FPGA를 이용한 피에조 부하 구동용 고전압 단방향 인버터의 PI 및 히스테리시스 전압 제어 특성 비교

김기석,조용호,김형섭,강태삼,홍선기,Kim, Ki-Seok,Cho, Yong-Ho,Kim, Hyeong-Seop,Kang, Tae-Sam,Hong, Sun-Ki 대한전기학회 2017 전기학회논문지 Vol.66 No.1

In this paper, hysteresis voltage control method is proposed to an unidirectional inverter control for piezoelectric load. Piezoelectric load has electrically RC characteristic, and is driven by the inverter to control the output voltage waveform. When controling the output waveform by PI control, appropriate gains need to be selected. However, hysteresis control may minimize the output distortion because it has maximum proportional gain. In addition, Hysteresis control algorithm has simple structure to realize and the response is fast. Although the switching frequency of the inverter by hysteresis control varies, the switching frequency for the piezoelectric load is lower than that by PI control for equivalent performance. In particular, on implementing the algorithm using FPGA, the algorithm can be implemented in fewer pabrics and the processing time can be reduced. The superiority of the proposed hysteresis voltage control was proved for piezoelectric load through simulation and experiment.

한 가족 두 명에서 발견된 가족성 망막세동맥 만곡증

김기석,김인태,이원기,Ki-Seok Kim,In-Tae Kim,Won-Ki Lee 대한안과학회 2005 대한안과학회지 Vol.46 No.10

Purpose: To report two cases of familial retinal arteriolar tortuosity found in a 62-year-old female patient and her daughter. To our knowledge, this is the first time this familial condition has been observed in Korea. Methods: Retinal arteriolar tortuosity was observed in a 62-year-old female patient. For the differential diagnosis of retinal vascular tortuosity, we performed diverse laboratory tests and thorough history taking. Suspecting familial association, we performed a careful ocular examination on her 32-year-old daughter. Results: Similar patterns of retinal arteriolar tortuosity were observed in her daughter’s fundus, to a lesser degree. We diagnosed the female patient and her daughter with familial retinal arteriolar tortuosity. Conclusions: We present two cases of familial arteriolar tortuosity within one family. This is the first report of familial arteriolar tortuosity in Korea to our knowledge.

아키비스트의 양성, 어떻게 할 것인가?

김기석,Kim, Ki-Seok 한국기록학회 2000 기록학연구 Vol.0 No.1

This paper is propose for some guidelines in making curriculum for the training of archivists for Koran records. This paper pays special attention to the revival of the culture of record-keeping tradition of our owns. Without it's revival, a blind introduction of archival sciences based on Western civilizations can be ended up another version of cultural and academic imperialism as such in the field of the record-management of Korean records. Rapidly growing information and computer technology of our owns must be incorporated in the making of archivist training programs. It proposes that the opening of archival science major as a department at the graduate school level is in the long run essential, yet that of an associate master degree program can be in real an alternative. A training of archivists is not just to produce of a technician but a crafts(wo)man who would be in the vanguard of the renaissance of the record-keeping culture in Korea.

음성 인식 신경망을 위한 음성 파라키터들의 성능 비교

김기석,임은진,황희융,Kim, Ki-Seok,Im, Eun-Jin,Hwang, Hee-Yung 한국음향학회 1992 韓國音響學會誌 Vol.11 No.3

There have been many researches that uses neural network models for automatic speech recognition, but the main trend was finding the neural network models and learning rules appropriate to automatic speech recognition. However, the choice of the input speech parameter for the neural network as well as neural network model itself is a very important factor for the improvement of performance of the automatic speech recognition system using neural network. In this paper we select 6 speech parameters from surveys of the speech recognition papers which uses neural networks, and analyze the performance for the same data and the same neural network model. We use 8 sets of 9 Korean plosives and 18 sets of 8 Korean vowels. We use recurrent neural network and compare the performance of the 6 speech parameters while the number of nodes is constant. The delta cepstrum of linear predictive coefficients showed best result and the recognition rates are 95.1% for the vowels and 100.0% for plosives. 음성 인식에 신경망 모델을 적용하는 많은 연구들이 있었지만, 주된 관심은 음성인식에 적합한 구조와 학습 방법이었다. 그러나 음성인식에 신경망 모델을 적용한 시스템의 효율 향상은 모델 자체의 구조뿐 아니라, 신경망 모델의 입력으로 어떤 음성 파라미터를 사용하는가에 따라서도 큰 영향을 받는다. 본 논문은 기존 음성인식에 신경망 모델을 적용한 많은 연구들에서 사용한 음성 파라미터를 살펴보고, 대표적인 음성 파라미터 6개를 선정하여, 같은 데이타와 같은 신경망 모델 하에서 어떻게 성능이 달라지는지를 분석한다. 인식 실험에 있어서는 한국어 파열음 9개에 대한 8개 데이터 집합과 모음 8개에 대한 18개 데이터 집합을 음성 파라미터로 하고 신경망 모델은 순환 신경망 모델을 사용하여 노드의 수를 일정하게 한뒤 다양한 입력 파라미터의 성능을 비교하였다. 그 결과 선형 예측 계수로부터 얻어진 delta cepstrum의 음성 파라미터가 가장 좋은 성능을 보였으며 이때 인식률은 같은 학습 데이터에 대해 파열음 100.0%, 모음 95.1%이었다.

아연 - 티타늄 복합산화물 탈황제의 제조 및 반응특성 연구

김기석,박노국,이태진 ( Ki Seok Kim,No Kuk Park,Tae Jin Lee ) 한국공업화학회 1997 공업화학 Vol.8 No.1

아연-티타늄 복합금속산화물 탈황제를 제조하여 석탄가스중의 H₂S를 제거하는 고온탈황성능을 연구하였다. H₂S 흡수에 의한 탈황제의 황화반응실험을 충전충 관형 흐름반응기를 사용하여 550∼750℃ 범위에서 수행한 결과 탈황율과 아연성분의 손실측면에서 650℃가 최적 황화반응 온도임이 밝혀졌다. SEM 분석에 의해서 650℃에서의 황화반응과 750℃에서의 재생반응에 따른 탈황제 입자의 구조변화를 관찰하였다. 탈황성능의 지속성과 탈황제 내구성을 평가하기 위하여 연속적인 황화-재생 cycle 반응실험을 수행하였으며 10번째 cycle 이후에 수거한 탈황제 시료의 특성을 BET, XRD, SEM/EDX에 의해서 분석하였다. 아연-티타늄 복합 산화물 탈황제는 연속적인 황화-재생 cycle 동안에 거의 일정한 탈황성능을 나타내었다. Zinc titanate sorbents for H₂S removal were prepared and their reactivities were studied for high temperature desulfurization of coal gas. Sulfidation of zinc titanates by H₂S sorption was conducted in a packed-bed tubular flow reactor at the temperature range of 550∼750℃, and the results reveal that 650℃ was the optimal sulfidation temperature with respect to desulfurization efficiency and zinc loss. The structural change of sorbent particle was investigated by SEM analysis for the sorbents sulfided at 650℃ and subsequently regenerated at 750℃. The stability of desulfurization capability as well as the mechanical stability of the zinc titanates was studied by means of the successive cycles of sulfidation-regeneration of sorbents, and the sorbent samples taken after the 10th cycle were characterized using BET, XRD, and SEM/EDX analyses. Zinc titanate sorbents exhibited nearly constant desulfurization capability in the successive cycle operation.

작품노트 - 사라져 버린 '달의 교회'와 '별의 교회'

김기석,Kim, Ki-Seok 대한건축사협회 1995 建築士 Vol.1995 No.3

알루미늄 廢드로스를 活用한 세라믹 多孔體의 製造

김기석,박제현,박재구,Kim, Ki-Seok,Park, Jay-Hyun,Park, Jai-Koo 한국자원리싸이클링학회 2005 資源 리싸이클링 Vol.14 No.2

알루미늄 폐드로스를 이용한 다공성 경량세라믹의 제조조건을 제시함으로서 폐드로스의 요업용 원료로서의 재활용가능성을 살펴보았다. 알루미늄 폐드로스의 전처리 과정으로 4~7번의 수세와 900$^{\circ}%의 배소를 수행하여 수세와 배소 특성을 살펴보았다. 배소 후 드로스는 XRD분석에 의해 스피넬상이 형성되었다. 배소된 폐드로스는 슬러리 상태로 분쇄되었다. 분쇄시 슬러리의 분산성을 확보하여 고농도의 슬러리를 제조하기 위해 분산조제 첨가량에 따른 분산특성을 살펴보았다. 다공체는 슬러리 발포법을 사용하여 제조되었다. 발포조제로 계면활성제가 첨가되었으며 상온에서 자기체적의 2-3배로 발포된 후 성형-건조되었다. 3배 발포시켜 제조된 다공체는 기공율이 약 84%, bulk 밀도는 약 0.59 g/cm$^3$로 측정되었고, 50~500 ${\mu}m$ 크기범위의 기공들이 형성되었다. 화상해석결과 다공체 표면의 평균기공크기는 약 200 ${\mu}m$ 였다. 알루미늄 폐드로스 성형체는 1150$^{\circ}C-1250$^{\circ}C에서 소결되었으며, SEM관찰결과 1200$^{\circ}C에서 소결특성이 양호한 것으로 나타났다. The recycling possibility of aluminum waste dross(AWD) as a ceramic raw material of porous light-weight material was examined. A aluminum waste dross was washed 4-7 consecutive times and roasted at 900$^{\circ}% for 1hour as pre-treatments. The properties of the pre-treatment of aluminum waste dross was investigated. It was conformed by XRD result that the spinel crystalline was grown in AWD, after roasting. After the roasted AWD was ground in aqueous state, the sodium hexaphosphate(SHP) as a dispersant which is used for stabilizing the concentrated slurry was added to the AWD slurry. The porous material was prepared by slurry foaming method with surfactant at room temperature. The foamed slurry volumes were 2 and 3 times of the original slurry volume. The properties of porous material with extended volume of 3 times was following: the porosity was about 84%, bulk density was 0.59 g/cm$^3$, the range of pore was from 50 ${\mu}m$ to 500 ${\mu}m$ and mean pore size was about 200 ${\mu}m$. AWD porous material was sintered at 1150$^{\circ}C-1250$^{\circ}C. It was colcluded that AWD was sintered well at 1200$^{\circ}C from material surface observation by SEM.

도약로봇을 위한 도약 각도-높이 조절 메커니즘

김기석(Ki-Seok Kim),김병상(Byeong-Sang Kim),송재복(Jae-Bok Song),김은석(Eun-Seok Kim) 대한기계학회 2008 대한기계학회 춘추학술대회 Vol.2008 No.5

It is desirable that the guard robot should be small-sized and light-weighted to increase its portability. In addition, it should be able to overcome a relatively high obstacle to cope with different situations. The jumping robot can reach a higher place more rapidly than other locomotion methods. There are several ways to provide the jumping ability and the use of the elastic energy of a spring is one of the best ways to make the robot compact and lightweight. This paper proposes the jumping robot capable of independent control of the jumping angle and height. The adjustable jumping angle-height mechanism based on the screw-nut mechanism was developed. The validity of the mechanism was verified by various experiments. It is shown that the robot using this mechanism can provide good jumping ability in the rough terrain.

임상연구 : Propofol을 이용한 마취 유도 후 근이완제 투여 없는 기관내 삽관 시의 Remifentanil의 적정 용량

김기석 ( Ki Seok Kim ),김범진 ( Bum Jin Kim ),이상석 ( Sang Seok Lee ),유병훈 ( Byung Hoon You ),우승훈 ( Seung Hoon Woo ),홍기혁 ( Ki Hyuk Hong ),이윤석 ( Yoon Suk Lee ) 대한마취과학회 2006 Korean Journal of Anesthesiology Vol.51 No.4

Background: Many studies have shown that tracheal intubation could be facilitated after induction with propofol and opioids without muscle relaxants. Remifentanil, which has a rapid onset and ultra-short duration of action, is a useful estrase-metabolized opioid (EMO) for tracheal intubation. This study was designed to evaluate the adequate induction dose of remifentanil with propofol 1.5 mg/kg for tracheal intubation without muscle relaxants. Methods: We have assessed intubating conditions in five groups of 57 female patients, ASA PS I or II. Each group was administerd intravenous propofol 1.5 mg/kg with remifentanil 1.0μg/kg, 2.0μg/kg, 3.0μg/kg, 4.0μg/kg and 5.0μg/kg, respectively. Intubation was attempted, and the intubating condition was scored by the degrees of relaxation of jaw (0-2), position of vocal cords (0-2) and the patient response (0-2). Mean arterial pressure (MAP) and heart rate (HR) were observed at each group. Results: The relationship between the concentration of remifentanil and the possibility of endotracheal intubation was as following: Probit (P) = - 1.38 (S.E.: 0.58) + 0.087 (S.E.: 0.23) × DRemi. The ED50 of remifentanil for endotracheal intubation without muscle relaxants was 2.12 (95% confidence interval: 1.42-2.62) μg/kg and the ED95 was 4.01 (95% confidence interval: 3.31-5.92) μg/kg. Conclusions: We concluded that adequate dose of remifentanil which make possible to endotracheal intubation without muscle relaxants after induction of general anesthesia with 1.5 mg/kg of propofol is 4.01μg/kg in 95% of female patients and 2.12μg/kg in 50% of female patients. (Korean J Anesthesiol 2006; 51: 405~10)

FPGA를 이용한 진보형 히스테리시스의 전류 제어 연구

김기석(Ki seok Kim),이정섭(Jung Sub Lee),홍선기(Sun-Ki Hong) 대한전기학회 2014 대한전기학회 학술대회 논문집 Vol.2014 No.7