bluuebunny/crossref_metadata_2025 huggingface dataset:
A Simplified Method for Implementing Run‐Time Polymorphism in Fortran95
Authors: Decyk Viktor K. , Norton Charles D.
Published: January 2015

This paper discusses a simplified technique for software emulation of inheritance and run‐time polymorphism in Fortran95. This technique involves retaining the same type throughout an inheritance hierarchy, so that only functions which are modified in a derived class need to be implemented.
Framework for Bringing Data Streams to the Grid
Authors: Plale Beth
Published: January 2015

Data streams are a prevalent and growing source of timely data, particularly in the scientific domain. Just as it is common today to read starting conditions such as initial weather conditions, for a scientific simulation from a file, it should be equally as easy to draw starting conditions on‐demand from live data streams. But efforts to date to bring streaming data to the grid have lacked generality. In this article we introduce a new model for bringing existing data streams systems onto the grid. The model is predicated on the ability to identify stream systems that meet the criteria of being a "data resource". We establish the criteria in this article, and define a grid service architecture for a data streams resource that leverages standardization efforts in the Global Grid Forum. We discuss key research issues in realizing the data streams model. We are currently developing a prototype of this architecture using our dQUOB system.
A Low‐Cost Rescheduling Policy for Efficient Mapping of Workflows on Grid Systems
Authors: Sakellariou Rizos , Zhao Henan
Published: January 2015

Workflow management is emerging as an important service in Grid computing. A simple model that can be used for the representation of certain workflows is a directed acyclic graph. Although many heuristics have been proposed to schedule such graphs on heterogeneous environments, most of them assume accurate prediction of computation and communication costs. This limits their direct applicability to a dynamically changing environment, such as the Grid. In this environment, an initial schedule may be built based on estimates, but run‐time rescheduling may be needed to improve application performance. This paper presents a low‐cost rescheduling policy, which considers rescheduling at a few, carefully selected points during the execution. This policy achieves performance results, which are comparable with those achieved by a policy that dynamically attempts to reschedule before the execution of every task.
JIST: Just‐In‐Time Scheduling Translation for Parallel Processors
Authors: Agosta Giovanni , Reghizzi Stefano Crespi , Falauto Gerlando , Sykora Martino
Published: January 2015

The application fields of bytecode virtual machines and VLIW processors overlap in the area of embedded and mobile systems, where the two technologies offer different benefits, namely high code portability, low power consumption and reduced hardware cost. Dynamic compilation makes it possible to bridge the gap between the two technologies, but special attention must be paid to software instruction scheduling, a must for the VLIW architectures. We have implemented JIST, a Virtual Machine and JIT compiler for Java Bytecode targeted to a VLIW processor. We show the impact of various optimizations on the performance of code compiled with JIST through the experimental study on a set of benchmark programs. We report significant speedups, and increments in the number of instructions issued per cycle up to 50% with respect to the non‐scheduling version of the JITcompiler. Further optimizations are discussed.
Research in Mobile Database Query Optimization and Processing
Authors: Waluyo Agustinus Borgy , Srinivasan Bala , Taniar David
Published: January 2015

The emergence of mobile computing provides the ability to access information at any time and place. However, as mobile computing environments have inherent factors like power, storage, asymmetric communication cost, and bandwidth limitations, efficient query processing and minimum query response time are definitely of great interest. This survey groups a variety of query optimization and processing mechanisms in mobile databases into two main categories, namely: (i) query processing strategy, and (ii) caching management strategy. Query processing includes both pull and push operations (broadcast mechanisms). We further classify push operation into on‐demand broadcast and periodic broadcast. Push operation (on‐demand broadcast) relates to designing techniques that enable the server to accommodate multiple requests so that the request can be processed efficiently. Push operation (periodic broadcast) corresponds to data dissemination strategies. In this scheme, several techniques to improve the query performance by broadcasting data to a population of mobile users are described. A caching management strategy defines a number of methods for maintaining cached data items in clients′ local storage. This strategy considers critical caching issues such as caching granularity, caching coherence strategy and caching replacement policy. Finally, this survey concludes with several open issues relating to mobile query optimization and processing strategy.
On the Design of Energy‐Efficient Location Tracking Mechanism in Location‐Aware Computing
Authors: Song MoonBae , Kang Sang-Won , Park KwangJin
Published: January 2015

The battery, in contrast to other hardware, is not governed by Moore′s Law. In location‐aware computing, power is a very limited resource. As a consequence, recently, a number of promising techniques in various layers have been proposed to reduce the energy consumption. The paper considers the problem of minimizing the energy used to track the location of mobile user over a wireless link in mobile computing. Energy‐efficient location update protocol can be done by reducing the number of location update messages as possible and switching off as long as possible. This can be achieved by the concept of mobility‐awareness we propose. For this purpose, this paper proposes a novel mobility model, called state‐based mobility model (SMM) to provide more generalized framework for both describing the mobility and updating location information of complexly moving objects. We also introduce the state‐based location update protocol (SLUP) based on this mobility model. An extensive experiment on various synthetic datasets shows that the proposed method improves the energy efficiency by 2 ∼ 3 times with the additional 10% of imprecision cost.
An Improved Itinerary Recording Protocol for Securing Distributed Architectures Based on Mobile Agents
Authors: Allée Guillaume , Pierre Samuel , Glitho Roch H. , El Rhazi Abdelmorhit
Published: January 2015

This paper proposes an improved itinerary recording protocol for securing distributed architectures based on mobile agents. The behavior of each of the cooperating agents is described, as well as the decision process establishing the identities of offenders when an attack is detected. Our protocol is tested on a set of potential attacks and the results confirm our assumption regarding offender designations and moments of detection. More precisely, the performance evaluation shows that our protocol detects the attack where there is collaboration between a platform on the cooperating agents′ itinerary and another on the mobile agent′s itinerary. As a result, this protocol constitutes a suitable option for electronic commerce applications where security concerns prevail over cost factors.
Multi‐Resolution Information Transmission in Mobile Environments
Authors: Va Leong Hong , Si Antonio
Published: January 2015

Mobile environments are characterized by low communication bandwidth and frequent disconnection. Conventional information retrieval and visualization mechanisms thus pose a serious challenge to mobile clients. There is a need for these clients to quickly perceive an overall picture of the information available to them, so as to enable them to discontinue the transmission of information units that are unlikely useful to them. We had proposed a multi-resolution transmission mechanism for web documents. In particular, various organizational units of a document are transmitted to a mobile client in an order according to their information content, thereby allowing the client to terminate the transmission of a useless document at an earlier moment. In this paper, we generalize the multi-resolution transmission model for a document, and then extend that model into the multi‐resolution transmission framework to cater for not only units within a document, but also for a collection of documents. We refer to the multi‐resolution transmission mechanism for a particular document as intra-document multi-resolution transmission mechanism and the extension to a document cluster as inter-document multi-resolution transmission mechanism. With the integrated multi‐resolution transmission framework, a mobile client can examine the important portions of the document cluster for an early grasp of the information therein, with the most important contents for each of those documents more readily available as well.
Parallel Framework for Cooperative Processes
Authors: Craus Mitică , Rudeanu Laurenţiu
Published: January 2015

This paper describes the work of an object oriented framework designed to be used in the parallelization of a set of related algorithms. The idea behind the system we are describing is to have a re‐usable framework for running several sequential algorithms in a parallel environment. The algorithms that the framework can be used with have several things in common: they have to run in cycles and the work should be possible to be split between several "processing units". The parallel framework uses the message‐passing communication paradigm and is organized as a master‐slave system. Two applications are presented: an Ant Colony Optimization (ACO) parallel algorithm for the Travelling Salesman Problem (TSP) and an Image Processing (IP) parallel algorithm for the Symmetrical Neighborhood Filter (SNF). The implementations of these applications by means of the parallel framework prove to have good performances: approximatively linear speedup and low communication cost.
Automating Security Configuration for the Grid
Authors: Clayton Brian C. , Quillinan Thomas B. , Foley Simon N.
Published: January 2015

Administration of Grid resources is a time consuming and often tedious job. Most administrative requests are predictable, and in general, handling them requires knowledge of the local resources and the requester. In this paper we discuss a system to provide automated support for administrative requests, such as resource reservation and user account management. We propose using trust metrics to help judge the merits and suitability of each request. We outline how these metrics can be implemented using trust management techniques into a practical system we call GridAdmin.
When Location‐Based Services Meet Databases
Authors: Lee Dik Lun , Zhu Manli , Hu Haibo
Published: January 2015

As location‐based services (LBSs) grow to support a larger and larger user community and to provide more and more intelligent services, they must face a few fundamental challenges, including the ability to not only accept coordinates as location data but also manipulate high‐level semantics of the physical environment. They must also handle a large amount of location updates and client requests and be able to scale up as their coverage increases. This paper describes some of our research in location modeling and updates and techniques for enhancing system performance by caching and batch processing. It can be observed that the challenges facing LBSs share a lot of similarity with traditional database research (i.e., data modeling, indexing, caching, and query optimization) but the fact that LBSs are built into the physical space and the opportunity to exploit spatial locality in system design shed new light on LBS research.
Efficiency of JADE Agent Platform
Authors: Chmiel Krzysztof , Gawinecki Maciej , Kaczmarek Pawel , Szymczak Michal , Paprzycki Marcin
Published: January 2015

Agent oriented programming is often claimed to become the next breakthrough in development and implementation of large‐scale complex software systems. At the same time it is rather difficult to find successful applications of agent technology, in particular when large‐scale systems are considered. The aim of this paper is to investigate if one of the possible limits could be the scalability of existing agent environments. For this purpose we have selected JADE agent platform and investigated its performance in a number of test‐scenarios. Results of our experiments are presented and discussed.
Styx Grid Services: Lightweight Middleware for Efficient Scientific Workflows
Authors: Blower J.D. , Harrison A.B. , Haines K.
Published: January 2015

The service‐oriented approach to performing distributed scientific research is potentially very powerful but is not yet widely used in many scientific fields. This is partly due to the technical difficulties involved in creating services and workflows and the inefficiency of many workflow systems with regard to handling large datasets. We present the Styx Grid Service, a simple system that wraps command‐line programs and allows them to be run over the Internet exactly as if they were local programs. Styx Grid Services are very easy to create and use and can be composed into powerful workflows with simple shell scripts or more sophisticated graphical tools. An important feature of the system is that data can be streamed directly from service to service, significantly increasing the efficiency of workflows that use large data volumes. The status and progress of Styx Grid Services can be monitored asynchronously using a mechanism that places very few demands on firewalls. We show how Styx Grid Services can interoperate with with Web Services and WS‐Resources using suitable adapters.
Reusable Object‐Oriented Solutions for Numerical Simulation of PDEs in a High Performance Environment
Authors: Lani Andrea , Quintino Tiago , Kimpe Dries , Deconinck Herman , Vandewalle Stefan , Poedts Stefaan
Published: January 2015

Object‐oriented platforms developed for the numerical solution of PDEs must combine flexibility and reusability, in order to ease the integration of new functionalities and algorithms. While designing similar frameworks, a built‐in support for high performance should be provided and enforced transparently, especially in parallel simulations. The paper presents solutions developed to effectively tackle these and other more specific problems (data handling and storage, implementation of physical models and numerical methods) that have arisen in the development of COOLFluiD, an environment for PDE solvers. Particular attention is devoted to describe a data storage facility, highly suitable for both serial and parallel computing, and to discuss the application of two design patterns, Perspective and Method‐Command‐Strategy, that support extensibility and run‐time flexibility in the implementation of physical models and generic numerical algorithms respectively.
Bluetooth: Opening a Blue Sky for Healthcare
Authors: Wang X. H. , Iqbal M.
Published: January 2015

Over the last few years, there has been a blossoming of developing mobile healthcare programs. Bluetooth technology, which has the advantages of being low‐power and inexpensive, whilst being able to transfer moderate amounts of data over a versatile, robust and secure radio link, has been widely applied in mobile healthcare as a replacement for cables. This paper discussed the applications of Bluetooth technology in healthcare. It started with the brief description of the history of Bluetooth technology, its technical characteristics, and the latest developments. Then the applications of Bluetooth technology in healthcare sector were reviewed. The applications are based on two basic types of links of Bluetooth technology: point‐to‐point link and point‐to‐multipoint link. The special requirements from healthcare and the challenges of successful application of Bluetooth in healthcare will be discussed. At last the future development of Bluetooth technology and its impacts on healthcare were envisioned.
Impact of Radio Randomness on Performances of Lattice Wireless Sensors Networks Based on Event‐Reliability Concept
Authors: Yang T. , De Marco G. , Ikeda M. , Barolli L.
Published: January 2015

The problem of congestion control in wireless sensor networks is very important, especially in very dense networks. In this work, we use a simple packet repetition scheme as congestion and event‐reliability control. In contrast to other works on the performance study of such a scheme, we use a random radio pathloss model. We are motivated by this choice, because the radio model usually used in most of studies on wireless sensor networks is deterministic. However, this is not the case encountered in real hardware. Here, we show that the analysis of such a scheme by simulation is not trivial when more realistic radio models are used. We emphasise this problem by comparing the differences of simulation results with respect to the non random pathloss case, also known as isotropic model. As expected, simulations confirm that radio irregularities can not be neglected and the efficiency of event‐reliability based congestion control should be properly revised. This aspect calls for new mechanisms of coordination among sensor nodes.
Communication Analysis of Distributed Programs
Authors: Simmons Sharon , Edwards Dennis , Kearns Phil
Published: January 2015

Capturing and examining the causal and concurrent relationships of a distributed system is essential to a wide range of distributed systems applications. Many approaches to gathering this information rely on trace files of executions. The information obtained through tracing is limited to those executions observed. We present a methodology that analyzes the source code of the distributed system. Our analysis considers each process′s source code and produces a single comprehensive graph of the system′s possible behaviors. The graph, termed the partial order graph (POG), uniquely represents each possible partial order of the system. Causal and concurrent relationships can be extracted relative either to a particular partial order, which is synonymous to a single execution, or to a collection of partial orders. The graph provides a means of reasoning about the system in terms of relationships that will definitely occur, may possible occur, and will never occur. Distributed assert statements provide a means to monitor distributed system executions. By constructing the POG prior to system execution, the causality information provided by the POG enables run‐time evaluation of the assert statement without relying on traces or addition messages.
A Stochastic Model for Workflow QoS Evaluation
Authors: Xia Yunni , Wang H.P. , Huang Y. , Yuan L.
Published: January 2015

Quality (QoS) prediction is one of the most important research topics of workflow. In this paper, we propose a stochastic model to evaluate QoS (make‐span, reliability and cost) of workflow systems based on QWF‐net, which extends traditional WF‐net by associating tasks with firing‐rate, failure‐rate and cost‐coefficient. Through a case study, we show that our framework is capable of modeling real‐world workflow‐based application. Also, Monte‐carlo simulation in the case study indicates our analytical methods are consistent with simulation. We also present a sensitivity analysis technique to identify QoS bottleneck.The paper concludes with a comparison between our approach and related work.
An Agent Based Intrusion Detection Model for Mobile Ad Hoc Networks
Authors: Reshmi B. M. , Manvi S. S. , Bhagyavati
Published: January 2015

Intrusion detection has over the last few years, assumed paramount importance within the broad realm of network security, more so in case of wireless mobile ad hoc networks. The inherently vulnerable characteristics of wireless mobile ad hoc networks make them susceptible to attacks in‐spite of some security measures, and it may be too late before any counter action can take effect. As such, there is a need to complement traditional security mechanisms with efficient intrusion detection and response systems. This paper proposes an agent‐based model to address the aspect of intrusion detection in cluster based mobile wireless ad hoc network environment. The model comprises of a set of static and mobile agents, which are used to detect intrusions, respond to intrusions, and distribute selected and aggregated intrusion information to all other nodes in the network in an intelligent manner. The model is simulated to test its operation effectiveness by considering the performance parameters such as, detection rate, false positives, agent overheads, and intrusion information distribution time. Agent based approach facilitates flexible and adaptable security services. Also, it supports component based software engineering components such as maintainability, reachability, reusability, adaptability, flexibility, and customization.
A Novel Data Replication and Management Protocol for Mobile Computing Systems
Authors: Abawajy J. H. , Deris M. Mat , Omar M.
Published: January 2015

Mobile computing has enabled users to seamlessly access databases even when they are on the move. Mobile computing environments require data management approaches that are able to provide complete and highly available access to shared data at any time from any where. In this paper, we propose a novel replicated data protocol for achieving such goal. The proposed scheme replicates data synchronously over stationary sites based on three dimensional grid structure while objects in mobile sites are asynchronously replicated based on commonly visited sites for each user. This combination allows the proposed protocol to operate with less than full connectivity, to easily adapt to changes in group membership and not require all sites to agree to update data objects at any given time, thus giving the technique flexibility in mobile environments. The proposed replication technique is compared with a baseline replication technique and shown to exhibit high availability, fault tolerance and minimal access times of the data and services, which are very important in an environment with low‐quality communication links.
High Performance Publish/Subscribe Middleware for Mobile Wireless Networks
Authors: Farooq Umar , Majumdar Shikharesh , Parsons Eric W.
Published: January 2015

Decoupling, flexible, scalable and asynchronous nature of publish/subscribe paradigms makes them a good choice for mobile wireless networks. However, our research shows that current implementations of publish/subscribe systems as well as the traditional solutions for extending publish/subscribe systems to the mobile domain do not perform well in highly mobile and unreliable wireless settings. We present semi‐durable subscriptions, a technique that we have developed to overcome the challenges and the performance concerns publish/subscribe systems face in mobile wireless settings. We discuss the architecture of semi‐durable subscriptions and study in detail the effect of various mobility parameters on the performance of semi‐durable subscriptions to demonstrate their efficacy in mobile wireless settings. We also discuss system parameters for semi‐durable subscriptions and with the help of experimental results demonstrate how these parameters can be controlled to configure a system according to a set of desired characteristics.
Cooperative Caching in Mobile Ad Hoc Networks Based on Data Utility
Authors: Chand Narottam , Joshi R. C. , Misra Manoj
Published: January 2015

Cooperative caching, which allows sharing and coordination of cached data among clients, is a potential technique to improve the data access performance and availability in mobile ad hoc networks. However, variable data sizes, frequent data updates, limited client resources, insufficient wireless bandwidth and client′s mobility make cache management a challenge. In this paper, we propose a utility based cache replacement policy, least utility value (LUV), to improve the data availability and reduce the local cache miss ratio. LUV considers several factors that affect cache performance, namely access probability, distance between the requester and data source/cache, coherency and data size. A cooperative cache management strategy, Zone Cooperative (ZC), is developed that employs LUV as replacement policy. In ZC one‐hop neighbors of a client form a cooperation zone since the cost for communication with them is low both in terms of energy consumption and message exchange. Simulation experiments have been conducted to evaluate the performance of LUV based ZC caching strategy. The simulation results show that, LUV replacement policy substantially outperforms the LRU policy.
Dynamic Service Selection in Workflows Using Performance Data
Authors: Walker David W. , Huang Lican , Rana Omer F. , Huang Yan
Published: January 2015

An approach to dynamic workflow management and optimisation using near‐realtime performance data is presented. Strategies are discussed for choosing an optimal service (based on user‐specified criteria) from several semantically equivalent Web services. Such an approach may involve finding "similar" services, by first pruning the set of discovered services based on service metadata, and subsequently selecting an optimal service based on performance data. The current implementation of the prototype workflow framework is described, and demonstrated with a simple workflow. Performance results are presented that show the performance benefits of dynamic service selection. A statistical analysis based on the first order statistic is used to investigate the likely improvement in service response time arising from dynamic service selection.
Parallel MOPEX: Computing Mosaics of Large‐Area Spitzer Surveys on a Cluster Computer
Authors: Jacob Joseph C. , Eisenhardt Peter , Makovoz David
Published: January 2015

The Spitzer Science Center′s MOPEX software is a part of the Spitzer Space Telescope′s operational pipeline that enables detection of cosmic ray collisions with the detector array, masking of the corrupted pixels due to these collisions, subsequent mosaicking of image fields, and extraction of point sources to create catalogs of celestial objects. This paper reports on our experiences in parallelizing the parts of MOPEX related to cosmic ray rejection and mosaicking on a 1,024‐processor cluster computer at NASA′s Jet Propulsion Laboratory. The architecture and performance of the new Parallel MOPEX software are described. This work was done in order to rapidly mosaic the IRAC shallow survey data, covering a region of the sky observed with one of Spitzer′s infrared instruments for the study of galaxy clusters, large‐scale structure, and brown dwarfs.
GRIDCC: A Real‐Time Grid Workflow System with QoS
Authors: McGough A. Stephen , Akram Asif , Guo Li , Krznaric Marko , Dickens Luke , Colling David , Martyniak Janusz , Powell Roger , Kyberd Paul , Huang Chenxi , Kotsokalis Constantinos , Tsanakas Panayiotis
Published: January 2015

The over‐arching aim of Grid computing is to move computational resources from individual institutions where they can only be used for in‐house work, to a more open vision of vast online ubiquitous `virtual computational′ resources which support individuals and collaborative projects. A major step towards realizing this vision is the provision of instrumentation – such as telescopes, accelerators or electrical power stations – as Grid resources, and the tools to manage these resources online. The GRIDCC project attempts to satisfy these requirements by providing the following four co‐dependent components; a flexible wrapper for publishing instruments as Grid resources; workflow support for the orchestration of multiple Grid resources in a timely manner; the machinery to make reservation agreements on Grid resources; and the facility to satisfy quality of service (QoS) requirements on elements within workflows. In this paper we detail the set of services developed as part of the GRIDCC project to provide the last three of these components. We provide a detailed architecture for these services along with experimental results from load testing experiments. These services are currently deployed as a test‐bed at a number of institutions across Europe, and are poised to provide a ′virtual lab′ to production level applications.
Specification and Runtime Workflow Support in the ASKALON Grid Environment
Authors: Prodan Radu
Published: January 2015

We describe techniques to support the runtime execution of scientific workflows in the ASKALON Grid environment. We present a formal model and three middleware services that support in combination the effective execution in heterogeneous and dynamic Grid environments: performance prediction, scheduling, and enactment engine. We validate our techniques with concrete experimental results for two real‐world applications executed in the Austrian Grid environment.
Presence in the IP Multimedia Subsystem
Authors: Lin Ling , Liotta Antonio
Published: January 2015

With an ever increasing penetration of Internet Protocol (IP) technologies, the wireless industry is evolving the mobile core network towards all‐IP network. The IP Multimedia Subsystem (IMS) is a standardised Next Generation Network (NGN) architectural framework defined by the 3rd Generation Partnership Project (3GPP) to bridge the gap between circuit‐switched and packet‐switched networks and consolidate both sides into on single all‐IP network for all services. In this paper, we provide an insight into the limitation of the presence service, one of the fundamental building blocks of the IMS. Our prototype‐based study is unique of its kind and helps identifying the factors which limit the scalability of the current version of the presence service (3GPP TS 23.141 version 7.2.0 Release 7 [1]), which will in turn dramatically limit the performance of advanced IMS services. We argue that the client‐server paradigm behind the current IMS architecture does not suite the requirements of the IMS system, which defies the very purpose of its introduction. We finally elaborate on possible avenues for addressing this problem.
VLAM‐G: Interactive Data Driven Workflow Engine for Grid‐Enabled Resources
Authors: Korkhov Vladimir , Vasyunin Dmitry , Wibisono Adianto , Belloum Adam S.Z. , Inda Márcia A. , Roos Marco , Breit Timo M. , Hertzberger L.O.
Published: January 2015

Grid brings the power of many computers to scientists. However, the development of Grid‐enabled applications requires knowledge about Grid infrastructure and low‐level API to Grid services. In turn, workflow management systems provide a high‐level environment for rapid prototyping of experimental computing systems. Coupling Grid and workflow paradigms is important for the scientific community: it makes the power of the Grid easily available to the end user. The paradigm of data driven workflow execution is one of the ways to enable distributed workflow on the Grid. The work presented in this paper is carried out in the context of the Virtual Laboratory for e‐Science project. We present the VLAM‐G workflow management system and its core component: the Run‐Time System (RTS). The RTS is a dataflow driven workflow engine which utilizes Grid resources, hiding the complexity of the Grid from a scientist. Special attention is paid to the concept of dataflow and direct data streaming between distributed workflow components. We present the architecture and components of the RTS, describe the features of VLAM‐G workflow execution, and evaluate the system by performance measurements and a real life use case.
Taxonomy and Analysis of IP Micro‐Mobility Protocols in Single and Simultaneous Movements Scenarios
Authors: De Marco G. , Barolli L. , Loreto Salvatore
Published: January 2015

The micro‐mobility is an important aspect in mobile communications, where the applications are anywhere and used anytime. One of the problems of micro‐mobility is the hand‐off latency. In this paper, we analyse two solutions for IP micro‐mobility by means of a general taxonomy. The first one is based on the Stream Control Transmission Protocol (SCTP), which allows the dynamic address configuration of an association. The second one is based on the Session Initiation Protocol (SIP), which is the most popular protocol for multimedia communications over IP networks. We show that for the SCTP solution, there is room for further optimisations of the hand‐off latency by adding slight changes to the protocol. However, as full end‐to‐end solution, SCTP is not able to handle simultaneous movement of hosts, whose probability in general cannot be neglected. On the other hand, the SIP can handle both single and simultaneous movements cases, although the hand‐off latency can increase with respect to the SCTP solution. We show that for a correct and fast hand‐off, the SIP server should be statefull.
Scientific Programming in Fortran
Authors: Van Snyder W.
Published: January 2015

The Fortran programming language was designed by John Backus and his colleagues at IBM to reduce the cost of programming scientific applications. IBM delivered the first compiler for its model 704 in 1957. IBM′s competitors soon offered incompatible versions. ANSI (ASA at the time) developed a standard, largely based on IBM′s Fortran IV in 1966. Revisions of the standard were produced in 1977, 1990, 1995 and 2003. Development of a revision, scheduled for 2008, is under way. Unlike most other programming languages, Fortran is periodically revised to keep pace with developments in language and processor design, while revisions largely preserve compatibility with previous versions. Throughout, the focus on scientific programming, and especially on efficient generated programs, has been maintained.
Secure Authentication in Heterogeneous Wireless Networks
Authors: Durresi Arjan , Durresi Mimoza , Barolli Leonard
Published: January 2015

The convergence of cellular and IP technologies has pushed the integration of 3G and WLAN networks to the forefront. Gaining secure access to 3G services from 802.11 WLANs is a primary challenge for this new integrated wireless technology. Successful execution of 3G security algorithms can be limited to a specified area by encrypting a user′s authentication challenge with spatial data defining his visited WLAN. With limited capacity to determine a user′s location only to within a current cell and restrictions on accessing users′ location due to privacy, 3G operators must rely on spatial data sent from visited WLANs to implement spatial authentication control. A potential risk is presented to 3G operators since no prior relationship or trust may exist with a WLAN owner. Algorithms to quantify the trust between all parties of 3G‐WLAN integrated networks are presented to further secure user authentication. Ad‐hoc serving networks and the trust relationships established between mobile users are explored to define stronger algorithms for 3G – WLAN user authentication.
Networked Biomedical System for Ubiquitous Health Monitoring
Authors: Durresi Arjan , Durresi Mimoza , Merkoci Arben , Barolli Leonard
Published: January 2015

We propose a distributed system that enables global and ubiquitous health monitoring of patients. The biomedical data will be collected by wearable health diagnostic devices, which will include various types of sensors and will be transmitted towards the corresponding Health Monitoring Centers. The permanent medical data of patients will be kept in the corresponding Home Data Bases, while the measured biomedical data will be sent to the Visitor Health Monitor Center and Visitor Data Base that serves the area of present location of the patient. By combining the measured biomedical data and the permanent medical data, Health Medical Centers will be able to coordinate the needed actions and help the local medical teams to make quickly the best decisions that could be crucial for the patient health, and that can reduce the cost of health service.
Inter-Operating Grids Through Delegated MatchMaking
Authors: Iosup Alexandru , Tannenbaum Todd , Farrellee Matthew , Epema Dick , Livny Miron
Published: January 2015

The grid vision of a single computing utility has yet to materialize: while many grids with thousands of processors each exist, most work in isolation. An important obstacle for the effective and efficient inter-operation of grids is the problem of resource selection. In this paper we propose a solution to this problem that combines the hierarchical and decentralized approaches for interconnecting grids. In our solution, a hierarchy of grid sites is augmented with peer-to-peer connections between sites under the same administrative control. To operate this architecture, we employ the key concept of delegated matchmaking, which temporarily binds resources from remote sites to the local environment. With trace-based simulations we evaluate our solution under various infrastructural and load conditions, and we show that it outperforms other approaches to inter-operating grids. Specifically, we show that delegated matchmaking achieves up to 60% more goodput and completes 26% more jobs than its best alternative.
EHeBby: An Evocative Humorist Chat‐Bot
Authors: Pilato Giovanni , Augello Agnese , Vassallo Giorgio , Gaglio Salvatore
Published: January 2015

A conversational agent, capable to have a "sense of humor" is presented. The agent can both generate humorous sentences and recognize humoristic expressions introduced by the user during the dialogue. EHeBby is an entertainment oriented conversational agent implemented using the ALICE framework embedded into an Yahoo! Messenger client. It is characterized by two areas: a rational, rule‐based area and an evocative area. The first one is based on well founded techniques of computational humor and a standard AIML KB. The second one is based on a conceptual space, automatically induced by a corpus of funny documents, where KB items and user sentences are mapped. This area emulates an associative/evocative behavior of the conversational agent, making her more attractive. EHeBby includes also an avatar that changes the face expression according to humoristic content of the dialogue.
Inferring Neuronal Network Connectivity from Spike Data: A Temporal Data Mining Approach
Authors: Patnaik Debprakash , Sastry P.S. , Unnikrishnan K.P.
Published: January 2015

Understanding the functioning of a neural system in terms of its underlying circuitry is an important problem in neuroscience. Recent developments in electrophysiology and imaging allow one to simultaneously record activities of hundreds of neurons. Inferring the underlying neuronal connectivity patterns from such multi-neuronal spike train data streams is a challenging statistical and computational problem. This task involves finding significant temporal patterns from vast amounts of symbolic time series data. In this paper we show that the frequent episode mining methods from the field of temporal data mining can be very useful in this context. In the frequent episode discovery framework, the data is viewed as a sequence of events, each of which is characterized by an event type and its time of occurrence and episodes are certain types of temporal patterns in such data. Here we show that, using the set of discovered frequent episodes from multi-neuronal data, one can infer different types of connectivity patterns in the neural system that generated it. For this purpose, we introduce the notion of mining for frequent episodes under certain temporal constraints; the structure of these temporal constraints is motivated by the application. We present algorithms for discovering serial and parallel episodes under these temporal constraints. Through extensive simulation studies we demonstrate that these methods are useful for unearthing patterns of neuronal network connectivity.
WIT: A Wireless Integrated Traffic Model
Authors: Doci Arta , Xhafa Fatos
Published: January 2015

Simulation is a common approach for designing ad hoc network applications, due to the slow deployment of these networks. The main building blocks of ad hoc network applications are the routing protocols, mobility, and traffic models. Several studies, which use synthetic models, show that mobility and traffic have a significant effect on protocol performance. Synthetic models do not realistically reflect the environment where the ad hoc networks will be deployed. In addition, mobility and traffic tools are designed independently of each other, however real trace data challenge that assumption. Indeed, recent protocol performance evaluation using real testbeds show that performance evaluations under real testbeds and simulations that use synthetic models differ significantly. In this paper we consider jointly both real mobility and traffic for protocol performance evaluation. The contributions of this work are as follows: (1) demonstrates that real mobility and traffic are interconnected; (2) announces the design and implementation of WIT –Wireless Integrated Traffic–, which includes the design of a real traffic generator; (3) shows that under real mobility and integrated traffic the performance metrics need to be re‐thought, thus we propose availability as a new ad hoc network protocol performance metric; and, finally, (4) evaluates protocol performance under synthetic and real mobility models with integrated traffic. We believe that the results of our work constitute a step forward toward benchmarking of ad hoc network performance evaluations.
Cheaper Adjoints by Reversing Address Computations
Authors: Hascoët L. , Utke J. , Naumann U.
Published: January 2015

The reverse mode of automatic differentiation is widely used in science and engineering. A severe bottleneck for the performance of the reverse mode, however, is the necessity to recover certain intermediate values of the program in reverse order. Among these values are computed addresses, which traditionally are recovered through forward recomputation and storage in memory. We propose an alternative approach for recovery that uses inverse computation based on dependency information. Address storage constitutes a significant portion of the overall storage requirements. An example illustrates substantial gains that the proposed approach yields, and we show use cases in practical applications.
Multicore Challenges and Benefits for High Performance Scientific Computing
Authors: Nielsen Ida M.B. , Janssen Curtis L.
Published: January 2015

Until recently, performance gains in processors were achieved largely by improvements in clock speeds and instruction level parallelism. Thus, applications could obtain performance increases with relatively minor changes by upgrading to the latest generation of computing hardware. Currently, however, processor performance improvements are realized by using multicore technology and hardware support for multiple threads within each core, and taking full advantage of this technology to improve the performance of applications requires exposure of extreme levels of software parallelism. We will here discuss the architecture of parallel computers constructed from many multicore chips as well as techniques for managing the complexity of programming such computers, including the hybrid message-passing/multi-threading programming model. We will illustrate these ideas with a hybrid distributed memory matrix multiply and a quantum chemistry algorithm for energy computation using Møller–Plesset perturbation theory.
Coordination Protocols for a Reliable Sensor, Actuator, and Device Network (SADN)
Authors: Ozaki Keiji , Enokido Tomoya , Takizawa Makoto
Published: January 2015

A sensor, actuator, and device network (SADN) is composed of three types of nodes, which are sensor, actuator, and actuation device nodes. Sensor nodes and actuator nodes are interconnected in wireless networks as discussed in wireless sensor and actuator networks (WSANs). Actuator nodes and device nodes are interconnected in types of networks, i.e. wireless and wired network. Sensor nodes sense an physical event and send sensed values of the event to actuator nodes. An actuator node makes a decision on proper actions on receipt of sensed values and then issue the action requests to the device nodes. A device node really acts to the physical world. For example, moves a robot arms by performing the action on receipt of the action request. Messages may be lost and nodes may be faulty. Especially, messages are lost due to noise and collision in a wireless network. We propose a fully redundant model for an SADN where each of sensor, actuator, and device functions is replicated in multiple nodes and each of sensor‐actuator and actuator‐device communication is realized in many‐to‐many type of communication protocols. Even if some number of nodes are faulty, the other nodes can perform requested tasks. Here, each sensor node sends sensed values to multiple actuator nodes and each actuator node receives sensed values from multiple sensor nodes. While multiple actuator nodes communicate with multiple replica nodes of a device. Even if messages are lost and some number of nodes are faulty, device nodes can surely receive action requests required for sensed values and the actions are performed. In this paper, we discuss a type of semi‐passive coordination (SPC) protocol of multiple actuator nodes for multiple sensor nodes. We discuss a type of active coordination protocol for multiple actuator nodes and multiple actuation device nodes. We evaluate the SPC protocol for the sensor‐actuator coordination in terms of the number of messages exchanged among actuators.
GAIML: A New Language for Verbal and Graphical Interaction in Chatbots
Authors: Pirrone Roberto , Russo Giuseppe , Cannella Vincenzo , Peri Daniele
Published: January 2015

Natural and intuitive interaction between users and complex systems is a crucial research topic in human‐computer interaction. A major direction is the definition and implementation of systems with natural language understanding capabilities. The interaction in natural language is often performed by means of systems called chatbots. A chatbot is a conversational agent with a proper knowledge base able to interact with users. Chatbots appearance can be very sophisticated with 3D avatars and speech processing modules. However the interaction between the system and the user is only performed through textual areas for inputs and replies. An interaction able to add to natural language also graphical widgets could be more effective. On the other side, a graphical interaction involving also the natural language can increase the comfort of the user instead of using only graphical widgets. In many applications multi‐modal communication must be preferred when the user and the system have a tight and complex interaction. Typical examples are cultural heritages applications (intelligent museum guides, picture browsing) or systems providing the user with integrated information taken from different and heterogenous sources as in the case of the iGoogle™ interface. We propose to mix the two modalities (verbal and graphical) to build systems with a reconfigurable interface, which is able to change with respect to the particular application context. The result of this proposal is the Graphical Artificial Intelligence Markup Language (GAIML) an extension of AIML allowing merging both interaction modalities. In this context a suitable chatbot system called Graphbot is presented to support this language. With this language is possible to define personalized interface patterns that are the most suitable ones in relation to the data types exchanged between the user and the system according to the context of the dialogue.