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The n-dimensional pseudospheres are the surfaces in Rn+l given by the equations x12+x22+...+xk2-xk+12-...-xn+12=1(1 ≤ k ≤ n+1). The cases k=l, n+1 give, respectively a pair of hyperboloids, and the ordinary n-sphere. In the first chapter we consider the pseudospheres as surfaces h En+1,k, where Em,k=Rk x (iR)m-k, and investigate their geometry in terms of the linear algebra of these spaces.... [Thesis or Dissertation]

In this paper we present a computationally e cient method for nding multiple structural breaks at unknown dates based on regression trees. We outline the procedure and present the results of a simulation study to assess the performance of the method and to compare it with the procedure proposed by Bai and Perron. We nd the tree-based method performs well in long series which are impractical... [Journal Article]

Considerable scope exists for the reduction of the primary and secondary costs associated with crop protection, by the formulation of judicious fungicide application regimes. The design, building and operation of a farm-level computer-based information system is described, the purpose of which is to help the farmer make rational spraying decisions. The system makes use of a simulation model... [Thesis or Dissertation]

Industrial Research Limited and Telecom NZ LimitedThe placement of base stations is an important issue in planning wireless systems because it has a significant influence on overall system performance. In order to achieve good performance in an interference limited CDMA system, a large number of variables must be considered simultaneously during the planning stage. A traditional manual planning approach that involves an iterative application... [Thesis or Dissertation]

This thesis describes the Operational Harvest Scheduling (OHS) problem and develops an algorithm that solves instances of the problem. The solution to an OHS problem is an Operational Harvest Schedule (OHS). An OHS: ² assigns forest harvesting crews to locations within a forest in the short-term (4-8 weeks); ² instructs crews to harvest specific log-types and allocates these log-types to... [Thesis or Dissertation]

Meat quality is a subject of growing interest. Important meat quality parameters include colour, tenderness, texture, flavour and odour, water holding capacity and juiciness. The quantification of meat quality is a challenge of major importance in the meat industry. The ability to meet consumer expectations by providing quality products and maintaining the consistency of products is the basis... [Thesis or Dissertation]

There has been considerable recent interest in geometric function theory, nonlinear partial differential equations, harmonic mappings, and the connection of these to minimal energy phenomena. This work explores Nitsche's 1962 conjecture concerning the nonexistence of harmonic mappings between planar annuli, cast in terms of distortion functionals. The connection between the Nitsche problem... [Thesis or Dissertation]

There has been considerable recent interest in geometric function theory, nonlinear partial differential equations, harmonic mappings, and the connection of these to minimal energy phenomena. This work explores Nitsche's 1962 conjecture concerning the nonexistence of harmonic mappings between planar annuli, cast in terms of distortion functionals. The connection between the Nitsche problem... [Thesis or Dissertation]

Sulphur (S) is an important plant nutrient, and is often deficient for plant growth on the yellow-brown pumice soils of the Central North Island, New Zealand. In order to remove this limitation to plant growth in the most efficient and economic way it is necessary to understand the fate of fertiliser S applied to these soils. The experiments reported in this thesis aimed to determine the fate... [Thesis or Dissertation]

We use a previously validated cardiovascular system (CVS) model and parameter identification method to identify the pig-specific parameters during induced endotoxic shock. Six anesthetized healthy pigs weighing 20-30 kg received a 0.5- mg/kg endotoxin infusion over a period of 30 mins from T0 to T30. Only right heart measurements were obtained and thus significantly less data was available for... [Conference Paper]

A general differential equation model of the temporal evolution of a pest population density when subjected to control measures using a pesticide, is investigated. The model is based on logistic growth combined with population dispersal described by diffusion, and pesticide action is characterised by its LD90 toxicity measure and a consumption limited by a saturation pesticide density.... [Book]

Smoothed particle hydrodynamics (SPH) is becoming increasingly common in the numerical simulation of complex fluid flows and an understanding of the errors is necessary. Recent advances have established techniques for ensuring completeness conditions (low-order polynomials are interpolated exactly) are enforced when estimating property gradients, but the consequences on errors have not been... [Conference Item]

Quantitative microbial risk analysis modelling is increasingly being used in food safety as a tool to evaluate health risks. Accurately forming such models can be very difficult due to the uncertainty in the available data. Second order Monte Carlo simulation allows for the inclusion of this uncertainty and separates it from the variability incorporated in the model. This modelling process is... [Conference Paper]

Quantitative microbial risk analysis modelling is increasingly being used in food safety as a tool to evaluate health risks. Accurately forming such models can be very difficult due to the uncertainty in the available data. Second order Monte Carlo simulation allows for the inclusion of this uncertainty and separates it from the variability incorporated in the model. This modelling process is... [Conference Paper]

In this work, we examine the polynomial invariants of the special Euclidean group in three dimensions, SE(3), in its action on multiple screw systems. We look at the problem of finding generating sets for these invariant subalgebras, and also briefly describe the invariants for the standard actions on R^n of both SE(3) and SO(3). The problem of the screw system action is then approached using...

Uncertainty in estimating a true population parameter from survey data is a result of imperfect detection, imperfect observation, spatial and temporal variation, and sampling error. Some level of uncertainty is inevitable in all surveys. We discuss the sources of uncertainty in surveys of bird counts and show how we have used Monte Carlo simulations to illustrate the effect of uncertainty. [Conference Paper]

Sampling for rare events, such as a new weed incursion, can be surprisingly efficient when adaptive, unequal probability survey designs are used. Spatially explicit habitat models and expert knowledge of weedy species can be used to identify areas of varied survey intensity. We introduce a GIS-based tool that can be used for designing such a survey. The user-friendly tool interfaces (behind the... [Conference Item]

An open access copy of this article is available and complies with the copyright holder/publisher conditions.We generalise to the setting of 3-graphs a combinatorial analogue of the Jordan curve theorem due to Stahl [9, 10]. More specifically, using combinatorial techniques only, we give a graph theoretic version of the theorem that the first Betti number of a surface is the largest number of closed curves that can be drawn on the surface without dividing it into two or more regions. [Journal Article]

An open access copy of this article is available and complies with the copyright holder/publisher conditions.The authors obtain some new functional inequalities for the Hersch–Pfluger distortion function in the theory of plane quasiconformal mappings, thus solving some recent conjectures. [Journal Article]

An open access copy of this article is available and complies with the copyright holder/publisher conditions.We look at fitting regression models using data from stratified cluster samples when the strata may depend in some way on the observed responses within clusters. One important subclass of examples is that of family studies in genetic epidemiology, where the probability of selecting a family into the study depends on the incidence of disease within the family. We develop the survey-weighted... [Journal Article]

An open access copy of this article is available and complies with the copyright holder/publisher conditions.A strong form of continuity of functions between topological spaces is introduced and studied. It is shown that in many known results, especially closed graph theorems, functions under consideration are R-continuous. Several results in the literature concerning strong continuity properties are generalized and/or improved. [Journal Article]

An open access copy of this article is available and complies with the copyright holder/publisher conditions.Using a projection approach, we obtain an asymptotic information bound for estimates of parameters in general regression models under choice-based and two-phase outcome-dependent sampling. The asymptotic variances of the semiparametric estimates of Scott and Wild (1997, 2001) are compared to these bounds and the estimates are found to be fully efficient. [Journal Article]

An open access copy of this article is available and complies with the copyright holder/publisher conditions.VoR - Version of RecordThe use of microwave heating to initiate combustion synthesis has been increasingly investigated in recent years because of its advantages over traditional methods. A simple mathematical model is used to model these experiments. The microwave power absorption term is modelled as the product of an Arrhenius reaction term with a function that decays exponentially with distance. The former... [Journal Article]

An open access copy of this article is available and complies with the copyright holder/publisher conditions.VoR - Version of RecordTo examine the long-term effects of fertiliser application on pasture growth under grazing, a mathematical representation of the pasture ecosystem is created and analysed mathematically. From this the nutrient application level needed to maintain a given stocking rate can be determined, along with its profitability. Feasible stocking levels and fertiliser application rates are investigated and... [Journal Article]

An open access copy of this article is available and complies with the copyright holder/publisher conditions.VoR - Version of RecordIt is known that a threshold policy (or trunk reservation policy) is optimal for Erlang’s loss system under certain assumptions. In this paper we examine the robustness of this policy under departures from the standard assumption of exponential service times (call holding times) and give examples where the optimal policy has a generalized trunk reservation form. [Journal Article]