이 연구의 목적은 자극의 이동속도와 이동거리가 패서의 기술수준별로 정확한 패스 동작을 수행하는데 필요한 동작계획시간과 동작실행시간, 그리고 패스의 타이밍 정확성에 어떠한 영향을 미치는지 알아보는 데 있다. 이를 위해 초보자 15명과 숙련자 15명의 대상에게 불빛 자극의 이동속도(1.5m/s, 3.0m/s, 4.5m/s)와 이동거리(2m, 4m)가 다른 과제 상황에서 불빛 자극이 목표지점에 도달하는 시점과 일치되게 패스를 수행하도록 하였다. 실험과제는 각 조건 당 5회씩 총 30회가 무선으로 제시되었으며, 매 시행마다 추정반응시간, 동작시간, 그리고 타이밍의 정확성을 측정하였다. 그 결과, 초보자와 숙련자 모두 자극의 이동속도가 동일한 조건에서는 이동거리가 길어질수록 추정반응시간과 동작시간도 길어지는 것으로 나타났다. 단, 숙련자의 경우, 자극이 느린 속도로 이동할 때에는 자극이동거리 간 동작시간의 차이는 나타나지 않았다. 절대오차는 느린 속도로 이동한 경우를 제외하고는 중간조건과 빠른 조건 모두 자극의 이동거리가 길어질수록 타이밍 정확성은 높아졌다. 또한 초보자와 숙련자 모두 자극이동거리가 길수록 패스의 타이밍 정확성은 높은 것으로 나타났다.

Low-cost sensors have been widely used for mobile robot navigation in recent years. However, navigation performance based on low-cost sensors is not good enough to be practically used. Among many navigation techniques, building of an accurate map is a fundamental task for service robots, and mapping with low-cost IR sensors was investigated in this research. The robot’s orientation uncertainty was considered for mapping by modifying the Bayesian update formula. Then, the data association scheme was investigated to improve the quality of a built map when the robot’s pose uncertainty was large. Six low-cost IR sensors mounted on the robot could not give rich data enough to align the range data by the scan matching method, so a new sample-based method was proposed for data association. The real experiments indicated that the mapping method proposed in this research was able to generate a useful map for navigation.

This study was conducted to assess water movement in paddy-upland rotation soil scheduled for ginseng cultivation through the measurement of infiltration and permeability of soil water. Soil sample was divided with four soil layers. The first soil layer (to 30cm from top soil) was loamy sand, the second and the third soil layers (30~70 ㎝) were sand, and the fourth (〈 120 ㎝) was sandy loam. The soil below 130 ㎝ of fourth soil layer was submerged under water. The shear strength, which represents the resisting power of soil against external force, was 3.1 kPa in the first soil layer. This corresponded to 1/8 of those of another soil layer and this value could result in soil erosion by small amount of rainfall. The rates of infiltration and permeability depending on soil layers were 39.86 cm hr-1 in top soil, 2.34 cm hr-1 in 30~70 ㎝ soil layer, 5.23 cm hr-1 and 0.18 cm hr-1 in 70~120 ㎝ soil layer, with drain tile, and without drain tile, respectively. We consider that ground water pooled in paddy soil and artificial formation of soil layer could interrupt water canal within soil and affect negatively on water movement. Therefore, we suggest that to drain at 5 m intervals be preferable when it makes soil dressing or soil accumulation to cultivate ginseng in paddy-upland rotation soil to reduce failure risk of ginseng cultivation.

본 연구는 경사표면의 특성과 경사각도에 따라 아동과 성인의 자세유지 및 보행 관련 어포던스 지각에 차이가 있는지를 알아보고, 수행 가능성에 대한 지각과 실제 수행 결과간의 관계가 연령에 따라서 어떻게 다른지를 살펴보고자 하였다. 이를 위하여 취학 전 아동(M=5.7세), 취학 후 아동(M=9.8세), 성인(M=24.2세) 집단별로 각각 12명씩의 연구 대상자가 참여하였다. 실험 과제는 거친 표면과 미끄러운 표면으로 이루어지고 일곱 가지의 경사각도(12°, 17°, 22°, 27°, 33°, 39°, 45°)를 갖는 경사면에서 직립자세를 유지하고 걸어 올라갈 수 있는 가능성을 판단하는 과제와 실제로 경사면 위에서 직립자세와 이동 과제를 수행하는 것이었다. 연구 결과, 취학 전 아동은 경사각도가 심한 경사면에서 취학 후 아동과 성인에 비하여 자신의 능력을 과대평가하는 성향이 두드러지게 나타났다. 이러한 성향은 직립자세유지와 이동 과제에서 모두 동일하게 나타났다. 흥미로운 것은 이러한 지각 판단과 실제 수행간의 차이가 27°와 33°의 경사에서 경사표면의 특성에 따라 다르게 나타나, 미끄러운 표면에서는 과대평가 성향이, 거친 표면에서는 과소평가 성향이 크게 나타났다는 점이다. 언어적 반응 시간 결과에서는 모든 대상자들이 33°의 경사에서 지각 판단에 소요된 시간이 가장 많이 걸린 것으로 나타났으며, 취학 전 아동이 취학 후 아동과 성인에 비하여 직립자세를 유지하는 자신의 능력에 대한 지각 판단에 어려움이 큰 것으로 나타났다. 결론적으로, 연령과 환경적 특성에 따라 직립자세유지와 이동과 관련된 어포던스 지각이 다르게 나타난다는 사실은 지각-동작 연합 발달 측면에서 중요하며, 이는 어린 아동의 안전사고를 예방할 수 있는 환경을 조성하는 데 중요한 정보를 제공해 줄 수 있을 것이다.

This paper presents a goal-directed reactive obstacle avoidance method based on lane method. The reactive collision avoidance is necessarily required for a robot to navigate autonomously in dynamic environments. Many methods are suggested to implement this concept and one of them is the lane method. The lane method divides the environment into lanes and then chooses the best lane to follow. The proposed method does not use the discrete lane but chooses a line closest to the original target line without collision when an obstacle is detected, thus it has a merit in the aspect of running time and it is more proper for narrow corridor environment. If an obstacle disturbs the movement of a robot by blocking a target path, a robot generates a temporary target line, which is parallel to an original target line and tangential to an obstacle circle, to avoid a collision with an obstacle and changes to and follows that line until an obstacle is removed. After an obstacle is clear, a robot returns to an original target line and proceeds to the goal point. Obstacle is recognized by laser range finder sensor and represented by a circle. Our method has been implemented and tested in a corridor environment and experimental results show that our method can work reliably.

하천은 지역마다 독특한 하도특성을 지니고 있다. 우리나라는 전 국토의 70 %가 산지로 구성되어 있으며, 이 가운데 노년기에 지형도 적지 않다. 이를 가로 지르는 우리나라 하천에서 특이한 하도형태의 모습을 보이는 구간이 곳곳에 산재하고 있다. 그 대표적인 모습이 충적하도와 침식하도가 연속해 발생하는 과정에서 나타나는 하천 협소부이다. 하천 협소부란 하천지형학에서 일반적으로 쓰이고 있는 용어이며, 하도수리학에서는 지배유량에 종속되는 일정하폭의 범위를 크게

This paper presents a remote monitoring and simulation system for a building cleaning mobile robot. It provides a tool of convenient 3D graphical map construction including network camera image viewer and status information of the robot. The 3D map is reconstructed from existing 2D building CAD data with DXF format using OpenGL graphic API. Through this system, it is possible to monitor and control the cleaning mobile robot from remote place. A practical experiment is performed to show the reliability and convenience of the monitoring system. The proposed system is expected to give efficient the way of control and monitoring to building cleaning mobile robot.

One of the main problems of topological localization in a real indoor environment is variations in the environment caused by dynamic objects and changes in illumination. Another problem arises from the sense of topological localization itself. Thus, a robot must be able to recognize observations at slightly different positions and angles within a certain topological location as identical in terms of topological localization. In this paper, a possible solution to these problems is addressed in the domain of global topological localization for mobile robots, in which environments are represented by their visual appearance. Our approach is formulated on the basis of a probabilistic model called the Bayes filter. Here, marginalization of dynamics in the environment, marginalization of viewpoint changes in a topological location, and fusion of multiple visual features are employed to measure observations reliably, and action-based view transition model and action-associated topological map are used to predict the next state. We performed experiments to demonstrate the validity of our proposed approach among several standard approaches in the field of topological localization. The results clearly demonstrated the value of our approach.

Recently, simultaneous localization and mapping (SLAM) approaches employing Rao-Blackwellized particle filter (RBPF) have shown good results. However, no research is conducted to analyze the result representation of SLAM using RBPF (RBPF-SLAM) when particle diversity is preserved. After finishing the particle filtering, the results such as a map and a path are stored in the separate particles. Thus, we propose several result representations and provide the analysis of the representations. For the analysis, estimation errors and their variances, and consistency of RBPF-SLAM are dealt in this study. According to the simulation results, combining data of each particle provides the better result with high probability than using just data of a particle such as the highest weighted particle representation.

최근 컨테이너터미널 간의 경쟁이 심화되면서 생산성 측면뿐 만 아니라 비용경제성 측면에도 관심이 부각되고 있다. 특히, 에너지 소모량 및 장비투입 규모가 큰 트랜스퍼 크레인 부문에 대한 비효율적인 작업요소가 컨테이너터미널 경쟁력 제고에 있어서 걸림돌이 되고 있으며 이에 대한 개선은 인적, 물적 운영비용의 절감과 함께 생산성의 향상에도 긍정적인 영향을 미칠 것으로 기대된다. 따라서 본 연구에서는 현재 국토해양부 주관으로 진행 중인 'RFID를 활용한 RTLS 기반 항만물류효율화 사업'을 통하여 제공 가능한 컨테이너터미널 반 출입 대상 컨테이너의 시간적 가시성을 토대의 트랜스퍼 크레인의 배정 및 이동경로에 대한 클러스터링 기반 최적화모델을 제안하고 시뮬레이션 기법을 통하여 기대효과수준을 확인하였다.

Collision avoidance is a fundamental and important task of an autonomous mobile robot for safe navigation in real environments with high uncertainty. Obstacles are classified into static and dynamic obstacles. It is difficult to avoid dynamic obstacles because the positions of dynamic obstacles are likely to change at any time. This paper proposes a scheme for vision-based avoidance of dynamic obstacles. This approach extracts object candidates that can be considered moving objects based on the labeling algorithm using depth information. Then it detects moving objects among object candidates using motion vectors. In case the motion vectors are not extracted, it can still detect the moving objects stably through their color information. A robot avoids the dynamic obstacle using the dynamic window approach (DWA) with the object path estimated from the information of the detected obstacles. The DWA is a well known technique for reactive collision avoidance. This paper also proposes an algorithm which autonomously registers the obstacle color. Therefore, a robot can navigate more safely and efficiently with the proposed scheme.

This paper describes a new method for indoor environment mapping and localization with stereo camera. For environmental modeling, we directly use the depth and color information in image pixels as visual features. Furthermore, only the depth and color information at horizontal centerline in image is used, where optical axis passes through. The usefulness of this method is that we can easily build a measure between modeling and sensing data only on the horizontal centerline. That is because vertical working volume between model and sensing data can be changed according to robot motion. Therefore, we can build a map about indoor environment as compact and efficient representation. Also, based on such nodes and sensing data, we suggest a method for estimating mobile robot positioning with random sampling stochastic algorithm. With basic real experiments, we show that the proposed method can be an effective visual navigation algorithm.

We present the initial results of on-going research for building a novel Mobile Haptic Interface (MHI) that can provide an unlimited haptic workspace in large immersive virtual environments. When a user explores a large virtual environment, the MHI can sense the position and orientation of the user, place itself to an appropriate configuration, and deliver force feedback, thereby enabling a virtually limitless workspace. Our MHI (PoMHI v0.5) features with omnidirectional mobility, a collision-free motion planning algorithm, and force feedback for general environment models. We also provide experimental results that show the fidelity of our mobile haptic interface.

This paper describes the recognition method of moving objects in mobile robot with an omnidirectional camera. The moving object is detected using the specific pattern of an optical flow in omnidirectional image. This paper consists of two parts. In the first part, the pattern of an optical flow is investigated in omnidirectional image. The optical flow in omnidirectional image is influenced on the geometry characteristic of an omnidirectional camera. The pattern of an optical flow is theoretically and experimentally investigated. In the second part, the detection of moving objects is presented from the estimated optical flow. The moving object is extracted through the relative evaluation of optical flows which is derived from the pattern of optical flow. In particular, Focus-Of-Expansion (FOE) and Focus-Of-Contraction (FOC) vectors are defined from the estimated optical flow. They are used as reference vectors for the relative evaluation of optical flows. The proposed algorithm is performed in four motions of a mobile robot such as straight forward, left turn, right turn and rotation. Experimental results using real movie show the effectiveness of the proposed method.