• Transactions of the Korean Society of Automotive Engineers
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• v.17 no.2
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• pp.126-131
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• 2009

A $CO_2$ heat pump system was designed for both cooling and heating in the cabin of electric vehicles, hybrid vehicles or fuel cell vehicles, In this study, the performance characteristics of the heat pump system without any supplementary heating device were analyzed and the heating performance was compared with the cooling performance for various operating conditions. Experiments were carried out by changing the speed of electric drive compressor, the air flow rate of interior heat exchanger and the air inlet temperature and speed of exterior heat exchanger. Therefore, the cooling/heating capacities and the corresponding COPs are quantified. Also, the heat pump system showed an improved performance for the cooling operation and the heating operation. In this study, the experimental results can be used to evaluate the effect of system design changes on system performance as well as the development of a highly efficient heat pump system.

• Journal of Distribution Science
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• v.15 no.8
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• pp.37-46
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• 2017

Purpose - Many studies have shown the effects of the external images of female flight attendants on the customers' satisfaction. Recently, the perception of male flight attendants has become more important and positive, and airlines are hiring a significant number of male flight attendants every year. Due to the lack of research on the male flight attendant, however, the images of male flight attendants were investigated for this study. Research, design, data and methodology - Using survey techniques with 204 respondents, this study used analytical data based their resulting analysis. Results - The study examined whether the image of the male flight attendant affects the cognitive and emotional perceptions of customers. The focus of the present study is the external image of the male flight attendant, and the following image-component divisions were formed: hairstyle, body type, uniform, speech, and facial expression. Conclusions - The study purpose sought to determine whether the image of the male flight attendant exert effects on the emotional and cognitive images of airlines, and if these images have a positive effect on the customers' satisfaction and loyalty for an airline, so that airlines can use the external image of the male flight attendant to help with its own image reinforcement.

• Journal of Advanced Marine Engineering and Technology
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• v.32 no.8
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• pp.1170-1177
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• 2008

The purpose of this study is to measure and analyze the indoor thermal conditions in the spring of a korean coastal passenger ship which is 590-passenger Ro-Pax type built at 1997. Especially this study has focussed on the relations between the diffuser open ratio, which can be controlled by 12 steps, and the comfort. Followings are the results of this study. (1) The supply air volume to cabins are maximum 4.3 and 2 times more than design quantity when the diffusers in cabins are open 100% and 50%, respectively. (2) Regardless of diffuser open ratio, the supply air maintains constantly high temperature and below 10% of relative humidity through the experimental days. (3) All the cabins are not satisfied with the ASHRAE comfort criterion at the condition of 100% and 50% of diffuser open ratio, because of high temperature and low relative humidity. (4) At a low diffuser open ratio, number of cabins which satisfy the ASHRAE comfort criterion are increased. (5) Humidifying and dehumidifying, and hvac control system of each cabin must be reviewed and studied at the view of passengers to service more comfort environments.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.11a
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• pp.464-473
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• 2006

This paper summarises theoretical and experimental work on the feedback control of sound radiation from honeycomb panels using piezoceramic actuators. It is motivated by the problem of sound transmission in aircraft, specifically the active control of trim panels. Trim panels are generally honeycomb structures designed to meet the design requirement of low weight and high stiffness. They are resiliently-mounted to the fuselage for the passive reduction of noise transmission. Local coupling of the closely-spaced sensor and actuator was observed experimentally and modelled using a single degree of freedom system. The effect of the local coupling was to roll-off the response between the actuator and sensor at high frequencies, so that a feedback control system can have high gain margins. Unfortunately, only relatively poor global performance is then achieved because of localisation of reduction around the actuator. This localisation prompts the investigation of a multichannel active control system. Globalised reduction was predicted using a model of 12 channel direct velocity feedback control. The multichannel system, however, does not appear to yield a significant improvement in the performance because of decreased gain margin.

• Journal of Advanced Marine Engineering and Technology
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• v.32 no.2
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• pp.276-283
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• 2008

The purpose of this study is to measure and analyze the ship's indoor thermal conditions and also to integrate experimental database of those which are supplied and controlled by marine HVAC. On this study, temperature, humidity and air volume of 6 different needs' cabin are measured like previous report on a newly-launched training ship during 25th through 27th of July, 2007. Followings are the results of this study. (1)The air supply volumes to each cabins are measured 250CMH(Recreation room), 800CMH(Conference room), 1.000CMH(Bridge), 5,100CMH(Lecture room) respectively. (2)The temperatures are maintained at $21{\sim}27^{\circ}C$ in almost cabins through measuring period, but the temperatures are fluctuated over ${\pm}4^{\circ}C$ at the bridge and conference room. (3)The relative humidities are shown between $40{\sim}60%$ known as comfort conditions, but the conference room is needed to dehumidified because of over 70% humidity. (4)From the student cabins' measurements which have different supply diffuser(s), it is clear that the design is suitable for this case. (5)Because of temperature diversities, only 32% among the measured data are satisfied with the comfort standard range proposed by ASHREA.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.16 no.12 s.117
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• pp.1252-1261
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• 2006

This paper summarizes theoretical work on the multichannel decentralized feedback control of sound radiation from aircraft trim panels using piezoceramic actuators. The aircraft trim panels are generally honeycomb structures designed to meet the design requirement of low weight and high stiffness. They are resiliently-mounted to the fuselage for the passive reduction of noise transmission. It is motivated by the localization of reduction in vibration of single channel active trim panels. 12-channel decentralized feedback control systems are investigated in terms of the reduction of noise and vibration for three configurations of sensor actuator pairs. Local coupling of the closely-spaced sensor and actuator pairs was modeled using single degree of freedom systems. The multichannel control system is characterized using the state-space model. For the stability point of view, the relative stability or robustness is evaluated by comparing the real part of eigenvalues of the system matrix for the three configurations. The control performance is also evaluated and compared for the three configurations. It is found that the multichannel system can lead to the globalization of the reduction in vibration and radiated noise. It does not appear to yield a significant improvement in the vibration because of decreased gain margin. However, the reduction in the radiated noise is remarkably improved due to the variation of the vibration pattern with the actuation configurations.

• IE interfaces
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• v.11 no.3
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• pp.143-153
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• 1998

Warning control is one of the most important components in driver's cabin for achieving safe driving. The purpose of this study is to suggest ergonomically optimal location and type of passenger car's warning control. An experiment was conducted using driving simulator, in which nine locations and two types of warning controls -push button, rocker switch- were employed as experimental variables, and response time for warning signal and preference for locations and types of warning controls were measured as dependent variables. The results showed that response time for warning signal was the shortest when warning control was located at the middle left corner of the center fascia, and was the second at the middle center of the center fascia. Preference for warning signal was the highest at the middle left comer of the center fascia, and was the second between the steering wheel column and the center fascia. Although push button was not preferred to rocker switch, response time was shorter for push button than for rocker switch. It was suggested from these results that warning control with the type of push button should he located at among the middle left corner of the center fascia, the middle center of the center fascia, and between the steering wheel column and the center fascia.

• Journal of Distribution Science
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• v.17 no.2
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• pp.43-51
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• 2019

Purpose - This study was intended to provide implications for the importance of color to airlines where the image customers feel about the business is paramount. The importance of colors shown by the airline crew, an important human resource for airlines as contact workers, was investigated. We wanted to present suggestions by investigating and comparing the difference in customer attitude regarding the color of uniforms of the airline crew. Research design, data, and methodology - A survey was conducted to examine differences in perception of airline uniform color, with the research that suggests that the customer's attitude to uniform color will vary. The difference in the perception of passengers according to the colors of the airline uniforms was determined by conducting an empirical analysis. Results - Customers have a different attitude about the color of the uniform of airline's flight attendants' uniform. Full service airlines (FSC) generally have a bright, calm, neat, and heavy-handed feeling, while low-cost carriers (LCC) have a distinctive, dynamic, energetic, and cheerful feeling. Conclusions - An empirical analysis of the study found that customers' attitudes vary by uniform color for each airline. It has also been revealed that Airline's uniform color can communicate the company's goals it wants to convey.

• Journal of the Korean Society of Hazard Mitigation
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• v.10 no.5
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• pp.1-7
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• 2010

Since subway fire disaster at Daegu, Korea smoke control system and passengers evacuation distance has been focused to reform. Existing smoke control facilities need to expand volume of ventilation capacity however, the complicate subway station structure can hardly react dispersion of smokes from massive subway cabin fire. Smoke flow at platform level move upward thought vertical stairway and passengers evacuation goes with same direction. The victims of evacuees from subway station fire mainly due to exposure of heat radiation and smoke. The study demonstration the effect of downward evacuates stairway system by separating evacuation route to smoke movement pass way including saving times of evacuation.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.12 no.6
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• pp.431-436
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• 2002

The interior sound pressure level of the Korean high-speed train(KHST) is predicted by geometrical acoustic method. For the Purpose of assuring the prediction of Interior noise of KHST by the geometrical acoustic scheme, calculated sound level values of the Korean train express(KTX) by Identical geometrical method are compared with measured values of KTX prototype vehicle by experiment. Contribution of individual sound source of KHST vehicle Into the interior response positions is calculated and sound sources are classified in influential order. Hence, it is reasonable approach to reduce sound power of most contributing noise source first. Sensitivity of the interior response position's sound pressure level (SPL) with respect to train wall sections' transmission loss are carried on and acoustically sensitive spot is identified, for example window area for passenger cabin case. Those contribution and sensitivity analysis results are suggested to design quieter train efficiently.