in a self-organizing manner. This paper also presents a prototype implementation of the approach and its applications. [ABSTRACT FROM AUTHOR]

In this paper we describe a self-organising and self-managing system for a Cooperative Service Provisioning (CSP) of media transport and processing services. The term cooperative is used since we assume that CSP providers as well as users offer resources to be utilised for media delivery and processing based on an Overlay Network principle. The core building block of the proposed system is a Distributed Hash Table extended with a CSP specific indexing principle and recursive search algorithm. The task of QoS constraint verification for a requested service is distributed between participating nodes. In this paper we describe CSP based on a Content Addressable Network (CAN) [1] DHT. The resulting system is evaluated based on a theoretical analysis as well as simulations. [ABSTRACT FROM AUTHOR]

This paper proposes a strategy to determine how much a given network can affect the QoS parameters of another, by interference. In order to achieve this, a measurement campaign was carried out in two stages: firstly with a single AP and later with two APs separated by a distance less than three meters, using the same channel. After the measurement, an analysis of the results and a set of inferences were made by using Bayesian Networks, whose inputs were the experimental data, i.e. QoS metrics such as: throughput, jitter, packet loss, PMOS and physical metrics like power and distance. [ABSTRACT FROM AUTHOR]

The rVsAll rollback-recovery protocol assures that consistency models, called session guarantees, are provided for mobile clients and unreliable servers. The protocol is optimized according to the required consistency model by taking into account properties of session guarantees and integrating their consistency management with known rollback-recovery techniques: message-logging and checkpointing. We have proved the correctness of rVsAll protocol in terms of safety and liveness properties. These properties assert that clients access object replicas maintained by servers according to the required session guarantee regardless of server's failures, and state that each access operation issued by clients will eventually be performed (in a finite time), even in the presence of server's failures. In this paper, we show that the proposed protocol is also optimal, in the sense that, the consistent global checkpoint taken in rVsAll protocol contains the minimal number of operations indispensable to fulfill the required session guarantees after server's failure and its recovery. The paper presents the proof of the optimality property of the proposed protocol. [ABSTRACT FROM AUTHOR]

Network-on-Chip is an alternative paradigm to improve communication bandwidth compared to bus-based communication, and its performance degrades if there is no effective flow control method., Heterogeneous networks with very slow processing elements (PEs) especially need a flow control mechanism at the transport layer to prevent too much packet injection. In this paper, a credit-based end-to-end flow control (CB-EEFC) is implemented to control the network latency at high traffic loads. Simulation in mesh networks shows improved performance in latency and 0.5% up to 3% saturated throughput decrease with the CB-EEFC method. RTL gate level simulation shows that a network interface using CB-EEFC brings about a 31.4% increase in complexity compared to a network interface without CB-EEFC. [ABSTRACT FROM AUTHOR]

One of TCP's key tasks is to react and avoid network congestion episodes which normally arise in packet switched networks. A wide literature is available concerning the behaviour of congestion control algorithms in many different scenarios and several congestion control algorithms have been proposed in order to improve performances in specific scenarios. In this paper we focus on the UMTS wireless scenario and we report a campaign of measurements that involved around 3000 flows and more than 40 hours of measurements using three different TCP stacks: TCP NewReno, which is the congestion control algorithm standardized by IETF, TCP BIC which is the default congestion control algorithm adopted by the Linux operating system, and TCP Westwood+ also available in the Linux kernel. The experimental evaluation has been carried out by accessing the public Internet using an UMTS card. Measurements of goodputs, RTTs over time, packet loss ratios, number of timeouts and Jain Fairness Indices are reported through cumulative distribution functions. Moreover, the efficiency of each TCP version in transferring files has been evaluated by varying the file size in the range from 50 KB up to 500 KB. The cumulative distribution functions reported in the paper show interesting results: 1) a single downlink flow is far from saturating the channel bandwidth; 2) considered TCP stacks provide similar results; 3) 90th (50th) percentile of the goodput of a single downlink flow is less or equal then 230 kbps (120 kbps) compared to a nominal 384 kbps UMTS downlink channel. [ABSTRACT FROM AUTHOR]

This paper focuses on parallel interactive applications ranging from scientific visualization, to virtual reality or computational steering. Interactivity makes them particular on three main aspects: they are endlessly iterative, use advanced I/O devices, and must perform under strong performance constraints (latency, refresh rate). In this paper, we propose an application description language based on a data flow and hierarchical component model to cope with the complexity of parallel interactive applications. It enables us to define highly generic components, enforcing the application maintainability and portability. An implementation on top of the FlowVR middleware is presented. [ABSTRACT FROM AUTHOR]

In this paper a high performance storage system for RDF documents is introduced. The system employs optimized index structures for RDF data and efficient RDF query evaluation. The index scheme consists of 3 types of indices. Triple index manages basic RDF triples by dividing original RDF graph into several sub-graphs. Path index manages frequent RDF path patterns for long path query performance enhancement. Context index is optional for context oriented RDF data and temporal RDF data. In this paper, we describe the organization of index structures, show the process of evaluating queries based on the index structures, and provide a performance comparison with exist RDF databases through several benchmark experiments. [ABSTRACT FROM AUTHOR]

To fulfill the application of wireless network in small area, this paper proposed a protocol for decentralized all-connected wireless network. This protocol is based on DS-CDMA with the ability of multi-user detection (MUD). And it has the characteristics of transmitting data in parallel, high network throughput and low communication error rate. In this paper, the process of the protocol is introduced, and an improved quasi-synchronous decorrelation multi-user detection algorithm is deduced in detail. And then, the protocol is simulated and the results are analyzed. [ABSTRACT FROM AUTHOR]

Multi-log2N networks architecture is attractive for constructing optical switches, and the related routing algorithms are critical for the operation and efficiency of such switches. Although several routing algorithms have been proposed for multi-log2N networks, a full performance comparison among them is not available by now. Thus, this paper is committed to such a comparison in terms of blocking probability, time complexity, hardware cost and load balancing capability. Notice that the load balance is important for reducing the peak power requirement of a switch, so we also propose in this paper two new routing algorithms for optical multi-log2N networks to achieve a better load balance. [ABSTRACT FROM AUTHOR]

The paper is devoted to application of formal concept analysis and collaborative design in shipbuilding. Sourcing and shoring strategies of a Norwegian multinational design company is illustrated by a concept lattice. [ABSTRACT FROM AUTHOR]

Nowadays, collaborative product development has become a strategic necessity to develop high quality products at low cost and with quick response time to market demand. Past decades have seen significant advances to collaborative product development. However, Enterprises are still confronted with some problems. Firstly, the research in strategic level of collaborative product development is lacking. There are no formal processes and models for collaborative product development. On the other hand, the full alignment between information system and collaborative business is still missing. The information system cannot adapt to the fast changed business. This paper aims to provide the strategy and reference business model for collaborative product development. And then, to support the implementation of strategy and model, a workflow and web service based engineering collaboration portal is developed. The workflow is used to model and execute the collaborative product development processes, and the web service is the implementing technology of the portal. The combination of workflow and web service can fit the gap between business and information system and achieve on-demand business. [ABSTRACT FROM AUTHOR]

This paper presents a document recommendation system based on clustering peer-to-peer networks. It's an unstructured P2P system. In this system each agent-peer can learn user's interest, then it helps user share and recommend documents with the other users. Since each peer in our P2P networks is a node, in order to cluster them, we import the concept of Group. Each group is composed of peers. The types of documents, which belong to a same group, are uniform. This paper presents how these peers help users to share and to recommend documents, and how they cluster into groups. Our experiment results show the advantages of the document recommendation system. [ABSTRACT FROM AUTHOR]

Collaborative team members usually come from diverse disciplines; their demands for knowledge are also different from each other. This paper is mainly concerned with how to capturing designers' knowledge demands in collaborative team. With the view from workflow, designers' knowledge demand is modeled from three aspects, members, roles, and tasks' requirements for knowledge. Based on the model of knowledge demand, some intelligent mining methods are proposed so that designers' knowledge demand could be derived automatically. With the knowledge demand model, a knowledge supply system could be developed to realize: knowledge within an appropriate domain could be delivered to the proper user among the collaborative team. [ABSTRACT FROM AUTHOR]

This paper is focused on differential conversion, which is a new approach to data transformation between different software systems. The strategy of differential conversion, which is built on a log of changes and identifier mapping, was introduced in CDVE 2006 in a purely theoretical paper entitled Data Exchange in CAD during Iterative Work with Heterogeneous Systems. A specific case study of differential conversion in use is elaborated in this text. It is about an intelligent bi-directional transformation between DWG and SVG. DWG is a proprietary CAD-format of the AutoCAD system, whereas SVG is an open, generic graphics format, based on XML. The implemented transformation allows usage of a model created in a CAD-system within a cooperative design intended for non-CAD users. It is useful not only for reading, but even for writing into the model and modifying it. Any changes made are returned back to the original model. The following case exemplifies the previously discussed strategy. For example, a project submitter, or another party in the review process, can use a normal, generic SVG editor for writing comments and proposals into the model. A solver can transform them back into the CAD-model, without other entities in the model being damaged. This case study describes differential export and import tools and takes note of the particular solutions of the log of changes and identifier mapping problems. It also describes the relationship to the original differential conversion proposal, discusses the particular implementation, and again generalizes into some design pattern for differential conversion implementation projects in the conclusion. [ABSTRACT FROM AUTHOR]

As the complexity of application system for enterprises, an important challenge is to dynamically schedule and integrate the heterogeneous and distributed services or activities to work cooperatively and efficiently. An effective technology to resolve the problem is grid service. A grid service built on both grid computing and web services technologies is an extended Web service. An application system for enterprises is a grid service composition that consists of a collection of grid services related by data and control flow. Therefore, there is a need for modeling and analyzing techniques and tools for reliable and effective grid service composition. The Petri net based method is an idea approach. In this paper, we use a colored dynamic timed Petri net (CDTPN) to model the grid service composition. The definition of CDTPN for grid service and an algorithm to construct a composite service are proposed. We give a definition of reachable service graph and an algorithm for constructing the reachable service graph of CDTPN. Finally, we discuss the correctness and effectiveness of the grid service composition by analyzing the reachable service graph. [ABSTRACT FROM AUTHOR]

Although security has been recognized as an increasingly important and critical issue for software system development, most security requirements are poorly specified: ambiguous, misleading, inconsistent among various parts, and lacking sufficient details. In this paper, a framework for specifying unambiguous, interoperable security requirements and detecting conflict and undesirable emergent properties in collaborative systems is presented. The framework includes a core ontology representing hierarchical security requirements , an ontology-based security requirement specification process, a set of security requirement refining rules, an algorithm for automatic security requirement refinement and an analysis algorithm to detect inconsistent security requirements. In this paper, the specification and refinement of security requirements are emphasized. Keywords: Software security, security specification, hierarchical security requirements, framework, collaborative systems, ontology, requirement refinement algorithms [ABSTRACT FROM AUTHOR]

I/O-driven integration applications, such as EAI, B2Bi, home gateways, and heterogeneous devices integration, need a trustworthy integration framework to process a large volume of I/O-driven transactions with high performance and reliability. This paper proposes an integration framework for trustworthy transactions. This framework employs a design pattern, so-called, the Worker-Linker pattern, that is used for performance stability. According to our experimental results, the pattern helps the integration framework to control the heavy load after the saturation point. Moreover, this framework supports a number of mechanisms for trustworthy integration transactions. In this paper, we describe the mechanisms. [ABSTRACT FROM AUTHOR]

A platform that simultaneously hosts multiple of cooperative services is proposed and called Autonomic Community Computing Infrastructure (ACCI). In autonomic and dynamic fashions, it formulates, composes, monitors and manages the services’ components. To publish the existence and functionalities of these services, a Peer-to-Peer Overlay Network is constructed and denoted by Rendezvous Overlay Network (RvON). In addition, RvON allows end-users to discover the service’s advertisement efficiently. Thus, this paper proposes an autonomic K-interleaving scheme that organizes RvON into RvON-Clusters. Each RvOn-Cluster is constructed over K physical hops and there is no two rendezvous nodes stored the same advertisement. As results, users accessing from different areas are able to efficiently discover service’s advertisement within a constant K physical hops Keywords: Autonomic Computing, Peer-to-Peer, Overlay Networks. [ABSTRACT FROM AUTHOR]

This paper presents an autonomic group location update (GLU) scheme for next-generation mobile networks. The GLU scheme takes account of the cooperative ability of the Mobile Terminals(MTs) in next-generation mobile networks, thus employs an autonomic group formation method to report location update in groups. A Leader Mobile Terminal(LMT) is elected out of all Group Members(GMs) to perform the location update and administration tasks for the whole group. Not only the bandwidth is saved for the efficiency of group operation, but also the whole system energy consumption of location update is significantly reduced in respect that communication range is much shorter in group than to base station. A leader rotation algorithm based on a variable called prestige is also exploited to make it fair. Both analysis and simulation show that the GLU scheme greatly saves energy for MTs and with our leader rotation algorithm, fairness can be also achieved. [ABSTRACT FROM AUTHOR]

In this paper, we consider the selfish routing problem in non- cooperative wireless mesh networks where the capacity can be improved by transmitting over multiple radios simultaneously using orthogonal channels. The problem is that there are some agents who are in charge of their transmissions and each of them is selfish to minimize its own transmission cost without considering the overall performance of the network. But the embarrassment in wireless mesh networks is that the selfish agents perhaps may cause interference for the non-cooperation. We think that the game theoretic tools are helpful for the selfish agents to make feasible choices. We yield a sufficient condition of the existence of pure strategy Nash equilibrium in our Strong Transmission Game and prove it in this paper. Some simulations reveal the feasibility of our game theoretic approach. [ABSTRACT FROM AUTHOR]

In this paper we present an autonomic rapid application composition scheme for ubiquitous systems. The main contribution of this paper is to provide a mode through which a mobile user can receive transparent service environment during his mobility period using the benefits of service composition paradigms. We propose a novel service selection matrix that enables the selection of the services similar to the ones that user was previously using. We observed that the user context is not the only key to improve the service selection rather some selection heuristics are also needed. Those search heuristics are provided through the degree of adaptive similarity. Our over all objective is to achieve high levels of service consistency and quality of service at higher layers. [ABSTRACT FROM AUTHOR]

Pervasive computing applications must be sufficiently autonomous to adapt their behaviour to changes in computing resources and user requirements. This capability is known as context-awareness. In some cases, context-aware applications must be implemented as autonomic systems which are capable of dynamically discovering and replacing context sources (sensors) at run-time. Unlike other types of application autonomy, this kind of dynamic reconfiguration has not been sufficiently investigated yet by the research community. However, application-level context models are becoming common, in order to ease programming of context-aware applications and support evolution by decoupling applications from context sources. We can leverage these context models to develop general (i.e., application-independent) solutions for dynamic, run-time discovery of context sources (i.e., context management). This paper presents a model and architecture for a reconfigurable context management system that supports interoperability by building on emerging standards for sensor description and classification. [ABSTRACT FROM AUTHOR]

The paper addresses the problem of using semantic annotations in XML documents for better querying XML data. We assume that the annotations refer to an ontology defined in OWL (Web Ontology Language). The intention is then to combine syntactic querying techniques on XML documents with OWL ontology reasoning to filter out semantically irrelevant answers. The solution presented in this paper is an extension of the declarative rule-based XML query and transformation language Xcerpt. The extension allows to interface an ontology reasoner from Xcerpt rules. This makes it possible to use Xcerpt to filter extracted XML data using ontological information. Additionally it allows to retrieve ontological information by sending semantic queries to a reasoner. The prototype implementation uses DIG (Description Logic interface) for communication with the OWL reasoner RacerPro where the ontology queries are answered. [ABSTRACT FROM AUTHOR]

Time management is a key feature needed in any query language for web and semistructured data. However, only recently this has been addressed by the Semantic Web community, through the study of temporal extensions to RDF (Resource Description Framework). In this paper we show that the ability of the RDF data model of handling unknown resources by means of blank nodes, naturally yields a rich framework for temporal reasoning in RDF. That is, even without knowing the interval of validity of some statements we can still entail useful knowledge from temporal RDF databases. To take advantage of this, we incorporate a class of temporal constraints over anonymous timestamps based on Allen's interval algebra. We show that testing entailment in temporal graphs with the constraints proposed reduces to closure computation and mapping discovery, that is, an extended form of the standard approach for testing entailment in non-temporal RDF graphs. [ABSTRACT FROM AUTHOR]

In previous papers we presented a type system for a substantial fragment of the Web query language Xcerpt. It is a descriptive type system: the typing of a program is an approximation of its semantics. The type system was expressed by means of rules, which could be seen as a comprehensible abstraction of a typing algorithm. That system treats some query terms in a rather simplistic way. As a result the approximations produced for them are rather imprecise. In this paper we provide an improved type system, producing more precise results. [ABSTRACT FROM AUTHOR]

The paper presents a framework for hybrid combination of rule languages with constraint languages including but not restricted to Description-Logic-based ontology languages. It shows how reasoning in a combined language can be done by interfacing reasoners of the component languages. A prototype system based on the presented principle integrates Datalog with OWL by interfacing XSB Prolog[2] with a DIG-compliant[1] DL reasoner (e.g. Racer[17] ). [ABSTRACT FROM AUTHOR]

In general, it requires lots of complicated and expensive processing functions to find the exact location of a mobile target. For example, Ubiquitous Robotic Companion (URC) system should be equipped with powerful resources or be given an aid from the external servers to find its location for itself. Sensor network that consists of inexpensive low-power sensors can provide an efficient solution to find the exact location of such a mobile target at a low price. In such applications, if all sensor nodes have to always wake up to find location of the mobile robot, we have to pay a lot of waste of resources such as battery power and channel utilization. In this paper, we propose a cheap and energy efficient location tracking method of a mobile robot by minimizing the number of sensor nodes participating in the task of target tracking. Keywords: Wireless sensor, target tracking, prediction, ubiquitous robot. [ABSTRACT FROM AUTHOR]

For the latest ten years, many authors have focused their investigations in wireless sensor networks. Different researching issues have been extensively developed: power consumption, MAC protocols, self-organizing network algorithms, data-aggregation schemes, routing protocols, QoS management, etc. Due to the constraints on data processing and power consumption, the use of artificial intelligence has been historically discarded. However, in some special scenarios the features of neural networks are appropriate to develop complex tasks such as path discovery. In this paper, we explore the performance of two very well known routing paradigms, directed diffusion and Energy-Aware Routing, and our routing algorithm, named SIR, which has the novelty of being based on the introduction of neural networks in every sensor node. Extensive simulations over our wireless sensor network simulator, OLIMPO, have been carried out to study the efficiency of the introduction of neural networks. A comparison of the results obtained with every routing protocol is analyzed. This paper attempts to encourage the use of artificial intelligence techniques in wireless sensor nodes. Keywords: Wireless sensor networks (WSN); Ad hoc networks, Quality of service (QoS); Artificial neural networks (ANN); Routing; Self-Organizing Map (SOM), ubiquitous computing. [ABSTRACT FROM AUTHOR]

GSM is the most popular standard for mobile phones in the world. In spite of the tremendous market growth, however, the GSM system has the fatal security problems in TMSI allocation protocol. These problems are right user authentication and location privacy. In this paper, we propose the secure TMSI allocation mechanism using the certification concept to solve these problems. The proposed mechanism provides partial anonymity, which has been rarely provided in the other approaches. Also we propose the modified mechanism to reduce TMSI allocation procedure without changing of the architecture of the original GSM system. [ABSTRACT FROM AUTHOR]

In this paper, we present an ongoing project on the concept of interaction among people via a mobile (city) application. The focus of our research lies on its usability and sociability, i.e., on all aspects that are related to community forming and development in a city context. In order to analyze them, we have developed a method that combines two techniques that are not common in usability studies: the association technique and the laddering method. We have called this combination the ‘connotation chain' technique. In this paper, we will first introduce this technique showing its advantages and disadvantages in a usability study. Then, we will present the results of applying this technique to our specific objective and, finally, we will discuss its implications for the further development of the interface of this application. Keywords: Mobile communication within a city context, Communities, Association technique, Laddering and User-centered design. [ABSTRACT FROM AUTHOR]

Several approaches for data interoperation identified by Karp have been implemented for biological databases. We extend Karp's approach for interoperation not only to protein databases but also to knowledge bases and other information sources. This paper outlines algebra for protein data source composition based on our existing work of Protein Ontology (PO). In this paper we consider the case of establishing correspondence between various protein data sources using semantic relationships over the conceptual framework of PO. Here we provide specific set of relationships over PO framework to cover data semantics for integrating data information from diverse protein data sources. These relationships help in defining semantic query algebra for PO to efficiently reason and query the instance store. [ABSTRACT FROM AUTHOR]

This paper proposes a method for query approximation in Geographical Information Systems. In our approach, queries are expressed by the Geographical Pictorial Query Language (GeoPQL), and query approximation is performed using WordNet, a lexical database for the English language available on the Internet. Due to the focus on geographical context, we address WordNetpartitiontaxonomies. If a concept contained in a query has no match in the database, the query is approximated using the immediate superconcepts and subconcepts in the WordNet taxonomy, and their related degrees of similarity. Semantic similarity is evaluated using the information content approach, which shows a higher correlation with human judgment than the traditional similarity measures. [ABSTRACT FROM AUTHOR]

Starting from the era of stove-piped Geographical Information Systems up to interesting mash-ups involving Internet based mapping services, the approaches of handling Geographical Information (GI) have changed significantly. This paper briefly concentrates up on the distinctive features and current implementations of Spatial Data Access Patterns. Considering the information requirements of the users in Emergency Operations Center, this paper identifies the issues and challenges in handling GI in dynamically changing environments. Two new patterns based on appropriate integration of Semantics and Grid technology are introduced, that may satisfy the identified requirements. Necessary alterations in current practices for handling GI is discussed with detail considerations for realization of these patterns on open environments. [ABSTRACT FROM AUTHOR]

This paper describes, for the case of Enterprise Java Bean components and JBoss application server, how replication for availability can be supported to tolerate application server/transaction manager failures. Replicating the state associated with the progression of a transaction (i.e., which phase of two-phase commit is enacted and the transactional resources involved) provides an opportunity to continue a transaction using a backup transaction manager if the transaction manager of the primary fails. Existing application servers do not support this functionality. The paper discusses the technical issues involved and shows how a solution can be engineered. Keywords: Availability, application servers, components, Enterprise Java Beans, fault tolerance, middleware, replication, transactions. [ABSTRACT FROM AUTHOR]