Censoring Methodologies and Censored Data Analysis with Applications in the Engineering and Environmental Sciences

审查方法和审查数据分析在工程和环境科学中的应用

• 批准号: RGPIN-2015-06112
• 负责人: Davies, Katherine
• 金额: $ 0.8万
• 依托单位: University of Manitoba
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2016
• 资助国家: 加拿大
• 起止时间: 2016-01-01 至 2017-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=613951
• 关键词: Censoring; Methodologies; Censored; Data; Analysis

Censoring occurs when information about observations is either missing or only partially available. There are various types of censoring, some of which are incorporated into the design of a study, some of which occur naturally and one has no control over. Censored data arise in various fields, ranging from clinical trials in the pharmaceutical industry, to life-tests in the engineering sciences, to the modelling of the spread of a forest fire in the environmental sciences. It is therefore crucial to have the necessary tools to analyze such data and make useful inferences. A life-test, wherein an engineer puts units on test and attempts to make useful inferences about the units' lifetime distribution, is an effective technique employed in reliability analysis. In these tests, some type of censoring is often employed to save resources like time and money. One particular type of censoring is progressive censoring, which is a focus of this research program. In a progressive censoring experiment, surviving units are randomly removed throughout the life-test according to a prespecified scheme.  This type of censoring can be part of the design of a life-test and is more versatile than the traditional types of censoring, and hence is particularly useful.  On this topic, I introduce restricted progressive censoring schemes as well as investigate one-step plans, which are special plans entailing surviving units being randomly removed at one failure time. Despite the restrictive nature of these two types of censoring, these plans have particular benefits from practical points of view. Research departments in companies like Bombardier Inc., where reliability of components is critical and censoring is needed, will be able to benefit from this work. Alongside censoring methodologies is censored data analysis. Here, I focus on various non-parametric methods, that is, methods wherein little is assumed about the underlying distribution of the data. A particular class of tests are rank-based tests, i.e., some ordering of the data points is utilized. While such tests are well established in the literature, they have only recently been explored in the case of multi-dimensional data. My work thus investigates the use of such tests in the case of multivariate censored data where censoring occurs according to different mechanisms. This is especially important in the environmental sciences where many naturally occurring processes can be modelled as multi-dimensional point processes where oftentimes, some sort of censoring has occurred. For this reason, agencies addressing environmental concerns, such as Manitoba Hydro or Environment Canada, will find my work useful. This research program makes significant contributions to the areas of censoring methodologies and censored data analysis. Spanning inference, experimental design and data analysis, this work provides ideal problems to work on with students.

当有关观察的信息缺失或仅部分可用时，就会发生审查。审查有多种类型，其中一些被纳入研究设计中，其中一些是自然发生的，人们无法控制。审查数据出现在各个领域，从制药行业的临床试验，到工程科学的生命测试，再到环境科学中的森林火灾蔓延建模。因此，拥有必要的工具来分析此类数据并做出有用的推论至关重要。寿命测试是可靠性分析中采用的一种有效技术，其中工程师对单元进行测试并尝试对单元的寿命分布做出有用的推论。在这些测试中，通常采用某种类型的审查来节省时间和金钱等资源。一种特殊类型的审查是渐进式审查，这是本研究计划的重点。在渐进式审查实验中，根据预先指定的方案，在整个寿命测试过程中随机删除幸存的单元。  这种类型的审查可以成为寿命测试设计的一部分，并且比传统类型的审查更通用，因此特别有用。  在这个主题上，我介绍了受限的渐进审查方案，并研究了一步计划，这是一种特殊的计划，需要在一次故障时随机删除幸存的单元。尽管这两种审查具有限制性，但从实际角度来看，这些计划具有特殊的好处。庞巴迪公司等公司的研究部门将能够从这项工作中受益，其中组件的可靠性至关重要并且需要审查。 除了审查方法之外，还有审查数据分析。在这里，我重点关注各种非参数方法，即很少对数据的基本分布进行假设的方法。一类特定的测试是基于排名的测试，即利用数据点的某种顺序。虽然此类测试在文献中已经很成熟，但最近才在多维数据的情况下进行探索。因此，我的工作研究了在根据不同机制进行审查的多元审查数据的情况下使用此类测试。这在环境科学中尤其重要，其中许多自然发生的过程可以建模为多维点过程，其中经常发生某种审查。因此，解决环境问题的机构，例如马尼托巴水电局或加拿大环境部，会发现我的工作很有用。 该研究计划对审查方法和审查数据分析领域做出了重大贡献。这项工作涵盖推理、实验设计和数据分析，为学生提供了理想的解决问题。