North Eastern Regional Institute of Science and Technology

About: North Eastern Regional Institute of Science and Technology is a education organization based out in Itanagar, India. It is known for research contribution in the topics: Population & Raman spectroscopy. The organization has 813 authors who have published 1429 publications receiving 16122 citations.

Impact of black hole attack on reliability of mobile ad hoc network under DSDV routing protocol

Abstract: There has been considerable use of many devices that run on wireless infrastructure such as the mobile ad hoc network (MANET). MANET has become a preferred means of communication in recent times. The reliability and security aspects of MANET need to be investigated further to provide robust and reliable communication. However, current literature shows that little work has been done towards reliability analysis of MANET. The paper gives the reliability analysis of MANET with black hole attack running DSDV routing protocol. NS-2.35 simulation software is used to analyse the impact of black hole attack on the reliability of MANET under destination sequenced distance vector (DSDV) routing protocol. Simulation result shows that the reliability of MANET under multiple black hole attack is lower than the reliability of MANET under single black hole attack in DSDV routing protocol.

Harmonic minimization in multilevel inverters using numerical series technique

Abstract: Cascaded multilevel inverters have received considerable attention from industries and researchers for high voltage and medium power applications. Numerous modulation and harmonic minimization techniques have been suggested to reduce the total harmonic distortion (THD) in multilevel waveforms. Recently a harmonic minimization technique based on numerical series has been reported. This technique was investigated for multilevel waveforms having different voltage levels and the resulting THDs were found to be satisfactory. However, no experimental result of this technique is available as yet. This paper presents the hardware design of a single-phase 50 Hz, 230 V, 84 W cascaded inverter fed by a single 12 V dc source. Wave-stepping was used to generate a 9-level voltage waveform with only two H-bridge cells. The concept of open drain mode of MOSFETs was used to drive the high side switches. Experimental results are presented to validate the feasibility of the approach.

A review on accelerating scientific computations using the Conjugate Gradient method

Abstract: Conjugate Gradient method is a very efficient iterative method for solving large systems of equations arising from real life scientific computing applications. In this paper we present the Conjugate Gradient method and its variants in brief. We also present a comparative analysis of implementations of this method on various platforms like FPGAs, GPUs etc which are suitable for High Performance Computing.

Introspection Into Reliability Aspects in AlGaN/GaN HEMTs With Gate Geometry Modification

Abstract: Reliability enhancement of AlGaN / GaN HEMT is a significant thrust area due to rapidly improving material and processing technology. In this paper, a detailed analysis of gate–shaped AlGaN / GaN HEMT with field plate is presented. Although AlGaN / GaN HEMT with field–plate is well known, its blending with gate–shaping leading to a more robust and reliable behaviour is described in this paper. It is observed that the threshold voltage and transconductance invariably remain constant for various combinations of gate–shaped and field plate placements. The threshold voltage for all the devices are found to be – 5.8 V. The peak transconductance for the devices without field plate and with field plate is $\sim ~0.16$ S/mm and $\sim ~0.15$ S/mm, respectively. Apart from leakage current, the electric field also gets mitigated for both gate–shaped and field–plated devices by $\sim ~45$ % and $\sim ~68$ %, respectively. The moderation in electric field further assists in the reduction of electron temperature for gate–shaped and field–plated structures by $\sim ~12$ % and $\sim ~85$ %, respectively. Additionally, breakdown voltage increases for the gate–shaped devices to 133 V as compared to 120 V of conventional devices without field plate. Significant reduction in leakage current, electric field, and electron temperature is accompanied by a minor increment in capacitance for the field–plated structure, hence, the proposed structure is expected to enhance reliability of the device. Thus, it is anticipated that the proposed devices with enhanced reliability would be a step ahead of conventional devices and would find major applications in high power domain.

Dynamic and Static Characteristics of Wavy Annular Seals in Turbulent Flow

Abstract: This paper presents results of a theoretical analysis to determine the leakage flow and dynamic characteristics of circumferential wave geometry annular seals using turbulent lubrication theory. Turbulent lubrication equations based on an eddy viscosity model have been used to develop the turbulent Reynolds equation. Convective fluid inertia effects have been incorporated using the perturbation approach in turbulent lubrication. To determine the dynamic characteristics i.e. stiffness, damping and whirl ratio, perturbation theory for small amplitude vibration of the journal center has been adopted. In general, it has been found that circumferential wave geometry improves the performance of the annular seal at higher speeds and increases in the L/D and taper ratios.