• Computers and Concrete
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• v.33 no.5
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• pp.481-496
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• 2024

Internal erosion around pipes can lead to the failure of earth dams through various mechanisms. This study investigates the displacement patterns in earth dam models under three different failure modes due to internal erosion, using digital image correlation (DIC) methods. Three failure modes—erosion along a pipe (FM1), pipe leakage leading to soil erosion (FM2), and erosion in a pipe due to defects (FM3)—are analyzed using two- and three-dimensional image- processing techniques. The internal displacement of the cross-sectional area and the surface displacement of the downstream slope in the dam models are monitored using an image acquisition system. Physical model tests reveal that FM1 exhibits significant displacement on the upper surface of the downstream slope, FM2 shows focused displacement around the pipe defect, and FM3 demonstrates increased displacement on the upstream slope. The variations in internal and surface displacements with time depend on the segmented area and failure mode. Analyzing the relationships between internal and surface displacements using Pearson correlation coefficients reveals various displacement patterns for the segmented areas and failure modes. Therefore, the image-based characterization methods presented in this study may be useful for analyzing the displacement distribution and behavior of earth dams around pipes, and further, for understanding and predicting their failure mechanisms.

• Korean Journal of Head & Neck Oncology
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• v.21 no.1
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• pp.26-31
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• 2005

Backgrounds and Objectives: Squamous cell carcinomas of the oral cavity(SCOC) in TNM stage I & II have relatively high chance to be cured compared to those in the advanced stage, but sometimes result in the treatment failure with poor prognosis. There have been few reports on the patterns of failure and the clinical courses for SCOC in stage I & II after the failure of initial treatment. This study is directed at identifying the clinical outcomes of stage I & II SCOC and the salvage rate after initial treatment and suggesting an optimal level of treatment by analyzing the patterns of failure. Material and Methods: The medical records of 36 patients with SCOC, initially diagnosed between 1995 and 2001 as TNM stage I & II were reviewed retrospectively. The patterns of failure, salvage treatment, clinical courses, and the survival of these subjects were analyzed. The minimum follow-up period of no-evidence of disease(NED) was 12 months with an average of 32.2 months. Results: Overall rate of the treatment failure in SCOC of stage I & II was 41. 7%(15/36 cases). Most of the treatment failure in the subjects with stage I tumors occurred in regional lymph node. Local failure was the most frequent form of failure in the subjects with stage II tumors after wide excision of primary tumor with elective neck dissection and/or radiation therapy. No significant correlation was noted between the safety margin and the local failure. Elective neck dissections in stage I & II SCOC had a tendency to reduce regional failure (p=0.055). The salvage rates at 24 months were 85.7% in stage I, and 37.5% in stage II. The 3-year survival rate after the failure of initial treatment was 55.0%. Conclusion: SCOC of stage I & II after the failure of initial treatment showed poor prognosis despite of the salvage treatments. This study implies that the elective neck dissections for regional lymph node should be required for SCOC of stage I & II to reduce the treatment failure.

• Radiation Oncology Journal
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• v.35 no.4
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• pp.359-367
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• 2017

Purpose: This study sought to identify potential candidates for adjuvant radiotherapy and patterns of regional failure in patients who underwent curative-intent surgery for gallbladder cancer. Materials and Methods: Records for 70 patients with gallbladder cancer who underwent curative resection at a single institution between 2000 and 2016 were analysed retrospectively. No patients received adjuvant radiotherapy. Initial patterns of failure were evaluated. Regional recurrence was categorized according to the definitions of lymph node stations suggested by the Japanese Society of Hepato-Biliary-Pancreatic Surgery. Results: Median follow-up was 23 months. Locoregional recurrence as any component of first failure occurred in 29 patients (41.4%), with isolated locoregional recurrence in 13 (18.6%). Regional recurrence occurred in 23 patients, and 77 regional recurrences were identified. Commonly involved regional stations were #13, #12a2, #12p2, #12b2, #16a2, #16b1, #9, and #8. Independent prognostic factors for locoregional recurrence were ${\geq}pT2$ disease (hazard ratio [HR], 5.510; 95% confidence interval [CI], 1.260-24.094; p = 0.023) and R1 resection (HR, 6.981; 95% CI, 2.378-20.491; p < 0.001). Conclusion: Patients with pT2 disease or R1 resection after curative surgery for gallbladder cancer may benefit from adjuvant radiotherapy. Our findings on regional recurrence may help physicians construct a target volume for adjuvant radiotherapy.

• Proceedings of the Korea Society for Simulation Conference
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• 2003.11a
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• pp.147-151
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• 2003

Yield enhancement in semiconductor fabrication is important. Even though DRAM yield loss may be attributed to many problems, the existence of defects on the wafer is one of the main causes. When the defects on the wafer form patterns, it is usually an indication for the identification of equipment problems or process variations. In this paper describes the techniques to automatically classify a failure pattern using a fail bit map.

• Proceedings of the IEEK Conference
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• 2003.07b
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• pp.703-706
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• 2003

Yield enhancement in semiconductor fabrication is important. It is ideal to prevent all the failures. However, when a failure occurs, it is important to quickly specify the cause stage and take countermeasure. The automatic method of failure pattern extraction from fail bit map provides reduced time to analysis and facilitates yield enhancement. This paper describes the techniques to automatically classifies a failure pattern using a fail bit map, a new simple schema which facilitates the failure analysis.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.41 no.5
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• pp.240-245
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• 2015

Objectives: This study was performed to evaluate patterns of failure time after insertion, failure rate according to loading time after insertion, and the patterns of failure after loading. Materials and Methods: A total of 331 mini-implants were classified into the non-failure group (NFG) and failure group (FG), which was divided into failed group before loading (FGB) and failed group after loading (FGA). Orthodontic force was applied to both the NFG and FGA. Failed mini-implants after insertion, ratio of FGA to NFG according to loading time after insertion, and failed mini-implants according to failed time after loading were analyzed. Results: Percentages of failed mini-implants after insertion were 15.79%, 36.84%, 12.28%, and 10.53% at 4, 8, 12, and 16 weeks, respectively. Mini-implant failure demonstrated a peak from 4 to 5 weeks after insertion. The failure rates according to loading time after insertion were 13.56%, 8.97%, 11.32%, and 5.00% at 4, 8, 12, and 16 weeks, respectively. Percentages of failed mini-implants after loading were 13.79%, 24.14%, 20.69%, and 6.9% at 4, 8, 12, and 16 weeks, respectively. Conclusion: Mini-implant stability is typically acquired 12 to 16 weeks after insertion, and immediate loading can cause failure of the mini-implant. Failure after loading was observed during the first 12 weeks.

• Geomechanics and Engineering
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• v.39 no.1
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• pp.13-26
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• 2024

Studies pertaining to the seismic bearing capacity analysis of skirted footings using the pseudo-static approach for estimation of the earthquake force in association with finite element method have been presented in this paper. An attempt has been made to explain the behaviors of the skirted footings by means of failure patterns obtained for rigid and flexible skirts. The skirts enhance the seismic bearing to some extent with an increase in seismic loading, after which it decreases nonlinearly. The effectiveness of skirts increases initially to some extent with an increase in seismic loading, after which it decreases nonlinearly. Other parameters that inversely affect the effectiveness of skirts are the depth of footing and the internal friction angle of the soil. The detailed finite element analysis regarding the various failure patterns of skirted footings under seismic forces shows the failure mechanism changes from a general shear failure to local shear failure with an increase in seismic force. An opposite trend has been observed with the increase in the angle of internal friction of the soil. The obtained analysis results suggest that a rigid skirted footing behaves similar to a conventional strip footing under seismic and static loadings. The excessive deflection of flexible skirts under combined gravity and seismic loading renders them relatively ineffective than rigid skirts.

• 한국데이터정보과학회:학술대회논문집
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• 2002.06a
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• pp.89-95
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• 2002

This paper considers the problem of estimating paramaters of the bivariate exponential distribution with a loaction parameter for a two-component shared parallel system using component data from system-level life test terminated at the time of the prespecified number of system failure. In the system-level life testing, there are three patterns of failure types; 1) both component failed 2) both component censored 3) one is failed and the other is censored. In the third case, we assume that the failure time might be known or unknown. The maximum likelihood estimators are obtained for the case of known/unknown failure time when the other component is censored.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.11a
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• pp.261-264
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• 2006

Deformability of RC members in shear after flexural yielding is limited and controlled by governing failure modes and material strength. Shear strength of members in D-regions has been explained by a direct load path (direct strut or arch action) and indirect load path (fan action or truss action). Indirect load path including truss action and fan action rely on bond along tension ties. Generally, superposition of two actions results in total shear strength when shear failure modes control. The ultimate deformation depends on controlling failure modes and thereby, their force transfer patterns. Proposed models are capable of explaining of limited deformability of RC members in D-regions.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.26-27
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• 2006

Capping mechanisms during the compaction of pharmaceutical powders were explored. Both experimental and numerical investigations were performed. For the experimental study, an X-ray Computed Microtomography system has also used to examine the internal failure patterns of the tablets produced using a compaction simulator. Finite element (FE) methods have also been used to analyse the powder compaction. The experimental and numerical studies have shown that the shear bands developed at the early stage of unloading appear to be responsible for the occurrence of capping. It has also been found that the capping patterns depend on the compact shape.