• Proceedings of the KIPE Conference
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• 2013.07a
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• pp.161-162
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• 2013

LED(Light Emitting Diode)는 친환경적 특성, 긴 수명, 우수한 효율, 빠른 응답 속도 등의 장점이 있어 최근 기존의 백열 전등 및 형광등을 대체하는 조명 수단으로 각광받고 있다. 기존의 LED구동회로를 조광기용 MR16안정기에 연결할 경우 안정기와 조광기의 오동작으로 인해 Flicker 현상이 발생되고 선형적인 Dimming이 불가능하다. 그러므로 본 논문에서는 MR16 안정기와 조광기용 MR16안정기를 호환하는 Flicker Free LED 구동회로를 제안한다. 또한 LED구동회로의 원리와 Dimming에 따른 LED전류제어기법 원리를 설명하고 모의실험 및 시작품 제작을 통해 제안 회로의 타당성을 검증한다.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2019.05a
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• pp.201-202
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• 2019

The high performace water reducing agent with three-hours-fluidity-retention performance is developed for the purpose of entering into the global market belonging to extreme environment such as Southeast Asia and the Middle East. In this study, the fresh and mechanical properties of the high strength concrete with three-hours-fluidity-retention performance are evaluated by making mock-up members in Vietnam.

• Proceedings of the Korea Information Processing Society Conference
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• 2019.10a
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• pp.249-252
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• 2019

본 논문은 파충류 시장의 활성화와 파충류 사육 부담감을 해소하고자 사육자들에게 편리하고 접근성이 높은 서비스를 제공하는 파충류 사육을 위한 스마트 환경제어시스템을 제공한다. 본 논문이 제시하는 주요한 기능은 다음과 같다. 첫째, 사육장 내 습도를 미스팅 시스템과 팬을 통해 제어를 한다. 둘째, 사육장 내 온도를 조광기를 활용한 스팟 램프의 밝기 조절을 통해 제어한다. 셋째, 파충류 먹이 공급 및 물 공급을 자동화하여 체계적인 식단을 관리한다. 넷째, 적외선 감지 센서를 통한 데이터를 활용해 파충류의 활동량과 탈피 및 질병의 가능성을 예상한다. 제안된 시스템은 IoT 기술을 접목함으로써 현대 사회에서 추구하는 편리함과 기존 파충류 사육의 번거로움을 해소하는 것을 목표로 한다.

• Korean Journal of Optics and Photonics
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• v.30 no.4
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• pp.146-153
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• 2019

The exposure system is a device that transfers a circuit pattern to a desired location. To display patterns on a substrate without deforming the optical characteristics, the characteristics of the optical exposure system are very important. Therefore, to form a microcircuit pattern, a small divergence angle should impinge on the irradiation area. Also, since the light from the source must react uniformly with the photosensitizer, it must have high luminance efficiency and uniformity of illumination. In this paper a parabolic reflector and an aspherical lens were designed to solve the problem of narrow-angle implementation, and it was confirmed by simulation analysis after their arrangement that the beam angle, uniformity, and maximum illuminance satisfied the target performance.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.27 no.2
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• pp.84-94
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• 2013

In case when the existing TRIAC phase controlled dimmer is drove for the LED lighting equipments, there are many problems such as the LED flicker in low phase-angles, the acoustic noise and elements damage by increase of the peak voltage in the input filter capacitor, mulfunction by insufficiency of the TRIAC holding current, and the abnormal oscillation by LC resonant. In this paper, we proposes the single-stage quasi-resonant PSR(Primary Side Regulation) PWM converter, and the design, the simulation and experiment are performed. As a result, it could confirm that the proposed PWM converter is the lighting equipments for LED drive which can alternate the existing 60W class incandescent bulbs and it has the high drive performance of the efficiency 80% and over, the power factor 0.95 and over under the normal voltage 220V. Finally, total harmonic distortion(THD) is gratified with a standard[1] of the lighting equipments and the durability is evaluated as the high reliablilty of 150,000 hours and over.

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.373-373
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• 2023

기후변화로 인한 홍수재해는 우리나라를 포함한 모든 전세계의 이슈로 우리 앞에 다가와 있다. 수자원 인프라가 잘 구축된 우리나라와 달리 저개발국가로써 관련 인프라가 미흡한 국가의 경우대규모 예산 투입이 필요한 댐, 제방 등의 수자원 인프라 시설보다는 비구조적대책인 홍수예경보시스템 구축을 통해 재해취약지역내 우선적으로 도입하는 유역단위 비구조적인 홍수관리계획이 필요하다(김광기, 2022). 본 연구에서는 2012년 금강권역을 대상으로 구축된 홍수예측모형에 대한 개선을 위해 최신 하도자료와 시설물 현황 자료를 반영하여 수리학적 모형을 신규 구축하였다. 이를 위한 수리학적 홍수추적 모형은 FLDWAV 모형을 사용하였으며, 모형의 대상구간은 금강 상류에 위치한 용담댐에서부터 대청댐 구간까지 189.32 km 구간을 선정하였다. 대상구간은 총 773개의 하도단면으로 구성하여 대상하천에 대한 지형변화를 최대한 반영하고자 하였으며, 홍수사상은 유량이 많은 홍수사상뿐만 아니라 저유량에서도 모형의 정확도를 확보하기 위해 다양한 사상을 선정하여 보정과 검증을 실시하였다. 본 연구에서 구축된 금강의 용담댐에서 대청댐 구간에 대한 수리학적 해석모형은 다양한 홍수사상을 대상으로 모형에 대한 보정과 검증을 실시함으로써 보다 정확도 높은 홍수예경보시스템을 구축하여 하천 재해 발생을 예방하는데 활용할 수 있을 것으로 기대한다.

• Journal of Conservation Science
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• v.26 no.2
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• pp.171-182
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• 2010

The slag excavated from Gyesil-ri in Gongju, Yeonje-ri in Cheongwon and Beopcheonsaji (temple) site in Wonju are analyzed by X-ray Fluorescence Analyzer, metallurgical microscope, SEM-EDS etc., for chemical composition and microstructure to figure out the raw material and the iron manufacturing technique. First of all, as a result of principal component analysis, the total Fe-content of slag from Gyesil-ri is 39 to 44% and the modified rate is 15 to 21%, which is common in ancient iron slag. Yeonje-ri site is found the ancient iron-smelting furnace. The total Fe-content of slag from Yeonje-ri is 41 to 43% and modified rate is 18~30%, which is also the general value in the ancient slag. However only slag is excavated in the residential area at Beopcheonsaji site and there is no iron making relic. In addition, the result of principal component analysis contains that the total Fe-content of Beopcheonsaji site is 52 to 57%, and modified rate is 8 to 14%. It shows that the total Fe-content of Beopcheonsaji site is higher than relic from Gyesil-ri and Yeonje-ri and the modified rate is lower than other sites. This results mean that recollecting rate of Fe in Beopcheonsaji site is lower than other sites. Also, as a result of minor elements analysis, the slag from Gyesil-ri has the higher level of Ti, V and Zr than other sites and the microstructure are observed as magnetite and ulvospinel, so that the raw material of slag is iron sand. But the slag from Yeonje-ri and Beopcheonsaji site are identified to use iron ore. As a result of microstructure observation, fayalite, gray-columnar crystal, is found in the slag from Yeonje-ri and big wustite as main phase is observed in the slag from Beopcheonsaji site. This study show that the slag from Yeonje-ri is made of smelt ash produced during smelting works and the slag from Beopcheonsaji site is made of forging ash produced during forging work concerning the excavated location and the microstructure.

• Journal of Bio-Environment Control
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• v.6 no.4
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• pp.292-298
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• 1997

These studies were conducted to verify the effect of the supplementary lighting by reflective film mulching and its establishment in the north side of greenhouse on the utility of light at tomato by means of investigating changes of leaf temperatures, stomatal features, transpiration rates and photosynthetic rates. Stomatal density of leaves were high in the reflective film mulching but sizes of stomata were not different. As the osmotic potential in rooting zone was low, the stomatal resistance was high, transpiration rate was low, and leaf temperature was increased by 40.62$^{\circ}C$. And also in the block of reflective film mulching photosynthetic rates were decreased hut chlorophyll contents were not different. Especially, there is an effect of controlling greenhouse whiteflies by treatment of reflective film mulching. It is thought that the reason of high quality or increasing yield at several crops by supplementary lighting, such as reflective film mulching, would be caused by influences of absorption and distribution of nutrients through high transpiration rate and photosynthesis which resulted from increase of stomata.

• Journal of the Korea Organic Resources Recycling Association
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• v.16 no.4
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• pp.57-63
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• 2008

The characteristics of the bio-oil produced by the pyrolysis process with pig feces was investigated in this paper. The continuous auger-type reactor produced bio-oil was maintained at the temperature range of 400 to $600^{\circ}C$, which was higher than a typical that in a conventional pyrolysis system. The pig feces was used as the feedstock. The bio-oil and its compositions were characterized by water analysis, heating values, elemental analysis, bio-oil compounds, by Gas Chromatography/Mass Spectrometry (GC/MS), and functional group by $^1H$ NMR spectroscopy. It was found that the maximum bio-oil yields of 21% w.t. was achieved at $550^{\circ}C$. This result suggested that this auger reactor might be a potential technology for livestock waste treatment to produce bio-oil because it is able to be improved to reach higher efficiency of bio-oil production in further study. The pyrolysis system reported herein had low heat transfer into the feedstock in the auger reactor so that it needs improve the heat conduction rate of the system in further study.

• Korean Business Review
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• v.11
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• pp.1-14
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• 1998

In this paper the negotiation skills, which have been so far known as non-scientific or artistic field, are analyzed on the basis of behavioral science view point. Negotiator's behavior and psychological situation are believed to influence the negotiation result significantly, therefore, those factors are reviewed with behavioral science framework. Some concepts developed in Cognitive Psychology to explain the decision making models - prominence, commitment, escalation of commitment, framing, adjustment and anchoring, endowment effect - are reconceptualized and applied to the negotiation skill analysis and negotiation skill development in this paper. As the results of this research, various negotiation skills which have been so far believed as irrational and artistic are now able to be explained on the basis of sound logic and reasoning. This means also that valuable and elegant negotiation skills should be further developed by behavioral scientists.