Department of Electrical Engineering

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IIT Jodhpur

In this paper, we propose a prediction algorithm that uses adaptive predictor structures for loss less video coding. The proposed encoder finds cross-correlation coefficient between current frame and motion compensated previous frame and classifies the coefficient value into a small number of bins. For general videos, we propose four bins and associate different predictor structures with each of the bins. Similarly for medical videos, numbers of bins are three and each of these bins is associated with different predictor structures. Performance of our method is compared with the fixed predictor structure used in practice and found that the proposed method not only gives better prediction performance but it is computational efficient as compared to fixed predictor structure. © 2012 IEEE.

World University root node

Data Compression Conference Proceedings

Adaptive predictor structures for lossless compression of videos

The paper presents the well-established spectral analysis approach to diagnose the physiological state of an unborn using phonocardiography. The separation of systole and diastole segments from a complete cardiac cycle of the fetus is carried out through envelope detection and threshold decision. The averaged periodogram is used for estimating both the spectral distribution and the dominant peak of the fetal heart sound signal. The current study clearly demonstrates that the fetal heart sound signals and their frequency spectra from the pathological subjects exhibit markedly different characteristics from those of healthy subjects. It can be safely concluded that the frequency spectrum and its contents of fetal cardiac sounds are specifically related to the health of the fetus. The importance of this study lies in the fact that with this approach, recognition and accurate estimation of systole and diastole periods of the fPCG signal as well as the quantification of their frequency contents can be performed very efficiently. Copyright © 2012 Inderscience Enterprises Ltd.

International Journal of Medical Engineering and Informatics

Spectral analysis of fetal heart sounds in healthy and pathological subjects

It is well known that the straight forward application of controller design methods to two-time-scale systems is susceptible to numerical ill-conditioning and stiffness problems. However, it has been demonstrated in this paper that the presence of time-scales can be exploited for achieving better computational efficiency in case of the design of controllers based on periodic output feedback and fast output sampling principles. In particular, an approach for design of periodic output feedback and fast output sampling controllers for a two-time-scale system by decomposition into a slow and a fast subsystem problems, has been presented. These smaller order problems are then separately solved and the results thus obtained for the slow and fast subsystems are combined to obtain the solution of the original design problems. The procedure has been illustrated with the help of a very simplified nuclear reactor model. Copyright © 2011 John Wiley and Sons Asia Pte Ltd.

Asian Journal of Control

Design of periodic output feedback and fast output sampling based controllers for systems with slow and fast modes

The study proposes a method to design a non-linear sliding surface to achieve better transient response for a class of single-input and single-output (SISO) non-linear uncertain system represented in a Brunowsky canonical form. The proposed surface can also be used for linear uncertain systems with matched perturbations. The proposed surface increases the damping ratio of the closed-loop system from its initial low value; as the output approaches the setpoint from its initial value. Initially, the system is lightly damped resulting in a quick response and as the output approaches the setpoint, the system is overdamped to avoid overshoot. The existence of sliding mode is proved and a new control law is proposed to enforce sliding motion. The scheme is able to achieve low overshoot and short settling time simultaneously which is not possible with a linear sliding surface. To ease the synthesis of the non-linear surface, linear matrix inequalities-based algorithm is proposed. Effectiveness of the proposed scheme is illustrated by the simulation results. © 2011 The Institution of Engineering and Technology.

IET Control Theory and Applications

Non-linear sliding surface: Towards high performance robust control

In the present work, we report the growth of wurtzite InN epilayers on GaN/Si (1 1 1) substrate by plasma-assisted molecular beam epitaxy (PAMBE). The growth parameters such as indium flux, substrate temperature and RF power affect the crystallographic and morphological properties of InN layers, which were evaluated using high resolution X-ray diffraction (HRXRD) analysis and atomic force microscopy (AFM). It is found that excess indium (In) concentrations and surface roughness were increased with increase in In flux and growth temperature. The intensity of HRXRD (0 0 0 2) peak, corresponding to c-axis orientation has been increased and full width at half maxima (FWHM) has decreased with increase in RF power. It was found that highly c-axis oriented InN epilayers can be grown at 450 °C growth temperature, 450 W RF power and 1.30 × 10-7 mbar In beam equivalent pressure (BEP). The energy gap of InN layers grown by optimizing growth conditions was determined by photoluminescence and optical absorption measurement. © 2011 Elsevier B.V. All rights reserved.

Journal of Alloys and Compounds

Indium flux, growth temperature and RF power induced effects in InN layers grown on GaN/Si substrate by plasma-assisted MBE

This paper describes a substrate integrated waveguide (SIW) based filter at K band frequency on silicon substrate. TMAH etching is used to form the via-holes for SIW cavities. Simulations and comparison of TMAH and Deep reactive ion etching (DRIE) etched cavity has been presented. A micro- machined filter is made from rectangular cavities integrated into a silicon substrate and is fed by coplanar waveguide (CPW) transmission-lines through current probes. Simulated filter using TMAH etching shows insertion loss of 0.29dB and return loss of 21.96 dB. © 2012 IEEE.

2012 International Conference on Computing, Electronics and Electrical Technologies, ICCEET 2012

Silicon micromachined K-band filters

This paper presents a novel approach to monolithically implement a planar multiport radio-frequency (RF) microelectromechanical systems (MEMS) T-type switch. T-type switches are used as building blocks of redundancy switch matrices used in space telecommunication. The T-type switch performs signal routing in three operational states. Two of them are boundary states while the other one is a crossover state. The proposed design uses a series metal contact clamped-clamped beam SPST switches, four port psi junctions and a RF crossover. The simulated results for the entire T-type switch demonstrate an insertion loss of -0.48dB and isolation better than -22.12dB for all states for frequencies up to 25GHz. The use of eight switches instead of twelve makes T-type switch compact. This improves the reliability and compactness of the redundancy switch matrix. The switch gives excellent RF performance near X-band and Ku-band which is the most widely used frequency range for satellite communication. © 2012 Pillay Engineering College.

IEEE-International Conference on Advances in Engineering, Science and Management, ICAESM-2012

RF MEMS compact T-type switch design for switch matrix applications in space telecommunication

System-level signal integrity (SI) and power integrity (PI) problems are taken into account. System-level simulation of high-speed systems with effect of external environment is described. SI and PI issues with complete analysis of package, board, termination, squid card, and decoupling network are shown. Common problems of simulations-passivity violation, stability, causality, and interoperability, are also discussed.

IETE Technical Review (Institution of Electronics and Telecommunication Engineers, India)

Signal integrity and power integrity issues at system level

T{\'{e}}l{\'{e}}com ParisTech

Rate-Reliability-Complexity limits in ML and lattice based decoding for MIMO, multiuser and cooperative communications

This paper presents the design and experimental implementation of second order sliding mode (SOSM) control using super twisting algorithm to minimize structural vibration. A linear dynamic model of the smart cantilever beam is obtained using online recursive least square method and information filter is used for state estimation. A digital control system that consists of simulink modeling software and dSPACE 1104 controller board has been used for implementation. The effectiveness of the controllers for rejecting uncertainty is shown experimentally by exciting the structure at resonance with added tip mass and at elevated temperatures. © 2012 IEEE.