200 research outputs found
Dynamics of 8CB confined into porous silicon probed by incoherent neutron backscattering experiments
Confinement in the nanochannels of porous silicon strongly affects the phase
behavior of the archetype liquid-crystal 4-n-octyl-4-cyanobiphenyl (8CB). A
very striking phenom- enon is the development of a short-range smectic order,
which occurs on a very broad temperature range. It suggests in this case that
quenched disorder effects add to usual finite size and surface interaction
effects. We have monitored the temperature variation of the molecular dynamics
of the confined fluid by incoherent quasielastic neutron scat- tering. A
strongly reduced mobility is observed at the highest temperatures in the liquid
phase, which suggests that the interfacial molecular dynamics is strongly
hindered. A continuously increasing slowdown appears on cooling together with a
progressive growth of the static correlation lengt
EXPERIMENTAL AND FINITE ELEMENT ANALYSIS REGARDING THE INFLUENCE OF FRICTION CONDITIONS ON MATERIAL FLOW IN METAL FORMING PROCESSES
When friction occurs between tool and workpiece, surface expansion and high normal pressure between work piece and die, leads to adhesions(cold-weld), abrasion of die and work material. To reduce the friction, it requires a suitable lubricant. In the present work different lubricated condition were tested in the extrusion process of lead. The influence of lubricated conditions on the material flow and process parameters were determined. Experimental values were compared with simulation
FINITE ELEMENT ANALYSIS OF FRICTION PARAMETERS ON 6060 ALUMINIUM ALLOY IMPRESSION DIE COLD FORGING PROCESS
In this paper cold forging process of aluminium alloy 6060 is simulated and analyzed at different stages of forging and with different quality of lubricants. Finite element (FE) method is extensively employed in solving linear and non-linear problems and widely used particularly in analyzing a forming process. Three-dimensional modeling of initial material and die are performed by Solid Works, while simulation and analysis of forging are performed by Forge. Based on the computer simulation the required dies are designed and the workpieces are formed
Supporting systematic reviews using LDA-based document representations
BACKGROUND: Identifying relevant studies for inclusion in a systematic review (i.e. screening) is a complex, laborious and expensive task. Recently, a number of studies has shown that the use of machine learning and text mining methods to automatically identify relevant studies has the potential to drastically decrease the workload involved in the screening phase. The vast majority of these machine learning methods exploit the same underlying principle, i.e. a study is modelled as a bag-of-words (BOW). METHODS: We explore the use of topic modelling methods to derive a more informative representation of studies. We apply Latent Dirichlet allocation (LDA), an unsupervised topic modelling approach, to automatically identify topics in a collection of studies. We then represent each study as a distribution of LDA topics. Additionally, we enrich topics derived using LDA with multi-word terms identified by using an automatic term recognition (ATR) tool. For evaluation purposes, we carry out automatic identification of relevant studies using support vector machine (SVM)-based classifiers that employ both our novel topic-based representation and the BOW representation. RESULTS: Our results show that the SVM classifier is able to identify a greater number of relevant studies when using the LDA representation than the BOW representation. These observations hold for two systematic reviews of the clinical domain and three reviews of the social science domain. CONCLUSIONS: A topic-based feature representation of documents outperforms the BOW representation when applied to the task of automatic citation screening. The proposed term-enriched topics are more informative and less ambiguous to systematic reviewers. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s13643-015-0117-0) contains supplementary material, which is available to authorized users
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Diamonds, gold and crime displacement: Hatton Garden, and the evolution of organised crime in the UK
The 2015 Hatton Garden Heist was described as the ‘largest burglary in English legal history’. However, the global attention that this spectacular crime attracted to ‘The Garden’ tended to concentrate upon the value of the stolen goods and the vintage of the burglars. What has been ignored is how the burglary shone a spotlight into Hatton Garden itself, as an area with a unique ‘upperworld’ commercial profile and skills cluster that we identify as an incubator and facilitator for organised crime. The Garden is the UK’s foremost jewellery production and retail centre and this paper seeks to explore how Hatton Garden’s businesses integrated with a fluid criminal population to transition, through hosting lucrative (and bureaucratically complex) VAT gold frauds from 1980 to the early 1990s, to become a major base for sophisticated acquisitive criminal activities. Based on extensive interviews over a thirty year period, evidence from a personal research archive and public records, this paper details a cultural community with a unique criminal profile due to the particularities of its geographical location, ethnic composition, trading culture, skills base and international connections. The processes and structures that facilitate criminal markets are largely under-researched (Antonopoulos et al. 2015: 11), and this paper considers how elements of Hatton Garden’s ‘upperworld’ businesses integrated with project criminals, displaced by policing strategies, to effect this transition
Feature engineering and a proposed decision-support system for systematic reviewers of medical evidence
Objectives: Evidence-based medicine depends on the timely synthesis of research findings. An important source of synthesized evidence resides in systematic reviews. However, a bottleneck in review production involves dual screening of citations with titles and abstracts to find eligible studies. For this research, we tested the effect of various kinds of textual information (features) on performance of a machine learning classifier. Based on our findings, we propose an automated system to reduce screeing burden, as well as offer quality assurance. Methods: We built a database of citations from 5 systematic reviews that varied with respect to domain, topic, and sponsor. Consensus judgments regarding eligibility were inferred from published reports. We extracted 5 feature sets from citations: alphabetic, alphanumeric +, indexing, features mapped to concepts in systematic reviews, and topic models. To simulate a two-person team, we divided the data into random halves. We optimized the parameters of a Bayesian classifier, then trained and tested models on alternate data halves. Overall, we conducted 50 independent tests. Results: All tests of summary performance (mean F3) surpassed the corresponding baseline, P<0.0001. The ranks for mean F3, precision, and classification error were statistically different across feature sets averaged over reviews; P-values for Friedman's test were .045, .002, and .002, respectively. Differences in ranks for mean recall were not statistically significant. Alphanumeric+ features were associated with best performance; mean reduction in screening burden for this feature type ranged from 88% to 98% for the second pass through citations and from 38% to 48% overall. Conclusions: A computer-assisted, decision support system based on our methods could substantially reduce the burden of screening citations for systematic review teams and solo reviewers. Additionally, such a system could deliver quality assurance both by confirming concordant decisions and by naming studies associated with discordant decisions for further consideration. © 2014 Bekhuis et al
Căile aeriene dificile în chirurgia maxilo-facială (Caz clinic)
Catedra Anesteziologie şi Reanimatologie Nr 1 „Valeriu Ghereg”, USMF „Nicolae Testemiţanu”, Centrul Naţional Ştiinţifico-Practic de Medicină de Urgenţă, Chişinău, Moldova, Catedra Chirurgie Orală şi Maxilo-Facială, USMF „Nicolae Testemiţanu”, Congresul II Internaţional al Societăţii Anesteziologie Reanimatologie din Republica Moldova 27-30 august 2009Confruntarea cu un pacient neventilat şi neintubat reprezintă o încercare serioasă pentru anestezist. Identificarea pacienţilor
cu risc de intubare dificilă este un pas esenţial în examenul preanestezic ce poate reduce morbiditatea şi mortalitatea legată de căile
aeriene dificile. Aplicarea anesteziei generale, a sedării intravenoase induce depresie respiratorie, care necesită asistenţă respiratorie
cu protejarea căilor aeriene. Intubarea dificilă este definită ca necesitatea de a efectua mai mult de 3 încercări de intubare, sau mai
mult de 10 minute, utilizând laringoscopie clasică. Laringoscopia dificilă este atunci, când nu este posibil de a vedea nici o porţiune
a corzilor vocale prin laringoscopie clasică.
În prezicerea căilor aeriene dificile sunt importante următoarele: anamnesticul, examinarea, măsurările, sistemele de scoruri,
eşecurile
Wonder, education, and human flourishing:Theoretical, empirical, and practical perspectives
The premise that underlies this volume is that there are strong interconnections between wonder, education and human flourishing. And more specifically, that wonder can make a significant difference to how well one’s education progresses and how well one’s life goes. The contributors to this volume – both senior, well-known and beginning researchers and students of wonder – variously explore aspects of these connections from philosophical, empirical, theoretical and practical perspectives. The three chapters that comprise Part I of the book are devoted to the importance of wonder for education and for human flourishing. Part II contains four chapters offering conceptual analyses of wonder and perspectives from developmental psychology and philosophy (Spinoza, Wittgenstein, philosophy of religion). The seven chapters that form Part III contain a wealth of ideas and educational strategies to promote wonder in education and teacher education. This volume not only underlines and articulates the importance of wonder in education and in life but also offers fresh perspectives, allowing us to look with renewed wonder at wonder itself
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