• Title/Summary/Keyword: driver stress

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Field Application Evaluation of Black VES-LMC (흑색 VES-LMC의 현장적용성 평가)

  • Jung, Won-Kyong;Kil, Yong-Su;Kim, Yong-Bin;Yun, Kyong-Ku
    • International Journal of Highway Engineering
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    • v.13 no.1
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    • pp.177-183
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    • 2011
  • VES-LMC(very-early strength latex modified concrete) has been widely used as repair material for bridge deck overlay or rehabilitation, because it could be opened to the traffic after 3 hours of curing. However, the bright color of VES-LMC disturb driver's sigh. A black VES-LMC, matching to asphalt concrete, was developed and applied at a filed for driver's comfort and safety. The black VES-LMC included 2% carbon black in cement weight ratio. A series of performance evaluation for black VES-LMC was done in terms of field applicability, pavement color and temperature change. The field applicability test result showed that there were no change of workability, slump and air void, and the compressive strengthen developed more than 20MPa after 4 hours of placement. The thermal stress of black VES-LMC was smaller than that of OPC and asphalt concrete, which means the stability of black VES-LMC. The performance evaluation result showed that the black VES-LMC could prevent road icing at below zero temperatures and promote thawing at melting temperature.

Simulation Analysis on the Impact of Racing Car with Space Frame (스페이스 프레임을 가진 경주용 차량의 충돌에 관한 시뮬레이션 해석)

  • Cho, Jae-Ung;Bang, Seung-Ok;Kim, Key-Sun
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.11 no.7
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    • pp.2341-2348
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    • 2010
  • In this paper, strain and stress on space frame are analyzed at racing car under crash loads. As the deformation is reduced to a minimum during crash and the vulnerable parts are grasped, the safety of driver is ensured. The vehicle frame is modelled with truss structure by inputting the material property of carbon steel on finite element analysis. The increase of impulse momentum is due to speed change at frontal collision. This influence effected on vehicle frame is also analyzed by ANSYS program. The deformation of the frame is studied by applying the crash loads at front, side and rear directions. Though the influence on the seat of driver is small at frontal and rear crash, the deformation due to impact is progressed into this seat. The safety of frame is enhanced by making up for these weak deformations and these results of simulation analysis can be applied to the production of the actual vehicle frame.

A Study on the Vibration Decibel Related to the Shape of Rumble Strip Located on the Highway Tollgate (고속도로 톨게이트 근처 럼블스트립 형태에 따른 진동 데시벨 연구)

  • Kim, Do Wan;Jang, Yeong Sun;Mun, Sung Ho
    • International Journal of Highway Engineering
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    • v.15 no.6
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    • pp.93-101
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    • 2013
  • PURPOSES : The rumble strip installed at the highway near the tollgate has the purpose to reduce the vehicle velocity or prevent sleepiness by awakening people to the danger. These rumble strip has different vibration decibel from the rumble strip shapes, resulting in some fatigue damage to human because a driver suffers from a lot of stress and displeasure. In this connection, the objective of this paper is to analyze the vibration decibel perceived by a driver in the vehicle under some conditions. METHODS : The vibration decibel conveyed from the tire can be analyzed. The frequency analysis methods were used according to DFT (Discrete Fourier Transform) analysis, FFT (Fast Fourier Transform) analysis, CPB (Constant Percentage Bandwidth) analysis. But the frequency analysis method in this paper is the 1/24 OCT(Octave) band analysis because of the convenience of the analysis and the overall vibration amplitude along the frequency. RESULTS : By using the results of the vibration decibel after analyzing the 1/24 OCT band analysis, these results can be compared from some conditions (e.g., rumble strip shape, uniform velocity of a vehicle, road condition, mass of a vehicle). As a result, the numerical values of decibel are not directly proportional to the vehicle velocity. CONCLUSIONS : At the condition that a vehicle is passing by the rumble strip, the value of a vibration decibel at the rumble strip of the cylinder shape is smaller than the rumble strip of rectangular shape regardless of the rumble strip depth and width. At the mass condition, the more a vehicle is massive, the more the vibration decibel increases. At the road condition, the vibration decibel at the wet road is smaller than the value at dry road condition.

A Study on Searching for Reduction of Women EMTs's Stress (여성 구급대원의 현장 스트레스 경감방안 모색에 관한 연구)

  • Kong, Ha-Sung;Lee, Ranny;Lee, Seong-Chul
    • Journal of the Korea Safety Management & Science
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    • v.15 no.4
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    • pp.113-121
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    • 2013
  • The rate that women's EMTs(emergency medical technicians) in fire department occupy is increasing, but my general plan is aimed at suggesting the improving plan for the working environment of women's EMTs paying attention to the duty stresses of increasing women's EMTs, because improvement for the working environment of women's EMTs is being proceeded slowly. I suggested my improving plan for solving the working stress on the basis of a survey of the Recognition against women's EMTs as follows. Firstly, I suggested that physical strength of women's EMTs should be managed well continually via program establishment and a defined evaluation not only by employing a professional person in charge for physical strength in firehouse, but also by replenishing the suitable number for the urgent mobilization. Secondly, I suggested that the suitable number for the urgent mobilization should be increased to 3 including an ambulance driver. Thirdly, I suggested necessity such as the fruitful education and the creation of circumstances that can focus on education for improving participation rate, development of various new educational program, incentive program and penalty. finally, I suggested the fact that is related to the actual re-amendment of the concerned law and ordinance such as not only the smooth treatment of penalty for a traffic signal violation of ambulance and the legal remedy system due to aggravation of a patient's condition during a first-aid course, but also workshop and meeting among the periodical EMTs and administration of special therapy program and sufficient recess.

Analysis of Ventilating Seat Comfort Temperature for Improving the Thermal Comfort inside Vehicles (자동차 실내 열쾌적성 개선을 위한 통풍시트의 쾌적온도 분석)

  • In, Chung-Kyo;Kwak, Seung-Hyun;Kim, Chang-Hoon;Kim, Kyu-Beom;Jo, Hyung-Seok;Seo, Sang-hyeok;Myung, Tae-Sik;Min, Byung-Chan
    • Science of Emotion and Sensibility
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    • v.23 no.4
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    • pp.33-40
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    • 2020
  • As the number of automobile registrations increases and luxury expectations grow, consumers are increasingly interested in indoor environment of vehicles. Therefore, manufacturers have an increasing interest in improving the indoor comfort as well as automobile performance. Research on indoor automobile comfort can help manufacturers increase driver satisfaction and reduce driver stress and discomfort, thereby reducing the risk of traffic accidents. Using electroencephalogram (EEG) measurements, we investigated the change in comfort and comfortable temperature according to the ventilating seat temperature change for both men and women. Results showed that the sensation of comfort was statistically significantly higher at 25℃ than at 28℃. Secondly, there was no statistically significant difference in temperature-based comfort feeling between male and female subjects. In the future, if the correlation between the driver's comfort feeling and the change in ventilating seat temperature is analyzed, it is possible to reduce traffic accidents caused by human error and reduce the electric energy consumption of the automobile.

TGF-β downregulation-induced cancer cell death is finely regulated by the SAPK signaling cascade

  • Han, Zhezhu;Kang, Dongxu;Joo, Yeonsoo;Lee, Jihyun;Oh, Geun-Hyeok;Choi, Soojin;Ko, Suwan;Je, Suyeon;Choi, Hye Jin;Song, Jae J.
    • Experimental and Molecular Medicine
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    • v.50 no.12
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    • pp.4.1-4.19
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    • 2018
  • Transforming growth factor $(TGF)-{\beta}$ signaling is increasingly recognized as a key driver in cancer. In progressive cancer tissues, $TGF-{\beta}$ promotes tumor formation, and its increased expression often correlates with cancer malignancy. In this study, we utilized adenoviruses expressing short hairpin RNAs against $TGF-{\beta}1$ and $TGF-{\beta}2$ to investigate the role of $TGF-{\beta}$ downregulation in cancer cell death. We found that the downregulation of $TGF-{\beta}$ increased the phosphorylation of several SAPKs, such as p38 and JNK. Moreover, reactive oxygen species (ROS) production was also increased by $TGF-{\beta}$ downregulation, which triggered Akt inactivation and NOX4 increase-derived ROS in a cancer cell-type-specific manner. We also revealed the possibility of substantial gene fluctuation in response to $TGF-{\beta}$ downregulation related to SAPKs. The expression levels of Trx and GSTM1, which encode inhibitory proteins that bind to ASK1, were reduced, likely a result of the altered translocation of Smad complex proteins rather than from ROS production. Instead, both ROS and ROS-mediated ER stress were responsible for the decrease in interactions between ASK1 and Trx or GSTM1. Through these pathways, ASK1 was activated and induced cytotoxic tumor cell death via p38/JNK activation and (or) induction of ER stress.

Working Conditions, Job Strain, and Traffic Safety among Three Groups of Public Transport Drivers

  • Useche, Sergio A.;Gomez, Viviola;Cendales, Boris;Alonso, Francisco
    • Safety and Health at Work
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    • v.9 no.4
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    • pp.454-461
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    • 2018
  • Background: Working conditions and psychosocial work factors have acquired an important role explaining the well-being and performance of professional drivers, including those working in the field of public transport. This study aimed to examine the association between job strain and the operational performance of public transport drivers and to compare the expositions with psychosocial risk at work of three different types of transport workers: taxi drivers, city bus drivers, and interurban bus drivers. Method: A sample of 780 professional drivers was drawn from three transport companies in Bogota (Colombia). The participants answered the Job Content Questionnaire and a set of sociodemographic and driving performance questions, including age, professional driving experience, work schedules, and accidents and penalties suffered in the last 2 years. Results: Analyses showed significant associations between measures of socio-labor variables and key performance indicators such road traffic accidents and penalties. Furthermore, multiple linear regression analysis contributed to explain significantly suffered accidents from key variables of the Job Demand-Control model, essentially from job strain. In addition, throughout post-hoc analyses, significant differences were found in terms of perceived social support, job strain, and job insecurity. Conclusion: Work stress is an issue that compromises the safety of professional drivers. This research provides evidence supporting a significant effect of job strain on the professional driver's performance. Moreover, the statistically significant differences between taxi drivers, city bus drivers, and interurban bus drivers in their expositions to work-related stress suggest the need for tailored occupational safety interventions on each occupational group.

Effects of Augmented-Reality Head-up Display System Use on Risk Perception and Psychological Changes of Drivers

  • Hwang, Yoonsook;Park, Byoung-Jun;Kim, Kyong-Ho
    • ETRI Journal
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    • v.38 no.4
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    • pp.757-766
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    • 2016
  • This study was conducted to examine the usage effects of an augmented reality head-up display (AR-HUD) system on the risk perception and psychological changes of drivers. To do so, we conducted an experiment to collect the driver response times for vehicles and pedestrians as their risk perception behavior, and used a driving behavior determinants questionnaire consisting of Problem Evading, Benefits/Sensation Seeking, Anti-Personal Anxiety, Anti-Personal Angry, and Aggression factors for collecting the psychological characteristics of the drivers. Thirty drivers were randomly assigned into an in-vehicle AR-HUD using group and a control group. As a result, the Anti-Personal Anxiety and Anti-Personal Angry factors were negatively correlated with the response time for the control group. In contrast, these results were not shown for the in-vehicle AR-HUD system using group. These results indicate that the in-vehicle AR-HUD system may partially induce a relaxation of tension or stress for drivers with a high level of interpersonal anxiety. Therefore, the in-vehicle AR-HUD system might contribute to not only the visual safety driving behaviors of drivers, but also to their psychological driving safety with specific characteristics.

EFFECT OF LENGTH-SCALE IN DDES FOR BACKWARD-FACING STEP FLOW (후향계단 DDES 해석의 길이척도 영향 분석)

  • Lee, C.Y.;Sa, J.H.;Park, S.H.;Lee, E.S.;Lee, J.I.;Lee, K.S.
    • Journal of computational fluids engineering
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    • v.17 no.4
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    • pp.24-31
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    • 2012
  • Effects of the subgrid length-scale in the Delayed-Detached Eddy Simulation(DDES) are investigated based on the Spalart-Allmaras(S-A) and the k-$\omega$ Shear Stress Transport(SST) turbulence models. Driver & Seegmiller's experimental results are used to validate numerical results. Grid convergence with grid resolution and subgrid length-scale is investigated. The simulation results show that the volume method for the subgrid length-scale is more resistant to unfavorable effects of the grid size in the periodic direction than the maximum method. Using a sufficient grid resolution and an appropriate subgrid length-scale, both S-A based DDES and SST based DDES methods can provide a good correlation with the experimental data.

An Automated System for Constant ${\Delta}K_{eff}$ Fatigue Crack Growth Testing through Real-time Measurement of Crack Opening Load (${\Delta}K_{eff}$ 제어 피로 균열 진전 시험 자동화 시스템에 관한 연구)

  • Shin, Sung-Chul;Song, Ji-Ho
    • Proceedings of the KSME Conference
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    • 2001.06a
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    • pp.447-452
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    • 2001
  • An automated system is developed to perform fatigue crack growth tests under constant effective stress intensity factor range ${\Delta}K_{eff}$. In the system, crack length and crack opening load are measured in real-time by using the unloading elastic compliance method. The system consists of two personal computers, an analogue electrical subtraction circuit, a stepping motor, a stepping motor driver, a PIO board, and the application software used to integrate the whole system. The performance of the developed system was tested and discussed performing constant ${\Delta}K_{eff}$ crack growth tests on a CT specimen of 7075-T6 aluminum alloy. The performance of the system is found to be strongly dependent on the accuracy of measurements of crack opening load. Besides constant ${\Delta}K_{eff}$ testing, the system is expected to be successfully applied for automation of various fatigue tests.

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