Approximation schemes for load balanced clustering in wireless sensor networks

Clustering sensor nodes is an efficient technique to improve scalability and life time of a wireless sensor network (WSN). However, in a cluster based WSN, the leaders (cluster heads) consume more energy due to some extra load for various activities such as data collection, data aggregation, and communication of the aggregated data to the base station. Therefore, balancing the load of the cluster heads is a crucial issue for the long run operation of the WSNs. In this paper, we first present a load balanced clustering scheme for wireless sensor networks. We show that the algorithm runs in O(nlogn) time for n sensor nodes. We prove that the algorithm is optimal for the case in which the sensor nodes have equal load. We also show that it is a polynomial time 2-approximation algorithm for the general case, i.e., when the sensor nodes have variable load. We finally improve this algorithm and propose a 1.5-approximation algorithm for the general case. The experimental results show the efficiency of the proposed algorithm in terms of the load balancing of the cluster heads, execution time, and the network life.     

Bounded Tamper Resilience: How to Go Beyond the Algebraic Barrier

Related key attacks (RKAs) are powerful cryptanalytic attacks where an adversary can change the secret key and observe the effect of such changes at the output. The state of the art in RKA security protects against an a-priori unbounded number of certain algebraic induced key relations, e.g., affine functions or polynomials of bounded degree. In this work, we show that it is possible to go beyond the algebraic barrier and achieve security against arbitrary key relations, by restricting the number of tampering queries the adversary is allowed to ask for. The latter restriction is necessary in case of arbitrary key relations, as otherwise a generic attack of Gennaro et al. (TCC 2004) shows how to recover the key of almost any cryptographic primitive. We describe our contributions in more detail below. (1) We show that standard ID and signature schemes constructed from a large class of \(\Sigma \)-protocols (including the Okamoto scheme, for instance) are secure even if the adversary can arbitrarily tamper with the prover’s state a bounded number of times and obtain some bounded amount of leakage. Interestingly, for the Okamoto scheme we can allow also independent tampering with the public parameters. (2) We show a bounded tamper and leakage resilient CCA-secure public key cryptosystem based on the DDH assumption. We first define a weaker CCA-like security notion that we can instantiate based on DDH, and then we give a general compiler that yields CCA security with tamper and leakage resilience. This requires a public tamper-proof common reference string. (3) Finally, we explain how to boost bounded tampering and leakage resilience [as in (1) and (2) above] to continuous tampering and leakage resilience, in the so-called floppy model where each user has a personal hardware token (containing leak- and tamper-free information) which can be used to refresh the secret key. We believe that bounded tampering is a meaningful and interesting alternative to avoid known impossibility results and can provide important insights into the security of existing standard cryptographic schemes.     

Coverage and connectivity aware energy efficient scheduling in target based wireless sensor networks: an improved genetic algorithm based approach

Wireless Networks - Energy efficient scheduling of sensor nodes is one of the most efficient techniques to extend the lifetime of the wireless sensor networks (WSNs). Instead of activating all the...     

Coverage and connectivity aware critical target monitoring for wireless sensor networks: Novel NSGA‐II–based approach

As sensor nodes have limited sensing and transmission capability, their efficient deployment takes an important role in proper monitoring of the critical targets in various applications of wireless sensor networks (WSNs). The key issues that need to be taken care during deployment are the lesser number of deployed sensors, coverage of the targets, and connectivity between the sensor nodes. In this paper, we have proposed NSGA‐II with modified dominance to solve the node deployment problem with the aforementioned three conflicting objectives. The conventional domination method is modified for better performance of the NSGA‐II. An intelligent representation of chromosome is provided. Three conflicting objectives are derived to evaluate the chromosomes. Extensive simulation on the proposed algorithm and the statistical test, and analysis of variance (ANOVA) followed by post hoc analysis are performed.     

Binary quantum-inspired gravitational search algorithm-based multi-criteria scheduling for multi-processor computing systems

A quantum-inspired hybrid scheduling technique is proposed for multi-processor computing systems. The proposed algorithm is a hybridization of principles of quantum mechanics (QM) and a nature-inspired intelligence, gravitational search algorithm (GSA). The principles of QM such as quantum bit, superposition and rotation gate help to design an efficient agent representation as well as intense exploration capability of GSA enhances toward better converging rate. The fitness function is designed with the aim to minimize makespan, adequate balancing of loads and proper utilization of the deployed resources during the evaluation of agents. Several standard benchmarks as well as synthetic data sets are used to analyze and validate the work. The performance improvement of the proposed algorithm is compared with recently designed algorithms like quantum genetic algorithm, particle swarm optimization-based multi-criteria scheduling, Improved-GA, GSA and Cloudy-GSA. The significance of the algorithm is tested using a hypothesis analysis of variance.

     

A novel leader election algorithm based on resources for ring networks

The leader node in a distributed computing system is responsible to establish coordination among all other nodes that are situated apart geographically. Selection of a suitable leader is one of the major and challenging problems. In this paper, a novel leader election algorithm is proposed based on resources of each node in a ring network. All the nodes compute resource strength values by considering available resources like CPU, memory capacity, and residual energy. A node with the highest resource strength over the network is elected as the leader. The proposed algorithm has also considered sudden failure of the nodes particularly when it is the leader node. Moreover, addition of new nodes is also considered. The proposed algorithm shows improvement on message complexity over the network and resource‐based priority generation, which helps in efficient election of the leader. To validate, the proposed algorithm is extensively simulated as well as real‐life hardware experiment is also done. In the experiment, 2 cases are considered with different weight of the resources, and consequent effects are shown. The results are also compared with the existing algorithms, and it is observed that the proposed work comparably performs better that the existing related algorithms.     

Synthesis and characterization of sol gel derived nontoxic CZTS thin films without sulfurization

Recently, great attention has been paid to the development of earth rich and nonhazardous Copper Zinc Tin Sulfide (CZTS–Cu₂ZnSnS₄) thin films for application in photovoltaic devices owing to its high absorption coefficient over the visible and infrared region. However, sulfurization process is an indispensable step in growing stoichiometric thin film using conventional physical vapor deposition. Hence, it is imperative to devise a liquid based technique without intentional sulfurization for the optimum quality growth of CZTS thin films. In the current work, layer-by-layer sol-gel deposition technique was utilized to grow high quality CZTS thin films without sulfurization and their structural and optical characteristics were investigated using XRD studies and UV-visible spectroscopy respectively. The morphology and chemical composition of the prepared CZTS films are estimated by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) analysis respectively. Highly absorbing and crystalline CZTS films have been successfully grown in the present work which could be further utilized as an absorber layer in photovoltaic applications.     

A novel scheduling with multi-criteria for high-performance computing systems: an improved genetic algorithm-based approach

Engineering with Computers - Scheduling in high-performance computing systems is experiencing potential challenges in modern computing applications due to different application sizes, computational...