Search

In order to solve the problem that it is difficult to configure reasonably for the equipment maintenance material in each maintenance level, this paper proposes a method based on simulation modeling for the equipment maintenance material configuration considering with the complex relationship of various elements and the randomness of various maintenance activities. A basic simulation system framework is proposed to realize the more accurate demand for maintenance equipment which can be difficult for the traditional mathematical modeling and description. Finally the proposed model can lay the foundation for the optimal allocation of maintenance support resources in the future.

With its rich varieties and unique features, decorative glass has a great impact on the creation of indoor light environments. It may influence multiple aspects such as the color and amount of light, the relationship between light and shadow, and the dimension of the whole space. In this paper, decorative glass is studied in reference to its innovative applications in the world, thereby providing certain inspiration for staff in the design industry.

Wear is the main cause of failure of gear transmission system. In order to solve the problem that it is difficult to extract fault features from complex environmental noise for condition recognition, this paper proposes a method based on EEMD and INPP for gearbox wear condition recognition. Firstly, EEMD method is used to decompose the original vibration signal of gearbox, and then the decomposition results are sorted by kurtosis criterion, and the components with large kurtosis index are selected for time-frequency domain analysis to get the time-frequency domain high dimensional feature set; then the improved Neighborhood Preserving Project (INPP) algorithm is used to reduce the dimension of high-dimensional features, and then the reduced dimension features are obtained for state recognition. Finally, the algorithm is verified by the vibration response data of gearbox and compare with several algorithms, and the results show that the proposed algorithm has stable dimensionality reduction effect, good classification effect, and shows the effectiveness of the method.

Multi-core architectures have become mainstream. Trends suggest that the number of cores integrated on a single chip will increase continuously. However, lock contention in operating systems can limit the parallel scalability on multi-cores so significantly that the speedup decreases with the increasing number of cores (thrashing). Although the phenomenon can be easily reproduced experimentally, most existing lock models are not able to do so. To overcome this challenge, this paper develops a discrete event simulation model which has the capability of capturing both the sequential execution in critical sections and the contention for shared hardware resources. The model is evaluated using a series of typical parameter configurations which can represent different degrees of lock contention. Experimental results suggest that the thrashing phenomenon can be observed when the model parameters are selected properly. To further understand this phenomenon, statistics such as the percentage of time spent waiting for locks and the number of cores waiting for a lock are exploited to characterize the lock thrashing. In addition, the model sensitivity to changes in memory latency and hardware architectures are also examined. Finally, we use this model to compare three methods which are proposed for preventing the lock thrashing.

Multi-core architectures have become mainstream. Trends suggest that the number of cores integrated on a single chip will continue to increase. However, lock contention in applications or kernels can degrade the scalability so significantly that the speedup decreases with the increasing number of cores (thrashing). Although the phenomenon can be easily reproduced on real multi-core platforms, existing lock models are not able to do so. To overcome the disadvantage, this paper proposes an analysis model which has the capability of capturing both the sequential execution of critical sections and the overhead of lock implementation. Numerical results indicate that thrashing can be observed by using the proposed model. Furthermore, this model can also be exploited to compare different mechanisms designed for avoiding the lock thrashing.