• Journal of Applied Reliability
• /
• v.9 no.2
• /
• pp.71-80
• /
• 2009

This paper discusses the service life prediction methods for CFRP bar for concrete reinforcement using accelerated degradation tests. The relationship between performance degradation and the rate of a failure-causing chemical reaction is assumed for the temperature accelerated degradation tests. Methods of obtaining acceleration factors and predicting service life of the CFRP bar using the degradation model are presented.

• The Transactions of the Korean Institute of Electrical Engineers B
• /
• v.52 no.3
• /
• pp.116-123
• /
• 2003

This paper deals with an experimental study for on-line monitoring the performance of a universal motor for vacuum cleaner. Performance tests are conducted on the PC-based virtual instrumentation system designed using the graphical programming language LabVIEW. The proposed monitoring system is capable of performing real time measurement functions, including data acquisition, display, and analyses in the time and frequency domains, as well as data archiving. The measured mechanical and iron loss, voltage, current, input power, power factor, torque, and efficiency characteristics are presented as function of speed.

• Safety and Health at Work
• /
• v.10 no.1
• /
• pp.67-74
• /
• 2019

Background: Few studies have examined the effects of a forward rotating shift pattern on police employee performance and well-being. This study sought to compare sleep duration, cognitive performance, and vigilance at the start and end of each shift within a three-shift, forward rotating shift pattern, common in United Kingdom police forces. Methods: Twenty-three police employee participants were recruited from North Yorkshire Police (mean age, 43 years). The participants were all working the same, 10-day, forward rotating shift pattern. No other exclusion criteria were stipulated. Sleep data were gathered using both actigraphy and self-reported methods; cognitive performance and vigilance were assessed using a customized test battery, comprising five tests: motor praxis task, visual object learning task, NBACK, digital symbol substitution task, and psychomotor vigilance test. Statistical comparisons were conducted, taking into account the shift type, shift number, and the start and end of each shift worked. Results: Sleep duration was found to be significantly reduced after night shifts. Results showed a significant main effect of shift type in the visual object learning task and NBACK task and also a significant main effect of start/end in the digital symbol substitution task, along with a number of significant interactions. Conclusion: The results of the tests indicated that learning and practice effects may have an effect on results of some of the tests. However, it is also possible that due to the fast rotating nature of the shift pattern, participants did not adjust to any particular shift; hence, their performance in the cognitive and vigilance tests did not suffer significantly as a result of this particular shift pattern.

• Journal of the Society of Naval Architects of Korea
• /
• v.60 no.2
• /
• pp.110-119
• /
• 2023

The prediction of ship resistance performance is typically obtained by Computational Fluid Dynamics (CFD) simulations or model tests in towing tank. However, these methods are both costly and time-consuming, so hull-form designers use statistical methods for a quick feed-back during the early design stage. It is well known that results from statistical methods are often less accurate compared to those from CFD simulations or model tests. To overcome this problem, this study suggests a new approach using a Convolution Neural Network (CNN) with voxelized hull-form data. By converting the original Computer Aided Design (CAD) data into three dimensional voxels, the CNN is able to abstract the hull-form data, focusing only on important features. For the verification, suggested method in this study was compared to a parametric method that uses hull parameters such as length overall and block coefficient as inputs. The results showed that the use of voxelized data significantly improves resistance performance prediction accuracy, compared to the parametric approach.

• Journal of Radiation Protection and Research
• /
• v.28 no.4
• /
• pp.281-290
• /
• 2003

The KN-12 spent nuclear fuel transport cask, which is a Type B(U) package designed to comply with the requirements of Korea Atomic Energy Act[1], IAEA Safety Standards Series No.TS-R-1[2] and US 10 CFR Part 71[3], is designed for carrying up to 12 PWR spent fuel assemblies in a basket structure. The cask has been licensed in accordance with Korea Atomic Energy Act and was fabricated in Korea in accordance with the requirements of ASME B&PV Sec.III, Div.3[4]. The cask must maintain thermal integrity in accordance with the related regulations and be evaluated to verify that the thermal performance of the cask complies with the regulatory requirements. The temperatures of the cask and components were determined by using finite elements methods with a numerical tool, safety tests using an 1/8 height slice model of the real cask were conducted to demonstrate verification of the numerical tool and methods, and heat transfer tests for normal transport conditions were performed as a fabrication acceptance test to demonstrate the heat transfer capability of the cask.

• Asian Oncology Nursing
• /
• v.12 no.1
• /
• pp.52-60
• /
• 2012

Purpose: This study is to determine knowledge about early detection and risk perception of cancer according to taking cancer screening tests in the general population. Methods: The participants were 151 people aged 40 years or older. A questionnaire consisted of knowledge about early detection (warning signs, cancer screening methods, general knowledge for early detection), cancer risk perception and history of cancer screening during past 2 years. Results: The percentages of correct answers were 64.7% in knowledge about warning signs, 73.7% in knowledge of cancer screening tests and 80.1% in general knowledge for early detection. Participants had the highest knowledge about screening methods for stomach cancer and the lowest for liver and colon cancer. The level of risk perception was medium. The participants who participated in cancer screening showed lower risk perception than those who did not. There was no significant relationship between knowledge and performance of cancer screening. The primary reason for not participating in cancer screening was patient's perception of their own health. Conclusion: These results suggest that cancer risk perception can affect the performance of cancer screening and we need to study how to handle this problem. Additionally screening programs should focus on liver cancer and colon cancer.

• The Korean Journal of Applied Statistics
• /
• v.23 no.6
• /
• pp.1115-1124
• /
• 2010

Normal approximation methods under the null hypothesis of no difference are frequently used to test the two independent proportions in non-inferiority trials. However, these tests are not appropriate under the null hypothesis of non-zero difference. We review the likelihood score methods proposed by Miettinen and Nurminen, Farrington and Manning, and Gart and Nam and compare the performance of these tests. The simulation study shows that the likelihood score tests under the null hypothesis of non-zero difference have better performance at a Type I error and power than usual normal approximation methods.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2006.05a
• /
• pp.5-21
• /
• 2006

Traditional standards and specifications for concrete have largely been prescriptive, (or prescription-based), and can sometimes hinder innovation and in particular the use of more environmentally friendly concretes by requiring minimum cement contents and SCM replacement levels. In December 2004, the Canadian CSA A23.1-04 standard was issued which made provisions (a) for high-volume SCM concretes, (b) added new performance requirements for concrete, and (c) clearly outlined the requirements and responsibilities for use in performance-based concrete specifications. Also, in December 2003, the CSA A3000 Hydraulic Cement standard was revised. It (a) reclassified the types of cements based on performance requirements, with both Portland and blended cements meeting the same physical requirements, (b) allows the use of performance testing for assessing sulphate resistance of cementitious materials combinations, (c) includes an Annex D, which allows performance testing of new or non-traditional supplementary cementing materials. From a review of international concrete standards, it was found that one of the main concerns with performance specifications has been the lack of tests, or lack of confidence in existing tests, for judging all relevant performance concerns. Of currently used or available test methods for both fresh, hardened physical, and durability properties, it was found that although there may be no ideal testing solutions, there are a number of practical and useful tests available. Some of these were adopted in CSA A23.1-04, and it is likely that new performance tests will be added in future revisions. Other concerns with performance standards are the different perspectives on the point of testing for performance. Some concrete suppliers may prefer processes for both pre-qualifying the plant, and specific mixtures, followed only with testing only 'end-of-chute' fresh properties on-site. However, owners want to know the in-place performance of the concrete, especially with high-volume SCM concretes where placing and curing are important. Also, the contractor must be aware of, and share the responsibility for handling, constructability, curing, and scheduling issues that influence the in-place concrete properties.

• The Korean Journal of Health Service Management
• /
• v.9 no.1
• /
• pp.133-144
• /
• 2015

The Purpose of this study was to identify the educational effects of cardiopulmonary resuscitation using a PC skill-reporting system on the knowledge, Self-efficacy and skill performance ability of nursing students. The Participants were 57 nursing students from G metropolitan city, an experimental group of 29 subjects, and a control group of 28 students who were randomly sampled. Data were collected from 3 to 12 July of, 2013, and theory education and skill exposure programs for the experimental and control groups were conducted for 60 min. three times a week. The, PC skill-reporting system was used only with the experimental group. The collected data were analyzed with SPSS/WIN version 20.0 using ${\chi}^2$-tests, Fisher's exact probability tests, paired t-tests and t-tests. In the comparison of the two groups, the knowledge(t=-2.39, p=.022), self-efficacy (t=-3.45, p<.001) and skill performance ability(t=-2.52, p=.012) of the experiment group were significantly higher than those of the control group. Therefore, the adoption of instructional methods using a PC skill-reporting system is required to maximize the effects of cardiopulmonary resuscitation instruction.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2005.07a
• /
• pp.562-563
• /
• 2005

In case of aged porcelain, the failure in basic performance tests happened in cool-heat tests. Based on this characteristic, we studied the method predicting failure phenomena through more severe accelerated cool-heat ageing and accelerating thermal mechanical performance tests. Test results indicated that the thermal stress by temperature gradient was more severe parameter than thermal stress by quenching cycles within a category of standard or accelerating methods. And there is no the deterioration of statistic strength, but the deterioration of strength according to accelerating tests is serious.