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61.
Murat  Ritesh  Shivkumar 《Ad hoc Networks》2006,4(1):125-137
Routing in ad hoc networks is a complicated task because of many reasons. The nodes are low-memory, low-powered, and they cannot maintain routing tables large enough for well-known routing protocols. Because of that, greedy forwarding at intermediate nodes is desirable in ad hoc networks. Also, for traffic engineering, multi-path capabilities are important. So, it is desirable to define routes at the source like in source based routing (SBR) while performing greedy forwarding at intermediate nodes.We investigate trajectory-based routing (TBR) which was proposed as a middle-ground between SBR and greedy forwarding techniques. In TBR, source encodes trajectory to be traversed and embeds it into each packet. Upon the arrival of each packet, intermediate nodes decode the trajectory and employ greedy forwarding techniques such that the packet follows its trajectory as much as possible.In this paper, we address various issues regarding implementation of TBR. We also provide techniques to efficiently forward packets along a trajectory defined as a parametric curve. We use the well-known Bezier parametric curve for encoding trajectories into packets at source. Based on this trajectory encoding, we develop and evaluate various greedy forwarding algorithms  相似文献   
62.
Multimedia Tools and Applications - An electromagnetic field radiations (EMF) emanating from the cell phones affect the brain and other organs in living organisms. Therefore, the objective of the...  相似文献   
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This paper presents a comparison between particulate filled (SiC particles) and unfilled glass polyester composites on the basis of their mechanical and thermo-mechanical properties. The results show that particulate filled composites have a decreasing trend in mechanical properties when compared to the unfilled glass polyester composites. In particulate filled composites, the tensile and flexural strength of the composites decrease with the addition of 10 wt.-% SiC particles but increase with 20 wt.-% SiC particles. In the case of the unfilled glass polyester composite, the tensile and flexural strength of the composites increase with an increase in the fiber loading. However, higher values of tensile strength and flexural strength of particulate filled glass polyester were found than that of the unfilled glass polyester composite. In the case of thermo-mechanical and thermal properties, the particulate filled composites show better dynamical and thermal properties when compared to the unfilled glass polyester composites. The mechanical and thermal properties (i.e. thermal conductivity) are also calculated using FE modeling (ANSYS software) and the results from this simulation shows good agreement with the experimental results.  相似文献   
65.
Commonly used security mechanisms such as cryptography and steganography suffer from weaknesses when used in a standalone manner. Extra efforts in the form of additional permutations/diffusions etc. result in higher ciphering/deciphering time complexity. Thus, there is a requirement for a security mechanism(s) which can provide adequate security without putting a considerable burden on ciphering/deciphering time complexity. This paper is an effort in this direction. The paper proposes a hybrid mechanism that employs chaotic based encryption scheme to encrypt data and an improved Bit-Plane Complexity Segmentation Steganography algorithm to embed the data. The proposed mechanism uses two new complexity measures to differentiate between noisy regions and simple ones appropriately. The scheme was implemented in MATLAB, and the simulation results show that the proposed mechanism has high embedding capacity, high security with a moderate decrease in PSNR value and is computationally fast.  相似文献   
66.
In the present paper, a parameter-uniform numerical method is constructed and analysed for solving one-dimensional singularly perturbed parabolic problems with two small parameters. The solution of this class of problems may exhibit exponential (or parabolic) boundary layers at both the left and right part of the lateral surface of the domain. A decomposition of the solution in its regular and singular parts has been used for the asymptotic analysis of the spatial derivatives. To approximate the solution, we consider the implicit Euler method for time stepping on a uniform mesh and a special hybrid monotone difference operator for spatial discretization on a specially designed piecewise uniform Shishkin mesh. The resulting scheme is shown to be first-order convergent in temporal direction and almost second-order convergent in spatial direction. We then improve the order of convergence in time by means of the Richardson extrapolation technique used in temporal variable only. The resulting scheme is proved to be uniformly convergent of order two in both the spatial and temporal variables. Numerical experiments support the theoretically proved higher order of convergence and show that the present scheme gives better accuracy and convergence compared of other existing methods in the literature.  相似文献   
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Worldwide obesity has reached a pandemic proportion. World Health Organization (WHO) estimates that by 2020, two thirds of the global disease burden will be attributable to obesity and obesity associated complications. Existing anti-obesity drugs, affecting one of the fundamental processes of the weight regulation in human body, have displayed serious side effects which outweigh their beneficial effects. Clinical and non-clinical researchers in this area are now facing a challenge to search for non-pharmacological alternatives for the prevention of obesity. Dietary interventions and life style changes with enhanced physical activity are two such options. Considering the importance of dietary interventions, the present review highlights the role, significance and potential of functional food ingredients for the management of obesity and associated co-morbidities.  相似文献   
69.
In the proposed work the model has been formulated for discretized doped HEMT, where the conventional uniformly doped, pulsed doped and delta doped structure are the special cases. An expression for sheet carrier density has been formulated considering the effect of doping-thickness product and has been extended to calculate drain current, transconductance, capacitance and cut-off frequency of the device. The model also takes into account the non-linear relationship between sheet carrier density and quasi Fermi energy level to validate it from subthreshold region to high conduction region. The results so obtained have been compared with pulsed doped structure to validate the model. The analysis concentrates on the distance of doping from the heterojunction and gate electrode. Different design criteria have been given to dope the carriers (amount and distance) in different regions to optimize the performance for higher sheet carrier density/parallel conduction voltage/effective parallel conduction voltage (Vc−Voff) to increase the transconductance, cut-off frequency and reliability of the device.  相似文献   
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