• 품질경영학회지
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• 제29권1호
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• pp.41-46
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• 2001

The problem of trend change in the failure rate is great interest in the reliability and survival analysis. In this paper we develop a test statistic for testing whether or not the failure rate changes its trend based on a complete sample. Monte Carlo simulations are conducted to investigate the speed of convergence of the proposed test statistic.

• Journal of Korean Neurosurgical Society
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• 제39권5호
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• pp.385-388
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• 2006

An Intramedullary subependymoma of the spinal cord is a rare tumor with only 43 reported cases in the literature. Most of them are reported to be localized within the cervical spinal cord. We report a rare case of a thoracic spine intramedullary subependymoma in a 37-year-old female who presented with back pain and radiating leg pain. Subtotal resection and post-operative radiotherapy were performed. Subependymomas developing in the spinal cord are benign with a low proliferative potential. Complete resection of the tumor appears to be the optimal method for a complete cure. However aggressive surgery may cause severe neurological deficit. Therefore, if severe neurological deficits are expected after complete removal, a partial removal and postoperative radiation therapy is an alternative method for treatment in selected cases. A large-scale randomized study is mandatory to clarify the effectiveness of radiotherapy and to establish the recurrence rate and prognosis with respect to the surgical removal of these tumors.

• Asian-Australasian Journal of Animal Sciences
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• 제8권6호
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• pp.651-655
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• 1995

A simulation study on detection of linkage between genetic markers and QTL in backcross design was conducted. The effects of various sample sizes and the degree of QTL dominance on detention of linkage were examined by using a simple regression analysis. The results indicated that as sample size increased, the standard error of the estimated slope became smaller. When the dominance effect of QTL was complete, the estimated slope tended to be negative but was statistically not significant at all with type I error of greater than 50%. With complete linkage between genetic Marker and QTL, the estimated intercept value was smallest but the estimated slope was largest as expected. In most cases with various degree of dominance and sample sizes, when the actual recombination rate became larger, greater values were obtained for the slope except in the case of complete dominance of QTL.

• Radiation Oncology Journal
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• 제2권1호
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• pp.33-39
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• 1984

One hundred and twenty patients with brain metastases were seen and evaluated in the Dept. of Therapeutic Radiology, Seoul National University Hospital between 1979 and 1983. Of these, 90 Patients received whole brain irradiation with 2,000 ra4 in 1 week or 3,000 rad in 2 weeks for Palliative Purpose and 30 patients failed to complete the planned treatment. Carcinoma of the lung(44 cases), choriocarcinoma(11 cases), breast(8 cases) were common Primary tumors of 90 patients receiving planned treatment. Symptomatic subjective response was obtained in $92\%$ of Patients and meurologic functional improvement was obtained in $42\%$ of patients. Median survival was 6.4 months in patients with complete treatment an·d less than 2 months in Patients with incomplete treatment, overall survival rate at 1 year and 2 year were $26\%,\;16\%$ in Patients with complete treatment and $8\%,\;0\%$ in patients with incomplete treatment. Primary site, extent of metastases and interval from diagnosis of primary tumor to brain metastases were identified as prognostic factors.

• Communications for Statistical Applications and Methods
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• 제16권5호
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• pp.841-849
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• 2009

Let {$X_n$, n ${\ge}$ 1} be a negatively associated sequence of identically distributed random variables with mean zeros and positive finite variances. Set $S_n$ = ${\Sigma}^n_{i=1}\;X_i$. Suppose that 0 < ${\sigma}^2=EX^2_1+2{\Sigma}^{\infty}_{i=2}\;Cov(X_1,\;X_i)$ < ${\infty}$. We prove that, if $EX^2_1(log^+{\mid}X_1{\mid})^{\delta}$ < ${\infty}$ for any 0< ${\delta}{\le}1$, then $\lim_{{\epsilon}\downarrow0}{\epsilon}^{2{\delta}}\sum_{{n=2}}^{\infty}\frac{(logn)^{\delta-1}}{n^2}ES^2_nI({\mid}S_n{\mid}\geq{\epsilon}{\sigma}\sqrt{nlogn}=\frac{E{\mid}N{\mid}^{2\delta+2}}{\delta}$, where N is the standard normal random variable. We also prove that if $S_n$ is replaced by $M_n=max_{1{\le}k{\le}n}{\mid}S_k{\mid}$ then the precise rate still holds. Some results in Fu and Zhang (2007) are improved to the complete moment case.

• Journal of Information Processing Systems
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• 제10권4호
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• pp.568-580
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• 2014

To enhance the utilization of the traffic channels of a network (instead of allocating radio channel to an individual user), a channel or a group of channels are allocated to a user group. The idea behind this is the statistical distribution of traffic arrival rates and the service time for an individual user or a group of users. In this paper, we derive the blocking probability and throughput of a subscriber station of Worldwide Interoperability for Microwave Access (WiMAX) by considering both the connection level and packet-level traffic under a complete partition scheme. The main contribution of the paper is to incorporate the traffic shaping scheme onto the incoming turbulent traffic. Hence, we have also analyzed the impact of the drain rate of the buffer on the blocking probability and throughput.

• Journal of Chest Surgery
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• 제34권12호
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• pp.924-929
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• 2001

배경 : 흉벽을 침습한 비소세포암의 외과적 절제후의 장기 생존율에는 현재까지 림프절 전이, 완전 절제, 흉벽침습 깊이 등이 관여한다고 알려져 있다. 본 연구에서는 완전절제후의 예후에 관련된 요소들에 대해 알아보고자 한다. 대상 및 방법 : 1988년부터 1998년까지 원발성 비소세포암으로 수술을 받은 680명중, 벽측늑막과 흉벽을 침범한 경우에 완전절제를 실시한 55예(8.0%)에 대해 후향적 방법을 통해 분석하였다. 결과 : 29예(47.3%)에서 총괄절제를 시행하고 26예(52.7%)에서 늑막외절제를 실시하였다. 늑막외절제를 시행한 모든 예에서 침습정도는 벽측늑막에 국한되어 있었고, 총괄절제군에서는 9예(31.0%)에서 벽측늑막에 나머지 20예(69.0%)에서는 흉벽에의 침습이 병리학적으로 판명되었다. 수술사망은 3명에서 발생해 5.4%였으며, 추적은 100%에서 가능하였다. 전체환자군의 5년 생존율은 26%였으며, T3N0M0군의 생존율이 29%로 T3N2M0군의 18% 보다 높기는 하나 통계학적인 유의성은 없었다.(p=0.35) 흉벽침습 깊이정도에 따른 생존율은 림프절 전이의 유무에 관련없이 유의한 차이가 없었다.(p=0.99) 결론 : 흉벽을 침습한 T3 비소세포암에 대해 완전절제를 실시해 만족할 만한 생존율을 보였다. 림프절 전이 여부는 완전절제후의 생존율에 관여하는 바가 크나, 침습 깊이는 관여하는 정도가 덜하다.

• Imaging Science in Dentistry
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• 제38권1호
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• pp.23-27
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• 2008

Purpose: The aim of this study was to evaluate the change in the position of the mandibular condyle within articular fossa by a CBCT after wearing complete denture (CD). Materials and Methods: CBCT of 34 temporomandibular joints were taken from 9 male and 8 female patients with CB $Mercuray^{TM}$ (Hitachi, Japan) before and after wearing a CD for rehabilitation. Position of mandibular condyle within articular fossa at centric occlusion was evaluated with $Vimplant2.0^{TM}$ (CyberMed, Korea) on the central parasagittal view and curved panoramic coronal view of the condylar head. A statistical evaluation was done with SPSS. Results: The range of anteroposterior positional rate (AP) of condylar head within articular fossa was -16-5 and -10-12 respectively on the right and left sides. Before wearing CD, the AP rate showed discrepancy between right and left sides (p<0.05). After wearing CD, both condyles showed a tendency to decrease in posterior condylar position (right side; p<0.05). The average discrepancy between right and left side in mediolateral positional rate (MD) was 15.5 and 4.5 respectively before and after wearing CD. The improvement was observed in mediolateral relationship of both condylar heads after wearing CD (p< 0.01). Before wearing CD, the average horizontal angle of long axis of condylar head was $79.6{\pm}2.7^{\circ}\;and\;80.1{\pm}5.7^{\circ}$ respectively on the right and left sides. After wearing CD, both condyles were rotated in the same direction in average on axial plane. Conclusion: We observed with CBCT the significant clinical evidence in case of positional change of mandibular condyle after wearing complete denture.

• Journal of Korean Medical Science
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• 제33권43호
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• pp.239.1-239.12
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• 2018

Background: We described a novel multi-step retinal fundus image reading system for providing high-quality large data for machine learning algorithms, and assessed the grader variability in the large-scale dataset generated with this system. Methods: A 5-step retinal fundus image reading tool was developed that rates image quality, presence of abnormality, findings with location information, diagnoses, and clinical significance. Each image was evaluated by 3 different graders. Agreements among graders for each decision were evaluated. Results: The 234,242 readings of 79,458 images were collected from 55 licensed ophthalmologists during 6 months. The 34,364 images were graded as abnormal by at-least one rater. Of these, all three raters agreed in 46.6% in abnormality, while 69.9% of the images were rated as abnormal by two or more raters. Agreement rate of at-least two raters on a certain finding was 26.7%-65.2%, and complete agreement rate of all-three raters was 5.7%-43.3%. As for diagnoses, agreement of at-least two raters was 35.6%-65.6%, and complete agreement rate was 11.0%-40.0%. Agreement of findings and diagnoses were higher when restricted to images with prior complete agreement on abnormality. Retinal/glaucoma specialists showed higher agreements on findings and diagnoses of their corresponding subspecialties. Conclusion: This novel reading tool for retinal fundus images generated a large-scale dataset with high level of information, which can be utilized in future development of machine learning-based algorithms for automated identification of abnormal conditions and clinical decision supporting system. These results emphasize the importance of addressing grader variability in algorithm developments.

• 한국병원경영학회지
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• 제26권3호
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• pp.43-55
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• 2021

Purposes: The purpose of this study is to confirm the effect of mother's nationality on screening rates for infants and children health screening. We intend to find out if there is a difference in health level between infants of multicultural families and infants of domestic families, and contribute to policies to enhance future national health levels by providing information on them. Methodology: Data for those who received the first infant and children health screening between 2012 and 2018 were obtained from the National Health Insurance Service(NHIS) DB. Frequency analysis, chi-square test and logistic regression analysis were performed with the SAS 9.4 program, and the case where all the 1st to 3rd checkups were completed was defined as type I, and the case of all the 1st to 7th checkups completed, type II. Findings: Complete screening rates for type I and type II were 45.8% and 20.0%, respectively. Especially, complete screening rate of infants whose mothers nationality is foreign is only 3-4th of that of domestic mothers, and it also differed according to nationality. Practical Implications: The difference in the screening rate according to the mother's nationality is likely to lead to a health gap between multicultural families and domestic families. It is necessary to promote and encourage proper monitoring and health management through continuous health screening for infants and children.