• Proceedings of the KSME Conference
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• 2001.06e
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• pp.81-86
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• 2001

Interfacial pressure jump terms based on the physics of phasic interface and bubble dynamics are introduced into the momentum equations of the two-fluid model for bubbly flow. The pressure discontinuity across the phasic interface due to the surface tension force is expressed as the function of fluid bulk moduli and bubble radius. The consequence is that we obtain from the system of equations the real eigenvalues representing the void-fraction propagation speed and the pressure wave speed in terms of the bubble diameter. Inversely, we obtain an analytic closure relation for the radius of bubbles in the bubbly flow by using the kinematic wave speed given empirically in the literature. It is remarkable to see that the present mechanistic model using this practical bubble radius can indeed represent both the mathematical well-posedness and the physical wave speeds in the bubbly flow.

• Journal of the Korean Vacuum Society
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• v.18 no.3
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• pp.151-163
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• 2009

The domestic development status of Inductively Coupled Plasma (ICP) simulator which is based on fluid model is explained. As each part which composes the unified simulator, electron heating module, charged and neutral particle transport module, surface reaction module including a sheath model, and GUI (Graphic User Interface) with pre- and post-processors are described in order. Also, we present data base status of chemical reaction and physical collision, which has been applied to the recently developed simulator until now. Lastly, some future plans of development are suggested.

• Journal of Computing Science and Engineering
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• v.3 no.4
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• pp.238-259
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• 2009

In this paper we discuss personal data management with mobile devices, an activity requiring the composition of services offered by standard suites of applications. We propose a data model and an interface model that allows users to define activities, tasks and services, to navigate among them according to the evolution of the personal situation as perceived and interpreted by the users themselves. The interface model acts as a lens exploring the situation, zooming into the details, covering different areas of the personal data, supporting the user in the role of a composer of personal services.

• Selected Papers of The Society of Naval Architects of Korea
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• v.2 no.1
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• pp.129-139
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• 1994

This paper describes a design model for the conceptual design of ships. Existing design models have problems such that their operating mode of batch versions cannot reflect the design procedures in reality. Reliability of the results is low because the performance estimations are based mainly on empirical formulas. To improve the problems of existing design models, a new design model has been developed. The new model consists of an interactive user interface, a database of main engines, a database of particulars of existing ships, and ten modules for performance estimations. To develop such a user-oriented system, the concept of graphical user interface (GUI) is adopted.

• Journal of the Optical Society of Korea
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• v.16 no.1
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• pp.57-62
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• 2012

Using continuous wave near-infrared spectroscopy, we measured time-resolved concentration changes of oxy-hemoglobin and deoxy-hemoglobin from the primary motor cortex following finger tapping tasks. These data were processed using partial least squares-discriminant analysis (PLS-DA) to develop a prediction model for a brain-computer interface. The tasks were composed of a series of finger tapping for 15 sec and relaxation for 45 sec. The location of the motor cortex was confirmed by the anti-phasic behavior of the oxy- and deoxy-hemoglobin changes. The results were compared with those obtained using the hidden Markov model (HMM) which has been known to produce the best prediction model. Our data imply that PLS-DA makes better judgments in determining the onset of the events than HMM.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.6
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• pp.898-904
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• 2003

Using the modified Irwin model and the modified Dugdale model, the plastic zone size near the interface crack tip in a ductile layer bonding two dissimilar elastic substrates is predicted. Validity of the models is examined by finite element method. The effects of several factors such as the mode mixity, T-stress and material properties are explored. The plastic zone size significantly decreases with the Poisson's ratio of the ductile layer.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2002.09a
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• pp.121-122
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• 2002

The main principle of radiation therapy is to deliver optimum dose to tumor to increase tumor cure probability while minimizing dose to critical normal structure to reduce complications. RTP system is required for proper dose plan in radiation therapy treatment. The main goal of this research is to develop dose model for photon, electron, and brachytherapy, and to display dose distribution on patient images with optimum process. The main items developed in this research includes: (l) user requirements and quality control; analysis of user requirement in RTP, networking between RTP and relevant equipment, quality control using phantom for clinical application (2) dose model in RTP; photon, electron, brachytherapy, modifying dose model (3) image processing and 3D visualization; 2D image processing, auto contouring, image reconstruction, 3D visualization (4) object modeling and graphic user interface; development of total software structure, step-by-step planning procedure, window design and user-interface. Our final product show strong capability for routine and advance RTP planning.

• The Journal of Information Systems
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• v.8 no.2
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• pp.91-110
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• 1999

Recently, searching agent systems to help purchase of products between business and customer have been actively studied in Electronic Commerce(EC). However, the most of comparative searching agent systems are only provided customers with searching results by the keyword-based search, and is not support the efficient decision models to be selected products considering the customer's requirements. This paper proposes the decision agent system applied decision model as well as searching functions based on the keyword-input to be selected useful products in EC. The proposed decision agent system is consist of the user interface, provider interface, decision model. Especially, as the example of the decision model, this paper is designed and implemented the prototype of decision agent system which is normalized the searching data and value of customer's preference weight as to each attribute, and orderly provided customers with computed results. This agent system is also carried out sensitive analysis according to the reflection ratio of the each attribute.

• Journal of Power System Engineering
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• v.9 no.4
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• pp.187-193
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• 2005

In this paper, we proposes a man-machine interface design for fault diagnosis system with inter-node search method in a Petri net model. First, complicated fault cases are modeled as the Petri net graph expressions. Next, to find out causes of the faults on which we focus, a Petri net model is analyzed using the backward reasoning of transition-invariance in the Petri net. In this step, the inter-node search method algorithm is applied to the Petri net model for reducing the range of sources in faults. Finally, the proposed method is applied to a fault diagnosis of a refrigeration system to confirm the validity of the proposed method.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.5 no.10
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• pp.1770-1782
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• 2011

A brain-computer interface (BCI) is a communication system that translates brain activity into commands for computers or other devices. In other words, BCIs create a new communication channel between the brain and an output device by bypassing conventional motor output pathways consisting of nerves and muscles. This is particularly useful for facilitating communication for people suffering from paralysis. Due to the low bit rate, it takes much more time to translate brain activity into commands. Especially it takes much time to input characters by using BCI-based typewriters. In this paper, we propose a brain-operated typewriter which is accelerated by a language prediction model. The proposed system uses three kinds of strategies to improve the entry speed: word completion, next-syllable prediction, and next word prediction. We found that the entry speed of BCI-based typewriter improved about twice as much through our demonstration which utilized the language prediction model.