• Smart Structures and Systems
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• 제33권2호
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• pp.105-118
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• 2024

In order to realize tiny bridge crack discovery by UAV-based machine vision, a novel method combining deep learning and tensor voting is proposed. Firstly, the grid images of crack are detected and descripted based on SE-ResNet50 to generate feature points. Then, the probability significance map of crack image is calculated by tensor voting with feature points, which can define the direction and region of crack. Further, the crack detection anchor box is formed by non-maximum suppression from the probability significance map, which can improve the robustness of tiny crack detection. Finally, a case study is carried out to demonstrate the effectiveness of the proposed method in the Xiangjiang-River bridge inspection. Compared with the original tensor voting algorithm, the proposed method has higher accuracy in the situation of only 1-2 pixels width crack and the existence of edge blur, crack discontinuity, which is suitable for UAV-based bridge crack discovery.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2001년도 가을 학술발표회 논문집
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• pp.1185-1192
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• 2001

This paper reviews available techniques for monitoring corrosion of steel in concrete. The need for early detection and diagnosis of corrosion related deterioration in reinforced structures is widely acknowledged. This is particularly important in reinforced concrete structures on account of the economic and social significance of the problem. The current generally used on-site procedure for corrosion monitoring of reinforced structures employs a method of half-cell surface potential measurements. While the technique has provided a useful means of delineating areas of high or low corrosion risk, there are difficulties in its use and interpretation when assessing rates of deterioration. Electrochemical techniques are by far the most suitable for corrosion monitoring purpose and meet most of the requirements. The aim of this paper is to describe the electric resistance sensor(ER sensor) and electrochemical techniques employed to monitor and estimate corrosion rates of reinforcement. Early detection and diagnosis of corrosion hazards allows preventive measures to be taken, hence the typically expensive repair of severely deteriorated structures can be avoided.

• 대한임상검사과학회지
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• 제39권3호
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• pp.161-166
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• 2007

To develop a rapid and reliable single-tube-based PCR technique for detection simultaneously the quinolone resistance qnrA, qnrB and qnrS genes. After multiple alignment, primers were designed to detect known qnr variants. I was used for A total of 43 extented-spectrum ${\beta}$-lactamases (ESBLs) producing Escherichia coli and Klebsiella pneumoniae isolated from university hospital were tested for screening, as with qnr genes. In optimized conditions, all positive controls confirmed the specificity of the PCR primers. Out of 43 isolates, qnrA genes were detected 19 (44.2%), qnrB genes 5 (11.7%), qnrS genes 15 (34.9%) and 8 (18.6%) isolates were not detected. I report here a fast and reliable technique for rapid screening of qnr positive strains to be used for epidemiological surveys.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2004년도 춘계학술발표대회 논문집
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• pp.119-122
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• 2004

A CPGFRP(Carbon Powder Glass Fiber Reinforced Plastics) sensor was fabricated for fine crack detection of structures. The electrical resistance of the sensor was measured on condition of various composition of carbon powders and thickness of bundle of glass fibers. The resistance was decreased as the increase of the content of carbon powders and the TEX of the glass fibers. In the case of loading on CPGFRP sensor, because inner crack was propagated, the part of percolation structures was disconnected. The sensor is superior to carbon fiber for the detecting ability of fine crack.

• 대한전자공학회논문지
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• 제12권3호
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• pp.26-29
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• 1975

본 논문은 먼저 n상다이오드평균검파전로와 n상다이오드 포낙선검파국락의 정기파 신호에 대한 입력등가저항을 검파각로의 부하단에서 발생하는 전력손실로 부터 해석적으로 구하였다. 또한 동일한 방법으로 임의의 주기적 신호에 대한 n상다이오드 포낙선검액회로의 입력권가저항도 구하였다.

• 대한임상검사과학회지
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• 제45권1호
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• pp.16-20
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• 2013

Outbreaks of vancomycin-resistant enterococci (VRE) are being reported more frequently in many countries. While seven glycopeptide resistance genotypes have been described in Enterococci, vanA and vanB are the most common resistance genotypes. The aim of this study was to detect antibiotic susceptibilities of 23 Enterococcus faecium strains, which caused an outbreak in a University hospital by a disk diffusion test to investigate the presence of the species specific gene, and the resistant genotypes, vanA and vanB by duplex PCR. PCR for vanA and vanB was performed on 23 enterococci. Twenty three were identified as E. faecium and were tested positive for the vanA genotype. This study will report on the validation of a simple and accurate VRE detection method that can be easily incorporated into the daily routine of a clinical laboratory. Early detection of VRE strains, including those with susceptibility to vancomycin, is of paramount clinical importance as it allows rapid initiation of strict infection control practices, as well as the therapeutic guidance for confirmed infections. The PCR method developed in the present study is simple and reliable for the rapid characterization of VRE.

• 센서학회지
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• 제21권3호
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• pp.167-171
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• 2012

Ag- and Pd-loaded $SnO_2$ nanowire network sensors were prepared by the growth of $SnO_2$ nanowires via thermal evaporation, the coating of slurry containing $SnO_2$ nanowires, and dropping of a droplet containing Ag or Pd nanoparticles, and subsequent heat treatment. All the pristine, Pd-loaded and Ag-loaded $SnO_2$ nanowire networks showed the selective detection of $C_2H_5OH$ with low cross-responses to CO, $H_2$, $C_3H_8$, and $NH_3$. However, the relative gas responses and gas selectivity depended closely on the catalyst loading. The loading of Pd enhanced the responses($R_a/R_g$: $R_a$: resistance in air, $R_g$: resistance in gas) to CO and $H_2$ significantly, while it slightly deteriorated the response to $C_2H_5OH$. In contrast, a 3.1-fold enhancement was observed in the response to 100 ppm $C_2H_5OH$ by loading of Ag onto $SnO_2$ nanowire networks. The role of Ag catalysts in the highly sensitive and selective detection of $C_2H_5OH$ is discussed.

• 한국유체기계학회 논문집
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• 제19권4호
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• pp.39-42
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• 2016

A PFA lined ball valve, which is machined with fluorinated resin PFA to its inner part for improving corrosion resistance, non-stickness, heat-resistance, has been widely used to the chemical/pharmaceutical industries, the semiconductor/LCD manufacturing processes, etc. with the high purity chemicals as working fluid. EPA stated that 60% of all fugitive emissions come from the valve stem packing in a typical petroleum or chemical processing plant. They monitor regulated components for leaks and maintain seal performance at acceptable levels. Korean industrial standards only deals with the bubble test for in-line leakage of valves, which has the detectable leak rate of $10^{-4}$ [$mbar{\cdot}L{\cdot}s^{-1}$], therefore, it is not sufficient to check fugitive emissions. In this study, we conducted Helium leak detection from a PFA lined ball valve and evaluated fugitive emissions according to ISO 15848-1, which has the detectable leak rate of $10^{-9}$ [$mbar{\cdot}L{\cdot}s^{-1}$], for manufacturing the high-reliable PFA lined ball valves against fugitive emissions.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제18권4호
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• pp.1020-1041
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• 2024

With the development of covert communication technologies, the number of covert communication technologies using blockchain as a carrier is increasing. However, using the transaction amount of digital currency as a carrier for covert communication has problems such as low embedding rate, large consumption of transaction amount, and easy detection. In this paper, firstly, by experimentally analyzing the distribution of bitcoin transaction amounts, we determine the most suitable range of amounts for matrix decomposition. Secondly, we design a novel matrix decomposition method that can successfully decompose a large amount matrix into two small amount matrices and utilize the elements in the small amount matrices for covert communication. Finally, we analyze the feasibility of the novel matrix decomposition method in this scheme in detail from four aspects, and verify it by experimental comparison, which proves that our scheme not only improves the embedding rate and reduces the consumption of transaction amount, but also has a certain degree of resistance to detection.

• Journal of Yeungnam Medical Science
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• 제41권2호
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• pp.113-119
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• 2024

Background: Missing isoniazid (INH) resistance during tuberculosis (TB) diagnosis can worsen the outcomes of INH-resistant TB. The BD MAX MDR-TB assay (BD MAX) facilitates the rapid detection of TB and INH and rifampin (RIF) resistance; however, data related to its performance in clinical setting remain limited. Moreover, its effect on treatment outcomes has not yet been studied. Methods: We compared the performance of BD MAX for the detection of INH/RIF resistances to that of the line probe assay (LPA) in patients with pulmonary TB (PTB), using the results of a phenotypic drug sensitivity test as a reference standard. The treatment outcomes of patients who used BD MAX were compared with those of patients who did not. Results: Of the 83 patients included in the study, the BD MAX was used for an initial PTB diagnosis in 39 patients. The sensitivity of BD MAX for detecting PTB was 79.5%. The sensitivity and specificity of BD MAX for INH resistance were both 100%, whereas these were 50.0% and 95.8%, respectively, for RIF resistance. The sensitivity and specificity of BD MAX were comparable to those of LPA. The BD MAX group had a shorter time interval from specimen request to the initiation of anti-TB drugs (2.0 days vs. 5.5 days, p=0.001). Conclusion: BD MAX showed comparable performance to conventional tests for detecting PTB and INH/RIF resistances. The implementation of BD MAX as a diagnostic tool for PTB resulted in a shorter turnaround time for the initiation of PTB treatment.