Many Types Of Analysis Research Articles

Connections between A.K. Romney’s analyses of endogamy and other developments in log-linear models and network analysis

Abstract This paper examines contributions of A.K. Romney and associates to analyses of endogamy, and discusses the more general themes explored in these endogamy studies. The techniques used in these papers are relevant to many types of analysis of contingency tables, and to other settings such as social mobility. Some of these connections are explored here, all with a view to the importance of the margins of the table for different kinds of analysis. In particular, the paper discusses descriptive and analytical uses of classical iterative proportional fitting (IPF), some specific log-linear models, and the margins of sociomatrices. The paper also includes analyses of example data.

Spatial and temporal variability of rainfall related to a third-order Markov model

Many types of analysis require rainfall data, which must often be generated to overcome limitations in the historical record. The ability to model outlying rainfall years satisfactorily is particularly important in risk studies. We describe a rainfall generator with this ability, based on a third-order Markov process, and we show how the fitted parameters of the model vary for an illustrative sample of 18 sites with highly contrasting climates. Some of the parameters of the model show patterns that are characteristic of the climate type. The model should thus be suitable for interpolating rainfall data where they do not exist. We also fitted the model to subsets of some long data records to illustrate the marked changes in rainfall characteristics that have occurred in some locations over the last 70 years, and to help understand the nature of these changes.

Faster and cheaper PCR on a standard thermocycler.

The PCR conditions have been optimized to make the process faster and more economical. When short DNA fragments are to be amplified, the time of denaturation, annealing and extension steps can be as short as 1 s each, and the yield of PCR product is still high, sufficient for many types of analysis. The PCR can be done even in a reaction volume as low as 1 microliter. The recommended volume, 2.5 microliters or 5 microliters, allows significant savings in the laboratory budget especially for laboratories which use PCR frequently and on a large scale.

Twelve-year follow-up of respondents in a sample survey in peninsular Malaysia

"This note reports the experience of an attempt to find and re-interview in late 1988 and early 1989, as part of the Second Malaysian Family Life Survey (MFLS-2), the female respondents to the 1976-77 Malaysian Family Life Survey (MFLS-1) and a sample of their adult children aged 18 or older.... We discuss the field methods used to track the panel members and their adult children, report follow-up rates and analyze the selectivity of attrition from the panel, using data from the MFLS-1 on characteristics of both the missing and the re-interviewed respondents and their families. We then discuss the degree to which these results might be generalized to other such attempts at re-contacting survey respondents."

Parametric analysis of histograms measured in flow cytometry.

Flow cytometric histograms frequently consist of several components that show various degrees of overlap. For many types of analysis it is of great importance to decompose the original histogram into its components. To that purpose, we investigated the maximum likelihood approach in detail. It is shown that the iterative method to solve the maximum likelihood equations is well behaved for a variety of initial values. Algorithms to obtain initial values are presented, and the performance of the method is tested when applied to the analysis of DNA measurements from heterogeneous cell populations that differ with respect to DNA content.

On the shape of directional data sets

Existing methods for the analysis of the shape of directional data sets, primarily paleosecular variation data, tend to have serious inconsistencies in their application and in general are difficult to apply. The question of whether or not a given data set is distributed in a circular manner about its mean is important in many types of analysis, particularly so, since circularity is a necessary condition for the application of the statistical techniques of Fisher (1953). A new statistic, called the eccentricity, is developed and shown to offer information as to the shape of a distribution of directions. The eccentricity statistic does not depend on choice of classes or intervals, is invariant to rotations of the distribution about the mean directions, is simple to apply, and is easily understood in terms of a simple physical analogy. The method is applied to 112 Hawaiian lavas (Doell and Cox, 1965). The analysis shows good agreement with a model in which magnetic variations in Hawaii are a consequence of dipole wobble only, with no significant contributions from the nondipole field.

Generalised system model for slipring machines

The general structure of a circuit model of a slipring machine is established in this paper. The model is shown to be advantageous in many types of analysis of a machine when it is a part of a system. A specific circuit model of a synchronous machine (which was derived from Park's equations) has advantages in the stability analysis of multimachine power systems. The paper provides a more general and basic circuit model (applicable to any slipring machine) utilising the actual physical parameters of the machine. This is done with the view to extending the application of the circuit model to the study of asymmetrical faults or unbalanced operation. In such an analysis, the use of transformed αβ0 or dq0 components has no advantages. The advantages of this model in transient analysis over the existing models are shown to be the ease of formulation of the system equations, the elimination of the necessity to invert a time-varying inductance matrix and the ease of obtaining analytical solutions in a linear analysis. The specific circuit model, used for stability analysis, is actually derived from the general circuit model presented. Further, the model is also applicable to any slipring machine with or without m.m.f. harmonics.

Efficient Continuous A.C. Arc

While d.c. arc excitation has been conventional for many types of analysis, the erratic volatilization characteristics have always demanded rigidly standardized methods and an unnecessarily high amount of preliminary development. A high amperage a c. arc ( Sustaining Arc) has been developed for maximum output at high electrical efficiency. The unit exhibits the greatest improvement for heavy or refractory elements. In general, background is reduced up to 20%, sensitivity improved by 10 to 30%, and reproducibility enhanced by 30 to 100% over a wide range of materials encountered in a commercial laboratory.