• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 춘계학술대회 논문집
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• pp.1546-1549
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• 2007

A ride quality measurement was carried out for commuter and express train used in airport railway. Lateral and vertical directional average ride quality level is higher than that of longitudinal direction. Because express train is faster than commuter train, the average ride quality level of express train is higher compared to that of commuter train. The average ride quality level of commuter train is between 'good comfortable($100{\sim}105dB$)' and 'very good comfortable(below 100dB)'. The average ride quality level of express train is between 'not comfortable($105{\sim}110dB$)' and 'good comfortable($100{\sim}105dB$)'. In spite of the scheduled speed is higher(more than 70km/h for commuter train, more than 80km/h for express train) than other lines, the ride quality of airport railway train is good. The reason is that there is little gradient in rail and the radius of curvature is larger compared to that of other lines.

• Journal of Mechanical Science and Technology
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• 제19권7호
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• pp.1469-1477
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• 2005

Vibrations related to ride comfort should be considered at the beginning of design stage. In general, ride comfort of human is mainly affected by vibration transmitted from the floor and seat. Also, vibration level is very important regarding with running safety on freight wagon. To ensure ride comfort for passenger coach and vibration level for freight wagon, tests had been repeated by different test procedures with several equipments. With different measuring and evaluations for these results, it took much time to evaluate test results. In this paper, a new evaluation procedure was developed combining several software for ride comfort and vibration level test on railway vehicles. In addition, this developed system is capable of ride comfort test and vibration test by a single integrated system that is capable of immediate reporting the test result. With this developed system, the comfort in a passenger coach and the vibration in a freight car were evaluated. And the simulation results from the proposed system are verified by a field test.

• Journal of Biosystems Engineering
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• 제29권3호
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• pp.207-216
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• 2004

This study was intended to investigate the characteristics of ride vibrations transmitted to tractor operator during rotary tillage and plowing operations. Seat accelerations of a 41 ps diesel tractor in rotary tillage and plowing were measured and evaluated as specified in the ISO 2631-1. Effects of working speed and tilling depth on ride vibration were investigated. The level of ride vibration was also evaluated in terms of health guidance caution zones. Some of the results of the study are as follows: 1. The level of ride vibration in plowing was about 4.3 times greater than in rotary tillage. 2. The effect of working speed in rotary tillage differs depending upon the tillage depth. The level of ride vibration was increased with the speed, but it decreased over a certain tillage depth. Fore and aft vibration was 2.2-2.7 times severer than horizontal and vertical vibrations. Dominant frequency band was 1-3.15 ㎐ in fore and aft, 1-3.15㎐ and 16-25㎐ in horizontal, and 16-25㎐ in vertical directions. 3. Plowing reduced the ride vibration by 42.8-50.2%. But its positive effect decreased as the plowing speed increased. In plowing operation, ride vibration was similar degrees in fore and aft, horizontal and vertical directions. The dominant frequency band in plowing operation was 1-2.5㎐ in fore and aft, 1-2.5㎐ in horizontal, and 1-8㎐ in vertical directions. 4. On a basis of daily work hours of 4, total level of ride vibrations in plowing operation is likely to be harmful to operator's health.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2012년도 추계학술대회 논문집
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• pp.959-960
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• 2012

• 대한인간공학회지
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• 제32권4호
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• pp.389-396
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• 2013

Objective: The ride qualities of the six passenger cars were evaluated in 4 subjects on the highway and uneven road. The relation between vibration with driving velocity and driving posture were also investigated separately. Background: Ride comfort plays an important role in the vehicle design. Vibration is the one of the principal components associated with ride comfort. Method: The acceleration of the foot, hip and back were measured using B&K accelerometers in this study. The velocity of the passenger cars was maintained at a constant speed of 80km/h on the highway and 40km/h on the uneven road. For evaluating the effects of driving velocity and driving posture on vehicle's vibration level, separate experiments were performed on the highway with 5 different vehicle speeds and 5 different backrest angles, respectively. Results: The overall ride value of the luxury car showed the best result while the smaller car showed the worst value on the highway. On the uneven road the overall ride value level was increased 75~98%. All the vehicles had the SEAT value less than 1. Faster the velocity lowers the SEAT value. The ride quality in terms of vibration gets worst when the backrest angle increased. Conclusion: The smaller car had a first mode at the higher frequency and showed higher vibration level. SEAT value was mostly affected by the seat property not by vehicle. We ranked the luxury car seat had a best vibration reduction quality than others based on SEAT values. When the driving velocity increased, the overall ride values were increased proportionally and the SEAT values were somewhat decreased. Application: Evaluation of whole-body vibration in the passenger car.

• 한국철도학회논문집
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• 제6권2호
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• pp.114-121
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• 2003

In this paper, a new evaluation system was developed for ride comfort test and vibration level test on railway vehicles. These tests are carried out by applying different equipments and test procedures before now. But this developed system is capable of ride comfort test and vibration test by a single integrated system. Also, the evaluation algorithm for the ride comfort was compared and verified by simulation results with VAMPIRE software. With this developed system, the comfort in a passenger coach and the vibration in a freight car were verified by the results in field test.

• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 2001년도 동계 학술대회 논문집
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• pp.16-21
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• 2001

The ride quality of agricultural tractor seats is evaluated based on the vibration of the human bodies. Tractor ride vibration levels have been measured at the person-seat interface along 7 axes(3 translational axes at the feet, 3 translational axes on a seat surface and 1 axis at the seat back), under different operating conditions. Since one of the most important parameters for ride comfort is the level and duration of the root mean square acceleration experienced, the ride values, such as the seat effective amplitude transmissibility, the component ride value, and the overall ride value based on acceleration root mean square are evaluated for a conventional tractor using frequency weighting functions and axis multiplying factors. The ride indices are also studied considering to the variation of vehicle speed and road profile.

• 한국정밀공학회지
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• 제29권6호
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• pp.593-599
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• 2012

To analyze the effect of the track structure on the running performance of the railway vehicle, we studied on the vibration and ride characteristics of the high speed train. As results, vibration and ride level of high speed train on the concrete bed track is more reduced than on the ballast bed track. Peak-peak value of carbody vibration on the concrete bed track at 300km/h is half of the peak-peak value of carbody vibration on the ballast bed track. Ride level on the concrete bed track at 300km/h is same level as that on the ballast bed track at 250km/h. Thus, Vibration and ride performance of the high speed train on the concrete bed track is greatly improved compared with that on the ballast bed track.

• 한국응급구조학회지
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• 제19권3호
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• pp.87-101
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• 2015

Purpose: The purpose of this study was to provide an appropriate direction for an effective field practice program by analyzing the factors related to practical procedures in the ambulance ride practice of paramedic students in Korea. Methods: Questionnaires were answered by 202 paramedic students from March 28 to April 15, 2014. The collected data were analyzed with SPSS WIN 18.0 program. Results: The general level of procedural exposure during ambulance ride practice was 59.0% on average. Considering the practice of specific areas, vital sign checking, patient assessment, and oxygen supply showed relatively high percentages of 92.3%, 77.4% and 72.6%, respectively, whereas the areas of fluid and drug, airway, and cardiopulmonary resuscitation recorded relatively low percentage of 25.8%, 24.1% and 50.2%, respectively. The level of direct practice was significantly high in the group that included the largest number of paramedics. Conclusion: For an effective field practice, the place of practice needs to have various cases of patients to ensure a wide experience of procedures during the practice, and ambulance workers with a high level of expertise should be selected to ride with students.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 춘계학술대회논문집
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• pp.911-916
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• 2005

Noise map is a presentation of existing data or predicted noise situation in terms of noise indicator. However, it has shortcoming for assessing the number of people exposed, or the number of dwellings affected to any relevant limit values of noise level in certain areas. In this study, so called over-ride value noise mapping is proposed to make up for the shortcoming by using over-ride function of object-oriented programming and it is to show the guard of the area where it is satisfied the standard of option, or it is not satisfactory. Over-ride value noisemap data is combined with topography layer, population and house statistics, and GIS space statistical analysis. The over-ride value noise mapping can also he applied to make the road traffic noisemap, the railroad noisemap, the aircraft noisemap, and the industrial site noisemap This can express noise damage information more exactly.