• Proceedings of the Korean Society for Quality Management Conference
• /
• 2010.04a
• /
• pp.33-48
• /
• 2010

The purpose of this study is to empirically analyze the productivity change of the 10 Single PPM Certification Company in the 3 Industry(Electronics, Motor-Parts, Machines). In this study, Productivity change over the time in Korean small and medium sized firms in the 3 industries by the bootstrapped Malmquist Productivity Index(MPI). The traditional Malmquist Productivity Index(MPI) and Data Envelopment they could lead to wrong evaluations of the efficiency and productivity scores. In this paper, DEA and a MPI are combined with a bootstrap method in order to provide statistical inferences that analyze the performance of the Single PPM Certification Company. The data cover the period between 2004 and 2007. The result of this paper reveals : 1) The electronic industries(Motor-Parts, Machines). 2) average productivity Progress of the 7DMU(Electronics), 1DMU(Motor-Parts) and none(Machines).

• Proceedings of the KSR Conference
• /
• 2010.06a
• /
• pp.432-436
• /
• 2010

This paper investigates the productivity growth in Korean railway lines. The productivity growth is calculated by a process of measuring of pure efficiency change index(PECI), scale efficiency change index(SECI), and technical change index(TCI), using Data envelopment analysis (DEA) method. The data cover the period 1990~2007; 1990~2003 are the pre-structural reform years and the post-structural reform years are 2005~2007. The framework for the analysis is Malmquist Productivity Index (MPI) of the to investigate the impacts of structural reform on productivity growth, respectively. The inputs considered are the length of operating line, the number of staff, the number of coach and wagon, and the outputs are the trains movement of passenger and freight, and the traffic of passenger and freight.

• Proceedings of the KSR Conference
• /
• 2007.11a
• /
• pp.95-100
• /
• 2007

The traction motor for High Speed Train is being required reliability and stability for high-speed operation. And also required low noise level, high performance, compact size owing to the space and weight limitation for attaching to train, etc. As a result of requiring the low noise level and high power capacity, it is adopted forced-air-ventilation insead of self-ventilation that is generally used on electric multiple unit. Traction motor is cooled by cooling air through the air-ventilation hole. When the traction motor is operated with forced-air-ventilation, there is some abnormal noise in the specific RPM. This paper is dealing with the method to reduce the resonance phenomena by adopting the rotor blade.

• Journal of Korea Ship Safrty Technology Authority
• /
• s.37
• /
• pp.2-11
• /
• 2014

본 연구에서는 최근, 전기자동차 및 소형 레저용 선박을 중심으로 연구가 진행 중인, 대용량 이차전지의 용량 증대를 위하여 필요한 내부 전극 접합 기술에 관하여 연구하였다. 종래의 초음파 용접으로 적층할 수 있는 적층량의 한계를 극복하기 위한 방안으로 전극 소재에 직접 가열을 통한 용접 방법이 아닌 용가제 금속을 적용하여 전극을 접합시켜, 통전성과 인장강도를 증대시킴과 동시에 열적요인으로 인한 전극표면에 화학적 활성물질의 변성을 최소화할 수 있는 저온 접합 방법에 대하여 연구하였다. 부연하여 용접을 위하여 무리하게 출력을 상승시킬 경우 용접열의 영향으로 전극의 변형 및 활성물질의 변성을 야기함과 동시에 최종 페키징 이후 출력저하, 발열 등, 배터리의 안정성을 저하시키는 요인으로 작용한다. 따라서 본 연구에서는 고주파 유도가열을 통한 유도 가열 방식의 접합 방법과 용융 도금을 통한 용가제 금속의 전처리를 통한 종래와는 차별화된 전극접합 방법을 소개한다.

• Proceedings of the KIEE Conference
• /
• 2015.07a
• /
• pp.266-267
• /
• 2015

본 논문에서는 MMC-HVDC에서 스위칭 디바이스의 전류용량을 고려하면서 순환전류를 제어할 수 있는 새로운 제어기법을 제안한다. 불평형 전압 조건에서 유효전력과 무효전력에는 기본 주파수의 두 배에 해당하는 주파수 성분이 포함된다. 따라서 유효전력 제거를 위해 역상분 전류를 주입하되, 기존의 $I_{dc}/3$가 아닌 각 암의 유효전력을 계산하여 지령치를 인가하는 새로운 방식의 제어기법을 제안한다. 제안한 기법은 PSCAD/EMTDC를 이용한 시뮬레이션을 통하여 검증하였다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2001.11b
• /
• pp.296-299
• /
• 2001

Data on the oil spill recovery from the water surface by light floating electromagnetic plants using a new magnetic adsorbent are given. The feasibility scope for further oil recovery from such gathered mixtures(oil + adsorbent), reuse of this magnetic adsorbent and its property reclaiming and recycling were shown. The basic conception of the oil spill recovery and efficiency of this method were set forth.

• Journal of Korean Society for Quality Management
• /
• v.38 no.3
• /
• pp.393-407
• /
• 2010

The purpose of this study is to analysis relative efficiency and efficiency in process of time. Thus we use panel data of 34 local public medical centers between 2003 and 2005 to use DEA and Malmquist analysis. The result of our this study is as flow; first, The results of static efficiency of 34 local public medical centers show 10 CCR model and 23 BCC model which is difference of efficiency by economic of scale. Second, a cause of increased efficiency is not only change of technology but also change of efficiency to management system index show between 2003 and 2005 by Malmquist analysis and contracting-out is higher than direct management between 2004 and 2005. That means efficiency of local public medical centers is their own effort and innovation not government subsidies.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2002.11a
• /
• pp.268-271
• /
• 2002

The goal of the research is to study and describe a new stressed state of High Temperature Superconducting (High-Tc) YBCO Films, to create of SQUIDs (Superconducting Quantum Interference Device) on the bases of these Films with maximal sensitivity. The experimental investigation of the stressed films grown by laser ablation method and its properties, the fabrication of the dc-SQUIDs with maximal sensitivity on the bases of the stressed YBCO films were carried out. The stressed film having the value of the critical current density $J_{c}=3{\cdot}10^{5}A/cm^{2}$ was the more stable than others.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.35 no.4
• /
• pp.48-54
• /
• 2012

In this paper, quantitative and systematic procedures for establishing Key Performance Indicators (KPI's) of R&D departments are presented. The proposed methodology is composed of 4 steps : 1) identification of critical success factors, 2) identification of potential KPI's, 3) determination of KPI's and 4) monitoring and execution. A Strategy Map has been presented to better align KPI's with a company's competitive strategies. Also, Analytical Hierarchy Planning (AHP) is used to determine weights of KPI's and Data Envelopment Analysis (DEA) is used to analyze the effectiveness of R&D departments. To demonstrate its validity of the proposed method, it has been applied to the R&D divisions of a semiconductor company.

• Proceedings of the KSR Conference
• /
• 2009.05a
• /
• pp.378-381
• /
• 2009

This paper investigates the productivity growth in Korean railway transport. The productivity growth is calculated by a process of measuring of pure efficiency change index(PECI), scale efficiency change index(SECI), and technical change index(TCI), using Data envelopment analysis (DEA) method. The data cover the period 1999$\sim$2006; 1999$\sim$2003 are the pre-structural reform years and the post-structural reform years are 2004$\sim$2006. The framework for the analysis is Malmquist Productivity Index (MPI) of the to investigate the impacts of structural reform on productivity growth, respectively. The inputs considered are the length of operating line, the number of staff, the number of coach and wagon, and the outputs are the trains movement of passenger and freight, and the traffic of passenger and freight. Results indicate that Korean railway experienced a annual productivity growth of approx. 3% after the structural reform.