• Clinical and Experimental Reproductive Medicine
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• v.29 no.2
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• pp.77-82
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• 2002

Objective : This study is to evaluate the efficacy of intracytoplasmic sperm injection (ICSI) for previous fertilization failure with conventional in vitro fetrtilization (IVF), compared with ICSI for male factor. Method: The author analyzed the 3 years of clinical experience with ICSI retrospectively, between the conventional IVF failure group (IVF failure) and male factor group (male factor). Surgically retrieved epididymal or testicular spermatozoa for ICSI were excluded. The IVF failure group was 13 cycles of 6 patients and male factor group was 30 cycles of 15 patients. Results: The fertilization rates of the IVF failure group and male factor group were 63% and 66% respectively (p=0.635). The clinical pregnancy rates of the both group were 23.1% and 26.7% (p=0.804), and that of live birth rates were 15.4% and 13.3% (p=0.858). There were no significant difference between the two groups. Conclusion: The author concluded that ICSI can overcome previous fertilization failure, with the same fertilization and clinical pregnancy rates seen in patients with male factor.

• Journal of Korean Institute of Industrial Engineers
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• v.29 no.2
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• pp.145-149
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• 2003

We consider the estimation of failure rate and acceleration factor under type-I censoring without using acceleration model when testing is conducted in only one highly accelerated condition. Failure times of an item are assumed to be exponentially distributed. It is also assumed that the uncertainty about the acceleration factor, the failure time contraction ratio between accelerated condition and use condition, can be modeled by the uniform or gamma prior distribution of appropriate parameters. We respectively use Bayes and maximum likelihood approaches to estimate acceleration factor and failure rate in the use condition. An example is given to show how the method can be applied.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.25 no.2
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• pp.12-17
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• 2017

Manned aircraft structural design is based on structural safety factor of 1.5, and this safety factor is equivalent to a probability of failure of between 10-2 and 10-3. The target failure probability of FARs is between 10-6 and 10-9 per flight according to aircraft type. NATO released STANAG 4703 to established the airworthiness requirements for small UAV which is less than 150kg. STANAG 4703 requires the Target Level of Safety according to MTOW. The requirements of failure probability for small UAV is between 10-4 and 10-5. In this paper, requirements of airworthiness certification for small UAV were investigated and the relationship of safety factors to the probability of structural failure is analyzed to reduce measure of safety factor and structural weight of unmanned aircraft.

• Geomechanics and Engineering
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• v.6 no.1
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• pp.17-31
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• 2014

This paper investigates the development of failure surfaces induced by an embankment on soft marine clay deposits and the characteristics of such surfaces through numerical simulations and its comparative study with monitoring results. It is well known that the factor of safety of embankment slopes is closely related to the vertical loading, including the height of the embankment. That is, an increase in the embankment height reduces the factor of safety. However, few studies have examined the relationship between the lateral movement of soft soil beneath the embankment and the factor of safety. In addition, no study has investigated the distribution of the pore pressure coefficient B value along the failure surface. This paper conducts a continuum analysis using finite difference methods to characterize the development of failure surfaces during embankment construction on soft marine clay deposits. The results of the continuum analysis for failure surfaces, stress, displacement, and the factor of safety can be used for the management of embankment construction. In failure mechanism, it has been validated that a large shear displacement causes change of stress and pore pressure along the failure surface. In addition, the pore pressure coefficient B value decreases along the failure surface as the embankment height increases. This means that the rate of change in stress is higher than that in pore pressure.

• Geomechanics and Engineering
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• v.22 no.4
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• pp.319-328
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• 2020

This paper investigates the effect of the width of failure and tension crack (TC) on the stability of cohesive-frictional soil slopes in three dimensions. Working analytically, the slip surface and the tension crack are considered to have spheroid and cylindrical shape respectively, although the case of tension crack having planar, vertical surface is also discussed; the latter was found to return higher safety factor values. Because at the initiation of a purely rotational slide along a spheroid surface no shear forces develop inside the failure mass, the rigid body concept is conveniently used; in this respect, the validity of the rigid body concept is discussed, whilst it is supported by comparison examples. Stability tables are given for fully drained and fully saturated slopes without TC, with non-filled TC as well as with fully-filled TC. Among the main findings is that, the width of failure corresponding to the minimum safety factor value is not always infinite, but it is affected by the triggering factor for failure (e.g., water acting as pore pressures and/or as hydrostatic force in the TC). More specifically, it was found that, when a slope is near its limit equilibrium and under the influence of a triggering factor, the minimum safety factor value corresponds to a near spherical failure mechanism, even if the triggering factor (e.g., pore-water pressures) acts uniformly along the third dimension. Moreover, it was found that, the effect of tension crack is much greater when the stability of slopes is studied in three dimensions; indeed, safety factor values comparable to the 2D case are obtained.

• Asia pacific journal of information systems
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• v.11 no.2
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• pp.205-221
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• 2001

The previous BPR success factor research assumes that a success factor is responsible for both the success and failure of the BPR implementation. This paper proposes that a BPR success factor is not necessarily a failure factor, i.e., success and failure of BPR implementation are two distinct phenomena that possess different sets of causal factors. The paper also proposes that the factors are different in terms of the degree and type of influence they exert on the BPR implementation. An empirical research was conducted to validate the propositions. The research results indicate that the BPR success and failure have different causal factor sets, and that the factor influence manifests in different realms and domains. The implications of the research are discussed at the end.

• Proceedings of the Korean Geotechical Society Conference
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• 1999.03a
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• pp.277-284
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• 1999

This study describes the influence factors related to slope failure pattern and dimension in the southern Kyounggi area. Intrusive and metamorphic rocks are distributed in the study area. Geological condition, rainfall property and slope geometry are influence on slope failure characteristics in the study we& Geological factors related to slope failure are rock type, geological structure and weathering condition. Because of deep soil (RS-CW) depth of granite region, circular failure type is major failure pattern in granite region. Almost granite slopes with circular or surface failure pattern are failed during heavy rainfall season. But typical wedge failure type related to geological structure factor is a main failure pattern of metamorphic rock slope. Additionally failure dimension is influenced by geological factors and several factors, i.e. natural slope condition, failure type, rainfall intensity and etc. failure height/width ratio and thickness/length ratio of granite slope are 0.88 and 0.23. But the ratios of metamorphic rock slope are 1.36 and 0.19.

• Proceedings of the Korean Geotechical Society Conference
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• 2003.03a
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• pp.509-512
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• 2003

Our country is serious difference of precipitation seasonally and about 66% of yearly mean rainfall is happening in concentration rainfall form between September on June. It requires consideration because of a lot of natural disasters by this downpour are produced. Slope failure is happened by artificial factor of creation of slope according to the land development, fill slope etc. and natural factor of rainfall, topography, nature of soil, soil quality, rock floor. Usually, Direct factor of failure slope is downpour. In this study, the Slope about among 55 places happened failure by downpour investigated occurrence position, geological etc and executed and inquire into character of rainfall connected with failure slope. Among character of rainfall, executed analysis about Max. hourly rainfall and cumulative rainfall of place that failure slope is situated and grasped the geological character of failure slope. Through this, inquire to character of failure slope by rainfall and take advantage of basis study for Hazard map creation.

• Journal of Korean Elementary Science Education
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• v.36 no.4
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• pp.439-446
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• 2017

The purpose of this study was to compare Grit, failure tolerance and psychological well-being between elementary science gifted and general students. The subjects of this study were 48 science gifted students and 70 general students in the 5th and 6th grade of elementary school in Gyeonggi province. The results of this study were as follows: First, Grit, failure tolerance and psychological well-being of science gifted students were higher than those of the general students, there was a statistically significant difference. Second, science gifted students showed higher correlation between grit and failure tolerance, grit and psychological well-being than general students. Grit of science gifted students had a positive correlation with all sub-factors of academic failure tolerance and psychological well-being. In general students, there was a positive correlation with all sub-factors of Grit, academic failure tolerance, and psychological well-being except for the emotion sub-factor of academic failure tolerance. Thirdly, as a result of the regression analysis on the elements of failure tolerance affecting the Grit, science gifted students showed emotional factor but general students had behavioral factors. Also, as a sub-factor of psychological well-being on Grit, both science gifted and general students showed autonomy.

• Journal of Industrial Technology
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• v.3
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• pp.53-63
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• 1983

The probability of failure is used to analyze the reliability of three dimensional slope failure, instead of conventional factor of safety. The strength parameters are assumed to be normal variated and beta variated. These are interval estimated under the specified confidence level and maximum likelihood estimation. The pseudonormal and beta random variables are generated using the uniform probability transformation method according to central limit theorem and rejection method. By means of a Monte-Carlo Simulation, the probability of failure is defined as; Pf=M/N N : Total number of trials M : Total number of failures Some of the conclusions derived from the case study include; 1. Three dimensional factors of safety are generally much higher than 2-D factors of safety. However situations appear to exist where the 3-D factor of safety can be lower than the 2-D factor of safety. 2. The F3/F2 ratio appears to be quite sensitive to c and ${\phi}$ and to the shape of the 3-D shear surface and the slope but not to be to the unit weight of soil. 3. In cases that strength parameters are assumed to be normal variated and beta variated, the relationships between safety factor and the probability of failure are fairly consistent, regardless of the shape of the 3-D shear surface and the slope. 4. As the c-value is increased, the probability of failure for the same safety factor is increased and as the ${\phi}-value$ is increased, the probability of failure for the same safety factor is decreased.