• 한국측량학회:학술대회논문집
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• 한국측량학회 2007년도 춘계학술발표회 논문집
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• pp.243-248
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• 2007

This study proposed a procedure to improve the error defection of attached cadastral maps using digital map data. In addition, this study also provided the direction for the accuracy improvement of attached cadastral maps by comparing analysis methods. - such as centroid, Lee Sallee shape index, and area index. The analysis is performed as follows. First, by using centroid measurement, the center point of cadastral maps and attached cadastral maps are compared. Secondly by using Lee Sallee shape measurement, the location accuracy of range area is investigated. Thirdly, by using area measurement, the range area within allowable error scope is verified. Based on analysis, the discrepancy between cadastral maps and the attacked cadastral maps are detected as follows; 98.2% from Lee Sallee shape index, 41.8% from centroid, 15.4% from area index in the whole error.

• International Journal of Safety
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• 제6권2호
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• pp.1-7
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• 2007

In this study mechanical strength of A53B carbon steel was analyzed using several types of test specimens directly machined from oil recycling pipe experienced a failure due to hydrogen attack in chemical plants. High temperature hydrogen attack (HTHA) is the damage process of grain boundary facets due to a chemical reaction of carbides with hydrogen, thus forming cavities with high pressure methane gas. Driven by the methane gas pressure, the cavities grow on grain boundaries forming intergranular micro cracks. Microscopic optical examination, tensile test, Charpy impact test, hardness measurement, and small punch (SP) test were performed. Carbon content of the hydrogen attacked specimens was dramatically reduced compared with that of standard specification of A53B. Traces of decarburization and micro-cracks were observed by optical and scanning electron microscopy. Charpy impact energy in hydrogen attacked part of the pipe exhibited very low values due to the decarburization and micro fissure formation by HTHA, on the other hand, data tested from the sound part of the pipe showed high and scattered impact energy. Maximum reaction forces and ductility in SP test were decreased at hydrogen attacked part of the pipe compared with sound part of the pipe. Finite element analyses for SP test were performed to estimate tensile properties for untested part of the pipe in tensile test. And fracture toughness was calculated using an equivalent strain concept with SP test and finite element analysis results.

• 한국유체기계학회 논문집
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• 제12권4호
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• pp.54-62
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• 2009

The feedwater heaters are Critical components in a nuclear power plant. As the operation years of heaters go by, the maintenance costs required for continuous operation increase. When the carbon steel components in nuclear make contact with running fluid, the wall thinning caused by FAC (flow accelerated corrosion) can be generated. Local wall thinning is inevitable at the area around wet steam entrance to be attacked due to the long term operation. Sometimes the shell with thinned wall is eventually ruptured. To identify the relationship between the local wall thinning and fluid behavior of the feedwater heater, the practical data of a plant, which were based on ultrasonic thickness measurement tests, were analyzed and CFD(Computed Fluid Dynamics) analyses were performed.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권9호
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• pp.4418-4437
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• 2017

In this paper a three-phase secure compressive sensing (CS) and received signal strength (RSS) based target localization approach is proposed to mitigate the effect of malicious node attack. RSS measurements are first arranged into a group of subsets where the same measurement can be included in multiple subsets. Intermediate target position estimates are then produced using individual subsets of RSS measurements and the CS technique. From the intermediate position estimates, the residual error vector and residual error square vector are formed. The least median of residual error square is utilized to define a verifier parameter. The selected residual error vector is utilized along with a threshold to determine whether a node or measurement is under attack. The final target positions are estimated by using only the attack-free measurements and the CS technique. Further, theoretical analysis is performed for parameter selection and computational complexity evaluation. Extensive simulation studies are carried out to demonstrate the advantage of the proposed CS-based secure localization approach over the existing algorithms.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 추계 학술발표회 논문집
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• pp.761-764
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• 2006

Nowadays, It is openly reported that concrete structures have been attacted by freez and thaw. However, it is not clearly defined how to understand & measure the test method of freez and thaw of concrete structures. Thus, in this strudy, We performed the research with the test results using provision of ASTM C672 of freez and thaw durability of concrete. Also, it is identified suitable test method to measure of freez and thaw.

• 가정과삶의질연구
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• 제20권3호
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• pp.27-37
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• 2002

The Pattern of Young Child-Mother Attachment and the Self-Concept in Young Children. This work sheds light on the patterns of chi1dren's attachment to their mother and the self-concept of young children. Ninety-two participants were selected from kindergarten and nurseries in the city of Taegu. All the children were from 3 to 5 clears old. The measurement instruments were the attachment story completion task, created by Cassidy, and the self-concept test, designed and used by Bently and Yeatts. The data was analyzed by using frequencies, percentages, independent-samples t-test, one-way ANOVA, and the Scheffe test. The study's major findings are as follows: First, in the area of young child-mother attachments, the most common pattern was a secure attachment. The percentage of insecure-avoidant attachment was similar to that of the insecure-ambivalent attachment. Second, in terms of gender, there were no significant differences in self-concept among young children. Third, the self-concept held by young children varied significantly according to age. The younger the age, the more positive was the self-concept. Finally, the self-concept of children varied greatly according to the pattern of child-mother attachment. Those children who were more securely attacked to their mothers evidenced a more positive self-concept than those children who were insecurely attached to their mother.

• 한국전기전자재료학회논문지
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• 제27권4호
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• pp.221-225
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• 2014

In modern times, threat of high power electromagnetic wave is increasing. When the electrical grid and communication network are attacked by these high power electromagnetic wave, the whole infrastructure is paralyzed. To protect the infrastructure from these high power electromagnetic wave threat, the shielding facility that can block high power electromagnetic wave is constructed. Also shielding effectiveness evaluation about the constructed facility is important. But, because of space efficiency and saving of construction cost to construct the actual shielding facility, the shielding room wall is generally adjacent to exterior concrete structures. As space between shielding facility wall and concrete structures is very small, arranging the transmitting antenna exterior shielding facility is realistically difficult. Therefore, in this research, The shielding effectiveness measurement plan in the state of exterior narrow space of HEMP shielding facility is presented. And to apply this plan, The influence of shielding effectiveness according to the size of the shielding facility is analyzed.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2008년도 International Symposium on Remote Sensing
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• pp.49-52
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• 2008

New Orleans located in the estuary of the Mississippi River was attacked by Hurricane Katrina and suffered big flood on August 2005. Since unconsolidated Holocene to middle Miocene strata is the main basement rocks, land subsidence has been occurred steadily due to soil compaction and normal faulting. It was reported that the maximum subsidence rate from 2002 to 2005 was -29 mm/yr. Many studies in the area have been carried out for understanding the subsiding and potential risks caused by ground subsidence are weighted by the fact that a large area of the city is located below the mean sea level. A small baseline subset (SBAS) method is applied for effectively measuring time-series LOS (Line-of sight) surface deformation from differential synthetic aperture radar interferograms in this study. The time-series surface deformation at New Orleans was measured from RADARSAT-1 SAR images. The used dataset consists of twenty-one RADARSAT-1 fine beam mode images on descending orbits from February 2005 to February 2007 and another twenty-one RADARSAT-1 standard beam mode images on ascending orbits from January 2005 to February 2007. From this dataset, 25 and 38 differential interferograms on descending and ascending orbits were constructed, respectively. The vertical and horizontal components of surface deformation were extracted from ascending and descending LOS surface deformations. The result from vertical component of surface deformation indicates that subsidence is not significant with a mean rate of -3.1${\pm}$3.2 mm/yr.

• KSBB Journal
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• 제11권1호
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• pp.86-91
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• 1996

전분이 충전된 폴리에틸렌 필름의 생분해도를 측정하기 위해, ${\alpha}$-amylase가 효과적으로 전분을 분해 시킬 수 있는 반응조건을 설정하고 설정된 반응조건 에서 반응시킨 후 산물인 당을 측정하여 분해정도를 결정하였다. 효과적 인 반응온도는 $80^{\circ}C$이고, pH는 6.3-7.3 사이가 적당하였다. 효소반응에 적당한 r amylase량은 1 mg 전분당 100unit이 었다. 이와 같 은 반응조건하에서, 전분의 무게함유량이 각각 5%. 10%, 15%. 20% 인 폴리에틸렌 필름을 ${\alpha}$-amylase 와 반응시킨 결과 전분이 함유된 비율과 생성된 환 원당간에 대융의 관계를 보였다. 따라서 필름 내에 함유된 생분해가 가능한 전분량을 정량화하는데 calibration 역할을 할 것으로 기대된다. 이 때 분해되 어진 전분의 양은 충전된 전체 전분량의 약 40%에 해당하는 값으로 나타났으며, 나머지는 필름 내부에 분산되 어 있어 ${\alpha}$-amylase의 공격을 받지 못하기 때 문으로 생각된다. 본 실험을 통해 최적화된 반응조 건하에셔 분해시킴으로써, 계면활성제를 첨가하여 분해도를 높인 기존의 데이타보다 더 높은 분해도를 얻을 수 있었다.

• Smart Structures and Systems
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• 제26권3호
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• pp.291-309
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• 2020

To study oceanic and meteorological problems related to climate change, Korea has been operating several ocean research stations (ORSs). In 2011, the Gageocho ORS was attacked by Typhoon Muifa, and its structural members and several observation devices were severely damaged. After this event, the Gageocho ORS was rehabilitated with 5 m height to account for 100-yr extreme wave height, and the vibration measurement system was equipped to monitor the structural vibrational characteristics including natural frequencies and modal damping ratios. In this study, a mass reallocation method is presented for structural model updating of the Gageocho ORS based on the experimentally identified natural frequencies. A preliminary finite element (FE) model was constructed based on design drawings, and several of the candidate baseline FE models were manually built, taking into account the different structural conditions such as corroded thickness. Among these candidate baseline FE models, the most reasonable baseline FE model was selected by comparing the differences between the identified and calculated natural frequencies; the most suitable baseline FE model was updated based on the identified modal properties, and by using the pattern search method, which is one of direct search optimization methods. The mass reallocation method is newly proposed as a means to determine the equivalent mass quantities along the height and in a floor. It was found that the natural frequencies calculated based on the updated FE model was very close to the identified natural frequencies. In conclusion, it is expected that these results, which were obtained by updating a baseline FE model, can be useful for establishing the reference database for jacket-type offshore structures, and assessing the structural integrity of the Gageocho ORS.