• Structural Monitoring and Maintenance
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• 제5권3호
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• pp.363-377
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• 2018

The proper functioning of critical points on transport infrastructure is decisive for the entire network. Tunnels and bridges certainly belong to the critical points of the surface transport network, both road and rail. Risk management should be a holistic and dynamic process throughout the entire life cycle. However, the level of risk is usually determined only during the design stage mainly due to the fact that it is a time-consuming and costly process. This paper presents a simplified quantitative risk analysis method that can be used any time during the decades of a tunnel's lifetime and can estimate the changing risks on a continuous basis and thus uncover hidden safety threats. The presented method is a decision support system for tunnel managers designed to preserve or even increase tunnel safety. The CAPITA method is a deterministic scenario-oriented risk analysis approach for assessment of mortality risks in road tunnels in case of the most dangerous situation - a fire. It is implemented through an advanced risk analysis CAPITA SW. Both, the method as well as the resulting software were developed by the authors' team. Unlike existing analyzes requiring specialized microsimulation tools for traffic flow, smoke propagation and evacuation modeling, the CAPITA contains comprehensive database with the results of thousands of simulations performed in advance for various combinations of variables. This approach significantly simplifies the overall complexity and thus enhances the usability of the resulting risk analysis. Additionally, it provides the decision makers with holistic view by providing not only on the expected risk but also on the risk's sensitivity to different variables. This allows the tunnel manager or another decision maker to estimate the primary change of risk whenever traffic conditions in the tunnel change and to see the dependencies to particular input variables.

• 한국통신학회논문지
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• 제41권8호
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• pp.928-941
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• 2016

유선 데이터 네트워크(wired data network) 영역에서 가장 많은 에너지를 요구하는 영역은 액세스 네트워크(access network) 영역이다. 오늘날 그린 네트워킹(Green networking)은 유선 데이터 네트워크에서도 통합적인 에너지 관리를 통해 에너지 낭비와 $CO_2$ 배출 감소를 유도하기 위해 주요 관심분야가 되었다. 그러나 유선 액세스 네트워크의 에너지 소모량과 $CO_2$ 배출에 의한 환경적 영향에 대해서는 널리 알려져 있지 않으며, 그에 따른 범용적이고 정량적인 평가 기준도 매우 부족하다. 본 논문에서는 유선 액세스 네트워크의 에너지 소모량을 추정하는 기존의 모델링 기법들의 문제점을 비교 분석하고 하향식(top-down) 접근법을 이용하여 대규모 유선 액세스 네트워크의 에너지 소모량을 추정하는 모델링 기법을 제안한다. 또한 제안 모델로부터 도출된 추정치를 이용하여 액세스 네트워크들이 환경에 미치는 영향도를 산출하는 모델을 제안한다. 그리고 실제 사례를 적용하여 기존 모델과 제안 모델로부터 산출한 추정치와 해당 사례에 대한 기존의 조사와 실측 데이터와 비교 평가 한다.

• 전자공학회논문지S
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• 제35S권2호
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• pp.58-69
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• 1998

A contrp; suste, fpr SCARA robot is designed for implememting a robust dynamic control algorithm. this study forcuses on the use of DSPs in the design of joint controllers and interfaces in between the host cotroller and four joint controllers and in between the joint controllers and four servo drives. The mechanical body of SCARA robot and the servo drives are selected from the commercially available ones. The four joint controllers, assigned to each joint one by one, are combined into a common system through a mother board hardwarewise and through the global memeory softwarewise. The mother board is designed to connect joint controllers onto the board through the slots adopting PC/104 bus structures. And, the global memory stores the common data which can be shared by joint controllers and the host computer directly, which virtually combines the whole system into one. To demonstrate the performance and efficienty of the sytem, a robust inverse dynamic algorithm is proposed and implemented for a faster and more precise control. The robust inverse dynamic algorithm is basically derived from an inverse dynamci algorithm and a PID compensator. Based upon the derived dynamic equitions of SCARA robot, the inverse dynamic algorithm is intitially implemented within 0.3 msec of the control cycle in this system. The algoithm is found to be not accurate enough for the high speed and precision tasks due to inherent modelling errors and time-varying factors. Therefore, a variable PID algorithm is combined with the inverse dynamic algorithm to support robustness of control performance. Experimental datfor the proposed algorithm are presented and compared with the result obtained from PID and inverse dynamic algorithm.

• 콘크리트학회지
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• 제7권3호
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• pp.175-186
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• 1995

매시브 콘크리트 구조물의 균열선단의 응력확대계수를 구하는 데 표면적분법을도입하였다. 표면적분법은 경로적분인 J-적분법을 근저로 하여 유도가 된다. J-적분법에서는 균열면의 압력고 구조물의 물체력을 고려할 수가 없는 반면에 본 이론은 이러한 일반 하중조건을 고려할 수가 있으므로 보다 정확한 균열선단부의 응력상태를 고찰하는데 유용하다. 또한 균열선단부의 특이성을 표현하기 위해 특이요소를 사용하거나 균열선단부의 세밀한 요소분할을 요하는 등의 불편함을 제거할 수 있는 기법이다. 본 이론을 바탕으로 응력확대계수$K_I$, $K_{II}$를 구하는 프로그램을 작성하였으며 8절점 등매개 변수요소를 사용하여 $K_I$, $K_{II}$를 검증하였으며 실제 댐 구조물에 적용시켜 응력확대계수의 변화를 살펴보았다.

• 동의생리병리학회지
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• 제29권4호
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• pp.305-312
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• 2015

Paeonol is a major component found in the Paeoniaceae family such as Paeonia suffruticosa Andrews. Paeonia suffruticosa Andrews has traditionally been used to enhance blood flow and relieve joint pain in east Asian countries including China, Korea and Japan. Current research has shown that paeonol blocked the voltage-gated sodium channel and L-type calcium channel. However, there is a lack of research to reveal the relation between cardiac function and blockade of ion channels by paeonol. Therefore, the aim of this study is to investigate whether paeonol has anti-arrhythmic effects via modulating cardiac ion channels. It is collected that the effects of paeonol on multiple ion channels such as the fast sodium channel and L-type calcium channel from published papers. To incorporate the information on multi-channel block, we computed the effects using the mathematical cardiac model of the guinea-pig and rat ventricular cells (Noble 1998 and 1991 model) and induced early after-depolarizations (EADs) to generate an arrhythmia in the whole heart. Paeonol slightly shortened the action potential duration in the normal cardiac ventricular action potential by the inhibition of sodium channel and L-type calcium channel. Paeonol presented the protective effect from EADs by the inactivation of sodium channel but not L-type calcium channel. Paeonol did not show any changes when it treated on normal ventricular cells through the inhibition of sodium channel, but the protective effect of paeonol through sodium channel on EADs was dose-dependent. These findings suggest that paeonol and its original plant may possess anti-arrhythmic activity, which implies their cardioprotective effects.

• 시스템엔지니어링학술지
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• 제12권1호
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• pp.59-71
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• 2016

The Nuclear and Fossil Steam Turbines record a considerable number of failures annually. Some of these failures reported are as result of blade failure. The failure of the L-0 blade in a Steam Turbine is one of the most reported blade failure in Nuclear and Fossil steam turbines. This paper seeks to identify the best Non Destructive Evaluation (NDE) method or methods to be used in the steam turbine L-0 blades inspection process. The development of systems engineering processes presents an opportunity to apply NDE inspection to the L-0 blades. This process apply computer modelling of the L-0 using ANSYS and by simulating the stresses experienced by the L-0 blade during operation it is possible to identify the most susceptible areas for crack formation and growth. The results from these models compared to industry data for validation. The analysis of these results used to predict the most probable failure location and failure modes. Therefore NDE inspection can be applied to these areas with greater degree of accuracy. This would be beneficial in the increasing the accuracy in the detection of cracks and hence save inspection time and the overall inspection cost. Furthermore, not only the location for crack formation and NDE inspection determined but also best the NDE inspection technique/techniques to be applied appropriately on the L-0 blade are prescribed.

• 한국컴퓨터정보학회지
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• 제14권2호
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• pp.147-152
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• 2006

2D에서 3D로 이동하고 있는 현재의 GIS는 자료 크기가 기하급수적으로 커지고 이로 인해 처리속도가 느려지고 있으며 사용자의 실시간 렌더링(Rendering) 요구는 커지고 있다. 대용량의 공간자료에 대한 처리속도, 3 차원 처리기술, 가상현실 처리기술 등의 제약조건과 3차원 GIS를 가시화하기 위해서는 방대한 양의 데이터를 처리하기 위한 시간과 비용이 많이 과다하게 발생하는 문제점을 가지고 있다. 본 논문에서는 이러한 문제를 해결하고 웹 상에서 가상 캠퍼스(Virtual Campus)를 구현하기 위해 위성 및 항공으로부터 획득한 DEM 데이터를 VRML로 가시화하여 3차원으로 가시화된 지형 정보를 구하고, 모델링 툴을 이용하여 건물 및 도로에 대한 3차원의 캠퍼스 정보를 획득하게 된다. 이렇게 획득된 3차원의 정보를 보다 사실감 있는 질감과 재질을 표현하기 위하여 실물에 가까운 텍스처 맵핑 작업을 통해 웹 기반의 3차원 가상 캠퍼스를 구현할 수 있었다.

• 한국산업보건학회지
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• 제7권2호
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• pp.289-297
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• 1997

Work-related low back pain(below LBP) is one of the major cause of morbidity, disability, limitation of activity and economic loss. Therefore the work-related LBP is one of the major issue in the field of industrial safety and health. This study was performed for detecting the risk factors and proposing the effective control programs of work-related LBP. The subjects were male workers employed at the welding and metal factory. The data was collected by self-reported questionnaire, interview and checking abdomen muscular and grasping power for two days on October, 1993. The contents of questionnaire were as follow: the experience of LBP, general characteristics, physical characteristics, employment status, type of work and working environment. The number of cases was 104 with a history of work-related LBP, so the prevalence of work-related LBP was 35.0%, and the number of controls was 140 without any history of LBP. As a result, marital status, educational level, abdomen muscular power, tenure, category of job, satisfaction of job, working posture, satisfaction for table and chair and lifting materials showed a statistical significance between the case and control groups. 284 Lifting jobs were quantified by NIOSH lifting equation method and ergonomic computer modelling methods. There were no significant differences in the action limit and disc compression force between group with LBP and without LBP. But in the lifting frequency and cumulative disc compression force there were significant differences. Therefore work-related LBP should be prevented by the ergonomic and environmental control.

• International Journal of CAD/CAM
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• 제6권1호
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• pp.9-17
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• 2006

Performing inspections for Hull Condition Monitoring and Assessment as stipulated in IACS unified requirements and IMO's Condition Assessment Scheme (CAS) IMO Resolution MEPC.94(46), 2001, Condition Assessment Scheme, IMO Resolution MEPC.111(50), 2003, Amendments to regulation 13G, addition of new regulation 13H involves a huge amount of measurement data to be collected, processed, analysed and maintained. Information to be recorded consists of thickness measurements and visual assessment of coating and cracks. The amount of data and increasing requirements with respect to condition assessment demand efficient computer support. Currently, due to the lack of standardization for this kind of data, the thickness measurements are recorded manually on ship drawings or tables. In this form, handling of the measurements is tedious and error-prone and assessment is difficult. Data reporting and analysis takes a long time, leading to some repairs being performed only at the next docking of the ship or making an additional docking necessary. The recently started ED funded project CAS addresses this topic and develops-as a first step-a data model for Hull Condition Monitoring and Assessment (HCMA) based on XML-technology. The model includes simple geometry representation to facilitate a graphically supported data collection as well as an easy visualisation of the measurement results. In order to ensure compatibility with the current way of working, the content of the data model is strictly confined to the requirements of the measurement process. Appropriate data interfaces to classification software will enable rapid assessment by the classification societies, thus improving the process in terms of time and cost savings. In particular, decision-making can be done while the ship is still in the dock for maintenance.

• 대한전자공학회논문지
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• 제25권10호
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• pp.1173-1182
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• 1988

보행로보트에 있어서 다리의 기구적 특성은 안정도, 에너지 효율 및 걷는 영역 등에 영향을 준다. 보행로보트 중에서 안정도 여유가 비교적 큰 사각보행로보트는 보폭이 크다. 그리고 수직운동과 수평운동이 서로 분리되어 있는 팬토그래프 구조의 다리를 갖는 보행로보트는 기구적인 복잡성으로 인하여 움직임을 예상하기가 어렵게 된다. 따라서, 보행로보트의 3차원적인 이동을 해석하기 위하여 그래픽스를 이용한 방법이 중요하게 쓰일 수 있다. 본 논문에서는 서로 다른 조인트 구동방식을 갖는 세 개의 사각보행로보트를 모델링하고, 각각에 대하여 몸의 중심으로 표시된 경로로써 작업지시를 하여 걷는 모습을 애니메이션 함으로써 그 기구적인 특성을 해석할 수 있게 하였다. 그리고 회전걸음이나 옆걸음을 위하여 다리 제어를 하였고, 조인트의 이동에 대한 정보를 위하여 Sun-3 시스템에서의 윈도우를 이용하였다.