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Search Results: 1 - 10 of 14172 matches for " Minkai Yun "
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Evaluation of imaging protocol for ECT based on CS image reconstruction algorithm
Xiaolin Zhou,Minkai Yun,Xuexiang Cao,Shuangquan Liu,Lu Wang,Xianchao Huang,Long Wei
Physics , 2013, DOI: 10.1088/1674-1137/38/4/048201
Abstract: SPECT (Single-photon Emission Computerized Tomography) and PET (Positron Emission Tomography) are essential medical imaging tools, for which the sampling angle number, scan time should be chosen carefully to compromise between image quality and the radiopharmaceutical dose. In this study, the image quality of different acquisition protocol was evaluated via varied angle number and count number per angle with Monte Carlo simulation data. It was shown that when similar imaging counts were used, the factor of acquisition counts was more important than that of the sampling number in ECT (Emission Computerized Tomography). To further reduce the activity requirement and the scan duration, an iterative image reconstruction algorithm for limited-view and low-dose tomography based on compressed sensing theory has been developed. The total variation regulation was added in the reconstruction process to improve SNR (Signal to Noise Ratio) and reduce the artifacts caused by the limited angle sampling. Maximization of maximum likelihood of the estimated image and the measured data and minimization of the total variation of the image are alternative implemented. By using this advanced algorithm, the reconstruction process is able to achieve image quality matching or exceeding that of normal scan with only half of the injection radiopharmaceutical dose.
G-Contractive Sequential Composite Mapping Theorem in Banach or Probabilistic Banach Space and Application to Prey-Predator System and A & H Stock Prices  [PDF]
Tianquan Yun
Applied Mathematics (AM) , 2011, DOI: 10.4236/am.2011.26092
Abstract: Theorems of iteration g-contractive sequential composite mapping and periodic mapping in Banach or probabilistic Bannach space are proved, which allow some contraction ratios of the sequence of mapping might be larger than or equal to 1, and are more general than the Banach contraction mapping theorem. Application to the proof of existence of solutions of cycling coupled nonlinear differential equations arising from prey-predator system and A&H stock prices are given.
Instant Diffusion Equation of Price Changing and Time-Space Exchanging Description  [PDF]
Tianquan Yun
Technology and Investment (TI) , 2011, DOI: 10.4236/ti.2011.22012
Abstract: Analogy to heat diffusion equation, an instant diffusion equation of price changing is obtained and explained by “time-space exchange” via Newton’s second law, in which the partial derivative of price respected to time is viewed as a “force”, and the derivative of transportation velocity of price between commodities is viewed as an “acceleration”. It is a partial differential equation of second order. The solution of this equation is found and the definitions of “order of commodities”, “distance between commodities” are given. An important relationship of “time-space exchange” in a stationary process of diffusion of price changing is found. This provides a base for describing the relation of “time-space exchange” quantitatively. Examples for calculating and checking the diffusion of price changing in pork, beef, and mutton based on the data taken on February 5th 2008 are given.
Calculation of Changing of Holding Shares or Currencies by Instant Diffusion Equation of Price Changing with Multiple Sources  [PDF]
Tianquan Yun
Modern Economy (ME) , 2012, DOI: 10.4236/me.2012.35068
Abstract: The purpose of this paper is application of the instant diffusion equation to the calculation of strategy on changing of owning shares or currencies. The strategy of selling share(s) with maximum changing rate of price-ratio and purchasing share(s) with minimum changing rate of price-ratio (SMaPMi) is calculated by instant diffusion equation with multiple sources of stock-price changing. The spacial coordinate is defined by stock-price changing ratio at a time before diffu-sion, which ensures that the changing of holding shares using SMaPMi has maximum profit at time next to diffusion ending, based on the comparability of changing rates of stock-price. Summary, SMaPMi would be worked if operation is proper. Calculating example of owning currencies using SMaPMi is given.
The Research on QoS Model Design in Mobile Ad Hoc Networks  [PDF]
Yun Zhang
Int'l J. of Communications, Network and System Sciences (IJCNS) , 2012, DOI: 10.4236/ijcns.2012.511075
Abstract: Wireless Ad Hoc Networks is a special kind of wireless communication network. With the great development of multimedia applications, how to provide QoS guarantee in the MAC layer is the hot topic in wireless ad hoc network (MANET). This paper designed a QoS model in MANET. The feasibility and reliability of this model is analyzed and verified. Compared with the traditional model, the proposed approach is improved in MAC layer in order to achieve high control rate of low-priority transactions.
Fractal and Fractional Diffusion Equations of Price Changing of Commodity  [PDF]
Tianquan Yun
Applied Mathematics (AM) , 2013, DOI: 10.4236/am.2013.47A005

In this paper, three types of modeling of diffusion equations for price changing of commodity are studied. In which, the partial derivatives of price of commodity respected to time on the left hand side are integer-derivative, fractal derivative, and fractional derivative respectively; while just a second order derivative respected to space is considered on the right hand side. The solutions of these diffusion equations are obtained by method of departing variables and initial boundary conditions, by translation of variables, and by translation of operators. The definitions of order of commodity x and the distance between commodity xi and xj are defined as [1]. Examples of calculation of price of pork, beef and mutton mainly due to price raising of pork in 2007-07 to 2008-02 inChina are given with same market data as [1]. Conclusion is made.

On the Operation of CMOS Active-Cascode Gain Stage  [PDF]
Yun Chiu
Journal of Computer and Communications (JCC) , 2013, DOI: 10.4236/jcc.2013.16004

An s-domain analysis of the full dynamics of the pole-zero pair (frequency doublet) associated with the broadly used CMOS active-cascode gain-enhancement technique is presented. Quantitative results show that three scenarios can arise for the settling behavior of a closed-loop active-cascode operational amplifier depending on the relative locations of the unity-gain frequencies of the auxiliary and the main amplifiers. The analysis also reveals that, although theoretically possible, it is practically difficult to achieve an exact pole-zero cancellation. The analytical results presented here provide theoretical guidelines to the design of CMOS operational amplifiers using this technique.

Research on Influencing Factors of Executive Compensation in China’s Monopoly Industries  [PDF]
Yun Dai
Open Journal of Business and Management (OJBM) , 2014, DOI: 10.4236/ojbm.2014.23026
Abstract: The annual salary income of the executives in the state-owned monopoly industry has become the focus of the society recently. With the improvement of enterprise efficiency, executives deserve to get high pay. However, it’s should be noted that because of the state-owned monopolies’ special status, business performance relies heavily on administrative monopoly power, but not actually the efforts of leaders. In this case, the income distribution mechanism is distortion, which has caused great dissatisfaction. This paper aims to study the main affecting factors of the executive compensation of state monopolies, with 1280 firm-year observations of 183 monopoly companies. We find that 1) Executive compensation is positively correlated to firm performance, firm size, CEO duality; 2) Executive compensation is negatively correlated to state share proportion and independent director proportion; 3) Company location, industry both have significant influence on executive compensation.
Application of computer vision technology on raising sow and procreating of processing  [PDF]
Yun Yang
Agricultural Sciences (AS) , 2013, DOI: 10.4236/as.2013.412093

This paper expounds the application of machine vision theory, composition and technology in the sow breeding process monitoring, auxiliary judgment, and growth of young monitoring. It also points out the problems and deficiency in the application of machine vision technology, and discusses the development trends and prospects of the machine vision technology in agricultural engineering. The application of machine vision is a process in which dynamic original image from the sows estrus is collected with a CCD camera, and then black and white ash three binarization image in adjournments of the threshold value is made by using image acquisition card, through the median filtering and gray processing. The practitioners can extract respective image information from the sow estrus, pregnancy and birth delivery. Applying the computer vision system in the sow farm effectively enhances the practitioners’ objectivity and precision in their efforts to assess the whole process of sow birth delivery.

Investment in Hydrogen Engine Must Be Ended with Failure  [PDF]
Tianquan Yun
Journal of Mathematical Finance (JMF) , 2016, DOI: 10.4236/jmf.2016.61008

This paper studies the practicable of hydrogen as a renewable energy source. The study proves a theorem on indirect energy conversion, suggests a monetary unit measured by unit energy, in which, comparing values of different industrial products and comparing different techniques used in production of the same product are better than that of money measured by gold, and proves an assertion, in which, the energy by decomposing a unit water is greater than that by composing a unit water, based on the law of conservation energy. According to the above, we get a conclusion: investment in hydrogen engine must be ended with failure.

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