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In many situations of survival and reliability test, the withdrawal of units from the test is pre-planned in order to to free up testing facilities for other tests, or to save cost and time. It is known that several risk factors (RiFs) compete for the immediate failure cause of items. In this paper, we derive an inference for a competing risks model (CompRiM) with a generalized type II progressive hybrid censoring scheme (GeTy2PrHCS). We derive the conditional moment generating functions (CondMgfs), distributions and confidence interval (ConfI) of the scale parameters of exponential distribution (ExDist) under GeTy2PrHCS with CompRiM. A real data set is analysed to illustrate the validity of the method developed here. From the data, it can be seen that the conditional PDFs of MLEs is almost symmetrical.
Subin Cho; Kyeongjun Lee. Exact Likelihood Inference for a Competing Risks Model with Generalized Type II Progressive Hybrid Censored Exponential Data. Symmetry 2021, 13, 887 .
AMA StyleSubin Cho, Kyeongjun Lee. Exact Likelihood Inference for a Competing Risks Model with Generalized Type II Progressive Hybrid Censored Exponential Data. Symmetry. 2021; 13 (5):887.
Chicago/Turabian StyleSubin Cho; Kyeongjun Lee. 2021. "Exact Likelihood Inference for a Competing Risks Model with Generalized Type II Progressive Hybrid Censored Exponential Data." Symmetry 13, no. 5: 887.
Roads are notable and responsible for the loss of biodiversity and disruption of wildlife habitats connectivity. Wildlife crossing structures (WCS) help wildlife move between habitats by connecting fragmented habitats. Their effectiveness is affected by various factors. Here, to identify methods for improving the effectiveness of wildlife crossing structures, we controlled the effect of intrinsic factors, such as size, that are difficult to improve in an already installed area, and then, evaluated the differences in extrinsic factors using 12 landscape characteristics. Our results show that 18 wildlife crossing structures were selected with propensity-score (PS) matching method. The surrounding landscape characteristics differed between high-effectiveness wildlife crossing structures and low-effectiveness wildlife crossing structures. Particularly, there was a significant difference between the ‘statutory protected area’ and the ‘edge’ index of the morphological spatial pattern analysis among the landscape characteristic variables derived within 1 km2 of wildlife crossing structures. We empirically demonstrate that characteristics around highly effective WCS, statutory protected areas are widely distributed, and the ratio of edge of MSPA is low (within 1 km2). Therefore, an important outcome of our research is the demonstration that management of WCS itself is important, but conservation of surrounding habitats and landscape management plans are also significant.
Hyunjin Seo; Chulhyun Choi; Kyeongjun Lee; Donggul Woo. Landscape Characteristics Based on Effectiveness of Wildlife Crossing Structures in South Korea. Sustainability 2021, 13, 675 .
AMA StyleHyunjin Seo, Chulhyun Choi, Kyeongjun Lee, Donggul Woo. Landscape Characteristics Based on Effectiveness of Wildlife Crossing Structures in South Korea. Sustainability. 2021; 13 (2):675.
Chicago/Turabian StyleHyunjin Seo; Chulhyun Choi; Kyeongjun Lee; Donggul Woo. 2021. "Landscape Characteristics Based on Effectiveness of Wildlife Crossing Structures in South Korea." Sustainability 13, no. 2: 675.
It is known that the lifetimes of items may not be recorded exactly. In addition, it is known that more than one risk factor (RisF) may be present at the same time. In this paper, we discuss exact likelihood inference for competing risk model (CoRiM) with generalized adaptive progressive hybrid censored exponential data. We derive the conditional moment generating function (ConMGF) of the maximum likelihood estimators of scale parameters of exponential distribution (ExpD) and the resulting lower confidence bound under generalized adaptive progressive hybrid censoring scheme (GeAdPHCS). From the example data, it can be seen that the PDF of MLE is almost symmetrical.
YoungSeuk Cho; Kyeongjun Lee. Exact Inference for an Exponential Parameter under Generalized Adaptive Progressive Hybrid Censored Competing Risks Data. Symmetry 2020, 12, 2005 .
AMA StyleYoungSeuk Cho, Kyeongjun Lee. Exact Inference for an Exponential Parameter under Generalized Adaptive Progressive Hybrid Censored Competing Risks Data. Symmetry. 2020; 12 (12):2005.
Chicago/Turabian StyleYoungSeuk Cho; Kyeongjun Lee. 2020. "Exact Inference for an Exponential Parameter under Generalized Adaptive Progressive Hybrid Censored Competing Risks Data." Symmetry 12, no. 12: 2005.
In this paper, we propose a new type censoring scheme named a generalized adaptive progressive hybrid censoring scheme (GenAdPrHyCS). In this new type censoring scheme, the experiment is assured to stop at a pre-assigned time. This censoring scheme is designed to correct the drawbacks in the AdPrHyCS. Furthermore, we discuss inference for one parameter exponential distribution (ExD) under GenAdPrHyCS. We derive the moment generating function of the maximum likelihood estimator (MLE) of scale parameter of ExD and the resulting lower confidence bound under GenAdPrHyCS.
Hyojin Lee; Kyeongjun Lee. Exact Likelihood Inference for an Exponential Parameter under Generalized Adaptive Progressive Hybrid Censoring. Symmetry 2020, 12, 1149 .
AMA StyleHyojin Lee, Kyeongjun Lee. Exact Likelihood Inference for an Exponential Parameter under Generalized Adaptive Progressive Hybrid Censoring. Symmetry. 2020; 12 (7):1149.
Chicago/Turabian StyleHyojin Lee; Kyeongjun Lee. 2020. "Exact Likelihood Inference for an Exponential Parameter under Generalized Adaptive Progressive Hybrid Censoring." Symmetry 12, no. 7: 1149.
In this paper, based on a doubly generalized Type II censored sample, the maximum likelihood estimators (MLEs), the approximate MLE and the Bayes estimator for the entropy of the Rayleigh distribution are derived. We compare the entropy estimators’ root mean squared error (RMSE), bias and Kullback–Leibler divergence values. The simulation procedure is repeated 10,000 times for the sample size n = 10, 20, 40 and 100 and various doubly generalized Type II hybrid censoring schemes. Finally, a real data set has been analyzed for illustrative purposes.
YoungSeuk Cho; Hokeun Sun; Kyeongjun Lee. An Estimation of the Entropy for a Rayleigh Distribution Based on Doubly-Generalized Type-II Hybrid Censored Samples. Entropy 2014, 16, 3655 -3669.
AMA StyleYoungSeuk Cho, Hokeun Sun, Kyeongjun Lee. An Estimation of the Entropy for a Rayleigh Distribution Based on Doubly-Generalized Type-II Hybrid Censored Samples. Entropy. 2014; 16 (7):3655-3669.
Chicago/Turabian StyleYoungSeuk Cho; Hokeun Sun; Kyeongjun Lee. 2014. "An Estimation of the Entropy for a Rayleigh Distribution Based on Doubly-Generalized Type-II Hybrid Censored Samples." Entropy 16, no. 7: 3655-3669.