• 한국통신학회논문지
• /
• 제35권4C호
• /
• pp.377-385
• /
• 2010

본 논문에서는 요구되어진 차단주파수를 갖는 MAXFLAT FIR필터 설계를 위하여 일반적이고 뚜렷한 방식을 제안하였다. 제안된 기술은 요구된 차단주파수를 갖는 필터계수를 계산에 의해 직접 구할 수 있는 임의의 차단주파수를 갖는 임펄스응답의 일반 공식과 필터의 평탄 차수를 결정하기 위하여 논리적으로도 분명한 공식을 제공한다. 또한 실험 결과 제안된 기술이 요구된 차단주파수를 갖는 MAXFLAT(maximally flat) FIR 필터 설계에 있어서 계산적으로 효율적이고 정확한 방식이라는 것이 입증되었다.

• 응용통계연구
• /
• 제20권3호
• /
• pp.515-530
• /
• 2007

진단검사에서 민감도와 특이도가 선택편향에 영향을 받을 때, 진단검사의 각층에서의 민감도와 1-특이도의 비로 얻어지는 층화우도비도 편의가 존재하게 된다. 따라서 편의가 있는 층화우도비로 찾아진 최적절사점도 잘못된 값이 된다. 본 연구에서는 Begg과 Greenes (1983)에 의해 제안된 수정 민감도와 특이도를 층화우도비에 적용하여, 선택편향이 수정되는 최적절사점을 찾아보았다. 그리고 선택편향이 최적절사점에 미치는 영향을 선택편향 수정인자를 통해 설명하였다.

• Environmental Analysis Health and Toxicology
• /
• 제23권2호
• /
• pp.67-77
• /
• 2008

It has been observed that the linear relationship between the logarithm of bioconcentration factor (log BCF) of highly hydrophobic chemicals and their log $K_{ow}$ breaks when log $K_{ow}$ becomes greater than 6.0. Consequently, super hydrophobic chemicals were not thought to cause baseline toxicity as a single compound. Researchers often call this phenomenon as "hydrophobicity cutoff" meaning that bioconcentration or corresponding baseline toxicity has a certain cutoff at high log $K_{ow}$ value of hydrophobic organic pollutants. The underlying assumption is that the increased molecular size with increasing hydrophobicity prohibits highly hydrophobic compounds from crossing biological membranes. However, there are debates among scientists about mechanisms and at which log $K_{ow}$ this phenomenon occurs. This paper reviews three hypotheses to explain observed "cutoff": steric effects, kinetic or physiological limitations, and chemical activity cutoff. Although the critical molecular size that makes biological membranes not permeable to hydrophobic organic chemicals is uncertain, size effects in combination with kinetic limitation would explain observed non-linearity between log BCF and log $K_{ow}$. Chemical activity of hydrophobic chemicals generally decreases with increasing melting point at their aqueous solubility. Thus, there may be a chemical activity cutoff of baseline toxicity if there is a critical chemical activity over which baseline effects can be observed.

• 생물정신의학
• /
• 제12권1호
• /
• pp.20-31
• /
• 2005

Objectives:This study was designed to investigate the characteristics of personality changes and emotional distress using the Personality Assessment Inventory (PAI) in patients with traumatic brain injury(TBI), divided into mild (MTBI) and severe (STBI) groups according to the severity of injury. Methods:The subjects were consisted of 25 patients with MTBI, 25 patients with STBI, and 25 normal controls. They were interviewed with the PAI. The data were analyzed by ${\chi}^2$ test, analysis of variance and Tukey test. Results:The results were the followings. First, Negative Impression in validity scales was elevated above cutoff point(T score 70) in both MTBI and STBI groups. Second, the clinical scales of which scores elevated above the cutoff point were Somatic Complaints, Anxiety, Anxiety-Related Disorders, Depression, and Schizophrenia in the MTBI, and Somatic Complaints and Depression in the STBI. Third, the clinical subscales above the cutoff point were Conversion, Somatization, Health Concerns, Affective Anxiety, Physiological Anxiety, Traumatic Stress, Cognitive Depression, Affective Depression, Physiological Depression, Thought Disorder, and Affective Instability in the MTBI, and Health Concerns, Cognitive Depression, Affective Depression, and Physiological Depression in the STBI. Fourth, Suicide Ideation in treatment scales was the only scale above the cutoff point in the MTBI and the others of the treatment and interpersonal scales in the MTBI and all of these scales of the STBI were not elevated above the cutoff point. Fifth, the scales of which scores showed significant difference between the MTBI and the STBI were Somatic Complaints, Anxiety, Depression, and Suicide Ideation, the subscales were Conversion, Somatization, Health Concerns, Affective Anxiety, Physiological Anxiety, Physiological Depression, and Psychotic Experiences. Conclusion:These results suggest that the patients with MTBI had more somatic and anxiety symptoms, depressed mood, and suicidal ideation than the patients with STBI. These characteristics are generally consistent with clinical observation and findings from previous studies of the patients with TBI, and the PAI seems to be a beneficial adjunctive assessment tool for the evaluation of patients with traumatic brain injury.

• Asian Pacific Journal of Cancer Prevention
• /
• 제15권4호
• /
• pp.1655-1658
• /
• 2014

Objective: To find a more appropriate alternative to D-dimer cutoff value for the diagnosis of deep vein thrombosis (DVT) in cancer patients. Methods: A total of 711 cancer patients with symptoms suspicious of DVT were included in the study. D-dimer levels were assessed using ELISA. All patients were subjected to imaging procedures. Results: Among 711 patients with cancer, 466 (65.5%) were females and 245 (34.5%) were males, with an average age of $57.3{\pm}13.23$ years. The mean age in the DVT group was significantly higher than in the non-DVT group (P<0.05). The D-dimer levels of the DVT group were significantly higher than those of the non-DVT group (P<0.05). The incidence rate of DVT varied significantly according to cancer type (P<0.05). Increasing age and lung cancer were significantly correlated with D-dimer levels (P<0.05), and a one-year increase in age was associated with a 14.28 ng/ml increase in the D-dimer value. The optimal cutoff point for D-dimer was found to be 981 ng/ml, with a sensitivity of 86.4%, specificity of 79.4%, and accuracy of 82.6%. If the D-dimer cutoff point was set to 981ng/ml, the specificity would increase from 61.8% to 85.5% without loss of sensitivity in patients aged 40 years or younger. In patients aged more than 40 years, the new cutoff almost doubled the specificity with slightly reduced sensitivity. Conclusion: In cancer patients, a new cutoff value of 981 ng/ml effectively improved the exclusion of DVT, especially for patients aged more than 40 years.

• 한국멀티미디어학회논문지
• /
• 제12권1호
• /
• pp.107-121
• /
• 2009

대기전력(Standby power) 소모가 발생하는 첫 번째 요인은 전원에서 IC로 들어오면서 거쳐야하는 기동전압 때문이며 나머지 하나는 IC가 동작할 때의 전류 때문이다. 본 논문에서는 대기전력 상태와 차단 시점의 패턴분석을 통해서 자동 On/Off할 수 있도록 하는 간단한 모듈장치 구성과 알고리즘 적용에 목적을 두었다. 이를 위해서 전력 신호분석과 모델링에 근간을 두었으며 대기전력 절감을 위해서 On/Off 차단기준을 마련했다. On/Off 차단 시점을 찾기 위해서 $1^{st}$ SCS와 $2^{nd}$ SCS의 차분값(subtraction value), 그리고 콘센트로부터 유입된 초당 샘플링 계수에 대한 중간값(median value)을 중요한 파라미터로써 정의한 다음 대기전력 상태에서의 유사그룹 및 유력패턴 그룹 생성 알고리즘을 수행했다.

• Clinical and Experimental Pediatrics
• /
• 제62권7호
• /
• pp.257-258
• /
• 2019

• Clinical and Experimental Pediatrics
• /
• 제61권1호
• /
• pp.6-11
• /
• 2018

Purpose: Mid-upper-arm circumference (MUAC) is considered an alternative screening method for obesity. The aims of this investigation were to examine the ability of MUAC to correctly identify children with elevated body mass index (BMI) and to determine the best MUAC cutoff point for identification of children with high BMI. Methods: Anthropometric measurements (height, weight, and MUAC) from a cross-sectional sample of 7,921 Pakistani children aged 5-14 years were analyzed. Pearson correlation coefficients between MUAC and other anthropometric measurements were calculated. Receiver operating characteristic curve analysis was used to determine the optimal MUAC cutoff point for identifying children with high BMI. Results: Among 7,921 children, the mean (${\pm}$standard deviation) age, BMI, and MUAC were 10.00 (${\pm}2.86years$), 16.16 (${\pm}2.66kg/m^2$), and 17.73 (${\pm}2.59cm$), respectively. The MUAC had a strong positive correlation with BMI. The optimal MUAC cutoff points indicating elevated BMI in boys ranged from 16.76 to 22.73, while the corresponding values in girls ranged from 16.38 to 20.57. Conclusion: MUAC may be used as a simple indicator of overweight/obesity in children, with reasonable accuracy in clinical settings.

• 대한수학회논문집
• /
• 제20권4호
• /
• pp.813-826
• /
• 2005

Regarding all particles at a fixed site as a cluster, the size of the largest cluster under the zero range invariant measures is well studied by Jeon et al.[5] for the case of density one. Here, the density of the finite zero-range process is given by the ratio between the number m of particles and the number n of sites. In this paper, we study the lower density case, i.e., the case m = o(n). Especially, when m ~ $n^{\beta}$,0 < ${\beta}$ < 1, we show that there is an interesting cutoff point around $\beta$ = 1/2.

• Clinical and Experimental Pediatrics
• /
• 제46권8호
• /
• pp.758-762
• /
• 2003

목 적 : 저자들은 발열을 주소로 입원한 3세 이하의 소아에서 초기 총 백혈구 수, 적혈구 침강 속도, C-반응성 단백질 정량적 검사를 통해 민감도와 특이도가 최대치에 이르는 수치를 차단점으로 선택하여 세균성 감염의 고위험군을 예측하고 항생제 치료의 지표로 삼고자 연구를 하였다. 방 법 : 2001년 6월부터 2002년 6월까지 조선대학교병원 소아과에 발열을 주소로 입원치료 하였던 환아 중 진찰 소견에서 발열에 대한 원인을 발견할 수 없었던 1개월에서 36개월 사이의 71명을 대상으로 하여 후향적으로 조사하였다. 대상 환아들을 세균성 감염과 비세균성 감염으로 분류한 후 각각의 진단 기준의 양성 예측치와 우도비를 계산하고 민감도와 특이도가 최대치에 이르는 수치를 차단점(cut-off point)으로 선택하여 그 수치에서의 민감도와 특이도를 조사하였다. 결 과 : 대상 환아 총 71명(남아 44명, 여아 27명)이고, 평균 연령은 12.7개월이었다. 세균성 감염인 경우는 20례(28%)이었으며, 요로 감염 12례, 세균혈증 5례, 뇌막염 3례 순이었다. 감염균은 E.coli 6례, K.pneumoniae 3례, E. faecalis 3례, Streptococcus ganguinis 3례, Salmonella 2례, S.aureus 1례, Stenotrophomonas maltophilia 1례, Streptococcus constellatus 1례였다. 총 백혈구 수, 적혈구 침강 속도, C-반응성 단백질은 세균성 감염군과 비세균성 감염군간의 유의한 차이를 보였다(P=0.038, 0.009, 0.002). 양성예측치와 우도비는 총 백혈구 수는 20,000/mm^3$ 이상에서 75%, 7.65이었으며, 적혈구 침강 속도는 30-50 mm/hr에서 60%, 3.83이었다. C-반응성 단백질의 양성 예측치와 우도비는 3-6 mg/dL에서 63%, 4.25이었다. 민감도와 특이도가 최대치에 이르는 수치는 총 백혈구 수 $20,000/mm^3$, 적혈구 침강 속도 30 mm/hr, C-반응성 단백질 3.0 mg/dL이었으며, 이 값에서의 민감도는 각각 75%, 79%, 83%, 특이도는 75%, 68%, 77%이었다. 결 론 : 비특이적 소견을 보이는 3세 이하 발열 환아에서 차단점을 총 백혈구 수 20,000/mm^3$, 적혈구 침강 속도 30 mm/hr, C-반응성 단백질 3.0 mg/dL으로 적용할 때 세균성 감염에서 선택적 치료 방침을 세울 수 있게 되리라 생각된다.