• East Asian Economic Review
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• v.21 no.3
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• pp.201-230
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• 2017

This paper studies the long-run behavior of relative price dispersion among cities in Korea with a special emphasis on heterogeneous transitional patterns of price level dynamics. Formal statistical tests indicate considerable evidence for rejecting the null of relative price level convergence among the majority of cities over the sample period of 1985-2015. The analysis of gravity model suggests that the effect of transportation costs on intercity price level differentials is limited, while other socioeconomic factors, such as income, input factor prices, demographic structure, and housing price growth, play key roles in accounting for persistent regional price level disparities. Individual price levels are found to be better explained by a multiple-component model, and the deviations from PPP may be attributed to distinct stochastic common trends that are characterized by income and demographic structure.

• Journal of Institute of Convergence Technology
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• v.4 no.2
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• pp.35-40
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• 2014

Human powered aircraft (HPA) is an airplane that uses only human power for its propulsion. It's development is completely different from conventional aircraft that use fuels as a power source. In the present study, special features for the development of HPA are discussed by studying the design requirements, weight estimation, aerodynamics and propulsion studies, power analysis, and mossion profile design. It is found that the development of the HPA is completely different from conventional aircraft. Mission profile is crucial to the successful flight of the sport HPA when the pilots are changed.

• Proceedings of the Korea Port Economic Association Conference
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• 2007.07a
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• pp.291-312
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• 2007

This paper is designed to look for a specialized strategies by drawing the special features of Busan New Port from both a comparative analysis of major factors of harbor competitiveness and a SWOT analysis of Yangshan Port, one of the biggest competitive ports in Northeast Asia, so that Busan New Port may preoccupy a status as the hub port of the area. The researcher would like to suggest the following measures to make Busan New Port serve as the central port of Northeast Asia on the basis of the findings; Korea should push ahead with creating a railroad transportation linking with Eurasia Contient, secure the amount of goods and resources with the help of the early development of the surrounding complex of the port, make a considerable progress in the level of port service, come up with a differentiation strategies for harbor marketing activities and improve its productivity.

• The KSFM Journal of Fluid Machinery
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• v.13 no.2
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• pp.12-17
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• 2010

A kind of disk-shape boundary layer pump is designed numerically by using a software of computational fluid dynamics, which is widely used for the special purposes such as artificial hearts, bio-fluidics and transportation of oceanic lives, etc. From the numerical simulation with an axisymmetric model, some benchmark problems are tested and compared with experimental results. The performance of disk pump is graphically visualized from the computational results, and converted to the dimensionless parameters. Finally, the obtained numerical data in the present investigation can be used for the baseline for new design to achieve a more efficient disk pump.

• New & Renewable Energy
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• v.10 no.4
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• pp.29-35
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• 2014

Non-used waste heat has recently been paid special attention due to several global warming regulation and energy cost rising. In this study, therefore, thermal energy storage system which uses a solid type heat media has been investigated about the possibility of heat accumulation and heat release for thermal energy storage system. 35kWh of bench-scale thermal storage system was used to investigate the characteristics of the solid type heat media. From the result, it is shown that a solid type heat media should be divided to supply constant heat to the customers' side. It is also shown the flow direction should be considered to reduce temperature difference between top and bottom sides in the thermal storage system.

• Journal of Industrial Technology
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• v.15
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• pp.5-13
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• 1995

Natural gas, which is getting more important as a fuel, should be liquefied and shipped in a special tank. During transportation, a spill of liquefied natural gas(LNG) could occur by a collision or even an accident. As a result, violent explosion called the superheat-limit explosion(SLE) can take place in some cases, unexpectedly. Such explosion may result from the formation of a superheated liquid which has attained the superheat-limit temperature when hot(water) and cold(LNG) liquids come into contact. Natural gas mixtures can be considered as discrete light components plus continuous heavy fractions where several continuous distribution function can be adopted. This work is aiming at prediction of the superheat-limit explosion condition by suing continuous thermodynamics development of algorithm to predict.

• Journal of the Korean Institute of Navigation
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• v.18 no.3
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• pp.11-18
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• 1994

In the present trends at which vessels would be supersizedly designed for adapting special cargoes in order for effective controls of logistics in marine transportation, it brings poor manoeuvrability of ships and makes environmental or economical loss seriously due to accidents of a large scale at sea. International Maritime Organization adopted manoeuvring standards and also recommended manoeuvring booklets for ship operators recently. We attempted to find variation of hydrodynamic derivatives when a bare hull was fitted with propeller and rudder, or propeller only by captive model test in the circulating water channel. On comparing experimental results with theoretical values derived from equations, almost same tenden-cies were found at hull-propeller-rudder and hull-propeller situations. Interactions with rudder displayed well at large drift angles.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.3 no.2
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• pp.251-257
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• 2003

In this paper, we wish to construct a optimal traffic cycle using wire remote control. if police vehicle or ambulance suddenly enter the traffic Intersection, it will increase the traffic accident. In this paper, wireless traffic light use the radio traffic control signal and research about the hardware manufacture to check special detectors on urgency vehicles may safety and rapidly enter traffic intersection. Also, this paper present a traffic signal control conditions that analyzes different traffic intersection flows in cases of saturated flows, where the real traffic volume demand is large and the capacity constraints of bottlenecks have significant effects on the flow patterns. Through computer simulation this wireless traffic light has been proven to be much more safety and efficient than fixed traffic signal light which does not consider emergency vehicles for safety escort.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.25 no.6
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• pp.462-470
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• 2016

The locking load of a conventional manhole depends on the weight of its cover. Locking-type manhole structures with a special locking mechanism were recently developed to prevent accidents such as stolen cover, away cover from a frame. The weight of the manhole structure can be reduced under structural safety because the locking force of a locking-type manhole is greater than the weight of the cover. A light-weight manhole cover is developed in this study by using a finite element stress analysis and the design of experiments. Static stress analysis and fracture experiments are also conducted to analyze the states of the initial product. The optimum light-weight manhole cover considering manufacturing molds is developed and tested. Consequently, the weight was found to reduce by 16%. In addition, the fracture load increased by 38%.

• Journal of Fisheries and Marine Sciences Education
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• v.26 no.1
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• pp.49-58
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• 2014

Variability factors of transship cargo in the container transportation market analysis short term factors. In the past, studies on the factor of variability in container cargo volume have focused on long term volume forecast and increase in investment and competitiveness from strategic perspectives. Unlike previous studies, this paper analyzes factors of variability in transshipment volume rapidly varying in short term and seeks measures. Since it was identified that transshipment volume depends on vessel operation cost and port volume in long term but effectively on special strategies launched by port authorities in short term, the port authority experienced rapid drop in volume should continue to observe strategies of competition ports and to make use of strategies seeking appropriate countermeasures.