• Communications for Statistical Applications and Methods
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• 제26권2호
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• pp.163-173
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• 2019

Simon's two-stage designs are frequently used in phase II single-arm trials for efficacy studies. A concern of safety studies is too many patients who experience an adverse event. We show that Simon's two-stage designs for efficacy studies can be similarly used to design a two-stage safety study by modifying some of the design parameters. Given the type I and II error rates and the proportion of adverse events experienced in the first stage cohort, we prescribe a procedure whether to terminate the trial or proceed with a stage 2 trial by recruiting additional patients. We study the relationship between a two-stage design with a safety endpoint and an efficacy endpoint as well as use simulation studies to ascertain their properties. We provide a real-life application and a free R package gen2stage to facilitate direct use of two-stage designs in a safety study.

• 한국안전학회지
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• 제25권3호
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• pp.34-39
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• 2010

Unidirectional Carbon Fiber Reinforced Plastics (CFRP) are advanced materials which combine the characteristics of the light weight, high stiffness and strength. For those reasons, the use of the unidirectional CFRP has increased in jet fighters, aerospace structures. However, unidirectional CFRP composites have a lot of problems, especially delamination, compared with traditional materials such as steels and aluminums, and so forth. Therefore, the interlaminar fracture toughness for a laminate CFRP composite is very important. In this study, The mode II interlaminar fracture toughness was measured by using center notched flexure(CNF) test specimen. The CNF specimens using unidirectional carbon prepreg were fabricated by a hot-press with the gage pressure and temperature controller. And three kinds of a/L ratio was applied to these specimens. Here, we discuss the relations of the crack growth and the mode II interlaminar fracture under the four point bending CNF test. From the results, we shows that mode II interlaminar was occurred when the more $a_0$/L ratio, the less load. And $G_{IIC}$ also were obtained as 5.33, 2.9 and $0.58kJ/m^2$ according to $a_0$/L ratio=0.2, 0.3 and 0.4.

• 한국안전학회지
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• 제31권2호
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• pp.26-32
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• 2016

In previous studies on LPG siting in Korea, the scope have not included the probability of the secondary events of adjacent LPG tanks or structures from an explosion source. Therefore, it is essential to first identify the phenomenon which can be caused by BLEVE and then, properly assess their effects to each target including secondary event. In this study, we calculated the effects from a potential BLEVE of 15 ton LPG tank causing damages of storage tanks (LPG), structures and human using Phast ver. 6.7 and then suggested three risk zones (Zone I, II, III) assuming the consequences such as overpressure, heat radiation and missile effect by fragments. Zone I and II are divided at the line of 50% occurrence of the secondary event. Zone II and III are divided by Individual Risk(IR). The zone approach in this study can be used for more effective and safer Land Use Planning (LUP) for the future.

• 제품안전
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• 통권115호
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• pp.44-49
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• 2003

• 제품안전
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• 통권115호
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• pp.42-43
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• 2003

• 제품안전
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• 통권250호
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• pp.14-17
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• 2014

• 안전기술
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• 제137호
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• pp.58-59
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• 2009

• 제품안전
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• 통권181호
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• pp.64-67
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• 2009

• 제품안전
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• 통권117호
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• pp.35-39
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• 2003

• 제품안전
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• 통권120호
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• pp.34-39
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• 2003