• Radiation Oncology Journal
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• v.11 no.1
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• pp.83-90
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• 1993

During the period from January, 1975, to June, 1989, one hundred patients with histopathologically proven polymorphic reticulosis in the upper respiratory tract were treated with radiation therapy and the analysis of treatmemt results was undertaken. One hundred patients (69 males, 31 females) with a mean age of 46 years (range 12-79 years) were presented. Nasal cavity was the most frequent site of involvement ($56{\%}$), and 44 cases had multifocal sites of involvement. The incidence of cervical lymph node metastasis at initial diagnosis was $24{\%}$. Staging was determined by Ann-Arbor classification, retrospectively. The number of patients of stage IE, IIE, IIIE and IVE were 35, 60, 1, and 4, respectively. The overall 5 year actuarial survival rates were $38.4{\%}$. The difference in 5 year survival rates between patients with stage IE and IIE, with solitary and multiple, with CR and PR after irradiation were significant statistically. For the analysis of failure patterns, failure sites include the following: local failure alone (30/55=$54.6{\%}$), systemic failure alone (9/55=$16.4{\%}$), both local and systemic failure (16/55=$29.0{\%}$). Retrograde slide review was available in 29 cases of PMR with respect to histopathologic bases, and immunohistochemical studies were performed using MT1 and DACO-UCHL-1 as T-cell markers, MB2 as a B-cell marker and alpha-1-antichymotrypsin as a histiocytic markers. All that 29 cases showed characteristic histologic features similar to those of peripheral T-cell lymphoma and showed positive reactio to the T-cell marker. These findings suggest strongly that quite a significant portion of PMR may be in fact T-cell lymphoma.

• Korean Circulation Journal
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• v.52 no.12
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• pp.878-886
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• 2022

Background and Objectives: Moderate aortic stenosis (AS) confers a surprisingly adverse prognosis, approaching that of severe AS. The objective of this study was to describe the clinical course of patients with moderate AS with evidence of concomitant heart failure manifesting as elevated brain natriuretic peptide (BNP) levels. Methods: This is a single-center, retrospective cohort study of 332 patients with elevated BNP. 165 patients with moderate AS were compared with 167 controls with none-mild AS. The Median follow-up duration was 3.85 years. The primary outcome was a composite endpoint of all-cause hospitalizations and all-cause mortality. Results: BNP levels were 530 and 515 pg/mL in the study and the control groups, respectively. Moderate AS had significantly higher rates of primary composite endpoint in both univariate analysis (hazard ratio [HR], 1.50; 95% confidence interval [CI], 1.14-1.97; p=0.004) and adjusted analysis (HR, 1.45; 95% CI, 1.05-2.01; p=0.02). Moderate AS had 1.41 (95% CI, 1.18-1.69; p<0.001) times more all-cause hospitalization per patient-year of follow-up compared to controls in the univariate model. After adjustment for significant covariates, moderate AS remained an independent predictor of all-cause hospitalizations (incidence rate ratio [IRR], 1.45; 95% CI, 1.18-1.79; p=0.005). Furthermore, moderate AS was significantly associated with higher all-cause hospitalization rates in both heart failure with reduced ejection fraction (IRR, 1.33; 95% CI, 1.02-1.75; p=0.038) and heart failure with preserved ejection fraction [IRR], 1.31; 95% CI, 1.03-1.67; p=0.026). Conclusions: Moderate AS in conjunction with elevated BNP portends a significantly worse prognosis than those without moderate AS and should be followed closely.

• Journal of Cerebrovascular and Endovascular Neurosurgery
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• v.25 no.1
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• pp.13-18
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• 2023

Objective: Mechanical thrombectomy (MT) is an effective treatment for patients suffering from acute ischemic stroke secondary to large vessel occlusion. However, recanalization failure rates of interventions were about 20% in literature studies. We report our experience of unsuccessful MT with a focus on technical reasons. Methods: From December 2010 to June 2021, six hundred eight patients with acute ischemic stroke due to large artery occlusion received MT using a stent retriever with or without an aspiration catheter in our institution. We divided the reasons for failure into six categories. We analyzed the reasons for failure by dividing our experience time into 3 periods. Results: A total of 608 cases of thrombectomy for large vessel occlusion were identified in the study period. The successful recanalization rate was 90.4%. In most of the cases (20/57, 35%), the thrombus persisted despite several passes, and the second most common cause was termination of the procedure even after partial recanalization (10/57, 18%). Similar proportions of in-stent occlusion, distal embolization, and termination due to vessel rupture were observed. On analysis of three periods, the successful recanalization rate improved over time. Conclusions: MT fails due to various reasons, and intracranial artery stenosis is the main cause of MT failure. With the development of rescue techniques, the failure rate has gradually decreased. Further development of new devices and techniques could improve the recanalization rates.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.49 no.1
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• pp.13-20
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• 2023

Objectives: Ultra-wide implants may be used as a replacement if existing implants fail. This study was conducted to evaluate the factors influencing the prognosis and failure of ultra-wide implants. Patients and Methods: This study evaluated whether sex, age, site, diameter, length, additional surgery, implant stability (primary and secondary), and reason for ultra-wide implant placement affect the 5-year survival and success rates and marginal bone loss (MBL) of ultra-wide implants. Seventy-eight ultra-wide implants that were placed in 71 patients (39 males and 32 females) from 2008 to 2010 were studied. One-way ANOVA analysis was conducted to evaluate the statistical significance of MBL according to the patient's sex, implant site, and diameter. Independent sample t-tests were used to determine the statistical significance of MBL analysis which was used to determine the significance of the 5-year success and survival rates related to the variables. One-way ANOVA was conducted to evaluate the statistical significance of sex, implantation site, diameter, and MBL. Independent sample t-tests were used to evaluate the correlation between implantability and MBL for implantation reasons, while additional surgery, length, and Kaplan-Meier analysis were used to evaluate 5-year survival and success rates. Results: The mean age of patients was 54.2 years with a survival rate of 92.3% and a success rate of 83.3% over a mean 97.8-month period of observation. MBL averaged 0.2 mm after one year of prosthetic function loading and 0.54 mm at the time of final observation. Success rates correlated with primary stability (P=0.045), survival rates correlated with secondary stability (P=0.036), and MBL did not correlate with any variables. Conclusion: Ultra-wide implants can be used to achieve secure initial fixation in the maxillary and mandibular molar regions with poor bone quality or for alternative purposes in cases of previous implant failure.

• Convergence Security Journal
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• v.6 no.3
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• pp.145-153
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• 2006

Infinite failure NHPP models for a record value satisfies mode proposed in the literature exhibit either monotonic increasing or monotonic decreasing failure occurrence rates per fault. In this paper, propose comparative study of software reliability model using Erlang distribution, Rayleigh and Gumbel distribution. Equations to estimate the parameters using maximum likelihood estimation of infinite failure NHPP model based on failure data collected in the form of interfailure times are developed. For the sake of proposing distribution, we used to the special pattern. Analysis of failure data set using arithmetic and Laplace trend tests, goodness-of-fit test, bias tests is presented.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.12 no.6
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• pp.1-9
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• 2013

The studies on the shortest path algorithms based on Dijkstra algorithm has been done continuously to decrease the time for searching. $A^*$ algorithm is the most represented one. Although fast searching speed is the major point of $A^*$ algorithm, there are high rates of failing in search of the shortest path, because of complex and irregular networks. The failure of the search means that it either did not find the target node, or found the shortest path, witch is not true. This study proposed $A^*$ algorithm applying method that can reduce searching failure rates, preferentially organizing the relations between the starting node and the targeting node, and appling it in reverse according to the organized path. This proposed method may not build exactly the shortest path, but the entire failure in search of th path would not occur. Following the developed algorithm tested in a real complex networks, it revealed that this algorithm increases the amount of time than the usual $A^*$ algorithm, but the accuracy rates of the shortest paths built is very high.

• Transactions of Materials Processing
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• v.21 no.2
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• pp.113-118
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• 2012

Magnesium sheet alloys possess limited plastic formability at room temperature but their formability is substantially improved at elevated temperatures and optimum strain rates. In the present paper, three different types of failure criteria, namely, strain-based, stress-based, and work-based criteria, are compared for their applicability to warm press forming of magnesium sheet alloys. Warm deep-drawing experiments were conducted on AZ31 alloy sheet, and the results were used to assess the strength and weakness of the failure criteria.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.11a
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• pp.1014-1017
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• 2000

Reliability engineering is regarded as the major and important roll for all industry. And advanced manufacturing systems with high speed and intelligent have been developed for the betterment of machining ability. In this study, we have systemized evaluation of reliability for machinery system. We proposed the reliability assessment and design review method using analyzing critical units of high speed and intelligent machine system. In addition, we have not only designed and developed test bed system for acquiring reliability data, but also have constructing WEB system for suppling reliability which is provided in design phase. From this study, we will expect to guide and introduce the reliability engineering in developing and processing phase of high quality product.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2004.04a
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• pp.232-236
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• 2004

The fracture characteristics of unidirectional composite single-lap bonded joints were investigated experimentally and numerically. The effects of bonding method, surface roughness, bondline thickness and the existence of fillet on the failure characteristics and strength of bonded single-lap joints were evaluated experimentally. The failure process, failure mode and the behavior of load-displacement curve was apparently different according to bonding method. The failure load of the specimen co-cured without adhesive was definitely superior to other types of specimens but the specimens co-cured with adhesive film had a less strength than secondary bonded specimens. In the secondary bonded specimens, the lower value of surface roughness and existence of fillet improved the strength of specimens. The strain energy release rates calculated by geometric nonlinear finite element analyses and Virtual Crack Closure Technique for the secondary bonded specimens considering the three types of initial cracks - comer crack, edge crack and delamination crack - were consistent with the test results.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.7 no.1
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• pp.22-31
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• 2008

The operating window method is a novel approach in quality improvement. But it has not received deserved attention in academic research. If a critical factor for competing failure modes can be identified, the probability of failure can be reduced by widening the operating window of this factor. Traditional SN ratio for the operating window advocated by Taguchi has a critical shortcoming, which has been derived under the assumption that failure rates are determined by the operating window factor only. A new metric for robustness is given for the operating window method, which has relaxed the restrictive assumption of Taguchi's SN ratio. And procedures for determining optimal conditions based on the new metric is presented. The effectiveness of the proposed approach over the traditional practice is tested with the aid of a wave soldering process.