Research Spotlight

Details

2018

Spotlight: We have started new investigations into various schemes of intrusive and non-intrusive stochastic finite element schemes for uncertainty evaluation in electromagnetic problems. In addition to the stochastic finite element method (SSFEM) developed earlier, we have adapted a Neumann method as an intrusive scheme and a least squared method as a non-intrusive scheme. Constraints and utility of these have been studied in various electromagnetic problems. In microwave group delay engineering, we have developed compact (12x15mm2) schemes for relatively high group delay (1.5ns) and low loss (1.5dB) at radio frequencies (2GHz). In addition, we have developed a passive radiometer system at low microwave frequencies. One of the interesting application is to detect the presence of a person at 2m distance while other sensing applications are being investigated. A mmwave 5G beam steering array is under development as part of the 5G test bed project.

Faculty Name: K J Vinoy

Spotlight: We have focused on two aspects of wireless networking for the Internet of Things: (i) development of throughput optimal, low delay, but low control information exchange, medium access control mechanisms for wireless data collection networks, and (ii) statistical characterisation of indoor wireless links, with a view towards deployment of indoor wireless networks for sensor interconnection. In the first area, for packet scheduling in a time slotted system of collocated nodes, we have developed a protocol that does not require any explicit exchange of queue length information; further, for non-collocated nodes, with path-graph dependence, we have studied reduced state scheduling. In the second area, we have been developing statistical path-loss models using packet transfers between several IEEE 802.15.4 devices placed in the building; we employ a linear regression approach, with data imputation to account for missing data due to packet loss.

Faculty Name: Anurag Kumar

Spotlight: To meet the growing demands of the data carrying capacity using optical carrier, various multiplexing schemes like frequency/wavelength, phase and amplitude are in practice. Recent addition is the spatial dimension of the carrier ie optical orbital angular momentum (OAM) . Data can be modulated on any one or combination of the above dimensions. As OAM has discrete infinite eigen basis it is possible to encode a large number of bits on a single photon or a beam. OAM can be used either in classical or in quantum communication depending on whether it is a beam of light or a single photon respectively. OAM is suitable for high density data for short distance transmission applications like data centers. Suitable devices are required to be designed to realize various functions in transmission and reception. Proposed the design of a sorter for 16 OAM modes using discrete optical components, when multiplexed OAM modes are received, the sorter will spatially resolve the modes.

Faculty Name: Shivaleelaesamudra Sharanappa

Spotlight: During the calendar year 2018, my research activities were in the following areas: (a) Information-theoretically secure key generation. My students and I have been involved in a long-standing collaboration on this topic with Prof. Chung Chan and his research group at the City University of Hong Kong. One important result we have obtained on this topic this year is a complete characterization of secret key capacity at asymptotically zero public discussion rate. (b) Secure distributed storage. In work with a BTech project student, V. Arvind Rameshwar, we gave explicit secrecy-capacity achieving coding schemes for all feasible parameter values of the MSR class of distributed storage codes. This paper has been shortlisted for a Best Paper Award at NCC 2019. (c) Coding for probabilistic forwarding over networks. My PhD student, Vinay Kumar, and I have developed a variety of tools to analyze how coding can help lower energy consumption for broadcast of data packets over networks.

Faculty Name: Navin Kashyap

Spotlight: (1) Proposal and experimental demonstration of a novel vertical, high gain, fast photo-detector with extremely high responsivity (>57000 A/W) and specific detectivity (>10^14 Jones). (2) Proposal and demonstration of enhanced (~15X) resistance switching by charge density wave driven phase change in 1T-TaS2. An experimental way to obtain the Mott gap in the commensurate phase has also been demonstrated using electrical measurements. (3) Proposal and demonstration of a backward diode with record high reverse rectification ratio using 2D material based heterojunction. (4) Proposal and demonstration of a self-powered, fast, high gain photodetector using ITO/WSe2/SnSe2 double heterojunction. (5) Determination of fundamental exciton linewidth, segregating both radiative and non-radiative components.

Faculty Name: Kausik Majumdar

Spotlight: 1. A Formal Model for Service Discovery Protocol(SDP) using SDL. https://dl.acm.org/citation.cfm?id=3056627 2.Specification of REST API Services for Modbus Protocol using Formal Technique. http://eudl.eu/doi/10.4108/eai.20-12-2017.153492 3.Context Aware Student Modelling in Ubiquitous Environment. http://www.iraj.in/journal/journal_file/journal_pdf/1-495-154079182533-36.pdf

Faculty Name: Anandi Giridharan

Spotlight: We have proposed an analytically based computational methodology that may become useful in designing multihop wireless networks to meet Quality of Service requirements. We have extended existing loss networks theory in an approximate analytical model based on the link independence approximation, to predict flow blocking probabilities, and average non real-time flow sojourn times and average real-time packet end-to-end delays. The time-average power available for transmission on a communication channel is limited. Higher instantaneous power may be used when the data backlog in the transmitter buffer is larger, in order to increase the instantaneous transmission rate and reduce backlog. We have modelled and optimised the transmission system as an M/M/1 data packet queue with queue-length dependent packet transmission rate and packet admission rate, where the time-average transmission power is upper limited and the time-average packet throughput is lower limited.

Faculty Name: Utpal Mukherji

Spotlight: Theoretical contributions: Provided insights on the difficulties related to multidimensional auctions and how to overcome them in some special cases – when does the dual method work, when does virtual validation method work; provided insights on why switching costs disappear while sleep-cycling densely deployed base stations for energy consumption reduction; wrote a survey of algorithms for a large class of optimisation problems that arise in resource allocation on wireless networks; and provided insights on why side-information is enormously useful in detecting a single community from noisy information (as compared to two communities). Practical AI for social good: developed automated tools for IoT network deployment; developed a Digital Twin and an Industrial IoT platform for understanding the happenings in an SMT manufacturing line; identified metrics for assessing city-scale water distribution inequity; and proposed double-auction mechanisms to enable mobile data offloading.

Faculty Name: Rajesh Sundaresan

Spotlight: (a) Integrated Optic Double ring resonator based pressure and acceleration sensors (b) High speed optical modulators using Lithium Niobate on Insulator substrate (c) Single-and multidimensional integrated optic photon sources for quantum communication (d) Sub-nanometer narrow bandwidth gratings using deeply etched SOI rib waveguides

Faculty Name: Srinivas Talabattula

Spotlight: We conducted research on hybrid 2D/3D electromagnetic solvers for application in Signal Integrity analysis of high speed servers. The project is funded by Uchatar Avishkar Yojona. We conducted research on radio-frequency imaging for breast cancer analysis. Our work focuses on reconstruction algorithms for the measured antenna data, a process also known as inverse electromagnetic solution. We have proposed a Hierarchical Levenburg-Marquardt algorithm and a hybrid machine-learning and optimization process. We started a company called Simyog Technology Pvt. Ltd. incubated by SID, IISc. Simyog focuses on enabling agile processes in hardware development. Currently we are focused on Simulation of EMI/EMC issues in Automotive Electronics.

Faculty Name: Dipanjan Gope

Spotlight: Research work focused in the area of resonant enhancement of nonlinear optical interaction with dielectric nanostructures. Resulted in the demonstration of multifold enhancement of third-harmonic generation- THG from amorphous-Si nanodisk arrays. Reported the first spatio-spectral and intensity dependent THG from a-Si nanodisk arrays in Optics Letters journal in November 2018. In this work, we reported the first intensity dependent change in image contrast in the THG microscopy images. Continuing on this work with the demonstration of four-wave mixing in silicon zero-contrast grating structures. Also working on fluorescence enhancement in Silicon Nitride medium contrast grating structures. Also started a collaborative project with Dr. Ramray Bhat, at MRDG, working on collagen gel second-harmonic generation microscopy in the presence of various proteo-glycans (Chondotin sulfate and Dermatin sulfate). Clear changes in the organization of the polymer structure of collagen.

Faculty Name: Raghunathan Varun

Spotlight: Theory research: 1. Developed a new theoretical framework to capture increase in difficulty of solving statistical problems due to local information constrained posed on samples. This general approach has been applied to several specific problems and has led to many submissions. 2. A new method for showing lower bounds for coding problems with distributed, interactive communication. This method was applied to show a so-called strong converse result for the wiretap channel, a problem that was open for decades, and to obtain a sharp direct product result for communication complexity. Implementation/testbed based R&D: 1. Fast handover for WiFi using real-time location estimation. An intelligent handover algorithm was implemented and deployed on a testbed outside the ECE department. 2. Developed algorithms for real-time compression of PMU data in smart grids and deployed on hardware. 3. Algorithms for AQI sensor calibration and high spatio-temporal density air quality monitoring.

Faculty Name: Himanshu Tyagi