• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.20 no.12
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• pp.820-824
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• 2008

Electret filter media are used in general ventilation filters, disposable respirators, vehicle cabin filters, vacuum cleaners and room air cleaners. There are basic mechanisms of interception, inertial impaction, diffusion, gravitational settling, electrostatic attraction by which an aerosol particle can be deposited onto a fiber in a filter. The ability of fine particle removal strongly depends on the electrostatic forces between particles and polarized fibers. Thus, the stability of the fiber polarization is a major factor in the reliability of electret filters. In this study, the electret filter is made by electrospinning process using Polystyrene which is dissolved by 5 : 5 of Tetrahydrofuran (THF) and Dimethylformamide (DMF). Also the electrical properties and the filtration performances of electrospun filter media are Quantitatively investigated. Electrical properties of electrospun filters have been studied on surface charge potential and surface charge density. Also the filtration performance of the electret filters are evaluated on collection efficiency. The surface charge potential and the surface charge density of electrospun PS filters are increased with increasing applied voltage and saturated at 30 kV of applied voltage. Also collection efficiency of electro spun filters is increased with increasing surface charge potential and surface charge density. But the surface charge potential is decreased by natural decay and it causes deterioration of particle collection efficiency.

• Journal of the Korean Society for Railway
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• v.10 no.6
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• pp.723-729
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• 2007

The Ministry of Environment established a guide line in December 2006, "Indoor Air Quality Management guidelines in Public Facilities." As the items of the guideline, $CO_2$ (Carbon dioxide) and PM10 (particulate matter) is shown to Level 1 and 2. Therefore trains and subways are included. There are a lot of tunnels by the lay of mountains on KTX (Korean Train Express) service. HVAC (Heating Ventilating and Air-conditioning)-pressurization equipment on KTX is various functioning flaps blocking outside pressure waves. At that time, the fresh air is blocked by flap operation and the air is circulated by return air. In this study, we measured the time series of $CO_2$ and PM10 concentrations in the KTX passenger cabin during the train service of Gyongbu line (Seoul-Busan) and Honan line (Yongsan-Mokpo) from July 2006. Also, analyzed the air quality by operation of KTX HVAC-pressurization equipment in tunnel passing point. As a result, PM10 concentration was totally lower than the regulation values. However, $CO_2$ was highly correlated with several tunnels, such as Oksan-Otan, Godeung-Hyudae and Gaechak-Iijik tunnel. but, the indoor air quality of KTX train have been proved satisfy the recommendation the Ministry of Environment guidelines.

• The KSFM Journal of Fluid Machinery
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• v.19 no.1
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• pp.18-23
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• 2016

A HVAC(Heating Ventilation and Air Conditioning) is adapted to increase the comfort of the cabin environment for train. The train HVAC duct system has very long duct and many outlets due to the shape of a train set. the duct cross section shape is limited by a roof structure and equipments. Therefore, the pressure distribution and flow uniformity is an important performance indicator for the duct system. In this study, the existing blow down type HVAC duct system for a train was supplemented to improve the flow uniformity by applying a design method combining design of experiment (DOE) with numerical analysis. The design variables and the test sets were selected and the performance for each test set was evaluated using CFD(Computational Fluid Dynamics). The influence of each design variable on the system performance was analysed based on the results of the performance evaluation on the test sets. Furthermore, the optimized model, whose the flow uniformity was improved was produced using the direct optimization(gradient-based method). Finally, the performance of the optimized model was evaluated using numerical analysis, and it was confirmed that its flow uniformity has indeed improved.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2017.04a
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• pp.81-81
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• 2017

본 연구는 전산유체역학(CFD)을 이용하여 트랙터 캐빈 내부의 온도 변화 시뮬레이션 모델을 개발하고 이를 통해 공조장치의 위치를 최적화 하는 것을 목적으로 하였다. 자동차나 열차를 대상으로 시뮬레이션을 이용한 차량 내부의 유동 해석 연구 사례는 많으나, 트랙터를 대상으로 한 연구 사례는 적다. 이에 트랙터의 공조장치를 설계하고 그 성능을 검증할 때 시뮬레이션 모델을 활용한다면, 인력, 시간 등의 손실을 줄일 수 있을 것이다. 본 연구에서는 상용 CFD 프로그램을 활용하여 공조 장치의 위치에 따른 세 가지 트랙터 캐빈 모델을 제작한 뒤, 각각의 모델에 대해서 열 유동 해석을 수행하였다. 시뮬레이션 결과가 실제 트랙터의 시험 결과와 비슷한 경향을 보이고 있음을 확인할 수 있었으며 이를 통해 모델의 적합성을 확인하였다. 또한 세 가지의 캐빈 모델 중 탑승자에게 가장 쾌적한 환경을 제공할 수 있는 모델은 기존의 국내 트랙터와 같은 천정부에 공조 장치가 있는 것이 아니라, 핸들이 있는 전면부에 위치하는 것이 가장 적합하다는 것을 확인할 수 있었다

• Journal of Distribution Science
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• v.16 no.7
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• pp.17-24
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• 2018

Purpose - This study focuses on the quality of nonverbal communication by the flight attendants at the airline, and the factors that contribute to improve customer behavior, thereby providing positive implications for corporate management. Research, design, data, and methodology - For the empirical analysis of this study, reliability analysis and frequency analysis were conducted. T-test and ANOVA analyses were performed. In addition, the effects of nonverbal communication have on customer behavior have regressed analysis. The collected data was empirical suing the SPSS Win 18.0. Results - Among the non-verbal communication qualities were found to significantly influence customer attitudes, and demographic differences in airline flight attendants were also shown to influence their perceptions. Empirical analysis revealed significant differences in demographic characteristics between gender, age and airlines used. Conclusions - All of the non-verbal communication's attributes were found to significantly impact customer attitude. It is used to train the importance of nonverbal communication quality for the role of cabin crew members and to enhance the loyalty of the customers to Airline. This study identifies the relationship between the impact of non-verbal communication quality on customer attitudes and implies the importance of non-verbal communication quality for airline flight attendants. Also, this study suggests that there is a close mechanism between the nonverbal communication and the customer attitudes to airlines.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.23 no.4
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• pp.125-132
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• 2015

항공기 추락 시 충돌충격단계에서 사상자가 가장 많이 발생하는 것으로 나타나고 있다. 대부분의 경우, 승객들은 두부손상으로 의식을 잃게 되어 비상탈출에 실패하여 사망에 이르게 된다. 이에 대한 대응책으로 항공기 제작사들은 내구성이 강화된 항공기 좌석을 설계 및 제작하여 설치하고 있다. 객실에서는 승객들이 충격방지자세를 취함으로써 부상을 최소화할 수 있다. 승객들에 대한 충격방지자세 안내는 모든 항공사가 시간적 여유가 있는 비상상황에서만 객실승무원이 안내방송과 함께 시범을 보이도록 절차가 수립되어 있다. 그러나 갑작스런 사고의 경우 승객들은 충격방지자세에 대한 정보를 전달받지 못한 상태에서 사상의 위험에 직면하게 된다. 본 논문은 SHEL 모델을 적용하여 승객과 사상자발생 환경, 승객과 충격방지를 위한 안전절차, 승객과 승객안전정보 전달매체, 승객과 객실승무원등의 상호작용에 내재된 위해요소를 체계적으로 규명하고 객실안전에 대한 법규 및 절차 등의 개정을 제시함으써, 항공기사고로 인한 사상자 발생에 대한 근본적인 대안을 제시하여 항공안전 증진에 기여하고자 한다.

• Journal of the Korea Society of Computer and Information
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• v.13 no.4
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• pp.221-230
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• 2008

We Studied current Flight Information System everyone employing, and this paper designed a next generation Ubiquitous Flight Information System. Studied a Ubiquitous Flight Information System regarding AVOD, game TV, cellular phone, cabin Internet use for a customer, and airline and control of Air Traffic Service, Air Traffic Control, in seat reservation, transportation, ticketing and luggage back-tracking and airplanes in earthly service. We Designed for a Next Generation Ubiquitous Flight Information System and for necessary for network security, system security of information security system, and derived from comparative analysis of improvement point and difference to existing Ubiquitous Flight Information System and Next Generation Ubiquitous Flight Information as was based on result of research. Present vision to aerial the result of research world of this paper related industry, and ensure safety and communication efficiency and a customer and flight satisfaction, efficiency, and will reclaim the new horizon to the Flight Information Industry.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2013.10a
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• pp.291-291
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• 2013

The interior vehicle noise due to the exterior aerodynamic field is an important topic in the acoustic design of a car. The air flow detached from the A-pillar and impacting the side windows are of particular interest as they are located close to the driver / passenger and provides a lower insulation index than the trimmed car body parts. HMC is interested in the numerical prediction of this aerodynamic noise generated by the car windows with the final objective of improving the products design and reducing this noise. The methodology proposed in this paper relies on two steps: the first step involves the computation of the exterior flow and turbulence induced non-linear acoustic field using the CAA(Computational aeroacoustics) solver CAA++. The second step consists in the computation of the vibro-acoustic transmission through the side window using the finite element vibro-acoustic solver Actran. The internal air cavity including trim component are included in the simulation. In order to validate the numerical process, an experimental set-up has been created based on a generic car shape. The car body includes the windshield and two side windows. The body is made of aluminum and trimmed with porous layers. First, this paper describes the method including the CAA and the vibro-acoustic models, from the boundary conditions to the different components involved, like the windows, the trims and the car cavity is detailed. In a second step, the experimental set-up is described. In the last part, the vibration of the windshield and windows, the total wind noise level results and the relative contributions of the different windows are then presented and compared to measurements. The influence of the flow yaw angle (different wind orientation) is also assessed.

• The Korean Journal of Air & Space Law and Policy
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• v.33 no.2
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• pp.199-224
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• 2018

Aviation's safety record continues to improve yearly, especially with respect to passenger and crew injuries and deaths. However, although the number of accidents has decreased over the decades, there are still many events, such as landings short of the runway and runway excursions, both of which pose threats to passenger and crew safety. Surviving any kind of aviation accident depends on the physiological threat and stress of the impact(s), the extent to which the physical structure surrounding the passengers and crew remains intact, and the ability of the passengers and crew to be able to escape the wreckage. The one action that both passengers and crew can carry out to help decrease the likelihood of crash-related injury or death is to assume an emergency brace position. Doing so has been demonstrated over several decades to improve survivability. While cabin crew are taught (and then might have to teach passengers in an emergency about the emergency brace position), passengers in many parts of the world never learn about the brace position unless they are involved in an emergency in which there is time to prepare for the landing. This lack of provision of information is related to the fact that most airlines do not provide information in the preflight safety briefing and some do not even provide the information in the passenger safety cards. Many countries do not require their airlines to do so, a fact, which in turn, is related to the lack of mention of the brace position in ICAO's Annex 6. Until standards and recommended practices are changed at the highest world level, passengers will continue to be deprived of this vital, life-saving information that they can use, potentially to help save their own lives.

• The Journal of the Acoustical Society of Korea
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• v.29 no.8
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• pp.497-503
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• 2010

In this paper, evaluation of noise reduction performance of HVAC system for ships by means of HVAC mock-up system is presented. Test is done for six different types of HVAC elements including room unit, silencer, etc. It is found that when diameter of silencer is small and air flow is large, flow noise degrades insertion loss. However, as diameter of silencer becomes larger, the effect of flow noise becomes smaller, and insertion loss up to 25 dB is measured. It is observed that insertion loss of diffuser type room unit is usually between zero and 10 dB, whereas that of the nozzle type room unit can be down to - 15 dB. In addition, it is shown that changing duct arrangement can reduce cabin noise by up to 2 dB, and providing same air flow to each room unit is crucial for generating less noise.