• 품질경영학회지
• /
• 제44권4호
• /
• pp.751-770
• /
• 2016

Purpose: Two-stage ${\bar{X}}$ chart is a useful tool for process control when a surrogate variable may be used together with a performance variable. This paper extends the two-stage ${\bar{X}}$ chart to a three stage version by decomposing the first stage into the preliminary stage and the main stage. Methods: The expected cost function is derived using Markov-chain approach. The optimal designs are found for numerical examples using a genetic algorithm combined with a pattern search algorithm and compared to those of the two-stage ${\bar{X}}$ chart. Sensitivity analysis is performed to see the parameter effects. Results: The proposed design outperforms the optimal design of the two-stage ${\bar{X}}$ chart in terms of the expected cost per unit time unless the correlation between the performance and surrogate variables is modest and the shift in process mean is smallish. Conclusion: Three-stage ${\bar{X}}$ chart may be a useful alternative to the two-stage ${\bar{X}}$ chart especially when the correlation between the performance and surrogate variables is relatively high and the shift in process mean is on the small side.

• 한국실내디자인학회:학술대회논문집
• /
• 한국실내디자인학회 2007년도 추계학술발표대회 논문집
• /
• pp.30-36
• /
• 2007

Recently, many performing arts facilities are under construction to accommodate people's various interest in cultural experiences. However, due to Korea's lack of know-how in such constructions and an absence of proper regulations on design planning, each designer designs and constructs the facilities differently, so several problems are occurring in the process of construction, such as high production cost for stage sets, high labor cost, low efficiency of stage work, and complicated work process. This resulted in low quality production of performance. This study is conducted to address the need for a systematic study on stage floor, and to propose an efficient way of regulating stage work in existing performing arts facilitiesand new facilities to be built. By a comparative analysis of performing arts facilities in Korea, and by analyzing stage floors of the facilities, this research suggests minimum modules as well as an appropriate unit of modules based on the minimum modules; and provides basic data on stage floors, which can be used for remodeling existing facilities orfor planning new cultural facilities. Also, this study suggests various ways of utilizing performing arts facilities in Korea.

• 한국건설관리학회논문집
• /
• 제10권3호
• /
• pp.32-41
• /
• 2009

건설사업관리 업무를 수행하는데 있어 설계이전단계인 사업기획단계, 기본설계 및 실시설계단계가 시공단계보다 중요한 비중을 차지하고 있다. 그러나 건설기술관리법상 건설사업관리 대가 기준으로 본 인력투입기준은 설계이전단계의 중요성을 고려하지 않고 있는 실정이다. 이러한 현실적 상황에 따라 본 연구에서는 건설사업관리 업무의 설계이전단계 인력투입 적정성을 분석하여 개선방안을 제시하는 것을 목적으로 건기법의 용역대가기준과 건설사업관리 용역 4곳의 현장을 비교 분석 하였다. 연구결과 사업수행에 있어 개선된 인력투입의 적정성 분석은 다음과 같이 나타났다. 1)실제 건설사업관리 용역의 단계별 대가평균기준의 인력투입현황을 사업기획단계 신설(6.6%), 기본설계단계(3.9%$\rightarrow$5.6%), 실시설계단계(7.6%$\rightarrow$13.5%), 시공단계(88.5%$\rightarrow$64.0%), 유지관리단계 신설(10.3%)로 제안하였다. 제안된 대가평균기준을 총공사비 기준으로 분류하여 개선후의 요율과 단계별로 산정하여 제시하였다. 2) 건설기술관리법 기준인 3단계기준을 사업기획단계, 유지관리단계를 포함하여 단계별 업무를 구분하여 5단계로 제시하였다. 이와 같은 결과는 건설사업관리 용역현장의 대가 표준 산정이 현실적이고 탄력적으로 운용되고 단계별 인력투입에 대한 제도개선이 현실적으로 이루어져야하는 것으로 볼 수 있다.

• 유체기계공업학회:학술대회논문집
• /
• 유체기계공업학회 2000년도 유체기계 연구개발 발표회 논문집
• /
• pp.312-317
• /
• 2000

High efficient steam turbine stage has been developed with the help of the 3-dimensional design tool. In this stage design, the compound leaned stacking method has been adopted to reduce the secondary flow loss of a turbine passage and to increase the performance efficiency for the turbine nozzles. And the turbine buckets have been designed with the quasi-3-dimensional turbomachinery blade design method. To verify the stage design, therefore, the 3-dimensional numerical simulation of a steam turbine stage was conducted. In this design, CFX-TASCflow was employed to predict the turbulent flow of a steam turbine stage. The analysis was performed in parallel calculation using the HP N4000 8 CPUs machine. The result showed CFX-TASCflow could be used as the 3-dimensional flow analysis tool of steam turbine design.

• 대한기계학회논문집B
• /
• 제24권8호
• /
• pp.1077-1084
• /
• 2000

In this work, a modified stage-stacking method for the performance prediction of multi-stage axial flow compressors is proposed. The method is based on a simultaneous calculation of all interstage variables (temperature, pressure, flow velocity) instead of the conventional sequential stage-by-stage scheme. The method is also very useful in simulating the effect of changing angles of the inlet guide vane and stator vanes on the compressor operating characteristics. Generalized stage performance curves are used in presenting the performance characteristics of each stage. General assumptions enable determination of flow path data and stage design performance. Performance of various real compressors is predicted and comparison between prediction and field data validates the usefulness of the present method.

• 한국정밀공학회지
• /
• 제17권9호
• /
• pp.202-209
• /
• 2000

In recent years the concern of designing multi-stage gear drives increases with the more application of gear drives in high-speed and high-load. until now however research on the gear drive design has been focused on single gear pairs and the design has been depended on experiences and know-how of designers and carried out commonly by trial and error. We propose the automation of the dimensional design of gears and the configuration design for gear arrangement of two-and three-stage cylindrical gear drives. The dimensional design is divided into two types of design processes to determine the dimensions of gears. The first design process(Process I) uses the total volume of gears to determine gear ratio and uses K factor unit load and aspect ratio to determine gear dimensions. The second one(Process II) makes use of Niemann's formula and center distance to calculate gear ratio and dimensions. Process I and II employ material data from AGMA and ISO standards respectively. The configuration design determines the positions of gears to minimize the volume of gearbox by simulated annealing algorithm. Finally the availability of the design algorithm is validated by the design examples of two-and three-stage gear drives.

• 대한조선학회논문집
• /
• 제41권6호
• /
• pp.114-119
• /
• 2004

For passenger vessels, twin shaft types in propulsion system is generally adopted to provide a high-speed performance in low draught due to restricted operating condition in harbors or water channels. Struts of twin open shaft type support the shafts, bearings, and propellers. Therefore, strut design is needed to consider not only hydrodynamic performance but also structural and noise/vibration performance, In this paper, considerations in strut design at the initial design stage have been discussed based on existing references, numerical calculations, and their comparisons. Also, the strut design of a RoPax ferry has been carried out at the initial design stage, for an example.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2002년도 추계학술대회 논문집
• /
• pp.759-762
• /
• 2002

A preliminary design process in the multi-stage gear drives design is important part. a preliminary design support system which run efficiently the design is developed with fuzzy expert system. the system automatically generate the mechanism of multi-stats gear drives and select a candidate mechanism by the general expert rule and sorting using fuzzy expert system. the preliminary mechanism design of multi-stage gear drives have a short execution time, add accuracy in a preliminary design considering volume, cost, power and efficiency in preliminary, a design efficiency is increased and a preliminary design have a elasticity using a weight on variable's sorting mechanism.

• 한국건설관리학회논문집
• /
• 제8권4호
• /
• pp.167-175
• /
• 2007

공동주택 리모델링 프로젝트의 성능개선과정은 일반적으로 프로젝트 의뢰단계, 기획 및 조사진단 단계, 설계단계, 시공단계의 4단계의 사업절차로 구분될 수 있다. 하지만 현재 국내 리모델링 사업은 각 단계별 의사결정 업무체계와 사업수행절차가 체계화 되어있지 못하여 사업수행시 설계자 관점의 종합적 관리계획 수립의 어려움 등 여러 가지 문제점을 겪고 있다. 그 중 리모델링 설계단계는 사업시행자, 설계자, 거주자, 엔지니어 등 사업 참여 주체의 역할 및 업무절차가 타 단계에 비해 매우 복잡하고 정형화되어 있지 못하여 사업에 대한 시행착오, 사업지연, 설계부실 등을 발생시키는 주요 단계로 볼 수 있다. 특히 설계단계에서 각 사업참여자별 발생되는 정보활용 능력에 대한 부족과 부적절한 의사결정으로 인한 설계도서의 부실은 시공단계에 각종 문제를 발생시킬 뿐만 아니라 궁극적으로 거주자가 원하는 리모델링 성능향상에 대한 만족과 신뢰를 어렵게 하고 있다. 따라서 리모델링 설계단계는 매우 주요한 관리대상 단계이며, 설계관리 기술과 함께 사업수행 프로세스에 관한 종합적 이해가 필요하다. 이를 위해 본 연구에서는 리모델링 설계단계를 대상으로 참여사업주체의 역할과 책임을 규정하고, 설계 프로세스 단계별 발생정보를 중심으로 정보활용 과정을 분석하고자 하였다. 본 연구의 정보활용은 발생정보(Input)와 활용기법(Tool) 및 결과물(Output)의 과정으로 분석하였으며, 이를 통해 설계단계별 의사결정 방법을 정립하고, 설계관리 전반의 사업수행 프로세스를 구축하고자 하였다.

• International Journal of Precision Engineering and Manufacturing
• /
• 제2권2호
• /
• pp.57-64
• /
• 2001

In recent years, the concern of designing multi-stage gear drives ha increased with more application of them in high-speed and high-load. Until now, however, the researches on the design of gear drives have been focused on single gear pairs. Thus the design practice for multi-stage gear drives has been depended on experiences and expertise of designers and carried out commonly by trial and error. We propose an automation algorithm for the design of two-and three-strage cylindrical gear drives. The two types of dimensional design processes have been proposed to determine gear dimensions in a formal way. The first design process(Process I) uses to total volume of gears to determine gear ration , and uses K factor , unit load and aspect ration to determine gear dimensions, The second one(Process II) makes use of Niemann's formula and center distance to calculate gear ratio and gear dimensions. Process I and Process II employ material date from AGMA and ISO standards, respectively. The configuration design determines the positions of gears with minimizing the volume of gearbox by using a simulated annealing algorithm. The availability of the design algorithm is validated by the design examples to two-and three=stage gear drives.