• Journal of the Institute of Electronics Engineers of Korea SD
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• v.39 no.7
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• pp.1-6
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• 2002

For an optimum device design of nano-scale SOI devices, this paper describes the short channel effects of multi-gate structures SOI MOSFETs such as double gate, triple gate and quadruple gate, as well as a new proposed Pi gate using computer simulation. The simulation has been performed with different channel doping concentrations, channel widths, silicon film thickness, and vertical gate extension depths of Pi gate. From the simulation results, it is found that Pi gate devices have a large margin in determination of doping concentrations, channel widths and film thickness comparing to double and triple gate devices because Pi gate devices offer a better short channel effects.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.7
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• pp.767-772
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• 2011

Trajectory generation is important because it determines the walking stability, continuity, and performance of a body in motion. Generally, the Linear Inverted Pendulum Mode is used for trajectory generation; however, for the sake of simplicity, the trajectory in this mode does not allow vertical motions and pitching motions of the body. This paper proposes a new trajectory generation method called Extended Linear Inverted Pendulum Mode (ELIPM) that allows vertical motion as well as pitching motion. This method can also improve the performance of locomotion by controlling the stride and locomotion frequency of a body.

• Transactions of the Korean Society of Mechanical Engineers
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• v.12 no.4
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• pp.833-846
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• 1988

Two-phase flow heat transfer phenomena with flash evaporation inside a vertical tube were studied experimentally. Void fractions were measured using electrical probes, and the flow patterns were identified from the output voltage signal itself. The flow pattern as well as the beat transfer rates were changing along the axial distance from the tube inlet with the system pressure. As the pressure inside the tube decreases with fixed inlet temperature, the overall heat transfer coefficient through the tube wall and the boiling heat transfer coefficient inside the tube increase whereas the condensation heat transfer coefficient outside the tube decreases. The boiling heat transfer coefficient inside the tube measured by the experiments appeared to be somewhat larger than the value obtained from the Chen's correlation. Also, the flow patterns identified from present experiments are at the larger quality region of the low pattern map based on the transition criteria of Mishima and Ishii. This may be due to the non-equilibrium flashing phenomenon occurred at the nozzle exit and the tube inlet ; this also implies that the flow pattern of the two-phase flow depends strongly on the inlet conditions.

• International Journal of Highway Engineering
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• v.19 no.5
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• pp.97-106
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• 2017

PURPOSES: This study aims to evaluate the effects of vehicle dynamic behaviors on ride quality. METHODS : Simulation and field test were conducted to analyze the behavior of a driving vehicle. The simulation program CarSIM was applied and an INS (Inertial Navigation System) was used for field experiments. A small simulator was developed to simulate vehicle behavior such as roll, pitch, and bounce. The panels evaluated the ride quality in five stages from "very satisfied"to "very dissatisfied."Experiments were conducted on a total of 144 cases of vehicle behavior combinations. RESULTS :In both simulation and field tests, pitch is the largest and yaw the smallest. Especially in the field test, the amount of yaw is very low, about 7% of pitch and 18% of roll. The sensitive and extensive analysis conducted related ride quality with changing the frequency and amplitude. It was found that the most sensitive frequency range is 8 Hz across all amplitudes. Moreover, the combination of the roll and bounce was most sensitive to the ride quality at the low-frequency range. CONCLUSIONS : This result show that the vertical vehicle behavior (bounce) as well as the rotational behavior (roll and pitch) are highly correlated with ride quality. Therefore, it is expected that a more reasonable roughness index can be developed through a combination of vertical and rotational vehicle behavior.

• Journal of Korean Association for Spatial Structures
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• v.17 no.4
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• pp.167-174
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• 2017

The F3D(Free-Form Formwork 3D Printer) technology that manufactures EPS(Expanded Polystyrene) formworks for irregular-shaped concrete structures by 3D printers was developed to reduce the cost and time. Because of weak strength and low elastic modulus of the EPS, structural performance including lateral pressure by fresh concrete of the formwork that consisted of EPS should be investigated. In order to calculate lateral pressures acting on formwork, several variables including sizes, shapes of formwork, tangential force(fricition) between fresh concrete and formwork, and material properties of fresh concrete should be considered. However, current regulations have not considered the properties of concrete, only focused on vertical formwork. Galleo introduced 3-dimensional finite element analysis models to calculate lateral pressure on formwork. Thus, proposed finite element analysis model based on previous studies were verified for vertical formwork and irregular-shaped formwork. The test results were compared with those by FEM analysis. As a result, the test agrees well with the analysis.

• Proceedings of the Korean Geotechical Society Conference
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• 2001.03a
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• pp.453-458
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• 2001

Copper slag is produced about 700,000 tons annually though copper refining process in Korea. In the paper, a laboratory investigation was carried out to estimate the geotechnical properties of copper slag and examine the feasibility of using the copper slag as a substitute for conventional construction materials and the improvement of the soft clay deposit. The specific gravity of copper slag is 3.45, and pH is 7.83. And the size distribution of the copper slag is well graded, so usage of copper slag will be extended in Geotechnical engineering fields. Copper slag has the permeability of 3.502${\times}$10￣$^2$cm/sec, which is satisfied with the criterion of sand drainage materials.. At the same time, it is thought to be suitable material for sand mat since it meets JIS of grain size distribution. The content of CaO from steel slag is about 40 percent while that of CaO from copper slag is about 5 percent. Based on this fact, copper slag has less hardening property compared to steel slag. Therefore, copper slag can be used as vertical drains, filters, and sand mats for improving the soft deposit.

• Progress in Superconductivity and Cryogenics
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• v.4 no.1
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• pp.78-83
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• 2002

Since the KSTAR superconducting magnet structure should be maintained at a cryogenic temperature of about 4 K, even a small amount of heat might be a major cause of the temperature rise of the structure. The Joule heating by eddy currents induced in the magnet structure during the KSTAR operation was found to be a critical parameter for designing the cooling scheme of the magnet structure as well as defining the requirements of the refrigerator for the cryogenic system. Based on the Joule heating calculation, it was revealed that the bulk temperature rise of the magnet coil structure was less than 1 K. The local maximum temperature especially at the inboard leg of the TF coil structure increased as high as about 21 K for the plasma vertical disruption scenario. For the CS coil structure, the maximum temperature was obtained from the PF fast discharging scenario. This means that the vertical disruption and PF fast discharging scenarios are the major scenarios for the design of TF and CS coil structures, respectively. For the reference scenario, the location of maximum temperature spot changes according to the transient current variation of each PF coil.

• Korean Institute of Interior Design Journal
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• v.13 no.6
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• pp.107-114
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• 2004

The purpose of this study is to propose the unit plan for home office which can substitute the existing unvaried unit plan in housing and homogeneous working space in office building through the recognition of necessity and possibility about whether home-basedworkandhomeofficecanbeformedornot. Based on the above contents of a research, the following conclusions were summarized; 1. The unit plan of home office was divided into 'jointly-used type' and 'independent-separated type' in accordance with the relationship between housing and working space, 'dwelling-emphasis type' and 'working-emphasis type' in accordance with the grade of ranks between housing and working space. And the universal validity which could accept properly the dweller's characteristics was drawn by the above classification of unit types. 2. The required characteristics in a unit plan for home office were classified into flexibility, privacy, efficiency, identity, amenity. And the analyzing system of planning methodology was assigned according to dividing interior components into space-functional, space-designing interior facts. The planning methodology would have to be considered on the correlation with each required characteristic. As a result of the study, through a planning of independent-separated type, In especial, 'vertical-separated type', it was certificated that vertical-separated type could satisfy a variety of required characteristic in space-designing as well as space-functional aspect.

• The Journal of Advanced Prosthodontics
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• v.3 no.3
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• pp.132-135
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• 2011

PURPOSE. To study the distribution of various occlusal schemes as well as associated static occlusal relationship among Thais. MATERIALS AND METHODS. The subjects'occlusal schemes on the left and right sides were classified as canine protected occlusion, group function, or unclassified according to the definition from Glossary of Prosthodontic Terms ($8^{th}$ edition). In addition, the presence of occlusal interferences during mandibular excursions were recorded. The measurement of the horizontal overlap and vertical overlap was also performed. Chi-square, One-way ANAVA and Mann-Whitney U statistical tests were used with level of significance set at P=.05. RESULTS. Total of 104 subjects were included in this study. The ratio for male to female was 1.8 to 1. Average age of the population was $25.01{\pm}6.87$ years old. The mean vertical overlap and horizontal overlap were $1.94{\pm}1.20$ and $2.41{\pm}1.32$ mm respectively. The majority of the populations (68.3%) possessed group function occlusal scheme. For the remaining, 17.3% possess canine protected occlusion and 12.5% possess combination of both occlusal schemes. We also found that occlusal interference was presented in 20.2% of the population. The most common was protrusive interference (57.14%), the second was balancing interference (38.1%) and the third was working interference (4.1%). CONCLUSION. Among Thais, the most common occlusal scheme was group function, however there were no significant occlusal factors related to any particular occlusal scheme.

• Wind and Structures
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• v.29 no.6
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• pp.471-488
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• 2019

Wind pressure is a critical argument for the wind-resistant design of structures. The attempt, however, to explore the wind pressure field on buildings still encounters challenges though a large body of researches utilizing wind tunnel tests and wind field simulations were carried out, due to the difficulty in logical treatments on the scale effect and the modeling error. The full-scale measurement has not yet received sufficient attention. By performing a field measurement, the present paper systematically addresses wind pressures on the rectangular attic of a double-tower building. The spatial and temporal correlations among wind speed and wind pressures at measured points are discussed. In order to better understand the wind pressure distribution on the attic facades and its relationship against the approaching flow, a full-scale CFD simulation on the similar rectangular attic is conducted as well. Comparative studies between wind pressure coefficients and those provided in wind-load codes are carried out. It is revealed that in the case of wind attack angle being zero, the wind pressure coefficient of the cross-wind facades exposes remarkable variations along both horizontal and vertical directions; while the wind pressure coefficient of the windward facade remains stable along horizontal direction but exposes remarkable variations along vertical direction. The pattern of wind pressure coefficients, however, is not properly described in the existing wind-load codes.