• Journal of Korean Society of Coastal and Ocean Engineers
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• v.26 no.4
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• pp.253-266
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• 2014

The ECOM3D is used to study the circulation characteristics and density current from the Sumjin River runoff in the Kwangyang Estuarine System, South Sea, Korea. Annual mean value of $120m^3/s$ was imposed from the Sumjin River. The numerical model results in terms of tidal height, current and salinity field show satisfactory with skill scores over 90%. The current velocity showed the range of 1~2.5 m/s during flood and ebb phases. In particular, very strong flow occur in the narrow Channels of Noryang, Daebang and Changson exceeding over 2.0 m/s. The tidal residual currents in the various locations in the Kwangyang Estuary showed the range of 1~21 cm/s, The density-driven current through the Yeosu and Noryang Channels are about 12 cm/s and 4 cm/s, respectively. The current path through the Yeosu Channel is deflected toward west Bank. Based on budget analysis of the volume flux, the volume flux through the Yeosu Channel and the Noryang Channel were estimated to be 97.4 and $22.1m^3/s$ accounting for the 81.5% and 18.5% of total flux, respectively.

• Journal of the Korean Electrochemical Society
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• v.10 no.4
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• pp.245-251
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• 2007

The performance of fuel cell is enhanced with increasing reaction surface. Narrow flow channels in flow plate cause increased pumping power. Therefore it is very important to consider the pressure drops in the flow channel of fuel cell. Previous research for pressure drop for micro channel of fuel cell was focused on effects of various configuration of flow channel without electrochemical reaction. It is very important to know pressure loss of micro flow channel with electrochemical reaction because fluid density in micro channel is changed due to chemical reaction. In this paper, it is investigated that the pressure drops in micro channel of various geometries at anode and cathode with electrochemical reaction and compared them to friction coefficient (fRe), velocity, pressure losses for corresponding non reacting flow channel. The results show that friction factors for cold flow channel could be used for parallel and bended flow channel for flow channel design of fuel cell. In the other hand, pressure drop for serpentine flow channel is the lowest among flow channels due to bypass flow across gas diffusion layer under reacting flow condition although its pressure drop is highest for cold flow condition.

• The Korean Journal of Community Living Science
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• v.11 no.2
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• pp.29-42
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• 2000

It has long been believed that European clothing style has been developed independently without the Eastern influence. This deductive assumption has limited the understanding about the contents of Eastern clothing style, and there has only been limited studies on the Eastern influence on the European clothing. The lack of understanding and interest made the traditional Eastern influence on the European clothing. The lack of understanding and interest made the traditional Eastern clothing to be considered as merely exotic and relatively unimportant. Therefore, a thorough study and understanding of the contents of the Eastern clothing style and its influence on the western world is very much needed. The objective of this study is to see how the clothing of the Islamic Osman Turk had influenced Europe during the Gothic and Renaissance period and to find the relationship between the development of the East and West clothing style. This study also has the purpose of re-evaluating the importance of the Eastern culture in the present multi-cultural global era of the 21 st century. The most typical clothing of the Osman Turk was kaftan and other traditional clothing included narrow pants and head dress. Through trade, war and other channels, the Turkish influence changed the styles and colors of previous European fashion that can be characterized by the simple designs of tunic and mantle into a dynamic dress culture. Cotehardie adopted the styles of the Turkish kaftan. The new weaving techniques enabled new clothing such as Pourpoint, Houpplelande made of brocade and velvet with elegant patterns come into European fashion. Also, head dresses, which before were not used except for religious reasons were widely worn. As such, Turkish fashion gave significant influence on the development of European clothing style.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.23 no.2
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• pp.47-53
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• 1987

Many studies are conducted to evaluate the risk of maneuvering ships in the congested harbours and narrow channels. These studies are very important for the prevention of sea traffic accidents in those sea areas. In this paper, the author carried out a series of observations on sea traffic condition of the vessels entering and leaving the harbour of CHUNG MU, in order to evaluate the risk of grounding, the margin and burden of route keeping maneuver of vessels proceeding along the fairway of this harbour. The results obtained are as follows: 1. The grounding risk indices for the east bound and west bound vessels at the middle part and western part of the fairway were higher than those of them at the eastern part. 2. The margin of route keeping maneuver in the fairway appeared to be the highest at the western part of the fairway for the east bound vessels, and the highest at the middle part for the west bound vessels, but the lowest at the western entrance for both of them. 3. The burden of route keeping maneuver in the fairway appeared to be the highest at the western part of the fairway for both of the east bound and west bound vessels, but the lowest at the eastern part for both of them. 4. The influence of maneuvering indices T' on the grounding risk indices appeared to be larger than that of maneuvering indices K' on them.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.23 no.2
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• pp.1-1
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• 1987

Many studies are conducted to evaluate the risk of maneuvering ships in the congested harbours and narrow channels. These studies are very important for the prevention of sea traffic accidents in those sea areas. In this paper, the author carried out a series of observations on sea traffic condition of the vessels entering and leaving the harbour of CHUNG MU, in order to evaluate the risk of grounding, the margin and burden of route keeping maneuver of vessels proceeding along the fairway of this harbour. The results obtained are as follows: 1. The grounding risk indices for the east bound and west bound vessels at the middle part and western part of the fairway were higher than those of them at the eastern part. 2. The margin of route keeping maneuver in the fairway appeared to be the highest at the western part of the fairway for the east bound vessels, and the highest at the middle part for the west bound vessels, but the lowest at the western entrance for both of them. 3. The burden of route keeping maneuver in the fairway appeared to be the highest at the western part of the fairway for both of the east bound and west bound vessels, but the lowest at the eastern part for both of them. 4. The influence of maneuvering indices T' on the grounding risk indices appeared to be larger than that of maneuvering indices K' on them.

• Journal of Ocean Engineering and Technology
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• v.26 no.4
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• pp.37-41
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• 2012

Due to global warming, the need to secure alternative resources has become more important nationally. Because of the very strong current on the west coast, with a tidal range of up to 10 m, there are many suitable sites for the application of TCP (tidal current power) in Korea. In the southwest region, a strong current is created in the narrow channels between the numerous islands. A rotor is an essential component that can convert tidal current energy into rotational energy to generate electricity. The design optimization of a rotor is very important to maximize the power production. The performance of a rotor can be determined using various parameters, including the number of blades, shape, sectional size, diameter, etc. There are many offshore jetties and piers with high current velocities. Thus, a VAT (vertical axis turbine) system, which can generate power regardless of flow direction changes, could be effectively applied to cylindrical structures. A VAT system could give an advantage to a caisson-type breakwater because it allows water to circulate well. This paper introduces a multi-layer vertical axis tidal current power system. A Savonius turbine was designed, and a performance analysis was carried out using CFD. A physical model was also demonstrated in CWC, and the results are compared with CFD.

• Journal of the Korean Institute of Navigation
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• v.9 no.1
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• pp.1-40
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• 1985

The transport of cargoes carried by coastal and ocean-going vessels has increased with the rapid growth of the Korean economy these days. This increase of the sea-borne cargoes has made the Korean coastal traffic so congested that this can be a cause of large pollution as well as great marine casualties such as loss of human lives and properties. Marine casualties generally result from the complicated interaction of natural and human factors; the former being the topographic, marine traffic volume and meteorological conditions, and the latter being the quality of seafares. In this paper, the authors analyse the trend of marine casualties in the Korean coastal and clear up the cause of accidents and examine closely the mutual relations among sea accidents, weather conditions, and marine traffic volume. These accidents are classified into several patterns on hte point of view of ship's size, ship's type and ship's age and its characteristics of each pattern are described in detail. Also, the authors estimate the amount of economical losses resulting from marine casualties which are classified into the accident patterns, and clarify the effects of those losses on B/B(Balance Sheet) and P/L(Profit & Loss) of Korean shipping companies and Korean national economy. The analyzed results of marine casualties are summarized as follows: 1) The average number of sea accidents is 248 cases per year with the loss of 107 persons during last 13 years. 2) Collision is the top of causes of sea accidents (approx. 36.4%), shipwreck the second (approx. 20.3%), agroung the third rank (approx. 18.2%). 3) The ship's number under 1, 000G/T is approx. 74% of total ship's number of accidents. 4) 80% of total number of marine accidents is taken plact at the coastal waters. (involved ports & narrow channels) 5) Marine casualties are occur likely to in the night, the winter and the summer. 6) The average amount of economical losses is approx. 18.5 billion won. (approx. 0.14% of GNP) 7) Shipwreck is the top of the amount of economical losses (approx. 60.4%), collision the second (aprox. 24.5%), aground the third (approx. 9.9%). 8) The amount of economical losses is approx. 5.24% of gross capital of shipping co., 1.24% of shipping revenue, 1.38% of shipping total income in 1983.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.48 no.4
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• pp.24-31
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• 2011

A high data rate Medical Implant Communications Service (MICS) transmitter for implantable medical devices (IMD) is proposed. An orthogonal frequency division multiplexing (OFDM)-based multicarrier scheme is used to overcome the data rate limitation caused by the narrow bandwidth of 300 kHz. The proposed transmitter utilizes multiple MICS channels simultaneously, supporting increased data rate. To satisfy the MICS regulation, various schemes are applied including optimized subcarrier allocation and inverse fast Fourier transform (IFFT) architecture, and additional sidelobe suppression technique. Simulation results show that the proposed transmitter can support a maximum data rate of 4.86 Mbps, which is more than ten times faster than the previous systems.

• Journal of Korean Foot and Ankle Society
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• v.3 no.1
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• pp.40-48
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• 1999

The neck of the talus is its most vulnerable and fragile segment, because of narrow diameter, devoid of hyaline padding and honeycombed internally by vascular channels etc. Talar neck fractures comprise 50% of all major to the talus. The majority occurs as a result of high-energy injuries, such as motor vehicle accidents or fall from a height. Anatomically, talar surface is covered mainly with articular cartilage and blood supply to the talus is very poor. So, complications, such as non-union, avascular necrosis and post traumatic arthritis, are frequent. The authors reviewed fourteen cases of talar neck fractures treated in our clinics from Jan. 1992 to Mar. 1997, and average follow-up period was over 15 months. The results obtained were as follows; 1. Patients' average age was 31.2 years. 2. The most common cause was traffic accident(9/14, 64%), and hyperdorsiflexion injury of the ankle was common mechanism of the fractures. 3. According to the modified Hawkins classification, type I was four cases, type II was nine cases, type III was one case and type IV was no case. 4. Hawkins sign of subcortical radiolucency was found in 64% (9/14) of the fractures. 5. Avascular necrosis was occurred in 21% (3/14) of the fractures(in two cases of type II fractures, and in one of type III). 6. According to the Hawkins criteria, four cases in type I, five in type II were an excellent result. Two cases, one in type II and one in type III were good result, and two in type II were fair. One in type II was poor result.

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