Applied Mathematics Commons^™

A New Partitioning Around Medoids Algorithm, Mark J. Van Der Laan, Katherine S. Pollard, Jennifer Bryan

U.C. Berkeley Division of Biostatistics Working Paper Series

Kaufman & Rousseeuw (1990) proposed a clustering algorithm Partitioning Around Medoids (PAM) which maps a distance matrix into a specified number of clusters. A particularly nice property is that PAM allows clustering with respect to any specified distance metric. In addition, the medoids are robust representations of the cluster centers, which is particularly important in the common context that many elements do not belong well to any cluster. Based on our experience in clustering gene expression data, we have noticed that PAM does have problems recognizing relatively small clusters in situations where good partitions around medoids clearly exist. In this …

Three-Dimensional Reconstructions Of Tadpole Chondrocrania From Histological Sections, Gary P. Radice, Mary Kate Boggiano, Mark Desantis, Peter M. Larson, Joseph Oppong, Matthew T. Smetanick, Todd M. Stevens, James Tripp, Rebecca A. Weber, Michael Kerckhove, Rafael O. De Sá

Biology Faculty Publications

Reconstructing three dimensional structures (3DR) from histological sections has always been difficult but is becoming more accessible with the assistance of digital imaging. We sought to assemble a low cost system using readily available hardware and software to generate 3DR for a study of tadpole chondrocrania. We found that a combination of RGB camera, stereomicroscope, and Apple Macintosh PowerPC computers running NIH Image, Object Image, Rotater. and SURFdriver software provided acceptable reconstructions. These are limited in quality primarily by the distortions arising from histological protocols rather than hardware or software.

Modelling And Risk Analysis Of The Western Rock Lobster (Panulirus Cygnus) Fishery Of Western Australia, C. S. Yap

Theses: Doctorates and Masters

The predictive power for short-term forecasting of selected biomass dynamic models was examined using the standardised catch and effort data from the 1944/45 to 1990/91 season of the western rock lobster. Risk analysis of the fishery based on the predicted fishing efforts with the Deriso-Schnute delay-difference model indicates a high probability of recruitment failure. Some hypothetical management strategies of reducing fishing effort were evaluated by taking into consideration the total catch and biological risk to the fishery.

Msda A Machinery Selection Decision Aid For Stubble Management Practices, Linda Leonard, Andrew Green

Grain and other field crops published reports

MSDA is a user friendly program developed to help farmers predict stubble outcomes before acting on their management practice. This manual is an accompaniment to a computer program designed on Micorsoft Excel-macros. Its aim is to help farmers assess their current machinery and stubble handling ability and view options that may be adopted as best practice for their properties.

The program is designed with the complete season in mind. Information is gathered on the full complement of machinery used from harvest through to seeding, to allow farmers to see all choices available and enable them to choose the best system …

Approximation Methods For Singular Diffusions Arising In Genetics, Nacer E. Abrouk

Mathematical Sciences Technical Reports (MSTR)

Stochastic models in population genetics leading to diffusion equations are considered. When the drift and the square of the diffusion coefficients are polynomials, an infinite system of ordinary differential equations for the moments of the diffusion process can be derived using the Martingale property. An example is provided to show how the classical Fokker-Planck Equation approach may not be appropriate for this derivation. A Gauss-Galerkin method for approximating the laws of the diffusion, originally proposed by Dawson (1980), is examined. In the few special cases for which exact solutions are known, comparison shows that the method is accurate and the …

Miscellaneous Publication 17/91 - Mudas - Model Of An Uncertain Dryland Agricultural System: A Description, R. S. Kingwell, A. D. Bathgate

Farm Systems and Economics research reports

In the early 1980s, the Department of Agriculture developed a mixed integer whole-farm mathematical programming model of the dryland farming system in the eastern wheatbelt of Western Australia (Morrison et al. 1986). The model named MIDAS (Model of an Integrated Dryland Agricultural System) was constructed, tested and scrutinised by a multi-disciplinary team of researchers, advisers, farm management consultants and farmers (Kingwell 1987a). The model described in some detail the biology and finances of the dryland farming system in an average season and calculated profit-maximising farm plans.

MIDAS remains an often used tool in research and extension, being applied to many …

Objective Measurement And The Stud Breeder, B R. Beetson

Journal of the Department of Agriculture, Western Australia, Series 4

The movement towards sale of wool by certificate and sample highlights the significance of objective measurement in the Merino stud breeders' selection of his top rams.

This article suggests how stud breeders should use the Department of Agriculture's Flock Testing Service to gain genetic progress in wool producing ability without loss of visual buyer appeal.

Studs' use of the service will be evaluated in 1974.

A Mathmatical Model Of Primary Productivity And Limnological Patterns In Lake Mead, Lorne G. Everett

Publications (WR)

The temporal and spatial changes in chemical and biological properties of Lake Mead have been investigated, thereby indicating the sources of water pollution and the time of highest pollution potential. Planktonic organisms have been shown to indicate the presence of water problems. Macro- and micro-nutrient analyses have shown that primary productivity is not inhibited by limiting concentrations. A mathematical model has been developed, tested with one set of independent data, and shown worthy of management utility. Although the model works very well for the Lake Mead area, the physical reality of the Multiple Linear Regression equation should be tested on …

Metric Conversion For Agriculture, Department Of Agriculture, Western Australia

Journal of the Department of Agriculture, Western Australia, Series 4

Farmers are already becoming involved with metric units and by 1974 conversion of the farming industry will be well advanced. Wool sales converted to metric measurements in August, 1971, and sales by the various grain marketing boards will be largely in metric terms in the 1972 harvest. Weather information to the public has been given in metric terms since September 1.

Select On Fleece Weight And Cull The Low Producers, W L. Mcgarry

Journal of the Department of Agriculture, Western Australia, Series 4

EFFICIENT calling of maiden ewes before they join the breeding flock is an essential part of any policy of flock improvement.

Removal of the low wool producers should be one of the first considerations when culling the flock.

Facts And Figures For The Man On The Land, J A. Mallett

Journal of the Department of Agriculture, Western Australia, Series 4

FARM or station life calls for the exercise of so many different skills that the farmer or pastoralist is usually an accomplished handyman.

For those whose schooldays are far behind them however, the most difficult part of many tasks is that of dealing with the calculations involved, and it is hoped that these facts and figures will serve as a handy aid to those whose mathematical ability has not kept pace with their manual and technical skill.