• Journal of Fisheries and Marine Sciences Education
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• v.11 no.2
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• pp.203-215
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• 1999

Floating debris was recorded from a training ship, Kaya, of Pukyong National University with about 12 knots speed at July 19~21, 1999 and July 24~26. The sampled area is the Yellow Sea (YS) connected from Cheju Is. of Korea to Qindao harbor of China, divided into 88 unit segments on survey routes. Debris fabrication materials were categorized with 6 items using the following; man-made or natural wood items, paper and cardboard, nylon netting and rope, styrofoams, vinyl and plastics, floating metal and glass containers. All identified items within a $120{\pm}20m$ wide band were recorded but ignored if beyond this boundary. The results of distribution of floating debris in the area are as follows: 1. The greatest quantities of marine debris discovered during the survey were $184pieces\;per\;km^2$ near Qindao harbor. The next polluted areas, Sohuksan islands, positioned in the eastern part of YS were scattered in about $40pieces/km^2$ or so. 2. Among items, woods, paper and cardboard, vinyl and plastics were found out near Qindao Coast of China. On the other hand, there were many styrofoams, nylon netting and rope near the area of Sohuksan islands in the eastern part of YS. 3. The distribution densities of western part of YS near Qindao are varied with largely range in items and quantities but those of the eastern part, near Sohuksan islands were nearly constant. 4. Styrofoams were composed of 63% among all debris in YS, next paper and cardboard 15%, and wood item, vinyl and plastics each 10%. Therefore, marine debris of YS is revealed that distribution characteristics and composition are very different in each area. These phenomena are concluded that they largely depend on the life styles in land and the utilities of the sea. And of items, styrofoams is dominated by the distribution pattern of YS. Furthermore, surveys are continuously being investigated, and from this it is hoped that a much wider coverage can be achieved, perhaps all sites of the YS and contributed to the finding sources, the stationary area and removal method of debris joined the flow patterns.

• Journal of the Korean Wood Science and Technology
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• v.37 no.3
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• pp.184-191
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• 2009

In the southern part of the Korean Peninsula including Jeju-island, the production amount of domestic cedar has increased gradually. However, their low qualities, expected to be caused by the low density and frequent knots, have restricted their practical utilization as the high value-added products. In this study, it is aimed to look for the new uses of domestic cedar and to examine the applicability for lamination lumbers of structural glued laminated timber (glulam). Above all, machine stress ratings for individual sawn lumbers confirmed that modulus of elasticity (MOE) of cedar lumber was lower than that of other common softwood species in Korea. On the other hand, cedar lumbers have enough stiffness to manufacture the structural glulam in accordance with Korean Industrial Standard (KS). The bonding strength and durability also met the KS limitation. Nevertheless, from the result of bending tests for cedar glulam, it was shown that the modulus of elasticity (MOE) did not meet the KS limitation. Therefore, it was concluded that additional researches were needed for reinforcing the stiffness of cedar glulam.

• Journal of Haehwa Medicine
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• v.26 no.1
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• pp.33-48
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• 2017

Objective : Ten heavenly stems and twelve earthly branches are the important means to understand the orders of changes in heaven and earth. Method : We have so far looked into detailed explanations about twelve earthly branches in Seolmunhaeja, annotations in Seolmun of four major people, and commentaries in Jeongyeokwonui. Result & Conclusion : This can be also applied to the explanations of twelve early branches, as follows. In the $11^{th}$ month of the lunar calendar, the yang energy is finally born amid full of the ying energy. In the $12^{th}$ month, the yang energy prepares to break through the knots of the ying energy and gets ready to come out of the ground. In the first month, three kinds of the yang energy start to become vigorous and active. In the second month, the yang energy gains more force, sprouting various plants on the ground. In the third month, the yang energy arouse further, strengthening and growing plants. In the fourth month, all the yang energy is released, while the ying energy is still hiding. In the fifth month, one ying energy is born amid full of the yang energy, and there are interchanges between the yang energy and the ying energy. In the sixth month, the yang energy is still strong and vigorous, ripening the fruits in the fields. In the seventh month, the yang energy starts to hurt all creation. In the eighth month, the ying energy starts to flourish, and the yang energy starts to decline, diminishing all creation and, however, still ripening grains to be harvested. In the ninth month, one yang energy starts to hide from sight, not working its duty, while five kinds of the ying energy start to annihilate all creation. Finally, in the tenth month, the small yang energy hides to be rebirthed amid the flux and reflux of the ying-yang energy. The creative and unique interpretation of Jeongyeokwonui about twelve earthly branches is worth to be referred. It is definitely beyond the other existing explanations, as it incorporates trigrams and hexagrams from I Ching (Book of Changes) and the five primary substances.

• The Transactions of the Korea Information Processing Society
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• v.3 no.6
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• pp.1397-1406
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• 1996

In this paper, we propose a discrete model of conveyor systems, which is frequently used in flexible manufacturing systems to transfer work-in-process( WIP) between manipulators. In the case where the time required for transferring WIP's between manipulators are greater than that of manufacturing itself, as in many flexible assembly lines, the quantitative model of the transfer systems is needed to analyze the behavior and productivity of the whole manufacturing system. The proposed model is based upon the assumptions that the length of any unit conveyor component is integer multiple of the length of a pallet and hat the transferring speed of the conveyor is constant. Under these assumptions, the observation moments and the length of the conveyor can be quantized. Hence, the state of a conveyor can be represented by two kinds of Boolean variables: one representing the presence of a pallet on each quantize conveyor length and the other representing the mobility of this pallet. The whole conveyor system can be modeling as a network composed of branches and knots based on these two Boolean variables. The proposed modelling method was tested with various conveyor system configurations and showed that the model can be adopted successfully for the simulation of transfer systems and of the piloting of manufacturing processes.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.31 no.5
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• pp.275-282
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• 2018

Using isogeometric analysis(IGA) gives more accurate results for higher order mode in eigenvalue problem than using the finite element method(FEM). This is because the FEM has $C^0$ continuity between elements, whereas IGA guarantee $C^{P-1}$ between elements for p-th order basis functions. In this paper, a mode based reduced model is constructed by using IGA and dynamic behavior analysis is performed using this advantage. Craig-Bampton(CB) method is applied to construct the reduced model. Several numerical examples were performed to compare the eigenvalue analysis results for various order of element basis function by applying the IGA and FEM to simple rod analysis. We have confirmed that numerical error increases in the higher order mode as the continuity between elements decreases in the IGA by allowing internal knots multiplicity. The accuracy of the solution can be improved by using the IGA with high inter-element continuity when high-frequency external force acts on the reduced model for dynamic behavior analysis.

• Journal of the Korean Society of Marine Environment & Safety
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• v.23 no.2
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• pp.139-145
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• 2017

Recently, gusts, typhoon and tsunamis have been occurring more frequently around the world. In such an emergency situation, a moored vessel can be used to predict and analyze other vessel behavior, but if the mooring system is destroyed, marine casualties can occur. Therefore, it is necessary to determine quantitatively whether a vessel should be kept in the harbour or evacuate. In this study, moored ship safety in an exclusive wharf according to swell effects on motion and mooring load have been investigated using numerical simulations. The maximum tension exerted on mooring lines exceeded the Safety Working Load for intervals 12 and 15 seconds. The maximum bollard force also exceeded 35 tons (allowable force) in all evaluation cases. The surge motion criteria result for safe working conditions exceeded 3 meters more than the wave period 12 seconds with a wind speed of 25 knots. As a result, a risk rating matrix (risk category- very high risk, high risk and moderate risk) was developed with reference to major external forces such as wind force, wave height and wave periods to provide criteria for determining the control of capabilities of mooring systems to prevent accidents.

• Journal of the Korean Society of Marine Environment & Safety
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• v.23 no.2
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• pp.208-215
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• 2017

When persistent oil, such as crude oil or Bunker C oil, is spilled at sea, viscosity increases through the weathering process. Equipment that can collect this oil when mixed with floating marine debris is very limited. In this study, devices that can be attached to the outside of existing oil skimmers have been applied to the inside of the main body, to develop an unmanned conveyor belt type floating marine debris and high viscosity oil recovery skimmer, which is composed of a conveyor belt, a sweeper with a forced inflow device, and a collection tank equipped with a buoyant body. The resulting skimmer was operated at a speed of 1.2 knots at a distance of 30 m in a sea area test. It was stable when moving laterally in any direction. An oil recovery performance test was conducted using a portable storage tank, and oil was recovered from a minimum of $7.8k{\ell}/h$ to a maximum of $23.3k{\ell}/h$. Moreover, recovery of $7.7k{\ell}/h$ was obtained in a wave water tank test with floating marine debris such as PET bottles and oil mixed. If the equipment developed in this study was used in the field for oil pollution accidents, it could be expected to contribute to improved response capability. We believe our equipment could be used in further studies to improvement the performance of existing portable oil skimmers.

• Journal of Korean Society of Archives and Records Management
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• v.5 no.2
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• pp.153-165
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• 2005

China is a country with a long history. Chinese culture dates back thousands of years ago. Thousand years of history left the huge quantity of archival heritage, which consists of the memory of China. From tied knots, tortoise shell, bronze, bamboo to paper, film, CD, the mankind's history is kept and continued through the evolution of the documenting media and documenting methods. In the information era, when we are immersed in the sea of information technologies, archivists, as guards of human's memory, have to look for a balance point between new and old, between unchanged and changed. On one hand, archivists should try their best to protect traditional archives in a usable, authentic way in a long term; on the other hand, they must face the challenges posed by electronic record. The information age is a stage of the social development of mankind, the digitalization of archives is an important progress of human history. The report mainly is composed of three parts of the content: first, introduce the preserving situation of Chinese archival heritage ; focus are put on "China archival heritage program" and the construction of "Special archives repository"; second, the process of digitalization of traditional archives; third, the framework of electronic record standard.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.09c
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• pp.72-77
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• 2010

The Incheon Bridge, which was opened to the traffic in October 2009, is an 18.4 km long sea-crossing bridge connecting the Incheon International Airport with the expressway networks around the Seoul metropolitan area by way of Songdo District of Incheon City. This bridge is an integration of several special featured bridges and the major part of the bridge consists of cable-stayed spans. This marine cable-stayed bridge has a main span of 800 m wide to cross the vessel navigation channel in and out of the Incheon Port. In waterways where ship collision is anticipated, bridges shall be designed to resist ship impact forces, and/or, adequately protected by ship impact protection (SIP) systems. For the Incheon Bridge, large diameter circular dolphins as SIP were made at 44 locations of the both side of the main span around the piers of the cable-stayed bridge span. This world's largest dolphin-type SIP system protects the bridge against the collision with 100,000 DWT tanker navigating the channel with speed of 10 knots. Diameter of the dolphin is up to 25 m. Vessel collision risk was assessed by probability based analysis with AASHTO Method-II. The annual frequency of bridge collapse through the risk analysis for 71,370 cases of the impact scenario was less than $0.5{\times}10^{-4}$ and satisfies design requirements. The dolphin is the circular sheet pile structure filled with crushed rock and closed at the top with a robust concrete cap. The structural design was performed with numerical analyses of which constitutional model was verified by the physical model experiment using the geo-centrifugal testing equipment. 3D non-linear finite element models were used to analyze the structural response and energy-dissipating capability of dolphins which were deeply embedded in the seabed. The dolphin structure secures external stability and internal stability for ordinary loads such as wave and current pressure. Considering failure mechanism, stability assessment was performed for the strength limit state and service limit state of the dolphins. The friction angle of the crushed stone as a filling material was reduced to $38^{\circ}$ considering the possibility of contracting behavior as the impact.

• Journal of the Korean Wood Science and Technology
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• v.46 no.3
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• pp.213-220
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• 2018

In order to use Pitch pine (Pinus rigida Miller) as the material of the structural glued laminated timber, the effect of the amount of resin exudation due to storage time after the planning and the knot of the lamina were evaluated on the bonding properties of the glued board with resorcinol resin. For Pitch pine that was dried at high temperature ($120{\sim}95^{\circ}C$) and low temperature ($65{\sim}50^{\circ}C$), the flat sawn(tangential section) showed higher amount of resin exudation than the quarter sawn(radial section). And the low temperature drying wood showed higher resin exudation than the high temperature drying wood. The low and high temperature drying wood showed the highest amount of resin exudation on the 3rd day and 7th day, respectively and they were gradually decreased. However, there were no significant differences from 15 to 90 days. Adhesion performances were low until 2~3 days with high exudation of resin, but there were no significant differences after 15 days. Both high temperature and low temperature drying woods satisfied the Korean standard regardless of the storage time. The adhesive strengths of the laminating parts including knots were higher than those of KS criteria, but the wood failures were not satisfied the KS standard. Adhesive performances according to the laminating combinations (quarter sawn + quarter sawn, flat sawn + flat sawn, quarter sawn + flat sawn) were better than those of KS criteria in all laminating combinations in both high temperature and low temperature drying woods.