• Journal of The Korean Society of Agricultural Engineers
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• v.61 no.1
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• pp.75-83
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• 2019

Fruit bagging is a traditional way to produce high-quality fruit and to prevent damage from insects and diseases. Growing pears by non-bagging is concerned about the damage from insect, it can be controlled by installing a insect net facility. Wind load should be considered to design the insect net facility because it has the risk of collapse due to the strong wind. So we carried out wind tunnel test for measurement of drag force, where the insect net with porosity about 65% is selected as an experimental subject. As a result of the test, drag force was measured to be 244.14 N when insect net area and wind speed are $1m^2$ and 22.7 m/s respectively. And, drag coefficients for the insect net were found to be about 0.55~0.57, which may be used as the preliminary data to design the insect net facilities at the orchard.

• Tunnel and Underground Space
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• v.16 no.2 s.61
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• pp.146-155
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• 2006

The target slope of this study, formed during the construction of highway, is the very high infinite slope where sliding began along the discontinuity. Although an attempt was made to stabilize the upper part of the slope by installing the rock anchors, large scale failure was occurred at the lower part if the reinforced area. Afterwards, subsequent failures were observed two times. To investigate the cause of the failure, residual shear strength was measured by performing the direct shear test of rock specimen of the site. The anchor design was based on the pull-out test. Considering the slope surface where the undulation was severe and the variation of strength was very large, buttressing was used to obtain the required anchoring capacity.

• Journal of the Korea Institute of Building Construction
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• v.2 no.3
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• pp.139-146
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• 2002

As the bentonite is main material to prevent from collapse of drilling hole at underground excavation works, it is increased using quantity on construction industry day by day. But, the discarded bentonite that is over using at underground excavation works is caused various environmental trouble as soil and water pollution est. This study aims to propose a foundamental report for pozzolan reaction of discarded Bentonite powder by heat-treatment and cooling as concrete mineral admixture. To find out pozzolan reaction ability of discarded Bentonite powder by indirect cooling & cooling using of water after heat-treatment, the experiments are excuted Phenolphtalein test, setting test, pH test and the analysis by X-ray diffractor. As a result of this study, discarded Bentonite powder can be utilized as concrete mineral admixture by heat-treatment and especially, pozzolan reaction ability of discarded Bentonite powder is superior to the situation of 50$0^{\circ}C$~$700^{\circ}C$, 60min.

• Nuclear Engineering and Technology
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• v.50 no.1
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• pp.190-202
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• 2018

Maintaining the integrity of the major equipment in nuclear power plants is critical to the safety of the structures. In particular, the soundness of the piping is a critical matter that is directly linked to the safety of nuclear power plants. Currently, the limit state of the piping design standard is plastic collapse, and the actual pipe failure is leakage due to a penetration crack. Actual pipe failure, however, cannot be applied to the analysis of seismic fragility because it is difficult to quantify. This paper proposes methods of measuring the failure strain and deformation angle, which are necessary for evaluating the quantitative failure criteria of the steel pipe elbow using an image measurement system. Furthermore, the failure strain and deformation angle, which cannot be measured using the conventional sensors, were efficiently measured using the proposed methods.

• Steel and Composite Structures
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• v.24 no.4
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• pp.441-453
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• 2017

In Y-shaped eccentrically braced frame fabricated with high strength steel (Y-HSS-EBF), link uses conventional steel while other structural members use high strength steel. Cyclic test for a 1:2 length scaled one-bay and one-story Y-HSS-EBF specimen and shake table test for a 1:2 length scaled three-story Y-HSS-EBF specimen were carried out to research the seismic performance of Y-HSS-EBF. These include the failure mode, load-bearing capacity, ductility, energy dissipation capacity, dynamic properties, acceleration responses, displacement responses, and dynamic strain responses. The test results indicated that the one-bay and one-story Y-HSS-EBF specimen had good load-bearing capacity and ductility capacity. The three-story specimen cumulative structural damage and deformation increased, while its stiffness decreased. There was no plastic deformation observed in the braces, beams, or columns in the three-story Y-HSS-EBF specimen, and there was no danger of collapse during the seismic loads. The designed shear link dissipated the energy via shear deformation during the seismic loads. When the specimen was fractured, the maximum link plastic rotation angle was higher than 0.08 rad for the shear link in AISC341-10. The Y-HSS-EBF is a safe dual system with reliable hysteretic behaviors and seismic performance.

• International Journal of Naval Architecture and Ocean Engineering
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• v.10 no.6
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• pp.711-729
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• 2018

This paper reports on the experimental investigations on the failure modes of ring-stiffened cylinder models subjected to external hydrostatic pressure. Nine models were welded from general structural steel. The shells were initially formed by cold-rolling, and flat-bar ring frames were welded to the shell. The hydrostatic pressure tests were conducted by using water as the medium in pressure chambers. The details of the preparation and main test were briefly explained. The investigation identified the consequence of the structural failure modes, including: shell yielding, local shell buckling between ring stiffeners, overall buckling of the shell together with the stiffeners, and interactive buckling mode combining local and overall buckling. In addition, the ultimate strengths were predicted by using existing design codes. Non-linear numerical computations were also conducted by employing the actual imperfection coordinates. Finally, accuracy and reliability of the predictions of design formulae and numerical were substantiated with the test results.

• Geomechanics and Engineering
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• v.28 no.1
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• pp.1-10
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• 2022

In Korea, accidents related to the collapse of deteriorated aging reservoirs occur every year. The grouting method is generally applied to reinforce an aging reservoir. However, when using this method, different reinforcing effects appear depending on the ground conditions. Thus, new construction methods and materials capable of providing consistent reinforcing effects are required. In this study, the direct shear test (DST), model test, and simulation analysis were performed to evaluate the impact of surface stabilizers, generally used to reinforce roads, rivers, and slopes of roads, applied using surface curtain walls on aging reservoirs. The DST results indicate that when the surface stabilizer was mixed with in-situ soil, the increase in cohesion was the highest at a mixing ratio of 9%. No changes in the friction angle were evident; therefore, 9% was determined to be the optimal mixing ratio. In addition, the model test and simulation analysis showed that when 9% of the surface stabilizer was mixed and applied to the aging reservoir, the seepage quantity of water and the saturated area were reduced by approximately 42% and 73%, respectively. Moreover, the comprehensive analysis of results showed that the grouting method could be completely replaced by surface stabilizers applied through surface curtain walls because the technique could secure stability by decreasing the seepage in the aging reservoir.

• Journal of the Society of Disaster Information
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• v.16 no.3
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• pp.594-601
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• 2020

Purpose: The purpose of the present study was to identify factors affecting anxiety about disaster damage potential in Gyonggi-do and evacuation behavior that influences evacuation behavior. Method: Multiple regression analysis was performed to test the hypothesis and to analyze the influence of anxiety about disaster damage potential and perceived stress, and analyzed similarity in correspondence between age and anxiety about disaster damage potential. Results: The anxiety about disaster damage potential of a group vulnerable to safety and anxiety about disaster damage potential of disaster system collapse were perceived in close proximity. Disaster system collapse, evacuation life, and natural disasters were found to be factors affecting perceived stress. Stress and natural disasters were found to be influencing factors on evacuation behavior. Conclusion: The necessity of managing stress was confirmed since anxiety about natural disaster damage potential and stress affect evacuation behavior. The recent experiences of heavy rain disasters indicate that the anxiety about disaster damage potential is expected to increase. The findings also indicate the importance of preventive planning and psychological management to manage the anxiety about disaster damage potential.

• The Korean Journal of Applied Statistics
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• v.14 no.1
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• pp.39-57
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• 2001

Categorical data has sometimes misclassification errors. If this data will be analyzed, then estimated cell probabilities could be biased and the standard Pearson X2 tests may have inflated true type I error rates. On the other hand, if we regard wellclassified data with misclassified one, then we might spend lots of cost and time on adjustment of misclassification. It is a necessary and important step to ask whether categorical data is misclassified before analyzing data. In this paper, when data is misclassified at one of two variables for two-dimensional contingency table and marginal sums of a well-classified variable are fixed. We explore to partition marginal sums into each cells via the concepts of Bound and Collapse of Sebastiani and Ramoni (1997). The double sampling scheme (Tenenbein 1970) is used to obtain informations of misclassification. We propose test statistics in order to solve misclassification problems and examine behaviors of the statistics by simulation studies.

• Journal of Veterinary Clinics
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• v.23 no.3
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• pp.329-333
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• 2006

A 9-month-old neutered male German Shepherd dog was referred with the primary complaint of episodic collapse. Apparent abnormal findings were not observed in physical examination, routine biochemistry, and diagnostic imaging studies. In the 12-lead surface ECG after collapse, the dog showed frequent ventricular premature contractions (VPCs) with torsade de pointes. The frequency of VPCs was reduced after lidocaine infusion. Based on the history, findings in event recordings oi the ECG and lidocaine response test, the dog was diagnosed as inherited malignant ventricular tachyarrhythmia. Although the dog was initially responded to oral sotalol therapy, the dog was died suddenly. This report described the first case of malignant ventricular tachyarrhythmia of German Sheperd in Korea.