• Proceedings of the Korea Concrete Institute Conference
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• 2006.05a
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• pp.566-569
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• 2006

The purpose of this study is to develop digital air meter used pressure sensor for measurement of air content in freshly mixed concrete by pressure method. The digital air meter can enhanced measurement accuracy and uniformity of air content in freshly concretes, according to use of pressure sensor and measuring process automation. Finally, the digital air meter in this study is improved reproducibility and reliability of measurement compared with analog air meter.

• Architectural research
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• v.1 no.1
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• pp.47-53
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• 1999

An interesting of desktop air-conditioning system is the Personal Environmental Module(PEM) System. The PEM system allows the occupant to choose the desired temperature, air volume and direction of the discharged air. In this study, the measurements on the age of air and the air change effectiveness, using the tracer gas method, are carried out to analyze the ventilation performance for provision of fresh air near the breathing zone by the PEM. The relations between the PEM for optimal control and other factors related to indoor air quality, and the ventilation for the PEM are examined. Also, three different supply diffuser types(desktop, floor and ceiling) are compared in view of their ability to distribute supply air to the workstation breathing zone. The desktop diffuser type could deliver air directly to the occupants breathing zone with a high degree of effectiveness. The minimum local age of air was measured in the breathing zone, which is directly supplied with air from the PEM diffusers, and the measured local air change effectiveness of the desktop diffuser in the breathing zone was about 1.13 to 1.23 times greater than that of the ceiling and floor diffusers. When the minimum outside air change rate as specified using ASHRAE Standard 62R is supplied with a desktop diffuser type, the volume of outside air can be reduced 13 to 23%, resulting in a commensurate in ventilation energy use.

• Tribology and Lubricants
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• v.25 no.5
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• pp.292-297
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• 2009

Air foil thrust bearings are the critical components available on high-efficiency turbomachinery which need an ability to endure the large axial force. Air foil bearings are self-acting hydrodynamic bearings that use ambient air as their lubricant. Since the air is squeezed by the edge of compliance-surface of bearing, hydrodynamic force is generated. In this study, we measured the air film thickness and obtained the minimum film thickness experimentally. To increase the maximum load capacity, compliance of sub-structure was controlled. From numerical analyses, it is seen that, if the air film thickness is distributed more uniformly by variable compliance, the thrust bearings can take more axial load.

• International Journal of Air-Conditioning and Refrigeration
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• v.13 no.1
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• pp.31-43
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• 2005

The new HVAC system is developed to lower the conveyance energy and building height using IAV(Increasing Air Volume) technique. IAV units which are equipped in each zone carry out air-conditioning and supply fresh air by induction of outdoor air in main duct. The design program which decides size of OAHU and IAV unit according to air conditioning load and fresh air demand of each zone is presented. The control system is developed to operate efficiently HVAC system and IAV unit, so that individual zone operation and well-deal with partial load and IAQ problem are possible. The new system is investigated in model building and makes more profit in conveyance energy. size of air conditioning facilities room and building height than VAV system. But in construction cost it is worse by about 15 percentage.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.44 no.3
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• pp.64-72
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• 2021

Manned-unmanned teaming can be a very promising air-to-air combat tactic since it can maximize the advantage of combining human insight with the robustness of the machine. The rapid advances in artificial intelligence and autonomous control technology will speed up the development of manned-unmanned teaming air-to-air combat system. In this paper, we introduce a manned-unmanned teaming air-to-air combat tactic which is composed of a manned aircraft and an UAV. In this tactic, a manned aircraft equipped with radar is functioning both as a sensor to detect the hostile aircraft and as a controller to direct the UAV to engage the hostile aircraft. The UAV equipped with missiles is functioning as an actor to engage the hostile aircraft. We also developed a combat scenario of executing this tactic where the manned-unmanned teaming is engaging a hostile aircraft. The hostile aircraft is equipped with both missiles and radar. To demonstrate the efficiency of the tactic, we run the simulation of the scenario of the tactic. Using the simulation, we found the optimal formation and maneuver for the manned-unmanned teaming where the manned-unmanned teaming can survive while the hostile aircraft is shot-downed. The result of this study can provide an insight to how manned aircraft can collaborate with UAV to carry out air-to-air combat missions.

• Particle and aerosol research
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• v.13 no.2
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• pp.43-52
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• 2017

Policy direction for the management of air quality in Korea has been on the reduction of the average concentrations of the criteria air pollutants such as sulfur dioxide and fine particles. However, recently, risk based management of air pollutants becomes an important issue. In this study, to develop an effective air quality management policy direction in Korea, (1) the fourth Multiple Air Toxics Exposure Study (MATES IV) carried out in the South Coast Air Quality Management District (SQAQMD) in the USA is reviewed and (2) the results are compared with in these in Seoul and (3) policy directions are suggested. It was found that (1) systematic integrated study comprising of measurement, modeling, emission inventory estimation, and risk assessment was essential to estimate the health risk of air pollutants reliably, (2) cancer risk of diesel particle was dominant over other air pollutants, and (3) health risk based emissions were different from amount based emissions. It was suggested that (1) reducing the exposure from hot spots might important to reduce health risk from air pollutants and (2) an integrated air quality management administration system is important for the efficient management of air pollution.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.18 no.12
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• pp.999-1006
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• 2006

A study of temperature profiles in mixing zone of AHU (air handling unit) can contribute greatly to enhance performance of AHU system, so the study on the temperature distribution between RA (return air) and OA (outdoor air) is important to analyze the mixing characteristics in a mixing zone of AHU. Accordingly, the temperature profiles during RA (return air) and OA (outdoor air) supply process into mixing zone of AHU with an air mixer are studied experimentally. The effect of air mixer, OA temperature and RA/OA flow rate are studied in detail. In this study, the results show that the mixing efficiency is all high for installed the air mixer. The more OA temperature increase and OA flow rate decrease, the more mixing efficiency is high.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• v.40
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• pp.97-144
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• 2008

The purpose of this paper is to review the text of national legislation relating to the carrier's liability in respect of the carriage of passengers, baggage and cargo by air in major states such as United Kingdom, Germany, France, Canada, Russia and China, and to compare the air carrier's liability under the national legislations of above states with them under the Warsaw System relating to the international carriage by air. Also this paper reviews the text of the draft legislation relating to the carrier's liability in respect of the carriage by air in Korea. The Warsaw Convention for the Unification of Certain Rules Relating to International Carriage was adopted in 1929. In 1999, the ICAO adopted the Montreal Convention for the Unification of Certain Rules for International Carriage by Air vastly modernizing the unification of private air law. The Montreal Convention replaced the instruments of the “Warsaw System”, and came into force on 4 November 2003. The Montreal Convention is not only an international convention. It has also exercised a considerable influence on national legislation. A the Convention, or certain of its principles, with the object of regulating their national air transport. The main feature of the liability regime of the air carrier under the Montreal Convention is the two-tier liability system for death or injury of the passenger with strict liability up to 100,000 SDR and presumptive liability with a reversed burden of proof without any limit above that threshold. The principles of the liability of the air carrier under the Montreal Convention have been adopted into national legislations by the United Kingdom, Germany, France, Canada, Russia and China. Now the Ministry of Justice of Korea is proceeding to make a new national legislation relating to the liability of the air carrier in respect of the carriage by air. The draft legislation of the Part VI the Carriage by Air of the Commercial Code of Korea has adopted the main principles of the liability of the air carrier under the Montreal Convention. In conclusion, the national legislation relating to the liability of the air carrier in Korea will contribute to settle efficiently the dispute on the carrier's liability in respect of the carriage of passengers, baggage and cargo by air.

• Journal of Korea Trade
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• v.26 no.3
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• pp.117-136
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• 2022

Purpose - Port is vital for international trade accounting for approximately 80% of world cargo transportation in the global trade sector. Air pollutants emitted owing to the related industry interfaces developed around the port spread throughout the dense population region can have harmful effects on the nearby residents. This study aims to analyze high-concentration diffusion pattern by air pollutants, considering the main management periods by air pollutants. Design/methodology - Employing the concentration criteria per main air pollutant, the analyses of concentration change patterns per air pollutant, wind characteristics that directly affected the air pollutant diffusion, distribution types per air pollutant, and high-concentration diffusion patterns by season according to time changes were conducted. Findings - The substances that caused harmful levels of air pollution in the hinterland living zone of the Busan New Port were PM_10, PM_2.5, and NO_2. Furthermore, the intensive management periods were as follows: For PM_10, 24-h (spring), 12:00-16:00 (summer), 12:00-16:00 (summer), 20:00-12:00 (fall), and 24:00-20:00 (winter), and for PM_2.5, 24-h (all four seasons), and for NO_2, 23:00-04:00 (spring), 23:00-08:00 (summer), and 20:00-08:00 (fall), and 23:00-04:00 (winter). Originality/value - Research finding indicates that regular monitoring and countermeasures to reduce air pollution for each air pollutant makes it possible to achieve effective air quality control in the port and hinterland living zones.

• International Journal of Air-Conditioning and Refrigeration
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• v.12 no.2
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• pp.61-69
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• 2004

In this study, on-site performance test of an air source heat pump which has a rated capacity of 10 RT is carried out. Since indoor and outdoor air conditions can not be controlled to satisfy the standard test conditions, experiments are done with the inlet air conditions as they exist. To estimate the performance of the heat pump for other conditions, the heat pump is modeled with a small number of characteristic parameters. The values of the parameters are determined from the few measurements measured on-site during steady operation. A simulation program is developed to calculate cooling capacity and power consumption at any other arbitrary operating conditions. The simulation results are in good agreement with the experiment. This study provides a method of an on-site performance diagnosis of an air source heat pump.