Estimation of the parameters of a population from a multi-censored sample

The specific problems in this thesis were the estimation of parameters of univariate populations from samples where multiple-points of censorship occur. The case of a sample subjected to multiple points of censorship (on the right) may be described as follows: A sample of n items is tested; when the first one fails at time x1, a random sample of k1 is withdrawn from the n-1 items still in test; the remaining items are observed until the second item fails at time x2, when k2 items are withdrawn; and the process of withdrawing a prescribed number k i at the time xi when the i-th failure occurs continues until the r-th failure occurs at time xr, at which time the remainder of the items are withdrawn;The method of maximum likelihood is employed to estimate the parameters for the exponential, the normal, and the gamma distributions. These estimates are, in certain cases, difficult to obtain. They require iteration; therefore, certain practical limitations exist for their use. A new method of solving the likelihood equations for the normal distribution is introduced, and a Delta function is tabulated to facilitate the solution. An extension of the censorship procedure to another general type is considered for estimation by the method of maximum likelihood;The non-parametric estimate of the probability of surviving (quantiles) is obtained, and a general method of estimation based on the quantiles is presented, which will yield reasonable results when the method of maximum likelihood cannot be used, and which will be reasonably efficient in comparison to the maximum likelihood estimates when these are available for comparison. It is shown that the method of estimation from the quantiles yields the maximum-likelihood estimate for the exponential distribution for all rules of censorship and the uniform distribution for a random sample. The quantile method is asymptotically equivalent to the methods of maximum likelihood for the parameters of the normal distribution. The method yields a simple result (best linear unbiased estimate) for the uniform distribution with single or multi-censorship. This is an advantage over the maximum-likelihood method, which does not furnish a simple result;The above results are illustrated by a number of examples taken from industrial experiments. It is possible, through the techniques presented, to utilize small samples such as exist in industry, and also, although curtailment exists, to have assurance of a certain number of complete life times from which to make estimates even where no prior knowledge---other than the distributional form---exists on the life times of the items tested

Baseline and greenhouse-gas emissions in extensive livestock enterprises, with a case study of feeding lipid to beef cattle

For accurate calculation of reductions in greenhouse-gas (GHG) emissions, methodologies under the Australian Government's Carbon Farming Initiative (CFI) depend on a valid assessment of the baseline and project emissions. Life-cycle assessments (LCAs) clearly show that enteric methane emitted from the rumen of cattle and sheep is the major source of GHG emissions from livestock enterprises. Where a historic baseline for a CFI methodology for livestock is required, the use of simulated data for cow-calf enterprises at six sites in southern Australia demonstrated that a 5-year rolling emission average will provide an acceptable trade off in terms of accuracy and stability, but this is a much shorter time period than typically used for LCA. For many CFI livestock methodologies, comparative or pair-wise baselines are potentially more appropriate than historic baselines. A case study of lipid supplementation of beef cows over winter is presented. The case study of a control herd of 250 cows used a comparative baseline derived from simple data on livestock numbers and class of livestock to quantify the emission abatement. Compared with the control herd, lipid supplementation to cows over winter increased livestock productivity, total livestock production and enterprise GHG emissions from 990 t CO2-e to 1022 t CO2-e. Energy embodied in the supplement and extra diesel used in transporting the supplement diminished the enteric-methane abatement benefit of lipid supplementation. Reducing the cow herd to 238 cows maintained the level of livestock production of the control herd and reduced enterprise emissions to 938 t CO2-e, but was not cost effective under the assumptions of this case study

Analysis of Weekday, Weekend, and Holiday Accident Frequencies

Trends in recent years have indicated that a significant percentage of weekend traffic is recreational and that the proportion of weekend trips is increasing. The energy crisis in late 1973, and the associated reduction in speed limit on March 1, 1974, affected weekend travel. A previous study by the Division of Research revealed that significant reductions in the number and rates of highway accidents, fatalities, and injuries coincided with the period of time generally referred to as the energy crisis . Lower speeds were considered to be a primary factor in the reduction of accidents. An alteration in weekend and holiday trips was suspected of contributing to the reduction of accident rates; however, information was lacking from which to make this determination. A comparison of accidents during weekday, weekend, and holiday periods was made; most of the data were for rural sections of two-lane roads, four-lane roads, interstate routes, and toll roads. On rural roads, the largest number of accidents have occurred on Saturdays, Fridays, and Sundays. Tuesdays generally had the lowest number of accidents. Fatal accidents on two-lane roads occurred in similar random patterns of distribution during the week. The highest rates for two-lane roads were on Sundays and Saturdays, and the rates for expressways (interstates and toll roads) were the highest on Sundays. Fatality rates were distributed similarly to the rates of all accidents. The percentage of accidents on weekends decreased steadily from 35 in 1973 to 32 in 1976. likewise, the percentage of fatalities on weekends showed gradual decreases. Accident rates on weekends were substantially higher than on weekdays. Rates of fatal and an accidents were lower during holiday periods than during weekends not involving holidays. Holiday periods had fewer accidents per day than weekends but had more accidents per day than weekdays. Traffic volumes, however, were significantly greater during holidays than on either weekends or weekdays

Baseline and greenhouse-gas emissions in extensive livestock enterprises, with a case study of feeding lipid to beef cattle

For accurate calculation of reductions in greenhouse-gas (GHG) emissions, methodologies under the Australian Government's Carbon Farming Initiative (CFI) depend on a valid assessment of the baseline and project emissions. Life-cycle assessments (LCAs) clearly show that enteric methane emitted from the rumen of cattle and sheep is the major source of GHG emissions from livestock enterprises. Where a historic baseline for a CFI methodology for livestock is required, the use of simulated data for cow-calf enterprises at six sites in southern Australia demonstrated that a 5-year rolling emission average will provide an acceptable trade off in terms of accuracy and stability, but this is a much shorter time period than typically used for LCA. For many CFI livestock methodologies, comparative or pair-wise baselines are potentially more appropriate than historic baselines. A case study of lipid supplementation of beef cows over winter is presented. The case study of a control herd of 250 cows used a comparative baseline derived from simple data on livestock numbers and class of livestock to quantify the emission abatement. Compared with the control herd, lipid supplementation to cows over winter increased livestock productivity, total livestock production and enterprise GHG emissions from 990 t CO2-e to 1022 t CO2-e. Energy embodied in the supplement and extra diesel used in transporting the supplement diminished the enteric-methane abatement benefit of lipid supplementation. Reducing the cow herd to 238 cows maintained the level of livestock production of the control herd and reduced enterprise emissions to 938 t CO2-e, but was not cost effective under the assumptions of this case study

The relevance of ERTS-1 data to the state of Ohio

There are no author-identified significant results in this report

Understanding the causes of local disputes in paediatrics to develop pathways to dispute resolution in North East Scotland. [NHS Grampian R&D Poster]

Conflicts between parents and clinicians over the care of children with life-limiting conditions can reach the point where courts must intervene, causing distress, unwanted media attention and costs. This NHS Grampian case study sought to understand reasons for disputes, identify potential solutions and reduce the risk of a case coming before a Scottish court. In-depth semi-structured interviews with 20 participants (a mix of NHS Grampian clinicians and parents) were conducted from which qualitative data were obtained on their experiences of and views on disagreements about care, how decision-making is handled, what works well and what might improve existing approaches

Development and fabrication of a Bi-2223 racetrack coil for generator applications

The development and fabrication of a layer-wound, epoxy-impregnated Bi-2223 high-temperature superconducting (HTS) racetrack coil which generates 40,000 ampere-turns of magnetomotive force (MMF) at 25 K is described. The coil was wound using Ag-sheathed Bi-2223 tape conductor laminated with copper foils for strength enhancement and insulated using a paper-wrap method. After epoxy impregnation, the coil was tested over a range of 16--25 K in a vacuum dewar using a closed-cycle helium refrigeration system. Descriptions of the tape lamination and insulation processing, the coil winding and impregnation, and the experimental test setup are given