1000 resultados para Attribute Reduction


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R. Jensen and Q. Shen, 'Fuzzy-Rough Attribute Reduction with Application to Web Categorization,' Fuzzy Sets and Systems, vol. 141, no. 3, pp. 469-485, 2004.

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Learning disability (LD) is a neurological condition that affects a child’s brain and impairs his ability to carry out one or many specific tasks. LD affects about 10% of children enrolled in schools. There is no cure for learning disabilities and they are lifelong. The problems of children with specific learning disabilities have been a cause of concern to parents and teachers for some time. Just as there are many different types of LDs, there are a variety of tests that may be done to pinpoint the problem The information gained from an evaluation is crucial for finding out how the parents and the school authorities can provide the best possible learning environment for child. This paper proposes a new approach in artificial neural network (ANN) for identifying LD in children at early stages so as to solve the problems faced by them and to get the benefits to the students, their parents and school authorities. In this study, we propose a closest fit algorithm data preprocessing with ANN classification to handle missing attribute values. This algorithm imputes the missing values in the preprocessing stage. Ignoring of missing attribute values is a common trend in all classifying algorithms. But, in this paper, we use an algorithm in a systematic approach for classification, which gives a satisfactory result in the prediction of LD. It acts as a tool for predicting the LD accurately, and good information of the child is made available to the concerned

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There are limitations in recent research undertaken on attribute reduction in incomplete decision systems. In this paper, we propose a distance-based method for attribute reduction in an incomplete decision system. In addition, we prove theoretically that our method is more effective than some other methods.

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A rough set approach for attribute reduction is an important research subject in data mining and machine learning. However, most attribute reduction methods are performed on a complete decision system table. In this paper, we propose methods for attribute reduction in static incomplete decision systems and dynamic incomplete decision systems with dynamically-increasing and decreasing conditional attributes. Our methods use generalized discernibility matrix and function in tolerance-based rough sets.

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X. Wang, J. Yang, R. Jensen and X. Liu, 'Rough Set Feature Selection and Rule Induction for Prediction of Malignancy Degree in Brain Glioma,' Computer Methods and Programs in Biomedicine, vol. 83, no. 2, pp. 147-156, 2006.

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Rough Set Data Analysis (RSDA) is a non-invasive data analysis approach that solely relies on the data to find patterns and decision rules. Despite its noninvasive approach and ability to generate human readable rules, classical RSDA has not been successfully used in commercial data mining and rule generating engines. The reason is its scalability. Classical RSDA slows down a great deal with the larger data sets and takes much longer times to generate the rules. This research is aimed to address the issue of scalability in rough sets by improving the performance of the attribute reduction step of the classical RSDA - which is the root cause of its slow performance. We propose to move the entire attribute reduction process into the database. We defined a new schema to store the initial data set. We then defined SOL queries on this new schema to find the attribute reducts correctly and faster than the traditional RSDA approach. We tested our technique on two typical data sets and compared our results with the traditional RSDA approach for attribute reduction. In the end we also highlighted some of the issues with our proposed approach which could lead to future research.

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Learning Disability (LD) is a neurological condition that affects a child’s brain and impairs his ability to carry out one or many specific tasks. LD affects about 15 % of children enrolled in schools. The prediction of LD is a vital and intricate job. The aim of this paper is to design an effective and powerful tool, using the two intelligent methods viz., Artificial Neural Network and Adaptive Neuro-Fuzzy Inference System, for measuring the percentage of LD that affected in school-age children. In this study, we are proposing some soft computing methods in data preprocessing for improving the accuracy of the tool as well as the classifier. The data preprocessing is performed through Principal Component Analysis for attribute reduction and closest fit algorithm is used for imputing missing values. The main idea in developing the LD prediction tool is not only to predict the LD present in children but also to measure its percentage along with its class like low or minor or major. The system is implemented in Mathworks Software MatLab 7.10. The results obtained from this study have illustrated that the designed prediction system or tool is capable of measuring the LD effectively

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The amount of textual information digitally stored is growing every day. However, our capability of processing and analyzing that information is not growing at the same pace. To overcome this limitation, it is important to develop semiautomatic processes to extract relevant knowledge from textual information, such as the text mining process. One of the main and most expensive stages of the text mining process is the text pre-processing stage, where the unstructured text should be transformed to structured format such as an attribute-value table. The stemming process, i.e. linguistics normalization, is usually used to find the attributes of this table. However, the stemming process is strongly dependent on the language in which the original textual information is given. Furthermore, for most languages, the stemming algorithms proposed in the literature are computationally expensive. In this work, several improvements of the well know Porter stemming algorithm for the Portuguese language, which explore the characteristics of this language, are proposed. Experimental results show that the proposed algorithm executes in far less time without affecting the quality of the generated stems.

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R. Jensen and Q. Shen. Fuzzy-Rough Sets Assisted Attribute Selection. IEEE Transactions on Fuzzy Systems, vol. 15, no. 1, pp. 73-89, 2007.

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This paper applies an attribute-based stated choice experiment approach to estimate the value that society places on changes to the size of the badger population in England and Wales. The study was undertaken in the context of a rising incidence of bovine tuberculosis (bTB) in cattle and the government's review of current bTB control policy. This review includes consideration of culling badgers to reduce bTB in cattle, since badgers are thought to be an important wildlife reservoir for the disease. The design of the CE involved four attributes (size of badger population, cattle slaughtered due to bTB, badger management strategy and household tax) at four levels with eight choice sets of two alternatives presented to respondents. Telephone interviews were undertaken with over 400 respondents, which elicited their attitudes and preferences concerning badgers, bTB in cattle and badger management strategies. The study estimated a willingness to pay of 0.10 pound per household per year per 100,000 badgers and 1.52 pound per household per year per 10,000 cattle slaughtered due to bTB which aggregated to 22 per badger and 3298 pound per bTB slaughtered animal for all households in England and Wales. Management strategy toward badgers had a very high valuation, highlighting the emotive issue of badger culling for respondents and the importance of government policy towards badgers.

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Esta tesis estudia la reducción plena (‘full reduction’ en inglés) en distintos cálculos lambda. 1 En esencia, la reducción plena consiste en evaluar los cuerpos de las funciones en los lenguajes de programación funcional con ligaduras. Se toma el cálculo lambda clásico (i.e., puro y sin tipos) como el sistema formal que modela el paradigma de programación funcional. La reducción plena es una técnica fundamental cuando se considera a los programas como datos, por ejemplo para la optimización de programas mediante evaluación parcial, o cuando algún atributo del programa se representa a su vez por un programa, como el tipo en los demostradores automáticos de teoremas actuales. Muchas semánticas operacionales que realizan reducción plena tienen naturaleza híbrida. Se introduce formalmente la noción de naturaleza híbrida, que constituye el hilo conductor de todo el trabajo. En el cálculo lambda la naturaleza híbrida se manifiesta como una ‘distinción de fase’ en el tratamiento de las abstracciones, ya sean consideradas desde fuera o desde dentro de si mismas. Esta distinción de fase conlleva una estructura en capas en la que una semántica híbrida depende de una o más semánticas subsidiarias. Desde el punto de vista de los lenguajes de programación, la tesis muestra como derivar, mediante técnicas de transformación de programas, implementaciones de semánticas operacionales que reducen plenamente a partir de sus especificaciones. Las técnicas de transformación de programas consisten en transformaciones sintácticas que preservan la equivalencia semántica de los programas. Se ajustan las técnicas de transformación de programas existentes para trabajar con implementaciones de semánticas híbridas. Además, se muestra el impacto que tiene la reducción plena en las implementaciones que utilizan entornos. Los entornos son un ingrediente fundamental en las implementaciones realistas de una máquina abstracta. Desde el punto de vista de los sistemas formales, la tesis desvela una teoría novedosa para el cálculo lambda con paso por valor (‘call-by-value lambda calculus’ en inglés) que es consistente con la reducción plena. Dicha teoría induce una noción de equivalencia observacional que distingue más puntos que las teorías existentes para dicho cálculo. Esta contribución ayuda a establecer una ‘teoría estándar’ en el cálculo lambda con paso por valor que es análoga a la ‘teoría estándar’ del cálculo lambda clásico propugnada por Barendregt. Se presentan resultados de teoría de la demostración, y se sugiere como abordar el estudio de teoría de modelos. ABSTRACT This thesis studies full reduction in lambda calculi. In a nutshell, full reduction consists in evaluating the body of the functions in a functional programming language with binders. The classical (i.e., pure untyped) lambda calculus is set as the formal system that models the functional paradigm. Full reduction is a prominent technique when programs are treated as data objects, for instance when performing optimisations by partial evaluation, or when some attribute of the program is represented by a program itself, like the type in modern proof assistants. A notable feature of many full-reducing operational semantics is its hybrid nature, which is introduced and which constitutes the guiding theme of the thesis. In the lambda calculus, the hybrid nature amounts to a ‘phase distinction’ in the treatment of abstractions when considered either from outside or from inside themselves. This distinction entails a layered structure in which a hybrid semantics depends on one or more subsidiary semantics. From a programming languages standpoint, the thesis shows how to derive implementations of full-reducing operational semantics from their specifications, by using program transformations techniques. The program transformation techniques are syntactical transformations which preserve the semantic equivalence of programs. The existing program transformation techniques are adjusted to work with implementations of hybrid semantics. The thesis also shows how full reduction impacts the implementations that use the environment technique. The environment technique is a key ingredient of real-world implementations of abstract machines which helps to circumvent the issue with binders. From a formal systems standpoint, the thesis discloses a novel consistent theory for the call-by-value variant of the lambda calculus which accounts for full reduction. This novel theory entails a notion of observational equivalence which distinguishes more points than other existing theories for the call-by-value lambda calculus. This contribution helps to establish a ‘standard theory’ in that calculus which constitutes the analogous of the ‘standard theory’ advocated by Barendregt in the classical lambda calculus. Some prooftheoretical results are presented, and insights on the model-theoretical study are given.

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The dietary intake of sodium chloride has increased considerably over the last few decades due to changes in the human diet. This higher intake has been linked to a number of diseases including hypertension and other cardiovascular diseases. Numerous international health agencies, as well as the food industry, have now recommended a salt intake level of 5-6 g daily, approximately half of the average current daily intake level. Cereal products, and in particular bread, are a major source of salt in the Western diet. Therefore, any reduction in the level of salt in bread could have a major impact on global health. However, salt is a critical ingredient in bread production, and its reduction can have a deleterious effect on the production process as well as on the final bread quality characteristics such as shelf-life, bread volume and sensory characteristics, all deviating from the bakers’ and consumers’ expectations. This work addresses the feasibility of NaCl reduction in wheat bread focusing on options to compensate NaCl with the use of functional sourdoughs. Three strains were used for the application of low-salt bread; L. amylovorus DSM19280, W. cibaria MG1 and L. reuteri FF2hh2. The multifunctional strain L. reuteri FF2hh2 was tested the first time and its application could be demonstrated successfully. The functionalities were based on the production of exopolysaccharides as well as the production of antifungal compounds. While the exopolysaccharides, mainly high molecular dextrans, positively influenced mainly bread loaf volume, crumb structure and staling rate, the strains producing antifungal compounds prolonged the microbial shelf life significantly and compensated the lack of salt. The impact on the sensory characteristics of bread were evaluated by descriptive sensory evaluation. The increase in surface area as well as the presence of organic acids impacted significantly on the flavour profile of the sourdough bread samples. The flavour attribute “salt” could be enhanced by sourdough addition and increased the salty perception. Furthermore, a trained sensory panel evaluated for the first time the impact of yeast activity, based on different salt and yeast concentrations, on the volatile aroma profile of bread crumb samples. The analytical measurements using high resolution gas chromatography and proton-transfer-reaction mass spectrometry (PTR-MS) resulted in significantly different results based on different yeast activities. Nevertheless, the extent of the result could not be recognised by the sensory panel analysing the odour profile of the bread crumb samples. Hence, the consumer cannot recognised low-salt bread by its odour. The use of sourdough is a natural option to overcome the broad range of technological issues caused by salt reduction and also a more popular alternative compared to existing chemical salt replacers.

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The UK’s historically low cost of energy has encouraged a culture that considers energy to be in limitless supply and excessive levels of consumption acceptable. Now that supplies are becoming restricted and costs rising, it is becoming recognised this energy culture has created a legacy stock of buildings with poor building fabric, limited energy efficiency equipment and even lower levels of energy awareness. Cost effective technologies are readily available but not adopted by UK SMEs in non-domestic buildings, as rational economic theory would expect. Policy-makers attribute this to inaccessibility of information and investment and design policies accordingly. However, as escalation of demand continues an alternative driver of this paradox must exist. This research hypothesises that this is the ownership structures of non-domestic buildings. Tenure of business premises is found to prevent adoption of energy conservation opportunities; 64% of SME surveyed encountered barriers to energy efficiency related to building ownership. When increased pro rata to reflect the UK SME population, almost 2.5 million businesses appear unable to benefit from energy improvements.