• Environmental and Resource Economics Review
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• v.19 no.4
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• pp.733-752
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• 2010

This study applies the Luenberger indicator approach to estimate productivity of the Korean fossil-fueled power plants. A panel data set of 25 power plants was used. The method incorporates $CO_2$ emission as an undesirable output and shows that ignoring $CO_2$ emission overestimates the productivity change. There are two sources of overestimation. First, the usual method estimates productivity change ignoring the increase in $CO_2$ emission that occurred during the study period. Second, the productivity change estimated by the usual method that does not incorporate $CO_2$ emission is very sensitively affected by the change in operation rate. The paper decomposes the productivity change into the efficiency change and the technical change. The results show that the two sources contribute to the productivity change almost equally. It is also shown that the size and the pattern of productivity change are dependent on the plants' fuel types. Non-LNG power plants which saved their energy consumption and thereby reduced their $CO_2$ emission have achieved relatively high rate of productivity improvement.

• KIPS Transactions on Software and Data Engineering
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• v.11 no.3
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• pp.141-148
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• 2022

Recently, reinforcement learning combined with deep neural network technology has achieved remarkable success in various fields such as board games such as Go and chess, computer games such as Atari and StartCraft, and robot object manipulation tasks. However, such deep reinforcement learning describes states, actions, and policies in vector representation. Therefore, the existing deep reinforcement learning has some limitations in generality and interpretability of the learned policy, and it is difficult to effectively incorporate domain knowledge into policy learning. On the other hand, dNL-RRL, a new relational reinforcement learning framework proposed to solve these problems, uses a kind of vector representation for sensor input data and lower-level motion control as in the existing deep reinforcement learning. However, for states, actions, and learned policies, It uses a relational representation with logic predicates and rules. In this paper, we present dNL-RRL-based policy learning for transportation mobile robots in a manufacturing environment. In particular, this study proposes a effective method to utilize the prior domain knowledge of human experts to improve the efficiency of relational reinforcement learning. Through various experiments, we demonstrate the performance improvement of the relational reinforcement learning by using domain knowledge as proposed in this paper.

• KIPS Transactions on Software and Data Engineering
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• v.13 no.1
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• pp.1-16
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• 2024

Over recent years, 6 Sigma has become a key methodology in manufacturing for quality improvement and cost reduction. However, challenges have arisen due to the difficulty in analyzing large-scale data generated by smart factories and its traditional, formal application. To address these limitations, a big data-based 6 Sigma approach has been developed, integrating the strengths of 6 Sigma and big data analysis, including statistical verification, mathematical optimization, interpretability, and machine learning. Despite its potential, the practical impact of this big data-based 6 Sigma on manufacturing processes and management performance has not been adequately verified, leading to its limited reliability and underutilization in practice. This study investigates the efficiency impact of DX SS, a big data-based 6 Sigma, on manufacturing processes, and identifies key success policies for its effective introduction and implementation in enterprises. The study highlights the importance of involving all executives and employees and researching key success policies, as demonstrated by cases where methodology implementation failed due to incorrect policies. This research aims to assist manufacturing companies in achieving successful outcomes by actively adopting and utilizing the methodologies presented.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.11
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• pp.1-9
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• 2016

Train control systems have changed from wayside electricity-centric to onboard communications-centric. The latest train control system, the CBTC system, has high efficiency for interval control based on two-way radio communications between the onboard and wayside systems. However, since the wayside system is the center of control, the number of input trains to allow a wayside system is limited, and due to the cyclic-path control flows between onboard and wayside systems, headway improvement is limited. In this paper, we propose a train interval-control and train-centric distributed interlocking algorithm for an autonomous train-driving control system. Because an autonomous train-driving control system performs interval and branch control onboard, both tracks and switches are shared resources as well as semaphore elements. The proposed autonomous train-driving control performs train interval control via direct communication between trains or between trains and track-side apparatus, instead of relying on control commands from ground control systems. The proposed interlocking algorithm newly defines the semaphore scheme using a unique key for the shared resource, and a switch that is not accessed at the same time by the interlocking system within each train. The simulated results show the proposed autonomous train-driving control system improves interval control performance, and safe train control is possible with a simplified interlocking algorithm by comparing the proposed train-centric distributed interlocking algorithm and various types of interlock logic performed in existing interlocking systems.

• Journal of Embryo Transfer
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• v.9 no.1
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• pp.95-102
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• 1994

본 연구는 종모우의 선발방법으로 난포란을 이용하여 실험실내 정자의 수정능력을 직접 검정하여 평가코자 시도되었다. 즉 본 실험은 후대검정중에 있는 한우 후보종모우 15두의 동결융해정자의 수정능력을 평가하기 위하여 정액을 고장액(HIS)에 처리한 후 DM에서 6시간 그리고 소 난포액이 20% 첨가된 DM에서 4시간 전배양하여 수정능을 획득시켜 정자의 활력과 첨체 반응율을 조사하였고 전배양된 정자의 체내(토끼 난관) 또는 체외수정능력을 조사하기 위하여 FCS 15%, 발정암소혈정(CSS) 10%가 첨가된 mKRB에서 체외성숙된 한우난포란과 수정시켜 수정능력을 평가하였으며 인공수정에 의한 개체별 수태율과도 비교 검토한 바 다음과 같은 결론을 얻었다. 1. 한우 난포란의 체외성숙율은 BSA 첨가구 에서 43.8%, FCS 15% 첨가구에서 67.4%, CSS10% 첨가구에서 69.9%이었다. 2. 토끼 난관에서 체외수정율은 BSA 참가구에서 43.8%, FCS 15% 참가구 41.2% 및 CSS 10% 참가구 35.0% 이었다. 3. 후보종무우 15두의 정액을 HIS-DM으로 처리후 6시간 전배양하였을 때 정자의 활력지수는 9-32%였고 첨체반응율은 19-44% 이었으며 20% 난포액을 첨가하여 4시간 전배양 하였을 때 정자의 활력지수는 9-13% 이었고 첨체반응율은 20-43%로 개체간에 차이가 있었다. 4. 체외수정율은 6.6-85.7%였으며, 발정암소혈청(CSS) 10%가 첨가된 mKRB에서 성숙시킨 난포란이 FCS 15% 첨가된 mKRB에서 성숙시킨 난포란보다 다소 높았으나, 정자수정능획득방법간에는 차이가 없었 다. 5. 체외수정율에 있어서 전배양후 정자활력지수와는 부의 상관이 었으며, 첨체반응율과는 낮은 정의 상 관을 나타냈다. 6. 종모우의 수태율은 체외수정율, 정자활력지수 및 첨체반응율과 낮은 정의 상관관계를 나타냈다. 7. 종모우의 개체간 수태율 우열순위에서는 수정율순위와의 사이에 더욱 낮은 부의 상관관계를 보였다. 8. 이상의 연구결과 비록 후대정검중의 제한된 자료로 인하여 종모우 수태율과 체외수정율간에 유의적 인 상관관계는 없었으나, 연결 한우 수정율 평가에 대한 실험실내의 검정가능성을 찾을 수 있었다.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2002.02a
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• pp.263-268
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• 2002

본 연구는 고추분쇄용 세라믹 롤 분쇄기를 이용하여 고춧가루 생산시, 분쇄효율을 향상시키고자 기존의 롤 분쇄속도 40rpm(0.352m/s)에서 80rpm(0.704%)으로 증가시키고, 기존의 롤 회전비 2:1에서 5:1로 증가시켜 고추분쇄시 전단력 증가로 분쇄능을 향상시켰고, 연구 내용의 주요 결과를 요약하면 다음과 같다. 1. 세라믹치형롤 분쇄속도 40rpm(0.352m/s)에서는 롤 회전비 2:1에서 1,190$\mu\textrm{m}$ 입자가 32.7%, 590$\mu\textrm{m}$ 입자가 19.7%였고, 롤 회전비를 5:1로 증가시 590$\mu\textrm{m}$ 입자가 30.9%, 420$\mu\textrm{m}$ 입자가 17.2%로 중간 미분쇄 영역의 분포가 증가하여 미분쇄 효율이 향상됨을 알 수 있었다. 2. 분쇄물의 롤 통과횟수에 따른 분쇄능은 세라믹치형롤 모두 분쇄속도 80rpm(0.704m/s)에서 분쇄물의 미분쇄능이 향상되었고, 분쇄생성물의 임계처리 횟수가 3~4차임을 분석할 수 있었다. 3. 보통 고춧가루를 생산하는데 분쇄속도 40rpm(0.352m/s), 80rpm(0.704m/s), 두 롤의 회전비 2:1, 3:1, 4:1하에서는 생산되지 않았으나, 롤 회전비 5:1에서는 분쇄속도 40rpm(0.352m/s)일 경우 7차 분쇄후에, 분쇄속도 80rpm(0.704m/s)일 경우 5차분쇄후에 생성되어 분쇄처리횟수가 2회정도 단축되어 전단력 증가로 인하여 분쇄능이 향상된 것으로 분석되었다. 4. 기존의 고춧가루 분쇄조건인 분쇄속도 40rpm(0.352m/s), 롤 회전비 2:1보다 본 연구에서 개발한 분쇄속도 80rpm(0.704m/s), 롤 회전비 5:1인 분쇄조건이, 분쇄처리 횟수 단축 등이 분석됨으로서 섬유질이 많이 포함된 고춧가루 등의 재료가공 분쇄기술이 향상된 것으로 분석되었다.. 마늘재배 일관기계화에 의한 노동투하시간과 비용 -종자준비부터 통마늘선별까지의 일관기계화로 투입된 주요작업의 노력은 75∼76%가 절감되고, 재배규모 3ha기준시 비용은 44-53%절감되었음. the annealing texture. Observations by TEM and EBSD revealed the formation of very fine grains of ∼1.0$\mu\textrm{m}$ after CCSS.he dislocations form local defect arrangements at the grooves permitting the substantial reduction in defect density over the remainder of the interfacial area.한 최대의 감자 재배지역을 형성하였다. 제주도는 산지지형과 따뜻한 기온으로 2기작이 가능하고, 감자가공 공장설립과 교통발달에 따른 육지 시장과의 접근이 용이해졌기 때문에 남한에서 2번째로 큰 감자재배지역이 되었다.(요약 및 결론에서 발췌)그람양성균에서 효과적이었으며, 농도별 항균력시험 결과 농도가 증가할수록 비례하여 저해율도 증가함을 알 수 있었다. 첨가농도를 달리하여 미생물의 생육도를 측정한 결과, fraction II磎꼭\ulcorner경우 그람양성균에 대해 500 ppm 이상에서 뚜렷한 증식억제효과를 나타내었다.서 뚜렷한 증식억제효과를 나타내었다.min/+}$계 수컷 이형접합체 형질전환 마우스에 AIN-76A 정제사료만을 투여한 대조군은 1.40$\pm$0.24(100%)에 비하여 I3C 저농도 투여 실험군(Group 1; 0.85$\pm$0.23; 61%, P<0.01), 그리고 I3C 고농도 투여 실험군(Group 2 ; 1.32$\pm$0.29 ; 94%)의 순으로 감소하였다. 선종의 크기별 종양의 발생개수의

• Journal of Korean Academy of Nursing
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• v.25 no.3
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• pp.581-596
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• 1995

Clinical practice in nursing education provides an opportunity for students, through the process of ap-plying theoretical knowledge to practice, and to learn nursing skills as well as being socialized into nursing and as such decrease the reality shock of actual nursing practice. Because of a shortage of nursing faculty, the job of achieving the objectives of the clinical practice had been turned over to the head nurses. This resulted in many problems, such as, unclear location of responsibilities and inadequate feedback from head nurses. Therefore this study was done to introduce and evaluate the use of preceptors as a way to minimize the above problems, and to maximize the achievement of the clinical practice objectives. Using an adaptation of Zerbe's (1991) three-tiered team model, clinical practice was done using a preceptor, a head nurse and a clinical instructor, each with different and well defined roles. The subjects of this study were 67 senior students of the College of Nursing of Y University in Seoul whose clinical practice in adult nursing was carried out between May 1, 1994 and December 8, 1994. There were 22 preceptors who had at least two years of clinical experience and who were recommended by their head nurses. They were given additional education on the philosophy and objectives of the College of Nursing, on communication skills, on the theory and practice of education, and on nursing diagnosis and education evaluation. The role of the preceptor was to work one-to-one with students in their practice. The role of the head nurse was to supervise and evaluate the preceptors. The role of the clinical instructor was to provide the education program for the preceptors, to provide ad-vice and suggestions to the preceptors and to maintain lines of communication with the college. With each of these roles in place, it was thought that the effectiveness and efficiency of the clinical practice could be increased significantly. To evaluate the effectiveness of the preceptorship, the three - tiered model, Lowery's Teacher Evaluation Opinion Form translated and adapted to Korea was used to measure student statisfaction. The Clinical Practice Compentency Evaluation Tool developed by Lee et ai was also used to measure student competencies. The results of this study are as follows 1. The satisfaction with clinical practice was higher with the introduction of the perceptors than it was before they were used. (t=-5.96, p=<.005) 2. The clinical practice competencies were higher with the introduction of the preceptors than it was before they were used(t=-5.l3, p<.005) 3. In order to analyze areas not measured by the quantitative tools additional analysis of the open questions was done. The results of this analysis showed that : 1) The students felt positive about their sense of security, confidence, handling of responsbility, and being systematic. They also felt positive about improvements in knowledge, opportunities for direct care, and socialization. 2) The students felt negative about the technical part of their role, lack of knowledge by the preceptor, unprofessional attitudes on the part of the preceptor, difficulty in the role of the professional nurse(student). 3) The preceptors felt positive about their responsibility, motivation, and relationship with the college. 4) The preceptors felt negative about their bur-den. Introduction of the preceptorship model will lead to change and improvement in the negative factors discussed above, solve problems in the present clinical education system, increase continuity in the education of the students, help with socialization of the students and motivation of the preceptors to up-grade their education and increase their confidence. These objectives must be obtained to further the development of professional nursing, and thus, making the preceptorship a reality is our job for the future.

• KEPCO Journal on Electric Power and Energy
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• v.3 no.1
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• pp.65-72
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• 2017

This study analyzed causal relationship between electricity consumption and economic output (GDP) for Korea from 2001 to 2014 employing the vector error-correction model estimation by manufacturing sector. The results of unit-roots tests show that all sectoral GDP and electricity consumptions were not stationary. And cointegration tests show that processed foods, Wood Pulp Paper, electricity apparatus, Precision Medical sectors had a linear combinations in the long run between electricity consumptions and economic growth. With respect to the direction of causality, manufacturing sector has a uni-directional running from economic output (GDP) to electricity consumption in short term. The results of study show that sectoral causal relation were different each other in short term and long term. These findings imply that electricity demand management policy focusing on efficiency improvement is necessary to minimize negative impacts on economic growth and to adopt suitable structural policies can induce energy conservation.

• Membrane Journal
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• v.30 no.3
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• pp.173-180
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• 2020

As the demand for fossil fuels continues to increase worldwide, carbon dioxide (CO₂) concentration in the air has increased over the centuries. The way to reduce CO₂ emissions to the atmosphere, carbon capture and sequestration (CCS) technology have been developed that can be applied to power plants and factories, which are primary emission sources. According to the climate change mitigation policy, direct air capture (DAC) in air, referred to as "negative emission" technology, has a low CO₂ concentration of 0.04%, so it is focused on adsorbent research, unlike conventional CCS technology. In the DAC field, chemical adsorbents using CO₂ absorption, solid absorbents, amine-functionalized materials, and ion exchange resins have been studied. Since the absorbent-based technology requires a high-temperature heat treatment process according to the absorbent regeneration, the membrane-based CO₂ capture system has a great potential Membrane-based system is also expected for indoor CO₂ ventilation systems and immediate CO₂ supply to smart farming systems. CO₂ capture efficiency should be improved through efficient process design and material performance improvement.

• Journal of the Korean Institute of Landscape Architecture
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• v.42 no.6
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• pp.101-110
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• 2014

This study analyzes the validity of the type classification of the type and design changes of apartment landscaping planting construction design changes that were completed in the private sector, efficiently manages the design changes that are displayed over landscaping planting work in general in the future, and performs research by placing the object underlying the presentation. The results are as follows. First, the percentage that occurred in the planting construction of design changes that have occurred in the apartment landscaping construction was carried out in the private sector and accounted for 61.8%. This indicates that part of the planting is a major design change. Second, as the cause of such a design change to be those associated with the field conditions such as lack of main construction period. In particular, due to a change in oral, appeared 7-48 times design changes of one review design change approval is complex, design changes of planting construction had shown a feature that occurs in multiple simultaneous. Third, the 7 types of Design Changes in planting design were delineated as 'design changes for consideration of the user', 'design changes for image improvement', 'design changes for ease of maintenance', 'design changes due to the mismatch of design statement', 'design changes due to the relationship with the engineering species of other', 'design changes due to lack of field study', and 'design changes due to the consideration of feasibility.' Fourth, 'design changes for consideration of the user' and 'design changes for image improvement' were found in more than half of the frequency of the overall changes. This differed from the results shown in public corporations. Fifth, if planting construction design change process, private companies, it was found that is showing the approval of the practice after the previous construction of the construction cost savings due to construction time. However, in the case of a public corporation, these exhibited a different aspect from the private sector and show a design change procedure that reflects the changes after the design change events in the field have occurred. The above results, the type of landscaping works in planting design change of public enterprises, regardless of the private sector, is the same in the seven types, the main reason of and procedures for design changes, indicating that there are other respects. In design change, it may be desirable to apply becomes liquidity rationality and efficiency of the dimension, depending on the nature of the landscape construction.