• 조명전기설비학회논문지
• /
• 제28권8호
• /
• pp.24-31
• /
• 2014

This paper dealt with the LED optical illumination system design for the Masthead navigation light to replace halogen lamps. We made Fresnel lens satisfy luminous intensity distribution of "Convention on the International Regulation for Preventing Collisions at Sea(COLREG)". The optical system is designed by classifying three parts: light source, lens, and cut off plate. The source of light has been made to have the uniform horizontal and vertical light distribution by placing 6 LEDs at intervals of $54^{\circ}$, and as the cylindrical Fresnel lens, the lens has been designed to achieve the uniform horizontal and vertical light distribution in the range of plain light. Finally, the cover has been designed to block the light from the outside of plain light and ultimately met the standards for light distribution of navigation lights. In addition, the validity of design has been verified with manufacturing a trial product.

• 한국경영과학회:학술대회논문집
• /
• 대한산업공학회/한국경영과학회 2006년도 춘계공동학술대회 논문집
• /
• pp.17-24
• /
• 2006

We consider the sensor location problem (SLP) on a given sensor field. We present the sensor field as grid of points. There are several types of sensors which have different detection ranges and costs. If a sensor is placed in some point, the points inside of its detection range can be covered. The coverage ratio decreases with distance. The problem we consider in this thesis is called multiple-type differential coverage sensor location problem (MDSLP). MDSLP is more realistic than SLP. The coverage quantities of points are different with their distance form sensor location in MDSLP. The objective of MDSLP is to minimize total sensor costs while covering every sensor field. This problem is known as NP-hard. We propose a new integer programming formulation of the problem. In comparison with the previous models, the new model has a smaller number of constraints and variables. This problem has symmetric structure in its solutions. This group is used for pruning in the branch-and-bound tree. We solved this problem by branch-and-cut(B&C) approach. We tested our algorithm on about 60 instances with varying sizes.

• Nuclear Engineering and Technology
• /
• 제49권8호
• /
• pp.1600-1609
• /
• 2017

The accelerator-driven subcritical system (ADS) is driven by a neutron source from spallation reactions introduced by the injected proton beam. Part of the neutron source has energy as high as a few hundred MeV to a few GeV. The effects of high-energy source neutrons ($E_n$ > 20 MeV) are usually approximated by energy cut-off treatment in practical core calculations, which can overestimate the predicted proton beam current in the ADS design. This article intends to quantize this effect and propose a way to solve this problem. To evaluate the effects of high-energy neutrons in the subcritical core, two models are established aiming to cover the features of current experimental facilities and industrial-scale ADS in the future. The results show that high-energy neutrons with $E_n$ > 20 MeV are of small fraction (2.6%) in the neutron source, but their contribution to the source efficiency is about 23% for the large scale ADS. Based on this, a neutron source efficiency correction factor is proposed. Tests show that the new correction method works well in the ADS calculation. This method can effectively improve the accuracy of the prediction of the proton beam current.

• Nuclear Engineering and Technology
• /
• 제50권8호
• /
• pp.1246-1254
• /
• 2018

The importance of performing Level 3 probabilistic safety assessments (PSA) along with a general interest in assessing multi-unit risk has been sharply increasing after the Fukushima Daiichi nuclear power plant (NPP) accident. However, relatively few studies on multi-unit Level 3 PSA have been performed to date, reflecting limited scenarios of multi-unit accidents with higher priority. The major difficulty to carry out a multi-unit Level 3 PSA lies in the exponentially increasing number of multi-unit accident combinations, as different source terms can be released from each NPP unit; indeed, building consequence models for the astronomical number of accident scenarios is simply impractical. In this study, a new approach has been developed that employs the look-up table method to cover every multi-unit accident scenario. Consequence results for each scenario can be found on the table, established with a practical amount of effort, and can be matched to the frequency of the scenario. Preliminary application to a six-unit NPP site was carried out, where it was found that the difference between full-coverage and cut-off cases could be considerably high and therefore influence the total risk. Additional studies should be performed to fine tune the details and overcome the limitations of the approach.

• Tribology and Lubricants
• /
• 제29권3호
• /
• pp.180-185
• /
• 2013

The purpose of this study was to analyze the tribological characteristics of the Electronic control suspension System in a car. In the first example, the cilp used to attach the front electronic control suspension(ECS) system's control actuator was fastened very tightly. Thus, the wire was cut because of continual rotation of the shock-up shover piston rod used to adjust the height of the car. This verified the disconnection phenomenon where wire damaged makes it impossible for the ECS system to send signal to the actuator. The second example, involved a minute hole that allowed gas to leak from the ECS system. As a result, the height of the car verified the down phenomenon. In the third example, the resistance of a wire measured at $0.21{\Omega}$, when the G sensor was disconnected from the system. This verified the system shutdown and lighting of the ECS warning lamp because of body interference caused by a slight pressure on the battery cover. Therefore, quality control is always necessary to ensure safety and durability of a car.

• 한국구조물진단유지관리공학회 논문집
• /
• 제6권2호
• /
• pp.255-261
• /
• 2002

Concrete structures stand in poor surrounding than it has ever been met before, because they are installed in severe conditions such as chloride penetration. $CO_2$ gas, water and so on. Therefore, the countermeasure to efficiently protect from the deterioration of concrete structures should be urgently considered. From this point of view, this study was aimed to develop surface treatment systems for concrete structures, which cover physical properties, long term durability and economic consideration. Developing the optimal surface treatment materials, powder type polymer or liquid type polymer was added to inorganic base materials. Three surface treatment materials which had shown best results in primary tests were selected and durability tests were fulfilled. Consequently optimum surface treatment material was developed. The surface treatment materials, which were developed through this study, can efficiently extend the service life of concrete structures. As a result, the life cycle cost should be reduced and the waste of material resources would be cut down.

• 패션비즈니스
• /
• 제10권6호
• /
• pp.122-130
• /
• 2006

The purpose of this study is to develop the appropriate brassiere pattern for women. Total of 6 brands with same design and 75A, 80A size brassieres(total 12 brassieres) were compared and analyzed for pattern, cup size and patterns. SPSS 10.1 statistic process was used for data analysis. The outcom of this study is summarized as follows. Total length of brassiere by grade were performed smaller than the standard difference 5cm. For 1/2 front cover length, There were no significant differences between 75 and 80. The reason for lower line of wing is shorter than upper line of wing is because side support is cut side ways considering lower line of wing is sewn more toward front than upper line of wing. Even it is same A cup size most cup related sizes become larger according to underbust comparing with cup capacity, they range from 146.67cc to 172.83cc for same A cups. Among same A cups with difference underbust there was average of 26.16cc differences. For relations of material, sewing technology and expansion rate, all 6 brands had zigzag type sewing for upper line tape. For every 0.3cm height, there were $17{\sim}21$ stitches. When urethane mixture is similar expansion rate is higher while number of 1 inch zigzag are high. For elasticity, zigzag stitch expand side ways for more expansion.

• 한국산학기술학회:학술대회논문집
• /
• 한국산학기술학회 2010년도 춘계학술발표논문집 2부
• /
• pp.653-656
• /
• 2010

개착식 구조물의 내진성능 예비평가는 설계자료나 현장조사를 토대로 지진도 그룹, 취약도 지수, 영향도 지수를 산정하여 내진성능 상세평가의 시행여부를 판단하는 근거가 되어왔다. 내진성능 예비평가를 적용했던 사례를 분석한 결과 평가항목 산정 시 근거가 미약하고, 내진성능 상세평가 대상으로 분류되지 않은 그룹에 대해 구조적 내진성능 확보가 불확실하여 내진성능 예비평가를 개정하였다. 개정한 내진성능 예비평가는 지진도 그룹, 취약도 지수, 영향도 지수를 적용하는 기존의 틀은 유지하면서 평가항목을 산정하는 근거를 명확하게 하였으며, 내진성능 상세평가를 실시하지 않는 그룹에 대해서도 간략하게 구조적 내진성능 확보여부를 검토할 수 있는 전단변형각을 도입하였다. 본 연구에서는 개정한 내진성능 예비평가를 기존 사례에 적용하여 결과를 도출하였으며, 기존의 적용 사례와 비교 분석하였다.

• 한국잡초학회지
• /
• 제31권2호
• /
• pp.167-174
• /
• 2011

본 연구는 콩 재배시 동계 피복작물인 크림손클로버, 헤어리벳치, 호밀의 예취물 피복이 잡초발생과 콩생육 및 수량에 미치는 영향을 알아보고자 실시되었다. 연구 결과 크림손클로버, 호밀, 헤어리벳치 피복구에서 모두 이른 봄 잡초 억제율이 높았으며, 콩 정식 64일 후에도 헤어리벳치 피복구는 87.6%, 호밀 피복구는 72.0%로 콩의 초관이 형성될 때까지 높은 잡초억제율이 유지되었다. 그러나 크림손클로버 피복구는 시간에 흐름에 따라 잡초억제율 감소폭이 커서 여름잡초가 많이 발생한 콩 정식 64일 후에는 4.1%로 현저하게 감소되었다. 헤어리벳치 피복구는 월년생과 다년생잡초에 대한 억제율이 98.2%로 가장 높았고, 호밀 피복구는 광엽잡초 억제율이 57.6%인 반면, 화본과잡초 억제율은 93.8%로 광엽잡초 보다 화본과 잡초에 대한 억제 효과가 높았다. 크림손클로버 피복구에서는 다년생과 월년생잡초 억제효과가 거의 없었으며, 광엽잡초에 대한 억제효과도 없었다. 콩의 후기 영양생장기에 초장을 조사한 결과 무피복에 비해 크림손클로버, 헤어리벳치, 비닐 피복구에서 각각 6.9%, 20.2%, 22.0% 초장이 더 길었으나, 호밀 피복구는 오히려 초장이 짧았다. 콩의 입비대시에는 호밀 피복구의 콩 생육이 다소 회복이 되었으며, 수확기때 콩 수량은 헤어리벳치 피복구 ${\fallingdotseq}$ 비닐 피복구 > 크림손클로버 피복구 ${\fallingdotseq}$ 호밀 피복구 > 무피복구 순이었다.

• 헤리티지:역사와 과학
• /
• 제54권1호
• /
• pp.220-237
• /
• 2021

국가민속문화재 전 순정효황후 주칠 나전가구(傳 純貞孝皇后 朱漆 螺鈿家具) 매트리스의 제작 기법 및 사용 재료의 특성을 확인한 후 보존처리를 진행하였으며, 창덕궁 대조전 매트리스와 비교하여 1920~30년대 국내에서 사용된 매트리스의 특징을 확인해보고자 하였다. 전 순정효황후 매트리스 분석 결과, 프레임은 소나무과 솔송이 사용되었으며, 구조부인 웨빙, 트와인은 마섬유로 확인되었다. 충전재인 버랩은 마섬유, 초석은 벼속, 그 외 충전재는 면섬유로 확인되었다. 커버 상단은 레이온, 하단은 면섬유가 사용되었다. 사용된 재료와 내부 구조를 확인한 결과, 서양 가구인 데이베드와 의자에서 주로 사용되는 업홀스터리로 제작되었다. 보존처리 과정에서는 분석 결과를 바탕으로 유사한 재료를 사용하였으며, 해체 → 세척 → 보수 및 보강 → 조립의 순으로 진행하였다. 해체 과정에서 상단의 커버가 새롭게 발견되었으며, 충전재인 버랩에서 요코하마, 고베, 조선의 단어가 발견되었다. 하지만 제작사나 제작 장소를 특정할 수 있는 추가적인 흔적은 발견되지 않았다. 구조부와 충전재, 커버는 건식 세척을 진행한 후 업홀스터리 구조에서 기존 재료는 제거하지 않고 유사한 재료를 사용하여 보수 및 보강을 진행하였다. 구조부 웨빙은 동종의 재료를 사용하여 보강하였으며, 스프링의 배열 및 고정은 트와인을 사용하여 목재 프레임에 고정하였다. 손상된 면천과 버랩은 유사한 소재의 보강재를 덧댄 후 바느질하였다. 상단 커버는 손상부에 보강 직물을 마름하여 안쪽에 넣고 바느질하였다. 조립은 해체의 역순으로 진행하였다. 스프링과 닿는 부분에 동일 소재의 버랩을 삽입하여 고정한 후 충전패드, 보강천, 초석, 면천, 솜포, 커버 보호용 광목천, 커버를 씌워 택으로 마무리하였다. 순정효황후가 사용한 2개의 매트리스는 제작 시기의 차이가 있을 뿐 프레임과 충전재, 커버로 구성된 서양의 업홀스터리로 제작되었다. 보존처리 과정에서 새로운 벨벳 커버가 발견되었고 이전 수리 흔적이 확인되었으며, 충전재로 초석, 가마니와 짚풀 등이 확인됨에 따라 제작 환경에 따른 사용 재료의 변화를 확인할 수 있었다. 향후 근대문화재 업홀스터리 의자 또는 소파의 보존처리에서 사용 재료 및 제작 방법의 변화를 살펴볼 수 있을 것으로 기대된다.