• 한국항공우주학회지
• /
• 제32권10호
• /
• pp.46-52
• /
• 2004

본 논문은 2중으로 다중화된 무인 비행체의 다중화 관리 설계 방법에 대하여 논의한다. CCM(Cross Channel Monitor) 기법의 두 주요 인자, 즉 두 채널간의 편차 허용한도인 문 턱값(threshold) 및 지속시간(persistence count)을 어떻게 설계하여야 하는 가에 관한 문제를 통계학적인 해석을 사용하여 그 해결법을 제시하였다. 또한, 무인 비행체의 생존확률을 증대시킬 수 있는 해석적 다중화 가법에 대한 문제를 칼만 필터링 (Kalman filtering)을 적용하여 접근하였다. 여기서 제시된 방법으로 설계된 CCM 및 칼만 필터링을 이용한 해석적 다중화의 설계 결과들은 XV-15 틸트 로터 비행체에 적용되어, 그 설계의 타당성이 시뮬레이션을 통하여 검증되었다.

• Clinical and Experimental Pediatrics
• /
• 제62권4호
• /
• pp.138-143
• /
• 2019

Purpose: Prognostic factors of coronary aneurysms in Kawasaki disease have been investigated in many studies. The aim of this study was to identify risk factors associated with early and late coronary artery outcomes in treated patients with Kawasaki disease. Methods: A total of 392 patients diagnosed with Kawasaki disease from January 2012 to December 2015 in Pusan National University Children's Hospital were retrospectively selected as subjects of the present study to determine risk factors for coronary aneurysms and persistence of coronary aneurysms after a 1-year follow-up. Results: Coronary aneurysms were detected in 30 of 392 patients within 1 month after the occurrence of Kawasaki disease. Coronary aneurysms persisted in 5 of 30 patients after a 1-year follow-up. A long duration of fever (adjusted odds ratio [OR], 1.47; 95% confidence interval [CI], 1.06-2.02; P=0.018) and high platelet count (adjusted OR, 1.00; 95% CI, 1.00-1.01; P=0.009) were found to be independent factors to predict the development of coronary aneurysms in the early phase. Initial coronary severity (adjusted OR, 46.0; 95% CI, 2.01-1047.80; P=0.016) and a high white blood cell count (adjusted OR, 1.17; 95% CI, 1.01-1.36; P=0.028) were found to be significant factors for the persistence of late coronary aneurysms in univariate analysis. However, no significant factors were found in multivariate analysis. Conclusion: These data are from early and late follow-up of coronary aneurysms in our unit. Further studies are needed to determine the mechanisms involved in the disappearance of coronary aneurysms and related factors.

• Communications for Statistical Applications and Methods
• /
• 제25권1호
• /
• pp.29-42
• /
• 2018

We combine the integer-valued GARCH(1, 1) model with a generalized regime-switching model to propose a dynamic count time series model. Our model adopts Markov-chains with time-varying dependent transition probabilities to model dynamic count time series called the generalized regime-switching integer-valued GARCH(1, 1) (GRS-INGARCH(1, 1)) models. We derive a recursive formula of the conditional probability of the regime in the Markov-chain given the past information, in terms of transition probabilities of the Markov-chain and the Poisson parameters of the INGARCH(1, 1) process. In addition, we also study the forecasting of the Poisson parameter as well as the cumulative impulse response function of the model, which is a measure for the persistence of volatility. A Monte-Carlo simulation is conducted to see the performances of volatility forecasting and behaviors of cumulative impulse response coefficients as well as conditional maximum likelihood estimation; consequently, a real data application is given.

• Clinical and Experimental Pediatrics
• /
• 제52권6호
• /
• pp.633-642
• /
• 2009

Neutropenia is defined as an absolute neutrophil count (ANC) of <$1,500/{\mu}L$, and the severity of neutropenia generally can be graded as mild ($1,000-1,500/{\mu}L$), moderate ($500-1,000/{\mu}L$), or severe (<500/$\mu{L}$). This stratification aids in predicting the risk of pyogenic infection because the susceptibility to life-threatening infections is significantly increased in patients with prolonged episodes of severe neutropenia. Especially cancer-related neutropenia carry significant mortality. Neutropenia can develop under various conditions such as decreased bone marrow production, the sequestering of neutrophils, and increased destruction of neutrophils in the peripheral blood. Neutropenia is classified according to the etiology as congenital or acquired, with the latter further defined according to the etiology or pathology. The clinical result is increased risk for infection, which is directly proportional to the severity and duration of the neutropenia. The typical workup of neutropenia starts with a 6-week period in which complete blood counts are measured twice weekly to document the persistence of the neutropenia and whether a cyclic pattern is present. When persistent neutropenia is diagnosed and no spontaneous recovery occurs within 3 months, a more extensive evaluation is advised. Treatment is usually unnecessary for most patients with severe neutropenia, as the majority of patients have a good prognosis. However, for patients who have severe and frequent infections, treatment with filgrastim may prevent infectious complications and improve quality of life.

• International Journal of Control, Automation, and Systems
• /
• 제5권1호
• /
• pp.104-109
• /
• 2007

This paper is about a redundancy management system design for the Smart UAV(unmanned aerial vehicle) which utilizes the tilt..rotor mechanism. In order to meet the safety requirement on the PLOC(probability of loss of control) of $1.7{\times}10^{-5}$ per flight hour for FCS (flight control system) failures, a digital FCS is mechanized with a dual redundant structure. A fault detection system which is composed of a CCM(cross channel monitor) and analytic redundancy using the Kalman filtering is designed, and its effectiveness is evaluated through experiments. A threshold level and persistence count for managing redundant sensors are designed based on the statistical analysis of the FCS sensors. To increase the survivability of the UAV after the loss of critical sensors in the SAS(stability augmentation system) and to provide reference information for a tie-breaking condition at which an ILM(in-line monitor) cannot distinguish the faulty channel between two operating ones, the Kalman filter approach is investigated.

• 대한수의학회지
• /
• 제51권1호
• /
• pp.21-28
• /
• 2011

Salmonella Enteritidis (SE) has been a major causative agent of food-borne human disease due to consumption of contaminated eggs and poultry meat. To prevent SE infection in poultry, and therefore minimize human infections, vaccination with either killed or live SE vaccine is suggested. We evaluated a newly developed killed bacterin using a representative SE isolate in Korea. Among pool of SE isolates, two highly virulent isolates (the one isolate from chicken, the other from human) were selected by measuring mortality in mouse and chickens administered. The chickens were injected intramuscularly with killed vaccine and were challenged with highly virulent SE strain 3 week after vaccination. The recovered colony count (cfu/g) of spleen and cecal content in the vaccinated groups was reduced compared with those of the unvaccinated control group. The antibody level in the vaccinated groups was higher at 3 week post vaccination. These results indicate that vaccination with killed vaccine was effective in preventing the infection of virulent SE. Further study for a large number of layers should be needed for the effect of egg production, SE shedding in feces, persistence of antibody level.

• Clinical and Experimental Pediatrics
• /
• 제64권5호
• /
• pp.229-238
• /
• 2021

Background: Bronchial hyperresponsiveness (BHR), an important physiological feature of asthma, is a prognostic marker of childhood asthma. Purpose: We aimed to investigate the factors associated with BHR in adolescents with childhood asthma. Methods: Two hundred and fifteen adolescents (≥13 years of age; 149 males, 66 females) who were diagnosed with asthma during childhood were enrolled, underwent methacholine challenge tests, and were divided into the BHR group (<25 mg/mL of provocation concentration causing a 20% fall in forced expiratory volume in 1 second [FEV₁] [PC₂₀], n=113) or non-BHR group (≥25 mg/mL of PC₂₀, n=102). We examined longitudinal changes in BHR and the risk factors for its persistence in the 108 adolescents for whom baseline data, including methacholine PC₂₀ at age 6 years, were available. Multivariate logistic regression analyses were performed to assess the factors associated with BHR in adolescents. Results: Mold sensitization (adjusted odds ratio [aOR], 5.569; P=0.005) and increased blood eosinophil count (aOR, 1.002; P=0.026) were independently associated with BHR in boys but not girls. The odds of BHR decreased by 32% with each 1-year increase in age in boys (aOR, 0.683; P=0.010) but not girls. A reduced FEV₁/forced vital capacity ratio (<90%) was independently related with BHR in female patients only (aOR, 7.500; P=0.007). BHR decreased with age throughout childhood. A low methacholine PC₂₀ at age 6 years was independently associated with persistent BHR throughout childhood in male and female patients, whereas early mold sensitization was a risk factor for persistent BHR in male patients only (aOR, 7.718; P=0.028). Conclusion: Our study revealed sex-specific differences in the factors associated with BHR in adolescents with childhood asthma. Our findings suggest the risk factors that might affect asthma transition from childhood to adolescence and adulthood.

• 인지과학
• /
• 제2권2호
• /
• pp.405-428
• /
• 1990

언어는 정보교환이라는 사회적 기능을 가지고 있다. 60년대 이래로 언어학자들의 관심이 언어의 정보전달 기능, 즉 어떠한 의미가 어떤 형식을 통하여 어떻게 전달되는가 하는, 의미, 형식, 기능의 관계에 점차 집중되게 되었다. 이러한 관계는 문장분석보다는 담화분석을 통하여 더욱 명백하게 파악된다. 본 연구는 한국 설화문에서 사용되는 화제표현의 방법과 표현된 화제의 연속성을 측정함으로 효율적인 정보교환의 방법을 살펴보았다. 분석된 문법구조들은 영대용, 인칭대명사, 지시대명사, 고유대명사, 지시사 뒤에 오는 명사, 소유격을 따르는 명사, 한정적 명사 그리고 비한정적 명사, 모두 8가지이다. 본 연구의 결과를 다음과 같이 요약할수 있다. 첫째, 한국 설화문에서 '인간임'(humanness)이 가장 강한 화제의 연속성을 나타낸다. 인간지시 논항들은 주로 행위자 또는 경엄자를 나타내기 때문에 절이난 담화의 화제역학을 한다. 둘째, 이들 문법구조들은 각기 다른 화제표현의 연속성 정도를 나타낸다. 연속성 정도가 높은 구조일수록 표현이 간단하며, 연속성의 정도가 낮을수록 표현이 복잡하다. 셋째, 화제표현의 연속성은 구조들의 통사적 특성 이외에 사회적문화적 요인들과 작가의 화용상의 목적 등에 좌우되기도 한다. 마지막으로, 실질적인 정보교환의 방법을 파악하기 위하여, 구어체와 문어체 담화문을 비교분석하여 화제표현의 효율적 방법을 고찰할 것을 제의한다.