9,978 research outputs found
Tandem aza-Claisen rearrangement and ring closing metathesis reactions: the stereoselective synthesis of functionalised carbocyclic amides
A one-pot, tandem process has been developed for the efficient synthesis of functionalised carbocyclic amides. A substituted cyclopentenyl trichloroacetamide was synthesised using a tandem thermal aza-Claisen rearrangement and RCM process, while an analogous cyclohexenyl trichloroacetamide was generated with high diastereoselectivity using a tandem MOM-ether directed metal-catalysed aza-Claisen rearrangement and RCM process
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RGFGA: An efficient representation and crossover for grouping genetic algorithms
There is substantial research into genetic algorithms that are used to group large numbers of
objects into mutually exclusive subsets based upon some fitness function. However, nearly all
methods involve degeneracy to some degree.
We introduce a new representation for grouping genetic algorithms, the restricted growth function
genetic algorithm, that effectively removes all degeneracy, resulting in a more efficient search. A new crossover operator is also described that exploits a measure of similarity between chromosomes in a population. Using several synthetic datasets, we compare the performance of our representation and crossover with another well known state-of-the-art GA method, a strawman
optimisation method and a well-established statistical clustering algorithm, with encouraging results
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Variable grouping in multivariate time series via correlation
The decomposition of high-dimensional multivariate time series (MTS) into a number of low-dimensional MTS is a useful but challenging task because the number of possible dependencies between variables is likely to be huge. This paper is about a systematic study of the “variable groupings” problem in MTS. In particular, we investigate different methods of utilizing the information regarding correlations among MTS variables. This type of method does not appear to have been studied before. In all, 15 methods are suggested and applied to six datasets where there are identifiable mixed groupings of MTS variables. This paper describes the general methodology, reports extensive experimental results, and concludes with useful insights on the strength and weakness of this type of grouping metho
Python for teaching introductory programming: A quantitative evaluation
This paper compares two different approaches of teaching introductory programming by quantitatively analysing the student assessments in a real classroom. The first approach is to emphasise the principles of object-oriented programming and design using Java from the very beginning. The second approach is to first teach the basic programming concepts (loops, branch, and use of libraries) using Python and then move on to oriented programming using Java. Each approach was adopted for one academic year (2008-09 and 2009-10) with first year undergraduate students. Quantitative analysis of the student assessments from the first semester of each year was then carried out. The results of this analysis are presented in this paper. These results suggest that the later approach leads to enhanced learning of introductory programming concepts by students
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ICARUS: Intelligent coupon allocation for retailers using search
Many retailers run loyalty card schemes for their customers offering incentives in the form of money off coupons. The total value of the coupons depends on how much the customer has spent. This paper deals with the problem of finding the smallest set of coupons such that each possible total can be represented as the sum of a pre-defined number of coupons. A mathematical analysis of the problem leads to the development of a genetic algorithm solution. The algorithm is applied to real world data using several crossover operators and compared to well known straw-person methods. Results are promising showing that considerable time can be saved by using this method, reducing a few days worth of consultancy time to a few minutes of computation
Dynamics of an experimental two bladed horizontal axis wind turbine with blade cyclic pitch variation
The turbine under study incorporates the combination of two features: the application of blade cyclic pitch variation; and the use of yaw angle control for rotor speed and torque regulation. Due to its emasculation by passive cyclic pitch variation the rotor can be rapidly yawed without encountering gyroscopic and aerodynamic hub moments and without noticeable out of plane excursions. The two bladed upwind rotor is vane stabilized and of very simple and rugged design. The principle was first checked out with a small scale wind tunnel model and then tested in the atmosphere with a 7.6 meter diameter experimental fully instrumented wind turbine driving a 3 phase alternator. The test results are summarized with respect to structural dynamics and yaw dynamics
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The detection and classification of blast cell in Leukaemia Acute Promyelocytic Leukaemia (AML M3) blood using simulated annealing and neural networks
This paper was delivered at AIME 2011: 13th Conference on Artifical Intelligence in Medicine.This paper presents a method for the detection and classification of blast cells in M3 with others sub-types using simulated annealing and neural networks. In this paper, we increased our test result from 10 images to 20 images. We performed Hill Climbing, Simulated Annealing and Genetic Algorithms for detecting the blast cells. As a result, simulated annealing is the “best” heuristic search for detecting the leukaemia cells. From the detection, we performed features extraction on the blast cells and we classifying based on M3 and other sub-types using neural networks. We received convincing result which has targeting around 97% in classifying of M3 with other sub-types. Our results are based on real world image data from a Haematology Department.Universiti Sains Islam Malaysia and the Ministry of Higher Education, Malaysi
A Review and Meta-Analysis of Age-Based Stereotype Threat: Negative Stereotypes, Not Facts, Do the Damage.
Stereotype threat effects arise when an individual feels at risk of confirming a negative stereotype about their group and consequently underperforms on stereotype relevant tasks (Steele, 2010). Among older people, underperformance across cognitive and physical tasks is hypothesized to result from age-based stereotype threat (ABST) because of negative age-stereotypes regarding older adults’ competence. The present review and meta-analyses examine 22 published and 10 unpublished articles, including 82 effect sizes (N = 3882) investigating ABST on older people’s (Mage = 69.5) performance. The analysis revealed a significant small-to-medium effect of ABST (d = .28) and important moderators of the effect size. Specifically, older adults are more vulnerable to ABST when (a) stereotype-based rather than fact-based manipulations are used (d = .52); (b) when performance is tested using cognitive measures (d = .36); and (c) occurs reliably when the dependent variable is measured proximally to the manipulation. The review raises important theoretical and methodological issues, and areas for future research. (PsycINFO Database Record (c) 2015 APA, all rights reserved
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