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Search Results: 1 - 10 of 104513 matches for " Yuhong Zhang "
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An Energy-Based Stochastic Model for Wireless Sensor Networks  [PDF]
Yuhong Zhang, Wei Li
Wireless Sensor Network (WSN) , 2011, DOI: 10.4236/wsn.2011.39035
Abstract: We propose an energy-based stochastic model of wireless sensor networks (WSNs) where each sensor node is randomly and alternatively in an active and a sleep mode. We first investigate the sensor model and derive the formula of the steady-state probability when there are a number of data packets in different sensor modes. We then determine important sensor’s performance measures in terms of energy consumptions, average data delay and throughput. The novelty of this paper is in its development of a stochastic model in WSN with active/sleep feature and the explicit results obtained for above mentioned energy consumption and performance characteristics. These results are expected to be useful as the fundamental results in the theoretical analysis and design of various hybrid WSNs with power mode consideration.
A Study on Consumer Behavior of Commercial Health and Fitness Club—A Case of Consumers in Liverpool  [PDF]
Wen Zhang, Yuhong Li
American Journal of Industrial and Business Management (AJIBM) , 2014, DOI: 10.4236/ajibm.2014.41010

Commercial health & fitness clubs are providing an important kind of sporting service. On the basis of questionnaires and interviews with relevant research results, consumers of health & fitness clubs in Liverpool area are studied about their structures including ages, genders, etc., motivation of consumption, and consumption level as well as demand characteristics. Through impressing on the wheel of consumer behavior model, the factors affecting consumer behavior are also analyzed. The most predictable and accessible segments like young adult, affluent, health or appearance conscious consumers are concluded; their lifestyles easily integrate to leisure activities, and time pressure or financial costs are their key concerns. Targeting marketing strategies of the clubs are suggested accordingly in order to design service channel, price reasonably, communicate with consumers and provide satisfying environment.

An Alternate Ring-Ring Design for eRHIC
Yuhong Zhang
Physics , 2015,
Abstract: I present here a new ring-ring design of eRHIC, a polarized electron-ion collider based on RHIC at BNL. This alternate eRHIC design utilizes high repetition rate colliding beams and is likely able to deliver the performance to meet the requirements of the science program with low technical risk and modest accelerator R&D. The expected performance includes high luminosities over multiple collision points and a broad CM energy range with a maximum value up to 2x10^34 cm-2s-1 per detector, and polarization higher than 70% for the colliding electron and light ion beams. This new design calls for reuse of decommissioned facilities in the US, namely, the PEP-II high energy ring and one section of the SLAC warm linac as a full energy electron injector.
Design Concept of a γ-γCollider-Based Higgs Factory Driven by a Thin Laser Target and Energy Recovery Linacs
Yuhong Zhang
Physics , 2012,
Abstract: A {\gamma}-{\gamma} collider has long been considered an option for a Higgs Factory. Such photon colliders usually rely on Compton back-scattering for generating high energy {\gamma} photons and further Higgs bosons through {\gamma}-{\gamma} collisions. The presently existing proposals or design concepts all have chosen a very thick laser target (i.e., high laser photon intensity) for Compton scatterings. In this paper, we present a new design concept of a {\gamma}-{\gamma} collider utilizing a thin laser target (i.e., relatively low photon density), thus leading to a low electron to {\gamma} photon conversion rate. This new concept eliminates most useless and harmful soft {\gamma} photons from multiple Compton scattering so the detector background is improved. It also greatly relaxes the requirement of the high peak power of the laser, a significant technical challenge. A high luminosity for such a {\gamma}-{\gamma} collider can be achieved through an increase of the bunch repetition rate and current of the driven electron beam. Further, a multi-pass recirculating linac could greatly reduce the linac cost and energy recovery is required to reduce the needed RF power.
Pharmacophore Model Generation of Thrombin Inhibitors  [PDF]
Xing Wang, Yanling Zhang, Yuhong Xiang, Zhenzhen Ren, Yanjiang Qiao
Journal of Software Engineering and Applications (JSEA) , 2012, DOI: 10.4236/jsea.2012.512B017
Abstract: Thrombin, an important factor of clotting system, take part in a variety of physiological actions, such as blood clotting, anticoagulation, thrombosis and fibrinolysis. Inhibiting thrombin is a pivotal and effective step for the prophylaxis of venous and arterial thrombosis, as well as prevent myocardial infarction for high-risk patients. In this study, a three dimensional pharmacophore model was generated for the molecules which are responsible for vasodilation activities targeting thrombin. Ten compounds with known thrombin-inhibiting activity values were selected as training set to generate the hypothesis using GALAHAD program in SYBYL 7.0 software. The best hypothesis comprises five pharmacophore features: four hydrophobes groups and one positively charged group. It has been further validated towards a test set including known activity compounds obtained from Binding Database, the values of effectively active hit A% and comprehensive evaluation index CAI are respectively 63.33% and 2.34, the pharmacophore was proven to be successful in discriminating active and inactive inhibitors.  Furthermore, the pharmacophore model was used as a 3D query to screen TCMD (Version 2009) database and 6 hit compounds of higher predicted activity were the reported cardiovascular activities, which may be useful for further study.
Analysis of the Causes and the Consequences of Consecutive RMB Appreciation  [PDF]
Shuixiang Luo, Yue Zhang, Meilin Hu, Yuhong Li
Journal of Financial Risk Management (JFRM) , 2014, DOI: 10.4236/jfrm.2014.31001

Since the reform and opening-up, China’s foreign trade has obtained at breakneck speed, and in the international competition accumulated the massive trade surplus and foreign exchange reserves. That makes some western countries claim that the value of RMB was severely underestimated, which brought about unprecedented and consecutive appreciation pressure of RMB. The appreciation of RMB is highly related to the balance of the internal and external economics. This paper analyzes the background and the impact on Chinese economy of RMB appreciation, and then puts forward some recommendations or strategies accordingly.

Exploring the Impact of Switching Costs on Customer Retention in the Technology Standard Competition Market  [PDF]
Yong Zhang, Xi Chen, Yuhong Zhao, Qiong Yao
Journal of Service Science and Management (JSSM) , 2014, DOI: 10.4236/jssm.2014.74024

As the competition in the market is increasingly fierce, increasing consumers’ switching cost has already become an important strategy for enterprises. However, existing research lacks discussion about switching costs in the standard competition market. This research develops a model of switching costs’ impact on customer retention in the standard competition market. The findings suggest that in the standard competition market, different factors that affect customer switching costs have different effects on switching costs. Technology standard complexity, technology upgradability, and customer investment have significant positive influences on switching costs, but the customer experience presents the negative correlation with switching costs. Furthermore, switching cost is positively related with customer retention, especially the lost benefit cost which has the largest impact on customer retention. This study improves the researches of switching costs antecedent influencing factors, and it is of much importance for enterprises in the standards competition to manage switching costs better and implement customer retention.

Uncertainty Relation for a Quantum Open System
B. L. Hu,Yuhong Zhang
Physics , 1993, DOI: 10.1142/S0217751X95002102
Abstract: We derive the uncertainty relation for a quantum open system comprised of a Brownian particle interacting with a bath of quantum oscillators at finite temperature. We examine how the quantum and thermal fluctuations of the environment contribute to the uncertainty in the canonical variables of the system. We show that upon contact with the bath (assumed ohmic in this paper) the system evolves from a quantum-dominated state to a thermal-dominated state in a time which is the same as the decoherence time in similar models in the discussion of quantum to classical transition. This offers some insight into the physical mechanisms involved in the environment-induced decoherence process. We obtain closed analytic expressions for this generalized uncertainty relation under the conditions of high temperature and weak damping separately. We also consider under these conditions an arbitrarily-squeezed initial state and show how the squeeze parameter enters in the generalized uncertainty relation. Using these results we examine the transition of the system from a quantum pure state to a nonequilibrium quantum statistical state and to an equilibrium quantum statistical state. The three stages are marked by the decoherence time and the relaxation time respectively. With these observations we explicate the physical conditions when the two basic postulates of quantum statistical mechanics become valid. We also comment on the inappropriateness in the usage of the word classicality in many decoherence studies of quantum to classical transition.
Quantum and Thermal Fluctuations, Uncertainty Principle, Decoherence and Classicality*
B. L. Hu,Yuhong Zhang
Physics , 1993,
Abstract: We scrutize the commonly used criteria for classicality and examine their underlying issues. The two major issues we address here are that of decoherence and fluctuations. We borrow the insights gained in the study of the semiclassical limit of quantum cosmology to discuss the three criteria of classicality for a quantum closed system: adiabaticity, correlation and decoherence. We then use the Brownian model as a paradigm of quantum open systems to discuss the relation of quantum and thermal fluctuations and their role in the transition from quantum to classical. We derive the uncertainty relation at finite temperature. We study how the fluctuations of a quantum system evolve after it is brought in contact with a heat bath and analyse the decoherence and relaxation processes. From the effect of fluctuations on decoherence we show the relation between these two sets of criteria of classicality. Finally, we briefly comment on the issue of nonintegrability in quantum open systems.
Uncertainty Relation at Finite Temperature
B. L. Hu,Yuhong Zhang
Physics , 1993, DOI: 10.1142/S0217732393002312
Abstract: We use the quantum Brownian model to derive the uncertainty relation for a quantum open system. We examine how the fluctuations of a quantum system evolve after it is brought in contact with a heat bath at finite temperature. We study the decoherence and relaxation processes and use this example to examine 1) the relation between quantum and thermal fluctuations; and 2) the conditions when the two basic postulates of quantum statistical mechanics become valid.
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