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The aim of this paper is to introduce a novel frequency reuse concept especially for macro cellular networks to substantially increase the mobile network capacity, and simultaneously to avoid the implementation of low efficient small cells. Single path multiple access (SPMA) utilizes the characteristics of independent propagation paths for particular geographical location in the coverage area of mobile network. The proposed concept is based on the assumption that new approach will be adopted by the antenna manufacturers for producing advanced antennas by utilizing materials like metamaterials including carbon based nanotechnology, and graphene. In SPMA concept, communication between base station and mobile station happens through only single independent propagation path, and frequency resources can be reused in 5 m \(\times \) 5 m areas or even more often in 1 m \(\times \) 1 m areas, but limited by a base station/mobile station antenna requirement. Thus, the capacity of the network will be increased dramatically, and it can be managed in centralized manner at certain macro site locations. In already deployed cellular networks, these macro sites are mostly easily available, and that would help to implement SPMA to enhance the network capacity. Simulation results provided in this paper show the applicability of SPMA technique, by limiting the radiation of signal as single path propagation between base station and mobile station. 相似文献
54.
H. D. Chalak Anupam Chakrabarti Abdul Hamid Sheikh Mohd. Ashraf Iqbal 《先进材料力学与结构力学》2015,22(11):897-907
C0 finite element model based on higher order zig-zag plate theory is used to study the stability analysis of laminated sandwich plates. The in-plane displacement field is obtained by superposing a global cubically varying displacement field on a zig-zag linearly varying displacement field with different slope in each layer. The transverse displacement assumes to have a quadratic variation within the core and constant in the faces. The conditions regarding transverse shear stress at layer interfaces and top and bottom are satisfied. Numerical examples covering different features of laminated sandwich plates are presented to illustrate the accuracy of the model. 相似文献
55.
We propose a joint optimization network management framework for quality‐of‐service (QoS) routing with resource allocation. Our joint optimization framework provides a convenient way of maximizing the reliability or minimizing the jitter delay of paths. Data traffic is sensitive to droppage at buffers, while it can tolerate jitter delay. On the other hand, multimedia traffic can tolerate loss but it is very sensitive to jitter delay. Depending on the type of data, our scheme provides a convenient way of selecting the parameters which result in either reliability maximization or jitter minimization. We solve the optimization problem for a GPS network and provide the optimal solutions. We find the values of control parameters which control the type of optimization performed. We use our analytical results in a multi‐objective QoS routing algorithm. Finally, we provide insights into our optimization framework using simulations. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
56.
Rahimah MuhamadM.S. Mohamed Ali Deric OehlersA. Hamid Sheikh 《Engineering Structures》2011,33(4):1098-1106
An accurate evaluation of the moment-rotation relationship of reinforced concrete members at both serviceability and ultimate limit states is a very important aspect as rotation has a significant contribution to the deflection of the member and also has a direct impact on the magnified moment, the ability to absorb energy and the redistribution of moments. The rotation in the un-cracked or homogenous parts of a reinforced concrete member can be determined by integrating the curvature using standard procedures. However, in the cracked or non-homogenous regions, rotations are found to have sudden or discrete changes at each crack between their crack faces. This can be quantified by the crack opening produced by the slip Δ between the reinforcement and the concrete at the crack face induced by the force in the reinforcing bar P. In this paper, closed form solutions are derived for the P-Δ relationships which are applicable to any type and shape of reinforcement. It is then shown how these closed form solutions can be conveniently used to derive the moment-rotation relationship at a crack. 相似文献
57.
C Freitag AB Svendsen N Feldthus K L?ssl SP Sheikh 《Canadian Metallurgical Quarterly》1995,64(2):643-650
This study of location information involved in information persistence used the partial-report paradigm. Six subjects were asked on 144 trials to recall positions of dots presented in a display. The subjects were instructed to maintain only information on location (but not on identity information) of the presented dots until a partial-report cue was introduced. The effects of display duration (50, 200, and 350 msec.) and cue delay (interval between the display offset and the onset of the partial-report cue: 50, 250, and 500 msec.) were examined. Analysis showed effect of cue delay on partial-report performance decreased as the duration of display increased so performance was negatively affected by the cue delay only when the subject was exposed to the presented dots for 50 msec. Contrarily, partial-report performance did not decline much for a 200-msec. duration and showed little variation in a 350-msec. duration, even though the cue delay increased. Consequently, the decay of the information on location mediating partial-report performance about dots varies with duration of display. 相似文献
58.
Falconer D. Sheikh A. Eleftheriou E. Tobis M. 《Communications, IEEE Transactions on》1985,33(5):484-486
Data communication at rates near or above 2 kbits/s on 3 kHz-baadwidth HF radio channels is subject to impairment from severe linear dispersion, rapid channel time variation, and severe fading. In this investigation, recorded 2.4 kbit/s QPSK signals received from HF channels were processed to extract a time-varying estimate of the channel impulse response. From the estimated channel impulse responses, performance-related parameters were computed for ideal matched filter reception, maximum-likelihood sequence-estimation (MLSE), and decision feedback equalization (DFE). The results indicated that the simpler DFE receiver suffered only a small theoretical performance degradation relative to the more complex MLSE receiver. Other HF channel impulse response statistics were also obtained to shed light on equalization and filter adaptation techniques. 相似文献
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Bahman Sheikh Philip N. Storrs Thomas J. Jones Joyce S. Hsiao William R. Kirkpatrick 《Desalination》1981
The Monterey Wastewater Reclamation Study for Agriculture (MWRSA) has Completed its first year of a five-year pilot effort to investigate and to demonstrate feasibility of food crop irrigation with reclaimed municipal effluent. The project comprises a 96-plot field trial for statistical comparison of three water treatments: an eight-hectare commercial scale farm for demonstration of water reclamation for growing lettuce, broccoli, cauliflower, celery, and artichokes; an aerosol study, a virus assay, market studies, and other ancillary investigations. First year results preliminarily indicate that the main hypothesis of the study will prove to be true, i.e. “raw-eaten food crops irrigated with properly treated municipal wastewater effluent are safe for human consumption”. 相似文献