1,303 research outputs found
South Dakota\u27s Big Sioux and Vermillion River Basins: Economic Value of Irrigation Water
The primary objective of this study was to estimate the value of water used for irrigation in the Big Sioux and Vermillion river basins of eastern South Dakota. These estimates were made by imputing a residual value of water. Data were acquired through personal interviews with irrigators in the study area which was partitioned into two rainfall regions and two soil areas per rainfall region. Crop enterprise budgets were derived from the data and used to calculate net returns to management and water. These figures were compared with net returns to management from dryland farming obtained from secondary sources to arrive at the final water value estimates
Minkowski compactness measure
This is the author accepted manuscript. The final version is available from the publisher via the DOI in this record.Published in: Computational Intelligence (UKCI), 2013, 13th UK Workshop, Guildford UK.
Date of Conference: 9-11 Sept. 2013Many compactness measures are available in the
literature. In this paper we present a generalised compactness
measure Cq(S) which unifies previously existing definitions of
compactness. The new measure is based on Minkowski distances
and incorporates a parameter q which modifies the behaviour of
the compactness measure. Different shapes are considered to be
most compact depending on the value of q: for q = 2, the most
compact shape in 2D (3D) is a circle (a sphere); for q → ∞,
the most compact shape is a square (a cube); and for q = 1, the
most compact shape is a square (a octahedron).
For a given shape S, measure Cq(S) can be understood as a
function of q and as such it is possible to calculate a spectum of
Cq(S) for a range of q. This produces a particular compactness
signature for the shape S, which provides additional shape
information.
The experiments section of this paper provides illustrative
examples where measure Cq(S) is applied to various shapes and
describes how measure and its spectrum can be used for image
processing applications
The Bayesian Decision Tree Technique with a Sweeping Strategy
The uncertainty of classification outcomes is of crucial importance for many
safety critical applications including, for example, medical diagnostics. In
such applications the uncertainty of classification can be reliably estimated
within a Bayesian model averaging technique that allows the use of prior
information. Decision Tree (DT) classification models used within such a
technique gives experts additional information by making this classification
scheme observable. The use of the Markov Chain Monte Carlo (MCMC) methodology
of stochastic sampling makes the Bayesian DT technique feasible to perform.
However, in practice, the MCMC technique may become stuck in a particular DT
which is far away from a region with a maximal posterior. Sampling such DTs
causes bias in the posterior estimates, and as a result the evaluation of
classification uncertainty may be incorrect. In a particular case, the negative
effect of such sampling may be reduced by giving additional prior information
on the shape of DTs. In this paper we describe a new approach based on sweeping
the DTs without additional priors on the favorite shape of DTs. The
performances of Bayesian DT techniques with the standard and sweeping
strategies are compared on a synthetic data as well as on real datasets.
Quantitatively evaluating the uncertainty in terms of entropy of class
posterior probabilities, we found that the sweeping strategy is superior to the
standard strategy
Optimising decision trees using multi-objective particle swarm optimisation
Copyright © 2009 Springer-Verlag Berlin Heidelberg. The final publication is available at link.springer.comBook title: Swarm Intelligence for Multi-objective Problems in Data MiningSummary.
Although conceptually quite simple, decision trees are still among the most popular classifiers applied to real-world problems. Their popularity is due to a number of factors – core among these is their ease of comprehension, robust performance and fast data processing capabilities. Additionally feature selection is implicit within the decision tree structure.
This chapter introduces the basic ideas behind decision trees, focusing on decision trees which only consider a rule relating to a single feature at a node (therefore making recursive axis-parallel slices in feature space to form their classification boundaries). The use of particle swarm optimization (PSO) to train near optimal decision trees is discussed, and PSO is applied both in a single objective formulation (minimizing misclassification cost), and multi-objective formulation (trading off misclassification rates across classes).
Empirical results are presented on popular classification data sets from the well-known UCI machine learning repository, and PSO is demonstrated as being fully capable of acting as an optimizer for trees on these problems. Results additionally support the argument that multi-objectification of a problem can improve uni-objective search in classification problems
SRB Environment Evaluation and Analysis. Volume 3: ASRB Plume Induced Environments
Contract NAS8-37891 was expanded in late 1989 to initiate analysis of Shuttle plume induced environments as a result of the substitution of the Advanced Solid Rocket Booster (ASRB) for the Redesigned Solid Rocket Booster (RSRB). To support this analysis, REMTECH became involved in subscale and full-scale solid rocket motor test programs which further expanded the scope of work. Later contract modifications included additional tasks to produce initial design cycle environments and to specify development flight instrumentation. Volume 3 of the final report describes these analyses and contains a summary of reports resulting from various studies
Pigmentary keratitis in pugs in the United Kingdom: prevalence and associated features
BACKGROUND: Pigmentary keratitis (PK) is commonly recognised in Pugs, but its aetiology is not completely understood. The aim of this study was to determine the prevalence and associated features of PK in Pugs in the United Kingdom (UK). RESULTS: A total of 210 Pugs (420 eyes) were recruited from 12 UK dog shows and social events. The median age of Pugs recruited was 2.50 years (range 0.25-16.25 years). Pigmentary keratitis was detected in 369/420 (87.8%) eyes and in at least one eye 193/210 (91.9%) Pugs, of which 17/193 (8.8%) were affected unilaterally and 176/193 (91.2%) bilaterally. Pigmentary keratitis was typically mild to moderate (46.3 and 49.9% of eyes, respectively). Detection of PK was significantly associated with increased age (P = 0.002) and the presence of medial entropion of the lower eyelid (MELE) (P = 0.001). Severity of PK was significantly associated with the grade of MELE (P < 0.001). There was also a correlation between the presence of limbal pigment and PK (P = 0.036) that warrants further study. CONCLUSIONS: This study estimated a high disease prevalence of PK in UK Pugs, and demonstrated significant associations with age and the presence of MELE. These associations, which have not been previously reported, offer an insight into the underlying pathophysiology of this condition in Pugs. The results encourage further population research, such as prospective longitudinal studies. These findings also support the development of clinical and breeding strategies based on the reduction of MELE and, possibly, limbal pigment.</p
Integrating the promotion of physical activity within a smoking cessation programme: Findings from collaborative action research in UK Stop Smoking Services
Background: Within the framework of collaborative action research, the aim was to explore the feasibility of
developing and embedding physical activity promotion as a smoking cessation aid within UK 6/7-week National
Health Service (NHS) Stop Smoking Services.
Methods: In Phase 1 three initial cycles of collaborative action research (observation, reflection, planning,
implementation and re-evaluation), in an urban Stop Smoking Service, led to the development of an integrated
intervention in which physical activity was promoted as a cessation aid, with the support of a theoretically based
self-help guide, and self monitoring using pedometers. In Phase 2 advisors underwent training and offered the
intervention, and changes in physical activity promoting behaviour and beliefs were monitored. Also, changes in
clients’ stage of readiness to use physical activity as a cessation aid, physical activity beliefs and behaviour and
physical activity levels were assessed, among those who attended the clinic at 4-week post-quit. Qualitative data
were collected, in the form of clinic observation, informal interviews with advisors and field notes.
Results: The integrated intervention emerged through cycles of collaboration as something quite different to
previous practice. Based on field notes, there were many positive elements associated with the integrated
intervention in Phase 2. Self-reported advisors’ physical activity promoting behaviour increased as a result of
training and adapting to the intervention. There was a significant advancement in clients’ stage of readiness to use physical activity as a smoking cessation aid.
Conclusions: Collaboration with advisors was key in ensuring that a feasible intervention was developed as an aid to smoking cessation. There is scope to further develop tailored support to increasing physical activity and
smoking cessation, mediated through changes in perceptions about the benefits of, and confidence to do physical activity
Systolic blood pressure reactions to acute stress are associated with future hypertension status in the Dutch Famine Birth Cohort Study
These analyses examined the association between blood pressure reactions to acute psychological stress and subsequent hypertension status in a substantial Dutch cohort. Blood pressure was recorded during a resting baseline and during three acute stress tasks, Stroop colour word, mirror tracing and speech. Five years later, diagnosed hypertension status was determined by questionnaire. Participants were 453 (237 women) members of the Dutch Famine Birth Cohort. In analysis adjusting for a number of potential confounders, systolic blood pressure reactivity was positively related to future hypertension. This was the case irrespective of whether reactivity was calculated as the peak or the average response to the stress tasks. The association was strongest for reactions to the speech and Stroop tasks. Diastolic blood pressure reactivity was not significantly associated with hypertension. The results provide support for the reactivity hypothesis. \ud
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Spectral Templates from Multicolor Redshift Surveys
Understanding how the physical properties of galaxies (e.g. their spectral
type or age) evolve as a function of redshift relies on having an accurate
representation of galaxy spectral energy distributions. While it has been known
for some time that galaxy spectra can be reconstructed from a handful of
orthogonal basis templates, the underlying basis is poorly constrained. The
limiting factor has been the lack of large samples of galaxies (covering a wide
range in spectral type) with high signal-to-noise spectrophotometric
observations. To alleviate this problem we introduce here a new technique for
reconstructing galaxy spectral energy distributions directly from samples of
galaxies with broadband photometric data and spectroscopic redshifts.
Exploiting the statistical approach of the Karhunen-Loeve expansion, our
iterative training procedure increasingly improves the eigenbasis, so that it
provides better agreement with the photometry. We demonstrate the utility of
this approach by applying these improved spectral energy distributions to the
estimation of photometric redshifts for the HDF sample of galaxies. We find
that in a small number of iterations the dispersion in the photometric
redshifts estimator (a comparison between predicted and measured redshifts) can
decrease by up to a factor of 2.Comment: 25 pages, 9 figures, LaTeX AASTeX, accepted for publication in A
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