• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2011.04a
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• pp.588-593
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• 2011

The Main design parameters of ship HVAC systems are pressure drop and noise analysis of ducts. The Noise prediction for HVAC(Heating, Ventilating and Air Conditioning) systems are normally performed by empirical method suggested by NEBB(National Environmental Balancing Bureau, 1994), but NEBB's method is not suitable for the ship HVAC systems. In this paper, numerical analysis methods are used to develop a noise prediction method for the ship HVAC systems, especially for large ducts. To develop regression formula of attenuation of sound pressure level in large duct, Boundary Element Method(BEM) is used. Using dynamic loss coefficient which is suggested by ASHRAE fitting data base and numerical methods of HVAC noise analysis, integrated HVAC noise analysis of Program is developed. The developed program can present pressure drop and noise analysis of the ship HVAC systems. To verify the accuracy and convenience of the developed program, prediction of HVAC system for Semi-Submersible Drilling RIG is carried out and the results are compared with measurement of noise level during sea trial.

• Journal of the Korean Society of Industry Convergence
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• v.4 no.3
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• pp.295-304
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• 2001

The hydrodynamic impact problem was studied from 1929 to recent. Especially, Impact pressure is important for the design of the ships and offshore structure and spacecrafts, and under weapons. A ship traveling at high speed or in heavy sea has its bow and bottom damaged by high pressure caused by impact with and detachment from the water surface. Considerable impact may also occur when large waves hit the cross member or deck plate of an offshore structure within the splash zone. Many engineering cases require consideration of impact pressure, the movement of objects and change of the flow field. This study was obtained the pressure distribution of a falling body that is deadrise angle $0^{\circ}$ and deadrise angle $5^{\circ}$ upon a water surface by the experiment with the impact machine. The theoretical equation was obtained the air region and the interface and the water region which devide 3 parties between the body and the water surface for an investigation of the complete phenomena. Pressure distributions and histories compare favorably with available experimental data. The numerical results are similar to the experimental results for the impact force type with Fo(1+$cos{\pi}t/tc$).

• Journal of Korea Port Economic Association
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• v.17 no.1
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• pp.91-111
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• 2001

This study was conducted in order to develop inter-local cooperation strategies between the City of Incheon, in Korea, and three provinces in northeastern China. We begin with a description of the history of and prospects for trade between Korea and China, an explanation of the current economic status of Incheon, statistics on the economy, trade and investment trends in the region, and information on the ports of the three Chinese provinces. The following strategies are suggested for inter-local cooperation based on the current circumstances. First, cooperative industrial strategies and economic investment for promoting the mutual concerns and interests of China and Korea were developed. Second, a practical way of utilizing the Incheon Industrial Park located in Dandong, China, was devised to stimulate industrial and investment cooperation. Third, a method of building a network among major ports in Korea and other Northeast Asian port cities was developed. Fourth, an international logistics transportation system that makes connection between sea, land and air easier through logistics standardization was suggested in preparation fur the changing environment of logistics brought about by the opening of the new Incheon International Airport. Fifth, methods of Improving port facilities are suggested. And, finally, the role and necessity of the Incheon City Interchange Center in executing inter-local cooperation strategies is described.

• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.782-787
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• 2008

The Kalina cycle simulation study was carried out for a preliminary design of a geothermal power generation system. The Kalina cycle system can be used for the utilization of a low-temperature heat sources such as geothermal and industrial waste heat that are not hot enough to produce steam. The sea/river water can be considered as a cooling media. A steady-state simulation model was developed to analyze and optimize its performance. The model contains a turbine, a pump, an expansion valve and heat exchangers. The turbine and pump were modelled by an isentropic efficiency, while a condenser, an evaporator and a regenerative heat exchanger were modeled by UA-LMTD method with a counter-flow assumption. The simulation results show that the power generation efficiency over 10% is expected when a heat source and sink inlet temperatures are $100^{\circ}C$ and $10^{\circ}C$ respectively.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.2455-2462
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• 2008

Global warming has become one of the most important social responsibilities. After Kyoto protocol for greenhouse gas reduction by climatic change convention came into effect, developed countries are presenting various policies to reduce greenhouse gas that is produced in transport field. One of those policies is modal shift that change from road freight to sea, inland waterway and railway transportation that is eco-friendly. Because increase of road freight brings about road congestion and accident, logistics cost, air pollution and green house gases. Railways are superior to all other modes of transport in mass transportability, high speed, timeliness, safety and environmental-friendliness, but the railway industry has been pushed behind in competition. In developed country's government actively promoted relevant legislation, policies, and countermeasures known as modal shift policies to shift freight transport from road to large volume mode such as railway and ship. In this paper, we discuss the current situation in modal shift, compare it with cases in other countries EU and Japan, identify problems in Korea, and propose the following ways to enhance competitiveness of rail freight.

• Journal of Integrative Natural Science
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• v.4 no.4
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• pp.298-310
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• 2011

Recently the traffics and transportation hazzards by fog are tremendously Increased. There occurred the greater traffic disaster by Dense Fog of Oct.2006. In this study frequent occurrences of advection fogs centerd over Honam Prov are investigated. Increment of transportation during the Fog period for 1996~2005(decade)are statistically analyzed with Honam Prov.'s fogs. For Honam west coast(Gunsan, Mokpo), inland of Honam(Junju, Gwangju, Suncheon), Honam south coast(Wando, Yepsu), Wind, Dew point, Diff. of air and sea temp. relative humidity are classified between 12 hours before and on time of fog with three Dimensional Analysis System(KLAPS). High frequencies of advection-radiation Fog occurrence in western Coasts except for Suncheon. The application of fog characteristics analyzed by KLAPS for denser fog over the western coast in Fall to Fog prediction and special advisory issues. The advection-radiation fog can occure favorably when the moisture index is less than $2^{\circ}C$, relative humidity is greater than 90%, but the moisture depth is under 1.5 km. In addition when the height of 925 hPa is rising, then fog occurs, but for sinking is disappearing.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.10a
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• pp.165-168
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• 2013

The USA has declared the cyber space as the 5th battlefield following land, sea, air, and space. In contrast to physical wars, in national cyberwarfare differentiation between friend and foe is impossible, and the boundaries between the lines of attack and defense are obscure. Therefore, to perform national cyberwarfare, credibility of all command delivery information performed in the cyber space should be confirmed. In this paper, the authors have determined the commands performed in national cyberwarfare, granted authorized IPv6 in space including the earth, moon and Mars for information credibility, and used LINK joints loaded with stealth functions to secure the credibility of command information.

• Atmosphere
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• v.22 no.4
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• pp.455-464
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• 2012

This study investigates a 12 month-lead predictability of PNU Coupled General Circulation Model (CGCM) V1.1 hindcast, for which an oceanic data assimilated initialization is used to generate ocean initial condition. The CGCM, a participant model of APEC Climate Center (APCC) long-lead multi-model ensemble system, has been initialized at each and every month and performed 12-month-lead hindcast for each month during 1980 to 2011. The 12-month-lead hindcast consisted of 2-5 ensembles and this study verified the ensemble averaged hindcast. As for the sea-surface temperature concerns, it remained high level of confidence especially over the tropical Pacific and the mid-latitude central Pacific with slight declining of temporal correlation coefficients (TCC) as lead month increased. The CGCM revealed trustworthy ENSO prediction skills in most of hindcasts, in particular. For atmospheric variables, like air temperature, precipitation, and geopotential height at 500hPa, reliable prediction results have been shown during entire lead time in most of domain, particularly over the equatorial region. Though the TCCs of hindcasted precipitation are lower than other variables, a skillful precipitation forecasts is also shown over highly variable regions such as ITCZ. This study also revealed that there are seasonal and regional dependencies on predictability for each variable and lead.

• Journal of Environmental Science International
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• v.24 no.6
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• pp.785-792
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• 2015

This study investigates weekday/weekend characteristics of $PM_{10}$ concentration and chemical composition of water-soluble ions in Busan in the spring of 2013. Contribution rate of water-soluble ions to PM10 concentration in weekday/weekend were 41.5% and 38.5%, respectively. Contribution rate of SO_4{^{2-}}$ to total ion mass in weekday/weekend were 30.4% and 33.8%, respectively. Contribution rate of total inorganic water-soluble ions in PM10 in weekday/weekend were 42.2% and 39.1% (mean 41.4%), respectively. $[NO_3{^-}/SO_4{^{2-}}]$ ratio in weekday/weekend were 1.01 and 0.97(mean 0.99), respectively, which indicated that weekday ratio was higher. Contribution rate of sea salts and $Cl^-/Na^+$ ratio in PM10 in weekday/weekend were 8.1% and 7.6%, 0.37% and 0.41%, respectively. This research will help understand chemical composition of water-soluble ions during the weekday/weekend and will be able to measure the contribution level of artificial anthropogenic source on urban air.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.11 no.6
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• pp.201-207
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• 2012

This study was carried out to improve the design of heat exchanger for small marine diesel engine. As air pollutants emitted from small marine diesel engine become international problem, IMO(International Marine Organization) tried to establish severe regulations for NOx reduction. The formation of NOx is affected by cooling system, for instance, such as intercooler, heat exchanger, exhaust manifold, and therefore cooling systems are one of essential parts for design of small marine diesel engine. In this study, heat exchanger for small marine diesel engine was modeled and simulated using CATIA V5R19 and ANSYS FLUENT V.13. Thermal flow simulation for heat exchanger was performed to find the optimal design. As the results, maximum velocity of engine coolant in shell inside was 9.1m/s and it was confirmed that outlet temperature and temperature drop for engine coolant could be calculated by simulating proportional relations of temperature between engine coolant and sea water.