• 한국정보전자통신기술학회논문지
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• 제5권3호
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• pp.127-137
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• 2012

본 연구는 공기제동의 문제점을 보안하기 위한 유지보수와 환경문제, 효율성, 경제성 등을 개선하기 위하여 정지에서 고속영역까지의 전 영역에서 전기제동을 사용하는 방법이 제시되었다. 전기적으로 완전제동을 위한 2가지 방법으로 인버터 출력전압의 증대에 의한 방법과 전동기와 인버터 사이에 직렬저항을 삽입하는 방법을 통하여 경제적이며 실제 적용이 가능한 제어방법인 직렬저항을 삽입하는 방법을 적용하기로 하였다. 직렬저항에 의한 전력손실을 감소시키기 위한 직렬저항을 단락 하는 방법을 사용하여 효율을 개선하고 전 영역에서의 제동력확보는 실험환경 내에서 우수한 인버터의 단자전압을 상승시키는 방법과 동일한 특성을 보였다.

• 한국항만학회지
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• 제6권1호
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• pp.69-91
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• 1992

A new type of horizontal submerged break water or fixed structure to control waves near coastal area is introduced to focus wave energy before or behind it. Intentionally, the water depth near the structure is changed gradually to get a refraction and diffraction effect. The concentration of wave energy due to the structure was analyzed for the selected design of structure. The shape of the submerged structure in consideration is a circular combined with elliptical curve not to cause reflection of waves at the extreme edge of the structure but cause wave scattering. The direction of the structure against the incident wave is changed easily in the model Applying a regular wave train the following were examined. 1) whether a crescent plain submerged structure designed by the wave refraction theory can concentrate wave energy at a focal zone behind and before it without wave breaking phenomenon. 2) Location of maximum wave amplification factor in terms of the incident wave direction, wave period, etc. In any event the study would contribute to control waves near coastal area and to protect a beach from erosion without interruption of ocean view it is an useful study for the concentration of wave energy efficiently with the increase of wave height.

• International Journal of Internet, Broadcasting and Communication
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• 제15권2호
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• pp.73-80
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• 2023

As a result of this study, the income generation effect of local universities on the local economy through the Daranee (1976) model was found to be 110.9 billion won (direct and indirect income 78 billion won, induced income 32.9 billion won). In the case of Korea, it has been verified through a number of previous studies that local universities play a role in preventing the outflow of local talent to the metropolitan area. Considering this, it seems that the government should make bold investments to foster local universities in terms of balanced national development. This is because the movement of local talents to the metropolitan area not only undermines the growth potential of the provinces and undermines the basis for regional existence, but also creates a vicious cycle that hinders balanced national development. To break this vicious cycle, the development of local universities is very important. It is judged that the horizon of balanced national development will be opened when local universities revitalize the local economy through the government's bold investment in local universities and are reborn as entities that provide various services based on the facilities and equipment of local universities.

• Journal of Forest and Environmental Science
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• 제40권1호
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• pp.24-34
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• 2024

Fire, being primarily a natural phenomenon, is impossible to control, although it is feasible to map the forest fire risk zone, minimizing the frequency of fires. The spread of a fire starting in any stand in a forest can be predicted, given the burning conditions. The natural cover of the land and the safety of the population may be threatened by the spread of forest fires; thus, the prevention of fire damage requires early discovery. Satellite data and geographic information system (GIS) can be used effectively to combine different forest-fire-causing factors for mapping the forest fire risk zone. This study mainly focuses on mapping forest fire risk in the Madikhola watershed. The primary causes of forest fires appear to be human negligence, uncontrolled fire in nearby forests and agricultural regions, and fire for pastoral purposes which were used to evaluate and assign risk values to the mapping process. The majority of fires, according to MODIS events, occurred from December to April, with March recording the highest occurrences. The Risk Zonation Map, which was prepared using LULC, Forest Type, Slope, Aspect, Elevation, Road Proximity, and Proximity to Water Bodies, showed that a High Fire Risk Zone comprised 29% of the Total Watershed Area, followed by a Moderate Risk Zone, covering 37% of the total area. The derived map products are helpful to local forest managers to minimize fire risks within the forests and take proper responses when fires break out. This study further recommends including the fuel factor and other fire-contributing factors to derive a higher resolution of the fire risk map.

• 한국측량학회:학술대회논문집
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• 한국측량학회 2004년도 춘계학술발표회논문집
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• pp.263-266
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• 2004

We make DEM of the area that elevation value varies rapidly by the aid. This study evaluates the accuracy and workability between the existing DEM making mathod by processing break line and the DEM absorption method by using the program like ARC TIN or AML. The object data of DEM generation is 1/5,000 digital map publicated by NGII and this study uses 100pieces of map as the criteria. We correct the error by Geoconv and generate DEM by using ARC TIN, ARC VIEW. Accuracy Evaluation accomplished by drawing 100 points from 1/5000 digital map.

• 디자인학연구
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• 제19권3호
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• pp.71-92
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• 2006

People have their own cultural backgrounds and experiences in terms of visual perceptional thinking so that they could misunderstand the cultural symbols, trademarks, Brand Identities, and trade characters, especially, animal trademarks. Sometimes Easterners and Westerners seem to not comprehend the different meanings of the cultural symbols. The signs of twelve Chinese zodiac animals are the typical symbol of the Asian mythology. What I wanted to focus on emphasizing the different views and perspective of an animal trademark is according to the Chinese Zodiac between Eastern and Western cultures. Generally, multiple symbolisms are difficult to comprehend, because they are created by individual ideas and incorporate several mythologies and histories. How do Westerners interpret the implied meaning of Eastern animals in general? How are they going to understand the Eastern animal logos or marks accurately? How can we solve the problem to make people understand their different meanings? There were some confusing pictorial images in the area of the design field when a designer creates an animal mark for globalization and localization. Creating of hybrid symbol is the best way to break the communication barriers with people all around the world.

• 전기학회논문지
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• 제56권1호
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• pp.100-105
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• 2007

Signalling equipments at railroad sites are widely exposed to high voltage lightning surges. This paper presents a lightning protection system for the signalling equipments at subway car depots. The main features of the system are as follows : (1)the common grounding system between power system grounds and the signaling system grounds, (2)physical and chemical methods to reduce grounding resistivity, (3)rearrangement of lightning rods based on the rolling bal1 theory, (4)equi-potential bonding networks to minimize the potential differences between the equipments grounds. The system has been constructed at six subway car depots in Seoul metropolitan area and it is measured that the grounding resistivity are reduced to 0.266 ohms and the potential differences between devices are reduced to a negligible quantity. After the construction of the systems, it has not been reported the break-down of the signalling equipments caused by lighting surges.

• Journal of Welding and Joining
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• 제15권3호
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• pp.47-55
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• 1997

Dynamic characteristics of the short circuit mode are investigated using the Volume of Fluid (VOF) method. When the initial molten drop volume, contact area and wire feed rate are given, rate change of the molten bridge profiles, pressure and velocity distributions are predicted. The electromagnetic force with proper boundary conditions are included in the formulation to consider the effects of welding current. It is found that the molten metal is transferred to the weld pool mainly due to the pressure difference caused by the curvatures in the initial stage, and electromagnetic force becomes dominant factor in the final stage of short circuit transfer. Necking occurs at the contact position between the molten drop and weld pool, and the initial molten drop volume and welding current have significant effects on break-up time.

• 한국강구조학회 논문집
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• 제8권3호통권28호
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• pp.47-54
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• 1996

Recently Sucessive progress in train technic has enabled us to constructed high-speed railways for ourselves. This caused more rapid train more pressure on a track and speedier track break-down. Especially in the construction of high-speed rails for high-speed traveling and safety accurate breaking distance is essential and not only computation of rolling resistance in theory but also verification through real measurement are important in basic material for breaking and starting load caused during the train running. In this study, we measured traveling resistance and calculated traveling resistance formula in the case of the SAEMA-EUL which consists of main part of current passenger trains and frights in this country.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2015년도 제46회 하계학술대회
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• pp.655-656
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• 2015

In this paper, diagnosis for 85 high voltage induction motors which have operated for more than 20 years in 18 wide area water supply offices were applied and the results of diagnosis were analysed. Furthermore, main factors that would be affecting rotor defects were selected and correlations between dependent variables which was magnitude for sideband frequency on current during operation and independent variables such as starting characteristic, operating time, number of operation, load factor, maker, rotation speed, capacity were analysed. It was clear that factors including starting characteristic, number of operation, maker, rotation speed caused break by correlation analysis. From this, regression equation was deduced through regression analysis. Based on suggested regression equation, it is applied usefully that we can estimate the condition of rotor without onsite diagnosis and plan the schedule of diagnosis.