Abhishek Agarwal

Sensitivity Enhancement of Electrolyte–Insulator–Semiconductor Sensors Using Mesotextured and Nanotextured Dielectric Surfaces

We report the fabrication of an electrolyte- insulator-semiconductor (EIS) device with an improved sensitivity brought about by texturization of the functionalized dielectric at the dielectric/electrolyte interface by electrostatic attachment of nanoparticle and mesoparticle. Improvement in sensitivities up to 42% over the nontextured (control) devices was obtained with SiO2 particles on SiO2 dielectric. The sensitivity was a function of the size of the particles with higher sensitivities being obtained with smaller particle sizes. The possible contributions of the chemical modification of the dielectric surface by the aminosilanes resulting in the modification of the surface charge, and of the physical modifications by particle texturization leading likely to enhancement of the surface densities of the active binding sites, were highlighted. A novel design for the EIS reservoir for possible improved circuit integration and manufacturability, involving a two-step reservoir in photoresist was demonstrated. This device was capable of characterizing sample volumes as small as 20 μL. A 2×1 and a 2×2 array was also demonstrated, which could be utilized for multianalyte detection.

Distributed Estimation in Homogenous Poisson Wireless Sensor Networks

In this paper we develop a homogenous Poisson point process based framework to characterize the performance of distributed estimation in wireless sensor networks. Such stochastic geometry based approaches have been shown to be robust compared to idealistic grid/ cluster models in wireless networks. We consider a fading wireless channel between the sensors and the Fusion Center (FC) and characterize the distributed estimation outage in a variety of scenarios. Towards this end we consider optimal maximal ratio combining (MRC) based coherent sensor transmission and derive closed form expressions for the outage probability. Further, we extend it to scenarios with fading channel phase based partial Channel State Information (CSI) and subsequently incorporate the effects of various path-loss models in large scale wireless sensor networks to derive bounds for the outage probability. Simulation results are presented to validate the performance of the proposed analysis.

Optimal Adaptive Modulation for QoS Constrained Wireless Networks with Renewable Energy Sources

In this paper we derive the optimal policy to minimize the average number of dropped packets for a delay constrained wireless node with a renewable energy source. The proposed framework employs adaptive modulation for transmission of the optimal number of packets towards satisfying the Quality of Service (QoS) constraints. This framework is formulated as a Markov Decision Process (MDP) which minimizes the long term packet drop rate. Further, we demonstrate that the optimal policy is monotone with respect to each of the joint state components of the MDP. Simulation results are presented to validate the monotone structure and superior performance of the proposed policy with respect to the existing schemes.

Prevalence of hypothyroidism in rheumatoid arthritis and its correlation with disease activity.

Objectives To analyse the prevalence of hypothyroidism in rheumatoid arthritis (RA) patients and to elucidate its correlation with disease activity. Methods A total of 52 RA patients were enrolled in this study. All patients were assessed fully clinically and underwent routine laboratory investigation including thyroid function testing. Results Hypothyroidism (defined as having a TSH level >4.20 μIU/mL) was observed in 20/52 (38.4%). Erythrocyte sedimentation rates (ESR) were found significantly elevated in patients with hypothyroidism compared to those without (36.3 ± 24.2 vs. 24.6 ± 9.0 mm/h). Disease activity parameters such as DAS-28-ESR, tender joint count; VAS scores were also significantly higher in the former. A significant correlation with serum TSH levels was observed with ESR and DAS-28-ESR. Conclusion Thyroid function test should be included in clinical evaluation of RA patients.

Optimal Scalable Video Scheduling Policies for Real-Time Single- and Multiuser Wireless Video Networks

In this paper, we present optimal video scheduling policies for layered scalable video streaming in delay-sensitive real-time fading mobile wireless video networks. Toward this end, we formulate the optimal video scheduling paradigm as a Markov decision process (MDP) for long-term video reward maximization, employing the scheduler state that is comprised of the fading channel, scalable video buffer status, decoder display slack, and large-scale wireless radio channel conditions. Further, we demonstrate structural properties of the optimal scheduling policy that significantly reduce the optimal policy computation. Subsequently, the above optimal video scheduling paradigm is extended to the context of a multiuser-fading-channel-based wireless video streaming scenario, where we develop an optimal index-based policy for user video scheduling, additionally incorporating fairness among users through a starvation-based approach. The presented optimal video scheduling policies are based on practical parameter values extracted from the Joint Scalable Video Model (JSVM)-based H.264 scalable video codec and, hence, are applicable in practice. Simulation results demonstrate improved video quality performance of the proposed optimal scalable video scheduling policies for single-user and multiuser scenarios.

Optimal Wake-up Scheduling for PSM Delay Minimization in Mobile Wireless Networks

In this work, we propose a Lloyd-Max based Sleep interval Determination (LMSD) algorithm towards optimal wake-up schedule computation to minimize the delay between data arrival and mobile device wake-up time, termed as the ON-OFF delay, for the Power Saving Mode in wireless networks. The proposed algorithm employs the probability distribution of the request-response time to compute the optimal sleep interval lengths for average wake-up delay minimization. Analytical results are derived to demonstrate convergence of the proposed LMSD algorithm. We also derive a novel information-theoretic bound to characterize the minimum average wake-up delay for a maximum threshold on the energy consumption for any generic wake-up schedule determination scheme. The LMSD algorithm is also seen to be computationally efficient due to the convexity of the average delay optimization objective. We compare the proposed approach with the existing schemes that improve the delay performance of the standard Binary Truncated Exponent algorithm and demonstrate that it achieves a lower average wake-up delay for a given average energy consumption while asymptotically achieving the delay bound.

Real time location estimation using active RFID system

The accuracy issues in the location prediction system using active RFID tags is addressed in this paper. First we present the location prediction accuracy in different environmental conditions. Later on, we propose a new technique to improve the prediction accuracy. The proposed technique is validated with measured data obtained under different propagation environments.

Tubercular monoarthritis of wrist

Tuberculosis (TB) has been a major health concern since decades, and millions continue to be afflicted with this disease. Extrapulmonary sites of TB must not be neglected as there is paucity of systemic manifestations and absence of distinct clinical features which delay its diagnosis and can lead to functional disability and severe infirmities. Osteoarticular TB is an infrequent form of the disease and monoarthritis of the wrist accounts for 1% of all cases of skeletal involvement. Hereby, we report a 45-year-old female patient with history of progressive pain and swelling of right wrist joint which is refractory to analgesics and anti-inflammatory drugs. She was diagnosed to have tubercular monoarthritis after synovial fluid analysis and radiographic findings. Standard antitubercular treatment for 6 months was given. The joint was salvaged after 9 months from the start of the treatment. Pain and swelling of joint were subsided and joint was rehabilitated with full range of motion and weight bearing.