Inducing safer oblique trees without costs

Decision tree induction has been widely studied and applied. In safety applications, such as determining whether a chemical process is safe or whether a person has a medical condition, the cost of misclassification in one of the classes is significantly higher than in the other class. Several authors have tackled this problem by developing cost-sensitive decision tree learning algorithms or have suggested ways of changing the distribution of training examples to bias the decision tree learning process so as to take account of costs. A prerequisite for applying such algorithms is the availability of costs of misclassification. Although this may be possible for some applications, obtaining reasonable estimates of costs of misclassification is not easy in the area of safety. This paper presents a new algorithm for applications where the cost of misclassifications cannot be quantified, although the cost of misclassification in one class is known to be significantly higher than in another class. The algorithm utilizes linear discriminant analysis to identify oblique relationships between continuous attributes and then carries out an appropriate modification to ensure that the resulting tree errs on the side of safety. The algorithm is evaluated with respect to one of the best known cost-sensitive algorithms (ICET), a well-known oblique decision tree algorithm (OC1) and an algorithm that utilizes robust linear programming

An intervention modelling experiment to change GP's intentions to implement evidence-based practice : using theory-based interventions to promote GP management of upper respiratory tract infection without prescribing antibiotics #2

Background: Psychological theories of behaviour may provide a framework to guide the design of interventions to change professional behaviour. Behaviour change interventions, designed using psychological theory and targeting important motivational beliefs, were experimentally evaluated for effects on the behavioural intention and simulated behaviour of GPs in the management of uncomplicated upper respiratory tract infection (URTI). Methods: The design was a 2 × 2 factorial randomised controlled trial. A postal questionnaire was developed based on three theories of human behaviour: Theory of Planned Behaviour; Social Cognitive Theory and Operant Learning Theory. The beliefs and attitudes of GPs regarding the management of URTI without antibiotics and rates of prescribing on eight patient scenarios were measured at baseline and post-intervention. Two theory-based interventions, a "graded task" with "action planning" and a "persuasive communication", were incorporated into the post-intervention questionnaire. Trial groups were compared using co-variate analyses. Results: Post-intervention questionnaires were returned for 340/397 (86%) GPs who responded to the baseline survey. Each intervention had a significant effect on its targeted behavioural belief: compared to those not receiving the intervention GPs completing Intervention 1 reported stronger self-efficacy scores (Beta = 1.41, 95% CI: 0.64 to 2.25) and GPs completing Intervention 2 had more positive anticipated consequences scores (Beta = 0.98, 95% CI = 0.46 to 1.98). Intervention 2 had a significant effect on intention (Beta = 0.90, 95% CI = 0.41 to 1.38) and simulated behaviour (Beta = 0.47, 95% CI = 0.19 to 0.74). Conclusion: GPs' intended management of URTI was significantly influenced by their confidence in their ability to manage URTI without antibiotics and the consequences they anticipated as a result of doing so. Two targeted behaviour change interventions differentially affected these beliefs. One intervention also significantly enhanced GPs' intentions not to prescribe antibiotics for URTI and resulted in lower rates of prescribing on patient scenarios compared to a control group. The theoretical frameworks utilised provide a scientific rationale for understanding how and why the interventions had these effects, improving the reproducibility and generalisability of these findings and offering a sound basis for an intervention in a "real world" trial. Trial registration: Clinicaltrials.gov NCT00376142This study is funded by the European Commission Research Directorate as part of a multi-partner program: Research Based Education and Quality Improvement (ReBEQI): A Framework and tools to develop effective quality improvement programs in European healthcare. (Proposal No: QLRT-2001-00657)

Μελέτη επί της τρισδιάστατης απεικόνισης και αυτόματης ανακατασκευής τρισδιάστατων προϊστορικών αγγείων

88 σ.Στην παρούσα διπλωματική εργασία γίνεται, αρχικά, μία αναφορά σε αρχές της θεωρίας των καμπυλών και επιφανειών της διαφορικής γεωμετρίας οι οποίες αποτελούν ένα απαραίτητο μαθηματικό υπόβαθρό της σχετικής προσέγγισης. Δίνεται έμφαση σε βασικές έννοιες, όπως της καμπύλης, της επιφάνειας αλλά και άλλων μεγεθών-εργαλείων που τις συνοδεύουν, ούτως ώστε να γίνει εφικτή η προσέγγιση στο θέμα της αυτόματης ανασυγκρότησης θραυσμάτων. Στην συνέχεια, ακολουθεί περιγραφή της επεξεργασίας, την οποία υπέστησαν τρισδιάστατες απεικονίσεις θραυσμάτων αγγείων, οι οποίες προέρχονται από την τρισδιάστατη σάρωση των πραγματικών θραυσμάτων με τρισδιάστατο σαρωτή. Η παραπάνω επεξεργασία αποτελεί προκαταρκτικό στάδιο για την εφαρμογή μίας νέας μεθόδου η οποία προσφέρει αποτελεσματική λύση στο πρόβλημα της αυτόματης εικονικής ανασυγκρότησης των θραυσμένων αγγείων για την οποία γίνεται αναφορά στη συνέχεια.In this thesis, initially, a report on principles of the theory of curves and surfaces, in differential geometry, takes place. These principles are the mathematical background of this thesis. The understanding of basic concepts such as curve , surface and other sizes–tools which surround them, is emphasized thanks to which the approach to automatic reconstruction of fragments is feasible. Then, follows a description of the processing that was applied in three-dimensional representations of broken vessels. These represantations derived from the three-dimensional scan of the real fragments with three-dimensional scanner. The above process is a preliminary step for the implementation of a new method which is an effective solution to the problem of automatic virtual reconstruction of broken vessels to which reference is made below.Ιωάννης Γ. Κοτζά

Índice de sustentabilidade agroambiental para o perímetro irrigado Ayres de Souza.

Uma análise integrada do atual uso dos recursos naturais do Perímetro Irrigado de Ayres de Souza, localizado no Vale do Acaraú, Ceará, foi realizada através do desenvolvimento de um índice de sustentabilidade agroecológica. Os dados dessa pesquisa foram oriundos de questionários aplicados a 33 produtores agrícolas beneficiados pelo projeto de irrigação. Os indicadores de sustentabilidade foram estimados pelo emprego de análise fatorial, método da análise fatorial/análise de componentes principais. O índice de sustentabilidade estimado a partir dos indicadores selecionados registrou uma situação de sustentabilidade fragilizada ou de insustentabilidade reversível. As unidades produtivas apresentaram um porcentual de 60,6% com alguma sustentabilidade; e os demais 39,4% estão em condições de insustentabilidade. Os resultados também mostraram que os fatores dominantes do índice de sustentabilidade foram: nível da atividade agrícola praticada, agricultura familiar, condições atuais do sistema água-solo e infraestrutura,fontes alternativas de renda e experiência em tratos culturais

Functional status of masticatory system, excutive function and episodic memory in older persons.

Findings from human experimental studies suggest that mastication positively influences cognitive function. The participants in those studies were relatively young. The goal of this study was to examine the relationship between the functional status of the masticatory system, episodic memory, and executive functions in elderly people. The participants, elderly people living independently at home, were divided into two groups. One group had a full complement of natural teeth (n = 19) and the other group had full dentures (n = 19). The functional status of the masticatory system was assessed by measuring mandibular excursions (i.e. the distances over which the mandible can move in the open, lateral, and forward directions), bite force, number of occluding pairs and complaints of the masticatory system (facial pain, headaches/migraine). Executive functions and episodic memory were assessed by neuropsychological tests. Backward regression analysis showed that only in the group of elderly people with full dentures, 22% of executive functions were predicted by complaints of the masticatory system and 19.4% of episodic memory was predicted by masticatory performance (composed of mandibular excursions and bite force). The conclusion of this study is that only in older persons with full dentures the relationship between mastication, episodic memory, and executive function becomes evident when the functional status of the masticatory system decreases

Exploring the constraint profile of winter sports resort tourist segments

Many studies have confirmed the importance of market segmentation both theoretically and empirically. Surprisingly though, no study has so far addressed the issue from the perspective of leisure constraints. Since different consumers face different barriers, we look at participation in leisure activities as an outcome of the negotiation process that winter sports resort tourists go through, to balance between related motives and constraints. This empirical study reports the findings on the applicability of constraining factors in segmenting the tourists who visit winter sports resorts. Utilizing data from 1,391 tourists of winter sports resorts in Greece, five segments were formed based on their constraint, demographic and behavioral profile. Our findings indicate that such segmentation sheds light on factors that could potentially limit the full utilization of the market. To maximize utilization, we suggest customizing marketing to the profile of each distinct winter sports resort tourist segment that emerge

Clustering cliques for graph-based summarization of the biomedical research literature

BACKGROUND: Graph-based notions are increasingly used in biomedical data mining and knowledge discovery tasks. In this paper, we present a clique-clustering method to automatically summarize graphs of semantic predications produced from PubMed citations (titles and abstracts). RESULTS: SemRep is used to extract semantic predications from the citations returned by a PubMed search. Cliques were identified from frequently occurring predications with highly connected arguments filtered by degree centrality. Themes contained in the summary were identified with a hierarchical clustering algorithm based on common arguments shared among cliques. The validity of the clusters in the summaries produced was compared to the Silhouette-generated baseline for cohesion, separation and overall validity. The theme labels were also compared to a reference standard produced with major MeSH headings. CONCLUSIONS: For 11 topics in the testing data set, the overall validity of clusters from the system summary was 10% better than the baseline (43% versus 33%). While compared to the reference standard from MeSH headings, the results for recall, precision and F-score were 0.64, 0.65, and 0.65 respectively