• 제목/요약/키워드: internal performance

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내부 열교환기를 이용한 R744용 초임계 냉동사이클의 성능 분석 (Performance Analysis of R744 (Carbon Dioxide) Transcritical Refrigeration System Using Internal Heat Exchanger)

  • 손창효;오후규
    • Journal of Advanced Marine Engineering and Technology
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    • 제33권4호
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    • pp.459-465
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    • 2009
  • This paper considers the influence of internal heat exchangers to the efficiency of a refrigerating system. These internal heat exchangers(liquid-suction or suction-line heat exchangers) can, in some cases, yield improved system performance while in other cases they degrade system performance. A steady state mathematical model is used to analysis the performance characteristics of refrigeration system with internal heat exchanger. The influence of operating conditions, such as gas cooler pressure and evaporation temperatures, superheat in the evaporator and temperature of gas cooler outlet, to optimal dimensions of the heat exchanger is also analyzed in the paper. The main results were summarized as follows : the mass flowrate of R744, inner diameter tube and length of internal heat exchanger, and effectiveness have an effect on the cooling capacity, compressor work and RCI(Relative capacity index) of this system. With a thorough grasp of these effect, it is necessary to design the R744 compression refrigeration cycle using internal heat exchanger.

내부마케팅이 직무만족과 인지적 기업성과에 미치는 영향 : 한국수자원공사를 중심으로 (Internal Marketing Approach to Internal Satisfaction and Cognitive Organization Performance : The Case of Korean Water Resources Corporation)

  • 석영기
    • 한국콘텐츠학회논문지
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    • 제14권1호
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    • pp.374-385
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    • 2014
  • 본 연구의 목적은 한국수자원공사의 종업원 직무만족에 영향을 미치는 내부마케팅 요인 중 교육훈련, 보상제도, 의사소통, 권한위임의 선행변수가 직무만족과 인지적 기업성과에 미치는 영향을 파악하고, 내부 마케팅, 직무만족, 인지적 기업성과 등에 대한 문헌적 고찰과 한국수자원공사 내부고객을 대상으로 설문조사를 통한 실증분석을 실시하여 한국수자원공사 고객만족도 향상을 위한 시사점을 제시하는 것이다. 한국수자원공사의 직무만족을 설명하는 4개의 요인에 대한 로지스틱 회귀분석 결과, 교육훈련, 보상제도, 의사소통요인이 유의한 것으로, 권한위임은 유의하지 않은 것으로 나타났고, 인지적 기업성과의 경우, 교육훈련과 의사소통요인이 유의한 것으로 보상제도와 권한위임요인은 유의하지 않은 것으로 나타났다. 내부마케팅요인이 한국수자원공사의 성공에 적용될 수 있음을 알 수 있었다.

Social Supply Chain Practices and Companies Performance: An Analysis of Portuguese Industry

  • PINTO, Luisa
    • 유통과학연구
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    • 제17권11호
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    • pp.53-62
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    • 2019
  • Purpose: This research aims to study the internal and external social practices of supply chain management along with economic and social performance of eight Portuguese companies from different industrial sectors. Through empirical data derived from eight case studies, five research propositions are suggested and tested. Research, design, data and methodology: The data was collected through 22 semi-structured interviews with general, procurement, and environmental/safety managers from eight companies from different industrial sectors. Secondary data was collected from reports, websites, and companies' internal documentation. Results: The analysis identifies the most important social practices considered by managers, as well as the performance measures that are most appropriate and most widely used to evaluate the influence of social practices on corporate economic and social performance. The results support four of the five propositions of this research. Companies' economic and social performance are affected by the implementation of social practices into the supply chain, namely the internal social practices. Conclusions: The findings confirmed that there is a positive relationship between internal social practices and economic performance. Internal social supply chain practices contribute to improve social performance. It also identifies the social practices which have negative effects on focal company performance.

내부열교환기 및 전자팽창장치를 적용한 가변속 이산화탄소 사이클의 냉방성능에 관한 실험적 연구 (Experimental Study on the Cooling Performance of a Variable Speed $CO_2$ Cycle with Internal Heat Exchanger and Electronic Expansion Valve)

  • 조홍현;류창기;김용찬
    • 설비공학논문집
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    • 제17권3호
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    • pp.209-215
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    • 2005
  • Since a transcritical $CO_2$ cycle shows lower performance than conventional air conditioners in the cooling mode operation, it is required to enhance the performance of the $CO_2$ cycle by applying advanced technologies and optimizing components. In this study, the cooling performance of a $CO_2$ system measured by varying refrigerant charge amount, compressor frequency, EEV opening and length of internal heat exchanger. As a result, the cooling COP of the basic system without internal heat exchanger was 2.1. The cooling performance of the modified cycle applying internal heat exchanger improved by $4-9\%$ over the basic cycle.

액-가스 열교환기를 이용한 R170(에탄)용 냉동시스템의 성능 특성 (Performance Characteristics of Refrigerant R170(Ethane) Refrigeration System Using Liquid-gas Heat Exchanger)

  • 구학근
    • 동력기계공학회지
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    • 제20권5호
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    • pp.78-85
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    • 2016
  • This paper considers the influence of internal heat exchangers to the efficiency of a refrigerating system using R170. These liquid-gas heat exchangers(internal or suction-line heat exchangers) can, in some cases, yield improved system performance while in other cases they degrade system performance. A steady state mathematical model is used to analysis the performance characteristics of refrigeration system with internal heat exchanger. The influence of operating conditions, such as the mass flowrate of R170, inner diameter tube and length of internal heat exchanger, to optimal dimensions of the heat exchanger is also analyzed in the paper. The main results were summarized as follows : the mass flowrate of R170, inner diameter tube and length of internal heat exchanger, and effectiveness have an effect on the cooling capacity, compressor work and RCI(Relative Capacity Index) of this system. Exception for the effect of inner diameter, the RCI of R170 with respect to refrigerant mass flowrate, the length and effectiveness of internal heat exchanger is about 2.1~3.3% higher than that of R13 at the same experimental conditions. With a thorough grasp of these effect, it is necessary to design the R170 compression refrigeration cycle using internal heat exchanger.

Digital Transformation, Manipulation of Asset Evaluation and M&A Performance: Discussion on the Intermediary Effect of Internal Control

  • Chen Chen;Hee-Jung Lee;Nan Hui;Xue-Hua Qian
    • 아태비즈니스연구
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    • 제14권1호
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    • pp.1-19
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    • 2023
  • Purpose - The purpose of this study was to examine the internal relevance between digital transformation, manipulation of asset evaluation and corporate M&A performance and further explores the impact path of manipulation of asset valuation on corporate M&A performance. Design/methodology/approach - This study based on the financial data of A-share listed companies in Shanghai and Shenzhen Stock Exchanges from 2013 to 2021. Findings - First, manipulation of asset evaluation is negatively correlated with M&A performance. Second, Digital transformation significantly weakens the negative correlation between manipulation of asset evaluation and corporate M&A performance. Third, The effectiveness of internal control plays a partially intermediary role in the process of manipulation of asset evaluation affecting M&A performance. Research implications or Originality - Enriching the existing literature on the subject, the study can also provide useful reference for improving the performance of corporate mergers and acquisitions, regulating asset valuation, promoting the digital transformation of enterprises and improving internal control mechanisms, with both theoretical and practical implications.

휜 타입 내부열교환기 적용에 따른 차량용 냉방시스템 성능 특성 (Performance Characteristics of Vehicle Air Conditioning System Using Internal Heat Exchanger with Inner Fin)

  • 김성철
    • 한국산학기술학회논문지
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    • 제14권1호
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    • pp.69-73
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    • 2013
  • 내부열교환기를 이용한 에어컨 시스템은 작동유체인 R134a의 고압측 액상냉매와 저압측 기상냉매의 상호 열교환을 통해 시스템의 응축 효율을 증가시켜 에너지 효율을 개선시킨다. 이는 에어컨 시스템의 성능 향상 및 경량화를 가능하게 하여 차량 연비 향상과 냉매 누출을 최소화할 수 있으며, 또한 현 R134a 대비 대체냉매 (R1234yf 등)의 동등 냉방성능 확보를 가능하게 하는 기술이다. 본 연구에서는 내측 압출 파이프 및 외측 사이 고효율 냉각 휜 (fin)이 삽입된 이중관 형태의 내부열교환기 상세 설계를 위해, 냉각 휜의 높이 및 내측 압출 파이프 내부형상 등의 다양한 형상 설계인자 변경에 따른 열전달 성능 및 압력강하 특성을 살펴보았다. 가장 우수한 내부열교환기 성능은 난류형성을 위한 내측관 형상이 라이너 및 세레이션 겸용 타입이었으며, 이는 내부열교환기가 장착되지 않은 경우보다 냉방시스템 성능이 약 6.4%, 시스템 COP는 약 9.2% 향상된 결과를 나타내었다.

천임계 $CO_2$ 시스템용 코일형 내부 열교환기의 열성능 해석 (Thermal Performance Analysis of Circular Coil Type Internal Heat Exchanger for Transcritical $CO_2$ System)

  • 박병규;김근오;김무근
    • 설비공학논문집
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    • 제14권7호
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    • pp.531-542
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    • 2002
  • Transcritical$CO_2$ systems are under consideration for use as residential/mobile air conditioners. In these systems, an internal heat exchanger is usually adopted to improve both capacity and/or COP of the $CO_2$ system in lower operating pressure range of gas cooler. A program has been developed to analyse the performance of internal heat exchangers using the section-by-section method. The internal heat exchanger of coaxial configuration is first analyzed and fairly good agreements with the data are obtained, And then the internal heat exchanger of multiple circular coil configuration has been investigated. The results obtained from the parametric study provide the guidelines for the initial design and manufacturing concepts of the internal heat exchanger in transcritical $CO_2$ system. Further studies are necessary to develop the heat transfer correlations of carbon dioxide in the tubes to obtain more accurate results.

공항 특수경비조직의 내부서비스품질과 내부고객만족 및 경영성과의 관계 (Relationship between Internal Service Quality and Internal Customer Satisfaction, Management Outcome in Airport Private Security Agents)

  • 김찬선;이지은;조병해
    • 한국콘텐츠학회논문지
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    • 제12권4호
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    • pp.426-437
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    • 2012
  • 이 연구의 목적은 공항 특수경비조직의 내부서비스품질과 내부고객만족 및 경영성과의 관계를 규명하는 데 있다. 이 연구는 2011년 10월 인천소재 공항에서 재직하고 있는 특수경비원들을 모집단으로 설정한 후 유의표집법을 이용하여 최종분석에 이용된 사례 수는 총 282명이다. 연구에 사용된 설문지는 총 43문항으로 구성되었으며, SPSSWIN 18.0을 이용하여 빈도분석, 요인분석, 신뢰도분석, 다중 회귀분석, 경로분석 등을 실시하였다. 설문지의 신뢰도는 Cronbach's ${\alpha}$값이 .686이상으로 나타났다. 결론은 다음과 같다. 첫째, 공항 특수경비조직의 내부서비스품질은 내부고객만족에 영향을 미친다. 즉, 유형성, 대응성, 공감성 활동이 잘 이루어질수록 내부지원만족, 유형성, 대응성 활동이 잘 이루어질수록 직무만족은 증가한다. 둘째, 공항 특수경비조직의 내부서비스품질은 경영성과에 영향을 미친다. 즉, 유형성, 신뢰성, 대응성 활동이 잘 이루어질수록 비재무적성과, 유형성, 신뢰성 활동이 잘 이루어질수록 재무적성과는 증가한다. 반면, 공감성 활동이 잘 이루어지지 않을 경우 재무적성과는 감소한다. 셋째, 공항 특수경비조직의 내부고객만족은 경영성과에 영향을 미친다. 즉, 내부지원만족 활동이 잘 이루어질수록 비재무적성과 및 재무적성과는 증가한다. 넷째, 공항 특수경비조직의 내부서비스품질은 내부고객만족 및 경영성과에 직 간접적인 영향을 미친다. 즉, 내부고객만족은 내부서비스품질과 경영성과를 매개하는 중요한 변수이다.

간호사가 지각하는 내부마케팅활동 정도가 간호사의 이직의도, 간호업무수행 및 간호업무생산성에 미치는 영향 (An Analysis of Nurse's Perception of Internal Marketing Activities Affecting on Nurse's Turnover Intention, Nursing Task Performance and Nursing Productivity)

  • 두은영;서문경애;김인아;임지영
    • 간호행정학회지
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    • 제11권1호
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    • pp.1-12
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    • 2005
  • Purpose: The purpose was to analyze the effects of internal marketing activity factors on nurse's turnover intention, nursing task performance and nursing productivity. Methods: The subjects were 355 nurses who were working at the 3 universities hospital over 1 year. The instruments were used of internal marketing activity factors(Lee, 2001), turnover intension(Lee, 1995), nursing task performance(Park, 1988) and nursing productivity(McNeese-Smith, 1996). Results: The mean score of internal marketing activity factors was 2.79, education and training 2.97, individualization 2.93, communication 2.87, promotion 2.76, work environment 2.63, reward system 2.62, and management vision for employee 2.61. The turnover intention was 3.12, nursing task performance 3.49, and nursing productivity 3.38. The internal marketing activity factors were negatively correlated with turnover intention(r=-0.37, p<0.0001), and positively correlated with nursing task performance(r=0.29, p<0.0001) and nursing productivity(r=0.30, p<0.0001). The key predictor of turnover intension was reward system, education and training, communication, and salary. They explained 35.0% of the total variance. In nursing task performance, communication, management vision for employee, salary and unit explained 26.0% of the total variance. In nursing productivity, communication, reward, education and training, salary, and position explained 24.0%. Conclusions: To increase nurse's nursing task performance and nursing productivity and to decrease turnover intention, it is necessary to concentrate on improving communication and reward system in the internal marketing activity factors. Through these activities, the effectiveness of internal marketing strategies will be enhanced and finally, nursing organizational outcome will be increased.

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