906 resultados para Placement of router nodes
Resumo:
A tecnologia sem fio (wireless) vem tomando conta do mundo. A cada dia mais pessoas estão trocando seus equipamentos com fio por equipamentos com a tecnologia wireless. Isso vem crescendo, devido as suas vantagens, tais como: facilidade de instalação e manutenção, redução de tempo de instalação de dispositivos, inexistência de estrutura de cabeamento, economia no custo de projetos, economia em infraestrutura, flexibilidade de configuração de dispositivos, economia no custo de montagem, flexibilidade na alteração de arquiteturas existentes e outros. Por essas facilidades supracitadas a área de automação industrial está também aumentando o seu interesse nessa tecnologia wireless. Nessa área, a segurança, confiabilidade e robustez dos dados são de suma importância. Então, para minimizar os efeitos das interferências geradas nesse meio são usadas técnicas de espalhamento em frequência e topologia em malha ou árvore para transmissão dos dados enviados pelos sensores aos nós roteadores até chegar ao gateway. Sendo assim, o posicionamento dos nós roteadores na rede em malha garantirá a menor influência dessas interferências. Esse trabalho propõe uma ferramenta de posicionamento de nós roteadores intermediários, chamado POSIMNET (Positioning Immune Network Rede Imunológica de Posicionamento), que auxilia o projetista da rede de automação industrial a encontrar a melhor configuração da rede sem fio. O POSIMNET é baseado nas redes imunológicas artificiais, que propõe criar n caminhos quaisquer ou disjuntos para as informações enviadas pelos nós sensores chegarem ao gateway, através da supressão, clonagem e reconfiguração de nós roteadores intermediários. Além disso, o algoritmo também é capaz de atender os critérios de baixo grau de falha e baixo número de retransmissão pelos roteadores. Esses critérios podem ser habilitados individualmente ou combinados com pesos iguais ou diferentes para cada um, a critério do usuário. A ferramenta POSIMNET é formada por dois módulos: (i) Rede Imunológica agrega elementos de dois modelos de redes imunológicas (SSAIS e AiNet); (ii) Campos Potenciais - posiciona os nós roteadores pelos campos potenciais, onde os sensores críticos os atraem enquanto que os obstáculos e outros roteadores os repelem.
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This paper presents a method for placement of Phasor Measurement Units, ensuring the monitoring of vulnerable buses which are obtained based on transient stability analysis of the overall system. Real-time monitoring of phase angles across different nodes, which indicates the proximity to instability, the very purpose will be well defined if the PMUs are placed at buses which are more vulnerable. The issue is to identify the key buses where the PMUs should be placed when the transient stability prediction is taken into account considering various disturbances. Integer Linear Programming technique with equality and inequality constraints is used to find out the optimal placement set with key buses identified from transient stability analysis. Results on IEEE-14 bus system are presented to illustrate the proposed approach.
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In this study, a new reactive power loss index (RPLI) is proposed for identification of weak buses in the system. This index is further used for determining the optimal locations for placement of reactive compensation devices in the power system for additional voltage support. The new index is computed from the reactive power support and loss allocation algorithm using Y-bus method for the system under intact condition and as well as critical/severe network contingencies cases. Fuzzy logic approach is used to select the important and critical/severe line contingencies from the contingency list. The inherent characteristics of the reactive power in system operation is properly addressed while determining the reactive power loss allocation to load buses. The proposed index is tested on sample 10-bus equivalent system and 72-bus practical equivalent system of Indian southern region power grid. The validation of the weak buses identification from the proposed index with that from other existing methods in the literature is carried out to demonstrate the effectiveness of the proposed index. Simulation results show that the identification of weak buses in the system from the new RPLI is completely non-iterative, thus requires minimal computational efforts as compared with other existing methods in the literature.
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In some Queensland universities, Information Systems academics have moved out of Business Faculties. This study uses a pilot SWOT analysis to examine the ramifications of Information Systems academics being located within or outside of the Business Faculty. The analysis provides a useful basis for decision makers in the School studied, to exploit opportunities and minimise external threats. For Information Systems academics contemplating administrative relocation of their group, the study also offers useful insights. The study presages a series of further SWOT analyses to provide a range of perspectives on the relative merits of having Information Systems academics administratively located inside versus outside Business faculties.
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Sugarcane orange rust, caused by Puccinia kuehnii, was once considered a minor disease in the Australian sugar industry. However, in 2000 a new race of the pathogen devastated the high-performing sugarcane cultivar Q124, and caused the industry Aus$150–210 million in yield losses. At the time of the epidemic, very little was known about the genetic and pathogenic diversity of the fungus in Australia and neighbouring sugar industries. DNA sequence data from three rDNA regions were used to determine the genetic relationships between isolates within two P. kuehnii collections. The first collection comprised only recent Australian field isolates and limited sequence variation was detected within this population. In the second study, Australian isolates were compared with isolates from Papua New Guinea, Indonesia, China and historical herbarium collections. Greater sequence variation was detected in this collection and phylogenetic analyses grouped the isolates into three clades. All isolates from commercial cane fields clustered together including the recent Australianfield isolates and the Australian historical isolate from 1898.The other two clades included rust isolates from wild and garden canes in Indonesia and PNG. These rusts appeared morphologically similar to P. kuehnii and could potentially pose a quarantine threat to the Australian sugar industry. The results have revealed greater diversity in sugarcane rusts than previously thought.
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This paper addresses a previously unconsidered history — that of Aboriginal characters in Australian soap operas. Rejecting critical approaches which have obtained even into the 1990s, it refuses to judge these characters as 'good' or 'bad' manifestations of indigeneity. Rather, using the idea that genre is a way of closing down interpretive possibilities, the paper looks at the manner in which generic expectations around soap operas produce particular valences for these representations of Aboriginality. It points to the many ways in which these indigenous characters are insistently constructed as liminal in soap operas' structural communities - simultaneously inside and outside of the group. This is seen to accord with the suggestions of Jakubowicz et al about the ways in which Aboriginal people are positioned by wider social discourses.
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Network RTK (Real-Time Kinematic) is a technology that is based on GPS (Global Positioning System) or more generally on GNSS (Global Navigation Satellite System) observations to achieve centimeter-level accuracy positioning in real time. It is enabled by a network of Continuously Operating Reference Stations (CORS). CORS placement is an important problem in the design of network RTK as it directly affects not only the installation and running costs of the network RTK, but also the Quality of Service (QoS) provided by the network RTK. In our preliminary research on the CORS placement, we proposed a polynomial heuristic algorithm for a so-called location-based CORS placement problem. From a computational point of view, the location-based CORS placement is a largescale combinatorial optimization problem. Thus, although the heuristic algorithm is efficient in computation time it may not be able to find an optimal or near optimal solution. Aiming at improving the quality of solutions, this paper proposes a repairing genetic algorithm (RGA) for the location-based CORS placement problem. The RGA has been implemented and compared to the heuristic algorithm by experiments. Experimental results have shown that the RGA produces better quality of solutions than the heuristic algorithm.
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The aim of this study was to assess the accuracy of placement of pelvic binders and to determine whether circumferential compression at the level of the greater trochanters is the best method of reducing a symphyseal diastasis. Patients were identified by a retrospective review of all pelvic radiographs performed at a military hospital over a period of 30 months. We analysed any pelvic radiograph on which the buckle of the pelvic binder was clearly visible. The patients were divided into groups according to the position of the buckle in relation to the greater trochanters: high, trochanteric or low. Reduction of the symphyseal diastasis was measured in a subgroup of patients with an open-book fracture, which consisted of an injury to the symphysis and disruption of the posterior pelvic arch (AO/OTA 61-B/C). We identified 172 radiographs with a visible pelvic binder. Five cases were excluded due to inadequate radiographs. In 83 (50%) the binder was positioned at the level of the greater trochanters. A high position was the most common site of inaccurate placement, occurring in 65 (39%). Seventeen patients were identified as a subgroup to assess the effect of the position of the binder on reduction of the diastasis. The mean gap was 2.8 times greater (mean difference 22 mm) in the high group compared with the trochanteric group (p < 0.01). Application of a pelvic binder above the level of the greater trochanters is common and is an inadequate method of reducing pelvic fractures and is likely to delay cardiovascular recovery in these seriously injured patients.
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The distribution of black leaf nodes at each level of a linear quadtree is of significant interest in the context of estimation of time and space complexities of linear quadtree based algorithms. The maximum number of black nodes of a given level that can be fitted in a square grid of size 2n × 2n can readily be estimated from the ratio of areas. We show that the actual value of the maximum number of nodes of a level is much less than the maximum obtained from the ratio of the areas. This is due to the fact that the number of nodes possible at a level k, 0≤k≤n − 1, should consider the sum of areas occupied by the actual number of nodes present at levels k + 1, k + 2, …, n − 1.
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Vialaea minutella was consistently isolated from infected mango trees showing branch dieback symptoms in northern Queensland. The fungus was identified by morphology and confirmed with molecular sequence data. This is the first report of V. minutella in Australia. The systematic position of Vialaea was confirmed to be in the Xylariales based on reconstructed LSU sequence data.
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Extrapulmonary manifestations constitute 15 to 20% of tuberculosis cases, with lymph node tuberculosis (LNTB) as the most common form of infection. However, diagnosis and treatment advances are hindered by lack of understanding of LNTB biology. To identify host response, Mycobacterium tuberculosis infected lymph nodes from LNTB patients were studied by means of transcriptomics and quantitative proteomics analyses. The selected targets obtained by comparative analyses were validated by quantitative PCR and immunohistochemistry. This approach provided expression data for 8,728 transcripts and 102 proteins, differentially regulated in the infected human lymph node. Enhanced inflammation with upregulation of T-helper1-related genes, combined with marked dysregulation of matrix metalloproteinases, indicates tissue damage due to high immunoactivity at infected niche. This expression signature was accompanied by significant upregulation of an immunoregulatory gene, leukotriene A4 hydrolase, at both transcript and protein levels. Comparative transcriptional analyses revealed LNTB-specific perturbations. In contrast to pulmonary TB-associated increase in lipid metabolism, genes involved in fatty-acid metabolism were found to be downregulated in LNTB suggesting differential lipid metabolic signature. This study investigates the tissue molecular signature of LNTB patients for the first time and presents findings that indicate the possible mechanism of disease pathology through dysregulation of inflammatory and tissue-repair processes.
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This paper addresses the problem of how to select the optimal number of sensors and how to determine their placement in a given monitored area for multimedia surveillance systems. We propose to solve this problem by obtaining a novel performance metric in terms of a probability measure for accomplishing the task as a function of set of sensors and their placement. This measure is then used to find the optimal set. The same measure can be used to analyze the degradation in system 's performance with respect to the failure of various sensors. We also build a surveillance system using the optimal set of sensors obtained based on the proposed design methodology. Experimental results show the effectiveness of the proposed design methodology in selecting the optimal set of sensors and their placement.
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There is a lot of pressure on all the developed and second world countries to produce low emission power and distributed generation (DG) is found to be one of the most viable ways to achieve this. DG generally makes use of renewable energy sources like wind, micro turbines, photovoltaic, etc., which produce power with minimum green house gas emissions. While installing a DG it is important to define its size and optimal location enabling minimum network expansion and line losses. In this paper, a methodology to locate the optimal site for a DG installation, with the objective to minimize the net transmission losses, is presented. The methodology is based on the concept of relative electrical distance (RED) between the DG and the load points. This approach will help to identify the new DG location(s), without the necessity to conduct repeated power flows. To validate this methodology case studies are carried out on a 20 node, 66kV system, a part of Karnataka Transco and results are presented.
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We use information theoretic achievable rate formulas for the multi-relay channel to study the problem of optimal placement of relay nodes along the straight line joining a source node and a destination node. The achievable rate formulas that we utilize are for full-duplex radios at the relays and decode-and-forward relaying. For the single relay case, and individual power constraints at the source node and the relay node, we provide explicit formulas for the optimal relay location and the optimal power allocation to the source-relay channel, for the exponential and the power-law path-loss channel models. For the multiple relay case, we consider exponential path-loss and a total power constraint over the source and the relays, and derive an optimization problem, the solution of which provides the optimal relay locations. Numerical results suggest that at low attenuation the relays are mostly clustered close to the source in order to be able to cooperate among themselves, whereas at high attenuation they are uniformly placed and work as repeaters. We also prove that a constant rate independent of the attenuation in the network can be achieved by placing a large enough number of relay nodes uniformly between the source and the destination, under the exponential path-loss model with total power constraint.