• 한국자동차공학회논문집
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• 제9권4호
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• pp.148-156
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• 2001

Brake judder, one of low Sequency vibrations in brake system is determined by the excitation of Brake Torque Variation (BTV). The largest contributor to BTV is disc thickness variation. In this study, the static loads of brake torque at Suspension Mounting Points (SW) are obtained by the quasi-static analysis using DADS. The dynamic loads with frequency of BTV at SW are derived from correlation between forced vibration analysis with static loads and brake test results. And the accelerations at steering wheel were analyzed by forced vibration analysis with dynamic loads using commercial finite element program MSC/NASTRAN so that vibration characteristics of vehicle due to brake judder were investigated. Reliability of analysis results was verified through comparing the brake test results. Also, a parametric study with natural frequencies of frame, such as the 1st torsional mode and 1st bending mode, was conducted to reduce vibration amplitudes. As a result we could detect frame natural frequency conditions to improve vibration characteristics and obtained the frame model to reduce vibration amplitude.

• EDISON SW 활용 경진대회 논문집
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• 제5회(2016년)
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• pp.246-255
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• 2016

When spring of the suspension is exerted by an external load, a car should be designed to prevent predictable damages and designed for a ride comfort. We used experiments design to design VON-MISES STRESS and K, a constant, of spring of suspension which is installed in a car as a goal level. We analyzed the result from Edison's Elastic - Plastic Analysis SW(CSD_EPLAST) by setting D, d, n as external diameter of coil, internal diameter of coil, the number of total coil respectively. The experiment design let the outcome be as Full-second order by using Box-Behnken which is one of response surface methods. Experimented and analyzed results based on the established experiments design, We found out design parameter which has desired VON-MISES STRESS and the constant K. Additionally, we predicted life time of when the external load was exerted by repeated load by using fatigue equation, and verification of plastic deformation has also been made. Additionally we interpreted a model, which is formed by optimized design parameter, with linear analysis and non-linear analysis, at the same time we also analyzed plastic deformation with the values from the both models. Finally, we predicted fatigue life of optimized model by using fatigue estimation theory and also evaluated a ride comfort with oscillation analysis.

• 한국자동차공학회논문집
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• 제25권1호
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• pp.116-126
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• 2017

We suggest a process for the basic software configurations and application development in the mode management design of AUTOSAR-based ECU. Mode management is an essential task and AUTOSAR provides the mode management components for the runtime state handling of an ECU, such as BswM, application mode manager and RTE. BswM is used to meet the custom's requirements for ECU state handling. The behavior of BswM is configured with a set of rules in the form of "if-else" statements, so it is a complicated job and a potential source of errors as the number of rules increases. These difficulties can be overcome using the Model-Based Development approach, which is widely used in the AUTOSAR SW development. An efficient process is proposed to apply the MBD approach to the BswM configuration. An application mode development process is also proposed to improve the mode management design by combining the MBD process. Development tools are developed to adapt these proposed processes to the traditional ones. Simulation and experimental results are provided to prove the feasibility of the proposed approach.

• International Journal of Internet, Broadcasting and Communication
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• 제12권3호
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• pp.116-124
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• 2020

The advantage of the distance learning universities based on the 4th Industrial Revolution is that anyone can conveniently take lectures anytime, anywhere on the web. In addition, research has been actively conducted on the effect of light color and temperature control upon student performance during online classes. However, research on how the conditions of subjects, lighting colors, and music selection improve the degree of a student's concentration during online lectures has not been completed. To solve these problems in this paper, we have developed automatic analysis system SW for the weak subjects of learners by applying intelligent analysis algorithm, have proposed and simulated music therapy and art therapy. Moreover, It proposed in this paper an algorithm for an automatic analysis system, which shows the weak subjects of learners by adopting intelligence analysis algorithms. We also have presented and simulated a music therapy and art therapy algorithms, based on the blended learning, in order to increase students concentration during lecture.

• 정보과학회 논문지
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• 제43권9호
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• pp.998-1007
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• 2016

요즘 자동차 제작비용 중 차량용 전자장치에 사용되는 비용이 30% 이상을 차지하고 있다. 따라서 차량용 전자장치에 사용되는 비용 절약의 필요성이 증가하고 있다. 그런데, 완성차 업체들은 차량용 전장부품을 제작하는 일을 대부분 외주 업체에 맡기기 때문에 전장부품의 테스트 및 디버깅의 복잡도가 증가하고 있다. 이로 인해, 차량용 전장부품의 테스트 시에 발생하는 결함의 위치를 찾아내는데 많은 비용과 시간을 소비하고 있다. 이러한 문제를 해결하기 위해, 본 논문에서는 차량용 전장부품을 대상으로 통합 테스팅을 수행하는 검사자가 메모리상의 결함후보를 축소할 수 있는 기법을 제안한다. 본 기법에서는 메모리 맵을 이용하여 메모리를 분할하고, 분할된 메모리 영역에 메모리 갱신 정보를 적용해 각 분할 영역의 결함 의심도를 계산한다. 이렇게 계산된 결함 의심도를 기준으로 분할 영역들의 결함 의심순위를 결정할 수 있다. 제안하는 기법을 이용해 결함 후보 영역을 전체 메모리 크기의 1/6 정도로 축소했다.

• International Journal of Automotive Technology
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• 제8권4호
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• pp.437-444
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• 2007

This paper experimentally investigates the effects of oxygen-enriched air (OEA) on the running behaviors of an LPG SI engine during both start/warm-up (SW) and hot idling (HI) stages. The experiments were performed on an air-cooled, single-cylinder, 4-stroke, LPG SI engine with an electronic fuel injection system and an electrically-heated oxygen sensor. OEA containing 23% and 25% oxygen (by volume) was supplied for the experiments. The throttle position was fixed at that of idle condition. A fueling strategy was used as following: the fuel injection pulse width (FIPW) in the first cycle of injection was set 5.05 ms, and 2.6 ms in the subsequent cycles till the achieving of closed-loop control. In closed-loop mode, the FIPW was adjusted by the ECU in terms of the oxygen sensor feedback. Instantaneous engine speed, cylinder pressure, engine-out time-resolved HC, CO and NOx emissions and excess air coefficient (EAC) were measured and compared to the intake air baseline (ambient air, 21% oxygen). The results show that during SW stage, with the increase in the oxygen concentration in the intake air, the EAC of the mixture is much closer to the stoichiometric one and more oxygen is made available for oxidation, which results in evidently-improved combustion. The ignition in the first firing cycle starts earlier and peak pressure and maximum heat release rate both notably increase. The maximum engine speed is elevated and HC and CO emissions are reduced considerably. The percent reductions in HC emissions are about 48% and 68% in CO emissions about 52% and 78%; with 23% and 25% OEA, respectively, compared to ambient air. During HI stage, with OEA, the fuel amount per cycle increases due to closed-loop control, the engine speed rises, and speed stability is improved. The HC emissions notably decrease: about 60% and 80% with 23% and 25% OEA, respectively, compared to ambient air. The CO emissions remain at the same low level as with ambient air. During both SW and HI stages, intake air oxygen enrichment causes the delay of spark timing and the increased NOx emissions.

• 정보와 통신
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• 제29권2호
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• pp.17-22
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• 2012

기계식 장치가 주를 이루던 자동차 부품이 최근 전자제어 장치로 크게 변환되면서 차량용 소프트웨어에 대한 연구 개발 및 제품 생산도 크게 늘어나고 있는 추세이다. 자동차의 부품에 소프트웨어가 탑재됨에 따라 공통 모듈의 재 사용성, 부품 호환성 등의 문제점이 생겨나게 되었고 이를 해결하고자 하는 업계 노력의 일환으로 AUTOSAR (AUTomotive Open System Architecture) 표준이 제정된다. 본 고에서는 자동차에 탑재되는 부가 서비스 개발에 있어 기본이 되는 전자장치용 소프트웨어의 표준 플랫폼인 AUTOSAR의 동향 및 이슈에 대해서 알아 본다.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2024년도 춘계학술발표대회
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• pp.497-499
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• 2024

Fuzzing Test 와 같은 자동화된 소프트웨어 테스트 기법이 점차 출현함에 따라, 소프트웨어 테스트의 시간적 효율성과 성능의 상충을 조절하여 최적의 테스트를 진행하려는 시도가 발생하고 있다. 본 연구는 이러한 소프트웨어 테스트 기법을 하드웨어 단위에서 지원할 수 있는 기능을 확률 기반 명령어 생략 구조를 통해 제시하였다.

• 한국자동차공학회논문집
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• 제10권4호
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• pp.60-68
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• 2002

Experiments have been conducted to investigate the effects of emulsified fuels on the spray characteristics and exhaust emissions in a diesel engine. Four different fuels were examined : diesel, emulsified fuels with water contents which were varied with 13, 15, and l7wt%. Characteristics of fuel spray were measured by an optical method, PLLIF(planar liquid laser induced fluorescence). Compared to diesel fuel, emulsified fuels which had relatively high kinematic viscosity showed smaller spray angle and longer spray tip penetration. The qualitative droplet distributions of emulsified fuels showed worse atomization process than that of diesel fuel. As the water contents were increased, PM and NOx could be reduced simultaneously. It was specially noted that the emulsified fuel with l7wt% water content was found to be the best in reducing rates, NOx 30% and PM 40%.

• EDISON SW 활용 경진대회 논문집
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• 제1회(2012년)
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• pp.49-52
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• 2012

21세기인 지금 우리시대에 자동차는 필수적인 교통수단이다. 이런 자동차의 구동을 위해서는 연료가 필요하며, 아직까지 석유가 그 연료의 중심이다. 그러나 지구에서 나오는 석유자원은 매장량의 한계가 보이며, 치솟는 가격뿐만 아니라 세계적으로 고연비 고효율 차량을 선호하기 때문에 연료소비를 최소화하는 방법을 찾아야 한다. 본 연구에서는 차량의 후면 형상에 중점을 두어 주행 시 발생하는 공력특성 중 항력을 감소시키기 위해 EDISON 시뮬레이션 프로그램으로 자동차의 후면 형상 변화에 따른 공력특성 해석과 주행 시 가장 효율적인 최적의 후면 형상을 찾아보았다.