• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 B
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• pp.720-722
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• 2002

Superconducting synchronous motor using HTS(high-temperature superconducting) field windings has a lot of advantages over LTS(Jow-temperature superconducting) synchronous machine. A recently developed 5000[hp] HTS motor represents 1/2 reduction in weight and volume compared to an induction type conventional machine. Furthermore. 40% machine loss is reduced compared to the industry average. Based on a conceptual design, a 100[hp] HTS synchronous motor is modeled by F.E.M(Finite Element Method) and the performance is predicted in this paper

• Journal of Information Technology Applications and Management
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• 제11권4호
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• pp.1-23
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• 2004

This study identifies communication patterns of groups using synchronous text communication medium for their group decision-making, and examines how these patterns are associated with creative solutions to problems. Our research suggests that certain communication behavior of groups, when appropriately organized, can be of help in enhancing creative production of outcomes. A qualitative study was conducted on communication patterns based on an analysis of text-based electronic conversation protocols. Specifically this research tried to overcome existing studies on electronic groups by focusing on interactive process of communication among participants. The major study conclusion; are: (1) The production of creative outcome may depend on the process or sequence of discussion among group members with synchronous text communication medium. That is, proper interactive responses and appropriate control of the discussion process are essential to obtain a high level of performance. (2) It is importantto make discuss rules based on meta-cognitive and interactive protocols in the early stage. Explicit rules relating to internal group processes as well as communication medium use are even more important to groups with electronic communication medium than face-to-face groups.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2013년도 전력전자학술대회 논문집
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• pp.413-414
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• 2013

An LLC resonant converter is widely used due to many advantages over others. However, it is still not used in high current applications because it is difficult to drive the synchronous rectifiers. In this paper, a novel gate driving sheme for secondary-side synchronous rectifiers is introduced and its simulation results are also presented

• 반도체디스플레이기술학회지
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• 제18권1호
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• pp.59-64
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• 2019

Recently, time synchronous has become important for satellite launch control facilities, multiple thermal power plants, and power system facilities. Information from time synchronous at each of these industrial sites requires time synchronization to control or monitor the system with correlation. In this paper, IRIG-B codes, which can be used for time synchronous, are used as specifications in IRIG standard 200-16. Signals from IRIG-B120 (Analog), IRIG-B000 (Digital), and one PPS are output from GPS receiver. Using the signal from IRIG-B120 (Analog), it passes through the signal from the analog amplifier and generates one PPS signal using the field-programmable gate array. The FPGA is used cyclone EPM570T100I5N. According to IEEE regulations, the error of one PPS is specified within 1us, but in this paper, the error is within 100ns. The output of the one PPS signal was then compared and tested against the one PPS signal on the GPS receiver to verify accuracy and reliability. In addition, the proposed time synchronous is simple to construct and structure, easy to implement, and provides high time precision compared to typical time synchronous. The output of the one PPS signals and IRIG-B000 signal will be used in many industry sectors.

• 조명전기설비학회논문지
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• 제27권2호
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• pp.45-53
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• 2013

In this paper, we analyze the typical phase voltage and line current waveform characteristics of the distribution system with 3 phase small synchronous generation source in case with load and non-load group, in order to investigate the power quality for end load connected of generation source. As demonstrated by our experimental results, the distortion and power quality of phase voltage and line current waveform were relatively good for low voltage 3 phase model grids connected of 3 phase small synchronous generation source in case with non-load group. However, distortion and power quality of voltage and current waveform was poor for low voltage 3 phase model grids connected to 3 phase small synchronous generation source in the load group with some phase voltage and frequency difference. From the above results, we conclude that the phase voltage and frequency of 3 phase generation source must be identical to that of distribution system source to maximize the power quality. Also, special attention is required in case of having load group or non-load group to 3 phase generation source.

• 한국데이타베이스학회:학술대회논문집
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• 한국데이타베이스학회 1999년도 춘계공동학술대회: 지식경영과 지식공학
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• pp.95-102
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• 1999

The web-based group collaborative systems are emerging as enterprise-wide information systems. Since data in group collaborative systems are apt to be shared among multiple concurrent users and modified simutaneously by them, the web-based group collaborative systems must support synchronous collaboration in order to provide users with synchronized and consistent views of shared data. This Paper proposes an active web server which can facilitate synchronous collaboration in web-based group collaborative systems. To accomplish such a goal, the active web server manages dependency relationships between shared data and web browsers referencing them and actively propagates changing details of the shared data to all web browsers referencing them. And, this paper examines usefullness and effectiveness of the active web server to apply it to the ball-bearing design example of concurrent engineering design systems. The prototype system of the active web server is developed on a commercial Object-oriented Database Management System (ODBMS) called OBJECTSTORE using the C＋＋ programming language.

• 한국지능정보시스템학회:학술대회논문집
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• 한국지능정보시스템학회 1999년도 춘계공동학술대회-지식경영과 지식공학
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• pp.95-102
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• 1999

The web-based group collaborative systems are emerging as enterprise-wide information systems. Since data in group collaborative systems are apt to be shared among multiple concurrent users and modified simutaneously by them, the web-based group collaborative systems must support synchronous collaboration in order to provide users with synchronized and consistent views of shared data. This paper proposes an active web server which can facilitate synchronous collaboration in web-based group collaborative systems. To accomplish such a goal, the active web server manages dependency relationships between shared data and web browsers referencing them and actively propagates changing details of the shared data to all web browsers referencing them. And, this paper examines usefullness and effectiveness of the active web server to apply it to the ball-bearing design example of concurrent engineering design systems. The prototype system of the active web server is developed on a commercial Object-oriented Database Management System (ODBMS) called OBJECTSTORE using the C++ programming language.

• 대한종양외과학회지
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• 제14권2호
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• pp.83-88
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• 2018

Purpose: Double primary colorectal cancer (CRC) and gastric cancer (GC) represent the most common multiple primary malignant tumors (MPMT) in Korea. The recognition and screening of hidden malignancies other than the primary cancer are critical. This study aimed to investigate the clinicopathologic characteristics and survival rates in patients with synchronous or metachronous double primary CRC and GC. Methods: Between January 1994 and May 2018, 11,050 patients were diagnosed with CRC (n=5,454) or GC (n=5,596) at Gil Medical Center. MPMT and metastatic malignant tumors were excluded from this study. A total of 103 patients with double primary CRC and GC were divided into two groups: the synchronous group (n=40) and the metachronous group (n=63). The incidence, clinicopathologic characteristics, and survival rate of the two groups were analyzed. Results: The incidence of synchronous and metachronous double primary CRC and GC was 0.93%. Double primary CRC and GC commonly occurred in male patients aged over 60 years with low comorbidities and minimal previous cancer history. There were significant differences between the synchronous and metachronous groups in terms of age, morbidity, and overall survival. Metachronous group patients were 6 years younger on average (P=0.009), had low comorbidities (P=0.008), and showed a higher 5-year overall survival rate (94.8% and 61.3%, P<0.001) in contrast to synchronous group. Conclusion: When primary cancer (CRC or GC) is detected, it is important to be aware of the possibility of the second primary cancer (GC or CRC) development at that time or during follow-up to achieve early detection and better prognosis.

• Journal of Gastric Cancer
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• 제9권4호
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• pp.256-261
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• 2009

목적: 진단 기술의 발전과 함께 위암 환자에서 동시성과 이시성암이 발견되는 빈도가 증가하고 있다. 본 연구에서는 위암에서 발견된 동시성과 이시성암의 임상병리학적 특성과 임상적 의의에 대하여 알아보고자 하였다. 대상 및 방법: 1998년 1월부터 2008년 3월까지 조선대학교병원에서 위암으로 진단된 환자들의 의무기록을 후향적으로 분석하였다. 결과: 1,048명 위암 환자 중 38명(3.6%)에서 동시성과 이시성암이 있었다. 38명 중 16명(42.1%)은 동시성암이었고 22명(57.9%)은 이시성암이었다. 위암과 이차성 원발암 간의 평균 시간간격은 $27.08{\pm}31.25$개월이었다. 가장 흔한 중복암은 폐암(8/38, 21.1%)과 대장암(8/38, 21.1%)이었다. 27명의 환자가 위암에 대하여 수술적 치료를 하였으며 이 중 5명(18.5%)은 동시성암, 22명(81.5%)은 이시성암이었다. 평균 생존 기간은 49.8개월이었으며 동시성암의 경우는 24.6개월 이시성암의 경우는 68.1개월이었고 이들의 3년 생존율은 동시성암, 이시성암 각각 33.3%, 81.1%였다. 결론: 위암에서의 이차성 원발암 진단에 대한 진단에 있어 충분한 수술 전 검사를 통한 동시성암의 발견과 지속적인 추적검사를 통한 이시성암의 발견을 위해 주의를 기울여야 한다.

• Journal of Power Electronics
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• 제9권2호
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• pp.146-155
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• 2009

The static frequency converter (SFC) systems are used as a method of driving large synchronous machines in many power and industrial plants. In this paper, new control algorithms of SFC systems for starting gas turbo sets are proposed for a four quadrant operation: start-up at standstill; an acceleration up to the speed of the rated voltage; field weakening to reach the rated speed; synchronization to the main alternating current (AC) source; and dynamic braking to stop safely within the rating of the synchronous machine. Experimental results show that the proposed algorithms are proper and effective.