• Smart Structures and Systems
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• v.13 no.5
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• pp.775-796
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• 2014

This study presents a vibration-based health monitoring strategy for short span bridges utilizing an inspection vehicle. How to screen the health condition of short span bridges in terms of a drive-by bridge inspection is described. Feasibility of the drive-by bridge inspection is investigated through a scaled laboratory moving vehicle experiment. The feasibility of using an instrumented vehicle to detect the natural frequency and changes in structural damping of a model bridge was observed. Observations also demonstrated the possibility of diagnosis of bridges by comparing patterns of identified bridge dynamic parameters through periodical monitoring. It was confirmed that the moving vehicle method identifies the damage location and severity well.

• Journal of Institute of Control, Robotics and Systems
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• v.9 no.8
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• pp.640-646
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• 2003

We presents an edge-based point correlation algorithm for fast and stable visual inspection system. Conventional algorithms based on NGC(normalized gray-level correlation) have to overcome some difficulties in applying automated inspection systems to real factory environment. First of all, NGC algorithms involve highly complex computation and thus require high performance hardware for realtime process. In addition, lighting condition in realistic factory environments is not stable and therefore intensity variation from uncontrolled lights gives many troubles for applying NGC directly as pattern matching algorithm. We propose an algorithm to solve these problems, using thinned and binarized edge data, which are obtained from the original image. A point correlation algorithm with the thinned edges is introduced with image pyramid technique to reduce the computational complexity. Matching edges instead of using original gray-level image pixels overcomes problems in NGC method and pyramid of edges also provides fast and stable processing. All proposed methods are proved by the experiments using real images.

• Journal of Korean Society for Quality Management
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• v.24 no.2
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• pp.25-43
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• 1996

This paper presents the optimal and practical constant-stress accelerated life test plans for the lognormal lifetime distribution tinder assumptions of intermittent inspection and Type-I censoring. In an optimal plan, the low stress level and the proportions of test units allocated at each stress are determined under given inspection scheme and number of inspections such that the asymptotic variance of the maximum likelihood estimator of a certain quantile at use condition is minimized. Although the practical plan adopts the same design criterion, it involves three rather than two overstress levels in order to compromise the practical deficiencies of the optimal plan. Computational experiments are conducted to choose an allocation plan and a inspection scheme of the practical plan and to compare with test plans over a range of parameter values.

• Journal of the Korea Safety Management & Science
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• v.12 no.4
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• pp.73-80
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• 2010

The purpose of this study was to investigate the actual conditions of radiation safety supervision in animal clinics using inspection standard of X-ray generator for diagnosis. The surveys for inspection standard system, equipment condition, and safety supervision were carried out in 18 animal clinics randomly. The inspection standard included reproducibility of dose exposure, kVp, mAs, collimator accuracy test, collimator luminance test, X-ray view box luminance test, grounding system equipment test and external leakage current test. The surveys of equipment condition and safety supervision used one-on-one interview with 5 points measurement. As a result, 44.44% of reproducibility of dose exposure was proper, 81.25% of kVp test was good, and 100% of mAs test was appropriate. Also, 66.66% of collimator accuracy test was proper, 61.11% of collimator luminance test was good, 53.13% of X-ray view box luminance test was suitable. In addition, only 5.55% of grounding system equipment and ground resistance was proper, 63.64% of external leakage current test was appropriate in grounding system equipment test. The 100mA electric capacity of X-ray generator for diagnosis was popular with 44.44%, and its 55.56% was purchased used equipment. Monthly average of less than 50 times (61.11%) was top frequency in use, and no animal clinic had a thermo-luminescence dosimeter(TLD). The 16 animal clinics with radiation safety zone and 2 without radiation safety zone were appeared.

• Fire Science and Engineering
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• v.23 no.4
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• pp.137-144
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• 2009

This paper was studied on the problem of field inspection tester of the photoelectric type smoke detector. The experiment objects were chosen 3 type's testers such as A type (incense), B type (dimethylpolysiloxane), C type (mixtures of hydrocarbon) which were used for performance checking of the photoelectric type smoke detector for the fire protection. The experimental methods were used reliability verification experiment, performance verification experiment and performance change of fire detector by smoke component. It was confirmed through the experiment that the testers had problems of smoke concentration condition and wind velocity condition and smoke component. Consequently, this paper verified that the field inspection testers of the photoelectric type smoke detector had problems in the inspection of fire protection.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.569-572
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• 2008

A series of the field inspection and the test have been performed on 297 existing bridges, in order to evaluate the bridges since 1995. In this study, based on the test results of the in-depth inspection, the identification of the extent of the chloride content and the incidence of the carbonation depth was conducted, and construction age and member type, environment condition were considered in this analysis. According to simple regression of the tested carbonation depth, the carbonation rate coefficient of the bridges in metropolises was estimated 5.41 and greater than 3.89 and 1.91 in case of marine condition and etc respectively. After measuring chloride content in concrete member, it was concluded that the chloride content of the bridges in marine condition was 4.7 times greater than the others. Especially, slabs had the most highly chloride content and it was estimated 0.709 $kg/m^3$

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.1752-1759
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• 2007

In the new Seoul-Busan high speed railroad construction specially city center passage roadbed establishment is recommended the staibility for the existing subway tunnel segments of Busan subway line No. 1 and No.2. regarding the appearance condition, a quality condition and the durability of the objective facility site exact inspection, and it evaluates the numerical analysis which uses MIDAS GTS it leads and there is the objective of the place where the stability of the objective facility and this tunnel it investigates. To immediacy of the on-the-spot inspection result whole facility it is a condition where the reinforcement which is simple not to be hindrance is necessary, 2nd Line case it is a condition which transfer is good but the general defect and the damage which occur from the tunnel of NATM type were confirmed part. While roadbed establishment constructing that the continuous maintenance is necessary, it is judged. The result of 1st, 2nd Line maximum sinkage, unequal sinkage and the lining stress of numerical analysis are within permission and the damage degree is appearing with the fact that the degree it will can disregard it is slight. But it enforces necessary Pre-grouting in order to minimize an actual tunnel face conduct and when the tunnel is excavated it is judged with the fact that necessary to minimize the outflow possibility.

• Journal of the Korea institute for structural maintenance and inspection
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• v.21 no.1
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• pp.15-22
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• 2017

This study focuses on the investigation of bond strength of magnesium potassium phosphate cement mortar(MKPC) according to moisture condition of substrate. Tensile bond test, shear bond test and interfacial bond test are adopted for evaluating the adhesion characteristics of MKPC to conventional cement mortar substrate. The main experimental variables are test methods and moisture levels of substrate. Because the moisture condition of the substrate may be critical to achieving bond, optimum moisture condition for a conventional concrete substrate has evaluated in this study. The results are as follows ; The effects of moisture condition at substrate into the bonding of MKPC are less different than polymer cement mortar and epoxy mortar. But the saturated and surface dry condition is the most appropriate moisture level among the considered, followed by saturated condition and wet condition. Thus, an adequate moisture level of substrate for MKPC is essential for good bond strength.

• Proceedings of the Korean Geotechical Society Conference
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• 2002.10a
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• pp.188-200
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• 2002

In this study, a pavement evaluation method is introduced by a case study of the measurement data obtained in Incheon International Airport. Based on the results obtained by both visual inspection and automobile inspection equipments, the pavement surface condition is evaluated and used for maintenance and rehabilitation strategy for pavement. In addition, the special attention was given to the back calculation and solution technique of E-modulus by FWD's deflection data in Pavement.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2000.10a
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• pp.590-594
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• 2000

One of the most important factors for a leather quality inspection is its surface condition. So far a leather quality level has been discriminated by human's eye inspection, But, these kinds of method needs a lot of labor time and cause decision mistakes from an optical illusion. It means leather quality inspection is very subjective and there is no consistency. In this study, we present computer vision based a leather quality inspection system using an Artificial intelligence. Suggested system ran give standard spec for a leather quality and take human inspection duty place.