555 research outputs found

    Reliable cost-optimal deployment of wireless sensor networks

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    Wireless Sensor Networks (WSNs) technology is currently considered one of the key technologies for realizing the Internet of Things (IoT). Many of the important WSNs applications are critical in nature such that the failure of the WSN to carry out its required tasks can have serious detrimental effects. Consequently, guaranteeing that the WSN functions satisfactorily during its intended mission time, i.e. the WSN is reliable, is one of the fundamental requirements of the network deployment strategy. Achieving this requirement at a minimum deployment cost is particularly important for critical applications in which deployed SNs are equipped with expensive hardware. However, WSN reliability, defined in the traditional sense, especially in conjunction with minimizing the deployment cost, has not been considered as a deployment requirement in existing WSN deployment algorithms to the best of our knowledge. Addressing this major limitation is the central focus of this dissertation. We define the reliable cost-optimal WSN deployment as the one that has minimum deployment cost with a reliability level that meets or exceeds a minimum level specified by the targeted application. We coin the problem of finding such deployments, for a given set of application-specific parameters, the Minimum-Cost Reliability-Constrained Sensor Node Deployment Problem (MCRC-SDP). To accomplish the aim of the dissertation, we propose a novel WSN reliability metric which adopts a more accurate SN model than the model used in the existing metrics. The proposed reliability metric is used to formulate the MCRC-SDP as a constrained combinatorial optimization problem which we prove to be NP-Complete. Two heuristic WSN deployment optimization algorithms are then developed to find high quality solutions for the MCRC-SDP. Finally, we investigate the practical realization of the techniques that we developed as solutions of the MCRC-SDP. For this purpose, we discuss why existing WSN Topology Control Protocols (TCPs) are not suitable for managing such reliable cost-optimal deployments. Accordingly, we propose a practical TCP that is suitable for managing the sleep/active cycles of the redundant SNs in such deployments. Experimental results suggest that the proposed TCP\u27s overhead and network Time To Repair (TTR) are relatively low which demonstrates the applicability of our proposed deployment solution in practice

    Efficient and optimal routing using ant colony optimization mechanism for wireless sensor networks

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    Recently more number of routing protocols is discovered for better data routing in Wireless Sensor Network (WSN). However link failures exist in the network due to appearance of low energy nodes, low link gap connectivity while routing, etc. To compute low complexity routes and to minimize the energy consumption a nature bio inspired algorithm Ant Colony Optimization (ACO) mechanism is applied in the sensor networks. An Efficient and Optimal Routing using ACO is proposed. The premium route is determined with sub-premier nodes having high link-gap connectivity factor. The best premier nodes are selected from the sub-premier nodes on basis of bandwidth integrity and eternal energy factors for determining the premium route. The proposed work is validated by comparing the results of other existing techniques. The performance metrics proves that the proposed mechanism exhibits better throughput and delivery rate with low loss rate

    Drone Base Station Trajectory Management for Optimal Scheduling in LTE-Based Sparse Delay-Sensitive M2M Networks

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    Providing connectivity in areas out of reach of the cellular infrastructure is a very active area of research. This connectivity is particularly needed in case of the deployment of machine type communication devices (MTCDs) for critical purposes such as homeland security. In such applications, MTCDs are deployed in areas that are hard to reach using regular communications infrastructure while the collected data is timely critical. Drone-supported communications constitute a new trend in complementing the reach of the terrestrial communication infrastructure. In this study, drones are used as base stations to provide real-time communication services to gather critical data out of a group of MTCDs that are sparsely deployed in a marine environment. Studying different communication technologies as LTE, WiFi, LPWAN and Free-Space Optical communication (FSOC) incorporated with the drone communications was important in the first phase of this research to identify the best candidate for addressing this need. We have determined the cellular technology, and particularly LTE, to be the most suitable candidate to support such applications. In this case, an LTE base station would be mounted on the drone which will help communicate with the different MTCDs to transmit their data to the network backhaul. We then formulate the problem model mathematically and devise the trajectory planning and scheduling algorithm that decides the drone path and the resulting scheduling. Based on this formulation, we decided to compare between an Ant Colony Optimization (ACO) based technique that optimizes the drone movement among the sparsely-deployed MTCDs and a Genetic Algorithm (GA) based solution that achieves the same purpose. This optimization is based on minimizing the energy cost of the drone movement while ensuring the data transmission deadline missing is minimized. We present the results of several simulation experiments that validate the different performance aspects of the technique

    Energy efficient chain based routing protocol for deterministic node deployment in wireless sensor networks

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    Wireless Sensor Network (WSN) consists of small sensor devices, which are connected wirelessly for sensing and delivering specific data to Base Station (BS). Routing protocols in WSN becomes an active area for both researchers and industrial, due to its responsibility for delivering data, extending network lifetime, reducing the delay and saving the node’s energy. According to hierarchical approach, chain base routing protocol is a promising type that can prolong the network lifetime and decrease the energy consumption. However, it is still suffering from long/single chain impacts such as delay, data redundancy, distance between the neighbors, chain head (CH) energy consumption and bottleneck. This research proposes a Deterministic Chain-Based Routing Protocol (DCBRP) for uniform nodes deployment, which consists of Backbone Construction Mechanism (BCM), Chain Heads Selection mechanism (CHS) and Next Hop Connection mechanism (NHC). BCM is responsible for chain construction by using multi chain concept, so it will divide the network to specific number of clusters depending on the number of columns. While, CHS is answerable on the number of chain heads and CH nodes selection based on their ability for data delivery. On the other hand, NHC is responsible for next hop connection in each row based on the energy and distance between the nodes to eliminate the weak nodes to be in the main chain. Network Simulator 3 (ns-3) is used to simulate DCBRP and it is evaluated with the closest routing protocols in the deterministic deployment in WSN, which are Chain-Cluster Mixed protocol (CCM) and Two Stage Chain based Protocol (TSCP). The results show that DCBRP outperforms CCM and TSCP in terms of end to end delay, CH energy consumption, overall energy consumption, network lifetime and energy*delay metrics. DCBRP or one of its mechanisms helps WSN applications by extending the sensor nodes lifetime and saving the energy for sensing purposes as long as possible

    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 users’ 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

    Bio-inspired Medium Access Control for Wireless Sensor Networks

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    This thesis studies the applications of biologically inspired algorithms and behaviours to the Medium Access Control (MAC) layer of Wireless Sensor Networks (WSNs). By exploring the similarity between a general communications channel and control engineering theory, we propose a simple method to control transmissions that we refer to as transmission delay. We use this concept and create a protocol inspired by Particle Swarm Optimisation (PSO) to optimise the communications. The lessons learned from this protocol inspires us to move closer to behaviours found in nature and the Emergence MAC (E-MAC) protocol is presented. The E-MAC protocol shows emergent behaviours arising from simple interactions and provides great throughput, low end-to-end delay and high fairness. Enhancements to this protocol are later proposed. We empirically evaluate these protocols and provide relevant parameter sweeps to show their performance. We also provide a theoretical approach to proving the settling properties of E-MAC. The presented protocols and methods provide a different approach towards MAC in WSNs

    Advance in optimal design and deployment of ambient intelligence systems

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    [SPA]Se ha pronosticado un futuro excepcional para los sistemas de Inteligencia Ambiental (AmI). Dichos sistemas comprenden aquellos entornos capaces de anticiparse a las necesidades de la gente, y reaccionar inteligentemente en su ayuda. La inteligencia de estos sistemas proviene de los procesos de toma de decisión, cuyo funcionamiento resulta transparente al usuario. Algunos de estos entornos previstos pertenecen al ámbito de los hogares inteligentes, monitorización de la salud, educación, lugares de trabajo, deportes, soporte en actividades cotidianas, etc. La creciente complejidad de estos entornos hace cada vez más difícil la labor de tomar las decisiones correctas que sirvan de ayuda a los usuarios. Por tanto, la toma de decisiones resulta una parte esencial de estos sistemas. Diversas técnicas pueden utilizarse de forma eficaz en los sistemas AmI para resolver los problemas derivados de la toma de decisiones. Entre ellas están las técnicas de clasificación, y las herramientas matemáticas de programación. En la primera parte de este trabajo presentamos dos entornos AmI donde la toma de decisiones juega un papel fundamental: • Un sistema AmI para el entrenamiento de atletas. Este sistema monitoriza variables ambientales y biométricas de los atletas, tomando decisiones durante la sesión de entrenamiento, que al atleta le ayudan a conseguir un determinado objetivo. Varias técnicas han sido utilizadas para probar diferentes generadores de decisión: interpolación mediante (m, s)-splines, k-Nearest-Neighbors, y programación dinámica mediante Procesos de Decisión de Markov. • Un sistema AmI para detección de caza furtiva. En este caso, el objetivo consiste en localizar el origen de un disparo utilizando, para ello, una red de sensores acústicos. La localización se realiza utilizando el método de multilateración hiperbólica. Además, la calidad de las decisiones generadas está directamente relacionada con la calidad de la información disponible. Por lo tanto, es necesario que los nodos de la infraestructura AmI encargados de la obtención de datos relevantes del usuario y del ambiente, estén en red y situados correctamente. De hecho, el problema de posicionamiento tiene dos partes: los nodos deben ubicarse cerca de los lugares donde ocurren sucesos de interés, y deben estar conectados para que los datos capturados sean transmitidos y tengan utilidad. Adicionalmente, pueden considerarse otras restricciones, tales como el coste de despliegue de red. Por tanto, en el posicionamiento de los nodos es habitual que existan compromisos entre las capacidades de sensorización y de comunicación. Son posibles dos tipos de posicionamiento. Posicionamiento determinista donde puede seleccionarse de forma precisa la posición de cada nodo, y, aleatorio donde debido a la gran cantidad de nodos o a lo inaccesible del terreno de depliegue, sólo resulta posible la distribución aleatoria de los nodos. Esta tesis aborda tres problemas de posicionamiento de red. Los dos primeros problemas se han planteado de forma general, siendo de aplicación a cualquier tipo de escenario AmI. El objetivo es seleccionar las mejores posiciones para los nodos y mantener los nodos de la red conectados. Las opciones estudiadas son un posicionamiento determinista resuelto mediante el metaheurístico Ant Colony Optimization para dominios continuos, y un posicionamiento aleatorio, donde se realiza un despliegue cuasi-controlado mediante varios clusters de red. En cada clúster podemos determinar tanto el punto objetivo de despliegue, como la dispersión de los nodos alrededor de dicho punto. En este caso, el problema planteado tiene naturaleza estocástica y se resuelve descomponiéndolo en fases de despliegue, una por clúster. Finalmente, el tercer escenario de despliegue de red está estrechamente ligado al entorno AmI para la detección de caza furtiva. En este caso, utilizamos el método matemático de descenso sin derivadas. El objetivo consiste en maximizar la cobertura, minimizando a la vez el coste de despliegue. Debido a que los dos objetivos son opuestos, se utiliza un frente Pareto para que el diseñador seleccione un punto de operación. [ENG] A brilliant future is forecasted for Ambient Intelligence (AmI) systems. These comprise sensitive environments able to anticipate people’s actions, and to react intelligently supporting them. AmI relies on decision-making processes, which are usually hidden to the users, giving rise to the so-called smart environments. Some of those envisioned environments include smart homes, health monitoring, education, workspaces, sports, assisted living, and so forth. Moreover, the complexity of these environments is continuously growing, thereby increasing the difficulty of making suitable decisions in support of human activity. Therefore, decision-making is one of the critical parts of these systems. Several techniques can be efficiently combined with AmI environments and may help to alleviate decisionmaking issues. These include classification techniques, as well as mathematical programming tools. In the first part of this work we introduce two AmI environments where decisionmaking plays a primary role: • An AmI system for athletes’ training. This system is in charge of monitoring ambient variables, as well as athletes’ biometry and making decisions during a training session to meet the training goals. Several techniques have been used to test different decision engines: interpolation by means of (m, s)-splines, k-Nearest-Neighbors and dynamic programming based on Markov Decision Processes. • An AmI system for furtive hunting detection. In this case, the aim is to locate gunshots using a network of acoustic sensors. The location is performed by means of a hyperbolic multilateration method. Moreover, the quality of the decisions is directly related to the quality of the information available. Therefore, is necessary that nodes in charge of sensing and networking tasks of the AmI infrastructure must be placed correctly. In fact, the placement problem is twofold: nodes must be near important places, where valuable events occur, and network connectivity is also mandatory. In addition, some other constraints, such as network deployment cost could be considered. Therefore, there are usually tradeoffs between sensing capacity and communication capabilities. Two kinds of placement options are possible. Deterministic placements, where the position for each node can be precisely selected, and random deployments where, due to the large number of nodes, or the inaccessibility of the terrain, the only suitable option for deployment is a random scattering of the nodes. This thesis addresses three problems of network placement. The first two problems are not tied to a particular case, but are applicable to a general AmI scenario. The goal is to select the best positions for the nodes, while connectivity constraints are met. The options examined are a deterministic placement, which is solved by means of an Ant Colony Optimization metaheuristic for continuous domains, and a random placement, where partially controlled deployments of clustered networks take place. For each cluster, both the target point and dispersion can be selected, leading to a stochastic problem, which is solved by decomposing it in several steps, one per cluster. Finally, the third network placement scenario is tightly related to the furtive hunting detection AmI environment. Using a derivate-free descent methodology, the goal is to select the placement with maximal sensing coverage and minimal cost. Since both goals are contrary, the Pareto front is constructed to enable the designer to select the desired operational point.Universidad Politécnica de Cartagen

    Self-organizing nest migration dynamics synthesis for ant colony systems

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    In this study, we synthesize a novel dynamical approach for ant colonies enabling them to migrate to new nest sites in a self-organizing fashion. In other words, we realize ant colony migration as a self-organizing phenotype-level collective behavior. For this purpose, we first segment the edges of the graph of ants' pathways. Then, each segment, attributed to its own pheromone profile, may host an ant. So, multiple ants may occupy an edge at the same time. Thanks to this segment-wise edge formulation, ants have more selection options in the course of their pathway determination, thereby increasing the diversity of their colony's emergent behaviors. In light of the continuous pheromone dynamics of segments, each edge owns a spatio-temporal piece-wise continuous pheromone profile in which both deposit and evaporation processes are unified. The passive dynamics of the proposed migration mechanism is sufficiently rich so that an ant colony can migrate to the vicinity of a new nest site in a self-organizing manner without any external supervision. In particular, we perform extensive simulations to test our migration dynamics applied to a colony including 500 ants traversing a pathway graph comprising 200 nodes and 4000 edges which are segmented based on various resolutions. The obtained results exhibit the effectiveness of our strategy
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