• 한국멀티미디어학회논문지
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• 제9권10호
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• pp.1296-1303
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• 2006

거리 기반법은 상세한 3D 데이터를 얻기 쉬운 반면 영상 기반법은 그렇지 않다. 본 논문에서는 확대 양안입체 영상으로부터 상세한 3차원 데이터를 얻는 새로운 방법을 제시한다. 주 아이디어는 확대경을 사용하는 것이다. 확대경은 물체를 확대할 뿐만 아니라 깊이 해상도도 증가시킨다. 깊이 해상도 증가와 변위 증폭 사이의 관계를 수학적으로 증명하고 원 3D 데이터를 개선시키는 방법이 제시된다.

• 전기의세계
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• 제28권9호
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• pp.51-59
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• 1979

The forming and design method of D.C thyristor chopper circuit for DC Series motor control is suggested, ard the computation method of thyristor commutaing element's, value which makes it all the more important, is possible. Also the trigger circuit was dealt with. In this paper, in order to control the duty cycle, the duty time is kept on constancy and variable chopping frequency was adopted. By above mentioned circuit design method, the D.C thyristor chopper circuit was implemented and tested. In this circuit, the result of D.C motor control was good and reliable. The relation between the $K_{d}$ and the ratio of input-output current, or the characteristic of speed was varied lineary at the range 0.1 ~ 0.9 of duty cycle. This confirms the fact that D.C to D.C power conversion which is the merit of chopper control is operated most likely a transformer.ormer.

• 국제학술발표논문집
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• The 6th International Conference on Construction Engineering and Project Management
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• pp.392-395
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• 2015

This study analyzes critical factors that affect issues of resolving time in BIM-based coordination using a case study. According to recent buildings that are meant to be more complex, BIM-based design coordination is regarded as an essential stage of the project delivery process. In the design coordination phase, a relocation of architectural, structural, mechanical, and electrical elements is conducted to avoid interference. In addition, the procedure of the development of each element in detail for the actual construction is carried out. Delays in coordination can affect delays in the entire delivery schedule of the project, and therefore many researches have focused on efficient coordination methods and how to shorten the period. In this study, we conducted a detailed analysis of the issue-resolving process using a case study, and found out that the participation of decision-makers for issue-resolving and the physical combination of trades affect delays in coordination time. In particular, we proposed the concept of organizational relation, indicating the level of decision-makers for issue-resolving, and the concept of physical relation, indicating the physical complexity of the issue, and we analyzed the effects of coordination delays.

• 한국수학교육학회지시리즈A:수학교육
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• 제39권2호
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• pp.151-166
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• 2000

The purpose of this study is to understand what two models of SOLO taxonomy and van Hiele theory suggest and find out what relation there is between the category system of the SOLO taxonomy and the thinking level of the van Hiele theory. The van Hiele theory describes in line of ranking level so that it may increase the teaching effects by putting together a class, which takes into consideration the students thoughts. The SOLO taxonomy focused on the response mode of the students rather than the thinking level or the developmental stage of them to pursuit the method that can describe the students understanding in depth quality-wise. Although the SOLO taxonomy and the van Hiele model seem to have different form and character from outside in terms of their goals, a closer examination reveals that the two stances have much in common and that the models are complementary. Although the van Hiele placed more focus on the thoughts, because the conclusion was based on the students responses, the van Hiele theory can be interpreted within the structure identified in the SOLO model. In this study, we have tried to understand how the response structure form the SOLO taxonomy and the thinking level of the van Hiele theory are related, based on the studies of Pegg and Davery1998). If you briefly look at them, there are following corresponding relation between the SOLO taxonomy and the van Hiele theory. a) The relational level(R) in iconic moe is van Hiele level 1. b) The multisturctural level(M$_2$) in the second cycle of concrete-symbolic mode is van Hiel level 2. c) The relation level(R$_2$) in the second cycle of concrete-symbolic mode is van Hiele level 3. d) The unistructural level(U$_2$) in the second cycle of formal mode is van Hiele level 4. e) The postformal mode is van Hiele levle 5. Though it would be difficult to conclude that these correspondences were perfectly done, if you look at their relation, you can see that the learning process of the students were not carried out uniformly. Therefore, by studying the students response structure, using the SOLO taxonomy, and identifying the learning cycle and understand the geometrical concept more in depth.

• 대한인간공학회지
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• 제27권1호
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• pp.1-7
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• 2008

Work related musculoskeletal disorders (WMSDs) have become a hot issue within the Korean workplace for the past several years. Recently, the effect of job related stress on WMSDs, cerebro-cardiovascular diseases, and psychiatric disorders has been steadily increasing. The study conducted questionnaire of Korea version job stress model, WMSDs from NIOSH, CES-D (Center for Epidemiologic Studies Depression Scale), and STAI (State-Trait Anxiety Inventory) against train drivers. The results of this study show that the job stress score of the train drivers is high in the areas of physical environment, job latitude, interpersonal conflict, job insecurity, and organization system. The relation between job stress and WMSDs nd, interpersonal conflict, job insecurity and organizational system. The relation between job stress and depressive disorders showed statistical significance in the areas of job demand, job insecurity and low reward. Finally, the relation between job stress and anxiety disorders showed statistical significance in areas of job demand, interpersonal conflict, job insecurity, organizational system and low reward.

• 디지털산업정보학회논문지
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• 제17권4호
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• pp.161-175
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• 2021

This study analyzed the efficiency and influence factors according to the main research institute type of R&D Program for the local community problem-solving. This study applied data envelopment analysis (DEA) method and Tobit regression analysis by using 20 institutions that participated in R&D Program. The results are summarized as follows. First, Analysis results according to the research institute type of R&D project, Efficient DMUs showed more regional innovation institutions than social economy enterprises. But regional innovation institutions were the lowest in the CCR and BCC model. However, efficiency dose not differ between regional innovation institutions and social economy enterprises. Second, as a result of the analysis relation between efficiency and allocation characteristics of R&D input, the participation of regional innovation organizations as participating organizations has a negative effect on efficiency. It was found that the higher the proportion of government subsidies and the higher the employment rate of the vulnerable, which is a social achievement, the positive effect on efficiency. The implication of this study is that the participation of social economy enterprises as the main R&D institution and government R&D support can provide social economy enterprises with opportunities to accumulate R&D capabilities and experience successful commercialization.

• Journal of Mechanical Science and Technology
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• 제20권12호
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• pp.2147-2158
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• 2006

The continuous wavelet transform (CWT) has a frequency-adaptive time-frequency tiling property, which makes it popular for the analysis of dispersive elastic wave signals. However, because the time-frequency tiling of CWT is not signal-dependent, it still has some limitations in the analysis of elastic waves with spectral components that are dispersed rapidly in time. The objective of this paper is to introduce an advanced time-frequency analysis method, called the dispersion-based continuous wavelet transform (D-CWT) whose time-frequency tiling is adaptively varied according to the dispersion relation of the waves to be analyzed. In the D-CWT method, time-frequency tiling can have frequency-adaptive characteristics like CWT and adaptively rotate in the time-frequency plane depending on the local wave dispersion. Therefore, D-CWT provides higher time-frequency localization than the conventional CWT. In this work, D-CWT method is applied to the analysis of dispersive elastic waves measured in waveguide experiments and an efficient procedure to extract information on the dispersion relation hidden in a wave signal is presented. In addition, the ridge property of the present transform is investigated theoretically to show its effectiveness in analyzing highly time-varying signals. Numerical simulations and experimental results are presented to show the effectiveness of the present method.

• 한국안전학회지
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• 제9권3호
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• pp.22-27
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• 1994

For the $\beta$=1 specimen with constant thickness, Crack growth rate is smoothly increasing in the a-N curve. On the other hand for $\beta$=2 specimen with various thickness, the inflection point is observed in crack growth rate near the thickness interface. da/dN before the inflection point is increased, and da/dN after the point is decreased, compared to the $\beta$=1 specimen. da/dN near the thickness interface is approached zero. The descending point was observed earlier as $\beta$ increased. Considering the relation between da/dN and λ, the crack propagation rates for the case of $\beta$ =1 incrased almost linearly, however, the crack propagation rates for $\beta$=2,3 decreased more rapidly near the thickness interface. Additionally, the decreased point in da/dN for $\beta$=3 is farther from the thickness interface than the case for $\beta$ =2.

• 기술혁신연구
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• 제5권1호
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• pp.181-205
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• 1997

There has been considerable controversy over the impacts of the tax credit on R&D expenditures in many countries. Korea has adopted various kinds of tax credit system to stimulate private firm' R&D expenditures. Korean government, Recently, is trying to reform tax system to reduce tax credit programmes according to Uruguay Round agreement and in line with OECD policy standards. The purpose of this paper is to analyze the effectiveness of current tax credit system on technology innovation in Korea and derive some policy implications over tax reform. In this paper, firstly, I investigate the size of tax reduction effects from each program in theoretical models and simulate the actual rate of individual tax incentive to a unit of R&D expenditure. I find that theoretically the reserve fund for technology development program has given the largest tax reduction effects to private firms irrespective of the R&D incentive system reform. Tax credit on R&D expenditure also has been very effective instrument to firm's tax reduction. Secondly, I try to measure the effectiveness of tax credit through the estimation of effective margianl tax rate between with the system and without the system of credit on R&D expenditure during the tax credit reform periods. I find that the tax credit on R&D has lowered firm's investment cost since the system introduced. I also have strong results that there has been a positive relation between the fluctuation of firm's R&D expenditure and the change of effective marginal tax rate. I suggest that it is better to sustain the system of tax credit on R&D for a while to increase firm's R&D expenditure.

• 한국유기농업학회지
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• 제27권4호
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• pp.391-408
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• 2019

The purpose of this study is to analyze the spillover effect of R & D investment focusing on agriculture sector. Therefore, the Korean industry is divided into 18 industries and the data period including 1970 ~ 2014 is analyzed. In addition, the method is based on the analysis of the production function, the growth contribution of the production factor, and the spillover effect of other industries that affect the agricultural output. The results of this study are summarized as follows. First, R & D investment has a positive effect on the production of Korean agriculture. Second, the impact of high tech industry R & D investment on Korean agriculture is positive. Third, the R & D investment in the public sector is relatively higher than the R & D investment in the private sector. In the R & D stage, the R & D investment of the first level technology has a great influence on the production of agriculture. As a result of this study, governments should consider the above mentioned research results to determine resource priorities based on limited resources in relation to R & D investments that contribute to production and economic growth.