Advanced Materials Research Vols. 225-226

Abstract: In this paper, we analyze the DCF and PCF schemes, and study some conventional MAC algorithms. For the purpose of satisfying requirements of data transmission in integrated services, a new MAC algorithm based on working vacations is proposed in the paper. Using the continuous system simulation strategy, we design the simulation experiment of MAC algorithm. Combining queuing theory, the steady performance parameters of queuing model is obtained. The results show that the algorithm based on working vacations has an advantage over single PCF or DCF scheme in some indices such as mean queue length, mean delay time and system throughput.

Abstract: The walking motion state of biped robot with knee is analyzed, the system model is established based on the walking phase; for the stability of passive walking gait is poor, The limit cycle convergence domain is smaller and sensitive to interference. Energy control and angle invariant control is merged, A steady gait is produced at different angles on the ground by the angle invariant control, the gait limit cycle convergence domain is expanded by the energy control method, the energy control gain is adjusted by nonlinear function. The simulation result shows that the method can expand the limit cycle convergence domain and increase the robustness.

Abstract: Personalized web information recommendation service had becoming an important research task increasingly as the time goes by. This paper established user profiles and put forward a recommendation strategy. On the base of these, the paper designed a personalized web information recommendation system based on data mining, namely, PWIRS. The experimental results indicate that the recommendation strategy of PWIRS is feasible.

Abstract: The article collected radiation intensity of TIG arc plasma in different dimensions and analyzed arc spectrum by establishing horizontal scanning system of plasma. Choose Fe and Ar characteristic spectral line as the subjects; acquire the distribution of arc radiation in different dimensions through Abel conversion; calculate temperature of plasma using Boltzmann. The results indicated that the position of strongest radiation is about 1mm from the tungsten pole, then it gradually weakens along the radial direction and the gradient of Ar spectral line is greater. The lowest temperature is near the base metal and the highest one is near tungsten pole.

Abstract: Based on idealized non-steady state transient heat conduction model, the thermal conductivities of apple samples were determined at various moisture contents by using a specifically designed apparatus. The apparatus is rapidly, simply, accurately and only has relatively small sample requirement. Experimental data of thermal conductivities of apples showed a tendency of linear increase with the increase of moisture content of apple sample at the same temperature. An empirical correlation model for the thermal conductivity of apple as a function of moisture content was obtained. The developed model can be used to predict the thermal conductivity of apple satisfactorily in the entire range of moisture content. The results can be better contributed to the food engineering application.

Abstract: Register and discovery of education resource is the key to effective share education resources. Only based on resource register and discovery, other applications may be realized . Based on the existing discovery mechanisms, this paper proposed the model of hierarchy education resource classified register and discovery in grid. Puts forward to the register and discovery algorithm of education resources, and made a simulation test using GridSim.

Abstract: In a mobile ad-hoc network, MANET, designing a security routing protocol is an important issue since the mobile nodes and wireless medium are prone to be attacked. However, most of wireless routing protocols concentrated on how to reduce the data transmission time and energy consumption. Wireless routing paths in MANET may be broken or fabricated by attacking. Hence, sending data packets to the destination may failure. For defending the active black hole attacks and the passive fabricated routing attacks, we proposed a preventive security mechanism based on ad-hoc on-demand distance vector routing (AODV), called PSM-AODV. PSM-AODV modified some field in RREQ, RREP, and RERR packets based on AODV. PSM-AODV thus may defend the possible black hole and fabricated routing attacks. Simulation results showed that PSM-AODV could promote the packet delivery rate based on little overhead in control packets.

Abstract: An overall shifting device was designed to move the drill as a whole, avoid the repeated assembly and disassembly of the cluster wells drill. The hydraulic system of the device and the strength of the loaded parts of the system was checked; The earth anchor, the size of the earth anchor was determined and ANSYS analysis were conducted to ensure its supporting function.

Abstract: In the article, functional requirements need to be analyzed for Chongqing four manufacturing execution systems in cold-rolled steel production line. Combined with the idea of design of the system it can be proposed overall design of information systems and network topologies. Meanwhile, it can also be designed technology and production performance modules based the ERP system platform. Focus on design the production performance of functional modules and interface combined with 1450 actual production process. Production data to be collected need to be establishing the simulation model of the node .Do achieve the simulation of the actual production process. Meantime, the simulation data will be collected to the production performance module through the interface with the real-time database. Chongqing four steel companies as state Enterprises, it should be attached great importance to enterprise information. It has not basically realized the bottom of the production process control system, but also the initial establishment of the upper information management system. However, the underlying automation system and upper management information systems are not integrated. This situation seriously affects the application of effective information systems. The method can only deal with the current manual operations, which leads to the following series of questions: the basis of the data delay line failure; Based data acquisition product line transmission efficiency is low and error rate is high; Production site data scattered in many different processes link manually using the original production data acquisition and transmission are difficult to track products from production through to finished off the assembly line of the whole process; Top manufacturing information system based on production data can not directly access to hard to complete implementation of its functions. In response to these problems, Chongqing four steel companies build MES system, marketing integration, the information management systems and process control systems integration as a whole, and thus the implementation of ERP systems and decision support systems, and further enhance their core competitiveness.[1,7]

Abstract: The objective of this study is to investigate and evaluate the effect of fine aggregates (aggregate size smaller than or equal to 2.36 mm) on the compressive strength and creep behavior of asphalt mixtures. The variables that are considered in the study include the sizes and gradations of fine aggregate. A kind of standant aggregate gradation and four kinds of reduced aggregate gradation mixture specimens are used. Uniaxial compression and static creep tests were realized at different loading conditions. The test results showed that the different fine aggregate sizes do not result in significant differences in compressive strength and creep values using the same percentage of fine aggregates (38.4%). Only the different gradations showed a little differences for mixtures made with different gradations but same aggregate size (between 2.36 and 1.18 mm).