Process modeling grammars are used to create models of business processes. In this paper, we discuss how different routing symbol designs affect an individual's ability to comprehend process models. We conduct an experiment with 154 students to ascertain which visual design principles influence process model comprehension. Our findings suggest that design principles related to perceptual discriminability and pop out improve comprehension accuracy. Furthermore, semantic transparency and aesthetic design of symbols lower the perceived difficulty of comprehension. Our results inform important principles about notational design of process modeling grammars and the effective use of process modeling in practice.

Magister Scientiae - MSc / This thesis shows that mobility management protocols for infrastructure Internet may be used in a wireless mesh network environment. In this research Mobile IPv6 and Fast Handover for Hierarchical Mobile IPv6 are successfully implemented in a wireless mesh network environment. Two experiments were carried out: vertical and horizontal handover simulations. Vertical handover simulation involved a heterogeneous wireless environment comprising both wireless local area and wireless mesh networks. An OPNET Mobile IPv6 model was used to simulate the vertical handover experiment. Horizontal handover simulation involved Mobile IPv6 and Fast Handover for Hierarchical Mobile IPv6 applied in ns2 wireless mesh network. The vertical handover results show that MIPv6 is able to manage vertical handover between wireless local area and wireless mesh network. The horizontal handover results illustrate that in mesh networks, Fast Handover for Hierarchical Mobile IPv6's performance is superior to Mobile IPv6. Fast Handover for Hierarchical Mobile IPv6 generates more throughput and less delay than Mobile IPv6. Furthermore, Fast Handover for Hierarchical Mobile IPv6 drops less data packets than Mobile IPv6. The simulations indicate that even though there are multi-hop communications in wireless mesh networks, the performance of the multi-hop routing may not play a big role in the handover performance. This is so because the mesh routers are mostly static and the multi-hop routes are readily available. Thus, the total handover delay is not affected too much by the WMN hops in the paths for signaling message transmission. / South Africa

Com o crescente aumento das funcionalidades dos circuitos integrados, existe um aumento consequente da complexidade do projeto dos mesmos. O fluxo de projeto de circuitos integrados inclui em um de seus passos o roteamento, que consiste em criar fios que interconectam as células do circuito. Devido à complexidade, o roteamento é dividido em global e detalhado. O roteamento global de circuitos VLSI é uma das tarefas mais complexas do fluxo de síntese física, sendo classificado como um problema NP-completo. Neste trabalho, além de realizar um levantamento de trabalhos que utilizam as principais técnicas de paralelismo com o objetivo de acelerar o processamento do roteamento global, foram realizadas análises nos arquivos de benchmark do ISPD 2007/08. Com base nestas análises foi proposto um método que agrupa as redes para então verificar a existência de dependência de dados em cada grupo. Esta verificação de dependência de dados, que chamamos neste trabalho de colisor, tem por objetivo, criar fluxos de redes independentes umas das outras para o processamento em paralelo, ou seja, ajudar a implementação do roteamento independente de redes. Os resultados demonstram que esta separação em grupos, aliada com a comparação concorrente dos grupos, podem reduzir em 67x o tempo de execução do colisor de redes se comparada com a versão sequencial e sem a utilização de grupos. Também foi obtido um ganho de 10x ao comparar a versão com agrupamentos sequencial com a versão paralela. / With the increasing of the functionality of integrated circuits, there is a consequent increase in the complexity of the design. The IC design flow includes the routing in one of its steps, which is to create wires that interconnect the circuit cells. Because of the complexity, routing is divided into global and detailed. The global routing of VLSI circuits is one of the most complex tasks in the flow of physical synthesis and it's classified as an NP-complete problem. In this work, a parallel computing techniques survey was applied to the VLSI global routing in order to accelerate the global routing processing analyzes. This analyzes was performed on the ISPD 2007/08 benchmark files. We proposed a method that groups the networks and then check for data dependence in each group based on these analyzes. This data dependency checking, we call this checking of collider, aims to create flow nets independent of each other for processing in parallel, or help implement the independent routing networks. The results demonstrate that this separation into groups, together with the competitor comparison of groups, can reduce 67x in the collider networks runtime compared with the sequential release and without the use of groups. It was also obtained a gain of 10x when comparing the version with sequential clusters with the parallel version.

In this research, we consider the impact of spectrum fragmentation in optical single-/multi-path routing transmission on the efficiency of the elastic optical networks. O-OFDM multicarrier transmission is a promising technique that makes it possible to choose just an adequate portion of available spectrum to satisfy the requested capacity. This involves focusing on the work to reduce the fragmentation effects by dynamically updating and controlling the minimum bandwidth allocation granularity. that serves the light path requests over multipath networks. We adopt linear and nonlinear dynamic mechanisms, which are denoted as LDAɡ and NLDAɡ that are proportional to the optical link/path bandwidth fragmentation status. Simulation results show that the minimum bandwidth granularity dynamic adaptation based on the optical path fragmentation status offers improved performance over fixed minimum bandwidth allocation granularity with respect to the bandwidth blocking probability, the throughput, the network bandwidth utilization and the number of path splitting.

Network on chips (NoCs) have emerged as a panacea to solve many intercommunication issues that are imposed by the fast growing of VLSI design. NOC have been deployed as a solution for the communication delay between cores, area overhead, power consumption, etc. One of the leading parameters of speeding up the performance of system on chips (SOCs) is the efficiency of scheduling algorithms for the applications running on a SOC. In this thesis we are arguing that a global scheduling view can significantly improve latency in NoCs. This view can be achieved by having the NoC nodes communicate with each other in a predefined application-based fashion; by calculating in advance how many clock cycles the nodes need to execute and transmit packets to the network and how many clock cycles are needed for the packets to travel all the way to the destination through routers (including queuing delay). By knowing that, we could keep some of the cores stay in "Hold-On" state until the right time comes to start transmitting. This technique could lead to reduced congestion and it may guarantee that the cores do not suffer from severe resource contention, e.g. accessing memory. This task is achieved by using a network simulator (such as OPNET) and gathering statistics, so the worst case latency can be determined. Therefore, if NoC nodes can somehow postpone sending packets in a way that does not violate the deadline of their tasks, packet dropping or livelock can be avoided. It is assumed that the NoC nodes here need buffers of their own in order to hold the ready-to-transmit packets and this can be the cost of this approach.

The Internet has become an indispensable resource for today's society. It is at the center of the today's business, entertainment, and social world. However, the core of our identities on the Internet, the IP addresses that are used to send and receive data throughout the Internet, are insecure. Attackers today are able to send data purporting to be from nearly any location (IP spoofing) and to reroute data destined for victims to the attackers themselves (IP prefix hijacking). Victims of these attacks may experience denial of service, misplaced blame, and theft of their traffic. These attacks are of the utmost importance since they affect the core layer of the Internet. Although the mechanisms of the attacks are different, they are essentially different sides of the same coin; spoofing attacks forge the identity of the sender, while hijacking attacks forge the identity of the receiver. They revolve around the same underlying lack of a secure identity on the Internet. This research reviews the existing state of the art IP spoofing and IP prefix hijacking research and proposes new defenses to close the missing gaps and provide a new level of security to our identities on the Internet. This material is based upon work supported by the National Science Foundation under Grants No. CNS-0520326 and CNS-1118101. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation. This dissertation includes both previously published/unpublished and co-authored material.

Le maintien des personnes à domicile est une perspective sérieusement envisagée dans le contexte actuel de vieillissement de la population. Selon les statistiques, près d'un habitant sur trois aurait plus de 60 ans en 2050, contre un sur cinq en 2005. Cependant, les solutions actuelles de téléassistance (bouton alarme sur un collier par exemple) ont montré leurs limites. La thèse consiste à étudier des applications du futur permettant de fournir à une personne maintenue à domicile ou à l’hôpital une meilleure solution alternative fondée sur les réseaux de capteurs, capable de mesurer certains de ses paramètres physiologiques et de transmettre des données importantes aux infirmières ou médecins. Ces applications doivent s’adapter aux besoins médicaux et avoir un coût économique faible. Nous nous sommes focalisés sur des solutions de type réseaux de capteurs qui ont un coût de développement et de mise en œuvre faibles. Ce type de réseaux de capteurs offre de nouveaux services tels que la surveillance médicale et l'amélioration de la sécurité par la propagation d'alertes d'urgence. Cependant, la forte mobilité et le changement rapide de la topologie du réseau présentent un verrou scientifique et social. En outre, l'interférence de différents capteurs augmente la difficulté d'implantation de ce genre de réseaux IEEE 802.15.4. Depuis ces dernières années, plusieurs solutions ont été étudiées, comme nous le verrons dans cette thèse. Nous nous intéressons à la fiabilité de transmission dans cette thèse, car un réseau de capteurs est très limité par la capacité de calcul, de stockage et de transfert. Nous nous interrogeons dans un premier temps sur la meilleure méthode pour la livraison des données. Nous avons sélectionné les protocoles unicast et multicast issus du domaine MANET dans le but de comparer leurs avantages et inconvénients dans le contexte des applications de surveillance médicale. Nous nous sommes intéressés aux mécanismes de mise en place et au renforcement de la route dans chacun des protocoles. Les résultats de cette première étude montrent que les protocoles multicast s’adaptent mieux aux applications, car ils permettent de réduire le nombre de paquets transmis dans le réseau. Même si certains protocoles pourraient amener une meilleure performance (en ce qui concerne le débit utile) que d’autres, aucun protocole ne satisfait une application réelle. Nous travaillons sur l’exploitation d'un réseau hétérogène en distinguant les nœuds forts et les nœuds faibles. Dans ce cadre, nous avons proposé une nouvelle approche, HMR, qui permet de mieux assurer la performance du réseau par rapport aux solutions existantes. Une dernière problématique à étudier dans cette thèse est l’agrégation de données, car les données à transmettre dans le réseau sont souvent périodiquement générées avec des tailles très restreintes (quelques octets, par exemple). Nos études montrent que l’agrégation de données est une bonne solution. Cette thèse a donné lieu à deux publications en conférences internationales avec comité de lecture. / Keeping people at home is a perspective seriously considered in the current context of population aging. According to statistics, nearly one in three would have more than 60 years in 2050, against one in five in 2005. However, current solutions telecare (alarm button on a necklace, for example) have shown their limits. The thesis consists in studying future applications to provide, to a person kept at home or in the hospital, a better alternative solution based on sensor networks. A solution capable of measuring some of its physiological parameters and transmit important data nurses or doctors. These applications must adapt to the medical needs and have a low economic cost. We focused on solutions for sensor networks having a low-cost of development and implementation. This type of sensor networks offer new services such as medical monitoring and improving security by the propagation of emergency alerts. However, the high mobility and rapid change of the network topology present a scientific and social lock. Furthermore, interference of various sensors increases the difficulty of implantation of such networks IEEE 802.15.4. In recent years, several solutions have been studied, as discussed in this thesis. We are interested in the transmission reliability in this thesis, as a sensor network is very limited computing capacity, storage and transfer. We inquire in the first instance on the best method for data delivery. We selected unicast and multicast protocols from the field MANET in order to compare their advantages and disadvantages in the context of medical monitoring applications. We are interested in mechanisms of implementation and strengthening of the route in each of the protocols. The results of this first study show that the multicast protocols are better suited to these applications because they reduce the number of packets transmitted in the network. Although some protocols may lead to better performance (as regards the throughput) than others, no protocol satisfies a real application. We are working on the operation of a heterogeneous network distinguishing between strong and weak nodes. In this context, we proposed a new approach, HMR, to better ensure network performance over existing solutions. A final issue to consider in this thesis is the aggregation of data, because the data to be transmitted in the network are often periodically generated with very small size (a few bytes, for example). Our studies show that data aggregation is a good solution.

Submitted by Maike Costa (maiksebas@gmail.com) on 2016-04-27T12:05:09Z No. of bitstreams: 1 aquivo total.pdf: 6385698 bytes, checksum: e405abafe77b914dfaead617fb32ee44 (MD5) / Made available in DSpace on 2016-04-27T12:05:09Z (GMT). No. of bitstreams: 1 aquivo total.pdf: 6385698 bytes, checksum: e405abafe77b914dfaead617fb32ee44 (MD5) Previous issue date: 2015-06-18 / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / The bi-objective Pollution-Routing Problem (b-PRP) is a PRP (Pollution-Routing Problem Bekta¸s e Laporte (2011)) extension that considers separately two conflicting objectives: minimization of carbon emission costs and minimization of operational costs. To the best of our knowledge, only few papers in the literature present multi-objective analysis concerning transportation environmental issues. Due to the lack of specific methods that are capable of finding good results for this kind of problem, this dissertation aims to propose a new heuristic method for solving the b-PRP. In this method, solution sets are generated so as to represent possible scenarios for the problem. The proposed method is based on the Two-Phase Pareto Local Search (2PPLS) proposed by Lust e Teghem (2009). During the first phase of the method, efficient solutions are generated solving parametrized problems. In the second phase, each solution is explored by means of a Pareto Local Search procedure. In other to speed up the method, an efficient scheme is employed for assessing the news solutions. Despite of its simplicity, the proposed method was capable of finding a large number of efficient solutions in a reasonable time. Computational results show that the proposed approach leads to better results than those obtained by multiobjective techniques available in the literature. The quality indicators Hypervolume (H) and R Measure (R) have been used for assessing the efficient solutions sets. Because of the random behavior presented in the sequential method used to solve the parametrized problems, Mann-Whitney Nonparametric Test has been used for comparing the results. Outperformance Relations have also been used on the results analysis. We concluded that the majority of solutions generated by 2PPLS dominates those generated by others multi-objective methods found in the literature. / O Pollution-Routing Problem bi-Objetivo (b-PRP) ´e uma extens˜ao do PRP (Pollution- Routing Problem proposto por Bekta¸s e Laporte (2011)) que considera separadamente dois objetivos conflitantes: minimiza¸c˜ao dos custos com as emiss˜oes de carbono e minimiza¸c˜ao dos custos operacionais. Na literatura, poucos trabalhos apresentam an´alises multiobjetivo relacionadas aos problemas de transporte resolvidos no contexto ambiental. Devido `a aus ˆencia de m´etodos capazes de encontrar bons resultados para esses tipos de problemas, esta disserta¸c˜ao tem por objetivo desenvolver um m´etodo heur´ıstico para a resolu¸c˜ao do b-PRP. S˜ao gerados conjuntos de solu¸c˜oes eficientes, que representam os poss´ıveis trade-offs entre os objetivos. A abordagem heur´ıstica proposta ´e baseada no m´etodo Two-Phase Pareto Local Search (2PPLS). A primeira fase do m´etodo ´e dedicada `a gera¸c˜ao de um conjunto de solu¸c˜oes eficientes suportadas, atrav´es da resolu¸c˜ao de problemas multiobjetivo agregados. Na segunda fase, as solu¸c˜oes geradas na primeira fase s˜ao exploradas aplicando-se um procedimento de Pareto Local Search. Nessa fase, emprega-se uma estrutura eficiente para a avalia¸c˜ao das novas solu¸c˜oes geradas. Apesar da simplicidade do m´etodo empregado, ele foi capaz de gerar um elevado n´umero de solu¸c˜oes eficientes e em um tempo computacional aceit´avel. Os resultados computacionais mostraram que a abordagem utilizada leva a resultados melhores do que os obtidos pelas t´ecnicas dispon´ıveis na literatura. Os indicadores de qualidade Hipervolume (H) e Medida R (R) foram considerados na avalia¸c˜ao dos conjuntos de solu¸c˜oes eficientes. Devido `a natureza aleat´oria do m´etodo, os resultados foram comparados por meio do Teste N˜ao Param´etrico de Mann-Whitney. Rela¸c˜oes de desempenho ainda foram empregadas na an´alise dos resultados, e mostraram que as Fronteiras de Pareto geradas pelo 2PPLS dominam, na grande maioria dos casos, aquelas geradas por outros m´etodos existentes na literatura.

Com o crescente aumento das funcionalidades dos circuitos integrados, existe um aumento consequente da complexidade do projeto dos mesmos. O fluxo de projeto de circuitos integrados inclui em um de seus passos o roteamento, que consiste em criar fios que interconectam as células do circuito. Devido à complexidade, o roteamento é dividido em global e detalhado. O roteamento global de circuitos VLSI é uma das tarefas mais complexas do fluxo de síntese física, sendo classificado como um problema NP-completo. Neste trabalho, além de realizar um levantamento de trabalhos que utilizam as principais técnicas de paralelismo com o objetivo de acelerar o processamento do roteamento global, foram realizadas análises nos arquivos de benchmark do ISPD 2007/08. Com base nestas análises foi proposto um método que agrupa as redes para então verificar a existência de dependência de dados em cada grupo. Esta verificação de dependência de dados, que chamamos neste trabalho de colisor, tem por objetivo, criar fluxos de redes independentes umas das outras para o processamento em paralelo, ou seja, ajudar a implementação do roteamento independente de redes. Os resultados demonstram que esta separação em grupos, aliada com a comparação concorrente dos grupos, podem reduzir em 67x o tempo de execução do colisor de redes se comparada com a versão sequencial e sem a utilização de grupos. Também foi obtido um ganho de 10x ao comparar a versão com agrupamentos sequencial com a versão paralela. / With the increasing of the functionality of integrated circuits, there is a consequent increase in the complexity of the design. The IC design flow includes the routing in one of its steps, which is to create wires that interconnect the circuit cells. Because of the complexity, routing is divided into global and detailed. The global routing of VLSI circuits is one of the most complex tasks in the flow of physical synthesis and it's classified as an NP-complete problem. In this work, a parallel computing techniques survey was applied to the VLSI global routing in order to accelerate the global routing processing analyzes. This analyzes was performed on the ISPD 2007/08 benchmark files. We proposed a method that groups the networks and then check for data dependence in each group based on these analyzes. This data dependency checking, we call this checking of collider, aims to create flow nets independent of each other for processing in parallel, or help implement the independent routing networks. The results demonstrate that this separation into groups, together with the competitor comparison of groups, can reduce 67x in the collider networks runtime compared with the sequential release and without the use of groups. It was also obtained a gain of 10x when comparing the version with sequential clusters with the parallel version.

Rapporten handlar om routing och då med inriktning på interna routingprotokoll i första hand. Studien är gjord med inriktning mot operatörernas nät, där det först finns en teoridel som beskriver det olika teknologierna och protokollen. Sedan diskuteras hur det ser ut ifrån operatörernas sida och avslutas med en slutsats hur det ser ut i verkligheten idag..