• Aerospace Engineering and Technology
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• v.3 no.1
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• pp.242-250
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• 2004

This paper describes the detection method of wire-like obstacles using millimeter-wave radar system. Passive sensor like CCD camera can be used for the detection of high power electric cables on the hills or mountains and it can give very good quality of obstacle target information. But this system is very limited to use by bad weather condition. The detection capability for different diameters of wire targets using millimeter radar system have been accomplished. To simulate the target on the moving helicopter, rotating targets are used with fixed radar system. In the experiment 11mm, 16mm and 22mm diameter of wires have been detected in single, two and three wires in one position. The detected signal from single wire was very clear on gray level image. Three wires placed very closely together could be recognized in range, cross range image plane. For two and three wires, blur effect due to mutual scattering effect is observed.

• The Journal of Korea Robotics Society
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• v.1 no.1
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• pp.17-24
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• 2006

Though the final goal of mobile robot navigation is to be autonomous, operators' intelligent and skillful decisions are necessary when there are many scattered obstacles. There are several limitations even in the camera-based tele-operation of a mobile robot, which is very popular for the mobile robot navigation. For examples, shadowed and curved areas cannot be viewed using a narrow view-angle camera, especially in bad weather such as on snowy or rainy days. Therefore, it is necessary to have other sensory information for reliable tele-operations. In this paper, sixteen ultrasonic sensors are attached around a mobile robot in a ring pattern to measure the distances to obstacles. A collision vector is introduced in this paper as a new tool for obstacle avoidance, which is defined as a normal vector from an obstacle to the mobile robot. Based on this collision vector, a virtual reflection force is generated to avoid the obstacles and then the reflection force is transferred to an operator who is holding a joystick to control the mobile robot. Relying on the reflection force, the operator can control the mobile robot more smoothly and safely. For this bi-directional tele-operation, a master joystick system using a hall sensor was designed to resolve the existence of nonlinear sections, which are usual for a general joystick with two motors and potentiometers. Finally, the efficiency of a force reflection joystick is verified through the comparison of two vision-based tele-operation experiments, with and without force reflection.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.40 no.6
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• pp.515-522
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• 2012

CFIT(Controlled Flight Into Terrain) is one of the major causes of aircraft accidents. In order to solve this problem, GPWS(Ground Proximity Warning System) is used to generate terrain collision warning using the distance between the aircraft and the underneath ground. Since the GPWS uses the vertical clearance only, it frequently generates false warnings. In this study, a terrain/obstacle collision avoidance warning algorithm was developed for fast flying and highly maneuvering fighters using the flight status and the geographic information. This algorithm condsiders the overall delay in the aircraft reactive motion including the pilot's reaction time. The paper presents a detailed logic and test methods.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.47 no.2
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• pp.147-154
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• 2024

This study focuses on the path planning algorithm for large-scale autonomous delivery using drones and robots in urban environments. When generating delivery routes in urban environments, it is essential that avoid obstacles such as buildings, parking lots, or any other obstacles that could cause property damage. A commonly used method for obstacle avoidance is the grid-based A* algorithm. However, in large-scale urban environments, it is not feasible to set the resolution of the grid too high. If the grid cells are not sufficiently small during path planning, inefficient paths might be generated when avoiding obstacles, and smaller obstacles might be overlooked. To solve these issues, this study proposes a method that initially creates a low-resolution wide-area grid and then progressively reduces the grid cell size in areas containing registered obstacles to maintain real-time efficiency in generating paths. To implement this, obstacles in the operational area must first be registered on the map. When obstacle information is updated, the cells containing obstacles are processed as a primary subdivision, and cells closer to the obstacles are processed as a secondary subdivision. This approach is validated in a simulation environment and compared with the previous research according to the computing time and the path distance.

• Journal of Information Technology Services
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• v.13 no.1
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• pp.161-179
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• 2014

Added value of music industry in Korea is not distributed and calculated properly, and this obstacle brings various problems in a creative environment. Meanwhile, a new business model such as Open Collaboration, Crowdsourcing and platform that makes decisions and innovation from external resources has been appeared in commercial area. This new model like a composer delivers to consumers directly through Youtube.com, and multi collaboration is applied to the music industry, and it enables a new type of mechanism for creation, distribution, division, and calculation of music. However there are not enough empirical study of the music market because existing relative researches has been centered around fundamental concepts and application methodologies. This research defines Open Collaboration Platform in the music industry, and studies affecting factors of Participation Intention for example Justice, Information System Quality and Perceived Value. For a survey we apply PLS(Partial Least Square) to analyse Equity, Information System Quality and structural equation between Perceived Value and Participation Intention. Analysis results show Distributive Justice and Procedural Justice affects Platform Trust, and Service Quality, Economical Value and Emotional Value affects Platform Usefulness. Also Platform Trust and Platform Usefulness affects Platform Participation Intention. We discussed academic and practical implication based on research results.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.1921-1926
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• 2003

We build a local minimum free motion planning for mobile robots considering dynamic environments by simple sensor fusion assuming that there are unknown obstacles which can be detected only partially at a time by proximity sensors and can be cleaned up or moved slowly (dynamic environments). Potential field is used as a basic platform for the motion planning. To clear local minimum problem, the partial information on the obstacles should be memorized and integrated effectively. Sets of linked line segments (SLLS) are proposed as the integration method. Then robot's target point is replaced by virtual target considering the integrated sensing information. As for the main proximity sensors, we use laser slit emission and simple web camera since the system gives more continuous data information. Also, we use ultrasonic sensors as the auxiliary sensors for simple sensor fusion considering the advantages in that they give exact information about the presence of any obstacle within certain range. By using this sensor fusion, the dynamic environments can be dealt easily. The performance of our algorithm is validated via simulations and experiments.

• Journal of KIISE:Information Networking
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• v.35 no.3
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• pp.207-214
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• 2008

There are lots of studies on application systems using wireless sensor networks. As the application systems are adapted to industrial field, the reliability of these systems becomes new key feature. The lack of reliability is an obstacle to extension of wireless sensor networks. In this paper, we propose the monitoring system framework that can offer the reliability of wireless sensor networks using a micro camera module and wireless sensor network nodes. And also we propose the efficient transfer method for image information over low rate wireless networks. Using these system framework and transfer method, we implement WiSN(Wireless image Sensor Network) based fire monitoring system.

• Journal of Korean Library and Information Science Society
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• v.41 no.1
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• pp.77-98
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• 2010

Recently, small libraries have greatly increased by the support and interest of the central, or local government. Since 2004, 47 small libraries were established in Jeon-buk province. These libraries are equipping a new facility and collection with their support. Nevertheless, they still have many problems in operating process. This is causing degradation of the quality level of information service for local residents, further, this becomes the obstacle which solves a information divide and improves the cultural welfare. The purpose of this study is to analyze the status of small libraries in Jeon-buk province, and then, to propose solutions to problems.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.5 no.3
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• pp.399-403
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• 2001

The existent number system, which is divided into two, will give much obstacle to achieve Information and Communication exchange between south and north korea. Therefore as a long point of view, As the number system between two koreas have to meet the communication demand and the service development. It is very important to set up the most effective and suitable structure and system in given communication environment. To prepare the future its growth as the advent of new network and communication service, This paper presents the scheme of a number system unification which is essential in the unification of Information and communication between two countries after Korea-unification.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2001.05a
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• pp.579-582
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• 2001

The existent number system, which is divided into two, will give much obstacle to achieve Information and Communication exchange between south and north korea. Therefore as a long point of view, It is very important to set up the most effective and suitable structure and system in given communication environment as the number system between two koreas have to meet the communication demand and the service development. To prepare the communications growth for the future such as the advent of new network and communication service, This paper presents the scheme of a number system unification which is essential in the unification of information and communication between two countries after Korea-unification.