• 전자공학회논문지SC
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• 제46권4호
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• pp.70-76
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• 2009

본 연구에서는 자동차 사고나 뇌졸중 둥에 의해 경추 이하의 마비나 손, 발 등의 움직임이 자유롭지 못한 사람들의 컴퓨터 사용을 돕고자 손이나 발을 이용하지 않고 머리의 움직임과 눈의 깜박임만으로 컴퓨터 마우스 제어가 가능한 장치를 제안하였다. 마우스의 위치는 각속도 센서를 이용하여 머리의 움직임으로 추정하고, 눈 깜빡임에 의한 클릭과 더블 클릭은 광센서의 시야를 방해하지 않는 위치에 장착하여 커 클위치와 이벤트를 검출하였다. 제안한 마우스의 공간 이동 능력과 이벤트 검출을 비교한 실험에서는 좌우, 상하 이동은 기존 마우스와 비교하여 속도 면에서는 큰 차이는 없었으나, 정확도가 조금 떨어지는 이유로 인하여 정확한 위치로 이동시키는데 소요시간이 3$\sim$4배 정도 더 필요하였다. 데드 존을 갖는 비선형 상대 좌표계 방식을 이용하여 주기적으로 적분 에러를 제거해야 하는 문제를 해결하였고, 이동 거리와 속도를 함께 고려하여 직관적인 마우스 포인터 제어가 가능하도록 하였다. 주변광의 영향을 최소화하도록 광원 제어 회로를 설계하여 외부 광원의 변화에도 마우스 이벤트 검출이 영향을 받지 않았다.

• 한국염색가공학회지
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• 제24권4호
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• pp.288-295
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• 2012

Although some degree of mechanical properties of suede fabrics mainly related to non-woven suede fabric has some researched, the thin suede fabric has rarely been researched. In this study, polyester(DTY 50/72) was used for warp, and after producing latent yarn and sea-island yarn for weft, two yarns were compounded to produce sea-island DTY yarn. By using the two produced yarns for warp and weft, we produced thin suede fabric with stretch function. For weft 2ply, weft density 85, 90, 100(picks/in) were applied to weave fabric, and for weft 1ply, weft density 125, 135, 140(picks/in) were applied to produce weft face 5-end satin weave. The mechanical properties of the produced fabric were researched. The result are as followed. The weight loss ratio of the suede fabric produced for this experiment reached 15% on the conditions of temperature $90^{\circ}C$ and 20 minutes, so that island parts were completely separated. The strength of weft 1ply applied suede fabric was about 7.5kg and that of 2ply suede fabric and about 3.5kg. But the strain of two samples ranged from about 40 to 43%. Although Hari was high when weft was denser. The values of Koshi and Kisimi were low. And shear stiffness was high when sea-island DTY yarn was used. The WC value was higher in the case of 2ply than in that of 1ply sea-island DTY yarn for weft, so that we may conclude that Fukurami was more affected in the 2ply case.

• 한국산학기술학회논문지
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• 제22권4호
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• pp.473-482
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• 2021

자동화된 운항 시스템 도입으로 항공안전은 크게 개선되었지만, 운항을 직접 담당하는 항공기 조종사에게는 새로운 도전이 생겼다. 항공운항 관점에서의 조종사의 스트레스를 Startle과 Surprise구분할 수 있다. Startle을 총소리 같이 갑작스럽거나 위협적인 자극에 대한 짧고 강한 생리적인 반응이며, Surprise는 자신의 예상을 빗나가는 예기치 못한 사건에 대한 인지-감정적 반응이다. Martin 등이 실시한 Startle 효과 실험(2012년)에서 조종사는 Startle 상태에서 반응 지연과 심박 수 증가 등 생리적인 반응을 확인하였고, Rahim의 Startle/Surprise 실험(2020년)에서 사전 계획된 비상조치훈련은 조종사의 호흡수와 맥박수의 변화가 없으나, 비계획된 상황과 항공기가 복잡할수록 호흡 수와 심박 수가 증가되었다는 사실을 확인하였다. 이 실험 결과를 바탕으로 국내 조종사 훈련에서도 기술적 능력을 전달에만 집중하는 것이 아닌 비기술적 능력에 대한 고려가 필요하며, 법령에 의한 기계획된 단순 반복적인 훈련 항목보다는 항공사의 상황을 고려한 비정형화된 다양한 비상조치 훈련의 도입이 필요하다고 하겠다.

• 한국의류학회지
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• 제43권3호
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• pp.405-415
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• 2019

This study examined the physiological and psychological effects of wearing a winter cap at rest in a cold environment. Seven older males participated in two separate trials: wearing a winter cap (CAP) and non-wearing a winter cap (CON). The experiment was conducted for 60 min in a climatic chamber (air temperature $7.8{\pm}0.3^{\circ}C$ with $43{\pm}2%RH$) with sedentary posture. Microclimate temperature at the vertex of the head was $6.88^{\circ}C$ higher in CAP compared to CON (p<.01). Microclimate humidity at the vertex was lower in CAP than in CON only during the last 5 min (p<.01). Skin temperature at the forehead in CAP was higher than in CON (p<.01). During the last 5 min, rectal temperature was higher in CAP than that in CON (p<.05). Unlike CAP, the heart rate in CON during the last 5 min decreased significantly compared to the initial 5 min (p<.05). Subjects also felt less cold on the head/face in CAP than that in CON (p<.01). The results indicate that wearing a cap for elderly males positively affected body temperature regulation and cardiovascular response in cold environments. The importance of wearing warm hats for elderly males in winter should be emphasized.

• 한국환경생태학회지
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• 제35권4호
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• pp.424-434
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• 2021

고령화 시대에 퇴직을 맞이하는 사람들은 회복탄력성과 심리적 우울의 변화를 경험하게 된다. 한국 사회의 경제사회분야에서 중심적 역할을 주도해 온 베이비부머 세대의 퇴직이 시작되면서 이들의 퇴직 이후의 삶에도 관심이 높아지고 있다. 본 연구에서는 생태숲이 가지고 있는 산림치유인자들을 활용한 산림치유 프로그램을 통해 베이비부머 은퇴자들의 회복탄력성, 우울에 미치는 영향을 알아보고자 하였다. 실험은 베이비부머 세대 58명을 대상으로 3그룹으로 구분하여 그룹 간 차이를 검정하였다. 그 결과 산림치유 프로그램에 참여한 그룹(FHPG)은 자율적인 숲 활동 그룹(FHNG)과 일상생활 그룹(DLG)에 비하여 회복탄력성이 매우 유의미하게 증가되었고, 우울감도 통계적으로 유의하게 감소되었다. 따라서 은퇴자들의 자율적인 숲 활동 보다도 산림치유 프로그램에 참여하는 것이 매우 효과적이라고 할 수 있다. 본 연구 결과가 향후 은퇴자들의 회복탄력성과 우울 연구에 기초자료로 활용되기를 기대한다.

• 대한치과보철학회지
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• 제36권6호
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• pp.858-866
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• 1998

Soldering is the usual method used to correct an unstable fixed partial denture framework at patient's try-in; However, presoldering base metal alloys is technique-sensitve and results are unstable because it is difficult to maintain uniform heat distribution and to prevent oxidation of an alloy. A cast-joining technique has been developed by Weiss and Munyon for repair, correction and addition to base metal framework. This joining technique eliminates the problem with presoldering of non-precious frameworks. The object of this study was to 1) compare the relative flexure strength and the joining effectiveness of Ni-Cr-Be cast in two pieces and 'pre-soldered' versus in two pieces and 'cast-joined'. 2) determine the effect of increasing the number of retentive grooves on the face of the cast and 3) determine the effect of the relative matched position of groove patterns on flexure strength. The joining effectiveness can be expressed by the ratio of the mean flexure stress of soldered or cast-joined specimens to that of one-piece cast. Resin rods 3mm in diameter were used as pattern of specimens for one-piece casted, presoldered, and cast-joined groups. Cast-joined specimens had two different patterns of retentive grooves on the joined faces. Type A had cross-shaped grooves 1mm in depth. 0.6mm in width. Type B was the same except for the addition of one more retentive groove. In the experiment connecting cast-joined specimens, half of specimens with type A pattern had their patterns on the faces of paired casts matched with each other as mirror image. With the rest pairs, it was proceeded that one of paired casts turned 45 degrees so that the patterns crossed. Half of specimens with type B pattern also had the patterns matched as mirror image; However, here, one of paired casts turned 90 degrees with the other pairs. Retentive groove in this study lacked the intentional undercuts, in contrast with the suggestion of Weiss and Munyon. The specimens were subjected to four-point flexural loading in an Instron testing machine. The midspan flexural stress was calculated at the point of initial plastic strain as determined from a strip-chart recorder or at the point of failure if this occured at a lower stress level. Within the scope of this study, the following results were obtained. 1. The presoldered group showed flexural strength at least 2 times higher than the cast-joined groups. Its joining effectiveness was 82%. 2. In cast-joined groups, the flexural strength of joints with type B patterns exhibited 1.5 times that of joints with type A patterns. Joining effectivenesses were 38% for type B patterns, 25-26% for type A patterns. 3. The relative matched position of groove patterns did not have any significant effect on flexural strength of the cast-joined specimens with either type A patterns or type B patterns(p>.05).

• Journal of Pharmaceutical Investigation
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• 제25권3호spc1호
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• pp.7-20
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• 1995

Taurine, a ${\beta}-amino$ acid, plays an important role as a neuromodulator and is necessary for the normal development of the brain. Since de novo synthesis of taurine in the brain is minimal and in vivo studies suggest that taurine dose not cross the blood-brain barrier, we examined whether the choroid plexus, the blood-cerebrospinal fluid (CSF) barrier, plays a role in taurine transport in the central nervous system. The uptake of $[^3H]-taurine$ into ATP depleted choroid plexus from rabbit was substantially greater in the presence of an inwardly directed $Na^+$ gradient taurine accumulation was negligible. A transient in side-negative potential gradient enhanced the $Na^+-driven$ uptake of taurine into the tissue slices, suggesting that the transport process is electrogenic, $Na^+-driven$ taurine uptake was saturable with an estimated $V_{max}$ of $111\;{\pm}\;20.2\;nmole/g/15\;min$ and a $K_M\;of\;99.8{\pm}29.9\;{\mu}M$. The estimated coupling ratio of $Na^+$ and taurine was $1.80\;{\pm}\;0.122.$ $Na^+-dependent$ taurine uptake was significantly inhibited by ${\beta}-amino$ acids, but not by ${\alpha}-amino$ acids, indicating that the transporter is selective for ${\beta}-amino$ acids. Since it is known that the physiological concentration of taurine in the CSF is lower than that in the plasma, the active transport system we characterized may face the brush border (i.e., CSF facing) side of the choroid plexus and actively transport taurine out of the CSF. Therefore, we examined in vivo elimination of taurine from the CSF in the rat to determine whether elimination kinetics of taurine from the CSF is consistent with the in vitro study. Using a stereotaxic device, cannulaes were placed into the lateral ventricle and the cisterna magna of the rat. Radio-labelled taurine and inulin (a marker of CSF flow) were injected into the lateral ventricle, and the concentrations of the labelled compounds in the CSF were monitored for upto 3 hrs in the cisterna magna. The apparent clearance of taurine from CSF was greater than the estimated CSF flow (p<0.005) indicating that there is a clearance process in addition to the CSF flow. Taurine distribution into the choroid plexus was at least 10 fold higher than that found in other brain areas (e. g., cerebellum, olfactory bulb and cortex). When unlabelled taurine was co-administered with radio-labelled taurine, the apparent clearance of taurine was reduced (p<0.0l), suggesting a saturable disposition of taurine from CSF. Distribution of taurine into the choroid plexus, cerebellum, olfactory bulb and cortex was similarly diminished, indicating that the saturable uptake of taurine into these tissues is responsible for the non-linear disposition. A pharmacokinetic model involving first order elimination and saturable distribution described these data adequately. The Michaelis-Menten rate constant estimated from in vivo elimination study is similar to that obtained in the in vitro uptake experiment. Collectively, our results demonstrate that taurine is transported in the choroid plexus via a $Na^+-dependent,saturable$ and apparently ${\beta}-amino$ acid selective mechanism. This process may be functionally relevant to taurine homeostasis in the brain.

• 한국콘텐츠학회논문지
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• 제20권2호
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• pp.581-593
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• 2020

이 연구의 목적은 가상현실 시뮬레이션에서 아바타에 대한 사용자의 주의집중이 어떻게 일어나는가를 분석하기 위한 것이다. 주의집중 정도를 알기 위해서 시선추적 기법을 적용했으며, 이를 통하여 사용자가 아바타의 어느 부분에 초점을 두고 있는지 검증하고자 하였다. 이 연구에서는 수업시뮬레이션에서 아바타에 대한 사용자의 시선응시 시간과 가상실재감을 분석했다. 실험참가자는 대학생 45명(여학생=21명, 남학생=24명)이었다. 이 연구에서는 가상현실 기반의 수업시뮬레이션이 사용되었으며, 교권침해에 대한 시나리오들이 적용되었다. 종속변수는 아바타에 대한 사용자의 시선응시시간이며 3개의 관심영역(AOI)에 대한 차이분석을 실시했다. 또한 실험조건에 대한 사용자의 가상실재감(공간실재감, 몰두감, 사실성)을 측정했다. 실험참가자는 두 가지 시나리오를 모두 경험했으며, 반복측정에 의한 다변량분산분석을 실시했다. 연구결과에 의하면 시나리오와 AOI에 의한 유의미한 상호작용이 있었고, 시나리오와 AOI에 따른 주효과도 유의미한 차이가 보였다. 시나리오의 유형과 상관없이 사용자는 언제나 아바타의 얼굴표정에 상당히 많은 시선응시를 하고 있는 것으로 나타났다.