Delay Optimal Event Detection on Ad Hoc Wireless Sensor Networks

We consider a small extent sensor network for event detection, in which nodes take samples periodically and then contend over a {\em random access network} to transmit their measurement packets to the fusion center. We consider two procedures at the fusion center to process the measurements. The Bayesian setting is assumed; i.e., the fusion center has a prior distribution on the change time. In the first procedure, the decision algorithm at the fusion center is \emph{network-oblivious} and makes a decision only when a complete vector of measurements taken at a sampling instant is available. In the second procedure, the decision algorithm at the fusion center is \emph{network-aware} and processes measurements as they arrive, but in a time causal order. In this case, the decision statistic depends on the network delays as well, whereas in the network-oblivious case, the decision statistic does not depend on the network delays. This yields a Bayesian change detection problem with a tradeoff between the random network delay and the decision delay; a higher sampling rate reduces the decision delay but increases the random access delay. Under periodic sampling, in the network--oblivious case, the structure of the optimal stopping rule is the same as that without the network, and the optimal change detection delay decouples into the network delay and the optimal decision delay without the network. In the network--aware case, the optimal stopping problem is analysed as a partially observable Markov decision process, in which the states of the queues and delays in the network need to be maintained. A sufficient statistic for decision is found to be the network-state and the posterior probability of change having occurred given the measurements received and the state of the network. The optimal regimes are studied using simulation.Comment: To appear in ACM Transactions on Sensor Networks. A part of this work was presented in IEEE SECON 2006, and Allerton 201

A study on lipoprotein(a) in health and type-2 diabetes mellitus

Background: Increased lipoprotein (a) [Lp (a)] concentrations are predictive of coronary artery disease (CAD). Type 2 diabetes mellitus also leads to dyslipidemia, which are known risk factors for CAD. This study was designed to investigate the levels of Lp (a) in type 2 diabetic patients and their association with healthy controls and glycemic control.Methods: The study included 87 subjects out of which 20 were healthy volunteers. The remaining 67 were patients with type 2 diabetes from which 3 groups were formed 23 formed newly diagnosed group while those on treatment for diabetes were 44 out of which 22 were type 2 diabetics on oral hypoglycemic agents and the other 22 were type 2 diabetics on insulin. Individuals suffering from HT, renal disease, liver disease, thyroid dysfunction, nephrotic syndrome & cardiac disease, alcoholics, smokers or on lipid lowering drugs were excluded. Statistical analysis was done using the pearsons correlation.Results: Lp(a) levels were found to be significantly increased in the diabetic group irrespective of whether newly diagnosed not on treatment or old cases on treatment with oral hypoglycemic agents or insulin. Lp(a) levels showed no correlation to the degree of glycemic control in these patients. Lp(a) positively correlates with total cholesterol, LDLc and negatively with TGL and VLDLc in diabetics while it does not correlate with any of the lipid parameters in controlsConclusions: The results of the present study suggest that Lp(a) levels are increased in type 2 diabetic patients. The elevated Lp(a) levels do not reflect the glycemic status and correlates with increase in total cholesterol and LDLc suggesting similar metabolic pathways and the genetic connection for LDL and Lp(a)

Improved Memoryless RNS Forward Converter Based on the Periodicity of Residues

The residue number system (RNS) is suitable for DSP architectures because of its ability to perform fast carry-free arithmetic. However, this advantage is over-shadowed by the complexity involved in the conversion of numbers between binary and RNS representations. Although the reverse conversion (RNS to binary) is more complex, the forward transformation is not simple either. Most forward converters make use of look-up tables (memory). Recently, a memoryless forward converter architecture for arbitrary moduli sets was proposed by Premkumar in 2002. In this paper, we present an extension to that architecture which results in 44% less hardware for parallel conversion and achieves 43% improvement in speed for serial conversions. It makes use of the periodicity properties of residues obtained using modular exponentiation

FIR Filter Implementation by Efficient Sharing of Horizontal and Vertical Common Sub-expressions

No abstract availabl

MICROBIAL ENZYMATIC REDUCTION OF IRON NANOPARTICLES FOR THE CONTROL OF HUMAN PATHOGENS, STAPHYLOCOCCUS AUREUS, AND SALMONELLA TYPHI

Objective: The objective of this study was to synthesis, characterize, and evaluation of antimicrobial potential of iron nanoparticles (Fe NPs) using Serratia marcescens. Methods: Fe NPs were fabricated by microbial enzyme using ferric chloride as an agent of reduction and stabilization. Fe NPs formation and their elemental nature were confirmed by ultraviolet (UV)-absorption spectroscopy and energy dispersive X-ray spectroscopy, respectively. The morphology of Fe NPs was characterized by a scanning electron microscope (SEM). Functional groups of biomolecules associated with Fe NPs were inferred from characteristic Fourier transform infrared (FTIR) spectroscopy peaks. The antibacterial activity is determined by the disc diffusion method. Results: Synthesized Fe NPs exhibited characteristic UV-absorption spectrum peaks at 263nm. FTIR spectroscopy peaks of Fe NPs, 3411.66, 1629.16, 1039.63, and 601.90 cm−1 corresponds to carbonyl, disulfides, and ethers groups. SEM study demonstrated that the average size was from 200nm with interparticle distances. The crystalline nature of Fe NPs was confirmed from the X-ray diffraction peaks analysis. The intense diffraction peaks due to Fe NPs at 16.32, 22.56, 35.54, 41.08, 52.36, 61.42, 66.42, 78.1, and 85.08. Corresponding to the 110, 150, 200, 430, 550, and 950 facets of the face-centered cubic crystal structure conformed to the Joint Committee on Powder Diffraction Standards: 89-3722 of iron. Antimicrobial activity of Fe NPs against tested Gram-positive and negative bacterial strains showed significant inhibitory zones. Conclusion: The inhibitory zones obtained in the present study reveal that the Fe NPs can act as a good antibacterial agent

Proportional Fair Coding for Wireless Mesh Networks

We consider multi–hop wireless networks carrying unicast flows for multiple users. Each flow has a specified delay deadline, and the lossy wireless links are modelled as binary symmetric channels (BSCs). Since transmission time, also called airtime, on the links is shared amongst flows, increasing the airtime for one flow comes at the cost of reducing the airtime available to other flows sharing the same link. We derive the joint allocation of flow airtimes and coding rates that achieves the proportionally fair throughput allocation. This utility optimisation problem is non–convex, and one of the technical contributions of this paper is to show that the proportional fair utility optimisation can nevertheless be decomposed into a sequence of convex optimisation problems. The solution to this sequence of convex problems is the unique solution to the original non–convex optimisation. Surprisingly, this solution can be written in an explicit form that yields considerable insight into the nature of the proportional fair joint airtime/coding rate allocation. To our knowledge, this is the first time that the utility fair joint allocation of airtime/coding rate has been analysed, and also, one of the first times that utility fairness with delay deadlines has been considered

EVALUATION OF A FINANCIAL DECISION SUPPORT SYSTEM IN BUSINESS EDUCATION: AN EXPERIMENTAL STUDY

This study explores the use of computers in business education and its impact on the performance of students. A controlled experimental study has been carried out to determine the differences in performance of students in a computer assisted mstruction (CAI) group with that of a control group. It investigates the relationship between performance and various student-specific characteristics such as aptitude, attitude, sex, domain experience, domain expertise, and system experience. The relationships b between attitude towards CAI, fulfillment of expectations, and satisfaction with the system and course have also been explored. The results indicate that CAI has favorable effects on students\u27 performance and that personal attributes have relatively less important roles to play

Searching for pitch invariant representations in auditory cortex [oral presentation]

Pitch constancy relates to perceiving the same pitch from tones with differing spectral shapes and is one key criteria for identifying a pitch selective neural representation in auditory cortex. Here we used an event-related potential (ERP) adaptation study and a behavioural task (target same/different) to investigate whether pitch coding is invariant to changes in timbre. Adaptation is observed as a decrease in N100-P200 when the same stimulus is repeated because overlapping neuronal populations encode the stimulus. Reduced adaptation indicates that new neuronal populations are recruited to encode a change in an acoustic feature of interest (i.e. pitch, timbre or both). If neurons are selective to pitch (invariant to timbre), reduced adaptation should occur for pitch changes only. If selective to both (non-invariant to timbre), reduced adaptation should occur for pitch and timbre changes. Similarly, stimulus discrimination during the behavioural task should not require any additional processing resources if neurons are selective to pitch only, and hence reaction times and accuracy should be equivalent across conditions. If neurons are selective to both pitch and timbre, longer reaction times and poorer accuracy should be observed for timbre changes. We found reduced adaptation in the N100-P200 and increased reaction times and poorer accuracy for timbre changes. This suggests that neurons in auditory cortex are selective to both pitch and timbre, i.e. pitch coding is non-invariant to timbre. This supports recent evidence suggesting interdependence between pitch