• Journal of the Korean Geographical Society
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• v.34 no.1
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• pp.99-118
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• 1999

This paper aim to grasp the order region distribution of the goods, which are the sobaeksan ganodenma lucldum on the mail-order through post office and the poum jujube on the mail-order through agncultural Co- operalive and the regional connection made by distributing the goods between production region and sale region The amount of sales for sobaeksan ganodenma lucidum, with little regional difference in the producing volume, is not affected by the basic fare of a long-distance call in the spaual sale. It also shows that the amounl of poun jujude with regional difference of production volume is restricted by distance.

• Journal of the Korea Society of Computer and Information
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• v.12 no.1 s.45
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• pp.25-32
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• 2007

In this paper, the abstract layer for motion capture system is designed and implemented to meet the various hardware and different capturing method. The abstract layer can offer the unified programming by providing device independent API(Application Programming Interface). The device drivers of the optical system and mechanical system are emulated to verify the designed abstract layer. The optical system employs the AOA Ole while the mechanical system uses BVH file. An application program is written to call the abstract layer functions to drive both optical and mechanical drivers and receive the frame data, simulated motion data, that are displayed sequentially on the computer screen by utilizing Direct3D.

• Bulletin of the Korean Mathematical Society
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• v.50 no.6
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• pp.2035-2051
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• 2013

In this paper, we study numerical schemes for solving multi-dimensional option pricing problem. We compare the direct solving method and the Operator Splitting Method(OSM) by using finite difference approximations. By varying parameters of the Black-Scholes equations for the maximum on the call option problem, we observed that there is no significant difference between the two methods on the convergence criterion except a huge difference in computation cost. Therefore, the two methods are compatible in practice and one can improve the time efficiency by combining the OSM with parallel computation technique. We show numerical examples including the Equity-Linked Security(ELS) pricing based on either two assets or three assets by using the OSM with the Monte-Carlo Simulation as the benchmark.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.34S no.11
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• pp.16-24
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• 1997

In order to prevent the presence of the residual phase difference at the discriminator output by the existing AFC techniques, we propose a new automatic frequency control(AFC) tracking algorithm for QPSK demodulation at the digital direct broadcasting satellite(DBS) receiver, which we call a rotational decision-directed AFC(RDDAFC). The RDDAFC rotates the decision boundary for the kth received symbol by the frequency deterctor output of the (k-1)th received symbol. Tracking performances of carrier frequency offset by the proposed RDDAFC algorithm are evaluated through computer simulations under the practical DBS channel conditions with a carrier frequency offset of 2.3MHz when S/N equals 2dB. Test results show that the total pull-in time of the RDDAFC is 1.697msec for 10$^{-3}$ SER before forwared error correction at the receiver.

• The Korean Journal of Applied Statistics
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• v.24 no.4
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• pp.721-733
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• 2011

We consider the state price densities that are implicit in financial asset prices. In the pricing of an option, the state price density is proportional to the second derivative of the option pricing function and this relationship together with no arbitrage principle imposes restrictions on the pricing function such as monotonicity and convexity. Since the state price density is a proper density function and most of the shape constraints are caused by this, we propose to estimate the state price density directly by specifying candidate densities in a flexible nonparametric way and applying methods of regularization under extra constraints. The problem is easy to solve and the resulting state price density estimates satisfy all the restrictions required by economic theory.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.21 no.4
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• pp.45-52
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• 2007

Electric power is an important element in any modern economy. The availability of a reliable power supply at a reasonable cost is important for the economic growth and development of a country. Electric power utilities throughout the world therefore strive to meet customer demands economically with high quality and reliability. As the power industry moves towards open competition, therefore, there has been a call for a methodology by which to evaluate power system reliability through the use of customer interruption characteristics. This paper presents the results of an investigation and analysis of interruption characteristics of an industrial customer in Korea. This study used a direct visit survey to determine the investigation and analysis of electric service quality and the characteristics of industrial customers in Korea. A customer survey conducted throughout Korea via personal interviews of 660 sample customers is presented here. Variation according to characteristics of interruption such as duration, time of day, frequency and day of interruption was also investigated

• Proceedings of the KIEE Conference
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• 1996.07b
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• pp.1301-1303
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• 1996

A new automatic frequency control(AFC) tracking algorithm, which we call a rotational decision directed AFC(RDDAFC) is proposed for QPSK demodulation at the digital direct broadcasting satellite(DBS). In order to prevent the presence of the residual phase difference between symbols received at k and k-l by the CPAFC[1] as well as the AFC based on $tan^{-1}$ circuit[2], the RDDAFC rotates the decision boundary for the kth received symbol by the frequency detector output of the (k-1)th received symbol before passing through the cross product discriminator. Test results show that the total pull-in time of the RDDAFC and PLL was 0.13msec under a carrier frequency offset of 2.4MHz when S/N equals 2dB.

• Journal of Korean society of Dental Hygiene
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• v.13 no.5
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• pp.807-817
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• 2013

Objectives : The aim of the study is to investigate the awareness towards water fluoridation program in the residents of Yongin. Methods : Subjects were 1,016 adults over 19 years old living in Yongin for more than one year. A self-administered survey was done by structured questionnaires. Some of the questionnaires were filled out through direct phone call. Results : Positive awareness of water fluoridation program accounted for 36.5 percent and 61.0 percent of the residents agreed to the program. Only nine percent 9.0 percent opposed to water fluoridation. Conclusions : Yongin City Government is trying to make the residents understand the water fluoridation. Positive public opinion towards the water fluoridation can lead to the implementation of the water fluoridation. So it is necessary to provide information of water fluoridation program to the residents.

• Electronics and Telecommunications Trends
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• v.36 no.4
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• pp.23-33
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• 2021

Wireless communication for train control is an active research field. The World Railway Federation in Europe developed GSM-R, which integrates the GSM-based voice call standard and train control signals. To provide advanced railway services, the LTE-R wireless communication system was developed in Korea for passenger services and wireless image information required by the railroad industry. Recently, direct communication technology for autonomous train driving has been studied to decrease the driving interval, and research is being conducted on a hyperloop train control system that runs at a maximum speed of 1,220km/h in a subvacuum environment of 0.001 atmosphere. In this paper, we summarize the trends in wireless communication technologies used for GSM-R/LTE-R railway systems. For future wireless communication in railway systems, we discuss autonomous train driving and the hyperloop railway control system, define wireless communication technology, and discuss trends in domestic and foreign technologies.

• Structural Engineering and Mechanics
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• v.83 no.2
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• pp.273-282
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• 2022

In this paper, we propose a new concept for error estimation in finite element solutions, which we call mode-based error estimation. The proposed error estimation predicts a posteriori error calculated by the difference between the direct finite element (FE) approximation and the recovered FE approximation. The mode-based FE formulation for the recently developed self-updated finite element is employed to calculate the recovered solution. The formulation is constructed by searching for optimal bending directions for each element, and deep learning is adopted to help find the optimal bending directions. Through various numerical examples using four-node quadrilateral finite elements, we demonstrate the improved predictive capability of the proposed error estimator compared with other competitive methods.