• Transactions of the Korean Society of Mechanical Engineers B
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• v.26 no.6
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• pp.893-901
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• 2002

Effect of boundary layer thickness on the flow characteristics around a rectangular prism has been investigated by using a PIV(Particle Image Velocimetry) technique. Three different boundary layers(thick, medium and thin)were generated in the Atmospheric Boundary Layer Wind Tunnel at Pusan National University. The thick boundary layer having 670 mm thickness was generated by using spires and roughness elements. The medium thickness of boundary layer($\delta$=270 mm) was the natural turbulent boundary layer at the test section floor with fairly long developing length(18 m). The thin boundary layer($\delta$=36.5 mm) was generated on the smooth panel elevated 70cm from the wind tunnel floor. The Reynolds number based on the free stream velocity(3 ㎧) and the height of the model(40 mm) was 7.9$\times$10$^3$. The mean velocity vector fields and turbulent kinetic energy distributions were measured and compared. The effect of boundary layer thickness was clearly observed not only in the length of separation bubble but also in the location of reattachment point. The thinner the boundary layer thickness, the higher the turbulent kinetic energy Peak around the model roofbecame. It is strongly recommended that the height ratio between the model and the approaching boundary layer thickness should be encountered as a major parameter.

• Conservation Science in Museum
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• v.26
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• pp.161-182
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• 2021

A jungwangu, a type of medium-sized mortar, is a firearm with a barrel and a bowl-shaped projectileloading component. A bigyeokjincheonroe (bombshell) or a danseok (stone ball) could be used as a projectile. According to the Hwaposik eonhae (Korean Translation of the Method of Production and Use of Artillery, 1635) by Yi Seo, mortars were classified into four types according to its size: large, medium, small, or extra-small. A total of three mortars from the Joseon period have survived, including one large mortar (Treasure No. 857) and two medium versions (Treasure Nos. 858 and 859). In this study, the production method for medium mortars was investigated based on scientific analysis of the two extant medium mortars, respectively housed in the Jinju National Museum (Treasure No. 858) and the Korea Naval Academy Museum (Treasure No. 859). Since only two medium mortars remain in Korea, detailed specifications were compared between them based on precise 3D scanning information of the items, and the measurements were compared with the figures in relevant records from the period. According to the investigation, the two mortars showed only a minute difference in overall size but their weight differed by 5,507 grams. In particular, the location of the wick hole and the length of the handle were distinct. The extant medium mortars are highly similar to the specifications listed in the Hwaposik eonhae. The composition of the medium mortars was analyzed and compared with other bronze gunpowder weapons. The surface composition analysis showed that the medium mortars were made of a ternary alloy of Cu-Sn-Pb with average respective proportions of (wt%) 85.24, 10.16, and 2.98. The material composition of the medium mortars was very similar to the average composition of the small gun from the Joseon period analyzed in previous research. It also showed a similarity with that of bronze gun-metal from medieval Europe. The casting technique was investigated based on a casting defect on the surface and the CT image. Judging by the mold line on the side, it appears that they were made in a piece-mold wherein the mold was halved and using a vertical design with molten metal poured through the end of the chamber and the muzzle was at the bottom. Chaplets, an auxiliary device that fixed the mold and the core to the barrel wall, were identified, which may have been applied to maintain the uniformity of the barrel wall. While the two medium mortars (Treasure Nos. 858 and 859) are highly similar to each other in appearance, considering the difference in the arrangement of the chaplets between the two items it is likely that a different mold design was used for each item.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.1
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• pp.413-416
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• 2005

Developement of computer and digitalizing of medical implement are being caused digitalizing of medical image. Medical Images are being managed more by PACS. In this situation comes out many problem about ownership, the right of properity of the medical images and notice wheather the data are modified. Digital watermarking can solve this problem. The proposed schemes have a two weak point that Non-blind method need a original image and Blind method use gaussian watermarking. In this paper, we propose a blind watermarking using binary image in order to easily recognize result of watermark This proposed scheme using wavelet transform and Circular Input method that input in medium-band of frequency domain.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.12 no.1
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• pp.61-71
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• 2017

Local festival in Korea has developed quantitatively as well qualitatively. Driving force of local festival's development is local governments' active supports. Many Local government support local festival opening actively to accomplish economic activation. Activation of local festivals is good chance to local start-up companies. Local start-up companies don't have well known brand, and wide distribution network. But they can sell their products to visitors in local festival. And if fortune smiles upon them, they can get big buyers in local festivals. If so, what factors can contribute to a increase sales of local start-up companies? Different from existing research that focus on tour industrial outcome, we will focus on effect of festival service quality on increase sales. The survey is using structured questionnaire, we surveyed visitors who visit local start-up companies' booth in festival site. According to survey result, first, each dimensions of festival service quality do not effect on purchase intention directly except empathy dimension. Second, each dimensions of festival service quality effect on purchase intention by a medium of local image indirectly except assurance dimension. And purchase intention have a great effect on purchase action. Through the results, we can confirm festival service quality effect on purchase intention by a medium of local image indirectly. we suggest that improving festival service quality can effect on sales increase of local start-up companies, and for the purpose of sales increase, local government must improve local image at first.

• Current Optics and Photonics
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• v.8 no.3
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• pp.215-224
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• 2024

In medium- and long-range optical imaging systems, atmospheric turbulence causes blurring and distortion of images, resulting in loss of image information. An image-restoration method based on an adaptive feature-fusion multi-input-multi-output (MIMO) dense U-shaped network (Unet) is proposed, to restore a single image degraded by atmospheric turbulence. The network's model is based on the MIMO-Unet framework and incorporates patch-embedding shallow-convolution modules. These modules help in extracting shallow features of images and facilitate the processing of the multi-input dense encoding modules that follow. The combination of these modules improves the model's ability to analyze and extract features effectively. An asymmetric feature-fusion module is utilized to combine encoded features at varying scales, facilitating the feature reconstruction of the subsequent multi-output decoding modules for restoration of turbulence-degraded images. Based on experimental results, the adaptive feature-fusion MIMO dense U-shaped network outperforms traditional restoration methods, CMFNet network models, and standard MIMO-Unet network models, in terms of image-quality restoration. It effectively minimizes geometric deformation and blurring of images.

• Journal of Fashion Business
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• v.10 no.4
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• pp.16-28
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• 2006

The purpose of this study is to investigate the content and changes of modern Korean men's wear advertisement from the 1960s to the 1990s by reviewing fashion magazines and pictorials. Research problems were as follows.; First, analyze the types and their units of measurement in men's fashion advertisements from 1962 to 1998. Second, examine the differences of quantitative change in men's fashion advertisements according to each period. The total 857 advertisements were selected from Shin Dong-A, Joongang Magazine, and Bokjangwolbo from 1972 to 1998. For analyze the result, frequency analysis and $x^2$-test were used. Results were as follows. First, through the review of literatures and pre-tests, 6 units of measurement were identified. They were product type(formal wear, casual wear, sports wear, dress shirts, accessory, inner wear, fabric and the others), brand type(national brand, licensed brand, imported brand, others), appeal type(image, product, others), representation type(photograph, illustration, others), medium type(man, product, others), and color type of advertisement(black & white picture, color picture). Second, for the types of advertisements, formal wear, national brand, image appeal, figure medium, photograph for presentation and color picture are the most frequently shown in men's fashion advertisements from 1962 to 1998. Third, for product, more accessory advertisements were found than the clothing in the 60s and the 70s, and casual wear advertisements in the 80s and formal wear advertisements in the 90s were dominated. National brand type was dominant through all four period. Product appeal type in the 60s and the 70s and image appeal type in the 80s and the 90s were prevailed. For medium, product type in the 60s and the 70s and figure type in the 80s and the 90s were dominated. Black & white picture in the 60s and the 70s and color picture in the 80s and the 90s were prevailed. Lastly, photograph was the most frequently used for presentation type through all periods.

• Journal of the Korean Society of Clothing and Textiles
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• v.18 no.5
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• pp.749-764
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• 1994

It was assumed that a consumer forms images of all the factors related to clothing merchandise such as trademarks, stores, products and prices that he/she perceives in the market and those images deforming his/her preference for a particular piece of clothes and intention of purchase. Under this assumption, this research was designed to find out important factors of clothes that help a consumer form an image of the clothes, among other attributes of the merchandise, and how this image is related to the existing extraneous variables such as the trademark image, the consumer's self image, the price, etc. in leading the consumer to purchase the particular clothes in the end. In the empirical research, a preliminary survey was conducted to select brands of womenswear that were suitable for this study and as the result, 16 brands were chosen. Then one trademark, one store and two products from each of the 16 brands were selected. With these materials, 32 stimulus sheets were prepared, and each of them was composed of 3 photos of a brand's catalog and logo, the interior of a selected store that carried products of the brand, and formal suits selected from each brand's spring/summer 1993 collections. Subjects were 460 women in the age groups of 20-50s who live in Seoul Metropolitan area. Each of the subjects was provided with a survey questionnaire and 16 stimulus sheets. The main findings of this research prove that consumers follow a certain selection process model when they purchase clothes: consumers, first, from images of merchandise based on the trademarks, stares, and products and those formed images work il.: medium variables and in the end they help the consumers decide whether to buy the products.

• Journal of Bio-Environment Control
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• v.20 no.2
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• pp.101-108
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• 2011

The small and medium sprayer has developed to spray well fruit trees and roadside trees with pesticides for pests control within 60 meters. This study was carried out to analyze and evaluate its performance using image processing. While it sprayed with pesticides on the area of 20m in width and 60m in length, it was experimented 5 places by 5m from 0 to 25m width and 6 places by 10m from 10 to 60m length. The experimental image data of each sheet on places were averaged after binarization process. According to the image data, it was sprayed on all working area. However, when sprayer moved 0.3m/s velocity, the place at 15m of width and 30m of length was sprayed more than any other sprayed area, but the place at 15m of width and 60m of length was sprayed less.

• Journal of the Korean Society of Radiology
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• v.15 no.1
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• pp.29-35
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• 2021

The purpose of this study was to investigate whether there is a difference in image quality before and after reducing the amount of contrast medium in cerebral hemorrhagic patients who periodically follow up CT, and after reducing the amount of contrast medium, the image before and after reduction was examined, and the image quality was assessed by setting ROI at each vessel location using MMWP program. First Rt. CCA, Lt.CCA. Rt.MCA, Lt.MCA and Basilar Artery each got an ROI. Second, the mean and standard deviation values for the ROI were obtained. Third, SNR and CNR were obtained through the average and standard deviation values obtained. T-test statistics show that the SNR and CNR values obtained show that the result values for SNR are Rt.CCA 0.765, Ltd.CCA 0.871, Rt.MCA 0.343 LT.MCA 0.235, Basilar alternative 0.916, result value for CNR Rt.CCA 0.088, Ltd.CCA 0.069, Rt.MCA 0.818, Let's...MCA 0.579 and Basilar Artery 0.878. The results obtained through the obtained SNR and CNR values showed no difference in the quality of the images before and after reducing contrast medium. Therefore, we hope that this study will be an indicator that reduces the burden on contrast agents on patients who do CT examinations periodically.

• Journal of Biosystems Engineering
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• v.31 no.6 s.119
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• pp.514-523
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• 2006

Production of green pepper has been increased due to customer's preference and a projected ten-year boom in the industry in Korea. This study was carried out to develop an automatic grading and sorting system for green pepper using machine vision. The system consisted of a feeding mechanism, segregation section, an image inspection chamber, image processing section, system control section, grading section, and discharging section. Green peppers were separated and transported using a bowl feeder with a vibrator and a belt conveyor, respectively. Images were taken using color CCD cameras and a color frame grabber. An on-line grading algorithm was developed using Visual C/C++. The green peppers could be graded into four classes by activating air nozzles located at the discharging section. Length and curvature of each green pepper were measured while removing a stem of it. The first derivative of thickness profile was used to remove a stem area of segmented image of the pepper. While pepper is moving at 0.45 m/s, the accuracy of grading sorting for large, medium and small pepper are 86.0%, 81.3% and 90.6% respectively. Sorting performance was 121 kg/hour, and about five times better than manual sorting. The developed system was also economically feasible to grade and sort green peppers showing the cost about 40% lower than that of manual operations.