• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2007년도 춘계학술대회 논문집
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• pp.85-88
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• 2007

A number of R, G and B LEDs for reference color temperature mixing ratio of RGB was determined by the theory of RGB mixing as a baseline. Once the number of LEDs was determined the objective color temperature from baseline has been achieved by the control the RGB duty ratio. And a practical prototype of 50W floodlighting adjusted by the above algorithm. The micro controller was developed with control algorithm for RGB duty ratio to obtain the objective color temperature. Detailed experiments to optimize algorithm of duty ratio and color temperature will be discussed in this paper as well.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2003년도 추계학술발표대회 논문집
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• pp.187-189
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• 2003

Almost all building/infrastructures made of composite materials are fabricated without proper design. Unlike airplane or automobile parts, prototype test is impossible. One cannot destroy 10 story buildings or 100-meter long bridges. People try to build 100-story buildings or several thousand meter long bridges. In order to realize "composites in construction", the following subjects must be studied in detail, for his design: Concept optimization, Simple method of analysis, Folded plate theory, Size effects in failure, and Critical frequency. Unlike the design procedure with conventional materials, his design should include material design, selection of manufacturing methods, and quality control methods, in addition to the fabrication method.on method.

• Journal of Ship and Ocean Technology
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• 제1권2호
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• pp.1-10
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• 1997

The prediction of the total resistance of a ship is generally based on considering it to be a simple sum of the viscous resistance and the wave resistance. An experimental approach for predicting full-size ship resistance on this basis is practical but obviously has the deficiency that a model has to be built for each prototype of interest and the resulting tank tests are time consuming. On the other hand, purely theoretical calculations of the wave resistance, using, for example, the Michell theory, require relatively little computer time and give an excellent portrayal of the overall variation of the vessel resistance as a function of forward speed. Unfortunately, there are sufficient differences between this theory and the measured results to make this method impractical for design purposes. The proposal examined here is to use a data bank of experimental resistance results to modify the theoretical predictions. It is demonstrated that the technique will produce remarkably accurate resistance predictions and can take into account the effects of the water depth, any restriction of canal or river width, as well as the prismatic coefficient, and other geometric parameters.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 추계학술대회 논문집
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• pp.865-871
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• 2007

The levitation system of Maglev is composed with electro-magnet, power supplier, controller and sensor. The complex interactions between above subcomponents define the characteristics of electromagnetic suspension of the vehicle. In this study, to understand the influence of controller on the running performance of Maglev, the new controller based on LQ theory will be designed and be simulated with simplified vehicle model. Then the influence of controller on the characteristics of electromagnetic suspension will be reviewed through comparison with existing control algorithm of our prototype vehicle.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2003년도 춘계학술발표대회 논문집
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• pp.161-164
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• 2003

Almost all buildings/infrastructures made of composite materials are fabricated without proper design. Unlike airplane or automobile parts, prototype test is impossible. One cannot destroy 10 story buildings or 100-meter long bridges. People try to build 100-story buildings or several thousand meter long bridges. In order to realize "composites in construction", the following subjects must be studied in detail, for his design: Concept optimization, Simple method of analysis, Folded plate theory, Size effects in failure, and Critical frequency. Unlike the design procedure with conventional materials, his design should include material design, selection of manufacturing methods, and quality control methods, in addition to the fabrication method.on method.

• 디지털산업정보학회논문지
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• 제6권2호
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• pp.169-182
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• 2010

The purpose of the study is to prospect the application of knowledge awareness system in the use of the digital textbook which is one of the main educational political projects based on the exploration of the awareness theory for the computer-supported collaborative learning. To do this, first, knowledge awareness theory for computer-supported collaborative learning (CSCL) as a rationale for digital textbook which supports the collaborative learning was introduced. Second, three functionalities of knowledge awareness systems were extracted by analyzing the representative knowledge awareness tools of CSCL environment. Third, application prospects of knowledge awareness system toward the development and utilization of digital textbook were presented. The paper suggested the need of more researches such as the prototype development of digital textbook which applies the knowledge awareness system's functionalities and empirical researches which examine their effectiveness and efficiency.

• 대한수학교육학회지:수학교육학연구
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• 제12권4호
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• pp.523-542
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• 2002

The matter of understanding mathematical concepts in learning mathematics is one of the most important issues in mathematics education. There have been so many studies about it but the more practical study has been asked. When we Think using intuitional models such as examples, figures of speech, situations and activities, it is supposed that the major elements of cognitive mechanism are prototypes, analogies, metaphors and metonymies. In this paper, we tried to examine Rosch's prototype theory, the studies about analogies in congnitive psychology, Lakoff and Johnson's metaphor theory from the viewpoint of teaching mathematics, and then tried to analyze examples, analogies, analogical transfers, metaphorical expressions, metonymies in middle school mathematics text books used in Korea now.

• Journal of Power Electronics
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• 제13권6호
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• pp.919-927
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• 2013

This paper proposes a Boundary Current Mode (BCM) control scheme to realize soft switching on a conventional single phase full bridge DC/AC inverter. This technique with the advantages of no auxiliary components, low cost, high efficiency, and simple in control, is attractive for micro-inverter applications. The operation principle and characteristic waveforms of the proposed soft switching technique are analyzed in theory. A digital controller is provided based on that theory. To balance the requirements of efficiency, switching frequency, and inductor size, the design considerations are discussed in detail to guide in BCM inverter construction. A 150W prototype is built under these guidelines to implement the BCM control scheme. Simulation and experiment results demonstrate the feasibilities of the proposed soft switching technique.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2003년도 Proceedings of ACRS 2003 ISRS
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• pp.307-309
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• 2003

The paper compares Static GIS, Mobile GIS, Dynamic GIS and Moving GIS at first, then puts forward and discusses a description means of mobile objects, a model of spatial relation based on 9-intersection model and the query and analysis operations that Moving GIS should implement. On the above theory basis, the paper designs the function of Moving GIS and implements a prototype system named PNS-I on the basis of PDA, which has integrated GPS, GIS, GSM and GPRS.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2006년도 학술발표회 논문집
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• pp.89-96
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• 2006

Recently, many researches on the dissipation of excess pore pressure in liquefied sand grounds have been performed to evaluate post-liquefaction behaviors of structures. In this paper. centrifuge tests were performed to simulate liquefaction behaviors of prototype soil. The evaluation model of solidified layer thickness was developed to simulate non-linear variation of solidified layer thickness with time. Also, the dissipation of excess pore pressure in liquefied sand was evaluated by applying the solidification theory and the consolidation theory. The developed model gives a good estimation of the solidified layer thickness and the time history of excess pore pressure.