Applied Mechanics and Materials Vols. 44-47

Abstract: A new multi-dimensional index structure called RSR-tree is proposed, which based on RS-tree. In RSR-tree, index records of a leaf node are split to ensure the sequence ordering of index records in a leaf node, which reduces the addressing cost of I/O operations effectively when reading data files. The entries of a non-leaf node are split to decreases the overlap between the brother nodes, which reduces effectively the time of reading data from data files. Experimental results on different data sets show that compared to RS-tree, RSR-tree has better comprehensive performance, in regard to tree building and querying. The querying performance is increased and extra cost is not produced.

Abstract: In this paper, a generalized multivalent fuzzy measure of extensional L-measure, called high order extensional L-measure, is proposed. It is proved that if the value of order index is equal to one, this new measure is just the extensional L-measure, and the larger the value of order index is, the more sensitive it is. A real data set with 5- fold cross-validation MSE is conducted, for comparing the performances of the Choquet integral regression model based on this new measure with other four measures, P-measure and λ-measure, and authors’ two measures, L-measure and extensional L-measure, and two traditional regression model, multiple regression model and ridge regression model, the result show that the Choquet integral regression model based on this new measure has the best performance.

Abstract: Sine bar is a practical accurate measuring implement which can measure indirectly or a machining tool for the accurate angle by sine principle. The effect of sine bar manufacturing accuracy on angle measurement is expounded by the angle measurement and calculation of the sine bar in this paper. Then the conclusion can be drawn that the angle can be get by measuring the length accurately through sine bar, and measuring a small-angle by sine bar which can reach the higher accuracy.

Abstract: A new type of automatic verification apparatus based on image recognition is put forward in this paper. Data are acquired by CCD camera through digital image processing. The length reference is provided by the precision grating. Verification and data processing are completed by computer. The apparatus has features of high accuracy and precision, good reliability, efficiency and convenience in operation. The errors caused by artificial factors are lowered.

Abstract: After a coal mine disaster, especially a gas and coal dust explosion, the space-restricted and unstructured underground terrain and explosive gas require coal mine rescue robots with good obstacle-surmounting performance. This paper tackles path-planning or collision avoidance problem. The collision avoidance problem in path planning of mobile robots was inspired from fuzzy control concept. The deduction of the path-planning algorithm is followed. Fuzzy rules and fuzzy inference based on experiences is built, it constructed a reasonable and applicable control reactive rule table. The simulation results are presented to validate the approach. And it is also proved that the control arithmetic is available in both static and dynamic obstacles in coal mine environment.

Abstract: Flame simulation in computer graphics has been the most challenging problems. According to the key problem of real time and reality in flame simulation based on particle system, a new flame model based on improved particle system and the texture mapping is proposed in this paper. This article uses specific geometric shape as the elementary particles and combines treatment of derivatives based on the flame of the original particle system to simplify some of the dynamic equation, to reduce the difficulty of computational modeling and improve rendering speed; Through texture mapping and particle mixing effects to achieve flame changes color in different regions and reflect the temperature difference between them; In addition, the method also reflects the dynamic field of the particle system.

Abstract: In this paper we propose the notion of unified resource base to simplify the resource exchange, sharing, and access, especial for e-learning. To illustrate the feasibility and advantages of such a unified resource base, we also design and implement a uniform resource management system (URMS). We discuss its functionalities, present its architecture, and demonstrate how its components can be implemented based on current technologies.

Abstract: Reinforcement learning (RL) is a state or action value based machine learning method which approximately solves large-scale Markov Decision Process (MDP) or Semi-Markov Decision Process (SMDP). A multi-step RL algorithm called Sarsa(,k) is proposed, which is a compromised variation of Sarsa and Sarsa(). It is equivalent to Sarsa if k is 1 and is equivalent to Sarsa() if k is infinite. Sarsa(,k) adjust its performance by setting k value. Two forms of Sarsa(,k), forward view Sarsa(,k) and backward view Sarsa(,k), are constructed and proved equivalent in off-line updating.

Abstract: The incorporation of zirconium atoms into the framework of some aluminosilicate molecular sieves can enhance the reactivities of some typical strong Brønsted acid needed reactions, and the strengthening of Brønsted acidity were regarded as one possible reason. In this study, the effects of zirconium incorporation on the Brønsted acidity of zeolite with CHA structure were characterized by means of periodic density functional theory (PDFT) calculations. Results from deprotonation energy and NH3 adsorption energy are consistent and show that no significant acidity enhancement is found in comparison to Zr-free sample. The results indicate new catalytic mechanism should exist.

Abstract: The damage of the printed wring assembly (PWA) was treated as one of the main factors of the failure of electronic equipment. Thus the PWA must be studied and investigated. As the important prerequisite of the study, the dynamic characteristics of the PWA were determined in this paper. Here the dynamic characteristics of the PWA were modeled and analyzed by finite element analysis (FEA) method firstly, and then the experimental modal analysis (EMA) method was also used to study the dynamic characteristics of the PWA. The results obtained from above two methods were compared with each other, and good correlation was shown. So the correctness and accuracy of the FEA model was verified. On the base of that, the Z-axis (the normal of the board) of the PWA was determined as the main direction to be excited; subsequently the main modes in that direction were also determined. Furthermore the principle described as the components crossed by bend lines are detrimental to solder joint survival was used to prognosticate the packages which may be damaged.