• Journal of the Institute of Electronics Engineers of Korea SP
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• v.37 no.4
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• pp.20-28
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• 2000

The error diffusion algorithm is good for reproducing continuous image to binary image. However the reproduction of edge characteristic is weak in power spectrum analysts of display error. In this paper, an error diffusion method which include pre-filter algorithm for edge characteristic enhancement is proposed Pre-filter algorithm is organized horizontal and vertical directional differential value and weighting function of pre-filter First, it is obtained the horizontal and vertical differential value from the peripheral pixels in original image using $3{\times}3$ Sobel operator Secondly weighting function of pre-filter is composed by function including absolute value and sign of differential value The improved Error diffusion algorithm using pre-filter, present a good result visually which edge characteristic is enhanced. The difference between orignal image and halftoning image is compared with edge-enhanced error diffusion algorithm by measuring the radially averaged power spectrum density.

• Journal of the Korean Society of Industry Convergence
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• v.26 no.1
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• pp.69-78
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• 2023

For this purpose, the research is to study the architectural characteristic of SooMaJaiJeon which is one of the DongHwaSa in the traditional wooden architecture by dividing it into three section-bracket, roof structure and frame structure. This study is largely divided into four stage-section do subject, research and actual measurement and conclusion. The whole process was consistently executed through detailed steps. The com position of this study is as follows. The 1^st chapter-the purpose, background, method, object and range of the research. The 2^nd chapter-the history of SooMajaiJeon. the 3^rd chapter-the structure of Dapo-style bracket has generally considered, the frame structure of Dapo-style, vertical and horizontal member and podium, the characteristic of bracket with member and the structure, design of bracket, roof structure. In the 4^th chapter, the conclusion of this study has been summarized, Dapo-style is the building that has deep symbolism and structural characteristic of traditional wooden architecture. The frame structure has a dominant regional characteristic and a typical part of typological classification in SooMaJaiJeon.

• The Journal of the Acoustical Society of Korea
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• v.33 no.6
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• pp.351-357
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• 2014

In this paper, flow noise characteristics of the hybrid vertical-axis wind turbine is investigated. Hybrid vertical-axis wind turbines consisting of two types of vertical-axis wind turbines, Savonius and Darrieus, are devised to maximize merits of one turbine and thus minimize demerits of the other turbine. In order to predict flow noise radiating from hybrid vertical-axis wind turbines, hybrid computatioinal aero acoustic techniques are used. First, unsteady flow fields around the turbine are predicted using computational fluid dynamics method. Then, the flow noise radiations from the turbines are predicted by applying acoustic analogy to the predicted flow fields. Based on numerical results, noise characteristics of a hybrid vertical-axis wind turbine is investigated and is compared with those of Savonius and Darrieus wind turbines.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.6C
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• pp.241-253
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• 2010

For seismic design of a vertical shaft, three-dimensional Finite Element (FE) analyses were performed to evaluate the accurate response of a vertical shaft and to apply a Response Displacement Method (RDM). Special attention is given to the evaluation of seismic base and response displacement of surrounding soil, estimation of load and loading method. Based on the result, it was found that shear wave velocity of seismic base greater than 1500m/s was appropriate for the seismic design. It was also found that double cosine method which evaluates a response displacement of surrounding soil was most appropriate to consider the characteristic of multi-layered soil. Finally, shape effect of the structure was considered to clarify the dynamic behavior of vertical shaft and it would be more economical vertical shaft design when a vertical shaft was analyzed by using RDM.

• International Union of Geodesy and Geophysics Korean Journal of Geophysical Research
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• v.22 no.1
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• pp.24-32
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• 1994

A special upper-air observation including airsonde and pibal observations was performed to investigate the characteristics features of the vertical distribution of the meteorological elements over Taegu on a selected clear day of each season from October 1991 to August 1992. The diurnal and seasonal variations of the vertical profiles of air temperature and mixing ratio were obtained from airsonde observations and wind speed and direction from pibal observations. The results of these special upper-air observations are as follow : The diurnal variation of the vertical distribution of air temperature reveals the characteristic features associated with the atmospheric boundary layer. All case days, except for the summer season, show upper-level inversion layer which influenced by surface high, and surface inversion layer produced by radiative cooling. The diurnal variation of mixing ratio shows the maximum vale at 1500 LST in both the upper and low levels, and is larger on the lower level than the upper level. The mixing ratio of the lower level is larger than that of the upper level. On the average the mixing ratio decrease with the height, and is the wettest on the summer case day and the driest on the winter case day. The diurnal variation of the wind velocity and direction are variable in the lower level with time and height, while they are steady in the upper level. On the average, the wind direction is southerly or southeasterly for the summer case day, westerly or northwesterly for the spring and fall case days, and northerly or northwesterly for the winter case day.

• Journal of Welding and Joining
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• v.35 no.2
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• pp.35-42
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• 2017

The GMA welding process involves large number of interdependent variables which may affect product quality, productivity and cost effectiveness. The relationships between process parameters for a vertical weldment and mechanical properties are complex because a number of process parameters are involved. To make the vertical-position welding, a method that predicts bead geometry and accomplishes the desired mechanical properties of the weldment should be developed. In addition, a reliable welding process and conditions must be implemented to reduce weld structure failure. In this study, the welding process analysis of investigates the interaction between the heat input and welding parameter(Welding current, Arc voltage, Welding speed) for predicting the weldment hardness.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.740-743
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• 2005

Most works of the large vertical ceiling structures have been performed by human manually. These works require much more operation costs, labors and times, etc. Beside most people avoid this works because of it's characteristic such as danger, dirty and difficulty. So necessity of automation for these works has been rising. This automation needs a wall climbing mobile vehicle because of the movement of platform large workspace. In this study, we aim at develop the wheel which can be used for vertical wall-climbing mobile robot using electromagnet wheel. The wheel proposed can be available for several working processes on structures which consist magnetic substance.

• Journal of the Korean GEO-environmental Society
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• v.13 no.7
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• pp.13-17
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• 2012

Recently, our ocean development paradigm is changing so that the development focus has been moved from the port facility developments to creating useful marine space. This paradigm accords well with the current green technology and helps the growth of service industries and the development from this paradigm can become a national land mark. Accordingly, the concept of creating marine waste landfill by the development of resource recycling technology has been introduced for eco-friendly space as an artificial island in future. Therefore, this study introduces the reactive vertical drainage method that is to pursue the purification of pollutants as well as stabilization of newly deposited soils in marine environments. To install the reactive vertical drainage piles for more effective feasibility and constructability, placements of drainage mid-layer are considered in the geotechnical viewpoint. Consolidation characteristics were evaluated by standard consolidation tests after several types of model test. As s result, the application of mid-layer drainage is strongly recommended in the reactive vertical drainage to quickly stabilize newly deposited soils. And vacuum consolidation method has better consolidation characteristic than vertical loading method in terms of the settlements predicted by additional stress for further use as an artificial island.

• 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.

• Structural Engineering and Mechanics
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• v.55 no.5
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• pp.1015-1035
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• 2015

A three-dimensional (3D) numerical analysis for the train-bridge interaction (TBI) system is actively developed in this study in order to investigate the vibration characteristics of rigid-frame reinforced concrete (RC) viaducts in both vertical and lateral directions respectively induced by running high-speed trains. An analytical model of the TBI system is established, in which the high-speed train is described by multi-DOFs vibration system and the rigid-frame RC viaduct is modeled with 3D beam elements. The simulated track irregularities are taken as system excitations. The numerical analytical algorithm is established based on the coupled vibration equations of the TBI system and verified through the detailed comparative study between the computation and testing. The vibration responses of the viaducts such as accelerations, displacements, reaction forces of pier bottoms as well as their amplitudes with train speeds are calculated in detail for both vertical and lateral directions, respectively. The frequency characteristics are further clarified through Fourier spectral analysis and 1/3 octave band spectral analysis. This study is intended to provide not only a simulation approach and evaluation tool for the train-induced vibrations upon the rigid-frame RC viaducts, but also instructive information on the vibration mitigation of the high-speed railway.