• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.10 no.3
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• pp.343-347
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• 1998

The objective of this study is to manufacture the low temperature waterless container that is compact and low cost for a live fish transportation. Using the low temperature water container, it makes observations on the optimal conditions such as the amount of dissolved oxygen, total ammonia and nitrite in seawater for determining the survival rate of live fish in short and long-term transportation. Using a sole as a live fish, the temperatures of $0^{\circ}C$, 3$^{\circ}C$, 5$^{\circ}C$, 7$^{\circ}C$, 15$^{\circ}C$ were controled for there effects. The results of this investigation show that as the seawater temperature increased, the amount of oxygen decreased and there was a low temperature shock below 3$^{\circ}C$. It was observed that the fish was died with 30$m\ell/\ell$of ammonia. The optimal temperature is about 5$^{\circ}C$ for live fish transportation to maintain best survival rate.

• Journal of Korean Society for Quality Management
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• v.24 no.4
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• pp.124-140
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• 1996

This study aims to deveop a methodology for measuring the level of service quality in the air transportation. To measure the level of service quality, the approach taken here deals with not only the facility factors but also qualitative factors such as comfort and convenience as the influencing elements for service quality. The contents of this study can be summarized as follows: (1) For the systematic developement and management of air service, service factors of the air transportation are classified by AHP(analytic hierarchy process). (2) In computing the weight of service factors, a pairwise comparison method in AHP is used. (3) This study will suggest a method of measuring the competitive level of air service, and a result of an empirical study appling the method developed.

• Journal of Aerospace System Engineering
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• v.6 no.3
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• pp.19-23
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• 2012

"The FAA's Next Generation Air Transportation System" is a comprehensive overhaul of U.S National Airspace System to make air travel more convenient and dependable, while ensuring the flight is as safe, secure and hassle-free as possible. At its most basic level, NextGen represents an evolution from a ground-based system of air traffic control to a satellite-based system of air traffic management. This evolution is vital to meeting future demand, and to avoiding gridlock in the sky and at U.S airports. NextGen will open worldwide's skies to continued growth and increased safety while reducing aviation's environmental impact.

• 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 Environmental Health Sciences
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• v.48 no.1
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• pp.44-51
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• 2022

Background: Air pollution is increasing together with industrialization and urbanization. In order to reduce air pollution, public transportation is recommended rather than private cars, and the number of passengers using public transportation is increasing accordingly. This study observes the concentration of indoor pollutants in city buses over time. Through this means, we intend to suggest a plan to manage the indoor air quality in city buses. Objectives: The concentration of indoor pollution in public transportation was investigated from April 2021 to January 2022. Based on this, we evaluated the exposure to indoor pollutants. Methods: Six city bus lines in an industrial city were selected for the research, and indoor pollution was measured through IoT (Internet of Things)-based sensor-type measuring devices. The concentration of pollutants was measured every minute, and statistical data were constructed based on the measurement results. Results: In all the city buses studied, the average concentration of pollutants were below the guidelines. However, some measurement results showed cases of exceeding the guidelines. As a result of the analysis by time zone, there were more cases in which pollutants exceeded the standard value during rush hour compared to at other times. A risk assessment for PM₁₀ was performed by evaluating the excess mortality risk from exposure and the risk from inhalation exposure. Conclusions: All measured indoor pollutants in the city buses did not exceed the guidelines. Also, the risk assessment results were found to be within the level of safety. However, if a city bus is used for a long time, there is a possibility that there may be an impact on the human body due to inhalation exposure, so additional management is required.

• Journal of the Korean Society for Precision Engineering
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• v.33 no.7
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• pp.535-540
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• 2016

The braking device in railway vehicles decelerates or stops the train by dissipating the thermal energy converted from kinetic energy into the air. Therefore, the brake system is crucial for safety. In this paper, we performed a study on an electromechanical brake actuator using an electrical motor as an alternative to pneumatic air cylinders to reduce the idle running time in braking, which subsequently increases braking distance, and to ensure reliable response characteristics. Especially, to analyze the response characteristics of the electromechanical brake actuator, we measure the delay time, response time and power consumption compared to the air cylinder. It is confirmed that the electromechanical brake actuator can reduce reaction time by 0.1 seconds (Braking Action) and 0.46 seconds (Brake Release) compared to the air cylinder.

• Journal of the Korean Geographical Society
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• v.35 no.1
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• pp.53-75
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• 2000

본 연구는 사천공항에 있어서 항공 화물수송의 시.공간적 특성과 공항의 배후지를 파악하는 것을 목적으로 한다. 국내선 화물수송량에 의해 제4계층에 속하는 사천공항의 탑재 화물수송은 그 배후지가 남서부 경남지역으로 핵심 배후지와 주변 배후지로 구성되는 공간구조를 나타내며, 주로 어묵과 화훼를 탑재하고 감규을 간재하는 기능을 가지고, 탑재화물 중심의 편하현상을 나타내고 있다. 그리고 계절별(6.12월).요인별.편별 항공 화물수송량의 시간적 차이가 존재한다는 것을 알 수 있다.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.21 no.5
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• pp.1-14
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• 2022

In this study, in order to analyze the preference for UAM of public transportation users following the introduction of urban air transportation(UAM), A preference consciousness(SP) survey was conducted on 840 users of Incheon public transportation using the Incheon International Airport-Incheon Gil Hospital route, which is the urban air traffic(UAM) demonstration route section. In addition, the means selection model was estimated based on the results of conducting a preference consciousness (SP) survey. As a result of analyzing the time value for travel using the established means selection model, it was found to be 56,428 won/hour, As a result of verifying the elasticity of travel cost (won), in-vehicle time (minutes), and out-of-vehicle time (minutes) in the model, the effect on the urban air traffic (UAM) share in this model was found that travel cost (won), in-vehicle time (minutes), and out-of-vehicle time (minutes) were in order, and the effect was greater when the travel cost (won) decreased than when it increased.

• Journal of Korean Society of Transportation
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• v.11 no.2
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• pp.45-62
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• 1993

The major objective of this study is to analyze the differences between operating costs of teleconferencing and alternative transportation modes for the conference in major compaines. Alternative transportation modes include road, rail, and air transportation mode. A case study is conducted using the data gathered for Pohang Steel Coperations. The main results are: (1) the operating cost of the teleconferencing is cheaper than operating cost of transportation modes when the number of teleconferencing are over 12 frequencs, and the number of person are over 15. Results reveal that teleconferencing turns out to be effective means of conference. (2) the amount of differences of operating costs on teleconsferencing and transportation modes gets higher according to the time elapsed. In particular, when teleconferencing cost is compared to operating cost of road transportation, it is found that the cost saving of 2.75 billion won in year 2001 can be realized.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.1951-1957
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• 2010

Study of Lunar exploration is progressed and manned lunar exploration is planned. In order to explore in Lunar, we need habitat to stay for a long time and system that mine, classify and transport materials. Lunar has dust that is very light-tiny. That is on the air for a long time so there are problems to adject transportation system such as vehicle. However, it can solve the problem to use pipe transportation system. This transportation system help materials move continually and is more effective than other transportation system such as train or vehicle. For those positive points, some experts studied about tube transportation systems. I introduce these system and find out factors that can be used in Lunar regolith transportation system. I suggest Lunar regolith transportation system, using the factors.