Adaptive Maximum Power Point Tracking Algorithm for Photovoltaic Power Systems

AHN, Chang Wook,CHOI, Ju Yeop,LEE, Dong-Ha,AN, Jinung The Institute of Electronics, Information and Comm 2010 IEICE TRANSACTIONS ON COMMUNICATIONS - Vol.93 No.5

<P>This paper presents an adaptive maximum power point tracking (MPPT) algorithm. The aim is to dynamically adjust the step length for updating duty ratio (or operating voltage) so as to make full utilization of the output power of photovoltaic (PV) systems, even under the rapidly changing atmospheric conditions. To this end, the average slope in terms of voltage and power is exploited for reducing the harmful effect of noise and error (incurred in measurement or quantization) on the slope. Also, a statistical decision-making scheme is employed for reliably deciding the time instant at which atmospheric conditions actually change. Empirical study has adduced grounds for its dominance over existing references.</P>

흉부 X선촬영 기술의 변천에 관한 연구

이창엽,조평곤,김지닐,최소영,김창균,최종학,김정민,김유현 高麗大學校 倂設 保健大學 保健科學硏究所 2002 保健科學論集 Vol.28 No.2

To find elements which enable improving Quality of image of chest radiography, we attempted to make comparison between chest radiography used currently with that of the past, and following conclusion was reached: 1) It could be confirmed that a dependance on chest radiography was declining, because proportion of chest radiography against overall radiography decreased. 2) There was a change of kVp to a high voltage in a chest radiography, and use of high kVp became a generalization 3) Exposure time was reduced and exposure dose was curtailed accordingly. 4) Apparatus was mainly comprised of 3-phase rectifier circuit and inverter type. 5) It could be confirmed that frequency of applying additional filters for high kVp radiography was insufficient. 6) There was almost no difference in the condition of exposure between hospitals using film/screen and hospitals using CR. But when CR is used for radiography, it was increase in exposure dose due to increase in tube current and it will be necessary to have continuous study on exposure dose by an increase use of CR in the future.

인덕터의 DC 바이어스 특성을 고려한 대용량 DC-DC 컨버터의 손실계산

조영창(Young-Chang Jo),최주엽(Ju-Yeop Choi),정승기(Seung-Ki Jung),최익(Ick Choy),송승호(Seung-Ho Song) 대한전기학회 2011 전기학회논문지 Vol.60 No.4

It is necessary to accurately predict converter losses for optimized design of a high-power DC-DC converter. The losses of switching devices and inductor among the elements of the converter take significantly greater proportion. The current ripple will be determined by the size of the inductance and this inductance value varies depending on the DC amount of inductor current. As the inductance changes according to load current, the change influences not only the inductor loss itself but also the total converter loss. In this paper, for more accurate design of a bi-directional DC-DC converter for 30㎾-class energy storage system, more accurate computational model is proposed considering inductance variation according to the load current change. The inductance changes using variable magnetic cores are verified and converter efficiency is tested through simulations and experiments.

의도적인 견갑골 외전이 Sit-and-Reach Test에 미치는 영향

김선엽,지창연,김광수 대한정형물리치료학회 2000 대한정형도수물리치료학회지 Vol.6 No.1

Purpose : This study was done to examine the actual effect of the scapular position in these flexibility tests. The purpose of this study was to examine the differences between the measurement of SRT(Sit-and-Reach Test) without intentional abduction of the scapular (pre-test) and with intentional abduction of the scapular (post-test). The hypothesis is: 1. There is no differences in the SRT result of the pre-test and the post-test. 2. There is no differences in the HJA(Hip Joint Angle) result of the pre-test and the post-test. 3. There is no differences in the Spine Motion Test(SMT) result of the pre-test and the post-test. Method : The total 60 people (30 men, 30 women) were participated in this study. In the pre-test, the subjects were asked to sit on the examination table and try the SRT motion: and then the HJA, SRT and the SMT numerical values were taken. In the post-test, the subjects were instructed to intentionally bring the scapula outward from the midline: and the HJA, SRT and the SMT numerical values were taken. Result : In the pre-test, the SRT result averaged 34.17cm, and in the post-test, the SRT result averaged 36.68cm. The difference was about 2.81cm which showed a significant mean statistically (p<0.01). The measurement increased by 8.22%. The HJA was 85.9˚ in pre-test, and it was 85.5˚ in post-test, giving the 0.4˚ differences. Therefore, it didn't have a statistical mean (p>0.05). The SMT value was 69.28cm in the post-test, about 0.28cm decreased. Therefore, it didn't have a statistical mean(p>0.05). SRT values and HJA values were correlated (p<0.01). SMT values and SRT values (p<0.01), and SMT values and HJA values (p>0.05) were each in counter correlation. Conclusion : The result of the SRT without intentional scapular abduction (34.17cm) and with intentional scapular abduction (36.68cm) showed a significant increase about 8.22% (p<0.01). In SRT, the effect of the intentional scapular abduction on SMT showed no significant means, the pre-test value being 69.59cm and the post-test value being 69.28cm (p>0.05).

MgO-Al₂O₃-SiO₂계 요업원료(Mullite,Spinel,Cordierite)의 제조 및 소결특성 : Ⅰ. 알콕사이드 졸ㆍ겔법에 의한 물라이트 미분말의 합성 Ⅰ. Preparation of Mullite Fine Powder by an Alkoxide Sol-Gel Process

이홍림,신승엽,김창은 연세대학교 산업기술연구소 1987 논문집 Vol.19 No.2

Mullite fine powder was prepared from alkoxides and its powder characterization was examined. The average particle size of mullite powder which was prepared at 1300℃, for 3 h was 0.1-0.2㎛ and the surface area was 11.2㎡/g by BET measurement.

만성 요통환자의 복부 심부근과 표재근을 중심으로 한 운동 효과 비교

김진산,이창현,조미주,임연욱,정취산,김선엽 대한정형도수치료학회 2005 대한정형도수물리치료학회지 Vol.11 No.1

Objectives: To compare the efficacy of two types specific exercise intervention (deep and superficial abdominal muscle exercises) in the treatment of patients with chronic low back pain (CLBP). Design: A randomized, comparative, repeated-measures. Subjects: Twenty-four patients with CLBP (at least for 3 months), mean age±SD=51.58±16.21 (yrs). Methods: Twenty-four patients with this condition were assigned randomly to two treatment groups. Both first and second group underwent 3 weeks specific exercise treatment program. The first group specific trained for the deep abdominal muscles. The second group specific trained for the superficial abdominal muscles. Results: After intervention, the first group showed a statistically significant reduction in pain intensity and functional disability levels (p<.05). The second group showed no significant change in these parameters after intervention (p>.05). Conclusions: According to results, a "deep abdominal muscle exercises" treatment approach appears more effective than a "superficial abdominal muscle exercises" treatment in patients with CLBP.

슬개골 골절에서 관절경을 이용한 정복 및 내 고정술

고상훈,조성도,나화엽,김우석,정유영,곽창렬,김범수 대한골절학회 2003 대한골절학회지 Vol.16 No.4

탈지작업 근로자의 트리클로로에틸렌 폭로에 관한 조사

박두용,김형아,김창엽,백남원,조정진,김양호,이광묵 가톨릭대학 산업의학 쎈타 산업의학연구소 1989 韓國의 産業醫學 Vol.28 No.4

Trichloroethylene(TCE) is a widely used organic solvent, especially in degreasing process of metal manufacturing, however few data concerning its exposure and poisoning were obt-ainable. This survey was performed for more information of TCE exposure in this country. Urine sanmples were collected from 144 TCE handling workers and 46 non-TCE-exposed workers. TCE concentrations of four workshops in working environment were analyzed. The results were as follows; 1. TCE exposed workers were 48 male and 96 female employees. Average total duration of employment of these workers was 39.0 months, average duration of works per day was 10.7 hours, and average duation of TCE handling was 469.7 minutes. 2. The average concentration of urine total trichloro-compounds was 156.32㎎/ g crea-tinine, and that of trichloroacetic acid was 69.2㎎/g creatinine. Of those workers, 78 workers had the concentrations of urine trichloroacetic acid over 75㎎/g, which is the biological exposure index (BEI) of urine trichloroaxetic acid in Korea. Duration of work per day and duration of TCE- related work were significantly longer in the group of workers whose urine trichloroacetic acid concentration was over the criteria level of BEI. 3. TCE concentrations of three workshops were over the level of ACGIH TLV(threshold limit value), 50ppm in TWA (time -weighted average). In remaining one workshop, duration of TCE related works was only one hour per day. There was statistically significant correl-ation between the concentration of TCE in working environment and the proportion of workers in a workshop whose urinary trichloroacetic acid concentration was over the criteria level of BEI. 4. Responses to self-administered questionnaire were not meaningful for differentiation of psychoneurologica symptoms due to chronic TCE exposure from othres.

Isolation and Identification of a Lactic Acid Bacterial Strain KJ-108 and Its Capability for Deodorizing Malodorous Gases Under Anaerobic Culture Conditions

( Jeong Dong Kim ),( Jung Hoon Yoon ),( Yong Ha Park ),( Dae Weon Lee ),( Kyou Seung Lee ),( Chang Hyun Choi ),( Won Yeop Park ),( Kook Hee Kang ) 한국미생물생명공학회 2003 Journal of microbiology and biotechnology Vol.13 No.2

中西部地域 百濟漢城期 木棺墓 變化 - 烏山 水淸洞遺蹟을 中心으로

이창엽(Lee Chang-Yeop) 한국고대학회 2007 先史와 古代 Vol.27 No.-

서울과 경기남부, 충청지역에서 확인되는 원저단경호와 심발형토기가 조합되어 부장된 토광묘, 주구토광묘는 중서부지역 분묘 연구에 있어서 선구적인 역할을 담당했던 천안 청당동유적의 연대관에 근거하여 원삼국시대 대표적인 분묘로 인식되고 있다. 그런데 청당동유적의 연대는 당시 자료가 부족한 상황에서 부산 노포동유적과 같은 일부 영남지역 분묘와의 교차연대에 따라 설정된 것으로 이후 많은 자료가 축적되어 재고할 여건이 마련되어 가고 있다고 판단된다. 이에 본고에서는 중서부지역 원저단경호 출토 분묘에 대해 나름의 연대와 변화상을 제시하고자 하였다. 이를 위해 오산수청동유적을 중심으로 분묘의 구조와 유물조합상의 특징을 간략히 살펴보고, 소문단경호와 심발형토기의 형식분류를 중심으로 단계를 설정하였다. 이를 기반으로 교차편년을 행하고 그에 따른 중서부지역에 있어서 목관묘의 변화를 살폈다. 그 결과 기존에 원삼국시대에서 삼국시대 전기에 해당된다고 설정되었던 유물부장부를 가지는 토광묘는 목관묘이고, 그 연대는 3세기말 이후로 편년됨을 확인하였다. 백제의 중심으로 생각되는 서울지역에서의 유례가 없어 명확하지는 않으나, 서울을 제외한 경기 남부와 충청 북부 일대에 있어서는 대동소이한 흐름을 가지는 것으로 보아 서울 역시 예외는 아니었으리라 생각된다. 따라서 이 분묘들이 삼국시대 백제한성기 이른시기의 대표적인 분묘로 생각해도 좋을 것이다. 기존에 4세기대로 편년되어 한성기의 분묘로 생각되었던 백제토기가 출토되는 석촌동 분묘군은 백제토기의 편년 검토를 통해 그 연대는 재고되어야 할 것으로 생각된다. The pit tomb and the pit tomb with ditch in which buried together with combination of short necked round bottom jars and the deep bowl shaped potteries which have been discovered in Seoul as well as in the southern Gyeonggi and Chungcheong region are recognized as the prevailing forms of tomb representing the Proto-Three Kingdoms period based on the chronology of Cheonan Cheongdang-dong remains that has taken a trailblazing role in the research on tombs in mid-west region. However, it should be noted that the chronology of Cheongdang-dong remains had been established according to cross-dating in connection with the tombs found in some part of Yeongnam region, like Busan Nopodong remains, under a situation of lacking data and materials. Since then after, many data and resources have been cumulated, so then it is judged that conditions have been improved so much as to be able to reconsider the chronology thereof. In this research paper, researcher tried to present the chronology and the status of changes with regard to the tombs located in the mid-west region from which short necked round bottom jars were excavated. To do this, the distinctive features of structures of the tomb and of the status of relic combinations were briefly reviewed, and then the phases of change were established with a focus on the classification of type of short necked jar without a paddle pattern and the deep bowl shaped pottery. Cross dating was done based on these works, and according to this chronology, changes in wooden coffin tomb were investigated. As the results, it was confirmed that the pit tomb having the part of the interment of belonging with corpse, of which chronology was so regarded as to fall into the period, ranging from the Proto-Three Kingdoms period to the early Three Kingdoms period, was wooden coffin tomb, and that it was then chronologized after the end of third century. Though it is not so clear, for there were no examples found in Seoul region, which is considered the center of Baekje, it is thought that Seoul would have not been excepted, when judging it based on the fact that there are more or less same trend of the tomb in the southern Gyeonggi and a part of the northern Chungcheong, except Seoul. Therefore, it will be ok if these tombs are considered the tombs representing the early Baekje Hanseong Period. And it is thought that chronology of the group of tombs in Seokchon-dong where Baekje potteries have been excavated and which were regarded as the tombs from the Baekje Hanseong Period, for it was already chronologized as in four century should be reconsidered.