Search

Hadoop is a popular software framework supports distributed processing of large data sets. However, with Hadoop being a relatively new technology, practitioners and administers often lack the expertise to tune it to get better performance. Hadoop parameters configuration is one of the key factors which influence the performance. In this article, we present a novel Hadoop parameters tuning method based on function monitoring. This method monitors the function call information during task run to analyze why the performance of Hadoop changes when tuning parameters, which will be helpful for practitioners and administer to tune parameters to get better performance.

The research work, Ascertaining the connection type between evaporating tube bundle and a steam drum shell on a Natural Circulation marine supercharged boiler, is important. For this reason the method, calculating the low-cyle fatigue life of supercharged boiler steam drums put forward by Xin-wei Zheng, et al., was put to use; Based on the relevant basic data from design department and two typical running conditions of one supercharged boiler, the cumulative fatigue damage ratio of welding technique was calculated. The calculated result proves that it exceeds the maximum value of 1.0 and the upper limit value of 0.75 in fossil-fuel power plants, respectively. So welding technique can’t guarantee the low-cycle fatigue life of this steam drum, the only connection type is expanded joint, and the connection type has been put into practice.

Based on optimized aquatic diatom medium, treatment of nutrient deficiency was carried out to Navicula sp. and the analysis results of comprehensive biomass and total lipid content indicated that the optimal Tmass concentrations of TFeClB3B·3HB2BO,T TCdSOB4 Band Citric acid were 1.2×10P-5P mol/L, 0.8μg/L and 12 mg/L, respectively. Maximum biomass of Navicula sp. on this culture medium at 680 spectrophotometrically could reach 1.201. Final lipid content of this microalgae could be improved from 26.60% to 37.68% after the stress of nutrient deficiency treatment.

In the various colleges and universities of China, university computer foundation course will be offered to the freshman of all majors. In order to combine the needs of the development of computer application domain, the author carried out reform and practice on university computer foundation course. The reform and practice Include faculty construction, the construction of teaching materials, the innovating in teaching mode and methods, the reform of teaching methods and means, the reform of assessment methods, network teaching resources development and other aspects. Through a variety of ways of learning, students can more easily grasp the necessary basic computer knowledge, be equipped with strong computer practice ability to meet requirements for computer operation in learning, work and daily life in the future.

In order to realize highly intelligent and automatic species identification and recognition, we obtained the images of 11 varieties and each variety includes 50 seeds. For each image, we acquired 33 characteristics including shape, color and texture characteristics. And then we constructed the Artificial Neural Network and Support Vector Machine model to train and identify different varieties. We built the recognition system based on Visual C++ 6.0 and OpenCV library.Results shows that the SVM method has higher recognition effect than neural network overall and the recognition effect is more stability, the overall self-_recognition performance can reach 100% and test accuracy can reach 85%. The recoginition System base on Visual C++ runs faster than that of Matlab, which is more suitable for real-time varieties identification.

This paper illustrated the teaching status of packaging experiment in colleges and universities, discussed feasibility of constructing virtual packaging lab on the basis of virtual instrument and information control , introduced hardware structure and software module of virtual packaging lab in detail, and analyzed development of virtual instrument for temperature measurement under liquid filling through examples. Moreover, packaging lab can be constructed with the lowest cost and the utilization rate of experimental instrument can be increased through virtual instrument; this is an important development direction for packaging lab.

Image mosaic (Mosaic) for a given image sequence is the first image sequence alignment positioning, and then fusion spliced to produce a seamless, high-resolution large-scale scene images. This paper discusses the calculation model in the wavelet transform in image processing and wavelet transform image stitching. This paper presents the optimal image mosaic method based on Wavelet transform and introduces a seamless optimization algorithm based on wavelet transform and its validity through a concrete example simulation.

To measure the applicability of the cement mixing method in the reinforcement of soft clay in Jiaozhou Bay, laboratory test of cement-stabilized soil with different mixture ratio are conducted. We take fly ash as additive and have studied the influences of the cement types, cement content, additive content, soaking time and other factors on the cement-stabilized soil strength under the groundwater soaking condition. This paper demonstrated a link between the above factors and cement-stabilized strength.

In order to obtain accurate and high-speed data transmission, the orthogonal frequency division multiplexing(OFDM) technology is introduced and it is a kind of a multi-carriers modulation technology with high efficiency in the use of frequency band and characteristics of strong anti-interference ability. The fractionally spaced OFDM frequency domain equalization algorithm based on modified pilot sequences is proposed. In this proposed algorithm, one-dimensional linear interpolation method is used to estimate the frequency domain response of all subcarriers by part of the subcarriers’ frequency domain response with reducing the number of transmitted pilot sequences, and received signals are oversampled to acquire more detailed channel information. The computer simulations in underwater acoustic channel show that the performance of proposed method outperforms the single-carrier system and traditional OFDM system.

All rock mass engineering projects are closely related to rock mass material property. The methods of obtaining these properties decides the project design’s safety and reasonable. The varied characteristics of rock mass under force are subjected by their texture, construction and tectonic history. The experimental results imply that the rock mass strength, deformation and failure modes are all effected by following aspects, including the test controlling method, machine stiffness and the sample size, etc,. In order to use the test results to guide the practice projects, we must first know the natural status and engineering propagation process of rock mass, then design suitable experimental scheme, subsequently, the more fit for the natural results of rock changed process will be appear. According to the analysis of previous research achievement and newly test results, we can investigate the rock mass stability and predict its failure.