관류 강조 자기공명 영상을 이용한 소아 모야모야 환아의 뇌 혈역학 분석

장원석,김태곤,이승구,최중언,김동석,Chang, Won-Seok,Kim, Tae-Gon,Lee, Seung-Koo,Choi, Jung-Uhn,Kim, Dong-Seok 대한신경외과학회 2005 Journal of Korean neurosurgical society Vol.37 No.3

Objective: Classically, single photon emission tomography is known to be the reference standard for evaluating the hemodynamic status of patients with moyamoya disease. Recently, T2-weighted perfusion magnetic resonance(MR) imaging has been found to be effective in estimating cerebral hemodynamics in moyamoya disease. We aim to assess the utility of perfusion-weighted MR imaging for evaluating hemodynamic status of moyamoya disease. Methods: The subjects were fourteen moyamoya patients(mean age: 7.21 yrs) who were admitted at our hospital between Sep. 2001 to Sep 2003. Four normal children were used for control group. Perfusion MR imaging was performed before any treatment by using a T2-weighted contrast material-enhanced technique. Relative cerebral blood volume(rCBV) and time to peak enhancement(TTP) maps were calculated. Relative ratios of rCBV and TTP in the anterior cerebral artery(ACA), middle cerebral artery(MCA) and basal ganglia were measured and compared with those of the posterior cerebral artery(PCA) in each cerebral hemispheres. Using this data, we analysed the hemodynamic aspect of pediatric moyamoya disease patients in regarding to the age, Suzuki stage, signal change in FLAIR MR imaging, and hemispheres inducing symptoms. Results: The mean rCBV ratio of ACA, MCA did not differ between normal children and moyamoya patients. However the significant TTP delay was observed at ACA, MCA territories (mean = 2.3071 sec, 1.2089 see, respectively, p < 0.0001). As the Suzuki stage of patients is advanced, rCBV ratio is decreased and TTP differences increased. Conclusion: Perfusion MR can be applied for evaluating preoperative cerebral hemodynamic status of moyamoya patients. Furthermore, perfusion MR imaging can be used for determine which hemisphere should be treated, first.

퍼지기반 Segment-Boost 방법을 통한 효과적인 얼굴인식

장원석,노창현,이종식,Chang, Won-Suk,Noh, Chang-Hyeon,Lee, Jong-Sik 한국시뮬레이션학회 2009 한국시뮬레이션학회 논문지 Vol.18 No.1

This paper suggests fuzzy-based Segment-Boost method and an effective method for face recognition using the fuzzy-based Segment-Boost. Fuzzy-based Segment-Boost eliminates the limitations of Segment-Boost, and it guarantees improved learning performance and the stability of the performance. By using the fuzzy theory, fuzzy-based Segment-Boost optimizes the selection number of sub-vectors, and leads the optimized learning performance. The fuzzy controller designed in this paper measures learning performance of the fuzzy-based Segment-Boost, and it controls the selection number of sub-vectors by inferring the optimized selection number. The simulation results show that the fuzzy controller inferred the selection number which is very approximate to the true optimized value. As a result, fuzzy-based Segment-Boost showed higher face recognition rate than compared boosting methods and it preserves the velocity of feature selection as fast as that of Segment-Boost. From the experimental results, it was proved that fuzzy-based Segment-Boost has improved and stable performances of learning, feature selection and face recognition.

임계치 이상의 전류자극에 대한 생체의 반응 연구

장원석,최규식,Chang, Won-Seok,Che, Gyu-Shik 한국정보통신학회 2010 한국정보통신학회논문지 Vol.14 No.12

임계치 이하의 자극이 주어지면 흥분막은 어떤 특이한 반응을 나타내지 않으나 어느 정도 이상이 되면 아주 다른 양상을 띄게 된다. 흥분막에는 이러한 특성이 있다는 것이 진작부터 알려져 있었고, 일부 연구자들이 이러한 현상을 전기적인 회로를 이용하여 정량적으로 해석하려 노력하였으나 그것은 임계치 이하의 경우에 대한 것에 불과하다. 특히 임계치 이상의 자극에 대한 반응을 정량적으로 연구한 경우는 극히 드물다. 그런데 전기회로와 생체는 비슷한 점도 있지만 다른 면도 많아서 그대로 이를 적용하기에는 무리가 있다. 이러한 이유로 인하여 본 논문에서는 생체막이 임계치 이상의 자극을 받았을 때에 어떠한 현상을 나타내는가를 전기적인 관점에서 정량적으로 연구하였다 When the inferiorthreshold potential is applied on the membrane, the resting status membrane does not display any specific reaction, in the meanwhile if it receives somewhat higher voltages then it shows entirely different configuration. The fact that there is this kind of characteristics on the exciting membrane has been known for a long time, and some researchers have tried to analyze this situation using the electrical circuits but only limitted to inferiorthreshold potential case. The quantitative studies of especially for transthreshold stimulus is extremely rare up to now. The direct application of electrical circuit to biostatus is somewhat uneasonable because there may be much differences between them. We studied the electrical reaction quantitatively of biomembrane when it receives the transthreshold stimulus in point of electricity in this paper.

단일협동조합 제정의 필요성과 찬반논리

장원석,임진창,김명규 ( Won Suk Chang,Chin Chang Lim,Myung Kyu Kim ) 한국농업경제학회 1992 農業經濟硏究 Vol.33 No.1

LNG 발전배가스 농축 CO₂를 이용한 액화 실증기술의 개발

최창식(Chansgik Choi),박수남(Su-nam Park),이혜성(Hye-sung Lee),박동규(Dong Kyoo Park),장원석(Won- seok Chang),남궁형규(Hyeong-gyu Namgung) 한국환경에너지공학회 2023 한국열환경공학회 학술대회지 Vol.2023 No.2

Liquified carbon dioxide (LCO₂) is a promising alternative to fossil fuels that can be used to reduce greenhouse gas emissions. There is growing research into the use of liquefied CO₂ (LCO₂) to reduce CO₂ emissions, which can be transported deep underground for carbon capture and storage (CCS) and LCO₂ for enhanced oil recovery (EOR). It can be used to extract additional oil by injecting it into oil fields, and can also be used as a raw material and refrigerant for the production of various fuels. This study attempted to conduct an empirical study on the production of LCO₂ with a purity of 90% or higher targeting concentrated CO₂ from LNG flue gas. This study was designed to secure empirical process development technology applicable to existing LNG power generation infrastructure and reduce greenhouse gas emissions in the future and reduce cliinate change. It is expected that it will make a significant contribution to mitigating the impact.

카본나노튜브 스트레인 센서 제작 기술

장원석(Won-Seok Chang),송선아(Sun-Ah Song),김재현(Jae-Hyun Kim),한창수(Chang-Soo Han) 대한기계학회 2009 大韓機械學會論文集B Vol.33 No.10

In this study, the strain sensing characteristics of single-wall carbon nanotubes(SWCNTs) networks were investigated to develop a film sensor for strain sensing. The SWCNTs film are formed on flexible substrates of poly(ethylene terephthalate) (PET) using spray process. In this manner we could control the transparency and obtain excellent uniformity of the networked SWCNT film. The carbon nanotube film is isotropic due to randomly oriented bundles of SWCNTs. Using experimental results it is shown that there is a nearly linear change in resistance across the film when it is subjected to tensile stress. The results presented in this study indicate the potential of such films for high sensitive transparent strain sensors on macro scale.

카본나노튜브 스트레인 센서 제작 기술

장원석(Won-Seok Chang),송선아(Sun-Ah Song),김재현(Jae-Hyun Kim),한창수(Chang-Soo Han) 대한기계학회 2009 대한기계학회 춘추학술대회 Vol.2009 No.5

In this study, the strain sensing characteristics of SWCNTs networks were investigated to develop a film sensor for strain sensing. The SWCNTs film are formed on flexible substrates of poly (ethylene terephthalate) (PET) using spray process. In this manner we could control the transparency and obtain excellent uniformity of the networked SWCNT film. The carbon nanotube film is isotropic due to randomly oriented bundles of SWCNTs. Using experimental results it is shown that there is a nearly linear change in resistance across the film when it is subjected to tensile stress. The results presented in this study indicate the potential of such films for high sensitive transparent strain sensors on macro scale.

나노소재 투명 전도성 박막의 레이저 패터닝 기술

장원석(W.S. Chang) 한국생산제조학회 2013 한국생산제조시스템학회 학술발표대회 논문집 Vol.2013 No.10

인지적 대응에서 느끼는 상응으로 -과정철학의 번역론-

장원석 ( Won Suk Chang ) 한국화이트헤드학회 2015 화이트헤드 연구 Vol.31 No.-

이 논문은 화이트헤드의 유기체 철학을 포함한 과정철학의 전통의 관점에서 번역이라는 문화적 행위를 어떻게 이해할 수 있는가를 논하려는 시도이다. 화이트헤드 자신을 포함한 많은 해석자들은 과정철학을 객관주의적 전통과 주관주의적 전통을 통합한다고 주장한다. 그렇다면 이 관점에서 번역행위는 어떻게 이해될 수 있는가? 화이트헤드는 우리가 추상화된 것을 실재로 이해하는 오류를 저지르고 있으며 관계적, 구체적 경험을 이해하기 위해 사변철학이 필요하다는 점을 논구한다. 이와 같이 나는 텍스트의 이해와 번역을 위해 콘텍스트의 구축이 전제되어야 하며 이는 형이상학이라는 발견의 방법과 다르지 않다고 주장하였다. 이 과정에서 중국 전통 문헌을 이해하는데 전통과 콘텍스트 구축의 유용성에 대한 논쟁을 소개하였다. 또 이 논문을 통해 번역행위를 통해 우리가 전달하고자 하는 것은 텍스트의 인지적 구조라기보다는 저자의 의도, 느낌, 수신자의 반응이라는 것이라고 하였다. 그러면서 성공적인 번역은 원 텍스트가 일으키는 느낌과 번역 텍스트가 일으키는 느낌의 상응이라는 것을 화이트헤드의 명제, 상징적 준거, 현시적 직접성, 인과적 효능 그리고 느낌으로의 유혹 등의 개념을 사용하여 논하였다. 그리고 한국유학의 번역의 사례를 통해 이 이론을 음미하였다. 마지막 부분에서 나는 과정 철학의 관점에서 번역이라는 행위는 행동발화적 행위이며 인간의 감성적 행동적 인지적인 미감적 관점에서 이해되어야 한다고 주장하였다. 번역은 인간 세대 간의 소통적 과정에서 참여와 도야를 유도하는 교육적 행위로 이해되어야 한다고 결론지었다. This article is an attempt to define translation in terms of process philosophical tradition including works of A.N. Whitehead. If many interpreters place process tradition between the objectivist and the subjectivist philosophical traditions, how can we construe translation activities from the standpoint of process view? As Whitehead postulates necessity of his speculative philosophy against abstraction, many translators stress necessity of constitute interpretive context or generalization of the tradition. According to them Otherwise we cannot properly place the notion in the tradition and fail to translate them in the proper context. I also argue constitutive, heuristic method is needed for the understanding and translating texts. I also discuss recent debates over usefulness of tradition or context in understanding and translating Chinese texts. I also argue in translation what we convey is feelings, intention, respond of the imagined author-receptor rather cognitive appearance. For successful translation, there should be felt equivalences between source texts and target texts rather than correspondence of the characters. I tried to explain this by using ideas of proposition, symbolic reference, presentational immediacy, causal efficacy, and lure for feeling in the Whitehead’s organic philosophy. At the end of article, I try to conclude that according to process view, translation as aesthetic activities and felt equivalence can be understood as the lure for engagement in the transitive and communicative process of human generations for richer and continuous civilization.

자동차 네비게이션 시스템을 위한 햅틱 시트의 평가에 관한 연구

장원석(Wonsuk Chang),김석환(Seok Hwan Kim),편종권(Jong Kweon Pyun),지용구(Yong Gu Ji) 대한인간공학회 2010 大韓人間工學會誌 Vol.29 No.4

This study has confirmed that subjective positive and negative aspects a driver feels by applying haptic seat on a vehicle to substantiate vehicle navigation system. Our experiment with total twenty subjects provides that the reaction time (RT) is superior in haptic interface than visual or auditory interface but subjective satisfaction, which subjects feel, and workload is less low in a simulator environment. Although, the difference of individuals and unfamiliarity is relatively high inasmuch as the experiment of absolutely new technology, but overall satisfaction of haptic seat is high. The result of study provides some consideration and direction to need in implementation of a haptic seat and it also confirms their possibility meaningfully. We expect the interaction between a driver and a vehicle and safety improvement potentially through applied haptic seat on actual vehicles.