• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.2
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• pp.407-413
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• 2015

In this paper, a DFPA(decimal floating-point adder) designed a pipeline structure that uses a LZA(leading zero anticipator) to reduce critical route to shorten delay to improve the speed of operation processing. The evaluation and verification of performance of proposed DFPA applied the Flowrian tool with simulation and Cyclone III FPGA was set as the target on the Quartus II tool for the synthesis. The proposed method compared and verified to proposed the other method using same input data. As a result, the performance of proposed method is improved 11.2% and 5.9% more than L.K.Wang's method and etc.. Also, it is confirmed that improvement of operation processing speed and reduction of the number of delay elements on critical path.

• Proceedings of the Korean Information Science Society Conference
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• 2006.10a
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• pp.162-166
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• 2006

선행스케줄링(pre-scheduling)은 정적인 작업(periodic job)과 동적인 작업(sporadic job)을 유연하게 처리하기 위해 제안된 스케줄링 방식이다. 이 방식은 오프라인 컴포넌트와 온라인 컴포넌트로 구성되며 오프라인 컴포넌트에서는 비주기적으로 도착하는 동적인 작업들을 고려하여 정적인 작업들을 여러 부분작업으로 분할하고, 그리고 각 부분작업들의 실행시간, 준비시간, 마감시간을 부여하고 실행순서를 결정한다. 온라인 컴포넌트에서는 이 정보들을 이용하여 정적인 작업들을 정해진 실행순서에 따라 스케줄하고, 동적인 작업이 도착하면 EDF(Earliest Deadline First) 스케줄링 방식으로 처리한다. 그러나 선행스케줄링에서는 자원공유문제를 고려하지 않고 실행시간을 부여하였으므로 여러 정적인 작업들이 하나의 자원을 공유할 경우에 배타적인 자원접근을 보장하지 못한다. 본 논문에서는 단일처리기 환경에서 여러 정적인 작업들의 자원공유를 고려하여 자원의 배타적 사용을 보장하는 선행스케줄 생성기법을 제시한다. 이 기법은 각 작업의 자원 방출시간을 예측하고 예측시간에 근거하여 각 작업의 자원사용구간이 중복되지 않도록 실행시간을 결정한다.

• The Korean Journal of Financial Management
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• v.19 no.2
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• pp.233-251
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• 2002

본 연구는 우리나라를 대상으로 장단기 스프레드와 신용스프레드가 경기변동에 대해 어떠한 예측력을 갖고 있는가를 살펴보았다. 이를 위해 1991년부터 2001년까지를 분석기간으로 하여 Probit 분석을 통해 금리스프레드와 경기변동과의 시차 및 불황확률을 추정하여 평가해 보았으며, 인과관계 검정을 시도해 보았다. 우선 금리스프레드와 경기변동에 대한 불황확률을 알아보기 위해서 Probit 모형을 이용하여 불황확률을 추정하였다. 그 결과 장단기 금리스프레드 중에서는 5년 만기 1종 국민주택채권수익률-콜금리(HCS)는 3개월, 5년 만기 1종 국민주택채권수익률-1년 만기 금융채수익률(HGS)은 7개월, 5년 만기 1종 국민주택채권수익률-1년 만기 통안증권수익률(HMS)은 9개월의 시차를 보이는 경우가 Pseudo $R^2$ 값이 가장 높게 나타났지만 불황확률을 토대로 경기 호황과 불황 국면을 비교해 본 결과 HMS는 Pseudo $R^2$의 값도 상대적으로 높았을 뿐만 아니라 매우 높은 경기변동 예측력을 보여주었다. HCS와 HGS의 경우에는 IMF 체제 전후의 불황기와 그 이후에 도래한 호황기는 예측력이 높게 나타났으나 1990년대 초반에는 제대로 불황확률을 예측하지 못하는 것으로 나타났다. 또한 3년 만기 회사채수익률-5년 만기 국민주택채권수익률(CHS)와 3년 만기회사채수익률 -3년 만기 금융채수익률(CGS)로 나타낸 신용 스프레드에서는 유의적인 결과를 도출하지는 못하였다. 한편 인과관계에서도 HCS, HGS, HMS 등의 장단기 스프레드는 경기변동에 대하여 일방적 원인변수로 작용하는 것으로 나타나 선행결합관계를 보여주었으나 CHS, CGS 등의 신용스프레드는 경기변동과 어떠한 유의적인 결합관계도 보여주지 못하였다. 따라서 장단기 스프레드는 경기변동을 예측하는데 유용한 정보를 제공하지만 신용스프레드는 경기변동을 예측하는데 도움을 주지 못하는 것으로 나타났다.

• Journal of the Korean Institute of Intelligent Systems
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• v.17 no.4
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• pp.563-568
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• 2007

This paper presents a methodology for predicting nonlinear time series based on the neural network with weighted fuzzy membership functions (NEWFM). The degree of classification intensity is obtained by bounded sum of weighted fuzzy membership functions extracted by NEWFM, then weighted average defuzzification is used for predicting nonlinear time series. The experimental results demonstrate that NEWFM has the classification capability of 92.22% against the target class of GDP. The time series created by NEWFM model has a relatively close approximation to the GDP which is a typical business cycle indicator, and has been proved to be a useful indicator which has the turning point forecasting capability of average 12 months in the peak point and average 6 months in the trough point during 5th to 8th cyclical period. In addition, NEWFM measures the efficiency of the economic indexes by the feature selection and enables the users to forecast with reduced numbers of 7 among 10 leading indexes while improving the classification rate from 90% to 92.22%.

• Transactions of the Korean Society of Mechanical Engineers
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• v.14 no.6
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• pp.1436-1445
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• 1990

Performance of vehicles depends mainly on engine performance, transmission gear ration and shifting pattern. In this paper, determination method of gear ratios and shifting pattern for automatic transmission equipped vehicles has been proposed. Computer programs for gear ratio determination and shifting pattern decision using optimal design technique have been developed for the purpose of increasing vehicle acceleration performance. For preceding study, computer simulation of vehicle performance is carried out using numerical technique.

• Journal of the Korean Society of Propulsion Engineers
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• v.16 no.2
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• pp.1-9
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• 2012

Applicability of regenerative cooling in 2,500 N-class bipropellant thruster using hydrogen peroxide and kerosene was considered for improvement of performance and application in various missions. Calculation was performed by one dimensional approach using hydrogen peroxide as a coolant. The heat flux of thruster at nozzle throat was estimated at 18 - 20 MW/$m^2$. Designed cooling channel width and height were 2.5 mm and 0.5 mm, respectively. Based on designed cooling channel configuration, flat plate model was manufactured and tested for estimation of pressure drop in cooling channel, and CFD analysis was compared with the test result. The maximum error between CFD analysis and experimental result was approximately 13% and average error was approximately 5%.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.163-170
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• 2011

Applicability of regenerative cooling in 2,500 N-class bipropellant thruster using hydrogen peroxide and kerosene was considered for improvement performance and application in various missions. Calculation was performed by one dimensional approach using hydrogen peroxide as a coolant. In designed regenerative cooling thruster, heat flux at nozzle throat was estimated at 18 ~ 20 $MW/m^2$. Designed cooling channel width and height were 2.5 mm and 0.5 mm, respectively. Based on designed cooling channel configuration, flat plate model was manufactured and tested for estimation of pressure drop in cooling channel, and CFD analysis was compared with the test result. The maximum error between CFD analysis and experimental result was approximately 13% and average error was approximately 5%.

• Journal of Intelligence and Information Systems
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• v.28 no.3
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• pp.105-117
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• 2022

This study analyzes the effects between stock returns and interest rate spread, difference between long-term and short-term interest rate through the polynomial linear regression analysis. The existing research concentrated on the business forecast through the interest rate spread focusing on the US market. The previous studies verified the interest rate spread based on the leading indicators of business forecast by moderating the period of long-term/short-term interest rates and analyzing the degree of leading. After the 7th reform of composite indices of business indicators in Korea of 2006, the interest rate spread was included in the items of composing the business leading indicators, which is utilized till today. Nevertheless, there are a few research on stock returns of each industry and interest rate spread in domestic stock market. Therefore, this study analyzed the stock returns of each industry and interest rate spread targeting Korean stock market. This study selected the long-term/short-term interest rates with high causality through the regression analysis, and then understood the correlations with each leading period and industry. To overcome the limitation of the simple linear regression analysis, polynomial linear regression analysis is used, which raised explanatory power. As a result, the high causality was verified when using differences between returns of corporate bond(AA-) without guarantee for three years by leading six months and call rate returns as interest rate spread. In addition, analyzing the stock returns of each industry, the relation between the relevant interest rate spread and returns of the automobile industry was the closest. This study is significant in the aspect of verifying the causality of interest rate spread, business forecast, and stock returns in Korea. Even though it could be limited to forecast the stock price by using only the interest rate spread, it would be working as a strong factor when it is properly utilized with other various factors.

• The Journal of the Korea Contents Association
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• v.15 no.7
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• pp.264-281
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• 2015

Suicidal ideation has received much attention from both practitioners and researchers as Korean society becomes aging and individualistic. However, previous researches on the suicide ideation have focused on young generations instead of adults who seem to be more suffered from economic pressure and all kinds of exterior environments causing depression. Besides, there were research voids in the suicidal ideation area where depression was never taken into consideration. In this sense, we attempted to launch empirical studies on analyzing explanatory factors relevant to suicidal ideation in all the age groups by using KNHANES dataset from 2008~2012 years. Especially, we further analyzed KNHANES dataset to know how much depression affects suicidal ideation. Empirical results showed that depression is in a significant relationship with the suicidal ideation in all the demographic dimensions such as age, education, living area, etc.

• Journal of Distribution Research
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• v.10 no.1
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• pp.1-31
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• 2005

In this study, We have newly introduced consumption emotions and switching cost, as a means of managing existing customers, to examine influencing determinants in repurchase intentions along with customer satisfaction and service quality which have been important determinants in previous researches on repurchase intentions. To test them empirically, data from corporate customers of a bank in Korea and corporate banking related bankers are collected and analyzed by LISREL 8.12.. The result of this study can be summed up as follows. First, the most important determinant factor in repurchase intentions is customer satisfaction. Second, it is desirable to measure service quality not only in terms of process service quality, a process of service delivery to customers, but also outcome service quality, what customers receive from services or from service providers. Third, positive consumption emotions have positive influence upon customer satisfaction, negative consumption emotions have negative influence upon customer satisfaction and repurchase intentions. Fourth, switching cost, even though small in its influence, has been proved to be antecedent in repurchase intentions along with customer satisfaction and negative consumption emotions. After research, as precedents in customers' repurchase intentions, customer satisfaction and process service quality have exercised the biggest influences. Also, positive consumption emotions, negative consumption emotions, outcome service quality and switching cost can be used as determinants in predicting corporate customers' repurchase intentions.