• 한국의류산업학회지
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• 제15권2호
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• pp.268-276
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• 2013

This study identifies how people use bicycle wear, complaints about bicycle wear, and functions required for bicycle riding. This survey was conducted with bicycle club members (men and women) in their twenties to sixties who ride bicycles on a regular basis. A total of 373 subjects responded to questionnaires and 326 responses were used for further data analysis. The data was analyzed by descriptive analysis, multiple response analysis, crosstabulation analysis, factor analysis, reliability analysis, and one-way ANOVA. The results are as follow: First, the people surveyed were primarily men, young adults and middle-aged people. They ride bicycles mainly to participate in club activities, to exercise, and to spend their spare time with a well-being trend that focuses on leisure and health. Second, they often utilize bicycle wear when they ride bicycles. They are aware of bicycle wear brands. In addition, a majority have purchased bicycle wear that shows a very high awareness of bicycle wear. Third, as for complaints about bicycle wear worn when riding bicycles, a majority of people answered that the waist part of the top pulls up and they feel sore with the bottom part of the pants when riding bicycles for a long time. They also answered that it is inconvenient to put belongings in both tops and pants. Fourth, there is a high demand for safety-related functions for bicycle riding in regards to the functions required for bicycle wear. In addition, a majority of the members showed a customer awareness of functional bicycle wear and intended to purchase bicycle wear equipped with smart functions.

• Smart Structures and Systems
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• 제21권5호
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• pp.705-713
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• 2018

High-speed rail (HSR) has been in operation and development in many countries worldwide. The explosive growth of HSR has posed great challenges for operation safety and ride comfort. Among various technological demands on high-speed trains, vibration is an inevitable problem caused by rail/wheel imperfections, vehicle dynamics, and aerodynamic instability. Ride comfort is a key factor in evaluating the operational performance of high-speed trains. In this study, online monitoring data have been acquired from an in-service high-speed train for condition assessment. The measured dynamic response signals at the floor level of a train cabin are processed by the Sperling operator, in which the ride comfort index sequence is used to identify the train's operation condition. In addition, a novel technique that incorporates salient features of Bayesian inference and time series analysis is proposed for outlier detection and change detection. The Bayesian forecasting approach enables the prediction of conditional probabilities. By integrating the Bayesian forecasting approach with time series analysis, one-step forecasting probability density functions (PDFs) can be obtained before proceeding to the next observation. The change detection is conducted by comparing the current model and the alternative model (whose mean value is shifted by a prescribed offset) to determine which one can well fit the actual observation. When the comparison results indicate that the alternative model performs better, then a potential change is detected. If the current observation is a potential outlier or change, Bayes factor and cumulative Bayes factor are derived for further identification. A significant change, if identified, implies that there is a great alteration in the train operation performance due to defects. In this study, two illustrative cases are provided to demonstrate the performance of the proposed method for condition assessment of high-speed trains.

• 연구논문집
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• 통권23호
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• pp.81-92
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• 1993

In this study, quarter vehicle model is used to analyse vibration control effects for ride comfort and handling safety according to this three kinds of control methods, which are the modal control, the sky-hook control and the linear viscous damping control. We performed theoretical analysis and experiments and compared two results. In experiments, electro-magnetic actuator was employed as a force actuator. It is shown that all three methods can effectively control the vehicle model. The modal control method gives similar control results using gain less than the viscous damping control.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2000년도 추계학술대회 논문집
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• pp.476-483
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• 2000

Like other vehicles, the suspension elements of railway rolling stock have influence on running stability and ride quality. Thus, faults detection for suspension elements is important to prevent an accidents of train and to ensure safety against derailment. This study was started to grasp the feasibility of diagnostic method for the suspension elements of bogie without disassembling. Through several tests by running test rig, we found that fault detection for suspension elements was possible. Here, we describe some results.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2005년도 추계학술대회 논문집
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• pp.125-130
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• 2005

The railway shall be verified with the view point of dynamic performances before delivering to the Customer and the verification procedure shall be followed the Customer's demands or relevant international standard, UIC 518 (Testing and approval of railway vehicles from the point of view of their dynamic behavior-Safety-Track fatigue-Ride quality). In this paper, verification procedures in UIC 518 and the test results for domestic project are summarized.

• 한국소음진동공학회논문집
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• 제23권12호
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• pp.1082-1089
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• 2013

3-Axis sensor measurement system is needed for measuring ride quality of elevator. But because 3-Axis piezoelectric accelerometer is expensive. We developed 3-Axis sensor system which is suitable for measuring ride quality of elevator using cheap MEMS sensor. There are two types of MEMS sensor that are piezoresistive and capacitive type. The excellence of piezoresistive type in characteristic of frequency response and noise is confirmed compare to capacitive type as a result of this paper's experiment and reference. 3-Axis system using MEMS sensor needs MEMS's proper frequency response characteristic. Additionally noise characteristic of sensor and circuit, stiffness of assembly are needed for deciding frequency range and accuracy of amplitude.

• 전기전자학회논문지
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• 제25권1호
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• pp.116-127
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• 2021

본 논문에서는 과도 상태 성능 향상이 있는 PLC와 인버터의 동시 제어기법을 제안한다. 기존 기계식 주차설비에서는 PLC만을 활용한 제어 방식이어서 유도전동기에 과전류를 발생시킬 확률이 높고, 브레이크 패드에 마찰로 인한 마모와 손상으로 승차감이 낮아지고, 수명이 단축된다. 이를 개선하기 위해서 PLC와 인버터의 동시 제어를 통한 제어 기법을 적용한 경우 유도전동기에 과전류를 방지하며 브레이크 패드를 보호하고, 승차감 향상, 제어성 상승과 안전성을 확보한다. 제안한 PLC와 인버터의 동시 제어를 통한 제어 방식을 기계식 주차설비에 적용하여 그 타당성을 검증한다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 춘계학술대회 논문집
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• pp.167-172
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• 2011

Generally, the analysis of railroad wear data is most effective method for the efficient railway maintenance. The wear of railway track affects loss of rough ride, noise or vibration of train and traveling safety. Moreover as the track is worn away, this promotes destruction of structural mechanism of rail track which can bring about increasing of rail track maintenance cost drastically. For this reason, it is very important and interested research subject to design railway track structure and to analyse train movement mechanism based on systematic analysis of the reasons causing rail wear possible in real field. In this research, for the efficient maintenance, Life Cycle Performance of rail track and maintenance characteristics are computed considering some track components such as track type, contracting type, sleeper type and roadbed type. Time - Wear probabilistic distribution relationship as well as multiple regression analysis based on time, curvature and wear data are computed to predict the service life remainder of railway track and to be adapted to safety assessment.

• 한국안전학회지
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• 제13권4호
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• pp.102-112
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• 1998

Shock absorber has a great influence on the performance of the vehicle(ride comfort, manipulation, noise, vibration, turning, stability). Therefore, in this study we consider theoretically about general damper, variable damping oil damper, the control of vehicle Characteristics for the suspension, and undesirable phenomenon. And we measured the vibration/noise characteristics of shock absorber for the real car experimentation, strain change, and noise characteristics of shock absorber using experimental equipment. The study of domestic company and research institute on the vehicle shock absorber is active, but that of basis is not. So we think that they should be accomplished actively. Therefore, this paper will develop theoretical system on the vibration/noise characteristics of shock absorber by theoretical consideration and experimental result analysis of dynamic characteristics of shock absorber that were accomplished in this study. Then we will use it as the optimistic design data for shock absorber development.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 A
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• pp.304-305
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• 2006

Now there is utilization of elevator increasing continuously, it is one of electrical facilities taking a serious view safety. However, elevator comfortable ride is researched generally Recently aging condition, equipment life, malfunction, other applicancies of power electronics and equipment disturbance effect on power quality and prevention measures are much researches in advanced nation. but awareness is lacking real condition up to now in domestic. Voltage sag, swell, harmonics, surge etc of elevator system is important problem about human safety. and there are many quality compensation to solve these problem of elevator. So to evaluate these problem, in this paper, displayed result through computer simulation for converter of problem, and inverter part by power quality problem in power distribution system.