• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.9 no.5
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• pp.213-224
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• 2009

This paper presents a new algorithm for estimating a driver's physical condition using real-time vision system and performs experimentation for real facial image data. The system relies on a face recognition to robustly track the center points and sizes of person's two pupils, and two side edge points of the mouth. The face recognition constitutes the color statistics by YUV color space together with geometrical model of a typical face. The system can classify the rotation in all viewing directions, to detect eye/mouth occlusion, eye blinking and eye closure, and to recover the three dimensional gaze of the eyes. These are utilized to determine the carelessness and drowsiness of the driver. Finally, experimental results have demonstrated the validity and the applicability of the proposed method for the estimation of a driver's physical condition.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2009.04a
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• pp.681-688
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• 2009

This paper deals with a bearing faults localization technique based on holographic approach by visualizing sound radiated from the faults. The main idea stems from the phenomenon that bearing faults in a moving vehicle generate impulsive sound. To visualize fault signal from the moving vehicle, we can use the moving frame acoustic holography [H.-S. Kwon and Y.-H. Kim, "Moving frame technique for planar acoustic holography," J. Acoust. Soc. Am. 103(4), 1734-1741, 1998]. However, it is not easy to localize faults only by applying the method. This is because the microphone array measures noise (for example, noise from other parts of the vehicle and the wind noise) as well as the fault signal while the vehicle passes by the array. To reduce the effect of noise, we propose two ideas which utilize the characteristics of fault signal. The first one is to average holograms for several frequencies to reduce the random noise. The second one is to apply the partial field decomposition algorithm [K.-U. Nam, Y.-H. Kim, "A partial field decomposition algorithm and its examples for near-field acoustic holography," J. of Acoust. Soc. Am. 116(1), 172-185, 2004] to the moving source, which can separate the fault signal and noise. Basic theory of those methods is introduced and how they can be applied to localize bearing faults is demonstrated. Experimental results via a miniature vehicle showed how well the proposed method finds out the location of source in practice.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.2 no.4
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• pp.11-21
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• 1982

The dynamic strain-time(${\varepsilon}$-t) curves of the fatal members in three existing steel railway bridges was measured during the selected trains was passing, and was regulated statistically. By the results of these the equivalent fatigue damages of the selected members was calculated in comparison with the allowable stresses, and was examined. From these the base available in evaluating the stability and the lifeproof of the steel railway bridge was obtained. In addition to this, the following several properties which could be used availably in designing the steel railway bridges. It was conformed that the fatigue damages was different each other even in the same members, if the unit weight of the trains was same but the weights and the dispositions of the wheels of the trains was different each other. It was indicated that the fatigue damages was larger in the members which had the defects in components of the materials, the flaws being made during producing and constructing, and the corrosions, etc. It was considered that more a vailable data could be obtained, if the same studies were continued under the spans and the types of the bridges being changed continuously.

• Journal of Korean Society of Transportation
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• v.30 no.5
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• pp.61-69
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• 2012

It is important for highway maintenance and safety assessment to get the accurate highway geometric information. However, it is difficult to acquire good highway geometric information due to missing blueprints or deteriorated highway sections. This research, to get highway geometric information rapidly, has developed a highway geometric analysis algorithm that uses data from vehicles with GPS-IMU integrated system. In conclusion, the result shows that 3.38% of error-ratio for the horizontal alignment and 0.083 absolute value difference for vertical grade comparing with highway drawings. Therefore, the result suggest that the developed method can be applied to the road safety inspection or road safety audit.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.2
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• pp.1-7
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• 2016

Although the second driving device of KTX, which consists of the wheel and the axle reduction gears unit, is a mechanically integrated structure, its preventive maintenance (PM) requires two separate intervals due to the different technical requirements. In particular, these subsystems perform attaching and detaching work simultaneously according to the maintenance directive. Therefore, to reduce the unnecessary amount of PM and high logistic availability of the train, it is important to optimize PM with regard to reliability-centered maintenance toward a cost-effective solution. In this study, fault tree analysis and reliability of the subsystems, considering the criticality of the components, were performed using the data derived from field data in maintenance. The cost optimization of the PM was derived from a genetic algorithm considering the target reliability and improvement factor. The cost optimization was derived from a maximum of the fitness function of the individual in generation. The optimal TBO of them using the genetic algorithm was 2.85x106 km, which is reduced to approximately 21% compared to the conventional method.

• Proceedings of the KWS Conference
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• 2009.11a
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• pp.8-8
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• 2009

알루미늄 합금 Al 6082-T6는 최근에 개발되어 북유럽 등의 선진국에서는 그 뛰어난 해양 내식성과 우수한 강도로 인하여 해양구조물의 헬리데크(Helideck), 타워 갱웨이(Tower gangway), 알루미늄 피팅류(Aluminium fitting)등의 해양구조물과 플랫폼(Flatform), 알루미늄 래더(Aluminium ladder)등의 선박부품, 차량, 기계부품 분야에서 전 세계적으로 널리 사용되기 시작하였다. 그러나 전통적으로 용접금속의 기공은 결함으로 분류 되고, Rakesh Kumar 등의 논문에 따르면 용접 시 용접금속 내에 발생되어진 미세기공이 기계적 성질에 악영향을 미치는 것으로 보고되어졌다. 따라서 용접금속내의 발생하는 기공을 방지하는 용접공정의 개발이 반드시 필요하다. 본 연구의 목적은 Al 6082-T6 고속 MIG용접에서 기공방지를 위한 용접공정을 개발하는 것이다. Al 6082-T6의 7t 플레이트에 Al 5356의 와이어를 사용하여 아크길이 변경 및 용접속도를 60cpm과 120cpm으로 변경하여 실험하였고, 용접속도 120cpm의 고속 MIG용접에서 토치 진행각을 변경하여 실험을 진행하였다. 용접공정 파라메터 변경에 따른 기공율 측정은 이미지 분석 소프트웨어를 사용하여 정량적으로 분석하였다.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.17 no.6
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• pp.224-239
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• 2018

Autonomous vehicles can significantly reduce accidents due to 'driver's carelessness', which occupies the majority of causes for traffic accidents, but they may fail to avoid traffic accidents due to unexpected situations, such as "trolley dilemma", vehicle defects and road defects. Therefore in situations Autonomous vehicles need to be made ethical choices. This study assumes that Autonomous vehicles can not avoid traffic accidents due to unexpected sink holes. In this situation, the traffic accident costs was analyzed for the ethical choices of Autonomous vehicles. In the process, Autonomous vehicles were made to choose one of three ethical choices : (1) Egoism with priority on passenger safety, (2) Deontology for minimizing human damages, (3) Utilitarianism with minimizing traffic accident costs. As a result of the analysis, egoism had the highest traffic accident costs, and deontology for minimizing human damages had the lowest traffic accident costs.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.46 no.2
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• pp.72-81
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• 2023

This research proposes a novel approach to tackle the challenge of categorizing unstructured customer complaints in the automotive industry. The goal is to identify potential vehicle defects based on the findings of our algorithm, which can assist automakers in mitigating significant losses and reputational damage caused by mass claims. To achieve this goal, our model uses the Word2Vec method to analyze large volumes of unstructured customer complaint data from the National Highway Traffic Safety Administration (NHTSA). By developing a score dictionary for eight pre-selected criteria, our algorithm can efficiently categorize complaints and detect potential vehicle defects. By calculating the score of each complaint, our algorithm can identify patterns and correlations that can indicate potential defects in the vehicle. One of the key benefits of this approach is its ability to handle a large volume of unstructured data, which can be challenging for traditional methods. By using machine learning techniques, we can extract meaningful insights from customer complaints, which can help automakers prioritize and address potential defects before they become widespread issues. In conclusion, this research provides a promising approach to categorize unstructured customer complaints in the automotive industry and identify potential vehicle defects. By leveraging the power of machine learning, we can help automakers improve the quality of their products and enhance customer satisfaction. Further studies can build upon this approach to explore other potential applications and expand its scope to other industries.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.3
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• pp.669-678
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• 2018

This study developed information technology infrastructures for building a driving environment analysis platform using various big data, such as vehicle sensing data, public data, etc. First, a small platform server with a parallel structure for big data distribution processing was developed with H/W technology. Next, programs for big data collection/storage, processing/analysis, and information visualization were developed with S/W technology. The collection S/W was developed as a collection interface using Kafka, Flume, and Sqoop. The storage S/W was developed to be divided into a Hadoop distributed file system and Cassandra DB according to the utilization of data. Processing S/W was developed for spatial unit matching and time interval interpolation/aggregation of the collected data by applying the grid index method. An analysis S/W was developed as an analytical tool based on the Zeppelin notebook for the application and evaluation of a development algorithm. Finally, Information Visualization S/W was developed as a Web GIS engine program for providing various driving environment information and visualization. As a result of the performance evaluation, the number of executors, the optimal memory capacity, and number of cores for the development server were derived, and the computation performance was superior to that of the other cloud computing.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.3
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• pp.52-60
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• 2018

In the automobile industry, in order to increase the fuel efficiency and conform to the safety regulations, it is necessary to make the vehicles as light as possible. Therefore, it is crucial to manufacture dual phase steels, complex phases steels, MS steels, TRIP steels, and TWIP from high strength steels with a tensile strength of 700Mpa or more. In order to apply ultra-high tensile strength steel to the body, the welding process is essential. Resistance spot welding, which is advantageous in terms of its cost, is used in more than 80% of cases in body welding. It is generally accepted that ultra-high tensile strength steel has poor weldability, because its alloy element content is increased to improve its strength. In the case of the resistance spot welding of ultra-high tensile steel, it has been reported that the proper welding condition area is reduced and interfacial fracture and partial interfacial fracture occur in the weld zone. Therefore, research into the welding quality judgment that can predict the defect and quality in real time is being actively conducted. In this study, the dynamic resistance of the weld was monitored using the secondary circuit process variables detected during resistance spot welding, and the factors necessary for the determination of the welding quality were extracted from the dynamic resistance pattern. The correlations between the extracted factors and the weld quality were analyzed and a regression analysis was carried out using highly correlated pendulums. Based on this research, a regression model that can be applied to the field was proposed.