34 resultados para clustering and QoS-aware routing
em Consorci de Serveis Universitaris de Catalunya (CSUC), Spain
Resumo:
A survey of MPLS protection methods and their utilization in combination with online routing methods is presented in this article. Usually, fault management methods pre-establish backup paths to recover traffic after a failure. In addition, MPLS allows the creation of different backup types, and hence MPLS is a suitable method to support traffic-engineered networks. In this article, an introduction of several label switch path backup types and their pros and cons are pointed out. The creation of an LSP involves a routing phase, which should include QoS aspects. In a similar way, to achieve a reliable network the LSP backups must also be routed by a QoS routing method. When LSP creation requests arrive one by one (a dynamic network scenario), online routing methods are applied. The relationship between MPLS fault management and QoS online routing methods is unavoidable, in particular during the creation of LSP backups. Both aspects are discussed in this article. Several ideas on how these actual technologies could be applied together are presented and compared
Resumo:
Globalization involves several facility location problems that need to be handled at large scale. Location Allocation (LA) is a combinatorial problem in which the distance among points in the data space matter. Precisely, taking advantage of the distance property of the domain we exploit the capability of clustering techniques to partition the data space in order to convert an initial large LA problem into several simpler LA problems. Particularly, our motivation problem involves a huge geographical area that can be partitioned under overall conditions. We present different types of clustering techniques and then we perform a cluster analysis over our dataset in order to partition it. After that, we solve the LA problem applying simulated annealing algorithm to the clustered and non-clustered data in order to work out how profitable is the clustering and which of the presented methods is the most suitable
Resumo:
The advent of new advances in mobile computing has changed the manner we do our daily work, even enabling us to perform collaborative activities. However, current groupware approaches do not offer an integrating and efficient solution that jointly tackles the flexibility and heterogeneity inherent to mobility as well as the awareness aspects intrinsic to collaborative environments. Issues related to the diversity of contexts of use are collected under the term plasticity. A great amount of tools have emerged offering a solution to some of these issues, although always focused on individual scenarios. We are working on reusing and specializing some already existing plasticity tools to the groupware design. The aim is to offer the benefits from plasticity and awareness jointly, trying to reach a real collaboration and a deeper understanding of multi-environment groupware scenarios. In particular, this paper presents a conceptual framework aimed at being a reference for the generation of plastic User Interfaces for collaborative environments in a systematic and comprehensive way. Starting from a previous conceptual framework for individual environments, inspired on the model-based approach, we introduce specific components and considerations related to groupware.
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In order to successfully deploy multicast services in QoS-aware networks, pricing architectures must take into account the particular characteristics of multicast sessions. With this objective, we propose a charging scheme for QoS multicast services, assuming that the unicast cost of each interconnecting link is determined and that such cost is expressed in terms of quality of service (QoS) parameters. Our scheme allows determining the cost distribution of a multicast session along a cost distribution tree (CDT), and basing such distribution in those pre-existing unicast cost functions. The paper discusses in detail the main characteristics of the problem in a realistic interdomain scenario and how the proposed scheme would contribute to its solution
Resumo:
Nowadays, there are several services and applications that allow users to locate and move to different tourist areas using a mobile device. These systems can be used either by internet or downloading an application in concrete places like a visitors centre. Although such applications are able to facilitate the location and the search for points of interest, in most cases, these services and applications do not meet the needs of each user. This paper aims to provide a solution by studying the main projects, services and applications, their routing algorithms and their treatment of the real geographical data in Android mobile devices, focusing on the data acquisition and treatment to improve the routing searches in off-line environments.
Resumo:
We present a generator of random networks where both the degree-dependent clustering coefficient and the degree distribution are tunable. Following the same philosophy as in the configuration model, the degree distribution and the clustering coefficient for each class of nodes of degree k are fixed ad hoc and a priori. The algorithm generates corresponding topologies by applying first a closure of triangles and second the classical closure of remaining free stubs. The procedure unveils an universal relation among clustering and degree-degree correlations for all networks, where the level of assortativity establishes an upper limit to the level of clustering. Maximum assortativity ensures no restriction on the decay of the clustering coefficient whereas disassortativity sets a stronger constraint on its behavior. Correlation measures in real networks are seen to observe this structural bound.
Resumo:
Peer-reviewed
Resumo:
Les xarxes híbrides satèl·lit-terrestre ofereixen connectivitat a zones remotes i aïllades i permeten resoldre nombrosos problemes de comunicacions. No obstant, presenten diversos reptes, ja que realitzen la comunicació per un canal mòbil terrestre i un canal satèl·lit contigu. Un d'aquests reptes és trobar mecanismes per realitzar eficientment l'enrutament i el control de flux, de manera conjunta. L'objectiu d'aquest projecte és simular i estudiar algorismes existents que resolguin aquests problemes, així com proposar-ne de nous, mitjançant diverses tècniques d'optimització convexa. A partir de les simulacions realitzades en aquest estudi, s'han analitzat àmpliament els diversos problemes d'enrutament i control de flux, i s'han avaluat els resultats obtinguts i les prestacions dels algorismes emprats. En concret, s'han implementat de manera satisfactòria algorismes basats en el mètode de descomposició dual, el mètode de subgradient, el mètode de Newton i el mètode de la barrera logarítmica, entre d'altres, per tal de resoldre els problemes d'enrutament i control de flux plantejats.
Resumo:
The advent of the European Union has decreased the diversification benefits available from country based equity market indices in the region. This paper measures the increase in stock integration between the three largest new EU members (Hungary, the Czech Republic and Poland who joined in May 2004) and the Euro-zone. A potentially gradual transition in correlations is accommodated in a single VAR model by embedding smooth transition conditional correlation models with fat tails, spillovers, volatility clustering, and asymmetric volatility effects. At the country market index level all three Eastern European markets show a considerable increase in correlations in 2006. At the industry level the dates and transition periods for the correlations differ, and the correlations are lower although also increasing. The results show that sectoral indices in Eastern European markets may provide larger diversification opportunities than the aggregate market. JEL classifications: C32; C51; F36; G15 Keywords: Multivariate GARCH; Smooth Transition Conditional Correlation; Stock Return Comovement; Sectoral correlations; New EU Members
Resumo:
D'ençà que el sobrepès és un factor de risc per a moltes malalties mortals, la investigació ha intentat identificar els factors que fan a les persones vulnerables de la sobreingesta. Aquest treball es basa en una revisió sistemàtica d'estudis qualitatius amb la intenció de resumir l'evidència existent sobre les relacions que s'estableixen entre les emocions i el comportament alimentari. Els resultats indiquen que hi ha una correlació positiva entre emocions i ingesta, sent aquesta última, moltes vegades, influenciada per diferents estats emocionals. També existeix una correlació positiva entre estats d'ànim negatius i elecció d'aliments d'un alt contingut calòric. Els fabricants i venedors, conscients d'aquesta relació, han utilitzat aquestes necessitats humanes en el seu propi benefici. Entendre la manera en què les emocions es relacionen amb el comportament alimentari pot augmentar l'efectivitat de les intervencions dissenyades per a millorar les recomanacions i hàbits alimentaris que determinaran la salut i la qualitat de vida de la població.
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Test-based assessment tools are mostly focused on the use of computers. However, advanced Information and Communication Technologies, such as handheld devices, opens up the possibilities of creating new assessment scenarios, increasing the teachers’ choices to design more appropriate tests for their subject areas. In this paper we use the term Computing-Based Testing (CBT) instead of Computer-Based Testing, as it captures better the emerging trends. Within the CBT context, the paper is centred on proposing an approach for “Assessment in situ” activities, where questions have to be answered in front of a real space/location (situ). In particular, we present the QuesTInSitu software implementation that includes both an editor and a player based on the IMS Question and Test Interoperability specification and GoogleMaps. With QuesTInSitu teachers can create geolocated questions and tests (routes), and students can answer the tests using mobile devices with GPS when following a route. Three illustrating scenarios and the results from the implementation of one of them in a real educational situation show that QuesTInSitu enables the creation of innovative, enriched and context-aware assessment activities. The results also indicate that the use of mobile devices and location-based systems in assessment activities facilitates students to put explorative and spatial skills into practice and fosters their motivation, reflection and personal observation.
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Objective: The purpose of this paper was to compare the prevalence rates of child sexual abuse reported by [Finkelhor, D. (1994). The international epidemiology of child sexual abuse. Child Abuse & Neglect, 18 (5), 409417] with those found in recent publications in order to confirm the widespread prevalence of child sexual abuse. Methods: Relevant articles about prevalence of child sexual abuse were identified through searches of computerized databases and a handsearch of Child Abuse & Neglect and the Journal of Child Sexual Abuse. Results: Thirty-eight independent articles were identified, corresponding to 39 prevalence studies; these articles report the prevalence of childhood sexual abuse in 21 different countries, ranging from 0 to 53% for women and 0 to 60% for men. Conclusions: Comparison of the present study with that of [Finkelhor, D. (1994). The international epidemiology of child sexual abuse. Child Abuse & Neglect, 18 (5), 409417] shows a similarity between prevalence distributions; there appears to be a general pattern that remains more or less constant over the years, especially in women. Practice implications: Twelve years after the first revision study about the international prevalence of child sexual abuse, there is still a need for new data about this topic. The present study shows child sexual abuse is still a widespread problem in the society. In this research, carried out on 38 independent studies, there is new data for 21 countries over the world, being especially relevant the results obtained from other countries different from those pertaining toNorth America or Europe. It is important to point out the high prevalence found in most of the countries, so this information could be a new warning to make society and governments aware of this problem and undertake actions to prevent sexual abuse in childhood. © 2009 Elsevier Ltd. All rights reserved.
Resumo:
En la actual concepción bio-psico-social, los Trastornos del Comportamiento Alimentario (TCA) y la obesidad están plurideterminados por factores biológicos, psicológicos y socioculturales que actúan como elementos perpetuantes en el tiempo. Se pueden modificar actitudes contraproducentes con un programa de prevención multidisciplinar y disminuir de modo significativo la población con riesgo de obesidad y de padecer un TCA. Para ello, es necesario desarrollar dichos programas de prevención, previos a la atención primaria, y la estrategia para lograrlo es la intervención ante factores de riesgo, integrada en un conjunto de actividades de educación para la salud más global. Esta propuesta educativa pretende brindar a los profesores de Educación Física una revisión bibliográfica sobre la dimensión que desde la cultura occidental se tiene de los Trastornos del Comportamiento Alimentario (TCA) y la obesidad, al tiempo que promueve la reflexión sobre las posibilidades de intervención que ofrece la Educación Física desde el ámbito educativo en cuanto a la prevención de la obesidad, de los TCA, y de las conductas de riesgo. La presente propuesta de proyecto de prevención quiere destacar la función que cumplen docentes, tutores y tutoras, como acompañantes de los estudiantes, su posición privilegiada para conocerlos de cerca y estar así atentos a sus vivencias y la posibilidad de identificar oportunamente conductas no saludables en estudiantes que necesiten ciertas pautas para mejorar su estilo de vida, modificar sus habitos, o ser derivados para una atención especializada. Por ese motivo, en esta propuesta educativa se invita a los docentes y tutores a revisar sus convicciones personales y cuestionar la manera de pensar sobre la belleza física y el cuidado corporal. Esta reflexión junto a las pautas metodológicas permitirá abordar el tema de los TCA y la obesidad con tacto, respeto y la atención necesaria frente a los sentimientos de los y las estudiantes que se encuentran en un periodo de cambios importantes y con interrogantes en torno a su identidad e imagen corporal
Resumo:
With the increasing availability of various 'omics data, high-quality orthology assignment is crucial for evolutionary and functional genomics studies. We here present the fourth version of the eggNOG database (available at http://eggnog.embl.de) that derives nonsupervised orthologous groups (NOGs) from complete genomes, and then applies a comprehensive characterization and analysis pipeline to the resulting gene families. Compared with the previous version, we have more than tripled the underlying species set to cover 3686 organisms, keeping track with genome project completions while prioritizing the inclusion of high-quality genomes to minimize error propagation from incomplete proteome sets. Major technological advances include (i) a robust and scalable procedure for the identification and inclusion of high-quality genomes, (ii) provision of orthologous groups for 107 different taxonomic levels compared with 41 in eggNOGv3, (iii) identification and annotation of particularly closely related orthologous groups, facilitating analysis of related gene families, (iv) improvements of the clustering and functional annotation approach, (v) adoption of a revised tree building procedure based on the multiple alignments generated during the process and (vi) implementation of quality control procedures throughout the entire pipeline. As in previous versions, eggNOGv4 provides multiple sequence alignments and maximum-likelihood trees, as well as broad functional annotation. Users can access the complete database of orthologous groups via a web interface, as well as through bulk download.
Resumo:
This paper presents a study of correlations between the performance of trainee translators, according to their teacher’s assessment, and the quality of their self-evaluation, according to their answers to metacognitive questionnaires. Two case-studies of two consecutive editions of a course in general translation from German into Spanish are dealt with. The course involved the use of post-translation metacognitive questionnaires designed to help trainees to evaluate their translating. A selection of the questionnaires (from the strongest and the weakest performances by students for each course edition) is considered. The study focuses on one item in these questionnaires that has to do with identifying translation problems and justifying their solutions. An interpretive analysis of the trainees’ answers for this questionnaire item reveals that the best-performing students were more strategically and translationally aware in self-evaluating their own translating. Our conclusions are based on considering six parameters from the analysis of the trainees’ answers, which are tentatively regarded as indicative of the quality of their self-evaluation.