A Tree-Based Local Repairing Approach for Increasing Lifetime of Query Driven WSN

Abstract: Overlay multicast constructs a multicast delivery tree among end hosts. An important problem for making overlay multicast more dependable is how to recover from node departures in order to minimize the disruption of service to those affected nodes. In this paper, we propose a proactive tree recovery mechanism to make the overlay multicast resilient to these failures and unexpected events. The salient feature of the approach is that rescue plans for multiple non-leaf nodes can work together for their respective children when they fail or leave at the same time. Extensive simulations demonstrate that our proactive approach can recover from node departures much faster than reactive methods, while the quality of trees restored and the cost of recovery are reasonable.

Abstract: This article proposes a scheme for selecting the best site for sink placement in WSN applications employing backbone assisted communications. By placing the sink at a specific position, energy scavenging and delay constraints can effectively be controlled. In contrast to the conventional scheme for base station placement at the geographical centre or random placement at the end of the region of interest, the proposed scheme places the base station at either the graph theoretical centre or centroid of the backbone connecting nodes in the region of interest. This strategy shows a considerable reduction in the total number of hops that each packet needs to travel to reach the sink. The proposed scheme is applied on all the families of graphs prevalent in backbone assisted sensor networks to confirm the performance consistency and improvement in network parameters of the communication backbone measured in terms of delay, the carried load and the total energy consumption, eventually affected by the average number of hops for the message to reach the sink.

Abstract: The lifetime of sensor network depends on the efficient utilization of resource-constrained sensor nodes. Several MAC protocols like DMAC and its variants have been proposed to save critical sensor resources through sleep-wakeup scheduling over data gathering tree. For applications where data aggregation is not possible, the sleep duration decreases gradually from the leaves to the root of the data gathering tree. This results early failure of sensor nodes near the sink, and affects network connectivity and coverage. Deploying redundant sensors can solve this problem where a faulty node is replaced by a redundant node to maintain network connectivity and coverage. However, the amount of redundancy depends on the node failure pattern, and thus more number of redundant nodes required to be deployed near the sink. This paper proposes a gradient based sensor deployment scheme for energy-efficient data gathering exploring the trade-off among connectivity, coverage, fault-tolerance and redundancy. The density of deployment is estimated based on the distance of a node from the sink while dealing with connectivity, coverage and fault-tolerance. The effectiveness of the proposed scheme has been analyzed both theoretically and with the help of simulation.

Abstract: Network topology used to connect sensor nodes is important factor in wireless sensor networks (WSNs) that affect the energy usage of any network. Proper topology connection thereby reduces energy usage of network by reducing number of packet transmissions. Therefore node connection must be optimized in wireless sensor networks. Hence we introduce a new multiple tree based architecture of sensor network, comprising of heterogeneous nodes, to develop an energy efficient query processing WSN application. This article proposes Multi-tree and Multiple-tree algorithms for improving network parameters in the usual data collection WSN application scenarios. A multi-tree simply suggests a strategy where similar parameter type sensors are arranged in a tree based topology so as to reduce the energy consumption as well as the end to end delay in data communication. The Multiple-tree exemplifies a more effective way of query result propagation in data centric applications where delay requirements are not very stringent.

Abstract: A wireless sensor network consisting of heterogeneous sensors is capable of dealing with more than one type of information about any region at a time. Sensor applications that cater to disaster relief require faster data delivery and effective connectivity than the other monitoring applications. Moreover, usually, sensors collect a single type of data. Our approach focuses on generating a tree based communication architecture that is made up of three different types of sensors and ensures that at least one sensor of each type is connected to the communication backbone; thereby forming a MULTI-TREE. By responding to query initiated by the sink for one type of data at a time, the heterogeneous sensors ensure reduced amount of carried load and latency in data transmission. Our strategy implemented for structural health monitoring application shows that when compared to a minimum spanning tree under the same simulation constraints, performs better as it reduces the carried load and delay to one third under the existing set of ad hoc protocols.

Abstract: From the Publisher: The updated new edition of the classic Introduction to Algorithms is intended primarily for use in undergraduate or graduate courses in algorithms or data structures. Like the first edition,this text can also be used for self-study by technical professionals since it discusses engineering issues in algorithm design as well as the mathematical aspects. In its new edition,Introduction to Algorithms continues to provide a comprehensive introduction to the modern study of algorithms. The revision has been updated to reflect changes in the years since the book's original publication. New chapters on the role of algorithms in computing and on probabilistic analysis and randomized algorithms have been included. Sections throughout the book have been rewritten for increased clarity,and material has been added wherever a fuller explanation has seemed useful or new information warrants expanded coverage. As in the classic first edition,this new edition of Introduction to Algorithms presents a rich variety of algorithms and covers them in considerable depth while making their design and analysis accessible to all levels of readers. Further,the algorithms are presented in pseudocode to make the book easily accessible to students from all programming language backgrounds. Each chapter presents an algorithm,a design technique,an application area,or a related topic. The chapters are not dependent on one another,so the instructor can organize his or her use of the book in the way that best suits the course's needs. Additionally,the new edition offers a 25% increase over the first edition in the number of problems,giving the book 155 problems and over 900 exercises thatreinforcethe concepts the students are learning.

Abstract: This paper describes the concept of sensor networks which has been made viable by the convergence of micro-electro-mechanical systems technology, wireless communications and digital electronics. First, the sensing tasks and the potential sensor networks applications are explored, and a review of factors influencing the design of sensor networks is provided. Then, the communication architecture for sensor networks is outlined, and the algorithms and protocols developed for each layer in the literature are explored. Open research issues for the realization of sensor networks are also discussed.

Abstract: The primary purpose of a programming language is to assist the programmer in the practice of her art. Each language is either designed for a class of problems or supports a different style of programming. In other words, a programming language turns the computer into a ‘virtual machine’ whose features and capabilities are unlimited. In this article, we illustrate these aspects through a language similar tologo. Programs are developed to draw geometric pictures using this language.

Abstract: Advances in processor, memory, and radio technology will enable small and cheap nodes capable of sensing, communication, and computation. Networks of such nodes can coordinate to perform distributed sensing of environmental phenomena. In this paper, we explore the directed-diffusion paradigm for such coordination. Directed diffusion is data-centric in that all communication is for named data. All nodes in a directed-diffusion-based network are application aware. This enables diffusion to achieve energy savings by selecting empirically good paths and by caching and processing data in-network (e.g., data aggregation). We explore and evaluate the use of directed diffusion for a simple remote-surveillance sensor network analytically and experimentally. Our evaluation indicates that directed diffusion can achieve significant energy savings and can outperform idealized traditional schemes (e.g., omniscient multicast) under the investigated scenarios.