• Journal of Korean Neurosurgical Society
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• 제55권4호
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• pp.185-189
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• 2014

Objective : General anesthesia is often preferred for endovascular coiling of intracranial aneurysm at most centers. But in the authors' hospital, it is performed under monitored anesthesia care (MAC) using dexmedetomidine. To determine the feasibility and safety of this approach, the authors reviewed our initial experience. Methods : Retrospective data was analyzed from July 2012 to November 2012. We performed coil embolization in 28 cases using this method. Among them, for statistical significance, we analyzed 12 cases in which the procedure time exceeded an hour. Vital signs were analyzed every 10 minutes. Depth of sedation was measured according to the Ramsay sedation scale and frequency of the repeated roadmap image(s) caused by movement of the patient's head during the procedure. Results : All procedures were completed without occurrence of procedure related complications. Under MAC using dexmedetomidine, vital signs of the patients were stable, no statistical significance regarding hemodynamic and respiratory parameters was observed between time points (p>0.05). Adequate sedation was achieved. Mean Ramsay sedation scale was $3.67{\pm}1.61$ (2 to 6). Repeated roadmap image(s) due to patient's factor occurred in only one case. The mean dosage of drug for adequate sedation for the procedure was $0.65{\pm}0.12mcg/kg/hr$ without loading doses. Conclusion : To the best of my knowledge, this is the first report published in English using the method of monitored anesthesia with dexmedetomidine for intracranial aneurysm coiling. Monitored anesthesia care using dexmedetomidine without loading dose for embolization of intracranial aneurysms appeared to be a safe and effective alternative to general anesthesia.

• 한국지반공학회논문집
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• 제18권2호
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• pp.39-49
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• 2002

본 연구에서는 지반-말뚝 상호작용을 고려한 동해석을 위한 해석기법의 제안과 이의 검증을 위한 진동실험을 실시하였다. 일정한 가속도에서 단독말뚝과 중심간격 2.5d(d=직경)인 2$\times$2 군말뚝의 휨모멘트 값을 측정한 결과 주파수에 관계없이 지표면으로부터 깊이 4d 미만에서 단독말뚝과 군말뚝의 휨모멘트값이 최대가 되었으며 그 값은 단독, 군말뚝 모두 일치하였으나 지표면으로부터 깊이 4d이하에서는 단독말뚝은 군말쪽에 비해 휨모멘트 값이 커지는 경향을 보였다. 진동대 실험에서 측정한 입력가속도를 수치해석에서 지진가속도로 하여 해석한 결과 단독말뚝과 군말뚝 모두 지표면으로부터 4d 미만의 상부부분에서는 실험값과 비슷한 결과를 얻었으나 군말뚝의 경우 지표면으로부터 4d 이상의 부분에서는 실험 값과는 상이한 결과를 얻었다.

• 대한토목학회논문집
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• 제32권2C호
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• pp.79-84
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• 2012

말뚝에 작용하는 다양한 하중 및 현장시험결과를 통해 얻은 특정한 p-y 곡선을 적용하기에 적합한 횡방향말뚝 해석기법을 구축하였다. 구축된 해석기법을 다양한 문제에 적용하여 그 신뢰성을 검증하고 해석에서 고려한 인자들이 해석결과에 미치는 영향을 살펴보았다. 해석기법 적용시 절점간 거리가 말뚝지름의 1/2 정도일 때 해의 정확도가 높아짐을 알 수 있었다. 해석기법 적용을 통해 과다한 변위에 대해 안전한 말뚝길이 결정문제와 자립길이를 갖는 말뚝에 대하여 축력에 의한 좌굴을 검토해 보았다. 또한 옹벽 하부구조물로서의 말뚝의 말뚝머리 구속조건에 따른 해석결과를 비교하여 보았다. 개발된 해석기법은 상용 프로그램을 적용하는데 비해 해석자의 의도에 보다 적합한 유연한 해석수단이 될 것으로 생각된다.

• 한국지반공학회논문집
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• 제19권2호
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• pp.49-55
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• 2003

본 연구에서는 연직말뚝과 경사말뚝에 대하여 수행한 압력토조 모형실험을 통하여 경사말뚝의 연직하중과 침하량 관계로부터 경사각도에 따른 압축지지력의 증가양상을 분석하였다. 실트질 모래로 형성된 상대밀도 50%의 포화지반에 경사각 0$^\circ$, 5$^\circ$, $10^\circ$, 15$^\circ$, 20$^\circ$의 모형 개단강관말뚝을 항타 관입하였으며, 압력토조내의 구속압력을 35, 70, 그리고 120 kPa로 변화시키면서 재하실험을 수행하였다. 연직 압축지지력은 경사각도가 커짐에 따라 증가하였으며 분석방법에 따라 증가율에는 다소의 차이가 수반되었으나 경사각 5$^\circ$, $10^\circ$, 15$^\circ$인 경우 지지력 증가율은 각각 111, 121, 127 ~ 140 % 정도를 나타내었다. 경사각이 20$^\circ$ 이상인 경우에는 말뚝 두부의 전도로 인하여 모형실험의 수행이 곤란하였다.

• 해양환경안전학회지
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• 제25권1호
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• pp.130-137
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• 2019

원심 해수냉각 펌프를 분석하기 위하여 다른 운전 유량에 대한 캐비테이션 거동을 조사하였다. 3D 2상 해석은 ANSYS-CFX 상용코드로 수행되었다. 해석에는 $k-{\varepsilon}$ 난류와 Rayleigh-Plesset cavitation 모델이 사용되었다. 수치 예측에 기초하여 세 가지 토출 유량값에 대하여 헤드 드롭 특성곡선이 작성되었다. 더 높은 유량에서 임펠러는 버블 캐비테이션에 보다 취약하다. 0.7Q, Q 및 1.3Q(Q: 설계 유량)에서 작동하는 펌프의 3 % 헤드 드롭 위치는 각각 NPSHa 1.21 m, 1.83 m 및 3.45 m에 해당한다. 증기 기포의 볼륨이 예측되고 캐비테이션의 위치는 임펠러 내에서 발생하는 캐비티를 시각화하여 예상하였다. 또한, 압력계수와 날개 부하 분포가 구체적으로 제시되어 캐비테이션이 펌프 운전에 미치는 해로운 영향을 나타냈다. 또한, 압력계수 분포와 날개부하 차트가 구체적으로 제시되어, 펌프 운전에 캐비테이션이 미치는 해로운 영향을 나타냈다.

• 대한토목학회논문집
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• 제28권1C호
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• pp.31-40
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• 2008

본 연구에서는 지진하중을 받는 Single Column/Shaft의 내진해석으로 의사정적해석법을 적용하였으며 해석상에서 지반의 비선형 거동특성을 나타내는 다양한 수평방향 하중전이특성(p-y 곡선, Bi-linear 곡선)를 이용하여 지반-말뚝의 상호작용을 고려하였다. 비선형 지반모델을 적용한 해석은 지반-말뚝 시스템의 지진거동을 간편히 예측할 수 있었으며 동일한 해석조건에서 응답변위법에 의한 Single Column/Shaft의 수평거동이 진도법에 근거하여 산정한 해석결과보다 크게 예측되었다. 두부경계조건과 상대강성이 Single Column/Shaft의 단면력에 미치는 영향을 분석하기 위해 다양한 지반모델에 대한 변수연구를 수행한 결과, 두부경계가 고정이고 말뚝강성이 감소할수록 수평변위가 작은 것으로 나타났으며, JRA의 Bi-linear 지반모델을 적용한 해석은 Single Column/Shaft의 수평거동을 비교적 정확히 예측하였다.

• The Journal of Korean Physical Therapy
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• 제22권5호
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• pp.77-82
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• 2010

Purpose: The purpose of this study was to compare the pathway of COP and plantar foot pressure and to determine the correlation between plantar regions during the ascending and descending of a ramp. Methods: Fifteen healthy adults who had no musculoskeletal problems participated in our study. They were asked to walk on a level surface and on an ascending and descending ramp in their bare feet. Pathway of COP and plantar foot pressures were recorded using the Matscan system (Tekscan, Boston, USA). For pressure measurements, the plantar foot surface was divided into seven regions: two toe regions, three forefoot regions, a midfoot region, and a heel region. To determine whether there was a statistically significant difference between pathway of COP and plantar foot pressures during walking, we used repeated measuremes ANOVA. Results: In comparison to results for a level walking, pathway of COP while ascending a ramp had a tendency to be shifted medially in the forefoot and became longer till the big toe. Pathway of COP while descending a ramp also was shifted medially, but ended in the forefoot. Plantar foot pressure of the second and third metatarsal head and the fourth and fifth metatarsal heads was significantly decreased while descending the ramp. Conclusion: These results indicated that plantar foot pressure is changed while ascending and descending a ramp and demonstrated that ramp walking can affect the structure and function of the foot. Therefore, gait environment is associated with significant changes in foot characteristics, which contribute to altered plantar loading patterns during gait.

• 지역사회간호학회지
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• 제13권4호
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• pp.608-617
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• 2002

The purpose of this study was to analyze phenomena and characteristics of family nursing in Korea based on the study by Yun et al. (1999) by ICNP. The subjects of this study were 115 reports on family nursing care in Korea National Open University. The results of this study were as follows; 1. In the phenomenon of family nursing, 'Inappropriate family coping' comprised of 17.0% and 'Inadequate care for a sick member' comprised of 16.8%. 2. It was found that 'A few close neighbors was 62.5%, 'Lack of communication between married couple' was 60.0%, 'Neglet of general child rearing' was 40.9%, 'Closed communication pattern of the head of a family' was 36.0%, and 'Inadequate distribution of each family member's role' was 27.2%. 3. 'Lack of family interaction in community' and 'Social isolation' were combined with 'Lack of family interaction in community', and 'Disturbance in family communication' and 'Lack of family intimacy' were combined with 'Disturbance in family communication'. 4. 'Dual-loading with office work and housework', 'Overload of caring one's elders because of the status as a dual-income family' and 'Lack of family support system' were added into 'Inappropriate family coping'.

• International Journal of Automotive Technology
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• 제7권5호
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• pp.555-564
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• 2006

The aim of this paper is to contribute to the efficient design of traffic light poles involved in vehicle frontal collisions by developing a computer-based, finite-element model capable of capturing the impact characteristics. This is achieved by using the available non-linear dynamic analysis software "LS-DYNA3D", which can accurately predict the dynamic response of both the vehicle and the traffic light pole. The fiber reinforced polymer(FRP) as a new pole's material is proposed in this paper to increase energy absorption capabilities in the case of a traffic pole involved in a vehicle head-on collision. Numerical analyses are conducted to evaluate the effects of key parameters on the response of the pole embedded in soil when impacted by vehicles, including: soil type(clay and sand) and pole material type(FRP and steel). It is demonstrated from the numerical analysis that the FRP pole-soil system has favorable advantages over steel poles, where the FRP pole absorbed vehicle impact energy in a smoother behavior, which leads to smoother acceleration pulse and less deformation of the vehicle than those encountered with steel poles. Also, it was observed that clayey soil brings a slightly more resistance than sandy soil which helps reducing pole movement at ground level. Finally, FRP pole system provides more energy absorbing leading to protection during minor impacts and under service loading, and remain flexible enough to avoid influencing vehicle occupants, thus reducing fatalities and injuries resulting from the crash.

• Steel and Composite Structures
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• 제27권5호
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• pp.647-659
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• 2018

Through extensive research, there exist a new type of connection between railway bridge girders and steel-concrete composite panels. In addition to conventional shear connectors, newly developed blind bolts have been recently adopted for retrofitting. However, the body of knowledge on their influence and application to railway structures has not been thoroughly investigated. This study has thus placed a particular emphasis on the application of blind bolts on the Sydney Harbour Bridge as a feasible alternative constituent of railway track upgrading. Finite element modeling has been used to simulate the behaviours of the precast steel-concrete panels with common types of bolt connection using commercially available package, ABAQUS. The steel-concrete composite track slabs have been designed in accordance with Australian Standards AS5100. These precast steel-concrete panels are then numerically retrofitted by three types of most practical bold connections: head studded shear connector, Ajax blind bolt and Lindapter hollow bolt. The influences of bolt connections on load and stress transfers and structural behaviour of the composite track slabs are highlighted in this paper. The numerical results exhibit that all three bolts can distribute stresses effectively and can be installed on the bridge girder. However, it is also found that Lindapter hollow bolts are superior in minimising structural responses of the composite track slabs to train loading.