Advanced Materials Research Vols. 1044-1045

Abstract: Based on the analysis of mobile learning, with web technology application network course in computer application technology of Dongguan Polytechnic as an example, design and implementation of mobile learning terminal platform of network course based on Android ,states the whole process of analyzing, design and implementation of this system. This system supports network course of m-learning by developing Android application program, which offers a new way of actualization of network course and has practical and popularizing value.

Abstract: With the economic development, coal mines internal communications began to appear and gradually gained popularity and development. This paper firstly analyzed the coal enterprise intranet LAN communications requirements, and then overviewed the UDP meaning and application and designed and implemented UDP-based coal enterprise LAN communications software, which achieved good results.

Abstract: EBG structures can greatly reduce mutual coupling effects between patch antennas by suppressing surface wave propagation in a specified frequency range. A two-annular rectangular slot EBG structure is proposed and its performance is analyzed. HFSS simulation results show that mutual coupling loss in a 2x2 patches system is reduced appreciably (10dB in the work frequency band 19.6~22GHz (K/Ka band)) compared with antenna without EBG structures. What’s more, the side effects on other performances, like reflection parameter and bandwidth, are so little that can be neglected. With this EBG structure loaded in antenna array, the systematic performance can also be improved.

Abstract: During the past two decades, most studies have employed questionnaires to characterize the effects of noise on behavior and health. Developments in physiological techniques have provided a noninvasive method for recording cardiovascular autonomic activity by using an electrocardiogram (ECG). We investigated cardiovascular activity changes in exposure to exposure to low-frequency noise for various noise intensities by using detrended fluctuation analysis (DFA) of heart rate variability (HRV). We hypothesized that distinct noise intensities would affect cardiovascular activity, which would be reflected in the HRV and DFA parameters. A total of 17 healthy volunteers participated in this study. The test intensities of noises were no noise, 70-dBC, 80-dBC, and 90-dBC. Each noise was sustained for 5 minutes and the ECG was recorded simultaneously. The cardiovascular responses were evaluated using DFA of the beat-to-beat (RR) intervals obtained from ECG signals. The results showed that the mean RR intervals variability and mean blood pressure did not substantially change relative to the noises. However, the short-term scaling exponent (α₁) of the DFA of the background noise (no noise) condition was lower than the 70-dBC, 80-dBC and 90-dBC noises (P < 0.05, repeated measures analysis of variance). The α₁ of 90-dBC noise was significantly higher than the α₁ of BN condition according to a Mann–Whitney U test (P < 0.01). We concluded that exposure to low-frequency noise significantly affects the temporal correlations of HRV, but it does not influence RR intervals variability.

Abstract: This paper designed and implemented a driver of CAN bus based ARM Cortex-M3. Combined with CAN bus technology, the paper introduces the hardware design based on STM32F205, a latest 32 bits microchip and CAN transceiver SN65HVD232. The design of CAN communication protocol and the program of software are described. The relevant key technology such as initialization, interrupt and data structure are illuminated. Experiments have verified the CAN bus driver is feasible, stabile and reliable.

Abstract: With the increasing requirement on flattening the hierarchical structure of the military command networks, this paper studied the efficiency of the cross-level command style which is one of the most way to flatten current structure. We present a cross-level command model based on the tree network. According with it, we focused on two measurements, timeliness and invulnerability, to evaluate the command networks on different cross-level by the simulation experiments. Compared the results under two styles of attack strategies, the random attack and selecting attack, it showed that the new command networks with different cross-level are more efficient.

Abstract: The paper mainly expounds the concept of embedded system, development process and its application in the set-top box, finally introduces the development trend of the embedded system.

Abstract: Shaking leaves has been the biggest interference for early forest smoke video detection. Moving average method, Gaussian mixture method and its improved methods are often used to update background, but the performance is not good through background subtraction. Codebook algorithm is applied to extract foreground for early forest smoke detection, quantization techniques are used to obtain background model from time series, then getting foreground image through background subtraction. Through multiple video tests, the experimental results that the filtering performance, anti-noise performance and accuracy are better than other methods above.

Abstract: In this paper, a new face recognition method based on eigenface image reconstruction and Fisherface is proposed, it is mainly used to reduce the loss of personal characteristics. First, we can obtain the feature subspace of all the classes in training set by using the inner-classes covariance matrix as generating matrix, and so we get the eigenfaces of each person (class). Next, we use the principal component of testing set, which is obtained by mapping testing set to the feature subspace, to reconstruct the testing images. Finally, we substitute the reconstructed testing images for the original ones, and then get the recognition work completed by using Fisherface method. The simulation illustrates the effectivity of the method on the ORL face database.

Abstract: Data centers comprised of racks and corresponding servers form the backbone of today’s cloud computing. Continuous operation of large numbers of servers can generate large amounts of heat which in turn requires high capacity cooling systems. These cooling systems can consume a significant portion of the energy required to run a data center and can negatively impact data center efficiency. With increasing operational costs, the data center industry has started to actively search for efficiency improvements to slow down the rising cost of running services. One of the most prominent ways to cut power consumption is free cooling, which uses outside air for cooling IT equipment completely or part of the time. This system is often used in colder climates and requires less energy since it doesn’t use compressors for cooling incoming air. This paper presents an evaluation of Shanghai as a data center location. As temperature affects data center cooling consumption, focus of the paper is on evaluating optimal operating conditions for local data centers.