• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2022년도 봄 학술논문 발표대회
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• pp.253-254
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• 2022

In this study, catechol-functionalized chitosan (Cat-Chit), a well-known bioinspired polymer that imitates the basic structures and functions of living organisms and biological materials in nature, was synthesized and combined with cement mortar in various proportions. The compressive strength, tensile strength, drying shrinkage, accelerated carbonation depth, and chloride-ion penetrability of these mixes were then evaluated. In the ultraviolet-visible spectra, a maximum absorption peak appeared at 280 nm, corresponding to catechol conjugation. The sample containing 7.5% Cat-Chit polymer in water (CPW) exhibited the highest compressive strength, and its 28-day compressive strength was ~20.2% higher than that of a control sample with no added polymer. The tensile strength of the samples containing 5% or more CPW was ~2.3-11.5% higher than that of the control sample. Additionally, all the Cat-Chit polymer mixtures exhibited lower carbonation depths than compared to the control sample. The total charge passing through the samples decreased as the amount of CPW increased. Thus, incorporating this polymer effectively improved the mechanical properties, carbonation resistance, and chloride-ion penetration resistance of cement mortar.

• Advances in nano research
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• 제17권3호
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• pp.249-255
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• 2024

The paper discusses the potential of nanomaterials in revolutionizing basketball equipment by applying them to advance padding and shock absorption technologies in order to bring more control and comfort to the players. Nanotechnology devised new solutions for the challenges that the players are exposed to by dealing with issues such as better control reducing shock to the hands and wrists during those most decisive periods of every game: dribbling, passing, and catching. This work embeds nanomaterials in basketballs to understand their efficacy in reducing the amount of force transmitted to players, thereby reducing the risk of injuries and fatigue. The research gives an in-depth look into the structural properties and performance benefits of nanomaterial-enhanced padding in balls for optimized comfort and control to players and improvement in the dynamics of gameplay. The future of nanotechnology in the design of basketball equipment finds further bases in an in-depth analysis and is experimentally validated with respect to the prospects of a ball that is safer, long-lasting, and with improved performance.

• 한국터널지하공간학회 논문집
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• 제22권4호
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• pp.347-365
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• 2020

도시지역의 교통난 해소와 녹지공간의 확보를 위해 도심지 터널이 증가하면서 차량의 정체 가능성이 높은 터널에 대한 제·배연방식으로 대배기구에 의한 집중배기방식의 적용이 증가하는 추세에 있다. 집중배기방식의 배연성능은 배연풍량 뿐만 아니라 배기구(댐퍼)의 형상이나 배기풍속 등 다양한 인자에 의해서 영향을 받는 것으로 알려져 있다. 이에 본 연구에서는 각국의 배연시스템 설계기준 및 설치현황을 알아보고 배연풍량이 동일한 경우에 배연댐퍼 사이즈에 따른 배연성능을 연기 이동거리 측면에서 수치시뮬레이션을 수행하여 비교·평가하였으며, 다음과 같은 결과를 얻었다. 배연댐퍼의 단면적이 증가할수록 배기팬에 근접한 댐퍼에서 배기풍량이 집중되어 화재 하류의 댐퍼의 배연풍량이 감소하여 하류측의 연기 이동거리가 증가하는 현상이 발생한다. 이와 같은 현상을 방지하기 위해서는 배연댐퍼의 단면적을 작게하여 통과풍속을 높게 함으로써 댐퍼통과 시 압력손실이 증가하도록 하여 배기구간에서 배연풍량의 불균일성을 완화할 필요가 있다. 본 해석범위에서는 배연댐퍼의 설치간격이 50 m인 경우에는 설계통과풍속이 4.4 m/s (댐퍼면적: 2.34 ㎡ = 1.25 × 1.85 m) 이상, 댐퍼의 설치간격이 100 m인 경우에는 설계통과풍속이 4.84 m/s (댐퍼면적: 3.38 ㎡ = 1.5 × 2.25 m) 이상일 때 배연성능확보에 유리한 것으로 나타났다.

• 한국환경복원기술학회지
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• 제4권1호
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• pp.80-89
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• 2001

The objective of this study was to introduce the current status and development strategy for the environmental restoration of stream side in Japan, and to consider the methodology which could be effectively applied to the environmental restoration of stream side in Korea. 1. We should establish a new paradigm of forest conservation and erosion control which can emphasize the restoration of the stream side ecosystem and reduce soil movement in the areas. Also, in the past, the objective of forest conservation and erosion control was to fix soil by constructing permanent structures. The direction of future forest conservation and erosion control needs to be new forest conservation and erosion control technology to prevent large scale soil movement but allow small scale soil movement to conserve sound ecosystem and biotic habitats. 2. In the past, the goal of forest conservation and erosion control planning was to fix the amount of soil movement by constructing permanent facilities. Forest conservation and erosion control planning in the future needs to change the techniques which could prevent soil movement from large scale of soil disasters, but allow soil movement effectively to a small and middle scale's soil movement. Also, it is considered to change erosion control dams from non passing type to passing type. 3. In the point of ecological conservation aspects, we should evaluate the effects of new forest conservation and erosion control methods which are emphasized on the restoration of the stream side ecosystem. Also, forest conservation and erosion control construction projects for restoring stream and river ecosystem should be planned for perfectly restorating their ecosystems by the way of sustainable maintenance and management. 4. The restoration direction of stream and river ecosystems needs to be restoring the diversity of small geographies such as waterway, shoal and puddles rather than flattening stream bed. And the restoration of the stream side ecosystem should provide continuity of the stream side environment which allows desirable biological habitats, and environmentally sound facilities to harmonize with the environment.

• 스마트미디어저널
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• 제9권4호
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• pp.97-101
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• 2020

본 연구에서는 센서상의 전하량 변화를 통하여 전위차를 측정할 수 있는 수동형 전기장센서를 이용하여 사람의 손동작에 의해 유발되는 신호를 측정 장치의 전원이나 주변 전력선에 의해 센서에 유입되는 잡음(PLN: Power Line Noise)의 고조파 성분을 분석하여 동작신호를 검출하고 추출하는 연구를 수행 한다. 전기장 센서에 유입되는 전력선잡음으로 센서가 사람의 존재, 접근, 동작에 의해 영향 받는 사실을 이용해 PLN의 주성분인 60Hz 고조파 성분의 스펙트럼분석을 수행하여 PLN 신호의 증가 또는 감소를 식별할 수 있고 상대적으로 동작에 민감한 120Hz 성분을 이용한다. FFT를 사용하여 120Hz의 신호성분이 특정 임계값을 통과할 때 신호를 검출하는 방법이다. 동작이 탐지되는 경우 임계값을 기준으로 프레임을 결정한다. 본 연구의 방법을 이용하여 얻은 동작 감지 성공률은 약 90% 수준을 달성하였다. 이렇게 감지된 동작신호로 추출한 프레임의 정확도는 약 85%이다. 수동형 전기장 센서를 이용하여 동작신호를 PLN을 이용하여 동작검출에 이용한 연구사례는 국내외적으로 드문 사례이며, 본 논문에서는 PLN이 상존하는 실내 적용환경에서 유망하게 활용될 수 있다.

• 한국구조물진단유지관리공학회 논문집
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• 제26권2호
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• pp.68-75
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• 2022

본 연구에서는 PSC 구조물의 프리스트레스를 직접적으로 평가하기 위해 헤테로코어 광섬유를 활용하여 콘크리트의 변형량 계측을 기반으로 하는 새로운 센서모듈을 제안하고 성능실험을 수행하였다. 헤테로코어 광섬유는 전송로의 특정 부분이 구부러지면 광 손실이 발생하며, 곡률의 크기에 따라 광 손실량이 선형적으로 변한다. 센서모듈의 계측 성능과 광섬유의 적용성을 확인하기 위해 센서모듈에 변형을 발생시키며 광섬유를 통과하는 빛을 전력으로 변환하여 측정하였다. 센서모듈을 매립시킨 지름 15cm, 높이 35cm의 원주형 콘크리트 공시체에 최대 변형량 0.5mm을 0.12mm/min의 속도로 발생시키는 동안 광섬유를 통과한 빛은 변형과의 관계에서 0.9333의 선형성을 가지는 것을 확인할 수 있었다. 이번 실험의 결과를 통해 헤테로코어형 광섬유를 활용한 센서모듈을 구조물에 매립하여 콘크리트 압축변형량 계측을 통해 PSC 구조물의 프리스트레스를 직접적으로 평가하는 것이 가능할 것으로 판단되며, 앞으로 진행될 PSC 부분 거더 모델 실험에 적용할 쉬스관 일체형 센서모듈 개발에 유용한 자료로 활용될 수 있을 것으로 판단된다.

• 한국식품영양학회지
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• 제24권4호
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• pp.589-601
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• 2011

The purpose of this study was to investigate changes in the cooking process of $Pat-juk$(red beans porridge), $Jat-juk$(pine-nut porridge) and $Tarak-juk$(milk porridge) in cooking books published after Korean modern era, approximately from late 19th century to the present. We analyzed 11 historical cook books were analyzed. It is found that the amount of red beans used for $Pat-juk$ was the same or more than that of rice but never less than rice. Only one cook book suggested sugar as seasoning for final taste, but all the other cook books mentioned salt for final taste. $Hangukeumat$(1987) suggested the method for obtaining optimum color for $Pat-juk$. After smashing and passing through the cooked red beans, collecting the red bean water to boil first and then adding the passed through red beans to boil together, in which rice will be added the last to be boiled. For $Jat-juk$, the ratio of the amount of pine-nut and rice were varied among cook books that the amount of pine-nut can be more, same or less than rice. $Jat-juk$ can have salty or sweet, so sugar, honey or salt were used for final seasoning. Pine-nut and rice were cooked together or cooked successively depending on cook books. The changes in cooking procedures of $Tarak-juk$ were the portion of milk used and the method of preparing rice before making the porridge. Firstly, the portion of milk increased over time. $Tarak-juk$ can be also tasting both sweet or salty, so sugar or salt was used for final seasoning. Secondly, two method of preparing rice were found; one is that rice was ground after soaking in water and the other is that rice was ground and toasted before putting into the porridge. When the ground rice was toasted, the milk was added with water at the same time because the cooking time of the porridge with toasted rice was shortened so that the milk could be added earlier than the other method without the risk of sticking on the bottom of the pot. In further studies, the cooking procedures used in the previous period of the late 19th century should be examined. Also after restoring all the cooking methods suggested in cook books, the comparison of the sensorial and nutritional value needs to be carried out for applying or reinventing new recipe for food industry.

• 복식
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• 제41권
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• pp.185-206
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• 1998

The purpose of this study was to improve productivity for maximum effects with the present equipments and staff. This study compared and analyzed the mea-sured time by using stop watch method and MTM, which was the new measuring method. The flow and results of this study were as follows: 1. This study investigated the theoretical background the efficiency for production management, and the way of productivity improvement through documentary research. 2. Setting up the standard flow on the experi-mental company production, making out a process chart and measuring the actual working hour. 3. The study measured the allowance time applying work sampling. 4. Each process of the movement analysis was filmed by video to use basic data. 5. MTM analysis was taken by choosing 10 processes from front bodice according to the basic movement of MTM. Through the results, this study exclude unneccesary movements and suggest a method for working ways. 6. Using the actual working hour measured by a stop watch calculated the pitch time and presumed the amount of daily productivity. 7. The result of the work sampling came out as 38% of allowance rate. It was 13% higher than the standard amount of woman's jacket allowance rate, which was 25%. The most influencing factor was work discussion. That was because there were commuication problem of the work way between the operator and leader. More adequate use of flow table and level passing table was needed. There were the problems that inappropriate places and sizes made the distance of movements longer and often needed more adjustment of works and surroundings. To prevent breakdowns equipments check ups were necessary before works. 8. The results of MTM analysis were as follow : the time was reduced 40% than the actual measured time by a stop watch. This was because the leveling of the operator was included in the real calculation. Also, leveling was included in MTM analysis and all the conditions were standarized. Therefore MTM method was a scientidic measuring way of establishing the standard time. The presented method of this study, suggested an ideal method eliminating unneccesary motions, and presented standardization of works. Improvement of working methods, work condition and simplifying motions in each 10 processes reduced the working time from total 656 seconds to 301 seconds. 9. The way and time of working was linked together in the MTM analysis methods. Thus data from MTM help suggest not only establishing standard time but also establishing stan-dard work. Plus it includes various ability for improvements of working ways. So it is an objective method which can be widely used in other work studies. 10. The function of a time study is to determine the amount of work produced with a given method. The work rate is used to establish the cost of labor. The wage of worker must be calculated per unit time which is deter-mined before the time study is made. This study tried to introduce the incentive rule for deciding wages according to the standard time by MTM method.

• 청정기술
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• 제25권1호
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• pp.19-32
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• 2019

여러 국가를 통행하는 다양한 형태의 선박에서 배출되는 황산화물에 의해 지역적인 대기오염이 심화됨에 따라 국제해사기구에서는 황산화물 배출제어지역을 설정하여 규제하고 있다. 이러한 지역적 규제를 만족시키기 위해서는 선박의 연료선택방법과 배가스 후처리 장치가 적용되고 있으나 경제적인 이유로 스크러버를 설치하여 배출되는 황산화물의 양을 저감하는 배가스 후처리 방법이 주로 선호되고 있다. 스크러버는 배출가스 중 황산화물을 액적에 흡수시켜 황산화물의 양을 저감하는 장치로 액적의 크기에 따라 스크러버의 성능이 좌우된다. 이러한 성능을 평가하기 위해서, 본 논문에서는 대향류형 스크러버와 사이클론 스크러버를 설계하고, 전산유체역학을 이용하여 각 액적의 크기에 따른 탈황 효율과 액적이 증발되는 양을 평가하였다. 평가 방법으로 스크러버 내부는 기체와 액체의 2상 유동을 가지기 때문에, Eulerian-Eulerian 해석 기법을 사용하였으며, 액적의 직경이 $100{\mu}m$, $300{\mu}m$, $500{\mu}m$와 $700{\mu}m$일 때 계산을 진행하여 스크러버를 분석하였다. 계산 결과, 2종류의 스크러버 모두 $500{\mu}m$와 $700{\mu}m$일 때 높은 탈황 효율과 낮은 증발량을 나타내었다.

• 문화기술의 융합
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• 제8권5호
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• pp.515-524
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• 2022

도시철도 침목플로팅궤도(STEDEF)의 분기기는 콘크리트 도상에 매입된 목침목과 침목 하부의 침목방진패드로 구성된 방진궤도로서 침목방진패드의 열화 및 이에 따른 스프링강성의 변화가 침목지지조건의 변화를 초래할 수 있다. 현재 약 21년의 공용기간 동안 발생된 망간크로싱의 손상수량은 전체 부설수량 대비 약 17%로 조사되었으며, 사용 기간 15년 이후(누적통과톤수 약 5.5억톤)부터 손상 물량이 증가하는 것으로 분석되었다. 본 연구에서는 실물 망간크로싱과 차륜의 형상을 모사한 3차원 수치모델을 이용한 매개변수 해석(차륜의 위치, 침목지지조건 및 동적 윤중의 크기)을 수행하여 실제 현장에서 발생된 망간크로싱의 손상유형 및 발생원인을 분석하였다. 연구결과, 노즈부 주변 침목에 뜬침목이 발생된 경우, 설계 궤도충격계수가 적용된 동적윤중 작용 시 노즈부 단면의 발생응력이 항복강도를 초과하였으며, 이는 실제 현장에서 발생된 손상위치와 비교적 잘 일치하는 것으로 분석되었다. 따라서 망간크로싱의 손상을 최소화하기 위해서는 노즈부 주변의 침목지지조건을 일정한 수준으로 유지하고, 손상된 망간크로싱 교체 시에는 침목 하부 경계조건의 균일성 확보를 위해 침목방진패드를 함께 교체하는 것이 바람직할 것으로 분석되었다.