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International Workshop on Design of Reliable Communication Networks (DRCN)

作者： Abdulaziz Alashaikh David Tipper Teresa Gomes Graduate Telecommunications and Networking Program University of Pittsburgh Pittsburgh PA Department of Electrical and Computer Engineering INESC Coimbra Coimbra Portugal

The concept of providing differentiated classes of resilient services over communications networks has received a lot of attention in the literature. A number of proposals tried to address the problem by provisioning different classes of services with different protection schemes. However, most of these works are applied to a single layer and lack cross layer coordination in multilayer scenarios. In addition, there is an increasing need for supporting services with very high resilience requirements over future communications networks. This, however, has to be done in a cost efficient manner and without over-engineering the network. In this paper, we introduce a novel approach that simplifies the whole design and achieves both high resilience and differentiation. Our approach, utilizes the spine concept idea of embedding a subnetwork at the physical layer with comparatively high availability link and node values [1]. This lays a foundation for differentiation between multiple classes of flows. Then, cross layer mapping and spine-aware routing are performed in a way that transfers this differentiation capability to the upper layer network and flows. We provide two joint routing-mapping optimization formulations and evaluate their performance in a multilayer scenario.

关键词： Routing Communication networks Nonhomogeneous media Resilience Reliability engineering Cross layer design

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An efficient heuristic for calculating a protected path with specified nodes

An efficient heuristic for calculating a protected path with...

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International Workshop on Reliable Networks Design and Modeling (RNDM)

作者： Lúcia Martins Teresa Gomes David Tipper INESC Coimbra DEEC Coimbra Portugal Department of Electrical and Computer Engineering University of Coimbra Coimbra Portugal Graduate Telecommunications and Networking Program University of Pittsburgh Pittsburgh PA USA

The problem of determining a path between two nodes in a network that must visit specific intermediate nodes arises in a number of contexts. For example, one might require traffic to visit nodes where it can be monitored by deep packet inspection for security reasons. In this paper a new recursive heuristic is proposed for finding the shortest loopless path, from a source node to a target node, that visits a specified set of nodes in a network. In order to provide survivability to failures along the path, the proposed heuristic is modified to ensure that the calculated path can be protected by a node-disjoint backup path. The performance of the heuristic, calculating a path with and without protection, is evaluated by comparing with an integer linear programming (ILP) formulation for each of the considered problems. The ILP solver may fail to obtain a solution in a reasonable amount of time, especially in large networks, which justifies the need for effective, computationally efficient heuristics for solving these problems. Our numerical results are also compared with previous heuristics in the literature.

关键词： Algorithm design and analysis Amplitude shift keying Integer linear programming Routing Routing protocols Heuristic algorithms Electronic mail

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Matrix system for the management of resources allocation of the Intensive Care Unit (ICU) of Felicio Rocho Hospital

Matrix system for the management of resources allocation of ...

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IEEE Canada International Humanitarian Technology Conference (IHTC)

作者： Fabricio Teixiera Coura Rose Mary de Souza Batalha Thelma Virgínia Rodrigues Nilson de Figueiredo Filho Graduate Program in Electrical Engineering Pontifical Catholic University of Minas Gerais Graduate Program in Electrical Engineering Pontificia Universidade Catolica de Minas Gerais Belo Horizonte MG BR Electronic and Telecommunications Engineering Pontifical Catholic University of Minas Gerais Brasil Electronic and Telecommunications Engineering Pontificia Universidade Catolica de Minas Gerais Belo Horizonte MG BR

This paper presents the project “Matrix System for the Management of Resources Allocation of the Intensive Care Unit (ICU) of Felicio Rocho Hospital Hospital”, which was developed in order to attend the demands of the hospital medical team. The scope of this work goes beyond the humanitarian aspects of health care. It also covers some managing aspects of the clinical setting by means of controlling the allocation of human and material resources. The project consists on the development of a monitoring system that registrates the flow of physicians and staff throughout the ICU. This system is integrated to the medical records of the clinical procedures performed on patients in the ICU. The main technological basis used in the system is infrared (IR), a simple technology and low cost, attached to the health care professionals' nametags, which enables the tracking of their presence in the ICU. The data collected on the nametags is transmitted to software (open source) that works as a communication feed to a model of management *** system provides important information regarding hospital management, such as the use of medical resources and the hospitalization period of patients, at the same time that is attached to the patient's medical record. As a result, this database would allow for an improvement in the provided services' quality once it generates useful information for a more effective hospital management. Furthermore, this paper also highlights important issues regarding the implementation of technological projects in health and emergency *** work emphasize the results of the inclusion of ethics, moral, environmental and humanistic principles in the education of engineers at the Pontifical Catholic University of Minas Gerais - PUC Minas.

关键词： Hospitals Ethics Receivers Databases Monitoring Software

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Protected shortest path visiting specified nodes

Protected shortest path visiting specified nodes

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International Workshop on Reliable Networks Design and Modeling (RNDM)

作者： Teresa Gomes Sofia Marques Lúcia Martins Marta Pascoal David Tipper INESC Coimbra Coimbra Portugal Department of Electrical and Computer Engineering University of Coimbra Coimbra Portugal Department of Mathematics Coimbra Portugal Graduate Telecommunications and Networking Program University of Pittsburgh Pittsburgh PA USA

In this paper heuristics are proposed for finding the shortest loopless path, from a source node to a target node, that visits a given set of nodes in a directed graph, such that it can be protected using a node-disjoint path. This type of problem may arise due to network management constraints. The problem of calculating the shortest path that visits a given set of nodes is at least as difficult as the traveling salesman problem, and it has not received much attention. Nevertheless an efficient integer linear programming (ILP) formulation has been recently proposed for this problem. Here, the ILP formulation is adapted to include the constraint that the obtained path will be able to be protected by a node-disjoint path. Computational experiments show that this approach, namely in large networks, may fail to obtain a solution in a reasonable amount of time. Therefore three versions of a heuristic are proposed, for which extensive computational results show that they are able to find a solution in most cases, and that the calculated solutions present an acceptable relative error regarding the cost of the optimal active path. Further the CPU time required by the heuristics is significantly smaller than the required by the used ILP solver.

关键词： Algorithm design and analysis Heuristic algorithms Amplitude shift keying Mathematical model Routing Electronic mail Complexity theory

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An effective algorithm for computing all-terminal reliability bounds

An effective algorithm for computing all-terminal reliabilit...

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作者： Silva, Jaime Gomes, Teresa Tipper, David Martins, Lúcia Kounev, Velin Department of Informatics Engineering CISUC University of Coimbra Põlo 2 Pinhal de Marrocos Coimbra3030-290 Portugal Department of Physics CFC University of Coimbra Coimbra3004-516 Portugal Department of Electrical and Computer Engineering University of Coimbra Põlo 2 Pinhal de Marrocos Coimbra3030-290 Portugal INESC Coimbra Rua Antero de Quental 199 Coimbra3000-033 Portugal Graduate Telecommunications and Networking Program University of Pittsburgh PittsburghPA15260 United States

The exact calculation of all-terminal reliability is not feasible in large networks. Hence estimation techniques and lower and upper bounds for all-terminal reliability have been utilized. Here, we propose using an ordered subset of the mincuts and an ordered subset of the minpaths to calculate an all-terminal reliability upper and lower bound, respectively. The advantage of the proposed new approach results from the fact that it does not require the enumeration of all mincuts or all minpaths as required by other bounds. The proposed algorithm uses maximally disjoint minpaths, prior to their sequential generation, and also uses a binary decision diagram for the calculation of their union probability. The numerical results show that the proposed approach is computationally feasible, reasonably accurate and much faster than the previous version of the algorithm. This allows one to obtain tight bounds when it not possible to enumerate all mincuts or all minpaths as revealed by extensive tests on real-world networks. © 2015 Wiley Periodicals, Inc. NETWORKS, Vol. 66(4), 282-295 2015.

关键词： Binary decision diagrams

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Measurements in vegetation and modeling of a radio mobile channel in an urban park

Measurements in vegetation and modeling of a radio mobile ch...

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International Symposium on telecommunications

作者： B. R. S. Mello P. A. Pinna M. S. Dias F. J. B. Fonseca L. J. Matos Graduate Program in Electrical and Telecommunications Engineering UFF Niterói Brazil

This paper presents an empirical modeling for the radio mobile signal propagation in an urban park environment obtained from measurements made at the Botanic Gardens of Fonseca, Niterói, Rio de Janeiro, Brazil, using the frequencies of 900 MHz and 2400 MHz, with two different transmitting antenna heights, 3 and 5 meters, and receiving antennas fixed at the top of a car, with 1.5 meters height. Data were acquired from two different routes and, after processing, the signal coverage in this area was studied and a single propagation model was suggested. Comparisons are made with some other worthy empirical propagation models for vegetated areas and the proposed model is applied in another urban park presenting good agreement with the measurements.

关键词： Vegetation Antenna measurements Attenuation Antennas Mathematical model Data models Frequency measurement

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A novel approach for ensuring high end-to-end availability: The spine concept

A novel approach for ensuring high end-to-end availability: ...

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10th International Conference on Design of Reliable Communication Networks, DRCN 2014

作者： Gomes, Teresa Tipper, David Alashaikh, Abdulaziz Department of Electrical and Computer Engineering University of Coimbra / INESC Coimbra 3030-290 Coimbra Portugal Graduate Telecommunications and Networking Program University of Pittsburgh Pittsburgh PA 15260 United States

ISBN: (纸本)9781479940097

telecommunications networks need to guarantee that all node pairs involved in critical service communications are highly available. Typically only a small fraction of traffic and users needs high levels of availability but this traffic often drives the network design to over engineering. In this paper we adopt a novel approach to the problem of how to provide high levels of availability in an efficient manner. The basic idea is to embed a high availability set of links and nodes (termed the spine) in the network topology and leverage protection and routing to provide differentiated classes of resilience with varying levels of availability. In this paper we first explore the spine concept through a simple example illustrating the potential benefits of the approach. Then we study how the structural properties of a network topology can be used to determine heuristics to select a suitable spine and compare this with the case where all network components have the same availability. This is followed by a numerical based study comparing the heuristics with all possible spanning tree based spines for sample topologies. Our results are a step along the path of how to best design a physical network to support protection methods in achieving high levels of availability cost efficiently. © 2014 IEEE.

关键词： Availability

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Channel characterization in the 5.8GHz band in a suburban area

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Journal of Microwaves, Optoelectronics and Electromagnetic Applications 2014年第1期13卷 97-110页

作者： Meza, Wilyam D.T. Siqueira, Gláucio L. Matos, Leni J. Center for Telecommunications Studies PUC Rio de Janeiro Brazil Graduate Program in Electrical and Telecommunications Engineering UFF Niterói Brazil

Based on signal measurements carried out in the 5.8 GHz band, which is reserved for unlicensed WiMAX in Brazil, this paper evaluates narrowband and wideband characteristics on the suburban area of Tanguá city in Rio de Janeiro State. Fading statistics, coverage and adjusted prediction model such as Hata-COST 231, SUI and UFPA were used in order to find the model that best fits the measurement data before ultimately determining that the UFPA model proved to be the best one. Temporal dispersion is studied through the delay spread and coherence band calculated from the power delay profiles obtained in the sounded channel. © 2014 SBMO/SBMag.

关键词： Delay spread Fading Power delay profile Prediction models

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A novel approach for ensuring high end-to-end availability: The spine concept

A novel approach for ensuring high end-to-end availability: ...

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International Workshop on Design of Reliable Communication Networks (DRCN)

作者： Teresa Gomes David Tipper Abdulaziz Alashaikh Department of Electrical and Computer Engineering University of Coimbra / INESC Coimbra Coimbra Portugal Graduate Telecommunications and Networking Program University of Pittsburgh Pittsburgh PA

关键词： Availability Network topology Resilience Equations Mathematical model Routing Gold

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Evolutionary Features and Parameter Optimization of Spiking Neural Networks for Unsupervised Learning

Evolutionary Features and Parameter Optimization of Spiking ...

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International Joint Conference on Neural Networks

作者： Marco Silva Adriano Koshiyama Marley Vellasco Edson Cataldo Department of Electrical Engineering Pontifical Catholic University of Rio de Janeiro (PUC-Rio) Applied Mathematics Department Graduate Program in Telecommunications Engineering Federal Fluminense University (UFF)

ISBN: (纸本)9781479914821

This paper introduces two new hybrid models for clustering problems in which the input features and parameters of a spiking neural network (SNN) are optimized using evolutionary algorithms. We used two novel evolutionary approaches, the quantum-inspired evolutionary algorithm (QIEA) and the optimization by genetic programming (OGP) methods, to develop the quantum binary-real evolving SNN (QbrSNN) and the SNN optimized by genetic programming (SNN-OGP) neuro-evolutionary models, respectively. The proposed models are applied to 8 benchmark datasets, and a significantly higher clustering accuracy compared to a standard SNN without feature and parameter optimization is achieved with fewer iterations. When comparing QbrSNN and SNN-OGP, the former performed slightly better but at the expense of increased computational effort.

关键词： Neurons Sociology Statistics Neural networks Evolutionary computation Optimization Biological cells

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