주 객체 위치 검출을 위한 Grad-CAM 기반의 딥러닝 네트워크

김선진,이종근,곽내정,류성필,안재형,Kim, Seon-Jin,Lee, Jong-Keun,Kwak, Nae-Jung,Ryu, Sung-Pil,Ahn, Jae-Hyeong 한국정보통신학회 2020 한국정보통신학회논문지 Vol.24 No.2

본 논문에서는 약한 지도학습을 통한 주 객체 위치 검출을 위한 최적의 딥러닝 네트워크 구조를 제안한다. 제안된 네트워크는 약한 지도학습을 통한 주 객체의 위치 검출 정확도를 향상시키기 위해 컨벌루션 블록을 추가하였다. 추가적인 딥러닝 네트워크는 VGG-16을 기반으로 합성곱 층을 더해주는 5가지 추가적인 블록으로 구성되며 객체의 실제 위치 정보가 필요하지 않는 약한 지도 학습의 방법으로 학습하였다. 또한 객체의 위치 검출에는 약한 지도학습의 방법 중, CAM에서 GAP이 필요하다는 단점을 보완한 Grad-CAM을 사용하였다. 제안한 네트워크는 CUB-200-2011 데이터 셋을 이용하여 성능을 테스트하였으며 Top-1 Localization Error를 산출하였을 때 50.13%의 결과를 얻을 수 있었다. 또한 제안한 네트워크는 기존의 방법보다 주 객체를 검출하는데 더 높은 정확도를 보인다. In this paper, we propose an optimal deep learning network architecture for main object location detection through weak supervised learning. The proposed network adds convolution blocks for improving the localization accuracy of the main object through weakly-supervised learning. The additional deep learning network consists of five additional blocks that add a composite product layer based on VGG-16. And the proposed network was trained by the method of weakly-supervised learning that does not require real location information for objects. In addition, Grad-CAM to compensate for the weakness of GAP in CAM, which is one of weak supervised learning methods, was used. The proposed network was tested through the CUB-200-2011 data set, we could obtain 50.13% in top-1 localization error. Also, the proposed network shows higher accuracy in detecting the main object than the existing method.

피로균열전파저항의 변동성에 의한 균열전파율의 해석

김선진,Kim, Seon-Jin 대한기계학회 1999 大韓機械學會論文集A Vol.23 No.7

Reliability analysis of structures based on fracture mechanics requires knowledge on statistical characteristics of the parameter C and m in the fatigue crack growth law, $da/dN=C({\Delta}K)^m$. The purpose of the present study is to investigate if it is possible to predict fatigue crack growth rate by only the fluctuation of the parameter C. In this study, Paris-Erdogan law is adopted, where the author treat the parameter C as random and m as constant. The fluctuation of crack growth rate is assumed only due to the parameter C. The growth resistance coefficient of material to fatigue crack growth (Z=1/C) was treated as a spatial stochastic process, which varies randomly on the crack path. The theoretical crack growth rates at various stress intensity factor range are discussed. Constant ${\Delta}K$ fatigue crack growth tests were performed on the structural steel, SM45C. The experimental data were analyzed to determine the autocorrelation function and Weibull distributions of the fatigue crack growth resistance. And also, the effect of the parameter m of Paris' law due to variation of fatigue crack growth resistance was discussed.

S45C 강의 피로균열전파 지연거동의 영향인자에 관한 실험적 연구

김선진,안석환,Kim, Seon-Jin,An, Seok-Hwan 대한기계학회 2001 大韓機械學會論文集A Vol.25 No.3

Constant ΔK fatigue crack growth tests were performed by applying an intermediate multiple overload for S45C steel. The purpose of the present study is to investigate effects of specimen thickness at various baseline stress intensity factor range levels (ΔK(sub)b), overload application position (a/W) and overload application frequency (OL(sub)HZ) on fatigue crack growth retardation behavior. The principal results are summarized as follows. The amount of retardation for a given ΔK(sub)b level is increased with increasing the baseline stress intensity factor range level for all specimen thickness. The normalized minimum crack growth rate is increased with increasing the specimen thickness, except for ΔK=45MPa√m. The retardation cycle is decreased with increasing a/W and increased with OL(sub)HZ.

플라스틱 가공제품 제조업의 작업환경 및 건강관리

김선진,Kim, Seon-Jin 대한산업보건협회 2005 산업보건 Vol.203 No.-

와이블 통계 해석에 의한 ZrO₂ 복합 세라믹스의 기계적 특성

김선진,김대식,남기우,Kim, Seon Jin,Kim, Dae Sik,Nam, Ki Woo 대한기계학회 2015 大韓機械學會論文集A Vol.39 No.10

비커스 경도 시험은 모든 재료에 적용할 수 있으며, 경도 시험 중에서 가장 광범위하게 사용된다. 경도는 기계적 성질을 평가하는 하나의 확률변수로 볼 수 있다. 본 연구는 $ZrO_2$ 단상 세라믹스와 $TiO_2$ 첨가량에 따르는 $ZrO_2/SiC$ 복합 세라믹스의 굽힘강도와 비커스 경도의 통계적 성질을 조사하였다. 굽힘강도와 비커스 경도는 와이블 확률 분포를 잘 따랐다. 척도 및 형상 파라메터는 $ZrO_2$ 모재 세라믹스, $ZrO_2/SiC/TiO_2$ 모재 세라믹스 및 이들을 열처리한 세라믹스를 사용하여 평가하였다. 또한 압입하중의 증가에 따른 영향도 평가하였다. The Vickers test can be used for all types of materials, and it has one of the widest scales among hardness tests. The hardness may be considered as a probability variable when evaluating the mechanical properties of materials. In this study, we investigate the statistical properties of the bending strength and Vickers hardness in $ZrO_2$ monolithic and $ZrO_2/SiC$ composites depending on the amount of $TiO_2$ additives. The bending strength and Vickers hardness were found to agree well with the Weibull probability distribution. We evaluate the scale parameter and shape parameter in as-received $ZrO_2$ and $ZrO_2/SiC/TiO_2$ ceramics, as well as their heat treated ceramics. We also evaluate the parameters in accordance with the increase in in the indentation load.

탄소섬유강화 복합재료 강도데이터의 통계적 특성에 관한 연구

김선진,이상국,남기우,오세규,Kim, Seon-Jin,Lee, Sang-Guk,Nam, Ki-Woo,Oh, Sae-Kyoo 대한기계학회 1996 大韓機械學會論文集A Vol.20 No.2

An investigation was conducted to study the statistical nature of tensile strength and static fracture toughness of carbon fiber reinforced plastics(CFRP) materials. A good understanding of statistical aspects of strength data is essential for the successful application of such materials because these composites unpossess material uniformity as compared with conventional metallic materials. In this paper, a statistical approach based on Weibull distribution was applied to the test data to evaluate the dispersion in the tensile strength and static fracture toughness by the change of stacking method and test temparature of the CFRP materials.

자신의 목소리 찾기: 『릴라이어블이라는 이름의 택시』에 나타난 갈등과 성장의 이야기

손정희 ( Jeong Hee Sohn ),김선진 ( Seon Jin Kim ) 한국영미문화학회 2008 영미문화 Vol.8 No.2

패스(Path)제어 방법을 통한 NSD 소음 저감 방안에 관한 연구

김선진(Seon-Jin Kim),김성곤(Sung-Gon Kim),강태우(Tae-Woo Kang),신철호(Cheol-Ho Shin) 한국산학기술학회 2018 한국산학기술학회논문지 Vol.19 No.10

본 연구는 패스(Path) 제어방법을 적용하여 소형전술차량에 적용된 NSD의 소음을 저감하기 위한 것이다. 소형전술차량은 고기동성 확보를 위해 후차축에 차동제한장치 중 하나인 NSD를 적용하였다. NSD는 높은 제한율을 가져 기동성을 향상 시켜주지만 기계적 구조에 의해 특정 조건에서 소음이 발생되는 단점이 있다. 이 소음은 NSD가 차동장치로써 원활한 역할수행을 위해 기어간 유격에 의해 치간 접촉에 따라 발생되는 소음이다. 이러한 소음이 지속적으로 사용자에게 전달됨에 따라 운용자가 지속적인 문제 제기 및 개선 요구를 하고 있다. 물론, NSD의 소음으로 인해 제품의 성능 또는 내구성에 미치는 영향은 없으며, 국방규격에서 규정하는 소음 조건 역시 만족한다. 하지만, 사용자의 지속적인 개선요구에 따라 소음저감을 위한 방안에 대해 연구를 수행하였다. 따라서, 본 연구에서는 소음원의 제거가 현실적으로 제한되는 전술차량의 NSD 소음을 감소하기 위해 NSD의 소음이 전달되는 경로를 제어하는 패스제어방법을 적용하였다. 이를 통해 구조 전달계를 개선•보완하고 이에 대한 개선효과를 검증하고자 한다. This paper presents means of reducing noise in NSD using path control methods for Light Tactical Vehicles (LTV). NSD is applied to the rear axle of LTVs for enhancing mobility. NSD can improve mobility of vehicles with a high locking ratio but causes noise under certain conditions due to its mechanical structure. This noise results from contact between gears due to the differential role of NSD. The noise affects users, so users have continually requested noise reductions. Though the noise doesn"t affect product performance and durability, and satisfies the National Defense"s noise condition standards, users request for noise reduction is the focus of this research. Eliminating the source of sound for LTVs is realistically limited, so this research applies a path control method to reduce noise by controlling the path which transmits the noise. This study improves the structural delivery system and examines methods of reducing noise in LTV systems.

저사이클 피로 영역에서의 Alloy 617 모재와 용접재의 파괴시험편에 대한 거시적 및 미시적 관찰

김선진(Seon Jin Kim),랜도 디와(Rando Tungga Dewa),김영식(Yeong Sik Kim),김우곤(Woo Gon Kim),김응선(Eung Seon Kim) 대한기계학회 2015 대한기계학회 춘추학술대회 Vol.2015 No.11

This paper presents the macro and microscopic fractography performed on fracture specimens from low cycle fatigue testings through Alloy 617 base metal and weldments. The weldment specimens were taken from GTAW pad of Alloy 617. The aims of the present study are to investigate the macro and microscopic aspects of low cycle fatigue fracture mode and mechanism of Alloy 617 base metal and the GTAWed weldment specimens. Fully axial total strain controlled tests had conducted at room temperature with total strain ranges of 0.6, 0.9, 1.2 and 1.5%. Macroscopic fracture surfaces of Alloy 617 base metal specimens showed a flat type normal to fatigue loading direction, whereas the GTAWed weldment specimens showed relatively shear/star type. The fracture surfaces of both the base metal and weldment specimens revealed the obvious fatigue striations at crack propagation regime. In addition, the fatigue crack initiation mechanism of the base metal showed a transgranular normal to fatigue loading direction, however, the GTAWed weldment specimens showed a transgranular about 45 degrees to fatigue loading direction.

마찰교반용접된 AA7075-T651 판재의 피로균열전파저항의 공간적 불규칙성에 미치는 초기균열위치의 영향

김선진(Seon Jin Kim) 대한기계학회 2014 대한기계학회 춘추학술대회 Vol.2014 No.5

In the present paper, the effects of initial crack location on spatial randomness of fatigue crack growth resistance (FCGR) in friction stir welded (FSWed) AA7075-T651 plates were studied. The objective of this study is to characterize the statistical properties of FCGR for three different types of initial crack location (ICL) specimens. In this work, the FCGR coefficients are treated as a spatial random process. It was found that the FCGR coefficients for all initial crack location specimens was well followed 2-parameter Weibull distribution. The shape parameter for BM-ICL specimens showed the largest value, WM-ICL specimens showed the smallest value. And also, the autocorrelation functions for all specimens were well followed the exponential function.