Merging Knowledge Bases in Possibilistic Logic by Lexicographic Aggregation

Belief merging is an important but difficult problem in Artificial Intelligence, especially when sources of information are pervaded with uncertainty. Many merging operators have been proposed to deal with this problem in possibilistic logic, a weighted logic which is powerful for handling inconsistency and deal-ing with uncertainty. They often result in a possibilistic knowledge base which is a set of weighted formulas. Although possibilistic logic is inconsistency tolerant, it suffers from the well-known "drowning effect". Therefore, we may still want to obtain a consistent possibilistic knowledge base as the result of merging. In such a case, we argue that it is not always necessary to keep weighted information after merging. In this paper, we define a merging operator that maps a set of possibilistic knowledge bases and a formula representing the integrity constraints to a classical knowledge base by using lexicographic ordering. We show that it satisfies nine postulates that generalize basic postulates for propositional merging given in [11]. These postulates capture the principle of minimal change in some sense. We then provide an algorithm for generating the resulting knowledge base of our merging operator. Finally, we discuss the compatibility of our merging operator with propositional merging and establish the advantage of our merging operator over existing semantic merging operators in the propositional case.

Design and Analysis of an Independent, Layer 2, Open-Access WiFi Monitoring Infrastructure in the Wild

While WiFi monitoring networks have been deployed in previous research, to date none have assessed live network data from an open access, public environment. In this paper we describe the construction of a replicable, independent WLAN monitoring system and address some of the challenges in analysing the resultant traffic. Analysis of traffic from the system demonstrates that basic traffic information from open-access networks varies over time (temporal inconsistency). The results also show that arbitrary selection of Request-Reply intervals can have a significant effect on Probe and Association frame exchange calculations, which can impact on the ability to detect flooding attacks.

Content validity of the Illness Perception Questionnaire-Revised for people with Type 2 Diabetes: A Think-Aloud study

Objectives: To access the cognitions of adults with type 2 diabetes whilst completing items on the Illness Perceptions Questionnaire – Revised (IPQ-R). To determine whether these cognitions are congruent with the meaning of items and subscales as interpreted by researchers and clinicians using the IPQ-R and to identify the nature and extent of problems that individuals experience when completing the IPQ-R.
Design: Participants (n=36) were recruited from a primary care diabetes clinic and a hospital diabetes clinic. They were asked to complete the IPQ-R using a ‘think-aloud’ methodology.
Main Outcome Measures: Transcripts were analysed to identify instances where participants expressed problems with item completion, or where there was inconsistency between verbal and written responses.
Results: The most problematic subscales were those of ‘personal control’ and ‘consequences’.
Conclusion: Generally, participants found the IPQ-R unproblematic. However, participants had problems with the concept of ‘cure’ and ‘symptoms’ in the context of type 2 diabetes, and with the negative phrasing used in some items. These findings have important implications for the interpretation of IPQ-R scores, particularly when the IPQ-R is used as the basis for individualised interventions among people with type 2 diabetes.

How Outcomes Are Defined in Clinical Trials of Mechanically Ventilated Adults and Children

Systematic reviews have considerable potential to provide evidence-based data to aid clinical decision-making. However, there is growing recognition that trials involving mechanical ventilation lack consistency in the definition and measurement of ventilation outcomes, creating difficulties in combining data for meta-analyses. To address the inconsistency in outcome definitions, international standards for trial registration and clinical trial protocols published recommendations, effectively setting the “gold standard” for reporting trial outcomes. In this Critical Care Perspective, we review the problems resulting from inconsistent outcome definitions and inconsistent reporting of outcomes (outcome sets). We present data highlighting the variability of the most commonly reported ventilation outcome definitions. Ventilation outcomes reported in trials over the last 6 years typically fall into four domains: measures of ventilator dependence; adverse outcomes; mortality; and resource use. We highlight the need, first, for agreement on outcome definitions and, second, for a minimum core outcome set for trials involving mechanical ventilation. A minimum core outcome set would not restrict trialists from measuring additional outcomes, but would overcome problems of variability in outcome selection, measurement, and reporting, thereby enhancing comparisons across trials.

Tools for Finding Inconsistencies in Real-world Logic-based Systems

Currently there is extensive theoretical work on inconsistencies in logic-based systems. Recently, algorithms for identifying inconsistent clauses in a single conjunctive formula have demonstrated that practical application of this work is possible. However, these algorithms have not been extended for full knowledge base systems and have not been applied to real-world knowledge. To address these issues, we propose a new algorithm for finding the inconsistencies in a knowledge base using existing algorithms for finding inconsistent clauses in a formula. An implementation of this algorithm is then presented as an automated tool for finding inconsistencies in a knowledge base and measuring the inconsistency of formulae. Finally, we look at a case study of a network security rule set for exploit detection (QRadar) and suggest how these automated tools can be applied.

On the Merit of Selecting Different Belief Merging Operators

Belief merging operators combine multiple belief bases (a profile) into a collective one. When the conjunction of belief bases is consistent, all the operators agree on the result. However, if the conjunction of belief bases is inconsistent, the results vary between operators. There is no formal manner to measure the results and decide on which operator to select. So, in this paper we propose to evaluate the result of merging operators by using three ordering relations (fairness, satisfaction and strength) over operators for a given profile. Moreover, a relation of conformity over operators is introduced in order to classify how well the operator conforms to the definition of a merging operator. By using the four proposed relations we provide a comparison of some classical merging operators and evaluate the results for some specific profiles.

Core Outcomes in Ventilation Trials (COVenT): protocol for a core outcome set using a Delphi survey with a nested randomised trial and observational cohort study

Background
Among clinical trials of interventions that aim to modify time spent on mechanical ventilation for critically ill patients there is considerable inconsistency in chosen outcomes and how they are measured. The Core Outcomes in Ventilation Trials (COVenT) study aims to develop a set of core outcomes for use in future ventilation trials in mechanically ventilated adults and children.

Methods/design
We will use a mixed methods approach that incorporates a randomised trial nested within a Delphi study and a consensus meeting. Additionally, we will conduct an observational cohort study to evaluate uptake of the core outcome set in published studies at 5 and 10 years following core outcome set publication. The three-round online Delphi study will use a list of outcomes that have been reported previously in a review of ventilation trials. The Delphi panel will include a range of stakeholder groups including patient support groups. The panel will be randomised to one of three feedback methods to assess the impact of the feedback mechanism on subsequent ranking of outcomes. A final consensus meeting will be held with stakeholder representatives to review outcomes.

Discussion
The COVenT study aims to develop a core outcome set for ventilation trials in critical care, explore the best Delphi feedback mechanism for achieving consensus and determine if participation increases use of the core outcome set in the long term.

Systematic Uncertainties Associated with the Cosmological Analysis of the First PAN-STARRS1 Type Ia Supernova Sample

We probe the systematic uncertainties from the 113 Type Ia supernovae (SN Ia) in the Pan-STARRS1 (PS1) sample along with 197 SN Ia from a combination of low-redshift surveys. The companion paper by Rest et al. describes the photometric measurements and cosmological inferences from the PS1 sample. The largest systematic uncertainty stems from the photometric calibration of the PS1 and low-z samples. We increase the sample of observed Calspec standards from 7 to 10 used to define the PS1 calibration system. The PS1 and SDSS-II calibration systems are compared and discrepancies up to ∼0.02 mag are recovered. We find uncertainties in the proper way to treat intrinsic colors and reddening produce differences in the recovered value of w up to 3%. We estimate masses of host galaxies of PS1 supernovae and detect an insignificant difference in distance residuals of the full sample of 0.037 ± 0.031 mag for host galaxies with high and low masses. Assuming flatness and including systematic uncertainties in our analysis of only SNe measurements, we find w = -1.120^+0.360_-0.206(Stat)^+0.269_-0.291(Sys). With additional constraints from Baryon acoustic oscillation, cosmic microwave background (CMB) (Planck) and H₀ measurements, we find w = -1.166^+0.072_-0.069 and Ω_m = 0.280^+0.013_-0.012 (statistical and systematic errors added in quadrature). The significance of the inconsistency with w = -1 depends on whether we use Planck or Wilkinson Microwave Anisotropy Probe measurements of the CMB: w_{BAO+H0+SN+WMAP} = -1.124^+0.083_-0.065.

Core outcome sets and trial registries

Some reasons for registering trials might be considered as self-serving, such as satisfying the requirements of a journal in which the researchers wish to publish their eventual findings or publicising the trial to boost recruitment. Registry entries also help others, including systematic reviewers, to know about ongoing or unpublished studies and contribute to reducing research waste by making it clear what studies are ongoing. Other sources of research waste include inconsistency in outcome measurement across trials in the same area, missing data on important outcomes from some trials, and selective reporting of outcomes. One way to reduce this waste is through the use of core outcome sets: standardised sets of outcomes for research in specific areas of health and social care. These do not restrict the outcomes that will be measured, but provide the minimum to include if a trial is to be of the most use to potential users. We propose that trial registries, such as ISRCTN, encourage researchers to note their use of a core outcome set in their entry. This will help people searching for trials and those worried about selective reporting in closed trials. Trial registries can facilitate these efforts to make new trials as useful as possible and reduce waste. The outcomes section in the entry could prompt the researcher to consider using a core outcome set and facilitate the specification of that core outcome set and its component outcomes through linking to the original core outcome set. In doing this, registries will contribute to the global effort to ensure that trials answer important uncertainties, can be brought together in systematic reviews, and better serve their ultimate aim of improving health and well-being through improving health and social care.

Survey of new 2007 and 2011 Cochrane reviews found 37% of prespecified outcomes not reported

OBJECTIVES: To survey the outcomes used in Cochrane Reviews, as part of our work within the Core Outcome Measures in Effectiveness Trials Initiative.

STUDY DESIGN AND SETTING: A descriptive survey of Cochrane Reviews, divided by Cochrane Review Group (CRG), published in full for the first time in 2007 and 2011. Outcomes specified in the methods section of each review and outcomes reported in the results section of each review were of interest, in this exploration of the common use of outcomes and core outcome sets (COS).

RESULTS: Seven hundred eighty-eight reviews, specifying 6,127 outcomes, were included. When we excluded specified outcomes from the 86 reviews that did not include any studies, we found that 1,996 (37%) specified outcomes were not reported. Of the 361 new reviews with studies from 2011, 113 (31%) had a "summary of findings" table (SoF). Fifteen broad outcome categories were identified and used to manage the outcome data. We found consistency in the use of these categories across CRGs but inconsistency in outcomes within these categories.

CONCLUSION: COS have been used rarely in Cochrane Reviews, but the introduction of SoF makes the development and application of COS timelier than ever.

Physical rehabilitation interventions for adult patients during critical illness: an overview of systematic reviews

Background Physical rehabilitation interventions aim to ameliorate the effects of critical illness-associated muscle dysfunction in survivors. We conducted an overview of systematic reviews (SR) evaluating the effect of these interventions across the continuum of recovery.

Methods Six electronic databases (Cochrane Library, CENTRAL, DARE, Medline, Embase, and Cinahl) were searched. Two review authors independently screened articles for eligibility and conducted data extraction and quality appraisal. Reporting quality was assessed and the Grading of Recommendations Assessment, Development and Evaluation approach applied to summarise overall quality of evidence.

Results Five eligible SR were included in this overview, of which three included meta-analyses. Reporting quality of the reviews was judged as medium to high. Two reviews reported moderate-to-high quality evidence of the beneficial effects of physical therapy commencing during intensive care unit (ICU) admission in improving critical illness polyneuropathy/myopathy, quality of life, mortality and healthcare utilisation. These interventions included early mobilisation, cycle ergometry and electrical muscle stimulation. Two reviews reported very low to low quality evidence of the beneficial effects of electrical muscle stimulation delivered in the ICU for improving muscle strength, muscle structure and critical illness polyneuropathy/myopathy. One review reported that due to a lack of good quality randomised controlled trials and inconsistency in measuring outcomes, there was insufficient evidence to support beneficial effects from physical rehabilitation delivered post-ICU discharge.

Conclusions Patients derive short-term benefits from physical rehabilitation delivered during ICU admission. Further robust trials of electrical muscle stimulation in the ICU and rehabilitation delivered following ICU discharge are needed to determine the long-term impact on patient care. This overview provides recommendations for design of future interventional trials and SR.

Práticas de produção de conhecimento: a investigação na formação de educadores de infância

Visando caracterizar formas de apropriação da realização de investigação na formação inicial de educadores de infância – dada a centralidade que a produção de conhecimento profissional específico assume para a profissão docente e para a qualidade do ensino – esta investigação procura identificar e gizar configurações curriculares de uma dimensão investigativa nos planos de estudo que sustentam a formação dos profissionais, cartografar conceções de professores e alunos sobre a relevância da realização de investigação durante a formação e para a profissão futura, assim como problematizar, através de uma análise metodológica, a produção investigativa realizada no âmbito da formação inicial, interpelando a relação entre propósitos formativos e percursos investigativos. Cada um destes objetivos foi concretizado num estudo, resultando em três estudos entrelaçados pela perspetiva interpretativa e quadro teórico que convocam e pelos diferentes contributos que projetam quer para o papel da investigação na formação inicial de professores quer para uma discussão mais ampla sobre a produção de conhecimento profissional específico. Os resultados são discutidos mobilizando o enquadramento conceptual que sustentou o estudo. A relevância da investigação no âmbito da formação inicial de professores, quer como processo de desenvolvimento de atitude crítica e processos de resolução de problemas quer como preparação para a produção de conhecimento profissional específico, surge nos três estudos embora com variações e ênfases distintas. A profissão como horizonte futuro, para os alunos, e como referência para a formação concebida, para os professores, revelouse um contexto preponderante na decisão e discussão sobre a produção de conhecimento na formação inicial. A variação de conceções e práticas encontrada ao longo dos três estudos, assim como a inconsistência intrainstituição detetada, sugerem que a discussão sobre como conceber e operacionalizar a realização de investigação por educadores de infância exige maior explicitação e maior tónica na especificidade, quer do conhecimento profissional docente quer da educação de infância no âmbito da profissão.

Children’s Friendships and Learning in School: Cognitive Enhancement Through Social Interaction?

Background. Recent literature has identified that children's performance on cognitive (or problem-solving) tasks can be enhanced when undertaken as a joint activity among pairs of pupils. Performance on this ‘social’ activity will require quality relationships between pupils, leading some researchers to argue that friendships are characterized by these quality relationships and, therefore, that friendship grouping should be used more frequently within classrooms. Aims. Children's friendship grouping may appear to be a reasonable basis for cognitive development in classrooms, although there is only inconsistent evidence to support this argument. The inconsistency may be explained by the various bases for friendship, and how friendship is affected by cultural contexts of gender and schooling. This study questions whether classroom-based friendship pairings will perform consistently better on a cognitive task than acquaintance pairings, taking into account gender, age, and ability level of children. The study also explores the nature of school-based friendship described by young children. Sample. 72 children were paired to undertake science reasoning tasks (SRTs). Pairings represented friendship (versus acquaintance), sex (male and female pairings), ability (teacher-assessed high, medium, and low), and age (children in Years 1, 3, and 5 in a primary school). Method. A small-scale quasi-experimental design was used to assess (friendship- or acquaintance-based) paired performance on SRTs. Friendship pairs were later interviewed about qualities and activities that characterized their friendships. Results. Girls' friendship pairings were found to perform at the highest SRT levels and boys' friendship pairing performed at the lowest levels. Both boy and girl acquaintance pairings performed at mid-SRT levels. These findings were consistent across Year (in school) levels and ability levels. Interviews revealed that male and female friendship pairs were likely to participate in different types of activity, with girls being school-inclusive and boys being school-exclusive. Conclusion. Recommendations to use friendship as a basis for classroom grouping for cognitive tasks may facilitate performance of some pairings, but may also inhibit the performance of others. This is shown very clearly with regard to gender. Some of the difference in cognitive task performance may be explained by distinct, cultural (and social capital) orientations to friendship activities, with girls integrating school and educational considerations into friendship, and boys excluding school and educational considerations.

O ensino das ciências e a promoção da literacia científica na educação básica : representações e conhecimento profissional dos professores de ciências

Tese de doutoramento, Educação (Didática das Ciências), Universidade de Lisboa, Instituto de Educação, 2015