An energy-aware active smart card

Despite recent advances in smart card technology, most modern smart cards continue to rely on card readers for power and clocking, creating a potential security gap. In this paper, we present an energy-aware smart card architecture that operates using an embedded battery and crystal. This low-power VLSI system is continually active and provides enhanced security through periodic internal update when the card is detached from a reader. Our architecture achieves reduced power consumption by deactivating the majority of its circuitry, including an embedded microcontroller, for the vast majority of the card's lifetime. A proof-of-concept prototype implementation of the architecture has been developed including register-transfer-level and gate-level designs which have been synthesized to silicon. To permit extended operation for up to 18 months, critical design logic has been implemented using ultralow-power (adiabatic) circuit techniques.     

Power Transformer Differential Protection Based On Optimal Probabilistic Neural Network

In this paper, the optimal probabilistic neural network (PNN) is proposed as the core classifier to discriminate between the magnetizing inrush and the internal fault of a power transformer. The particle swarm optimization is used to obtain an optimal smoothing factor of PNN which is a crucial parameter for PNN. An algorithm has been developed around the theme of the conventional differential protection of the transformer. It makes use of the ratio of voltage-to-frequency and amplitude of differential current for the determination of operating condition of the transformer. The performance of the proposed heteroscedastic-type PNN is investigated with the conventional homoscedastic-type PNN, feedforward back propagation (FFBP) neural network, and the conventional harmonic restraint method. To evaluate the developed algorithm, relaying signals for various operating condition of the transformer, including internal and external faults, are obtained by modeling the transformer in PSCAD/EMTDC. The protection algorithm is implemented by using MATLAB.     

Modified Johnson–Cook material flow model for hot deformation processing

The need of a generalised flow curves considering strain (ε), strain rate ([(e)dot] dot{varepsilon } ) and temperature (T) is a primary requirement for material modelling related to several conventional and strategic mechanical processing to meet critical and non-critical engineering applications. The realistic coefficients of flow curves need to be obtained for such model. In the present study a modified Johnson–Cook (JC) material model has been proposed with physical significance. Six constants of this model can be obtained through the regression analysis. When compared to the JC model, proposed model is found to be more reliable for Al-2024 alloy.     

Investigations on a directly coupled piezoactuated tool feed system for micro-electro-discharge machine

A directly coupled piezoactuated tool feed mechanism is proposed and a prototype micro-electro-discharge machine (micro-EDM) is developed. The piezoactuator is used to feed the tool and also to sense the tool displacement from a reference position. The hysteresis behavior of the piezoactuator is also incorporated through an electromechanical model for estimating the actual tool displacement. Simulation results for piezoactuator displacement are compared with the experiment and a maximum error of 15% was observed. Further, in order to control the tool feed rate during machining, a tool feed controller based on the gap voltage feedback is developed. A contact-based measurement technique is integrated with the tool feed controller to measure the tool wear and the depth of material removed. Micromachining experiments have been conducted on a copper workpiece with copper and tungsten as tool materials. The experimental results obtained through the contact-based measurement technique are in agreement with the tool-displacement simulations with a maximum error of about 10%.     

Quadrature oscillator using grounded components with current and voltage outputs

This study proposes new third-order quadrature oscillator that provides several voltage and current outputs simultaneously. The circuit uses differential voltage current conveyors and grounded components, enjoys non-interactive frequency control and can be made resistor-less by using voltage-controlled differential voltage current conveyors. Non-ideal study and parasitic effects are also considered and their effects are discussed. The proposed theory is verified through PSPICE by good results.     

Improved performance of PEM fuel cell using carbon paper electrode prepared with CNT coated carbon fibers

Porous conducting carbon paper has been identified as the most suitable material to be used as a backing material for the fuel cell electrode. The surface of carbon fiber, the major constituent of the carbon paper was modified by: (1) removing the functional groups by heat cleaning process and (2) coating the non-functionalized carbon fiber with multi-walled carbon nanotubes (MWCNTs). This has a marked influence on the fiber–matrix interactions during later stages of processing of carbon paper that helped in controlling its various characteristic properties. Using the carbon paper formed with CNT coated carbon fiber as electrode, the maximum power density achieved from a unit fuel cell was found to be 783 mW/cm² as compared to 630 mW/cm² when the paper was formed with normal fiber.     

A Comparative Assessment of Metaheuristic Optimized Extreme Learning Machine and Deep Neural Network in Multi-Step-Ahead Long-term Rainfall Prediction for All-Indian Regions

Prediction of long-term rainfall patterns is a highly challenging task in the hydrological field due to random nature of rainfall events. The contribution of monthly rainfall is important in agriculture and hydrological tasks. This paper proposes two data-driven models, namely biogeography-based extreme learning machine (BBO-ELM) and deep neural network (DNN), to predict one, two, and three month-ahead rainfall over India (All-India and six other homogeneous regions). Three other data-driven models called ELM, genetic algorithm (GA)-based ELM, and particle swarm optimization (PSO)-based ELM are used to compare the performance of the proposed models. Firstly, partial autocorrelation function (PACF) is applied in all datasets to select the optimal number of lags for input to the models. Secondly, the wavelet-based data pre-processing technique is applied in selected optimal lags and feed to the proposed models for achieving higher prediction performance. To investigate the performance of proposed models, a non-parametric statistical test, Anderson–Darling’ Normality test, is performed in all India dataset. The wavelet-based proposed hybrid models show better prediction capability compared to optimal lag-based proposed models. This study shows the successful application of time-series data using proposed techniques (optimal lags-based BBO-ELM and wavelet-based DNN) in the hydrological field which may be used for risk mitigation from dreadful natural events.

     

A high throughput and low power ad-hoc wireless LAN protocol

Stations in IEEE 802.11 ad-hoc WLAN protocol exchange frames by contending for the channel and follow the binary exponential backoff for retransmitting the frames on collisions. This contention and collisions lead to low throughput and high power consumption. Although the stations can enter sleep mode, however they are forced to keep awake for full Beacon interval period if there are frames buffered for them. This long awake period leads to high power consumption. We have devised improved mechanisms that facilitate transmissions with reduced contention. We have defined a reservation period in which the senders reserve the channel by announcing the data frames to be transmitted to the Power Save (PS) stations. These announced frames are then transmitted collision-free in the following transmission period, leading to high throughput. The PS stations keep awake for short duration to receive these frames at predetermined periods, leading to high power saving. The mechanisms involve only software changes to the existing 802.11 protocol and can be implemented on the existing 802.11 WLAN cards. The average power consumption in our mechanisms is only 1/6th of the power consumed in the 802.11b protocol, with the stations consuming 84% lesser power. Our maximum throughput improved to 25% higher than the throughput of the 802.11b protocol. Our work also shows significant performance improvement over some related work in this area. Under conditions of optimal throughput, our improved protocol consumes 55% to 70% lesser power than SPAN protocol and has 3 to 5.8 times better Throughput/Energy consumption characteristics than DPSM protocol. Vimal K. Khanna (vimal_k@ieee.org) has nearly 21 years experience in the Communications Software industry. He has conducted research to develop innovative networking protocols and products in a range of domains, like TCP/IP suite, Dynamic Source Routing, IEEE 802.11 WLAN, ATM, Frame Relay, ISO/OSI protocols suite, SNMP, Ethernet, X.25/PAD, etc. His independently written papers have appeared in leading international archival networking journals. He has also developed innovative high performance techniques in the Operating Systems domain. His work on performance enhancements to Unix/Linux STREAMS kernel mechanisms has won wide acceptance in the industry and is cited on the Linux STREAMS (LiS) Open Source Community Website. He is on the Technical Editorial Board of “IEEE Communications” magazine (pub. New York) since 1999. He has acted as a reviewer for “IEEE Multimedia” magazine and multiple IEEE international conferences, like Globecom, ICC, etc. He has been an All India rank holder in the Indian Engineering Services Examinations and Silver Medallist in the All India Senior Secondary School Examinations (Class XII). He has been recipient of Ministry of Education All India Merit Scholarship and the National Talent Search Scholarship. Hari M. Gupta received the B.E. degree from the University of Roorkee, now the Indian Institute of Technology (IIT), Roorkee, in 1967, the M.Tech. degree from IIT, Kharagpur in 1969, and the Ph.D. degree from IIT Kanpur in 1974. He joined the faculty of Department of Electrical Engineering at IIT, Delhi in 1973 where he has been a professor since 1986. He has been the Dean of Undergraduate Studies, the Head of the Department of Electrical Engineering, and the Coordinator of Bharti School of Telecommunication Technology and Management at IIT, Delhi. He has held faculty appointments at McGill University, Montreal, Canada and Drexel University, Philadelphia, PA, USA. He has been an academic visitor to University of Maryland, College Park, MD, USA, the Media Lab, at Massachusetts Institute of Technology, Cambridge, MA, USA, the Swiss Federal Institute of Technology, Lausanne, Switzerland, Helsinki University of Technology, Helsinki, Finland, and several British Universities. His academic and professional interests are in communication systems, computer communication networks, multimedia systems and photonic information systems. Dr. Gupta has been India’s representative on the International Federation for Information processing (IFIP) Communications Committee. He is a Fellow of The Institution of Electronics and Telecommunication Engineers (IETE), The Institution of Engineers (India), and a Senior Member of Computer Society of India (CSI). He has been the Vice-President of the Systems Society of India, a Council Member of IETE, the Chairman of the Data Communication Division of CSI, and a Founder Member of the Association for Security of Information Systems (ASIS). Satyavardhan Maheshwari was born in Indore, India. He received M.S. degree from the Department of Electrical Engineering, IIT Delhi in 2003. He received B.E degree from the Department of Electrical Engineering, Devi Ahilya University, Indore. He joined Reliance Infocomm, India in 2003 as an R&D Engineer working on CDMA2000 system design. He is working on CDMA Base Station and planning in RF Engineering. His research area is IEEE 802.11 Ad-hoc Networks.     

Theoretical modeling of condensation of steam outside different vertical geometries (tube, flat plates) in the presence of noncondensable gases like air and helium

Condensation of steam coming out from the coolant pipe during a loss of coolant accident (LOCA) plays a key role in removing heat from the primary containment of the advanced nuclear reactor (ANR). The presence of large mass fractions of air (W_air = 0.25-0.9) and a small mass fraction of helium (W_He = 0.017-0.083) reduces the overall heat transfer coefficient (HTC) substantially. The present work emphasizes on the issue that modeling the diffusion of water-vapor through the gas-liquid interface is the key to give good predictions in HTC. In this, condensation conductivity and effective diffusivity plays a key role. Therefore, modifications have been made in the derivation for calculation of condensation conductivity in the case of steam-air mixture and effective diffusivity (in the case of multicomponent mixture). The model validation has been done with the experimental data of Dehbi et al. [Dehbi, A.A., Golay, M.W., Kazimi, M.S., 1991. National Conference of Heat Transfer AIChE Symposium Series, pp. 19-28] and Anderson et al. [Anderson, M.H., Herranz, L.E., Corradini, M.L., 1998. Experimental analysis of heat transfer within the AP600 containment under postulated accident conditions. Nucl. Eng. Des. 185, 153-172] and other analytical models available in the literature [Herranz, L.E., Anderson, M.H., Corradini, M.H., 1998a. The effect of light gases in noncondensable mixtures on condensation heat transfer. Nucl. Eng. Des. 183, 133-150; Herranz, L.E., Anderson, M.H., Corradini, M.L., 1998b. A diffusion layer model for steam condensation within the AP600 containment. Nucl. Eng. Des. 185, 153-172; Peterson, P.F., Schrock, Y.E., Kageyama, T., 1993. Diffusion layer theory for turbulent vapor condensation with noncondensable gases. J. Heat Transf., 115; Dehbi, A.A., Golay, M.W., Kazimi, M.S., 1991. National Conference of Heat Transfer AIChE Symposium Series, pp. 19-28]. Since the validations of the results were found satisfactory, the datasets [Dehbi, A.A., Golay, M.W., Kazimi, M.S., 1991. National Conference of Heat Transfer AIChE Symposium Series, pp. 19-28; Anderson, M.H., Herranz, L.E., Corradini, M.L., 1998. Experimental analysis of heat transfer within the AP600 containment under postulated accident conditions. Nucl. Eng. Des. 185, 153-172] have been compared with a wide range of subcooling and the operating pressures. An extensive comparison has been reported and the results predicted by the present model were found to be satisfactory.