• Journal of the Korean Society for Precision Engineering
• /
• v.17 no.7
• /
• pp.170-180
• /
• 2000

In this paper, to evaluate ease of exchange of subassembly considering module, it needs to analyze structure and function of subassembly, assembly and disassembly process. Exchange process of module can be divided into pre-process and in-process, and determination factors of exchange process are defined by analyzing characteristics of assembly and disassembly process. Based on the analysis of characteristics for structure and function of subassembly, influential factors of module can be proposed. Considered the interrelationship between determination factors of ease of exchange and influencing factors of module, ease of exchange can be evaluated.

• ETRI Journal
• /
• v.36 no.4
• /
• pp.673-681
• /
• 2014

Fairness of exchange is a significant property for secure online transactions, and a fair exchange scheme is a useful tool for ensuring the fairness of exchanges conducted over networks. In this paper, we propose an ID-based optimistic fair exchange scheme based on the RSA function, one which is designed by combining a well-known RSA-based signature scheme and the (naive) RSA function. Note that the main contribution of this paper is to give the first provably secure ID-based fair exchange scheme based on the RSA function, whose security can be proved under fully formalized security models. Our scheme has the following additional strongpoints. The scheme is setup-free; hence, there is no registration step between a user and an arbitrator. Moreover, the proposed scheme is designed in an ID-based setting; thus, it is possible to eliminate the need for certificates and avoid some related problems.

• Journal of applied mathematics & informatics
• /
• v.9 no.2
• /
• pp.745-751
• /
• 2002

In this paper, we Shall find the unique rational price associated with the exchange option. Also, we find the decomposition of Snell envelope and value function of the American exchange option.

• International Commerce and Information Review
• /
• v.10 no.1
• /
• pp.329-347
• /
• 2008

The purpose of this study is to examine the causal relationship between the exchange rate and economic growth, and to induce policy implications. In order to test whether time series data is stationary and the model is fitness or not, we put in operation unit root test, cointegration test. And we apply Granger causality based on an error correction model. The results indicate that uni-dierctional causality between exchange rate and economic growth is detected. Exchange rate impacts on economic growth, but economic growth don't impact on exchange rate. The analysis of impulse reaction function shows that the impulse of exchange rate impacts on Korean economic growth in negative direction. We can infer policy suggestion as follows: The fluctuation of exchange rate much affects economic growth, thus we must make a stable policy of exchange rate to continue economic growth.

• East Asian Economic Review
• /
• v.24 no.1
• /
• pp.61-87
• /
• 2020

Five diffusion models are estimated using three different foreign exchange rates to find an appropriate model for each. Daily spot exchange rates expressed as the prices of 1 euro, 1 British pound and 100 Japanese yen in US dollars, respectively denoted by USD/EUR, USD/GBP, and USD/100JPY, are used. The maximum likelihood estimation method is implemented after deriving an approximate log-transition density function (log-TDF) of the diffusion processes because the true log-TDF is unknown. Of the five models, the most general model is the best fit for the USD/GBP, and USD/100JPY exchange rates, but it is not the case for the case of USD/EUR. Although we could not find any evidence of the mean-reverting property for the USD/EUR exchange rate, the USD/GBP, and USD/100JPY exchange rates show the mean-reversion behavior. Interestingly, the volatility function of the USD/EUR exchange rate is increasing in the exchange rate while the volatility functions of the USD/GBP and USD/100Yen exchange rates have a U-shape. Our results reveal that more care has to be taken when determining a diffusion model for the exchange rate. The results also imply that we may have to use a more general diffusion model than those proposed in the literature when developing economic theories for the behavior of the exchange rate and pricing foreign currency options or derivatives.

• International Journal of Internet, Broadcasting and Communication
• /
• v.12 no.3
• /
• pp.125-130
• /
• 2020

At the end of 1997, the volatility of the exchange rate intensified as the nation's exchange rate system was converted into a free-floating exchange rate system. As a result, managing the exchange rate is becoming a very important task, and the need for forecasting the exchange rate is growing. The exchange rate prediction model using the existing exchange rate prediction method, statistical technique, cannot find a nonlinear pattern of the time series variable, and it is difficult to analyze the time series with the variability cluster phenomenon. And as the number of variables to be analyzed increases, the number of parameters to be estimated increases, and it is not easy to interpret the meaning of the estimated coefficients. Accordingly, the exchange rate prediction model using artificial neural network, rather than statistical technique, is presented. Using DNN, which is the basis of deep learning among artificial neural networks, and LSTM, a recurrent neural network model, the number of hidden layers, neurons, and activation function changes of each model found the optimal exchange rate prediction model. The study found that although there were model differences, LSTM models performed better than DNN models and performed best when the activation function was Tanh.

• Proceedings of the Optical Society of Korea Conference
• /
• 1990.02a
• /
• pp.237-241
• /
• 1990

A detailed theoretical and experimental study of k-na exchange in soda lime silicate glasses by RTP is presented. Concentration profiles i.e. index profiles are given by complementary error function added Gaussian function. The estimated diffusion coefficient is 1.54${\mu}{\textrm}{m}$2/min.

• Journal of the Korean Data and Information Science Society
• /
• v.20 no.4
• /
• pp.655-660
• /
• 2009

As the global economic crisis, the Korean foreign exchange market appears unstable with large fluctuations in exchange rate. Inevitably, there is growing attention on price variables such as exchange rate and interest rates and also on corelation between the factors. This is an empirical study on the causality of fluctuation between exchange rate and interest rate in the Korean market under global economic crisis. The fluctuations in won/dollar exchange rate and call rate are described and followed by analysis of lead-lag relationship between the two variables using Cross-correlation function and Granger causality test.

• Proceedings of the KIEE Conference
• /
• 2007.07a
• /
• pp.402-403
• /
• 2007

전력계통의 효율적인 제어와 운용을 위해서는 전력계통을 구성하는 각종설비의 모델링뿐만 아니라 실시간 시스템 운용 상태에 대한 정확하고 신뢰할 수 있는 정보가 필요하다. 이러한 목적을 위해 현대의 전력계통은 광범위한 데이터를 취득하는 SCADA(Supervisory Control And Data Aquisition)시스템을 기본적으로 갖추고 있다. 본 논문에서는 한국형 에너지관리시스템(Korean Energy Management System)에서의 데이터 취득, 처리, 제공, 제어 등의 기능을 수행하는 SCADA의 요구사항과 설계내용에 관해 소개한다.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.67 no.3
• /
• pp.358-364
• /
• 2018

In this study, the theoretical methodology is presented for estimating cost function based on operating modes for Combined Cycle Power Plant. The proposed method has estimated cost functions using the relationship between the gas turbine heat input and the output ratio of the steam turbine. In order to verify the proposed method, a regression analysis was performed using the single cost function estimated by the existing performance test method and the cost function for each operating mode estimated by the proposed method. The results of case studies using the 2016 generator input and output data are presented to show the effectiveness of the proposed method.