Voltage difference engineering in SOI MOSFETs: A novel side gate device with improved electrical performance

We studied the impact of voltage difference engineering in a silicon-on-insulator metal oxide semiconductor field-effect transistor (SOI-MOSFET) and compared the performance to that of a conventional SOI-MOSFET (C-SOI). Our structure, called a SIG-SOI MOSFET, includes main and side gates with an optimum voltage difference between them. The voltage difference leads to an inverted channel as an electrical drain extension under the side gate. This channel creates a stepped potential distribution along the channel that it cannot be seen in the C-SOI MOSFETs. The voltage difference controls the channel properly and two-dimensional two-carrier device simulations revealed lower threshold voltage variations, larger breakdown voltage, higher voltage gain, lower hot carrier effects, improved drain-induced barrier lowering, lower drain conductance, higher unilateral power gain, and lower leakage current compared to a C-SOI device. Thus, our proposed structure has higher performance than a typical C-SOI structure.     

An improved cluster formation process in wireless sensor network to decrease energy consumption

Wireless sensor network has special features and many applications, which have attracted attention of many scientists. High energy consumption of these networks, as a drawback, can be reduced by a hierarchical routing algorithm. The proposed algorithm is based on the Low Energy Adaptive Clustering Hierarchy (LEACH) and Quadrant Cluster based LEACH (Q-LEACH) protocols. To reduce energy consumption and provide a more appropriate coverage, the network was divided into several regions and clusters were formed within each region. In selecting the cluster head (CH) in each round, the amount of residual energy and the distance from the center of each node were calculated by the base station (including the location and residual energy of each node) for all living nodes in each region. In this regard, the node with the largest value had the highest priority to be selected as the CH in each network region. The base station calculates the CH due to the lack of energy constraints and is also responsible for informing it throughout the network, which reduces the load consumption and tasks of nodes in the network. The information transfer steps in this protocol are similar to the LEACH protocol stages. To better evaluate the results, the proposed method was implemented with LEACH LEACH-SWDN, and Q-LEACH protocols using MATLAB software. The results showed better performance of the proposed method in network lifetime, first node death time, and the last node death time.

     

A Convex Programming for Range Assignment to Optimize Lifetime in Network-Coding-Based-Wireless-Sensor Networks

Wireless sensor networks (WSNs) are known to be highly energy-constrained and  consequently lifetime is a critical metric in their design and implementation. Range assignment by adjusting the transmission powers of nodes create a energy-efficient topology for such networks while preserving other network issues, however, it may effect on the performance of other techniques such as network coding. This paper addresses the problem of lifetime optimization for WSNs where the network employs both range assignment and network-coding-based multicast. We formulate the problem and then reformulated it as convex optimization that offer a numerous theoretical or conceptual advantages. The proposed programming leads to efficient or distributed algorithms for solving the problem. Simulation results show that the proposed optimized mechanism decreases end-to-end delay and improve lifetime as compared by other conventional ones.     

An Anti-Gray Hole Attack Scheme in Mobile Ad Hoc Network

International Journal of Wireless Information Networks - Dynamic variation of network topology in mobile ad hoc networks (MANET) forces network nodes to work together and rely on each other for...     

Grid computing: a STOPE view

Grid computing is emerging as the foundation upon which virtual organizations can be built. Such organizations are becoming of increasing importance for tackling various projects, both in academic and in business fields. This paper is concerned with presenting an integrated view of the grid to readers interested in understanding it, or perhaps in developing it further or making use of it in the future. The target view is based on the STOPE (strategy/technology/organization/people/environment) framework that has previously been used to integrate the issues of various information technology problems over its well‐defined domains. For strategy, the view considers the reasons associated with the need for the grid, including grid services and grid benefits. For technology, the technical components of the grid and their functions are taken into account. For organization, the organizations concerned with the development, technology production, service provisioning and use of the grid are considered. For people, those associated with the grid in the related organizations are taken into account. For the environment, rules, practices and support associated with the grid are discussed. Finally, the paper emphasizes questions that need to be answered in order to contribute to the future development of the grid. Copyright © 2006 John Wiley & Sons, Ltd.     

Underlay Device to Device Communication with Imperfect Interference Channel Knowledge

The objective of any night vision system is to enable a person to see in the dark. A low-contrast image puts a contrast constraint on the human observer visibility at night. This is the basic reason for the large number of accidents at night. This research presents two proposed approaches to enhance the visibility of the infrared (IR) night vision images through an efficient histogram processing. The first approach is based on contrast limited adaptive histogram equalization. The second proposed approach depends on histogram matching. The histogram matching uses a reference visual image for converting night vision images into good quality images. The obtained results are evaluated with quality metrics such as entropy, average gradient, contrast improvement factor and sobel edge magnitude.     

The Einstein relation for degenerate semiconductors with nonuniformband structures

Modification of the Einstein equation for semiconductors with nonparabolic energy bands and doped nonuniformly with impurity atoms is suggested. The suggestion is based on a new approximation of the Fermi-Dirac integral of order 1/2, namely, F_1/2(η_n), where η_n is the reduced Fermi level for electrons. The relation reduces to that for semiconductors with parabolic energy bands and doped uniformly with impurity atoms under appropriate boundary conditions. A comparison of the calculated and exact results for F_1/2(η) is found to be very encouraging     

A New Method Modifying Single Miller Feedforward Frequency Compensation to Drive Large Capacitive Loads: Putting an Attenuator in the Path

A new method to compensate three-stage amplifier to drive large capacitive loads is proposed in this paper. Gain Bandwidth Product is increased due to use an attenuator in the path of miller compensation capacitor. Analysis demonstrates that the gain bandwidth product will be improved significantly without using large compensation capacitor. Using a feedforward path is deployed to control a left half plane zero which is able to cancel out first non-dominant pole. A three stage amplifier is simulated in a 0.18 μm CMOS technology. The purpose of the design is to compensate three-stage amplifier loading 1000 pF capacitive load. The simulated amplifier with a 1000 pF capacitive load is performed in 3.3 MHz gain bandwidth product, and phase margin of 50. The compensation capacitor is reduced extremely compared to conventional nested miller compensation methods. Since transconductance of each stage is not distinct, and it is close to one another; as a result, this method is suitable low power design methodology.     

TD-LTE:抢占无线全新商机带动全球发展势态

LTE是目前大部分电信运营商首选的下一代移动通信技术,已有100多家运营商承诺将于2010年开始部署LTE.不过,在非成对频段部署LTE的商机却常被忽略.