177 research outputs found
The analogue of grad-div stabilization in DG methods for incompressible flows: Limiting behavior and extension to tensor-product meshes
No full textSchroeder, Philipp W./0000-0001-7644-4693WOS: 000442638700037grad-div stabilization is a classical remedy in conforming mixed finite element methods for incompressible flow problems, for mitigating velocity errors that are sometimes called poor mass conservation. Such errors arise due to the relaxation of the divergence constraint in classical mixed methods, and are excited whenever the spatial discretization has to deal with comparably large and complicated pressures. In this contribution, an analogue of grad-div stabilization for Discontinuous Galerkin methods is studied. Here, the key is the penalization of the jumps of the normal velocities over facets of the triangulation, which controls the measure-valued part of the distributional divergence of the discrete velocity solution. Our contribution is twofold: first, we characterize the limit for arbitrarily large penalization parameters, which shows that the stabilized nonconforming Discontinuous Galerkin methods remain robust and accurate in this limit; second, we extend these ideas to the case of non-simplicial meshes; here, broken grad-div stabilization must be used in addition to the normal velocity jump penalization, in order to get the desired pressure robustness effect. The analysis is performed for the Stokes equations, and more complex flows and Crouzeix-Raviart elements are considered in numerical examples that also show the relevance of the theory in practical settings. (C) 2018 Elsevier B.V. All rights reserved.German Academic Exchange Service (DAAD)Deutscher Akademischer Austausch Dienst (DAAD); program "Research Grants for Doctoral Candidates and Young Academics and Scientists", 2017/18 [57299291]; National Science FoundationNational Science Foundation (NSF) [DMS1522191]; U.S. ArmyUnited States Department of Defense [65294-MA]The authors would especially like to thank Christoph Lehrenfeld for several related fruitful discussions on stabilization and hybridization and the invaluable help he provided in using the finite element library NGSolve in the context of this work. Mine Akbas acknowledges support from the German Academic Exchange Service (DAAD) with the program "Research Grants for Doctoral Candidates and Young Academics and Scientists", 2017/18 (57299291). The third author was supported by National Science Foundation grant DMS1522191 and U.S. Army grant 65294-MA
Reliability Analysis of an Anchored Contiguous Pile Wall in Ankara Clay with the Random Set Finite Element Method
No full textA deep excavation application characterized by imprecise data and lack of adequate information is used to demonstrate the efficiency, applicability, and validity of the random set theory in combination with finite element method (RS-FEM). A case history of an anchored contiguous pile wall in overconsolidated fissured Ankara Clay constructed for supporting the 15 m deep basement excavation of a nursing house in Seyranbaglari district of Ankara is considered. Existing buildings around the excavation area necessitated a careful examination of the wall deformations and the reliability of the system as a whole. However, the geotechnical parameters of the soil had to be estimated combining the results of very limited in-situ and laboratory tests with those obtained through previous experience of finite element analyses under similar conditions, i.e., expert knowledge. Plane strain finite element analyses were then performed to predict the contiguous pile retaining wall behavior. The parameters in the random set finite element model were chosen according to sensitivity analyses. Most likely bounds of the wall horizontal deformations were compared with those obtained from inclinometer readings. As suggested by previous case histories, wall deformations were observed to fall within the lower third of the range predicted by RS-FE
A New Text Steganography Method By Using Non-Printing Unicode Characters
No full textOne of the methods used in security areas is steganography. Steganography is the artand science of hiding information by embedding messages within cover media withoutattracting attention. the cover media can be text, image, video or audio files. Textsteganography is more difficult than others due to the difficulty in finding redundantinformation in text file. This paper presents a new idea for text steganography by usingUnicode standard characters, (which have the non-printing properties) to encode theletters of English language and embedding the secret message letter by letter into thecover-text.This method has high hiding capacity, it can hide (K+1) letters in a text with Kcharacters and it does not make any apparent changes in the original text. So it satisfiesperceptual transparency
Comparison of Fitting Performance of Random Regression Models to Test Day Milk Yields in Holstein Friesians
No full textIn this study, random regression models with Ali-Schaeffer functions, Wilmink functions and orthogonal Legendre polynomials were compared for fitting performance to test day milk yields. Legendre polynomials with orders from two to six for additive genetic and permanent environmental effects were fitted under homogeneous error variance assumption throughout lactation. The analyzes were applied to 5918 first lactation test day milk yields of 612 Holstein Friesian cows calving from 1987 to 1993 in Dalaman, Tahirova, Sarimsakli and Turkgeldi State Farms. To compare the models, residual variances, -2LogL value, Akaike's information criterion, Bayesian information criterion and eigenvalues for additive genetic and permanent environmental random regression (co)variance matrix were used. Among 27 models, the L(6,2), L(6,5) and L(6,6) were chosen as better models
Probabilistic Slope Stability Analyses Using Limit Equilibrium and Finite Element Methods
No full textThis paper compares the results of different probabilistic approaches and emphasizes the necessity of probabilistic analyses in slope stability studies. To do that, Limit Equilibrium Method (LEM) and Finite Element Method (FEM) are utilized and their outputs are compared in terms of probability of failure (PF), reliability index (RI), factor of safety (FS) and the failure surface. Lastly, concept of Random Finite Element Method (RFEM) is studied and effects of spatial correlation distance are investigate
Synthesis and structural and thermal properties of cyclotriphosphazene-based ionic liquids: tribological behavior and OFET application
No full textThree new fully substituted starting materials (Pz1-3) were synthesized reacting dimethylaminoethanol, 3-dimethylamino-1-propanol, and 4-pyrridinemethanol, which were saltified using metallic sodium, with partly substituted phosphazene (Pz) compound. Phosphazene-based ionic liquids (PzILs), PzIL1-3, were obtained from the reaction of the starting materials with CH3I. New ionic liquids (PzIL1a-3a) were obtained by replacing the I- ions of these ionic liquids with the NTf2- anions. The structures of PzILs were elucidated by elemental analysis, FTIR, and H-1, C-13 {H-1}, and P-31 {H-1} NMR techniques. The thermal properties of all compounds were investigated using thermogravimetric (TG) analysis. Compared with the output materials, the thermal stability of the ionic liquids was found to be higher, 160, 199, and 228 degrees C for PzIL1-3 respectively, and 270, 204, and 287 degrees C for PzIL1a-3a respectively. At the same time, the viscosity measurements of PzIL1a-3a compounds obtained as liquids in room temperature were measured with a cone/plate viscometer. It is understood from the viscosity values that the fluidities of these compounds are as low as 864, 3801, and 423,700cP, respectively (water viscosity is 0.7977cP at 30 degrees C). In addition to these studies, sliding wear test was conducted at room temperature using AA7075 disc specimen against the stationary 100Cr6 steel ball. The wear protection of PzILs was determined considering the volume loss of AA7075
An observational study to evaluate factors responsible and actions taken for hypertensive patients who are not at blood pressure goal: i-target Goal Study
No full textWOS: 000305001900010PubMed ID: 22318207To evaluate the percentage of hypertensive patients who could achieve target blood pressure (TBP) according to the guidelines in the context of recommended measures and the factors responsible for failure. A total of 589 hypertensive patients (59.0% female; mean age: 57.7+/-10.4 years) were assessed twice for TBP achievement based on 2007 ESH/ESC guidelines and the investigators' view, in addition to the recommended measures and possible causes of failure in hypertension management in this national multi-center (n = 99), non-interventional observational study. Only 29.5% of the patients at the first visit and 46.8% at the second visit achieved the TBP levels specified by the guidelines. However, the investigators' evaluation indicated a higher achievement rate at the first (43.5%) as well as the second (69.1%) visit when compared with the guideline-based assessments (P<0.001). The primary reasons identified by the investigators for the failure to reach TBP were non-compliance with dietary recommendations (61.6%) at the first visit and non-compliance with treatment (63.92%) at the second visit. Recommendations for lifestyle were the most commonly identified treatment plan by the investigators at both visits (62.9% and 66.1%, respectively). Although more patients achieved the TBP levels specified by the guidelines for the second visit compared with the first, effective blood pressure control was achieved only in 29.5% of our patients. Interestingly, the investigators had a more optimistic view about their patients' control of hypertension, which may have contributed to a poor achievement of TBP. Hypertension Research (2012) 35, 624-632; doi:10.1038/hr.2012.12; published online 9 February 2012Sanofi-Aventis TurkeyThe study was funded by Sanofi-Aventis Turkey. We thank Cagla Isman, M. D. and Professor Sule Oktay, M. D., Ph.D. from KAPPA Consultancy Traning Research Ltd., Istanbul, who provided editorial support; and Oguz Akbas, M. D., Ph.D., Esra Koruyucu and Arzu Calisgan M. Sc. from Monitor CRO, Istanbul, for their support of the statistical analysis, funded by Sanofi-Aventis Turkey
Commitment-detachment and authorial presence in postgraduate academic writing: A comparative study of Turkish native speakers, Turkish speakers of English and English native speakers.
No full textThis thesis reports an exploratory and contrastive corpus study examining two phenomena in postgraduate academic writing: expressing commitment/detachment and signalling authorial presence in dissertations. More specifically, the overall purpose of the study is to investigate how postgraduate academic writers from particular contexts build their academic stance and voice by employing a range of linguistic items that could be identified as hedges, boosters and authorial references.
The corpus consists of a total of 90 discussions sections of master’s dissertations, 30 from Turkish L1 writers, 30 from Turkish writers of English and 30 from UK English L1 writers. A range of items, discourse functions and roles were determined during the pilot study via Nvivo 9. Then, the whole corpus was searched and analysed via WordSmith 5.0 based on the linguistic item list signalling certainty/doubt or authorial presence. In order to address two crucial phenomena in dissertation writing of postgraduates represented by three groups, both quantitative and qualitative approaches were adapted. Three key findings are as follows:
1. The postgraduates polarised: they either frequently qualified their level of commitment or else they seemingly intentionally withheld their commitment from what they asserted. The tone of writing adopted by the Turkish L1 writers differed markedly from that of the English L1 & L2 writers, as evidenced by their use of linguistic signalling expressions; the English L1 and L2 writers preferred to sound more detached from their knowledge claims, compared with the Turkish L1 writers. Therefore, the findings emphasise the importance of the language factor in expressing commitment-detachment across groups.
2. The authorial references included two broad categories: (1) Explicit authorial references (I and we-based pronouns); (2) Implicit authorial references (passive and element-prominent constructions speaking for the author). The Turkish L1 writers and the Turkish writers of English (from Turkish culture) appeared to construct less personal academic prose compared with the English L1 writers. This seems to reflect a broader cultural difference.
3. In terms of the authorial roles identified in relation to the accompanying verbs, the postgraduate writers tended to appear in their discourse most frequently as (1) Research Conductor, followed by (2) Discourse Creator & Participant; then (3) Opinion Holder. The rhetorical role indicating the membership of the postgraduates to a community (either academic or institutional), (4) Community-self, was the least frequent role adopted by the postgraduates in their discussion sections.
It is recommended that, in order to raise postgraduates’ awareness about the writing conventions and practices in their disciplines, they should be provided with the standards required with respect to style via modelling from previous successful dissertations completed in their field. This is suggested as particularly important for ‘novice’ writers
Breast cancer identification based on artificial intelligent system
No full textWorldwide, breast cancer causes a high mortality rate. Early diagnosis is important for treatment, but high-density breast tissues are difficult to analyze. Computer-assisted identification systems were introduced to classify by fine-needle aspirates FNA with features that better represent the images to be classified as a major challenge. This work is fully automated, and it does not require any manual intervention from the user. In this analysis, various texture definitions for the portrayal of breast tissue density on mammograms are examined in addition to contrasting them with other techniques. We have created an algorithm that can be divided into three classes: fatty, fatty-glandular, and dense-glandular. The suggested system works in a spatial-related domain and it results in extreme immunity to noise and background area, with a high rate of precision
Constructed model for micro-content recognition in lip reading based deep learning
No full textCommunication between human beings has several ways, one of the most known and used is speech, both visual and acoustic perceptions sensory are involved, because of that, the speech is considered as a multi-sensory process. Micro contents are a small pieces of information that can be used to boost the learning process. Deep learning is an approach that dives into deep texture layers to learn fine grained details. The convolution neural network (CNN) is a deep learning technique that can be employed as a complementary model with micro learning to hold micro contents to achieve special process. In This paper a proposed model for lip reading system is presented with proposed video dataset. The proposed model receives micro contents (the English alphabet) in video as input and recognize them, the role of CNN deep learning is clearly appeared to perform two tasks, the first one is feature extraction and the second one is the recognition process. The implementation results show an efficient accuracy recognition rate for various video dataset that contains variety lip reader for many persons with age range from 11 to 63 years old, the proposed model gives high recognition rate reach to 98%
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