• Asian Pacific Journal of Cancer Prevention
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• 제15권8호
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• pp.3561-3566
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• 2014

Background: Recurrent nasopharyngeal carcinoma (NPC) after previous radiotherapy is challenging. There is no standard approach for salvage treatment. Here we present toxicity and treatment results for recurrent NFC patients who underwent fractionated stereotactic radiotherapy (FSRT) as second line radiotherapy (RT). Materials and Methods: Between April 2009 and July 2012, 24 patients, with a male to female ratio of 3:1, were treated with CykerKnife$^{(R)}$ FSRT for recurrent NFC in our institution. Seven out of 24 patients had metastatic recurrent disease. Median age was 53 years (range, 20-70 years). Initial RT dose was 70Gy. The time period between initial RT and FSRT was a median of 33.2 months. The median prescription dose for FSRT was 30Gy (range, 24-30 Gy) in a median of 5 fractions (range, 4-6). Results: The median follow-up for all patients was 19.5 months (IQR: 12.2.-29.2 months). The locoregional control; progression free survival and overall survival (OS) rates for 1-, 2- and 3-year were 64%, 38%, 21%; 60%, 30%, 17% and 83%, 43%, 31%, respectively. Median OS for the entire cohort was 22 months (95% CI: 16.5-27.5). On multivariate analysis recurrent tumor stage was the only prognostic factor for OS (p=0.004). One patient exhibited grade III temporal lobe necrosis. One died because of grade IV mucositis and overlapping infection. Conclusions: The treatment of recurrent NPC is controversial. Fractionated stereotactic radiotherapy is promising. However, the published trials are heterogeneous with respect to the selection criteria and treatment details. Prospective studies with long term follow-up data are warranted.

• Communications for Statistical Applications and Methods
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• 제21권4호
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• pp.285-296
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• 2014

The quantile residual life function has been effectively used to interpret results from the analysis of the proportional hazards model for censored survival data; however, the quantile residual life function is not always estimable with currently available semi-parametric regression methods in the presence of heavy censoring. A parametric regression approach may circumvent the difficulty of heavy censoring, but parametric assumptions on a baseline hazard function can cause a potential bias. This article proposes a Bayesian semi-parametric regression approach for inference on an unknown baseline hazard function while adjusting for available covariates. We consider a model-based approach but the proposed method does not suffer from strong parametric assumptions, enjoying a closed-form specification of the parametric regression approach without sacrificing the flexibility of the semi-parametric regression approach. The proposed method is applied to simulated data and heavily censored survival data to estimate various quantile residual lifetimes and adjust for important prognostic factors.

• 한국임상수의학회지
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• 제16권1호
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• pp.95-99
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• 1999

돼지 심장의 해부학적 구조에 대해서는 많은 연구가 보고되어 있으나 흉골 정중선 절개와 방정중선 절개 후 절개선에 나타나는 돼지 심장 대혈관들의 외과적 해부구조에 대한 보고는 아직 없고 심장적출 및 수술에 외과적 해부구조의 숙지가 필수적이므로, 체중 15kg - 25kg의 돼지 12마리를 4마리씩 3군, 즉 정중선절개군, 우측방정중선절개군, 좌측방정중선절개군으로 나누어 흉골열개 후 나타난 심장 대혈관들의 육안적 외과구조를 보고하고 심장적출술을 시도해 각 수술절개 접근법에 따른 수술의 용이성을 관찰하여 더 나은 수술접근법을 선택하는데 필요한 정보를 제공하고자 본 실험을 실시하였다. 그 결과, 우측과 좌측 방정중선절개법에 의해 흉골을 완전 열개시에는 제 1흉골과 갑상연골 부위에서 정중선으로 접근하는 초승달형 절개를 통해 internal mammary artery의 절개 위험성을 피할 수 있음을 발견하였고 흉골정중선절개에서는 상행대동맥의 정 중앙부에 aortic cannula를 쉽게 장착할 수 있었고 특히 비숙련자에게 더 적절한 수술 방법임을 알 수 있었다. 한편 숙련자가 심장적출이 아닌 동맥관개존증등과 같은 심장수술의 경우에는 방 정중선절개로써 환축의 수술 후 통증을 감소시키고 조기치유가 가능하다면, 초승달형 절개법을 응용한 방정중선 절개를 권할 수 있고 이에 따른 임상적 관찰이 요구되는 바이다.

• 한국안전학회지
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• 제32권5호
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• pp.129-134
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• 2017

This study aims to develop the traffic accident models by circular intersection type using count data model. The number of accident, the number of fatal and injured persons(FSI), and EPDO are calculated from the traffic accident data of TAAS. The circular intersection accident models are developed through Poisson and negative binomial regression analysis. The main results of this study are as follows. First, the null hypotheses that there are differences in the number of traffic accidents, FSI and EPDO by type of circular intersections are rejected. Second, the scale of intersection(median, large), number of approach road, mean width and length of exit road, area of the circulating roadway and central island are selected as factors influencing the number of traffic accidents, FSI and EPDO in rotary. Third, the scale of intersection(median), guide signs(limited speed, direction, roundabout), number of approach road, entry angle, area of the intersection and central island are adopted as factors influencing the number of traffic accidents, FSI and EPDO in roundabout. Finally, transferring from rotary to roundabout could be expected to make the accident decrease.

• Journal of Korean Neurosurgical Society
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• 제54권5호
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• pp.373-378
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• 2013

Objective : We present our experience of conventional posterior approach without fat lateral approach for ventral foramen magnum (FM) meningioma (FM meningioma) and tried to evaluate the approach is applicable to ventral FM meningioma. Methods : From January 1999 to March 2011, 11 patients with a ventral FM meningioma underwent a conventional posterior approach without further extension of lateral bony window. The tumor was removed through a working space between the dura and arachnoid membrane at the cervicomedullary junction with minimal retraction of medulla, spinal cord or cerebellum. Care should be taken not to violate arachnoid membrane. Results : Preoperatively, six patients were of Nurick grade 1, three were of grade 2, and two were of grade 3. Median follow-up period was 55 months (range, 20-163 months). The extent of resection was Simpson grade I in one case and Simpson grade II in remaining 10 cases. Clinical symptoms improved in eight patients and stable in three patients. There were no recurrences during the follow-up period. Postoperative morbidities included one pseudomeningocele and one transient dysphagia with dysarthria. Conclusion : Ventral FM meningiomas can be removed gross totally using a posterior approach without fat lateral approach. The arachnoid membrane can then be exploited as an anatomical barrier. However, this approach should be taken with a thorough understanding of its anatomical limitation.

• 한국콘텐츠학회논문지
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• 제6권4호
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• pp.11-18
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• 2006

본 논문에서는 두 가지 새로운 임펄스 잡음 검출기를 설계하고 총변량(total variation) 최적화를 통하여 영상에 존재하는 임펄스 잡음을 제거하는 방법을 제안한다. 설계된 임펄스 잡음 검출기는 적응 미디언 필터(AMF:Adaptive Median Filter)를 기반으로 하고 있으며 기존의 검출기에 비해 잡음검출의 정확도가 높고 영상의 디테일 정보를 잡음으로 오인하는 확률을 줄였다. 또한 제안하는 검출기는 잡음발생 확률에 무관하게 우수한 성능을 유지한다. 영상에서의 잡음제거는 제안된 검출기에 의해 얻어진 잡음후보 화소에 대해서만 총변량 최적화를 적용하므로 불필요한 계산을 줄이고 영상의 경계선을 잘 보존하면서 잡음을 제거할 수 있다. 실험결과 제안하는 2단 구조의 잡음제거 알고리즘은 다양한 형태의 잡음 밀도에 대해서 기존의 알고리즘에 비해 약 2dB 정도의 화질개선 효과를 얻었다.

• 기술사
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• 제21권4호
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• pp.19-32
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• 1988

Whereas is non-symmetrical distribution manufacturing process the traditional X-chart by Shewhart is not plotted relatively on the central line but plotted on the skew of upper-hand side or lower-hand side. That is to say, for the purpose of producing either upper-specification-oriented items or lower-specification-oriented items, and when we carry out tighter control so as to have them pass only its specifications, the distribution shape naturally has a non-normal distribution. In the Shewhart X-chart, which is the most widely used one in Korea, such skewed distributions make tile plots to be inclined below or above the central line or outside the control limits although no assignable causes can be found. To overcome such short comings is non-normally distributed processes, a distribution-free type of confidence interval can be used, which should be haled on order statistics. This thesis is concerned with the design of control chart based on a sample median which is easy to use in practical situation and therefore properties for non-normal distributions, such as Gamma, Beta, Lognormal, Weibull, Pareto, and Truncated-normal distributions, may be easily analyzed. To enhance this improvement, I proved the property of practical applications of control chart method by comparing and analyzing the case studies of practical application of special purpose control chart method, and also by introducing the new designed median control chart.

• 대한원격탐사학회지
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• 제33권1호
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• pp.89-95
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• 2017

Ship detection in synthetic aperture radar(SAR)imagery has long been an active research topic and has many applications. In this paper,we propose an efficient method for detecting ships from SAR imagery using filtering. This method exploits ship masking using a median filter that considers maximum ship sizes and detects ships from the reference image, to which a Non-Local means (NL-means) filter is applied for speckle de-noising and a differential image created from the difference between the reference image and the median filtered image. As the pixels of the ship in the SAR imagery have sufficiently higher values than the surrounding sea, the ship detection process is composed primarily of filtering based on this characteristic. The performance test for this method is validated using KOMPSAT-5 (Korea Multi-Purpose Satellite-5) SAR imagery. According to the accuracy assessment, the overall accuracy of the region that does not include land is 76.79%, and user accuracy is 71.31%. It is demonstrated that the proposed detection method is suitable to detect ships in SAR imagery and enables us to detect ships more easily and efficiently.

• 소음진동
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• 제10권5호
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• pp.769-774
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• 2000

The purpose of the work is to present successful applications of a modified wavelet shrinkage method for the accurate and fast estimation of a transfer function. Although the experimental process of determining a transfer function introduces not only Gaussian but also non-Gaussian noises, most existing estimation methods are based only on a Gaussian noise model. To overcome this limitation, we propose to employ a modified wavelet shrinkage method in which L1 -based median filtering and L2 -based wavelet shrinkage are applied repeatedly. The underlying theory behind this approach is briefly explained and the superior performance of this modified wavelet shrinkage technique is demonstrated by a numerical example.

• 대한산업공학회지
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• 제19권4호
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• pp.87-96
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• 1993

Spectrum analysis of surface electromyogram (FMG) signals is an effective approach to the study of localized muscular fatigue during isometric contraction. Many investigators have con firmed the frequency of the EMG signals being lowered during sustained contaction. In this study, the cyclic loading tasks were performed, and a comparison was made for the median power frequency shift pattern of the EMG signals with the sustained contraction of the same load. The median power frequency shift of the EMG signals for the cyclic loading task was found to be a part of that for the sustained contraction. Based on this result, a new muscle fatigue index was computed by normalizing the duration of the sustained contraction. A fatigue index was obtained as a function of exertion level and the work/rest schedule. With the proposed fatigue index, it is possible to evaluate or predict the degree of muscular fatigue for a physically demanding task.