National Institute of Technology, Meghalaya

About: National Institute of Technology, Meghalaya is a education organization based out in Shillong, India. It is known for research contribution in the topics: Control theory & Electric power system. The organization has 503 authors who have published 1062 publications receiving 6818 citations. The organization is also known as: NIT Meghalaya & NITM.

An energy-efficient wireless communication scheme using Quint Fibonacci number system

Abstract: In this paper, an energy-efficient communication scheme for low-power wireless networks is proposed which is based on encoding the messages in a new number system, called the Quint Fibonacci number system QFNS, followed by using a concept of Silent Communication. The proposed scheme employs a simple hybrid modulation/demodulation technique using non-coherent FSK and ASK, which leads to the design of a low-power, low-cost wireless communication system that will particularly be suitable for remote/rural healthcare applications. We show that with Additive White Gaussian Noise AWGN in channel, our scheme offers about 39.6% energy savings at the transmitter and about 52% energy savings at receiver on an average over the conventional Binary Frequency Shift Keying BFSK system, for equal likelihood of all possible strings of binary messages. However, simulation results with different types of messages from various healthcare and agricultural sensor data applications show that we get about 29.82% to 36.23% energy savings at the transmitter and about 56.42% to 64.29% energy savings at the receiver over conventional BFSK.

Towards a Cost Metric for Nearest Neighbor Constraints in Reversible Circuits

Abstract: This work in progress report proposes a new metric for estimating nearest neighbor cost at the reversible circuit level. This is in contrast to existing literature where nearest neighbor constraints are usually considered at the quantum circuit level. In order to define the metric, investigations on a state-of-the-art reversible to quantum mapping scheme have been conducted. From the retrieved information, a proper estimation to be used as a cost metric has been obtained. Using the metric, it becomes possible for the first time to optimize a reversible circuit with respect to nearest neighbor constraints.

Medium bandgap copolymers based on carbazole and quinoxaline exceeding 1.0 V open-circuit voltages

Abstract: Open-circuit voltage (VOC) is an important parameter in determining the performance of polymer solar cells (PSCs). Given the desire for superior VOC values in PSCs, we have designed and synthesized a series of ‘medium bandgap’ donor–acceptor (D–A) copolymers containing carbazole (Cz) and quinoxaline (Qx) (PCzDT-Qx, PCzDT-fQx, and PCzDT-ffQx). As a result of their deep-lying HOMO levels (−5.45 to −5.61 eV), high VOC values are achieved in PSCs with the resulting copolymers, despite the expense of short-circuit current density (JSC) and fill factor (FF) parameters. In this study, in addition to the best power-conversion efficiency (PCE) of up to 4.03% from PCzDT-fQx-based on PSCs, we have demonstrated a VOC value exceeding 1.0 V with PSCs of PCzDT-ffQx, which is among the highest VOC values achieved to date. Moreover, a comprehensive investigation on the mechanism of charge recombination and transport characteristics can determine a clear structure–property correlation in this class of molecules, which is helpful for designing better materials with maximum VOC without scarifying other key photovoltaic parameters.

Determining Duty Cycle and Beacon Interval with Energy Efficiency and QoS for Low Traffic IEEE 802.15.4/ZigBee Wireless Sensor Networks

Abstract: Wireless Sensor Networks (WSNs) are becoming integral part of today’s world due to their wide range of applications WSNs are used in industrial applications such as factory automation and control, environmental monitoring etc which are of low data rate but demand Quality of Service (QoS) in terms of reliability and timeliness along with energy efficiency A WSN’s lifetime depends on the rate of consumption of energy by the sensors One way to save energy is the judicious use of active and inactive periods in the duty cycle based Medium Access Control (MAC) protocols The slotted IEEE 802154 MAC protocol provides for it The duty cycle mechanism however has the potential to affect the performance of the network in terms of QoS due to possible higher packet collision rate in the active periods with reduction in duty cycle For such applications an appropriate selection of duty cycle that maintains the required QoS is vital while ensuring longevity of the network Another important MAC parameter that has a role in the performance of WSNs based on IEEE 802154/ ZigBee is the length of the Beacon Interval (BI) In this paper we present the results of our simulation experiments for determining appropriate Duty Cycle and Beacon Interval that maximizes energy efficiency while ensuring the QoS requirements of the application

Power system harmonic parameters estimation using ADALINE-VLLMS algorithm

Abstract: This paper proposes a combined adaptive linear neural network and variable leaky least mean square (ADALINE-VLLMS) algorithm for harmonic parameters estimation in a distorted power signal. VLLMS method applies a variable leaky adjustment technique for avoiding drifting of the parameter involved in the estimation. Moreover, a variable step-size is proposed to have faster convergence than conventional least mean square (LMS) algorithm. Computer simulations show that the proposed ADALINE-VLLMS method gives better performance than the ADALINE-LMS method.