• 한국전자파학회논문지
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• 제18권1호
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• pp.15-23
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• 2007

본 논문에서는 six-port 위상 상관기와 신호 검파부 그리고 I 및 Q 채널 신호를 복조하는 간단한 구조를 갖는 six-port 직접 변환 QPSK 수신기를 설계하고 제작하였다. Six-port 위상 상관기의 출력 단자간 출력 위상 신호를 해석하고, 출력 단자 신호 간 $90^{\circ}C$ 위상 관계로부터 QPSK신호를 복조하는 간단한 회로의 직접 변환 수신기 구조를 갖는다. Six-port 위상 상관기는 $90^{\circ}C$ 하이브리드 branch line 및 전력 분배기를 가지며, $11.7{\sim}12.0\;GHz$ 주파수 대역에서 설계된 six-port 위상 상관기의 출력 신호는 $^{\circ}$ 이내의 양호한 위상 오차 특성을 갖는다. 또한 직접 변환 수신기 구성 소자간 양호한 정합도 및 진폭 특성에 의해 약 $5^{\circ}$ 이내의 위상 오차를 갖는 I, Q 데이터를 복원하였다.

• 한국정보통신학회논문지
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• 제14권11호
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• pp.2391-2396
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• 2010

본 논문에서는 국부발전 신호와 수신 RF 신호 전력을 제어할 수 있는 전력제어 6단자 소자를 구성하고 설계 제작하였다. 가변적인 6단자 수신 신호 전력을 제어하여 일정한 전력 세기를 갖는 6단자 소자 출력 신호로 유지하여 전력 검파기의 포화 및 성능 열화를 방지할 수 있는 직접변환 6단자 구조를 제안하였다. 이를 위하여 직접변환 수신방식의 성능을 개선하고 유지할 수 있는 전력제어 6단자 소자를 해석하고, 전력제어 소자와 6단자 소자를 구현하였다. 제작된 전력제어 6단자소자는 1.69 GHz주파수 대역에서 36 dB의 전력 제어와 약 1.6 dB 이내의 이득차, 그리고 약 $4^{\circ}$ 이내의 위상차를 갖는 양호한 수신 전처리기 성능을 나타내었다.

• 한국정보통신학회논문지
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• 제14권12호
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• pp.2615-2621
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• 2010

본 논문에서는 메타물질 구조 다중대역 6단자 위상상관기를 설계하고 제작하였다. 이중 주파수 대역에서 신호를 수신 처리할 수 있는 집중소자형 메타물질 구조를 해석하고, 해석된 결과를 기반으로 다중대역 직접변환 수신 전처리기에 적합한 소형화 메타물질 구조 6단자 위상상관기를 제안하고 구현하였다. 다중대역 6단자 위상상관기를 구성하는 저항성 전력 분배기와 메타물질 $90^{\circ}$ 하이브리드 결합기의 산란 계수를 기반으로 동일한 특성을 갖는 6단자 위상상관기 구성 요소를 제작하고 측정하였다. 측정된 메타물질 구조 6단자 위상상관기는 모의실험 결과와 일치하였으며, 이중 주파수 대역에서 -20 dB 이하의 정합과 1 dB 이내의 전달 이득차, 그리고 ${\pm}4.1^{\circ}$ 이하의 전달 위상차 특성으로 양호한 다중대역 6단자 위상상관기 성능을 나타내었다.

• 대한안전경영과학회지
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• 제17권1호
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• pp.309-320
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• 2015

This study is an empirical study on the relationships among success factors of six sigma(support of top management, education and training, performance-based reward, customer and quality focused thought), job satisfaction, and quality performance. In particular, mediating effect of job satisfaction on the relationship between success factors of six sigma and quality performance is empirically analysed to find causes and impacts among these variables. A survey was conducted on the employees working in 'H' company which is applying six sigma at Ulsan City. The survey questionnaires were sent to 300 people and 216 of them were returned. Data obtained was analyzed with SPSS 18.0. The study results are as follows: First, there were positive relationships between critical success factors of six sigma(except support of top management) and job satisfaction. Second, there was also a positive relationship between job satisfaction and quality performance. Third, there were also positive relationships between critical success factors of six sigma(except support of top management) and quality performance. Finally, job satisfaction were full mediating effects on the relationship between critical success factors of six sigma(education and training, performance-based reward) and quality performance. Critical success factors of six sigma(customer and quality focused thought) had a partial mediating effect on quality performance. On the other hand, support of top management had no mediating effect on quality performance.

• 대한산업공학회지
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• 제32권4호
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• pp.268-278
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• 2006

Ten years have passed since Samsung SDI and LG Electronics introduced six sigma. Six sigma spreads on the wide industry areas such as service and public sectors as well as manufacturing industry. Six sigma speaks for Korean enterprise's management innovation now. Then, can we evaluate that Korean enterprise's six sigma has settled down successfully? This study compares Korean enterprise's six sigma with those of Japanese and American enterprises in the view of leadership, project, people, and methodology. We suggest five topics for the successful settlement of six sigma in Korean enterprises; 1) Role of executives and managers should be changed more actively, 2) Strategy-connected projects should be excavated, 3) Utilization and development plan should be made for black belt and master black belt, 4) Six sigma methodology should be advanced, especially DFSS methodology, and finally 5) Several innovation methodology should be integrated.

• 품질경영학회지
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• 제35권1호
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• pp.97-112
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• 2007

Six Sigma methodology has been evolved since it was first introduced in late 1980's and the number of company which adopts Six Sigma is getting increased. Therefore, it is timely that ire review research papers on Six Sigma extensively. We review 85 papers published in Korea by April 2006 and classify them based on research contents and methodology. We suggest future research issues and fields which can adopt Six Sigma methodology.

• 경영과학
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• 제24권1호
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• pp.147-160
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• 2007

Six Sigma's concept has long been used as an effective way of restructuring the management process of a firm. In literature regarding Six Sigma, a number of successful cases were reported, where Six Sigma based management activities could enhance firm's strategic performance dramatically for year. However, there exist very few researches investigating the effect of Six Sigma on process innovation and quality improvement. Therefore this study propose a research model testing whether Six Sigma innovation could improve process innovation and quality improvement by industrial classification. We collected 332 valid questionnaires from expert in Six Sigma activities, and applied PLS. Empirical results showed that Six Sigma activities could contribute to process innovation and quality improvement.

• 방송과미디어
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• 제11권1호
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• pp.78-85
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• 2006

Cognitive radio is a paradigm for wireless communication in which either network of wireless node itself changes particular transmission or reception parameters to execute its tasks efficiently without interfering with the licensed users. This paper represents a performance of the cognitive radio technology on dual polarized MIMO system using six-port receiver. Six-port technology is well known direct conversion receiver. In this paper, a six-port phase discriminator based polarization signal separation is shown. That is, the SER(Symbol Error Rate) performance is improved using polarization separator and simple receiver architecture is proposed applying six-port receiver. The six-port technology has priority to adapt changeable frequency system and variable environments for cognitive radio. In general, dual polarized MIMO system has good capacity and quality using polarization separator [1].

• 대한안전경영과학회지
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• 제14권1호
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• pp.179-187
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• 2012

This paper presents a six sigma application case study for an automobile PCSV manufacturing process using rolled throughput yield improvement activity. Hidden factor and first yield concept is introduced and DMAIC procedure is implemented to maximize the first pass yield. The result of the six sigma project amounts to the reduction of failure cost of 0.1 billion won per year in the PCSV manufacturing process. This paper can benefit six sigma practitioners in some ways.

• 한국위성정보통신학회논문지
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• 제1권1호
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• pp.59-64
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• 2006

본 논문에서는 직접 변환 방식인 six-port의 RF 출력 신호를 검파하고 요구 대역폭에서 입력 주파수 신호에 대한 진폭 및 위상 신호를 선형적으로 출력하는 광역 power detector를 설계 제작한다. Six-port 출력단에 접속되는 power detector는 높은 정합도를 갖고 반사파로 인한 Six-port 간 위상 불일치를 방지하고, 넓은 대역폭에서 낮은 VSWR을 유지하여야 하는 광역 특성을 갖는 power detector 설계가 필요하다. 광역 정합을 위하여 사용 주파수 대역에 따라 강제 정합과 다단 LC 정합 회로, 그리고 isolator를 사용한 낮은 VSWR 특성을 갖는 설계 방법을 비교 분석한다. 설계 제작된 power detector의 주파수 대역에 대한 동적 동작 영역(dynamic range) 성능을 측정하여 Six-port의 수신 전송 신호 검파기로 활용될 수 있는 타당성을 평가한다.