• 대한의용생체공학회:의공학회지
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• 제34권3호
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• pp.156-162
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• 2013

Moments of inertia of limb segments are essential to calculate parameters related to the segmental rotation. To analyze the human motion accurately and specifically, moments of inertia obtained from the individual are required. In this study, a simple method to determine a subject-specific moment of segmental inertia using a dynamometer is introduced. In order to evaluate the method, one male participated to test for his forearm plus hand on a commercial dynamometer. Three passive speeds, i.e. 240, 270, and $300^{\circ}/s$, were chosen to confirm whether the moment of inertia values at each speed approach to a fixed value. The same procedure was repeated on the day after to evaluate whether the method is reproducible. As the results, there were no significant differences among the speeds and between the days. The value of the moment of the forearm inertia was 0.216 $kg{\cdot}m^2$ that is apparently higher compared to values by previous models. Nonetheless, it seems to be acceptable based on our body mass index analysis using reported subject height and mass in each previous study. According to our results, the developed method could be useful to determine the segmental moment of inertia of an individual, showing no significant differences among the speeds and between the days. Thus, we believe that our results are reliable according to two appropriate evaluation procedures. This finding would be helpful to calculate segmental rotation related parameters of an individual.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2001년도 가을 학술발표회 논문집
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• pp.337-344
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• 2001

The application of mechanically stabilized earth wall(MSEW) with segmental front panel has been increasing in highway construction due to its cost-effectiveness. However, some failures during construction have been reported and many field engineers are reluctant to select this method for important structure. One of the main reasons may be that there is no moderate specification for design and construction of MSEW yet. This paper discussed the main results of analysis on a case of block-type segmental retaining wall in highway construction. Based on the results, some recommendations on design and construction method of MSEW are presented.

• The Journal of Advanced Prosthodontics
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• 제14권2호
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• pp.88-95
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• 2022

PURPOSE. This study investigated the accuracy of full-arch intraoral scans obtained by various scan strategies with the segmental scan and merge methods. MATERIALS AND METHODS. Seventy intraoral scans (seven scans per group) were performed using 10 scan strategies that differed in the segmental scan (1, 2, or 3 segments) and the scanning motion (straight, zigzag, or combined). The three-dimensional (3D) geometric accuracy of scan images was evaluated by comparison with a reference image in an image analysis software program, in terms of the arch shape discrepancies. Measurement parameters were the intermolar distance, interpremolar distance, anteroposterior distance, and global surface deviation. One-way analysis of variance and Tukey honestly significance difference post hoc tests were carried out to compare differences among the scan strategy groups (α = .05). RESULTS. The linear discrepancy values of intraoral scans were not different among scan strategies performed with the single scan and segmental scan methods. In general, differences in the scan motion did not show different accuracies, except for the intermolar distance measured under the scan conditions of a 3-segmental scan and zigzag motion. The global surface deviations were not different among all scan strategies. CONCLUSION. The segmental scan and merge methods using two scan parts appear to be reliable as an alternative to the single scan method for full-arch intraoral scans. When three segmental scans are involved, the accuracy of complete arch scan can be negatively affected.

• Earthquakes and Structures
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• 제17권4호
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• pp.411-424
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• 2019

In this study, a numerical model of a shield tunnel with an assembled segmental lining was built. The seismic response of the segmental lining of the section of the shield tunnel in Line 1 of the Chengdu Metro is analyzed as it passes through the interface of sand-cobble and mudstone layers. To do so, the node-stress seismic-motion input method was used to input the seismic motion measured during the 2008 Wenchuan earthquake, and the joint openings and dislocations associated with the earthquake action were obtained. With reference to the Ethylene-Propylene-Diene Monomer (EPDM) sealing gaskets used in the shield tunnels in the Chengdu Metro, numerical simulation was applied to analyze the contact pressure along the seepage paths and the waterproof property under different joint openings and dislocations. A laboratory test on the elastic sealing gasket was also conducted to study its waterproof property. The test results accord well with the numerical results and the occurrence of water seepage in the section of the shield tunnel in Line 1 of the Chengdu Metro during the 2008 Wenchuan earthquake was verified. These research results demonstrate the deformation of segmental joint under earthquake, also demonstrate the relationship between segmental joint deformation and waterproof property.

• 대한토목학회논문집
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• 제29권4A호
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• pp.407-419
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• 2009

이 연구는 조립식 기초부를 갖는 프리캐스트 세그먼트 PSC 교각의 지진거동을 파악하고 이에 대한 상세와 기초자료를 제공하는데 그 목적이 있다. 6개의 프리캐스트 세그먼트 PSC 교각 실험체에 일정 축하중 하에서 횡방향 반복하중을 가하는 준정적 실험을 수행하였다. 사용된 프로그램은 철근콘크리트 구조물의 해석을 위한 RCAHEST이다. 사용된 부착 또는 비부착 텐던요소는 유한요소법에 근거하며 프리스트레스트 콘크리트 부재의 콘크리트와 텐던의 상호작용을 구현할 수 있다. 수정된 접합요소는 세그먼트 접합부의 비탄성거동을 예측할 수 있다. 이 연구에서는 조립식 기초부를 갖는 프리캐스트 세그먼트 PSC 교각의 실험적, 해석적 결과를 제시하였다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2004년도 추계 학술발표회 제16권2호
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• pp.89-92
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• 2004

Precast Segmental method was developed in germany 1950's. This method has been adoptted in long span girder mainly owing to easy construction effect. But, so far, The limit exists that this method is constructed in a portion of span and hard conveyance and foundation. This study was performed to analysis behavior difference of two rectangular section girder, spliced girder that was jointed 5-sliced 0.8m segment and monolithic girder that was produced in one body 4m span.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2005년도 지반공학 공동 학술발표회
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• pp.681-688
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• 2005

The Green Wall is the highest eco-system among a segmental retaining wall systems. Recently, the demand of high segmental retaining wall (SRW) is increased in domestic. The soil nailing system is applied in order to maintain the high SRW stability for steeper slope. However, the proper design approach that can consider the earth pressure reduction effects in soil nailing system has not been proposed. Hence, the purpose of this study was to provide the design and analysis technique of the segmental retaining wall reinforced by soil nailing. Also, in this study, various parametric studies using numerical method as shear strength reduction (SSR) technique were carried out. In the parametric study, the length ratio and the bond ratio of the soil nailing were changed to identify the earth pressure reduction effect of the retaining wall reinforced by soil nailing.

• 한국지진공학회논문집
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• 제13권2호
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• pp.15-27
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• 2009

이 연구는 지진하중을 받는 프리캐스트 세그먼트 PSC 교각의 지진거동을 파악하는데 그 목적이 있다. 사용된 프로그램은 철근콘크리트 구조물의 해석을 위한 RCAHEST(Reinforced Concrete Analysis in Higher Evaluation System Technology)이다. 사용된 부착 또는 비부착 텐던요소는 유한요소법에 근거하며 프리스트레스트 콘크리트 부재의 콘크리트와 텐던의 상호작용을 구현할 수 있다. 그리고 수정된 접합요소는 세그먼트 접합부의 비탄성거동을 예측할 수 있다. 동적 평형방정식의 해는 HHT(Hilber-Hughes-Taylor) 법에 의한 수치적분으로 구하였다. 제안된 해석기법은 수치예제에 대하여 입력지진파에 따른 지진거동을 비교적 정확하게 예측하였다.

• 대한토목학회논문집
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• 제10권2호
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• pp.49-58
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• 1990

캔틸레버 시공법에 의해 가설되는 프리스트레스트 콘크리트 교량의 시간 단계별 장기 처짐을 정확하게 해석하지 위해 프리스트레스트 콘크리트의 시간 의존적 재료 특성과 캔틸레버 공법에 있어서의 분할시공 과정을 고려할 수 있는 해석 모델을 개발하고, 이에 기초하여 콤퓨터 프로그램을 작성하였다. 본 프로그램에서는 시간의 경과에 따른 콘크리트의 크리프, 건조 수축 및 탄성 계수의 변화 그리고 PS 강재의 리락세이션을 고려한다. 그리고 시공 단계별 세그먼트의 발생, 다단계 프리스트레싱 그리고 지점조건의 변화를 고려한다. 또한 철근으로 인한 단면의 강성 증가를 고려하고 전단변형의 영향을 고려하여 보다 정확하게 해석할 수 있도록 하였다. 본 프로그램을 이용하여 다경간 PS 콘크리트 교량을 해석함으로써, 프로그램의 실제 적용성과 캔틸레버공법에 의한 교량의 거동 특성을 규명하고자 하였다.

• 대한의생명과학회지
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• 제11권2호
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• pp.193-199
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• 2005

The present study was performed to assess peripheral neural involvement by exposure to hand-arm vibration. Segmental sensory nerve conduction in the median and ulnar nerves were measured in shipyard workers exposed to vibration. The subjects were 47 male adults exposed to hand-arm vibration and 7 healthy male controls. The subjects underwent an extensive bilateral neurophysiological examination. Sensory compound nerve action potential (SNAP) of the median and ulnar nerves in palm-finger and wrist-palm segments were measured by antidromic method. And SNAP of the median and ulnar nerves in wrist-proximal finger and wrist-distal finger segments were measured by orthodromic method. Result of sensory nerve conduction study was abnormal in 31 patients $(66\%)$ and normal in 16 patients $(34\%)$ of subjects. The pathological pattern in the hand-arm vibration exposed group was 13 patients $(28\%)$ of carpal tunnel syndrome, 18 patients $(38\%)$ of distal sensory neuropathy, 7 patients $(15\%)$ of multifocal and 1 patient $(2\%)$ of Guyon syndrome. The present study indicates that vibration-induced nerve impairments exist both in the finger-palm and palm-wrist segment of median and ulnar sensory nerves. The results suggest that segmental sensory nerve conduction study would be useful as objective indication of peripheral nerve impairment induced by the hand-arm vibration.