• 한국자동차공학회논문집
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• 제14권6호
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• pp.143-150
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• 2006

In this paper, a new bushing model for vehicle dynamics analysis using Bouc-Wen hysteretic model is proposed. Bushing components of a vehicle suspension system are tested to capture the nonlinear behavior of rubber bushing elements using the MTS 3-axes rubber test machine. The results of the tests are used to define parameters in Bouc-Wen bushing model, which was employed to represent the hysteretic characteristics of the bushing. Bushing parameters are obtained by using genetic algorithms and sensitivity analysis of parameters are also carried out. ADAMS program was used for the identification process and VisualDOC program was employed to find the optimal parameters. A half-car simulation was carried out to show the usefulness of the developed bushing model.

• International Journal of Computer Science & Network Security
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• 제21권8호
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• pp.55-64
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• 2021

In the last few years, the massive development in wireless networks, high internet speeds and improvement in car manufacturing has shifted research focus to Vehicular Ad-HOC Networks (VANETs). Consequently, many related frameworks are explored, and it is found that security is the primary issue for VANETs. Despite that, a small number of research studies have taken into consideration the identification of performance standards and parameters. In this paper, VANET security frameworks are explored, studied and analysed which resulted in the identification of a list of performance evaluation parameters. These parameters are defined and categorized based on the nature of parameter (security or general context). These parameters are identified to be used by future researchers to evaluate their proposed VANET security frameworks. The implementation paradigms of security frameworks are also identified, which revealed that almost all research studies used simulation for implementation and testing. The simulators used in the simulation processes are also analysed. The results of this study showed that most of the surveyed studies used NS-2 simulator with a percentage of 54.4%. The type of scenario (urban, highway, rural) is also evaluated and it is found that 50% studies used highway urban scenario in simulation.

• 디지털산업정보학회논문지
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• 제13권1호
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• pp.69-78
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• 2017

As the smartphone-based devices are diffused and developed rapidly, they provide the convenience to the users. The abovementioned sentence technologies are being used not only in the existing sensor and wireless network technology but also in the application services of the diverse fields application services such as smart appliance, smart car, smart health care, etc. and the new fusion paradigm from the industry is presented by undertaking the researches in diverse area by the enterprises and research institutions. However, the smart environment exposes its weaknesses in the mobile terminal area, existing wireless network and IT security area. In addition, due to new and variant ways of attack, not only the critical information are disclosed However also the financial damages occur. This paper proposed the protocol to perform the smartphone-based safe device monitoring and safe communication. The proposed protocol designed the management procedure of registration, identification, communication protocol and device update management protocol and the safety against the attack techniques such as the an-in-the-middle-attack, impersonation attack, credential threat, information leaks and privacy invasion was analyzed. It was observed that the proposed protocol showed the performance improved by approximately 52% in the communication process than the existing system.

• 한국지능시스템학회논문지
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• 제7권4호
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• pp.29-39
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• 1997

A discrete model reference control scheme for a vehicle four wheel steering system(4WS) is proposed and evaluated for a class of discrete time nonlinar dynamics. The schmen employs a neural network to identify the plan systems, wher the neural network estimates the nonlinear dynamics of the plant. The algorithm is proven to be globally stable, with tracking errors converging to the neighborhood of zero. The merits of this scheme is that the global system stability is guaranteed. Whith thd resulting identification model which contains the neural networks, the parameters of controller are adjusted. The proposed scheme is applied to the vehicle active four wheel system and shows the validity and effectiveness through simulation. The three-degree-of freedom vehicle handling model is used to investigate vehicle handing performances. In simulation of the J-turn maneuver, the yaw rate overshoot reduction of a typical mid-size car is improved by 30% compared to a two wheel steering system(2WS) case, resulting that the proposed scheme gives faster yaw rate response andl smaller side slip angle than the 2WS case.

• 한국소음진동공학회논문집
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• 제21권9호
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• pp.787-797
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• 2011

The noise in a vehicle is an important factor for customers purchasing a car. Particularly, reduction of the noise that is generated from HVAC(heating, ventilation and air conditioning) is very important since it has considerable effects on interior noise. In general, identification of noise source is crucial to reduce noise level. The complex acoustic intensity method is widely used to obtain the accurate measurement and identification of noise source. Therefore, in the previous study, noise source of HVAC was identified through experimental approach using the complex acoustic intensity method. In this study, we are intended to confirm reduced level of noise by comparing the result between before and after modification of cam curve that is based on identified noise source of HVAC. It is found out that noise source of HVAC are motor and cam area using the complex acoustic intensity method in the previous study. We performed experiments to compare noise level between before and after modification of cam curve. Especially, it can be seen that complex acoustic intensity method using both active and reactive intensity is vital in devising a strategy for comparison to noise level. Also, the vector flow of acoustic intensity was investigated to identify sound intensity distributions and energy flow in the near field of HVAC.

• International Journal of Automotive Technology
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• 제8권1호
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• pp.75-82
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• 2007

This paper presents practical work on the reduction of gear whine noise. In order to identify the source of the gear whine noise, transfer paths are searched and analyzed by operational deflection shape analysis and experimental modal analysis. It was found that gear whine noise has an air-borne noise path instead of structure-borne noise path. The main sources of air-borne noise were the two global modes caused by the resonance of an axle system. These modes created a vibro-acoustic noise problem. Vibro-acoustic noise can be reduced by controlling the vibration of the noise source. The vibration of noise source is controlled by the modification of structure to avoid the resonance or to reduce the excitation force. In the study, the excitation force of the axle system is attenuated by changing the tooth profile of the hypoid gear. The modification of the tooth profile yields a reduction of transmission error, which is correlated to the gear whine noise. Finally, whine noise is reduced by 10 dBA.

• 한국건설관리학회:학술대회논문집
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• 한국건설관리학회 2008년도 정기학술발표대회 논문집
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• pp.922-925
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• 2008

Many highway projects are under way in Korea. However, owners frequently find that the project cost exceeds the budget and they are unable to identify the underlining reasons. The main purpose of this research is to develop cost models for transportation projects in Korea using the multiple linear regression (MLR). The data consist of 27 completed transportation projects, built from 1991 to 2001, The technique of multiple regression analysis is used to develop the parametric cost estimating model for total budget cost per highway square meter (TBC/$m^2$). Findings of the study indicated that MLR car be applied to highway projects in Korea. There are twf) major contributions of this research. (1) the identification of transportation parameters as a significant cost driver for transportation costs and (2) the successful development of the parametric cost estimating models for transportation projects in Korea.

• 한국정보통신학회논문지
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• 제25권12호
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• pp.1762-1769
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• 2021

본 연구의 최종 목표는 블랙박스, 스마트폰, CCTV 등으로부터 수집된 영상에서 수배차량이 범죄차량인지 여부를 분석할 수 있는 시스템을 개발하는 것이다. 데이터 수집은 자체 개발된 블랙박스를 이용하였다. 본 연구에 활용된 데이터는 차량 유형 8개(트럭, RV, 승용차, 승합차, SUV, 버스, 스포츠카, 전기차)와 차량 모델 434개 등 총 83,753건의 데이터를 사용하였다. YOLO v5를 이용한 차량인식 결과, mAP가 80%로 나타났다. 자체 개발한 블랙박스를 이용하여 ReXNet으로 차량 모델을 식별한 결과, 정확도는 99%로 나타났다. 이러한 결과는 데이터 라벨링의 정확도를 개선하는 것이 차량인식 성능 향상에 도움이 된다는 것을 의미한다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2010년도 춘계학술대회 논문집
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• pp.2095-2106
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• 2010

In this study, to grasp the stability of train and to identify the track irregularity, the algorithm was proposed. As the track deformation occur due to running train, the dynamic characteristics of train show non-linearity. The representative transfer functions of wheel to car response were calculated from the frequency response functions which were estimated from measured triaxial accelerations. The measured acceleration responses were compared with the estimated responses from filtered acceleration outputs. This result could show the non-linearity of train system at the location of track deformed. The proposed algorithm was verified by matching with the site investigation.

• 한국ITS학회 논문지
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• 제15권3호
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• pp.23-33
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• 2016

본 연구는 SUR모형을 활용하여 서울 거주자의 수단별 통행시간 비율에 대한 영향요인을 규명하였다. 영향요인은 가구원 및 가구의 특성, 존 특성 변수 등을 선정하였다. 통행수단은 기존의 18개 유형을 압축하여 도보, 개인통행수단, 버스, 지하철, 철도, 자전거 등 6개 수단으로 재 정의하였다. 분석 결과, 개인교통수단과 대중교통간의 뚜렷한 차이를 발견하였다. 우선 차량을 보유하고 운전면허가 있는 경우에는 개인통행수단을 이용하는 경향이 강한 것으로 나타났다. 이와 함께 대표적인 대중교통 수단인 버스와 지하철간의 상관관계를 파악할 수 있었다. 지하철 수단은 개인통행수단이 이용 가능한 통행자가 함께 이용하는 패턴을 보인 반면, 버스 수단은 개인통행수단 이용이 어려운 경우에 이용하는 경향을 보였다. 이러한 선호도는 향후 서울을 포함한 수도권의 대중교통 정책을 수립함에 있어 다양한 시사점을 제시할 수 있을 것으로 기대한다.