Advanced Materials Research Vols. 204-210

Abstract: With Multi-channel MAC protocols, transmission pairs can send data packet simultaneously. Hence, higher network throughput can be achieved. The developing of 802.11s standard provides the power saving model multi-channel MAC protocol (PSM-MMAC) framework, which divides into negotiation phase and data phase. All the users select appropriate channels to transmit data in dedicated channel during negotiation phase, then the users will switch the transceivers to the selected channel to transfer data packet by RTS/CTS handshake. While taking the size of data window constraints, therefore how to design the data packet size is the key issue of PSM-MMAC in saturation network case. In this paper, we propose a new policy that can adjust the size of data packet based on the channel occupancy and the fairness of user access for unsolicited Grand Service, which has strict requirements on the delay jitter and maximum reserved traffic rate. We also develop the probabilistic statistical analysis model to compare the performance of previous policy and our proposed policy. Simulation results verify our analysis model, and show our policy has the superior performance of the PSM-MMAC to the previous scheme.

Abstract: The sea surveying is one of the branches of surveying, and the sea navigational affairs project construction belongs to the sea survey application category. This paper mainly introduces the application of GPS technology in the sea navigational affairs project construction. Taking the Nantong ocean mouth artificial island project as the example, analyzing and studying the application of GPS using on the steel sheet pile implementing the localization during the navigational affairs project, and introducing the prime tasks of the steel sheet pile implementing the localization in detail, the specific procedures as well as the questions which should be paid attention in the work process and the methods of solving the questions, also summarizing some experiences of GPS using in the steel sheet pile implementing the localization.

Abstract: Based on Darcy - Weisbach route losses equation, this test is focused on the mixed-flow problems at low speed in big flow field, designing the experiment scheme, introducing its principle, and setting up the test rig. According to the test result data, we put forward the definition of flow speed coefficient and draw its curves, and described some related issues, such as reverse pressure phenomenon，reliability of flow simulation, roughness, and so on. The results showed that the flow speed in the pipe will get higher with the flow field increasing, and smaller relative roughness pipes. The flow speed coefficient x≤1 and its curves is monotone decreasing function and will be closer to a fixed value at last with V₀’s increasing. This test will provide theoretical basis for increasing fluid energy’s utilization.

Abstract: Acylated anthocyanins synthesis with anthocyanins extract from black rice and Octenyl succinate anhydride(OSA) was performed in pure ethanol. Stability of acylated anthocyanins and the color change have been evaluated over pH (1.0–12.0), light (daylight) and temperature(to 98°C) conditions, showing higher stability than non-acylated anthocyanins. The Acylated anthocyanins extracts showed red coloured solutions up to pH 10. However, The extracts from anthocyanins were observed faded to yellow after pH values up to 7. The increased stability of anthocyanins together with change in solubility opens a new window of opportunities for use of these extracts in a variety of food applications.

Abstract: Air fuel ratio is a key index affecting power performance and fuel economy and exhaust emissions of the gasoline engine, whose accurate model is the foundation of accuracy air fuel ratio control. In the paper, at first, it has studied the Elman neural network (NN) simulation model of Air Fuel ratio physical model of automotive engine. Second, employing the SI-V8 in en-DYNA engine model as experimental device, the paper discussed the structure determination of Elman neural network; finally, it compared model identification performance between Elman and BP neural network. Experiment results show the generalization performance of neural network does not have a linear relationship to the neurons in hidden layer of Elman NN, and the air fuel ratio based on Elman neural network is better than the air fuel ratio model based on BP neural network. The average relative error of Elman NN air fuel ratio model is less than 0.5%, however, which of BP NN is more than 1%.

Abstract: Recently, the CR (cognitive radio) technology is gathering more and more attention because it has the capacity to deal with the scarce of the precious spectrum resource. Within the domain of CR technology, channel management of CR is of utmost importance due to its key role in the performance enhancement of the transmission. A group-based DCA (dynamic channel allocation) MAC protocol in CR network has been proposed in this paper. It divides the channels into several groups which consist of the data channels and common control channel. We analyze the throughput under saturation condition, and the simulation results show that by using our protocol the throughput is improved obviously compared with traditional DCA.

Abstract: General-purpose processors continue to improve computing performance, but its energy consumption has far exceeded the increase in the proportion of performance. Specifically designed for the special purpose processor in the case of relatively low power consumption, can provide better performance. The general-purpose processor as the main control unit, special purpose processors as accelerators consisting of heterogeneous supercomputers will become a trend in supercomputer development. This paper introduces and analyzes several heterogeneous supercomputers used to build the acceleration components.While accelerate parts based on such components have obvious calculation advantages (high computing power, low power consumption), but with less application and difficult programming bottlenecks still exist. After all, the application number is limited which using hundreds, thousands or even more parallel computing for good expansion performance, and the workload of migration, development and optimization remains high.

Abstract: With the rapid development of computer technology, database technology is becoming an important branch of the computer field, it is increasingly being used in e-commerce, Web services, information systems, etc., database technology research has become necessary. This paper describes the development process of database technology, and then lists a number of measures to optimize database performance, and finally on the future development trend of the database are discussed.

Abstract: With the rapid development of Internet, online shopping is becoming a new way for shopping. However, the security of online shopping has been the focus by a lot of people worried. This article discusses the existing problems from the online shopping area and the integrity of the security of online transactions, and describes the corresponding solutions. Finally, an example of information encryption technology introduced in the simple online shopping application.

Abstract: As to current situation of research on production scheduling under uncertainties in enterprises, Flow Shop production scheduling model is established based on the theory of fuzzy programming, in which fuzzy processing time is considered and the duration time of intermediate is unlimited. The maximum membership function of mean value has been applied to solve the non-linear fuzzy scheduling model in order to convert the fuzzy optimization problem to the general optimization problem. Finally, a cooperative co-evolutionary particle swarm optimization algorithm based on catastrophe added to improve the diversity of the swarm (CCPSO) is adopted to solve Flow Shop Production Scheduling Under Uncertainty within Infinite Intermediate Storage and results are obtained effectively.