• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1095-1098
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• 2005

Most electronic chassis control systems until today have been designed with optimization on its own performance. However, According to the increase of the interest regarding a vehicle safety and development of information technique, the integration technique of current chassis systems is being emphasized. Each enterprise proposed it with name of GCC(Global Chassis Control) or UCC(Unified Chassis Control). This study realizes control algorithm of suspension and brake by using the vehicle model of low degree of freedom as the primary stage of realization of integrated chassis control system. The proposed algorithm build the simulation environment connected to the CarSim having full vehicle model of 27 degree of freedom for raising the thrust of results

• The KIPS Transactions:PartC
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• v.18C no.1
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• pp.45-50
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• 2011

Due to advances in wireless communications and portable terminals, any-time, any-where, and any-device Internet access is possible. In particular, Internet access in moving vehicles is an emerging and challenging issue. Even though a variety studies have been conduced for vehicular networks, little attention is paid to vehicular Wi-Fi networks where a Wi-Fi access point (AP) is installed at the vehicle and the AP is connected to an external base station (BS). In this paper, we conduct a measurement study on the uplink and downlink throughput for Internet access in vehicular Wi-Fi networks. We consider diverse network environments: high-speed train, car, and subway. Measurement results demonstrate that current Internet access in vehicular Wi-Fi networks are not satisfactory for interactive multimedia applications. Therefore, in-depth study on resource management in vehicular Wi-Fi networks is strongly required.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.12 no.3
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• pp.48-53
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• 2013

An automotive air conditioning assembly consists of a condenser, a compressor and an evaporator. These major components are connected with rubber hoses and aluminum pipes. Once mounted on the automotive air conditioning assembly, it is exposed to a serious vibration environment for a long time. In some cases, there are vibration cracking on the assembly. In order to solve this vibration problem, several real vibration tests are performed on the assembly of which the lay-out was optimized, in spite of sample production cost and making time. In this study, a frequency response analysis, which is a kind of finite element method of the vibration, was performed to know the characteristic of the vibration transmission on the assembly lay-out. The analysis result indicated the damping performance, which is satisfied with the vibration standard of car maker, in rubber hoses and the whole assembly.

• The Journal of the Korea Contents Association
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• v.20 no.8
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• pp.637-644
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• 2020

VANET (Vehicular Ad Hoc Networks) is a network between vehicles and between vehicles and infrastructure. VANET-specific characteristics such as high mobility, movement limitation, and signal interference by obstacles make it difficult to provide stable VANET services. To solve this problem, this paper proposes a vehicle type-based priority clustering method that improves the existing bus-based clustering. The proposed algorithm constructs a cluster by evaluating the priority, link quality, and connectivity based on the vehicle type, expected communication lifetime, and link degree of neighbor nodes. It tries to simplify the process of selecting a cluster head and increase cluster coverage by utilizing a predetermined priority based on the type of vehicle. The proposed algorithm is expected to become the basis for activating various services by contributing to providing stable services in a connected car environment.

• Fire Science and Engineering
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• v.22 no.2
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• pp.49-56
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• 2008

Smoke propagation for the Daegu Metro fire is reproduced by a reduced-scale model experiment. The three-story station building was modeled with 1/20-scale, and the tunnel connected to the platform was not completely modeled because of its length. To include the flow resistance the tunnel provides the mesh screens were used in the model. The fire scenario was selected based on the fire growth rate of the metro car seat where the fire initiated. The time when smoke arrived at each compartment in the station building was measured by thermocouples and visualization. Regarding fire ventilation, the air supply that has been accepted as conventional design in a subway metro building intensifies smoke spread. The results show that the whole building was filled with smoke in about 10 minutes in case of no ventilation.

• Journal of Advanced Marine Engineering and Technology
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• v.23 no.3
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• pp.352-359
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• 1999

This paper is a research for removing the alternators hunting which came about during the par-allel running. The four-pole six-phase alternator is equipped with the converter made out of twelve diodes to rectify all the waves. The hunting came about during the battery charging due to the hunting inducing point existed in r. p. m band 1575[rpm-1690[rpm] To remove the hunting inducing point We modified the four-pole six-phase alternator into the four-pole twevel-phase and increased the short-circuit ratio by decreasing the field coil pitch and increasing the field coil turns. But this method has two defects the first the alternator structure becomes complicating and the second the second the alternator equipped with the converter used in general purpose lately such as the car alternator can not be run in parallel wlthout modifying. To remove the defects the equalizing line was connected between the same phase of the alterna-tor to flow the synchronizing current which syncronize the phases of generator electromotive forces by which the alternator can be run in parallel without reference to the hunting inducing point and without modifying.

• Proceedings of the KIEE Conference
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• 2001.11b
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• pp.153-156
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• 2001

The transformer and the OF cable are cooled and insulated by insulating oils in their body. The insulating oil expands or contracts with the heat transfer according to the operating conditions of the electric facilities. So we install the $N_2$ gas tank connected with the insulating oil system to overcome the change. The change of the insulating oil volume for the operation temperature range must be calculated to decide the $N_2$ gas volume and to set the alarm point for safe operation. It is known that this change is proportional to the temperature change and to the insulating oil volume if the temperature change is small enough.[1][11] However this proportional formula has been accepted generally in the design of electric facilities for wide operation temperature range such as $40^{\circ}C{\sim}125^{\circ}C$. Hence, it makes large errors in calculation which car result in serious damage against safe operation of the electric facilities. This paper presents a improved method of calculating the accurate change of the insulating oil volume to insure the safe operation of electric facilities.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.12
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• pp.2785-2792
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• 2013

An elevator is driven by the friction between the pulley and wire rope. A balancing counter weight is connected to the elevator car with a wire rope. This structure is essential to drive elevators while it always has weight unbalance problems on each side. The overbalance-ratio of elevators may be an important factor for safety and structural efficiency; however, it is not yet clearly defined in the Requirements of Korea Elevator Inspection. This paper describes these "weight unbalance ratio" for control of elevators to reduce the number of accidents. It includes the analysis of current elevator maintenance situations and also proposes some fundamental improvement schemes for safety.

• Proceedings of the Korea Information Processing Society Conference
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• 2018.10a
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• pp.253-256
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• 2018

최근 4차 산업혁명은 기존에 한정적이던 사물들의 역할을 끝없이 확장시키는 특징을 가진다. 인터넷을 기반으로 인간, 사물, 환경 등 모든 것은 연결이 가능한 Internet of Things(IoT) 시대가 다가오고 있다. 사람과 사물, 사물과 사물 간의 정보를 상호 소통하여 안전기능과 사용자의 편의성을 향상시키고 있으며, ICT의 융복합의 발전에 따라 자동차도 기존과 다르게 IoT 환경에 포함된다. 커넥티드 카는 차량, 인프라, 모바일 디바이스, 주변 환경 간의 통신을 통해 실시간으로 다양한 정보를 자동차를 중심으로 수집할 수 있게 되었으며 이를 기반으로 커넥티드 카 산업이 발전하고 있다. 그러나 이러한 발전 과정 속에서 커넥티드 카의 보안성의 문제는 반드시 해결되어야 한다. 보안성이 확보되지 않는다면, 자동차에서 발생하는 운전자에 대한 악의적인 공격을 통해 일반적인 보안 침해사고 수준을 넘어 사고를 유발시킬 경우 인명과 재산상의 큰 피해를 발생시킬 수 있다. 본 논문에서는 커넥티드 카의 통신구조를 알아보고 취약점 분석과 이에 대한 대응 방안을 제안하여 안전한 커넥티드 카의 활용 방안을 연구한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2019.05a
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• pp.118-120
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• 2019

커넥티드카는 네트워크에 연결된 자동차가 다른 자동차 및 도로 인프라뿐만 아니라 스마트 디바이스와 통신하고 여러 소스로부터 실시간 데이터를 수집하여 다양한 서비스를 제공하는 것이다. 커넥티드카의 등장으로 인해서 자동차와 클라우드 서비스의 결합이 빠르게 진행되고 있으나 자동차 데이터 중 실시간 처리가 필수인 데이터가 많다는 특성이 있다. 그러므로 멀리 떨어진 중앙 집중식 서버에서 컴퓨팅을 하는 클라우드 컴퓨팅보다 최근 이슈가 되고 있는 디바이스와 가까운 가장자리에 위치한 서버에서 컴퓨팅을 하는 엣지 컴퓨팅이 커넥티드카의 실시간성을 보장하는 기술로 많은 관심을 받고 있다. 본 논문에서는 기존의 엣지 컴퓨팅과는 달리, 이동성이 있는 모바일 엣지 컴퓨팅(MEC) 환경에서 실시간 처리를 저해하는 요소를 찾아 원인을 분석하고 평가해 문제점을 해결하고자 한다. 먼저, MEC 환경을 구축한 후 오픈 소스 시뮬레이터인 Edge Cloudsim 에 적용시켜 시뮬레이션을 한다. 실험 결과 MEC 환경에서 실시간 처리를 저해하는 원인은 모바일 디바이스의 태스크가 오프로딩 되거나 응답을 받기 전 WLAN 의 범위를 벗어났을 때 Task Failure가 발생하기 때문임이 증명되었다.