检索结果-南通市图书馆

Concurrent collision probability of RFID tags in underground mine personnel position systems

在线全文

学校读者我要写书评

暂无评论

Mining Science and Technology 2010年第5期20卷 734-737页

作者： JI Yuchu,XU Zhao,FENG Qinzhu,SANG Yuan School of Information & Electrical Engineering,china university of Mining & Technology,xuzhou 221008,china School of Information&Electrical Engineering China University of Mining&Technology Xuzhou 221008 China

According to the basic requirements of underground mine personnel position systems and the working characteristics of active RFID tags,we studied the cause of concurrent collision of RFID tags and leak reading probability,by means of theoretical analysis and *** result shows that the probability of wireless collision increases linearly with an increase in the number of *** probability of collision and leak reading can be reduced by extending the working period of the duty cycle and using a backoff *** a practical application,a working schedule for available labels has been designed according to the requirement of the project.

关键词： personnel position system RFID collision probability of RFID tag

Constraining the characters of the upper mantle discontinuities beneath the NE margin of the Tibetan Plateau with a dense broadband seismic array

在线全文

学校读者我要写书评

暂无评论

Science china Earth Sciences 2020年第3期63卷 425-438页

作者： He HUANG Xuzhang SHEN xuzhou LIU Yuansheng ZHANG Lanzhou Institute of Seismology China Earthquake AdministrationLanzhou 730000China School of Earth Sciences and Engineering Sun Yat-Sen UniversityGuangzhou 510275China

Based on observations from a dense broadband seismic array located along the northeastern (NE) margin of the Tibetan Plateau in southeastern Gansu Province,we use receiver functions (RFs) to pick the arrival times of P-to-S converted waves and bin the traces in different grids according to the piercing points of the 410 and 660 km discontinuities in the upper *** depths of the two discontinuities are estimated by the ray tracing method with the IASP91 velocity model and a 3.D tomography *** results indicate the following:(1) The arrival times of the P410s and P660s converted phases are delayed by approximately 1 s than those predicted by the IASP91 *** mantle transition zone (MTZ) is thicker than that in the global model.(2) The synchronous lags in the P410s and P660s arrival times are consistent with low-velocity anomalies in the upper mantle,which are believed to result mainly from the eastward migration of materials beneath the NE margin of the Tibetan Plateau.(3. Combined with previous tomography results,the depression of the'660'discontinuity and the thickened MTZ are somewhat consistent with the big mantle wedge (BMW) ***,due to data limitations,more studies are required to explore the BMW in the future.

关键词： NE margin of the Tibetan Plateau Upper mantle discontinuities Low-velocity anomalies Receiver functions

The Design of Image Compression Algorithms Testing and Analyzing Tool

在线全文

学校读者我要写书评

暂无评论

微计算机信息 2007年第18期23卷 254-257页

作者： (School of Computer, china university of Mining and Tech- nology, Jiangsu xuzhou 221008, china)Zhang Hong Kong Li Fang Cai Zheng- Xing (xuzhou Air Force College, Jiangsu xuzhou 221008, china) Kong Li Fang School of Computer china university of Mining and Technology Xuzhou Jiangsu Xuzhou 221008

This paper studies the evaluation methods for image compression algorithms and proposes test methods for compression algo- rithms including horizontal comparison test and vertical decomposition test. On the base of this, we design and realize a testing and analyzing tool for performance of image compression algorithms. This tool can test and analyze compression algorithms and generate kinds of analysis chart automatically, provides a lot of convenience for users and has very important practical value. In order to im- prove efficiency, veracity and perfectibility of the tool, this paper presents selection method for test images and analysis method for test results which have certain theoretical meaning.

关键词： Compression Performance Testing method Analyzing method Image Selection method

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

文件传输的遗传算法优化研究

数据采集与处理 2003年第2期18卷 146-150页

作者：刘西奎徐州师范大学工学院徐州221011

给出了文件传输问题的边着色模型。遗传算法是一种借鉴生物界自然选择和进化机制发展起来的高度并行的、随机搜索算法 ,具有自适应性。为了求解文件传输问题 ,文章在引入一种新的自适应性的交换概率和变异概率的基础上 ,提出了一种面向... 详细信息

给出了文件传输问题的边着色模型。遗传算法是一种借鉴生物界自然选择和进化机制发展起来的高度并行的、随机搜索算法 ,具有自适应性。为了求解文件传输问题 ,文章在引入一种新的自适应性的交换概率和变异概率的基础上 ,提出了一种面向求解文件传输问题的遗传算法。提供了遗传算法的结构并讨论了遗传算子。本文给出了一个例子说明算法的收敛性和收敛效率 ,仿真结果表明了算法的有效性。

关键词：遗传算法优化文件传输运筹学贪婪算法

Characteristics of acoustic emission signals in damp cracking coal rocks

在线全文

学校读者我要写书评

暂无评论

Mining Science and Technology 2010年第1期20卷 143-147页

作者： TANG Shoufeng, TONG Minming, HU Junli, HE Xinmin School of Information and Electrical Engineering, china university of Mining & Technology, xuzhou 221008, china School of Information and Electrical Engineering China University of Mining & Technology Xuzhou 221008 China

A uniaxial load experiment on coal rocks at different stress rates was carried out, based on the characteristics of acoustic emission (AE) signals in cracking coal rocks, decomposition, de-noising and reconstruction for the AE signals through wavelet packet transform for solving the current problems created by the presence of noise in AE signals and the existing problems in AE signal processing. The results show that the various characteristics of AE signals in coal rocks cracking under different situations can be clearly reflected, after the AE signals are de-noised by the wavelet packet. Compared to dry coal rocks, the number of AE occurrences in damp coal rocks was significantly reduced, as well as the average amplitude. The number of AE occurrences in damp and dry coal rocks clearly increased with increases in the loading rate, but the largest amplitude of the AE signals in damp coal rocks has been reduced. There is no clear evidence of change in dry coal rocks.

关键词： coal rocks cracking Acoustic Emission (AE) signal processing wavelet packet analysis de-noising

Fault diagnosis using a probability least squares support vector classification machine

在线全文

学校读者我要写书评

暂无评论

Mining Science and Technology 2010年第6期20卷 917-921页

作者： GAO Yang, WANG Xuesong, CHENG Yuhu, PAN Jie School of Information and Electrical Engineering, china university of Mining & Technology, xuzhou 221116, china School of Information and Electrical Engineering China University of Mining & Technology Xuzhou 221116 China

Coal mines require various kinds of machinery. The fault diagnosis of this equipment has a great impact on mine production. The problem of incorrect classification of noisy data by traditional support vector machines is addressed by a proposed Probability Least Squares Support Vector Classification Machine (PLSSVCM). Samples that cannot be definitely determined as belonging to one class will be assigned to a class by the PLSSVCM based on a probability value. This gives the classification results both a qualitative explanation and a quantitative evaluation. Simulation results of a fault diagnosis show that the correct rate of the PLSSVCM is 100%. Even though samples are noisy, the PLSSVCM still can effectively realize multi-class fault diagnosis of a roller bearing. The generalization property of the PLSSVCM is better than that of a neural network and a LSSVCM.

关键词： fault diagnosis probability least squares support vector classification machine roller bearing

Analysis on Tribological Properties of Potentially New Friction Material with Response Surface Method

在线全文

学校读者我要写书评

暂无评论

Journal of Wuhan university of Technology(Materials Science) 2011年第3期26卷 499-503页

作者：徐蕾 School of Mechanical and Electrical Engineering China University of Mining & Technology

The tribological properties of newly developed friction material were evaluated by statistical analysis of the major affecting *** material for investigation was non-metallic friction material synergistically reinforced with aramid fibre and CaSO 4 whisker,which was developed for hoisting applications in coal *** response surface method（RSM）was employed to analyze the material performances affected by the independent and interactive effect of the factors under the normal working condition and severe working condition,*** showed that under the normal working condition,the newly developed material exhibited stable tribological properties which were insensitive to the test *** under the severe working condition,the sliding velocity was the most dominant factor affecting the friction ***,compared to the commercially available material,the modified material showed superior wear resistance and thermal stability.

关键词： tribological properties friction material response surface method wear

Implementation of a multiple round quantum dense coding using nuclear magnetic resonance

在线全文

学校读者我要写书评

暂无评论

Science china(Physics,Mechanics & Astronomy) 2005年第6期48卷 706-715页

作者： ZHANG Jingfu1, XIE Jingyi2, WANG Chuan1, DENG Zhiwei3. LU Zhiheng4, & LONG Guilu1,5 1. Key Laboratory For Quantum Information and Measurements of MOE, Department of Physics, Tsinghua university, Beijing 100084,china 2. Department of Materials Science and Engineering, Beijing normal university, Beijing 100875, china 3. Testing and Analytical Center, Beijing normal university, Beijing 100875,china 4. Department of Physics, Beijing normal university, Beijing 100875, china 5. Key Laboratory For atomic and Molecular Nanosciences, Tsinghua university, Beijing 100084,china Key Laboratory For Quantum Information and Measurements Department of Physics Tsinghua University Beijing 100084 China Department of Materials Science and Engineering Beijing Normal University Beijing 100875 China Testing and Analytical Center Beijing Normal University Beijing 100875 China Department of Physics Beijing Normal University Beijing 100875 China Key Laboratory for Atomic and Molecular Nanosciences Tsinghua University Beijing 100084 China

A multiple round quantum dense coding scheme based on the quantum phase estimation algorithm is proposed and implemented in a three qubit nuclear magnetic resonance (NMR) quantum computer. Using an m + 1 qubit system, Bob can transmit one of 2m+1 messages to Alice, through manipulating only one qubit and exchanging it between Alice and Bob for m rounds. The information capacity is enhanced to m + 1 bits as compared to m bits in a classical scheme. The scheme has been demonstrated in NMR system, and the experimental results show a good agreement between theory and experiment.

关键词： quantum dense coding, multiple round, nuclear magnetic resorance

Theoretical study on the reaction mechanism of(CH_3._3.O+CO

在线全文

学校读者我要写书评

暂无评论

Science china Chemistry 2005年第1期48卷 18-24页

作者： ZHAO Hongmei1,2,3. SUN Chengke1,4, ZHANG Rongchang3. XI Hongmin3.& LI Zonghe1 1. Department of Chemistry, Beijing normal university, Beijing 100875, china 2. The Laboratory of Molecular Reaction Dynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080, china 3. Department of Chemistry, Beihua university, Jilin 13.013. china 4. Department of Chemistry, Qujing normal university, Yunnan 655000, china Department of Chemistry Beijing Normal University Beijing China The Laboratory of Molecular Reaction Dynamics Institute of Chemistry Chinese Academy of Sciences Beijing China Department of Chemistry Beihua University Jilin China Department of Chemistry Qujing Normal University Yunnan China

The reaction mechanism of (CH3.3.O with CO has been theoretically investigated using density-functional theory (DFT) calculations at B3.YP/6-3.G* level. In order to get more reliable energy values the single-point energy is evaluated at CCSD (T)/6-3.++G** level. The results show that the reaction is multi-channel and the reaction of (CH3.3.O radical with CO mostly produces (CH3.3. + CO2. The reaction could play a role in eliminating air pollution.

关键词： DFT, B3.YP, (CH3.3.O, radical.