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Sample Design Using Imperfect Design Data, Robert Clark
Sample Design Using Imperfect Design Data, Robert Clark
Robert Clark
A well-designed sampling plan can greatly enhance the information that can be produced from a survey. Once a broad sample design is identified, specific design parameters such as sample sizes and selection probabilities need to be chosen. This is typically achieved using an optimal sample design, which minimizes the variance of a key statistic or statistics, expressed as a function of design parameters and population characteristics, subject to a cost constraint. In practice, only imprecise estimates of population characteristics are available, but the effects of this variability are usually ignored. A general approach to sample allocation allowing for imprecise design …
Developing The Design Of A Continuous National Health Survey For New Zealand, Robert Clark, Robert Templeton, Anne Mcnicholas
Developing The Design Of A Continuous National Health Survey For New Zealand, Robert Clark, Robert Templeton, Anne Mcnicholas
Robert Clark
Background A continuously operating survey can yield advantages in survey management, field operations, and the provision of timely information for policymakers and researchers. We describe the key features of the sample design of the New Zealand (NZ) Health Survey, which has been conducted on a continuous basis since mid-2011, and compare to a number of other national population health surveys. Methods A number of strategies to improve the NZ Health Survey are described: implementation of a targeted dual-frame sample design for better Maori, Pacific, and Asian statistics; movement from periodic to continuous operation; use of core questions with rotating topic …
Rail Track Infrastructure For Enhanced Speed - Analysis Design And Construction Challenges, Buddhima Indraratna, Sanjay Shrawan Nimbalkar, Jayan Sylaja J S Vinod
Rail Track Infrastructure For Enhanced Speed - Analysis Design And Construction Challenges, Buddhima Indraratna, Sanjay Shrawan Nimbalkar, Jayan Sylaja J S Vinod
Buddhima Indraratna
Rail is one of the largest transportation modes offering freight and passenger traffic in rapidly developing nations, including India. Conscious efforts to improve productivity, modernization and technology upgrading have led to an impressive growth in railways. Large-scale physical modeling, sophisticated numerical modeling and full-scale field monitoring often provide significant knowledge to better understand track performance and to extend the current state-of-the-art in design. A series of large-scale laboratory tests were conducted to establish relationships between (i) ballast breakage and train speed, (ii) ballast fouling and strength and (iii) interface strength and geogrids. Comprehensive field trials were carried out on instrumented …