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Case Study on Measuring Technology Level Applying Growth Curve Model: Three Core Areas of Fishery Science and Technology (성장곡선 모형 적용을 통한 기술수준평가 사례 연구 : 특정 수산과학기술 분야를 중심으로)

  • Kim, Wan-Min;Park, Ju-Chan;Bark, Pyeng-Mu
    • The Journal of Fisheries Business Administration
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    • v.46 no.3
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    • pp.103-118
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    • 2015
  • The purpose of this paper is to discuss possibilities of applying growth curve models, such as Logistic, Log-Logistic, Log-Normal, Gompertz and Weibull, to three specific technology areas of Fishery Science and Technology in the process of measuring their technology level between Korea and countries with the state-of-the art level. Technology areas of hazard control of organism, environment restoration, and fish cluster detect were selected for this study. Expert panel survey was conducted to construct relevant panel data for years of 2013, 2016, and a future time of approaching the theoretical maximum technology level. The size of data was 70, 70 and 40 respectively. First finding is that estimation of shape and location parameters of each model was statistically significant, and lack-of-fit test using estimated parameters was statistically rejected for each model, meaning all models were good enough to apply for measuring technology levels. Second, three models other than Pearl and Gompertz seemed very appropriate to apply despite the fact that previous case studies have used only Gompertz and Pearl. This study suggests that Weibull model would be a very valid candidate for the purpose. Third, fish cluster detect technology level is relatively higher for both Korea and a country with the state-of-the-art among three areas as of 2013. However, all three areas seem to be approaching their limits(highest technology level point) until 2020 for countries with the state-of-the-art. This implies that Korea might have to speed up her research activities in order to catch up them prior to 2020. Final suggestion is that future study may better apply various and more appropriate models respectively considering each technology characteristics and other factors.

Related Factors of Depression according to Individual Attributes and Regional Environment: Using Multi-Level Analysis (다수준분석을 활용한 개인특성 및 지역환경에 따른 우울증 관련 영향요인 분석)

  • Moon, Seok-Jun;Lee, Ga Ram;Nam, Eun-Woo
    • Health Policy and Management
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    • v.30 no.3
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    • pp.355-365
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    • 2020
  • Background: This study is aimed to verify individual and regional-level factors affecting the depression of Koreans and to develop social programs for improving the depressive status. Methods: This study used individual-level variables from the Korean Community Health Survey (2018) and used the e-regional index of the Korean Statistical Information Service as the regional-level variable. A multi-level logistic regression was executed to identify individual and regional-level variables that were expected to affect the extent of depressive symptoms and to draw the receiver operating characteristic curve to compare the volume of impact between variables from both levels. Results: The results of the multi-level logistic regression analysis in regards to individual-level factors showed that older age, female gender, a lower income level, a lower education level, not having a spouse, the practice of walking, the consumption of breakfast higher levels of stress, and having high blood pressure or diabetes were associated with a greater increase in depressive symptoms. In terms of regional factors, areas with fewer cultural facilities and fewer car registration had higher levels of depressive symptoms. The comparison of area under the curve showed that individual factors had a greater influence than regional factors. Conclusion: This study showed that while both, individual and regional-level factors affect depression, the influence of the latter was relatively weaker as compared to the first. In this sense, it is necessary to develop programs focused on the individual, such as social prescribing at the local or community-level, rather than the city and nation-level approach that are currently prevalent.

Ecological Buffer Analysis of Western DMZ and Vicinity using Logistic Function Derived from TVI-Distance Curve (TVI-거리함수를 이용한 서부 DMZ 및 민통지역의 생태적 보전폭원 조사)

  • Kim, Sang-Wook
    • Journal of the Korean Association of Geographic Information Studies
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    • v.9 no.4
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    • pp.95-104
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    • 2006
  • The DMZ is a 248km long thin green line which has various landscapes of fields, hills and mountains. This study focused on western part of DMZ and vicinity which consist of abandoned rice paddy, wetlands and fields. The main purpose of this study is to detect the vegetation vitality from the western part of MDL to DMZ vicinity and identify and quantify ecological buffer(ecotone) width adopting logistic function derived from 'Vegetation Index-distance curve' using an Landsat ETM+ image acquired on June of 2002. Green leaf vegetation was quantified to identify the ecotone buffer in western DMZ and vicinity(civilian control area: CCA) using Transformed Vegetation Index(TVI) which is one of common measurement among various indices. Vegetation measurement from Military Demarcation Line(MDL) to vicinity area was investigated at 500m intervals to 10kms of southern and northern part of western DMZ and vicinity. The Logistic function models the sigmoid curve of growth with three stages of growth of initial competition and maturity. In the TVI-distance logistic curve, the maturity is high vegetation vitality, the competition is vitality changing, and the initial is low vitality. In the TVI-distance curve, maturity area of high TVI value is core area for ecological conservation, and the competition area between inflection points can be an ecotone(ecological buffer). In case of southern part, maximum TVI value is 221.92 and minimum is 207.16, and maximum TVI of northen part is 215.32 and minimum is 188.35. That means forest devastation of north Korean part of DMZ and vicinity is severer than that of south Korea. The width of core area for ecological conservation is 2,311m, and ecotone in the southern part is 5,339m, so minimum width from MDL for ecological conservation can be computed as 7,651m. In case of Northern part, the width of core area is 1,841m, and ecotone buffer is 5,014m, so ecological conservation width can be estimated as 6,855m. In case of northen part, width of estimated core area is less than that of DMZ width, which means ecological disturbance is very severe in northern part of western DMZ.

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The Study for Software Future Forecasting Failure Time Using Curve Regression Analysis (곡선 회귀모형을 이용한 소프트웨어 미래 고장 시간 예측에 관한 연구)

  • Kim, Hee-Cheul;Shin, Hyun-Cheul
    • Convergence Security Journal
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    • v.12 no.3
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    • pp.115-121
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    • 2012
  • Software failure time presented in the literature exhibit either constant, monotonic increasing or monotonic decreasing. For data analysis of software reliability model, data scale tools of trend analysis are developed. The methods of trend analysis are arithmetic mean test and Laplace trend test. Trend analysis only offers information of outline content. In this paper, we discuss forecasting failure time case of failure time censoring. In this study, we predict the future failure time by using the curve regression analysis where the s-curve, growth, and Logistic model is used. The proposed prediction method analysis used failure time for the prediction of this model. Model selection using the coefficient of determination and the mean square error were presented for effective comparison.

A Software Reliability Growth Model Based on Gompertz Growth Curve (Gompertz 성장곡선 기반 소프트웨어 신뢰성 성장 모델)

  • Park Seok-Gyu;Lee Sang-Un
    • The KIPS Transactions:PartD
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    • v.11D no.7
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    • pp.1451-1458
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    • 2004
  • Current software reliability growth models based on Gompertz growth curve are all logarithmic type. Software reliability growth models based on logarithmic type Gompertz growth curve has difficulties in parameter estimation. Therefore this paper proposes a software reliability growth model based on the logistic type Gompertz growth curie. Its usefulness is empirically verified by analyzing the failure data sets obtained from 13 different software projects. The parameters of model are estimated by linear regression through variable transformation or Virene's method. The proposed model is compared with respect to the average relative prediction error criterion. Experimental results show that the pro-posed model performs better the models based on the logarithmic type Gompertz growth curve.

Meteorological Determinants of Forest Fire Occurrence in the Fall, South Korea

  • Won, Myoung-Soo;Miah, Danesh;Koo, Kyo-Sang;Lee, Myung-Bo;Shin, Man-Yong
    • Journal of Korean Society of Forest Science
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    • v.99 no.2
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    • pp.163-171
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    • 2010
  • Forest fires have potentials to change the structure and function of forest ecosystems and significantly influence on atmosphere and biogeochemical cycles. Forest fire also affects the quality of public benefits such as carbon sequestration, soil fertility, grazing value, biodiversity, or tourism. The prediction of fire occurrence and its spread is critical to the forest managers for allocating resources and developing the forest fire danger rating system. Most of fires were human-caused fires in Korea, but meteorological factors are also big contributors to fire behaviors and its spread. Thus, meteorological factors as well as social factors were considered in the fire danger rating systems. A total of 298 forest fires occurred during the fall season from 2002 to 2006 in South Korea were considered for developing a logistic model of forest fire occurrence. The results of statistical analysis show that only effective humidity and temperature significantly affected the logistic models (p<0.05). The results of ROC curve analysis showed that the probability of randomly selected fires ranges from 0.739 to 0.876, which represent a relatively high accuracy of the developed model. These findings would be necessary for the policy makers in South Korea for the prevention of forest fires.

A new formulation for calculation of longitudinal displacement profile (LDP) on the basis of rock mass quality

  • Rooh, Ali;Nejati, Hamid Reza;Goshtasbi, Kamran
    • Geomechanics and Engineering
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    • v.16 no.5
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    • pp.539-545
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    • 2018
  • Longitudinal Displacement Profile (LDP) is an appropriate tool for determination of the displacement magnitude of the tunnel walls as a function of the distance to the tunnel face. Some useful formulations for calculation of LDP have been developed based on the monitoring data on site or by 3D numerical simulations. However, the presented equations are only based on the tunnel dimensions and for different quality of rock masses proposed a unique LDP. In the present study, it is tried to present a new formulation, for calculation of LDP, on the basis of Rock mass quality. For this purpose, a comprehensive numerical simulation program was developed to investigate the effect of rock mass quality on the LDP. Results of the numerical modelling were analyzed and the least square technique was used for fitting an appropriate curve on the derived data from the numerical simulations. The proposed formulation in the present study, is a logistic function and the constants of the logistic function were predicted by rock mass quality index (GSI). Results of this study revealed that, the LDP curves of the tunnel surrounded by rock masses with high quality (GSI>60) match together; because the rock mass deformation varies over an elastic range.

Predicting Suicidal Ideation in College Students with Mental Health Screening Questionnaires

  • Shim, Geumsook;Jeong, Bumseok
    • Psychiatry investigation
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    • v.15 no.11
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    • pp.1037-1045
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    • 2018
  • Objective The present study aimed to identify risk factors for future SI and to predict individual-level risk for future or persistent SI among college students. Methods Mental health check-up data collected over 3 years were retrospectively analyzed. Students were categorized as suicidal ideators and non-ideators at baseline. Logistic regression analyses were performed separately for each group, and the predicted probability for each student was calculated. Results Students likely to exhibit future SI had higher levels of mental health problems, including depression and anxiety, and significant risk factors for future SI included depression, current SI, social phobia, alcohol problems, being female, low self-esteem, and number of close relationships and concerns. Logistic regression models that included current suicide ideators revealed acceptable area under the curve (AUC) values (0.7-0.8) in both the receiver operating characteristic (ROC) and precision recall (PR) curves for predicting future SI. Predictive models with current suicide non-ideators revealed an acceptable level of AUCs only for ROC curves. Conclusion Several factors such as low self-esteem and a focus on short-term rather than long-term outcomes may enhance the prediction of future SI. Because a certain range of SI clearly necessitates clinical attention, further studies differentiating significant from other types of SI are necessary.

Cell Disruption of Microalgae by Low-Frequency Non-Focused Ultrasound (저주파 초음파를 이용한 미세조류 파쇄)

  • Bae, Myeong-Gwon;Choi, Jun-Hyuk;Park, Jong-Rak;Jeong, Sang-Hwa
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.19 no.2
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    • pp.111-118
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    • 2020
  • Recently, bioenergy research using microalgae, one of the most promising biofuel sources, has attracted much attention. Cell disruption, which can be classified as physical or chemical, is essential to extract functional ingredients from microalgae. In this study, we investigated the cell disruption efficiency of Chlorella sp. using low-frequency non-focused ultrasound (LFNFU). This is a continuously physical method that is superior to chemical methods with respect to environmental friendliness and low processing cost. A flat panel photobioreactor was employed to cultivate Chlorella sp. and its growth curve was fitted both with Logistic and Gompertz models. The temporal change in cell reduction by cell disruption using LFNFU was fitted with a Logistic model. The experimental conditions that were investigated were the initial concentration of microalgal cells, relative amplitude of output ultrasound waves, processing volume of microalgal cells, and initial pH value. The optimal conditions for the most efficient cell disruption were determined through the various tests.

A Study on Transportation Systems of Container Cargoes in Busan Port (부산항 컨테이너 화물수송체계에 관한 연구)

  • 오석기;오윤표;윤칠용
    • Journal of Korean Port Research
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    • v.15 no.1
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    • pp.19-26
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    • 2001
  • The purpose of this study is to improve the strategies for transportation systems of container cargoes in Busan port. Therefore, container cargoes forecasting is done through logistic methods based on past trends. In 2011, container cargoes demand was forecasted 8.791 million TEU(T/S including 12.559 million TEU). In order to improve transportation systems of container cargoes, the conclusions of this study can be summarized as follows ; \circled1 port facilities expansion, \circled2 diversity of container transport modes, \circled3 make up ICD and exclusive container roads, \circled4 the second Seoul-Busan Expressway.

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