• Explosives and Blasting
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• v.31 no.2
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• pp.40-49
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• 2013

To predict ground conditions ahead of the tunnel face, seismic refraction survey has been widely used. But due to the development in seismic equipment and techniques, tomography using borehole and others are actively applied in recent years. This study has a purpose to prevent stability problems during excavation and construction of tunnels by predicting unfavorable ground conditions such as fault, fractured zone and rock quality variation zone ahead of the tunnel face using TSP survey equipment. In this study, the validity of predicting ground conditions ahead of tunnel face by TSP survey has been evaluated through the case study in the road construction site.

• Journal of Korean Tunnelling and Underground Space Association
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• v.17 no.3
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• pp.383-392
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• 2015

In subsea tunnelling, prediction of the fractured zone (or water bearing zone) ahead of tunnel face saturated by seawater with high water pressure has been a key factor for safe construction. This study verified the feasibility of utilizing induced polarization (IP) survey at tunnel face for predicting the ground condition ahead of the subsea tunnel face. A pore model was proposed to compute chargeability in granular material, and the relationship correlating chargeability with the variables affecting the chargeability was derived from the model. Parametric study has been performed on the variables to figure out the most influential factors affecting the chargeability. The results of the parametric study show that the size of narrow pores ($r_1$) and the salinity of pore water are the most influential factors on chargeability. Laboratory tests were conducted on various types of ground condition by changing the salinity of pore water, the thickness of the fracture zone and the existence of gouge (weathered granite) within the joints of the fractured zone to figure out the effect of the ground characteristics on the IP phenomenon. Test results show that the chargeability of the fractured zone saturated by seawater increases if the joints in the fractured zone are filled with gouge since the infilled gouge will decrease the size of narrow pores ($r_1$).

• Journal of the Korea Society for Simulation
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• v.27 no.4
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• pp.19-26
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• 2018

The aerial launching UAV(Unmanned Aerial Vehicle) mainly uses a set of folding tandem wings to maximize flight performance and minimize the space required for mounting in a mothership. This folding tandem wing has a unique aerodynamic problem that is different from the general type of fixed wing aircraft, such as the rear wing interference problem caused by the wing of the front wing wake and vortex, and the imbalance of the pivot moment applied to the front and rear wings when the wing is deployed. In this paper, we have modeled and simulated various cases through computational fluid dynamics based on the finite volume method and analyzed various aerodynamic phenomena of the tandem wing type aircraft. We find that the front wing shall be installed higher than the rear for minimizing the wake influence and the rear wing can be deployed faster than the front because of the pivot moment due to aerodynamic forces. Also, considering the pivot moment due to aerodynamic force, the rear wing can be deployed much faster than the front wing. Therefore, it is necessary to consider it when developing the wing deploy mechanism.

• The korean journal of orthodontics
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• v.20 no.3 s.32
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• pp.463-498
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• 1990

전기적 자극에 의한 골성장기전의 개념을 이용하여 임상적 효율성을 증진시키기 위한 연구는 현재 교정학을 비롯한 치과영역에서 활발히 진행되고 있는 분야 중의 하나이다. 전기적 자극의 여러 형태 중의 하나인 전자기장과 하악의 기능적 전방 이동을 유도하는 악기능교정장치가 백서의 하악과두 성장에 미치는 영향을 구명하기 위하여 본 연구를 시행하였다. 생후 4주된 Sprague Dawley계 백서 48마리를 대조군 12마리, 실험군 36마리로 나누고, 실험군은 다시 전자기장을 가한 군, 하악골 전방이동 장치를 장착시킨 군, 전자기장과 하악골 전방이동 장치를 병용시킨 군으로 분류하여 각각 12마리씩 실험동물을 배정하였다. 각 군의 실험동물은 15 HZ의 특수 전자기장이나 하악전방이동 자치가 하루10시간씩 작용되도록 특별히 제작한 실험장치 속에 넣어 1주간, 4주간씩 사육하여 희생시킨 후 하악골을 분리하고 연조직을 박리한 후 $10\%$ formalin에 보관하였다. 하악골 길이를 측정하기 위해 0.05mm까지 계측 가능한 캘리퍼를 이용하여 하악과두의 후연에서 이공까지의 거리를 계측하였고, 하악과두를 절제하여 0.5M EDTA에 탈회시켜 파라핀 포매를 하였다. 표본의 절단방향은 시상평면에 평행하게 하여 $6{\mu}m$두께로 연속절단 하였으며, 그 중 중심의 3절편을 취하여 통법에 의한 H-E 중염색을 시행하였다. 하악골 계측과 H-E 중염색 표본을 통한 조직학적 관찰을 통해 다음과 같은 결론을 얻었다. 1. 4주군에서 전자기장만에 노출된 실험군은 대조군에 비해 하악골 길이가 유익성 있게 증가되었다. 2. 전자기장과 하악골 전방이동 장치를 병용한 실험군은 하악골 전방이동장치만을 사용한 실험군에 비하여 하악골 길이가 증가되었다. 3. 전자기장에 노출된 실험군은 전구 연골아세포(prechondroblast)의 증식, 비대연골 세포층의 세포간질 및 연골내 골화층의 석회화가 모두 증가되었다. 4. 본 실험에 사용한 15 HZ전자기장의 주요작용부위는 백서의 하악과두 성장지역 중 연골내 골화의 석회화 지역이며, 또한 이는 하악골 전방이동 장치와 병용시 하악과두 성장을 촉진시킬 수 있음이 관찰되었다.

• Journal of The Korean Dental Society of Anesthesiology
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• v.10 no.2
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• pp.178-182
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• 2010

배경: 임상적으로 굴곡성 기관지 내시경을 이용 삽관 시행시 후두경으로 성문부위가 잘 드러나지 않는 환자의 경우 삽관 시행이 어려운 경우를 경험한다. 하지만 이에 대한 연구는 거의 없는 실정이다. 본 연구에서는 어려운 기도환자에서 굴곡성 기관지경 시행시 후두시야를 확보시 차이가 있는지 확인하고자 하였다. 방법: 전신마취 유도 후 Cormack - Lehane classification을 이용하여 기관 삽관의 어려움을 먼저 평가하였다. 기관지 내시경을 이용하여 내시경하 후두시야의 정도를 평가하였다. 후두경으로 기도 확보가 용이한 그룹(Cormack - Lehane grades 1, 2)과 어려운 그룹(Cormack - Lehane grades 3, 4) 간의 내시경하 후두 시야의 정도가 차이가 나는 지를 확인하였다. 결과: 후두경으로 기도확보가 용이하지 않을 경우에 기관지 내시경으로 후두 시야를 용이하게 (fiberoptic laryngeal view 1, 2) 확보하기가 어려웠다. 반면 하악을 전방으로 견인시 후두시야의 정도가 통계적으로 유의하게 개선되었다. 결론: 전방하악견인법 (jaw-thrust maneuver)은 기도확보가 어려운 환자에서 기관지 내시경을 이용한 기관내 삽관 시행시 시야를 개선시켜서 삽관을 용이하게 할 수 있을 것으로 생각된다.

• Journal of Korean Society of Transportation
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• v.30 no.4
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• pp.43-59
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• 2012

Assuming a completed Smart Highway road & communication environment that allows real-time information collection and transmission of road traffic condition ahead, the purpose of this study is to develop a plan for inducing a network-level safe driving pattern by providing road traffic condition and safety information to multiple drivers through a road information provision device. In this study, the device with a function that displays different colors according to the hazard level to the existing delineator has been named 'Smart Delineator'. Smart Delineator is a device that provides not only alignment information but also safety information for drivers to receive real-time warning information and intuitively recognize road traffic condition ahead so that drivers can respond. To examine the effects of safety driving inducement level on drivers, a simulation test was conducted using driving simulator as well as a satisfaction survey. The result showed that the Smart Delineator was able to identify the location of occurrence and affecting driving according pattern, either adhering to recommended speed or reducing speed according to the pre-defined hazard level.

• Journal of Dental Rehabilitation and Applied Science
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• v.26 no.4
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• pp.463-476
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• 2010

Inadequate or unstable posterior support cause extrusion of antagonistic teeth and overloading of remaining teeth. Extrusion of antagonistic teeth result in collapsed occlusal plane and decreased prosthetic space. Also, overloading of remaining teeth increase occlusal wear or anterior extrusion of anterior teeth, which is resulting in loss of anterior guidance, disharmony of occlusion and decreased prosthetic space. In this case, careful evaluation of OVD(occlusal vertical dimension) is the general first trial to regain appropriate function and esthetics. Simultaneously, adequate anterior guidance and harmonious occlusal plane should be established in the repeatable reference position of the mandible. We report this case because severely worn dentition achieved functional and esthetic results from full mouth rehabilitation with increased vertical dimension and use of centric relation.

• Tunnel and Underground Space
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• v.13 no.6
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• pp.476-485
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• 2003

The purpose of this study is to present an analysis method for the prediction of the change of ground conditions. To this end, three-dimensional convergence displacements is analyzed in several ways to estimate the trend of displacement change. Three-dimensional arching effect is occurred around the unsupported excavation surface including tunnel face when a tunnel is excavated in a stable rock mass. If the ground condition ahead of tunnel face changes or a weak fracture zone exists a specific trend of displacement change is known to be occurred from the results of the existing researches. The existence of a discontinuity, whose change in front of the tunnel face, can be predicted from the ratio of L/C (longitudinal displacement at crown divided by settlement at crown) etc. Therefore, the change of ground condition and the existence of a fracture zone ahead of tunnel face can be predicted by monitoring three-dimensional absolute displacements during excavation, and applying the methodology presented in this study.

• Journal of Oral Medicine and Pain
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• v.24 no.1
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• pp.49-58
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• 1999

저자는 하악의 위치변화가 저작근에 미치는 영향을 근전도학적으로 평가하고자, 측두하악장애의 징후와 증상이 없는 정상성인 28명을 대상으로 중심위 교합장치(centric relation splint), 중심교합위 교합장치(centric occlusion splint), 전방 재위치 교합장치(anterior repositioning splint)를 장착시킨 상태에서 하악의 중심의, 중심교합위, 전방위률 유도한 후 최대 이악물기 상태의 좌우측 교근 및 전측두근의 근전도를 채득, 분석, 평가한 결과 다음과 같은 결론을 얻었다. 1. 전측두근에서 하악의 위치변화에 따른 최대 근활성도의 차이가 나타났으나(p<0.05), 교근에서는 나타나지 않았다. 2. 전측두근의 경우 중심교합위에서 최대 이악물기 상태의 최대 근활성도는 교합 장치물을 장착하지 않은 경우 및 중심위에서와 비교하여 감소하였다(p<0.05). 3. 전측두근의 경우 전방위에서 최대 이악물기 상태의 최대 근활성도는 교합 장치물을 장착하지 않은 경우 및 중심위에서와 비교하여 감소하였다(p<0.001). 4. 교근과 전측두근의 좌우 비대칭지수(asymmetry index)는 하악의 위치변화에 따른 차이가 나타나지 않았다.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.48 no.8
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• pp.641-651
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• 2020

This paper implements an antenna selection logic that automatically selects omni-directional antennas mounted on the top and bottom of an unmanned helicopter to maintain the link margin of the data link at 0dB or higher during flight. The selection criteria were derived by simulating and analyzing the radiation pattern. In addition, it is implemented to select the optimal antenna in real time during the flight by deriving the directivity angle function.