• Geomechanics and Engineering
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• v.20 no.3
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• pp.175-189
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• 2020

A set of relatively simple five local shear and tension failure variables is presented and then implemented into a generalized poroelastic hydromechanical numerical model to analyze failure potential and stability of variably saturated geologic media. These five local shear and tension failure variables are formulated from geometrical relationships between the Mohr circle and the Mohr-Coulomb failure criterion superimposed with the tension cutoff, which approximate together the Mohr effective stress failure envelope. Finally, fully coupled groundwater flow and land deformation in two variably saturated geologic media, which are associated with a slope (Case 1) and a tunnel (Case 2), respectively, and their failure potential and stability are simulated using the resultant hydromechanical numerical model. The numerical simulation results of both cases show that shear and tension failure potential and stability of variably saturated geologic media can be analyzed numerically simply and efficiently and even better by using the five local shear and tension failure variables as a set than by using the conventional factors of safety against shear and tension failures only.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.5
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• pp.2101-2107
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• 2012

Treatment responses of $N_0$ stage nasopharyngeal carcinoma were firstly analyzed comprehensively to evaluate long term outcomes of patients and identify prognostic factors. A total of 610 patients with $N_0$ NPC, undergoing definitive radiotherapy to their primary lesion and prophylactic radiation to upper neck, were reviewed retrospectively. Concomitant chemotherapy was administrated to 65 out of the 610. Survival rates of the patients were calculated using the Kaplan-Meier method and compared by log-rank test. Prognostic factors were identified by the Cox regression model. The study revealed the 5-year and 10-year overall, disease-free, disease-specific, local failure-free, regional failure-free, locoregional failure-free and distant metastasis-free survival rates to be 78.7% and 66.8%, 68.8% and 55.8%, 79.9% and 70.4%, 81.2% and 72.5%, 95.8% and 91.8%, 78.3% and 68.5%, 88.5% and 85.5%, respectively. There were 192 patients experiencing failure (31.5%) after radiotherapy or chemoradiotherapy. Of these, local recurrence, regional relapse and distant metastases as the first event of failure occurred in 100 (100/610, 16.4%), 15(15/610, 2.5%) and 52 (52/610, 8.5%), respectively. Multivariate analysis showed that T stage was the only independent prognostic factor for patients with $N_0$ NPC (P=0.000). Late T stage (P=0.000), male (P=0.039) and anemia (P=0.007) were independently unfavorable factors predicting disease-free survival. After treatment, satisfactory outcome wasgenerally achieved in patients with $N_0$ NPC. Local recurrence represented the predominant mode of treatment failure, while T stage was the only independent prognostic factor for overall survival. Late T stage, male gender, and anemia independently predicted lower possibility of the disease-free survival.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.22 no.3
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• pp.191-201
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• 2010

The breakwaters are designed by considering the cost optimization because a human risk is seldom considered. Most breakwaters, however, were constructed without considering the cost optimization. In this study, the optimum return period, target failure probability and the partial safety factors were evaluated by applying the cost optimization to the rubble mound breakwaters in Korea. The applied method was developed by Hans F. Burcharth and John D. Sorensen in relation to the PIANC Working Group 47. The optimum return period was determined as 50 years in many cases and was found as 100 years in the case of high real interest rate. Target failure probability was suggested by using the probabilities of failure corresponding to the optimum return period and those of reliability analysis of existing structures. The final target failure probability is about 60% for the initial limit state of the national design standard and then the overall safety factor is calculated as 1.09. It is required that the nominal diameter and weight of armor are respectively 9% and 30% larger than those of the existing design method. Moreover, partial safety factors considering the cost optimization were compared with those calculated by Level 2 analysis and a fairly good agreement was found between the two methods especially the failure probability less than 40%.

• Journal of Korea Technology Innovation Society
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• v.15 no.1
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• pp.203-223
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• 2012

This study aimed to identify the factors of failure in cases where there was feasibility but was not successful in commercializing technology. For the study, 92 feasibility reports for new technologies were collected, and among these 4 studies that showed definite failure in commercialization of technology were analyzed in depth. Further analysis was based the factors pointed out by previous frameworks such as 1) discussion on success or failure in commercialization of technology, 2) that of venture company, and 3) valuation of technology studies. Previous studies pointed out success and failure factors as lack of funding, uncontrollable accidents, managing ability, inability for mass production and so forth, which had little difference to the pre-feasible evaluation of four cases. However, real reason was the lack of understanding technologies such as composition of technologies, production technologies required by stages, and lack of understanding of floor technologies. The misunderstandings were occurred regardless of CEO's experience and expertise. We did not touch the evaluation model of pre-feasibility studies, although we dealt with the failure of the pre-studies. The reason we do not generalize the results of this study is the fact that we dealt with only small cases.

• Journal of the Korea Concrete Institute
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• v.12 no.2
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• pp.21-30
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• 2000

In the Ultimate Strength Design, the design strength of a member is determined by multiplying the strength reduction factor to the nominal strength. This concept may be a reasonable approach, however it can not consider failure modes appropriately. Moreover, column design strength diagram show an abrupt change at a low level of axial load, which does not seem to be reasonable. This research compares the design strength determined by the strength resistance factors. As the material resistance factors for flexure and compression, 0.65 and 0.90 are proposed for concrete and steel, respectively. The design strength calculation process by applying material resistance factors addresses failure modes more effectively than by applying member strength reduction factor, and provides more resnable design strength for reinforced concrete flexural and compression members.

• Journal of Information Technology Services
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• v.8 no.4
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• pp.41-55
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• 2009

Due to the global business environments and severe competitions, SMEs have carried out IS projects for their competitive advantages. However, numerous organizations have faced with difficulties in the IS project management such as large amounts of IT expenses and uncertainties in project implementations. Thus, this study is intended to discover critical risk factors in the IS project management. To achieve this research goal, we have mailed questionnaires to SMEs and SI companies that experienced IS project failures and 63 usual data were collected. The result of analysis with step wise regression showed that 6 factors are related with IS project failures. The study contributes to the literature in two ways. First, this paper empirically identifies IS risk factors for SME manufactures. Second, this research result can be utilized as a checklist for the successful IS implementations. Limitations and future research topics are also discussed.

• Journal of the Korea Safety Management & Science
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• v.19 no.1
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• pp.169-179
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• 2017

The size of the market for SCM information systems have globally and steadily increased. And there are businesses that obtained innovative business performance by introducing SCM information systems. However, many businesses have still undergone trial and error in the process to introduce and operate SCM. As external factors including suppliers, customers, etc. and internal factors of businesses have been analyzed to be failure factors of executing SCM information systems, the businesses that try to introduce SCM information systems need to understand possible failure factors and establish the solutions. Therefore, this study tries to verify the diffusion of SCM information systems and effects on bullwhip effects. The study is expected to suggest empirical data that people will refer to the establishment of next counterstrategies according to the lapse of the period that systems are introduced based on theoretical bases related to the diffusion of SCM information systems.

• Childhood Kidney Diseases
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• v.25 no.1
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• pp.1-7
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• 2021

Chronic kidney disease (CKD) in children is associated with various complications, including poor growth and development, mineral bone disorder, cardiovascular disease, kidney failure, and mortality. Slowing down the progression of CKD is important since CKD is often not curable. Prospective cohort studies have been conducted to understand the progression and outcomes of CKD in children, and these studies have identified non-modifiable and modifiable risk factors. Recognition of known risk factors and early intervention are important to delay the progression of kidney function decline in children.

• Journal of Periodontal and Implant Science
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• v.50 no.6
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• pp.379-391
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• 2020

Purpose: The aims of this study were to evaluate the 5-year cumulative survival rate (CSR) of implants placed with guided bone regeneration (GBR) compared to implants placed in native bone, and to identify factors contributing to implant failure in regenerated bone. Methods: This retrospective cohort study included 240 patients who had implant placement either with a GBR procedure (regenerated bone group) or with pristine bone (native bone group). Data on demographic features (age, sex, smoking, and medical history), location of the implant, implant-specific features, and grafting procedures and materials were collected. The 5-year CSRs in both groups were estimated using Kaplan-Meier analysis. Risk factors for implant failure were analyzed with a Cox proportional hazards model. Results: In total, 264 implants in the native bone group and 133 implants in the regenerated bone group were analyzed. The 5-year CSRs were 96.4% in the regenerated bone group and 97.5% in the native bone group, which was not a significant difference. The multivariable analysis confirmed that bone status was not an independent risk factor for implant failure. However, smoking significantly increased the failure rate (hazard ratio, 10.7; P=0.002). Conclusions: The 5-year CSR of implants placed in regenerated bone using GBR was comparable to that of implants placed in native bone. Smoking significantly increased the risk of implant failure in both groups.

• Journal of the Korea Convergence Society
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• v.10 no.5
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• pp.369-375
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• 2019

Purpose: The purpose of this convergence study is to examine the factors influencing disease related knowledge in patients with congestive heart failure. Methods: A descriptive regression design was used and the participants were 100 patients with heart failure from one general hospital in 2015. Data analysis included .multiple regression. Results: The average scores were $9.59{\pm}1.77$ for disease related knowledge. The significant factors affecting disease related knowledge were severity(${\beta}=.32$, p<.001), duration of disease diagnosis(year) (${\beta}=.30$, p=.003). The regression model explained approximately 17.3 % of disease related knowledge. Conclusion: The findings recommend that nurses have to improve health related knowledge of patients with congestive heart failure by considering severity and duration of disease diagnosis.