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Search Results: 1 - 10 of 42362 matches for " Ke Zhou "
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Kinematical Analysis and Simulation of High-Speed Plate Carrying Manipulator Based on Matlab  [PDF]
Ke Wang, Jiping Zhou
Engineering (ENG) , 2012, DOI: 10.4236/eng.2012.412108
Abstract: In order to construct the more effective kinematics method for industry, by taking a high-speed plate handing robot as an example, the structure and parameters of the robot linkages are analyzed, and the standard Denavit-Hartenberg method is applied to establish the coordinates and the kinematic equation of the linkages. Depending on the graphics and matrix calculation ability of Matlab especially including the Robotics Toolbox, the handling robot has been modeled and its kinematics, inverse kinematics and the trajectory planning have been simulated. Therefore, the correctness of kinematic equation has been verified, meanwhile, the functions of displacement, velocity, acceleration and trajectory of all the joints are also obtained. In a further step, this has verified the validity of all the structure parameters and pro- vided a reliable basis for the theoretical research on the design, dynamics analysis and trajectory planning of the ma- nipulator control system.
The Impact of Police Work-Family Conflict on Turnover Intentions: The Roles of Organizational Support and Job Burnout  [PDF]
Jianglin Ke, Jialin Zhou, Wenhua Zhu
Open Journal of Social Sciences (JSS) , 2019, DOI: 10.4236/jss.2019.74001
Abstract: Work-family conflict is always considered to have a positive influence on job burnout and turnover intentions. But things may be different for Chinese police, who may be less likely to leave their job because of their firm beliefs and higher welfare. Considering this, we use Beijing police as the sample of our research, and explore the impact of work-family conflict on turnover intentions under the roles of organizational support and job burnout. By analyzing 316 valid questionnaires surveyed from the Beijing public security system, we get the following conclusions: work-family conflict and job burnout have a significant and positive correlation with turnover intentions; job burnout plays a partial mediating role in the relationship between work-family conflict and turnover intentions; organizational support plays a moderating role between work-family conflict and job burnout.
The Analysis of Several Models of Investment Value of Logistics Project Evaluation
Ke Qiu Cheng Zhou
Economics Research International , 2013, DOI: 10.1155/2013/412725
The Analysis of Several Models of Investment Value of Logistics Project Evaluation
Ke Qiu Cheng Zhou
Economics Research International , 2013, DOI: 10.1155/2013/412725
Abstract: The study of the logistics project evaluation model features reviews the traditional value evaluation model. On the basis of this, using the fuzzy theory, we establish several logistics project evaluation models under fuzzy environment. The analysis of the respective characteristics and the comparison of the calculated results of the three models show that these models are important methods of investment value of logistics evaluation. 1. Introduction With the use of information technology and e-commerce and other modern technology, the investment in logistics industry has high uncertainty, irreversibility, and fuzziness. The application of NPV and other traditional methods of logistics project valuation is easy to cause the enterprise objective and actual value deviation. Giving full consideration to market volatility, uncertainty, irreversibility, and real option is of great practicality. The application of the real option to evaluate logistics project investment value is widely used. Schwartz and moon [1] believe that real option in venture capital evaluation can make better explanation. Dayanik [2] and so forth solved the one-dimensional diffusion process of optimal stopping problems, and the results for American option pricing, control, and so on are suitable. At the same time, in view of logistics project investment also having the characteristic of fuzziness, fuzzy factors with real option theory to carry on the research is very important. Carlsson and fullér [3] considered the rates of fuzzy-relation-fuzzy-option formula and used the optimization theory to build the project investment decision model of R&D optimization. The fuzzy process, mixing process, and uncertain process proposed by Liu [4] can well explain the fuzzy financial market. Qin and Li [5] also presented the option pricing problem under fuzzy environment. Although most of the distribution function of a random variable can be obtained by statistical method, but in actual, because of the incomplete logistics project information and prior knowledge, we often fail to accurately collect and measure these data and cannot depict or control the various factors of the logistics project, which increase the logistics project management fuzzy. Thinking about these factors of the logistics project completely, many scholars are considering the classical option pricing theory on how to be improved. This paper reviews the logistics project evaluation model under traditional situation, then, on this foundation, it puts forward a few other value evaluation models and discusses and finally compares
Hitting Time Distribution for Skip-Free Markov Chains: A Simple Proof
Wenming Hong,Ke Zhou
Mathematics , 2013,
Abstract: A well-known theorem for an irreducible skip-free chain with absorbing state $d$, under some conditions, is that the hitting (absorbing) time of state $d$ starting from state 0 is distributed as the sum of $d$ independent geometric (or exponential) random variables. The purpose of this paper is to present a direct and simple proof of the theorem in the cases of both discrete and continuous time skip-free Markov chains. Our proof is to calculate directly the generation functions (or Laplace transforms) of hitting times in terms of the iteration method.
A note on the passage time of finite state Markov chains
Wenming Hong,Ke Zhou
Mathematics , 2013,
Abstract: Consider a Markov chain with finite state $\{0, 1, ..., d\}$. We give the generation functions (or Laplace transforms) of absorbing (passage) time in the following two situations : (1) the absorbing time of state $d$ when the chain starts from any state $i$ and absorbing at state $d$; (2) the passage time of any state $i$ when the chain starts from the stationary distribution supposed the chain is time reversible and ergodic. Example shows that it is more convenient compared with the existing methods, especially we can calculate the expectation of the absorbing time directly.
Tail asymptotic of the stationary distribution for the state dependent (1,R)-reflecting random walk: near critical
Wenming Hong,Ke Zhou
Mathematics , 2013,
Abstract: In this paper, we consider the $(1,R)$ state-dependent reflecting random walk (RW) on the half line, allowing the size of jumps to the right at maximal $R$ and to the left only 1. We provide an explicit criterion for positive recurrence and the explicit expression of the stationary distribution based on the intrinsic branching structure within the walk. As an application, we obtain the tail asymptotic of the stationary distribution in the "near critical" situation.
Access Control for Manufacturing Process in Networked Manufacturing Environment  [PDF]
Ke Zhou, Min Lv, Gang Wang, Bingyin Ren
Journal of Service Science and Management (JSSM) , 2009, DOI: 10.4236/jssm.2009.22014
Abstract: The deficiencies of current access control techniques in solving the problems of manufacturing process access conflict in networked manufacturing environment were analyzed. An information model of manufacturing process was con-structed, and a case XML Schema of manufacturing task model was given. Based on the characteristic analysis of the access control for the information model, an improved access control model of manufacturing process was constructed, and the access control model based on manufacture tasks, roles and time limits and the relationships among the ele-ments were defined. The implementation mechanisms for access control model were analyzed, in which the access case matching strategy based on manufacture tasks and time limits, the authorization assignment mechanism based on manufacture tasks, roles, correlation degrees and time limits, XML based access control for transaction security and integrity were included. And the two-level detection architecture of transaction conflict was designed to find the con-flicts both in application and in the database. Finally the prototype system was developed based on these principles. Feasibility and effectiveness of the method were verified by an enterprise application.
Voltammetric Study of the Interaction between Melamine and DNA on a Carboxylic Acid-Functionalized Nano-Fe3O4 Modified Electrode and Its Analytical Application for Melamine Determination in Liquid Milk Samples  [PDF]
Ke Chen, Haoyu Shen, Zhejun Wang, Amen Zhou, Qinghua Xia
American Journal of Analytical Chemistry (AJAC) , 2015, DOI: 10.4236/ajac.2015.64025
Abstract: Carboxylic acid-functionalized nano-sized magnetic composite polymers (COOH-NMPs) were synthesized and used for the preparation of the modified glassy carbon electrode, i.e., COOH-NMPs/GCE and DNA/COOH-NMPs/GCE. The electrochemical behaviors of melamine (MM) were investigated on COOH-NMPs/GCE by cyclic voltammetry (CV) in both cases of DNA in the solution and immobilized on the electrode surface. The electron transfer coefficient (a) and the rate constant (ks) kept unchanged in the absence and presence of DNA. Based on the electrochemical properties of the interaction of MM on the surface of the DNA/COOH-NMPs/GCE, a direct method for the determination of MM in liquid milk was established. The detection limit of this method was 2.0 ng·L1, with average recoveries at 95.9% - 104.2% and RSD at 4.5% - 8.2%. The proposed method was provided to have a good accuracy, high stability and good reproducibility with a simple and environmental friendly process. 10 kinds of liquid milk samples bought from the market randomly were tested, and only 1 of them was found at relatively low level of MM residue with the amount of 0.12 ug·L1.
Fossils of Quercus sect. Heterobalanus can help explain the uplift of the Himalayas
ZheKun Zhou,QingSong Yang,Ke Xia
Chinese Science Bulletin , 2007, DOI: 10.1007/s11434-007-0005-7
Abstract: Using data from previous research on Quercus sect. Heterobalanus, the coexistence approach to Xixabangma and Namling fossil sets, and altitudinal ranges of vegetation presented by fossil floras, a review and reevaluation have been made of existing theories on the uplift of the Himalayas, especially the palaeoaltitudes of Xixabangma and Namling in Tibet. The Xixabangma fossil set has a palaeoaltitude range of 2500–3500 m, and has risen 2200–3400 m since the Pliocene. The lower and upper assemblages of the Miocene Namling had palaeoaltitudes of 2500–3000 m and 2800–3000 m, respectively. Therefore, Namling has risen at least 1300 m since the Miocene, thereby challenging some existing theories that suggest Namling has been static since the Miocene.
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