• Communications for Statistical Applications and Methods
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• 제9권1호
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• pp.129-139
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• 2002

Default Bayesian method for detecting the changes in sequences of independent exponential random variates and independent Poisson random variates is considered. Noninformative priors are assumed for all the parameters in both of change models. Default Bayes factors, AIBF, MIBF, FBF, to check whether there is any change or not on each sequence and the posterior probability densities of change at each time point are derived. Theoretical results discussed in this paper are applied to some numerical data.

• Journal of Advanced Marine Engineering and Technology
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• 제40권1호
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• pp.62-68
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• 2016

실내 위치인식 기술 중 하나인 WiFi Fingerprint는 기존의 WiFi access point(AP)의 거리에 따른 신호 세기를 활용하여 위치를 추정하는 편리함 때문에 많은 연구가 이루어지고 있다. 하지만 이 방식은 Radio map에 저장된 Reference point에 의존하기 때문에 다른 방식에 비해 위치의 분해능이 떨어지고 연산량이 많다. 본 논문에서는 이러한 문제를 해결하기 위하여 WiFi와 BLE를 융합한 Log-Distance Path Loss Model 기반의 Radio map 설계 알고리즘을 제안한다. 제안한 알고리즘은 Log-Distance Path Loss Model이 적용된 변수 값을 추출하여 Radio map을 설계하는 방식이며 Median Filter를 적용하여 오차를 개선하였다. 기존 Fingerprint와 비교하여 실험한 결과, 위치의 정확도는 평균 2.747m에서 2.112m로 0.635m 감소되는 것을 확인하였으며 연산량은 AP 환경에 따라 33%이상 감소하는 것을 확인하였다.

• 대한임상전기생리학회지
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• 제5권2호
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• pp.11-21
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• 2007

The purpose of this study were to investigate influence of heat stress temperature on sympathetic nerve activities. Subjects were 8 normal adults (4 men, 4 women, 21.36 years old). First sympathetic nerve activities were measured at the point that increase of core temperature stops at the state of applying normal thermic temperature (NIT; $34^{\circ}C$). After measurement, temperature of bathtub was increased to heat stress temperature (HST; $46^{\circ}C$) and sympathetic nerve activities were remeasured at the point that temperature increase stops. Sympathetic skin response (SSR) were analyzed using EMG, IR thermometer, and auto stethoscope. SSR latency showed significant differences at both palms by electrical stimulation to median nerve (p<.05). Electrical stimulation to forehead showed significant difference at left palm (p<.05) and electrical stimulation to navel showed significant difference at right palm (p<.05). Median nerve in changes of SSR amplitude showed significant differences at both palms in HST (p<.01). Electrical stimulation to navel showed significant difference at left palm (p<.05). Ts of forehead and xiphoid process showed significant differences (p<0.01). Tc of oral (p<0.05) and inner ear (p<0.01) showed significant differences. Pulse rate showed significant difference (<0.05). This study showed that immersion in HST had significant decrease of excitability in sympathetic nervous system compared to immersion in NTT.

• Clinical and Experimental Pediatrics
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• 제60권2호
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• pp.45-49
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• 2017

Purpose: Serum level of 25-hydroxyvitamin D (25-OHD) is considered as the most appropriate marker of vitamin D status. However, only a few studies have investigated the relationship between 25-OHD and parathyroid hormone (PTH) in children. To this end, this study was aimed at evaluating the lowest 25-OHD level that suppresses the production of parathyroid hormone in children. Methods: A retrospective record review was performed for children aged 0.2 to 18 years (n=193; 106 boys and 87 girls) who underwent simultaneous measurements of serum 25-OHD and PTH levels between January 2010 and June 2014. Results: The inflection point of serum 25-OHD level for maximal suppression of PTH was at 18.0 ng/mL (95% confidence interval, 14.3-21.7 ng/mL). The median PTH level of the children with 25-OHD levels of <18.0 ng/mL was higher than that of children with 25-OHD levels ${\geq}$ 18.0 ng/mL (P<0.0001). The median calcium level of children with 25-OHD levels<18.0 ng/mL was lower than that of children with 25-OHD levels${\geq}18.0ng/mL$ (P=0.0001). The frequency of hyperparathyroidism was higher in the children with 25-OHD levels<18.0 ng/mL than in the children with 25-OHD levels${\geq}18.0ng/mL$ (P<0.0001). Hypocalcemia was more prevalent in the children with 25-OHD levels<18.0 ng/mL than in the children with 25-OHD levels${\geq}18.0ng/mL$ (P<0.0001). Conclusion: These data suggest that a vitamin D level of 18.0 ng/mL could be the criterion for 25-OHD deficiency in children at the inflection point of the maximal suppression of PTH.

• Radiation Oncology Journal
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• 제13권4호
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• pp.359-368
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• 1995

목적 : 자궁경부암환자에서 근치적 목적으로 방사선치료를 외부조사와 강내조사를 시행한 환자의 실패양상과 생존율을 관찰하고 예후인자를 분석하기 위하여 본 연구를 시도하였다. 방법 : 1982년 3월 부터 1990년 5월 까지 8년간 자궁경부암으로 진단받고 이대부속병원 치료방사선과에서 방사선치료를 시행한 환자 280예 중 근치목적의 방사선치료로서 외부조사와 강내조사를 완료한 환자 114예를 대상으로 후향적 분석을 하였다. 연령분포는 30세에서 77세 까지로 중앙값은 53세이었다. FIGO에 의한 병기분포는 IB 19예($16.7{\%}$), IIA 23예($20.2{\%}$), IIB 42예($36.8{\%}$), IIIA 12예($10.5{\%}$), IIIB 18예($15.8{\%}$)이었다. 병리조직학적소견은 112예가 편평상피암이었고 2예는 선암이었다. 방사선치료방법으로 외부조사는 6MV 선형가속기(6MV,NEC 1000X)를 사용하여 전 골반강에 40-54 Gy를 조사하였으며, 강내조사는 Cs-137 밀봉선원으로 Fletcher-Suit applicator를 사용하여 1회 내지 2회 시행하여 point A에 40-42 Gy를 조사하여 point A의 총 방사선 선량은 병기 IB-IIA는 80-90 Gy(중앙값: 8580 cGy)로, IIB이상은 85-100 Gy(중앙값: 8850 cGy)로 하였다. 추적기간은 1개월에서 85개월로서 중앙값은 30개월이었다. 결과 : 국소실패만 보인 경우는 20예로 전체환자의 $17.5{\%}$이었으며 원격전이와 동반한 국소실패를 보인 경우는 7예($6.1{\%}$)로 전체 국소실패율은 $23.7{\%}$(27/114)이었다. 병기에 따른 국소실패율은 IB에서 $10.5{\%}$, IIA에서 $8.7{\%}$, IIB에서 $23.8{\%}$, IIIA에서 $50.5{\%}$, IIIB에서 $38.9{\%}$이었다. 국소실패부위는 자궁경부가 가장 많아서 전체 국소실패의 $37.5{\%}$(12/32)를 차지하였으며 다음은 자궁막조직으로 $34.3{\%}$(11/32)이었다. 원격전이만 있는 보인 경우는 6예로 전체환자의 $5.3{\%}$를 차지하였다. 원격전이된 부위는 골에 가장 많았으며(4/14), 다음으로 쇄골상관절종(3/14), 간(2/14)의 순으로 나타났다. 재발시기는 치료완료후 3개월에서 50개월이며 중앙값은 15개월이었다. 합병증으로 직장손상이 5예, 방광손상이 9예로서 총 14예($12.3{\%}$)이었다. 전체환자의 5년 생존율은 $70.5{\%}$이었고 병기 IB는 $100{\%}$, IIA는 $76.9{\%}$, IIB는 $77.6{\%}$, IIIA는 $87.5{\%}$, IIIB는 $69.1{\%}$이었다. 5년 무병생존율은 전체환자에서 $53.6{\%}$이었으며, 병기 IB는 $81.3{\%}$, IIA는 $67.9{\%}$, IIB는 $46.8{\%}$, IIIA는 $45.4{\%}$, IIIB는 $34.4{\%}$를 보였다. 무병생존율에 관계되는 예후인자는 다변수 분석에 의하면 performance status(P=0.0063)와 치료반응율(P=0.0026)은 유의성이 있었으나 병기,나이 및 point A의 방사선 선량은 유의성이 없었다. 결론: 자궁경부암환자에서 방사선치료 단독요법에 의한 치료성적은 병기 IB와 IIA는 양호하였으나 IIB이상에서 Point A의 방사선 선량을 90 Gy이상 증가시켜도 국소실패율이 높고 생존율의 향상을 얻을 수 없기 때문에 항암제 혹은 방사선감작제와 병용함으로써 국소제어율을 높이고 원격전이를 감소시키는 방법이 앞으로 연구되어져야 할 과제라고 생각된다.

• Asian Pacific Journal of Cancer Prevention
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• 제15권4호
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• pp.1667-1670
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• 2014

Background: Calprotectin in feces seems to be a more sensitive marker for gastrointestinal (GI) cancers than fecal occult blood, but its specificity may be too low for screening average risk populations. This study aims at evaluating the diagnostic value of fecal calprotectin as a screening biomarker for GI malignancies. Materials and Methods: In a case-control study, 100 patients with GI malignancies (50 patients with colorectal cancer and 50 patients with gastric cancer) and 50 controls were recruited in Tabriz Imam Reza and Sina hospitals during a 24-month period. One to two weeks after the last endoscopy/colonoscopy, fecal specimens were collected by the patients and examined by ELISA method for quantitative measurement of calprotectin content. The results were compared between the three groups. Results: The mean fecal calprotectin level was $109.1{\pm}105.3$ (2.3-454.3, median:74), $241.1{\pm}205.2$ (3.4-610.0, median:19.3) and $45.9{\pm}55.1{\mu}g/g$ (1.3-257.1, median:19.3) in gastric cancer, colorectal cancer and control group, respectively, the differences being significant (p<0.001) and remaining after adjustment for age. The optimal cut-off point for fecal calprotectin was ${\geq}75.8{\mu}g/g$ for distinguishing colorectal cancer from normal cases (sensitivity and specificity of 80% and 84%, respectively). This value was ${\geq}41.9{\mu}g/g$ for distinguishing gastric cancer from normal cases (sensitivity and specificity of 62%). Conclusions: Our results revealed that fecal calprotectin might be a useful and non-invasive biomarker for distinguishing colorectal cancer from non-malignant GI conditions. However, due to low sensitivity and specificity, this biomarker may not help physicians distinguishing gastric cancer cases from healthy subjects.

• Asian Pacific Journal of Cancer Prevention
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• 제15권20호
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• pp.8987-8992
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• 2014

Background: The efficacy of concurrent chemoradiotherapy in the treatment of locally advanced cervical cancer is well established. We aimed to investigate the long-term efficacy of definitive concurrent chemoradiotherapy for cervical cancer in the University of Malaya Medical Centre. Materials and Methods: A cohort of 60 patients with FIGO stage IB2-IVA cervical cancer who were treated with definitive concurrent chemoradiotherapy with cisplatin followed by intracavitary brachytherapy or external beam radiotherapy (EBRT) boost between November 2001 and May 2008 were analysed. Patients were initially treated with weekly intravenous cisplatin ($40mg/m^2$) concurrent with daily EBRT to pelvis of 45-50Gy followed by low dose rate brachytherapy or EBRT boost to tumour. Local control rate, progression free survival, overall survival and treatment related toxicities graded by the RTOG criteria were evaluated. Results: The mean age was 56. At the median follow-up of 72 months, the estimated 5-year progression-free survival (PFS) (median PFS 39 months) and the 5-year overall survival (OS) (median OS 51 months) were 48% and 50% respectively. The 5-year local control rate was 67.3%. Grade 3-4 late gastrointestinal and genitourinary toxicity occurred in 9.3% of patients. Conclusions: The 5-year PFS and the 5-year OS in this cohort were lower than in other institutions. More advanced stage at presentation, longer overall treatment time (OTT) of more than fifty-six days and lower total dose to point A were the potential factors contributing to a lower survival.

• 한국정보통신학회논문지
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• 제16권3호
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• pp.585-590
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• 2012

관상동맥 중재술은 관상동맥 조영술과 동시에 치료를 시행하는 방법으로 심도관 검사의 핵심으로 자리잡았다. 관상동맥중재술 시에는 혈관의 협착지점에 스텐트를 삽입하여야 하기 때문에 혈관의 손상이나 파열에 주의하여야 한다. 이에 시술자는 혈관의 손상이나 파열의 문제를 해결하기 위해 혈관의 경로를 정확하게 인식하여야 한다. 하지만 영상의 화질에 따른 문제들로 인하여 혈관의 경로추출에 오류를 범할 수 있다. 따라서 본 논문에서는 영상의 화질에 영향을 미치는 영상잡음에 대한 성능평가를 위하여 전처리 과정으로 미디언 필터링을 실시하였고 비교 실험을 위해 소벨 에지 추출 기법을 이용하여 퍼지 에지 추출 기법의 성능을 실험하였다. 그 결과 미디언 필터링을 적용한 퍼지 에지추출 기법의 영상이 잡음 제거와 신호의 검출 성능이 우수하게 나타났다.

• Korean Journal of Radiology
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• 제21권5호
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• pp.561-571
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• 2020

Objective: To evaluate the clinical utility of ultrafast dynamic contrast-enhanced (DCE)-MRI compared to conventional DCE-MRI by studying lesion conspicuity and size according to the level of background parenchymal enhancement (BPE). Materials and Methods: This study included 360 women (median age, 54 years; range, 26-82 years) with 361 who had undergone breast MRI, including both ultrafast and conventional DCE-MRI before surgery, between January and December 2017. Conspicuity was evaluated using a five-point score. Size was measured as the single maximal diameter. The Wilcoxon signed-rank test was used to compare median conspicuity score. To identify factors associated with conspicuity, multivariable logistic regression was performed. Absolute agreement between size at MRI and histopathologic examination was assessed using the intraclass correlation coefficient (ICC). Results: The median conspicuity scores were 5 at both scans, but the interquartile ranges were significantly different (5-5 at ultrafast vs. 4-5 at conventional, p < 0.001). Premenopausal status (odds ratio [OR] = 2.2, p = 0.048), non-mass enhancement (OR = 4.1, p = 0.001), moderate to marked BPE (OR = 7.5, p < 0.001), and shorter time to enhancement (OR = 0.9, p = 0.043) were independently associated with better conspicuity at ultrafast scans. Tumor size agreement between MRI and histopathologic examination was similar for both scans (ICC = 0.66 for ultrafast vs. 0.63 for conventional). Conclusion: Ultrafast DCE-MRI could improve lesion conspicuity compared to conventional DCE-MRI, especially in women with premenopausal status, non-mass enhancement, moderate to marked BPE or short time to enhancement.

• 제어로봇시스템학회논문지
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• 제16권5호
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• pp.440-445
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• 2010

This paper proposes a single accelerometer sensor control algorithm to mobile inverted pendulum, generally called 'Segway', and evaluates the performance of this system comparing to the conventional ones. The commercialized 'Prototype Segway-PT' is initially considered as a next-generation transport vehicle. However, this robot is operated by three gyroscopes and two accelerometers to control the posture and speed, and it requires the complex signal processing for fusing the two sets of data. As the result of this, the growth rate of market size of 'Segway' is slow because of its high price mainly. In this paper, the mobile inverted pendulum is operated by a single accelerometer to simplify the control system to lower the price. Low pass filter is one of the good sensors to reducing the variation of an accelerometer, but it has time delay. This time delay disturbs real-time mobile inverted pendulum control. Like this, other various algorithms are used for this system, but each one has its own weak point. So this paper proposes a new filtering method, median filter and EKF. Median filter is used to image processing to reject impulse elements like salt and pepper noise. As the major performance evaluation parameter for the accelerometer, the high-frequency to low frequency ratio from FFT (Fast Fourier Transform) is used. Effectiveness of the proposed algorithms has been verified through the real experiments and the results are demonstrated.