제6분과 : 국제경영 3. 엔화강세와 일본기업의 수출가격정책

민선식 한국경영학회 1991 춘계학술연구발표회 발표논문집 Vol.- No.-

토끼의 고전적 순막 조건화 중에 가한 내측 중격의 전기자극이 조건화 및 해마 치상회의 유발전위에 미치는 효과

민선식,이민수,이두현,김현택 한국심리학회 한국심리학회지 생물 및 생리 Vol.10 No.1

해마에서 관찰되는 장기상승작용(long-term potentiation:LTP)현상은 학습과 기억의 유력한 세포적 기전으로 제안되고 있다. 하지만 현재까지 LTP와 학습의 관계를 직접 조사한 연구는 소수에 불과하고 그 결과도 일치되지 않고 있다. 이에 본 연구는 토끼의 순막조건화를 이용하여 LTP현상과 조건화의 관계를 조사하였다. 본 실험은 1) 순막조건화에 의해서 해마 LTP가 유도되는지, 2) 해마에 입력하는 내측중격(medial septum:MS)를 자극하는 것이 조건화와 해마(hippocampus)의 LTP 유도에 어떤 영향을 미치는지를 조사하였다. 이를 위해서 흔적조건화를 사용하였으며 해마의 또 다른 입력구조물인 관통로(perforant path:PP)에 검사자극을 가하여 해마 치상회(dentate gyrus)에서 LTP 발생 여부를 측정하였다. 동물들을 CS-US 배쌍집단, MS자극을 받는 CS-US 배쌍 집단, CS-US 비배쌍 집단 그리고 관통로의 검사자극이 없는 CS-US 배쌍 집단에 무선배정 하였다. 실험결과, 배쌍집단에서는 LTP가 유도되었으나 비배쌍 집단에서는 LTP가 유도되지 않았다. MS를 자극한 집단은 그렇지 않은 집단에 비해 조건화의 촉진이 나타났다. 하지만 관통로에 가한 검사자극에 대한 해마치상회의 반응성에서는 차이를 보이지 않았다. 이러한 결과는 관통로를 통해 입력된 학습관련 정보들이 해마의 LTP를 유도할 가능성을 나타내고 있으며, LTP가 학습의 신경적 기전의 하나임을 시사하고 있다. 한편, 순막조건화 동안 내측중격을 통해 해마로 들어오는 정보는 조건화에 조절적 역할을 할 가능성을 나타내고 있으며, 이 기전은 후내피질(entorhinal cortex)에서 관통로를 통해 해마로 들어오는 학습관련 정보의 처리에 관한 세포적 기전과는 독립적임을 시사한다. Long-term potentiation (LTP) of hippocampal synapses has been suggested to be a cellular mechanism for the learning and memory. However, few studies have reported a relationship between LTP and the behavioral index and the results have often been inconsistent with each other. The present study was conducted to see: 1) if LTP develops in the hippocampal dentate gyrus during classical conditioning of rabbit's nictitating membrane response (NMR) and 2) if stimulation of the medial septum, which is known to be an afferent structure, affects the induction of the LTP and the classical conditioning. Animals were pseudorandomlyassigned to one of four following experimental conditions: 1) CS(conditioned stimulus)-US(unconditioned stimulus), 2) CS-US with the electrical stimulation of medial septum, 3) unpaired presentation of CS and US 4) CS-US without test pulse to the perforant path. The results revealed that the three paired groups showed the robust acquisition compared with the unpaired group. The amplitude of evoked potential at hippocampal dentate gyrus to the test pulse of the perforant path during the acquisition was significantly increased in two paired groups with the test pulse, but not in the unpaired group. The electrical stimulation of the medial septum facilitated the behavioral acquisition without a change in evoked potential of dentate gyrus. The results of this study suggest that learning-related information from the enthorhinal cortex carried via perforant path induces LTP at hippocampus, and information to hippocampus carried via the medial septum modulates acquisition in conditioning of NMR, which can be independent of the induction mechanism of LTP.

CFD를 이용한 자동차 사이드 미러의 공력특성 연구

민선식,한준규,권기현,최은동,김문상,Min, Sun-sik,Han, Jun-Kyu,Kwon, Ki Hyun,Choi, Eun-Dong,Kim, Moon-Sang 항공우주시스템공학회 2008 항공우주시스템공학회지 Vol.2 No.2

Aerodynamic characteristics, such as drag and lift, play an important role in automobile design under certain speed conditions. Such characteristics are essential to design an automobile since they are directly related to automobile's performance such as passenger safety and fuel consumption. There is a huge demand for the automobile to have safe performance at high speed. Reduction in drag is also important and it could lead to the solution of air flow induced noise and dust problems. The objective of this research is to find out the aerodynamic differences between conventional side mirror and a modified one using CFD. Although drag generated around a side mirror is only about 7% of the total drag when a car runs, it is very closely related to driver's field of vision and noise generation. CFD simulation of the flowfield around a car side-view mirror was performed using a commercial code; Gambit and FLUENT.

Effects of NOS Inhibitors on Arthritis and Arthritic Pain in Rats

민선식 대한약리학회 2007 The Korean Journal of Physiology & Pharmacology Vol.11 No.6

Changes of single unit activity of CA1 hippocampus region were investigated in anesthetized Mongolian gerbils for six days following transient ischemia. Ischemia was produced immediately before the implantation of micro-wire recording electrodes. In control animals receiving pseudo-ischemic surgery, neither spontaneous neuronal activities (5.70±0.4 Hz) nor the number of recorded neurons per animal changed significantly for six days. Correlative firings among simultaneously recorded neurons were weak (correlation coefficient >0.6) in the control animals. Animals subjected to ischemia exhibited a significant elevation of neural firing at post-ischemic 12 hr (9.95±0.9 Hz) and day 1 (8.48± 0.8 Hz), but a significant depression of activity at post-ischemic day 6 (1.84±0.3 Hz) when compared to the activities of non-ischemic control animal. Ischemia significantly (correlation coefficient <0.6) increased correlative firings among simultaneously recorded neurons, which were prominent especially during post-ischemic days 1, 2 and 6. Although the numbers of spontaneously active neurons recorded from control group varied within normal range during the experimental period, those from ischemic group changed in post-ischemic time-dependent manner. Temporal changes of the number of cells recorded per animal between control group and ischemic group were also significantly different (p = 0.0084, t = 3.271, df = 10). Cresyl violet staining indicated significant loss of CA1 cells at post-ischemic day 7. Overall, we showed post-ischemic time-dependent, differential changes of three characteristics, including spontaneous activity, network relationship and excitability of CA1 cells, suggesting sustained neural functions. Thus, histological observation of CA1 cell death till post-ischemic day 7 may not represent actual neuronal death.

불란서 대학교육제도

민선식,Min, Seon-Sik 한국과학기술단체총연합회 1975 과학과 기술 Vol.8 No.8

전라북도 성과관리의 현재와 과제

민선식 한국정책분석평가학회 2013 한국정책분석평가학회 학술대회발표논문집 Vol.2013 No.2

백서에서 바질 에센셜 오일의 항통각 효과

민선식 ( Sun Seek Min ),한승호 ( Seung Ho Han ),이재용 ( Jae Yong Yee ),김찬 ( Chan Kim ),설근희 ( Geun Hee Seol ),임재형 ( Jae Hyeung Im ),김형태 ( Hyung Tae Kim ),이규창 ( Kyu Chang Lee ),김혜영 ( Hye Young Kim ),이명종 ( Myeon 대한통증학회 2009 The Korean Journal of Pain Vol.22 No.3

Japanese Export Price Strategy during the Appreciation of the Yen

민선식 ( Sun Shik Min ) 한국국제경영학회 1992 國際經營硏究 Vol.3 No.1

This paper examines how Japanese exporters were able to retain their market shares in Korea when the yen appreciated sharply beginning from 1985. The limited decrease in Japan`s share resulted from (1) an opportunistic share-holding pricing strategy of Japanese exporters: they reduced yen prices even further to retain their shares in cases where they were otherwise likely to lose large shares, and (2) inelastic Korean demand. This study focuses on the pricing behavior of Japanese exporters, using Korean import data and information from field interviews. Some factors enabled Japanese exporters to reduce yen prices. Yen costs of imported inputs for Japan`s exports fell, and Japanese exporters squeezed profit margins that existed before the yen appreciated. Some of them even subsidized price reductions with part of the windfall profits that they realized at home because they did not pass on the decrease in cost of imported inputs to domestic consumers. Subsidized price reductions, accompanied by cost reduction efforts, were a long-term strategy of preempting the entry of competitors since cost reduction required time. If the yen appreciates further, Japanese exporters are likely to substitute imported inputs for Japanese domestic value-added or shift to foreign production while reducing yen prices to defend their markets. This paper uses data from the author`s doctoral dissertation at the Harvard Business School, “The Appreciation of the Yen and Japan`s Exports to Korea.”The author received valuable comments from Louis T. Wells, Jr., Alice H. Amsden, and Benjamin-Gomes Casseres, and financial support from the Harvard Business School`s Division of Research for the dissertation.

내측 전전두피질의 변연하영역손상이나 변연전영역손상이 조건공포의 습득과 소거에 미치는 영향

윤영화,민선식,이민수,김현택 한국심리학회 한국심리학회지 생물 및 생리 Vol.10 No.1

내측 전전두피질의 복측부위(변연하영역)에 가한 손상이나 배측부위(변연전영역)에 가한 손상이 조건공포반응의 습득과 소거에 미치는 영향을 동결반응을 측정하여 조사하였다. 습득기간과 소거기간 동안 동결반응을 측정하였으며, 조건자극(CS)이 제시되기 전 20초 동안과 CS가 제시되는 20초 동안 동결반응을 측정하여 훈련상자인 맥락자극에 대한 조건공포반응과 CS에 대한 조건공포반응을 따로 조사하였다. 변연하영역 손상집단이나 변연전영역 손상집단, 그리고 통제시술집단 모두 조건화 습득기간 중 맥락자극에 대해서 동결반응을 보인 시간에서는 차이가 나타나지 않았다. 그러나 조건화 2일째에 변연하영역 손상집단과 변연전영역 손상집단이 CS에 대한 공포반응을 통제시술집단보다 유의미하게 많이 나타내었다. 2, 3, 4 훈련회기에서 맥락자극이 제시되는 기간과 CS가 제시되는 기간의 각 20초 검사기간 중 18~20초 동안 최대 동결반응치를 보인 회수를 합한 값을 종속변인으로 하여 세 집단을 비교한 결과, 세 집단간에 유의미한 차이가 없었다. 변연하영역 손상집단은 CS에 대한 습득을 촉진시키고 CS에 대한 소거를 지체시켰다. 변연전영역 손상집단은 CS에 대한 습득을 촉진시키고 맥락자극과 CS 모두에 대한 소거를 지체시켰다. 그렇기 때문에 정상적인 상태에서는 변연하영역과 변연전영역은 조건공포에 억제작용을 한다고 생각된다. This study investigated the role of infralimbic(IL) and prelimbic(PL) areas of medial prefrontal cortex on the acquisition and extinction of conditioned fear response in rats using Pavlovian conditioning paradigm. Conditioned fear behavior(freezing response) was measured during both the acquisition and extinction phases of the task. Conditioned fear was measured both to the conditioned stimulus(CS) and to the contextual stimuli during both phases. IL lesion group, PL lesion group, and sham operated group showed similar conditioned fear to the contextual stimuli during acquisition. IL lesion and PL lesion enhanced conditioned fear to the CS in 2nd conditioning day. IL lesion prolonged conditioned fear to the CS(but not to the context) during extinction. PL lesion prolonged conditioned fear both to the CS and to the context during extinction. These results suggest that IL and PL are involved in emotion, especially fear, and that they are important in inhibition of conditioned fear.

마우스 대동맥에서 버가못(Citrus bergamia Risso) 에센셜 오일의 혈관이완 효과 in vitro

강푸름,민선식,설근희 한국간호과학회 2012 한국간호과학회 학술대회 Vol.2012 No.10