Advanced Materials Research Vols. 204-210

Abstract: The fractal characteristic of microstructure in semisolid A356 alloy was researched by the calculating program written to calculate the fractal dimensions. The results indicated that the morphology of primary grain in semisolid A356 prepared by compound process is characterized by fractal dimension, and the morphology of primary grain at the different position of ingot had the different fractal dimensions, which reflected the effect of solidified conditions at different position in the same ingot on the morphology of semisolid primary grain.

Abstract: A pit experimental investigations on elastic modulus of the dn160 steel-plastic composite pipe are carried out in the paper. The experimental results show that the elastic modulus of steel-plastic composite pipe is 10.93 GPa. In order to verify the pit experimental, buried-heating experiments are conducted. It was found that the deviation is within 6%. The excellent agreement indicated that the elastic modulus data by pit experiment are reliable and can be used as basic data for directly buried heating pipeline design.

Abstract: Computer simulation is an important method in the study of cardiac electrophysiology. However, complicated studies in tissues are difficult because of the long computation time. In order to speed up the simulation, in this paper a parallel algorithm based on OpenMP was studied on a multi-core computer. The Noble 91 mathematical model was used to develop a two-dimensional tissue. By initiating a reentrant wave, properties of the conventional sequential program, programs of the data parallelism and functional parallelism were analyzed and compared. The results showed that the execution time of the data parallelism was only about one-fourth of the sequential execution time and its efficiency was high, however, the execution time of the functional parallelism was approximately ten times of the sequential execution time and its efficiency became low. Therefore, the method of the data parallelism could significantly reduce the computation time and was suggested to be a good choice in the myocardial simulation.

Abstract: The group-buying online, a boom of e-commerce phenomenon, expands rapidly in China. Hence, the evaluation of group-buying website is essential for CEO to improve their website performance and for consumers to select the platform to purchase. However, the evaluation of group-buying website is a multiple-criteria decision making (MCDM) problem that is not easy to determine. For this reason, we propose analytical hierarchy process based approaches Fuzzy AHP, to evaluate the group-buying websites. In addition, a case study is presented to demonstrate how the approach can help in solving such problems in practice.

Abstract: Traditional resource scheduling algorithm, in grid environment, exist some defects, for example it can not well meet the quality requirements and can not get the optimal solution. This article gives a new resource scheduling method based on improved genetic algorithm. It achieves grid resource scheduling by using real number encoding and activities point crossover. Experiments show that genetic algorithm can reduce executing time and task completion time, and further improve the scalability of resource scheduling model. This algorithm has stability and high efficiency in grid environment.

Abstract: Indoor positioning system in wireless local area network (WLAN) has been a subject of intensive research due to its cost effectiveness and reasonable positioning accuracy. A new WLAN indoor positioning algorithm based on support vector regression (SVR) and space partitioning is proposed. The whole positioning environment is partitioned into several subspaces by combining k-means clustering method and binary support vector classifiers (SVC). Then the mapping function between received signal strength (RSS) and the physical space is established by SVR machine for each subspace. Subspace with much smaller physical range means more compact input feature space and leads to the enhancement of generalization capability for each SVR machine. The proposed algorithm and other well-known positioning algorithms are carried and compared in a real WLAN environment. Experimental results show that the proposed algorithm achieves 14.6 percent (0.31m) improvement than the single SVR algorithm in the sense of mean positioning error.

Abstract: Effective information sharing mechanism is a very important part of the supply chain. For the supply chain of chained enterprises based on e-commerce, we use the game theory to analyze the necessity of information sharing. The incentive model of information sharing for the participators of the supply chain is proposed based on the given cost and weighing of each participator.

Abstract: This paper discusses a new kind of mode in database design——mode of “column changes line”. This paper discusses the definition of the mode, and in detail analyses the mode through specific cases, and summaries its specific advantage and applied scenes. In the end of the paper, it discusses the relationship between the mode and four-atomization theories in database design.

Abstract: This paper discusses a new kind of pattern to database design——pattern of strong entity infringing. This paper in detail analyses the pattern through two specific cases, and summaries its specific applied scenes. In the end of the paper, it discusses the relationship between the pattern and the four-atomization theories to database design.

Abstract: This paper discusses four-atomization theories to database design, which are property atomization, Entity atomization, the primary key atomization, Relationship atomization, and explains why these theories are great development of normalization theory to database design.