• 한국전자파학회논문지
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• 제12권6호
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• pp.958-964
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• 2001

본 논문에서는 Bow-tie 다이폴 안테나를 변형시킨 계단형 Bow-tie 형태의 모노폴 안테나의 급전부의 안테나에 슬릿(slit) 장착 및 이면(裏面)의 접지면의 길이를 변화시키는 임피던스 정합 방법을 적용하여 광대역 특성을 갖는 안테나를 제안한다. 제안된 안테나의 길이는 1/4파장보다 작고, 대역폭은 2:1 VSWR의 범위에서 77.1 %, 1.7 GHz에서의 안테나 이득은 1.7 dBi를 얻었으며 방사패턴은 전 방향성을 가지고 있다.

• 한국안전학회지
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• 제35권4호
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• pp.48-55
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• 2020

The use of temporary Gondola has been steadily increasing. The temporary Gondola is required to get a safety certification review during installation and to be inspected during use within every six months. Most of them, however, are dismantled before six months, and inappropriate activities are conducted frequently for shorter working hours and convenience of work. In this study, the characteristics of the temporary Gondola and the domestic accident cases that occurred over the past 10 years(2008-2017) are analyzed for the type of accident, the state of the accident by year, and the actions of the workers in the event of an accident. Also comprehensive accident reduction measures were proposed by identifying the fundamental causes of temporary Gondola accidents, problems of existing preventive measures, and system defects by utilizing Bow-Tie techniques.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2017년도 추계학술대회
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• pp.238-240
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• 2017

파랑 중 선수파의 영향을 줄이기 위해 도입된 Axe Bow선형은 파랑 중 항해 시 선수부에 과도한 Spray현상이 발생한다. 이를 억제하고자 선수 부가물이 도입되었으나, 수치해석적 연구가 필요할 것으로 판단하였다. 선수 부가물은 Spray rail에서 착안하였으며, 구현이 쉽고 설계 파라미터를 제시 할 수 있는 Barge형상으로 적용하였다. 본 연구에서는 선수 부가물의 길이 변화에 따른 Axe Bow 선형의 Spray 억제를 수치해석적으로 고찰하였다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2010년도 하계학술대회 논문집
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• pp.68-68
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• 2010

To reduce PV manufacturing costs, the thickness of solar cell is getting thinner. Bow is shown after cooling down the temperature of solder cell. It happens because of different thermal expansion coefficients of different metals. Bowed cell can make micro crack while module processing and it can drop off efficiency of PV module. As thinner solar cell is produced, the thickness of ribbon should be concerned to prevent extra bow. In this paper we investigate the contrast of deflection when we solder different thickness of ribbons on same solar cell. This approach would help to find out the optical thickness of ribbon for particular thickness of solar cell later on.

• Journal of Mechanical Science and Technology
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• 제14권4호
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• pp.448-455
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• 2000

The bow wave breaking and the viscous interaction of stern wave are studied by simulating the free-surface flows. The Navier-Stokes equation is solved by a finite difference method in which the body-fitted coordinate system, the wall function and the triple-grid system are invoked. After validation, the calculations are extended to turbulent flows. The wave elevation at the Reynolds number of $10^4$ is much less than that at $10^6$ although the Froude number is the same. The numerical appearance of the sub-breaking waves is qualitatively supported by experimental observation. They are also applied to study the stern flow of S-103 for which extensive experimental data are available. Although the interaction between separation and the stern wave generation are not yet clear, the effects of the bow wave on the development of the boundary layer flows are concluded to be significant.

• Journal of electromagnetic engineering and science
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• 제4권1호
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• pp.13-16
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• 2004

In this paper, FDTD analysis of the bow-tie antenna is investigated by incorporating static field solution that is suitable to the bow-tie antenna without increasing computational time. Transforming static feld solution to the rotated grid system, we can obtain the transformed static field solution which is able to represent field behavior near the oblique edge line of the bow-tie antenna. The result shows a good agreement with a MoM analysis and is compared conformal modeling technique and regular FDTD method.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2001년도 추계종합학술대회
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• pp.210-213
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• 2001

본 논문에서는 광대역 동작을 위한 나비형 안테나의 임피던스 특성을 분석했다. 펄스 표면하 레이더는 지중 매설물에 대한 정보를 수집하기 위하여 임펄스를 사용하므로, 이러한 임펄스의 광대역 특성으로 인하여 급전점에서 발생하는 반사를 최소화할 수 있도록 광대역 정합 특성을 가진 안테나가 사용되어진다. 따라서, 본 논문에서는 광대역 특성을 가지는 나비형 안테나를 Ensemble 5.0으로 분석하였다.

• Nuclear Engineering and Technology
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• 제28권3호
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• pp.331-338
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• 1996

In the thermal-hydraulic design, the effect of fuel rod bow is quantified tv the rod bow DNBR penalty which is a key design parameter to assure the coolability of fuel assembly in the pressurized water reactor. In this work, a computer program for the evaluation of the rod bow DNBR penalty based on Westinghouse methodology is developed and its application procedure is proposed. The computer simulation is based on the Monte-Carlo method. The qualification of developed computer program is performed by a comparison of calculational result with that given by Westinghouse's document. A new application procedure is built using batch mean and batch standard deviation. The normality of sample population generated by the batch calculation is confirmed by means of a chi-square test for goodness of fit. On the view point of statistics it is effected that the more reliable design value may be produced by the new application procedure.

• International journal of advanced smart convergence
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• 제7권4호
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• pp.108-113
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• 2018

In this study, we introduce a new image gradient computation based on understanding of image generation. Most images consist of groups of pixels with similar color information because the images are generally obtained by taking a picture of the real world. The general gradient operator for an image compares only the neighboring pixels and cannot obtain information about a wide area, and there is a risk of falling into a local minimum problem. Therefore, it is necessary to attempt to introduce the gradient operator of the interval concept. We present a bow-tie gradient by color values of pixels on bow-tie region of a given pixel. To confirm the superiority of our study, we applied our bow-tie gradient to image segmentation algorithms for various images.

• Journal of Advanced Research in Ocean Engineering
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• 제4권4호
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• pp.204-216
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• 2018

A ship repeatedly face free surface under rough sea conditions owing to relative motion with wave encounter. The impact pressure is transferred to the hull structure and causes structural damage. In this study, the bow flare slamming load of a container ship is estimated using computations fluid dynamics (CFD) and prescript formula according to various classifications. It is found that the bow flare slamming load calculated by the formulas of the common structural rule and ABS tends to be similar to the CFD results.