• 한국구조물진단유지관리공학회 논문집
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• 제19권4호
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• pp.25-34
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• 2015

정밀안전진단시 콘크리트 강도를 추정하기 위한 방법으로 강도추정식을 이용한 방법이 많이 사용되며, 이용되는 추정식은 외국에서 이미 제안된 식이 대부분이고, 적용되는 추정식에 따라서 추정강도의 차이가 심하게 발생하며, 전반적으로 강도추정의 신뢰도가 낮아져 정밀 안전진단 결과의 신뢰성에도 상당한 영향을 미친다. 이런 문제점은 일부 국한된 부분에서 발생하게 되어 다수의 실험을 통하여 신뢰도를 높일 수 있다. 본 논문은 이와 같은 필요성을 포괄하기 위해 실내압축강도와 관련된 신뢰도 평가식을 제안하였다. 확률론적 기법을 이용하여 신뢰도 평가식의 유용성을 검증하였으며 실내압축강도와 추정압축강도의 추이 그래프를 비교하였다. 비교결과, 본 연구에서 제시된 신뢰도 평가식의 유용성을 확인하였다.

• Nuclear Engineering and Technology
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• 제54권2호
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• pp.514-522
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• 2022

Non-destructive testing (NDT) technology is a widely used inspection method for agricultural products. Compared with the conventional inspection method, there is no extensive sample preparation for NDT technology, and the sample is not damaged. In particular, NDT technology is used to inspect the internal structure of agricultural products infested by pests. The introduction and spread of pests during the import and export process can cause significant damage to the agricultural environment. Until now, pest detection in agricultural products and quarantine processes have been challenging because they used external inspection methods. However, NDT technology is advantageous in these inspection situations. In this pilot study, we investigated the feasibility of X-ray computed tomography (X-ray CT) and magnetic resonance imaging (MRI) to identify pest infestation in agricultural products. Three kinds of artificially pest-infested fruits (mango, tangerine, and chestnut) were non-destructively inspected using X-ray CT and MRI. X-ray CT was able to identify all pest infestations in fruits, while MRI could not detect the pest-infested chestnut. In addition, X-ray CT was superior to the quarantine process than MRI based on the contrast-to-noise ratio (CNR), image acquisition time, and cost. Therefore, X-ray CT is more appropriate for the pest quarantine process of fruits than MRI.

• 비파괴검사학회지
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• 제31권2호
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• pp.139-143
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• 2011

충격에 의한 복합재 튜브의 내부 박리 현상은 항공 우주 및 자동차 산업 등에서 흔히 발생되어져 왔다. 이러한 복합재 구조물의 안전성을 평가하기 위해서는 적외선열화상기법(IRT)과 같은 복합재 구조물의 내부 결함을 검출할 수 있는 비파피검사가 필요하다. 적외선 열화상 이미지 패턴 분석에 의해서 내부 결함이 발생한 복합재 튜브의 내 외부 결함 부위를 확인할 수 있다. 본 연구에서는 적외선열화상기법을 이용하여 충격 하중에 따른 복합재 튜브 표면에서 방출하는 적외선 에너지를 감지하여 열 분배로부터 복합재 튜브의 내부 결함을 검출하는 연구를 수행하였다.

• 한국전문물리치료학회지
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• 제24권1호
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• pp.19-29
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• 2017

Background: Patients after rotator cuff (RC) surgery experienced pain, weakness and limited of motion of the shoulder. Physical therapists have used heat therapy, electrotherapy, range of motion (ROM) exercise and other methods to treat patients after RC surgery. In addition, functional taping is also used to support joint movement and to increase shoulder joint stability. Objects: The purpose of this study was to determine the initial effects of functional taping using non-elastic tape on pain, strength and ROM of the shoulder following RC surgery. Methods: Forty-eight patients with who underwent RC surgery volunteered for this study. The subjects were randomly divided into an experimental group (EG, $n_1=25$) and a control group (CG, $n_2=23$). First, non-allergic tape was applied to the shoulder to prevent skin irritation. The EG applied functional taping using non-elastic tape and the CG applied sham taping using elastic tape. Assessment tools included the shoulder pain and disability index for functional activity score, visual analog scale for level of pain, shoulder muscle strength, hand grip strength and ROM testing. Results: Pain score in the both group significantly decreased (p<.05), and change in pain score of in the EG increased significantly than in the CG (p<.05). Shoulder strength and ROM in the both group significantly increased (p<.05). Especially external rotation and extension of the shoulder ROM in the EG increased significantly more than in the CG (p<.05), but the rate of change in the two groups showed no significant difference. Conclusion: These results suggest that functional taping using non-elastic tape was initially effective in decreasing pain score level in patients with RC surgery.

• Asian Pacific Journal of Cancer Prevention
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• 제14권11호
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• pp.6619-6623
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• 2013

Background:The aim of the research was to explore a cost effective, fast, easy to perform, and sensitive method for epidermal growth factor receptor (EGFR) mutation testing. Methods: High resolution melting analysis (HRM) was introduced to evaluate the efficacy of the analysis for dectecting EGFR mutations in exons 18 to 21 using formalin-fixed paraffin-embedded (FFPE) tissues and plasma free DNA from 120 patients. Results: The total EGFR mutation rate was 37.5% (45/120) detected by direct sequencing. There were 48 mutations in 120 FFPE tissues assessed by HRM. For plasma free DNA, the EGFR mutation rate was 25.8% (31/120). The sensitivity of HRM assays in FFPE samples was 100% by HRM. There was a low false-positive mutation rate but a high false-negative rate in plasma free DNA detected by HRM. Conclusions: Our results show that HRM analysis has the advantage of small tumor sample need. HRM applied with plasma free DNA showed a high false-negative rate but a low false-positive rate. Further research into appropriate methods and analysis needs to be performed before HRM for plasma free DNA could be accepted as an option in diagnostic or screening settings.

• Communications for Statistical Applications and Methods
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• 제13권3호
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• pp.503-512
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• 2006

In this paper, the Inverse Weibull distribution parameters have been estimated using a new estimation technique based on the non-parametric kernel density function that introduced as an alternative and reliable technique for estimation in life testing models. This technique will require bootstrapping from a set of sample observations for constructing the density functions of pivotal quantities and thus the confidence intervals for the distribution parameters. The performances of this technique have been studied comparing to the conditional inference on the basis of the mean lengths and the covering percentage of the confidence intervals, via Monte Carlo simulations. The simulation results indicated the robustness of the proposed method that yield reasonably accurate inferences even with fewer bootstrap replications and it is easy to be used than the conditional approach. Finally, a numerical example is given to illustrate the densities and the inferential methods developed in this paper.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1999년도 봄 학술발표회 논문집(I)
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• pp.697-702
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• 1999

Among several non-destructive testing methods, ultrasonic pulse velocity method has been widely used for the evaluation of concrete strength. However, this method might not provide accurate estimated results since factors influencing the relationship between strength and wave velocity is not considered. In this study, the evaluation methods of concrete strength using compression wave velocities measured by either ultrasonic pulse velocity method or impact-resonance method are proposed. A basic equation is obtained by the linear regression with velocity vs. strength data at a specific age and then, ageing factor is employed in the equation to consider the difference of the increasing rate between wave velocity and strength. Strengths predicted by the proposed equation agree well with test results.

• 한국정밀공학회지
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• 제18권5호
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• pp.34-41
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• 2001

More accurate and fast inspection method for mechanical parts and structure is required to guarantee the safety. Conventional methods using compliance method, eddy current method, ultrasonic wave, acoustic emission for non-destructive testing in mechanical parts and structure have been performed as the method of contact with objects to be inspected. With this reason these methods have been taken relatively much time, money, and manpower. In this study, in order to overcome these shortcomings, we used In-plane Electronic Speckle pattern Interferometry(In-plane ESPI) that was full-field measurement and noncontact method. We detected the cracks of the specimen at a real time and measured the length of the crack by using In-place ESPI system. Finally, we compared this results with conventional microscope method.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2009년도 춘계학술대회 논문집
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• pp.984-996
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• 2009

When evaluating the general subgrade states such as geology, stiffness, underground water, compaction and deformation in the Gyeongbu high speed railway, some applicable testing methods should be selected because lots of trains are currently running. The applicable methods includes not only non-destructive tests such as GPR test, electricity resistivity test, MASW proving, but also standard penetration test (SPT), core test, elastic wave tomography through drilling boreholes and measurements using settlement measuring system or inclinometer, etc. In order for evaluating the subgrade states in the Gyeongbu high speed ralway, this study performed GPR test in several sections and drilling boreholes whose locations were chosen after comparing GPR test results and track maintenance history. Furthermore, the progress of subgrade deformations was analysed by comparing previous and this time GPR test results. The results of this study shall be used to understand the general states of currently operating Gyeongbu high speed railway.

• East Asian mathematical journal
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• 제16권2호
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• pp.251-266
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• 2000

The problem of solution uniqueness to the task of determining unknown parameters of mathematical models from input-output observations is studied. This problem is known as structural identifiability problem. We offer a new approach for testing structural identifiability of linear state space models. The approach compares favorably with numerous methods proposed by other authors for two main reasons. First, it is formulated in obvious mathematical form. Secondly, the method does not involve unfeasible symbolic computations and thus allows to test identifiability of large-scale models. In case of non-identifiability, when there is a set of solutions to the task, we offer a method of computing functions of the unknown parameters which can be determined uniquely from input-output observations and later used as new parameters of the model. Such functions are called parametric functions capable of estimation. To develop the method of computation of these functions we use Lie group transformation theory. Illustrative example is given to demonstrate applicability of presented methods.