• IEIE Transactions on Smart Processing and Computing
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• 제3권4호
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• pp.195-204
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• 2014

This paper presents the depth evaluation for object detection by automated assembling robots. Pattern distortion analysis from a structured light system identifies an object with the greatest depth from its background. An automated assembling robot should prior select and pick an object with the greatest depth to reduce the physical harm during the picking action of the robot arm. Object detection is then combined with a depth evaluation to provide contour, showing the edges of an object with the greatest depth. The contour provides shape information to an automated assembling robot, which equips the laser based proxy sensor, for picking up and placing an object in the intended place. The depth evaluation process using structured light for an automated electronics assembling robot is accelerated for an image frame to be used for computation using the simplest experimental set, which consists of a single camera and projector. The experiments for the depth evaluation process required 31 ms to 32 ms, which were optimized for the robot vision system that equips a 30-frames-per-second camera.

• 대한치과교정학회지
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• 제15권1호
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• pp.23-42
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• 1985

The morphology and growth changes of the Craniofacial Complex are important in orthodontics and cephalometrics for analysis and evaluation of facial bone growth are widely used. The author analyzed the data using lateral cephalometric roentgenogram of 75 Korean male and 50 Korean females age of 6 to 10 with normal occlusion to provide informations-relative rates of facial bone growth of Korean which is to be contributed in Korean standard. The results were as follows: 1. Means, standard deviation and coefficient of variation of Korean children were obtained. 2. The item which showed significent difference between male and female was craniofacial height in absolute dimension. 9. No difference of sex was showed in increment of craniofacial height and depth. 4. Among the craniofacial depth increments, the lower facial depth dimension increased most, midfacial depth dimension increased less, and cranial depth dimension increased the least. 5. The horizontal body of mandible showed rapid growing tendency more than did the ascending ramus.

• Structural Engineering and Mechanics
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• 제89권3호
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• pp.301-308
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• 2024

Concrete carbonation is a continuous and slow process from the outside to the inside, in which its penetration slows down with the increased depth of carbonation. In this paper, the results of the evaluation of the measurement of concrete carbonation depth using a non-destructive ultrasonic testing method are presented. According to the results, the relative nonlinear parameter caused more sensitivity in carbonation changes compared to Rayleigh's fuzzy velocity. Thus, the acoustic nonlinear parameter is expected to be applied as a quantitative index to recognize carbonation effects. In this research, combo diagrams were developed based on the results of ultrasonic testing and the experiment to determine carbonation depth using a phenolphthalein solution, which could be considered as instructions in the projects involving non-destructive ultrasonic test methods. The minimum and maximum accuracy of this method were 89% and 97%, respectively, which is a reasonable range for operational projects. From the analysis performed, some useful expressions are found by applying the regression analysis for the nonlinearity index and the carbonation penetration depth values as a guideline.

• Current Optics and Photonics
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• 제8권2호
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• pp.170-182
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• 2024

The dimensional accuracy and consistency of a dual oil circuit centrifugal fuel nozzle are important for fuel distribution and combustion efficiency in an engine combustion chamber. A point cloud measurement method was proposed to solve the geometric accuracy detection problem for the fuel nozzle. An improved variance focus measure operator was used to extract the depth point cloud. Compared with other traditional sharpness evaluation functions, the improved operator can generate the best evaluation curve, and has the least noise and the shortest calculation time. The experimental results of point cloud slicing measurement show that the best window size is 24 × 24 pixels. In the height measurement experiment of the standard sample block, the relative error is 2.32%, and in the fuel nozzle cone angle measurement experiment, the relative error is 2.46%, which can meet the high precision requirements of a dual oil circuit centrifugal fuel nozzle.

• Structural Engineering and Mechanics
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• 제84권6호
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• pp.831-849
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• 2022

One of the most prevalent causes of reinforced concrete (RC) structural deterioration is chloride-induced corrosion. This paper aims to provide a comprehensive insight into the environmental effect of RC's chloride ingress process. The first step is to investigate how relative humidity, temperature, and wind influence chloride ingress into concrete. The probability of initiation time of chloride-induced corrosion is predicted using a probabilistic model that considers these aspects. Parametric analysis is conducted on several factors impacting the corrosion process, including the depth of concrete cover, surface chloride concentration, relative humidity, and temperature to expose environmental features. According to the findings, environmental factors such as surface chloride concentration, relative humidity and temperature substantially impact on the time to corrosion initiation. The long- and short-distance impacts are also examined. The meteorological data from the National Meteorological Center of China are collected and used to analyze the environmental characteristics of the chloride ingress issue for structures along China's coastline. Finally, various recommendations are made for improving durability design against chloride attacks.

• 한국농촌건축학회논문집
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• 제25권4호
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• pp.37-44
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• 2023

As a basic study to analyze the relative importance of external space in urban development projects, this study selects evaluation indicators for external space planning and then analyzes systematic external space planning through expert surveys. The scope of the study is to examine the criteria of evaluation items for external space derived from existing studies and to suggest the importance and priority of evaluation items. As a research method, we reviewed the legal and research literature on landscape planning and external space-related guidelines, and conducted a primary review of external space planning evaluation items analyzed by questionnaire. The reviewed items were again reviewed and selected through expert group discussions (FGI). The selected evaluation items were surveyed by expert groups and analyzed in depth using the hierarchical analysis method (AHP). Looking at the relative importance of the calculated sub-items, among the 17 sub-items, 'planning open space' (.096) is the largest, followed by 'pedestrianization' (.082), 'linking with adjacent buildings, streets, parks, and green areas' (.077), 'securing public space through various planning techniques such as linking with pedestrian paths' (.066), 'Plan the placement, form, and scale of buildings in consideration of the identity of the destination' (.065), 'Plan buildings, streets, parks, and green spaces in an integrated and holistic manner' (.065), 'Harmonize with the surrounding environment (landscape)' (.063), 'Harmonize with surrounding buildings and apply landscape planning in urban planning' (.063), 'Entrances and lower floors of buildings are planned as parks for users and pedestrians' (.060), 'Preserve and expand green areas and establish maintenance plans for urban greening' (.054), 'Form the basis for a comfortable life for urban residents by providing long-term development directions' (.047), 'Activate community activities and plan pedestrian environments and streetscapes considering human scale' (.047), 'Establish and propose basic directions for urban greening' (.046), 'Plan buildings, streets, parks, and green areas considering the hierarchy and characteristics of the landscape structure' (.045), 'Plan for integrated land use' (.045), 'Create green axes in connection without cutting them due to development activities' (.044), and 'Apply barrier free design' (.034).

• 대한토목학회논문집
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• 제7권3호
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• pp.175-181
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• 1987

개단 강관말뚝의 선단지지력은 폐색 효과에 의하여 발생되는데 이 폐색 효과는 말뚝의 직경에 대한 관입깊이의 비 즉, 상대 관입깊이와 밀접한 관계가 있는 것으로 알려져 있다. 이에 본 연구에서는 폐색 효과를 종합적으로 평가하기 위하여 지반의 상대밀도와 모형말뚝의 상대 관입 깊이를 달리하여 재하시험을 수행하였으며 개단 말뚝의 유효직경을 축소시킬 목적으로 십자 모양의 칸막이 판을 선단에 부착한 모형말뚝에 대한 시험도 병행하였다. 그 결과로서 개단 말뚝은 말뚝의 극한 지지력을 기준으로 폐색효과를 평가할 때 말뚝 타설 지반이 단단할수록 작은 상대관입깊이에서 큰 폐색효과를 얻을 수 있으나 100%의 폐색효과는 지반의 상대밀도에 상관없이 대략 상대관입깊이 25 정도에서 발휘된다는 사실을 알았다. 그리고 칸막이 판의 설치로 인한 폐색효과의 증대는 기대하기 어려운 것으로 판단된다.

• Geomechanics and Engineering
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• 제38권2호
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• pp.165-177
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• 2024

Liquefaction phenomenon refers to a phenomenon in which excess pore water pressure occurs when a dynamic load such as an earthquake is rapidly applied to a loose sandy soil ground where the ground is saturated, and the ground loses effective stress and becomes liquid. The laboratory repetition test for liquefaction evaluation can be performed through a repeated triaxial compression test and a repeated shear test. In this regard, this study attempted to evaluate the effects of the relative density of sand on the liquefaction resistance strength according to particle size distribution using repeated triaxial compression tests, and additional experimental verification using numerical analysis was conducted to overcome the limitations of experimental equipment. As a result of the experiment, it was confirmed that the liquefaction resistance strength increased as the relative density increased regardless of the classification of soil, and the liquefaction resistance strength of the SP sample close to SW was quite high. As a result of numerical analysis, it was confirmed that the liquefaction resistance strength increased as the confining pressure increased under the same relative density, and the liquefaction resistance strength did not decrease below a certain limit even though the confining pressure was significantly reduced at a relatively low relative density. This is judged to be due to a change in confining pressure according to the depth of the ground. As a result of analyzing the liquefaction resistance strength according to the frequency range, it was confirmed that there was no significant difference from the laboratory experiment results in the basic range of 0.1 to 1.0 Hz.

• 비파괴검사학회지
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• 제26권4호
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• pp.231-238
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• 2006

위상 배열 초음파 기법을 이용한 국내 표준형 윈전 저압 터빈의 디스크 검사에 대하여 연구하였다. 이를 위하여 디스크 mockup을 제작하고 결함을 가공하였으며 결함에 대한 검출과 길이 측정 방법에 따른 결과를 고찰하였다. 깊이 측정에서 릴은 결함은 AATT(absolute arrival time technique)방법 혹은 RATT (relative arrival time technique)방법을 사용하여 깊이를 측정할 수 있었으나, 조기에 발견하여야 할 깊이가 깊지 않은 결함은 이와 같은 방법으로 깊이를 측정할 수 없었다. 이 경우 결함 신호가 나타나는 각도 범위를 이용하여 결함 깊이를 측정하였으며 유용한 도구임을 확인하였다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2000년도 봄 학술발표회 논문집
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• pp.688-693
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• 2000

Recently great efforts and investment have been made in order to evaluate concrete durability by steel corrosion. But most of study is relatively or qualitatively estimated, therefore it has a great limitation in evaluating a remaining service life of concrete. In this research, steel corrosion rate was measured quantitatively by polarization resistance method and multi-regressed considering chloride, carbonation, coverage depth, relative humidity, W/C, and the use of deicing salts. And a half cell potential method was used at th same time for the purpose of comparing with polarization resistance method.