• Proceedings of the Korea Society for Simulation Conference
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• 2001.10a
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• pp.468-476
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• 2001

The ROK TRANSCOM is trying to establish a concrete wartime sealift operation plan. But there are many problems to be solved for setting up the plan. The most serious problem is to procure war materiel to be shipped in U.S.A and next one is to determine the number of sealift assets and to allocate them. The process of sealift operation can be described as follows. Before the order of vessel mobilization, all vessels appointed for activation would be scattered in worldwide in the state of Beaded or unloaded. After the order of vessel mobilization, vessels would go to SPGE(seaport of embarkation) to load war materiel. Some loaded ships should offload the commercial cargo to the near port as soon as they are activated, before they would go to SPOE. All vessels would load procured materiel in SPOE and then go to SPOD(seaport of debarkation). They would offload war materiel in SPOD and then go back to SPOE to load war materiel again. We will simulate this process using ARENA(1), evaluate the sealift capability of ROK and find omit problems of the sealift plan. This model ultimately evaluates the sealift capability and provides planners with critical information far establishing and correcting the plan. This study can also provide military planners with a flexible and accessible decision support tool to provide advance planning under a variety of conditions on the sealift capability. The military planner is expected to make use of this model as a standard for establishing effective and concrete sealift operation in the near future. We can conclude how procurement capability significantly affects the result of sealift operation through this model. We could decide the appropriate levee of sealift asset such as the number of vessels and the number of available berth. So we could allocate effectively the resources for completing the sealift operation within the TGT(Target) time.

• Journal of Veterinary Clinics
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• v.18 no.4
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• pp.324-328
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• 2001

This study was performed to evaluate the effects of $AS_2O_3$ upon antiangiogenesis in rat cornea, to examine it\`s possible application as an anticancer drug and to provide basic data for further studies of antiangiogenetic mechanism of $AS_2O_3$ . Angiogenesis was induced by cornea micropocket assay, as previously described. Sixteen of forty-eight eyes of Sprague-Dawley rats were randomly assigned to one of three groups, namely, only a bFGF group(control group), and a group treated by $AS_2O_3$ ($AS_2O_3$ group). After pellet implantation, we measured the number of new vessels, vessel length and clock hour of neovascularization, and area of neovascularization was determined using a mathematical formula. New vessels growing began at day 3, number of vessels in $AS_2O_3$ group were significantly more less than those in control group (p<0.05). The length of vessels of $AS_2O_3$ group was significantly shorter than that of control group after day 3(p<0.05). The clock hours of all group were slowly increased at all days but $AS_2O_3$ group was inhibited more than control group. Neovascularization areas of $AS_2O_3$ group were more significantly inhibited than those of control group (p<0.05). This study showed that $AS_2O_3$ had powerful antiangiogenetic effects and it would be useful in the choice of anticancer drug.

• Archives of Plastic Surgery
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• v.49 no.1
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• pp.121-126
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• 2022

Background Although they may not replace standard training methods that use surgical microscopes, smartphones equipped with high-resolution screens and high-definition cameras are an attractive alternative for practicing microsurgical skills. They are ubiquitous, simple to operate, and inexpensive. This study compared anastomoses of chicken femoral vessels using a smartphone camera versus a standard operative microscope. Methods Forty anastomoses of non-living chicken femoral vessels were divided into four groups. A resident and an experienced microsurgeon performed anastomoses of femoral chicken vessels with 8-0 and 10-0 sutures, using a smartphone camera and a surgical microscope. The time to complete the anastomosis and the number of anastomosis errors were compared using the Mann-Whitney U test. Results The time taken to perform an anastomosis by the experienced microsurgeon was significantly longer when using the smartphone (median: 32.5 minutes vs. 20 minutes, P<0.001). The resident completed the anastomoses with both types of equipment without a significant difference in the operative times. When using a smartphone, the operation times were not significantly different between the resident and the experienced microsurgeon (P=0.238). The resident showed non-significant differences in operation time and the number of errors when using a smartphone or an operative microscope (P=1.000 and P=0.065, respectively). Conclusions Microsurgical practice with non-living chicken femoral vessels can be performed with a smartphone, though it can take longer than with an operative microscope for experienced microsurgeons. The resident may also experience frustration and tend to make more anastomosis errors when using a smartphone versus an operative microscope.

• Journal of Chest Surgery
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• v.48 no.1
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• pp.13-24
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• 2015

Background: Controversy persists regarding the use of coronary endarterectomy (CE) in patients with severe coronary artery disease. We compared the comorbidities and perioperative characteristics of patients undergoing coronary artery bypass grafting (CABG) with and without CE. Methods: This study was performed in two private hospitals in Shiraz, Iran from May 2010 to December 2011 on 967 patients who underwent CABG without CE and 84 patients who underwent CABG with CE (the CE+ group). After follow-up at $9.66{\pm}3.65$ months post-surgery, 28 patients from the CE+ group underwent angiography to evaluate the patency of grafts and native coronary vessels. Results: Patients in the CE+ group had a more prevalent history of diabetes (48% vs. 36%) and number of diseased vessels ($2.88{\pm}0.39$ vs. $2.70{\pm}0.85$). The overall hospital mortality was 1.8%, and no significant difference was observed between the two groups. In the 28 patients who underwent reangiography, 113 vessels were bypassed and 29 endarterectomies were performed, mostly on the left anterior descending artery (12 endarterectomies) and the right coronary artery (8 endarterectomies). In the endarterectomized vessels, a 66% patency rate was found in both the grafts and the native vessels. The native coronary vessels were more likely to be patent when the left internal mammary artery was used as a conduit than when a saphenous vein bypass graft was used. Conclusion: The lack of a significant difference in postoperative complications in patients who underwent CABG with or without CE may indicate that CE does not expose patients to a higher risk of complications. Since most of the endarterectomized vessels were shown to be patent during the follow-up period, we propose that endarterectomy is a viable option for patients with severely diseased vessels.

• International Journal of Naval Architecture and Ocean Engineering
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• v.4 no.4
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• pp.403-411
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• 2012

This study presents the nano-sized particle emission characteristics from a small turbocharged common rail diesel engine applicable to prime and auxiliary machines on marine vessels. The experiments were conducted under dynamic engine operating conditions, such as steady-state, cold start, and transient conditions. The particle number and size distributions were analyzed with a high resolution PM analyzer. The diesel oxidation catalyst (DOC) had an insignificant effect on the reduction in particle number, but particle number emissions were drastically reduced by 3 to 4 orders of magnitude downstream of the diesel particulate filter (DPF) at various steady conditions. Under high speed and load conditions, the particle filtering efficiency was decreased by the partial combustion of trapped particles inside the DPF because of the high exhaust temperature caused by the increased particle number concentration. Retarded fuel injection timing and higher EGR rates led to increased particle number emissions. As the temperature inside the DPF increased from $25^{\circ}C$ to $300^{\circ}C$, the peak particle number level was reduced by 70% compared to cold start conditions. High levels of nucleation mode particle generation were found in the deceleration phases during the transient tests.

• International Journal of Ocean System Engineering
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• v.3 no.4
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• pp.175-187
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• 2013

Moonpools are vertical wells in a floating body used onboard many types of vessels like Exploration and drilling vessels, Production barges, Cable-laying vessels, Rock dumping vessels, Research and offshore support vessels. Moonpool gives passage to underwater activities for different types of ships as per their mission requirements. It is observed that inside a moonpool considerable relative motions may occur, depending on shape, depth of the moonpool and on the frequency range of the waves to which the ship is exposed. The vessel responses are entirely different in zero and non-zero Froude number. Former situation is paid attention in this study as the mission requirement of the platform is to be in the particular location for long period of operation. It is well known that there are two modes of responses depending on the shape of the moonpool viz., piston mode for square shape and sloshing mode for rectangular shapes with different aspect ratios of opening like 1:1.5 and 1:2 ratios. Circular shaped moonpool is also tested for measuring the responses. The vessel moored using heavy lines are modelled and tested in the wave basin. The pretensions of the lines are varied by altering the touchdown points and the dynamic tensions on the lines are measured. The different modes of oscillations of water column are measured using wave gauge and the vessel response at a particular situation is determined. RAOs calculated for various situations provide better insight to the designer.

• Journal of the Korean Society of Marine Environment & Safety
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• v.23 no.3
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• pp.231-241
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• 2017

The purpose of this study was to analyze traffic safety assessments for fishing vessels near the southwest offshore wind farm. This study applied a collision model for safety assessment. It also involved a spatiotemporal analysis of vessels engaged in fishing to identify fishing hotspots around the offshore wind farm. This study used data from fishing vessel location transmission devices gathered over 1 year in 2014. As a result, in September, when the average number of vessels engaged in fishing is high, 62 ships were operating in fishing section 184-6 and 55 ships in section 184-6. In addition, in fishing sections 184-8 and 192-2, where an offshore wind farm was located, there were 55 and 38 ships operating, respectively. As the recovery period for a seaway near wind farm turbines is 55 years, it was determined that safety measures are required in order to reduce collision frequency while allowing fishing vessels to navigate through offshore wind farms. Meanwhile, the return period of Seaway B between the groups of generators considered was 184 years. A safety zone for offshore wind farms should be installed covering a distance of at least 0.3 NM from the boundary of turbines. Then, the collision return period was derived to be close to 100 years. Through this traffic safety assessment, it has been concluded that such measures would help prevent marine accidents.

• Journal of Biomedical Engineering Research
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• v.16 no.1
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• pp.1-8
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• 1995

A variety of experiments of endothelial cell seeding onto artificial vessels have been performed. To improve endothelialization, one or two components of the extracellular matrix (ECM) have been used as an underlying matrix. In this study, the whole ECM excreted from fibroblasts was used as an underlying matrix. Fetal human fibroblasts were cultured on a polyurethane (PU) sheet. After a conflu; ence was attained, the cytoskeleton and the nuclei of the fibroblast were destroyed using Triton-X. Mitomycin, or irradiation. Omental microvascular endothelial cells from adult human were seeded onto various substrates. After 12 days in culture, the cells were counted. It was observed that the ECM treated by irradiation had the highest cell number. In addition, the cells on this substrate exhibited the most typical endothelial cell morphology. For preliminary animal experiments the PU vessels (inner diameter, 1.5mm) coated with ECM were implanted in the infrarena] abdominal aorta of rat. After the vessels had been implanted for 5 weeks, it was found that the surface of the PU vessels was completely covered with endothelia] cells. In conclusion, we can state that the fibroblast-derived whole ECM makes a better underlying substrate for the endothelialization of small diameter artificial vessels.

• Journal of Fisheries and Marine Sciences Education
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• v.27 no.3
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• pp.725-734
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• 2015

In contemporary society, many fishery industries face a serious problem of having an insufficient number of junior ship officers and engineers. Even though many fishery high schools in Korea made significant effort to produce many talented junior officers and engineers, but after graduation, the students are reluctant to get a job on the fishing vessels. Furthermore, Korean government also invested a large amount of money to train students for ocean-going and costal & near-ocean fishing vessels. However, despite the government's great effort on the training program and education, only a few students wish to work on the fishing vessels. In this article, the author tried to find answers for various questions such as what are the factors that the student prefer, where the student to want to get a job in fishery industries, and how student feel about working at fishing vessels. Furthermore, the author also analyzed the differences between high school student group and Korea Institute of Maritime and Fisheries Technology(KIMFT) student group about occupational orientation by utilizing SPSS statistical program. Additionally, the author surveyed the current onboard status of job position of the high school and KIMFT alumni. This study's results and data will be used for aiding further stimulation and advertisement of job position in fishing vessels and continued daily lives on board.

• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.3
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• pp.313-319
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• 2019

As vessels become larger and competition between ports intensifies, there has been an increase in the number of cases where vessels that exceed the available berths are berthed at the pier. Therefore, there has been an increase in the number of cases in which the bow or stern of a ship is projected and moored. The risk of overhanging berthing is that mooring safety can be compromised because it is not possible to connect the bow and stern mooring line to the ship properly. In addition, collision accidents may occur between moving vessels if the view of a vessel moving in the port is obstructed. Therefore, in this study, the simulation of mooring safety was performed according to the overhanging range in Piers No. 6 and 7 in Ulsan's main port to propose the overhanging limit and operational standards according to each ship. As a result of the assessment, 30,000 DWT bulkers are able to overhang up to 0.75B, and 50,000 DWT bulkers can overhang up to 0.50B. The results of this study are expected to be used as basic data for setting the allowable overhang limit, as well as clear usage criteria for safe unloading operations.