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1
Hoesel, Stan Van, i Albert Wagelmans. "On the P-coverage Problem on the Real Line". Massachusetts Institute of Technology, Operations Research Center, 1991. http://hdl.handle.net/1721.1/5221.
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Abstract: In this paper we consider the p-coverage problem on the real line. We first give a detailed description of an algorithm to solve the coverage problem without the upper bound p on the number of open facilities. Then we analyze how the structure of the optimal solution changes if the setup costs of the facilities are all decreased by the same amount. This result is used to develop a parametric approach to the p-coverage problem which runs in O(pnlogn) time, n being the number of clients. OR/MS subject classification: Analysis of algorithms, computational complexity: parametric application of dynamic programming; Dynamic programming/optimal control, applications: parametric approach to p-coverage problem on the real line; Facilities/equipment planning, location, discrete: p-coverage problem on the real line.
2
Baydogan, Mustafa Gokce. "Energy Efficient Coverage And Connectivity Problem In Wireless Sensor Networks". Master's thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/12609688/index.pdf.
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In this thesis, we study the energy efficient coverage and connectivity problem in wireless sensor networks (WSNs). We try to locate heterogeneous sensors and route data generated to a base station under two conflicting objectives: minimization of network cost and maximization of network lifetime. We aim at satisfying connectivity and coverage requirements as well as sensor node and link capacity constraints. We propose mathematical formulations and use an exact solution approach to find Pareto optimal solutions for the problem. We also develop a multiobjective genetic algorithm to approximate the efficient frontier, as the exact solution approach requires long computation times. We experiment with our genetic algorithm on randomly generated problems to test how well the heuristic procedure approximates the efficient frontier. Our results show that our genetic algorithm approximates the efficient frontier well in reasonable computation times.
3
Sambhara, Chaitanya. "P-Percent Coverage in Wireless Sensor Networks". Digital Archive @ GSU, 2008. http://digitalarchive.gsu.edu/cs_theses/56.
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Coverage in a Wireless Sensor Network reflects how well a sensor network monitors an area. Many times it is impossible to provide full coverage. The key challenges are to prolong the lifetime and ensure connectivity to provide a stable network. In this thesis we first define p-percent coverage problem in which we require only p% of the whole area to be monitored. We propose two algorithms, Connected P-Percent Coverage Depth First Search (CpPCA-DFS) and Connected P-Percent Connected Dominating Set (CpPCA-CDS). Through simulations we then compare and analyze them for their efficiency and lifetime. Finally in conclusion we prove that CpPCA-CDS provides 5 to 20 percent better active node ratio at low density. At high node density it achieves better distribution of covered area however the lifetime is only 5 to10 percent shorter then CpPCA-DFS. Overall CpPCA-CDS provides up to 30 percent better distribution of covered area.
4
Orbay, Berk. "An Interactive Evolutionary Algorithm For The Multiobjective Relocation Problem With Partial Coverage". Master's thesis, METU, 2011. http://etd.lib.metu.edu.tr/upload/12613196/index.pdf.
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In this study, a bi-objective capacitated facility location problem is presented which includes partial coverage concept and relocation of facility nodes. In partial coverage, a predefined distance between a demand node and a facility node is assumed to be fully covered. After the predefined distance, the service level commences to decay linearly. The problem is designed to consider the existence of already functioning facility nodes. It is allowed to close these existing facilities and open new facilities in potential sites. However, existing facility nodes are strongly favored against new facility nodes. The objectives are the maximization of the weighted total coverage and the minimization of number of facility nodes. A novel interactive multi-objective evolutionary algorithm is proposed to solve this problem, I-TREA. I-TREA is originated from NSGA-II and designed for interactive methods benefiting from quality infeasible solutions. The performance of I-TREA is benchmarked with a modified version of NSGA-II on randomly generated problems with various sizes and utility functions.
5
Yin, Li. "Sensor network coverage and data aggregation problem: solutions toward the maximum lifetime". Diss., Rolla, Mo. : University of Missouri-Rolla, 2007. http://scholarsmine.mst.edu/thesis/pdf/Yin_09007dcc803c1aa0.pdf.
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Thesis (M.S.)--University of Missouri--Rolla, 2007.Vita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed November 26, 2007) Includes bibliographical references (p. 51-55).
6
Vu, Chinh Trung. "An Energy-Efficient Distributed Algorithm for k-Coverage Problem in Wireless Sensor Networks". Digital Archive @ GSU, 2007. http://digitalarchive.gsu.edu/cs_theses/40.
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Wireless sensor networks (WSNs) have recently achieved a great deal of attention due to its numerous attractive applications in many different fields. Sensors and WSNs possesses a number of special characteristics that make them very promising in many applications, but also put on them lots of constraints that make issues in sensor network particularly difficult. These issues may include topology control, routing, coverage, security, and data management. In this thesis, we focus our attention on the coverage problem. Firstly, we define the Sensor Energy-efficient Scheduling for k-coverage (SESK) problem. We then solve it by proposing a novel, completely localized and distributed scheduling approach, naming Distributed Energy-efficient Scheduling for k-coverage (DESK) such that the energy consumption among all the sensors is balanced, and the network lifetime is maximized while still satisfying the k-coverage requirement. Finally, in related work section we conduct an extensive survey of the existing work in literature that focuses on with the coverage problem.
7
Toreyen, Ozgun. "Hierarchical Maximal Covering Location Problem With Referral In The Presence Of Partial Coverage". Master's thesis, METU, 2007. http://etd.lib.metu.edu.tr/upload/12608771/index.pdf.
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We consider a hierarchical maximal covering location problem to locate p health centers and q hospitals in such a way that maximum demand is covered, where health centers and hospitals have successively inclusive hierarchy. Demands are 3 types: demand requiring low-level service only, demand requiring high-level service only, and demand requiring both
levels of service at the same time. All types of requirements of a demand point should be either covered by hospital providing both levels of service or referred to hospital via health center since a demand point is not covered unless all levels of requirements are satisfied. Thus, a health center cannot be opened unless it is suitable to refer its covered demand to a hospital.
Referral is defined as coverage of health centers by hospitals.
We also added partial coverage to this complex hierarchic structure, that is, a demand point is fully covered up to the minimum critical distance, non-covered after the maximum critical distance and covered with a decreasing quality while increasing distance to the facility between minimum and maximum critical distances.
We developed an MIP formulation to solve the Hierarchical Maximal Covering Location Problem with referral in the presence of partial coverage. We solved small-size problems
optimally using GAMS. For large-size problems we developed a Genetic Algorithm that gives near-optimal results quickly. We tested our Genetic Algorithm on randomly generated problems of sizes up to 1000 nodes.
8
Hsieh, Pei-Shan, i Pei-Shan Hsieh. "Investigating the Maximal Coverage by Point-based Surrogate Model for Spatial Facility Location Problem". Diss., The University of Arizona, 2016. http://hdl.handle.net/10150/623182.
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Spatial facility location problems (SFLPs) involve the placement of facilities in continuous demand regions. One approach to solving SFLPs is to aggregate demand into discrete points, and then solve the point-based model as a conventional facility location problem (FLP) according to a surrogate model. Solution performance is measured in terms of the percentage of continuous space actually covered in the original SFLP. In this dissertation I explore this approach and examine factors contributing to solution quality. Three error sources are discussed: point representation spacing, multiple possible solutions to the surrogate point-based model, and round-off errors induced by the computer representation of numbers. Some factors—including boundary region surrogate points and surrogate point location—were also found to make significant contributions to coverage errors. A surrogate error measure using a point-based surrogate model was derived to characterize relationships among spacing, facility coverage area, and spatial coverage error. Locating continuous space facilities with full coverage is important but challenging. Demand surrogate points were initially used as a continuous space for constructing the MIP model, and a point-based surrogate FLP was enhanced for extracting multiple solutions with additional constraints that were found to reduce coverage error. Next, a best initial solution was applied to a proposed heuristic algorithm to serve as an improvement procedure. Algorithm performance was evaluated and applied to a problem involving the location of emergency warning sirens in the city of Dublin, Ohio. The effectiveness of the proposed method for solving this and other facility location/network design problems was demonstrated by comparing the results with those reported in recently published papers.
9
Duldig, Paul. "The extent of private health insurance coverage in Australia : public problem or private choice? /". Title page, contents and introduction only, 1985. http://web4.library.adelaide.edu.au/theses/09EC/09ecd881.pdf.
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10
Silav, Ahmet. "Bi-objective Facility Location Problems In The Presence Of Partial Coverage". Master's thesis, METU, 2009. http://etd.lib.metu.edu.tr/upload/2/12610681/index.pdf.
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In this study, we propose a bi-objective facility location model that considers both partial coverage and service to uncovered demands. In this model, it is assumed that the demand nodes within the predefined distance of opened facilities are fully covered and after that distance the coverage level linearly decreases. The objectives are the maximization of the sum of full and partial coverage the minimization of the maximum distance between uncovered demand nodes and their closest opened facilities. We apply two existing Multi Objective Genetic Algorithms (MOGAs),
NSGA-II and SPEA-II to the problem. We determine the drawbacks of these MOGAs and develop a new MOGA called modified SPEA-II (mSPEA-II) to avoid the drawbacks. In this method, the fitness function of SPEA-II is modified and the
crowding distance calculation of NSGA-II is used. The performance of mSPEA-II is tested on randomly generated problems of different sizes. The results are compared
with the solutions resulting from NSGA-II and SPEA-II. Our experiments show that mSPEA-II outperforms both NSGA-II and SPEA-II.
11
Rahim, Fatih. "A Variable Neighborhood Search Procedure For The Combined Location With Partial Coverage And Selective Traveling Salesman Problem". Master's thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/3/12611949/index.pdf.
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In this study, a metaheuristic procedure, particularly a variable neighborhood search procedure, is proposed to solve the combined location and selective traveling salesman problem in glass recycling. The collection of used glass is done by a collecting vehicle that visits a number of predefined collection centers, like restaurants and hospitals that are going to be referred to as compulsory points. Meanwhile, it is desired to locate a predetermined number of bottle banks to
residential areas. The aim is to determine the location of these bottle banks and the route of the collecting vehicle so that all compulsory points and all bottle banks are visited and the maximum profit is obtained. Population zones are defined in residential areas and it is assumed that the people in a particular population zone will recycle their used glass to the closest bottle bank that fully or partially covers their zone. A Variable Neighborhood Search algorithm and its variant have been utilized for the solution of the problem. Computational
experiments have been made on small and medium scale test problems, randomly generated and adapted from the literature.
12
Vu, Chinh Trung. "Distributed Energy-Efficient Solutions for Area Coverage Problems in Wireless Sensor Networks". Digital Archive @ GSU, 2009. http://digitalarchive.gsu.edu/cs_diss/37.
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Wireless sensor networks (WSNs) have recently attracted a great deal of attention due to their numerous attractive applications in many different fields. Sensors and WSNs possess a number of special characteristics that make them very promising in a wide range of applications, but they also put on them lots of constraints that make issues in sensor network particularly challenging. These issues may include topology control, routing, coverage, security, data management and many others. Among them, coverage problem is one of the most fundamental ones for which a WSN has to watch over the environment such as a forest (area coverage) or set of subjects such as collection of precious renaissance paintings (target of point coverage) in order for the network to be able to collect environment parameters, and maybe further monitor the environment. In this dissertation, we highly focus on the area coverage problem. With no assumption of sensors’ locations (i.e., the sensor network is randomly deployed), we only consider distributed and parallel scheduling methods with the ultimate objective of maximizing network lifetime. Additionally, the proposed solutions (including algorithms, a scheme, and a framework) have to be energy-efficient. Generally, we investigate numerous generalizations and variants of the basic coverage problem. Those problems of interest include k-coverage, composite event detection, partial coverage, and coverage for adjustable sensing range network. Various proposed algorithms. In addition, a scheme and a framework are also suggested to solve those problems. The scheme, which is designed for emergency alarming applications, specifies the guidelines for data and communication patterns that significantly reduce the energy consumption and guarantee very low notification delay. For partial coverage problem, we propose a universal framework (consisting of four strategies) which can take almost any complete-coverage algorithm as an input to generate an algorithm for partial coverage. Among the four strategies, two pairs of strategies are trade-off in terms of network lifetime and coverage uniformity. Extensive simulations are conducted to validate the efficiency of each of our proposed solutions.
13
Wei, Hu. "SOLVING CONTINUOUS SPACE LOCATION PROBLEMS". The Ohio State University, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=osu1205514715.
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14
Zhang, Xiao. "Confidence Intervals for Population Size in a Capture-Recapture Problem". Digital Commons @ East Tennessee State University, 2007. https://dc.etsu.edu/etd/2022.
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In a single capture-recapture problem, two new Wilson methods for interval estimation of population size are derived. Classical Chapman interval, Wilson and Wilson-cc intervals are examined and compared in terms of their expected interval width and exact coverage properties in two models. The new approach performs better than the Chapman in each model. Bayesian analysis also gives a different way to estimate population size.
15
Pazand, Babak. "Location-free node scheduling schemes for energy efficient, fault tolerant and adaptive sensing in wireless sensor networks". University of Western Australia. School of Computer Science and Software Engineering, 2008. http://theses.library.uwa.edu.au/adt-WU2008.0185.
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Node scheduling is one of the most effective techniques to maximize the lifetime of a wireless sensor network. It is the process of selecting a subset of nodes to monitor the sensor field on behalf of redundant nodes. At every round of the scheduling a small group of nodes are active while the rest of the sensor nodes are in sleep mode. In this thesis, we propose a novel node scheduling solution for wireless sensor networks. The main characteristic of our approach is its independence from location information as well as distance information. Moreover, it does not rely on unrealistic circular radio propagation models. In order to have a comprehensive solution, we have considered different relations between sensing range and transmission range. When these ranges are equal in addition to the case that transmission range is higher than sensing range, we devise a node scheduling scheme based on the concept of Minimum Dominating Set. Two heuristics are presented to determine a collection of minimum dominating sets of the graph of the wireless sensor network. At each round of the scheduling only one set is active. Minimum dominating sets are scheduled to be rotated periodically. Moreover, every set is synchronized prior to the end of its active period in order to minimize the effect of clock drift of sensor nodes. Two components are considered to address node failures during the on-duty period of minimum dominating sets. These are probing environment and adaptive sleeping. The former is responsible for probing the working nodes of the active set to detect any node failure. The latter adjusts the frequency of probing for minimizing the overhead of probing while preserving an adequate level of robustness for discovery of node failure. This framework is based on the PEAS protocol that has been developed by Fan Ye et al. [98, 99]. We propose a different node scheduling scheme with a three-tier architecture for the case that sensing range is higher than transmission range. The coverage tier includes a set of nodes to monitor the region of the interest. We propose a heuristic to determine a collection of d-dominating sets of the graph of the wireless sensor network. At every round of the scheduling one d-dominating set forms the coverage tier. Connectivity tier consists of sensor nodes that relay the data collected at the coverage tier back to the base station. Finally, the coverage management tier is responsible for managing different patterns of coverage such as cyclic or uniform coverage.
16
Dürr, Hans-Bernd. "Distributed Positioning of Autonomous Mobile Sensors with Application to the Coverage Problem : A Game Theoretic Approach to Multi-Agent Systems". Thesis, KTH, Reglerteknik, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-105128.
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In this thesis, general problems are considered where a group of agents should autonomously position themselves in such a way that a global objective function is maximized, whereas each agent uses only the measurement of its own utility function. Specially constructed extremum seeking schemes for single and multi-agent systems are presented, where the agents have only access to the current value of their individual utility functions and do not know the analytical model of the global or local objectives. By using an approximative system that is calculated using a methodology based on Lie brackets, practical stability of an equilibrium point is proved for the single agent as well as for the multi-agent case. The motion dynamics of the agents are modeled as single integrators, double integrators and unicycles. A potential game approach is used in order to deduce conditions under which the whole group of agents converges to a region arbitrary close to the maximum of a global objective function, that coincides with the Nash equilibrium of the game. As an application of the proposed algorithms, the sensor coverage problem is introduced. In this problem, a group of autonomous sensors is meant to position themselves such that a certain region is covered optimally, in the sense that the amount of detected events appearing in this region, is maximized. The problem is interpreted as a potential game where individual utility functions for each sensor are constructed in a way suitable for the direct application of the proposed optimization methodology.
17
Karaman, Mesut. "A Genetic Algorithm For The Multi-level Maximal Covering Ambulance Location Problem". Master's thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/3/12610099/index.pdf.
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The emergency medical services (EMS) provide the preliminary assistance and transportation for patients in need of urgent medical care in order to decrease the mortality rate and reduce the non-reversible effects of injuries. Since the objective is directly related to the human life, the value of the proposed solutions in order to improve the performance of EMS is highly welcomed. Mainly, there are three problems that EMS managers face with: location, allocation and redeployment of the EMS facilities/vehicles. Most of the studies in EMS literature focus on accurately modeling the probabilistic nature of the availability of an ambulance when it is called for. However, trivial changes in model parameters or estimates could dramatically change the optimal allocations generated by the probabilistic models and hence make the model invalid. In this study, we formulate the ambulance location problem as a deterministic multi-level maximal coverage model by which the total demand is tried to be covered as many as possible at multiple levels. Both a mathematical programming model and genetic algorithm-based heuristic approaches are proposed for the problem. The results indicate that the genetic algorithm-based solutions give reliable (near-optimal) and robust results in reasonable computational times for the problem. Moreover, the tradeoffs between the two performance measures, &lsquoresponsiveness&rsquo
and &lsquo
preparedness&rsquo
, are searched for
and our approaches with multi-level coverage are compared against the multiple coverage approaches in terms of these performance measures.
18
Kantharaj, Krithica. "Evaluating Coverage Models for Emergency Services: A Case Study of Emergency Siren Placement in Lucas County, OH". University of Toledo / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1384525360.
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Polat, Esra. "A Location And Routing-with-profit Problem In Glass Recycling". Master's thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/12610221/index.pdf.
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In this study, our aim is to determine the locations of bottle banks used in collecting recycled glass. The collection of recycled glass is done by a fleet of vehicles that visit some predetermined collection points, like restaurants and hospitals. The location of bottle banks depends on the closeness of the banks to the population zones where the recycled class is generated, and to the closeness of the banks to the predetermined collection points. A mathematical model, which combines the maximal covering problem in the presence of partial coverage and vehicle routing problem with profits, is presented. Heuristic procedures are proposed for the solution of the problem. Computational results based on generated test problems are provided. We also discuss a case study, where bottle banks are located in Yenimahalle, a district of Ankara
20
Aguiar, Alexei Barbosa de. "Tackling the problem of dynamic coverage and connectivity in wireless sensor networks with an extended version of the generate an dsolve methodology". Universidade de Fortaleza, 2009. http://dspace.unifor.br/handle/tede/84413.
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Previous issue date: 2009-12-28Wireless sensor networks (WSNs) are very usefull in a wide range of applications. However, the sensor nodes that composes these WSNs are very limited devices. Their batteries cannot supply energy for a lifetime as long as desired. In a particular scenario, the areas where these devices are deployed are inaccessible so these batteries replacements are unfeasible. In this situation the energy consumption plays a very important role and must be well optimized. Recent literature presented an integer programming model for optimizing this energy consumption. The Generate and Solve is a new hybrid methodology. The integrative collaboration of Genetic Algorithms and Linear Integer Programming merged their strong points and offered excellent results on cutting and packing problem domains. However, its original implementation had some problems which limits the results, one of them is the density explosion. This methodology has been adapted and enhanced to fix these problems and extend the capacity of this model to larger problem instances. Thus, the WSN lifetime can be much longer than before. Comparing the results against literature, the WSN lifetime planned by Generate and Solve is 150% longer and it is capable of handling problem instances with a number of sensor nodes 125% larger. Keywords: Wireless sensor networks, Optimization, Hybridization, Genetic Algorithms, Linear Integer Programming.
Redes de sensores sem fios (RSSF) são muito úteis em uma ampla gama de aplicações. Entretanto, os nós sensores que compõem essas RSSF's são dispositivos muito limitados. Suas baterias não podem suprir a energia de uma vida útil tão longa quanto desejada. Em um cenário particular, as áreas nas quais estes dispositivos são instalados são inacessíveis, logo, as trocas dessas baterias são inviáveis. Nesta situação, o consumo de energia tem um papel muito importante e deve ser bem otimizado. Uma literatura recente apresentou um modelo de programação inteira para otimizar este consumo de energia. A Gerar e Resolver é uma nova metodologia híbrida. A colaboração integrativa entre algoritmos genéticos e programação linera inteira fundiu os seus pontos fortes e ofereceu exelentes resultados em domínios de cortes e empacotamento. Entretanto, sua implementação original teve alguns problemas os quais limitam os resultados, um deles é a explosão da densidade. Esta metodologia foi adaptada e melhorada para corrigir esses problemas e extender a capacidade deste modelo para instancias de problemas maiores. Desta forma, a vida útil da RSSF pode ser bem maior que anteriormente. Comparando os resultados com a literatura, o tempo de vida da RSSF planejada pela Gerar e Resolver é 150% mais longa e ela é capaz de lidar com instâncias de problemas com um número de nós sensores 125% maior. Palavras-chave: Redes de sensores sem fios, Otimização, Hibridização, Algorítmos Genéticos, Programação Linear Inteira.
21
Araújo, André Ricardo Melo. "Heurísticas para o problema de cobertura em redes de sensores sem fio hierárquicas com sorvedouro móvel". Universidade Federal do Amazonas, 2013. http://tede.ufam.edu.br/handle/tede/2906.
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Andre Ricardo Melo Araujo.pdf: 3722790 bytes, checksum: 1876d821e1e927795304f1c1ee7bbb67 (MD5)
Previous issue date: 2013-03-01FAPEAM - Fundação de Amparo à Pesquisa do Estado do Amazonas
Wireless Sensor Network (WSN) is a special kind of ad hoc networks composed of devices capable of processing, storing, sensing the environment, and transmitting data via wireless communication interface. The sensor nodes have several limitations, among them the capacity of energy because to the reduced size. For this reason, many searches have been done with a view to improving the energy consumption of sensor nodes. This work aims to address the Problem of Coverage, Clustering and Routing with Mobile Sink (PCAR-SM, in portuguese Problema de Cobertura, Agrupamento e Roteamento com Sorvedouro Móvel) in WSN with mobile sink consisting of: given a set of sensor nodes and a monitoring area, develop algorithms to find the best subset of sensor nodes to cover the monitoring area, group them in a smaller number of clusters and find the shortest route to mobile sink navigate. The PCAR-SM is a strategy used to reduce the energy consumption of sensor nodes, data collisions, interference and redundant data in networks with high concentration of sensor nodes per area. The purpose of this paper is to solve each problem separately and together, in order to evaluate the impact of each problem on the other. The Coverage Problem has been solved with two metaheuristics: an Genetic Algorithm (GA) and a Greedy Randomized Adaptive Search Procedure (GRASP) algorithm. In the latter we used two representations of solution: (a) representation by sensor, where each element of the solution vector represents a sensor node that must be switched on or off; (b) representation by demand, where each element of the solution vector represents a demand point will indicate which sensor node cover it. The AG uses only the representation by demand. The computational results for Coverage Problem used the benchmark of Beasley s OR Library and it was possible seen that the GRASP with representation by demand achieved better results than the GA and the GRASP with representation by sensor when the optimization criterion is to minimize the total cost of each sensor node used in the solution. For Clustering Problem was created approach of virtual grids. In this approach, we divide the area into grids and clusters are formed by a set of adjacent grids (maximum 5 grids in group) forming a cross schematic. The aim of the problem is to minimize the number of clusters in the area. With this approach, we can model the Clustering Problem as a Set Cover Problem (SCP) without overlapping (an element does not belong to more than one set), which was treated by a greedy heuristic called Greedy Clustering Algorithm (GCA). The virtual grids proved to be a good solution because it is simple to identify a node which grid it belongs. Its simplicity also makes it a appropriate method for a distributed version. The Routing Problem of sink was modeled as the Travelling Salesman Problem (TSP), where the mobile sink part of a corner of the monitoring area, runs through the area visiting all clusters and returns to the starting point. For this, we propose two greedy approaches based on nearest neighbor, the Routing Greedy Algorithm - Center (RGA-C) and Routing Greedy Algorithm - Border (RGA-B). The route of the sink was also solved by a heuristic based on algorithm Centralized Spatial Partitioning (CSP). In CSP approach, the route is fixed and reminds the movement of a snake. The results show that fixed route produces a path with smaller size compared to the greedy heuristic for TSP. We analyze also the PCAR-SM, creating heuristic strategies. The union of the Clustering Problem and Routing Problem proved more beneficial in relation to the size of the sink s route. The union of Coverage Problem and Clustering Problem only proved beneficial when the communication radius was about 3,9 times greater than the sensing radius. Our results show that solve problems together allows some changes in the algorithms will lead to better results.
As Redes de Sensores Sem Fio (RSSFs) são um tipo especial de redes ad hoc constituídas por dispositivos capazes de processar, armazenar, sensoriar o ambiente e transmitir dados via interface de comunicação sem fio, denominados nós sensores. Os nós sensores possuem várias limitações, dentre elas, a capacidade de energia devido ao tamanho reduzido. Por isto, muitas pesquisas foram feitas tendo em vista a melhoria no consumo de energia dos nós sensores. Este trabalho tem como objetivo tratar o Problema de Cobertura, Agrupamento e Roteamento com Sorvedouro Móvel (PCAR-SM) em RSSF com nó sorvedouro móvel, que consiste em: dado um conjunto de nós sensores e uma área de monitoramento, desenvolver algoritmos para encontrar o melhor subconjunto de nós sensores que cubra a área de monitoramento, juntá-los no menor número de grupos possíveis e encontrar a menor rota para um nó sorvedouro móvel percorrer. O PCAR-SM é uma estratégia utilizada para diminuir o consumo de energia dos nós sensores, a colisão de dados, as interferências e os dados redundantes em redes com alta concentração de nós sensores por área. A proposta deste trabalho é resolver cada problema separadamente e em conjunto, de modo a avaliar o impacto de cada problema na solução do outro. O Problema de Cobertura foi resolvido com duas metaheurísticas: um Algoritmo Genético (AG) e um algoritmo Greedy Randomized Adaptive Search Procedure (GRASP). Neste último foram utilizadas duas representações de solução: (a) representação por sensor, onde cada elemento do vetor de solução representa um nó sensor que estará ligado ou desligado; (b) representação por demanda, onde cada elemento do vetor de solução representa um ponto de demanda no qual indicará qual o nó sensor o cobre. O AG utiliza apenas a representação por demanda. Os resultados computacionais para o Problema de Cobertura utilizaram o benchmark da Beasley s OR Library e foi possível constatar que o GRASP com representação por demanda obteve melhores resultados que o AG e o GRASP com representação por sensor quando o critério de otimização é minimizar a soma total dos custos de cada nó sensor utilizado na solução. Para o Problema de Agrupamento foi criada uma abordagem de grades virtuais. Nesta abordagem dividimos a área em grades e os grupos são formados por um conjunto de grades adjacentes (no máximo 5 grades) formando um esquema de cruz. O objetivo do problema é minimizar o número de grupos na área. A partir desta abordagem, pode-se modelar o Problema de Agrupamento como um Problema de Cobertura de Conjuntos (PCC) sem sobreposição (um elemento não pertence a mais de um conjunto), que foi tratada por uma heurística gulosa denominada Greedy Clustering Algorithm (GCA). Os grades virtuais provou ser uma boa solução por ser simples para um nó identificar a qual grade ele pertence. Sua simplicidade ainda o torna uma método adequado para uma versão distribuída. O Problema de Roteamento do nó sorvedouro foi modelado como o Problema do Caixeiro Viajante (PCV), onde o nó sorvedouro móvel parte de um canto da área de monitoramento, percorre a área visitando todos os grupos e retorna ao ponto inicial. Para isto, propomos duas abordagens gulosas baseadas no vizinho mais próximo, o Routing Greedy Algorithm - Center (RGA-C) e o Routing Greedy Algorithm - Border (RGA-B). A rota do nó sorvedouro também foi resolvida por uma heurística baseada no algoritmo Centralized Spatial Partitioning (CSP). Na abordagem CSP, a rota é fixa e lembra o movimento de uma cobra. Os resultados mostram que a rota fixa gera um percurso com tamanho menor em comparação com as heurísticas gulosas para o PCV. Analisamos, ainda, o PCAR-SM, criando estratégias heurísticas. Aunião dos Problema de Agrupamento e Roteamento, provou ser mais benéfica em relação ao tamanho da rota do nó sorvedouro, já a união do Problema de Cobertura com o Problema de Agrupamento só mostrou ser benéfica quando o raio de comunicação era aproximadamente 3, 9 vezes maior que o raio de sensoriamento. Nossos resultados, mostram que resolver os problemas em conjunto permite que algumas mudanças nos algoritmos levem a melhores resultados.
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Hua, Liyan. "Shortest Path - Capacitated Maximum Covering Problems". The Ohio State University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=osu1275477591.
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Conradi, Michael C. "The social construction of squeegee kids as a law and order problem in neo-conservative Ontario, a content analysis of press coverage, 1995-1998". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ60674.pdf.
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Mohammad, Maruf. "Cellular diagnostic systems using hidden Markov models". Diss., Virginia Tech, 2003. http://hdl.handle.net/10919/29520.
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Radio frequency system optimization and troubleshooting remains one of the most challenging aspects of working in a cellular network. To stay competitive, cellular providers continually monitor the performance of their networks and use this information to determine where to improve or expand services. As a result, operators are saddled with the task of wading through overwhelmingly large amounts of data in order to trouble-shoot system problems. Part of the difficulty of this task is that for many complicated problems such as hand-off failure, clues about the cause of the failure are hidden deep within the statistics of underlying dynamic physical phenomena like fading, shadowing, and interference. In this research we propose that Hidden Markov Models (HMMs) be used as a method to infer signature statistics about the nature and sources of faults in a cellular system by fitting models to various time-series data measured throughout the network. By including HMMs in the network management tool, a provider can explore the statistical relationships between channel dynamics endemic to a cell and its resulting performance.
This research effort also includes a new distance measure between a pair of HMMs that approximates the Kullback-Leibler divergence (KLD). Since there is no closed-form solution to calculate the KLD between the HMMs, the proposed analytical expression is very useful in classification and identification problems. A novel HMM based position location technique has been introduced that may be very useful for applications involving cognitive radios.Ph. D.
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Mohammad, Maruf H. "Cellular diagnostic systems using hidden Markov models". Diss., Virginia Tech, 2006. http://hdl.handle.net/10919/29520.
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Radio frequency system optimization and troubleshooting remains one of the most challenging aspects of working in a cellular network. To stay competitive, cellular providers continually monitor the performance of their networks and use this information to determine where to improve or expand services. As a result, operators are saddled with the task of wading through overwhelmingly large amounts of data in order to trouble-shoot system problems. Part of the difficulty of this task is that for many complicated problems such as hand-off failure, clues about the cause of the failure are hidden deep within the statistics of underlying dynamic physical phenomena like fading, shadowing, and interference. In this research we propose that Hidden Markov Models (HMMs) be used as a method to infer signature statistics about the nature and sources of faults in a cellular system by fitting models to various time-series data measured throughout the network. By including HMMs in the network management tool, a provider can explore the statistical relationships between channel dynamics endemic to a cell and its resulting performance.
This research effort also includes a new distance measure between a pair of HMMs that approximates the Kullback-Leibler divergence (KLD). Since there is no closed-form solution to calculate the KLD between the HMMs, the proposed analytical expression is very useful in classification and identification problems. A novel HMM based position location technique has been introduced that may be very useful for applications involving cognitive radios.Ph. D.
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Matos, Inês Pereira de. "Limited range coverage problems". Doctoral thesis, Universidade de Aveiro, 2009. http://hdl.handle.net/10773/2946.
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Doutoramento em MatemáticaTal como o título indica, esta tese estuda problemas de cobertura com alcance limitado. Dado um conjunto de antenas (ou qualquer outro dispositivo sem fios capaz de receber ou transmitir sinais), o objectivo deste trabalho é calcular o alcance mínimo das antenas de modo a que estas cubram completamente um caminho entre dois pontos numa região. Um caminho que apresente estas características é um itinerário seguro. A definição de cobertura é variável e depende da aplicação a que se destina. No caso de situações críticas como o controlo de fogos ou cenários militares, a definição de cobertura recorre à utilização de mais do que uma antena para aumentar a eficácia deste tipo de vigilância. No entanto, o alcance das antenas deverá ser minimizado de modo a manter a vigilância activa o maior tempo possível. Consequentemente, esta tese está centrada na resolução deste problema de optimização e na obtenção de uma solução particular para cada caso. Embora este problema de optimização tenha sido investigado como um problema de cobertura, é possível estabelecer um paralelismo entre problemas de cobertura e problemas de iluminação e vigilância, que são habitualmente designados como problemas da Galeria de Arte. Para converter um problema de cobertura num de iluminação basta considerar um conjunto de luzes em vez de um conjunto de antenas e submetê-lo a restrições idênticas. O principal tema do conjunto de problemas da Galeria de Arte abordado nesta tese é a 1-boa iluminação. Diz-se que um objecto está 1-bem iluminado por um conjunto de luzes se o invólucro convexo destas contém o objecto, tornando assim este conceito num tipo de iluminação de qualidade. O objectivo desta parte do trabalho é então minimizar o alcance das luzes de modo a manter uma iluminação de qualidade. São também apresentadas duas variantes da 1-boa iluminação: a iluminação ortogonal e a boa !-iluminação. Esta última tem aplicações em problemas de profundidade e visualização de dados, temas que são frequentemente abordados em estatística. A resolução destes problemas usando o diagrama de Voronoi Envolvente (uma variante do diagrama de Voronoi adaptada a problemas de boa iluminação) é também proposta nesta tese.
As the title implies, this thesis studies limited range coverage problems. Given a set of antennas (or any wireless device able to send or receive some sort of signal), the objective of the discussion that follows is to calculate the antennas’ minimum range so that a path between two points within a region is covered by the antennas, a path known as a safe route. The definition of coverage is variable and depends on the applications. In some instances, for example, when monitoring is critical as in the case of fires or military, the definition of coverage necessarily involves the use of multiple antennas to increase the effectiveness of monitoring. However, it is also desirable to extend a network’s lifespan, normally achieved by minimising the antennas’ range. Therefore the focus of this thesis will be the resolution of this dual problem and an affective solution is offered for each case. Although this question has been researched as an issue of coverage, it is also possible to establish a relation between coverage and illumination and visibility, known as Art Gallery problems. To conceptualise coverage problems as Art Gallery problems, all that is needed is to consider a set of lights instead of a set of antennas, which are subject to a similar set of restrictions. The main focus of the Art Gallery problems addressed in this thesis is 1-good illumination. An object is 1-well illuminated if it is fully contained by the convex hull of a set of lights, making this a type of quality illumination. The objective of the discussion that follows is therefore to minimise the lights’ range whilst maintaining a quality illumination. Moreover, two variants of 1-good illumination are also presented: orthogonal good illumination and good ! -illumination. The latter being related to data depth problems and data visualisation that are frequently used in statistics. The resolution of these problems using the Embracing Voronoi diagram (a variant of Voronoi diagrams adapted to good illumination) is also discussed in this thesis.
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Deshpande, Ajay A. "Coverage problems in mobile sensing". Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/46485.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2008.Includes bibliographical references (p. 177-183).
Sensor-networks can today measure physical phenomena at spatial and temporal scales that were not achievable earlier, and have shown promise in monitoring the environment, structures, agricultural fields and so on. A key challenge in sensor-networks is the coordination of four actions across the network: measurement (sensing), communication, motion and computation. The term coverage is applied to the central question of how well a sensor-network senses some phenomenon to make inferences. More formally, a coverage problem involves finding an arrangement of sensors that optimizes a coverage metric. In this thesis we examine coverage in the context of three sensing modalities. The literature on the topic has thus far focused largely on coverage problems with the first modality: static event-detection sensors, which detect purely binary events in their immediate vicinity based on thresholds. However, coverage problems for sensors which measure physical quantities like temperature, pressure, chemical concentrations, light intensity and so on in a network configuration have received limited attention in the literature. We refer to this second modality of sensors as estimation sensors; local estimates from such sensors can be used to reconstruct a field. Third, there has been recent interest in deploying sensors on mobile platforms. Mobility has the effect of increasing the effectiveness of sensing actions. We further classify sensor mobility into incidental and intentional motion. Incidentally mobile sensors move passively under the influence of the environment, for instance, a floating sensor drifting in the sea. We define intentional mobility as the ability to control the location and trajectory of the sensor, for example by mounting it on a mobile robot. We build our analysis on a series of cases. We first analyze coverage and connectivity of a network of floating sensors in rivers using simulations and experimental data, and give guidelines for sensor-network design. Second, we examine intentional mobility and detection sensors.
(cont.) We examine the problem of covering indoor and outdoor pathways with reconfigurable camera sensor-networks. We propose and validate an empirical model for detection behavior of cameras. We propose a distributed algorithm for reconfiguring locations of cameras to maximize detection performance. Finally, we examine more general strategies for the placement of estimation sensors and ask when and where to take samples in order to estimate an unknown spatiotemporal field with tolerable estimation errors. We discuss various classes of error-tolerant sensor arrangements for trigonometric polynomial fields.
by Ajay A. Deshpande.
Ph.D.
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Fajčík, Martin. "Automatizace verifikace pomocí neuronových sítí". Master's thesis, Vysoké učení technické v Brně. Fakulta informačních technologií, 2017. http://www.nusl.cz/ntk/nusl-363776.
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The goal of this thesis is to analyze and to find solutions of optimization problems derived from automation of functional verification of hardware using artificial neural networks. Verification of any integrated circuit (so called Design Under Verification, DUV) using technique called coverage-driven verification and universal verification methodology (UVM) is carried out by sending stimuli inputs into DUV. The verification environment continuously monitors percentual coverage of DUV functionality given by the specification. In current context, coverage stands for measurable property of DUV, like count of verified arithemtic operations or count of executed lines of code. Based on the final coverage, it is possible to determine whether the coverage of DUV is high enough to declare DUV as verified. Otherwise, the input stimuli set needs to change in order to achieve higher coverage. Current trend is to generate this set by technique called constrained-random stimulus generation. We will practice this technique by using pseudorandom program generator (PNG). In this paper, we propose multiple solutions for following two optimization problems. First problem is ongoing modification of PNG constraints in such a way that the DUV can be verified by generated stimuli as quickly as possible. Second one is the problem of seeking the smallest set of stimuli such that this set verifies DUV. The qualities of the proposed solutions are verified on 32-bit application-specific instruction set processors (ASIPs) called Codasip uRISC and Codix Cobalt.
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Matos, Daniel Ribeiro. "Um algoritmos distribuÃdo para escalonamento de sensores em RSSF". Universidade Federal do CearÃ, 2013. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=12187.
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nÃo hÃRedes de Sensores Sem Fio (RSSF) sÃo utilizadas em diversos tipos de aplicaÃÃes: desde casas inteligentes a aplicaÃÃes militares. RSSF possuem, em geral, severas restriÃÃes energÃticas - um sensor geralmente possui uma quantidade limitada de bateria e este nÃo à substituÃvel. Os sensores podem possuir uma certa redundÃncia de uma Ãrea sensoreada, uma vez que, quando os sensores sÃo distribuÃdos de forma aleatÃria, alguns sensores acabam ficando muito prÃximos, ou mesmo quando sÃo depositados de maneira determinÃstica, uma certa redundÃncia à necessÃria para prever a falha de alguns destes sensores. Neste trabalho, propomos um algoritmo distribuÃdo que faz um escalonamento de sensores ativos, de forma a reduzir a redundÃncia dos dados coletados e aumentar o tempo de vida da rede de sensores.
Wireless Sensor Networks (WSNs) are used in a lot of applications: from smart homes to military enviromnets. In general, WSNs has severe energy restrictions - a sensor usualy has a limited batery and itâs not replaceable. Distributing the sensor in a random mander can lead to a redundancy of some areas and this is desirable to support fail of some sensors. In this work, we propose an distributed algorithm to schedule active sensors to reduce the redundancy of data obtainned by the network and prolong the network lifetime.
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Michel, David. "All Negative on the Western Front: Analyzing the Sentiment of the Russian News Coverage of Sweden with Generic and Domain-Specific Multinomial Naive Bayes and Support Vector Machines Classifiers". Thesis, Uppsala universitet, Institutionen för lingvistik och filologi, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-447398.
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This thesis explores to what extent Multinomial Naive Bayes (MNB) and Support Vector Machines (SVM) classifiers can be used to determine the polarity of news, specifically the news coverage of Sweden by the Russian state-funded news outlets RT and Sputnik. Three experiments are conducted. In the first experiment, an MNB and an SVM classifier are trained with the Large Movie Review Dataset (Maas et al., 2011) with a varying number of samples to determine how training data size affects classifier performance. In the second experiment, the classifiers are trained with 300 positive, negative, and neutral news articles (Agarwal et al., 2019) and tested on 95 RT and Sputnik news articles about Sweden (Bengtsson, 2019) to determine if the domain specificity of the training data outweighs its limited size. In the third experiment, the movie-trained classifiers are put up against the domain-specific classifiers to determine if well-trained classifiers from another domain perform better than relatively untrained, domain-specific classifiers. Four different types of feature sets (unigrams, unigrams without stop words removal, bigrams, trigrams) were used in the experiments. Some of the model parameters (TF-IDF vs. feature count and SVM’s C parameter) were optimized with 10-fold cross-validation. Other than the superior performance of SVM, the results highlight the need for comprehensive and domain-specific training data when conducting machine learning tasks, as well as the benefits of feature engineering, and to a limited extent, the removal of stop words. Interestingly, the classifiers performed the best on the negative news articles, which made up most of the test set (and possibly of Russian news coverage of Sweden in general).
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Kaldé, Nassim. "Robotic Coverage and Exploration as Sequential Decision-Making Problems". Thesis, Université de Lorraine, 2017. http://www.theses.fr/2017LORR0276/document.
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Pouvoir se déplacer intelligemment dans un environnement inconnu est primordial pour des robots mobiles (Évitement d’Obstacle (EO)). Ceci est nécessaire pour explorer et construire une carte de l’environnement (CArtographie Active (CAA)), carte qui servira à d’autres tâches comme la patrouille (COuverture Active (COA)). Cette thèse se focalise sur la prise de décision pour planifier les déplacements de robots autonomes afin de naviguer, couvrir ou explorer l’environnement. Ainsi, nous nous basons sur la Prise de Décision Séquentielle (PDS) en Intelligence Artificielle et proposons deux contributions concernant : (1) les processus décisionnels de CAA et COA, et (2) la planification à long terme pour la COA. De plus, récemment, les robots mobiles ont commencé à partager l’espace physique avec les humains en fournissant des services comme du ménage à la maison. Dans ces cas, le comportement du robot doit s’adapter à la dynamique du monde. Par conséquent, nous proposons deux autres contributions pour : (3) la CAA en environnements de foule, et (4) l’EO par chemin clairsemé en environnements ambiantsThe ability to intelligently navigate in an unknown environment is essential for mobile robots (Obstacle Avoidance (OA)). This is needed to explore and build a map of the environment (Active Mapping (AM)); this map will then support other tasks such as patrolling (Active Coverage (AC)). In this thesis, we focus on decision-making to plan the moves of autonomous robots in order to navigate, cover, or explore the environment. Therefore, we rely on the framework of Sequential Decision-Making (SDM) in Artificial Intelligence to propose two contributions that address: (1) decision processes for AC and AM and (2) long-term planning for AC. Furthermore, mobile robots recently started sharing physical spaces with humans to provide services such as cleaning the house. In such cases, robot behavior should adapt to dynamic aspects of the world. In this thesis, we are interested in deploying autonomous robots in such environments. Therefore, we propose two other contributions that address: (3) short-term AM in crowded environments and (4) clearest path OA in ambient environments
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Matos, Daniel Ribeiro. "Um algoritmos distribuído para escalonamento de sensores em RSSF". reponame:Repositório Institucional da UFC, 2013. http://www.repositorio.ufc.br/handle/riufc/13353.
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MATOS, D. R. Um algoritmos distribuído para escalonamento de sensores em RSSF. 2013. 59 f. Dissertação (Mestrado em Ciência da Computação) - Centro de Ciências, Universidade Federal do Ceará, Fortaleza, 2013.Submitted by Daniel Eduardo Alencar da Silva (dealencar.silva@gmail.com) on 2015-01-23T18:29:56Z No. of bitstreams: 1 2013_dis_drmatos.pdf: 2537544 bytes, checksum: 870eae75ce068b1ef961e23307dda2a9 (MD5)
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Wireless Sensor Networks (WSNs) are used in a lot of applications: from smart homes to military enviromnets. In general, WSNs has severe energy restrictions - a sensor usualy has a limited batery and it’s not replaceable. Distributing the sensor in a random mander can lead to a redundancy of some areas and this is desirable to support fail of some sensors. In this work, we propose an distributed algorithm to schedule active sensors to reduce the redundancy of data obtainned by the network and prolong the network lifetime.
Redes de Sensores Sem Fio (RSSF) são utilizadas em diversos tipos de aplicações: desde casas inteligentes a aplicações militares. RSSF possuem, em geral, severas restrições energéticas - um sensor geralmente possui uma quantidade limitada de bateria e este não é substituível. Os sensores podem possuir uma certa redundância de uma área sensoreada, uma vez que, quando os sensores são distribuídos de forma aleatória, alguns sensores acabam ficando muito próximos, ou mesmo quando são depositados de maneira determinística, uma certa redundância é necessária para prever a falha de alguns destes sensores. Neste trabalho, propomos um algoritmo distribuído que faz um escalonamento de sensores ativos, de forma a reduzir a redundância dos dados coletados e aumentar o tempo de vida da rede de sensores.
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Yazdan, Panah Arian. "Nonuniform Coverage with Time-Varying Risk Density Function". Thesis, Université d'Ottawa / University of Ottawa, 2015. http://hdl.handle.net/10393/33007.
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Multi-agent systems are extensively used in several applications. An important class of applications involves the optimal spatial distribution of a group of mobile robots on a given area, where the optimality refers to the assignment of subregions to the robots, in such a way that a suitable coverage metric is maximized. Typically the coverage metric encodes a risk distribution defined on the area, and a measure of the performance of individual robots with respect to points inside the region of interest. The coverage metric will be maximized when the set of mobile robots configure themselves as the centroids of the Voronoi tessellation dictated by the risk density. In this work we advance on this result by considering a generalized area control problem in which the coverage metric is non-autonomous, that coverage metric is time varying independently of the states of the robots. This generalization is motivated by the study of coverage control problems in which the coordinated motion of a set of mobile robots accounts for the kinematics of objects penetrating from the outside. Asymptotic convergence and optimality of the non-autonmous system are studied by means of Barbalat's Lemma, and connections with the kinematics of the moving intruders is established. Several numerical simulation results are used to illustrate theoretical predictions.
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Badau, Estera-Tabita. "De la mise à l’épreuve de l’alimentation par l’antibiorésistance au développement des concepts sans antibiotique et One Health ˸ publicisation et communication en France et aux États-Unis". Thesis, Sorbonne Paris Cité, 2019. http://www.theses.fr/2019USPCA039.
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Dans une perspective comparative entre la France et les États-Unis, ce travail analyse le processus de publicisation des liens entre l’antibiorésistance et l’alimentation, ainsi que ses implications en termes de contribution au développement de la production appelée sans antibiotique et de l’approche One Health. En partant de la prise de conscience des conséquences de l’usage des antibiotiques dans l’élevage, la recherche s’inscrit dans une réflexion pragmatiste de constitution des problèmes publics et s’appuie sur un corpus hybride composé de documents publiés entre 1980 et 2016 (presse écrite, littérature institutionnelle et entretiens semi-directifs). La méthode développée s’enrichit des outils de textométrie issus de l’analyse de discours et s’intéresse à l’émergence des dénominations et des formules qui nomment le problème, ses causes et ses solutions. La comparaison montre que le processus de publicisation de liens entre l’antibiorésistance et l’alimentation dévoile une trajectoire opposée dans les deux pays. Dans le cas français, ce processus s’inscrit dans un schéma top-down et se caractérise par une publicisation tardive faisant suite aux démarches des instances sanitaires européennes et internationales. L’appropriation du problème par des associations de consommateurs, ainsi que l’investissement des acteurs agroalimentaires dans le développement de la production sans antibiotique, n’émergent que récemment. En revanche, aux États-Unis, ce processus s’inscrit dans un modèle bottom-up suite à la constitution d’un public d’organisations non gouvernementales autour du problème. Leur mobilisation a contribué significativement au développement de programmes d’élevage sans antibiotique ainsi qu’à la mise à l’agenda gouvernemental du problème et le lancement d’un plan national dans une approche One HealthIn a cross-country perspective between France and the United States, this research analyses the process of publicizing the links between antibiotic resistance and food, as well as its contribution to the development of the antibiotic free production and the implementation of the One Health approach. Starting with the awareness of the antibiotic use in livestock consequences, the study relies on the pragmatist approach of the constitution of the public problems. It is based on wide corpora composed by documents published between 1980 and 2016 (written press, institutional literature and semi-directive interviews). The analysis method uses textometric tools derived from discourse analysis and focuses on the emergence of formulas that name the problem, its causes and its solutions. The comparison uncovers an opposite process between the two countries. In France, this process is part of a top-down approach and is characterized by a late publicization following the European and international health authorities’ initiatives. The consumer associations taking over the problem, as well as the agri-food actors’ commitment to the antibiotic free production, is very recent. In the United States, this process reveals a bottom-up model following a non-governmental organizations public constitution taking over the problem. Their mobilization has contributed to the development of the antibiotic free breeding programs, as well as to place the problem on the government agenda that launched a national plan in a One Health approach
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Mohammad, Hossein Fallah Mostafa. "Coordinated Deployment of Multiple Autonomous Agents in Area Coverage Problems with Evolving Risk". Thesis, Université d'Ottawa / University of Ottawa, 2015. http://hdl.handle.net/10393/33164.
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Coordinated missions with platoons of autonomous agents are rapidly becoming popular because of technological advances in computing, networking, miniaturization and combination of electromechanical systems. These multi-agents networks coordinate their actions to perform challenging spatially-distributed tasks such as search, survey, exploration, and mapping. Environmental monitoring and locational optimization are among the main applications of the emerging technology of wireless sensor networks where the optimality refers to the assignment of sub-regions to each agent, in such a way that a suitable coverage metric is maximized. Usually the coverage metric encodes a distribution of risk defined on the area, and a measure of the performance of individual robots with respect to points inside the region of interest. The risk density can be used to quantify spatial distributions of risk in the domain.
The solution of the optimal control problem in which the risk measure is not time varying is well known in the literature, with the optimal con figuration of the robots given by the centroids of the Voronoi regions forming a centroidal Voronoi tessellation of the area. In other words, when the set of mobile robots converge to the corresponding centroids of the Voronoi tessellation dictated by the coverage metric, the coverage itself is maximized.
In this work, it is considered a time-varying risk density evolving according to a diffusion equation with varying boundary conditions that quantify a time-varying risk on the border of the workspace. Boundary conditions model a time varying flux of external threats coming into the area, averaged over the boundary length, so that rather than considering individual kinematics of incoming threats it is considered an averaged, distributed effect. This approach is similar to the one commonly adopted in continuum physics, in which kinematic descriptors are averaged over spatial domain and suitable continuum fields are introduced to describe their evolution. By adopting a first gradient constitutive relation between the flux and the density, a simple diffusion equation is obtained. Asymptotic convergence and optimality of the non-autonomous system are studied by means of Barbalat's lemma and connections with varying boundary conditions are established. Some criteria on time-varying boundary conditions and evolution are established to guarantee
the stabilities of agents' trajectories. A set of numerical simulations illustrate theoretical results.
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Eno, Daniel R. "Noninformative Prior Bayesian Analysis for Statistical Calibration Problems". Diss., Virginia Tech, 1999. http://hdl.handle.net/10919/27140.
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In simple linear regression, it is assumed that two variables are linearly related, with unknown intercept and slope parameters. In particular, a regressor variable is assumed to be precisely measurable, and a response is assumed to be a random variable whose mean depends on the regressor via a linear function. For the simple linear regression problem, interest typically centers on estimation of the unknown model parameters, and perhaps application of the resulting estimated linear relationship to make predictions about future response values corresponding to given regressor values. The linear statistical calibration problem (or, more precisely, the absolute linear calibration problem), bears a resemblance to simple linear regression. It is still assumed that the two variables are linearly related, with unknown intercept and slope parameters. However, in calibration, interest centers on estimating an unknown value of the regressor, corresponding to an observed value of the response variable.
We consider Bayesian methods of analysis for the linear statistical calibration problem, based on noninformative priors. Posterior analyses are assessed and compared with classical inference procedures. It is shown that noninformative prior Bayesian analysis is a strong competitor, yielding posterior inferences that can, in many cases, be correctly interpreted in a frequentist context.
We also consider extensions of the linear statistical calibration problem to polynomial models and multivariate regression models. For these models, noninformative priors are developed, and posterior inferences are derived. The results are illustrated with analyses of published data sets. In addition, a certain type of heteroscedasticity is considered, which relaxes the traditional assumptions made in the analysis of a statistical calibration problem. It is shown that the resulting analysis can yield more reliable results than an analysis of the
homoscedastic model.Ph. D.
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Ouedraogo, Lisa-Marie [Verfasser]. "Approaching Universal Health Coverage in Kenya : the Potential of integrating Community Based Health Insurance Schemes / Lisa-Marie Ouedraogo". Greifswald : Universitätsbibliothek Greifswald, 2017. http://d-nb.info/1129900789/34.
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de, Menil Victoria. "Under-cover in Kenya : the contribution of non-state actors to mental health coverage". Thesis, London School of Economics and Political Science (University of London), 2014. http://etheses.lse.ac.uk/1017/.
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Half of health care in sub-Saharan Africa is privately provided, however, for mental health, the literature is all but absent on these services. Kenya provides a useful case-study, as it has a wellorganized non-state sector and data are readily available. My thesis asks what contribution do non-state actors make to coverage for mental disorders in Kenya? Non-state mental health care is conceived along two axes: for-profit vs. not-for-profit and formal vs. informal. Four empirical chapters use mixed-methods to examine: 1) not-forprofit NGO care; 2) for-profit inpatient care; 3) for-profit outpatient care; and 4) traditional and faith healing. Data were collected on 774 service users and 120 service providers from four primary sources, and two secondary sources, as well as from a wide range of key-informant interviews. The first two chapters set the research question within the context of existing knowledge in the fields of health economics and health services research. The third chapter provides an overview of methods, focusing on cost-effectiveness analysis, case study method, and crosscultural psychiatric epidemiology. The first empirical chapter presents an NGO intervention called the model for Mental Health and Development, evaluated qualitatively and quantitatively, using cost-effectiveness analysis. The second empirical chapter offers a case study of a growing private psychiatric hospital, using regression analysis on the effects of insurance on charge and service use. The third chapter is a short descriptive analysis of a questionnaire completed by psychiatric nurses about their participation in mental health care, and structured interviews with specialist outpatient providers. The final empirical chapter contains qualitative and quantitative data on traditional and faith healing, analysed for similarities and differences. The conclusion ties together findings thematically according to capacity, access and cost, estimating the degree of mental health care coverage offered by non-state actors in Kenya, and offering lessons for policy and research.
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Vieira, Deborah Luisa Detânico. "Planejamento da cobertura de redes móveis de quarta geração através de metaheurística híbrida". Universidade do Vale do Rio dos Sinos, 2017. http://www.repositorio.jesuita.org.br/handle/UNISINOS/6994.
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Com a crescente demanda de serviços de voz e, principalmente, dados móveis se fez necessário o desenvolvimento das tecnologias de quarta geração (4G). O padrão Long Term Evolution (LTE), desenvolvido pela Third Generation Partnership Project (3GPP), foi escolhido pela International Telecommunications Union (ITU) como tecnologia para atender os requisitos da quarta geração de serviços móveis. Para as operadoras inserirem esta nova tecnologia em suas redes existentes, se faz necessário um estudo meticuloso de planejamento, muito embora, na prática, este planejamento seja desenvolvido de forma empírica. O problema de planejamento de redes é conhecido e bem estudado no ramo da computação, conhecido como problema de recobrimento de conjuntos e classificado, pela sua complexidade, como NP-difícil. Dadas as características diferenciadas da arquitetura da rede do LTE, este trabalho busca resolver o problema de planejamento de redes de quarta geração (4G), utilizando uma modelagem matemática aplicada a uma metaheurística híbrida, composta de Algoritmo Genético e Busca Tabu. Almejase resolver o problema de cobertura de uma determinada região, cobrindo a maior área possível com o menor número possível de Base Stations (BS), visando ao planejamento com maior assertividade e redução do custo de implantação da rede 4G.
With the constantly demand of voice services and mostly in mobile data, there was the need the development of the mobile services of fourth generation (4G). The pattern Long Term Evolution, developed by the Third Generation Partnership Project (3GPP) was chosen by the International Telecommunications Union (ITU) as technology to attend the requirements of the fourth generation of mobile services. For the mobile operators introduce and apply this new generation in their own existing networks, they need to do an extensive research and planning, even if, in practical means, it is applied using the empirical way. The network planning problem is widely known and studied in computing area as set-covering problem ans classified as NPhard. Due the unique characteristics of network architecture of LTE, this work aims to solve the mobile’s fourth generation planning problem using a mathematics modelling apply to a hybrid metaheuristics, composed with Genetic Algorithm and Tabu Search. It aims solve the coverage problem of a specific region, covering the largest area possible with the fewest number of Base Sations (BS) possible, seeking the best compliance and cost reduction of the LTE network deployment.
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Göppel, Christine [Verfasser]. "Universal and equitable health coverage for adults aged 50 years or older with chronic illness in middle income countries / Christine Göppel". Berlin : Medizinische Fakultät Charité - Universitätsmedizin Berlin, 2017. http://d-nb.info/1133074596/34.
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Watanabe, Kohei. "Measuring bias in international news : a large-scale analysis of news agency coverage of the Ukraine crisis". Thesis, London School of Economics and Political Science (University of London), 2017. http://etheses.lse.ac.uk/3658/.
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I present a new methodological approach to measuring news bias, aiming to settle the disagreement on how to define and measure bias in media and communication studies in this thesis. Unlike earlier research on TV news or newspapers, I choose international news agencies’ coverage of the Ukraine crisis in this study as a case to highlight the strength of the new approach. Utilizing newly-developed geographical news classification and sentiment analysis techniques, I analyse news coverage of the Ukraine crisis by Russia’s official news agency, ITAR-TASS, along with the independent news agency, Interfax, over two years to estimate partisan news bias resulting from stateownership. In this longitudinal content analysis, I focus on the change in sentiment of ITAR-TASS’s news coverage of Ukraine relative to Interfax’s coverage during periods following six key events in the crisis. The analysis shows that the sentiment of ITAR-TASS’s news on Ukraine’s democracy and sovereignty changed significantly after key events, reflecting the desirability of these events to the Russian government. ITAR-TASS’s news coverage became the most negative when the new Ukraine government launched military operations against pro-Russian separatists in east Ukraine, claiming that the revolution was instigated by Ukrainian fascists, who threatened the safety of ethnic Russians. This result indicates that the Russian government utilized the news agency for international propaganda to justify its actions. Further, an additional content analysis including western news agencies revealed that Reuters’s news coverage of the Ukraine crisis during this period was strongly correlated with ITAR-TASS, being influenced by the Russian government’s false statements on Ukraine. Reuters news stories were circulated internationally, and published in the most popular news sites in the United States without context. I argue that the publication of the Russian government’s false narratives by American online news sites through Reuters indicates the vulnerability of today’s international news gathering and distribution system, and the rapidly changing relationship between states and corporations in the global news industry. This suggests that western news agencies’ use of temporary correspondents in covering rapidly developing international crises increases the risk of spreading false information globally. In this case, western news agencies are, in effect, supporting international propaganda by non-western states.
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Zu, Guo. "Framing Pollution: An Analysis of the Coverage of Air Pollution in China in 2013 by ChinaDaily.com". Ohio University / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1429698709.
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Gallmann, Elena. "A critical appraisal of coverage and resource allocation decisions through the use of health technology assessment : evidence on orphan drugs from four countries". Thesis, London School of Economics and Political Science (University of London), 2015. http://etheses.lse.ac.uk/3433/.
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Health Technology Assessment (HTA) relies on evidence-based medicine to inform drug coverage recommendations about the most efficient use of resources. Despite appraising the same evidence based on similar methodological approaches, HTA recommendations for the same drug differ across countries. This thesis aimed to understand the reasons for these differences, and based on cross-national comparisons, whether they are a consequence of methodological challenges in HTA. A mixed methods research design was used to develop a methodological framework that allows to breakdown these complex processes in a comparable and understandable manner, by considering: (a) the evidence appraised, (b) its interpretation, and (c) how this influenced the final decision. Ten orphan drug-indication pairs appraised in four countries (England, Scotland, Sweden and France (N=35)) were systematically analysed and compared on this basis. Results present the criteria accounted for at each stage of the process in the decisions, the reasons for differences across countries, and how HTA bodies are dealing with issues relating to orphan drugs. Quantitative analysis of these provided information about agency-specific risk and value preferences, and measured agreement in interpreting the same evidence. There was heterogeneity within and across countries in the criteria accounted for and reasons for cross-country differences. Interviews to competent authorities provided insights about these differences and implications for HTA. Although agreement was seen in the evidentiary requirements or preferences, there were subtle differences in the circumstances where uncertain evidence may be considered acceptable, partly explaining diverging HTA recommendations. The three main contributions of this thesis are: (1) the development of a methodological framework to understand what criteria feed into HTAs, which can be applied to other drugs and countries; (2) through its application, the identification of a full taxonomy of criteria considered in decisionmaking; and (3) the ability to understand the differences in HTA recommendations across countries. A better understanding of HTA in different settings may help advance these processes, and, ultimately, improve access to treatments.
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Mueller, John Frederick. "An analysis of the correspondence of environmental coverage in Ohio's six major metropolitan newspapers to citizen perception of environmental problems". Ohio : Ohio University, 2006. http://www.ohiolink.edu/etd/view.cgi?ohiou1145420206.
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Mueller, John F. "An Analysis of the Correspondence of Environmental Coverage in Ohio's Six Major Metropolitan Newspapers to Citizen Perception of Environmental Problems". Ohio University / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1145420206.
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Cottle, Simon. "Television coverage of the inner city : an examination of the professional journalist's practices and production domain and their impact upon the public portrayal of the problems and issues of the inner city". Thesis, University of Leicester, 1990. http://hdl.handle.net/2381/34622.
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This thesis examines the portrayal of the problems and issues of the inner city by an Independent Television Company across its factual programming over an eight year period from 1982 to 1989. Following a critical review of existing mass communications' literature an intermediate level of analysis and theorisation is secured which, recognising the explanatory contributions won by competing approaches, nonetheless identifies a significant theoretical lacuna in their midst. This concerns the deliberate pursuit of established programme forms by professional journalists and programme makers and which are reproduced as a 'known result*. The portrayal of the inner city is examined in terms of substantive content, access, forum and means of communication at both 'reading' and 'production' stages of empirical analysis. Essentially the study attends to the interpretative 'resources and accounts' found within this inner city portrayal and placed within the public domain as well as the characteristic, and impacting properties of the medium'. Following an extensive 'reading', including an examination of the characteristic forms, subject interests and relational appeals of established programmes genres, as well as substantive inner city news and riot coverage across different factual programmes and employing a variety of quantitative and qualitative reading methods, the study turns to an examination of professional practices within the production and institutional domains. Participant observation, semi~structured interviews and a number of in-depth case studies are used to complement the findings elicited at the 'reading' stage. Professional practices are examined to the extent that they enact and reproduce on a daily basis established interests and properties of the regional news programme. Finally the thesis situates the analysis within the wider and changing institutional context already found to impact upon the limited and characteristic forms of inner city portrayal.
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Tong, Daoqin. "Continuous space facility location for covering spatial demand objects". Columbus, Ohio : Ohio State University, 2007. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1186686117.
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Nguyen, Ngo Minh Thang. "Test case generation for Symbolic Distributed System Models : Application to Trickle based IoT Protocol". Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLC092.
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Les systèmes distribués sont composés de nombreux sous-systèmes distants les uns des autres. Afin de réaliser une même tâche, les sous-systèmes communiquent à la fois avec l’environnement par des messages externes et avec d’autres sous-systèmes par des messages internes, via un réseau de communication. En pratique, les systèmes distribués mettent en jeu plusieurs types d’erreurs, propres aux sous-systèmes les constituant, ou en lien avec les communications internes. Afin de s’assurer de leur bon fonctionnement, savoir tester de tels systèmes est essentiel. Cependant, il est très compliqué de les tester car sans horloge globale, les sous-systèmes ne peuvent pas facilement synchroniser leurs envois de messages, ce qui explique l’existence des situations non déterministes. Le test à base de modèles (MBT) est une approche qui consiste à vérifier si le comportement d’un système sous test (SUT) est conforme à son modèle, qui spécifie les comportements souhaités. MBT comprend deux étapes principales: la génération de cas de test et le calcul de verdict. Dans cette thèse, nous nous intéressons à la génération de cas de test dans les systèmes distribués. Nous utilisons les systèmes de transition symbolique temporisé à entrées et sorties (TIOSTS) et les analysons à l’aide des techniques d’exécution symbolique pour obtenir les comportements symboliques du système distribué. Dans notre approche, l’architecture de test permet d’observer au niveau de chaque soussystème à la fois les messages externes émis vers l’environnement et les messages internes reçus et envoyés. Notre framework de test comprend plusieurs étapes: sélectionner un objectif de test global, défini comme un comportement particulier exhibé par exécution symbolique, projeter l’objectif de test global sur chaque sous-système pour obtenir des objectifs de test locaux, dériver des cas de test unitaires pour chacun des sous-systèmes. L’exécution du test consiste à exécuter des cas de test locaux sur les sous-systèmes paramétrés par les objectifs de tests en calculant à la volée les données de test à soumettre au sous-système en fonction de données observées. Enfin, nous mettons en œuvre notre approche sur un cas d’étude décrivant un protocole utilisé dans le contexte de l’IoTDistributed systems are composed of many distant subsystems. In order to achieve a common task, subsystems communicate both with the local environment by external messages and with other subsystems by internal messages through a communication network. In practice, distributed systems are likely to reveal many kinds of errors, so that we need to test them before reaching a certain level of confidence in them. However, testing distributed systems is complicated due to their intrinsic characteristics. Without global clocks, subsystems cannot synchronize messages, leading to non-deterministic situations.Model-Based Testing (MBT) aims at checking whether the behavior of a system under test (SUT) is consistent with its model, specifying expected behaviors. MBT is useful for two main steps: test case generation and verdict computation. In this thesis, we are mainly interested in the generation of test cases for distributed systems.To specify the desired behaviors, we use Timed Input Output Symbolic Transition Systems (TIOSTS), provided with symbolic execution techniques to derive behaviors of the distributed system. Moreover, we assume that in addition to external messages, a local test case observes internal messages received and sent by the co-localized subsystem. Our testing framework includes several steps: selecting a global test purpose using symbolic execution on the global system, projecting the global test purpose to obtain a local test purpose per subsystem, deriving unitary test case per subsystem. Then, test execution consists of executing local test cases by submitting data compatible following a local test purpose and computing a test verdict on the fly. Finally, we apply our testing framework to a case study issued from a protocol popular in the context of IoT
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Kao, Jen-Hung, i 高仁宏. "The Distribution Coverage Problem". Thesis, 2003. http://ndltd.ncl.edu.tw/handle/mf9g8e.
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碩士中原大學
數學研究所
91
In natural, many things have rich mathematical structure. In this thesis, a possible method for constructing structures of natural is described. We first give the definition of distribution coverage, and our main topic: the ideal distribution coverage problem. These problems is trying to find the maximum volume when a distribution D is given. We provide proofs when |D| = 2,3, 4, and other results additionally. We also develop a algorithm, which performs for finding the coordinates of a distribution D.
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Yang, Lan-Chih, i 楊蘭智. "Sensor Deployment Algorithm for k-Angle Coverage Problem". Thesis, 2009. http://ndltd.ncl.edu.tw/handle/97375955554304512259.
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碩士國立清華大學
資訊工程學系
97
Coverage problem is one of the most fundamental problems in wireless sensor networks since it reflects the sensing quality of a sensor network. Several coverage problems have been studied for different applications such as [1], [2] studies the coverage problem, and [12] discussed the barrier coverage problems. However, these works assume the sensor has Omni-directional sensing model which is not suitable in many applications such as video surveillance systems consisting of directional video sensors. In this thesis, we study a new coverage problem in wireless sensor networks. The k-angle coverage problem considers the problem using directional sensors which can only cover a limited angle and range. Given a set of targets to be monitored, the goal is to deploy minimal number of sensors to k-angle cover all the targets. We present a greedy algorithm to solve this problem. For this algorithm, we define three contribution functions to determine the location to deploy sensor. The proposed method greedily selects a maximal contribution location to deploy a sensor until the entire targets are k-angle covered. Simulation results exhibit the characteristic and performance of our algorithm. Based on the proposed algorithm, we develop a toolkit for emulating sensor deployment.