• Proceedings of the Korea Inteligent Information System Society Conference
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• 2007.05a
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• pp.111-120
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• 2007

Recently the importance of website becomes confident in realizing the long distance education (teleeducation) as web. The purpose of this research is evaluating the websites of cyber university and analyzes web usability and web accessibility and analyzes to suggest the good quality content and several personalized service. Also we tried to improve website quality and contribute the reliability of the long distance education with all these. For these we applied the of professor Hyung Nam Moon's SM-ABCDE website evaluation model and developed the check list suitable for cyber university and evaluated websites in the five views of Attraction, Business, Content, Design, Engineering. Totally Kyunghee Cyber University, Busan Digital University, Hanyang Cyber University is selected best in sequence. But every website doesn't keep the basic observation rule of the web accessibility.

• Proceedings of the KIPE Conference
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• 2000.07a
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• pp.127-132
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• 2000

This paper describes a 3-phase Line-Interactive APF system and analyzes its operating characteristics considering LC Filter output characteristics. Topology of APF is similar to that of Off-Line UPS in the point of parallelly operating inverter system. So it is possible to be multi-functioned active compensating system according to power condition. Likewise this actively operating system from APF to UPS and vice versa is often to be called Line-Interactive system. And more than that Line-Interactive system needs precise design of LC filter on converter output side to make this system fully operate in both APF and UPS modes. The problem in this point is how to design LC Filter to be contented with two different system characteristics so this paper analyzes this problem and proposes its design procedures. Then suggested filter design is verified to be contented by the simulations and experimental results

• Journal of Information Processing Systems
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• v.14 no.2
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• pp.523-538
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• 2018

Keystroke dynamics user authentication is a behavior-based authentication method which analyzes patterns in how a user enters passwords and PINs to authenticate the user. Even if a password or PIN is revealed to another user, it analyzes the input pattern to authenticate the user; hence, it can compensate for the drawbacks of knowledge-based (what you know) authentication. However, users' input patterns are not always fixed, and each user's touch method is different. Therefore, there are limitations to extracting the same features for all users to create a user's pattern and perform authentication. In this study, we perform experiments to examine the changes in user authentication performance when using feature vectors customized for each user versus using all features. User customized features show a mean improvement of over 6% in error equal rate, as compared to when all features are used.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.672_673
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• 2009

In this paper seeks the parameter which relates with the efficiency from premium efficiency level single-phase induction motor. Also it compares with the parameters and it analyzes and an optimum parameter it seeks by FEM. Consquently, a optimal design is accomplished from the this paper. Also parameters compare efficiency. And it analyzes and studies about optimum parameter by FEM. The sample single-phase induction motor selection selected existing premium level motor. We analyze each parameter using 2-D finite element analysis (FEM). According to Study of losses and Design flow, losses and efficiency can be explain by many parameter. So this paper present optimal parameters. Finally, this paper presents the method which raises the efficiency of premium efficiency level single-phase induction motor.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.438_439
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• 2009

This paper analyzes the undervoltage protection based on the dynamic stability of a PV system at fault conditions. A 3 MW PV system is modeled by Matlab/Simulink. Then, the distribution system interconnected with the PV system is modeled. This paper simulates the various fault types and analyzes the stability of the PV system at fault conditions. It is concluded that the undervoltage protection of the grid-connected PV system in Korea standard needs to be modified based on the results of the stability analysis.

• Journal of Advanced Marine Engineering and Technology
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• v.32 no.3
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• pp.421-429
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• 2008

Various kinds of ship are operated to transport cargo or passengers at sea in the world. Most of the important auxiliary machineries installed in those ships are fluid machineries such as pumps, compressors, and fans. A large percentage of fluid machinery is pumps which are classified turbo and positive displacement pumps. This paper analyzes only positive displacement pumps. This thesis has two aims: (a) to analyze the present status of pumps installed in merchant and training ships and (b) to find the correlation among sea going pump kW, port pump kW, total pump kW, GE kW, ME MCR, number of pumps, ME kgf, pump kgf. Based on ship's type, this paper seeks to find special characteristics as a result of analyzing head, flow rate, and kW. Moreover this paper analyzes and compares number of pumps, pump kW/ME MCR, pump kW/GE kW under the conditions of seagoing and berthing according to ship's type.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.8
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• pp.84-91
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• 2002

This paper analyzes the subsurface stress at the spherical contact using Hamilton equation, and with that data, calculates the fatigue limit under the variations of friction coefficient using fatigue theory. After rough surface being made, this paper figures out the random load generated by contacting to the rough surface, analyzes the stress of its subsurface, and calculates the fatigue limit of the rough surface using fatigue theory. The three parts of the fatigue theory are applied, which are critical plane theory, stress invariant theory and mesoscopic theory.

• Journal of Korea Technology Innovation Society
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• v.8 no.1
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• pp.94-115
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• 2005

The purpose of this study is to evaluate the economic value of a biotechnology in the middle of R&D and to examine strategies to manage a variety of risks and uncertainties intrinsic in research and development of biotechnologies through economic valuation in consideration of technological and industrial characteristics of the technology. To do this, this study analyzes the probability of commercial success of the technology development in qualitative terms, evaluates the quantitative value of the technology on the basis of a determined model, and proposes the implications on R&D strategy. In concrete, this study analyzes the economic value of the technology by constructing a decision tree reflecting the characteristics of the R&D process of the technology and draw the implications on the future R&D strategies of the technology.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.4
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• pp.503-508
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• 2012

Among the high distribution voltage consumers, high-capacity consumers are often applying the grounding resistance method in order to overcome demerits such as erroneous operation of the ground reply or potential increase in the battery at the accident of the isolated neutral system. In this paper, to prevent damage to CLR and GPT in the delay to block the breakdown in the resistance grounded neutral system, this study aims to provide a proper suggestion for continuous rating capacity of GPT to check the appropriateness of CLR size and reduce GPT burden. Thereupon, this study comparatively analyzes CLR current applied in general GPT and the current gained when CLR demanded in the system is used and analyzes the simulated system through simulation using PSCAD/EMTDC in order to suggest GPT's proper continuous rating capacity.

• Journal of Electrical Engineering and Technology
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• v.12 no.5
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• pp.1812-1820
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• 2017

This paper analyzes a symmetric active cell balancer for a battery management system. The considered cell balancer uses a forward converter in which the circuit structure is symmetric. This cell-balancing method uses fewer switches and is simpler than the previously proposed active cell-balancing circuits. Active power switches of this cell-balancing circuit operate simultaneously with the same pulse width modulation signals. Therefore, this cell-balancing circuit requires less time to be balanced than a previous bidirectional-forward-converter-based cell balancer. This paper analyzes the operational principles and modes of this cell balancer with computer-based circuit simulation results as well as experimental results in which each unbalanced cell is equalized with this cell balancer. The maximum power transfer efficiency of the investigated cell balancer was 87.5% from the experimental results. In addition to the experimental and analytical results, this paper presents the performance of this symmetric active cell-balancing method.