• Tunnel and Underground Space
• /
• 제9권3호
• /
• pp.204-213
• /
• 1999

NATM(New Austrian Tunnelling Method) uses a support system of shotcrete, rockbolt and steel support, which are installed after tunnel excavation. Recently, a lattice girder among these support system is used in tunnelling. A lattice girder is a new steel support developed in Europe for the replacement of an existing H-shaped steel set, which is reported to have some problems in installation. This is a triangular shape welded with steel rods and is a light-weight support system which enables fast and easy installation of porepolling. The major advantage of a lattice girder is the good bonding with shotcrete. In this study, to evaluate the applicability of a lattice girder in tunnelling in Korea, field tests were performed at a high speed railway tunnel with a large section. Also, features of lattice girder in field tests were compared with those of a H-shaped steel set respectively. Field tests proved that a lattice girder fully supported the initial earth pressure developed right after excavation and limited ground deformation effectively.

• Journal of the Korea Computer Graphics Society
• /
• 제26권4호
• /
• pp.17-26
• /
• 2020

We present a real-time GPU(Graphic Processing Unit) marching tetrahedra technique that extracts isosurfaces in the indexed mesh format from BCC(Body Centered Cubic) volume datasets. Compared to classical marching tetrahedra, our method shows better performance with little memory overhead. Our technique is composed of five stages. In the first stage, which needs to be done only once, we build min/max blocks that is to be used for empty space skipping to boost the performance. Next, we extract active blocks that contain the current isovalue. In the next two stages, we extract the edges and cells that contain the isosurface and then the final triangular mesh is generated in the last stage. When applied 512³ or higher resolution volume dataset, our technique shows up to 5 times speed improvement compared to the classical marching tetrahedra algorithm.

• Journal of the Institute of Electronics Engineers of Korea SP
• /
• 제41권6호
• /
• pp.279-283
• /
• 2004

In general, triangular shape filters are used in the filter bank when we extract MFCC feature parameters from the spectrum of the speech signal. A different approach, which uses specific filter shapes in the filter bank that are optimized to the spectrum of training speech data, is proposed by Lee et al. to improve the recognition rate. A principal component analysis method is used to get the optimized filter coefficients. Using a large amount of 4-digit telephone speech database, in this paper, we get the MFCCs based on the PCA-optimized filter bank and compare the recognition performance with conventional MFCCs and direct weighted filter bank based MFCCs. Experimental results have shown that the MFCC based on the PCA-optimized filter bank give slight improvement in recognition rate compared to the conventional MFCCs but fail to achieve better performance than the MFCCs based on the direct weighted filter bank analysis. Experimental results are discussed with our findings.

• 한국정보디스플레이학회:학술대회논문집
• /
• 한국정보디스플레이학회 2003년도 International Meeting on Information Display
• /
• pp.504-508
• /
• 2003

New banana-shaped achiral compounds, 4-chloro-1,3-phenylene bis [4-4(3-fluoro-9-alkenyloxy) phenyl-iminomethylbenzoate]s and 4-chloro-1,3-phenylene bis [4-4-(3-fluoro-10-alkanyloxy) phenyliminomethyl benzoate]s were synthesized by varying the substituent (X=H, F, or Cl); their electrooptical properties are described. The smectic phases, including a switchable chiral smectic C ($SmC^{\ast}$) phase, were characterized by differential scanning calorimetry, polarizing optical microscopy, and triangular method. The presence of vinyl end group at the terminals of linear side wings in the banana-shaped molecules induced a decrease in melting temperature. The smectic phase having the undecenyloxy group such $as-(CH_2)_9CH=CH_2$ showed ferroelectric switching, and its value of spontaneous polarization on reversal of an applied electric field was 2250 $nC/cm^2$, while the value of spontaneous polarization of the smectic phase having the decanyloxy group such as $-(CH2)_9CH_3$ was 3700 $nC/cm^2$. We could obtain the ferroelectric phase with low isotropic temperature by varying the end group at the terminals of linear side wings in the banana-shaped achiral molecules.

• The Journal of the Korea Contents Association
• /
• 제8권4호
• /
• pp.63-70
• /
• 2008

This paper presents a method of PRI do-interleaving for LASER pulse signals. When the PRI of LASER pulse is periodically changed, the first deviation and the second deviation of TOA is used to calculate the PRI pattern of input LASER signals of receiver. If the standard deviation of the first difference of TOA is less than 5% of the average of the first difference of TOA, the PRI pattern of LASER signal is fixed or jittered type. If the standard deviation is larger than 5% of the average, those are triangular PRI patterns or sawtooth PRI patterns.

• Journal of the Society of Naval Architects of Korea
• /
• 제39권2호
• /
• pp.34-44
• /
• 2002

Approximately 70 percent of shop's hull plate consists of three-dimensional curved shell. Concerning with the research on the automation of plate forming many studies have been carried out for the last decade. The purpose of this study is to develop the simulator of heating on the basis of the reasonable mechanical model representing a heating phenomenon. The beating experiment has been carried out with varying parameters influencing on the results of heating information at the kinematics analysis, simulatorestimate the shape of deformed plate that process along the processing information. When we get the initial shape and the object shape, we calculate the processing information first, using kinematics analysis. In a simulator we estimate deformed shape from the processing information. After this we compare deformed shape and object shape. If the error of deformed shape and object shape is in the proper limits, that information is determined the final processing information. Else we repeat the process changing variable.

• Fashion & Textile Research Journal
• /
• 제15권2호
• /
• pp.202-209
• /
• 2013

This study suggests a new women's upper clothing based on traditional Korean costumes that utilize the Jatmulim. The Jatmulim is an example of the skill found in conditional Korean costumes and is of a small triangular shape. Jatmulim was developed in size, shape, and arrangement through the method of making and using children's Durumagi, the dancer's or shaman's Mongduri, and modern works. A total of five pieces of different women's clothing were suggested by applying the developed Jatmulim. In the first piece, the clothing is a woman's sleeveless blouse based on the construction of the Yoseon-Cheolik from the Joseon period and made with a larger sized Jatmulim in the back of the neckline and shoulders. In the second piece, the clothing is designed for a woman's jacket based on the Bansuui of the Joseon period with rectangular Jatmulim in the front neckline and at the end of the sleeves. In the third piece, the clothing is designed for a woman's sleeveless blouse based on the Danryeong with rectangular Jatmulim in the neckline. In the fourth piece, the construction of the Jeogori is applied to the clothing for making a woman's jacket that has a bigger sized Jatmulim in the front part as a decoration. In the fifth work, the clothing is designed for a sleeveless blouse based on the Dapho with a different sized arrangement of the Jatmulim in the neckline.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• 제33권3호
• /
• pp.917-926
• /
• 2013

This study presents the feasibility of fuzzy multi-criteria decision making (MCDM) techniques for the robust prioritization of projects. It is applied to water resources planning problem. Results from weighted sum method (WSM), analytic hierarchy process (AHP), revised analytic hierarchy process (R-AHP), and TOPSIS are compared with those from Fuzzy WSM, Fuzzy, AHP, Fuzzy R-AHP, and Fuzzy TOPSIS. For the calculation, all weights on criteria and the normalized data were obtained from the same investigation. As a result, the rankings from four MCDM techniques are slightly different while those from fuzzy MCDM show the comparatively consistent ranking. Therefore, it is desirable to use fuzzy MCDM technique when MCDM is used for the prioritization problem, since fuzzy MCDM can include the uncertain variability of input data and weighting values on criteria.

• Journal of Korean Society for Geospatial Information Science
• /
• 제5권2호
• /
• pp.77-85
• /
• 1997

Researches in the field of Computer Graphics and Geographical Information Systems(GIS) have extensively studied the method of photo-realistic landscape modelling, because it have become a commom requirement in applications such as flight simulators, mission rehearsal, and construction planning. A common approach to the display of terrain uses a Digital Elevation Model(DEM). DEM is an evenly spaced array of the terrain elevation data and can be obtained from stereo satellite data. With the DEM data, the process of 3D terrain modelling consists of three steps. The first step is to extract the meaningful data (such as peak, pit, passes...) from DEM data based on LOD(Level Of Detail) criteria. The second is to construct the 3D surface by TIN, which represents a surface as a set of non-overlapping continuous triangular facets of irregular size and shape. The third is a rendering of 3D terrain model. The goal of this research is a construction of 3D terrain with TIN. To do this, we are going to app]y Radial Sweep Algorithm. Radial Sweep Algorithm for generating TIN works quickly and efficiently. However, it does not solve the problem caused by the approximated nature of triangulated surface. To solve this problem, this research derive improved radial sweep algorithms with the optimal triangle definition.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• 제21권3호
• /
• pp.229-236
• /
• 2003

This study recorded an object using a digital video recorder, and then tried to estimate 3-D positional information and to reconstruct an image. Firstly, the accuracy of measurement results from a video recorder was evaluated and tested for an applicability, then it applied to a real object to construct 3-D digital model. This study assumed that there is no lens distortion in a video recorder, and all bundles should precisely pass through the projection center of a lens. The image size for orientations is determined by the size of CCD chip and the number of pixels. The average squared error from the result by a digital video recorder and that by triangular survey from 1-second theodolite shows 0.0173m error in x,y coordinates. Without knowing the accurate information on the lens distortion and the coordinates of the projection center, this study reasonably produces acceptable results in the reconstruction of 3-D model. In consequence, this study found that the image from a digital video camera can be reconstructed 3-D model only from the information on a camera type.