• Journal of Information Technology Services
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• v.19 no.6
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• pp.161-175
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• 2020

The current study aimed to develop the design principles for maker programs using virtual reality and apply them in developing a simulation mobile application. First, through collecting and analyzing the relevant studies and cases eight design principles with four components were derived. Then, these initial design components and principles were revised and improved in accordance with evaluations of an expert panel composed of three professors/researchers, two teachers, and two IT industrial experts. Based on the revised design principles, a VR simulation app for maker education was developed and evaluated on whether the principles were properly applied to the app development by the expert panel. The finalized eight design principles, as a research outcome, can contribute to the design and development of various types of educational programs that can replace the actual making experience even in educational fields where it is difficult to build maker spaces or provide materials and equipment. In the near future, empirical studies are expected to develop customized maker programs considering the characteristics, levels, and needs of students and verify their educational effectiveness.

• Journal of the Korean Ceramic Society
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• v.53 no.3
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• pp.273-281
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• 2016

This review examines computational simulations of thermoelectric properties, such as electrical conductivity, Seebeck coefficient, and thermal conductivity. With increasing computing power and the development of several efficient simulation codes for electronic structure and transport properties calculations, we can evaluate all the thermoelectric properties within the first-principles calculations with the relaxation time approximation. This review presents the basic principles of electrical and thermal transport equations and how they evaluate properties from the first-principles calculations. As a model case, this review presents results on $Bi_2Te_3$ and Si. Even though there is still an unsolved parameter such as the relaxation time, the effectiveness of the computational simulations on the transport properties will provide much help to experimental scientist researching novel thermoelectric materials.

• Management Science and Financial Engineering
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• v.20 no.1
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• pp.27-32
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• 2014

This paper introduces three different simulation algorithms of the shifted Poisson distribution. The first algorithm is the inverse transform method, the second is the rejection sampling, and the third is gamma-Poisson hierarchy sampling. Three algorithms have different regions of parameters at which they are efficient. We numerically compare those algorithms with different sets of parameters. As an application, we give a simulation method of the constant elasticity of variance model.

• Current Applied Physics
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• v.18 no.12
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• pp.1528-1533
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• 2018

The trajectories of adsorption and dissociation process of $O_2$ on the Al (111) surface were studied by the spinpolarized ab initio molecular dynamics method, and the adsorption activation energy was clarified by the NEB method with hybrid functionals. Three typical dissociation trajectories were found through simulation of $O_2$ molecule at different initial positions. When vertically approaches to the Al surface, the $O_2$ molecule tends to rotate, and the activation energy is 0.66eV. If $O_2$ molecule does not rotate, the activation energy will increase to 1.43 eV, and it makes the O atom enter the Al sublayer eventually. When the $O_2$ molecules parallel approach to the Al surface, there is no activation energy, due to the huge energy released during the adsorption process.

• Biotechnology and Bioprocess Engineering:BBE
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• v.10 no.5
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• pp.400-407
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• 2005

Reverse engineering is defined as the process where the internal structures and dynamics of a given system are inferred and analyzed from external observations and relevant knowledge. The first part of this paper surveys existing techniques for biosystem reverse engineering. Network structure inference techniques such as Correlation Matrix Construction (CMC), Boolean network and Bayesian network-based methods are explained. After the numeric and logical simulation techniques are briefly described, several representative working software tools were introduced. The second part presents our component-based software architecture for biosystem reverse engineering. After three design principles are established, a loosely coupled federation architecture consisting of 11 autonomous components is proposed along with their respective functions.

• Journal of the Semiconductor & Display Technology
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• v.2 no.4
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• pp.9-12
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• 2003

This paper describes a newly developed simulation environment for analysis and design of a plasma processing chamber based on first principles including complicated physical and chemical interactions of plasma, fluid dynamics of neutrals, and transport phenomena of particles. Capabilities of our simulator, named VIP-SEPCAD (Virtual Integrated Prototyping Simulation Environment for Plasma Chamber Analysis and Design), are demonstrated through a two dimensional simulation of an oxygen plasma chamber. VIP-SEPCAD can provide plasma properties such as spatiotemporal profiles of plasma density and potential, electron temperature, ion flux and energy, etc. By coupling neutral and particle transport models with a three moment plasma model, VIP-SEPCAD can also predict spatiotemporal profiles of chemically reactive species and particles exist in plasma.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.645-645
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• 2013

Applying a first-principles computational approach combining density-functional theory and matrix Green's function calculations, we have studied the effects [2+2] cycloaddition olligormerization of fullerene $C_{60}$ chains on their junction charge transport properties. Analyzing first the microscopic mechanism of the switching realized in recent scanning tunneling microscope (STM) experiments, we found that, in agreement with experimental conclusions, the device characteristics are not significantly affected by the changes in electronic structure of $C_{60}$ chains. It is further predicted that the switching characteristics will sensitively depend on the STM tip metal species and the associated energy level bending direction in the $C_{60}-STM$ tip vacuum gap. Considering infinite $C_{60}$ chains, however, we confirm that unbound $C_{60}$ chains with strong orbital hybridizations and band formation should in principle induce a much higher conductance state. We demonstrate that a nanoelectromechanical approach in which the $C_{60}-STM$ tip distance is maintained at short distances can achieve a metal-independent and drastically improved switching performance based on the intrinsically better electronic connectivity in the bound $C_{60}$ chains.

• The Journal of the Korean dental association
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• v.50 no.2
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• pp.58-63
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• 2012

The fundamental principles and the role of surgeons and orthodontists to produce successful results in orthodontic treatment combined with orthognathic surgery is not different from those of conventional procedures and FOS: surgery-first-orthodontic-treatment-later approach. The communication and cooperation between surgeon and orthodontist is of crucial importance. In FOS, the pre-surgical orthodontic preparation is not carried out in the patient's mouth, but in the mounted stone model and in addition to the simulation of tooth movement, to get a precise surgical occlusion, the entire steps of treatment should be simulated on the articulator as well. Right after the surgery, due to the instability of the occlusion, appropriate post operational care should be given according to the surgical technique applied to the mandible by use of final surgical wafer about 8 weeks.

• Journal of the Korean Ceramic Society
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• v.44 no.5 s.300
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• pp.166-172
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• 2007

In this study, magnetic properties of the strontium ferrite were theoretically investigated by Ab initio (first principle) method. The influences of various additives on the magnetic properties of the strontium ferrite were analyzed to designed new composition of the strontium ferrite system with high magnetic characteristics. As shown in the results, the total magnetization of the strontium ferrite was $42.55M_B$. Based on the DOS results, the magnetic characteristics of the strontium ferrite were mainly influenced by Fe atoms at 6 positions in the unit cell. Also the La-Mn strontium ferrite has the superior magnetic property than the Mn strontium ferrite.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.39 no.1 s.119
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• pp.8-15
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• 2007

In an effort to develop control strategies for the wet-end of paper machines, dynamic models for retention and formation processes have been developed. The retention process, including headbox total and filler consistencies, white water total and filler consistencies, the basis weight and the ash content of paper, can be modeled from first-principles (mass balances). To include the effect of wet-end chemistry variables, first-pass retention was included as a parameter dependent on operating conditions. In addition, dynamics of formation was simulated by developing an empirical model of formation and coupling with the dynamic models for the retention process. A series of experiments were performed using a pilot paper machine. The experimental results and the model predictions showed relatively good agreement.