• Journal of the Korean Society for Aviation and Aeronautics
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• v.27 no.4
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• pp.44-51
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• 2019

This study analyzes the trade patterns that occur between Korea and ASEAN countries through air transport, one of Korea's trade transport methods. In order to understand the detailed characteristics of the air transport sector, the dependent variables were analyzed by dividing them into amount and weight. As a result, the amount of exports, imports, and trade was proportional to GDP per capita representing income level, and inversely proportional to GDP representing national economic power. In terms of air transport weight, exports, imports and trade were all proportional to GDP representing economic power and inversely proportional to GDP per capita representing income levels. In addition, the national area acted as a factor to reduce the trade volume, and the number of airports and inland countries did not show any significant results.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.9 no.2
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• pp.111-117
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• 1980

The optimum methods of transport of fresh mackerel caught at korean coast and neighboring sea were investigated. The quality of mackerel after 3 day-stored with ice showed that the freshness were still kept. The temperature fluctuation of mackerel during transport with ice from Busan to Seoul indicated below $5^{\circ}C$, recommended by I.I.R. Heat loss of iced mackerel in transit was calculated and converted into ice weight in case of cargo truck and insulated truck. It was assumed that the semi-dressed mackerels were more effective and economic than the round ones during transport.

• Korea Trade Review
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• v.47 no.4
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• pp.35-52
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• 2022

Air transport is at the core of global economic growth. There is a close relationship between the flow of regional elements and the growth of the regional economy. It is easy to misestimate the impact of airports on the regional economy without considering spatial spillover effects. This study attempted to establish an asymmetric economic geographical weight matrix by applying the Spatial Durbin Model with cargo volume and passenger numbers as indicators. The influence of spillover effects on the regional economy, including direct spillover effects and indirect spillover effects are studied. The results revealed that passenger numbers and cargo volume have significant positive spillover effects on the regional economy. The driving effect of the airport on the regional economy was considered from a wider space scope. This study contributes to the scientific evaluation of the aviation economy.

• Structural Engineering and Mechanics
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• v.71 no.3
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• pp.283-290
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• 2019

In global competition manufacturing companies have to produce modern, new constructions from advanced materials in order to increase competitiveness. The aim of my research was to develop a new composite cellular plate structure, which can be primarily used for structural elements of road, rail, water and air transport vehicles (e.g. vehicle bodies, ship floors). The new structure is novel and innovative, because all materials of the components of the newly developed structure are composites (laminated Carbon Fiber Reinforced Plastic (CFRP) deck plates with pultruded Glass Fiber Reinforced Plastic (GFRP) stiffeners), furthermore combines the characteristics of sandwich and cellular plate structures. The material of the structure is much more advantageous than traditional steel materials, due mainly to its low density, resulting in weight savings, causing lower fuel consumption and less environmental damage. In the study the optimal construction of a given geometry of a structural element of a road truck trailer body was defined by single- and multi-objective optimization (minimal cost and weight). During the single-objective optimization the Flexible Tolerance Optimization method, while during the multi-objective optimization the Particle Swarm Optimization method were used. Seven design constraints were considered: maximum deflection of the structure, buckling of the composite plates, buckling of the stiffeners, stress in the composite plates, stress in the stiffeners, eigenfrequency of the structure, size constraint for design variables. It was confirmed that the developed structure can be used principally as structural elements of transport vehicles and unit load devices (containers) and can be applied also in building construction.

• Nuclear Engineering and Technology
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• v.52 no.8
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• pp.1817-1825
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• 2020

Background: Cosmic ray-induced particles can lead to failure of semiconductors packaged for export during air transport. This work performed MCNP 6.2 simulations to optimize shielding against neutrons and protons induced by cosmic radiation Methods and materials: The energy spectra of protons and neutrons by incident angle at the flight altitude were determined using atmospheric cuboid model. Various candidates for the shielding materials and the geometry of the Unit Load Device Container were evaluated to determine the conditions that allow optimal shielding at all sides of the container. Results: It was found that neutrons and protons, at the flight altitude, generally travel with a downward trajectory especially for the particles with high energy. This indicated that the largest number of particles struck the top of the container. Furthermore, the simulation results showed that, among the materials tested, borated polyethylene and stainless steel were the most optimal shielding materials. The optimal shielding structure was also determined with the weight limit of the container in consideration. Conclusions: Under the determined optimal shielding conditions, a significantly reduced number of neutrons and protons reach the contents inside the container, which ultimately reduces the possibility of semiconductor failure during air transport.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.21 no.12
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• pp.2196-2208
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• 1997

In this work, a magnetic levitation (maglev) system is developed to transport a wafer between semiconductor fabrication process modules in clean rooms to take advantages of eliminating particle and oil contamination that normally exist in conventional transport systems due to contact motion of mechanical components. A main feature of the maglev system developed in this work is that a controller and power supplying part are not mounted on the moving carrier but on the stationary track, which is defined a controller-free carrier, to reduce carrier's weight. Iron-core electromagnets and irons are used for levitation, and air-core electromagnets and permanent magnets are used for stabilization. Analysis, design, and modeling of the magnetically levitated transport system are presented. The performance of the maglev system is experimentally demonstrated.

• International journal of advanced smart convergence
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• v.11 no.2
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• pp.153-162
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• 2022

The impact of the information technology industry on economic development is becoming increasingly important. In this study, we take China's provincial-level regions from 2015 to 2020 as the research object, comprehensively evaluates the level of their information technology systems by the entropy weight method, and then measures the coupling coordination relationship between the information technology system and the economic development system by the coupling coordination degree model. As a result, we found that the income of the information technology industry, the investment of talents and science research have the most important influence on the level of the information technology system. During the research period, with increasing values, the coupling degree of the two systems was at a high level. Affected by development strategies, diffusion effects and industrial relocation, the coupling degree in the central and western regions has shown a rapid growth trend. The coordination degree of the two systems is relatively low, and 83.9% of the provinces are in the medium-low coordination stage. The information technology industry has obviously promoted economic development. Besides, relevant policies should be introduced to effectively support and guide the high-quality development of the information technology industry and promote the high-level coordinated development of the two systems.

• Journal of Navigation and Port Research
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• v.36 no.10
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• pp.905-910
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• 2012

In early 1990s, the Sea & Air Transport Cargoes (SATC) was increased annually with more than 50% rate due to the rising trade between Korea and China. However, after that, the increasing rate of the SATC was slowdown from the late 1990s, furthermore, recently it became sluggish and declined. This phenomenon is totally different compared to the skyrocketing trade volumes between two countries. In this respect, to forecast the SATC, draw out the factors for activation, and calculate the weight of priority of these factors are urgently needed. To achieve the research objectives, the ARIMA and Fuzzy-AHP were used as research methodology. The estimated volume of SATC using the data from year 2007 to 2012 on the ARIMA model, will be reached approximately 33,000 tons in year 2015. In the mean time, For drawing out and weighing the activation factors for SATC, the Fuzzy-AHP was adopted. As a result, 'Sea & Air transportation-related information system policies' is the most important factor among the principle criteria, and 'the construction of consolidation logistics center' is the most important factor among the 12 sub-principle criteria.

• Journal of the Korean GEO-environmental Society
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• v.16 no.2
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• pp.15-25
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• 2015

As the physical and mechanical properties of lightweight air-mixed soil change in the procedure of transportation of mix truck, it is necessary to assure whether the properties during construction satisfy those in design. In this study, variations of properties of mixed soil after transportation by mix truck are proved by field test. Lightweight air-mixed soil used field test the unit weight of $9.0{\pm}1.0kN/m^3$, the flow value of $190{\pm}20mm$ was produced. To analyze variations of properties of mixed soil the unit weight and flow value of the sample before and after transport was measured unconfined compressive strength tests were performed. Mixing time was 19~175 minutes diversified. As the test results, it is known that the density, the flow value and the unconfined compressive strength of lightweight air-mixed soil change by transportation, but these values satisfy the specifications of material of air-mixed soil. After transportation the average value of the unit weight and flow value change in the flow of the $(+)0.10kN/m^3$, 4.8 mm respectively, the average change in the unit weight and the flow value due to the mixing time was constant. And unconfined compressive strength of 28-day specimen increases from 20 to $150kN/m^2$. But, these values do not have some clear relationship with the transportation time within 175 minutes which is longest test time. Consequently, Within 175 minutes the changes of properties by transportation are too small to show some problems in the construction field.

• Journal of Korean Society for Atmospheric Environment
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• v.29 no.1
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• pp.1-9
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• 2013

Hazardous Air Pollutants (HAPs) are difficult to measure, analyze and assess for risk because of low ambient concentrations and varieties. Types of HAPs are Volatile organic compounds (VOCs), Polycyclic aromatic hydrocarbon (PAHs) and Aldehydes. HAP emissions from vehicles are a contributor to serious adverse health effects in urban areas. In this study, hazardous air pollutant emissions from road transport vehicles by Non-methane volatile organic compounds (NMVOC) weight fraction and PAHs emission factors are estimated in 2008. The top-five-most hazardous air pollutant emissions were estimated to toluene 864.3 ton/yr, acrolein 690.6 ton/yr, acetaldehyde 554.5 ton/yr, formaldehyde 498.7 ton/yr, propionaldehyde 421.6 ton/yr in 2008. The results for a cancer and non-cancer risk assessment of HAPs emissions show that the major cancer driver is formaldehyde and the non-cancer driver is acrolein.