• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.25 no.2
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• pp.75-81
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• 1989

In this paper, the authors describe on the field experiment of the newly designed actual stow net, standing on the result of the model experiment to examine the performance of the conventional net and the newly designed net, presented in two previous reports of this series. Concurrently the additional experiment to find out the possibility of changing of operating system from the side to the stern was carried out. 1. Fundamental shape of the experimented net was 20 times aslarge asthe newly designed model net. Performance of the net was detected by using two ultrasonic echo sounders: one was set downward at the top-most spreader of the shearing device to detect the opening height of the device from the sea bed, and the other sidewise at the starboard top-most spreader to detect the top-most opening width of the devices. Opening height of the newly designed net showed about 3m smaller than the conventional net at slow current of 0.6m/sec and less but it overcome 1m at speedy current of 0.8m/sec and more. Opening width of the newly designed net was 1.4 times as large as that of the conventional net, ant the front projection area of the newly designed net mouth was estimated as 1.3~1.6 times as large as that of the conventional net. 2. The experiment on the stern operating system was tightly limited by the structure of the ship employed in the experiment, which was a stern trawler of 2275 GT. The ship confronted by the wind with main anchor, while the net was put over the stern slipway and the hauling line of shearing device was operated through the top rollers of gallows. The experiment was very suggestive in the view point to mechanize the operating system, and so to decrease the man power except the following question. The of bow-stern line of ship, and that of net is much different.

• Korean Journal of Heritage: History & Science
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• v.54 no.2
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• pp.78-97
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• 2021

Seojangdaeyajodo is a drawing of military night training on February 12th (lunar leap month), 1795. Focusing on the Seojangdaeyajodo, the characteristics and of the costumes worn by various types of officials were examined. There were 34 officials located near King Jeongjo in and around Seojangdae, with 27 Dangsanggwan and 7 Danghagwan. They wore three types of costumes, including armor, yungbok, and military uniforms. All of the twelve armor wearers and the five officials wearing yungbok were dangsanggwan, and the military uniform wearers included eleven dangsanggwan and six danghagwan. For the shape of the armor, the armor relics of General Yeoban, suitable for riding horses, and the armor painting of Muyedobotongji were referenced, and the composition of the armor was based on practicality. The armor consists of a helmet, a suit of armor, a neck guard, armpit guards, arm guards, and a crotch guard. The color of the armor was red and green, which are the most frequently used colors in Seojangdaeyajodo. The composition of yungbok was jurip, navy cheollik, red gwangdahoe, socks made of leather, and suhwaja. The composition of the military uniform was a lined jeolrip, dongdari, jeonbok, yodae, jeondae, and suhwaja. There were differences in the fabrics used in dangsanggwan and danghagwan military uniforms. Dangsanggwan used fabric with depictions of clouds and jewels, and danghagwan used unpatterned fabric. Moreover, jade, gold, and silver were used for detailed ornamental materials in dangsanggwan. The weapons included bows and a bow case, a sword, a rattan stick, wrist straps, and a ggakji. In the records of the King Jeongjo period, various colored heopsu were mentioned; the colors of the dongdari and jeonbok of dangsanggwan and danghagwan were referenced in various colors. It was presented as an illustration of costumes that could be used to produce objects accurately reflecting the above historical results. The basic principle of the illustration was to present the modeling standards for 3D content production. Samples of form, color, and material of the corresponding times and statuses were presented. The front, the side, and the back of each costume and its accessories were presented, and the colors were presented in RGB and CMYK.

• Explosives and Blasting
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• v.30 no.2
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• pp.29-42
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• 2012

Variables influencing the free face movement due to rock blasting include the physical and mechanical properties, in particular the discontinuity characteristics, explosive type, charge weight, burden, blast-hole spacing, delay time between blast-holes or rows, stemming conditions. These variables also affects the blast vibration, air blast and size of fragmentation. For the design of surface blasting, the priority is given to the safety of nearby buildings. Therefore, blast vibration has to be controlled by analyzing the free face movement at the surface blasting sites and also blasting operation needs to be optimized to improve the fragmentation size. High-speed digital image analysis enables the analyses of the initial movement of free face of rock, stemming optimality, fragment trajectory, face movement direction and velocity as well as the optimal detonator initiation system. Even though The high-speed image analysis technique has been widely used in foreign countries, its applications can hardly be found in Korea. This thesis aims at carrying out a fundamental study for optimizing the blast design and evaluation using the high-speed digital image analysis. A series of experimentation were performed at two large surface blasting sites with the rock type of shale and granite, respectively. Emulsion and ANFO were the explosives used for the study. Based on the digital images analysis, displacement and velocity of the free face were scrutinized along with the analysis fragment size distribution. In addition, AUTODYN, 2-D FEM model, was applied to simulate detonation pressure, detonation velocity, response time for the initiation of the free face movement and face movement shape. The result show that regardless of the rock type, due to the displacement and the movement velocity have the maximum near the center of charged section the free face becomes curved like a bow. Compared with ANFO, the cases with Emulsion result in larger detonation pressure and velocity and faster reaction for the displacement initiation.