• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2002.05a
• /
• pp.670-673
• /
• 2002

Automotive wheel bearings are one of the most important components to guarantee the service life of a passenger car. The endurance life of a bearing is affected by many parameters such as material properties, heat treatment, lubrication conditions, temperature, loading conditions, bearing geometry, internal clearance and so on. In this paper, we analyze the relation between loads and deformations of wheel bearing units. On the basis of it we calculate the endurance life of wheel bearing units and analyze the contribution of bearing geometric parameters on the endurance life by using Taguchi method.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2005.06a
• /
• pp.468-472
• /
• 2005

This paper is to investigate the influence of the endface quality on the loss characteristics of a plastic optical fiber connector for in-car network service. Using the parameters of the surface roughness and applied load, insertion loss of connector is measured. Due to scattering and change of refractive index, an optimal condition for low-loss coupling exists. We present the optimal condition as surface roughness $R_{rms}$ = 8 nm and contact load up to 50 N.

• Journal of the Korean Society for Precision Engineering
• /
• v.23 no.3 s.180
• /
• pp.61-68
• /
• 2006

This paper is to investigate the influence of the endface quality on the loss characteristics of a plastic optical fiber(POF) connector and the stability of new designed sleeve for in-car network service. Using the parameters of the surface roughness and applied load, insertion loss of connector is measured. Endface condition for optimizing the connection is presented by the surface roughness satisfying loss criteria and the stress for minimizing the loss, $R_{rms}=8nm$ and 19 MPa, respectively. By vibration test and dynamic loss measurement, we show the stability of the new designed sleeve.

• Journal of the Korean Society for Precision Engineering
• /
• v.17 no.2
• /
• pp.51-57
• /
• 2000

An automotive wheel bearing is one of the most important components to guarantee the service life of a passenger car. The endurance lift of a bearing is affected by many parameters such as material properties, heat treatment, lubrication conditions, temperature, loading conditions, geometry, internal clearance and so on. Under the same geometry and loading conditions, the internal clearance is the most effective parameters on the endurance lift of a bearing. Generally, bearings have the longest lift with a little negative internal clearance. But it is very difficult to measure and modify the internal clearance after a wheel bearing is assembled. In this paper, we analyze the effect of an assembling procedure on the clearance of wheel bearings and suggest a method to determine optimal clearance for automotive wheel bearings by selecting initial bearing clearance.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2004.10a
• /
• pp.1323-1326
• /
• 2004

A bogie frame of welded type have some problems. Some end beam has cracked. The cracks have profound influence on the safe freight service. The bogie consists of a frame, suspensions, brakes and wheel sets. Various analyses including a numerical simulation using a finite element method, a static load test, a fatigue test, and running test should be carried out to design the bogie. However cracks have been found at some end beams of the bogies mounted on the freight cars running with the high speed. The cracks of the end beam results in deterioration of the brake performance and the running safety. Numerical simulations and dynamic tests are carried out to figure out the causes of cracks in the existing bogie, and the vibrational characteristics of the improved bogie are compared with those of the conventional one. In this reports, the vibration characteristics were dealed with the most pressing matters for the solution of the end beam crack.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2017.04a
• /
• pp.466-468
• /
• 2017

카 쉐어링 서비스는 경제위기 이후 실용적 소비패턴 의식의 확산과 환경의식의 고취, 스마트폰 확산을 통한 서비스 이용 편의성이 증가됨으로 인해 새로운 대중교통으로 자리매김을 하고 있다. 시장이 발전하고 많은 사람들이 이용하면서 다양한 카 쉐어링 업체들이 생겨나고 있다. 또한 각 업체들에서 사용하는 인증방식은 단순 ID/PW 로그인 방식이기 때문에 보안에 취약하다. 본 논문에서 제안하는 모델은 차량의 데이터가 등록되어 있는 다양한 업체들의 클라우드를 클라우드 서비스 브로커를 통해 사용자들에게 편리성을 제공하고 바이오정보를 이용하여 더욱 강력한 인증을 통해 안전한 서비스를 제공하고자 한다. 본 논문에서 제안한 모델을 통해 안전한 토인과 사용자의 편의성이 증대되기를 기대한다.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.15 no.5
• /
• pp.160-164
• /
• 2007

An automotive wheel bearing is one of the most important components to guarantee the service life of a passenger car. The endurance life of a bearing is affected by many parameters such as material properties, heat treatment, lubrication conditions, temperature, loading conditions, bearing geometry, internal clearance and so on. Generally, a tapered roller bearing gives longer endurance life than that of an equivalent size ball bearing. Consequently, the application of taper bearing units will be increased for more compact design and extended warranty. In this paper, we derive the relation between loads and deformations of a taper bearing unit. On the basis of that, we calculate the endurance life of the taper bearing unit considering initial axial clearance.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.25 no.12
• /
• pp.94-100
• /
• 2011

TCMS is the most important controller in the subway train for reliable train control and service oriented flexibility. TCMS software charges communications and control of train and maintains control devices so we use QNX for real-time control. This paper introduces overall software development of TCMS using various diagrams. Software implementation details in TC and CC are explained using deployment diagram through train configuration. Driving control process among many processes is focused to present implement details which controls train by driver or automatic train operation and handles commands to control deriving devices in cars. Reliable operation of train and easy maintenance process is achieved through the same hardware in train control computer and car control computer.

• Journal of the Korean Operations Research and Management Science Society
• /
• v.36 no.1
• /
• pp.27-38
• /
• 2011

In this paper, we deal with the periodic heterogeneous fleet vehicle routing problem (PHVRP). PHVRP is a problem of designing vehicle routes in each day of given period to minimize the sum of fixed cost and variable cost over the planning horizon. Each customer can be visited once or more times over the planning horizon according to the service combinations of that customer. Due to the complexity of the problem, we suggest a heuristic algorithm in which an initial solution is obtained by assigning the customer-day and the customer-car simultaneously and then it is improved. A performance of the proposed algorithm was compared to both well-known results and new test problems.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.13 no.4
• /
• pp.1857-1862
• /
• 2012

It is very difficult to construct and manager public transit, like subway, in small city. In this paper, we suggest full electric vehicle sharing service framework as a public transit system in small city. The suggested system will reduce environment pollution and increase resource usage efficiency. The simulation result shows that the suggested electric vehicle sharing system can reduce traffic congestion and lower city road stress.