Advanced Materials Research Vols. 989-994

Abstract: Process mining is helpful for deploying new business processes as well as auditing, analyzing and improving the already enacted ones. The business process system log often has a large number of the namesake task and repetitive task. The existing alpha algorithm of the mining algorithm cannot distinguish them very well. It leads to the results that the process mining often produce inaccurate flow model. In order to improve the accuracy of the process mining, the paper puts forward an improved method. The new method not only can dig the complex structure, such as circulation structure, free choice structure and so on, it still can dig the eponymous task and repeat task in the log.

Abstract: Process mining is helpful for deploying new business processes as well as auditing, analyzing and improving the already enacted ones. This paper summarizes the scholars’ main studies in workflow mining, introduces the modeling process of two different kinds of mining algorithms in detail, compares and analyzes their performances, and explains the modeling process with an actual example.

Abstract: The technology of cloud computing has become a hot issue of research in the service of network in recent years. Cloud computing platform provide computing and storage services to customers. And it has been widely applied in e-business, e-education and etc.. While Cloud systems are usually hosted in large datacenters which may become a bottleneck to the system. In this paper we describe the design of a double-layer P2P model based on cloud computing. In the model, user nodes grouped into clusters form the Extended Cloud layer, and transfer file to each other without participation of the Core Cloud layer. The new model has better scalability and efficiency.

Abstract: Cloud computing deployment model has: IAAS, PAAS, SAAS, and they can provide calls for the clients by web services. REST-style cloud computing architecture represents resource by the URI, and operates resources by standard HTTP methods GET, PUT, POST, DELETE, etc. In this paper, the e-city website as example, using REST methods to architect website, logistics, customer, the pay bank. The architecture fully reflects the REST architectural style is simple and convenient. But REST flaw is that the limited transaction-oriented processing capabilities. In order to solve this problem, WASL (Web Application Description Language) is used to describe the REST API.

Abstract: Finite differencing is a very commonly method used in numerical algorithms to compute derivatives, which is well known for its accurate precision. Besides, the best advantage of this method resides in the fact that it is extremely easy to implement. But the finite differencing may be in a dilemma. The reason is that if the step size is large, the precision is not satisfying, but if the step size is small, the error is increased due to subtractive cancellation. In this manuscript, a new method for differential, complex-step differentiation (CSD) is proposed, which uses complex computations to compute derivatives. We first give a detailed account of the principles of the complex-step differentiation. Then analyze the CSD method from two sides, error and efficiency. At last, the implementation of CSD in MATLAB is presented. Simulating results indicate that they are fitting well with the theoretical analysis.

Abstract: This paper proposes an energy-efficient clustering routing algorithm based on the node degree, relative distance between nodes and residual energy. Selecting the cluster head fully consider the node degree and their relative distance. By this way, the coverage performance of cluster head is better and the average distance between member nodes and cluster head is short, so the cost of communication in the cluster is decreased. At the same time, the nodes with low energy have less probability to become the cluster head. Therefore, it can improve the quality of cluster; prolong the life time of the network.

Abstract: In practical applications of DSP systems, DSP chips with limited on-chip RAM resources are often chosen to reduce cost. In this condition, part of the codes has to be stored in FLASH or expanded RAM and thus can not run at full speed. This paper presents a strategy of allocating the on-chip RAMs to obtain the maximum system performance. First, the memory allocation problem is described as the knapsack problem, and then the greedy algorithm is applied. Experimental results show that the overall execution efficiency can be improved by 10% when the on-chip RAMs are rather limited. Therefore, the proposed memory allocation method is efficient for low-cost design to obtain higher performance.

Abstract: Ultra-low-bit-rate speech coding algorithm was in great demand for many fields such as underwater speech communications. Underwater speech communication for middle-long distance has the characteristics of narrow bandwidth as well as low transmission rate, which makes the underwater speech communication much difficult. Ultra-low-bit-rate speech coding algorithm plays an important role on this occasion. More over, it will be more flexible for the underwater speech communication system if the speech coding algorithm has an embedded structure. The paper introduced the principle of an embedded speech coding algorithm with dual rates at both 300bps and 400bps based on the enhanced mixed excitation linear prediction model. The results show that this embedded ultra-low-bit-rate speech coding algorithm has satisfactory quality under both DRT and MOS test.

Abstract: Materialized view is an important topic in data warehouse research, and also affects the query efficiency and maintenance cost. The disk-space view-selection problem is to select a set of materialized views for the purpose of minimizing the total query processing cost and the total maintenance cost. In this paper we introduce evolutionary algorithm using stochastic ranking algorithm, which can enable materialized view selection under disk-space constraint. The algorithm improve the stochastic ranking algorithm, which can find a near-optimal feasible solution. This paper use the algorithm in Police data warehouse.

Abstract: Image segmentation is the key step in the process from image processing to image analysis. Otsu method is one of the most successful methods for image thresholding because of its simple calculation. Otsu method can select threshold automatically and divide the object from the background in the image. In this paper, various Otsu algorithm are studied.