700 research outputs found

    Opportunistic data collection and routing in segmented wireless sensor networks

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    La surveillance reĢgulieĢ€re des opeĢrations dans les aires de manoeuvre (voies de circulation et pistes) et aires de stationnement d'un aeĢroport est une taĢ‚che cruciale pour son fonctionnement. Les strateĢgies utiliseĢes aĢ€ cette fin visent Ć  permettre la mesure des variables environnementales, l'identification des deĢbris (FOD) et l'enregistrement des statistiques d'utilisation de diverses sections de la surface. Selon un groupe de gestionnaires et controĢ‚leurs d'aeĢroport interrogeĢs, cette surveillance est un privileĢ€ge des grands aeĢroports en raison des couĢ‚ts eĢleveĢs d'acquisition, d'installation et de maintenance des technologies existantes. Les moyens et petits aeĢroports se limitent gĆ©nĆ©ralement aĢ€ la surveillance de quelques variables environnementales et des FOD effectueĢe visuellement par l'homme. Cette dernieĢ€re activiteĢ impose l'arreĢ‚t du fonctionnement des pistes pendant l'inspection. Dans cette theĢ€se, nous proposons une solution alternative baseĢe sur les reĢseaux de capteurs sans fil (WSN) qui, contrairement aux autres meĢthodes, combinent les proprieĢteĢs de faible couĢ‚t d'installation et maintenance, de dĆ©ploiement rapide, d'eĢvolutiviteĢ tout en permettant d'effectuer des mesures sans interfeĢrer avec le fonctionnement de l'aeĢroport. En raison de la superficie d'un aeĢroport et de la difficulteĢ de placer des capteurs sur des zones de transit, le WSN se composerait d'une collection de sous-reĢseaux isoleĢs les uns des autres et du puits. Pour gĆ©rer cette segmentation, notre proposition s'appuie sur l'utilisation opportuniste des vĆ©hicules circulants dans l'aĆ©roport considĆ©rĆ©s alors comme un type speĢcial de nœud appeleĢ Mobile Ubiquitous LAN Extension (MULE) chargĆ© de collecter les donneĢes des sous-reĢseaux le long de son trajet et de les transfeĢrer vers le puits. L'une des exigences pour le deĢploiement d'un nouveau systeĢ€me dans un aeĢroport est qu'il cause peu ou pas d'interruption des opeĢrations reĢgulieĢ€res. C'est pourquoi l'utilisation d'une approche opportuniste basĆ© sur des MULE est privileĢgieĢe dans cette theĢ€se. Par opportuniste, nous nous reĢfeĢrons au fait que le roĢ‚le de MULE est joueĢ par certains des veĢhicules deĢjaĢ€ existants dans un aeĢroport et effectuant leurs deĢplacements normaux. Et certains nœuds des sous- reĢseaux exploiteront tout moment de contact avec eux pour leur transmettre les donneĢes Ć  transfĆ©rer ensuite au puits. Une caracteĢristique des MULEs dans notre application est qu'elles ont des trajectoires structureĢes (suivant les voies de circulation dans l'aeĢroport), en ayant eĢventuellement un contact avec l'ensemble des nœuds situeĢs le long de leur trajet (appeleĢs sous-puits). Ceci implique la neĢcessiteĢ de dĆ©finir une strateĢgie de routage dans chaque sous-reĢseau, capable d'acheminer les donneĢes collecteĢes des nœuds vers les sous-puits et de reĢpartir les paquets de donneĢes entre eux afin que le temps en contact avec la MULE soit utiliseĢ le plus efficacement possible. Dans cette theĢ€se, nous proposons un protocole de routage remplissant ces fonctions. Le protocole proposeĢ est nommeĢ ACME (ACO-based routing protocol for MULE-assisted WSNs). Il est baseĢ sur la technique d'Optimisation par Colonies de Fourmis. ACME permet d'assigner des nœuds aĢ€ des sous-puits puis de dĆ©finir les chemins entre eux, en tenant compte de la minimisation de la somme des longueurs de ces chemins, de l'Ć©quilibrage de la quantitĆ© de paquets stockĆ©s par les sous-puits et du nombre total de retransmissions. Le probleĢ€me est deĢfini comme une taĢ‚che d'optimisation multi-objectif qui est reĢsolue de manieĢ€re distribueĢe sur la base des actions des nœuds dans un scheĢma collaboratif. Nous avons dĆ©veloppĆ© un environnement de simulation et effectueĢ des campagnes de calculs dans OMNeT++ qui montrent les avantages de notre protocole en termes de performances et sa capaciteĢ aĢ€ s'adapter aĢ€ une grande varieĢteĢ de topologies de reĢseaux.The regular monitoring of operations in both movement areas (taxiways and runways) and non-movement areas (aprons and aircraft parking spots) of an airport, is a critical task for its functioning. The set of strategies used for this purpose include the measurement of environmental variables, the identification of foreign object debris (FOD), and the record of statistics of usage for diverse sections of the surface. According to a group of airport managers and controllers interviewed by us, the wide monitoring of most of these variables is a privilege of big airports due to the high acquisition, installation and maintenance costs of most common technologies. Due to this limitation, smaller airports often limit themselves to the monitoring of environmental variables at some few spatial points and the tracking of FOD performed by humans. This last activity requires stopping the functioning of the runways while the inspection is conducted. In this thesis, we propose an alternative solution based on Wireless Sensor Network (WSN) which, unlike the other methods/technologies, combines the desirable properties of low installation and maintenance cost, scalability and ability to perform measurements without interfering with the regular functioning of the airport. Due to the large extension of an airport and the difficulty of placing sensors over transit areas, the WSN might result segmented into a collection of subnetworks isolated from each other and from the sink. To overcome this problem, our proposal relies on a special type of node called Mobile Ubiquitous LAN Extension (MULE), able to move over the airport surface, gather data from the subnetworks along its way and eventually transfer it to the sink. One of the main demands for the deployment of any new system in an airport is that it must have little or no interference with the regular operations. This is why the use of an opportunistic approach for the transfer of data from the subnetworks to the MULE is favored in this thesis. By opportunistic we mean that the role of MULE will be played by some of the typical vehicles already existing in an airport doing their normal displacements, and the subnetworks will exploit any moment of contact with them to forward data to the sink. A particular characteristic of the MULEs in our application is that they move along predefined structured trajectories (given by the layout of the airport), having eventual contact with the set of nodes located by the side of the road (so-called subsinks). This implies the need for a data routing strategy to be used within each subnetwork, able to lead the collected data from the sensor nodes to the subsinks and distribute the data packets among them so that the time in contact with the MULE is used as efficiently as possible. In this thesis, we propose a routing protocol which undertakes this task. Our proposed protocol is named ACME, standing for ACO-based routing protocol for MULE-assisted WSNs. It is founded on the well known Ant Colony Optimization (ACO) technique. The main advantage of ACO is its natural fit to the decentralized nature of WSN, which allows it to perform distributed optimizations (based on local interactions) leading to remarkable overall network performance. ACME is able to assign sensor nodes to subsinks and generate the corresponding multi-hop paths while accounting for the minimization of the total path length, the total subsink imbalance and the total number of retransmissions. The problem is defined as a multi-objective optimization task which is resolved in a distributed manner based on actions of the sensor nodes acting in a collaborative scheme. We conduct a set of computational experiments in the discrete event simulator OMNeT++ which shows the advantages of our protocol in terms of performance and its ability to adapt to a variety of network topologie

    Bio-inspired multi-agent systems for reconfigurable manufacturing systems

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    The current marketā€™s demand for customization and responsiveness is a major challenge for producing intelligent, adaptive manufacturing systems. The Multi-Agent System (MAS) paradigm offers an alternative way to design this kind of system based on decentralized control using distributed, autonomous agents, thus replacing the traditional centralized control approach. The MAS solutions provide modularity, flexibility and robustness, thus addressing the responsiveness property, but usually do not consider true adaptation and re-configuration. Understanding how, in nature, complex things are performed in a simple and effective way allows us to mimic natureā€™s insights and develop powerful adaptive systems that able to evolve, thus dealing with the current challenges imposed on manufactur- ing systems. The paper provides an overview of some of the principles found in nature and biology and analyses the effectiveness of bio-inspired methods, which are used to enhance multi-agent systems to solve complex engineering problems, especially in the manufacturing field. An industrial automation case study is used to illustrate a bio-inspired method based on potential fields to dynamically route pallets

    Routing algorithm for the ground team in transmission line inspection using unmanned aerial vehicle

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    With the rapid development of robotics technology, robots are increasingly used to conduct various tasks by utility companies. An unmanned aerial vehicle (UAV) is an efficient robot that can be used to inspect high-voltage transmission lines. UAVs need to stay within a data transmission range from the ground station and periodically land to replace the battery in order to ensure that the power system can support its operation. A routing algorithm must be used in order to guide the motion and deployment of the ground station while using UAV in transmission line inspection. Most existing routing algorithms are dedicated to pathfinding for a single object that needs to travel from a given start point to end point and cannot be directly used for guiding the ground station deployment and motion since multiple objects (i.e., the UAV and the ground team) whose motions and locations need to be coordinated are involved. In this thesis, we intend to explore the routing algorithm that can be used by utility companies to effectively utilize UAVs in transmission line inspection. Both heuristic and analytical algorithms are proposed to guide the deployment of the ground station and the landing point for UAV power system change. A case study was conducted to validate the effectiveness of the proposed routing algorithm and examine the performance and cost-effectiveness --Abstract, page iii

    Optimasi Capacitated Vehicle Routing Problem with Time Windows dengan Menggunakan Ant Colony Optimization

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    In recent years, minimization of logistics and transportation costs has become essential for manufacturing companies to increase profits. One thing is done to reduce logistics and transportation costs by optimizing the route of taking or transporting components from each supplier. Route optimization to minimize total transportation costs is a problem that often finds in Vehicle Routing Problems (VRP). Problem Capacitated Vehicle Routing with Time Windows (CVRPTW) is one variant of VRP that considers the vehicle capacity and the service period of each vehicle. CVRPTW is a Non-Polynomial Hard (NP-Hard) problem that requires an efficient and effective algorithm in solving problems that occur in this automotive company. This study uses the Ant Colony Optimization (ACO) algorithm by testing using several parameters to solve the CVRPTW problem. The test results using the ACO algorithm obtained a faster route compared to the method applied by the company

    Optimum Allocation of Inspection Stations in Multistage Manufacturing Processes by Using Max-Min Ant System

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    In multistage manufacturing processes it is common to locate inspection stations after some or all of the processing workstations. The purpose of the inspection is to reduce the total manufacturing cost, resulted from unidentified defective items being processed unnecessarily through subsequent manufacturing operations. This total cost is the sum of the costs of production, inspection and failures (during production and after shipment). Introducing inspection stations into a serial multistage manufacturing process, although constituting an additional cost, is expected to be a profitable course of action. Specifically, at some positions the associated inspection costs will be recovered from the benefits realised through the detection of defective items, before wasting additional cost by continuing to process them. In this research, a novel general cost modelling for allocating a limited number of inspection stations in serial multistage manufacturing processes is formulated. In allocation of inspection station (AOIS) problem, as the number of workstations increases, the number of inspection station allocation possibilities increases exponentially. To identify the appropriate approach for the AOIS problem, different optimisation methods are investigated. The MAX-MIN Ant System (MMAS) algorithm is proposed as a novel approach to explore AOIS in serial multistage manufacturing processes. MMAS is an ant colony optimisation algorithm that was designed originally to begin an explorative search phase and, subsequently, to make a slow transition to the intensive exploitation of the best solutions found during the search, by allowing only one ant to update the pheromone trails. Two novel heuristics information for the MMAS algorithm are created. The heuristic information for the MMAS algorithm is exploited as a novel means to guide ants to build reasonably good solutions from the very beginning of the search. To improve the performance of the MMAS algorithm, six local search methods which are well-known and suitable for the AOIS problem are used. Selecting relevant parameter values for the MMAS algorithm can have a great impact on the algorithmā€™s performance. As a result, a method for tuning the most influential parameter values for the MMAS algorithm is developed. The contribution of this research is, for the first time, a methodology using MMAS to solve the AOIS problem in serial multistage manufacturing processes has been developed. The methodology takes into account the constraints on inspection resources, in terms of a limited number of inspection stations. As a result, the total manufacturing cost of a product can be reduced, while maintaining the quality of the product. Four numerical experiments are conducted to assess the MMAS algorithm for the AOIS problem. The performance of the MMAS algorithm is compared with a number of other methods this includes the complete enumeration method (CEM), rule of thumb, a pure random search algorithm, particle swarm optimisation, simulated annealing and genetic algorithm. The experimental results show that the effectiveness of the MMAS algorithm lies in its considerably shorter execution time and robustness. Further, in certain conditions results obtained by the MMAS algorithm are identical to the CEM. In addition, the results show that applying local search to the MMAS algorithm has significantly improved the performance of the algorithm. Also the results demonstrate that it is essential to use heuristic information with the MMAS algorithm for the AOIS problem, in order to obtain a high quality solution. It was found that the main parameters of MMAS include the pheromone trail intensity, heuristic information and evaporation of pheromone are less sensitive within the specified range as the number of workstations is significantly increased

    IoT in smart communities, technologies and applications.

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    Internet of Things is a system that integrates different devices and technologies, removing the necessity of human intervention. This enables the capacity of having smart (or smarter) cities around the world. By hosting different technologies and allowing interactions between them, the internet of things has spearheaded the development of smart city systems for sustainable living, increased comfort and productivity for citizens. The Internet of Things (IoT) for Smart Cities has many different domains and draws upon various underlying systems for its operation, in this work, we provide a holistic coverage of the Internet of Things in Smart Cities by discussing the fundamental components that make up the IoT Smart City landscape, the technologies that enable these domains to exist, the most prevalent practices and techniques which are used in these domains as well as the challenges that deployment of IoT systems for smart cities encounter and which need to be addressed for ubiquitous use of smart city applications. It also presents a coverage of optimization methods and applications from a smart city perspective enabled by the Internet of Things. Towards this end, a mapping is provided for the most encountered applications of computational optimization within IoT smart cities for five popular optimization methods, ant colony optimization, genetic algorithm, particle swarm optimization, artificial bee colony optimization and differential evolution. For each application identified, the algorithms used, objectives considered, the nature of the formulation and constraints taken in to account have been specified and discussed. Lastly, the data setup used by each covered work is also mentioned and directions for future work have been identified. Within the smart health domain of IoT smart cities, human activity recognition has been a key study topic in the development of cyber physical systems and assisted living applications. In particular, inertial sensor based systems have become increasingly popular because they do not restrict usersā€™ movement and are also relatively simple to implement compared to other approaches. Fall detection is one of the most important tasks in human activity recognition. With an increasingly aging world population and an inclination by the elderly to live alone, the need to incorporate dependable fall detection schemes in smart devices such as phones, watches has gained momentum. Therefore, differentiating between falls and activities of daily living (ADLs) has been the focus of researchers in recent years with very good results. However, one aspect within fall detection that has not been investigated much is direction and severity aware fall detection. Since a fall detection system aims to detect falls in people and notify medical personnel, it could be of added value to health professionals tending to a patient suffering from a fall to know the nature of the accident. In this regard, as a case study for smart health, four different experiments have been conducted for the task of fall detection with direction and severity consideration on two publicly available datasets. These four experiments not only tackle the problem on an increasingly complicated level (the first one considers a fall only scenario and the other two a combined activity of daily living and fall scenario) but also present methodologies which outperform the state of the art techniques as discussed. Lastly, future recommendations have also been provided for researchers

    An updated annotated bibliography on arc routing problems

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    The number of arc routing publications has increased significantly in the last decade. Such an increase justifies a second annotated bibliography, a sequel to CorberĆ”n and Prins (Networks 56 (2010), 50ā€“69), discussing arc routing studies from 2010 onwards. These studies are grouped into three main sections: single vehicle problems, multiple vehicle problems and applications. Each main section catalogs problems according to their specifics. Section 2 is therefore composed of four subsections, namely: the Chinese Postman Problem, the Rural Postman Problem, the General Routing Problem (GRP) and Arc Routing Problems (ARPs) with profits. Section 3, devoted to the multiple vehicle case, begins with three subsections on the Capacitated Arc Routing Problem (CARP) and then delves into several variants of multiple ARPs, ending with GRPs and problems with profits. Section 4 is devoted to applications, including distribution and collection routes, outdoor activities, post-disaster operations, road cleaning and marking. As new applications emerge and existing applications continue to be used and adapted, the future of arc routing research looks promising.info:eu-repo/semantics/publishedVersio
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