• 약학회지
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• 제37권4호
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• pp.383-388
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• 1993

Pharmacokinetics of aucubin, an irdoid glucoside, was compared in rats of experimental hepatic failure(EHF). EHF was induced by CCI$_{4}$ or D-galactosamine pretreatment. This work was designed to find out any differences in the pharmacokinetics of aucubin that may explain the different protective effect of aucubin on CCI$_{4}$- and galactosamine-induced EHF : aucubin reportedly protected CCI$_{4}$-inducing hepatotoxicity effectively, but did not for galactosamine-hepatotoxicity. EHF was induced by intraperitoneal injection Of CCI$_{4}$(0.9ml/kg) or galactosamine(250 mg/kg) to Wistar rats 24 hr before the pharmacokinetic study. The rats were fasted during the 24 hr. Aucubin was iv injected at a dose of 15 mg/kg and the plasma aucubin was assayed by HPLC. There were no significant differences in the pathophysiologies(body weight, liver weight, GTP, hematocrit, blood cell distrbution and plasma protein binding of aucubin) between the two EHF models except GOP which was significantly (p<0.05) higher in CCI$_{4}$-than in galactosamine-EHF. On the other hand, pharmacokinetics of aucubin such as total cleatance(CL$_{t}$), distribution volume at steady-state(Vd$_{ss}$), and mean residence time(MRT) differed significantly(p<0.05) between the models : for example, CL$_{t}$ was increased two fold by CCI$_{4}$, but not by galaclosamine ; Vd$_{ss}$, in galactosamine-EHF was higher than that in CCI$_{4}$-EHF ; MRT was decreased by CCI$_{4}$, but increased conversely by galactosamine. The increase of CL$_{t}$(and decrease of MRT) in rats of CCI$_{4}$-EHF was contrary to the general expectation for the hepatic failure : most of the hepatic failures have been known to decrease CL$_{t}$ of the administered drugs. Whether the difference in the pharmacokinetics is responsible for the different protective effect of aucubin against the two EHF models is of interest. However, much more studies on biliary excretion, urinary excretion, and hepatic uptake in cellular level should be preceded before any conclusions are made on the role of different pharmacokinetics on the different pharmacology of aucubin.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1998년도 추계학술대회
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• pp.281-282
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• 1998

Recently, there has been growing interest in the assessment of physiological parameters on brain perfusion that provide more information than pure morphologic diagnosis. Quantification of parameters that characterize cerebral micro-circulation with magnetic resonance imaging is of great relevance for clinical application. We determine the local tissue concentration by exponential relationship between the relative signal reduction S(t)/$S_0$ and local tissue concentration of contrast material $C_m(t)$ in dynamic susceptibility contrast enhanced MR imaging. And then we made relative regional blood volume map by calculating the area under the measured concentration-time curves $C_m(t)$ during first pass of paramagnetic contrast material as a preliminary step for perfusion map. These images make it possible to compare the rCBV in different brain regions in one individual at a time. We have it in contemplation to obtain arterial and brain signal time curves simultaneously to make absolute rCBV and perfusion (rCBF) map. These maps may provide the method of comparative investigations of different patients having strong variation in AIF.

• 헤리티지:역사와 과학
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• 제43권2호
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• pp.82-119
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• 2010

"공정주법칙례(工程做法則例)"는 건물의 영조표준을 통일하고 공정관리제도를 강화하기 위한 목적으로 청나라 옹정(雍正) 12년(1734년) 공부에서 간행한 책이다. 영조표준을 만들기 위해 두구(斗口)를 기준으로 한 부재 하나하나의 치수가 기록되어 있으며, 공정관리를 위한 여러 비용의 기록 또한 존재 한다. 현재 이러한 기록들은 당시의 건축기술 및 건축환경을 짐작해 볼 수 있는 중요한 자료로 인식되고 있다. 하지만 우리나라 건축사학계는 북송 시기에 간행된 "영조법식(營造法式)"의 연구에 집중된 경향이 있어 "공정주법칙례"는 그 중요성은 인정 받고 있으나 아직 번역 작업조차 이뤄지지 않은 상태이다. 따라서 여기서는 "공정주법칙례"의 기본적인 내용들을 서두에 밝히고, 권1의 원문을 번역하여 소개함으로써 이후 연구의 기초자료를 제공하는데 그 목적을 두었다.

• 대한의용생체공학회:의공학회지
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• 제16권2호
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• pp.223-230
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• 1995

Rb-82 dynamic PET과 이중적분법에 의한 국소 심근 혈류측정 연구를 시행하고자 실험 개를 이용한 심근 경색 모델과 허혈성 심근질환에서 좌심실 입력함수에 의한 정상 및 관류결손 심근에서의 혈류를 측정하였다. 이중적분법이 선형회귀모델에 의한 혈류측정방법에 비하여 안정도가 높고 심근내혈류가 선형적인 가정을 배제할 수 있어 사용 가능한 방법이 될 수 있음을 확인하였다.

• Journal of Korean Neurosurgical Society
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• 제29권12호
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• pp.1634-1641
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• 2000

Objective : The cerebrospinal fluid(CSF) pulsates within the craniospinal axis in response to rhythmic cerebral blood volume variation during the cardiac cycle. The aim of this study is to characterize the normal and abnormal CSF flow and its waveforms in the cervical spinal subarachnoid space. Methods : The magnetic resonance(MR) images were obtained with 1.5 T(GE Signa, GE Medical Systems, Milwaukee, USA) unit using the 2 dimensional cine PC(phase contrast) sequence with cardiac gating and gradient recalled echo imaging. This pulse sequence yielded 16 quantitative flow-encoded images per cardiac cycle. Sagittal and axial images of the cervical spinal CSF space were obtained, and target sites were analyzed for characteristic CSF flow (TR=50ms, TE=12.5-15ms). The region of interest(ROI) was 1mm 3 in volume. Twenty six persons were included in this study : 10 healthy volunteers and 16 patients with cervical myelopathy. The post-operative cine MR study were also done in five patients. Results : The normal CSF pulsation dynamics in the cervical spine showed discrete systolic and diastolic components. The CSF flow revealed a sine wave pattern, in which the systolic phase was shorter than the diastolic phase(ratio=2 : 3). The patient group revealed decreased amplitudes of the CSF flow and irregularly distored flow waves. The systolic phase was elongated in the ROI above the stenotic level, whereas the diastolic phase was lengthened below the level. In the postoperative images, the abnormal pattern and amplitude were found to be corrected. Conclusion : From these results, the authors believe that the CSF flow study provides valuable informations regarding the extent of cervical stenosis and may be useful for the surgical planning and post-operative evaluation.

• 한국도로학회논문집
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• 제20권4호
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• pp.47-58
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• 2018

PURPOSES : Seoul introduced public bicycles to reduce environmental pollution and create a healthy society. Because the use of bicycles is highly weather dependent, and bicycles are rented by the people, member characteristics and seasonal influences should be considered. This study analyzed bicycle traffic characteristics considering seasonal and member characteristics and highlighted some implications. METHODS : The Yeouido and Sangam districts, which have multiple business districts, were taken as the areas of interest. In order to reflect seasonal and membership characteristics, the traffic volume, time of use, and characteristics of each zone were categorized by season (spring, summer, autumn, winter) and membership type (season, daily, group). In addition, we analyzed the pattern of traffic volume and usage time according to the traffic purpose after separating rental locations into residential, business, subway, and park, reflecting the land characteristics. RESULTS : The results revealed that seasonal characteristics were high for bicycle traffic, time of use, and occupancy rate for park locations in spring and autumn. In terms of membership characteristics, group and daily users appeared as major visitors for park locations, and the trends of commuter pass users showed that bicycle use meets the purpose of introducing public bicycles. CONCLUSIONS : Traffic characteristics differed according to seasonal and membership characteristics. It is necessary to involve and extend the users of the commuter pass. Situations in which commuter pass users cannot function as a group or in which daily users monopolize bicycles (especially near parks, near subway stations, etc.) must be avoided.

• 대한교통학회지
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• 제33권6호
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• pp.520-530
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• 2015

본 논문은 장기적 및 단기적 관점에서 도시내 도로의 최적 혼잡통행료를 추정하는 방법론을 구축하고, 이를 서울시의 주요 도로에 적용하였다. 장기적 관점의 최적 혼잡통행료는 도로 건설 유지비용과 통행자비용을 합한 총비용을 극소화하는 최적 교통량-용량 비율을 구한 다음 추정된다. 반면 단기적 관점의 최적 혼잡통행료는 통행시간-교통량 함수와 개별수단선택모형을 이용해 공급-수요 균형점을 구한 다음 추정된다. 도시고속도로인 서부간선도로에 대한 장기적 관점의 분석 결과 최적 교통량-용량비율과 승용차-km당 최적 혼잡통행료는 1.35와 503원인 반면, 도시간선도로인 미아로에 대한 단기적 관점의 분석 결과는 1.31과 420원인 것으로 나타났다. 이러한 분석 결과는 어느 정도 할인율과 시간 가치에 영향을 받으나, 혼잡통행료를 부과하면 사회후생이 증가하는 것은 변함이 없는 것으로 나타났다.

• 지능정보연구
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• 제28권4호
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• pp.81-94
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• 2022

최근 고액의 실물자산이나 채권을 분할하여 여러 투자자가 공동으로 투자하는 이른바 조각투자가 인기를 얻고 있다. 2016년 설립된 뮤직카우는 음원 유통에 따른 저작권료 참여 청구권을 조각투자할 수 있는 서비스를 세계 최초로 시작하였다. 본 연구에서는 딥러닝 알고리즘 중 하나인 LSTM 모델을 사용하여 뮤직카우에서 거래되는 저작권료 참여 청구권의 가격을 예측하는 연구를 진행하였다. 청구권의 이전 가격과 거래량, 저작권료와 같은 청구권과 관련된 변수 외에도, 음악저작권료 참여 청구권 시장 상황을 나타내는 종합 지표와 경제 상황을 반영하는 환율, 국고채 금리, 한국종합주가지수도 변수로 사용하였다. 연구 결과 상대적으로 거래량이 낮은 조각투자의 사례에서도 LSTM 모델이 거래가격을 잘 예측하는 것을 확인할 수 있었다.

• 한국자동차공학회논문집
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• 제17권2호
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• pp.132-140
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• 2009

Recently, the interest in the development of high efficiency Diesel engine technology using alternative fuel has been on the rise and related studies are being performed. Therefore, the DME(Dimethyl Ether), an oxygen containing fuel as an alternative fuel for light oil that can be used for diesel engines since it generates very little smoke. But it is unavoidable that the modification of a fuel supply system in an engine to application of the DME fuel because of DME fuel properties. So, in this study, a DME high pressure pump for a common-rail fuel supply system has been composed and the test results of the pump have been presented. As the results of the tests, it is confirmed that DME pump inlet pressure, pump speed and common-rail pressure effects on the volumetric efficiencies of the pump. Finally, it is defined that the optimum plunger volume of a DME pump has to be extended to the minimum 150% compared to a Diesel pump plunger volume considering DME fuel properties and volumetric efficiencies characteristics at same specifications of the high pressure pump.

• 전자공학회논문지
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• 제50권8호
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• pp.225-231
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• 2013

의료영상분할은 다양한 의료영상처리를 수행하기에 앞서 먼저 수행되어야 하는 영상처리 기술이다. 그래서 빠르고 정확한 의료영상분할이 요구되고 있으며 다양한 의료영상분할 방법이 연구되고 있다. 의료영상에는 특성이 유사한 다양한 장기가 존재하기 때문에 분할영역의 정확한 판단이 필요하다. 그러나 의료영상은 장기의 일부가 작게 촬영되는 경우가 발생된다. 이 경우에는 분할영역을 판단하기 위한 정보가 부족하게 되며 그 결과 분할과정에서 분할영역이 제거된다. 본 논문에서는 볼륨 데이터와 선형 방정식을 이용하여 작은 영역에서의 분할결과를 개선하였다. 제안한 방법의 성능을 확인하기 위하여 흉부 CT 영상의 폐 분할을 수행하였다. 실험 결과, 의료영상의 분할 정확도는 0.978에서 0.981로 표준편차는 0.281에서 0.187로 개선되는 것을 확인하였다.