• Journal of Korean Society for Quality Management
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• v.44 no.4
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• pp.751-770
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• 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.

• Journal of the Korean Operations Research and Management Science Society
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• v.26 no.4
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• pp.1-21
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• 2001

The purpose of this stuffy is to derive critical success factors for ERP system implementation by integrating managerial, technical. human resource and organizational culture factors welch have been proposed as influencing factors for the performance of ERP system implementation in previous studios. Especially, this stuffy divides ERP system implementation process into preparation stave, implement stage and settle-down and stabilization stave, and then derives critical success factors in each stage. The data for empirical analysis of the research model are collected from 64 companies and the respondents for questionnaire consist of ERP system implementation project managers and user department managers in companies which have already operated it after ERP system installation. The main results of this study are as follows. First, it derives 27 success factors through comprehensive review of various factors which may affect ERP system implementation performance, and categorizes them into one of three stapes preparation stave, implement stage, and settle-down and stabilization stage. Second, the relationship between many success factors at each stave (preparation stave, implement stage, and settle-down and stabilization stave) and performance variables is tested. As a result, the significant correlations between many success factors at each stage and ERP system implementation performance are found, and the difference among success factors in the degree of influencing the system performance is significantly shown. finally, the relationship between process-oriented performance variables and result-oriented performance ones is tested. As a result, it is found that there is significant correlation between process-oriented performance variables except for one variable-project resource management appropriateness - and result-oriented performance ones. The theoretical contribution of this study is to derive a comprehensive model of critical success factors for implementing ERP system project from the system deve1opment life cycle perspective, and empirically test it through field survey with a wide range of data collection. And, the practical implication of this study is to present the desirable guidelines for performing ERP system implementation project successfully.

• Nuclear Engineering and Technology
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• v.55 no.7
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• pp.2697-2711
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• 2023

In this study, the validity of reducing the number of gas turbine stages designed for a nitrogen Brayton cycle coupled to a sodium-cooled fast reactor was assessed. The turbine performance was evaluated through computational fluid dynamics (CFD) simulations under different off-design conditions controlled by a reduced flow rate and reduced rotational speed. Two different multistage gas turbines designed to extract almost the same specific work were selected: two- and three-stage turbines (mid-span stage loading coefficient: 1.23 and 1.0, respectively). Real gas properties were considered in the CFD simulation in accordance with the Peng-Robinson's equation of state. According to the CFD results, the off-design performance of the two-stage turbine is comparable to that of the three-stage turbine. Moreover, compared to the three-stage turbine, the two-stage turbine generates less entropy across the shock wave. The results indicate that under both design and off-design conditions, increasing the stage loading coefficient for a fewer number of turbine stages is effective in terms of performance and size. Furthermore, the Ellipse law can be used to assess off-design performance and increasing exponent of the expansion ratio term better predicts the off-design performance with a few stages (two or three).

• Journal of Korean Society of Industrial and Systems Engineering
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• v.41 no.2
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• pp.65-73
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• 2018

The dynamic capabilities of sensing market signals, creating new opportunities and reconfiguring resources and capabilities to new opportunities in a rapidly changing economic environment determines the competitiveness of the enterprise to create added value and survival. This study conceptualized a two-stage performance measurement framework based on the casual model of resource (input)-process-performance (output). We have developed a 'Process capability index' that reflect the dynamic capabilities factors as a key intermediary product linking resource inputs and performance outputs in enterprise performance measurement. The process capability index consists of four elements : manpower (level of human resource), operation productivity, structure and risk management. The DEA (Data Envelopment Analysis) model was applied to the developed performance indicators to analyze the branch office performance of a telecom company. Process capability efficiency (stage 1) uses resource inputs to reach a certain level of process capabilities. In performance result efficiency (stage 2), the process capabilities are used to generate sales revenues and subscribers. The two-stage DEA model derives intermediate output values that optimize the individual stages simultaneously. Some branch offices in the telecom company have focused on process capability efficiency or some other branch offices focused on performance result efficiency. Positioning map using two-stage efficiency decomposition and benchmarking can help identify the sources of inefficiencies and visualize strategic directions for performance optimization. Applications of two-stage DEA in conjunction with the case study that are meaningfully used in performance measurement areas have been scarce. In particular, this paper has the contribution to present a new performance measurement model considering the organization theory, the dynamic capabilities.

• Korean Institute of Interior Design Journal
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• v.21 no.1
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• pp.195-202
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• 2012

This study aimed to analyze the types and characteristics of space forms according to performance types in the space of performing arts centers through the cases of modern performing arts centers. As for the space forms according to the performance forms, the performing arts centers devoted to dramas made a small space or turned into multi-purpose ones entering the modern days. Added to the proscenium, the main stage, was the back stage for the stage background. The area of the stage and auditorium grew similar with some kind of separation between the stage and audience. The concert halls have close relationships with the audience and their stage contacts the auditorium on many sections. The stage space is smaller than the auditorium and usually either the complex or entry type. In the opera theater, they commonly create a space for social gathering in addition to the main stage of proscenium, back stage, side stage and auditorium. They're also distinct from other performing centers for having an orchestra pit between the stage and audience. The stage is twice as big as the auditorium and the separate type. In today's performing arts centers, the sizes of the stage and auditorium can vary widely, and the performances of many different genres are put to multiple purposes.

• Korean Institute of Interior Design Journal
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• v.21 no.5
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• pp.328-335
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• 2012

Due to development of digital technology, a concept of stage design management is being changed. In addition, stage management technique is changing a viewpoint of the audience watching a stage through the convergence of analogue and digital technology. Three-dimensional media such as LED and hologram and works combining with previous stage performances are rising, and the audience's requirements about spectacles on the stage are increasingly higher. Interaction between a stage, audiences and actors is a communication tool by a work story and its direction. In other words, stage design should newly focus on not only concluded work story but also comprehensive delivery of direction and the expression and extreme delivery. Therefore, this study aims to examine how to combine analogue and digital direction elements in the stage design. To this end, this study looks into everything the audience feels through performances and analogue and digital elements directed for performances and then analyzes and arranges them to present a possibility of various types of work performances. Stage structure, set, and lighting that are analogue direction elements are the basis of stage performance. Analogue direction elements mean a media vehicle that can differentiate except for basic direction of each work. This study aims to analyze new performance culture when analog and digital direction elements are combined through stage performance and a possibility of new stage performance. In addition, through this it desired to seek for a development possibility of Korean leisure culture and art culture. As the work cases, this study shows 10 works through actual stage performances held in Korea and introduces elements directed in those works.

• Korean Institute of Interior Design Journal
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• v.19 no.3
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• pp.180-187
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• 2010

The purpose of this study was to examine the application tendency of the western classical style which appears in contemporary performing arts centers. The types of space in performing arts centers were investigated according to the times. There were somewhat fixed stage and auditorium types for each period ; the ancient times had the arena stage and round auditorium, the Renaissance the proscenium stage and the U-shaped auditorium, the Elizabethan period the thrust stage and polygonal auditorium, and the modern times the proscenium and apron stage, the horseshoe and fan type auditorium. Today since the purposes of performance are multiple, a variety of stage types are applied to each performing arts center. They use various spaces and performances of multiple purposes by moving and transforming the stage and auditorium according to the kinds of performance as a variation of the arena and proscenium stage. Recently there appear complex performing arts centers that can plan performing spaces of diverse sizes and forms to fit the functions of a performance in a large building. Since they put on performances in a large space according to the characteristics of the kind of performance, the intentions and goals of the performance are well delivered to the audience.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.975-978
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• 2007

This paper investigates stage acoustics in concert halls for ensemble performance in terms of stage support parameters. A concert hall with large stage area was selected. Objective measurements were carried out according to Gade's methods for investigating stage support (ST1). The sound field on the stage was evaluated using stage and audience acoustical parameters. According to the positions at stage, different acoustical characteristics were found. Higher ST1 and lower $IACC_{E3}$ were measured near side and rear stage walls. In case of conductor/soloist vs. orchestra player, objective measurement of acoustical parameters shows that early sound fields depend on the source-receiver distance but late sound fields depend on the location of side and rear walls. In addition, in-situ evaluation of the trio instrumentalists was carried out. Results show that ensemble is favored by higher early reflection of sounds and sound diffusion affecting ‘blending’ of their performance.

• International Journal of Air-Conditioning and Refrigeration
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• v.17 no.3
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• pp.107-113
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• 2009

The objective of this study is to investigate performance characteristics of a household refrigerator using a two-stage compression cycle. The performance of the two-stage compression cycle was measured by varying the compressor speed, condensing temperature, and evaporating temperature. The COP of the two-stage compression cycle was analyzed and then compared with that of the single-stage compression cycle. The optimum combination of compressor speeds for a low- and a high-stage was determined. The COP of the two-stage compression cycle using a PTC (parallel two-stage compression) method was 5.85% higher than that of a STC (serial two-stage compression) method at optimum operating conditions.

• 연구논문집
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• s.25
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• pp.77-90
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• 1995

For improving performance of heat pump system, researcher has adapted 2-stage economizer cycle and developed a high-efficiency screw compressor, new working medium(non-azeotropic mixed refrigerant) and counterflow heat exchangers operating with a small temperature difference. Target of this study is development of high performance heat pump system with the 2-stage economizer system using the non-azeotropic mixed refrigerant. For the purpose of excuting target, we constucted computer simulation programs, compared and examed various types of cycle and non-azeotropic mixture. Based on the results from computer simulation we selected optimum mixtures and reflected design and production process of performance test equipment with the 1-stage econmizer system. In order to accomplish the final target, design and production of the 2-stage economizer system, we performed pilot test using the 1-stage economizer performance test system and finally design and production of the 2-stage economizer system.