• 전기학회논문지
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• 제63권6호
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• pp.797-803
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• 2014

In this paper, 3D face recognition system is designed by using polynomial based on RBFNNs. In case of 2D face recognition, the recognition performance reduced by the external environmental factors such as illumination and facial pose. In order to compensate for these shortcomings of 2D face recognition, 3D face recognition. In the preprocessing part, according to the change of each position angle the obtained 3D face image shapes are changed into front image shapes through pose compensation. the depth data of face image shape by using Multiple Point Signature is extracted. Overall face depth information is obtained by using two or more reference points. The direct use of the extracted data an high-dimensional data leads to the deterioration of learning speed as well as recognition performance. We exploit principle component analysis(PCA) algorithm to conduct the dimension reduction of high-dimensional data. Parameter optimization is carried out with the aid of PSO for effective training and recognition. The proposed pattern classifier is experimented with and evaluated by using dataset obtained in IC & CI Lab.

• 디지털콘텐츠학회 논문지
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• 제8권4호
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• pp.459-465
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• 2007

본 논문에서는 다중 벽면 구조의 실내 환경에서 전파의 전달특성을 모델링하기 위해 ray-launching 기반의 광선추적법을 이용한 2차원 ray-tracing 시뮬레이터를 구현하였고, 이를 통해 ray의 전파 경로를 분석하고 평가하였다. 실험 결과, 구현된 광선추적법의 경로 패턴 및 시간지연 분포는 동일한 무선 환경에서 수행된 이전의 실험 결과와 비슷한 결과가 나타남을 확인하였으며, 송수신 거리 및 방사각에 따른 수신반경의 조정이 타당함을 확인하였다. 특히 비가시거리 송수신 환경에서 다중 벽면을 투과한 ray가 반사와 투과를 형성하여 수신기에 도달할 때까지의 ray의 impulse response는 기존 연구의 실험 결과와 대부분 일치하였으며, 송신기에서 발사되는 ray의 방사각을 $1^{\circ}$에서 $7^{\circ}$까지 달리하여 실험한 경우 도출된 channel profile이 서로 유사함을 확인하였다.

• 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.

• Earthquakes and Structures
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• 제13권2호
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• pp.211-220
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• 2017

Observations from past strong earthquakes revealed that near-fault ground motions could lead to the failure, or even collapse of electricity transmission towers which are vital components of an overhead electric power delivery system. For assessing the performance and robustness, a high-fidelity three-dimension finite element model of a long span transmission tower-line system is established with the consideration of geometric nonlinearity and material nonlinearity. In the numerical model, the Tian-Ma-Qu material model is utilized to capture the nonlinear behaviours of structural members, and the cumulative damage D is defined as an index to identify the failure of members. Consequently, incremental dynamic analyses (IDAs) are conducted to study the collapse fragility, damage positions, collapse margin ratio (CMR) and dynamic robustness of the transmission towers by using twenty near-fault ground motions selected from PEER. Based on the bending and shear deformation of structures, the collapse mechanism of electricity transmission towers subjected to Chi-Chi earthquake is investigated. This research can serve as a reference for the performance of large span transmission tower line system subjected to near-fault ground motions.

• 대순사상과 동아시아종교
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• 제1권1호
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• pp.103-125
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• 2021

This paper deals with figurative meanings of Haewon-sangsaeng. It is an investigation which is both semantic and diachronic. In the first part, important implications of sangsaeng (or xiangsheng in Chinese) in the context of correlative cosmology are extensively explored. Among others, saeng (in Chinese sheng) as a powerful metaphor and its related Chinese compounds are broadly discussed. In the second part, the evolution of ideas of yuan (or won in Korean) in Chinese history is explicated. Above all, in the traditional Chinese cultural milieu, wrongful treatments which make victims feel themselves aggrieved are socio-politically orientated. The Scripture on Great Peace (Taiping Jing) is used as reference point to elucidate the essential points of yuan and its knots. However, the advent of Buddhism in East Asia adds a new dimension to the understanding of yuan (won). Accumulated yuan as karmic bond thus gives a new identity of yuan as predetermined animosity. Widely recognized idioms like "adverse relatives and karmic debtors" and indigenous Chinese Buddhist rituals like Repentance Ritual of the Emperor Liang bear witness to this transformation of the meaning of yuan in East Asia. The fruitful yet correlated meanings of yuan also make the endeavor of untying yuan deeply significant and important to human society. Haewon-sangsaeng, as a religio-ethical ideal, brings out an amicable and harmonious relationship among myriad beings in the cosmos.

• Current Optics and Photonics
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• 제6권6호
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• pp.608-618
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• 2022

By analyzing the signal-to-noise ratio (SNR) theory of the conventional true color night vision system, we found that the output image SNR is limited by the wavelength range of the system response λ₁ and λ₂. Therefore, we built a double-channel four-band true color night vision system to expand the system response to improve the output image SNR. In the meantime, we proposed an image fusion method based on principal component analysis (PCA) and nonsubsampled shearlet transform (NSST) to obtain the true color night vision images. Through experiments, a method based on edge extraction of the targets and spatial dimension decorrelation was proposed to calculate the SNR of the obtained images and we calculated the correlation coefficient (CC) between the edge graphs of obtained and reference images. The results showed that the SNR of the images of four scenes obtained by our system were 125.0%, 145.8%, 86.0% and 51.8% higher, respectively, than that of the conventional tri-band system and CC was also higher, which demonstrated that our system can get true color images with better quality.

• Design & Manufacturing
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• 제15권4호
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• pp.8-13
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• 2021

A plastic roller for opening and closing the safety door of the injection molding machine was molded. The dimensional change of the measurement position of the roller was studied when the cooling time was applied differently among the molding conditions, and when the temperature of the coolant applied for mold cooling was also applied differently. Cooling times of 300 seconds and 400 seconds, hot and low-temperature coolant were applied. When the low-temperature coolant was applied, the measuring point of the roller shrank by 0.03 mm. However, when the high-temperature coolant was applied, the measuring point shrank by 0.3 mm. It was found that the application of low-temperature coolant among coolants was more suitable for the reference dimension of the molded article compared to the application of high-temperature coolant. Among the cooling water applied for the molding of plastic rollers, when high-temperature coolant is applied, the shrinkage rate measured immediately after ejection was smaller than when low-temperature coolant is applied. However, it was found that post shrinkage, which occurs over time, occurs much larger when high-temperature coolant is applied.

• Journal of Positioning, Navigation, and Timing
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• 제12권1호
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• pp.43-49
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• 2023

In modern wireless communication systems including beamformers or location-based services (LBS), which employ multiple antenna elements, estimating the number of signals is essential for accurately determining the quality of the communication service. Representative signal number estimation algorithms including the Akaike information criterion (AIC) and minimum description length (MDL) algorithms, which are information theoretical criterion models, determine the number of signals based on a reference value that minimizes each criterion. In general, increasing the number of elements mounted onto the array antenna enhances the performance of estimating the number of signals; however, it increases the computational complexity of the estimation algorithm. In addition, various configurations of array antennas for the increased number of antenna elements should be considered to efficiently utilize them in a limited location. In this paper, we introduce an efficient signal number estimation algorithm based on the beamspace based AIC and MDL techniques that reduce the computational complexity by reducing the dimension of a uniform circular array antenna. Since this algorithm is based on a uniform circular array antenna, it presents the advantages of a circular array antenna. The performance of the proposed signal number estimation algorithm is evaluated through computer simulation examples.

• 한국구조물진단유지관리공학회 논문집
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• 제21권1호
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• pp.91-99
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• 2017

본 논문은 폴리머 모르타르로 보수된 철근콘크리트 보의 휨거동을 실험적 해석적으로 분석한 결과를 제시한다. 실험적 연구에서는 보수위치, 모르타르 재령을 실험변수로 고려하여 제작된 13개의 보에 대한 3점 휨실험이 실시되었다. 인장측 및 압축측을 보수한 실험체들의 파괴는 모르타르와 콘크리트의 계면에서 발생하지 않았으며, 폴리머 모르타르의 인장변형률이 극한변형률을 초과하는 순간 발생하였다. 압축측을 보강한 실험체들은 기준실험체의 최대하중과 유사하였다. 그들의 연성지수는 기준실험체보다 훨씬 컸다. 인장측을 보수한 실험체는 매우 취성적으로 파괴되었으며, 연성지수가 크게 감소하였다. 폴리머 모르타르로 보수된 철근콘크리트의 보의 휨거동을 예측하기 위해 Opensees을 사용한 재료비선형 해석을 진행하였다. 해석 모델을 단순화하기 위해 2차원 골조요소를 적용하였으며, 재료 비선형성을 고려하기 위해 파이버 모델을 적용하였다. 해석결과는 비선형 구조해석은 압축측 보수 실험체의 휨거동을 적절하게 예측하나, 인장측 휨거동는 다소 과대 평가하는 것으로 나타났다.

• 농촌의학ㆍ지역보건
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• 제40권1호
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• pp.21-31
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• 2015

본 연구는 우리나라 성인 당뇨병환자의 삶의 질을 평가하고, 당뇨병이 다른 만성질환이나 정상 건강인에 비해 삶의 질이 얼마나 다른지 알아보고, 이에 영향을 미치는 요인들을 분석하고자 하였다. 연구의 대상자는 제5기(2010-2012) 국민건강영양조사 자료 중 건강 설문조사와 검진조사에 모두 응답한 자로서 분석 변수에 결측치가 없는 만 19세 이상 성인 17,655명으로 하였다. 만성질환군 및 정상 건강군에 비해 당뇨병환자에서 삶의 질의 모든 하부영역에 '문제 있다'라고 응답한 분율이 더 높았다. 당뇨병환자에서 삶의 질의 하부 영역 중 운동능력(36.4%)에 문제가 있다고 한 사람이 가장 많았으며, 그 다음으로 통증/불편감(35.4%)이었다. 당뇨병환자와 만성질환군 및 정상 건강군간 삶의 질의 5가지 하부 영역을 비교하기 위해 다중로지스틱회귀분석을 이용하여 당뇨병환자를 기준으로 '문제 있음'에 대한 교차비와 신뢰구간을 계산한 결과 운동능력은 당뇨병 환자에 비해 만성질환군의 OR(95%CI)값이 0.77(0.66-0.91), 정상 건강군이 0.61(0.50-0.75)이었고, 자기관리는 0.68(0.55-0.83), 0.69(0.51-0.94)이었고, 일상활동은 0.85(0.72-0.99), 0.79(0.62-0.98)로 당뇨병환자에 비해 만성질환군과 정상 건강군이 운동능력, 자기관리, 일상활동에 문제가 있을 가능성이 낮았다. 당뇨병환자의 질적인 삶을 영위하기 위해서는 삶의 질과 관련된 다양한 변인 연구들이 꾸준히 이루어져야 할 것이며, 삶의 질에 영향을 미치는 사회 인구학적, 건강관련 특성을 반영한 다양한 건강프로그램이나 복지정책을 개발, 발전하여 지속적으로 관리해야 한다고 사료된다.