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11.
Murad Khan Awais Ahmad Shehzad Khalid Syed Hassan Ahmed Sohail Jabbar Jamil Ahmad 《Multimedia Tools and Applications》2017,76(23):24649-24674
Vertical handover gain significant importance due to the enhancements in mobility models by the Fourth Generation (4G) technologies. However, these enhancements are limited to specific scenarios and hence do not provide support for generic mobility. Similarly, various schemes are proposed based on these mobility models but most of them are suffered from the high packet loss, frequent handovers, too early and late handovers, inappropriate network selection, etc. To address these challenges, a generic vertical handover management scheme for heterogeneous wireless networks is proposed in this article. The proposed scheme works in three phases. In the first phase, a handover triggering approach is designed to identify the appropriate place for initiating handover based on the estimated coverage area of a WLAN access point or cellular base station. In the second phase, fuzzy rule based system is designed to eliminate the inappropriate networks before deciding an optimal network for handover. In the third phase, a network selection scheme is developed based on the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) decision mechanism. Various parameters such as delay, jitter, Bit Error Rate (BER), packet loss, communication cost, response time, and network load are considered for selecting an optimal network. The proposed scheme is tested in a mobility scenario with different speeds of a mobile node ranging from very low to very high. The simulation results are compared with the existing decision models used for network selection and handover triggering approaches. The proposed scheme outperforms these schemes in terms of energy consumption, handover delay and time, packet loss, good put, etc. 相似文献
12.
A model of a decision support system based on case-based reasoning for third-party logistics evaluation 总被引:1,自引:0,他引:1
The social demands for third‐party logistics (3PL) are further developing the model of supply chain management. The analysis of an effective approach for 3PL service supplier evaluation is given in terms of its direct relation to the operational efficiency and benefit of the service‐demanding enterprise as well as its supply chain management. An analysis of the traditional academic theoretical results and practical methods for 3PL supplier selection indicates the deficiencies of this approach. In this paper, a case‐based reasoning model framework is postulated for a 3PL evaluation and selection system. This work further expands upon the theoretical basis of this system and its reasoning process by discussing the advantages and practical value of this framework. 相似文献
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Sarwar Sohail Qayyum Zia Ul García-Castro Raúl Safyan Muhammad Munir Rana Faisal 《Multimedia Tools and Applications》2019,78(24):34745-34771
Multimedia Tools and Applications - Enhancing the degree of learner productivity, one of the major challenges in E-Learning systems, may be catered through effective personalization, adaptivity and... 相似文献
16.
Iftikhar Ahmad M. Mohib Ur Rehman Masroor Khan Ahmad Abbas Sarmad Ishfaq Sohail Malik 《国际能源研究杂志》2019,43(10):5384-5391
Battery is the sole power source for Internet of thing (IoT) sensors. Due to limited shelf life, the batteries are required to be replaced intermittently. This periodic replacement of batteries is inflated in terms of both logistics and time. This article illustrates conceptual design, development, and characterization of a flow‐based electromagnetic‐type energy harvester (F‐EH) using microplanar coil for IoT sensors application. The F‐EH converts hydro energy into useful electrical energy utilizing electromagnetic transduction mechanism. The microfabrication and macrofabrication techniques adopted to manufacture harvester's components are presented. The F‐EH has been successfully characterized by laboratory scale experimental flow test loop commissioned for this work. Experimentation with associated uncertainty analysis prevails that at a matching impedance, the F‐EH can generate a 686 μW of maximum power at an operating flow rate of 12 L/min with an uncertainty of 8.1%. 相似文献
17.
In this article, a ternary WO3/g‐C3N4@ BiVO4 composites were prepared using eco‐friendly hydrothermal method to produce efficient hydrogen energy through water in the presence of sacrificial agents. The prepared samples were characterized by scanning electron microscopy (SEM), scanning transmission electron microscopy (STEM), transmission electron microscopy (TEM), X‐ray diffraction (XRD), ultraviolet‐visible (UV‐vis), Brunauer‐Emmett‐Teller (BET) surface area, and photoluminescence spectroscopy (PL) emission spectroscopy. The experimental study envisages the formation of 2‐D nanostructures and observed that such kinds of nanostructures could provide more active sites for photocatalytic reduction of water and their inherent reactive‐species mechanism. The results showed the excellent photocatalytic performance (432 μmol h?1 g?1) for 1.5% BiVO4 nanoparticles in WO3/g‐C3N4 composite when compared with pure WO3 and BiVO4. The optical properties and photocatalytic activity measurement confirmed that BiVO4 nanoparticles in WO3/g‐C3N4 photocatalyst inhibited the recombination of photogenerated electron and holes and enhanced the reduction reactions for H2 production. The enhanced photocatalytic efficiency of the composite nanostructures may be attributed to wide absorption region of visible light, large surface area, and efficient separation of electrons/holes pairs owing to synergistic effects between BiVO4 and WO3/g‐C3N4. The prepared samples would be a precise optimal photocatalyst to increase their suppliers for worldwide applications especially in energy harvesting. 相似文献
18.
Abstract Although it is well known that light carries momentum and exerts a pressure on objects, a conservation of momentum principle is apparently rarely used in optics. In nonlinear optics light waves interact and may exchange both energy and momentum. We demonstrate that a conservation of momentum principle holds in these cases and in fact its use is widespread but generally unrecognized in the standard mathematical methods. In both the cases of linear basis waves interacting nonlinearly, e.g. coupled-wave theory and frequency mixing, and fully nonlinear waves, we demonstrate that a governing Hamiltonian is related to momentum. Action principles are used to discuss the generality of these results. 相似文献
19.
Be-doped TlBa2(Ca2−yBey)Cu3O10−δ (y=0, 0.25, 0.5, 0.75, and 1.0) superconductor bulk samples were synthesized by solid state reaction and characterized by X-ray diffraction (XRD), dc-resistivity {ρ (Ω cm)}, and Fourier Transform Infrared (FTIR) absorption spectroscopy. Fluctuations induced conductivity (FIC) analysis is carried out on temperature dependent dc-resistivity data of as-prepared and oxygen post-annealed TlBa2(Ca2−yBey)Cu3O10−δ superconductor samples by using Aslamazov–Larkin (AL) and Lawrence–Doniach (LD) models for excess conductivity. Different microscopic parameters such as zero temperature coherence length along c-axis {ξc(0)}, inter-layer coupling (J), inter-grain coupling (α), critical exponent (λD) and dimensionality of fluctuations are calculated for understanding the role of Be-doping on superconducting properties of TlBa2(Ca2−yBey)Cu3O10−δ samples. The cross-over temperature (To) is shifted towards higher temperature values with the increase of Be contents in TlBa2(Ca2−yBey)Cu3O10−δ samples. The increase in ξc(0) and J after Be-doping at Ca sites shows the improvement of inter-plane coupling in TlBa2(Ca2−yBey)Cu3O10−δ samples. The increase in zero resistivity critical temperature {Tc(R=0) (K)} up to y=0.5 and then decrease for y=0.75, 1.00 fixed the Be-doping level for optimum increase of superconducting properties of TlBa2(Ca2−yBey)Cu3O10−δ samples. The appreciable changes in all the microscopic parameters extracted from the FIC analysis and the increase in relative intensity of almost all the oxygen phonon modes indicate the oxygen diffusion in the unit cell after oxygen post-annealing the samples. The oxygen diffusion can take place at both inter-granular and intra-granular sites, which increase the superconducting volume fraction by improving the grains size, inter-grain connectivity and carrier density. 相似文献
20.
Structural,viscoelastic, and vulcanization study of sponge ethylene–propylene–diene monomer composites with various carbon black loadings 下载免费PDF全文
In this article, we report the effect of various carbon nanoparticle concentrations on the structural, curing, tan δ, viscosity variation during vulcanization, thermal, and mechanical characteristics of ethylene–propylene–diene monomer polymer sponge composites. The purpose of this study was to develop high‐strength, foamy‐structure polymer composites with an optimum filler to matrix ratio for advanced engineering applications. We observed that the structural, vulcanization, viscoelastic, and mechanical properties of the fabricated composites were efficiently influenced with the progressive addition of carbon content in the rubber matrix. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39423. 相似文献