• Transactions of the Korean Society of Mechanical Engineers B
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• v.22 no.5
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• pp.627-639
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• 1998

A combustion model for the incineration of municipal solid waste(MSW) in the stoker type incinerator was developed by considering the variation of physical composition of MSW. Theoretical analysis and numerical simulation for the combustion characteristics in incinerator were conducted by using the present model and the effects of compositional variation on the incineration characteristics of MSW was examined theoretically. It is found that large excess air enhances drying, but depresses volatilization. For the large value of moisture content, pyrolysis is fast but drying is slow. As the value of plastic content increases, devolatilization becomes slower. Larger amount of primary air supply to the rear side of stoker leads to increase the possibility of delaying the combustion.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.23 no.6
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• pp.1503-1513
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• 1998

This paper is related to a performance analysis of B-NT system, which is essential compositional equipment of B-ISDN access network. A simulator enabling performance analysis according to the change of network configuration topology and the change of user traffic is developed in this study. The developed B-NT, system simulator consists of graphic user interface module, simulation program automatic generator module, and B-NT system model library module. As examples of the results of performance analysis using the simulator, end-to-end user cell transmission delay time, queueing delay time in each system, and cell loss rate in the head node switch are presented. The simulator developed in this paper can be utilized in determining the network topology of B-NT system.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 1993.06a
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• pp.1137-1140
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• 1993

A dynamic-structure system is one that has the flexibility to change the system configuration automatically so as to operate in an optimal manner. A conceptural model for a dynamic-structure system is presented in this paper. In this model, the interchangeable components of the overall system are grouped together. Their activity levels are evaluated by an intelligent preprocessor that is associated with the group. A knowledge-based task distribution system evaluates the activity levels and makes decisions as to how the components operating below capacity should be shared with workcells that have similar components that are overloaded. Associated decision making can be effected through fuzzy logic and particularly the compositional rule of inference. A simulation example is given to illustrate the application of dynamic structuring.

• Geomechanics and Engineering
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• v.10 no.4
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• pp.423-436
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• 2016

Currently, there is a great interest in the coupling between multiphase fluid flow and geomechanical effects in hydrocarbon reservoirs and surrounding rocks. The ideal solution for this coupled problem is to introduce the geomechanical effects through the stress analysis solution and implement an algorithm, which assures that the equations governing the flow and stress analyses are obeyed in each time step. This paper deals with the implementation of a program (FORTRAN90 interface code), which was developed to couple conventional reservoir (ECLIPSE) and geomechanical (ABAQUS) simulators, using a partial coupling algorithm. The explicit coupled hydro-mechanical behavior of Iranian field during depletion and $CO_2$ injection is studied using the soils consolidation procedure available in ABAQUS. Time dependent reservoir pressure fields obtained from three dimensional compositional reservoir models were transferred into finite element reservoir geomechanical models in ABAQUS as multi-phase flow in deforming reservoirs cannot be performed within ABAQUS. The FEM analysis of the reservoir showed no sign of plastic strain under production and $CO_2$ injection scenarios in any part of the reservoir and the stress paths do not show a critical behavior.

• Structural Engineering and Mechanics
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• v.66 no.4
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• pp.505-513
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• 2018

Steam flooding is widely used in heavy oil reservoir with coupling effects among the formation temperature change, fluid flow and solid deformation. The effective stress, porosity and permeability in this process can be affected by the multi-physical coupling of thermal, hydraulic and mechanical processes (THM), resulting in a complex interaction of geomechanical effects and multiphase flow in the porous media. Quantification of the state of deformation and stress in the reservoir is therefore essential for the correct prediction of reservoir efficiency and productivity. This paper presents a coupled fluid flow, thermal and geomechanical model employing a program (MATLAB interface code), which was developed to couple conventional reservoir (ECLIPSE) and geomechanical (ABAQUS) simulators for coupled THM processes in multiphase reservoir modeling. In each simulation cycle, time dependent reservoir pressure and temperature fields obtained from three dimensional compositional reservoir models were transferred into finite element reservoir geomechanical models in ABAQUS as multi-phase flow in deforming reservoirs cannot be performed within ABAQUS and new porosity and permeability are obtained using volumetric strains for the next analysis step. Finally, the proposed approach is illustrated on a complex coupled problem related to steam flooding in an oil reservoir. The reservoir coupled study showed that permeability and porosity increase during the injection scenario and increasing rate around injection wells exceed those of other similar comparable cases. Also, during injection, the uplift occurred very fast just above the injection wells resulting in plastic deformation.

• Proceedings of the Korean Vacuum Society Conference
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• 1998.02a
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• pp.20-20
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• 1998

I Ion beam technology has recently attracted much interest because it has exciting t technological p아:ential for surface analysis, ion beam mixing, surface cleaning and etching i in thin film growth and semiconductor fabrication processes, etc. Es야~cially, ion beam s sputtering has been widely used for sputter depth profiling with x-photoelectron S spectroscopy (XPS) , Auger electron s$\pi$~troscopy(AES), and secondary-ion mass S야i따oscopy(SIMS). However, The problem of surface compositional ch없1ge due to ion b bombardment remains to be understo여 없ld solved. So far sputtering processes have been s studied by s따face an외ysis tools such as XPS, AES, and SIMS which use the sputtering p process again. It would be improbable to measure the modified surface composition profiles a accurately due to ion beam bombardment with surface analysis techniques based on sputter d depth profiling. However, recently Medium energy ion scattering spectroscopy(MEIS) has b been applied to study the sputtering of solid surface at ion bombardment and has been p proved that it has been extremely valuable in probing the surface composition 뻐d s structure nondestructively and quantita디vely with less than 1.0 nm depth resolution. To u understand the sputtering processes of solid surface at ion bombardment, The Molecular D Dynamics(MD) and Monte Carlo(MC) simulation has been used and give an intimate i insight into the sputtering processes of solid surfaces. In this presentation, the sputtering processes of alloys and compound samples at ion b bombardment will be reviewed and the MEIS results for the Ar+ sputter induced altered l layer of the TazOs thin film 뻐dd없nage profiling of Ar+ ion sputt얹"ed Si(100) surface will b be discussed with the results of MD and MC simulation.tion.

• Journal of the Korean Ceramic Society
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• v.48 no.6
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• pp.621-624
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• 2011

In order to deposit a homogeneous and uniform ${\beta}$-SiC films by chemical vapor deposition, we constructed the phase-diagram of ${\beta}$-SiC over graphite and silicon via computational thermodynamic calculation considering pressure(P), temperature(T) and gas composition(C) as variables in $C_3H_8-SiCl_4-H_2$ system. During the calculation, the ratio of Cl/Si and C/Si is maintained to be 4 and 1, respectively, and H/Si ratio is varied from 2.67 to 15,000. The P-T-C diagram showed very steep phase boundary between SiC+C and SiC region perpendicular to H/Si axis and also showed SiC+Si region with very large H/Si value of ~6700. The diagram can be applied not only to the prediction of the deposited phase composition but to compositional variation due to the temperature distribution in the reactor. The P-T-C diagram could provide the better understanding of chemical vapor deposition of silicon carbide.

• Journal of Electrochemical Science and Technology
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• v.2 no.3
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• pp.146-151
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• 2011

The formation of Li-Si-O phases, $Li_4SiO_4$ and $Li_2SiO_3$ from the starting materials SiO and $Li_2O$ are analyzed using Vienna Ab-initio Simulation (VASP) package and the total energies of Li-Si-O compounds are evaluated using Projector Augmented Wave (PAW) method and correlated the structural characteristics of the binary system SiO-$Li_2O$ with experimental data from electrochemical method. Despite $Li_2SiO_3$ becomes stable phase by virtue of lowest formation energy calculated through VASP, the experimental method shows presence of $Li_4SiO_4$ as the only product formed when SiO and $Li_2O$ reacts during slow heating to reach $550^{\circ}C$ and found no evidence for the formation of $Li_2SiO_3$. Also, higher density of $Li_4SiO_4$(2.42 g $ml^{-1}$) compared to the compositional mixture $1SiO_2-2Li_2O$ (2.226 g $ml^{-1}$) and better cycle capacity observed through experiment proves that $Li_4SiO_4$ as the most stable anode supported by better cycleabilityfor lithium ion battery remains as paradox from the point of view of VASP calculations.

• Korean Chemical Engineering Research
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• v.45 no.5
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• pp.515-522
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• 2007

In this study we have attempted to evaluate the technical feasibility of "BB-HY", which is depleted gas reservoir as a gas storage field, using the commercial compositional simulator "ECLIPSE 300". The "BB-HY" reservoir has an initial gas in place of 143 BCF which is relatively small, and its porosity and permeability are 19.5% and 50 md, respectively. For "BB-HY" gas reservoir, we have performed a feasibility analysis by investigating the cushion gas (or working gas), converting time to gas storage field, operation cycle, number of wells and the possible application of horizontal borehole as well. From the simulation results, it was found that the amount of cushion gas in "BB-HY" reservoir is required at least 50% of IGIP in order to operate stably as gas storage field. When one produces gas for longer time and hence the remaining gas in reservoir is less than optimal cushion gas, no technical problem was occurred as long as additional cushion gas is injected up to the optimal cushion gas. In the case of changing the operation cycle into producing gas for three months during winter season from producing five months, the result shows that either the cushion gas should be greater than 60% or the more number of wells should be drilled. Meanwhile, from the results of sensitivity analysis for the number of wells, in cases of operating six or eight vertical wells, the stable reproduction of the injected gas can not be possible in "BB-HY" gas reservoir since the remaining gas in reservoir is increased. Therefore, in "BB-HY" reservoir, at least ten vertical wells should be drilled for the stable operation of gas. This time, when three horizontal wells are additionally drilled including the existing two vertical wells, it was found that the operation of injection and reproduction of gas is relatively stable in "BB-HY" gas reservoir.

• Journal of Science of Art and Design
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• v.10
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• pp.183-218
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• 2006

Colors change in time corresponding with the value system and aesthetic consciousness of the time. The roles that colors play in painting can be divided into the formative role based on the contrast and harmony of color planes and the aesthetic role expressed by colors to represent the objects. The aesthetic consciousness of the orient starts with the Civility(禮) and Pleasure(樂), which is closely related with restrained or tempered human feelings. In the art world of the orient including poem, painting, and music, what are seen and felt from the objects are not represented in all. Added by the sentiment laid background, the beauty of the orient emphasizes the beauty of restraint and temperance, which has long been the essential aesthetic emotion of the orient. From the very inception of oriental painting, colors had become a symbolic system in which the five colors associated with the philosophy of Yin and Yang and Five Forces were symbolically connected with the four sacred animals of Red Peacock, Black Turtle, Blue Dragon, and White Tiger. In this color system the use of colors was not free from ideological matters, and was further constrained by the limited color production and distribution. Therefore, development in color expression seemed to have been very much limited because of the unavailability and unreadiness of various colors. Studies into the flow in oriental painting show that color expression in oriental painting have changed from symbolic color expression to poetic expression, and then to emotional color expression as the mode of painting changes in time. As oriental painting transformed from the art of religious or ceremonial purpose to one of appreciation, the mast visible change in color expression is the one of realism(simulation). Rooted on the naturalistic color expression of the orient where the fundamental properties of objects were considered mast critical, this realistic color expression depicts the genuine color properties that the objects posses, with many examples in the Flower & Bird Painting prior to the North Sung dynasty. This realistic expression of colors changed as poetic sentiments were fused with painting in later years of the North Sung dynasty, in which a conversion to light ink and light coloring in the use of ink and colors was witnessed, and subjective emotion was intervened and represented. This mode of color expression had established as free and creative coloring with vivid expression of individuality. The fusion of coloring and lyricism was borrowed from the trend in painting after the North Sung dynasty which was mentioned earlier, and from the trend in which painting was fused with poetic sentiments to express the emotion of artists, accompanied with such features as light coloring and compositional change. Here, the lyricism refers to the artist's subjective perspective of the world and expression of it in refined words with certain rhythm, the essence of which is the integration of the artist's ego and the world. The poetic ego projects the emotion and sentiment toward the external objects or assimilates them in order to express the emotion and sentiment of one's own ego in depth and most efficiently. This is closely related with the rationale behind the long-standing tradition of continuous representation of same objects in oriental painting from ancient times to contemporary days. According to the thoughts of the orient, nature was not just an object of expression, but recognized as a personified body, to which the artist projects his or her emotions. The result is the rebirth of meaning in painting, completely different from what the same objects previously represented. This process helps achieve the integration and unity between the objects and the ego. Therefore, this paper discussed the lyrical expression of colors in the works of the author, drawing upon the poetic expression method reflected in the traditional Flower and Bird Painting, one of the painting modes mainly depending on color expression. Based on the related discussion and analysis, it was possible to identify the deep thoughts and the distinctive expression methods of the orient and to address the significance to prioritize the issue of transmission and development of these precious traditions, which will constitute the main identity of the author's future work.