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An Effective Data Aggregation Mechanism in Wireless Sensor Networks
, M.Sc. Thesis Sharif University of Technology ; Jahangir, Amir Hossein (Supervisor)
Abstract
Wireless sensor networks (WSNs) are tiny devices with limited computation and power supply. For such devices, data transmission is a very energy-consuming operation. Data aggregation eliminates redundancy and minimizes the number of transmissions in order to save energy. This research explores the efficiency of data aggregation by focusing on different aspects of the problem such as energy efficiency, latency and accuracy. To achieve this goal, we first investigate data aggregation efficiency with constraint on delay, which can be compatible with other important system properties such as energy consumption and accuracy. By simulation, we will show that, depending on the application, we can...
A Cross Layer Approach for Real-Time Communication in Wireless Sensor Networks
, M.Sc. Thesis Sharif University of Technology ; Movaghar, Ali (Supervisor) ; Khansari, Mohammad (Supervisor)
Abstract
Most of current the MAC protocols for Wireless Sensor Networks (WSNs) concern about energy efficiency rather than low latency. The main source of energy consumption in the MAC layer is idle listening, and most of these protocols use duty cycling for reducing energy consumption. But duty cycling method increases packet delivery latency. This problem is very critical in real time applications where packets should meet their deadline. There are some solutions for this problem. For example a node forwards data packets multi hop away instead of one hop in a single cycle. In this research, an efficient cross layer MAC protocol for real time applications is proposed. In this protocol multi hop...
A Heuristic Method for Optimization of Node Placement in Wireless Sensor Network
,
M.Sc. Thesis
Sharif University of Technology
;
Hemmatyar, Ali Mohammad Afshin
(Supervisor)
Abstract
As the applications of wireless sensor networks are expanding at an increasing rate, design of these networks so that they conform to the requirements of a specific application is considered to be a major challenge. Regarding to the specific application, network designers consider various suitable parameters to improve and then to enhance the efficiency of the network. Parameters included are such as area coverage, lifetime, reliability and etc which can significantly improve with the precise placement of nodes. Node localization problem in wireless sensor networks aiming at improvement of the performance parameters has been solved by different methods. In this thesis, in order to solve this...
A QoS-Aware Routing Algorithm in Wireless Multimedia Sensor Network Using Cross-Layer Information
, M.Sc. Thesis Sharif University of Technology ; Khansari, Mohammad (Supervisor)
Abstract
In this thesis, we propose a QoS-aware routing algorithm for multimedia streaming that uses cross-layer information (application layer and physical layer) in Wireless Multimedia Sensor Networks (WMSN). Our goal is to use cross-layer information to route video packets efficiently and deliver a higher quality video in streaming applications. Our QoS-Aware Multi-Path Selection (QAMPS) method is based on multi-path multi-priority selection algorithm that uses Two-Phase geographic Greedy Forwarding (TPGF) as a routing algorithm. The proposed method guarantees QoS by splitting video streams into I-frames, P-frames and B-frames in the application layer and passes them to the network layer for...
Distributed Learning in Wireless Sensor Networks
, Ph.D. Dissertation Sharif University of Technology ; Bagheri Shouraki, Saeed (Supervisor)
Abstract
Wireless Sensor Networks (WSNs) attracted lots of researchers in recent years, these sensors are small and have limited computational resources and are not expensive in comparision with conventional sensors. These sensors can sense, measure, gathering information from environment and send them to user, they are typically characterized by limited communication capabilities due to tight energy and bandwidth constraints. As a result, WSNs have inspired a resurgence in research on decentralized algorithms, structure of these networks are variable and dynamic, sensors may deleted from the network or added to the network, so using models which don’t require precies specifications of environment is...
Efficient Congestion Control in ZigBee-Based Wireless Sensor Network
, M.Sc. Thesis Sharif University of Technology ; Manzuri, Mohammad Taghi (Supervisor)
Abstract
Sensor networks is a set of sensors (nodes) which are communicating with each other, and gather information from different environments, and process them to give us valuable results. Sensors have a small energy source like a small battery which have to be used efficiently. Congestion detection and avoidance, together are of great importance in Wireless Sensor Networks (WSNs) in case of traffic load, data loss, and power consumption. In this work, we propose a new APS layer (application support sub-layer), which is another key standard component of Application layer, offering a well-defined interface and several control services. It functions as a bridge between the network layer and other...
Congestion Control in Wireless Multimedia Sensor Networks
, M.Sc. Thesis Sharif University of Technology ; Hemmatyar, Ali Mohammad Afshin (Supervisor)
Abstract
Distinguishing characteristic of wireless sensor network is limited resources such as processing power, bandwidth, memory. Restrictions of sensor networks is impressive on the transfer of multimedia data such as video requiring high bandwidth and low latency. In wireless multimedia sensor networks, the probability of packet loss is high due to the high volume of multimedia data and limited bandwidth. Many congestion control protocols for wireless sensor networks have presented. Most of these protocols did not consider the multimedia content. Even some wireless sensor network congestion control protocols have worse result than a network which has no congestion control protocol in case of...
Data Reduction and Aggregation in Wireless Sensor Networks
, M.Sc. Thesis Sharif University of Technology ; Movaghar Rahimabadi, Ali (Supervisor)
Abstract
Data transmission consumes most of the power resources in wireless sensor networks. Con-sequently, a large number of methods have been devised to cope with this problem. In this thesis, we propose a data reduction algorithm based on the transmission workload of interme-diate nodes. We aggregate the incoming packets to the intermediate nodes into one packet by employ ing the Principal Component Analysis (PCA). Therefore, each intermediate node only sends one packet in stead of relaying all the incoming packets and hence we achieve consid-erable reduction in power consumption at those nodes. Although this approach imposes some delay for buffering the incoming packets, but extending the...
Reduction of Energy Consumption in Wireless Sensor Networks Using Genetic Algorithm
, M.Sc. Thesis Sharif University of Technology ; Hemmatyar, Ali Mohammad Afshin (Supervisor)
Abstract
Reducing energy consumption is one of the challenges facing wireless sensor networks with many solutions introduced for them with each having advantages and disadvantages. Some of the solutions introduced are based on using movable sinks. In this project, we attempt at proposing a place for the establishment of sinks using genetic algorithm that can reduce energy consumption in the net knots and increase the net life. This work should be done after reviewing the results of past researches and introduced methods. We will analyze the practicality of the proposed model using simulation and will show their advantages over the previous mentioned methods
A Multi-Weight Based Clustering Algorithm for Mobility Wireless Sensor Network
, M.Sc. Thesis Sharif University of Technology ; Hemmatyar, Ali Mohammad Afshin (Supervisor)
Abstract
Wireless sensor network (WSN) is a wireless network composed of spatially distributed autonomous devices using sensors to cooperatively monitor physical or environmental conditions data such as temperature, pressure, humidity, and so on[1-4]. In recently years, WSN has been applied to widely various areas. Since sensors are equipped with small batteries, which are costly if not impossible to recharge or replace, sensor network operations must be energy efficient in order to maximize the network lifetime. Given the power constraints in sensors, investigations into routing protocols in order to extend the...
The CBK-Neigh Protocol for Symmetric Topology Control in Ad Hoc Networks
, M.Sc. Thesis Sharif University of Technology ; Beigy, Hamid (Supervisor)
Abstract
Several applications have been envisioned for wireless sensor networks (WSNs). These range in scope from military applications to environment monitoring to biomedical applications. It is a widely accepted fact that the limited energy available at the nodes of a wireless sensor network must be used as efficiently as possible. If energy conservation techniques are used at different levels, the functional lifetime of both individual nodes and the network can be extended considerably.
Energy can be saved if the network topology itself is energy-efficient. The research in topology construction and connectivity has been approached independently along two paths. In one path, researchers aim to...
Energy can be saved if the network topology itself is energy-efficient. The research in topology construction and connectivity has been approached independently along two paths. In one path, researchers aim to...
Fusion of Audio and Visual Occurrences using Fuzzy Logic for Improving Perception Quality of Events
, Ph.D. Dissertation Sharif University of Technology ; Bagheri Shouraki, Saeed (Supervisor)
Abstract
The ability of human to analyze the environment around them has been an inspiring source for event analysis research. Since human perception of the environment is formed in a multi-modal space, many efforts have been made to fuse information to create an intelligent fusion. In this study, we want to better understand the environment using information fusion. For this purpose, fuzzy fusion of audio and video signals based on ink drop spread operator is performed for recognizing and tracking of the targets using several scenarios of the AV16.3 dataset. We then focused on the fusion of audio data for sound source localization, one of the most important applications in evaluating fusion...
A Rate Control Mechanism for Wireless Multimedia Sensor Networks
, M.Sc. Thesis Sharif University of Technology ; Khansari, Mohammad (Supervisor) ; Akbari, Behzad (Co-Advisor)
Abstract
To make Wireless Multimedia Sensor Networks (WMSNs) more practical, researchers have tried to meet its challenges in the last decade. Some factors of WMSNs, such as low bandwidth and channel errors, cause a decrease in the video quality that is declared as distortion. On the other hand, one important requirement in the context of multimedia streaming is its quality. In this thesis, we first introduce and use an adaptive cross-layer error control in the link layer, and then we implement a new cross-layer source rate control Mechanism for efficient and reliable real-time multimedia streaming in wireless sensor networks. Our main objective is to minimize distortion. Some of the used cross-layer...
Accurate and Low-Cost Location Estimation using Machine Learning Techniques in Wireless Sensor Networks
, M.Sc. Thesis Sharif University of Technology ; Beigy, Hamid (Supervisor)
Abstract
Wireless sensor networks have a wide range of applications in the world. In most of the applications, collected data is not usable without the knowledge about the localization of events. There are two approaches to specifying the location of a sensor: using hardware solutions such as GPS, which is an expensive solution, and using the localization algorithm. Therefore, localization has an important role in sensor networks. Most of the current localization algorithms are non-adaptive and proposed for fixed wireless sensor networks. Recently, adaptive localization algorithms have been considered because of their simple implementation, fast result and low computation overhead for each node. In...
Location Finding in Wireless Sensor Network Based on Range-Free Schemes
, M.Sc. Thesis Sharif University of Technology ; Manzuri, Mohammad Taghi (Supervisor)
Abstract
Sensor Localization is a crucial part of many location‐dependent applications that utilize wireless sensor networks (WSNs). Several approaches, including range‐based and range‐free, have been proposed to calculate the position of randomly deployed sensor nodes. With specific hardware, the range‐based schemes typically achieve high accuracy based on either node‐to-node distances or angles. On the other hand, the range‐free mechanisms support less positioning accuracy with less expense. The proposed scheme is based on range‐free localization, which utilizes the received signal strength (RSS) from the anchor nodes. In this work, genetic fuzzy and neuro-fuzzy systems are used to yield more...
Automatic Acoustic Localization in Sensor Networks Using Environmental Natural Acoustic Phenomena
, M.Sc. Thesis Sharif University of Technology ; Abolhassani, Hassan (Supervisor)
Abstract
We propose a range-free localization framework in which a network of randomly deployed acoustic sensors can passively use natural acoustic phenomena within its environment to localize itself. We introduce a novel approach for registration of sensors observations which takes advantage of a clustering technique on triplets of associated observations. A Bayesian filtering method is employed to incrementally improve system state estimation as more observations become available. To the best of our knowledge this is the first work done on range-free passive acoustic localization. Furthermore, we have proposed a simple but effective and efficient acoustic detection method which can be used to...
Sensor Network Localization Using Semidefinite Representations and Facial Reductions
, M.Sc. Thesis Sharif University of Technology ; Mahdavi Amiri, Nezamoddin (Supervisor)
Abstract
Use of wireless sensor networks (WSNs) to record environmental data such as temperature, sound level, and light intensity has grown dramatically. The specification of the locations of sensors is important. Using tools such as global positioning system (GPS) to find the location of sensors is not economical. Sensors can record their distances from neighboring sensors. On the other hand, the locations of some sensors are fixed. In wireless sensor network localization (SNL), we want to find the location of sensors using the available information. An approach for solving the SNL problem is to model the problem as an optimization problem and use an interior point method for its solution. Interior...
A New Hierarchal and Scalable Architecture for Performance Enhancement of Large Scale Underwater Sensor Networks
, M.Sc. Thesis Sharif University of Technology ; Movaghar, Ali (Supervisor)
Abstract
Underwater Sensor Network (UWSN) is new branch of Wireless Sensor Network (WSN). UWSNs are considerably different from ground base or terrestrial sensor networks in many aspects. These new features bring many challenges to the network architecture or protocol design of UWSNs. This kind of sensor networks has been proposed to detection, monitoring, protecting the oceans as oceanographic data collector, pollution monitoring, offshore exploration, disaster prevention, assisted navigation and tactical surveillance applications. The different characteristics of UWSN and trade off between UWSN and WSN have been discussed in many researches. Here we aim to propose a new architecture for very large...
Opportunistic Routing in Mobile Wireless Sensor Networks
, M.Sc. Thesis Sharif University of Technology ; Movaghar Rahimabadi, Ali (Supervisor)
Abstract
Routing is one of the most challenging areas in wireless sensor networks because it has a significant impact on energy usage, transmit delay and network fault tolerance. In many situations, network nodes move around and it cause numerous challenges, namely changes in routing paths, failure in sending packets or maybe there is no end-to-end path. Opportunistic routing is one of the best solutions to these problems in mobile wireless sensor networks, thus it provides more efficient routing and less energy consumption in comparison with traditional routings.
In opportunistic routing, nodes try to utilize every opportunity to send their packets to sink. When two nodes are encountered, the...
In opportunistic routing, nodes try to utilize every opportunity to send their packets to sink. When two nodes are encountered, the...
A Game Theory Approach for Finding Optimal Route in Wireless Sensor Networks
,
M.Sc. Thesis
Sharif University of Technology
;
Eshghi, Kourosh
(Supervisor)
Abstract
In this thesis, a “Game Theory” approach for finding an optimal path in a “Wireless Sensor Network” is discussed. WSN is one of the most interesting research fields in the communication networks, and is the center of attention in recent years. In our model, a pricing and payment technique is presented to obtain an optimal path in a WSN by considering reliability, energy, and traffic load. The proposed algorithm is able to find a path which improves network lifetime and load distribution.