246 research outputs found
Recommender System for the Efficient Treatment of COVID-19 Using a Convolutional Neural Network Model and Image Similarity
Get PDFBackground: Hospitals face a significant problem meeting patients’ medical needs during epidemics, especially when the number of patients increases rapidly, as seen during the recent COVID-19 pandemic. This study designs a treatment recommender system (RS) for the efficient management of human capital and resources such as doctors, medicines, and resources in hospitals. We hypothesize that a deep learning framework, when combined with search paradigms in an image framework, can make the RS very efficient. Methodology: This study uses a Convolutional neural network (CNN) model for the feature extraction of the images and discovers the most similar patients. The input queries patients from the hospital database with similar chest X-ray images. It uses a similarity metric for the similarity computation of the images. Results: This methodology recommends the doctors, medicines, and resources associated with similar patients to a COVID-19 patients being admitted to the hospital. The performance of the proposed RS is verified with five different feature extraction CNN models and four similarity measures. The proposed RS with a ResNet-50 CNN feature extraction model and Maxwell–Boltzmann similarity is found to be a proper framework for treatment recommendation with a mean average precision of more than 0.90 for threshold similarities in the range of 0.7 to 0.9 and an average highest cosine similarity of more than 0.95. Conclusions: Overall, an RS with a CNN model and image similarity is proven as an efficient tool for the proper management of resources during the peak period of pandemics and can be adopted in clinical settings
Cataglyphis laylae Cedric A. Collingwood & Donat Agosti & Mostafa R. Sharaf & Antonius van Harten 2011, nov. spec.
No full textCataglyphis laylae Collingwood nov. spec. Plates 96–103 Cataglyphis desertorum Forel, 1894, teste Collingwood, 1985; unavailable name according to Agosti (1990). Specimens examined: Holotype: 1 ☿, United Arab Emirates, al-Ain [24°13'N 55°46'E], iii.1995, leg. C.A. Collingwood (MHNG). Paratypes: 3 ☿, al-Ain zoo, 13.iii.2005, CAC. 1 ☿, Remah, 9.iii.1995, CCA. 3 ☿, Remah, resthouse, 250 m, irrigated sand dune [24°10'37"N 55°18'6"E], 18.iii.1995, leg. D. Agosti. 6 ☿, Remah, resthouse, 250 m, irrigated sand dune, nest with one entrance, [24°10'37"N, 55°18'6"E], 18.iii.1995, leg. D. Agosti. 1 ☿, Sharjah Desert Park, 5–6.x.2004, AvH; 1 ☿, 3.iii.2005, CAC. 1 ☿, al- Za'aba, 100 m, sandy soil with Rhaisa stricta [23°43'20"N, 55°33'49"E], 22.iii.1995, leg. D. Agosti. Description: A large worker from al-Ain was selected as holotype. The measurements are as follows: total length 8.40; head width 3.60; head length 4.20; scape length 3.84; funicular segment I 0.40; funicular segment II 0.23; petiole length 1.10; petiole width 0.72. Colour dark reddish brown. There are no exterior hairs on the scapes or hind tibia. The gaster, petiole and propodeum have dorsal hairs. Remarks: This species thought to correspond with C. desertorum has to be described as a new species. In fact it is one of the commonest Cataglyphis in southern Arabia. The main distinguishing feature compared with other dark Cataglyphis is the slender petiole, which has the anterior face more sloped than in other similar species such as C. niger (André, 1882) and C. savignyi (Dufour, 1862). Biology: Cataglyphus laylae nov. spec. does not appear to occur in open sandy desert and is most abundant in disturbed habitats such as man-developed plantations and open cultivated fields. Distribution: This species was recorded by Collingwood (1985) as C. desertorum from Saudi Arabia and Oman and as Cataglyphis spec. by Collingwood & Agosti (1996). Etymology: The new species is named after a village settlement called “Layla”, just north of Riyadh (Saudi Arabia) in the area where the author (CAC) first encountered it in numbers in an Acacia plantation.Published as part of Cedric A. Collingwood, Donat Agosti, Mostafa R. Sharaf & Antonius van Harten, 2011, Order Hymenoptera, family Formicidae, pp. 1-70 in Arthropod fauna of the UAE 4 on page 54, DOI: 10.5281/zenodo.116858
Correction: Surgical specialists face higher a risk for malpractice compared to their non-surgical colleagues
No full textCorrection to: Scientific Reportshttps://doi.org/10.1038/s41598-024-81058-x, published online 05 December 2024 The original version of this Article contained an error in the spelling of the author M. M. Mokhles which was incorrectly given as Mostafa Mokhles. The original Article has been corrected
A new refined approach to the formulation of the earthquake-resistant design regulations for torsionally coupled multistorey buildings
No full textAppendix A: Journal article has been removed due to copyright. Rady, M. A. & Hutchinson, G. L. (1988). Evaluation of dynamic eccentricities obtained using a probabilistic approach, response spectrum methods and modern building codes. Earthquake Engineering and Structural Dynamics, 16(2),275-291. DOI: 10.1002/eqe.4290160209Deposited with permission of the author. © 1989 Dr. Mostafa Aly RadyThis thesis presents a detailed parametric study of the elastic earthquake response of torsionally coupled single and multi storey buildings using a probabilistic approach. The aim is to validate the findings of previous deterministic studies, to assess the empirical design procedures stipulated by the current provisions of building codes, and to critically appraise the alternative design recommendations made by the earlier deterministic studies.
The structural models are idealised by a discrete parameter prismatic shear beam model which is representative of low to moderately high rise frame-type buildings. The earthquake horizontal ground motion is modeled as a Gaussian, zero mean, stationary random process that is fully characterised by a probabilistic ground acceleration power spectrum. The first and second order statistical parameters defining such a spectrum are derived from an ensemble of 68 actual earthquake motions recorded in the west coast of the U.S.A. A new procedure called the Intensity Correlated Probabilistic Power Spectrum Method (ICPPSM) is developed. This procedure uses the standard random vibration and extreme value theories, and the new concept of the intensity correlated probabilistic power spectrum to compute the mean peak structural responses.
Based on the numerical results obtained from the probabilistic approach, a more rational three-step formulation to the codified seismic torsional provisions is proposed to allow for the coupling effects in the design of multi storey buildings
User Scheduling in Massive MIMO: A Joint Deep Learning and Genetic Algorithm Approach
No full textDue to the limited number of radio frequency (RF) chains in millimeter wave (mmWave) massive multiple-input multiple-output (MIMO) receivers using analog beamforming/hybrid beamforming, there is a restriction in scheduling the number of users in each transmission time interval. Therefore, fast and low-complexity user scheduling methods based on the instantaneous channel state information (CSI) are needed. In this paper, we propose novel user scheduling methods based on deep learning (DL) to reduce the size of the search space by using the learning capability of a deep neural network (DNN). We formulate the user scheduling combinatorial optimization problem as a regression problem followed by a user separation procedure through decision boundaries that are learned by a trained DNN. The decision boundaries are used to separate the users into two subsets. Then, one of the subsets is selected to be searched to find the users that maximize the sum-rate capacity. The proposed method can achieve a very low outage probability with a few number of searches. In order to achieve ergodic capacity with lower computation complexity, the proposed method is employed in combination with the genetic algorithm (GA) algorithm to take advantage of intelligent initial population selection. Our simulation results show that the proposed user scheduling methods can offer remarkably low complexity.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Signal Processing System
Lignoselluloosa- ja selluloosamateriaalien kehittyneet kuvantamismenetelmät
No full textAbstractLignocelluloses and their structural components are the most abundant biopolymeric materials. They are a renewable and biodegradable source for several applications (e.g., paper, packaging, and functional materials). Potential innovations related to lignocelluloses are foreseen both in the traditional product sectors such as packaging, hygiene, and tissue paper products, and multiple new areas, ranging from electronics to biomedicine. These innovations are based on novel forms of sustainable materials, such as nano- and microscale celluloses. For instance, nanocellulose films are tough, durable, and biodegradable. Their properties (e.g., mechanical strength and optical properties) can be altered when combined with functional fillers. Understanding the composition of lignocellulosic biomass and the structure of its different material designs is crucial for its efficient use. However, the material analysis of lignocelluloses is not straightforward; thus, easy-to-use analytical techniques are needed. Advanced imaging techniques offer appealing possibilities in lignocellulose analysis. This thesis aimed to investigate and understand various lignocellulose and cellulose materials, i.e., delignified wood fibers (thermomechanical pulp (TMP) fibers), tissue paper, and nanocellulose films, using advanced imaging techniques. The objective was to harness new techniques that can provide detailed information on the spatial distribution of material constituents and the structure and dynamics of physicochemical phenomena of materials derived from lignocelluloses. Fluorescence lifetime imaging tracked the delignification process based on a eutectic mixture and its effect on the TMP fiber characteristics, where it was found that cellulose poses fluorescent characteristics, and that lignin starts dissipating from the outer most layer of the fibers. The topography of tissue paper was tracked using noninvasive laser confocal microscopy, and measured the affect of the production on tissue paper’s softness. The morphology and chemical composition of hybrid nanocellulose films was measured in tandem using scanning transmission soft X-ray microscopy. The structure correlated to the mechanical properties, showing that agglomeration affects the mechanical behavior of the hybrid films at a certain point. Finally, the color change of thermochromic nanocellulose films was studied using optical microscopy and UV-vis spectroscopy, showing that the color change happens gradually in relation to temperature and humidity.Original papersOriginal papers are not included in the electronic version of the dissertation.Ismail, M. Y., Sirviö, J. A., Ronkainen, V.-P., Patanen, M., Karvonen, V., & Liimatainen, H. (2022). Wood fibers delignified with eutectic mixture of carvacrol and methanosulfonic acid – Analysis of structure and fractional distribution of lignin, cellulose, and hemicellulose. Manuscript in preparation.Ismail, M. Y., Patanen, M., Kauppinen, S., Kosonen, H., Ristolainen, M., Hall, S. A., & Liimatainen, H. (2020). Surface analysis of tissue paper using laser scanning confocal microscopy and micro-computed topography. Cellulose, 27, 8989–9003. https://doi.org/10.1007/s10570-020-03399-wSelf-archived versionIsmail, M. Y., Patanen, M., Sirviö, J. A., Visanko, M., Ohigashi, T., Kosugi, N., Huttula, M., & Liimatainen, H. (2019). Hybrid films of cellulose nanofibrils, chitosan and nanosilica—Structural, thermal, optical, and mechanical properties. Carbohydrate Polymers, 218, 87–94. https://doi.org/10.1016/j.carbpol.2019.04.065Self-archived versionKarzarjeddi, M., Ismail, M. Y., Sirviö, J. A., Wang, S., Mankinen, O., Telkki, V.-V., Patanen, M., Laitinen, O., & Liimatainen, H. (2022). Adjustable hydro-thermochromic green nanofoams and films obtained from shapable hybrids of cellulose nanofibrils and ionic liquids for smart packaging. Chemical Engineering Journal, 443, 136369. https://doi.org/10.1016/j.cej.2022.136369Self-archived versionTiivistelmäBiomassat ja niiden johdannaiset, erityisesti selluloosa, ligniini ja hemiselluloosa (lignoselluloosat) ovat luonnon yleisimpiä biopolymeerejä, joita voidaan käyttää uusiutuvina ja biohajoavina raaka-aineina useissa sovelluksissa (esim. paperi-, ja pakkausmateriaaleissa ja funktionaalisissa kemikaaleissa). Fossiilisiin raaka-aineisiin liittyvien ympäristöongelmien vuoksi on tärkeää löytää uusiutuvia materiaaleja ja lisätä biopohjaisten vaihtoehtojen käyttöä. Lignoselluloosamateriaalien tutkimus ja niihin liittyvät innovaatiot ovat olennaisessa osassa ympäristön kannalta kestävien tuotteiden kehityksessä. Erilaiset kuvantamis- ja karakterisointimenetelmät ovat keskeisiä näiden materiaalien tutkimuksessa. Tässä väitöstyössä on keskitytty erityisesti kehittyneiden kuvantamismenetelmien soveltamiseen biomassapohjaisten lignoselluloosamateriaalien ja tuotteiden analysoinnissa. Työssä tutkittiin (ligno)selluloosamateriaalien, kuten puukuitujen (ns. TMP-kuiduttujen) delignifiointia uusilla vihreillä liuottimilla sekä pehmopaperituotteiden ja nanoselluloosakalvojen hienorakennetta ja kemiallisia ja fysikaalisia ominaisuuksia. Työn tulokset luovat perustaa biomassojen tutkimukselle kehittyneitä ja uudenaikaisia kuvantamistekniikoita käyttäen.OsajulkaisutOsajulkaisut eivät sisälly väitöskirjan elektroniseen versioon.Ismail, M. Y., Sirviö, J. A., Ronkainen, V.-P., Patanen, M., Karvonen, V., & Liimatainen, H. (2022). Wood fibers delignified with eutectic mixture of carvacrol and methanosulfonic acid – Analysis of structure and fractional distribution of lignin, cellulose, and hemicellulose. Manuscript in preparation.Ismail, M. Y., Patanen, M., Kauppinen, S., Kosonen, H., Ristolainen, M., Hall, S. A., & Liimatainen, H. (2020). Surface analysis of tissue paper using laser scanning confocal microscopy and micro-computed topography. Cellulose, 27, 8989–9003. https://doi.org/10.1007/s10570-020-03399-wRinnakkaistallennettu versioIsmail, M. Y., Patanen, M., Sirviö, J. A., Visanko, M., Ohigashi, T., Kosugi, N., Huttula, M., & Liimatainen, H. (2019). Hybrid films of cellulose nanofibrils, chitosan and nanosilica—Structural, thermal, optical, and mechanical properties. Carbohydrate Polymers, 218, 87–94. https://doi.org/10.1016/j.carbpol.2019.04.065Rinnakkaistallennettu versioKarzarjeddi, M., Ismail, M. Y., Sirviö, J. A., Wang, S., Mankinen, O., Telkki, V.-V., Patanen, M., Laitinen, O., & Liimatainen, H. (2022). Adjustable hydro-thermochromic green nanofoams and films obtained from shapable hybrids of cellulose nanofibrils and ionic liquids for smart packaging. Chemical Engineering Journal, 443, 136369. https://doi.org/10.1016/j.cej.2022.136369Rinnakkaistallennettu versioAcademic dissertation to be presented with the assent of the Doctoral Programme Committee of Technology and Natural Sciences of the University of Oulu for public defence in the Arina auditorium (TA105), Linnanmaa, on 5 May 2023, at 12 noonAbstract
Lignocelluloses and their structural components are the most abundant biopolymeric materials. They are a renewable and biodegradable source for several applications (e.g., paper, packaging, and functional materials). Potential innovations related to lignocelluloses are foreseen both in the traditional product sectors such as packaging, hygiene, and tissue paper products, and multiple new areas, ranging from electronics to biomedicine. These innovations are based on novel forms of sustainable materials, such as nano- and microscale celluloses. For instance, nanocellulose films are tough, durable, and biodegradable. Their properties (e.g., mechanical strength and optical properties) can be altered when combined with functional fillers. Understanding the composition of lignocellulosic biomass and the structure of its different material designs is crucial for its efficient use. However, the material analysis of lignocelluloses is not straightforward; thus, easy-to-use analytical techniques are needed. Advanced imaging techniques offer appealing possibilities in lignocellulose analysis. This thesis aimed to investigate and understand various lignocellulose and cellulose materials, i.e., delignified wood fibers (thermomechanical pulp (TMP) fibers), tissue paper, and nanocellulose films, using advanced imaging techniques. The objective was to harness new techniques that can provide detailed information on the spatial distribution of material constituents and the structure and dynamics of physicochemical phenomena of materials derived from lignocelluloses. Fluorescence lifetime imaging tracked the delignification process based on a eutectic mixture and its effect on the TMP fiber characteristics, where it was found that cellulose poses fluorescent characteristics, and that lignin starts dissipating from the outer most layer of the fibers. The topography of tissue paper was tracked using noninvasive laser confocal microscopy, and measured the affect of the production on tissue paper’s softness. The morphology and chemical composition of hybrid nanocellulose films was measured in tandem using scanning transmission soft X-ray microscopy. The structure correlated to the mechanical properties, showing that agglomeration affects the mechanical behavior of the hybrid films at a certain point. Finally, the color change of thermochromic nanocellulose films was studied using optical microscopy and UV-vis spectroscopy, showing that the color change happens gradually in relation to temperature and humidity.Tiivistelmä
Biomassat ja niiden johdannaiset, erityisesti selluloosa, ligniini ja hemiselluloosa (lignoselluloosat) ovat luonnon yleisimpiä biopolymeerejä, joita voidaan käyttää uusiutuvina ja biohajoavina raaka-aineina useissa sovelluksissa (esim. paperi-, ja pakkausmateriaaleissa ja funktionaalisissa kemikaaleissa). Fossiilisiin raaka-aineisiin liittyvien ympäristöongelmien vuoksi on tärkeää löytää uusiutuvia materiaaleja ja lisätä biopohjaisten vaihtoehtojen käyttöä. Lignoselluloosamateriaalien tutkimus ja niihin liittyvät innovaatiot ovat olennaisessa osassa ympäristön kannalta kestävien tuotteiden kehityksessä. Erilaiset kuvantamis- ja karakterisointimenetelmät ovat keskeisiä näiden materiaalien tutkimuksessa. Tässä väitöstyössä on keskitytty erityisesti kehittyneiden kuvantamismenetelmien soveltamiseen biomassapohjaisten lignoselluloosamateriaalien ja tuotteiden analysoinnissa. Työssä tutkittiin (ligno)selluloosamateriaalien, kuten puukuitujen (ns. TMP-kuiduttujen) delignifiointia uusilla vihreillä liuottimilla sekä pehmopaperituotteiden ja nanoselluloosakalvojen hienorakennetta ja kemiallisia ja fysikaalisia ominaisuuksia. Työn tulokset luovat perustaa biomassojen tutkimukselle kehittyneitä ja uudenaikaisia kuvantamistekniikoita käyttäen
Is Free Cash Flow Helpful in Investment Decisions? The Case of the U.S. Materials Industry Sector
Get PDFThe purpose of this study is to identify the accounting definition of free cash flow (FCF) that is the most relevant to investors in the materials companies. Using correlations and multiple regression analysis on a sample of 12,121 observations covering the 30-year period from 1988 to 2021, the author concludes that the FCF that has the most significant association with stock price changes of materials companies, after controlling for many factors that may affect stock prices, is the one defined as cash flow from operations less cash flow for capital expenditures less cash outflow for preferred stock dividends. The author recommends that investors contemplating investing in materials companies choose companies with high FCF computed using this definition. The author further recommends that materials companies that wish to voluntarily disclose FCF in their annual report should use this definition of FCF
Analysis of natural convection flow characteristics in a square cavity with internal elliptic shape block
No full textNumerical generation of omnistrain failure envelopes
No full textTraditional failure criteria for composites are usually formulated in material coordinates and depend on all three inplane stresses, hence failure evaluation depends on the ply angle. The omnistrain failure envelope describes the most critical failure envelope in strain space irrespective of ply orientation. This independence of ply orientation leads to an isotropic failure criterion that depends only on the principal strains. Omnistrain envelopes greatly simplify the task of design and optimisation of composite laminates. This paper proposes a numerical technique to generate omnistrain failure envelopes for different composite failure criteria. The failure index, describing how far a point in strain space is from the failure boundary, is used to describe the failure surface. Assuming convexity of the failure surface, a set of points is generated on the surface, and the convex hull algorithm is used to generate a polygonal approximation of the failure surface. Representing strains in terms of principal strains and the angle between the principal and material coordinates, allows us to eliminate the angle analytically by considering the worst case condition. The omnistrain envelope is thus directly generated from the approximate three-dimensional failure surface. The proposed algorithm does not require analytic expressions of the failure surface. An adaptive algorithm is proposed to generate the omnistrain envelope with relatively small number of points. As demonstration of the proposed algorithm, the omnistrain envelopes for various composite materials are generated for a number of composite failure criteria. The omnistrain envelopes generated for the Tsai-Wu criteria accurately match to existing analytic expressions.Aerospace Structures & Computational Mechanic
A comparative study of different methods to calculate degrees of composite action for insulated concrete sandwich panels
No full textPrecast concrete sandwich wall panels consist of two outer wythes of precast concrete separated by a middle layer of insulation. In recent years, Fiber-Reinforced Polymer (FRP) shear connectors have been increasingly used since they have lower thermal conductivity compared to traditional steel shear connectors, which can significantly reduce thermal bridging. However, FRP shear connectors have lower stiffness, resulting in partial Degree of Composite Action (DCA), which is an important parameter to describe the structural behavior of the panels. Different methods have been proposed to calculate DCAs, including displacement method, strain method, and load method. This paper will compare and evaluate the effectiveness of these methods. A bending test was conducted on a full size of 7 m × 3 m, precast, prestressed insulated concrete sandwich panel with FRP shear connectors. A non-linear Finite Element (FE) model is created, where good correlations can be achieved between the test and FE results. The FE model is further employed to conduct a parametric study by varying the stiffness of the shear connectors. DCAs for different stiffnesses are calculated using the aforementioned three methods and the applicability and limitation of each method are investigated.Peer reviewe
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