• Journal of KIISE
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• v.43 no.8
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• pp.835-840
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• 2016

Monte Carlo ray tracing has been widely used for simulating a diverse set of photo-realistic effects. However, this technique typically produces noise when insufficient numbers of samples are used. As the number of samples allocated per pixel is increased, the rendered images converge. However, this approach of generating sufficient numbers of samples, requires prohibitive rendering time. To solve this problem, image filtering can be applied to rendered images, by filtering the noisy image rendered using low sample counts and acquiring smoothed images, instead of naively generating additional rays. In this paper, we proposed a Stein's Unbiased Risk Estimator (SURE) based $\grave{A}$-Trous wavelet to filter the noise in rendered images in a near-interactive rate. Based on SURE, we can estimate filtering errors associated with $\grave{A}$-Trous wavelet, and identify wavelet coefficients reducing filtering errors. Our approach showed improvement, up to 6:1, over the original $\grave{A}$-Trous filter on various regions in the image, while maintaining a minor computational overhead. We have integrated our propsed filtering method with the recent interactive ray tracing system, Embree, and demonstrated its benefits.

• The Journal of the Korea Contents Association
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• v.11 no.1
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• pp.329-339
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• 2011

This study aims at investigating how English proficiency affects economic development of a country by analyzing the relationships among English proficiency, economic activities (amount of trade, R&D investment, etc), and the rate of economic growth, focusing on twenty-one non-English-speaking OECD countries. Ordinary Least Square (OLS) and Seemingly Unrelated Regression Estimation (SURE) were used for the data analysis in the study. The findings reveals that there existed little statistical significance to support the fact that English proficiency was directly related to the economic development in a positive way in many countries except Mexico, the Czech Republic, Finland, and Poland. However, English proficiency indirectly influenced the economic development in the way of increasing the amount of trade. These results can lead to the conclusion that English proficiency is not a sufficient element but a necessary one. Furthermore, it is expected that English proficiency can positively affect the economic development when it plays a part as sufficient complementary goods which make up for physical capital, technology accumulation, political stability, and worthy government.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.11a
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• pp.6-7
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• 2018

In the previous study, durometer, namely rubber hardness tester Was used to confirm the possibility of using the setting time of concrete for determination. in this study, the possibility of using condensation time judgment condensation estimation system by comparing the measuring station setting estimation system Measuring needle of the proctor penetration resistance tester by newly making a measurement needle and refining the coagulation estimation system Want to make sure. As a result of this study, it was possible to use one condensation estimation system showing similar correlation between the two types of durometer showing high correlation with the penetration resistance value of proctor testers, It is considered to be fruitful to use the dew condensation estimation system for determining the setting time.

• Journal of Korean Society of Water and Wastewater
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• v.23 no.2
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• pp.241-249
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• 2009

It is well known that the trend of water demand in large-size water supply systems has been suddenly changed, and many expansions of water supply facilities become unnecessary. To be cost-effective, thus, politicians as well as many professionals lay stress on the adaptive management of water supply facilities. Failure in adapting to the new trend of demand is sure to be the most critical reason of unnecessary expansions. Hence, we try to develop the model and modeling procedure that do not depend on the old data of demand, and provide engineers with the fast learning process. To forecast water demand of Seoul, the Bayesian parameter estimation was applied, which is a representative method for statistical pattern recognition. It results that we can get a useful time-series model after observing water demand during 6 years, although trend of water demand were suddenly changed.

• The Journal of the Korea Contents Association
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• v.10 no.3
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• pp.315-325
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• 2010

The issues on education as a human capital formation in recent years have been focused for all of the countries with emerging of the knowledge-based economy. The present study compared and analyzed the relationships between the educational investment and national economic growth of ten non-English-speaking OECD countries during 1970-2008, using Ordinary Least Square (OLS) and Seemingly Unrelated Regression Estimation (SURE) as the main analytical methods. Findings indicate that educational investment, R&D investment, and fertility rate were statistically significant in the estimation of the variables related to the human capital formation, and these elements had also positive influence on the national economic growth. The most salient factor was the fertility rate, and the R&D investment and educational investment appeared as the next factors in the national economic growth. In particular, the dimensions in the coefficient of the fertility rate showed 1.8 times of the R&D and 3.5 times of the educational investment, respectively. These results imply that educational investment, R&D investment, and the policies which promote fertility rate should be taken into account for the continuous economic growth of each country.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.51 no.1
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• pp.29-36
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• 2002

It is required that the current state of system should be Precisely monitored for efficient and safe operation of the subway power system and it is an important Problem to secure the high quality data for state estimation. The current state of subway power system is estimated by using data transmitted to control center from every measuring instrument. The high accuracy and trust can be maintained if the measured data have a high quality. But it is difficult to estimate the accurate state of system because of the noises in transmitted data and the inaccuracy of measuring instruments. So the object is to reduce the difference between the real values and the measured values in order to improve considerably the inaccuracy due to Instrumental errors and transmission noises using the state estimation method. In this paper, we proposes a new state estimation to estimate the accurate state of the subway power system from the measured values of a Sang-In station in Daegu subway and consider the possibility of application to the real subway power system. on the basis of that. The simulation results show to make sure of the possibility to apply to the real system usefully.

• Asia-Pacific Journal of Business
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• v.2 no.1
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• pp.23-48
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• 2011

Generally, higher brand equity ends up with higher market share and higher profitability. However, superior brand equity does not guarantee the success in the market. That is, consumer choice is closely related to brand equity but we need more than brand equity to explain this complex phenomenon. We adopt the customer equity concepts: value equity, brand equity, and retention equity. By incorporating value equity and retention equity into customer equity, it is possible to avoid the problems of using the brand equity only. In the paper, we apply this customer equity concepts to cellular phone and investigate the effects of antecedent variables such as exposure, knowledge, positive experience and negative experience on the components of customer equity. In addition, as surrogate measure of customer lifetime value, the weighted measure of purchase intention, consideration set inclusion, and next purchase is used as dependent variable. We estimate the effects of components of customer equity at the brand level and aggregate level using SURE model. Estimation results show that Apple has currently low market share but has high future potentials and Korean firms have currently high market share but has rather low future potentials.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1478-1482
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• 2005

Since it is a very issue that figures out a current position of mobile robots, various methods have been proposed until nowadays. This paper proposes the sensor model of RFID(Radio Frequency Identification) and position estimation algorithm for mobile robots. We designed the sensor model of RFID in experimenting repeatedly. The sensor model of RFID in this case is that of stochastics according to sensing rate. Based on this stochastic sensor model, we designed the algorithm which estimates distance and direction of RFID tag. Therefore we made sure that RFID tag is used as landmark.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.1913-1919
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• 2007

Substantive provisions of the concept of an estimation and safety of complex technical systems are envisaged. New problems are assume orientation to use of the formalized methods of an estimation of residual resources of reliability of objects, and also development of other methodological base in creation of complex technical systems that is connected with detailed elaboration of attention to a safety at all stages of creation of systems: from designing until operation. In this connection existing large objects should be provided by the developed systems of engineering monitoring and diagnostics.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.6
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• pp.756-761
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• 2013

This paper propose the new demodulation method that can detect resolver signal's peak at the time of position estimation when the position information is required during current controller period. The proposed method is performed in a synchronous demodulation way with exciting signal and also cover a capability which can compensate the lag element of exciting signal caused by the resolver's inductive component and filter circuit. This paper carried out the experiment to investigate the validity and performance of the suggested method by using the test board made up of DSP and demodulation circuit. The test results show that the proposed method is theoretically clear and work completely as expected from making sure of sampling resolver signal's peak at the time of position estimation. In addition, Software position tracking algorithm is executed with the demodulated signals generated by the suggested method and an exact position can be estimated.