• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.250-255
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• 2005

For navigation of a service robot, mapping and localization are very important. To estimate the robot pose, the map of the environment is required and it can be built by exploration or SLAM. Exploration is the fundamental task of guiding a robot autonomously during mapping such that it covers the entire environment with its sensors. In this paper, an efficient exploration scheme based on the position probability of the end nodes of a topological map is proposed. In this scheme, a topological map is constructed in real time using the thinning-based approach. The robot then updates the position probability of each end node maintaining its position at the current location based on the Bayesian update rule using the range data. From this probability, the robot can determine whether or not it needs to visit the specific end node to examine the environment around this node. Various experiments show that the proposed exploration scheme can perform exploration more efficiently than other schemes in that, in most cases, exploration for the entire environment can be completed without directly visiting everywhere in the environment.

• Journal of Environmental Science International
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• v.19 no.3
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• pp.343-351
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• 2010

Since the effect of environmental education at class using textbooks or materials related to environment is limited, the importance of activities for field experience is getting increased day by day. Thereby, the education tends to change into the type of education providing students with direct environmental experience. Students attending the science high school have excellent aptitude and ability for science and will lead the development of science in the future. Now it is urgent to develop various experiential programs which are helpful for them to establish desirable values on environment. However, the field of environmental education that allows science high school students equipped with ample environmental knowledge to improve environment sensitivity and have proper environment awareness is quite restricted as of now. Natural exploration activities are the programs which provide science high school students having lack of chance for environmental education with good opportunities to contact nature and also play significant roles in arousing their interest in issues related with environment. Therefore, it is thought that they will let science high school students explore the natural features of Korea, understand the importance of preserving environment and ecosystem profoundly, and encourage environmental awareness and will of environmental practice. Thereupon, with the study subjects of 121 first and second graders at U Science High School, this article analyzed their recognition of the necessity for environmental education and environmental pollution problems before and after the natural exploration activities, and conducted a survey on their satisfaction after the natural exploration activities and analyzed it. The result of this research is as follows. First, it was shown that the natural exploration activities were effective to raise the science high school students' awareness of issues related with environmental pollution. Second, the natural exploration activities had effect upon enhancing the students' willingness of environmental practice. Third, there was statistically significant correlation between the science high school students' satisfaction with the natural exploration activities and their achievement in the science subject. Fourth, there also was a statistically non or weakness significant correlation between their satisfaction with the natural exploration activities and preference for the science subject. In particular, it was found that students preferring biology indicated higher satisfaction.

• Journal of Korea Game Society
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• v.15 no.1
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• pp.115-124
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• 2015

This research analyzed the case of Ncsoft to study the organizational learning, exploitation and exploration that create dynamic capability in hypercompetitive environment. First of all, we demonstrated the activities of exploitation and exploration in Ncsoft according to the life cycle of online game industry. An exploitation related to routine, learning and fit with existing environment brings about incremental innovation. In contrast, an exploration associated with non-learning, flexibility with changing environment results in radical innovation. We examined them based on the life cycle of its various game services. NCsoft that built the leading position in online game industry focused the exploitation activities at the stage of beginning period and growth, whereas NCsoft has increased the activities of exploration at period of mature. In addition, the firm conducts an exploration for its brand new game services and R&D. Conversely, An exploitation is conducted for sustainable updating of patch service and marketing and system building. The result implies that online game companies create sustainable competitive advantage using the balance between exploitation and exploration.

• The Bulletin of The Korean Astronomical Society
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• v.36 no.2
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• pp.93.2-93.2
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• 2011

Japan Aerospace Exploration Agency (JAXA) has measured space environment and its effects on spacecraft and astronaut since 1987. At present, we have operated space environment monitors onboard one GEO spacecraft, one QZO spacecraft, and two LEO spacecrafts. The obtained space environment data has been gathered into the Space Environment and Effects System database (SEES, http://sees.tksc.jaxa.jp/). In this presentation, measurement result of space environment in low earth orbit obtained by the Daichi satellite from 2006 through 2011 is reported as well as recent activities in space environment engineerings in JAXA. The Technical Data Acquisition Equipment (TEDA) on board the Daichi satellite (Advanced Land Observing Satellite: ALOS) had been operated in low earth orbit at 700 km altitude with 98 degree inclination from February 2006 until April 2011. The TEDA consists of the Light Particle Telescope and the Heavy Ion Telescope. The operation period of the Daichi satellite was through the solar-activity minimum period. The space radiation environment around the Daichi satellite had been almost stable. However, large solar flares followed by CMEs sometimes disturbed the space radiation environment in the orbit of the Daichi satellite. In addition, high speed solar wind often flowed and modulated the electron flux in the horn region. On the other hand, a little variation was seen in the SAA region.

• The Journal of Korea Robotics Society
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• v.18 no.4
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• pp.487-495
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• 2023

This paper presents a method for autonomous exploration of indoor environments using a 2-dimensional Light Detection And Ranging (LiDAR) scanner. The proposed frontier-based exploration method considers navigability from the current robot position to extracted frontier targets. An approach to constructing the point cloud grid map that accurately reflects the occupancy probability of glass obstacles is proposed, enabling identification of safe frontier grids on the safety grid map calculated from the point cloud grid map. Navigability, indicating whether the robot can successfully navigate to each frontier target, is calculated by applying the skeletonization-informed rapidly exploring random tree algorithm to the safety grid map. While conventional exploration approaches have focused on frontier detection and target position/direction decision, the proposed method discusses a safe navigation approach for the overall exploration process until the completion of mapping. Real-world experiments have been conducted to verify that the proposed method leads the robot to avoid glass obstacles and safely navigate the entire environment, constructing the point cloud map and calculating the navigability with low computing time deviation.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.16 no.10
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• pp.3373-3389
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• 2022

Exploration of mobile robot without prior data about environments is a fundamental problem during the SLAM processes. In this work, we propose improved version of previous Rmap algorithm by modifying its Exploration submodule. Despite the previous Rmap's performance which significantly reduces the overhead of the grid map, its exploration module costs a lot because of its rectangle following algorithm. To prevent that, we propose a new Rmap+ algorithm for autonomous path planning of mobile robot to explore an unknown environment. The algorithm bases on paired frontiers. To navigate and extend an exploration area of mobile robot, the Rmap+ utilizes the inner and outer frontiers. In each exploration round, the mobile robot using the sensor range determines the frontiers. Then robot periodically changes the range of sensor and generates inner pairs of frontiers. After calculating the length of each frontiers' and its corresponding pairs, the Rmap+ selects the goal point to navigate the robot. The experimental results represent efficiency and applicability on exploration time and distance, i.e., to complete the whole exploration, the path distance decreased from 15% to 69%, as well as the robot decreased the time consumption from 12% to 86% than previous algorithms.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.03a
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• pp.628-637
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• 2008

The JAXA's TechCLEAN project(2003-present) is summarized, with the interim technical achievements. TechCLEAN is collateral program with the NEDO engine project to accelerate R&D work of small passenger aircraft engine as well as to develop innovative environment technologies applicable to the future improvements. In the project NOx reduction, CO2 reduction and noise reduction are targeted. Component level researches and system demonstrator validation are planned with test facility renovation and demonstration base engines.

• 한국지구물리탐사학회:학술대회논문집
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• 2001.09a
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• pp.14-22
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• 2001

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.9 no.2
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• pp.45-50
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• 2009

The environment exploration is an essential process for indoor robots such as clean robot and security robot. Apartment house and office building has common frame structure, but internal arrangement of each room may be slightly different. So, it is more convenient to use a common frame map than to build a new map at every time the arrangement is changed. In this case, it is important to recognize invariant features such as wall, door and window. In this paper, an indoor mobile robot is implemented, and by using the laser scanner data and line segment histogram with respect to segment orientation and distance, an environment exploration method is presented and tested. This robot is fitted with a laser scanner, gyro sensor, ultra sonic sensor and IR sensor, and programed with C language.

• The Journal of Korea Robotics Society
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• v.8 no.4
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• pp.256-265
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• 2013

A local map-based exploration algorithm for mobile robots is presented. Segmented frontiers and their relative transformations constitute a tree structure. By the proposed efficient frontier segmentation and a local map management method, a robot can reduce the unknown area and update the local grid map which is assigned to each frontier node. Although this local map-based exploration method uses only local maps and their adjacent node information, mapping completion and efficiency can be greatly improved by merging and updating the frontier nodes. Also, we suggest appropriate graph search exploration methods for corridor and hall environments. The simulation demonstrates that the entire environment can be represented by well-distributed frontier nodes.