Heritage Institute of Technology

About: Heritage Institute of Technology is a based out in . It is known for research contribution in the topics: Support vector machine & Transconductance. The organization has 581 authors who have published 1045 publications receiving 8345 citations.

Optimization of Small-Signal Model of GaN HEMT by Using Evolutionary Algorithms

Abstract: In this letter, a new evolutionary algorithm-based method for the optimization of intrinsic elements of small-signal model (SSM) of GaN HEMT devices is presented. The method uses a unique search space exploration strategy for evolutionary algorithms to obtain an optimized compact SSM from the extracted parameter and measured S-parameters. The validity of the method is verified by comparing the measured S-parameter data of a $2 \times 0.1 \times 50 \,\,{\mu \text {m}}^{2}$ GaN/Si HEMT and a $4 \times 0.1 \times 75 \,\,{\mu \text {m}}^{2}$ GaN/SiC HEMT in the frequency range of 1 to 30 GHz. The modeled data and measured data are in good agreement.

Development and performance analysis of a low-cost MEMS microphone-based hearing aid with three different audio amplifiers

Abstract: In this paper, MEMS-based capacitive microphone and low-cost amplifier are designed for low-cost power-efficient hearing aid application. The developed microphone along with the associated circuitry is mounted on a common board in the form of pocket-type (body-worn) device. The designed microphone consists of a flexible circular silicon nitrite (Si3N4) diaphragm and a polysilicon-perforated back plate with air as dielectric between them. The incident acoustic waves on the sensor cause deflection of the diaphragm to alter the air gap between the perforated back plate (fixed electrode) and the diaphragm (moving plate) which causes a change in capacitance. The acoustic pressure applied to the microphone is from 0 to 100 Pa for an operating range of 100 Hz–10 kHz which corresponds to the audible frequency range in case of human beings. The main purpose of this work is to increase the longevity of battery used in conventional hearing aids. The designed MEMS microphone with Si3N4 diaphragm is capable of identifying acoustic frequencies (100 Hz to 10 kHz) which correspond to a specific change in absolute pressure from 0 to 100 Pa for 2-micron-thick diaphragm with a sensitivity of about 0.08676 mV/Pa. The design of the sensor and the characteristics analysis are performed in FEM-based simulation software, which are later validated in real time. The prototype is designed using MEMS microphone and low-cost amplifier ICs with biasing components in the form of pocket-type (body-worn) hearing aid. In order to study the performance of proposed device, three different market-available amplifiers with controllable gain are used. Finally, the performance of the hearing aid is studied through audio spectrogram analysis to choose the best-suited amplifier among the three.

Collaborative Recommendations using Hierarchical Clustering based on K-d Trees and Quadtrees

Abstract: Majority of the e-commerce sites implement Recommender Systems (RS) to help users navigate through the large search space and assist their decision making process by suggesting products that the us...

Multi-warehouse partial backlogging inventory system with inflation for non-instantaneous deteriorating multi-item under imprecise environment

Abstract: In this study, we explored a multi-item inventory model for non-instantaneous deteriorating items under inflation in fuzzy rough environment with multiple warehouse facilities, where one is an owned warehouse and others are rented warehouses with limited storage capacity. Due to a number of uncertainties in the environment, the various expenditures and coefficients are considered as a fuzzy rough type. The objective and constraints in fuzzy rough are made deterministic using Tr–Pos chance constrained technique. The demand of items is considered as stock dependent, and deterioration of items is assumed to be constant over time. The model allows shortages in owned warehouse subject to partial backlogging. The purpose of this study is to find the retailer’s optimal replenishment policies to maximize the total profit. To illustrate the proposed model and also test the validity of the same, a numerical example is solved using the Mathematica-8.0 software. Sensitivity analysis is also performed to study the impact of important parameters on system decision variables, and its implications are discussed.