Applied Mechanics and Materials Vols. 556-562

Abstract: With the development of information technology, distributed file system is widely used in massive information storage. Usually, distributed file system uses metadata server to achieve quick access to files according to directory, thus the organization and management of metadata are the keys to the file system performance. In general, directory subtree partition method and hash algorithm are used by existing mass storage system to manage metadata. However, to solve the problems, like low access efficiency of metadata, ineffective balance of load and poor extensibility, in existing metadata management strategy of distributed file system, dynamic load balance strategy of metadata based on hash tags is put forward, in which the tags act as partition granularity and hot tags of metadata will be hashed again to achieve the goal of load balance. The experimental results in this paper turn out that modified metadata management strategy based on hash tags has greater system throughput and less average response time than the one based on tags.,

Abstract: On account of low convergence of the traditional genetic algorithm in the late,a hybrid genetic algorithm based on conjugate gradient method and genetic algorithm is proposed.This hybrid algorithm takes advantage of Conjugate Gradient’s certainty, but also the use of genetic algorithms in order to avoid falling into local optimum, so it can quickly converge to the exact global optimal solution. Using Two test functions for testing, shows that performance of this hybrid genetic algorithm is better than single conjugate gradient method and genetic algorithm and have achieved good results.

Abstract: Text segmentation is very important for many fields including information retrieval, summarization, language modeling, anaphora resolution and so on. Text segmentation based on PLSA-TextTiling associates different latent topic swith observable pairs of word and sentence. In the experiments, the whole sentences are taken as elementary blocks. PLSA model is used to calculated similarity metric basing on the idea of TestTiling and several approaches to discovering boundaries are tried. The results show the Pμ value is 0.87, which is better than that of other algorithms of text segmentation.

Abstract: In this paper, a modification BFGS method with nonmonotone line-search for solving large-scale unconstrained optimization problems is proposed. A remarkable feature of the proposed method is that it possesses a global convergence property even without convexity assumption on the objective function. Some numerical results are reported which illustrate that the proposed method is efficient

Abstract: Combining the Guangdong LNG station project, the gas station consumption instrument air equipment were analyzed, and the calculation of gas station instrument air system gas storage tank capacity, according to the Guangdong LNG station, the special circumstances, calculate separate switching valve gas storage jars. Through the analysis of the calculation process and result, relevant design wind instrument system is put forward.

Abstract: People’s attention of transformer condition assessment is increasing in recent year and data mining is applied in transformer condition assessment with its obvious superiority in dealing with complex data and finding potential problems. In this paper, the process of the research on applying data mining to transformer condition assessment is summarized. The research results of data processing methods such as rough set theory, principal component analysis and colony algorithm as well as the research result of transformer condition assessment such as vector machine, neural network, Bayes network, association rules and fuzzy theory are introduced, analyzed and compared in detail. The advise on the choice and quantification of figure, the employ of the pattern recognition method, the blend of multi-information and visualization display are given.

Abstract: This paper develops a model to provide reasonable predictions on Earth’s health condition.Factors that influencethe health condition of each nodeareanalyzed by Analytical Hierarchy Process and Vector Projection Theory is used to calculate shift matriceswhich reflect the interaction between nodes. Also the earth’s overall health condition is shown in this model.The prediction made in the test fits well with the reality.Finally, we analyze sensitivity of our model and find out critical and tipping points in the network. This information can be used for the policy making. We also use an example to show how the local policy influences on the global health condition.

Abstract: In real application areas, the dataset used may be highly imbalanced and the number of instances for some classes are much higher than that of the other classes. When learning from highly imbalanced dataset, the classifier tends to be adapted to suit the majority class, which might make classifier to obtain a high predictive accuracy over the majority class, but poor accuracy over the minority class. To solve this problem, we put forward a novel graph based semi-supervised learning method for imbalanced dataset, called GSMID. GSMID characterize the class equilibrium constraint as the smoothness of class labels. It’s expected to derive the optimal assignment of class membership to unlabeled samples by maximizing the correlations of classes and simultaneously as smooth as possible on instance graph. The experiments comparing GSMID to SVM and other graph based semi-supervised learning methods on several real-world datasets show GSMM can effectively improve the classification accuracy on imbalanced dataset, especially when data is highly skewed.

Abstract: Aiming at improvement of the dynamic performance of in-wheel-drive electric vehicles, an approach to coordinate wheel slip ratio tracking with fulfilling driver’s desired torque is presented. First, an anti-windup PI controller for slip ratio tracking regardless the unknown ground adhesion, is proposed, followed by its stability analysis base on Lyapunov theory. Second, a coordinating logic is designed to guarantee that the slip ratio tracking control engages only when driver’s desired tracking or braking motor torque may cause the wheel to spin or lock. The performance of the control strategy is supported by simulation and experimental results.

Abstract: To make products understood by users more easily, it has become a hot topic in industrial design that how to fill the gap of semantic cognition differences between designers and users. In this paper, users’ cognition process is built and analyzed, a concept of abstracted symbol is proposed. Then different kinds of shape information are abstracted into simple shape symbol. At last, a rational mapping between users’ cognitive concept and product shape information is built up. This mapping model provides designers a way to know better about the users’ cognition, thereby guides designers to design product shape more rationally.