• 터널과지하공간
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• 제13권1호
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• pp.44-51
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• 2003

응력 재분포에 의해 발생하는 수리전도도의 변화를 평가하기 위하여 변형률 의존 수리전도도 변화방정식을 사용하였다. 주요 입력 변수는 탄성계수 감소비와 응력 재분포에 의해 발생한 변형률이다. 무결암에서부터 완전히 파쇄된 암반조건을 나타내기 위하여 탄성계수 감소비 대신에 탄성계수 감소비와 RMR간의 상관관계를 이용하였다. 전단 변형에 따른 팽창이 수리전도도의 증가에 영향을 미치지만 그 영향 정도는RMR에 따라 달라졌으며, 인장변형률이 절리에 작용하는 경우 암반의 RMR이 감소함에 따라 수리전도도는 증가하는 것으로 나타났다. 암반에 작용하는 응력 상태에 따라 수리전도도의 변화도 다른 것으로 나타났는데, 수평응력 대 수직응력의 비가 다른 이방성 응력 상태가 수리전도도의 변화에 가장 큰 영향을 미치는 것으로 나타났다.

• 한국강구조학회 논문집
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• 제15권1호
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• pp.25-31
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• 2003

본 연구는 데크플레이트의 모멘트 강도에 관한 실험적, 이론적 연구를 수행하였다. 실물크기의 14개 모멘트 실험을 행하였으며, 가력부의 국부좌굴을 방지하기 위해 1/4지점 집중하중을 가력하였다. 기준식들 간의 차이점을 이론적으로 비교분석하였다. 또한 미국 AISI, 유럽 EC3, 한국 기준과 실험값을 비교 평가하였다. 파괴모드는 보 중앙부의 국부좌굴 및 중간가력부의 국부좌굴에 의하여 형성되어 최대내력에 도달하였다. 인장측이 먼저 항복하는 경우 소성능력이 인장측에서 발휘되어 내력이 증대하였다. 설험결과는 인장측 부분 소성화를 고려한 EC 기준과 가장 잘 일치하였다. EC3 부록Z에 의한 통계학적 평가로부터 EC3 기준식이 목표로 하는 $^{\circ}{_M}=1.1$ 이내로 그 적용성이 만족되었다. AISI와 KS 기준에서도 소성화 개념을 추가한다면, 이론해석이 보다 더 개선될 것이다.

• Journal of Chest Surgery
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• 제20권4호
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• pp.643-654
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• 1987

The effect of prostacyclin[PGI, ] on myocardial preservation during global ischemia was studied in the isolating working rabbit heart model. Forty hearts underwent a 15 minute period of retrograde nonworking perfusion with Krebs-Henseleit buffer solution [37*C] and were switched over to the working mode for 15 minutes. After baseline measurement of heart rate, peak aortic pressure, aortic flow, and coronary flow, all hearts were subjected to 60 minutes of ischemic arrest at 10*C induced with St. Thomas Hospital cardioplegic solution: Group I had single dose cardioplegia, Croup II double dose, Croup III oxygenated double dose, and Group IV single dose with PCI, infusion [10ng/min./gm heart weight]. Hearts were then revived with 15 minute period of nonworking reperfusion at normothermia, followed by 30 minutes of working perfusion. Repeat measurements of cardiac function were obtained and expressed as a percent of the preischemic baseline values. Oxygen content of arterial perfusate and coronary effluent was measured by designed time interval. Leakage of creatine kinase was determined during post-ischemic reperfusion period. Finally wet hearts were weighed and placed in 120*C oven for 36 hours for measurement of dry weight. In the PGI, treated group [IV], heart rate increased consistently throughout the period of reperfusion from 100*5.0% [p<0.001] to 107*6.2% [p<0.001]. The percent recovery of aortic flow showed 95*5.7% [p<0.001] at the first 3 minute and full recovery through the subsequent time. Coronary flow was augmented significantly in the 3 minute [96*6.2%, p<0.001] and then sustained above baseline values. Among the Croup I, II, and III, all hemodynamic values were significantly below preischemic levels. PGI2 relatively increased oxygen delivery [1.22*0.19ml/min, p<0.001] and myocardial oxygen consumption [0.90*0.13ml/min, p<0.001] during reperfusion period. Leakage of creatine kinase in the PGI2 group was 9.3*1.58IU/15min [p<0.001]. This was significantly lower than Group I [33.0*2.68 IU/15min]. The water content of PCI2 treated hearts [81*0.9%, p<0.001] was also lower than the other groups.

• 한국자동차공학회논문집
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• 제21권3호
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• pp.82-87
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• 2013

In this work, the 1L grade integrated metal DOC/DPF filter that can install in engine manifold position was developed to investigate the effect of platinum-coating amount of filter on the improvement of filter activation temperature and reduction of particulate matter (PM). This filter was installed in 2.9L CI engine which meets the EURO-4 emission regulation. Tests for PM reduction efficiency of filter were conducted under ND-13 mode with full-load test condition. It was revealed that the time to reach the activation temperature of metal filter ($280^{\circ}C$) was shorter as the amount of platinum-coating increased. This short activation time can be helpful for the reduction of CO and HC emissions during cold start condition. At the same time, PM reduced as the coating amount increased. The reduction percentage of $DOC_{40}$, $DOC_{20}$, and $DOC_0$ were 96.7% (2.34 mg/kW'h), 95.1% (3.47 mg/kW'h), and 94.5% (3.69 mg/kW'h) compared to previous result (71.4 mg/kW'h), respectively.

• 대한의용생체공학회:의공학회지
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• 제28권1호
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• pp.36-45
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• 2007

Today Human Personal Trainers are becoming very famous in this health conscious world. They teach user to achieve fitness goals in managed way. Due to their high fee and tight schedule they are unavailable to mass number of people. Another solution to this problem is to develop digital personal trainer portable instrument that may replace human personal trainers. We developed a portable digital exercise trainer device - BIOFIT that manages, monitors and records the user's physical status and workout during exercise session. It guides the user to exercise efficiently for specific fitness goal. It keeps the full exercise program i.e. exercises start date and time, duration, mode, control parameter, intensity in its memory which helps the user in managing his exercise. Exercise program can be downloaded from the internet. During exercise it continuously monitors the user's physiological parameters: heart rate, number of steps walked, and energy consumed. If these parameters do not range within prescribed target zone, the BIOFIT will alarm the user as a feedback to control exercise. The BIOFIT displays these parameters on graphic LCD. During exercise it continuously records the heart rate and number of steps walked every 10 seconds along with exercise date and time. This stored information can be used as treatment for the user by an exercise expert. Real-time ECG monitoring can be viewed wirelessly (RF Communication) on a remote PC.

• Coupled systems mechanics
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• 제2권4호
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• pp.329-348
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• 2013

This study aims at observing the coupling behaviours between suspended ceilings and partition walls in terms of their global seismic performance using full-scale shake table tests. The suspended ceilings with planar dimensions of $6.0m{\times}3.6m$ were tested with two types of panels: acoustic lay-in and metal clip-on panels. They were further categorized as seismic-braced, seismic-unbraced, and non-seismic installations. Also, two configurations of 2.7 m high partition wall specimens, with C-shape and I-shape in the plane layouts, were tested. In total, seven ceiling-partition-coupling (CPC) specimens were tested utilizing a unidirectional seismic simulator. The test results indicate that the damage patterns of the tested CPC systems included failure of the ceiling grids, shearing-off of the wall top railing, and, most destructively, numerous partial detachments and falling of the ceiling panels. The loss of panels was mostly concentrated near the center of the tested partition wall. The testing results also confirmed that the failure mode of the non-seismic CPC systems was brittle: The whole system would collapse suddenly all at once when the magnitude of the inputs hit the capacity threshold, rather than displaying progressive damage. Overall, the seismic capacity of the unbraced and braced CPC systems could be up to 1.23 g and 2.67 g, respectively; these accelerations were both achieved at the base of the partition wall. Nonetheless, for practical applications, it is noteworthy that the three-dimensional nature of seismic excitations and the size effect of the ceiling area are parameters that exacerbate the CPC's seismic response so that their actual capacity may be dramatically decreased, leading to important losses even in moderate seismic events.

• 전자공학회논문지SC
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• 제37권2호
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• pp.29-36
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• 2000

본 논문에서는 트랜지스터 동작영역에 독립적인 일정 트랜스컨덕턴스 rail-to-tail 입력회로 및 AB-급 출력회로를 갖는 2단 연산증폭기를 제시한다. rail-to-rail 입력회로는 추가 NMOS 및 PMOS 차동 입력단 구조를 사용하여, 전체 동상 입력 전압에서 항상 일정한 트랜스컨덕턴스를 갖도록 하였다. 이러한 입력단 회로는 기존 MOS의 정확한 전류-전압 관계식을 사용하지 않고, 트랜지스터의 동작영역에서, 즉 강 반전 및 약 반전, 독립적인 새로운 광역 선형 전류관계를 제안한다. 본 논문에서 제안한 입력단 회로를 SPICE를 사용하여 모의실험 결과, 전체 동상 입력 전압에 대해서 4.3%의 변화율이 나타남을 검증하였다. AB-급 출력단 회로는 공급 전압원에 독립적인 일정한 동작 전류값을 갖고, 출력 전압은 Vss+0.1에서 Vdd-0.15까지 구동하는 전압 특성을 나타내었다. 또한 출력단은 AB-급 궤환 제어 방식을 사용하여 저전압에서 동작 할 수 있다. 전체 연산 증폭기의 단일-이득 주파수 및 DC 전압이득 변화율은 각각 4.2% 및 12%로 나타냈다.

• 복식문화연구
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• 제6권1호
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• pp.136-148
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• 1998

This is a study on the change of the Medievalmen's underclothes. Underclothing includes all such articles, worn by either sex, as were completely or mainly concealed from the spectator by the external costume. Throughout the Middle Ages, the underclothing of both sexes possessed characteristic inherited from earlier times. Its function was purely utilitarian. It was not used to express class distinction and only very indirectly to enhance sex attraction. The idea of underclothes was associated with the idea of the body's sinfulness. Underclothes could also symbolize the discipline of humility. To appear clad only in underclothes was a voluntary form of selfabasement often practised by pilgrims. The notion that underclothes might express the spirit of the changing times, in sympathy with the outer clothing, did not enter the medieval mind. The length of the shirt was less than that of the modern garment, especially after the middle of the fourteenth century. The sleeves were somewhat full, without cuffs, and cut straight. During the second half of the twelfth century, when braies become definitely an undergarment. In the fourteenth century braies became shorter and shorter and the shirt could no longer be tucked in but hung outside over the thighs. After 1340 the costume on the surface somewhat resembling modern 'tights', began to reveal display the shape of the male leg as a form of sex attraction. By the close of the Middle Ages, braies had become less like loincloths, and more like modern bathing trunks. The peasant and laborer did not attempt to keep pace with the changes of fashion but, continued, as a rule, to wear the long braies of their forefathers. The higher ranks how this garment reflected the changes of the mode of outer costumes.

• 한국통신학회논문지
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• 제27권8C호
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• pp.803-811
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• 2002

트리 구조의 광 가입자망인 ATM-PON에서의 DBA 기능은 다양한 트래픽을 경제적이고 효율적으로 전송하기위해 연구되어 왔다. 본 논문에서는 ONU의 버퍼상태정보 전달방법 및 공정한 대역할당방법 등을 포함한 효율적인 DBA 알고리즘을 제안한다. DBA 알고리즘은 사용자측에서 발생한 트래픽의 형태를 그대로 유지하면서 상향데이터 흐름을 효과적으로 다중화하고, 트래픽 종류별 QoS를 만족시키도록 설계되어야 한다. 이를 위하여, 제안한 알고리즘에서는 각 ONU의 버퍼상태정보 외에 ONU 마다 다섯 종류의 대역정보를 사용한다. ONU의 버퍼상태정보를 OLT로 전달하기 위한 방법으로 미니슬롯을 사용한다. 각 미니슬롯은 해당 ONU의 버퍼에 있는 비실시간 셀이 얼마나 되는지를 나타낸다. OLT는 각 ONU에 정의된 다섯 종류의 대역정보 및 미니슬롯을 통해 전달받은 각 ONU의 버퍼에 있는 비실시간 셀 수를 이용하여 각 ONU에 공평하게 대역을 할당한다. 제안한 DBA 알고리즘에 대한 성능평가를 위하여 평균전송지연시간 및 지연변이 등의 관점에서 시뮬레이션을 실시하여 그 결과를 기술한다.

• 한국초전도저온공학회지:초전도와저온공학
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• 제20권2호
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• pp.15-22
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• 2018

The present article briefly overviews the plan for a new project on joint technology for HTS wires/cables and describes the development plan for the world's highest field NMR magnet, which is a major development item in the project. For full-fledged social implementation of superconducting devices, high temperature superconducting (HTS) wire is a key technology since they can be cooled by liquid nitrogen and they can generate a super-high magnetic field of >>24 T at liquid helium temperatures. However, one of the major drawbacks of the HTS wires is their availability only in short lengths of a single piece of wire. This necessitates a number of joints being installed in superconducting devices, resulting in a difficult manufacturing process and a large joint resistance. In Japan, a large-scale project has commenced, including two technical demonstration items: (i) Development of superconducting joints between HTS wires, which are used in the world's highest field 1.3 GHz (30.5 T) NMR magnet in persistent current mode; the joints performance is evaluated based on NMR spectra for proteins. (ii) Development of ultra-low resistive joints between DC superconducting feeder cables for railway systems. The project starts a new initiative of next generation super-high field NMR development as well as that of realization of better superconducting power cables.