• Journal of the Society of Naval Architects of Korea
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• v.58 no.2
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• pp.121-128
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• 2021

According to the increasing interest and demand for the Autonomous Surface Vessels (ASV), the autonomous navigation system is being developed such as obstacle detection, avoidance, and path planning. In general, autonomous navigation algorithm controls the ship by detecting the obstacles with various sensors and planning path for collision avoidance. This study aims to construct and prove autonomous algorithm with integrated various sensor using the Robot Operating System (ROS). In this study, the safety zone technique was used to avoid obstacles. The safety zone was selected by an algorithm to determine an obstacle-free area using 2D LiDAR. Then, drift angle of the ship was controlled by the propulsion difference of the port and starboard side that based on PID control. The algorithm performance was verified by participating in the 2020 Korea Autonomous BOAT (KABOAT).

• Journal of the Korean housing association
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• v.8 no.2
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• pp.113-122
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• 1997

This study analyzes behavior characteristics of illegal urban stall keepers scattered in the metropolitan area and their effects to urban life. The main findings of this study are follows. First, the stall keepers are different in terms of 1) items 2) opening hour and 3) user characteristics depending on locational environment of market boundaries. Second, the stall keepers exit in any time and any place if demand exists. Third, the effects of stall keepers to urban life are twofold ; they facilitate urban life by providing cheap and various commodities/services and they bring about negative effects such as obstacle to traffic flows, waste generation, and so on.

• Journal of Korea Society of Digital Industry and Information Management
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• v.11 no.3
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• pp.145-158
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• 2015

Disposable marine product packaging materials such as wooden, Styrofoam, and corrugated cardboard boxes have a very low reuse rate, thus causing the logistics costs to rise and making it difficult to establish a unit load system for marine products. Disposable packing containers to be discarded are accompanied by resource and environmental issues home and abroad. Transportation vehicles for marine products have to return empty without loading different kinds of products after delivery due to the smell and properties of marine products, thus posing as an obstacle to logistics rationalization. In an effort to overcome those limitations, this study examined the stages of transportation including "producer-wholesale market in the producing area-commission merchant-wholesale market in the consumption area-commission merchant-quasi-wholesale market-consumer" and also analyzed the utilization and distribution of disposable packaging materials currently used in the circulation of marine products including wooden, Styrofoam, and corrugated cardboard boxes. Based on the analysis results, the investigator developed a logistics rationalization model capable of promoting semi-permanent reuse and lowering empty vehicle rate on return routes as an alternative to address environmental issues caused by disposable packaging materials, which have been an obstacle to the logistics rationalization of marine products, packaging costs in the process of repeating packing and unpacking at each stage of marine products circulation, and empty vehicle rates on return routes after marine products delivery.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.31 no.3
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• pp.71-78
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• 2023

To minimize the occurrence of aviation accidents in the post-COVID, continuous flight training is crucial. However, the current infrastructure of domestic airports and airfields is insufficient to prepare for and respond to accidents, and there is a need for sufficient facility capacity. Therefore, this study examines the construction of a regional airport to minimize aviation accidents and selects factors necessary for determining the site location. Among the 11 selected factors, six were considered the most important site selection factors, including noise issues, weather conditions, obstacle limitations, environmental issues, airspace conditions, and facility usability. Applying these factors, an analysis was conducted on the Songpo area of Sacheon City, Gyeongsangnam-do. Based on a comprehensive review, it can be concluded that the Songpo area is a suitable choice for a regional airport due to its excellent transportation environment, consideration of noise and environmental issues with the residential population, and other factors. Furthermore, the development of the aviation industry is expected to bring about an increase in tourism and economic benefits, and it is anticipated to make a significant contribution to the domestic aviation industry along with the construction of the currently under-construction Ulleung Airport.

• Journal of Institute of Control, Robotics and Systems
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• v.7 no.1
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• pp.1187-1195
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• 2001

This paper presents a sweeping path planning algorithm for an autonomous smearing robot. An automatic planner generates a sweeping path pattern by proposed five basic procedures. This algorithm rocog-nizes obstacle on the architectural CAD draft and generates subgoals as tracking points which executes the area filling task based on heuristic approach. A sweeping path is planned by sequentially connecting the track-ing points in such a way that(1) the connected line segments should not be crossed, (2) the total tracking points should be as short as possible, and (3) the tracking line should not pass through the obstacle, Feasibility of the developed techniques has been demonstrated on a real architectural CAD draft.

• Journal of Institute of Control, Robotics and Systems
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• v.21 no.2
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• pp.115-120
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• 2015

Recently, in automotive technology area, intelligent safety systems have been actively accomplished for drivers, passengers, and pedestrians. Also, many researches are focused on development of autonomous vehicles. This paper propose the application of LiDAR sensors, which takes major role in perceiving environment, terrain classification, obstacle data clustering method, and local map building for autonomous driving. Finally, based on these results, planning for lane change path that vehicle tracking possible were created and the reliability of path generation were experimented.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2003.09a
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• pp.531-534
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• 2003

In this paper, the Intelligent Space (iSpace) concept is applied for helping disabled or blind persons in crowded environments such as train stations, or airports. The main contribution of this paper is a general mathematical (fuzzy-neuro) description of obstacle avoidance method (walking habit) of moving objects (human beings) in a limited area scanned by the iSpace. A mobile robot with extended functions is introduced as a Mobile Assistant Robot which is assisted by the iSpace. The Mobile Assistant Robot (MAR) can guide and protect a blind person in a crowded environment with the help of the Intelligent Space. The prototype of the Mobile Assistant Robot and simulations of some basic types of obstacle avoidance method (walking habit) are presented.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.7 no.4
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• pp.28-34
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• 1998

This paper presents a new method for local obstacle avoidance of indoor mobile robots. The method combines a directional approach called the lane method and a velocity space approach. The lane method divides working area into lanes and then chooses the best lane to follow for efficient and collision-free movement. Then, the heading direction to enter and follow the best lane is decided, and translational and rotational velocity considering physical limitations of a mobile robot are determined. Since this method combines both the directional and velocity space method, it shows collision-free motion as well as smooth motion taking the dynamic of the robot into account.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.1112-1117
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• 2010

The intelligent safety system for level crossing which employs information and communication technology has been developed in USA and Japan, etc. But, in Korea, the relevant research has not been performed. In this paper, we analyze the cause of railway level crossing accidents and the inherent problem of the existing safety equipments. Based on analyzed results, we design the intelligent safety system which prevent collision between a train and a vehicle. This system displays train approaching information in real-time at roadside warning devices, informs approaching train of the detected obstacle in crossing areas, and is interconnected with traffic signal to empty the crossing area before train comes. Especially, we present the video based obstacle detection algorithm and verify its performance with prototype H/W since the abrupt obstacles in crossing areas are the main cause of level crossing accidents. We identify that the presented scheme detects both pedestrian and vehicle with good performance. Currently, we demonstrate developed railway crossing intelligence system at one crossing of Young-dong-seon line of Korail with Sea Train cockpit.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.05a
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• pp.49-50
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• 2013

In wireless environment, to provide more efficient service area is need to maintain proper location of wireless LAN AP. Since structural effect corresponding to location of arbitrary scatterers must be considered. Using FDTD method, an obstacle in scattering field should be considered and its diffraction effect for some cross wall is estimated between transmitter and receiver point.