• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.5
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• pp.707-714
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• 2000

In this paper, using third-order system of the PLL we'll analyze the aspect of flicker noise appearing troubles in the low frequency band. Since it is difficult to analyze mathematically flicker noise in the third-order system of the PLL, introducing the concept of pseudo-damping factor using the optimized second-filter has made an ease of the access of the flicker-noise variance. we'll show a numerical formula of flicker variance in the third-order system of the PLL which is compared with that of 1/f noise variance in the second-order system of the PLL.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 1999.11a
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• pp.230-235
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• 1999

In this paper, Using third-order system of the PLL we analyze the aspect of flicker noise appearing troubles In the low frequency band. Since i. Is difficult to analyze mathematically flirter noise In the third-order system of the PLL, introducing the concept of pseudo-damping factor using the optimized second-filter makes an ease of the access of the flicker-noise variance. we'll show a numerical formula of flicker variance in the third-order system of the PLL which is compared with that of 1/f-noise variance in the second-order system of the PLL.

• Journal of the Korean Society of Costume
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• v.51 no.7
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• pp.123-134
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• 2001

The purpose of this study to compare the purchasing behaviour of men's business suits, among custom suits, system order, and ready-made suits, centering around the choice of information source, risk perception and benefits sought. The survey of this study was collected from 450 adult male in Seoul. The data was analyzed by factor analysis and ANOVA. The result of this study were as follows : 1. Custom suits, system order, and ready-made suits consumers have a significant difference in the choice of information source. The consumer attaching most importance to the impersonal information source is the system order users, custom suits users, and ready-made suits users respectively. However there was no significant difference in the personal source among 3 different purchasing behaviour of men's suits. 2. For the risk perception, 1) the group who perceived the highest in economic risk is the system order users, followed by custom suits users, and ready-made suits users. 2) the group who perceived performance risk as being the highest concern is the ready-made suits consumers, followed by system order user, and custom suits user. 3) the group who perceived the socio-psychological risk as the highest is the ready-made suits consumers, and followed by custom suits user and system order users. 4) there is no difference among the three groups with respect to the fashionability loss risk. 5) the group of the highest perceiving the useful loss risk is the ready-made suits consumers, and the next is system order users, custom suits users. 6) the group of the highest perceiving the time and convenience loss risk is ready-made suits users, and the next is system order users, custom suits users. 3. For the benefit sought, the group of the highest perceiving the aesthetics is custom suits consumers, and the next is system order users, ready-made suits users.

• Proceedings of the Society of Korea Industrial and System Engineering Conference
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• 2002.05a
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• pp.163-170
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• 2002

In the form of B2C transaction, making an on-line order by using the website increases rapidly. An off-line order at the whole sale outlets is geometrically increasing. However, it is so true that both types of market are showing a tendency to become computerization. As to apply this type of computerized B2B transaction to this kind of large scale wholesale outlets, the most important fact to be considered is that there must have no data error. In addition to this, an accurate counting of actual stock is a precondition to decide a suitable amount of production and a timely delivery of goods. In this study, reducing elements of the risk that may create a difference In between actual stock and that in the computer, the integrated B2B ordering system is designed by taking actual cases an example in order to manage the information for a sale, which is conducted by various system in the large scale wholesale outlets such as E-mart, Carefour or the same kinds.

• Journal of KSNVE
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• v.7 no.2
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• pp.223-229
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• 1997

Presented is a method to estimate system parameters of a system with polynomial non-linerities from the measured higher order frequency response functions. Higher order FRFs can be measured on some restricted regions by sinusoidally exciting a non-linear system with various input amplitudes and measuring the response component at the excitation frequency. These higher order FRFs can be expressed in terms of system parameter, and the system parameters can be estimated from the measured FRFs. Since the expressions for higher order FRFs are complicated, system parameters can be estimated from them using an optimization technique. The present method has been applied to a simulated single degree of freedom system with non-linear stiffness and damping, and has estimated accurate system parameters.

• The Journal of Information Systems
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• v.32 no.2
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• pp.1-24
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• 2023

Purpose The aim of this study is to investigate how system quality, privacy concerns, and usefulness impact user satisfaction and word-of-mouth intention towards smart order services among Chinese consumers. The study also seeks to provide both theoretical and practical implications based on the findings. Design/methodology/approach This study conducted an empirical study on Chinese consumers through an online survey on 274 users of smart order service in China. To analyze the data, frequency analysis, reliability analysis, and confirmatory factor analysis were performed using SPSS 26.0 and AMOS 26.0 statistical programs, and structural equation model was used for hypothesis testing. Findings The study results are as follows. First, system quality was found to have a positive effect on usefulness and user satisfaction. Second, privacy concerns were found to have a positive effect on user satisfaction, but not on usefulness. Third, user satisfaction was found to have a positive effect on consumers' word-of-mouth intention of the smart order service. Finally, mediating effects were found between system quality and user satisfaction through usefulness, as well as between system quality, perceived privacy concern, and usefulness through user satisfaction.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.47 no.2
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• pp.190-197
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• 2024

By the recent fast growth of e-commerce markets, it has been stimulated to study order picking systems to improve their efficiency in distribution centers. Many companies and researchers have been developed various types of order picking systems and pursued the corresponding optimal operation policies. However, the performances of the systems with the optimal policies often depend on the structures of the centers and the operation environments. Based on a simulation model that mimics a unique zone picking system operated by a real company in the Republic of Korea, this study compares several operation policies and finds the most appropriate order selection rule and worker assignment policy for the system. Under all scenarios considered in this study, simulation results show that it is recommendable to assign more efficient workers to the zones with heavier workload. It also shows that selecting the order with the maximum number of non-repeatedly visited zones from the order list provides the most consistent and stable performances with respect to flow time, makespan, and utilization of the system even under the scenario with the breakdown zones. On the other hand, selecting the order with the minimum ratio of penalty to the number of zones performs the worst in all scenarios considered.

• Journal of Korean Society of Water and Wastewater
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• v.19 no.4
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• pp.487-496
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• 2005

Chlorine bulk decay tests were carried out by bottle test under controlled conditions in a laboratory. Experiments were performed at different temperatures: $5^{\circ}C$, $15^{\circ}C$, $25^{\circ}C$, and the water temperatures when samples were taken from the effluent just before entering to its distribution system. 38 bulk tests were performed for water of Al (water treatment plant), 4 bulk tests for A2 (large service reservoir), and A3(pumping station). Residual chlorine concentrations in the amber bottles were measured over time till about 100 hours and bulk decay coefficients were evaluated by assuming first-order, parallel first-order, second-order. and $n^{th}-order$ reaction. The $n^{th}-order$ coefficients were obtained using Fourth-order Runge-Kutta Method. A good-fit by the average coefficient of determination ($R^2$) was first-order ($R^2=0.90$) < parallel first-order ($R^2{_{fast}}=0.92$, $R^2{_{slow}}=0.95$) < second-order ($R^2=0.95$) < $n^{th}-order$ ($R^2=0.99$). But if fast reaction of parallel first-order bulk decay were applied to the effluent of large service reservoir with ca. 20 hours of travel time and slow reaction in the water distribution system following the first 20 hours, parallel first-order bulk decay would be best and easy for application of water quality modeling technique.

• Journal of applied mathematics & informatics
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• v.23 no.1_2
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• pp.229-241
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• 2007

Multi-term fractional differential equations have been used to simulate fractional-order control system. It has been demonstrated the necessity of the such controllers for the more efficient control of fractional-order dynamical system. In this paper, the multi-term fractional ordinary differential equations are transferred into equivalent a system of equations. The existence and uniqueness of the new system are proved. A fractional order difference approximation is constructed by a decoupled technique and fractional-order numerical techniques. The consistence, convergence and stability of the numerical approximation are proved. Finally, some numerical results are presented to demonstrate that the numerical approximation is a computationally efficient method. The new method can be applied to solve the fractional-order control system.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.25 no.4
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• pp.173-195
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• 2021

A new implicit discontinuous Galerkin spectral element method (DGSEM) based on the first order hyperbolic system(FOHS) is presented for solving elliptic type partial different equations, such as the Poisson problems. By utilizing the idea of hyperbolic formulation of Nishikawa[1], the original Poisson equation was reformulated in the first-order hyperbolic system. Such hyperbolic system is solved implicitly by the collocation type DGSEM. The steady state solution in pseudo-time, which is the solution of the original Poisson problem, was obtained by the implicit solution of the global linear system. The optimal polynomial orders of 𝒪(𝒽^𝑝+1)) are obtained for both the solution and gradient variables from the test cases in 1D and 2D regular grids. Spectral accuracy of the solution and gradient variables are confirmed from all test cases of using the uniform grids in 2D.