• Journal of the Computational Structural Engineering Institute of Korea
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• v.29 no.2
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• pp.123-130
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• 2016

With the development of fast construction mode in shipbuilding market, the demand on accuracy management of hull is becoming higher and higher in shipbuilding industry. In order to enhance production efficiency and reduce manufacturing cycle time in shipbuilding industry, it is important for shipyards to have the accuracy of ship components evaluated efficiently during the whole manufacturing cycle time. In accurate shipbuilding process, block accuracy is the key part, which has significant meaning in shortening the period of shipbuilding process, decreasing cost and improving the quality of ship. The key of block accuracy control is to create a integrate block accuracy controlling system, which makes great sense in implementing comprehensive accuracy controlling, increasing block accuracy, standardization of proceeding of accuracy controlling, realizing "zero-defect transferring" and advancing non-allowance shipbuilding. Generally, managers of accuracy control measure the vital points at section surface of block by using the heavy total station, which is inconvenient and time-consuming for measurement of vital points. In this paper, a new measurement method based on point clouds technique has been proposed. This method is to measure the 3D coordinates values of vital points at section surface of block by using 3D scanner, and then compare the measured point with design point based on ICP algorithm which has an allowable error check process that makes sure that whether or not the error between design point and measured point is within the margin of error.

• Journal of the Korean Society of Marine Environment & Safety
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• v.18 no.3
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• pp.273-278
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• 2012

The use of Al alloys instead of fiber-reinforced plastic(FRP) in ship construction has increased because of the advantages of Al-alloy ships, including high speed, increased load capacity, and ease of recycling. This paper describes the effects of probe diameter on the optimum friction stir welding conditions of 5456-H116 alloy for leisure ship, measured by a tensile test. In friction stir welding using a probe diameter of 5 mm under various travel and rotation speed conditions, the best performance was achieved with a travel speed of 61 mm/min. Using a probe diameter of 6 mm, rotation speeds of 170-210 rpm, and a travel speed of 15 mm/min produced a rough surface and voids because of insufficient heat input produced by the low rotation speed. At 500-800 rpm, chips were observed, although there were no voids, and the weld surface was excellent. However, at 1100-2500 rpm, many chips were produced due to excessive heat input. Heat effects were very evident on the bottom. For a travel speed of 15 mm/min, heat input caused by friction increased as the rotation speed increased. The mechanical characteristics were degraded by accelerated softening due to increasing heat input.

• Journal of the Society of Naval Architects of Korea
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• v.38 no.1
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• pp.99-107
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• 2001

Manufacture of fishing vessel is needed the effective material for light, strength, fire and corrosion of water in order to improve durability by high-speed and fishing. These fishing vessel can be divided into FRP and AI alloys fishing vessel. FRP fishing vessel is light and effective for strength but highly ignited and susceptible to heat during the manufacturing ship by-produce noxious component for human. In the case of a scrapped ship, it cause environmental pollution. On the other hand, aluminum is a material in return for FRP and has merit of high-strength and lightness. It's more heat proof and durable than FRP and superior to prevent from corrosion. Al alloys fishing vessel development is rising as an urgent matter. But, al alloy has some defect of bad weldability, welding transformation, cracks and overcost of construction. Therefore this study is to develop the new welding joint shape solving aluminum defects and mechanical behavior. First of all, strength was compared and reviewed by analysis of plate, stiffen plate, new model simplified by using plate theory. On the base of this result, plate and new model of temperature distribution, weld residual stress and strength of tensile, compressive force were compared and reviewed by finite element computer program has been developed to deal with heat conduction and thermal elasto plastic problem. Also, new model is proved application possibility and excellent mechanic by strength comparison is established to tensile testing result.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.4
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• pp.546-551
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• 2020

Generally, surface vessels have many compartments for operation and living quarters, and each compartment is an important space for the ship's survivability. During ship construction, a compartment leak test is necessary and is carried out on each vessel. However, the current test method is in doubt when looking at the actual test results. The reason is that only one pressure gauge is used for the measurement to check the air, so an uncomprehended phenomenon is detected during group compartment leak tests. From this point of view, an improved test device and method are needed. In this study, a multi-channel data acquisition device with multiple pressure sensors is proposed to detect each compartment's pressure variation or pressure drop. This test is a more confidential compartment leak test than the current method, and the test device can show real-time pressure detection values of each of the pressure sensors, which are installed in each compartment, including unmanned space.

• Nuclear Engineering and Technology
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• v.42 no.5
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• pp.582-589
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• 2010

As a part of the back-end fuel cycle, transportation of spent nuclear fuel (SNF) from nuclear power plants (NPPs) to a fuel storage facility is very important in establishing a nuclear fuel cycle. In Korea, the accumulated amount of SNF in the NPP pools is troublesome since the temporary storage facilities at these NPP pools are expected to be full of SNF within ten years. Therefore, Korea cannot help but plan for the construction of an interim storage facility to solve this problem in the near future. Especially, a decision on several factors, such as where the interim storage facility should be located, how many casks a transport ship can carry at a time and how many casks are initially required, affect the configuration of the transportation system. In order to analyze the various possible candidate scenarios, we assumed four cases for the interim storage facility location, three cases for the load capacity that a transport ship can carry and two cases for the total amount of casks used for transportation. First, this study considered the currently accumulated amount of SNF in Korea, and the amount of SNF generated from NPPs until all NPPs are shut down. Then, how much SNF per year must be transported from the NPPs to an interim storage facility was calculated during an assumed transportation period. Second, 24 candidate transportation scenarios were constructed by a combination of the decision factors. To construct viable yearly transportation schedules for the selected 24 scenarios, we created a spreadsheet program named TranScenario, which was developed by using MS EXCEL. TranScenario can help schedulers input shipping routes and allocate transportation casks. Also, TranScenario provides information on the cask distribution in the NPPs and in the interim storage facility automatically, by displaying it in real time according to the shipping routes, cask types and cask numbers that the user generates. Once a yearly transportation schedule is established, TranScenario provides some statistical information, such as the voyage time, the availability of the interim storage facility, the number of transported casks sent from the NPPs, and the number of transported casks received at the interim storage facility. By using this information, users can verify and validate a yearly transportation schedule. In this way, the 24 candidate scenarios could be constructed easily. Finally, these 24 scenarios were compared in terms of their operation cost.

• Bulletin of the Society of Naval Architects of Korea
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• v.6 no.1
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• pp.25-34
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• 1969

From viewpoints of over-all ship economy the straight framed V-bottom hull forms with chines are considered to be attractive even for usual commercial vessels, because increments of resistance over that of round hull forms, if any, can be well compensated with reduction in construction cost.[1] To investigate the influences of both prismatic coefficient and chine elevation on resistance performance, three models of straight-framed V-bottom hull forms which are similar to Prof. C. Ridgely-Nevitt's W-18, W-8, and W-20[2],[3] in size and hull form coefficients were tested at the SNU Ship Model Towing Tank for resistance measurements. They are of Cp=0.60, 0.65 and 0.70 and of ${\Delta}/(0.01L)^3=300$. Influence of variation of chine elevation on resistance performance were observed with the test results obtained at normal condition, and at the trimed by the stern by 2% and 4% of $L_{bp}$ at normal condition under same displacement. The hull form characteristics are shown in Table 1, and in Fig. 1, 2, 3, 4 and 5. The test results are shown in Fig 8, 9 and 10 in the form of Cr vs. $V/\sqrt{L}$ curves taking Cp as a parameter for normal condition, trim by the stern in 2% and 4% $L_{bp}$ at normal condition , respectively. Cr vs. $V/\sqrt{L}$ curves taking trim condition as a parameter are also shown in Fig 11, 12 and 13 for Cp=0.60 and 0.70, respectively. The best and the worst trim condition at given $V/\sqrt{L}$ in viewpoint of Cr are plotted for each Cp-value as shown in Fig 14, 15 and 16. From the above results the following conclusions are derived: (1) In general, the resistance performance of the straight-framed V-bottom hull forms are not inferior to those of round hull forms. At a certain range of $V/\sqrt{L}$ the former gives less resistance than the latter. (2) Regarding influences of Cp on Cr, it is observed that, at $V/\sqrt{L}$ less than about 0.925, the greater Cp-value gives the more increment of Cr, and that, at $V/\sqrt{L}$ greater than about 0.925 the smaller Cp-value gives the more increment of Cr. It is also noteworthy that the model of Cp=0.70 has remarkable hump on Cr vs. $V/\sqrt{L}$ curve between $V/\sqrt{L}=0.80$ and 0.90. (3) For higher speed within the test range, the chine elevation having the steeper slope around bow and the easier slope around amidship and stern, refered to watering, give the better results in resistance performance. (4) Assuming the chine elevations adopted for the tested models were not of the best, we would expect further improvement of resistance performance for such form. Hence, a systematic study on chine elevation is very disirable to prepare design data of general purpose for the such hull forms.

• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.1
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• pp.1-8
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• 2019

In December 2017, many collision accidents of small vessels, such as those between oil refineries and fishing boats, occurred near Yeonghung-do in Incheon. In order to prevent marine casualties from small vessels, the government is striving to improve the safety capabilities of ship operators by strengthening education and improving the working environment. They are providing education and refining training regulations for fishermen operating vessels under 5 tons. However, the situation includes certain vulnerabilities. In this study, we propose a collision prevention algorithm for small vessels using the Wireless Access in Vehicular Environments (WAVE) communication system, which is a new communication technique to prevent collisions with small ships. The collision avoidance algorithm used is based on DCPA/TCPA. Research analyses, simulation experiments and questionnaires have been conducted to define the criteria of DCPA/TCPA. As a result, the standard for DCPA was $8(L_a+L_b)$ and for TCPA was 2.5 min. Three different accident cases were selected, and this algorithm was applied to confirm alarm responses at certain times. This algorithm can provide information to the operators of small ships in advance to help them recognize potential collision situations.

• Journal of Environmental Health Sciences
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• v.49 no.4
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• pp.190-200
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• 2023

Background: Gunsan has been constantly affected by pollutants generated by the Saemangeum development and the construction industry since the completion of the Saemangeum seawall on April 27, 2010. However, there are limitations to its study, such as taking into consideration weather conditions, geographical factors, and foreign inflows. Objectives: In this study, we compared the Existing-CAPSS emissions of Gunsan with Recalculated-CAPSS emissions data to analyze the differences in emissions characteristics by year (2016~2019). Methods: Using Existing data on CAPSS emissions (2016~2019) and Recalculated-CAPSS emissions (2016~2019) for Gunsan, which were Recalculated following the improvement of emissions calculations for 2020, we organized CO, NO_X, SO_X, PM₁₀, VOC_S, and NH₃ emissions by substance and investigated the differences and characteristics of the Recalculated emissions by year. Results: For Re-CO and Re-PM₁₀, the emission characteristics of CO were examined as energy industry combustion and PM₁₀ emission characteristics were examined as ship cargo from non-road transportation sources, as ship leisure sources were excluded from non-road transportation source emissions. Conclusions: Comparing the emissions of Existing-CAPSS and Recalculated-CAPSS in Gunsan, the emissions of Recalculated-CAPSS by substance decreased by 39.76% for CO, 9.98% for PM₁₀, 5.53% for VOC_S, and 9.24% for NH₃, while Re-NO_X increased by 2.86% and Re-SO_X increased by 1.97%. On the other hand, when comparing the emissions characteristics of Existing-CAPSS and Recalculated-CAPSS in Gunsan, Jeonju, and Iksan, the emission characteristics of Re-NO_X, Re-SO_X, Re-VOC_S and Re-NH₃ were similar to those of Ex-NO_X, Ex-SO_X, Ex-VOC_S, and Ex-NH₃. As such, Gunsan, Iksan, and Jeonju, showed differences in the comparison of different emission characteristics due to the geographical characteristics of the region (population, area, topography, weather factors) and the characteristics of the industrial complex (metal, petrochemical).

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.5B
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• pp.547-558
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• 2008

With the advent of super cargo ship due to the explosive increase in the amount of cargo shipped via seas, some mega ports are under construction in South Korea, to accommodate the super cargo ship, and some of them already enter their final phase. To sustain the harbor tranquility, mega ports usually comprise huge vertical type breakwaters which are intrinsically vulnerable to the attack of long waves. In this rationale, we present the chamber type breakwater with a circular curtain wall - Eco-breaker 2, to alleviate the reflection of long waves and numerically investigate the hydraulic characteristics of Eco-breaker 2. As a wave driver, we use the Navier-Stokes eq., the most robust wave driver, using SPH (Smoothed Particle Hydrodynamics) and LES (Large Eddy Simulation). For the verification of numerical results, we also carried out hydraulic model test. It is shown that Eco-breaker 2 can effectively alleviate the reflection of long waves with its inherited large organized eddies encompassing the water chamber and some region off the curtain wall of varying size. It is also shown that the scope and strength of large organized eddies strongly depends on the incident wave period, and the reflection coefficient can be lowered to 0.18 by tuning the size of water chamber such that resident time at the chamber is just short of the half period of incident waves. Based on these results, we present the specification of Eco-breaker 2 to boost its use on the development of water environment friendly harbor worldwide.

• Journal of Navigation and Port Research
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• v.31 no.3 s.119
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• pp.205-212
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• 2007

Due to the construction of Incheon Grand Bridge, there is driven a necessity for rearranging the function of Inner Port with the development of Outer South Port. In this paper, I'd like to simulate the port operation levels of Lock Gate in Inner Port with estimating the traffic volumes of 2011 and 2015, which will reveal the Demurrage Cost and the Accumulation Cost of Freight in Inner Port. Finally I will evaluate the economic movement effects of the container ship's calling from Inner port to South Port/Outer South Port from 2011 to 2015. The results are as followings ; (1) The average utilization of Lock Gates are reduced by $7\sim8$ percentage point. (2) The mean queueing value are saved by 25 percentage point. (3) The Demurrage Cost and the Accumulation Cost of Freight except Lock Gate charges and the Benefit of Routeing Reduction are saved about 800 million Won annually.