• 대한안전경영과학회지
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• 제10권4호
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• pp.47-56
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• 2008

This study suggest a way to improve duty process of KTX(Korea Train Express) high-speed train driver. A new operating system which based on safety was introduced to operate high-speed train which travel above 300km/h on the high-speed railroad but below 200km/h on the general railroad. There were some studies on the operation of high-speed train which travel on the high-speed railroad and on the general railroad with safety. However they overlooked the elements of human errors. The duty-load of KTX train driver's 14 basic operation processes was measured using NASA-TLX and found four processes with high duty-load. In this paper, critical tasks of the high duty-load processes are determined using a questionnaire. Some suggestions which include the improvement of facilities, operating system and operating skill are proposed to lighten duty-load of the critical tasks. The validity of the proposed new task processes is demonstrated by making question to KTX train driver. To use this results cost-benefit analysis, hazards analysis etc. should be performed additionally.

• 대한안전경영과학회지
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• 제24권3호
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• pp.93-103
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• 2022

This study investigated the method of continuous improvement of small-medium company production processes through POSCO's QSS(Quick Six Sigma) activities. QSS is a field operation technique that encompasses the advantages of Six Sigma, TPS(Toyota Production System), TQM (Total Quality Management), and IE(Industrial Engineering). Through this, POSCO not only encourages activities centered on related small and medium-sized partners, etc., but is also expected to contribute to the continuous improvement of the company's own production process through QSS activities. In this study, rather than unconditionally carrying out activities according to the needs of large companies, the research is to help the continuous improvement of the actual production process of small and medium-sized enterprises by effectively applying and spreading QSS activities in consideration of the characteristics and environment of the company. For this purpose, empirical research is conducted on the process improvement activities and QSS activities of company Y, which has less than 100 assembly and production quality and inspection processes among SMEs. The changes in the production process improvement of SMEs through the application of the final QSS were investigated through empirical studies.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 1996년도 제6회 학술강연회논문집
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• pp.197-205
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• 1996

A combined extrusion process studied here consists of forward and backward extrusion, and it is formed in single operation. The metal flow involved in the operation has appeared to be difficult to analyze accurately because of mixed directions of the flow. In this study, conventional two operations of a forward and a backward extrusions is transformed into one operation of mixed extrusion. A process designed by an industry expert is simulated by the rigid-plastic finite element method to investigate the metal flow and defects. In addition to the FEM simulation, experimental analysis has been carried out to confirm the design in industry, which includes material characterization, preliminary expriment, and whole experimental forming operation. The experimental results show that warm forming of extrusion is more desirable than cold working and hot forming in view of grain growth. Also two conditions of lubrication between workpiece and die has been investigated.

• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 1993년도 Proceedings of International Conference for Agricultural Machinery and Process Engineering
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• pp.129-138
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• 1993

The shortage of agricultural labour due to industrial growth has greatly induced the mechanization in Korean agriculture. However small and scattered land holdings have been the main constraints in the process of mechanization. This paper describes the interrelationships of farm land structure, machinery selection and machinery operation areas. The sandy silt loam irrigated paddy land having single crop a year was selected as a target areas for this study. Machine operation cost is greatly influenced by operation period, plot geometry and operation area. On the improved geometry plots, optimal machine size increases slowly with increase in operation area. Operable area increases due to increased effective machine capacity on better geometry plot. The difference between the effects of operation period and plot geometry is that in the former case, the cost reduction is caused by delay in increase of machine size, whereas in the latter case timeliness cost is reduced by increase ffective capacity. The effect of farmland consolidation is greater on small plots than that on big plots. Increasing wage rates have induced the adoption of more labor saving machinery. Bigger labor saving machines require enlargement of operation area and larger plots through improvement in farm land structure. Machine cost on poor plot geometry increases more rapidly than that on the good plot geometry and as operation area increases machine cost reduces significantly. It is concluded that the development of agricultural mechanization ion Korea will depend on the improvement in farm land structure and enlargement of operation area.

• 한국기계가공학회지
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• 제7권2호
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• pp.23-30
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• 2008

As a basic machining process, turning is a widely used machining process in which a single-point cutting tool removes material from the surface of a rotating material. A common method of evaluating machining performance is to measure the surface roughness. In a turning operation, it is important to select cutting conditions for achieving high cutting performance. As a rule, cutting conditions can be classified into feed rate, depth of cut and insert radius. While cutting process even though cutting conditions are optimized, the average roughness can be deterioration due to wear of the cutting tool edge. In this study, the aim is to maintain the average roughness even though the cutting condition is irregularly changing within the predictable range due to the working environment. First, the surface roughness model influenced by cutting conditions is constructed based on the experimental results in a turning operation, Second, applying the sliding mode control theory to the turning operation model which is composed of the surface roughness model and the motor transfer function, the surface roughness is closed to the desired value. Finally, the effectiveness of this approach is demonstrated through the computer simulation.

• 한국가스학회지
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• 제8권4호
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• pp.15-22
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• 2004

본 연구는 LNG 기지 내 주요 프로세스 설비인 LNG 고압펌프의 운전유량 및 토출압력을 조절함으로서 공정운영 조건을 개선하기 위해 수행되었다. 공정 해석 시뮬레이터인 ASPEN PLUS를 사용한 고압펌프의 실제 운전 성능분석 및 천연가스 송출부하 분석을 통하여 계절별 적정 LNG 고압펌프 토출유량을 결정하였고 그 결과는 현장운전에 적용되었다. 이로 인하여 고압펌프 소모 전력비용을 낮출 수 있으며, LNG기지 내 운영 프로세스 압력을 감소 시켜 보다 안전적인 기지운영을 유도할 수 있었다.

• International Journal of Automotive Technology
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• 제8권2호
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• pp.243-248
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• 2007

The durability of a cylinder head is influenced by the thermal and mechanical history during the manufacturing process, as well as engine operation. In order to improve the durability of cylinder head, both load from engine operation and the preload conditions from the manufacturing process must be considered. The aluminum cylinder head used for a HSDI diesel engine is investigated to reduce the possibility of high cycle fatigue crack in this study. FE analysis is performed to elucidate the mechanism of high cycle fatigue crack in the HSDI diesel cylinder head. Two separate approaches to increase the durability of the cylinder head are discussed: reducing load from engine operation and re-arranging preload conditions from the manufacturing process at the critical location of the cylinder head. Local design changes of the cylinder head and modification of pretension load in the cylinder head bolt were investigated using FE analysis to relieve load at the critical location during engine operation. Residual stress formed at the critical location during the manufacturing process is measured and heat treatment parameters are changed to re-arrange the distribution of residual stress. Results of FE analysis and experiments showed that thorough consideration of the manufacturing process is necessary to enhance the durability of the cylinder head.

• 한국CDE학회논문집
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• 제13권3호
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• pp.235-242
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• 2008

This paper proposes a method for improving the process plan quality by use of dimensional tolerances. Dimensioning and tolerancing plays a key role in manufacturing process plan because the final part must ensure conformance with the dimensions and tolerances in its drawing. As a first step for the improvement of process plan quality, two resultant tolerances in design and process plan should be compared each other, and so a tolerance chart is used for acquisition and comparison of the two tolerances. In addition to two kinds of design and manufacturing tolerances, operational sequences or paths for the resultant dimension and tolerance are additionally recognized for measuring the quality of process plan quantitatively. Rooted tree is applied to find the related paths for the manufacturing resultant tolerances. A quality coefficient is defined by the components of two tolerances and their relations, the paths related to manufacturing resultant tolerances and the difficulty of an operation. In order to improve the quality of manufacturing process plan, the paths that two kinds of tolerances are the same or different in the rooted tree are recognized respectively and a method for tolerance rearrangement is developed. A procedure for improving the quality is suggested by combining the coefficient and the tolerance rearrangement method. A case study is applied to illustrate the efficiency of improvement method.

• 한국BIM학회 논문집
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• 제4권2호
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• pp.10-16
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• 2014

Interoperability in the BIM construction information is the information management technology, which allows user to control and effectively use construction's lots of information that occur and disappear through construction life cycle. And it is information interchange through accurate and rapid decision-making to get the participants' wanted value. In this study, we will present plan to improve productivity and quality through effective BIM operation. And we will present improvement plan after deduce existing process's problem.

• 한국콘텐츠학회논문지
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• 제18권9호
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• pp.308-319
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• 2018

본 연구는 R&D 프로젝트 관리 프로세스 개선 및 운영을 위한 평가지표 개발을 위해 연구개발 프로젝트를 수행 하는 국내 중소기업체를 대상으로 실증조사 하였으며, 그 결과를 보면 다음과 같다. 첫째, 12개 평가 지표에 있어 최고 점수인 통합 관리의 60.77점에서부터 최저 점수인 30점대까지 무려 2배 이상의 편차를 보여 R&D 프로젝트 관리 프로세스 및 개선 운영을 위해 선별적 사용이 요구된다. 둘째, 업종별 차이 검정 결과 바이오산업이 가장 높게 나타났으며 화학과 전기전자산업이 가장 낮게 나타났다. 셋째, 종업원 규모별 차이 검정 결과 50~100인 미만이 중소기업에서 상대적으로 높게 나타나고 100인 이상 규모에서는 다소 낮은 차이를 보였다. 넷째, 경력별 차이 검정 결과 5~7년이 상대적으로 높게 나타났으며 7-10년이 다소 높게 나타났다. 전체적으로 R&D 프로젝트 프로세스 개선 운영을 위한 평가 지표 검정 결과 통합관리, 의사소통관리, 리스크관리, 시간관리의 4가지 요인의 순으로 중요도를 나타냈으며, 이는 효율적인 통합관리의 중요성과 각 개별 참여 주체간의 빠른 의사결정과 위험관리에 중심을 두고 집중관리가 요구됨을 시사해주었다.