Comfort Evaluation Method Research Articles

<b>Evaluation Method of Passenger Thermal Comfort Considering Effects of Airflow by Cross-flow Fan in Commuter Vehicles in Summer</b>

<b>Evaluation Method of Passenger Thermal Comfort Considering Effects of Airflow by Cross-flow Fan in Commuter Vehicles in Summer</b>

A novel wind comfort evaluation method for different airflows by considering dynamic characteristics of wind direction and velocity

The dynamic velocity characteristics of wind have been studied over the past several decades. However, there was a lack of consideration for the incoming flow directions. Besides, the comfort assessment studies mainly focused on thermal comfort from the mechanism of heat transfer instead of wind comfort from the mechanism of tactile stimuli. This study carried out a mixed indoor and outdoor experiment. The indoor experiment was conducted with a room temperature of 29 °C and a relative humidity of 50%, which closely resembled the outdoor environmental conditions. Totally 17 healthy subjects dressed at 0.36 clo and being sedentary were exposed to five kinds of airflow during the experiment. According to the results, outdoor true natural wind was more preferred than directly supplied wind. This paper also proposed a novel wind comfort (WC) model by considering various air parameters. The model relied on tactile stimuli, which were the reflections of wind pressure fluctuations and could be affected by changes in velocity and direction of airflows. Based on these two dynamic characteristics, four wind perceptions, including wind intensity vote (WIV), velocity variation sense (VVS), direction variation sense (DVS) and overall enveloping sense (OES) were introduced and linearly regressed. The findings revealed that not only velocity but also the direction could affect the wind comfort evaluation. This paper will hopefully provide a better understanding of impacts of incoming flow directions on comfort and further rethink a novel route of dynamic wind environment imitation for future indoor environments.

Influence of landscape interventions on thermal comfort under time-varying building shadow; new Gwanghwamun square case, Seoul, South Korea

This study investigated the cooling effects of landscape interventions and their relative magnitude under hybrid urban context including time-varying building shadow cast. The study focused on the practical design alternatives, rather than experimental scenarios. We conducted outdoor thermal comfort (OTC) simulation using ENVI-met, and spatial-temporal comparison analysis for three green space expansion interventions for new Gwanghwamun square, Seoul, South Korea. In addition, we statistically analyzed the relationship between TCR (tree coverage ratio), GCR (green coverage ratio), WCR (water coverage ratio) and PET (Physiological Equivalent Temperature). The correlation and regression coefficients of the relationships under different building density, building locations and shadow cast conditions were compared. As a result of three interventions comparison, the comfort zone increased almost two times, while the discomfort zone decreased to ≈70% of the current condition in the long-term alternative. As TCR increases 22%, PET decreases up to 2.6 °C in average. Tree coverage ratio showed significant importance among the landscape elements. The influence of trees was slightly different for different contexts; larger cooling effect was found in no building shadow cast and low-density buildings. However, the difference was not noticeable; the influence of trees is still effective under building shadow cast and high-density buildings. Moreover, for high tree density area (TCR>50%), temporal gap of thermal comfort between measured time that mainly caused by building shadow change was greatly reduced compared to low tree density area (TCR<5%), which suggest the important role of tree in providing consistent thermal comfort. This study provides scientific evidence for trees’ cooling effect and its relative magnitude under diverse built contexts of N–S oriented urban canyon. This study also contributes to developing an inclusive thermal comfort evaluation method based on both temporal and spatial scales for the effective comparison of real-world design alternatives.

Oxygen comfort evaluation method based on symptom index for short-term internal migrants to Tibet

In Tibet, the hypobaric-hypoxic environment found at high altitudes leads to dysfunction in short-term internal migrants and has noticeable effects on physiology, psychological health, and comfort level. Therefore, it is essential to accurately determine the degree of hypoxia and improve the hypoxic environment of plateaus. Despite advances in the medical diagnosis and treatment of pathological hypoxic injuries, there are some limitations in the oxygenic evaluation of internal migrants with mild hypoxia. An oxygen comfort evaluation method (OCEM) based on typical anoxic symptomatology and physiological indices is proposed in this study. Experiments with different oxygen concentrations were conducted to measure anoxic symptomatology and physiological indices. Using item and exploratory factor analyses, 19 symptom indices were screened to predict oxygen sensation in humans. Finally, the OCEM was established using an artificial neural network and fuzzy mathematics method and its accuracy was verified through a field survey. The results showed that the artificial neural network model using symptomatologic indices could predict human oxygen sensation, with an area under the receiver operating characteristic curve of 0.630–0.913 and prediction accuracy of 93 %. Oxygen comfort can be predicted from the oxygen sensation and typical physiological indices using the fuzzy mathematics method; the weighted kappa coefficient was 0.825, indicating a strong correlation between the predicted and actual values. The proposed OCEM can help determine the oxygen comfort conditions of high-altitude internal migrants and provide a basis for indoor oxygen environment regulation in high-altitude buildings.

Evaluation of Pedestrian Comfort for a Footbridge with Hinged Piers

To study the standardized evaluation method of vibration comfort of pedestrian bridges, the effect of the transient response term is ignored based on the generalized single degree of freedom (SDOF) method with reference to the American Institution of Steel Construction inc (AISC 11) specification. The resonance conditions between the crowd and the bridge structure are also considered, and the pedestrian bridge structure is simplified to an SDOF system. Then, the peak acceleration of the structure under crowd excitation is directly calculated using the generalized crowd load, and the comfort evaluation is carried out according to the German EN03 code and the Chinese code. For a new pedestrian bridge with hinged piers, human-induced vibration tests were carried out to obtain the structural acceleration time response data under various crowd load excitation conditions, and the acceleration values calculated with the numerical simulation method, the frequency response function method, the generalized SDOF method, and the proposed method were compared with field measurements. The results show that for the normal excitation condition with a crowd density less than or equal to 0.2 person/m2, the acceleration maximum error for the proposed method is between 4.22% and 13.28%. The error is only 6.35% compared with the finite element simulation results. The method can derive peak acceleration by performing only modal tests, eliminating errors caused by different testers and errors due to deflection measurements. It saves considerable time cost and economic cost, and improves the speed of pedestrian bridge comfort evaluation. Therefore, the method proposed for the first time in this study can accurately assess the human-caused vibration comfort of pedestrian bridges with articulated piers. Although the hinged-pier and column steel pedestrian bridge meets the code requirement of a vertical first-order frequency greater than 3 Hz, it is recommended to add TMD vibration damping measures to the bridge in order to improve pedestrian comfort.

Railways Passengers Comfort Evaluation through Motion Parameters: A Systematic Review

Railways are one of the most widely used mass transportation systems. Its superior transportation capacity, low environmental impact, high safety, and comfort have been leading to a continuous increase in passengers. To keep this trend going, it is crucial to improve the railways’ attractiveness and comfort levels. A rail journey’s comfort performance is rather complex, involving the analysis of multiple factors. Those raised by the vehicle motion and seat performance are the focus of vehicle designers’ concerns. Therefore, only a combination of static and dynamic comfort methodologies can accurately characterize passengers’ comfort. This work aimed to perform a systematic review concerning the comfort evaluation of train passengers. The bibliographic search yielded 62 studies on static and dynamic comfort evaluation methods. Results show a lack of experiments conducted on real rail environments, leading to weak conclusions regarding the real in-service conditions that train users face. Moreover, an investigation gap concerning the simultaneous application of both static and dynamic methodologies was observed. Therefore, more investigations are needed to evaluate and increase passengers’ comfort and promote rail usage as a daily transportation system.

Evolutionary computation-based multitask learning network for railway passenger comfort evaluation from EEG signals

As a core indicator of the railway service industry, the comfort of the railway passengers is an important aspect to measure the advancement of railway technology. The accurate evaluation of railway passenger comfort has received much attention from academia and industry. The EEG-based comfort evaluation method has been hailed as the gold standard due to its rich quantity of information and objectivity. In this study, an evolutionary computation-based multitask learning network named EEG-DEMTL is proposed to evaluate railway passenger comfort from EEG signals. In this network, the multitask learning structure fully exploits the relationship between subtasks such as passenger emotion and the main task, which is passenger overall comfort. Furthermore, the weight definition method based on the differential evolution (DE) algorithm is used to select the best weight setting. To verify the validity of our proposed method, field experiments in a high-speed railway (HSR) are designed, and comfort perceptions and EEG signals of 20 passengers are collected. Compared with the baseline models, which include the support vector machine, K-nearest neighbour and decision trees, the proposed EEG-DEMTL model achieves the best performance. In addition, the comparison results between several weight settings of MTL show that the DE weights can improve the evaluation performance by 6.30%. This research proposes a novel EEG-based method to meet the requirements of railway passenger comfort evaluation and offers a neurological explanation for railway passenger comfort.

Evaluation and prediction method of railway passenger long-term vibration comfort under complex operating conditions

Vibration contributes large increases in railway passenger discomfort during long-term sitting. Discomfort caused by vibration may differ in different operation conditions. This paper conducted field measurements to investigate the interrelationships between the three. Participants completed a 240-min train journey with their whole-body vibration, subjective comfort ratings and train operating parameters being recorded. A large correlation was observed between the estimated vibration dose value and subjective comfort. The relationship that vibration magnitude significantly increases with increasing the train speed and tunnel density was also found and quantified. A vibration exposure limit of 2.08 m/s1.75 corresponding to the boundary between subjective ratings of comfortable and discomfortable was obtained. Based on the exposure limit and the quantified relationship, a vibration comfort prediction method that can calculate the passenger’s maximum tolerance time under a given operation condition was proposed and may help in determining the optimal operating speed and tunnels distribution to alleviate vibration discomfort. Practitioner summary: Similar to the guide to effect of vibration on health in current standard, a vibration exposure limit regarding comfort was provided for reference when assessing long-term vibration comfort. Meanwhile, a prediction method was proposed for determining the best train operating speed and tunnels distribution, thereby alleviating railway passengers’ vibration discomfort.

A thermal comfort evaluation on vehicular environments based on local human body thermal sensations

With the rapid development of the automobile industry and increasing demand for automobiles, consumers also have more and more car requirements. They do not only consider energy, safety and price but also expect a good indoor environment and improved thermal comfort. In order to construct and apply a thermal comfort evaluation method suitable for Chinese consumers, a relationship between the equivalent space temperature and the thermal sensation was obtained by collecting characteristic thermal sensation data of the human body in different environments. An evaluation method based on whole-body and local thermal comfort sensation characteristics for adult Chinese males and females was designed, At the same time, the study found that women's tolerance for thermal sensation is lower and the thermal comfort zone is relatively smaller. In order to explore the accuracy of the evaluation method and a typical non-uniform vehicular environment was selected to verify the findings. The local and whole-body equivalent space temperature of the co-driver seat in the vehicle was tested with a warm dummy, through which whole-body and local thermal sensation values were predicted. The local and whole-body thermal sensation was tested with subjects' subjective experience under the same conditions. The predicted thermal sensation obtained through the equivalent space temperature was compared to the subjective experience results, and the correlation reached up to 0.911, while significance (two-tailed) only reached 0.002, it was possible to predict the thermal sensation vote within an accuracy level of 0.3 point, further proving the accuracy of the whole-body and local thermal comfort evaluation method for adult Chinese male thermal sensation characteristics as proposed in this paper. The results obtained in this study can be used to predict environmental thermal comfort.

A Comprehensive Method to Evaluate Ride Comfort of Autonomous Vehicles under Typical Braking Scenarios: Testing, Simulation and Analysis

To highlight the advantages of autonomous vehicles (AVs) in modern traffic, it is necessary to investigate the sensing requirement parameters of the road environment during the vehicle braking process. Based on the texture information obtained using a field measurement, the braking model of an AV was built in Simulink and the ride comfort under typical braking scenarios was analyzed using CarSim/Simulink co-simulation. The results showed that the proposed brake system for the AV displayed a better performance than the traditional ABS when considering pavement adhesion characteristics. The braking pressure should be controlled to within the range of 4 MPa~6 MPa on a dry road, while in wet road conditions, the pressure should be within 3 MPa~4 MPa. When steering braking in dry road conditions, the duration of the “curve balance state” increased by about 57.14% compared with wet road conditions and the recommended curve radius was about 100 m. The slope gradient had a significant effect on the initial braking speed and comfort level. Overall, the ride comfort evaluation method was proposed to provide theoretical guidance for AV braking strategies, which can help to complement existing practices for road condition assessment.

Development of a gripping comfort evaluation method based on numerical simulations using individual hand finite element models

Development of a gripping comfort evaluation method based on numerical simulations using individual hand finite element models

Development of a gripping comfort evaluation method based on numerical simulations using individual hand finite element models

Development of a gripping comfort evaluation method based on numerical simulations using individual hand finite element models

Optimization Study on the Comfort of Human-Seat Coupling System in the Cab of Construction Machinery

The seat of a construction machinery cab is used as the research object. For the current human-seat coupling system comfort research methods and optimization index deficiencies, the seat body pressure comfort and vibration comfort at the same time optimized. Based on the more specialized Toyota 50 percentile dummy model, a human-seat finite element simulation model is established, and the body pressure distribution and vibration response are simulated and calculated. The transverse and longitudinal pressure distributions of the backrest and seat cushion and the pressure map are used to verify the simulation model’s body pressure comfort evaluation indexes. At the same time, the vibration response test is used to verify the vibration comfort evaluation indexes of the simulation model. The test results show that the accuracy of each evaluation index of the established coupling model is greater than 85%, which can provide model support for the subsequent optimization work. In order to improve the comfort of the seat of construction machinery during operation, the hardness of the upper sponge and lower layer sponge is reduced and increased by 10% and 15%, respectively, on the original seat. The body pressure comfort evaluation indexes of the ischium peak pressure, ischium mean pressure, thigh peak pressure and thigh mean pressure are used to evaluate the improved seat. The proposed optimization scheme is to reduce the hardness of the upper sponge and lower layer sponge of the seat cushion by 10% to improve the seat body pressure comfort. Finally, the evaluation indexes of body pressure comfort and vibration comfort are verified by four subjects in an improved seat, and the cushion pressure of different subjects is reduced while the vibration isolation rate is increased, which shows the rationality of the proposed optimization scheme. In addition, the evaluation results of the improved seat are different for subjects of different body sizes, with the most significant improvement for the subject of greater height and weight. The modeling and comfort evaluation methods adopted in the paper can provide a reference for the design and development of the seat.

Quantitative evaluation method of human comfort under the influence of blast vibration based on human physiological indexes and its application

To reasonably assess the impact of blasting disturbance on personnel in the adjacent area and to protect the safety and physical and mental health of personnel, it is the key to construct a human comfort evaluation system under the impact of blasting vibration. In view of the uncertainty of human subjective feelings in the existing evaluation system of human comfort under the influence of blasting vibration, the human vibration response experiment is carried out by simulating blasting vibration through a shaking table, and the quantitative relationship between blasting vibration parameters, ECG indicators, and human subjective feelings is analyzed by combining with human ECG indicators to construct the evaluation system of human comfort under the influence of blasting vibration. At the same time, the evaluation system is applied to the actual project with Wuhan Metro Line 5 as the engineering background by combining numerical calculation methods. The results show that: the vertical direction is the main vibration direction affecting human comfort, and the impact of vibration on the human body is related to the main vibration sensation parts of the human body, and the degree of impact gradually increases when the main vibration sensation parts moves up from the feet to the head; There is a quantitative relationship between the decreased ratio of human ECG index RMSSD and blasting vibration parameters as well as human subjective feelings, when the decrease ratio of human RMSSD is >0.28, the extent to which the human feels the degree of annoyance cannot be ignored, and the vibration velocity and frequency (0.7 cm/s, 80 Hz) in the vertical direction of the ground surface at this time can be used as the control threshold of blasting works in the adjacent densely populated areas. It is recommended that the maximum explosive charge in the single delay of the subway tunnel blasting excavation does not exceed 0.32 kg.

Study on indoor adaptive thermal comfort evaluation method for buildings integrated with semi-transparent photovoltaic window

Semi-Transparent Photovoltaic (STPV) windows have the potential of active energy-saving and have attracted more attention in recent years. Due to the selective absorption effect of solar cells on solar radiation, the indoor thermal environment and human thermal comfort of buildings integrated with STPV windows are considerably different from that with clear glass windows, and there are few studies on this. In this paper, the indoor human thermal comfort of buildings integrated with STPV window was investigated. Firstly, experiments and subjective questionnaires for the indoor environment were conducted in STPV and clear glass window buildings respectively. Secondly, the influence of illuminance on thermal sensation was statistically analyzed, with the consideration of visual effect, non-visual effect, as well as visual and non-visual coupling effect respectively. On this basis, an innovative thermal comfort evaluation method was provided. The thermo-physiological effect, light-physiological effect and light-psychological effect were comprehensively considered in this method. Finally, the reliability was verified by comparing with TSV. According to tests and questionnaires, it was found that the indoor thermal environment of the STPV window was an uneven thermal environment, and the subjective thermal sensation was more inclined to be slightly warm. When investigating the effect of illuminance on thermal sensation considering visual and non-visual coupling effect, it was found that illuminance had a significant influence on thermal sensation in different illuminance ranges. Meanwhile, it indicated the coupled effect of thermal environment and daylight environment on the thermal comfort of human.

Decision-Refillable-Based Two-Material-View Fuzzy Classification for Personal Thermal Comfort

The personal thermal comfort model is used to design and control the thermal environment and predict the thermal comfort responses of individuals rather than reflect the average response of the population. Previous individual thermal comfort models were mainly focused on a single material environment. However, the channels for individual thermal comfort were various in real life. Therefore, a new personal thermal comfort evaluation method is constructed by means of a reliable decision-based fuzzy classification model from two views. In this study, a two-view thermal comfort fuzzy classification model was constructed using the interpretable zero-order Takagi–Sugeno–Kang (TSK) fuzzy classifier as the basic training subblock, and it is the first time an optimized machine learning algorithm to study the interpretable thermal comfort model is used. The relevant information (including basic information, sampling conditions, physiological parameters, physical environment, environmental perception, and self-assessment parameters) was obtained from 157 subjects in experimental chambers with two different materials. This proposed method has the following features: (1) The training samples in the input layer contain the feature data under experimental conditions with two different materials. The training models constructed from the training samples under these two conditions complement and restrict each other and improve the accuracy of the whole model training. (2) In the rule layer of the training unit, interpretable fuzzy rules are designed to solve the existing layers with the design of short rules. The output of the intermediate layer of the fuzzy classifier and the fuzzy rules are difficult to explain, which is problematic. (3) Better decision-making knowledge information is obtained in both the rule layer of the single-view training model and in the two-view fusion model. In addition, the feature mapping space is generated according to the degree of contribution of the decision-making information from the two single training views, which not only preserves the feature information of the source training samples to a large extent but also improves the training accuracy of the model and enhances the generalization performance of the training model. Experimental results indicated that TMV-TSK-FC has better classification performance and generalization performance than several related state-of-the-art non-fuzzy classifiers applied in this study. Significantly, compared with the single view fuzzy classifier, the training accuracies and testing accuracies of TMV-TSK-FC are improved by 3–11% and 2–9%, respectively. In addition, the experimental results also showed good semantic interpretability of TMV-TSK-FC.

Structural vibration performance test based on smart phone and improved comfort evaluation method

In view of the lack of portability and real-time performance of traditional instruments, the monitoring module based on smartphones which can achieve the acquisition of structural acceleration is developed. The accuracy and performance of smart phone through dynamic test is verified. Aiming at the shortcomings of the comfort evaluation method in the scope of application and evaluation parameters, the idea of displacement and velocity limits is put forward, and the evaluation limits applicable to different structures are given. The results show that the limits of displacement and velocity can be used as supplementary indexes for comfort evaluation of flexible structures.

Global Vibration Comfort Evaluation of Footbridges Based on Computer Vision.

The vibration comfort evaluation is a control standard other than strength and deflection, but the general comfort evaluation method only considers the response of the mid-span position and does not consider the difference in the vibration response of different positions at the same time. It is crucial to study how pedestrians actually feel when they walk on footbridges. The computer vision-based vibration comfort evaluation method is a novel method with advantages, such as noncontact and long-distance. In this study, a computer vision-based method was used to evaluate the global vibration comfort of footbridges under human-induced excitation. The improved Lucas–Kanade optical flow method is used for multitarget displacement identification of footbridges. Additionally, the YOLOv5 algorithm for pedestrian detection is used to obtain the position information of pedestrians on the footbridges. Then, according to the pedestrian position information, the structural responses of different pedestrian positions corresponding to time periods are extracted from the displacement responses of each point, and they are combined to obtain the structural global displacement. The global acceleration can be obtained by calculating the global displacement. The rms value can be calculated based on the global acceleration and compared with the standard for comfort evaluation. The global comfort evaluation method is validated by pedestrian walking experiments with different frequencies on a laboratory footbridge. The experimental results show that the computer vision-based global comfort evaluation method for footbridges is feasible and is a more specific and real-time comfort evaluation method.

A comfort evaluation method based on an intelligent car cockpit

AbstractWith the rapid development of automobiles, car cockpits are becoming more and more intelligent and advanced, and the intelligent requirements of automobile cockpits are gradually increasing. However, the real value of intelligence can only be realized when it makes passengers in a cockpit feel comfortable. In this study, seven factors that affect passenger comfort in intelligent cockpits are defined. Under these factors, a total of 33 evaluation indicators were developed. The core of the method was to determine the dissatisfaction indicators and degree of dissatisfaction in the intelligent cockpit by analyzing the relationship between people's perceived performance and their expectations. This method was used to evaluate the Tesla Model 3, and it was found in the results that the higher the degree of dissatisfaction with the indicator, the more subjective feedback it had, which in turn proved the effectiveness of the model. According to the degree of dissatisfaction, the indicators affecting comfort were also divided into three levels. This hierarchical division helps clarify which indicators should be prioritized for improvement. Generally, this method has a certain feasibility, which is helpful for the development and redesign of an intelligent car cockpit, and provides some reference strategies for other transportation fields.

Human-Induced-Vibration Response Analysis and Comfort Evaluation Method of Large-Span Steel Vierendeel Sandwich Plate

A steel Vierendeel sandwich plate used as a large-span lightweight floor structure for vibration comfort during crowd gatherings was considered. Taking the steel Vierendeel sandwich plate in Guizhou Museum as an example, through finite element transient analysis, the effects of the structural damping, pedestrian self-weight, floor span, surface concrete slab thickness, and structural parameters on the floor’s acceleration response distribution were deeply studied. According to the distribution characteristics of the acceleration response, a distribution model function was constructed, and a distribution Gauss model of the relationship between the peak acceleration response and the position of the steel Vierendeel sandwich plate was established. A field test of the sandwich plate under human-induced fixed-point excitation was carried out, and the model fitting results were compared with the actual test results. The results showed that the Gaussian model could effectively estimate the peak acceleration response at different positions on the floor. In addition, according to the distribution model, a comfort evaluation method based on the comfort assurance rate was proposed that could greatly reduce the representative value of the acceleration evaluation. The research results provide a reference for the comfort evaluation and corresponding vibration-reduction design of long-span steel Vierendeel sandwich plates.