• 한국환경과학회지
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• 제19권7호
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• pp.917-929
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• 2010

This paper aims to find out the statistical characteristics of the weather related railroad accidents and incidents. Data from Korea Railroad Operation Information System(KROIS) and Korea Railroad Accidents reports during 1996-2008 were used to investigate the occurrence frequency of railroad accidents and operation obstacles and their association with weather phenomena. The results are as follows; The occurrence frequency of railroad accidents and operation obstacles decrease gradually, and most of railroad accidents is a railroad traffic accidents. The amount of damages by a railroad weather-related accidents is higher than those of the railroad accidents and operation obstacles. It was also found that weather events influencing the railroad weather-related accidents and incidents are rainfall, snowfall, lightning, winds. And they caused a railroad weather-related accidents and incidents, such as railway obstruction, signal failure, and power supply failure. Therefore we need research about threshold review and a quantitative and qualitative analysis of a railroad weather-related accidents and incidents according to climate change.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.2325-2330
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• 2005

A potential field method for solving the problem of path planning based on global and local information for a mobile robot moving among a set of stationary obstacles is described. The concept of various method used path planning is used design a planning strategy. A real human living area is constructed by many moving and imminence obstacles. Home service mobile robot must avoid many obstacles instantly. A path that safe and attraction towards the goal is chosen. The potential function depends on distance from the goal and heuristic function relies on surrounding environments. Three additional combined methods are proposed to apply to human living area, calibration robots position by measured surrounding environment and adapted home service robots. In this work, we proposed the application of various path planning theory to real area, human living. First, we consider potential field method. Potential field method is attractive method, but that method has great problem called local minimum. So we proposed intermediate point in real area. Intermediate point was set in doorframe and between walls there is connect other room or other area. Intermediate point is very efficiency in computing path. That point is able to smaller area, area divided by intermediate point line. The important idea is intermediate point is permanent point until destruction house or apartment house. Second step is move robot with sensing on front of mobile robot. With sensing, mobile robot recognize obstacle and judge moving obstacle. If mobile robot is reach the intermediate point, robot sensing the surround of point. Mobile robot has data about intermediate point, so mobile robot is able to calibration robots position and direction. Third, we gave uncertainty to robot and obstacles. Because, mobile robot was motion and sensing ability is not enough to control. Robot and obstacle have uncertainty. So, mobile robot planed safe path planning to collision free. Finally, escape local minimum, that has possibility occur robot do not work. Local minimum problem solved by virtual obstacle method. Next is some supposition in real living area.

• 전자공학회논문지SC
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• 제43권3호
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• pp.31-40
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• 2006

이동로봇의 경로 설정과 장애물 회피에 관한 문제는 이동로봇을 제어하기 위한 기본적인 문제로서 지금까지 많은 연구가 진행되어 오고 있다. 다양한 센서들로부터 얻어진 정보는 로봇이 진행하기 위한 경로에 대한 결정과 장애물에 대한 정보를 제공해준다. 제한 조건이 존재하는 경우에서 그 상황에 알맞은 방법들이 대부분이며, 다른 상황을 해결하기에는 어려움이 있다. 또한, 최적화된 경로에 대한 좋은 결과를 만들기 위해서는 복잡한 계산 과정을 통해서 시간 지연이 발생하게 된다. 이와 같은 처리 방법은 움직이는 장애물의 회피와 같이 빠른 처리를 필요로 하는 상황에서 단점으로 작용한다. 본 논문에서는 장애물과 이동 가능한 경로들의 영역을 작은 영역들이 분포하는 공간으로 변형하고 이와 같이 구성된 공간에서 밀도와 연결 상태를 통해 이동 로봇이 진행 할 수 있는 최단 경로를 결정한다. 제안된 방법을 통해 작은 영역들은 자신의 번호를 가지게 되며, 주변 영역들의 개수를 통해 이동 경로를 결정하게 된다.

• 한국게임학회 논문지
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• 제8권3호
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• pp.3-14
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• 2008

본 연구는 영화와 같은 다른 문화콘텐츠의 장르 구분을 수용하면서 애매하고 모호하게 지속되고 있는 게임 장르의 구분에 대한 새로운 시도이다. 게임 그 자체만을 대상으로 장르 구분을 할 경우 먼저 고려하게 되는 것은 게이머의 행위에 기반한 장르구분과 텍스트에 기반한 장르구분이 있을 수 있다. 연구 결과 게이머의 행위에 기반한 장르구분은 행위의 의미의 중복성과 이에 대한 객관적인 판단기준의 부재에 따라 그 한계를 드러낸다. 이에 반해서 상대적으로 객관적인 기준을 제시할 수 있는 게임 텍스트에 기반한 장르 구분은 3단계를 거쳐서 7개의 유형인 물리적 장애물 게임, 물리-인지적 장애물 게임, 인지적 장애물 게임, 인지-물리적 장애물 게임, 운용 게임, 대전 게임, 순위 게임으로 나뉘어진다. 그리고 각 유형의 게임들은 고유의 관습과 성격을 공유하고 있다.

• 항공우주정책ㆍ법학회지
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• 제34권1호
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• pp.159-201
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• 2019

1951년 부속서 14, 제1권의 제정과 함께 활주로 주변의 제한표면이 설정된 이후, 항공기술과 항법 성능은 눈부신 성장을 이루었으며, 이를 통한 항행의 안전성과 정밀성은 크게 향상되었다. 그러나, 항공기의 안전한 비행을 위한 주변 장애물에 대한 제한은 변함없이 유지되고 있다. 공항과 주변을 비행하는 항공기의 안전확보를 위한 표준과 기준에 대해서는 부속서 11, 항공교통업무(Annex 11, Air Traffic Services)와 부속서 14, 비행장(Annex 14, Aerodromes) 등에서 명시하고 있다. 특히, 항공기와 지상 장애물의 충돌방지를 위한 수목 산악 구릉 등 자연장애물과 건축물 구조물 등의 인공 장애물 등 공항 주변 장애물의 제한에 대해서는 부속서 14, 제1권에서 그 기준을 제시하고 있다. 반면, 부속서 14, 제1권은 장애물 제한표면의 적용에 있어, 항공학적 검토를 통해 항공기 운항의 안전과 규칙성을 저해하지 않는다고 판단되는 경우에는 기준을 위배하는 장애물을 제거하지 않을 수 있다고 하여 예외 기준을 적용하고 있다. 항공학적 검토는 미국, 캐나다 및 유럽 등 여러 국가에서 도입 시행하고 있었으며, 이에 따라 우리나라는 2008년 5월, (구(舊))항공법 시행규칙의 일부 조항을 신설 및 개정하고, 항공학적 검토지침을 제정하여 예외적 사항을 인정하게 되었다. 그러나, ICAO는 항공학적 검토에 관한 절차와 방법에 대해 구체적 지침을 제공하지 않고 있어 항공학적 검토를 시행하는 국가는 자체적인 절차와 방법을 마련하여 적용하는 실정이다. 이러한 현실적 상황을 반영하듯이, 제12차 세계항행회의와 제38차 총회에서 체약국은 현행 장애물 제한표면에 관한 기준과 항공학적 검토의 방법에 대한 재검토를 요구하였으며, ICAO는 관련 전담팀을 구성하여 새로운 기준 마련에 착수하였다. 이에 본 연구는 장애물 제한표면과 항공학적 검토에 관한 국제적 변화의 움직임에 맞추어, 현행 장애물 제한표면과 높이 제한에 관한 국내 외 기준을 비교 분석하는 한편, 항공학적 검토에 관한 방법과 절차 및 제도에 대해 살펴보고자 한다. 아울러, 장애물의 영향성을 평가함에 항공학적 검토가 현실적이고 보편적으로 활용될 것으로 예상하는바, 현행 항공학적 검토에 항적 자료를 활용한 정량적 분석방법의 개발과 함께 항공학적 검토의 제도적 개선을 제언하고자 한다.

• 품질경영학회지
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• 제31권2호
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• pp.82-97
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• 2003

The study attempts to review TQM models used in the health care sector and the obstacles to the application of TQM in the sector. Even though the TQM models in the manufacturing and service sectors were successfully applied, the applicability of TQM in the health care sector is still in question. The reason is the unique characteristics of the medical sector such as medical and management practices. The most of the TQM models in the health care sector come from manufacturing industries. The importance of the professional groups is, however, more emphasized in the sector than in manufacturing sector. The role of the groups are idiosyncratic to the sector. They generate some obstacles to the application of TQM in the sector. The barriers include cultural obstacles of health care organization. It naturally follows that the TQM in the health care sector requires the change of the organizational culture of the sector. The culture embraces the norms, rules, regulations, compensation system, morale, practices, and common experiences. To change the culture needs long term effort and modification of the rules, regulations, compensation system, and practices. It also requires staffs' training in the problem solving methods. The TQM in the health care sector needs that the interested parties should change. Since doctors group and nurses group are controlled in the bureaucratic and authoritative manner, they should learn the problem solving techniques which require the interaction with other groups. The management also needs to learn management skills and get thorough training on them.

• 한국정밀공학회지
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• 제15권1호
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• pp.78-86
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• 1998

This paper presents a numerical method of the minimum-time trajectory planning for a robot manipulator amid obstacles. Each joint displacement is represented by the linear combination of the finite-term quintic B-splines which are the known functions of the path parameter. The time is represented by the linear function of the same path parameter. Since the geometric path is not fixed and the time is linear to the path parameter, the coefficients of the splines and the time-scale factor span a finite-dimensional vector space, a point in which uniquely represents the manipulator motion. The displacement, the velocity and the acceleration conditions at the starting and the goal positions are transformed into the linear equality constraints on the coefficients of the splines, which reduce the dimension of the vector space. The optimization is performed in the reduced vector space using nonlinear programming. The total moving time is the main performance index which should be minimized. The constraints on the actuator forces and that of the obstacle-avoidance, together with sufficiently large weighting coefficients, are included in the augmented performance index. In the numerical implementation, the minimum-time motion is obtained for a planar 3-1ink manipulator amid several rectangular obstacles without simplifying any dynamic or geometric models.

• 대한기계학회논문집
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• 제18권11호
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• pp.2902-2912
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• 1994

The ultrasonic array sensor system, consisting of one transmitter and fourreceivers instead of the traditional combination of a transmitter and a receiver is proposed in order to identify the location of objects. From the theoretical analysis and the experimental results, it is found that this new array sensor system could derive the information on the position of objects accurately, while the traditional sensor system could provide only the informatioin on the distance to objects. This sensor system is used to develop a sonar-based local mapping algorithm. The local map is used to find the existence of possible gates, through which the mobile robots can pass, and to select the suitable one in order for the robots to reach the goal safely in the presence of obstacles. The performance of the proposed local map algorithm is demonstrated experimentally in a small working area with several obstacles. It is found that the quality of the resulting local map is sufficient for the avoidance of collisions between the robots and obstacles and for the selection of the suitable gate leading to the goal. It is also shown that the global map of the working area could be obtained by integrating several local maps constructed from different locations and that it matches the actual layout of the working area well.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.1939-1944
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• 2003

This paper presents a global path planning algorithm based on a visibility graph method, and applies additionally various constraints for constructing the reduced visibility graph. The modification algorithm for generating the rounded path is applied to the globally shortest path of the visibility graph using the robot size constraint in order to avoid the obstacle. In order to check the visibility in given 3D map data, 3D CAD data with VRML format is projected to the 2D plane of the mobile robot, and the projected map is converted into an image for easy map analysis. The image processing are applied to this grid map for extracting the obstacles and the free space. Generally, the tree size of visibility graph is proportional to the factorial of the number of the corner points. In order to reduce the tree size and search the shortest path efficiently, the various constraints are proposed. After short paths that crosses the corner points of obstacles lists up, the shortest path among these paths is selected and it is modified to the combination of the line path and the arc path for the mobile robot to avoid the obstacles and follow the rounded path in the environment. The proposed path planning algorithm is applied to the mobile robot LCAR-III.

• 제어로봇시스템학회논문지
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• 제13권7호
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• pp.631-636
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• 2007

An efficient obstacle avoidance algorithm is proposed in this paper to avoid dynamic obstacles using a collision vector while a tele-operated mobile robot is moving. For the verification of the algorithm, an operator watches through a monitor and controls the mobile robot with a force-reflection joystick. The force-reflection joystick transmits a virtual force to the operator through the Inter-net, which is generated by an adaptive impedance algorithm. To keep the mobile robot safe from collisions in an uncertain environment, the adaptive impedance algorithm generates the virtual force which changes the command of the operator by pushing the operator's hand to a direction to avoid the obstacle. In the conventional virtual force algorithm, the avoidance of moving obstacles was not solved since the operator cannot recognize the environment realistically by the limited communication bandwidth and the narrow view-angle of the camera. To achieve the dynamic obstacle avoidance, the adaptive virtual force algorithm is proposed based on the collision vector that is a normal vector from the obstacle to the mobile robot. To verify the effectiveness of the proposed algorithm, mobile robot navigation experiments with multiple moving obstacles have been performed, and the results are demonstrated.