• Journal of Ginseng Research
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• 제40권4호
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• pp.462-465
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• 2016

In the present study, we investigated whether treatment with GBCK25 facilitated the recovery of hemodynamic parameters, left ventricle systolic pressure, left ventricular developed pressure, and electrocardiographic changes. GBCK25 significantly prevented the decrease in hemodynamic parameters and ameliorated the electrocardiographic abnormality. These results indicate that GBCK25 has distinct cardioprotective effects in rat heart.

• Geomechanics and Engineering
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• 제36권6호
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• pp.575-587
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• 2024

The contact pressure between the surrounding rock and the support is an important indicator of the surrounding rock pressure. There has been a bottleneck in the prediction of contact loads between surrounding rock and primary support in deep-buried mountain tunnels. The main reason is that a reliable method wasn't existed to quantify the contact loads. This study had been taken into account the flexible support role of the primary support, and the fitting curve of surrounding rock deformation for dynamic tunnel construction was proposed. New formulas for the calculation of contact loads between surrounding rock and primary support were obtained by inversion. Comparative analysis of the calculation results with numerical simulation verified the reliability of the calculation method in this study. It can be seen from the analyses that the contact load between surrounding rock and primary support increases, remains unchanged and decreases during acceleration, uniform velocity and deceleration, respectively, and the deformation of the surrounding rock in the acceleration and deceleration stages cannot completely converted into contact loads. The contact loads between surrounding rock and primary support of medium-strength and weak surrounding rock tunnels are generally within 150 kPa and 1 MPa, respectively. For tunnels with weak surrounding rock, advanced support can be installed to reduce the unique release coefficient λ₀ and the value of the constant D, with the purpose of reducing the contact loads between surrounding rock and primary support. Changes in support parameters have a small effect on the contact loads between surrounding rock and primary support, but increase or decrease the safety factor, resulting in a waste of resources or a situation that threatens the safety of the support. The results of this research provide guidance for the prediction of contact loads between surrounding rock and primary support for dynamic tunnel construction.

• 한국정보과학회논문지:정보통신
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• 제34권1호
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• pp.73-80
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• 2007

본 논문은 인터넷 멀티미디어 응용을 위한 유력한 세션 제어 프로토콜인 SIP(Session Initiation Protocol)의 동적인 QoS(Quality of Service) 요구 사항을 광대역 접속망(Broadband Access Network)에서 지원하는 방안에 대해 논한다. 먼저 SIP QoS를 지원하기 위한 광대역 접속망의 구조와 동작 모델을 제시하고, 동적 QoS를 지원하는 SIP 시그널링을 IP QoS 메카니즘으로 변환하는 과정을 제시한다. IntServ 구조의 복잡성 문제를 고려하여 본 논문은 DiffServ 기반의 IP QoS 구조를 채택하고, 동적 SIP QoS에 대응되는 동적 DiffServ 지원을 위해 COPS(Common Open Policy Service)와 COPS-PR 프로토콜 기반의 시그널링 메카니즘을 제안한다. 또한 본 논문은 현재 급속히 확산되고 있는 메트로 이더넷(Metro Ethernet) 기반의 802.1 D/Q QoS를 지원하는 광대역 접속망을 가정하고, SIP QoS 매개변수를 DiffServ의 트래픽 등급으로 변환하는 방안, 그리고 DiffServ의 트래픽 등급을 802.1 D/Q 메트로 이더넷에서 지원하는 방안을 제시한다.

• 한국가스학회지
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• 제18권5호
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• pp.6-11
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• 2014

차량용 LNG 연료 용기의 내진동 단열 지지구조 최적화 설계 개발을 위하여 종래의 해외특허구조 설계를 기본으로 한 특성요인도 분석으로 용기의 내조 및 외조 지지부 구조설계의 주요 설계 인자를 도출하였다. 도출된 설계인자 중에서 우선적으로 지지 봉재의 직경과 단열 격판 연결부 곡률을 대상으로 하여 최적화를 수행하였다. 차량용 LNG 연료 용기 설계안에 대한 평가를 위해 설계안을 MSC/MARC 상용유한 요소해석 패키지를 활용하여 유한요소 모델링하여 진동모드해석과 열전달 및 열응력해석을 수행하였다. 최적화 설계 결과를 통하여 도출된 설계안은 고유진동해석을 통한 1차 모드 고유진동수(1st Mode Natural Frequency), 열전달해석을 통한 초저온 용기 내조 외조간 지지부를 통한 총전열량 및 열응력해석을 통한 최대 Von-Mises 응력이 모두 설계 목표치를 만족하였으며, 개발된 설계안에 따라 차량용 LNG 연료 용기의 제작하여 3차원 진동 시험과 단열성능 시험을 통해 설계를 검증하였다.

• 대한인간공학회지
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• 제32권3호
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• pp.245-252
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• 2013

Objective: This paper analyzes the changes on stride parameters, joint angles, and trajectories of the body parts due to high heels during walking and explains the causal relationship between the changes and high heels. Background: This study aims to indicate the comprehensive gait changes by high heels on the whole body for women wearing high heels and researchers interested in high-heeled walking. Method: The experiment was designed in which two different shoe heel heights were used for walking (1cm, 9.8cm), and twelve women participated in the test. In the experiment, 35 points on the body were tracked to extract the stride parameters, joint angles, and trajectories of the body parts. Results: Double support time increased, but stride length decreased in high-heeled walking. The knee inflexed more at stance phase and the spine rotation became more severe. The trajectories of the pelvis, the trunk and the head presented outstanding fluctuations in the vertical direction. Conclusion: The double support time and the spine rotation were changed to compensate instability by high heels. Reduced range of motion of the ankle joint influenced on the stride length, the knee flexion, and fluctuations of the body parts. Application: This study can provide an insight of the gait changes by high heels through the entire body.

• 응용통계연구
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• 제22권1호
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• pp.221-235
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• 2009

This manuscript illustrates the comparative study between ARIMA and Exponential Smoothing modeling to develop forest fire forecasting system using different weather parameters. In this paper, authors have developed the most suitable and closest forecasting models like ARIMA and Exponential Smoothing techniques using different weather parameters. Authors have considered the extremes of the Wind speed, Radiation, Maximum Temperature and Deviation Temperature of the Summer Season form March to June month for the Ranchi Region in Jharkhand. The data is taken by own resource with the help of Automatic Weather Station. This paper consists a deep study of the effect of extreme values of the different parameters on the weather fluctuations which creates forest fires in the region. In this paper, the numerical illustration has been incorporated to support the present study. Comparative study of different suitable models also incorporated and best fitted model has been tested for these parameters.

• 한국통신학회논문지
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• 제37권3C호
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• pp.224-232
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• 2012

Priority MAC is an important issue in every communication system when we consider differentiated service applications. In this paper, we propose a mechanism to support priority MAC based on multi-parameters for IEEE 802.15.7 visible light communication (VLC). By using three parameters such as number of backoff times (NB), backoff exponent (BE) and contention window (CW), we provide priority for multi-level differentiated service applications. We consider beacon-enabled VLC personal area network (VPAN) mode with slotted version for random access algorithm in this paper. Based on a discrete-time Markov chain, we analyze the performance of proposed mechanism under non-saturation environments. By building a Markov chain model for multi-parameters, this paper presents the throughput and transmission delay time for VLC system. Numerical results show that we can apply three parameters to control the priority for VLC MAC protocol.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1997년도 봄 학술발표회 논문집
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• pp.139-146
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• 1997

The main purpose of this paper is to investigate the near-optimal parameters of continuous beam subject to a moving load. The computer-aided optimization technique is used to obtain the near-optimal parameters. The computer program is developed to obtain the natural frequency parameters and the forced vibration responses to a transit point load for the continuous beam with variable support spacing, mass and stiffness. The optimization function to describe the design efficiency is defined as a linear combination of four dimensionless span characteristics: the maximum dynamic stress; the stress difference between span segments; the rms deflection under the transit point load; and the total span mass. Studies of three span beams show that the beam with near-optimal parameters can improve design efficiency by 12 to 24 percent when compared to a reference configuration beams of the same total span length.

• Geomechanics and Engineering
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• 제38권3호
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• pp.319-334
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• 2024

The current theories on the interaction between surrounding rock and support in deep-buried tunnels do not consider the form of pre-reinforcement support or the flexibility of primary support, leading to a discrepancy between theoretical solutions and practical applications. To address this gap, a comprehensive mechanical model of the tunnel with pre-reinforced rock was established in this study. The equations for internal stress, displacement, and the radius of the plastic zone in the surrounding rock were derived. By understanding the interaction mechanism between flexible support and surrounding rock, the three-dimensional construction analysis solution of the tunnel could be corrected. The validity of the proposed model was verified through numerical simulations. The results indicate that the reduction of pre-deformation significantly influences the final support pressure. The pre-reinforcement support zone primarily inhibits pre-deformation, thereby reducing the support pressure. The support pressure mainly affects the accelerated and uniform movement stage of the surrounding rock. The generation of support pressure is linked to the deformation of the surrounding rock during the accelerated movement stage. Furthermore, the strength of the pre-reinforcement zone of the surrounding rock and the strength of the shotcrete have opposite effects on the support pressure. The parameters of the pre-reinforcement zones and support materials can be optimized to achieve a balance between surrounding rock deformation, support pressure, cost, and safety. Overall, this study provides valuable insights for predicting the deformation of surrounding rock and support pressure during the dynamic construction of deep-buried weak rock tunnels. These findings can guide engineers in improving the construction process, ensuring better safety and cost-effectiveness.

• 한국강구조학회 논문집
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• 제16권3호통권70호
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• pp.377-385
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• 2004

본 논문에서는 강판-콘크리트 벽체구조에 부착되는 기기를 지지하기 위하여 설치되는 지지대와 벽채와의 접합 성능을 파악하기 위하여 구조실험 및 유한요소해석을 수행하였다. 구조실험은 9개의 시험체를 제작하여 파괴모드 및 최대내력을 파악하였으며 유한요소해석모델을 작성하여 이를 실험결과와 비교 검증한 후 강판두께, 스터드 볼트 간격, 지지대의 위치 및 크기 등의 영향인자가 벽체 접합부의 거동 및 내력에 미치는 변화를 살펴보았다. 해석 시험체의 하중-변형의 관계로부터 시험체의 항복내력 및 최대내력을 정의 하였으며 향후 항복선 해석을 위한 토대를 마련하였다.