Applied Mechanics and Materials Vols. 58-60

Abstract: This paper describes the complexity and particularity of the trajectory of tube-sphere intersection and derives mathematical model of the track; according to characteristics of B-Spline curve, the track intersecting curve is partitioned ,and determine the mathematical relationship between the control points (deBoor point) and the data points of J-type groove; using cubic non-uniform irrational B-Spline theory, generate segments of approximation curves, then first and last point of each segment are constrained, so that combination curves can be seen as a whole curve with C¹ continuity; programming the trajectory of the preprocess module with C# language, it has advantages of approximate accuracy and high efficiency, thereby it can increase accuracy and precision of welding terminal position, so that the overall system has a metronomic characteristic.

Abstract: Considering the complexity and decentralization of data acquisition and power supply for cockpit devices of flight simulator, this paper designs and realizes a distributed simulation system for aircraft cockpit based on embedded Ethernet and Power over Ethernet technology. A simulation scheme with many nodes of data acquisition and instrument control is adopted. Based on PoE technology, the power subsystem can supply DC power on the same cable that carries data. As a result, this greatly simplifies power wiring installation in the narrow cockpit while improving reliability. The design of aircraft cockpit simulation has been successfully used in certain type flight simulator. Through the actual system testing, the design has excellences of higher stability, expansibility and security.

Abstract: Under the learning automaton frame a bionic self-learning automaton which has autonomous learning mechanism is constructed based on conditioned reflex theory. The bionic self-learning automaton is a 5-tupe and mainly contains: 1) inner set, mainly are perception state set and operant set; 2) oriented core, guide the direction of autonomous learning; 3) learning core, the primitives of learning unit; 4) autonomous learning unit, implement learning computation; 5) operant entropy, measuring the self-organized degree of bionic self-learning automaton. Theory analysis is made for the designed bionic self-learning automaton in the thesis, which theoretically proves the convergence of autonomous learning mechanism in bionic self-learning automaton, namely the operant entropy will converge to minimum with the learning process. And then the designed bionic self-learning automaton which used as the mathematical abstraction and formal tool of robot and used to describe the self-learning behavior of robot is applied to motion control of two-wheeled self-balanced robot. The state sets of bionic self-learning automaton is described by tilt angle and tilt angle rate of robot, and the operant sets is described by control signal of left motor and right motor. Robot doesn’t have t motion balanced skill in initial state, and with the learning proceeding the operant entropy will gradually decrease. After about twenty-five rounds training, the operant entropy gradually tends to minimum. So robot gradually learned the motion balanced skill.

Abstract: The present Extraction for Keyword in Chinese (EKC for short) is merely directed against explicit keywords or prototype keywords, and has not take into account those tacit keywords distorted by network hackers with the method of active jamming in Chinese. For this purpose, with the help of M. Polanyi’s theory of tacit knowledge, this paper presents a new approach for the tacit EKC (TEKC for short), which can improve the ratio of precision and recall for information filtering. Based on the TEKC, the paper presents a set of classifications of how to distort the explicit keywords and the solutions to calculate the tacit distortion of those tacit keywords. Furthermore, 4 algorithms were designed, including in picture tacit, textspeak tacit, fake paleography tacit and character tacit, which can extract the tacit keywords in text but traditional EKC could not. Owing to the increased number of extracted keywords, the recall of keywords raised and the precision of information filtering improved. Experiments show that the classification of tacit keywords in Chinese, the calculation of tacit distortion and the algorithms to tacit extract the keywords in Chinese, etc can effectively improve the performance of EKC and raise the recall of web filtering algorithms based on TEKC.

Abstract: Aiming at the wide application of technological design in three-dimensional CAD software, while the technological dimension chain’s calculation is completed in the two-dimensional process sketch still. A sort of method of calculating technological dimension chain was put forward, which is based on three-dimensional process model. Three-dimensional process model is created through the process of technological design by introducing the concept of three-dimensional process model, and then, the information of process dimension is extracted from the three-dimensional process model and a tree oriented process dimension structure is established. On the basis of the above, we can proceed with technological dimension chain’s integrated calculation and analysis, redistributing the process dimension and its corresponding allowance dimension and tolerance. It will offer more reasonable and reliable process parameters to the technologists in the design of process route, and also effectively solve the problems of the technological dimension chain’s calculation involving to CAPP system in the environment of three-dimensional CAD software.

Abstract: In this paper, we focus on IEEE 802.11e enhanced distributed channel access (EDCA) protocol, which can provide QoS guarantee for multimedia applications in mobile ad hoc networks. First, we briefly explain the concept of EDCA protocol. Then we implement EDCA protocol in GloMoSim via configuring special contention parameters for multimedia applications and introducing a virtual collision disposal mechanism in the MAC layer. In the end, we provide performance analysis for EDCA protocol through plentiful simulations. The simulation results show an excellent performance of the EDCA protocol we proposed.

Abstract: Functional modeling is the key step in product design process. To improve the quality of functional modeling, an identification method of key elemental function based on function-failure knowledge was proposed. A function-failure knowledge model for mechanical product was built, which consists of function-failure mode, relationships among failure modes, and failure risk information. By means of the function-failure repository, the approach to calculate risk number (RN) of the elemental function was presented, in which the relationships among failure modes were considered. Then the key elemental functions were identified by the RN value. Finally, a case was studied to illustrate the proposed method.

Abstract: This paper proposes a computational grid platform for solving the large-scale power system applications. The platform is based on Globus Toolkit middleware and GridWay meta-scheduler. It can enable large-scale sharing of computational resources across institutional boundary. This paper first discusses the architecture and each component of the platform, and then the test bed is described. Finally, the test results of probabilistic load flow (PLF) by Monte-Carlo simulation are presented. The test results show that the computational Grid system can provide comparable performance.

Abstract: Spatial resources such as slipway and erection platform are key and bottleneck resources for large equipment manufacturing enterprises, and restrict output and efficiency of enterprises. Spatial resource has several distinct features, such as spatiality, divisibility, adjacency, exclusivity and group characteristic. These features introduce great complexities into spatial Resource Constrained Project Scheduling Problem (sRCPSP), which lead sRCPSP very hard to model and solve. So a mathematical model for sRCPSP considered all features and other renewable resource constrains comprehensively has been established. Then an Activity Type Priority based Serial Scheduling heuristic method and a Resource-Time Block based Spatial Resource Allocation Method have been proposed to solve the model. Results of numerical experiments proved that those two algorithms are correct and effective.

Abstract: Wavelet analysis has been the focus of active research for twenty years, both in theory and applications. In this work, we develop the concept of a class of multiple vector-valued trivariate wavelet wraps with a dilation matrix. A new method for constructing multiple vector-valued trivariate wavelet wraps is proposed. Their characters are investigated by means of operator technique, time-frequency analysis method and matrix theory. There orthogonality formulas regarding the wavelet wraps are provided. Orthogonality decomposition relation formulas of the space L²(R³, C^r×r) are obtained by constructing a series of subspaces of the multiple vector-valued wavelet wraps. Furthermore, several orthonormal wavelet wrap bases of space L²(R³, C^r×r) are constructed from the wavelet wraps. The pyramid decomposition scheme is obtained based on such a GMS and a sufficient condition for its existence is provided. Relation to theoretical physics is also discussed.