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Search Results: 1 - 10 of 127929 matches for " Yang Chen "
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A theory about induced electric current and heating in plasma  [PDF]
Zhiliang Yang, Rong Chen
Natural Science (NS) , 2011, DOI: 10.4236/ns.2011.34035
Abstract: The traditional generalized Ohm’s law in MHD (Magnetohydrodynamics) does not explicitly present the relation of electric currents and electric fields in fully ionized plasma, and leads to some unexpected concepts, such as ``the magnetic frozen-in plasma'', magnetic reconnection etc. In the single fluid model, the action between electric current and magnetic field is not considered. In the two-fluid model, the derivation is based on the two dynamic equations of ions and electrons. The electric current in traditional generalized Ohm's law depends on the velocities of the plasma, which should be decided by the two dynamic equations. However, the plasma velocity, eventually not free, is inappropriately considered as free parameter in the traditional generalized Ohm's law. In the present paper, we solve the balance equation that can give exact solution of the velocities of electrons and ions, and then derive the electric current in fully ionized plasma. In the case ignoring boundary condition, there is no electric current in the plane perpendicular to the magnetic field when external forces are ignored. The electric field in the plane perpendicular to magnetic field do not contribute to the electric currents, so do the induced electric field from the motion of the plasma across magnetic field. The lack of induced electric current will keep magnetic field in space unaffected. The velocity of the bulk velocity of the plasma perpendicular to magnetic field is not free, it is decided by electromagnetic field and the external forces. We conclude that the bulk velocity of the fully ionized plasma is not coupled with the magnetic field. The motion of the plasma do not change the magnetic field in space, but the plasma will be confined by magnetic field. Due to the confinement of magnetic field, the plasma kinetic energy will be transformed into plasma thermal energy by the Lamor motion and collisions between the same species of particles inside plasma. Because the electric field perpendicular to magnetic field do not contribute electric current, the variation of magnetic field will transfer energy directly into the plasma thermal energy by induced electric field. The heating of plasma could be from the kinetic energy and the variation of magnetic field.
Compression of ECG signal using video codec technology-like scheme  [PDF]
Dihu Chen, Sheng Yang
Journal of Biomedical Science and Engineering (JBiSE) , 2008, DOI: 10.4236/jbise.2008.11004
Abstract: In this paper, we present a method using video codec technology to compress ECG signals. This method exploits both intra-beat and inter-beat correlations of the ECG signals to achieve high compression ratios (CR) and a low percent root mean square difference (PRD). Since ECG signals have both intra-beat and inter-beat redundancies like video signals, which have both intra-frame and inter-frame correlation, video codec technology can be used for ECG compression. In order to do this, some pre-process will be needed. The ECG signals should firstly be segmented and normalized to a sequence of beat cycles with the same length, and then these beat cycles can be treated as picture frames and compressed with video codec technology. We have used records from MIT-BIH arrhythmia database to evaluate our algorithm. Results show that, besides compression efficiently, this algorithm has the advantages of resolution adjustable, random access and flexibility for irregular period and QRS false detection.
A Privacy Enabled Fast Dynamic Authentication and Authorization for B3G/4G Mobility  [PDF]
Zhikui CHEN, Song YANG
Communications and Network (CN) , 2009, DOI: 10.4236/cn.2009.12012
Abstract: Mobile technologies make their headway by offering more flexibility to end-users and improve the productivities. Within the application of ubiquitous access and pervasive communication, security (or privacy) and QoS (Quality of Service) are two critical factors during global mobility, so how to get a smooth and fast handover based on a user privacy protected infrastructure is our focus. Based on a user-centric vir-tual identity defined by EU IST project Daidalos, this paper firstly proposes an effective infrastructure which protects the context-driven access policies for online services in order to avoid attacks by malicious eaves-droppers. In the proposed infrastructure, SMAL and Diameter are used to securely protect and deliver au-thenticated and authorized entities and XACML is used to authorize the user-level privacy policy. On the basis of it, a dynamic fast authentication and authorization handover mechanism is proposed which can save one trip communication time consummation between administrative domains.
Study on the Recycling and Treatment of WEEE in China  [PDF]
Bibo Yang, Renxia Chen
American Journal of Operations Research (AJOR) , 2012, DOI: 10.4236/ajor.2012.23033
Abstract: This paper investigates the regulations, recycling and treatment of WEEE (waste electrical and electronic equipment) in China. An online survey about Chinese households’ treatment of WEEE is conducted. Optimization models are used to compare the performances of WEEE treatment in two different recycling networks. In the first network, WEEE is collected and sent by recycling stations to licensed WEEE recycling and treatment centers for testing and dismantling. In the second network, WEEE are tested and dismantled at small recycling workshops in residential districts, and then parts/components that require further processing are sent to licensed WEEE recycling and treatment centers. The performances of the two networks are analyzed with linear programming models. The results indicate that the second model is more effective with lower cost and higher recycling efficiency.
Research on Influence of Manager’s Innovation Preference on Innovation-Decision Making  [PDF]
Chen Tao, Yang Liu
Technology and Investment (TI) , 2012, DOI: 10.4236/ti.2012.33026
Abstract: It is one of the key factors which cause “innovation dilemma” that managers prefer to support the sustaining innovation project. From the view of the manager’s innovation preference, the main propose of the paper is to study why it happened. The manager’s innovation preference will guide and motivate the staffs how to innovate, therefore it is appropriate to analyze it by using the principal agent theory. Conclusions can be got by establishing and analyzing a multi-task principal-agent model. First of all, the model basically explains why incumbent enterprises prefer adopting sustaining innovation and entrant enterprises are inclined to disruptive innovation project. Secondly, the selection rights of middle managers towards innovation projects determine the strategic direction of enterprises. Manager’s innovation preference is consistent with the innovation types of employees. At last, the paper suggests that incumbent enterprises should indeed establish self-organizations or spin-off organizations to better carry out disruptive business.
Investment Value Evaluation of Hi-Tech Industry: Based on Multi-Factor Dynamic Model  [PDF]
Chen Liu, Yang Liu
Open Journal of Business and Management (OJBM) , 2014, DOI: 10.4236/ojbm.2014.23027
Abstract: By constructing a multi-factor dynamic model based on the theory of the lifecycle with China’s A-share data from 2007 to 2013, we analysis the factors affect the investment value and risk of hi-tech industry and their mechanism of action. After the regression, we can draw conclusions: Firstly, hi-tech industries in China are mostly in the growth stage and maturity stage. Investment value of the industries in the growth stage are mostly influenced by market premium factor, market factor, P/E ratio factor and R & D density factor, while hi-tech industries in maturity stage are mainly affected by the market premium factor, market factor, P/E ratio factor. Secondly, dynamic multi-factor model can measure the investment value of hi-tech industries adequately. The conclusions give a reference for investors on how to make investment plan on the stocks of hi-tech enterprises, and provide some policy recommendations on the way promoting hi-tech enterprises to enhance their core technology as well.
Service Cooperation Policy in a Dual-Channel Supply Chain under Service Differentiation  [PDF]
Jun Chen, Ying Yang
American Journal of Industrial and Business Management (AJIBM) , 2014, DOI: 10.4236/ajibm.2014.46036

A service collaboration decision problem in a dual-channel supply chain is studied with the service level and the customer’s acceptance of the Internet channel is taken into consideration. Then the Stackelberg decentralized decision model and the centralized decision model are developed for two settings that the retailer provides the same service level in both channels or not. The conclusion implies that the system profits, the manufacturer’s optimal profit and retailer’s optimal profit are always higher when different services are provided than the same service, and the optimal service level for the direct channel is a little lower than that for the traditional channel under decentralized mode.

Necessary and Sufficient Conditions for a Class Positive Local Martingale  [PDF]
Chuanzhong Chen, Saisai Yang
Advances in Pure Mathematics (APM) , 2014, DOI: 10.4236/apm.2014.410063
Abstract: Let X be a Markov process, which is assumed to be associated with a (non-symmetric) Dirichlet form (E,D(E)) on L2 (E;m). For \"\", the extended Dirichlet space, we give necessary and sufficient conditions for a multiplicative functional to be a positive local martingale.
Deep Cutting Plane Inequalities for Stochastic Non-Preemptive Single Machine Scheduling Problem  [PDF]
Fei Yang, Shengyuan Chen
American Journal of Operations Research (AJOR) , 2015, DOI: 10.4236/ajor.2015.52006
Abstract: We study the classical single machine scheduling problem but with uncertainty. A robust optimization model is presented, and an effective deep cut is derived. Numerical experiments show effectiveness of the derived cut.
The Network Educational Resources Construction on Meteorology Based on Data Mining  [PDF]
Rui Chen, Yang Zhao
Open Journal of Social Sciences (JSS) , 2015, DOI: 10.4236/jss.2015.36001

With the vigorous development of the modern network education technology, the construction of network resource developed towards digital, intelligent and personalized, in order to satisfy the distance learners of different learning needs. By analyzing the problems currently learners in the use of the repository for learning generated by the proposed use of data mining techniques to further planning and construction of the repository, and on how to improve the organizational structure of the repository, and improve the utilization of the repository, personalized to meet the current in-depth research and analysis of learning problems.

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