• Journal of Korean Tunnelling and Underground Space Association
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• v.8 no.4
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• pp.377-388
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• 2006

Most structures experience deterioration after construction. A routine inspection and maintenance must be accomplished for the efficient use of the structures. The routine inspection will play a major role on the determination of maintenance period and method. This study aims development of an automated tunnel inspection system based upon a 3 dimensional laser scanner. As for the initial stage of the project, a prototype tunnel scanner has been developed. The development of a tunnel scanner prototype follows comparison between image scanning and laser scanning system and investigation on the applicability and adaptivity of the scanners to the railway tunnel scanner. The applicability of the laser scanner on the railway tunnel has been confirmed from the pilot test by using commercialized general purpose close range laser scanner and applicability of a laser scanner as a railway tunnel scanner has been checked. From the result, a prototype of railway tunnel scanner has been built and the calibration of the system was carried out. Finally the developed tunnel laser scanner has been applied to different shapes and sizes of tunnels in use.

• Journal of IKEEE
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• v.10 no.1 s.18
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• pp.40-48
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• 2006

This paper presents a new rooftop surface estimation method from 3D line segments. 3D rooftop surface estimation is based on the hierarchical grouping and initiated by 3D line merging for the disconnected 3D line segments. Merged 3D lines are applied to the detection of rooftop by surface estimating technique. To estimate surfaces we detect L-corner and T-corner points, and find fixed reliable junction points. The hypothesis of the possible rooftop surfaces are estimated as polygonal surfaces by these fixed junction points and building's rooftop models are generated by testing the possible surfaces in terms of assumptions of building surface properties. We carried out experiments by synthetic images on Avenches data set and the experimental results showed that we could reliably build 3D model with 3D surfaces, errors of which came up with 0.4 - 1.3 meter, 2.5 times more accurate than the elevation date from the conventional area-based stereo.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.19 no.4
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• pp.13-29
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• 2020

Automobiles have long been an essential part of daily life, but the social costs of car traffic accidents exceed 9% of the national budget of Korea. Hence, it is necessary to establish prevention and response system for car traffic accidents. In order to present a model that can classify and predict the degree of injury in car traffic accidents, we used big data analysis techniques of K-nearest neighbor, logistic regression analysis, naive bayes classifier, decision tree, and ensemble algorithm. The performances of the models were analyzed by using the data on the nationwide traffic accidents over the past three years. In particular, considering the difference in the number of data among the respective injury severity levels, we used down-sampling methods for the group with a large number of samples to enhance the accuracy of the classification of the models and then verified the statistical significance of the models using ANOVA.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.40 no.6
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• pp.98-105
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• 2003

We propose a new technique of deinterleaving multiple radar pulse sequences by means of genetic algorithm for threat identification in electronic warfare(EW) system. The conventional approaches based on histogram or continuous wavelet transform are so deterministic that they are subject to failing in detection of individual signal characteristics under real EW signal environment that suffers frequent signal missing, noise, and counter-EW signal. The proposed algorithm utilizes the probabilistic optimization procedure of genetic algorithm. This method, a time-of-arrival(TOA) only strategy, constructs an initial chromosome set using the difference of TOA. To evaluate the fitness of each gene, the defined pulse phase is considered. Since it is rare to meet with a single radar at a moment in EW field of combat, multiple solutions are to be derived in the final stage. Therefore it is designed to terminate genetic process at the prematured generation followed by a chromosome grouping. Experimental results for simulated and real radar signals show the improved performance in estimating both the number of radar and the pulse repetition interval.

• Journal of Energy Engineering
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• v.23 no.4
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• pp.263-271
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• 2014

Corrective thermal performance analysis is required for thermal power plants to determine performance status of turbine cycle. We developed classification method for main feed water flow to make precise correction for performance analysis based on ASME (American Society of Mechanical Engineers) PTC (Performance Test Code). The classification is based on feature identification of status of main water flow. Also we developed predictive algorithms for corrected main feed-water through Support Vector Machine (SVM) Model for each classified feature area. The results was compared to estimations using Neural Network(NN) and Kernel Regression(KR). The feature classification and predictive model of main feed-water flow provides more practical methods for corrective thermal performance analysis of turbine cycle.

• Journal of Korean Society of Steel Construction
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• v.18 no.6
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• pp.677-686
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• 2006

In this paper, a more practical and realistic method is proposed to establish the lifetime optimum maintenance strategies of the deteriorating bridges considering the life-cycle performance as well as life-cycle cost. The genetic algorithm is applied to generate the set of maintenance scenarios that is the multi-objective combinatorial optimization problem related to lifetime performance and cost as separate objective functions, and the technique to select optimum tradeoff maintenance scenario is presented. Optimum maintenance scenarios could be generated not only at the individual member level but also at the system level of the bridge. Through the analytical results of applying the proposed methodology to the existing bridge, it is expected that the methodology will be effectively used to determine the optimum maintenance strategy for introducing a real preventive maintenance system and overcoming the limits of existing maintenance methods.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.46 no.7
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• pp.47-52
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• 2009

H.264 video coding standard is widely used due to the high compression rate and quality. The motion compensation is the most time-consuming and complex unit in the H.264 decoder. The performance of the motion compensation is determined by the calculation of pixel interpolation and management of the reference pixels. The reference pixels read from external memory using efficient memory management for data reuse is necessary along with the high performance interpolators. We propose the architecture of a motion compensation unit for H.264 decoders. It is composed of 2-dimensional circular register files, a motion vector predictor and high performance interpolators with low complexity. The 2-dimensional circular register files reuse reference pixel data as much as possible, and feed reference pixel data to interpolators without any latency and complex logic circuits. We design a motion compensation unit and a intra-prediction unit and integrate them into a prediction unit and verify the operation and the performance.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.45 no.3
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• pp.42-50
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• 2008

We developed a visual inspection system for detecting defective products. Most existing inspection systems are designed to be dedicated to one product, which makes operator spend extra money and time to adopt other products. In this work, we propose a flexible visual inspection system that can inspect various products without any additional major job at a low-cost. The developed system contained image processing algorithm libraries and user-friendly graphic interface for adaptable image-based inspection system. We can find a proper threshold value using the proposed algorithm which uses correlation coefficient between a non-defective product and existing sample images of defective product. And We tested the performance of the proposed algorithm using Otsu's method. The proposed system is applied to a automated inspection line for cellular phone.

• 한국HCI학회:학술대회논문집
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• 2006.02b
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• pp.795-802
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• 2006

현대의 소비자는 더 이상 단순히 감성적 소구에 의해서나 기술적 기능을 제공하는 것으로 제품을 구매하지 않는다. 제품의 결정은 사용자와 제품 간의 상호작용에 따른 정서, 인지, 행위 등에 의한 총체적인 경험에 의한 것이며, 그러한 소비자들의 경험은 지리적, 역사적 전통으로 고착된 문화적 특성이 제품을 통한 사용자 경험의 기저에서 작용함으로써 문화권 별, 국가 별로 각기 다르게 구성된다. 특별히 음식 문화는 어느 나라이든 자연 조건의 영향과 함께 오랜 역사 속에서 형성되었기 때문에 독특하고 다양한 문화적 차이를 지니고 있으며 이러한 문화적 차이는 냉장고 사용에 있어서 다양한 사용행태를 구분 짓는다. 따라서 본 연구를 통해 식품 종류에 의한 영향뿐 아니라 내부 공간 활용의 패턴, 냉장고 환경 설정에 대한 능동적인 태도, 냉장고에서 제공하는 파티션이나 옵션에 대한 수용 정도, 식품의 정리 원칙에 대한 준수 정도 등에 따른 사용행태 간의 차이점을 발견하고, 차별적 사용행태의 기저에 존재하는 문화적 요인을 분석하여 문화적 차이가 사용자의 경험에 영향을 끼치게 됨으로 인하여 냉장고 디자인에 어떠한 변화를 초래하는지 그 연관성을 밝혀내고자 한다. 보다 실제적인 용도로 활용 가능하도록 냉장고 제작의 상업적인 측면을 고려하여 냉장고 내상의 레이아웃에 중점을 두어 본 연구를 진행하였다. 본 연구는 설문과 현장 관찰을 통해 정량적 관찰을 중심으로 분석하였다. 두 국가의 문화 비교를 위한 설문은 이미 여러 연구자료에 의해 검증된 Trompenaars의 문화 변수를 바탕으로 제작 하였다. 또한 정량적 연구에서 발견될 수 없는 문화권 별 여러 특징들에 대한 데이터를 구체적으로 수집하기 위하여 정성적인 연구 방식의 일환으로 실제 관찰 및 사용자 인터뷰를 실시하였으며, 이를 통하여 현상의 원인 및 사용자의 의도를 파악하도록 연구를 진행하였다.

• Journal of the Korean Geotechnical Society
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• v.29 no.3
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• pp.5-13
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• 2013

The compression index, representing the compressibility of clay, is generally obtained from the consolidation test, or predicted by empirical correlations using soil properties. However, empirical methods have regional limitations, because the compression index is affected not only by soil properties but also by site characteristics, such as deposition conditions and stress history. In this study, a method evaluating the compression index from typical soil properties is suggested using the characteristics of reconstituted clay. By analyzing the consolidation test results of Busan clay, the suggested method is verified, and the analysis of prediction error is carried out. It is shown that the proposed method evaluates the compression index more accurately than empirical methods previously suggested. The prediction errors occur by assumption, and are inversely proportional to $e_{cross}/e_0$, obviously.