• Journal of the Optical Society of Korea
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• v.10 no.3
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• pp.118-123
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• 2006

We present an optical security method for binary data information by using 4-step phase-shifting digital holography and we analyze tolerance error for the decrypted data. 4-step phase-shifting digital holograms are acquired by moving the PZT mirror with equidistant phase steps of ${\pi}/2$ in the Mach-Zender type interferometer. The digital hologram in this method is a Fourier transform hologram and is quantized with 256 gray level. The decryption performance of the binary data information is analyzed. One of the most important errors is the quantization error in detecting the hologram intensity on CCD. The greater the number of quantization error pixels and the variation of gray level increase, the more the number of error bits increases for decryption. Computer experiments show the results for encryption and decryption with the proposed method and show the graph to analyze the tolerance of the quantization error in the system.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.13 no.3
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• pp.221-230
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• 1988

This paper presents an effective block matching algorithm(BMA) in which the number of search point is about a half of that of three step search, and the number of search step is fixed a four. The performance of the proposed algorithm is compared with those of three step search and one-at-at time search(OTS) for three video sequences composed of 16 framse. Moreover the performance of applying subsampling or integral projection to each BMA for further reducing the amount of computation is considered.

• Journal of the Korean Society of Safety
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• v.32 no.2
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• pp.112-116
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• 2017

Present study investigated the influence of time step size, turbulent eddy viscosity, and the number of layer on rapid and unsteady propagation of dam break flow. When the time step size had a value such that it resulted in Cr of 0.89, a significant numerical oscillation was observed in the vicinity of the wave front. Higher turbulent viscosity ensured smooth and mild slope of velocity and water stage compared with the flow behavior by no viscosity. The vertical velocity at the lower layer positioned near the bottom showed lower velocity compared with other layers.

• Structural Engineering and Mechanics
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• v.29 no.5
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• pp.531-550
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• 2008

This paper adopts the numerical assembly method (NAM) to determine the exact solutions of natural frequencies and mode shapes of a multi-span and multi-step beam carrying a number of various concentrated elements including point masses, rotary inertias, linear springs, rotational springs and springmass systems. First, the coefficient matrix for an intermediate station with various concentrated elements, cross-section change and/or pinned support and the ones for the left-end and right-end supports of a beam are derived. Next, the overall coefficient matrix for the entire beam is obtained using the numerical assembly technique of the conventional finite element method (FEM). Finally, the exact solutions for the natural frequencies of the vibrating system are determined by equating the determinant of the last overall coefficient matrix to zero and the associated mode shapes are obtained by substituting the corresponding values of integration constants into the associated eigenfunctions.

• IE interfaces
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• v.19 no.1
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• pp.86-96
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• 2006

Some customer data of manufacturing industries have a large number of incomplete data set due to the customer's infrequent purchasing behavior and the limitation of customer profile data gathered from sales representatives. So that, most sophisticated data analysis methods may not be applied directly. This paper proposes a heuristic data analysis method to classify customers in household appliances industries. The proposed PD (percent of difference) method can be used for the discriminant analysis of incomplete customer data with simple mathematical calculations. The method is composed of variable distribution estimation step, PD measure and cluster score evaluation steps, variable impact construction step, and segment assignment step. A real example is also presented.

• Nuclear Engineering and Technology
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• v.49 no.5
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• pp.1095-1099
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• 2017

A fission source can act as a stabilization element in coupled Monte Carlo simulations. We have observed this while studying numerical instabilities in nonlinear steady-state simulations performed by a Monte Carlo criticality solver that is coupled to a xenon feedback solver via fixed-point iteration. While fixed-point iteration is known to be numerically unstable for some problems, resulting in large spatial oscillations of the neutron flux distribution, we show that it is possible to stabilize it by reducing the number of Monte Carlo criticality cycles simulated within each iteration step. While global convergence is ensured, development of any possible numerical instability is prevented by not allowing the fission source to converge fully within a single iteration step, which is achieved by setting a small number of criticality cycles per iteration step. Moreover, under these conditions, the fission source may converge even faster than in criticality calculations with no feedback, as we demonstrate in our numerical test simulations.

• Management & Information Systems Review
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• v.1
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• pp.413-443
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• 1997

In today's hospital-management, information system and the information by it will be a necessary administrative materials of organization with man-power, funds, equipment and resources. This study is for figuring out steps to utilize information-system, an important strategy to grow the hospital applying to the change of surroundings, improving the service for patients, accelerating medical examination, improving it in quality and suggesting a basis be able to manage it effectively by putting information system in practice such as economic effect by shorting time and the effect of medical study by computerizing clinical data. And the result of it is as follows: From the Nolan's 6 step - model about the degree using information system in hospital-management, the 1st group of hospital-size came to 1st and 2nd step, the 2nd group to the 3rd and 4th step and the 3rd group to the 5th and 6th step, which correspond to the survey- results that information system increases with the size of the hospital to propagation, regulation and integration step and that the number of the hospital developing to the step managing information is increasing.

• Journal of applied mathematics & informatics
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• v.5 no.3
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• pp.669-690
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• 1998

In this paper we develop a new theory of adjoint and symmetric method in the class of general implicit one-step fixed-stepsize methods. These methods arise from simple and natral def-initions of the concepts of symmetry and adjointness that provide a fruitful basis for analysis. We prove a number of theorems for meth-ods having these properties and show in particular that only the symmetric methods possess a quadratic asymptotic expansion of the global error. In addition we give a very simple test to identify the symmetric methods in practice.

• Proceedings of the Optical Society of Korea Conference
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• 2006.02a
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• pp.335-336
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• 2006

We propose a method of encryption and decryption of binary data using 2-step phase-shifting digital interferometry. This technique reduces the number of interferograms in the phase-shifting interferometry. The binary data has been expressed with random code and random phase. We remove the dc-term of the phase-shifting digital interferogram to restore the original binary data. Simulation results shows that the proposed technique can be used for binary data encryption and decryption.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.38 no.5
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• pp.86-92
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• 2001

The Genetic algorithm is well known as an efficient algorithm which can solve a difficult optimization problems. Recently, there has been increasing interest in applying genetic algorithm to problems related to network design. In this paper, we propose a two step genetic algorithm for designing an optimum virtual path network(VPN) for a given physical network and traffic demand. The first step is to span route between every node pair in the network. The second step assigns VPs to minimize the total number of VPs, the number of VPs carried by a link, and the VPs hopcount. The propose algorithm is evaluated using computer simulation. The result shows that the VPN generated by the proposed algorithm is good in minimizing the number of VPs, the load on a link, and the VPs hopcount.