Key Engineering Materials Vols. 439-440

Abstract: To overcome the shortcomings of wired temperature and humidity measurement system, a temperature and humidity measuremet system based on wireless sensor networks was designed. the components of the system and its working principle were described in detail. Its nodes use a digital temperature and humidity sensor SHT15 for data collection, wireless transmission chip CC1100e for data short-range wireless transceiver and the wireless network, and AT89S52 microcontroller for controlling core. Nodes communicate with the background host through serial interfaces. The system can achieve environmental temperature and humidity dynamically and comprehensive real-time monitoring. Node has a dual function as terminals and routers, in addition to data processing, but also for other nodes to forward the temperature and humidity data storage, management, and integration, and taking in collaboration with other nodes to complete some specific tasks. The system has some advantages such as low cost, low power consumption and small size, which has a good application prospects.

Abstract: In recent years, logistics outsourcing has gained increasing importance and today is used by a large number of firms across virtually all industries worldwide. However, while logistics outsourcing brings enterprises economic benefits, it also brings in a lot of potential risks. It has an utmost significance to strengthen the identification and assessment of logistics outsourcing risks. The paper applies unascertained measure model to analyze and assess logistics outsourcing risks, which provides a new way to assess the risks of logistics outsourcing and is helpful for enterprises’ decision-making. Lastly, according to analysis results, the paper proposed aversion strategies for logistics outsourcing risks.

Abstract: Soil saturation degree plays an important role in mechanic behavior of soil-concrete interface. Laboratory experiments are conducted on soil-concrete interfaces by using improved simple shear apparatus, where three soil saturation degrees and five normal stresses are taken into accounted, respectively. The experiment data show that failure of the interface still satisfies the Mohr-Coulomb criterion under fixed soil saturation degree. With higher soil saturation degree, both shear strength and friction angle of the interface decrease monotonously, but cohesion force of the interface first increases and then decreases after reaching a peak value. When soil saturation degree increases, failure position of the interface moves from concrete surface to soil inner part.

Abstract: A new kind design scheme of sensing system for tire pressure monitoring system was introduced in this paper. In order to measure the condition of the tire in real time, MCU, MEMS sensor, thermometer, and wireless communication technology is used in this new system. The MEMS sensor and RF emitter was directly installed in tire. It was transmitted for receiver installed in cab by wireless after gas pressure data gathered. It sensed in time pressure condition by receiver, so that driver adopted corresponding countermeasure. The design of hardware and software is discussed in details.

Abstract: Aiming at the existing of a large number of distributed and heterogeneous application systems cross-application of rights management issues, the deficiencies of traditional rights management system, which in the aspect of the formal semantics supporting and reasoning abilities, are analyzed. In the rights management of cross-applications, the concept of domain ontology is introduced; a rights management system model is presented, which is based on the domain ontology cross-applications, for permission ontology to conduct a conceptual modeling and formal description of semantics, an increase of semantic reasoning ability, rich in the corresponding access control mechanisms to provide a user-friendly structure interface.

Abstract: This paper presents a solution of the Optimal Tolerance Design Problems for the production of power transformers. Based on statistical and probabilistic methods, it establishes a multi-objective and multi-constraint mathematical model. We then present a solution that maximizes the effective utilization rate of sheet material, for producing core columns of power transformers, and the passing rate of quality controls of matching coils and cores. It also minimizes the Tolerance cost of the product. The solution uses Particle Swarm Optimization (PSO), which is very effective as shown by simulation results.

Abstract: Based on fast multipole boundary element method (FM-BEM) and mixed variational inequality, a new method named mixed fast multipole boundary element method (MFM-BEM) was presented in this paper. In order to improve calculation time and accuracy, incompatible elements as interpolation functions were used in the algorithm. Elements were optimized by mixed incompatible elements and compatible elements. On the one hand, the difficult to satisfy precise coordinate was avoided which caused by compatible elements; on the other hand, the merits of MFM-BEM were retained. Through analysis of example, it was conclusion that calculation time and accuracy were improved by MFM-BEM, calculation continuity was also better than traditional FM-BEM. With increasing of degree of freedom, calculation time of MFM-BEM grew slower than the time of traditional FM-BEM. So MFM-BEM provided a theoretical basis for solving large-scale engineering problems.

Abstract: In order to improve the efficient and accuracy, parallel algorithm of fast multipole boundary element method (FM-BEM) was presented. Combined with sparse approximate inverse preconditioning (SPAI), GMRES(m) was used to solve the equation system of FM-BEM. The parallel FM-BEM was applied to strip cold rolling process, the results obtained from parallel FM-BEM was similar with the experimental measurements. The parallel FM-BEM has more efficient and accuracy than traditional FM-BEM. This method is benefit for solving precision engineering problem.

Abstract: With the implementation of electric power market, it is a difficult problem to provide the high quality and safety electric power, so, the electric power quality test is a key to solve it. Now, many electric power test system is designed by traditional single chip microprocessor with many disadvantages, we present a kind of method to realize based on virtual instrument (VI). System mainly designs upper PC management and test homepage index sub-system made by LabVIEW platform of VI software in this paper, aiming at disadvantage of existing test system without needed authority login module and management man-machine panel. This paper introduces part of system design method and practical result in detail. This system has stronger transplantation to other system because of modular design, which has broad practicality and application prospect.

Abstract: A robust trust model based on group for P2P environments-RobustGroup is put forward, which measures trust values based on the group relationship between requesting peers and serving peers. Trust’s aging time and peers’ similarity are introduced with weights for direct trust and indirect trust being dynamically adjusted in trust calculation against critical issues affecting trust evaluation such as false feedback, incentive and penalty, Whitewashing behavior, dynamic trust. Simultaneously service control policies are implemented on the basis of groups, and peers’ initial trust is determined by behavior in “silent time”. The simulation shows that the proposed model has advantages in successful requests and system overhead over the existing P2P trust models.