• Journal of Ecology and Environment
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• 제38권2호
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• pp.249-256
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• 2015

Islands are often habitats to unique species because they have different environmental conditions from the mainland and other islands. Another characteristic of islands is their limited natural resources, which has led island residents to heavily rely on traditional ecological knowledge (TEK) and use resources sustainably. The so-called "Maeul landscape" shows the interrelationship of biological species and people's use of natural resources. Shinan-gun is an administrative district located in the southwestern part of Korea that forms an archipelago with huge tidal flat areas. Since long ago, people's use of these tidal flats shows a high degree of biocultural diversity. Maeul landscapes also show humans' adaptation to the natural environment. For instance, strong winds blowing mainly from the northwest have led people in Shinan-gun to create "Ushil," a windbreak forest with stone blocks to block wind from their villages and agricultural fields. At present, the transfer of TEK to future generations is at stake due to socio-economic changes that cause island populations to shrink and age rapidly. Islands are often regarded as good destinations for tourism, but attention should also be given to sustainable development due to the environmental characteristics of islands. International organizations are making efforts to curb the threats of global environmental problems especially on small islands. Their activities are aimed at seeking solutions that stress the central role of biocultural diversity in establishing the sustainable use of natural resources on islands. Joint efforts oflocal people and government authorities to protect and conserve the Maeul landscape should be encouraged.

• Journal of information and communication convergence engineering
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• 제7권3호
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• pp.275-280
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• 2009

While database(DB) and information retrieval(IR) have been developed independently, there have been emerging requirements that both data management and efficient text retrieval should be supported simultaneously in an information system such as health care, customer support, XML data management, and digital libraries. The great divide between DB and IR has caused different manners in index maintenance for newly arriving documents. While DB has extended its SQL layer to cope with text fields due to lack of intact mechanism to build IR-like index, IR usually treats a block of new documents as a logical unit of index maintenance since it has no concept of integrity constraint. However, In the DB-IR integrations, a transaction on adding or updating a document should include maintenance of the posting lists accompanied by the document. Although DB-IR integration has been budded in the research filed, the issue will remain difficult and rewarding areas for a while. One of the primary reasons is lack of efficient online transactional index maintenance. In this paper, performance of a few strategies for per-document basis transactional index maintenance - direct index update, pulsing auxiliary index and posting segmentation index - will be evaluated. The result shows that the pulsing auxiliary strategy and posting segmentation indexing scheme, can be a challenging candidates for text field indexing in DB-IR integration.

• 에너지공학
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• 제6권1호
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• pp.87-95
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• 1997

금속염화물과 암모니아간의 가역반응을 이용한 화학열펌프는 비프레온계 냉동 냉장시스템으로서 환경규약의 제한이 없고 가스, 전기 및 산업폐열 등 다양한 구동열원을 사용할수 있으며 축열에 의한 에너지 저장이나 산업공정에서의 대용량 에너지관리 시스템 등 응용분야가 다양한 장점을 갖고 있다. 통상 소규모의 실험실 장치에서 파일롯트 플랜트(pilot plant)로 전환하는 과정에서 시스템의 성능에 대한 해석이 필요하며 화학반응기의 거동에 대한 컴퓨터 모사도 필수적이다. 따라서 본 연구에서는 작동조건에 따라 화학식 냉동기 성능계수가 어떻게 변하는지를 예측하였고 반응기 모델링에 의한 동적모사를 수행하여 반응기의 온도거동, 작동조건에 따른 전화율 변화, 반응혼합물의 제조변수가 냉동기 성능에 미치는 영향 등을 고찰하였다.

• 패션비즈니스
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• 제8권5호
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• pp.75-84
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• 2004

Fashion Illustration has become a key method in expressing Fashion, and is being applied in various fields of the modern world, where changes are so rapid that prescribing trends are meaningless. Fashion Illustration was stimulated through progress of wood block printing and development of printing techniques, and grew with fashion magazines. Fashion Illustration advanced along with the appearance of newspapers and magazines that were emerged due to historical demands such as development of printing techniques, spacial spread of human life, obliteration of traditional societies, diffusion of education systems, progress in postal systems, and appearance of commercial broadcast. Fashion Illustration showed growth and decline along with the influence of mass media such as magazines and photography, and the general publics demand. In this study, the author reviews Le Nouvau Mercure Galant, the magazine that first dealt with Fashion Illustrations. The author analyses the magazine in six stages of formation, growth, revolution, golden-age, decline, and reconstruction, to develope a theoretical analysis of Fashion Illustration and to give direction of use of Fashion Illustration in the future.

• Water Engineering Research
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• 제3권1호
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• pp.31-44
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• 2002

The effect of diurnal cycle, intermittent visit of observation satellite, sensor installation, partial coverage of remote sensing, heterogeneity of soil properties and precipitation to the soil moisture estimation error were analyzed to present the global sampling strategy of soil moisture. Three models, the theoretical soil moisture model, WGR model proposed Waymire of at. (1984) to generate rainfall, and Turning Band Method to generate two dimensional soil porosity, active soil depth and loss coefficient field were used to construct sufficient two-dimensional soil moisture data based on different scenarios. The sampling error is dominated by sampling interval and design scheme. The effect of heterogeneity of soil properties and rainfall to sampling error is smaller than that of temporal gap and spatial gap. Selecting a small sampling interval can dramatically reduce the sampling error generated by other factors such as heterogeneity of rainfall, soil properties, topography, and climatic conditions. If the annual mean of coverage portion is about 90%, the effect of partial coverage to sampling error can be disregarded. The water retention capacity of fields is very important in the sampling error. The smaller the water retention capacity of the field (small soil porosity and thin active soil depth), the greater the sampling error. These results indicate that the sampling error is very sensitive to water retention capacity. Block random installation gets more accurate data than random installation of soil moisture gages. The Walnut Gulch soil moisture data show that the diurnal variation of soil moisture causes sampling error between 1 and 4 % in daily estimation.

• International Journal of Aeronautical and Space Sciences
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• 제16권1호
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• pp.8-18
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• 2015

A numerical simulation for a nonslender BWB UCAV configuration with a rounded leading edge and span of 1.0 m was performed to analyze its aerodynamic characteristics. Numerical results were compared with experimental data obtained at a free stream velocity of 50 m/s and at angles of attack from -4 to $26^{\circ}$. The Reynolds number, based on the mean chord length, is $1.25{\times}106$. 3D multi-block hexahedral grids are used to guarantee good grid quality and to efficiently resolve the boundary layer. Menter's shear stress transport model and two transition models (${\gamma}-Re_{\theta}$ model and ${\gamma}$ model) were used to assess the effect of the laminar/turbulent transition on the flow characteristics. Aerodynamic coefficients, such as drag, lift, and the pitching moment, were compared with experimental data. Drag and lift coefficients of the UCAV were predicted well while the pitching moment coefficient was underpredicted at high angles of attack and influenced strongly by the selected turbulent models. After assessing the pressure distribution, skin friction lines and velocity field around UCAV configuration, it was found that the transition effect should be considered in the prediction of aerodynamic characteristics of vortical flow fields.

• International Journal of Naval Architecture and Ocean Engineering
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• 제9권2호
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• pp.219-226
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• 2017

These days, the great part of design processes in the field of ship or offshore manufacturing are planned and implemented using the CAD system customized for shipbuilding companies. It means that all information for design and production could be extracted and reused at the other useful fields which need cost considerable time and efforts. The typical example is the field of welding material quantity evaluation which is demanded during the construction of ship or offshore structures. The proper evaluation of welding material to be used and the usage of them at the stage of schedule planning are mostly important to achieve the seamless process of production and costing in advance. This study is related to the calculation of welding length and needed welding material quantity at the stage of design completion utilizing the customized CAD system. The calculated welding material quantity would be classified according to welding posture, assembly stage, block, bevel and welding type so as to improve the accuracy of total cost evaluation. Moreover it is possible to predict the working time for welding operation and could be used efficiently for the cost management using the results of this research.

• 한국전자파학회논문지
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• 제9권1호
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• pp.1-7
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• 1998

모노폴 안테나를 갖는 휴대폰의 근거리 전자계블 맥스웰 방정식의 적분형을 이용한 FDTD 수식으로부터 계산 하였다. 이 전자계 값을 기존의 맥스웰 방정식의 미분형인 FDTD 수식에 대입하여 頭部의 전자파 노출 부위에 따른 SAR 분포플 계산하였다. 頭部는 유전율과 도전율이 같은 각 부분을 5 mm 크기인 80,000 개의 정육면체 셀로 분할하였고 휴대폰의 입력 전력은 0.6 W 이며 동작 주파수는 833 MHz로 하였다. 안테나로부터 2cm 떨어진 거리에서 頭部모형내 유기되는 최대 SAR 값은 1.5 [W/kg] 이었으며 이 값은 IEEE 의 안전기준인 1.6 L [W /kg] 이하임을 알 수 있다.

• 한국정밀공학회지
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• 제15권7호
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• pp.149-159
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• 1998

The importance of soundness and safety evaluation in weld zone using by the ultrasonic wave has been recently increased rapidly because of the collapses of huge structures and safety accidents. Especially, the ultrasonic method that has been often used for a major non-destructive testing(NDT) technique in many engineering fields plays an important role as a volume test method. Hence, the defecting any defects of weld Bone in austenitic stainless steel type 304 using by ultrasonic wave and neural network is explored in this paper. In order to detect defects, a distance amplitude curve on standard scan sensitivity and preliminary scan sensitivity represented of the relation between ultrasonic probe, instrument, and materials was drawn based on a quantitative standard. Also, a total of 93％ of defect types by testing 30 defect patterns after organizing neural network system, which is learned with an accuracy of 99％, based on ultrasonic evaluation is distinguished in order to classify defects such as holes or notches in experimental results. Thus, the proposed ultrasonic wave and neural network is useful for defect detection and Ultrasonic Non-Destructive Evaluation(UNDE) of weld zone in austenitic stainless steel 304.

• 비파괴검사학회지
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• 제22권1호
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• pp.59-64
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• 2002

CANDU형 핵연료채널 압력관(Zr-2.5%Nb)과 calandria관(Zircaloy-2)에 대한 원격장 와전류탐상의 자계분포특성을 파악하기 위하여 유한요소 해석을 수행하였다. 압력관과 칼란드리아관의 전자기장 분포와 위상각 해석을 통하여 최적 검사 주파수와 감지코일의 위치를 평가하였다. 또한 축대칭 구조물(Al-ring과 Al-block)이 공존시 파라미터해석을 통하여 원격장 와전류의 특성을 평가하였다.