Sharif Digital Repository

This research presents an efficient thermal-aware routing protocol based on Shortest Hop Routing algorithms for implanted bi medical sensor network. Implanted biomedical sensor networks provide a major application of sensor networks in the near future. These in-vivo sensor nodes collect desired biometric data and communicate the data wirelessly to a base-station through a multi-hop network. They generate the heat due to wireless communication and circuitry power consumption. A high temperature of the in-vivo nodes for a prolonged period might damage the surrounding tissues. Most of the protocols for sensor networks don’t take the thermal issue as a factor in the routing of packets. In its... 

Let P be a set of points in the plane, each equipped with a directional antenna that can cover a sector of angle and range r. In the symmetric model of communication, two antennas u and v can communicate to each other, if and only if v lies in u’s coverage area and vice versa. In this paper, we introduce the concept of fault-tolerant spanners for directional antennas, which enables us to construct communication networks that retain their connectivity and spanning ratio even if a subset of antennas are removed from the network. We show how to orient the antennas with angle and range r to obtain a k-fault-tolerant spanner for any positive integer k. For ⩾ , we show that the range 13 for the... 

Wireless sensor networks (WSNs) are composed of many independent spatially-distributed sensor nodes where communicate their information acquired from environment to shape a uniform view of their managed scope. Using WSNs in places which human can hardly attend uninterruptedly, as well as constraints such as low power consumption, low price, small size, and limited radio range, are the biggest challenges for researchers and WSN designers. Supplying security is yet another common challenge of using these networks. The beginning chapters of this dissertation introduce the most important security mechanisms in WSNs, that is, key management and cryptography. Since each application has its own... 

Nowadays, Wireless Sensor Networks (WSNs) play a role in the field of information technology for data gathering purposes. In general, each WSN contains many inexpensive wireless nodes, each capable of collecting, processing, and storing environmental information, and communicating with neighboring nodes. WSNs have been successfully used in different applications such as object tracking, emergency guiding, and environment monitoring. The popular WSN platforms in real-world applications are MICAz, Tmote , and Dust Network. Two standards, namely the ZigBee and IEEE 802.15.4 standards are projected to provide interoperability of different platforms, and to define physical, MAC, and network... 

Technology advances in the era of wireless communications leads to the birth of a very useful network called Wireless sensor Network which is very interesting for scientists and researchers. While these networks consist of tens to thousands of tiny sensor nodes, they consume their energy from none-rechargeable batteries. Reducing energy consumption and extend the life of network is the most challenging requirement for these kinds of networks; in some environments like military training which precision and sensitivity are critical, it might take at least K sensors to cover the whole area and these conditions leads to a vast data repetition in network and as a result energy exhaustions in... 

Energy constraint is the most critical problem in wireless sensor networks (WSNs). To address this issue, clustering has been introduced as an efficient way for data aggregation and routing. However, there also exist some disadvantages associated with the clustering scheme, such as additional overheads during the cluster-head election and cluster formation process. Most available clustering algorithms do not efficiently take into consideration the geographical information of nodes in the cluster-head election. This leads to uneven distribution of cluster-heads and unbalanced cluster sizes, which brings about uneven energy dissipation in clusters. In this research, an Efficient Distributed... 

Recent advances in Micro-Electro-Mechanical Systems (MEMS) technology, wireless communications,and digital electronics have enabled the development of low-cost, low-power,multifunctional sensor nodes that are small in size and communicate untethered in short distances.Wireless Sensor Network (WSN) including these sensors has been utilized in many applications, namely military and environmental applications. Due to unchangeable battery in most WSNs, Power consumption is an important challenge in such systems. A sensor node expends maximum energy in data communication. Control environmental parameter is among the most important applications of WSN. The actual physical environmental information... 

Wireless Sensor Networks (WSNs) consist of few hundred to thousand sensor nodes that are usually deployedrandomly in a sensing field. The duty of sensor nodes is to sense the environment for data collection and sending these data to a sink node for future processes. Sensor nodes are equipped with a non-rechargeable battery. Hence, network lifetime is an important issue in WSNs. When a static sink node is used in a WSN, sensor nodes that are located in the neighborhood of the sink node willdrain out of energy faster than other sensor nodes which are farther away from the sink node, because traffic load is heavier on sensor nodes which are closer to the sink node. This problem is named “the... 

Nowadays, regarding the advancement of unmanned aerial vehicles and low cost sensors, the idea of utilizing a group of aerial vehicles to perform risky and complicated missions has attracted the attentions of researchers. One of the main subjects in aerial missions is target search and localization. Cooperative target search by the use of multiple aerial vehicles equipped with sensors, could construct a sensor network that makes the system more robust against failures and reduce noises and uncertainties. In addition, the observability and quality of sensor signals could increase if the motion and positions of the vehicles are intelligently optimized.In this research, establishing an... 

Coverage rate is a critical criterion in all of communication networks. In this regard, there are many different methods for distribution of network particles duo to attain the most efficient region of coverage. This emerges from the limited ability of each networks particle both in range of communicate and power consumption. In this thesis an evolutionary method is introduced to how Wireless Sensor Networks (WSN) particles can be dispensed to have more reliable coverage rate. Using both static and mobile sensor packages to cover the desired area and used a cost function, coverage rate, the authors tried to maximize it to have an excellent performance of network. Then proposed algorithm is... 

Recent advancement in wireless communications, electronics, low power design and also tendency to use high performance low cost products have led to emergence of Wireless Sensor Networks (WSNs). As the main purpose of a WSN is information gathering and it’s transmission to the sink node, the main problem is to deliver information correctly with minimum energy consumption. Besides, whereas the majority of developed applications for WSNs are event-critical applications, achieving reliable data transfer as the main factor of dependability and quality of service seems vital. However, data transmission is unreliable over multi-hop WSN due to the unreliability of wireless links and node failures. ... 

Real-time asynchronous data fusion for high-speed phenomena is an important and challenging task in the sensor networks. Examples of data fusion applications in sensor networks are: managing the traffic of maneuvering airplanes and ground vehicles in airside areas of an airport, traffic management in streets and roads, Driver Assistance Systems, guidance of antiaircraft and antimissile missiles. In all the data fusion applications the estimation of the required variables is necessary.
In this research two methods are introduced for real-time asynchronous data fusion, especially for track-to-track fusion of high-speed phenomena in sensor networks. The effectiveness and usability of these... 

Given a set of obstacles as an arrangement of geometric shapes in the plane, we would like to find a path from the initial point s to the target point t that crosses the minimum number of obstacles. In other words, the goal is to determine the minimum number of obstacles that need to be removed to exist a collision-free path between s and t.On one hand, this problem can be used for measuring the strength of barrier coverage which is a fundamental concept in wireless sensor networks (WSNs), and on the other hand, it has been considered as a robot motion-planning problem. The objective of barrier coverage is to guarantee that any path from the start point to the target point, will intersect at... 

Wireless Sensor Networks (WSNs) are rapidly emerging as an important area in mobile computing research. Applications of WSNs are numerous and growing, some of them are even highly critical, like military or safety applications. Security measures must be applied to protect the network from a variety of attacks. Since no intrusion prevention measure is perfect, intrusion detection becomes an important second wall to protect the network. WSNs have unique nature which is different from other kinds of networks. In this project, we examine the characteristics and vulnerabilities of WSNs and propose a new intrusion detection model to protect the network security. In this work we have not only... 

To provide a safe environment for space equipments and infrastructures in addition to managing the role of hazardous objects that are known as space debris, the presented thesis describes a new robust technique to estimate the dynamic states and inertial parameters of Uncooperative Space Objects (USO) with uncertain dynamics in the cluttered orbits. The prescribed method is especially effective to capture stray objects, capture and servicing of the satellites, rendezvous and collision avoidance maneuvers, space explorations as well as Actrive Debris Removal (ADR) missions. Such missions call for high degree of precision and reliable estimation methods. The proposed estimation architecture... 

In recent years, significant interest has been attracted towards using directional antennae in wireless and sensor networks due to it’s decreased energy consumption, increased security and decreased radio wave overlapping. Substituting omni-directional antennae with directional antennae should be performed in a way that not only guarantees connectivity, but also minimizes radius and latency in network nodes. The problem is not polynomially solvable in general and effort has been made in recent years to present approximation algorithms to solve this problem. The approximation algorithms have been made possible using unit disk
graphs, Euclidean minimum spanning trees, grouping of... 

Recently there is a huge growth in industrial automation. Industrial automation is defined as trying to do some tasks automatically and without direct human intervention. Using industrial automation may help increasing efficiency, quality and safety. Industrial automation also could increase Competitiveness and flexibility of industries. In human life there is a large area of activities that automation could be used and different industries like oil and gas companies, electrical generation and distribution industries, medical companies, textile and other industries could use automation to increase their efficiency. But recently there is a growing demand for building automation and home... 

There are several applications of wireless sensor networks wherein the data collected by the sensors in the network are critical and hence have to be reliably transported to the sink, example of such applications are fire detection in a forest or controlling vibration on body of dam. Reliable communication in wireless sensor networks is hard to achieve efficiently using methods in conventional systems like Internet. End-to-end retransmission is inefficient, or in some cases impossible. It is well-known that Reed-Solomon codes may be used to provide error correction for multiple failures in RAID-like systems. To the coding theorists, this technique is a straight forward extension to a basic... 

Wireless Sensor Networks (WSNs) are comprised of small sensor nodes with very limitedstorage, power and computational capabilities. The nodes in wireless sensor networks should be able to communicate with each other in order to accumulate information and to relay it to a base station in a secure manner. Since this communication often takes place in a hostile environment, encryption and/or authentication should be used. This requires the establishment of secure keys between the sensor nodes in the WSN. The constraints of such a lightweight distributed computing environment lend itself to the use of symmetric cryptography to provide security services. The lack of central infrastructure after... 

Minimizing energy consumption is the most important concern in wireless sensor networks (WSNs). Cooperative multiple-input multiple-output (MIMO) and data aggregation are two promising techniques to conserve energy in network nodes by coordinating their transmissions through cooperative communications along with eliminating the inherent redundancy of raw data for transmissions. In this thesis, with the goal of reducing energy consumption, we present a dynamic clustering framework for combined used of cooperative MIMO and data aggregation in cluster-based WSNs. We derive a new and more general energy model for computing energy consumption of cooperative data aggregation in wireless sensor...