• Journal of the Korean Society of Industry Convergence
• /
• v.24 no.6_2
• /
• pp.899-908
• /
• 2021

It is expected that the global market for vessel repair and remodeling will grow up to the scale of about 25 billion dollars by 2023. Korea's shipbuilding industry is leading the world with its international competitiveness in design and production technology. The actual status of vessel repair industry, however, is poor as there are only two or three companies for vessel repair that can deal with large vessels in the area of Gyeongnam. The reason is that civil complaints are filed severely about environmental problems and environment-related regulations are so strict that it is fairly hard to get governmental approval for the operation of a vessel repair workplace. Domestic vessel repair companies mainly target small- and medium-sized vessels. There are only few workplaces that can carry out regular examination or repair work on large vessels such as LNG vessels, and due to the high price of vessel repair, most of the domestic repair work on large vessels including LNG vessels tends to be snatched by markets in Southeast Asia or China. Despite the tremendous domestic demand of Korea that has established the world's first shipbuilding industry and world's sixth biggest harbor infrastructure, its vessel repair industry can be said to be in very poor condition. In order to vitalize vessel repair industry, this study is aimed to analyze the environmental influence of vessel repair workplaces in Gyeongnam where vessel repair companies are concentrated and suggest standard processes by analyzing vessel repair processes precisely.

• Archives of Plastic Surgery
• /
• v.33 no.2
• /
• pp.187-192
• /
• 2006

The perforator flaps are based on cutaneous vessels which are originated from a main pedicle and penetrate fascia or muscle to reach the skin. The lateral lower leg is one of the most suitable areas for harvesting perforator flaps because a number of perforator vessels exist. The authors applied peroneal perforator flaps in nine patients. Five flaps were reverse island flaps based on peroneal artery and septocutaneous perforator, and four flaps were free flap based on musculocutaneous perforator only. The recipient site was the posterior ankle in three patients, posterior heel in three patients, lateral malleolus, anterolateral ankle, and foot dorsum in one patient each. The flap size ranged from 5 to 12cm long, from 3 to 5cm wide, and the primary closure of the donor site was possible in most cases. All flaps, except for the flap in two patients in the reverse island flap series, survived completely. The peroneal perforator flap is a very thin, pliable flap with minimal donor site morbidity and is suitable for the reconstruction of small and medium sized superficial skin defects. Also, this flap may be considered as an alternative to radial forearm flap or other perforator flaps.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.27 no.7
• /
• pp.1124-1128
• /
• 2021

As regulations of emissions from ships become more stringent, electric propulsion systems have been increasingly used to solve this problem in vessels ranging from large merchant ships to small and medium-sized ships. Methods for improving the efficiency of the electric propulsion system include the improvement of power sources; the use of a system linked to environmentally friendly power sources, such as batteries, fuel cells, and solar power; and the development of hardware and control methodology for rectifiers, power conversion devices, and propulsion motors. The method using a phase-shifting transformer with diodes has been widely used for rectification. Power semiconductor devices with grid connection to an environmentally friendly power source using DC distribution, a variable speed power source, and the application of small and medium-sized electric propulsion systems have been developed. Accordingly, the demand for active front-end (AFE) rectifiers is increasing. In this study, a method using a neural network rather than a conventional proportional-integral controller was proposed to control the AFE rectifier. Tested controller data were used to design a neural network controller trained through MATLAB/Simulink. The neural network controller was applied to a rectification system designed using PSIM software. The results indicated the effectiveness of improving the waveform and power factor DC output stage according to the load variation. The proposed system can be applied as a rectification system for small and medium-sized environmentally friendly ships.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2016.05a
• /
• pp.518-521
• /
• 2016

Korea is surrounded on three sides by the sea, through the maritime transportation accounts for close to 90% share in the total cargo volume. In addition, there are amount of small and medium-sized fishing vessels registered. These days, a number of maritime accidents caused many casualties and having an adverse effect on the marine environment. Therefore, there is a need for a maritime traffic control has been increasing. Information about the ship is divided into AIS information for VTS, Port Management Information System (Port-MIS) operated by the Port and vessels pass (VPASS) that are installed on fishing. However, there is a problem that is not achieved the information exchanged between each other. That is, information on the vessel are stored in diverse inefficient in the management, operation and utilization. This paper discusses the ways to efficiently manage and integrate vessels information for VTS, and proposes the method for implementation and application.

• Journal of Navigation and Port Research
• /
• v.30 no.6 s.112
• /
• pp.465-470
• /
• 2006

Nowadays, vessel's size is tending to bigger, Therefore port facilities are developed according to this trend, which has been shown in the competition of Hub-Port among the main ports such as Port of Busan and Port of Shanghai. However there are the limited number of large containerships more specifically so 70% of the total ships calling at Busan Port are small and medium sized ships which are less than 20,000 ton As a result, it is necessary to consider the handling facilities of these ships which had been disregarded The big size of facilities increases handling cost bemuse of high investment so it is possible for small and medium sized ships to have disadvantages financially and avoid calling. In this paper, we estimate the propriety of utilization of crane and labor according to the size of vessels after analyzing time value cost, reflecting the size of vessels, size and number of crane and labor structure, and container handling cost value.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.22 no.5
• /
• pp.576-582
• /
• 2016

To cope with international regulations, such as Energy Efficiency Design Index (EEDI), Ship Energy Efficiency Management Plan (SEEMP) and so forth, and to enforce limitations on $CO_2$ emissions, green-ship technology to lower fuel consumption has been actively researched, and the development of an energy-saving device (ESD) is being pursued. In order to design an ESD for small and medium-sized domestic vessels, an analysis on flow characteristics has been performed in the present study. Through a model test and numerical analyses, the characteristics of flow around the stern bilge and bulb have been compared to improve wake quality and resistance performance. As a result of these comparisons and analyses, a vertical plate has been adopted,, as a new ESD. Design criteria for the proposed ESD are also suggested. By applying this new ESD, it is expected that the total resistance and average nominal wake can be reduced by 3.04 % and 18.8 %, respectively.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.16 no.2
• /
• pp.692-712
• /
• 2022

Buoys used for Aid to Navigation systems are widely used to guide the sea paths and are powered by batteries, requiring continuous battery replacement. However, since human labor is required to replace the batteries, humans can be exposed to dangerous situation, including even collision with shipping vessels. In addition, Maritime sensors are installed on the route signs, so that these are often damaged by collisions with small and medium-sized ships, resulting in significant financial loss. In order to prevent these accidents, maritime object detection technology is essential to alert ships approaching buoys. Existing studies apply a number of filters to eliminate noise and to detect objects within the sea image. For this process, most studies directly access the pixels and process the images. However, this approach typically takes a long time to process because of its complexity and the requirements of significant amounts of computational power. In an emergent situation, it is important to alarm the vessel's rapid approach to buoys in real time to avoid collisions between vessels and route signs, therefore minimizing computation and speeding up processes are critical operations. Therefore, we propose Fast Connected Component Labeling (FCCL) which can reduce computation to minimize the processing time of filter applications, while maintaining the detection performance of existing methods. The results show that the detection performance of the FCCL is close to 30 FPS - approximately 2-5 times faster, when compared to the existing methods - while the average throughput is the same as existing methods.

• Journal of Advanced Marine Engineering and Technology
• /
• v.40 no.5
• /
• pp.447-452
• /
• 2016

The use of gas as fuel, particularly liquefied natural gas (LNG), has increased in recent years owing to its lower sulfur and particulate emissions compared to fuel oil or marine diesel oil. LNG is a low temperature, volatile fuel with very low flash point. The major challenges of using LNG are related to fuel bunkering, storing, and handling during ship operation. The main components of an LNG fuel system are the bunkering equipment, fuel tanks, vaporizers/heaters, pressure build-up units (PBUs), and gas controlling units. Low-pressure dual-fuel (DF) engines are predominant in small LNG-powered vessels and have been operating in many small- and medium-sized ferries or LNG-fueled generators.(Tamura, K., 2010; Esoy, V., 2011[1][2]) Small ships sailing at coast or offshore rarely have continuous operation at constant engine load in contrast to large ships sailing in the ocean. This is because ship operators need to change the engine load frequently due to various obstacles and narrow channels. Therefore, controlling the overall system performance of a gas supply system during transient operations and decision of bunkering time under a very poor infrastructure condition is crucial. In this study, we analyzed the fuel consumption, the system stability, and the dynamic characteristics in supplying fuel gas for operating conditions with frequent engine load changes using a commercial analysis program. For the model ship, we selected the 'Econuri', Asia's first LNG-powered vessel, which is now in operation at Incheon Port of South Korea.

• Journal of Chest Surgery
• /
• v.3 no.2
• /
• pp.91-106
• /
• 1970

Two groups of left pulmonary-subclavian artery anastomosis were done in 26 adult mongorel dogs. For the first group. the distal end of the subclnvian artery was nnastomosed to the side of the left pulmonary artery, and for the second group, the subclavian end wns anastomosed to the proximal end of the left lower lobe pulmonary artery. Among them, 6 died of bleeding or anesthetic failure during the day of operation, 10 survived 1 to 106 days and the other 10 were sacrificed at various interval. To investigate the relationship between hemodynamic stress and temporal evolution of the pulmonary vascular lesions. the pulmona try and femoral artery pressures, arteriogram and pathohistological specimens were obtained. The following results were obtained. 1. The postoperative pulmonary artery pressures were within normal limits except 2 dogs in the first group, but in nil 12 dogs of the second group, they were in moderate to maked pulmonary hypertension level. 2 After subclavian pulmonary anastomosis, both groups dogs showed increased femond artery pulse pressure. 3. The pulmonary vascular changes were more severe and appeared earlier in the second group dogs compared with the first group.4. The earliest vascular changes appeared in the media of the small muscular arteries and arterioles. 5. Various vascular chaDges were produced in 2 or 3 months. Thereafter, the changes were stationary. 6. Among the first group, two long-term servivors (No. 705 & 713) which had normal pulmonary artery pressure under the anesthesia, also showed various vascular changes as other pulmonary hypertensive dogs. 7. In the early stage medial hypertrophy. interruptio~l of elastic lamellae were found in the small muscular arteries and arterioles, which were followed by intimal proliferation and thrombosis. These findings may suggest some evidences of trauma to the vessels. 8. Pulmonary arteriograms showed irregularity of the intima of the large and medium sized arteries, abrupt ending of some of the small arteries and narrowing of the anastomosis.

• Archives of Plastic Surgery
• /
• v.34 no.6
• /
• pp.759-764
• /
• 2007

Purpose: Various types of flaps, with their own advantages and disadvantages, have been described for reconstruction of soft tissue defect with exposure of tendons, bones, or joints in the hand or foot. Local flaps with random vascularity have a limitation by their length. Free flaps are time-consuming procedure that may require the sacrifice of some major vessels. The ideal flap for covering soft tissue defects of the hand or foot must provide subcutaneous tissue that tendons can glide through which, supply enough subcutaneous tissue for cover of vital neural, bony, vascular and joint structures, and it has to be aesthetically pleasing. The adipofascial flap fulfills these criteria. It allows immediate or early closure of difficult wound of hand and foot in an easy way, and is especially indicated for small to medium-sized defects. Methods: From October 2005 to December 2006, seven cases underwent this procedure to reconstruct soft tissue defect on hand or foot. Results: All flaps survived completely, and no complications were observed. Conclusion: The adipofascial flap is a convenient flap for coverage of soft tissue with exposure of vital structure in the hand or foot, and provide several advantages, as following; easy and safe, short operating time, one stage procedure, thinness and good pliability of the flap, preservation of the major vascular pedicles, skin preservation at the donor site, thus preserve the shape of the limb and minimize donor site scar.