• Journal of Multimedia Information System
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• v.2 no.4
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• pp.311-316
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• 2015

In this paperwork considered problem of using intelligent information systems as an assistant in making decisions by leaders, especially in legal sphere. The lawyers should not judge situation only based on codes or statues, they must take into account other values as well to come to effective solutions to problems. There are a few such programs which could help to make effective and proper decisions.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.35S no.1
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• pp.14-22
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• 1998

The Mathematic model of bit synchronization charge-pump Phase Locked Loop (PLL) is presented which takes into account the aperiodic reference pulses and the leakage current of the loop filter. We derive theoreitcal static phase error, overload and stability of bit synchronization charge-pump PLL using presented model and compare it with one of the conventional charge-pump PLL model. We can analysis bit synchronization charge-pump PLL exactly because our model takes into account the leakage current of the loop filter and aperiodic input data which are the charateristics of bit synchronization charge-pump PLL. We also verify it using HSPICE simulation with a bity synchronizer circuit.

• Bulletin of the Society of Naval Architects of Korea
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• v.11 no.2
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• pp.15-22
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• 1974

As for the added mass moment of inertia of ships in torsional vibration, it seems that the works by T. Kumai[1,2] are the only systematic one available currently. The work[1] is for the calculation of the two dimensional correction factors with finitely-long elliptic cylinders as the mathematic model. In this work the authors recalculated the above factors, $J_{\tau}$, with the same mathematic model and the same problem formulation, and presented the numerical results in Fig. 1. The reason why the reinvestigation was done was that in Kumai's work he obtained the solutions of the Mathieu equations, which was derived from the problem formulation for the velocity potential, under the assumption that the dummy constant q involved in the equations was always far less than unity, whereas in fact it takes values within the region of $0<q{\leq}{\infty}$ in sequence. As a result the authors found two remarkable differences in general features of $J_{\tau}$(refer to Fg.3); one that the authors' numerical results are considerably higher than the results given in [2], and the other that for a given number of node those have properties of decreasing monotonically with increase of the beam-draft ratio while these rapidly decrease from a maximum value of near at B/T=2.00 with B/T becoming greater or less than ratio. It seems that the latter trend was resulted from the fact that the assumption of $q{\ll}1$ employed in [2] was more closely satisfied in the vicinity of B/T=2.00.

• The Mathematical Education
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• v.42 no.5
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• pp.697-706
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• 2003

In this paper we consider the equality sign as a mathematical concept and investigate its meaning, errors made by students, and subject matter knowledge of mathematics teacher in view of The Model of Mathematic al Concept Analysis, arithmetic-algebraic thinking, and some examples. The equality sign = is a symbol most frequently used in school mathematics. But its meanings vary accor ding to situations where it is used, say, objects placed on both sides, and involve not only ordinary meanings but also mathematical ideas. The Model of Mathematical Concept Analysis in school mathematics consists of Ordinary meaning, Mathematical idea, Representation, and their relationships. To understand a mathematical concept means to understand its ordinary meanings, mathematical ideas immanent in it, its various representations, and their relationships. Like other concepts in school mathematics, the equality sign should be also understood and analysed in vie w of a mathematical concept.

• Journal of Power System Engineering
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• v.15 no.4
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• pp.25-30
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• 2011

This study is made to provide with a method for correcting the geometric distortion of the digital radiography image by analytical approach based upon the inverse square law and Beer's law. This study is aimed to find out and improve a mathematic model of nonlinear type. Variations in the alignment of the X-ray source, the object, and imaging plate affect digital radiography images. A model which is expressed in parameter values; e.g, angle, position, absorption coefficient, length, width and pixel account of radiography source, is developed so as to match the sample image. For the best correction of the digital image that is the most similar to the model image, a correction technique based upon tangent is developed; then applied to the digital radiography images of steel tubes. As a result, the image correction is confirmed to be made successfully.

• 제어로봇시스템학회:학술대회논문집
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• 1993.10a
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• pp.576-581
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• 1993

Grinding in the cement industry is a very energy-exacting process, therefore it is essential that these systems should operate with the highest possible efficiency. But, Cement grinding process is a complicated nonlinear system with large dead time, very noisy signal and many stochastic disturbances. So, it is difficult to develope mathematic process model. This paper presents correlation analysis of process variables and construction of experimental model for a ball mill grinding process.

• Journal of Drive and Control
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• v.9 no.4
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• pp.42-51
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• 2012

Variable displacement vane-type oil pumps represent one of the most innovative pump types for industrial applications, especially for engine lubrication systems. This paper deals with a modeling method for theoretical flow rate investigation of a typical variable displacement vane-type oil pump. This theoretical model is based on the pump geometric design and dynamic analyses. It can be considered as mandatory steps for a deeper understanding of the pump operation as well as for effectively implementing the pump control mechanisms to satisfy the urgent demands of engine lubrication systems. The developed pump model is finally illustrated by numerical simulations.

• Geomechanics and Engineering
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• v.11 no.3
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• pp.325-343
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• 2016

A total stress-based bounding surface model is developed to predict the undrained behaviour of saturated soft clays under cyclic loads based on the anisotropic hardening modulus field and bounding-surface theories. A new hardening rule is developed based on a new interpolation function of the hardening modulus that has simple mathematic expression and fewer model parameters. The evolution of hardening modulus field is described in the deviatoric stress space. It is assumed that the stress reverse points are the mapping centre points and the mapping centre moves with the variation of loading and unloading paths to describe the cyclic stress-strain hysteresis curve. In addition, by introducing a model parameter that reflects the accumulation rate and level of shear strain to the interpolation function, the cyclic shakedown and failure behaviour of soil elements with different combinations of initial and cyclic stresses can be captured. The methods to determine the model parameters using cyclic triaxial compression tests are also studied. Finally, the cyclic triaxial extension and torsional shear tests are performed. By comparing the predictions with the test results, the model can be used to describe undrained cyclic stress-strain responses of elements with different stress states for the tested clays.

• Structural Engineering and Mechanics
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• v.35 no.4
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• pp.431-457
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• 2010

This article provides a discussion of the mathematic modeling of connections for designing and qualifying structures, systems, and components subject to monotonic or cyclic loading. To characterize the force-deformation behavior of connections under monotonic loading, a review of the Ramberg-Osgood, Richard-Abbott, and Menegotto-Pinto models is conducted, and it is shown that these nonlinear functions can be mathematically derived by scaling up or down a linear force-deformation function. A generalized four-parameter model for simulating connection behavior is investigated to facilitate nonlinear regression analysis. In order to perform seismic analysis of frameworks, a hysteretic model accounting for loading, unloading, and reloading is described using the established monotonic model. For preliminary analysis, a method is provided to quickly determine the model parameters that fit approximately with the observed data. To reach more accurate values of the parameters, the methods of nonlinear regression analysis are investigated and the modified Levenberg-Marquardt and separable nonlinear least-square algorithms are applied in determining the model parameters. Example case studies illustrate the procedure for the computation through the use of experimental/analytical data taken form the literature. Transformation of connection curves from the three-parameter model to the four-parameter model for structural analysis is conducted based on the modeling of connections subject to fire.

• Journal of international Conference on Electrical Machines and Systems
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• v.3 no.2
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• pp.215-221
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• 2014

To satisfy the high voltage direct current (HVDC) grid connection demand for wind power generation system, a novel topology and control strategy of HVDC grid connection for open-winding permanent magnet synchronous generator (PMSG) based wind power generation system is proposed, in which two generator-side converter and two isolated DC/DC converters are used to transmit the wind energy captured by open winding PMSG to HVDC grid. By deducing the mathematic model of open winding PMSG, the vector control technique, position sensorless operation, and space vector modulation strategy is applied to implement the stable generation operation of PMSG. Finally, the simulation model based on MATLAB is built to validate the availability of the proposed control strategy.