• 자원ㆍ환경경제연구
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• 제15권4호
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• pp.673-692
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• 2006

고갈자원 사용의 동태적 효율성 여부를 검증하기 위해서는 미채굴된 자원의 암묵가격을 추정해야 하는데 기존 연구에서는 자원산업의 한계수입과 한계비용의 차이로 측정하거나 자원채굴량을 준고정시킨 제약비용함수를 추정하여 자원채굴량으로 편미분함으로써 도출하는 방식을 사용하였다. 그러나 이들 방법들은 채굴 투입요소인 자본의 비가단성으로 인하여 일관성이 결여된 추정치가 도출될 개연성, 시장의 독점력에 따라 변하는 한계수입의 가변성 문제와, 불완전한 재화 및 요소시장, 정부규제 등이 존재하는 현실적 상황에서 제약비용함수를 이용할 경우 전제 조건인 생산비용의 최소화가 달성되지 못함으로써 야기될 수 있는 분석결과의 신뢰성 문제 등을 안고 있다. 기존 선행연구의 방법론적 한계점들을 인식하여 본 연구에서는 좀더 일반적이고 현실적 상황에서 고갈자원 사용의 동태적 효율성 여부를 검증할 수 있는 방법을 제시한다. Shephard (1970)의 투입물거리함수를 실증적 모형의 이론적 틀로 활용함으로써 생산요소의 투입량과 최종재화의 산출량에 대한 정보만으로 추정이 가능하고, 생산비용 최소화의 극히 제한적인 상황을 전제하지 않으며, 특히 선형계획기법을 적용함으로써 시계열자료나 합동자료로 회귀 추정할 경우 발생할 수 있는 오차항의 자기상관 문제에 초연할 수 있다. 2%, 5%, 10%, 15%, 20%의 고정 할인율 폭과 실질 이자율의 25%, 50%,100%, 200%, 400%로 산정한 변동할인율을 각각 적용하여 1970년~1993닐 기간 동안 국내 무연탄 채굴의 동태적 효율성 여부를 조사한 결과 고정할인율과 변동할인율 모두에 대해서 국내 무연탄의 세대간 효율적 사용은 이루어지지 않은 것으로 나타났다.

• 간호행정학회지
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• 제6권2호
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• pp.211-225
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• 2000

With the drastically changing healthcare market, the adoption of DRG system and the use of Critical Pathway will be increased gradually in order to care hospitalized patients qualitatively and manage cost-effectively in Korea. The purpose of this quasi-experimental research is to apply and analyze the developed critical pathway to the patients with Cesarean section. 35 eligible subjects for the control group were chosen from postpartum patients who has delivered at H-hospital in Kwang-ju, and were questioned after appling previous care plan from May to December, 1998. For the experimental group, 37 subjects were chosen and questioned after applying Critical Pathway service from January to June, 1999. The instruments are a critical pathway for the patients with Cesarean section developed by chung(1998) and a questionnaire that evaluate patients and family members' satisfaction level. Also, educational materials were used to inform them in the process of Critical Pathway application. As a result of chi-square test on general characteristics, there is significant difference between control group and experimental group only in terms of room size(p= .010). There are no significant differences in the average length of stay in the hospital between control group and experimental group(t=.078). Also, the average medical consult fee has no difference significantly between two groups(t= .105). The findings showed that the experimental group with critical pathway service scored significantly higher than control group on the satisfaction level toward care services(p=.000). The items are post-operative care, postpartum exercise technique, breast feeding and breast manage through educational materials. In conclusion, the research indicates that the application of planned Critical Pathway can have a positive impact on satisfaction level of inpatients with Cesarian section.

• 경영정보학연구
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• 제5권2호
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• pp.1-21
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• 2003

e-비즈니스 환경에서 중개 유통기업은 공급자의 고객과의 직거래에 대한 위협에 대응하여 지속적인 변화를 추구하고 있다. 본 논문에서는 웹 기반 정보기술 활용을 통한 산업재 유통기업의 e-트랜스포메이션 전략을 분석적 관점에서 다루었다. 거래 비용 이론에 의하면 인터넷의 급격한 보급은 중개자와 공급자의 통합 및 아웃소싱에 의한 분할 등 상반되는 두 가지 방향을 동시에 촉진한다고 연구된 바 본 연구에서는 이러한 전략적 변화 방향에 대한 프레임웍을 중개유통 기업의 공급사슬 가치기여 이론과의 결합을 통하여 제시하였다. 공급사슬 가치기여 관점에서는 정보기술과 관련된 공급사슬 특성, 유통채널 조직간의 역학관계, 인터넷 유통 채널 특성 등의 상황적 변수가 포함되었다. 본 논문에서 제시된 프레임웍은 이와 같은 변수들의 복합적인 연계관계가 고려된 상황적 대안을 제시하고 있으며 제안된 명제들의 효과성은 산업재 유통기업의 종단적 심층 사례 연구를 통하여 분석되었다.

• Journal of the Korean Wood Science and Technology
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• 제49권2호
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• pp.122-133
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• 2021

The radon gas from nature mainly considers a cause of radon problems, and it is closely affect human life cycle. Korean yellow residual soil, Hwangtoh, widely used as a building material, is considered to be one of major sources of indoor radon. However, there have, as yet, been no studies about radon from Hwangtoh in mass market brands. Here, we investigated the indoor radon concentrations and exhalation rates in four Hwangtohs from different brand names and regional features. The Closed Chamber Method (CCM) conducted by a Continuous Radon Monitor (CRM) has been used for the rates of radon exhalation. Based on equations of previous references, the indoor radon concentrations were deducted. As a result, the radon surface exhalation rates resulted in the 1.4208 to 3.0293 Bq·㎡·h-1 range. Significant differences were found among Hwangtohs according to production regions. Materials with higher radon concentration required a longer time to reach a quasi-steady state in a given environment, in other words, the number of half-life cycles increased from a set starting point. The experimentally identified Hwangtohs demonstrated its safety for construction purposes. There exists, so far, a possibility to exert influence radon emanation due to unidentified factors. Therefore, it is necessary to corroborate with more research by increasing the number of Hwangtohs, considering the other references reported high radon exhalation rates. In addition, it is highly recommended that the radon exhalation rates should be measured for all building materials for preventing human health before the material usage.

• 한국가금학회지
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• 제20권2호
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• pp.107-114
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• 1993

The structure change in the broiler industry of Korea has been taking place very rapidly toward the direction of integrated production and marketing system. During the course of the evolution into the integrated structure, however, a number of small business entities, uncountable nationally but a minimum of a dozen, that previously engaged in the supply of production factors or live bird transaction also tended to get involved in the new system as a disguised or pseudo-integrator, having brought a lot of problems not only to the farmers but also to the development of integrated structure. The pseudo-integrator is generally characterized by limited functions in such a way of supplying chicks and feeds to and collecting grown birds from farmers under the contract at a fixed farmer's payment in practically the same pattern as a partial or quasi-integration, which intends to act as if an integrator in a stratagem to simply enjoy a margin simply from selling supplies and buying products for a certain period of time. The grower making a contract with appears to be a farmer who used to be an Independent and speculating but not able to join in the normal system of evolving integration. The problems of a pseudo-integrator center on the financial loss to a contract farmer, because the falsified integrator has to become easily bankrupt and run away when the price of live broiler continually stays below the cost of production, even though he is able to make a tremendous profit otherwise which is the real purpose of the operation for. It is true that the volatile market, fluctuating the price up more than doubled in a month and down to a half in a few weeks, makes the pseudo-integrator find the room for such a fraudulence. In addition, its activity also adversely affect the evolution of the integration due to rather negative image on structure change in general. It is recommended that the farmers need to better understand the real picture of the integrated system so as not to be swindled by a disguised, small scale agribusiness agent. By the same token, it is also equally required to have the whole industry integrated completely as early as possible. The Joint effort to get rid of pseudo-integrators' problems shall be put for the industry development moving toward the integration. No doubt a pseudo-integrator must be a temporary player for chance emerging during the course of structure change into the integrated, though.

• 한국데이타베이스학회:학술대회논문집
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• 한국데이타베이스학회 1999년도 춘계공동학술대회: 지식경영과 지식공학
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• pp.175-186
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• 1999

Detecting the features of significant patterns from their own historical data is so much crucial to good performance specially in time-series forecasting. Recently, a new data filtering method (or multi-scale decomposition) such as wavelet analysis is considered more useful for handling the time-series that contain strong quasi-cyclical components than other methods. The reason is that wavelet analysis theoretically makes much better local information according to different time intervals from the filtered data. Wavelets can process information effectively at different scales. This implies inherent support fer multiresolution analysis, which correlates with time series that exhibit self-similar behavior across different time scales. The specific local properties of wavelets can for example be particularly useful to describe signals with sharp spiky, discontinuous or fractal structure in financial markets based on chaos theory and also allows the removal of noise-dependent high frequencies, while conserving the signal bearing high frequency terms of the signal. To date, the existing studies related to wavelet analysis are increasingly being applied to many different fields. In this study, we focus on several wavelet thresholding criteria or techniques to support multi-signal decomposition methods for financial time series forecasting and apply to forecast Korean Won / U.S. Dollar currency market as a case study. One of the most important problems that has to be solved with the application of the filtering is the correct choice of the filter types and the filter parameters. If the threshold is too small or too large then the wavelet shrinkage estimator will tend to overfit or underfit the data. It is often selected arbitrarily or by adopting a certain theoretical or statistical criteria. Recently, new and versatile techniques have been introduced related to that problem. Our study is to analyze thresholding or filtering methods based on wavelet analysis that use multi-signal decomposition algorithms within the neural network architectures specially in complex financial markets. Secondly, through the comparison with different filtering techniques' results we introduce the present different filtering criteria of wavelet analysis to support the neural network learning optimization and analyze the critical issues related to the optimal filter design problems in wavelet analysis. That is, those issues include finding the optimal filter parameter to extract significant input features for the forecasting model. Finally, from existing theory or experimental viewpoint concerning the criteria of wavelets thresholding parameters we propose the design of the optimal wavelet for representing a given signal useful in forecasting models, specially a well known neural network models.

• 한국지능정보시스템학회:학술대회논문집
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• 한국지능정보시스템학회 1999년도 춘계공동학술대회-지식경영과 지식공학
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• pp.175-186
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• 1999

Detecting the features of significant patterns from their own historical data is so much crucial to good performance specially in time-series forecasting. Recently, a new data filtering method (or multi-scale decomposition) such as wavelet analysis is considered more useful for handling the time-series that contain strong quasi-cyclical components than other methods. The reason is that wavelet analysis theoretically makes much better local information according to different time intervals from the filtered data. Wavelets can process information effectively at different scales. This implies inherent support for multiresolution analysis, which correlates with time series that exhibit self-similar behavior across different time scales. The specific local properties of wavelets can for example be particularly useful to describe signals with sharp spiky, discontinuous or fractal structure in financial markets based on chaos theory and also allows the removal of noise-dependent high frequencies, while conserving the signal bearing high frequency terms of the signal. To data, the existing studies related to wavelet analysis are increasingly being applied to many different fields. In this study, we focus on several wavelet thresholding criteria or techniques to support multi-signal decomposition methods for financial time series forecasting and apply to forecast Korean Won / U.S. Dollar currency market as a case study. One of the most important problems that has to be solved with the application of the filtering is the correct choice of the filter types and the filter parameters. If the threshold is too small or too large then the wavelet shrinkage estimator will tend to overfit or underfit the data. It is often selected arbitrarily or by adopting a certain theoretical or statistical criteria. Recently, new and versatile techniques have been introduced related to that problem. Our study is to analyze thresholding or filtering methods based on wavelet analysis that use multi-signal decomposition algorithms within the neural network architectures specially in complex financial markets. Secondly, through the comparison with different filtering techniques results we introduce the present different filtering criteria of wavelet analysis to support the neural network learning optimization and analyze the critical issues related to the optimal filter design problems in wavelet analysis. That is, those issues include finding the optimal filter parameter to extract significant input features for the forecasting model. Finally, from existing theory or experimental viewpoint concerning the criteria of wavelets thresholding parameters we propose the design of the optimal wavelet for representing a given signal useful in forecasting models, specially a well known neural network models.

• 한국위성정보통신학회논문지
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• 제7권3호
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• pp.121-129
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• 2012

현재까지 한국의 자국 우주기반 지역위성항법시스템은 개발되거나 구체적으로 계획되어 있지 않다. 그러나 국내 지역위성항법시스템의 개발요구는 여러 가지 수요 외적인 요인으로도 결정될 수 있으며, 커져가는 국내의 위성항법시스템에 대한 의존도는 결국 자국 위성항법시스템의 개발 및 보유를 궁극적으로 요구할 것으로 사료된다. 한반도 주변을 활용서비스 대상으로 설정하는 지역위성보강항법 시스템 또는 지역위성항법 시스템 둘 다 설계 궤도나 시스템 설계개념은 그리 선택의 여지가 많지 않다. 또한 우주감시 분야는 국내에서 막 태동하는 연구개발 분야이며 미래 한국형항법위성시스템을 보유했을 때 항법시스템의 유지와 항법메세지의 생성을 위해서 반드시 필요한 기술 분야이기도 하다. 이 연구에서는 한국보다 먼저 구축이 기대되는 일본의 준천정위성시스템의 한국 지역 활용도를 분석하고, 유사한 시스템을 한국에 적용했을 때의 활용도 분석, 독자적인 위성항법시스템을 도입했을 때 사용가능한 궤도 얼개 분석, 그리고 이차적인 추적시스템으로서 지상기반 광학추적시스템의 가관측성 등을 분석하였다.

• 한국레이저가공학회:학술대회논문집
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• 한국레이저가공학회 1998년도 추계학술발표대회 초록개요집
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• pp.0-0
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• 1998

-Part I- As market needs become more various, the production of smaller quantities of a wider variety of products becomes increasingly important. In addition, in order to meet demands for more efficient production, long-term unmanned factory operation is prevailing at a remarkable pace. Within this context, laser machines are gaining increasing popularity for use in applications such as cutting and welding metallic and ceramic materials. FANUC supplies four models of $CO_2$ laser oscillators with laser power ranging from 1.5㎾ to 6㎾ on an OEM basis to machine tool builders. However, FANUC has been requested to produce laser oscillators that allow more compact and lower-cost laser machines to be built. To meet such demands, FANUC has developed six models of Slab type YAG laser oscillators with output power ranging from 150W to 2㎾. These oscillators are designed mainly fur cutting and welding sheet metals. The oscillator has an exceptionally superior laser beam quality compared to conventional YAG laser oscillators, thus providing significantly improved machining capability. In addition, the laser beam of the oscillator can be efficiently transmitted through quartz optical fibers, enabling laser machines to be simplified and made more compact. This paper introduces the features of FANUC’s developed Slab type YAG laser oscillators and their applications. - Part II - All-solid-state lasers employing laser diodes (LD) as a source of pumping solid-state laser feature high efficiency, compactness, and high reliability. Thus, they are expected to provide a new generation of processing tools in various fields, especially in automobile and aircraft industries where great hopes are being placed on laser welding technology for steel plates and aluminum materials for which a significant growth in demand is expected. Also, in power plants, it is hoped that reliability and safety will be improved by using the laser welding technology. As in the above, the advent of high-power all-solid-state lasers may not only bring a great technological innovation to existing industry, but also create new industry. This is the background for this project, which has set its sights on the development of high-power, all-solid-state lasers with an average output of over 10㎾, an oscillation efficiency of over 20%, and a laser head volume of below 0.05㎥. FANUC Ltd. is responsible for the research and development of slab type lasers, and TOSHIBA Corp. far rod type lasers. By pumping slab type Nd: YAG crystal and by using quasi-continuous wave (QCW) type LD stacks, FANUC has already obtained an average output power of 1.7㎾, an optical conversion efficiency of 42%, and an electro-optical conversion efficiency of 16%. These conversion efficiencies are the best results the world has ever seen in the field of high-power all-solid-state lasers. TOSHIBA Corp. has also obtained an output power of 1.2㎾, an optical conversion efficiency of 30％, and an electro-optical conversion efficiency of 12%, by pumping the rod type Nd: YAG crystal by continuous wave (CW) type LD stacks. The laser power achieved by TOSHIBA Corp. is also a new world record in the field of rod type all-solid-state lasers. This report provides details of the above results and some information on future development plans.

• 한국결정성장학회지
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• 제29권3호
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• pp.132-139
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• 2019

EPS 단열재는 우수한 단열성능과 경제성, 초경량 등의 장점으로 각광받고 있는 건축재이다. 하지만 EPS 단열재는 가연성 물질로서 화재 시 연소되기 쉽고, 유해가스를 방출시킴으로써 대규모 인명피해를 유발 시킬 수 있다. 따라서 본 논문에서는 산업부산물인 IGCC fused slag 및 Si sludge를 활용하여 초경량 지오폴리머를 제작하고, EPS 단열재의 대체 가능성에 대해 확인하고자 하였다. 그 결과, 조분쇄 상태의 탄소 함량이 적은 IGCC fused slag를 이용하였을 경우 0.04 MPa, $0.064g/cm^3$의 압축강도 및 밀도를 갖는 초경량 지오폴리머를 제작할 수 있었고, 이때의 열전도율은 0.072 W/mK을 나타내었다. 이는 KS M 3808에서 제시하는 EPS 열전도율 값의 1.5~2배 정도의 높은 물성이지만 시중에서 판매하는 EPS 단열재와 큰 차이가 없으며 보통 매립되는 산업 부산물을 재활용한다는 점과 세라믹 재료 특성상 화재시에도 고온에서 버틸 수 있다는 큰 장점이 있기 때문에 화재시 쉽게 발화되어 다량의 유독가스를 방출시키는 EPS 단열재의 단점을 해결할 수 있는 차세대 단열재로서의 가능성은 충분하다고 판단되었다.