• Proceedings of the Computational Structural Engineering Institute Conference
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• 2004.10a
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• pp.550-557
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• 2004

In this paper, structural damage in PSC bridges is monitored by using model-based damage detection methods. First numerical experiments on the test structure are described. Dynamic responses of the test structures are obtained fur several damage scenarios. The change in natural frequency and the change in nude shape curvature are selected as features to represent the states of the structure. Next a damage localization algorithm from monitoring the changes in natural frequency is outlined. Also, the damage localization algorithm from monitoring the changes in nude shapes is outlined. Finally, the damage localization algorithms are used to predict damage in the test structure. The results of the analysis indicate that the model-based damage detection methods correctly predicted damage in the test structure.

• Journal of Korean Academy of Nursing
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• v.40 no.2
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• pp.151-160
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• 2010

Purpose: The purpose of this study was to evaluate the effects of teaching method using Standardized Patients (SPs) on nursing competence, self-directed learning readiness, and problem solving ability-focusing on subcutaneous insulin injection. Methods: This research was a nonequivalent control group non-synchronized post-test design. The subjects consisted of 62 junior nursing students at E University. Scenarios to train SPs and checklists to evaluate the students' competence were developed by our research team. The experimental group (n=31) participated in the teaching class using SPs. The control group (n=31) received traditional practice education. The collected data were analyzed with descriptive analysis, $\chi^2$/Fisher's exact test, t-test, Pearson's correlation coefficient, and Cronbach's $\alpha$ using SPSS WIN 14.0 Program. Results: The mean scores of competence, self-directed learning readiness, and problem solving were significantly higher in the experimental group than the control group. Conclusion: As confirmed by this research findings, the teaching method using SPs was more effective than the traditional method to improve junior nursing students' competence, self-directed learning readiness, and problem solving. Therefore, It is necessary to develop a various of scenarios and to testify their effectiveness.

• Korean Journal of Agricultural and Forest Meteorology
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• v.25 no.4
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• pp.376-386
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• 2023

Due to climate changes, landslide hazards in the Republic of Korea (hereafter South Korea) continuously increase. To establish the effective landslide mitigation strategies, such as erosion control works, landslide hazard estimation in the long-term perspective should be proceeded considering the influence of climate changes. In this study, we examined the change in landslide-damaged areas in South Korea responding to climate change scenarios using the multivariate regression method. Data on landslide-damaged areas and rainfall from 1981-2010 were used as a training dataset. Sev en indices were deriv ed from rainfall data as the model's input data, corresponding to rainfall indices provided from two SSP scenarios for South Korea: SSP1-2.6 and SSP5-8.5. Prior to the multivariate regression analysis, we conducted the VIF test and the dimension analysis of regression model using PCA. Based on the result of PCA, we developed a regression model for landslide damaged area estimation with two principal components, which cov ered about 93% of total v ariance. With climate change scenarios, we simulated landslide-damaged areas in 2030-2100 using the regression model. As a result, the landslide-damaged area will be enlarged more than the double of current annual mean landslide damaged area of 1981-2010; It infers that landslide mitigation strategies should be reinforced considering the future climate condition.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.15 no.2
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• pp.25-31
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• 2007

The ADS-B test is a program that is examining the use of ADS-B, especially CDTI for aircraft surveillance in Korea. The ADS-B project is to provide operational benefits to Air Traffic Controllers in the selected area and provide first operational experience of ADS-B in ATCS environment of South Korea. For these objectives, the ground station has installed in Tae-An airport, Participation in the Ground Test has been limited to 4 Aircraft of Hanseo University which are installed ADS-B equipment. Ground test is a test that is examining on the movement area of Tae-An Airport on the assumption that the visibility is below weather minia of the airport. This test have been experimented as pre-arranged scenarios. In view of the results achieved, it has shown that the volume of voice communication between controller and pilot are remarkably reduced. Additionally, as both pilots and air traffic controllers are able to see the positions of traffic in the vicinity of the aircraft, the test has demonstrated that it is possible for ADS-B not only to decline the controller's workload, but also to enhance pilot situational awareness in the near future.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.6
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• pp.2139-2151
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• 2014

Embedded system testing, especially long-term reliability testing, of flash memory solutions such as embedded multi-media card, secure digital card and solid-state drive involves strategic decision making related to test sample size to achieve high test coverage. The test sample size is the number of flash memory devices used in a test. Earlier, there were physical limitations on the testing period and the number of test devices that could be used. Hence, decisions regarding the sample size depended on the experience of human testers owing to the absence of well-defined standards. Moreover, a lack of understanding of the importance of the sample size resulted in field defects due to unexpected user scenarios. In worst cases, users finally detected these defects after several years. In this paper, we propose that a large number of potential field defects can be detected if an adequately large test sample size is used to target weak features during long-term reliability testing of flash memory solutions. In general, a larger test sample size yields better results. However, owing to the limited availability of physical resources, there is a limit on the test sample size that can be used. In this paper, we address this problem by proposing a self-adaptive reliability testing scheme to decide the sample size for effective long-term reliability testing.

• Journal of Auto-vehicle Safety Association
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• v.14 no.3
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• pp.6-16
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• 2022

Recent, the issue of the fourth industrial revolution triggered by technological advances has changed the automobile industry centered on internal combustion engines, and quantitative growth of the global automobile market, which has grown rapidly, has been slowing since 2015. These advances in technology are expected to develop beyond the advanced driver assistance system to autonomous driving technology. According to SAE-J3016 published by the Society of Automotive Engineers, the technology of autonomous vehicles is divided into a total of six stages according to the driver's intervention and automation level from 0 to 5. Securing safety for autonomous vehicles is important. But, research on safety evaluation theory and autonomous vehicle evaluation method based on real vehicle test is insufficient. In this study, the longitudinal distance theory equation and continuous test scenario were proposed for the test method of autonomous vehicles for fixed targets, and the real vehicle test was conducted. When comparing the theoretical values compared to the measured values, it was determined that it was reliable with a minimum error rate of 0.484% and a maximum error rate of 7.391%. Using the proposed theoretical equation, it is judged that it can be used as a safety evaluation method in an environment where real vehicle test is not possible because it can grasp the trend in the longitudinal direction in the development stage.

• Journal of the Korea Institute of Military Science and Technology
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• v.27 no.3
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• pp.375-386
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• 2024

Autonomous weapon systems act according to artificial intelligence-based judgement based on recognition through various sensors. Test and evaluation for various scenarios is required depending on the characteristics that artificial intelligence-based judgement is made. As a part of this approach, this paper proposed a LiDAR point cloud augmentation method for mixed-reality based test and evaluation. The augmentation process is achieved by mixing real and virtual LiDAR signals based on the virtual LiDAR synchronized with the pose of the autonomous weapon system. For realistic augmentation of test and evaluation purposes, appropriate intensity values were inserted when generating a point cloud of a virtual object and its validity was verified. In addition, when mixing the generated point cloud of the virtual object with the real point cloud, the proposed method enhances realism by considering the occlusion phenomenon caused by the insertion of the virtual object.

• Journal of Ocean Engineering and Technology
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• v.30 no.2
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• pp.100-108
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• 2016

A high-pressure ball valve was developed, and both the structural strength and sealing performance were assessed based on a nonlinear finite element analysis. Different parts were modeled with solid elements and assembled, taking into account both contact and sliding effects. Three different loading scenarios were analyzed, including a high-pressure closure test and fire and shell test conditions. The structural safety of each part was checked under each loading condition, and the sealing performance was also investigated to validate the performance of the valve.

• Communications for Statistical Applications and Methods
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• v.27 no.5
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• pp.579-588
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• 2020

Obligor defaults are cross-sectionally correlated as obligors share common economic conditions; in addition obligors are longitudinally correlated so that an economic shock like the IMF crisis in 1998 lasts for a period of time. A longitudinal correlation should be used to construct statistical scenarios of stress test with which we replace a type of artificial scenario that the banks have used. We propose a Bayesian model to accommodate such correlation structures. Using 402 obligors to a domestic bank in Korea, our model with a dynamic correlation is compared to a Bayesian model with a stationary longitudinal correlation and the classical logistic regression model. Our model generates statistical financial statement under a stress situation on individual obligor basis so that the genearted financial statement produces a similar distribution of credit grades to when the IMF crisis occurred and complies with Basel IV (Basel Committee on Banking Supervision, 2017) requirement that the credit grades under a stress situation are not sensitive to the business cycle.

• The KSFM Journal of Fluid Machinery
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• v.17 no.1
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• pp.22-27
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• 2014

The test system for the performance of the water-mist extinguishing system in the railway vehicle is equipped and the details of the system are introduced. The three scenarios using different fire sources and performance criteria for the water-mist systems on railway vehicles are also introduced. Three different type of the nozzle at same operating pressure are evaluated. Amount of water-mist distribution is measured by many baskets on the bottom of the test room. Temperature on the ceil and the tree of the test room is measured during the tests that are used for the judgement of the performance on the water-mist extinguishing system.