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Abstract: Heterojunction silicon wafer solar cells, using a microcrystalline silicon (μc-Si:H) thin-film emitter and a very thin intrinsic amorphous silicon (a-Si:H) passivation layer between the crystalline silicon wafer and the emitter layer, have been reported to exhibit stable performance and high efficiency. Desired properties for the emitter layer include wide bandgap, low surface and interface recombination, and good doping efficiency. In this study, we report on the thin-film properties of p-doped μc-Si:H emitter layers deposited using RF (13.56MHz) PECVD, at different SiH4/H2 gas flow ratios, pressures, and temperatures at the same RF power. Trends relating deposition conditions to relevant film characteristics such as thickness, crystalline fraction and conductivity are discussed. Finally, device relevant symmetrical p+/i/c-Si/i/p+ heterojunction lifetime test structures are investigated, using the optimised parameters for p-doped μc-Si:H layers (discussed in this paper) and for intrinsic a-Si:H layers (discussed in a companion paper ). These exhibit promising effective lifetimes of up to 2.4ms at an injection level of 1015cm-3. [Copyright &y& Elsevier]

Abstract: Digital Fountain code is a forward error correction code developed in recent years. The code does not need to know the channel information, and can be decoded with high probability. LT code is the first practical digital fountain code, it has fully inherited the advantages of digital fountain code. This paper introduces the concept and the classifications of Digital Fountain code, especially about the encoding and decoding process, the degree distribution and the application environment of LT code; the parameters of the degree distribution of LT code are discussed through the simulation, the optimization parameters of LT code are given and the importance of each parameter is analyzed; the paper has obtained the specific value of the decoding failure probability of Digital Fountain code; the effects of the amount of data received on LT code as well as the best amount of data have been studied; Finally, a model about how the Digital Fountain code can be used in the real application is given, make it gradually been used in the practical application. [Copyright &y& Elsevier]

Abstract: Shape optimization design has been paid more attention in many industrial fields, but the application of automatic method for naval ship hydrodynamic design has not reached the same level of maturity. Even so, it introduces numerical tools, combines with CFD and optimization methods, which contribute to ship design, can improve the ship performance, and reduce the cost of development and building. This paper proposes to apply the CFD technology to automatic optimization of hull form of naval ship, and builds hull form optimization frame based on CFD, to execute form optimization for sonar position of surface combatant –David Taylor model basin (DTMB) 5415 ship model. The result illustrates that the research of the paper has great value in engineering application. [Copyright &y& Elsevier]

Abstract: Impact of users on thermal behaviour of a building and a building''s impact on the use of different spaces are two aspects that are subject of post occupancy evaluation of the present paper. The building was designed according to passive concepts, including Insulated envelope and internal thermal mass; also computer simulations were used to optimize thermal performance of different components of the design. The evaluation was done by using quantitative method to document climate and interior lighting. A qualitative method was also used for analysis of building use and perception of indoor climate by users. High windows were placed in the hall and lobby for night flush to cool the building during summer. However, the difficulty of opening them had led that night ventilation was never practiced. In winter, less window''s areas would be sufficient to satisfy the thermal comfort during the day while ensuring a sufficient level of natural lighting. Daylight level measured in the morning shows that the level of illumination is acceptable; however it remains below the required minimum during the afternoon during fall, winter and spring. Small to medium windows, (4-10% of floor area) on west orientation could improve the daylight during the afternoon. Also, a late closing of the youth club would be desirable for the spring, summer and fall when days are long. The results of the interviews describe a high level of satisfaction from users with regard to indoor climate. Bioclimatic design has a positive impact on the use of the youth. [Copyright &y& Elsevier]

Abstract: In this paper, the effect of material composition on the overheating protection performance of thermotropic systems with fixed domains (TSFD) is studied. Several thermotropic layers were formulated by variation of both, matrix material and thermotropic additive. Refractometry was applied in order to obtain refractive index data as a function of temperature of all material constituents and to screen wether material combinations are promising to formulate or not. Investigations concerning optical properties, switching temperature and switching process were carried out applying UV/Vis/NIR spectrometry. Morphological analysis was conducted with a Scanning Electron Microscope (SEM). Several TSFD showed reasonable light-shielding efficiency. Nevertheless further optimization of scattering domain size and shape is necessary to improve the light shielding performance. [Copyright &y& Elsevier]

Abstract: Reactive power optimization plays a significant role in the operation of wind farm grid intern connection to maintaining voltage stability and system reliability. Genetic algorithm (GA) is an efficient method which can be applied in reactive power optimization to reduce power loss and improve power quality. However, traditional GA has some defects, such as slow convergence and prematurity. For improvement, the paper modified decoding method, genetic operators, crossover and mutation probability, iteration stopping criterion based on the theory of Catastrophism. A reactive power optimization techniques based on improved genetic algorithm (IGA) of wind farm is such presented. Simulation results for Chinese Mongolia Huitengliang Power Plant show that the proposed method has satisfied global performance, high convergence speed and stable convergence performance, so it is suitable to solve the optimal reactive power planning. [Copyright &y& Elsevier]

Abstract: With the development of multi-core technology, more and more servers adopt CPUs with multi-core to improve the performance. However, we couldn’t exploit the potential of multi-core system efficiently because traditional programs were developed and executed based on serial or very limited parallel mode. In this paper, a new application level parallelization model is proposed and applied to servers, which could parallelize the software at application level instead of relying on operating system level parallelization. By this mean, a simulation program, which is called ALPM, was developed. Experiments have been done to evaluate the new model, and the results show that the new model can improve the performance of multi-core system effectively, and avoid the problems of cache coherent and ping-pong effect. [Copyright &y& Elsevier]

Abstract: An improved spectral clustering approach based on differential evolution algorithm (DESC) is proposed in this paper. In our algorithm, we replace k-means with differential evolution (DE) as the final step in spectral clustering, thus it overcomes the deficiencies in sensitivity to initialization and local optima. Experimental results over artificial dataset and UCI dataset demonstrate DESC''s superiority in difficult clustering, steady performance and better accuracy. [Copyright &y& Elsevier]

Abstract: Particle swarm optimization (PSO) is an intelligent optimization technique, which has shown a good performance in many real world and benchmark problems. In this paper, we propose an improved PSO variant, called PSO with modified velocity strategy (MVPSO), in which each particle is attracted by the global best particle and a random particle chosen from a set of good particles. In order to verify the performance of MVPSO, ten well-known benchmark problems are used in the experimentas. Simulation results show that MVPSO obtains better performance than standard PSO and two other improved PSO variants. [Copyright &y& Elsevier]

Abstract: Differential Evolution (DE) is a recently proposed intelligent optimization algorithm, which has shown excellent search abilities in many real world and benchmark optimization problems. In order to enhance the performance of DE, this paper presents a hybrid DE algorithm, called HQDE, which employs a quantum-behaved mechanism and adaptive parameter control. To verify the performance of the proposed approach, ten well-known benchmark optimization problems were selected in the experiments. Simulation results demonstrate that HQDE obtains better performance than standard DE and another improved DE variant. [Copyright &y& Elsevier]