• Proceedings of the Korea Water Resources Association Conference
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• 2017.05a
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• pp.115-115
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• 2017

남한강에는 4대강 사업으로 바닥 준설과 함께 3개의 보가 건설되었으며 이들의 영향으로 흐름 특성에 많은 변화가 발생하였다. 따라서 사업 이전 환경에 대해 개발된 수위-유량 관계식은 보의 배수위 영향과 준설로 변화된 단면 형상으로 인해 더 이상 사용할 수 없는 실정이다. 본 연구에서는 보의 운영을 고려한 수위-유량 관계식을 개발하는 방법에 대해 제시하고 이를 남한강에 적용하여 강천보와 여주보 사이에 위치한 여주관측소 지점에 대해 개도별 수위-유량 관계식을 개발하였다. 수위, 유량 등의 흐름 특성은 보의 운영을 고려할 수 있는 부정류 계산모형에 의해 모의되었다. 2000년도에 발생한 홍수사상 중에서 규모가 다양한 10개 홍수사상을 선정하고 입력 자료를 구성하였으며, 이 중 5개는 관계식을 도출하는데, 나머지 5개는 검증하는데 사용하였다. 수위, 유량, 보의 개도 등은 매 시간 모의되었으며, 모의된 수위-유량 페어는 보의 개도에 따라 분류되었다. 이는 배수위 등의 영향으로 인해 수위와 유량이 고유한 관계를 갖지 못한다는 것을 의미하며 보의 개도를 고려해야만 정확한 관계식을 도출할 수 있다는 것을 뜻한다.

• Proceedings of the Korea Contents Association Conference
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• 2019.05a
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• pp.371-372
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• 2019

금속 3D 프린팅의 응용분야는 자동차, 우주항공, 의료/헬스, 전자기기, 금형 등으로 분류할 수 있다. 최근 들어 선진국을 중심으로 아크 용접기반 금속 3D 프린팅 기술의 연구개발이 활발히 진행되고 있다. 3D 프린팅 기술은 CAD 설계 정보를 이용한 적층 제조방식이기 때문에 내부 형상이 아무리 복잡하여도 제작이 가능하고, 디자인이 변경되더라도 별도의 금형 제작 없이 제작이 가능하다는 장점이 있다. 와이어 아크기반 금속 3D 프린팅 기술은 차세대 생산제조 핵심기술로 발전할 전망이다. 금속 3D 프린터의 기술경쟁력 제고를 위해서 적층패턴, 와이어정밀 송급 및 적층품질 실시간 모니터링 등의 시스템 제어 기술과 대형 금속부품의 고생산성을 위한 적층가공 시스템 기술개발이 진행될 것으로 예상된다. 금속 와이어 아크를 이용한 대형 3D 프린팅 시스템의 지식재산권 확보 전략을 수립하기 위해 대형 3D 프린터 기술, 금속 와이어 3D 프린터 기술, 아크 3D 프린터 기술의 세 가지 분야에 대한 특허동향 분석을 수행하였다.

• Broadcasting and Media Magazine
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• v.26 no.3
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• pp.59-70
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• 2021

미래의 메타버스 환경에서 3차원 가상 휴먼 표현은 매우 중요한 기술이며 영상 또는 비디오로부터 3차원 가상 휴먼 모델링이 핵심 기술이다. 본 기고문은 이 분야에 대한 충분한 사전 지식의 제공을 목표로 한다. 휴먼 복원 문제를 다루는 연구가 늘어남에 따라, 본 기고문에서 우리는 단일 영상 혹은 비디오로부터의 3차원 휴먼 복원 연구들에 대해 조사하고 그 결과를 다음과 같이 체계적으로 제시한다. 첫째, 3차원 휴먼 복원에 대한 배경 개념을 정의한다. 둘째, 제안된 분류법, 기여도, 정량적 결과에 따라 기존의 방법들을 상세하게 분석한다. 셋째, 관련 데이터셋 및 정성적 결과를 요약하여 연구자들이 이를 쉽게 활용할 수 있도록 한다. 마지막으로, 우리는 각 연구들을 분석하여 해당 방법들의 장점과 약점을 제시한다.

• Progress in Superconductivity and Cryogenics
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• v.10 no.1
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• pp.32-36
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• 2008

An HTS conductor with parallel HTS tapes is essential for a large power HTS device to flow a large current. One of the most important factor for this conductor is a current distribution. Non-uniform current distribution in parallel tapes makes the critical current of the conductor low and the AC losses high. In this paper we proposed a non-contact method which measured each current in parallel tapes by using an array of Hall sensors. A matrix can be derived from this array for calibration. The current distributions of 4 and 6 parallel tapes were measured.

• Annual Conference of KIPS
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• 2021.11a
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• pp.637-639
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• 2021

인공지능 기반의 생활폐기물의 인식 및 선별에서, 선별 정확도의 저하는 인식 대상의 형태적 다양성과 학습데이터 부족 및 불균등성에 기인한다. 본 연구에서는 비전 인공지능 기반의 효과적인 폐기물 선별을 위한 인식 시스템 및 감독학습 기반의 인공지능 학습 기법을 제안한다. 생활폐기물 중 순환자원적 가치가 높은 CAN, PET, 그리고 이와 형상적으로 유사한 폐기물에 대해 본 연구에서 제안된 시스템에서 물체원형 및 훼손된 형태의 총 18 종 이미지 데이터를 대상으로, 감독학습기반의 인공지능 모델 제작에서 최적의 데이터 레이블링을 위한 분류체계를 제시한다.

• Journal of the Korean Society for Precision Engineering
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• v.12 no.11
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• pp.148-158
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• 1995

This paper describes a hierarchical structure for feature definition and classification, and feature representation method based on frame structure for process planning of prismatic machined components of injection mold. The concept of Volume Removal Directions and Vertical Faces is proposed to develop a method to define and to classify features for components of injection mold systematically. A method for classifying features by the combination of volume removal directions and vertical faces is developed, and also a feature representation method by using frame structure to represent design and manufacturing information is presented.

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.11
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• pp.2150-2158
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• 1992

This study was carried out to investigate the flow structure and mixing process of a cross mixing flow formed by two round jets with respect to the ratio of mass flow rate. This flow configuration is of great practical relevance in a variety of combustion systems, and the flow behaviour of a cross jet defends critically on the ratio of mass flow rate and the cross angle. The mass flow rate ratios of two different jets were controlled as 1.0, 0.8, 0.6, and 0.4, and the crossing angle of two round jets was fixed at 45 degree. The velocities issuing from jet nozzle with an exit diameter of 20mm were adjusted to 40m/s, 32m/s, 24m/s, and 16m/s, and the measurements have been conducted in the streamwise range of $1.1X_0$to $2.5X_0$ by an on-line measurement system consisted of a constant temperature type two channel hot-wire anemometry connected to a computer analyzing system. The original air flow was generated by a subsonic wind tunnel with reliable stabilities and uniform flows in the test section. For the analysis of the cross mixing flow structure in the downstream region after the cross point, the mean velocity profiles, the resultant velocity contours, and the three-dimensional profiles depending upon the mass flow rate ratio have been concentrately studied.

• Journal of the Korean Institute of Intelligent Systems
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• v.21 no.6
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• pp.749-754
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• 2011

In this study, we propose the design of optimized pRBFNNs-based face recognition system using two-dimensional Image and ASM algorithm. usually the existing 2 dimensional face recognition methods have the effects of the scale change of the image, position variation or the backgrounds of an image. In this paper, the face region information obtained from the detected face region is used for the compensation of these defects. In this paper, we use a CCD camera to obtain a picture frame directly. By using histogram equalization method, we can partially enhance the distorted image influenced by natural as well as artificial illumination. AdaBoost algorithm is used for the detection of face image between face and non-face image area. We can butt up personal profile by extracting the both face contour and shape using ASM(Active Shape Model) and then reduce dimension of image data using PCA. The proposed pRBFNNs consists of three functional modules such as the condition part, the conclusion part, and the inference part. In the condition part of fuzzy rules, input space is partitioned with Fuzzy C-Means clustering. In the conclusion part of rules, the connection weight of RBFNNs is represented as three kinds of polynomials such as constant, linear, and quadratic. The essential design parameters (including learning rate, momentum coefficient and fuzzification coefficient) of the networks are optimized by means of Differential Evolution. The proposed pRBFNNs are applied to real-time face image database and then demonstrated from viewpoint of the output performance and recognition rate.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.41 no.1
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• pp.47-55
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• 2023

In this study, the following conclusions were drawn by analyzing the size, proportion, shape, angle, distribution, etc. of stones in order to identify the principles of facade molding of stonework of the 5th to 7th centuries of the Silla Dynasty. First, the uniformity of the size of the stones of the stone foundations of the Silla Dynasty was low at -0.8 to 4.1. This means that stones of various sizes were used, from small stones to large stones. In addition, the distribution of large stones in stonework of the Silla Dynasty appeared evenly regardless of height. This was common in the stonework of the Silla Dynasty, regardless of structural classification such as wells and mountain fortresses. It is thought that the Silla people did not only pursue practicality and efficiency in stone construction, but also considered design elements. Second, the proportional deviation of the stones of the stone walls of the Silla Dynasty was high, ranging from 0.861 to 1.515. This means that the stonework of the Silla Dynasty did not use only long flagstone-shaped stones, but used a mixture of long and short stones. Third, the shape average of the stones of the stonework of the Silla Dynasty was low at 0.45, and the shape deviation was high at the maximum of 0.15. This means that the stones as a whole have irregular shapes, and each stone has a high difference in shape. Fourth, the angle deviation of the stones of the Silla Dynasty was 4.3 to 16.2, and the average angle was 2. This means that the angle of each stone on the stone axis of the Silla Dynasty is tilted to the left and right. Fifth, there was no correlation between stone size, slenderness ratio, shape, and angle in the stone axes of the Silla Dynasty. In the case of stone axes in the Joseon Dynasty, there was a positive correlation between stone size and slenderness, and a negative correlation between stone size and shape. It can be said that the stones of the Joseon Dynasty were relatively standardized, but the Silla Dynasty showed the beauty of moderation by keeping the nature of the material and becoming one with the material.

• Journal of the Earthquake Engineering Society of Korea
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• v.11 no.1 s.53
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• pp.45-57
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• 2007

The mean shear wave velocity to the depth of 30 m (Vs30) derived from the western Vs is the current site classification criterion for determining the design seismic ground motion taking into account the site amplification potential. In order to evaluate the Vs30 at a site, a shear wave velocity (Vs) Profile extending to at least 30 m in depth must be acquired from in-situ seismic test. In many cases, however, the resultant depth of the Vs profile may not extend to 30 m, owing to the unfavorable field condition and the limitation of adopted testing techniques. In this study, the Vs30 and the mean shear wave velocity to a depth shallower, than 30 m (VsDs) were computed from the Vs profiles more than 30 m in depth obtained by performing various seismic tests at total 72 sites in Korea, and a correlation between Vs30 and VsDs was drawn based on the computed mean Vs data. In addition, a method for extrapolating the Vs profile from shallow depth to 30 m was developed by building a shape curve based on the average data of all Vs profiles. For evaluating the Vs30 from the shallow Vs profiles, both the methods using VsDs and shape curve result in less bias than the simplest method of extending the lowermost Vs equally to 30 m in depth, and are usefully applicable particularly in the cases of the Vs profiles extending to at least 10 m in depth.