• Journal of Mechanical Science and Technology
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• v.15 no.5
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• pp.535-543
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• 2001

This paper presents the ride comfort analysis of a vehicle based on wavelet transform. Traditionally, the objective evaluation of impact harshness is based on the vibration dose value (VDV) and frequency weighting method. These methods do not consider the damping effect of the suspension system of a vehicle. In this paper, the damping is estimated using wavelet transform based on Morlet mother wavelet and its effect is considered for the subjective evaluation of impact harshness of a car.

• Journal of the Korean Society of Clothing and Textiles
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• v.30 no.4 s.152
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• pp.615-622
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• 2006

A tool to evaluate the subjective wearing comfort of caps from the objective measurement of pressure was developed. Comfortable Fittability Index(C.F.I) and Holding Power(HP) were defined to represent the subjective wearing comfort of caps. As a preliminary step to define the Comfortable Fittability Index(C.F.I), average pressure, pressure distribution, standard deviation of pressure were obtained and subjective sensation were evaluated by wearing caps. Also Holding Power(HP) was estimated from wind tunnel testing. Two sets of caps were evaluated, one set made of elastic fabric(F-caps) and the other set made of non-elastic fabric(S-caps). F-caps begin to be taken off by the higher wind velocity and thus exhibited higher values of Holding Power. On the other hand, F-caps exerted lower average pressure, narrower pressure distribution, smaller standard deviation.

• Journal of the Ergonomics Society of Korea
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• v.36 no.3
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• pp.169-181
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• 2017

Objective: The aim of this study was to explore the influence of outdoor weather conditions on subjective responses during physical activity. Background: The largest difference between indoor and outdoor conditions is the existence of the sun. The heat load from the sun has an influence on the heat gain of the human body and the intense degree of solar radiation affected thermal comfort. Method: Thirty eight people were exposed to a range of climatic conditions in the UK. Weather in England does not have extremely hot and cold temperature, and the current study was conducted under warm (summer and autumn) and cool (spring and summer) climates. Measurements of the climate included air temperature, radiant temperature (including solar load), humidity and wind around the subjects. Subjective responses were taken and physiological measurements included internal body temperature, heart rate and sweat loss. Results: This study was conducted under four kinds of environmental conditions and the environmental measurement was performed in September, December, March, and June. The values for sensation, comfort, preference, and pleasantness about four conditions were from 'neutral' to 'warm', from 'not uncomfortable' to 'slightly comfortable', from 'slightly cooler' to 'slightly warmer', and from 'neither pleasant nor unpleasant' and 'slightly unpleasant', respectively. All subjective responses showed differences depending on air temperature and wind speed, and had correlations with air temperature and wind speed (p<0.05). However, subjective responses showed no differences depending on the radiant temperature. The combined effects of environmental parameters were showed on some subjective responses. The combined effects of air temperature and radiant temperature on thermal sensation and pleasantness were significant. The combined effects of metabolic rate with air temperature, wind speed and solar radiation respectively have influences on some subjective responses. In the case of the relationships among subjective responses, thermal sensation had significant correlations with all subjective responses. The largest relationship was shown between preference and thermal sensation but acceptance showed the lowest relationship with the other subjective responses. Conclusion: The ranges of air temperature, radiant temperature, wind speed and solar radiation were $6.7^{\circ}C$ to $24.7^{\circ}C$, $17.9^{\circ}C$ to $56.6^{\circ}C$, $0.84ms^{-1}$ to $2.4ms^{-1}$, and $123Wm^{-2}$ to $876Wm^{-2}$ respectively. Each of air temperature and wind speed had significant relationships with subjective responses. The combined effects of environmental parameters on subjective responses were shown. Each radiant temperature and solar radiation did not show any relationships with subjective responses but the combinations of each radiant temperature and solar radiation with other environmental parameters had influences on subjective responses. The combinations of metabolic rate with air temperature, wind speed and solar radiation respectively have influences on subjective responses although metabolic rate alone hardly made influences on them. There were also significant relationships among subjective responses, and pleasantness generally showed relatively high relationships with comfort, preference, acceptance and satisfaction. Application: Subjective responses might be utilized to predict thermal stress of human and the application products reflecting human subjective responses might apply to the different fields such as fashion technology, wearable devices, and environmental design considering human's response etc.

• Journal of the Ergonomics Society of Korea
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• v.33 no.4
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• pp.255-265
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• 2014

Objective: The purpose of this study was to evaluate comfort levels of functional and non-functional chairs using subjective comfort rating, interface pressure measurement, muscle activity measurement, and skin temperature measurement. Background: Chairs are used for a prolonged period of time for sitting in many places such as the office, at university, at school, in industry, and so on. Almost all people use chairs in their everyday life. The functional properties of the chair are associated with comfort. Method: The subjective evaluation contains questions regarding chair comfort which can be rated with five point scale. The body-seat interface pressure was measured using a pressure mat system. The symmetry of sitting was measured using electromyography. The change in body part (thigh and buttock) temperature before and after sitting on a chair was measured with an infrared camera. Results: Participants rated significantly (p < 0.05) higher comfort scores for the functional chair in relation to the buttock and thigh region. Also, the participants felt a better cushion effect in the functional chair. When using the functional chair, lower interface pressure, better thermal comfort, and better symmetry of erector spinae muscle activity were observed. Conclusion: Overall, interface pressure measurement, muscle activity measurement, thermal imaging and subjective comfort score results showed that the functional chair was more comfortable than the non-functional chair. Application: The adopted methodologies could be used to measure the seating comfort of train seats.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.23 no.7
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• pp.631-639
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• 2013

Virtual seat method(VSM) which is an evaluation method combined objective and subjective process is used in this study in order to determine seat comfort index of idle vibration of passenger vehicle. The VSM is implemented by two steps which are for objective index in the first step and for subjective estimation in the second step. In the study, two seats mounted on passenger vehicle was compared in terms of dynamic seat comfort by six subjects employed for the VSM method as well as SEAT value which is a conventional objective method. It is concluded that the dynamic comfort index by the VSM is more reliable than the SEAT value thanks to adding subjective evaluation on top of the objective result.

• Journal of the Ergonomics Society of Korea
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• v.12 no.1
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• pp.3-15
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• 1993

The pressure distribution between human body and seat surface has been considered as an important factor affecting seating comfort. However, it is rare to find general guidelines of how to analyze these pressure patterms related to the seating comfort. In order to investigate the relationship between the pressure patterns and the subjective feeling of seating comfort, a high-resolution body pressure measurement system was adopted. The measured patterns showed that the clear distinctions between the comfortable seats. It was also possible to estimate the seating comfort based upon the analysis of the pressure patterns. The further research will be focused on finding out the relationship between physical seat design parameters and the seating discomfort.

• Fashion & Textile Research Journal
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• v.16 no.1
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• pp.153-159
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• 2014

This study evaluates the changes of the subjective hand, preference, comfort and mechanical properties of tricot based artificial suede made from sea-island type micro fibers according to raising condition. The subjective hand and the preference of raised suede for jacket were rated by the 20's and 30's women experts according to raising cycles. Comfort properties were evaluated by air permeability, water vapor transmission, and thermal transmission. Mechanical properties were measured by the KES-FB system. The subjective hand of artificial suede was categorized into three hand factors: smoothness, warmness and thickness. Smoothness, warmness and thickness perception increased with raising cycles which affected hand preference and luxuriousness perception. The thickness and wale density of suede increased with the number of raising. Suede became more compact and less pliable and less stretchable due to increased fabric thickness; in addition, the surface of suede became smoother and compressive since the surface evenness of suede improved with smaller fiber fineness and an increased amount of naps covered the base fabric. Furthermore, water vapor transmission decreased and thermal insulation increased. The best raising conditions for artificial suede was four cycles in which artificial suede was preferred without changes in physical properties.

• Journal of the Korean Home Economics Association
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• v.40 no.3
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• pp.11-20
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• 2002

The purposes of this study were to investigate the subjective wearing sensation of sleepwear, and to evaluate the comfort properties of fabrics used in the sleepwear. Design of experimental clothing was pajamas made with four types of woven fabrics: plain weave and satin weave made by cotton and polyester. The comfort properties were evaluated with respect to thermal retention, Qmax, moisture regain, water vapor transmission, and air permeability. The wear trials of experimental clothing were performed in two different environments, single-detached unit($23{\pm}1^{\circ}C$, $45%{\pm}3%$ R.H.) and apartment($27{\pm}1^{\circ}C$, $40{\pm}3%$ R.H), to evaluate microclimate temperature and humidity, and subjective wearing sensation. The results obtained from this study were as follows: 1. There were significant differences between the two environments on the clothing microclimate. 2. In the single detached unit environment, the microclimate temperature who wore cotton sleepwear was significantly higher than that of subjects wore the polyester sleepwear, whereas the microclimate humidity who wore polyester sleepwear was higher than that of subjects wore the polyester sleepwear. 3. In the apartment environment, the microclimate temperature who wore the polyester sleepwear showed higher than that of cotton sleepwear, whereas there was no significant difference between the cotton and polyester sleepwear on the microclimate humidity. 4 There were partially significant differences in subjective wearing sensation according to the fiber md weaving type of sleepwear regardless environment. 5. There were also partially significant correlations among the heat/moisture transmission properties of fabrics, the clothing microclimate and the subjective wearing sensation of sleepwear.

• Transactions of the Korean Society of Automotive Engineers
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• v.24 no.1
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• pp.59-66
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• 2016

The evaluations of ride comfort, handling, and steering feeling have been known as one of the dominant factors for vehicle performance assessment. However, those factors have not been analyzed in-depth in conjunction with general ride and handling design parameters. Thus, we have surveyed some previous studies dealing with subjective parameters and quantitative design parameters. We expect this paper provides some guidance to the future research on the field.

• Journal of the Korean Home Economics Association
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• v.35 no.5
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• pp.213-219
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• 1997

The purpose of this study is to propose a model for evaluating comfort of indoor environment based on residents' subjective respones. The questionnaire survey was given to the residents at apartment complex located in Ilsan, Kyunggi-Do. The following are the results obtained in this thesis. The results of path analysis on comfort revealed that direct effects to comfort were the satisfaction on thermal environment, indoor air environment and sound environment, and the cognition on indoor air environment and sound environment. An evaluation formula of comfort by the factors of direct effects was given. This formula is recommended to evaluate comfort for pp.O.E(post occupancy evaluation)by residents.