온도범위에 따른 비침습적 자기공명 온도측정방법의 최적화

김종민,조영승,김정희,이철현,오창현,Kim, Jong-Min,Kumar, Suchit,Jo, Young-Seung,Park, Joshua Haekyun,Kim, Jeong-Hee,Lee, Chulhyun,Oh, Chang-Hyun 대한의용생체공학회 2015 의공학회지 Vol.36 No.6

Noninvasive temperature monitoring is feasible with Magnetic Resonance Imaging (MRI) based on temperature sensitive MR parameters such as $T_1$ and $T_2$ relaxation times, Proton Resonance Frequency shift (PRFs), diffusion, exchange process, magnetization transfer contrast, chemical exchange saturation transfer, etc. While the temperature monitoring is very useful to guide the thermal treatment such as RF hyperthermia or thermal ablation, the optimization of the MR thermometry method is essential because the range of temperature measurement depends on the choice of the measurement methods. Useful temperature range depends on the purpose of treatment methods, for example, $42^{\circ}C$ to $45^{\circ}C$ for RF hyperthermia and over $50^{\circ}C$ for thermal ablation. In this paper, MR thermometry methods using $T_1$ and $T_2$ relaxation times and PRFs-based MR thermometry are tried on a 3.0 T MRI system and their results are reported and compared. In addition, the scanning protocol and temperature calculation algorithms from $T_1$ and $T_2$ relaxation times and PRFs are optimized for the different temperature ranges for the purpose of RF hyperthermia and/or thermal ablation.

Nb함량에 따른 Cu-Nb나노복합재료의 기계적.전기적 특성

김종민,정진희,홍순익,Kim, Jong-Min,Jeong, Jin-Hui,Hong, Sun-Ik 한국재료학회 2001 한국재료학회지 Vol.11 No.4

The mechanical and electrical properties of Cu-Nb filamentary nanocomposite fabricated by the bundling and drawing process were examined. The strength increased gradually with increasing Nb content while the ductility was insensitive to Nb content. The ratio of yield stresses at 293K and 75K are found to be 치ose to that of Young's moduli in various Cu-Nb nanocomposites, suggesting that athermal obstacles primarily control the strength. The fracture morphologies show ductile fractures irrespective of Nb contents. Secondary cracking along the interfaces between subelemental wires was occasionally observed and the frequency of secondary cracking increased with increasing Nb content. The conductivity and the resistivity ratio decreased with increasing Nb content. The decrease of the conductivity and the resistivity ratio(${\rho}_{293k}$/$\{rho}_{75k}$) can be explained by the increasing contribution of interface scattering. 다발체 형성과 인발 공정으로 제조된 Cu-Nb 필라멘트 미세복합재료의 기계적 전기적 특성에 대하여 연구하였다. Nb의 함량이 증가함에 따라 강도는 점차 증가하였으나 연성은 Nb의 함량에 무관하였다. 293K와 75K에서의 항복강도의 비율은 Cu-Nb 미세복합재료의 Young의 계수 비율과 비슷하게 관찰되었다. 이러한 사실은 주로 장범위 방해물(athermal obstacles)들이 Cu-Nb 마세복합재료의 강도에 영향을 미친다는 것을 의미한다. 파면 조직관찰 결과는 Cu-Nb 미세복합재료는 Nb의 함량에 판관계없이 연성파괴의 특성을 나타내었으며, 부전선재 (subelematal wires)사이의 계면을 따라 발생하는 2차크랙 (secondary crack) 의 양은 Nb 함량이 증가함에 따라 증가하였다. 전기 전도도와 비저항비 (${\rho}_{293k}/{rho}_{75k}$)는 Nb 함량이 증가할수록 감소하였다. 이와 같은 Nb함량에 따른 전기전도도와 비저항비의 감소는 계면산란의 기여도가 증가하였기 때문이다.

CNN 방식과 전통적 방식의 스테레오 매칭 알고리즘 비교

김종민(Jong Min Kim),박정민(Jeong-Min Park),이준웅(Joon-Woong Lee) 제어로봇시스템학회 2020 제어·로봇·시스템학회 논문지 Vol.26 No.5

CNN has been widely used in computer vision. In particular, CNN has been applied in stereo matching, which involves finding pixels corresponding to each other in a pair of images that capture a scene at the same time. This paper focuses on analyzing stereo matching methods based on CNN, and compares them with a traditional stereo matching method. CNN-based methods produced good matching results for ill-posed areas, including textureless areas, repeated patterns and highly reflective surfaces. By contrast, traditional stereo matching methods could not produce good matching results for such ill-posed regions. Therefore, in this paper, we demonstrate how good CNN-based methods could produce matching results for both indoor and outdoor images.

수질관리 : 강우 및 유입하천수가 팔당호 수질에 미치는 영향분석

김종민 ( Jong Min Kim ),노혜란 ( Hye Ran Noh ),허성남 ( Seong Nam Heo ),양희정 ( Hee Jeong Yang ),황정 ( Jung Hwang ),정완종 ( Wan Jong Jeong ),이인선 ( In Seon Lee ) 대한상하수도학회 2002 공동추계 학술발표회 논문집 Vol.2002 No.-

차씨오일의 항산화 활성 및 뇌 해마유래 HT22 세포에서의 산화적 스트레스에 대한 보호효과

김종민(Jong Min Kim),박선경(Seon Kyeong Park),강진용(Jin Yong Kang),배성경(Seong-kyeong Bae),정가희(Ga-Hee Jeong),조경환(Kyoung Hwan Cho),김종철(Jong Cheol Kim),김재중(Jae Joong Kim),허호진(Ho Jin Heo ) 한국차학회 2018 한국차학회지 Vol.24 No.1

The antioxidant activities and hippocampal neuroprotective effects of tea (Camellia sinensis) seed oil against H 2 O 2 -induced oxidative stress were investigated to confirm its physiological effects. The antioxidant effects of tea seed oil were evaluated by measuring its 1,1-diphenyl-2-picrylhydrazyl, 2,2 -azino-bis (3-ethyl benzothiazoline-6-sulfonic acid) radical scavenging activities and malondialdehyde inhibitory effect. Tea seed oil was found to have significant antioxidant activity and inhibitory effect of lipid peroxidation. To confirm the ameliorating effect of the cholinergic system, the inhibitory effect of acetylcholinesterase (AChE) derived from PC12 was investigated. Tea seed oil was found to inhibit the AChE activity. Also, the protective effects of hippocampal neuronal cells against H 2 O 2 -induced neuronal cytotoxicity were investigated using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide and 2 ,7 -dichlor-ofluorescein diacetate in HT22 cells. Tea seed oil was found to significantly increase the cell viability and reactive oxygen species scavenging activity.

스테레오 영상처리 기반의 3차원 객체 검출을 위한 3차원 포인트 필터링 알고리즘

김종민(Jong-Min Kim),박정민(Jeong-Min Park),이준웅(Joon-Woong Lee) 제어로봇시스템학회 2021 제어·로봇·시스템학회 논문지 Vol.27 No.9

Unlike LIDAR-based 3D object detection algorithms, stereo-based 3D object detection algorithms have low performance. The main reason for this problem is the low accuracy of the 3D information predicted from stereo image processing. Inaccurate 3D information distorts the 3D shape of an object. Therefore, this study aims to improve the performance of the stereo-based 3D object detection algorithms by proposing a filtering algorithm that can filter out inaccurate 3D information. The filtering algorithm uses a 3D offset, which is the distance between a 3D point on an object and the center of gravity of the object. Since the object size is limited, the 3D offset length of the points constituting the object is always smaller than the object size itself. However, there is a case where the 3D offset length of inaccurate 3D information is larger than the object size. The proposed filtering algorithm filters out inaccurate 3D information to address this issue. This study experimentally proves that the filtering algorithm is effective in enhancing the stereo-based 3D object detection performance.

팔당호 수질의 계절별 변화특성 및 장기 추세

김종민(Jong Min Kim),허성남(Seong Nam Heo),노혜란(Hye Ran Noh),양희정(Hee Jeong Yang),임연택(Yeon Taek Lim),정완종(Wan Jong Jeong) 한국물환경학회 2002 한국물환경학회지 Vol.18 No.1

The long-term data (`88∼2000), which have been released by National Institute of Environmental Research (NIER) and Ministry of Construction and Transportation on the water quality and hydrological characteristics in Lake Paldang, were analyzed to find their monthly and annual variation tendency. Water volume tended to decrease during summer season, this phenomenon was assumed that dam authority might open the floodgate in advance to prevent an inundation. And DO saturation ratio exceeded 95% during ail seasons. That time, the concentration of chlorophyll-a (about 10㎎/㎥or higher) and T-P (about 0.03 ㎎/l or higher) denoted high level. Correlation between conductivity and COD denoted middle level (r=0.597, r²=0.36, p$lt;0.01). Conductivity denoted the minimum value in January and February, that was the coldest and freezing season in Lake Paldang. COD denoted the maximum value in June, whereas the inflow and pollutant load were high in July and August. Therefore It was assumed that the effect of dilution was stronger than that of pollutant load. T-N annual variation pattern of annual mean level was similar to COD pattern, but T-P denoted an opposite pattern to T-N. N:P mass ratio seemed to be more affected by T-P concentration than T-N. Annual mean level of N:P mass ratio tended to increased during 1991-2000. In June, transparency denoted the highest level and the concentration of chlorophyll-a & suspended solids denoted the lowest level. The relationship between transparency and suspended solids were relatively high (r=-0.6, r²=0.362, p$lt;0.01) than the relationship between transparency and chlorophyll-a (r=-0.269, r²=0.072, p$lt;0.01).

문맥 교환으로 인한 캐쉬 접근 실패를 줄이는 precharging 캐쉬 구조

김종민(Jong Min Kim),이민석(Minsuk Lee),박명순(Myung Soon Park),민상렬(Sang Lyul Min),정덕균(Deog-Kyoon Jeong),신현식(Heonshik Shin),김종상(Chong Sang Kim) 한국정보과학회 1994 정보과학회논문지 Vol.21 No.7

최근 캐쉬를 사용하는 고속의 프로세서들이 출현하면서 캐쉬 접근 실패를 처리하기 위해 소요되는 프로세서 싸이클 수가 전체 수행 시간에서 차지하는 비중은 계속해서 높아지고 있다. 특히 문맥 교환으로 인하여 발생하는 캐쉬 접근 실패는 캐쉬의 크기와 연관도가 증가할수록 전체 캐쉬 접근 실패의 많은 비중을 차지한다. 본 논문에서는 이러한 문맥 교환으로 인한 캐쉬 접근 실패를 줄일 수 있는 precharging 캐쉬 기법을 제안한다. 이 기법의 핵심은 프로세스가 문맥 교환되고 어느 정도의 시간이 지난 후에 발생되는 캐쉬와 메모리 사이의 유휴 메모리 대역폭을 이용하여 다음에 수행될 프로세스의 캐쉬 상태를 프로세스가 수행되기 이전에 미리 캐쉬에 읽어오는 것이다. 즉 캐쉬에서 해제된 각 블록들의 주소 정보와 프로세스 식별자를 이용하여 해당 프로세스가 수행되기 전에 미리 캐쉬에 필요한 블록을 적재하는 것이다. 이렇게 함으로써 해당 프로세스가 수행될 때에는 자신의 작업 집합(working set)이 이미 캐쉬 내에 존재하므로 다른 프로세스와의 캐쉬 블록 충돌에 의해 발생하는 접근 실패를 겪지 않는다. 본 논문에서 제시한 precharging 캐쉬 기법에 의한 성능 향상은 BACH 트레이스를 사용한 시뮬레이션으로 검증 하였으며, 그 결과 전체 발생하는 캐쉬 접근 실패의 0.68-9.52% 정도를 줄일 수 있고, 사용자 모드에서 발생하는 캐쉬 접근 실패의 2.81-15.3% 정도를 줄일 수 있음을 보였다. In current high-performance processors with cache memories, the relative cast of a cache miss in terms of processor cycles is becoming higher. As the size and set associativity of cache memory increase, the cache misses resulting from context switches take an increasingly large portion of total cache misses. In this paper, we propose and analyze a novel cache organization, called precharging cache, that aims at reducing the number of cache misses resulting from context switches. The key to the proposed scheme is to precharge the cache with the cache contents of next-to-be-scheduled process by making use of the idle bus bandwidth between the cache and main memory near the end of time quantum. In the proposed cache organization, the cache contents of the next-to-be-scheduled process are loaded into the cache before the execution using the block address and the process id information of the previously displaced cache blocks. This precharging strategy reduces the cache misses due to context switches since the working set is already in the cache by the time a process resumes execution. A quantitative performance evaluation based on trace-driven simulation using BACH traces reveals that the precharging cache scheme reduces the total cache misses by 0.68-9.52% and the user-mode cache misses by 2.81-15.3%.

고당 및 올레산으로 유도된 간세포에서의 염증반응에 대한 말차(Camellia sinensis) 추출물의 보호효과

김종민(Jong Min Kim),이욱(Uk Lee),강진용(Jin Yong Kang),박선경(Seon Kyeong Park),신은진(Eun Jin Shin),문종현(Jong Hyun Moon),김민지(Min Ji Kim),이효림(Hyo Lim Lee),김길한(Gil Han Kim),정혜린(Hye Rin Jeong),박효원(Hyo Won Park),김종철(J 한국식품과학회 2021 한국식품과학회지 Vol.53 No.3

본 연구는 가루녹차의 가공품인 말차를 이용하여 항산화 평가와 고당으로 유도된 간세포에서의 간세포 보호효과와 지방간 개선 활성을 평가하기 위해 진행되었다. 말차의 catechin 함량과 총 페놀성 화합물 및 총 플라보노이드 화합물의 함량은 잎 녹차보다 우수한 함량을 나타내었으며, 라디칼 소거활성과 지질과산화물 억제활성 역시 잎 녹차보다 우수한 것을 확인하였다. 또한, 항당뇨 활성을 나타내는 α-glucosidase, α-amylase 및 최종당화산물에 대한 우수한 억제활성을 확인하였다. In vitro 간세포 보호효과를 평가한 결과, 말차는 효과적으로 산화적 스트레스 및 고당으로 인한 활성산소 생성 억제활성과 간세포 생존율 나타내었다. 또한, oleic acid로 유도된 지방 축적에 대한 말차 추출물의 억제활성을 확인하였으며, 지방간으로 인한 염증반응에 대한 조절을 확인하였다. 이러한 연구 결과를 바탕으로 녹차의 가공품 중 하나인 말차는 가공 전 잎 녹차에 비해 우수한 카테킨 함량과 항산화 활성을 지니며, 탄수화물의 섭취를 억제해주는 소화효소의 활성을 억제하여 간세포의 지질축적을 억제하는 데 도움을 줄 수 있을 뿐만 아니라 염증 감소에 도움을 줄 수 있는 소재로서의 가능성을 확인하였다. To evaluate hepatoprotective effects, the antioxidant capacities of matcha green tea extract (Camellia sinenesis) were compared to those of green leaf tea and the anti-inflammatory activities in HepG2 cells were investigated. Evaluation of the total phenolic and total flavonoid content, 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity, and inhibitory effect on lipid peroxidation indicated that the aqueous extract of matcha green tea presented significant catechin content and antioxidant capacity compared to those of green leaf tea. In addition, the extract had considerable inhibitory effects on α-glucosidase, α-amylase, and advanced glycation end-products. The matcha green tea extract significantly increased cell viability and reduced reactive oxygen species in H₂O₂- and high-glucose-treated HepG2 cells. Furthermore, in response to oleic acid-induced HepG2 cell injury, treatment with matcha green tea aqueous extract inhibited lipid accumulation and regulated the expression of inflammatory proteins such as p-JNK, p-Akt, p-GSK-3β, caspase-3, COX-2, iNOS, and TNF-α. Matcha green tea could be used as a functional material to ameliorate hepatic lipid accumulation and inflammation.

전력케이블 건전도 평가를 위한 방법 연구

김종민(Chong-Min Kim),권오민(Oh-Min Kwon),정기석(Ki-Seok Jeong),김영석(Young-Seok Kim) 대한전기학회 2020 대한전기학회 학술대회 논문집 Vol.2020 No.7