Jennifer Brown

Jennifer Brown
University of Canterbury | UC · Department of Mathematics and Statistics

About

120
Publications
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Publications

Publications (120)
Article
Full-text available
A spatial sampling design determines where sample locations are placed in a study area so that population parameters can be estimated with good precision. Spatially balanced designs draw samples with good spatial spread and provide precise results for commonly used estimators when surveying natural resources. In this article, we propose a new sampl...
Article
Multiple auxiliary information-based (MAIB) memory-type charts are proposed with fixed and variable sampling intervals for an improved monitoring of the process mean, which include adaptive/nonadaptive cumulative sum (CUSUM) and exponentially weighted moving average (EWMA) charts. These control charts are constructed based on a unique uniformly min...
Article
In quality control applications, the quality of a product may effectively be characterized by a relationship between one or more variables that is typically referred to as a profile. In this paper, we propose two control charts, namely the maximum multivariate EWMA (MEWMA) and maximum double MEWMA charts for monitoring the parameters of a multivari...
Data
Supplementary material for quasi-random ranked set sampling
Article
This article presents a quasi-random ranked set sampling approach based on the Halton sequence for natural resource surveys. A design-based variance estimator for the sample mean is also presented.
Article
In some sampling situations, the survey can result in an estimate of zero when it is known that the parameter being estimated is close to, but not equal to, zero. Examples include searching for rare animals or plants where the species is known to exist but all sample units failed to detect any activity. One way to deal with this is to ignore these...
Conference Paper
Full-text available
A spatial sampling design determines where sample locations are placed in a study area. The main objective is to select sample locations in such a way that valid scientific inferences can be made to all regions of the study area. A sample that is well-spread over the study area is called a spatially balanced sample. Spatially balanced sampling desi...
Article
We present an algorithm for learning oblique decision trees, called HHCART(G). Our decision tree combines learning concepts from two classification trees, HHCART and Geometric Decision Tree (GDT). HHCART(G) is a simplified HHCART algorithm that uses linear structure in the training examples, captured by a modified GDT angle bisector, to define spli...
Conference Paper
Full-text available
Ranked set sampling is a design that can increase sample efficiency by forcing sample coverage over the range of response values in the population. Balanced acceptance sampling (BAS) has a similar aim, with sample efficiency coming from ensuring coverage, where coverage is considered in terms of spatial spread over the sample space. Here we describ...
Article
Full-text available
A new spatially balanced sampling design for environmental surveys is introduced, called Halton iterative partitioning (HIP). The design draws sample locations that are well spread over the study area. Spatially balanced designs are known to be efficient when surveying natural resources because nearby locations tend to be similar. The HIP design us...
Article
Full-text available
The study of avian integumentary colouration can offer insight into dietary and metabolic processes as well as fitness in focal species. Yet, we know relatively less about the system of feather colouration in African birds in comparison to Europe, North America and the neotropics. In this study, we biochemically characterised and quantified the pig...
Article
This article presents a modification of balanced acceptance sampling (BAS) that causes inclusion probabilities to better approximate targeted inclusion probabilities. A new sample frame constructor for BAS is also introduced from which equi-probable spatially balanced samples are drawn.
Article
Social media platforms are important actors in the development of alcohol marketing techniques. While public health research has documented the activities of brands and consumers related to alcohol promotion and consumption on social media, there remains the need to develop an account of the native, participatory and data-driven advertising model o...
Article
Full-text available
In ecological studies, the population of interest is often spread over a large area. In these studies, obtaining a sample with good spatial coverage is an important feature in the design of a survey. In most cases adjacent, or neighbouring, units are more similar than units further apart and the resulting spatial autocorrelation should be taken int...
Article
Full-text available
http://archimer.ifremer.fr/doc/00410/52102/52808.pdf Bivalves are important components of benthic marine and freshwater ecosystems throughout the world. One of the most exploited bivalves used for human consumption is manila clam (Venerupis philippinarum). In Arcachon Bay (SW France), commercial fishers and scientists have developed a monitoring s...
Article
We present a new inverse sampling design for surveys of rare events, Gap Based Inverse Sampling. In the design, sampling stops if, after a predetermined interval, or gap, no new rare events are found. The length of the gap that follows after finding a rare event is used as a way of limiting sample effort. We present stopping rules using decisions b...
Conference Paper
Full-text available
A collaborative joint management approach is being developed for the Manila clam (Ruditapes philippinarum) resource in Arcachon Bay between scientists and fishermen. The basis of decisions in this management framework is information on the resource from data collected in field surveys. It is relatively time consuming and costly for the local commun...
Article
Objective: Since 2012, all community care recipients in New Zealand have undergone a standardised needs assessment using the Home Care International Residential Assessment Instrument (interRAI-HC). This study describes the national interRAI-HC population, assesses its data quality and evaluates its ability to be matched. Methods: The interRAI-HC...
Article
Full-text available
Spatially balanced sampling is becoming a popular design for surveys in biological and environmental management. For large scale surveys, where the region of interest is too large to visit every site, a sample is taken from a selection of sites. The process used to select these sites is called the survey design. Spatially balanced designs ensure th...
Chapter
One of the features underpinning good quality environmental management is that it is based on reliable, accurate, and timely information. Statistics in environmental management is a key part of a good management system. The role of statistics in environmental management is to supply information on the ecosystem and the effects of human interactions...
Article
In this paper, we consider the best linear unbiased estimators (BLUEs) based on double ranked set sampling (DRSS) and ordered DRSS (ODRSS) schemes for the simple linear regression model with replicated observations. We assume three symmetric distributions for the random error term, i.e., normal, Laplace and some scale contaminated normal distributi...
Article
In environmental monitoring and assessment, the main focus is to achieve observational economy and to collect data with unbiased, efficient and cost-effective sampling methods. Ranked set sampling (RSS) is one traditional method that is mostly used for accomplishing observational economy. In this paper, we propose an unbiased sampling scheme, named...
Article
Decision trees are a popular technique in statistical data classification. They recursively partition the feature space into disjoint sub-regions until each sub-region becomes homogeneous with respect to a particular class. The basic Classification and Regression Tree (CART) algorithm partitions the feature space using axis parallel splits. When th...
Article
Control charts are a powerful statistical process monitoring tool often used to monitor the stability of manufacturing processes. In quality control applications, measurement errors adversely affect the performance of control charts. In this paper, we study the effect of measurement error on the detection abilities of the exponentially weighted mov...
Article
In this paper, we propose a generalized ranked set sampling (RSS) scheme, namely, varied L-RSS (VLRSS) for estimating the population mean. VLRSS scheme encompasses several existing RSS schemes and helps in selecting more representative samples from the target population. It is shown that, for a symmetric population, the mean estimator under VLRSS s...
Article
Abstact: In this paper, we propose best linear unbiased estimators (BLUEs) and best linear invariant estimators (BLIEs) for the unknown parameters of location-scale family of distributions based on double ranked set sampling (DRSS) using perfect and imperfect rankings. These estimators are then compared with the BLUEs and BLIEs based on ranked set...
Article
A control chart is a powerful statistical process monitoring tool that is frequently used in many industrial and service organizations to monitor in-control and out-of-control performances of the manufacturing processes. Cumulative sum (CUSUM) and exponentially weighted moving average (EWMA) control charts have been recognized as potentially powerf...
Article
Adaptive cluster sampling can be a useful design for surveying rare and clustered populations. Here we present a new development in adaptive cluster sampling where we use a two-stage design and extend the complete allocation sampling method. In the proposed new design the primary sample units are selected and, depending on the value of a preset con...
Article
Exponentially weighted moving average (EWMA) control charts have been widely recognized as a potentially powerful process monitoring tool of the statistical process control because of their excellent speed in detecting small to moderate shifts in the process parameters. Recently, new EWMA and synthetic control charts have been proposed based on the...
Article
Exponentially weighted moving average (EWMA) and cumulative sum (CUSUM) control charts are potentially powerful statistical process monitoring tools because of their excellent speed in detecting small to moderate persistent process shifts. Recently, synthetic EWMA (SynEWMA) and synthetic CUSUM (SynCUSUM) control charts have been proposed based on s...
Article
Balakrishnan and Li (2005) introduced the use of ordered ranked set sampling (ORSS) and derived the best linear unbiased estimators (BLUEs) under ORSS (BLUEs-ORSS). In this study, we extend the work to ordered double ranked set sampling (ODRSS) scheme by using the idea of order statistics from independent and nonidentically distributed random varia...
Article
A statistical quality control chart is widely recognized as a potentially powerful tool that is frequently used in many manufacturing and service industries to monitor the quality of the product or manufacturing processes. In this paper, we propose new synthetic control charts for monitoring the process mean and the process dispersion. The proposed...
Article
Maximum exponentially weighted moving average (MaxEWMA) control charts have attracted substantial interest because of their ability to simultaneously detect increases and decreases in both the process mean and the process variability. In this paper, we propose new MaxEWMA control charts based on ordered double ranked set sampling (ODRSS) and ordere...
Article
Exponentially weighted moving average (EWMA) quality control schemes have been recognized as a potentially powerful process monitoring tool because of their superior speed in detecting small to moderate shifts in the underlying process parameters. In quality control literature, there exist several EWMA charts that are based on simple random samplin...
Article
Exponentially weighted moving average (EWMA) and cumulative sum (CUSUM) control charts have found extensive applications in industry. The sensitivity of these quality control schemes can be increased by using fast initial response (FIR) features. In this paper, we introduce some improved FIR features for EWMA and CUSUM control charts and evaluate t...
Article
Exponentially weighted moving average (EWMA) control charts have been widely recognized as a potentially powerful process monitoring tool of the statistical process control because of their excellent speed in detecting small to moderate shifts in the process parameters. Recently, new EWMA and synthetic control charts have been proposed based on the...
Article
Cost-effective sampling methods are of major concern in surveys of natural resources in agriculture, biology, ecology, forestry, fisheries, environmental management, etc. In this paper, we propose a hybrid ranked set sampling (HRSS) scheme for estimation of the population mean. The proposed sampling scheme encompasses several existing ranked set sa...
Article
Exponentially weighted moving average (EWMA) control charts have been widely accepted because of their excellent performance in detecting small to moderate shifts in the process parameters. In this paper, we propose new EWMA control charts for monitoring the process mean and the process dispersion. These EWMA control charts are based on the best li...
Article
The main focus of agricultural, ecological and environmental studies is to develop well designed, cost-effective and efficient sampling designs. Ranked set sampling (RSS) is one method that leads to accomplish such objectives by incorporating expert knowledge to its advantage. In this paper, we propose an efficient sampling scheme, named mixed RSS...
Article
Models based on species distributions are widely used and serve important purposes in ecology, biogeography and conservation. Their continuous predictions of environmental suitability are commonly converted into a binary classification of predicted (or potential) presences and absences, whose accuracy is then evaluated through a number of measures...
Article
Maximum exponentially weighted moving average (MaxEWMA) control charts have gained considerable attention for detecting changes in both process mean and process variability. In this paper, we propose an improved MaxEWMA control charts based on ordered ranked set sampling (ORSS) and ordered imperfect ranked set sampling (OIRSS) schemes for simultane...
Article
Full-text available
Throughout the world, the invasion of nonnative plants is an increasing threat to native biodiversity and ecosystem sustainability. Invasion is especially prevalent in areas affected by land transformation and disturbance. Surface mines are a major land transformation, and thus may promote the establishment and persistence of invasive plant communi...
Article
Exponentially weighted moving average (EWMA) control charts are mostly used to monitor the manufacturing processes. In this paper, we propose some improved EWMA control charts for detecting the random shifts in the process mean and process dispersion. These EWMA control charts are based on the best linear unbiased estimators obtained under ordered...
Article
To design an efficient survey or monitoring program for a natural resource it is important to consider the spatial distribution of the resource. Generally, sample designs that are spatially balanced are more efficient than designs which are not. A spatially balanced design selects a sample that is evenly distributed over the extent of the resource....
Article
Exponentially weighted moving average (EWMA) control charts have received considerable attention for detecting small changes in the process mean or the process variability. Several EWMA control charts are constructed using logarithmic and normalizing transformations on unbiased sample variance for monitoring changes in the process dispersion. In th...
Article
Full-text available
We extend the method of adaptive two-stage sequen-tial sampling to include designs where there is more than one crite-ria used in deciding on the allocation of additional sampling effort. These criteria, or conditions, can be a measure of the target popula-tion, or a measure of some related population. We develop Murthy estimator for the design tha...
Article
We present the results of a simulation study into the properties of 12 different estimators of the Hurst parameter, H, or the fractional integration parameter, d, in long memory time series which are available in R packages. We compare and contrast their performance on simulated Fractional Gaussian Noises and fractionally integrated series with len...
Article
Designing an efficient large-area survey is a challenge, especially in environmental science when many populations are rare and clustered. Adaptive and unequal probability sampling designs are appealing when populations are rare and clustered because survey effort can be targeted to subareas of high interest. For example, higher density subareas ar...
Article
In some adaptive sampling designs, expectations need to be calculated as sampling progresses. For situations when these calculations need to be done in the field where there is no acce ss to computers, or for very complicated and computer intensive calculations, we introduce an approximation method. The method to approximate the expectation is base...
Article
We discuss a major change in the way we teach our first-year statistics course. We have redesigned this course with emphasis on teaching critical thinking. We recognized that most of the students take the course for general knowledge and support of other majors, and very few are planning to major in statistics. We identified the essential aspects o...
Article
Full-text available
Distribution models of invasive plants are very useful tools for conservation management. There are challenges in modeling expanding populations, especially in a dynamic environment, and when data are limited. In this paper, predictive habitat models were assessed for three invasive plant species, at differing levels of occurrence, using two differ...
Article
Full-text available
The endemic Pyrenean Desman (Galemys pyrenaicus) is an elusive, rare, and vulnerable species declining over its entire and narrow range (Spain, Portugal, France, and Andorra). The principal set of conservation measures in France is a 5-years National Action Plan based on 25 conservation actions. Priority is given to update its present distribution...
Article
Full-text available
Throughout the world, the invasion of alien plants is an increasing threat to native biodiversity. Invasion is especially prevalent in areas affected by land transformation and anthropogenic disturbance. Surface mines are a major disturbance, and thus may promote the establishment and expansion of invasive plant communities. Environmental and habit...
Conference Paper
Full-text available
Assessing populations of rare species is challenging because of the large effort required to locate patches of occupied habitat and achieve precise estimates of density and abundance. The presence of a rare species has been shown to be correlated with presence or abundance of more common species. Thus, ecological community richness or abundance can...
Article
The fate of arsenic introduced to the environment as a result of the natural and human activities is an important issue. Surveys of arsenic typically involve sampling from a large area. Measuring arsenic concentrations in samples is expensive, and any improvement in the survey design is welcome. One way to improve efficiency in sampling is to make...
Article
Full-text available
Ever since H.E. Hurst brought the concept of long memory time series to prominence in his study of river flows the origins of the so-called Hurst phenomena have remained elusive. Two sets of competing models have been proposed. The fractional Gaussian noises and their discrete time counter-part, the fractionally integrated processes, possess genuin...
Article
Predicting the potential distribution of invasive plants within a specific region is pivotal to planning effective management but is challenged by attempting to model expanding populations that are rarely at equilibrium with their environment. We adopt an ensemble modelling approach to assess the potential distribution of Japanese honeysuckle (Loni...
Article
In the literature many papers state that long-memory time series models such as Fractional Gaussian Noises (FGN) or Fractionally Integrated series (FI(d)) are empirically indistinguishable from models with a non-stationary mean, but which are mean reverting. We present an analysis of the statistical cost of model mis-specification when simulated lo...
Article
Full-text available
Designing an efficient large-area survey is a challenge, especially in environmental science when many populations are rare and clustered. Adaptive and unequal probability sampling designs are appealing when populations are rare and clustered because survey effort can be targeted to subareas of high interest. For example, higher density subareas ar...
Article
Full-text available
In stratified sampling, methods for the allocation of effort among strata usually rely on some measure of within-stratum variance. If we do not have enough information about these variances, adaptive allocation can be used. In adaptive allocation designs, surveys are conducted in two phases. Information from the first phase is used to allocate the...
Article
Full-text available
In this article we present a computationally efficient method for finding 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 find the tree-based method...
Article
Adaptive sampling designs are becoming increasingly popular in environmental science, particularly for surveying rare and aggregated populations. An adaptive sample is one in which the survey design is modified, or adapted, in some way on the basis of information gained during the survey. There are many different adaptive survey designs that can be...
Article
Full-text available
This research explores the integration of GIS and remote sensing with statistical analysis to assist in species distribution modeling of invasive species. It is applicable to both native and non-native species and has the ability to assist land managers in identifying both areas of importance and areas of threat.
Article
Full-text available
As our impact on the landscape changes the composition of 'natural' areas, it is important that we integrate geospatial technology to assist in active management. This research explores the integration of GIS and remote sensing to assist in species habitat mapping. It is applicable to both native and non-native communities and has the ability to as...
Article
Abstract Surveying species that are present in low numbers is difficult because often the survey fails to locate any individuals. One strategy to improve the sample design is to survey the site repeatedly. With repeat surveys the abundance of the target species, and hence likelihood of detection, may change between visits. We present a model for de...
Article
Full-text available
We present the results of a simulation study into the properties of 12 different estimators of the Hurst parameter, $H$, or the fractional integration parameter, $d$, in long memory time series. We compare and contrast their performance on simulated Fractional Gaussian Noises and fractionally integrated series with lengths between 100 and 10,000 da...
Article
When estimating a true population parameter from survey data, there is always some level of uncertainty as a result of imperfect detection, imperfect observation, spatial and temporal variation, and sampling error. In this report, we discuss the sources of uncertainty in New Zealand braided river bird counts. We use Monte Carlo simulations to illus...