• 제목/요약/키워드: best fit distribution

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Tests based on EDF statistics for randomly censored normal distributions when parameters are unknown

  • Kim, Namhyun
    • Communications for Statistical Applications and Methods
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    • 제26권5호
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    • pp.431-443
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    • 2019
  • Goodness-of-fit techniques are an important topic in statistical analysis. Censored data occur frequently in survival experiments; therefore, many studies are conducted when data are censored. In this paper we mainly consider test statistics based on the empirical distribution function (EDF) to test normal distributions with unknown location and scale parameters when data are randomly censored. The most famous EDF test statistic is the Kolmogorov-Smirnov; in addition, the quadratic statistics such as the $Cram{\acute{e}}r-von$ Mises and the Anderson-Darling statistic are well known. The $Cram{\acute{e}}r-von$ Mises statistic is generalized to randomly censored cases by Koziol and Green (Biometrika, 63, 465-474, 1976). In this paper, we generalize the Anderson-Darling statistic to randomly censored data using the Kaplan-Meier estimator as it was done by Koziol and Green. A simulation study is conducted under a particular censorship model proposed by Koziol and Green. Through a simulation study, the generalized Anderson-Darling statistic shows the best power against almost all alternatives considered among the three EDF statistics we take into account.

월강우량의 모의발생에 관한 연구 (Study on the Sequential Generation of Monthly Rainfall Amounts)

  • 이근후;류한열
    • 한국농공학회지
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    • 제18권4호
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    • pp.4232-4241
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    • 1976
  • This study was carried out to clarify the stochastic characteristics of monthly rainfalls and to select a proper model for generating the sequential monthly rainfall amounts. The results abtained are as follows: 1. Log-Normal distribution function is the best fit theoretical distribution function to the empirical distribution of monthly rainfall amounts. 2. Seasonal and random components are found to exist in the time series of monthly rainfall amounts and non-stationarity is shown from the correlograms. 3. The Monte Carlo model shows a tendency to underestimate the mean values and standard deviations of monthly rainfall amounts. 4. The 1st order Markov model reproduces means, standard deviations, and coefficient of skewness with an error of ten percent or less. 5. A correlogram derived from the data generated by 1st order Markov model shows the charaterstics of historical data exactly. 6. It is concluded that the 1st order Markov model is superior to the Monte Carlo model in their reproducing ability of stochastic properties of monthly rainfall amounts.

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국립산림과학원 제주시험림의 서어나무 수간형태와 수간곡선식 추정 (Development of Stem Profile and Taper Equation for Carpinus laxiflora in Jeju Experimental Forests of Korea Forest Research Institute)

  • 정영교;김대현;김철민
    • 농업생명과학연구
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    • 제44권4호
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    • pp.1-7
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    • 2010
  • 본 연구는 난대산림연구소의 제주시험림에 있는 서어나무 (Carpinus laxiflora)에 대한 개체목의 수간곡선식 추정 및 재적표를 개발하기 위하여 수행하였다. 최적의 추정식을 선택하기 위하여 Max & Burkhart식, Kozak식 및 Lee식을 적용하여 수간곡선식을 유도한 후, 각 식의 직경 추정에 대한 검정 통계량 및 실측치와 추정치간의 오차분포를 검증하였다. 그 결과 Max & Burkhart식 및 Lee식이 특정 구간에서 과대치 또는 과소 추정치를 보인데 반하여 Kozak식은 전구간에서 고른 분포를 보였다. 추정력이 가장 좋은 Kozak식을 활용하여 수피포함 재적표를 작성하였다.

전해 캐패시터의 최적 가속시험방법과 수명예측 (The best accelerated method and lifetime prediction of electrolytic capacitors)

  • 김하나;심찬호;김성준;윤중락;이헌용
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2005년도 제36회 하계학술대회 논문집 C
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    • pp.1945-1947
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    • 2005
  • This study considers find out best accelerated life testing and lifetime prediction of electrolytic capacitors. We proved about relation between failure and deterioration mechanism from last thesis. Beside we performed test that temperature and voltage press higher than allowance specification. Failure distribution acquired from those test. And wiebull function and Minitab program applied to accelerated constant and lifetime by means of calculation. At the result, goodness of fit affect to weibull function and acceleration factor therefore fitting is important factor in reliability testing.

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GALAXY SED FITTING

  • Denis, Burgarella;Mederic, Boquien;Veronique, Buat;Laure, Ciesla;Yannick, Rhoelly
    • 천문학논총
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    • 제32권1호
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    • pp.205-208
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    • 2017
  • Modelling and fitting the spectral energy distribution (SED) of galaxies or regions of galaxies is one of the most useful methods available to the astronomer nowadays. By modelling the SEDs and comparing the models to the observations, we can collect important information on the physical processes at play in the formation and evolution of galaxies. The models allow to follow the evolution of the galaxies from their formation on. The versatility of code is crucial because of the diversity of galaxies. The analysis is only relevant and useful if the models can correctly reproduce this diversity now and across (as best as possible) all redshifts. On the other hand, the code needs to run fast to compare several million or tens of millions of models and to select the best (on a probabilistic basis) one that best resembles the observations. With this important point in mind, it seems logical that we should efficiently make use of the computer power available to the average astronomer. For instance, it seems difficult, today, to model and fit SEDs without a parallelized code. We present the new Python version of CIGALE SED fitting code and its characteristics. CIGALE comes in two main flavours: CIGALE Classic to fit SEDs and CIGALE Model to create spectra and SEDs of galaxies at all redshifts. The latest can potentially be used in conjunction with galaxy evolution models of galaxy formation and evolution such as semi-analytic ones.

Prediction model for whistler chorus waves responsible for energetic electron acceleration and scattering

  • Kim, Jin-Hee;Lee, Dae-Young;Cho, Jung-Hee;Shin, Dae-Kyu
    • 천문학회보
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    • 제38권2호
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    • pp.94.1-94.1
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    • 2013
  • Whistler mode chorus waves, which are observed outside the plasmasphere of the Earth's magnetosphere, play a major role in accelerating and scattering energetic electrons in the radiation belts. In this study we developed a predicting scheme of the global distribution of chorus by using the Time History of Events and Macroscale Interactions during Substorms (THEMIS) satellite data. First, we determined global spatial distributions of chorus activity, and identified fit functions that best represent chorus intensities in specific L-MLT zones. Second, we determined the specific dependence of average chorus intensity on preceding solar wind conditions (e.g., solar wind speed, IMF Bz, energy coupling degree) as well as preceding geomagnetic states (as represented by AE, for example). Finally, we combined these two results to develop the predicting functions for the global distribution and intensity of chorus. Implementing these results in the radiation belt models should improve the local acceleration effect by chorus waves.

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Quantification of Fibers through Automatic Fiber Reconstruction from 3D Fluorescence Confocal Images

  • Park, Doyoung
    • 한국정보기술학회 영문논문지
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    • 제10권1호
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    • pp.25-36
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    • 2020
  • Motivation: Fibers as the extracellular filamentous structures determine the shape of the cytoskeletal structures. Their characterization and reconstruction from a 3D cellular image represent very useful quantitative information at the cellular level. In this paper, we presented a novel automatic method to extract fiber diameter distribution through a pipeline to reconstruct fibers from 3D fluorescence confocal images. The pipeline is composed of four steps: segmentation, skeletonization, template fitting and fiber tracking. Segmentation of fiber is achieved by defining an energy based on tensor voting framework. After skeletonizing segmented fibers, we fit a template for each seed point. Then, the fiber tracking step reconstructs fibers by finding the best match of the next fiber segment from the previous template. Thus, we define a fiber as a set of templates, based on which we calculate a diameter distribution of fibers.

Evaluation of the Population Distribution Using GIS-Based Geostatistical Analysis in Mosul City

  • Ali, Sabah Hussein;Mustafa, Faten Azeez
    • 대한원격탐사학회지
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    • 제36권1호
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    • pp.83-92
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    • 2020
  • The purpose of this work was to apply geographical information system (GIS) for geostatistical analyzing by selecting a semi-variogram model to quantify the spatial correlation of the population distribution with residential neighborhoods in the both sides of Mosul city. Two hundred and sixty-eight sample sites in 240 ㎢ are adopted. After determining the population distribution with respect to neighborhoods, data were inserted to ArcGIS10.3 software. Afterward, the datasets was subjected to the semi-variogram model using ordinary kriging interpolation. The results obtained from interpolation method showed that among the various models, Spherical model gives best fit of the data by cross-validation. The kriging prediction map obtained by this study, shows a particular spatial dependence of the population distribution with the neighborhoods. The results obtained from interpolation method also indicates an unbalanced population distribution, as there is no balance between the size of the population neighborhoods and their share of the size of the population, where the results showed that the right side is more densely populated because of the small area of residential homes which occupied by more than one family, as well as the right side is concentrated in economic and social activities.

Structural Model of Developing Human Resources Performance: Empirical Study of Indonesia States Owned Enterprises

  • HAERANI, Siti;SUMARDI, SUMARDI;HAKIM, Wardhani;HARTINI, HARTINI;PUTRA, Aditya Halim Perdana Kusuma
    • The Journal of Asian Finance, Economics and Business
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    • 제7권3호
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    • pp.211-221
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    • 2020
  • This study aims to analyze the effect of structural Person-Organization Fit and organizational justice on organizational commitment, job satisfaction, Organizational Citizenship Behavior and employee performance. This study is based on a quantitative approach by collecting data using a survey conducted on three SOE's companies in Indonesia that operate in Makassar City, namely Pelindo. Ltd (Port Company), PLN. Ltd (Electric Company) and Pertamina. Ltd (Oil and Gas Company), with a sample of 90 employees. The study population was all non-managerial permanent employees. Data analysis using Structural Equation Modeling. In structural relations, out of the nine direct tests, there were two insignificant relationships, and in all three hypotheses there was one not-supported hypothesis. When compared between person-organization Fit and Organizational Justice, it is found that organizational justice has a more critical role in building Human Resource performance compared to Person-Organization Fit, because organizational justice is better able to provide job satisfaction and make organizational commitment and OCB as a prerequisite for its formation to better Human Resources performance. With organizational justice, employees will feel more satisfied working, committed to the work and organization, and behaves as a supportive organizational citizen for the realization of the best performance for the interests of the organization going forward.

IR-UWB의 다중경로 환경에서감마분포를 이용한 거리 추정 알고리즘 (A Ranging Algorithm for IR-UWB in Multi-Path Environment Using Gamma Distribution)

  • 김진호;김형석;조성호
    • 한국통신학회논문지
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    • 제38B권2호
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    • pp.146-153
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    • 2013
  • IR-UWB 레이더는 송신안테나에서 UWB 대역을 갖는 임펄스를 방사하고 목표물에 부딪혀 수신안테나에 도달하는 지연시간, 즉 Time of Arrival(TOA)를 통해 목표물의 거리를 추정한다. 본 논문에서는 기존의 거리추정 알고리즘을 보완하여 실내 환경에서 더욱 정확한 거리 추정이 가능하게 하는 알고리즘을 제안한다. Novelda(사(社))의 NVA6000 UWB Transceiver를 장착한 IR-UWB Radar모듈을 사용하여 수신신호 데이터들을 취합하였다. 수신신호 데이터를 통해 얻은 Adjusted TOA(ATOA)를 히스토그램으로 나타내어 다중경로의 경향을 알아보고 그 결과 ATOA값들은 감마 분포의 특성을 갖는다는 점을 실험적으로 확인하였다. 이 감마 분포 특성을 이용하여 새로운 알고리즘을 제안하며, 기존의 알고리즘과의 성능비교를 수행하였다.