• 제목/요약/키워드: logistic equation

검색결과 131건 처리시간 0.025초

In vitro와 in vivo에서의 온도에 따른 스쿠티카충 성장의 수리 모델 (The mathematical model of temperature dependent growth of Scuticociliate Miamiensis avidus in vitro and in vivo conditions)

  • 오춘영
    • 한국어병학회지
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    • 제26권2호
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    • pp.65-75
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    • 2013
  • 실험실에서 온도 별로 스쿠티카충을 배양한 데이터(Table 1)를 사용 스쿠티카충 개체군의 변화율(1.2)과 성장 방정식(1.3)을 in vitro 조건에서 구했다. 이 모델에서는 스쿠티카충의 증가모델 식은 로지스틱 증가함수로 두 가지 온도에서의 스쿠티카충의 증가율 매개변수를 구하였고, 기생충으로 인한 숙주인 넙치에 치명적일 수 있는 기생충의 임계밀도를 구하였다. 또 다른 데이터는 같은 온도에서 스쿠티카충 수를 다양하게 넙치의 복강에 주사하는 그룹과 동일한 스쿠티카충 수를 복강에 주사한 후 온도를 다르게 한 두 그룹의 스쿠티카충의 감염으로 폐사한 실험데이터(Table 2)에 근거하여 넙치의 감염에서 폐사가 되는 시스템 식(1.5)을 세웠다. 정리에서는 감염된 넙치와 폐사된 넙치의 미분방정식계는 감염넙치와 폐사 넙치와의 평형점을 찾고 그 평형점에 대한 안정성과 불안정성을 설명하였다. 각 온도에서의 매개변수를 사용하면 방정식 (1.6)은 시간에 대해 넙치의 누적 폐사량을 알 수 있는 방정식이다. 이 논문에서는 다양한 초기값 $P_0$값에 따른 넙치의 폐사를 중심으로 보았으므로 온도와 $P_0$가 동시에 넙치폐사에 어떠한 관계를 갖는 연구를 하기에는 제약을 갖고 있다. 이 연구의 제한점에서 언급했듯 실험을 여러 번 시행한 것이 아니기 때문에 단지 근사적인 값으로 이해를 해야 한다. 또한 넙치의 면역력을 알 수 있다면 기생충으로부터 저항력을 연구하는데 오차를 좀 더 줄인 근사치를 구할 수 있을 것을 기대할 수 있을 것이다.

계획된 행위 이론을 적용한 모유수유의지 및 행위의 예측요인 분석 (Prediction of Breastfeeding Intentions and Behaviors : An Application of the Theory of Planned Behavior)

  • 김혜숙;남은숙
    • 대한간호학회지
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    • 제27권4호
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    • pp.796-806
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    • 1997
  • The majority of studies on breastfeeding consists of descriptive correlational studies identifying the incidence and correlates of breastfeeding. The theory of planned behavior has been shown to yield great predictive power for behavioral goals over which individuals have only limited control such as improving school grades and weight loss. The purpose of this study was to test the "theory of planned behavior" in the prediction of breastfeeding of mothers who delivered vaginally, One hundred mothers who delivered vaginally in one general hospital in Seoul and one general hospital and three private hospitals in Taejeon participated in this study. The instruments used for data collection in this study were developed by the researchers following the guidelines suggested by Ajzen & Fishbein(1980) and Ajzen & Madden(1986). The instruments included measurement of attitude, subjective norm, perceived behavioral control and intention. The collected data were analyzed using descriptive statistics, Pearson product moment correlation, hierachical multiple regression and logistic regression. The results are as follows ; 1. Intention to breastfeed correlated significantly with attitude, subjective norm and perceived behavioral control. Both attitude and subjective norm did not make a significant contribution to the prediction of intention, but the addition of perceived behavioral control to the regression equation greatly improved the model's predictive power, increasing the R²from .05 to .52. 2. Intention to breastfeed alone had a significant predictive effect on actual breastfeeding, resulting in a regression coefficient of .16(X²=8 60, p<.01), but when perceived behavioral control was added to the equation, intention was not a significant predictive variable and only perceived behavioral control showed significant predictive power on actual breastfeeding, resulting in a regression coefficient of .12(X²=4.69, p<.05). In sum, breastfeeding behavior lent only partial support to the second version of the theory of planned behavior, and because perceived behavioral control had a strong effect on intention to breastfeed and actual breastfeeding, It would be desirable to develop nursing intervention programs which focus on strengthening the perceived behavioral control for the promotion of breastfeeding.

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Probability of Early Retirement Among Emergency Physicians

  • Shin, Jaemyeong;Kim, Yun Jeong;Kim, Jong Kun;Lee, Dong Eun;Moon, Sungbae;Choe, Jae Young;Lee, Won Kee;Lee, Hyung Min;Cho, Kwang Hyun
    • Journal of Preventive Medicine and Public Health
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    • 제51권3호
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    • pp.154-162
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    • 2018
  • Objectives: Early retirement occurs when one's job satisfaction suffers due to employment mismatch resulting from factors such as inadequate compensation. Medical doctors report high levels of job stress and burnout relative to other professionals. These levels are highest among emergency physicians (EPs), and despite general improvements in their working conditions, early retirement continues to become more common in this population. The purpose of this study was to identify the factors influencing EPs intention to retire early and to develop a probability equation for its prediction. Methods: A secondary analysis of data from the 2015 Korean Society of Emergency Physicians Survey was performed. The variables potentially influencing early retirement were organized into personal characteristics, extrinsic factors, and intrinsic factors. Logistic regression analysis was performed to identify risk factors and to develop a probability equation; these findings were then arranged in a nomogram. Results: Of the 377 survey respondents included in the analysis, 48.0% intended to retire early. Risk factors for early retirement included level of satisfaction with the specialty and its outlook, slanderous reviews, emergency room safety, health status, workload intensity, age, and hospital type. Intrinsic factors (i.e., slanderous reviews and satisfaction with the specialty and its outlook) had a stronger influence on early retirement than did extrinsic factors. Conclusions: To promote career longevity among EPs, it is vital to improve emergency room safety and workload intensity, to enhance medical professionalism through a stronger vision of emergency medicine, and to strengthen the patient-doctor relationship.

보라성게 (Anthocidaris crassispina)의 연령과 성장 (Age and Growth of the Purple Sea Urchin, Anthocidaris crassispina in Cheju Island)

  • 홍성완;정상철
    • 한국수산과학회지
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    • 제31권2호
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    • pp.302-308
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    • 1998
  • 1995년 8월부터 1996년 7월까지 제주도 남제주군 대포리 연안에서 채집한 보라성게의 연령형질 (생식판)로서 성장을 규명한 결과는 다음과 같다. 1. 생식판 (madreporite)에 나타나는 윤문은 2세에서 6세군까지 뚜렷하게 관찰되었다. 2. 각장 (test diameter : TD)과 생식판경 (radius : R)과의 관계식은 다음과 같았다. TD= 22.58R-6.01 (r=0.960) 3. 월별 연변성장율 ($MGR\;:\;(R-r_n)/(r_n-r_{n-1})$)조사에서 추정한 윤문형성시기는 3월에서 5월 사이였다. 4. 각장조성의 월별 성장 경향은 12월에서 이듬해 3월 사이가 주 성장기였고, 4월에서 6월 사이는 성장의 휴지기, 그 외의 기간은 아주 완만한 성장을 하였다. 5. Bertalanffy식이 Gompertz식과 Logistic식보다 잔차 평방합이 적었고, 그 성장식은 다음과 같았다. $$L_t=46.65 (1-e^{-0.283(t+9.210)})$$, $$W_t=44.90 (1-e^{-0.283(t+9.210)})^3$$

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회복기 재활환자의 재입원에 영향을 미치는 요인: 건강보험 청구자료를 이용하여 (Factors Influencing Readmission of Convalescent Rehabilitation Patients: Using Health Insurance Review and Assessment Service Claims Data)

  • 신요한;정형선
    • 보건행정학회지
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    • 제31권4호
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    • pp.451-461
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    • 2021
  • Background: Readmissions related to lack of quality care harm both patients and health insurance finances. If the factors affecting readmission are identified, the readmission can be managed by controlling those factors. This paper aims to identify factors that affect readmissions of convalescent rehabilitation patients. Methods: Health Insurance Review and Assessment Service claims data were used to identify readmissions of convalescent patients who were admitted in hospitals and long-term care hospitals nationwide in 2018. Based on prior research, the socio-demographics, clinical, medical institution, and staffing levels characteristics were included in the research model as independent variables. Readmissions for convalescent rehabilitation treatment within 30 days after discharge were analyzed using logistic regression and generalization estimation equation. Results: The average readmission rate of the study subjects was 24.4%, and the risk of readmission decreases as age, length of stay, and the number of patients per physical therapist increase. In the patient group, the risk of readmission is lower in the spinal cord injury group and the musculoskeletal system group than in the brain injury group. The risk of readmission increases as the severity of patients and the number of patients per rehabilitation medicine specialist increases. Besides, the readmission risk is higher in men than women and long-term care hospitals than hospitals. Conclusion: "Reducing the readmission rate" is consistent with the ultimate goal of the convalescent rehabilitation system. Thus, it is necessary to prepare a mechanism for policy management of readmission.

종별 의료기관 외래 경증질환 약제비 본인부담 차등정책 효과분석 (An Analysis of Effects of Differential Coinsurance Policy and Utilization of Outpatients Care by Types of Medical Institutions)

  • 박윤성;김진숙
    • 보건행정학회지
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    • 제27권2호
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    • pp.128-138
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    • 2017
  • Background: The purpose of this study is to analyze the effects of differential coinsurance policy on prescription drug coverage of outpatients by types of medical institutions. Methods: In this study, we used a sample cohort database of the National Health Insurance Service and frequency analysis and marginal logistic regression model using generalized estimating equation were used for statistical analysis. Results: The summary on the major research is followed. First, about 16% of patients who used only tertiary or general hospital due to 52 ambulatory care sensitive conditions before policy implementation moved to hospitals and clinics. However, about 57% of them still use tertiary or general hospital. Second, the factors influencing the utilization of hospitals and clinics after the implementation of the policy were gender, age, and income level. As a result, the policy is effective to reduce the medical use of outpatient mental patients in tertiary or general hospital, but the effect is not significant. Conclusion: Therefore, in order to achieve the purpose of the policy for establishing the health care delivery system, it is necessary to adjust the co-payment so as to feel the burden on the co-payment when the outpatient for 52 ambulatory care sensitive conditions is used at the tertiary or general hospital.

우리나라 동해안 북형 통발에 대한 물레고둥(Buccinum striatissimum)의 망목 선택성에 관한 연구 (Study on the mesh selectivity of a drum shaped pot for finely-striate buccinum (Buccinum striatissimum) in the eastern coastal waters of Korea)

  • 김성훈;정성재;박창두;김병관
    • 수산해양기술연구
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    • 제56권3호
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    • pp.193-201
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    • 2020
  • The mesh selectivity of a drum shaped pot for finely-striate buccinum (Buccinum striatissimum) was conducted a total of eight times with four different mesh sizes (22, 35, 50 and 60 mm) from May to September, 2019 in the eastern coastal waters of Korea. The size selectivity analysis was estimated by the SELECT method to express logistic selectivity curves. In the results, the catch of finely-striate buccinum was occupied about 90% in the total catch weight. The equation of the master curve of selectivity was estimated to s(R) = exp(-7.778R+9.983)/[1+exp(-7.778R+9.983)]. The relative shell height of 50% selection was 1.284 and the selection range (SR) was 0.282. The optimal mesh size for 50% selection on the minimum maturation size (75 mm, Shell height) was estimated more than 60 mm by the master selectivity curve.

동해 중부해역에 출현하는 말쥐치(Thamnaconus modestus) 암컷의 성숙과 산란 (Maturation and spawning of female black scraper, Thamnaconus modestus in the coastal waters off Middle East Sea, Korea)

  • 남기문;유준택;김재원;박종혁;백근욱
    • 수산해양기술연구
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    • 제54권1호
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    • pp.89-95
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    • 2018
  • The maturation and spawning of black scraper, Thamnaconus modestus were studied using samples collected monthly from March, 2015 to February, 2016 in the coastal waters off Middle East Sea, Korea. The gonadosomatic index (GSI) of female was the highest in June. The spawning periods lasted from March to September based on histological observation of female gonad development. The percentage of sexually mature females estimated from a logistic function was over 50% for the size group 18.02 cm (total length, TL). The size of eggs spawned was between 0.40 to 0.58 mm. Fecundity varied between 185,648 and 9,747,250 eggs. The relationship between the fecundity and TL of the fish was expressed in the fecundity equation as $F=0.0297TL^{5.4835}$.

홈팀의 이점을 고려한 KBL 2006-2007 시즌 경기력 평가 (The Rating of Korean Basketball League Teams in 2006-2007 Season: Taking Account of Home-Court Advantage)

  • 이승천;변종석
    • Communications for Statistical Applications and Methods
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    • 제15권5호
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    • pp.687-695
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    • 2008
  • 홈/원정 방식으로 치러지는 스포츠 리그에서 일반적으로 홈팀의 승률이 50%가 넘는 현상에 대해 Courneya와 Carron (1992)은 홈팀의 이점(home advantage)이라는 용어로 설명하고 있다. 오늘날 스포츠 경기에서 홈팀의 이점은 자연스러운 현상으로 받아드려지고 있어 팀의 경기력 평가에서 중요한 요소의 하나로 인식되고 있다. 본 논문에서는 홈팀의 이점을 고려한 선형모형과 로지스틱 회귀모형을 이용하여 KBL 2006-2007 시즌에서 각 팀의 경기력을 평가하였다.

자기 회귀 웨이블릿 신경 회로망을 이용한 비선형 혼돈 시계열의 예측에 관한 연구 (A Study on the Prediction of the Nonlinear Chaotic Time Series Using a Self-Recurrent Wavelet Neural Network)

  • 이혜진;박진배;최윤호
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2004년도 하계학술대회 논문집 D
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    • pp.2209-2211
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    • 2004
  • Unlike the wavelet neural network, since a mother wavelet layer of the self-recurrent wavelet neural network (SRWNN) is composed of self-feedback neurons, it has the ability to store past information of the wavelet. Therefore we propose the prediction method for the nonlinear chaotic time series model using a SRWNN. The SRWNN model is learned for the modeling of a function such that the inputs arc known values of the time series and the output is the value in the future. The parameters of the network are tuned to minimize the difference between the nonlinear mapping of the chaotic time series and the output of SRWNN using the gradient-descent method for the adaptive backpropagation algorithm. Through the computer simulations, we demonstrate the feasibility and the effectiveness of our method for the prediction of the logistic map and the Mackey-Glass delay-differential equation as a nonlinear chaotic time series.

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