An energy-efficient permutation routing protocol for single-hop radio networks

A radio network (RN) is a distributed system where each station or node is a small hand-held commodity device called a station. Typically, each station has access to a few channels for transmitting and receiving messages. By RN(p, k), we denote a radio network with p stations, where each station has access to k channels. In a single-hop RN, every station is within the transmission range of every other station. Each station consumes power while transmitting or receiving a message, even when it receives a message that is not destined for it. It is extremely important that the stations consume power only when it is necessary since it is not possible to recharge batteries when the stations are on a mission. We are interested in designing an energy-efficient protocol for permutation routing, which is one of the most fundamental problems in any distributed system. An instance of the permutation routing problem involves p stations of an RN, each storing n/p items. Each item has a unique destination address which is the identity of the destination station to which the item should be sent. The goal is to route all the items to their destinations while consuming as little energy as possible. We show that the permutation routing problem of n packets on an RN(p, k) can be solved in 2n/k+(p/k)/sup 2/+p+2k/sup 2/ slots and each station needs to be awake for at most 6n/p+2p/k+8k slots. When k/spl Lt/p/spl Lt/n, our protocol is more efficient, both in terms of total number of slots and the number of slots each station is awake compared to a previously published protocol by Nakano et al. (2001).     

Random-data perturbation techniques and privacy-preserving data mining

Privacy is becoming an increasingly important issue in many data-mining applications. This has triggered the development of many privacy-preserving data-mining techniques. A large fraction of them use randomized data-distortion techniques to mask the data for preserving the privacy of sensitive data. This methodology attempts to hide the sensitive data by randomly modifying the data values often using additive noise. This paper questions the utility of the random-value distortion technique in privacy preservation. The paper first notes that random matrices have predictable structures in the spectral domain and then it develops a random matrix-based spectral-filtering technique to retrieve original data from the dataset distorted by adding random values. The proposed method works by comparing the spectrum generated from the observed data with that of random matrices. This paper presents the theoretical foundation and extensive experimental results to demonstrate that, in many cases, random-data distortion preserves very little data privacy. The analytical framework presented in this paper also points out several possible avenues for the development of new privacy-preserving data-mining techniques. Examples include algorithms that explicitly guard against privacy breaches through linear transformations, exploiting multiplicative and colored noise for preserving privacy in data mining applications.     

Numerical prediction of the performance,combustion and emission characteristics of a CI engine using different biodiesels

An attempt has been made to investigate numerically the energetic, combustion and environmental performances of a single-cylinder naturally aspirated direct injection diesel engine using the commercial software, Diesel-RK. Diesel and five different biodiesels, namely jatropha biodiesel, soybean biodiesel, palm stearin biodiesel, karanja biodiesel and rapeseed biodiesel, are used separately as fuels in this study. Experiments have also been conducted with diesel and palm stearin biodiesel to validate the predicted results. The experimental and the numerical results match both qualitatively and quantitatively with slight deviations. The analysis of the numerical results shows that the engine performance deteriorates with the use of different biodiesels as fuels. Brake thermal efficiency decreases by 3% (maximum) in case of palm stearin biodiesel. On the other hand, brake specific fuel consumption and brake specific energy consumption increase and the maximum values are found to be 25.8 and 3.6%, respectively. Among the biodiesels, jatropha biodiesel showed the best performance and palm stearin biodiesel showed the worst. When the combustion characteristics were compared, it was noted that both the ignition delay period and the heat release rate decrease to some extent for different biodiesels compared to diesel. The use of biodiesel gives a cleaner exhaust compared to that of diesel, and jatropha biodiesel gives the cleanest exhaust in terms of particulate matter and smoke emissions. However, the formation of nitrogen oxides increases with the use of biodiesels and the maximum increase was noted with rapeseed biodiesel.     

Finite element analysis of laminated composite plates using zeroth-order shear deformation theory

In this paper a generalized finite element model is developed for static and dynamic analyses of laminated composite plates using zeroth-order shear deformation theory (ZSDT). The theory ensures the parabolic distribution of transverse shear stresses across the plate thickness. A four-noded plate element is considered in this model and the generalized nodal variables are expressed using Lagrangian linear interpolation functions and Hermitian cubic interpolation functions. The solutions of the finite element model have been compared with the existing solutions for symmetric and antisymmetric laminated composite plates. The comparison confirms that the ZSDT can be efficiently used for finite element analysis of both thin and thick plates with high accuracy.     

Molybdenum Oxides – From Fundamentals to Functionality

The properties and applications of molybdenum oxides are reviewed in depth. Molybdenum is found in various oxide stoichiometries, which have been employed for different high‐value research and commercial applications. The great chemical and physical characteristics of molybdenum oxides make them versatile and highly tunable for incorporation in optical, electronic, catalytic, bio, and energy systems. Variations in the oxidation states allow manipulation of the crystal structure, morphology, oxygen vacancies, and dopants, to control and engineer electronic states. Despite this overwhelming functionality and potential, a definitive resource on molybdenum oxide is still unavailable. The aim here is to provide such a resource, while presenting an insightful outlook into future prospective applications for molybdenum oxides.     

An experimental investigation on the performance,combustion and emission characteristics of a variable compression ratio diesel engine using diesel and palm stearin methyl ester

An attempt has been made to use biodiesel prepared from non-edible portion of palm oil as fuel of a conventional mono-cylinder compression ignition engine. The present experimental investigation takes into account the combined effect of using blends of diesel–palm stearin biodiesel as fuels and the compression ratio on different performance, combustion and emission characteristics of the said engine. The experiments have been carried out on a single-cylinder, direct injection diesel engine at varying compression ratio of 16:1–18:1 in four steps. It is observed that the brake thermal efficiency reduces by 7.9% when neat biodiesel is used instead of diesel. But, it increases with the increase in compression ratio for all the blends. Brake specific fuel consumption and exhaust gas temperature increase with the addition of biodiesel to diesel and also with the increase in compression ratio. Heat release rate decreases with biodiesel, and it is minimum at the rated compression ratio of 17.5:1 for all the fuels considered here. On the other hand, ignition delay is found to be more with neat diesel, and it increases with the decrease in compression ratio. Significant reductions in emissions of carbon monoxide (CO), hydrocarbon (HC) and smoke are observed with biodiesel, while the emissions of oxides of nitrogen (NO_x) and carbon dioxide (CO₂) increase. The decrease in compression ratio increases the emissions of CO, HC and smoke, but the emissions of NO_x and CO₂ decrease with the decrease in compression ratio.     

Ultrathin Hierarchical Porous Carbon Nanosheets for High‐Performance Supercapacitors and Redox Electrolyte Energy Storage

The design of advanced high‐energy‐density supercapacitors requires the design of unique materials that combine hierarchical nanoporous structures with high surface area to facilitate ion transport and excellent electrolyte permeability. Here, shape‐controlled 2D nanoporous carbon sheets (NPSs) with graphitic wall structure through the pyrolysis of metal–organic frameworks (MOFs) are developed. As a proof‐of‐concept application, the obtained NPSs are used as the electrode material for a supercapacitor. The carbon‐sheet‐based symmetric cell shows an ultrahigh Brunauer–Emmett–Teller (BET)‐area‐normalized capacitance of 21.4 µF cm^?2 (233 F g^?1), exceeding other carbon‐based supercapacitors. The addition of potassium iodide as redox‐active species in a sulfuric acid (supporting electrolyte) leads to the ground‐breaking enhancement in the energy density up to 90 Wh kg^?1, which is higher than commercial aqueous rechargeable batteries, maintaining its superior power density. Thus, the new material provides a double profits strategy such as battery‐level energy and capacitor‐level power density.     

Repositing honey incorporated electrospun nanofiber membranes to provide anti-oxidant,anti-bacterial and anti-inflammatory microenvironment for wound regeneration

Topical application of honey for tissue regeneration, has recently regained attention in clinical practice with controlled studies affirming its efficacy and indicating its role in regeneration over repair. Parallely, to overcome difficulties of applying raw honey, several product development studies like nanofibrous matrices have been reported. However, one approach concentrated on achieving highest possible honey loading in the nanofiber membranes while other studies have found that only specific honey dilutions result in differential cellular responses on wound healing and re-epithelization. From these results, it can be suggested that high honey loading provides optimum external microenvironment, low-loaded membranes could provide a more conducive internal microenvironment for tissue regeneration. With this hypothesis, this paper sought to evaluate ability of low-honey loaded nanofibers to modulate the anti-oxidant, anti-biofilm and anti-inflammatory properties which are important to be maintained in wound micro-environment. A loading-dependent reduction of biofilm formation and anti-oxidant activity was noted in different concentration ranges investigated. After scratch assay, a certain honey loading (0.5%) afforded the maximum re-epithelization. Since there is lack of methods to determine anti-inflammatory properties of nanofiber membranes during epithelial healing process, we performed anti-inflammatory assessment of nano-fibers by evaluating the expressions of pro-inflammatory markers-Cycloxygenase-2 (COX-2) and Interleukin-6 (IL-6) and to confirm the optimized concentration. Considering the role of COX-2 and IL-6, the novel methodology used in this study can also be developed as an assay for anti-inflammatory matrices for wound healing.

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An online‐offline prognosis model for fatigue life prediction under biaxial cyclic loading with overloads

This paper presents a robust online‐offline model for the prediction of crack propagation under complex in‐phase biaxial fatigue loading in the presence of overloads of different magnitudes. The online prognosis model comprises a combination of finite element analysis and data‐driven regression to predict the crack propagation under constant loading, while the offline model is trained using experimental data to inform the post‐overload crack growth retardation behavior to the online model. The developed methodology is validated by conducting biaxial fatigue experiments using aluminum AA7075‐T651 alloy cruciform specimens. A close correlation is observed between the experimental results and model predictions. The results show that the model successfully predicts the crack retardation behavior under the influence of overloads with different magnitudes occurring at different stages of fatigue crack growth. Error analysis is conducted to investigate the sensitivities of the number of training points and crack increments to the prediction accuracy. In addition, the error propagation with respect to the crack length is studied, which provides constructive suggestions for further model improvement.     

Development of Multi-chroic MKIDs for Next-Generation CMB Polarization Studies

We report on the status of an ongoing effort to develop arrays of horn-coupled, polarization-sensitive microwave kinetic inductance detectors (MKIDs) that are each sensitive to two spectral bands between 125 and 280 GHz. These multi-chroic MKID arrays are tailored for next-generation, large-detector-count experiments that are being designed to simultaneously characterize the polarization properties of both the cosmic microwave background and Galactic dust emission. We present our device design and describe laboratory-based measurement results from two 23-element prototype arrays. From dark measurements of our first engineering array, we demonstrated a multiplexing factor of 92, showed the resonators respond to bath temperature changes as expected, and found that the fabrication yield was 100%. From our first optically loaded array, we found the MKIDs respond to millimeter-wave pulses; additional optical characterization measurements are ongoing. We end by discussing our plans for scaling up this technology to kilo-pixel arrays over the next 2 years.