• Structural Monitoring and Maintenance
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• v.1 no.1
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• pp.111-130
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• 2014

The increased use of carbon fiber reinforced polymer (CFRP) in retrofitting reinforced concrete (RC) members has led to the need to develop non-destructive techniques that can monitor and characterize the unique damage mechanisms exhibited by such structural systems. This paper presented the damage characterization results of six CFRP retrofitted RC beam specimens tested in the laboratory and monitored using acoustic emission (AE). The focus of this study was to continuously monitor the change in AE parameters and analyze them both qualitatively and quantitatively, when brittle failure modes such as debonding occur in these beams. Although deterioration of structural integrity was traceable and can be quantified by monitoring the AE data, individual failure mode characteristics could not be identified due to the complexity of the system failure modes. In all, AE was an effective non-destructive monitoring tool that can trace the failure progression in RC beams retrofitted with CFRP. It would be advantageous to isolate signals originating from the CFRP and concrete, leading to a more clear understanding of the progression of the brittle damage mechanism involved in such a structural system. For practical applications, future studies should focus on spectral analysis of AE data from broadband sensors and automated pattern recognition tools to classify and better correlate AE parameters to failure modes observed.

• Proceedings of the KSME Conference
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• 2000.11a
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• pp.286-291
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• 2000

The reactor pressure vessel is usually cladded with stainless steel to prevent corrosion and radiation embrittlement, and number of subclad cracks have been found during an in-service-inspection. Therefore assessment for subclad cracks should be made for normal operating conditions and faulted conditions such as PTS. Thus, in order to find the optimum fracture assessment procedures for subclad cracks under a pressurized thermal shock condition, in this paper, three different analyses were performed, ASME Sec. XI code analysis, an LEFM(Liner elastic fracture mechanics) analysis and an EPFM(Elastic plastic fracture mechanics) analysis. The stress intensity factor and the Maximum $RT_{NDT}$ were used for characterizing. Analysis based on ASME Sec. XI code does not completely consider the actual stress distribution of the crack surface, so the resulting Maximum allowable $RT_{NDTS}$ can be non-conservative, especially for deep cracks. LEFM analysis, which does not consider elastic-plastic behavior of the clad material, is much more non-conservative than EPFM analysis. Therefore, It is necessary to perform EPFM analysis for the assessment of subclad cracks under PTS.

• Journal of Korea Society of Digital Industry and Information Management
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• v.12 no.1
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• pp.71-79
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• 2016

The main security threats in MANET are integrity and non-repudiation. In the meantime, a lot of secure routing protocols have been designed in order to block these security threats. In this paper, partnership-based authentication technique is proposed in order to provide participation exclusion of network and non-repudiation for the nodes. The proposed technique is a technique that participates in data communication for only the nodes receiving the authentication through the authentication process for the nodes. For this, the proposed technique is largely consists of two steps. The first step is the process that issued the certificate after the reliability for the nodes participating in the network is evaluated. And in the second step, the key exchange agreement with the neighbor nodes is performed and data communication is made after setting security path with responding nodes. The level of security in data transmission is improved because the process of path setting is performed through cooperation with a neighboring nodes having high reliability during the course of these two steps. The superiority of proposed technique in this paper was confirmed through the comparative experiment.

• Biomedical Science Letters
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• v.25 no.4
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• pp.339-347
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• 2019

Saururus chinensis (SC) belongs to the dicotyledonous plants, and its roots, leaves and flowers are white, so it is named three hundred and seconds. It is mainly distributed in Korea, China and Japan. In Korea, it is a native plant distributed in Jejudo and Jirisan areas. It has been known to improve blood circulation, anticarcinogenic effects and purge. However, studies of the efficacy on digestive system is few. This study was conducted to evaluate the effects of oral administered-SC extract in loperimide-induced constipation rats. The amount, weight and water content of the stools were measured. The number and type of stools in the large intestines were measured, and the amount of intestinal mucus was analyzed by serological analysis and histologic special staining. The severity of constipation in SC groups was significantly less than that in control group (non-SC rats). Digital Image processing also showed weaker inflammation on the large intestines of SC groups than that of control group (non-SC group). Especially, with increased dose dependent manner of SC extract, the amount and integrity of intestinal mucus increased. These results suggest that SC extract may prevent the symptoms of constipation.

• Journal of the Korean Society of Propulsion Engineers
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• v.5 no.1
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• pp.76-81
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• 2001

A structural test of the wind turbine rotor blade is to evaluate the uncertainty of design due to selection of material, design concepts, production processes and so on, and their possible impacts on the structural integrity. In the full-scale static strength test, the measuring parameters are strain and displacements vs. loads, weight and the center of gravity. In order to simulate the aerodynamics load, the three-point loading method is applied. There is slight difference between the measured results and the predicted results for the reference fiber volume fraction of 60% . However, the agreement between the measured results and the predicted results with the actual fiber volume fraction of 52.5% is good. Even though a slightly non-linearity from 80% loading to 100% loading exists, a linear static solution is sufficient for the design purpose due to te small amount of non-linearity. Comparison between measured and predicted strain results at the maximum thickness positions of the blade profile for 0.236R(5.56m), 0.493R(11.59m) and 0.574R(13.43m), under 20%, 40%, 60%, 80% and 100% loadings for the upper part of the blade. The predicted values are in good agreement with the measured values.

• Proceedings of the Korean Information Science Society Conference
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• 2001.10a
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• pp.700-702
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• 2001

As computers and networks become popular, distributing information on the Interment is common in our daily life. Also, the explosion of the Internet, of wireless digital communication and data exchange on Internet has rapidly changed the way we connect with other people. But secure mall is gamins popularity abroad and domestically because of their nature of prodding security. That is. it has been used a variety of fields such as general mail and e-mail for advertisement But, As the data transmitted on network can be easily opened or forged with simple operations. Most of existing e-mall system don't have any security on the transmitted information. Thus, security mail system need to provide security including message encryption, content integrity, message origin authentication, and non-repudiation. In this paper, we design implement secure mall system with non-repudiation service and encryption capability to provide services for certification of delivery and certification of content as well as the basic security services.

• Proceedings of the Korea Information Processing Society Conference
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• 2000.04a
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• pp.318-323
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• 2000

The SSL(Secure Socket Layer) protocol is one of the mechanism widely used in the recent network system. The improved information security mechanism based on the SSL is designed in this paper. There are important four information security services. The first is the authentication service using the Certificate offered from the SSL(Secure Socket Layer), the second is the message confidentiality service using the DES encryption algorithm, the third is the message integrity service using Hash function, and the fourth is Non-repudiation service. Therefore, information could be transferred securely under the information security mechanism including Non-repudiation service especially designed in this paper.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.6
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• pp.2989-2993
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• 2016

The commonest cancer in Egyptian females occurs in the breast cfDNA is a non-invasive marker for tumor detetion and prognostic assessment in many types of cancer including breast cancer. This study aimed to assess the role of cfDNA and its fragmentation pattern in breast cancer prognosis and treatment response. Forty female patients with malignant breast tumors and a comparable group of healthy blood donors were enrolled prospectively. cfDNA levels and fragmentation patterns were investigated after cfDNA extraction, gel electrophoresis and gel analysis. The percentage of breast cancer patients positive for cfDNA (92.5%) was significantly higher than that of controls (55%). Also, mean concentration of cfDNA was significantly higher than in the control group (P<0.05). Most Her-2 positive patients had long cfDNA fragments, this being significant as compared to Her-2 negative patients (P<0.05). Metastasis was also positively linked to significantly higher cfDNA (P<0.05) and the mean cfDNA integrity index was significantly higher in non-responders compared to treatment responders (P<0.05). In conclusion, both qualitative and quantitative aspects of cfDNA and its different fragments in breast cancer patients could be related to prognosis, metastasis and treatment response. Long cfDNA fragments could be particularly useful for prediction purposes.

• Journal of Research and Publication Ethics
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• v.2 no.2
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• pp.5-10
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• 2021

Purpose: Ethical behaviors become more salient when researchers utilize face-to-face interviews and observation with vulnerable groups or communities, which may be unable to express their emotions during the sessions. The present research aims to investigate ethical behaviors while conducting research have resonance due to the deep nature of observation and interview data collection methods. Research design, data and methodology: The present research obtained non-numeric (Textual) data based on prior literature review to investigate Ethical Conducts in Qualitative Research. Non-numeric data differs from numeric data in how the data is collected, analyzed and presented. It is important to formulate written questions and adopt them what the method claims for the researcher to understand the studied phenomenon. Results: Our findings show that while conducting qualitative research, researchers must adhere to the following ethical conducts; upholding informed consent, confidentiality and privacy, adhering to beneficence's principle, practicing honesty and integrity. Each ethical conduct is discoursed in detail to realize more information on how it impacts the researcher and research participants. Conclusions: The current authors concludes that five ethical conducts are important for realizing extensive and rich information during qualitative research and may be exploited in implementing research policies for researchers utilizing observation and interviews methods of data collection.

• Smart Structures and Systems
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• v.23 no.1
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• pp.61-69
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• 2019

Offshore structures are generally exposed to harsh environments such as strong tidal currents and wind loadings. Monitoring the structural soundness and integrity of offshore structures is crucial to prevent catastrophic collapses and to prolong their lifetime; however, it is intrinsically challenging because of the difficulties in accessing the critical structural members that are located under water for installing and repairing sensors and data acquisition systems. Virtual sensing technologies have the potential to alleviate such difficulties by estimating the unmeasured structural responses at the desired locations using other measured responses. Despite the usefulness of virtual sensing, its performance and applicability to the structural health monitoring of offshore structures have not been fully studied to date. This study investigates the use of virtual sensing of offshore structures. A Kalman filter based virtual sensing algorithm is developed to estimate responses at the location of interest. Further, this algorithm performs a multi-sensor data fusion to improve the estimation accuracy under non-stationary tidal loading. Numerical analysis and laboratory experiments are conducted to verify the performance of the virtual sensing strategy using a bottom-fixed offshore structural model. Numerical and experimental results show that the unmeasured responses can be reasonably recovered from the measured responses.