• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.20 no.6
• /
• pp.773-777
• /
• 2011

Conventional ultrasonic thickness measurement is to be considered as the assumption that the ultrasonic velocity is known. In actual applications the velocity is often not well known and access is often limited to one side. This paper aims at determining the ultrasonic velocity and thickness of plates with parallel or wedged surfaces using contact measurements made on one surface only. For wedged plates the thickness at one point and the wedge angle are determined. Equations are used for determining the ultrasonic velocity, thickness and wedge angle of the plate based on the times-of-flight measured by two contact transducers coupled to one surface. The time-of-flight of the obliquely reflected longitudinal wave echo was measured as a function of the separation between the two transducers. In addition, a simulation was made for comparing the experimental data and a FEM image. Experiments and simulations were performed on flat and wedged plates of aluminium materials; the calculated results for the unknown quantities are generally agreed with them to some degree.

• Journal of Korean Society for Atmospheric Environment
• /
• v.20 no.4
• /
• pp.437-450
• /
• 2004

Extensive forest fire activities occurred across the border in Russia, particularly east of Lake Baikal between the Amur and Lena rivers in May 2003. These forest fires released large amounts of particulates and gases into the atmosphere, resulting in adverse effects on regional air quality and the global radiation budget. Smoke pollution from the Russian fires near Lake Baikal was transported to Korea through Mongolia and eastern China. On 20 May 2003, a number of large fires were burning in eastern Russian, producing a thick, widespread pall of smoke over much of Northeast Asia. In this study, separation technique was used for aerosol retrieval application with imagery from MODIS aboard TERRA satellites. MODIS true-color image shows the location of fires and the grayish color of the smoke plumes over Northeast Asia. Aerosol optical thckness (AOT) retrieved from the MODIS data were compared with fire hot spots, ground-based radiation data and TOMS -based aerosol index data. Large AOT, 2.0-5.0 was observed on 20 May 2003 over Korea due to the influence of the long range transport of smoke aerosol plume from the Russian fires, while surface observed fine mode of aerosol size distribution increased.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2015.10a
• /
• pp.27-29
• /
• 2015

Based on IALA guidelines, the fundamental requirements of radar system for vessel traffic services are analyzed in this paper. target separation, target position accuracy, target track accuracy of X-band radar and recommended test conditions are analyzed. Also, in order to check if it satisfies the requirement of target position accuracy from IALA guideline, the test is carried out through processing of radar raw image acquired at VTS center.

• Korean Institute of Interior Design Journal
• /
• no.27
• /
• pp.111-119
• /
• 2001

The purpose of this study was to the characteristics of the interior space composition for luxurious apartments and the trend of interior design. Surveying visits were made to 30 model houses for which individual apartments of 8 million Won or more per pyeong (about 3.30 square meters) were on sale from December 1999 through November 2000 in Seoul and suburb area, pundang. The major finding were summarized as follows; (1) The characteristics of the planes indicated that the living-room separation type accounted for the majority, which was not generally different from common apartments. The master zone divided several room. The main room which conventionally played the roles of the family gathering space and the second room shared by family members, was designed exclusively for husband and wife. Distinctively separated from the other spaces, it was to be used for personalized space, together with bathroom for the couple, dressing room, or study. Attempts were made for the high-class apartments to get away from the common uniformed apartments, such as the yard-type balcony or the second entrance in consideration of the moving path. (2) The characteristics of the interior designs showed that the detailed attention was paid to every composing element for the emphasis of the high quality image. The factors determining the quality were finishing materials, kitchen furniture, hygienic ceramics, electrical appliances water supply equipment, or functional storage closet.

• Journal of the Korean Society of Costume
• /
• v.54 no.5
• /
• pp.125-138
• /
• 2004

This study has the aim of defining the special characteristics and images of the rainbow colored fashion by understanding the theoretical bases of rainbow colors and analyzing rainbow colored fashion images in historical materials. western and folk costumes. modern fashion design. Giving careful consideration to the rainbow colored fashion makes it possible to develope the innovative way of fashion design to satisfy the needs of color usual for designers and colorists. To obtain the purposes, document study and survey study have been executed. The results of this study are as follows. In document studies, the beginning of rainbow colored fashion went back in ancient Egypt. Also saikdong of korea, poncho of indians are the examples of the rainbow colored fashion. The rainbow colored fashion were put on a man of position in principle ceremony for ornaments. In survey studies, the clothing perception characteristics in rainbow colored fashion were analyzed. Main factors of perception characteristics In the rainbow colored fashion are ＇closed form＇, ＇whole＇, ＇indeterminate＇, ＇rounded＇, ＇planar separation＇ The factors that affect the perception of rainbow colored fashion are ＇closed form＇ and ＇indeterminate＇ characteristics. And rainbow colored fashion images and clothing perception characteristics can be classified into four main images : Vigorous, Colorful/fairy, Fresh, Mysterious/brilliant. Therefore. this study is to systematize the characteristics and images of rainbow colors. Based on the results makes it possible to adapt rainbow colors to fashion design efficiently, for the suggested design elements and color palettes include basic three fashion design elements color. texture. form.

• Wind and Structures
• /
• v.17 no.5
• /
• pp.515-535
• /
• 2013

The present study aims to investigate characteristics of the flow structures around the Ahmed body by using both experimental and numerical methods. Therefore, 1/4 scale Ahmed body having $25^{\circ}$ slant angle was employed. The Reynolds number based on the body height, H and the free stream velocity, U was $Re_H=1.48{\times}10^4$. Investigations were conducted in two parts. In the first part of the study, Large Eddy Simulation (LES) method was used to resolve the flow structures around the Ahmed body, numerically. In the second part of the study the particle image velocimetry (PIV) technique was used to measure instantaneous velocity fields around the Ahmed body. Time-averaged and instantaneous velocity vectors maps, streamline topology and vorticity contours of the flow fields were presented and discussed in details. Comparison of the mean and turbulent quantities of the LES results and the PIV results with the results of Lienhart et al. (2000) at different locations over the slanted surface and in the wake region of the Ahmed body were also given. Flow features such as critical points and recirculation zones in the wake region downstream of the Ahmed body were well captured. The spectra of numerically and experimentally obtained stream-wise and vertical velocity fluctuations were presented and they show good consistency with the numerical result of Minguez et al. (2008).

• Journal of radiological science and technology
• /
• v.44 no.5
• /
• pp.465-471
• /
• 2021

Dual-energy X-ray imaging (DEI) techniques can provide X-ray images that a certain material is suppressed or emphasized by combining two X-ray images obtained from two different x-ray spectrum. In this paper, a single-shot DEI, which uses stacked two detectors (i.e., multilayer detector), is proposed to reduce the patient dose and increase throughput in angiography. The polymethyl methacrylate (PMMA) and aluminum (Al) were selected as two basis materials for material decomposition, and material-specific images are reconstructed as a vector combination of these two materials. We investigate the contrast and noise performance of material-decomposed images using iodine phantoms with various concentrations and diameters. The single-shot DEI shows comparable performances to the conventional dual-shot DEI. In particular, the single-shot DEI shows edge enhancement in material-decomposed images due to the different spatial-resolution characteristics of upper and lower detectors. This study could be useful for designing the multilayer detector including scintillators and energy-separation filter for angiography purposes.

• Journal of Korea Multimedia Society
• /
• v.22 no.2
• /
• pp.136-145
• /
• 2019

The crowded environment of a domestic pig farm is highly vulnerable to the spread of infectious diseases such as foot-and-mouth disease, and studies have been conducted to automatically analyze behavior of pigs in a crowded pig farm through a video surveillance system using a camera. Although it is required to correctly separate occluding pigs for tracking each individual pigs, extracting the boundaries of the occluding pigs fast and accurately is a challenging issue due to the complicated occlusion patterns such as X shape and T shape. In this study, we propose a fast and accurate method to separate occluding pigs not only by exploiting the characteristics (i.e., one of the fast deep learning-based object detectors) of You Only Look Once, YOLO, but also by overcoming the limitation (i.e., the bounding box-based object detector) of YOLO with the test-time data augmentation of rotation. Experimental results with two-pigs occlusion patterns show that the proposed method can provide better accuracy and processing speed than one of the state-of-the-art widely used deep learning-based segmentation techniques such as Mask R-CNN (i.e., the performance improvement over Mask R-CNN was about 11 times, in terms of the accuracy/processing speed performance metrics).

• Journal of Korea Society of Digital Industry and Information Management
• /
• v.10 no.4
• /
• pp.29-35
• /
• 2014

The formula contains up between the text and the structural information, as well as their mathematical symbols. Research on-line or off-line recognition formula is underway actively used in various fields, and various forms of the equation are implemented recognition system. Although many documents are included in the various formulas, it is not easy to enter a formula into the computer. Recognition of the expression is divided into two processes of symbol recognition and structural analysis. After analyzing the location information of each character is specified to recognize the effective area after each symbol, and to the structure analysis based on the proximity between the characters is recognized as an independent single formula. Furthermore, analyzing the relationship between the front and back each time a combination of the position relationship between each symbol, and then to add the symbol which was able to easily update the structure of the entire formula. In this paper, by using a scanner to scan the book formula was used to interpret the meaning of the recognized symbol has a relative size and location information of the expression symbol. An algorithm to remove the formulas for calculation of the number of formula is present at the same time is proposed. Using the proposed algorithms to scan the books in the formula in order to evaluate the performance verification as 100% separation and showed the recognition rate equation.

• Korean Journal of Metals and Materials
• /
• v.48 no.5
• /
• pp.436-444
• /
• 2010

The hot tear susceptibility of Al alloys was investigated by using a constrained-rod mold designed to quantify 8 types of tear tendency. The severity of the crack was scored by 5 grades on a scale of 0 to 4, with 0 being "no crack formed" and 4 being "complete separation by crack". The Hot Tear Susceptibility index (HTS) which consists of crack type scores and position scores, was proposed to compare the hot tear tendency of Al alloys. A356.0 cast alloy and AA6061 wrought Al alloy showed an HTS value of 27.5 and 53 respectively. The effects of Si, Cu, and Mg content on hot tear tendency were also investigated with a constrained-rod mold. The variation of HTS values with alloying elements represents similar behavior in the variation of the solidification range in a pseudo binary phase diagram.