The current issue of the IETE Journal of Research (Vol.61, No.5, September–October 2015) contains 14 articles. These articles present on-going research and developments taking place in the broad areas of Electrical Engineering, Communication Engineering, Wireless Sensor Networks, Microelectronics and Neuro Fuzzy systems.
The paper ‘Modeling and control of active clamp forward converter with center tap transformer’, deals with dynamic modeling of the power stage, controller design, open-loop and closed-loop analyses of an active clamp forward converter with center tap transformer and gives the experimental results. This topology is useful for onboard dc-dc converters in telecommunications electronics due to its high efficiency and power density.
In the paper ‘Connectivity-based cross-layer opportunistic forwarding for MWSNs’, the authors give a routing protocol for mobile wireless sensor networks that is connectivity and cross-layer opportunistic based. It takes into account the topological changes in such networks due to node mobility to enhance the energy efficiency and reduce network overheads. The efficacy of the protocol is presented and compared with other protocols through simulation studies.
The next paper titled ‘Comparing proposed signature with SURF in object detection process’, presents an algorithm to detect objects and match them based on their own signature using morphological processing. The regions of interest for the matching process are obtained from constructed object signatures. The algorithm performance is studied with a dataset of dissimilar objects and compared with the SURF algorithm.
The paper titled ‘Virtual source-based location privacy for wireless sensor networks’, is concerned with the privacy of packet data in wireless sensor networks. It uses a method of virtual source node for routing purposes to prevent an adversary accessing the communication. The proposed method has been studied using Omnett++ based Castalia environment.
In the paper ‘Energy-efficient resource allocation for multi-cell OFDM networks’, the authors give a non-convex optimization formulation to maximize the energy efficiency of a multi-cell OFDM network with different user distributions in different cells. The fractional optimization problem is solved iteratively using graph-based technique for the sub-carrier allocation and power allocations to maximize the energy efficiency of the network. The simulation study makes inferences regarding energy efficiency and network capacity and is compared with a baseline algorithm.
The next paper on ‘An MDP approach for defending against fraud attack in cognitive radio networks’, presents a reinforcement learning based decision making method to find the optimal strategy for channel selection for secondary users in a cognitive radio network. The paper considers the effects of collision fraud and sensing error simultaneously. The model has been evaluated for different optimal strategies for secondary users to find time slots in primary bands.
In ‘Design of single input fuzzy logic controller for shunt active power filter’, the authors describe the application of single input fuzzy logic controller for a three-phase shunt active power filter. A conventional two-input fuzzy logic controller is reduced to single-input one to reduce the number of rule inferences and simplify the tuning of control parameters. The performance and execution time of the controller is compared in simulation with a conventional fuzzy logic controller, and a dSPACE prototype's performance is also presented.
The paper titled ‘Phase-type model spectrum sensing for cognitive radios’, gives a method for adaptive spectrum sensing for cognitive radios using Markov chain phase-type modeling. It addresses the issue of computational efficiency for secondary users to detect the channel state under collision constraints. The method provides for trade-off between sensing time, the false alarm and miss probabilities of the receiver sensor.
In the paper ‘Realization of electronically controllable current-mode full-wave rectifier’, the authors present realization of full-wave rectifier of sinusoidal signals using controlled current conveyors, MOS transistors, and capacitor, and does not require external resistors and component matching. The theoretical analysis is provided along with circuit p-Spice simulation studies, and experimental results.
The paper ‘Load frequency control of multi-area power systems using Neuro-fuzzy hybrid intelligent controllers’, presents an automatic generation control of three unequal area hydro-thermal power systems using artificial neural networks and fuzzy-based adaptive Neuro-fuzzy inference systems. The performances of the controllers have been studied using simulations, and inferences are drawn from this study.
The paper ‘Process-induced delay variation in SWCNT, MWCNT, and mixed CNT interconnects’, gives analysis of propagation delay in carbon nanotube bundled interconnects that result from process-induced variations. A multi-conductor transmission line model of the mixed carbon nanotube bundle and related interconnects has been presented and studied in simulation environment for variations in propagation delay under variations of temperature, metallic to semiconducting ratio, contact resistance and other parameters.
In the next paper titled ‘Detecting location-based attacks in wireless sensor networks using sequential analysis’, the authors consider the problem of tampered nodes of a wireless sensor network that launch location based attacks and disrupt network operations by giving a method to detect and isolate malicious nodes based on sequential probability ratio test. The method is incorporated in the Greedy Perimeter Stateless Routing protocol and the efficacy is studied using NS-2 simulation environment in terms of false positive and false negative rates.
The paper on ‘Non-interactive anonymous credential based on structure-preserving signature’, is concerned with the construction of non-interactive anonymous credential systems that allow the user to convince a verifier of the possession of a certificate issued by a trusted authority anonymously and efficiently without interaction. A secure and efficient structure-preserving signature scheme is presented and a non-interactive anonymous credential system is constructed. The efficiency is analyzed and the security is proven in the context of identity authentication in an anonymous manner.
The paper on ‘An efficient hierarchical error recovery method for hybrid broadcast / communication networks’, gives a hierarchical error recovery method for hybrid mobile broadcast and communication networks as an alternative to retransmission based protocols for error recovery. Only the necessary data needed for error recovery is required to be transmitted when an error occurs, thereby reducing the data transmission requirements significantly. The performance evaluation has been studied in an experimental environment setup.