• The Journal of Korean Institute of Communications and Information Sciences
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• v.39C no.9
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• pp.811-819
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• 2014

Activity recognition is a key component in identifying the context of a user for providing services based on the application such as medical, entertainment and tactical scenarios. Instead of applying numerous sensor devices, as observed in many previous investigations, we are proposing the use of smartphone with its built-in multimodal sensors as an unobtrusive sensor device for recognition of six physical daily activities. As an improvement to previous works, accelerometer, gyroscope and magnetometer data are fused to recognize activities more reliably. The evaluation indicates that the IBK classifier using window size of 2s with 50% overlapping yields the highest accuracy (i.e., up to 99.33%). To achieve this peak accuracy, simple time-domain and frequency-domain features were extracted from raw sensor data of the smartphone.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.1
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• pp.109-113
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• 2011

Recently, according to the development of ubiquitous computing, the u-GIS which not only used in u-Transport, u-Care, u-Fun, u-Green, u-Business, u-Government, and u-City but also used to provides various spatial information such as the location of user is being the core technology of the ubiquitous computing environment. In this paper, we implemented an mobile spatio-temporal Query Processing Systems for handling the Spatio-Temporal Data in mobile equipment.The mobile spatio-temporal Query Processing Systems provides the spatio-temporal data type and the spatio-temporal operator that is expanded by the spatial data type and the spatial operator from OepenGIS "Simple Feature Specification for SQL". It supports arithmetic coding compression techniques that is considered with a spatio-temporal data specific character. It also provides the function of data cashing for improving the importation and exportation of the spatio-temporal data between a embedded spatio-temporal DBMS and u-GIS server.

• Journal of Digital Contents Society
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• v.6 no.4
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• pp.201-208
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• 2005

In high-technology digital age that change everyday fast, Web became most familiar and essential tool to public. Since creation of web, web began from the first step web that offer simple information and contents. and now, it have developed to step offer dynamic contents that various multimedia components are combined. In future, it will develop to the next generation, intelligence style Semantic Web that Meta Communication of meaning-base is possible. In this paper, we examine about concept and characteristic of Semantic web that is a point technology in next generation. Also, we studied about example and practical use in personalized contents side that is based on Semantic Meta-Communication system. Semantic web is value industry field that has infinite possibility and has necessary of a lot of studies and development yet. Therefore in digital age, we expect this paper will help for space construction of more mature communication.

• Current Industrial and Technological Trends in Aerospace
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• v.9 no.1
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• pp.119-129
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• 2011

The soft landing of a lunar lander after the entrance of lunar orbit is an essential prerequisite for the accomplishment of the lander's lunar mission. During the landing process of a lunar lander, efficient shock absorption and stability maintenance are indispensible technology to protect payloads. Therefore, the landing gear is a crucial structural component of a lunar lander, it has to absorb the kinetic energy associated with touchdown and support the static load of the landing module in an upright position. In this paper, various landing gears of lunar landers which are being developed as well as which had been successfully landed on the moon surface are investigated. In the end, the Korean lunar lander, which is being designed for preliminary development model, is presented as an example of the lunar lander development.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.21-25
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• 2017

The umbilical system used for launch vehicle is to connect all ground supply lines (Pneumatic, hydraulic and electrical) to launch vehicle and disconnect those at few second before launch vehicle lift-off (or simultaneously with launch vehicle lift-off). During launch preparation stage, all umbilical shall be securely connected and also at separation stage, separation of all umbilical line shall be guaranteed. Therefore finding an appropriate connection force is a key factor on development of umbilical system. According to these design requirement, various kind of umbilical system has been developed from early stage of space development till today. In this paper, various kind of umbilical system developed so far is introduced according to its feature and operational concept. Also, umbilical system used for KSLV-II is introduced

• Journal of Wetlands Research
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• v.21 no.4
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• pp.267-280
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• 2019

Adaptive Management (AM) is one of the best available approaches for managing natural resources in the presence of uncertainty. In spite of the limitations, AM has been widely applied in nature resource management policies and plans internationally, while application of AM in nature resource management in Korea is limitedly used. Accordingly, this study reviews application of AM in nature resource management research in Korea with respect to its definitions, procedures, impediments and considerations. The present study also reviews recent ecological modelling studies which is an essential component of AM approach. Finally, management of artificial sea forest, coastal wetlands and fisheries are suggested as the recommended fields to adopt AM.

• Journal of the Korea Convergence Society
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• v.9 no.3
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• pp.23-29
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• 2018

There is a growing interest in computer based learning system that can learn a new concept of epistemic frames in response to the demands of $21^{st}$ century Skills. However, there is little research on the theoretical models for the epistemic frames applicable in the changing educational environment and the measurement theories (Psychometric theory, Learning Analytics) that can be evaluated. Therefore, in this study, we propose the core elements of the learning system prototype that can educate the epistemic frames in the practical community. Furthermore, this study explores and suggests an appropriate psychometric measurement theory (learning analytics) that allows us to measure, infer, and evaluate a learner.

• Korean Journal of Construction Engineering and Management
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• v.14 no.3
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• pp.88-96
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• 2013

Recent proliferation of building information modeling (BIM) has actively stimulated integrated utilization of geometric (graphic) and non-geometric (non-graphic) data. Nevertheless, physically and logically, linking and maintaining these two different types of data in an integrated manner requires enormous overhead efforts for practical implementation. In order to address this problem, this paper proposes a concept and structure of the object breakdown structure (OBS) that facilitates advanced BIM implementations in an automated and effective manner. Proposed OBS numbering system has secure rules for organizing graphic objects in full considerations of effectively integrating with non-geometric data (e.g. cost and schedule). It also removes repetitive linking process caused by design changes or modifications. The result of applying this concept to a housing project revealed that only 120 definitions controled over 6,000 graphic objects for full integration with cost and schedule functions.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39C no.11
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• pp.1104-1113
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• 2014

Future combat systems can be represented as the NCW (Network Centric Warefare), which is based on the concept of Sensor-to-Shooter. A wireless video sensor networking technology, one of the core components of NCW, has been actively applied for the purpose of tactical surveillance. In such a surveillance sensor network, multi-composite sensors, especially consisting of image sensors are utilized to improve reliability for intrusion detection and enemy tracing. However, these sensors may cause a problem of requiring very high network capacity and energy consumption. In order to alleviate this problem, this paper proposes an image data transmission scheme based on resource reservation. The proposed scheme can make it possible to have more reliable image data transmission by choosing proper multiple interfaces, while trying to control resolution and compression quality of image data based on network resource availability. By the performance analysis using NS-3 simulation, we have confirmed the transmission reliability as well as energy efficiency of the proposed scheme.

• Journal of Korea Game Society
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• v.14 no.2
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• pp.67-76
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• 2014

Recently there have been many interests on tangible sport games that can recognize the motions of players. In this paper, we propose essential technologies required for tangible games, which are methods for swing motion recognition and the calculation of shuttle cock's trajectory. When a user carries out a badminton swing while holding a smartphone with his hand, the motion signal generated by smartphone-embedded acceleration sensors is transformed into a feature vector through a Daubechies filter, and then its swing type is recognized using a k-NN based method. The method for swing motion presented herein provides an advantage in a way that a player can enjoy tangible games without purchasing a commercial motion controller. Since a badminton shuttle cock has a particular flight trajectory due to the nature of its shape, it is not easy to calculate the trajectory of the shuttle cock using simple physics rules about force and velocity. In this paper, we propose a method for calculating the flight trajectory of a badminton shuttle cock in which the wind effect is considered.