Numer czasopisma
Computer Science
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ISSN: 1508-2806
e-ISSN:
Data wydania
2012
Rocznik
Vol. 13
Numer
No. 3
Prawa dostępu
Dostęp: otwarty dostęp
Uwagi:
Prawa: CC BY 4.0 
Uznanie autorstwa 4.0 Międzynarodowe (CC BY 4.0)
Strony
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Rocznik czasopisma (rel.)
Rocznik czasopisma
Computer Science
Vol. 13 (2012)
Artykuły numeru (rel.)
Artykuł
Dostęp ograniczony
A study on the role of non-hyperlink text on web navigation
(2012) Karanam, Saraschandra; Oostendorp, Herre van; Indurkhya, Bipin
Cognitive models of web navigation have been used for evaluating websites and predicting user navigation behavior. Currently they predict the correct hyperlink by using information from the hyperlink text alone and ignore all other textual information on a webpage. The validity of this assumption is examined by investigating the role of non-hyperlink text on user navigation behavior. In the first experiment, we created two versions of a website by removing the non-hyperlink text from it. We found that there was no significant effect of non-hyperlink text on the user navigation behavior. Participants were equally accurate, selected the same set of pages to visit and spent the same amount of time on that common set with or without non-hyperlink text. This result validates the assumptions of those models of user-navigation behavior that consider information from the hyperlink text only. However, in a follow-up experiment, we included high-relevance and low-relevance pictures on the website, and repeated the experiment with and without non-hyperlink text. We found that participants were more accurate in the presence of non-hyperlink text than without it. This result suggests that the presence of pictures might prime the users to pay attention to non-hyperlink text, which increases the task accuracy.
Artykuł
Dostęp ograniczony
Identifying limits of scalability in distributed, heterogeneous, layer based monitoring concepts like SLAte
(2012) Hilbrich, Marcus; Müller-Pfefferkorn, Ralph
In this paper we present the concept of a scalable job centric monitoring infrastructure. The overall performance of this distributed, layer based architecture called SLAte can be increased by installing additional servers to adapt to the demands of the monitored resources and users. Another important aspect is to offer a uniform global view on all data which are stored distributed to provide an easy access for users or visualisation tools. Additionally we discuss the impact of these uniform access layer on scalability.
Artykuł
Dostęp ograniczony
Management methods in SLA-aware distributed storage systems
(2012) Nikolow, Darin; Słota, Renata; Lakovic, Danilo; Winiarczyk, Paweł; Pogoda, Marek; Kitowski, Jacek
Traditional data storage systems provide access to user’s data on the “best effort” basis. While this paradigm is sufficient in many use cases it becomes an obstacle for applications with Quality of Service (QoS) constraints. Service Level Agreement (SLA) is a part of the contract agreed between the service provider and the client and contains a set of well defined QoS requirements regarding the provided service and the penalties applied in case of violations. In the paper we propose a set of SLA parameters and QoS metrics relevant to data storage processes and the management methods necessary for avoiding SLA violations. A key assumption in the proposed approach is that the underlying distributed storage system does not provide functionality for resource or bandwidth reservation for a given client request.
Artykuł
Dostęp ograniczony
Automatic proxy generation and load-balancing-based dynamic choice of services
(2012) Dąbrowski, Jarosław; Feduniak, Sebastian; Baliś, Bartosz; Bartyński, Tomasz; Funika, Włodzimierz
The paper addresses the issues of invoking services from within workflows which are becoming an increasingly popular paradigm of distributed programming. The main idea of our research is to develop a facility which enables load balancing between the available services and their instances. The system consists of three main modules: a proxy generator for a specific service according to its interface type, a proxy that redirects requests to a concrete instance of the service and load-balancer (LB) to choose the least loaded virtual machine (VM) which hosts a single service instance. The proxy generator was implemented as a bean (in compliance to EJB standard) which generates proxy according to the WSDL service interface description using XSLT engine and then deploys it on a GlassFish application server using GlassFish API, the proxy is a BPEL module and load-balancer is a stateful Web Service.
Artykuł
Dostęp ograniczony
Enabling generic distributed computing infrastructure compatibility for workflow management systems
(2012) Kozlovszky, Miklós; Karoczkai, Krisztián; Márton, István; Balaskó, Ákos; Marosi, Attila; Kacsuk, Péter
Solving workflow management system’s Distributed Computing Infrastructure (DCI) incompatibility and their workflow interoperability issues are very challenging and complex tasks. Workflow management systems (and therefore their workflows, workflow developers and also their end-users) are bounded tightly to some limited number of supported DCIs, and efforts required to allow additional DCI support. In this paper we are specifying a concept how to enable generic DCI compatibility for grid workflow management systems (such as ASKALON, MOTEUR, gUSE/WS-PGRADE, etc.) on job and indirectly on workflow level. To enable DCI compatibility among the different workflow management systems we have developed the DCI Bridge software solution. In this paper we wll describe its internal architecture, provide usage scenarios to show how the developed service resolve the DCI interoperability issues between various middleware types. The generic DCI Bridge service enables the execution of jobs onto the existing major DCI platforms (such as Service Grids (Globus Toolkit 2 and 4, gLite, ARC, UNICORE), Desktop Grids, Web services, or even cloud based DCIs).
Artykuł
Dostęp ograniczony
Abstraction layer for development and deployment of cloud services
(2012) Nguyen, Binh Minh; Tran, Viet; Hluchý, Ladislav
In this paper, we will present an abstraction layer for cloud computing, which intends to simplify the manipulation with virtual machines in clouds for easy and controlled development and deployment of cloud services. It also ensures interoperability between different cloud infrastructures and allows developers to create cloud appliances easily via inheritance mechanisms.
Artykuł
Dostęp ograniczony
Interactive cloud data farming environment for military mission planning support
(2012) Kryza, Bartosz; Król, Dariusz; Wrzeszcz, Michał; Dutka, Łukasz; Kitowski, Jacek
In a modern globalised world, military and peace keeping forces often face situations which require very subtle and well planned operations taking into account cultural and social aspects of a given region and its population as well as dynamic psychological awareness related to recent events which can have impact on the attitude of the civilians. The goal of the EUSAS project is to develop a prototype of a system enabling mission planning support and training capabilities for soldiers and police forces dealing with asymmetric threat situations, such as crowd control in urban territory. In this paper, we discuss the data-farming infrastructure developed for this project, allowing generation of large amount of data from agent based simulations for further analysis allowing soldier training and evaluation of possible outcomes of different rules of engagement.
Artykuł
Dostęp ograniczony
Environment emulation for WSN testbed
(2012) Kapłoniak, Radosław; Kwiatkowski, Łukasz; Szydło, Tomasz
The development of applications for wireless sensor networks is a challenging task. For this reason, several testbed platforms have been created. They simplify the manageability of nodes by offering easy ways of programming and debugging sensor nodes. These platforms, sometimes composed of dozens of sensors, provide a convenient way for carrying out research on medium access control and data exchange between nodes. In this article, we propose the extension of the WSN testbed, which could be used for evaluating and testing the functionality of sensor networks applications by emulating a real-world environment.
Artykuł
Dostęp ograniczony
Lazy shortest path computation in dynamic graphs
(2012) Aioanei, Daniel
We address the problem of single-source shortest path computation in digraphs with non-negative edge weights subjected to frequent edge weight decreases such that only some shortest paths are requested in-between updates. We optimise a recent semidynamic algorithm for weight decreases previously reported to be the fastest one in various conditions, resulting in important time savings that we demonstrate for the problem of incremental path map construction in user-steered image segmentation. Moreover, we extend the idea of lazy shortest path computation to digraphs subjected to both edge weight increases and decreases, comparing favourably to the fastest recent state-of-the-art algorithm.
Artykuł
Dostęp ograniczony
Erlang-based sensor network management for heterogeneous devices
(2012) Nieć, Michał; Pikuła, Paweł; Mamla, Aleksander; Turek, Wojciech
The paper describes a system designed to manage and collect data from the network of heterogeneous sensors. It was implemented using Erlang OTP and CouchDB for maximum fault tolerance, scalability and ease of deployment. It is resistant to poor network quality, shows high tolerance for software errors and power failures, operates on flexible data model. Additionally, it is available to users through an Web application, which shows just how easy it is to use the server HTTP API to communicate with it. The whole platform was implemented and tested on variety of devices like PC, Mac, ARM-based embedded devices and Android tablets.