• The Transactions of the Korean Institute of Power Electronics
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• v.13 no.3
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• pp.163-170
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• 2008

Switching characteristics in both linear and nonlinear loads are analysed for a 3-phase voltage disturbance generator applicable to the performance test of custom power devices. Since the line current of the linear load is continuous the natural commutation of the SCR thyristors comprising the generator is carried out with ease. However, in case of nonlinear load the natural commutation scheme is different from that of the linear load due to the discontinuous load current. Through the analysis it is found that a specific switching condition can provide the voltage sag, swell, outage, and voltage unbalance generation in nonlinear load too. The operation of the voltage disturbance generation is described and the usefulness of the generator is verified through simulation and experimental results. It is expected that the generator can be used in the performance test of the custom power devices with low implementation cost and easy control.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.52 no.1
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• pp.56-64
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• 2016

This study analyzed characteristics of officers' watch-keeping during fishing operation at the fisheries training ship KAYA (GT: 1,737 tons, Pukyong National University). It observed fishing works of three officers in wheel house of KAYA. The observations were carried out at the fishing ground 45 miles away from east of Jeju from 7 to 8 January 2010. The works and movements of the officers were recorded with three common video cameras and a 4-channel MPEG-4 Triplex DVR. Recorded data of the working circulation was analyzed by using the post-processing method. As a result of the traffic lines, the average (${\pm}S.D$) of working hour (min) and moving frequency (times), distance (m) and speed (m/min) during setting the net was 11.8 (0.9), 43.7 (8.1), 133.9 (35.8) and 10.5 (0.6), respectively. During trawling the net, it was 100, 241 (39.8), 615.7 (194.6) and 5.2 (1.6), respectively. During hauling the net, it was 17.6 (1.4), 41.0 (7.2), 196.9 (37.6) and 10.7 (0.8), respectively. In addition, it has a different tendency of the instrument usage frequency by the fishing works. During setting, the usage priority was CCTV, ECDIS, RPM and pitch controller, net monitor, GPS plotter, chart room, X-band radar, fish finder and public addressor. During trawling, it was CCTV, ECDIS, fish finder, X-band radar, net monitor, chart room, GPS plotter, RPM and pitch controller, auto pilot and steering, interphone, wind speed and direction indicator, No.1. VHF, navigation light control panel and public addressor. During hauling, it was CCTV, RPM and pitch controller, GPS plotter, public addressor, chart room, net monitor, X-band radar, auto pilot and steering and fish finder.

• 한국HCI학회:학술대회논문집
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• 2006.02b
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• pp.9-13
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• 2006

본 연구는 HD 복합TV 사용자의 시청행태 및 사용자 니즈 분석을 통해 사용자 시나리오를 도출하여 실제 제품에 적용할 수 있는 DTV 인터페이스 디자인의 일반적인 원리를 발견하고 대형 DTV 화면에 적합한 OSD디자인을 개발하여 디지털 복합 TV에 적합한 새로운 디자인 가이드라인을 제안하는 것을 그 목적으로 하고 있다. 이를 위해 DTV 시청환경을 기반으로 PVR, EPF, 녹화, 1394 등 다양한 기능에 대한 사용 시나리오를 정의하고 유저 내비게이션 특성을 반영한 OSD디자인 방향을 검토하였고 개발환경인 50인치 PDP 화면에 적합한 레이아웃을 제작하여 사용자조사를 통해 검증하였다. 사례연구로 최근 이슈가 되고 있는 타임머신 기능 X Canvas PDP의 OSD 디자인을 개발하여 양산용 제품에 적용할 수 있었다. 대표적인 특징으로 복합 TV 의 Gateway 인 홈메뉴, PVR 기능의 핵심인 프로그래스바, 모든 컨텐츠에 일관되게 적용할 수 있는 목록화면, 녹화관련화면에 공통적으로 적용할 수 있도록 폰트,칼라,레이아웃,위젯 정의를 수행하여 각 기능별 화면들이 Package개념으로 Identity를 갖추면서 사용하기 편리하도록 구성하였다. 그리고 이를 통하여 DTV Application Design에 일반적으로 적용할 수 있는 메뉴구조 및 화면디자인 가이드라인을 도출하였고 세계최초로 자사에서 개발한 하드디스크 내장 HD TV Application GUI 의 사용성 및 심미성 측면을 모두 만족시키는 등 DTV GUI 분야에서 주목할 만한 성과를 거두었다.

• Journal of Chest Surgery
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• v.25 no.12
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• pp.1556-1562
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• 1992

Forty two consecutive patients who had had valve replacement with St. Jude Medical prosthesis were studied on a view point of intravascular hemolysis. Patients were consisted of 14 mitral valve replacement, and 7 aortic valve replacement, and 21 double, mitral and aortic, valve replacement. Serum LDH, indirect bilirubin, GOT, hemoglobin levels and ret-iculocyte count were pursued in postopeative 1st day, 3rd day, 7th day, 14th day and 21th day. Postoperatively, all patients were not detected paravalvular leakage on the ech-ocardiographical study. The patients with double valve replacement revealed higher levels of LDH on postopeative 14th day[P<0 05] than those with single valve replacement. Among the patients with single valve replacement, the patients with aortic valve replacement revealed slightly higher levels of entire postopeative data, but considered insignificant. There was correlation between the severity of hemolysis and the size of replaced aortic valve. In the postoperative LDH levels, the patients with small sized-aortic valve[less than 21mm in diameter] replacement revealed higher levels of postoperative 3rd day, 7th day and 14th day than those with large size[more than 23mm in diameter]. The patients with high level LDH of greater than 800 WU /L on postoperative 7th day were 61.9%[26 of 42]. The high LDH frequency of DVR was 71.4%[15 of 21], MVR 50.0%[7 of 14] and AVR, 57.1%[4 of 7]. The level of LDH declined gradualiy thereafter through postoperative 3 weeks. In conclusion, intravascular hemolysis after prosthetic valve replacement was dependent on position of valve replacement and size of valve. And this study supports the conventional valve selection and usage in our hospital. The patients with subclinical hemolysis after valve replacement should be placed on a close observation.

• Journal of Chest Surgery
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• v.22 no.6
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• pp.1025-1035
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• 1989

Since we first performed open heart surgery on December 30, 1986, 126 cases were operated on up to August 31, 1989. Among the 126 cases, 65 cases were congenital heart disease of which 63 were acyanotic disease, and 61 cases were acquired heart disease, most of which were valvular heart disease. The age distribution of congenital heart disease was from 1 years 2 months to 48 years, and males had a slightly higher incidence. The age of acquired heart disease was from a minimum of 15 years to a maximum of 68 years, and the male to female ratio was 1;1.5. Midsternotomy was performed in all cases, and the aortic cannula was inserted through ascending aorta and the venous cannula inserted into the SVC and IVC through the right atrium. Vent was inserted through the right superior pulmonary vein. Cardioplegia solution was used in all cases; it was composed of sodium bicarbonate 3.5 ampule, KCL 14 mEq, 2% lidocaine 2.5 ml, 20 % albumin 50 ml and heparin 1000 units mixed to 950 ml with Hartman solution, and was made to 4oC and infused 10 ml per Kg every 20 minutes. The congenital heart disease had a variety of VSD in 32 cases, ASD 23 cases, PS 6 cases, PDA 2 cases, and one case each of Ebsteins anomaly and tricuspid atresia. The operations performed for acquired heart disease were 4 cases of OMC, 33 cases of MVR, and 5 cases of AVR, and 1 case of AVR with CABG. DVR was perfomed in 13 cases, and triple valve replacement was done in 1 case. Other than these, excision of LA myxoma was 2 cases, and repair of traumatic VSD and removal of a pulmonary embolism were one case each. The surgical mortality was 5 cases[4%], all of which occurred in valve replacement cases. Follow-up study revealed 2 late deaths. One died after a traffic accident and one died due to sepsis after he had received a gastrectomy for ulcer bleeding. The remaining patients were in good condition.

• The Transactions of the Korean Institute of Power Electronics
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• v.10 no.6
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• pp.626-633
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• 2005

This paper proposes a new 2MVA SSFG(Sag Swell Flicker Generator) injecting voltage by using series inverter. The proposed SSFG composes series inverter, DC capacitor as energy storage, rectifier and voltage clamp circuit. This SSFG is designed to generate typical power disturbances, such as voltage sag/swell, over/under voltage and voltage flicker. Also it is designed to generate unexpected voltage phase jumping waveform by controlling the series inverter. In this paper, three kinds of control methods for the proposed 2MVA SSFG we investigated by PSIM simulation. Also typical voltage sag, swell, flicker waveforms are implemented by adopting effective control method.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.1
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• pp.385-392
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• 2013

A key element of the fog warning system to prevent large traffic accidents is a visibility measurement device. Recently, the need for it that is similar to the human visual sense and cheap and accurate than expensive fog sensors is increasing. In this paper, we present the performance evaluation and the economic analysis of the Road Visibility Measurement System (RVMS), which is developed for measuring the road visibility through a CCTV camera. For experiments, we have installed a CCTV camera, a fog sensor, and visibility signs at the Yeo-ju Test Road on the Central Inland Expressway. We evaluated the measurements from RVMS and the fog sensor based on observations. The result shows RVMS outperforms the fog sensor with respect to measurement stability and correctness. We also show RVMS has higher economic feasibility and various applications. RVMS can prevent the traffic accidents caused by severe fog and enhance the process of the wide-area visibility information system significantly.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.5
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• pp.19-24
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• 2019

The development of ICT technology has a huge impact on the existing closed CCTV security equipment market. With the importance of video data particularly highlighted in areas such as self-driving cars, unmanned vehicles and smart cities, various technologies using video are emerging. In this paper, we proposed a method to transmit videos and metadata as a part of smart city integration, and to solve the traffic, environment and security problems caused in urban life by utilizing the metadata instead of using CCTV videos for simple recording purposes, and reverse tunneling technique was designed and implemented as a method for accessing CCTV videos for vehicles from remote locations. Integrated management of CCTV videos and metadata for vehicles that have been used only for limited purposes in closed environments will enable efficient operation of integrated centers in real time required by smart cities, such as vehicle status check, road conditions and facility management.

• Journal of the Korean Mathematical Society
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• v.59 no.3
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• pp.571-594
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• 2022

Let D be an integral domain with quotient field K, Pic(D) be the ideal class group of D, and X be an indeterminate. A polynomial overring of D means a subring of K[X] containing D[X]. In this paper, we study almost Dedekind domains which are polynomial overrings of a principal ideal domain D, defined by the intersection of K[X] and rank-one discrete valuation rings with quotient field K(X), and their ideal class groups. Next, let ℤ be the ring of integers, ℚ be the field of rational numbers, and 𝔊f be the set of finitely generated abelian groups (up to isomorphism). As an application, among other things, we show that there exists an overring R of ℤ[X] such that (i) R is a Bezout domain, (ii) R∩ℚ[X] is an almost Dedekind domain, (iii) Pic(R∩ℚ[X]) = $\oplus_{G{\in}G_{f}}$ G, (iv) for each G ∈ 𝔊f, there is a multiplicative subset S of ℤ such that RS ∩ ℚ[X] is a Dedekind domain with Pic(RS ∩ ℚ[X]) = G, and (v) every invertible integral ideal I of R ∩ ℚ[X] can be written uniquely as I = XnQe11···Qekk for some integer n ≥ 0, maximal ideals Qi of R∩ℚ[X], and integers ei ≠ 0. We also completely characterize the almost Dedekind polynomial overrings of ℤ containing Int(ℤ).

• Journal of Chest Surgery
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• v.37 no.9
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• pp.742-748
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• 2004

The On-X valve was recently introduced. It was the aim of this study to assess the safety and feasibility from the data derived from 28 patients who underwent aortic and/or mitral valve replacement with this prosthesis in National Medical Center. Material and Method： From May 1999 and May 2003, a series of 28 consecutive patients who had been implanted with 32 On-X prosthesis were reviewed, The operative procedure comprised of 12 MVR, 10 AVR and 6 DVR. The study followed the guidelines of AATS/STS. Mean follow-up was 27 months (total 04 patient-years). Result: Early ($\leq$30 days) mortality was 7.44% (2/28) and no late mortality occurred in the study. Total actuarial freedom from mortality at 2 years was 92.86$\pm$4.87% for all cases, 100% for MVR, 90$\pm$9.49% for AVR, and 83.3$\pm$1.52% for DVR. Thromboembolic event occurred in 2 MVR patients and that was the only complication; therefore, the linearized incidence of valve related complications was 3.17%/ patient-years for all cases and 6.5%/patient-years for MVR and the actuarial freedom from valve related complications at 2 years was 84.85$\pm$10.75%. Preoperatively, 24 (85.71%) patients were in NYHA functional class III or IV but postoperatively, 25 (89,29%) patients were in NYHA functional class I or II. The levels of hemoglobin, hematocrit, serum LDH, reticulocyte rate and indirect bilirubin were all within normal range at postoperative 3 month. In mitral position, the peak gradient was 6.1$\pm$1.8 mmHg and the mean gradient was 3.0$\pm$0.6 mmHg and EOA were 2.54$\pm$0.56 $m^2$, 2.39$\pm$0.73 $m^2$, 2.34$\pm$0.55 $m^2$, 2.40$\pm$0.63 $m^2$ at 27 mm, 29 mm, 31 mm, 33 mm respectively. In aortic postion, the peak gradient was 21.1 $\pm$14.12 mmHg and the mean gradient was 12.3$\pm$6.52 mmHg. Conclusion: Since there was no significant difference in the postoperative mortality, valve related complications and echocardiographic hemodynamic data compared to standard bileaflet design and since there was an improvement in the NYHA functional class and normal values of hemolytic indicators, it can be assumed that On-X valve is safe and feasible. However, accumulation of cases and long-term follow-up of this patient group is needed to establish this result.