• 대한지리학회지
• /
• 제34권1호
• /
• pp.99-118
• /
• 1999

산지직송이 많이 이루어지는 비가공 식품인 소백산 영지버섯과 보은 대추의 우체국과 농협을 통한 통신판매지역에 대한 공간구조를 고찰한 결과 다음과 같은 점이 밝혀졌다. 소백산 영지버섯의 지역적 판매는 판매지역의 인구규모에 의해, 보은 대추는 인구규모와 산지와의 시외전화 기본요금에 의해 설명되어 생산량의 지역적 변동이 작고 한약재의 중간재 성격이 강한 영지버섯은 시외전화 기본요금인 거리의 영향을 받지 않는다. 이에 대하여 생산량의 지역적 변동이 크고 최종 소비재의 성격이 강한 보은 대추의 경우는 거리의 제약을 받고 있다는 점이 밝혀졌다.

• 한국컴퓨터정보학회논문지
• /
• 제12권1호
• /
• pp.25-32
• /
• 2007

본 논문은 다양한 모션캡처 하드웨어 장비에 독립적인 응용 프로그램을 작성할 수 있도록 단일화된 추상 레이어를 설계하고 구현하였다. 설계한 추상레이어의 기능을 테스트하고 검증하기 위하여 광학식 모션캡처 시스템과 기계식 모션 캡처 시스템을 각각 AOA 파일과 BVH 파일을 이용하여 에뮬레이션 하였다. 응용 프로그램에서 추상레이어 함수의 호출에 의해 광학식 및 기계식 모션캡처 시스템을 각각 구동하고 시간에 따른 프레임 데이터를 Direct3D를 이용하여 애니메이션 하였다.

• 대한수학회보
• /
• 제50권6호
• /
• pp.2035-2051
• /
• 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.

• 전자공학회논문지S
• /
• 제34S권11호
• /
• pp.16-24
• /
• 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.

• 응용통계연구
• /
• 제24권4호
• /
• pp.721-733
• /
• 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.

• 조명전기설비학회논문지
• /
• 제21권4호
• /
• pp.45-52
• /
• 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

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1996년도 하계학술대회 논문집 B
• /
• pp.1301-1303
• /
• 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.

• 한국치위생학회지
• /
• 제13권5호
• /
• pp.807-817
• /
• 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.

• 전자통신동향분석
• /
• 제36권4호
• /
• pp.23-33
• /
• 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
• /
• 제83권2호
• /
• pp.273-282
• /
• 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.