Key Engineering Materials Vols. 439-440

Abstract: Companies set the highest standards of working together throughout the supply chain to create value and sustainable competitive advantage. Trust plays a most important role in the cooperation of supply chain. This study provided an effective method to evaluate the priorities on factors for partnership in supply chain. The factors which affect the trust partnership were setup and an evaluation model was built. Analytic Network Process was used to compute the priority of factors.

Abstract: The relation between R&D input and patent output in Chinese software firms is empirically analyzed. Estimations from both time series data and cross-section data show that there is a significantly causal and quantitative relation between the R&D input and the patent output in Chinese software firms, and the R&D input has leg effects on the patent output. By calculating the output elasticity it is found that Chinese software firms have stepped into the era of knowledge economy, but their human capital remains homogenous. From the composition of the source of R&D capital input it is inferred that in the macro level market-demand has become a major source of these firms’ technological innovations.

Abstract: OFDM（Orthogonal Frequency Division Multiplexing）is a new modulation technology, which can reduce multi-pass interference efficiently. It splits a high-rate data stream into a number of lower-rate data streams which can be transmitted simultaneously over a number of subcarriers. It brings high spectral efficiency. In this paper, we first introduce the channel estimation algorithm based on comb-pilot in OFDM system, and emphasis on analysis and comparison of the three kinds of interpolation methods: linear interpolation, low-pass interpolation and transform-domain interpolation. We use MATLAB to carry out the system simulation, and its results indicate that: The performance of low-pass interpolation is the best ,but it’s hard to carry out; transform-domain interpolation’s performance and complexity are both between above two methods.

Abstract: It is a significant challenge to design a secure routing protocol for wireless sensor network (WSN), because a WSN has dynamic topology, limited energy, confined computing ability and small memory size. This study explores the algorithm of ensuring security in routing layer for a WSN. In this paper, a multipath secure routing protocol for flat network--MDMP is proposed. Symmetric encryption and asymmetric encryption are exploited to encrypt and authenticate data in the network. Furthermore, malicious nodes will be detected out and isolates. Experiments show that MDMP provides effective immunity to a variety of attacks in WSN and better network performance.

Abstract: In this paper, a new congestion controller is developed to obtain a feedforward and feedback optimal control for networked control systems (NCS) with persistent disturbances. The disturbances have known dynamic characteristics but unknown initial conditions. The disturbance observer is proposed to make the feedforward control law realizable physically. In the approach only the non-linear compensating term, solution of a sequence of adjoint vector differential equations, is required iteration. By taking the finite iteration of non-linear compensating term of optimal solution sequence, a suboptimal control law for NCS with time delay can be obtained.

Abstract: According to the seismic analysis of the soil mechanics for the major and complex geotechnical engineering projects such as highway, high-speed railway, subway, dams and so on, there is acute lack testing instrument considering the level earthquake load and the vertical earthquake load. In order to resolve this problem a new design plan is putted forward in this paper, which can generate bidirectional exciting force with designed amplitude ratio, phase and waveform. The radial exciting subsystem (water pressure) and the axial exciting subsystem (force) are both built by the hydraulic servo systems. The two subsystems have excellent dynamic response characteristics. Several key technical issues existing in bidirectional exciting control have been discussed in detail such as: (1) high-precision unconventional bidirectional exciting control strategy; (2) decoupling control methods in the bidirectional exciting process; (3) real-time compensation by using digital image technology. The instrument will provide advanced test conditions for the complex geotechnical engineering.

Abstract: Chinese air traffic passenger volumes have experienced phenomenal growth during the past years. The air traffic volume prediction plays a key role in air traffic flow management system. This paper develops a hybrid model of Neural and Grey Theory for air traffic passenger volume forecasting. The Grey theory is adopted to fit the air traffic data patterns and make the data a higher regularity, and Radical basis function is combined to raise the forecasting accuracy. The model is tested with the Chinese civil aviation passenger volume data from 1998 to 2007 and the result shows that the model is feasible for practical implementations.

Abstract: . DDA（Digital Differential Analyzer）circular interpolation algorithm is often applied to NC（Numerical Control） machining trace control, due to the greater error accumulation in DDA interpolation algorithm, the maximum feed speed of machine tool is limited, and the interpolation algorithm is hardly satisfied with the requirements for high-precision and high-speed machining. To solve this problem, a new circular interpolation algorithm based on the angular approximation method was proposed, the fundamental rule, calculation program and calculating process were introduced, and then, this interpolation algorithm was compared with the other DDA interpolation algorithm in error accumulation. It is concluded from comparative analysis and practical application that the new interpolation algorithm does not exist any accumulative error in the speed and outline, the interpolation error is little, the algorithm is simple and easy to be realized as well.

Abstract: Point-by-point comparison interpolation algorithm is often applied to NC （Numerical Control）system, however，there are some problems such as lag in phase, out of step and low-speed crawl for higher feed velocity（ ≥3000mm/min）in multi-axes synchronous machining system, which influences response velocity and interpolation precision of NC system. In view of this， based on the point-by-point comparison principle , the midpoint interpolation algorithm for deviation judgment in NC machining trace control was proposed, mathmatical model of interpolation established, the deviation judgement function of the interpolation algorithm improved and optimized. It is shown from comparative analysis and practical application of midpoint interpolation algorithm that the interpolation precision raises from 1 to 0.5 pulse equivalent, interpolation points reduce greatly, response velocity quickens and interpolation precision heightens as well.

Abstract: Evaluation is an important and basic issue for software dependability. However, traditional researches mostly focused on the conceptions and properties of dependability, which resulted in lots of different views about software dependability. Based upon Pi Calculus, dependable action path of software and real action path are set up through series of actions, which is decomposed by running software behaviors. In addition, three kinds of relationships between behaviors are defined. Consequently, the dependability is calculated by comparing the real running software actions to the decomposed ones based on the defined relationships. Experimental result conducted by MWB shows that the proposed method in one behavior is reasonable. At last, a real experiment proves the proposed measure method is more valid than traditional one.