• Journal of Korea Society of Industrial Information Systems
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• v.19 no.4
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• pp.41-52
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• 2014

In this paper, O-ring size measurement algorithm based on a small machine vision inspection equipment which can replace a expensive and large machine vision inspection equipment is presented. The small machine vision inspection equipment acquires a image from a CCD camera shooting a measurement plane which located on a back light and the proposed size measurement algorithm is apply to the image. For improvement of size measurement accuracy, camera lens distortion correction and perspective distortion correction are conducted by software technique. Consider O-ring's shape, ellipse fitting model is applied. In order to increase the reliability of ellipse fitting, RANSAC algorithm is applied.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.220-220
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• 2022

물관리 일원화, 물관리기본법 제정·시행 등 우리나라 물관리 체계의 혁신기에 정책의 구심점 역할을 수행할 통합 물관리 전략 마련이 요구됨에 따라, 최근 관계부처 합동으로 「제1차 국가물관기본계획(2021~2030)」을 수립하여 공표·발간되었다. 국가물관리기본계획에서는 유역단위의 물관리를 원칙(12대 기본원칙 중(中))로 하며, 물관리 3대분야(수질·수생태, 이수, 치수)에 대한 추진전략을 수립하였다. 또한, 지속가능한 물관리 체계를 구축하기 위해 추진전략별 주요 관리지표를 설정하였으며, 이를 통해 물관리 방향을 정립하고 분야별 관련 및 하위계획과의 일관성·정합성을 유지하고자 하였다. 이에 본 연구에서는 추진전략별 주요 관리지표 중, 유역 재해안전도와 관련하여 하천범람에 대한 기존의 치수안전도의 한계점을 검토하고 유역단위의 치수관리 현황을 평가 할 수 있는 방안을 마련하고자 하였다. 과거 유역종합치수계획에서의 치수안전도는 홍수피해잠재능(PFD)을 적용하여 등급별 홍수방어대책 수립방향 및 하천의 설계빈도 조정을 검토하였으며, 홍수피해잠재능(PFD)의 실무적 적용 어려움(산정인자 다(多)), 설계빈도와의 연계성 부족, 치수단위구역의 공간적 정확성 미흡 등에 대한 개선·보완의 의견이 제기되어 왔다. 또한, 유역내 전체하천이 아닌 주요 하천을 대상으로만 치수안전도 설정하여 유역단위의 치수관리에 한계가 있으며, 하천 전체구간의 설계빈도 상향에 따른 홍수방어대책이 비경제적인 것으로 판단된다. 따라서, 기존의 치수안전도의 한계점을 개선하기 위하여 홍수피해잠재능(PFD)의 산정인자 단순화, 홍수위험지도를 활용을 통한 치수단위구역의 공간적 정확도 향상 및 치수단위구역별 설계빈도 조정 가능 등의 개선방안을 검토하였으며, 빈도별 치수단위구역의 홍수피해잠재능(PFD)의 통계적 특성 분석을 통해 등급 설정 및 설계빈도 조정 기준을 제시하였다. 그리고 유역내 전체하천에 대한 치수단위구역별 치수안전도를 설정하고, 중권역 단위의 치수안전도를 평가하여 유역단위의 치수관리 현황을 정량적으로 제시함에 유역 재해안전도로 활용이 가능할 것으로 판단된다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.12
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• pp.1086-1096
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• 2011

In this paper, we present the trisection band-pass filter with a transmission zero at 2.63 GHz, which has a center frequency of 2.44 GHz, relative bandwidth of 5 %, and return loss of 18 dB, based on a multi-port ElectroMagnetic simulation. The coupling matrix for the trisection filter is calculated and this filter is transformed into band-pass filter prototype through a lossless 2-port circuit transformation. The J-inverter values and slope parameters of each individual resonator are computed using an EM simulation Y-parameters of the filter with multi port. The dimensions of desired filter are determined by matching the computed J-inverter and susceptance slope parameters to those of the prototype band-pass filter. Undesired cross-couplings are found to occur which does not appear in the prototype trisection filter. To overcome the problem of undesired couplings, the filter was optimized to satisfy the same frequency response of prototype filter. The validity of the proposed design method was verified through the implementation of the designed and optimized filter.

• Journal of Ocean Engineering and Technology
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• v.32 no.2
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• pp.106-115
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• 2018

The forward and afterward parts of ships and offshore structures are designed to improve the fuel consumption performance. These are made of curved plates with a large thickness. If a fabricated curved plate has some dimensional errors, a lot of additional cost is incurred in the assembly process. Thus, an accurate dimensional assessment is very important for fabrication. In this paper, we propose an assessment method for the dimensional quality management of curved plates. This can be applied to data measured using a variety of three-dimensional instruments, with boundary measurement points automatically classified and sorted to create a measurement surface. The assessment is evaluated after matching the CAD surface and the measured surface considering constrained conditions. The fabrication assessment is evaluated as a probability of how much the tolerance is satisfied.

• Korean Journal of Computational Design and Engineering
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• v.21 no.2
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• pp.151-158
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• 2016

It is important to analyze dimensional errors occurring during shipbuilding process. A ship is constructed by assembling blocks and installing outfits in assembled ship structure. Blocks and outfits have a main direction that has greater importance than other directions from the view point of dimensional error. Therefore, a main direction should have a greater weighting factor than other directions in order to achieve meaningful inspection results. In this paper, a modified point registration method based on iterative closest point (ICP) is proposed. In this method, a user determines one or two main directions among x, y, and z directions, and then each main direction is made to have a greater weighting factor than other directions. For points registration, mapping between measured points and design points are performed by the modified ICP in which weighting factor assigned to each main direction is considered.

• Journal of the Korean Wood Science and Technology
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• v.23 no.4
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• pp.85-90
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• 1995

목질보드 제조에 있어 매트의 최종함수율은 에너지가 필요한 목질 엘리먼트의 초기 건조공정이나 열압싸이클공정, 목질보드의 균질정합성, 목질재료의 물리 기계적 성질 및 치수안정에 지대한 영향을 주기 때문에 대단히 중요하다. 지금까지 PB에 대한 최종매트의 함수율에 대한 연구는 많이 보고되어 있으나 요소수지로 제조되는 MDF에 대한 연구보고는 없으며 미국과 한국을 위시한 각국이 MDF의 최종함수율을 PB에 준하여 8~11%로 조정하여 MDF를 제조하고 있다. 따라서 본 연구는 미국산 침엽수 혼합수종으로부터 제조된 가압 해섬섬유와 요소수지로 제조된 MDF의 물리 기계적 성질에 관련된 적정 최종매트 함수율을 규명하고자 실시하여 다음과 같은 결론을 얻었다. 1. 혼합 침엽수 원료로부터 제조된 요소수지제조 MDF의 적정 최종 매트 함수율은 13% 부근으로서 현재 MDF공장에서 적용되고 있는 8~11%보다 높았다. 2 평판이 시작되는 최종매트 함수율은 15.4%였다.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.2
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• pp.134-140
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• 2009

In this paper, we discussed the trapezoidal antenna model in the microstrip structure for UWB communications in the frequency band of $3.1{\times}10.6GHz$. Through the computer simulations for the difference size of trapezoidal monopole microstrip antenna model, the good impedance matching characteristic of return loss less than -10dB(VSWR<2) in all the band of UWB showed. The optimized antenna of this paper also showed the quasi-isotropic radiation characteristics in the horizontal plane and linear phase characteristic of nondispersive property.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.15 no.3
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• pp.83-91
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• 2009

It is very difficult to export the fresh agricultural products to long distance countries such as USA and EU without any damage. Fresh products exporting would overcome very severe conditions such as hot and cold weather changes, heavy vibrations with rolling and pitching during the target distribution period, therefore, the packaging needs the immobility of products in the container and the keeping its quality by packaging materials or methods under any surrounding environments, especially. The physical strength of outer box should be designated according to its own characteristics for agricultural product packaging. Packaging dimension which would be fit to standard pallet is also very important factor to reduce the distribution cost. There have been many agricultural products researches for export packaging to the USA so far. However they have never got desirable results which enough to apply it in real. The main purpose of this research is to develop optimum compressive strength and optimum dimension of corrugated fiberboard box which would be used to USA export packaging of fresh melon as well as Japan.

• KIEAE Journal
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• v.13 no.6
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• pp.121-128
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• 2013

This study attempted to explore the MC design methods of modular construction using discontinuous double module grids and further, the design methods of walls. Modular construction is generally characterized with multiple units called modules with a module dimension of 3M(300mm) appearing in the form of double grids. The discontinuous double grids including correction values and gap values occurs inevitably in the modular construction where units are joined horizontally. Therefore, it is desirable to carry out the MC design taking into account these discontinuous double grids. In this study, the MC design was applied to the plane of wooden houses in modular construction, going through a process of setting the size of pillars and inside dimensions, of determining the dimension of discontinuous double grids that occur during the assembly of units, and of setting the dimension of outer walls in conjunction with the derived dimensions. The dimension of outer walls was applied differently depending on the range of regional use by analyzing the energy performance with the materials used. Consequently, the materials and components of factory-produced buildings can be used directly without processing, and the suitability of the outer wall design can be pre-determined by previewing the calculation of the cross-sectional configuration and heat transmission coefficients of outer walls in modular construction, allowing to be used as a decision-making tool of design.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.42 no.4
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• pp.798-805
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• 2017

This paper presents a low profile multi circular ring with different radius, patch antenna with modified feed line and slotted ground. The size of the antenna is $15{\times}12mm^2$, having electrical dimensions of $0.14{\lambda}{\times}0.12{\lambda}$ (at lower initial frequency) and footprints of $180mm^2$. The proposed antenna covers 3.1 to 12.3 GHz, reflection coefficient up to -38 dB with Bandwidth ratio of 4.13:1 and fractional Bandwidth of 122%. Bandwidth dimension ratio has been calculated (which is 6246) as a proof for compact size. Thin slots introduced on the feed line provide good impedance matching for whole frequency band. Numerical simulations of the proposed antenna are reported in terms of reflection coefficient ${\leq}-10dB$, vswr 2:1, radiation pattern and group delay (ns). The proposed antenna has advantage of very small size along with better impedance match that provides a practical approach to realize it for BW enhancement and UWB applications.