594 research outputs found
A Software Package for Neural Network Applications Development
Original Backprop (Version 1.2) is an MS-DOS package of four stand-alone C-language programs that enable users to develop neural network solutions to a variety of practical problems. Original Backprop generates three-layer, feed-forward (series-coupled) networks which map fixed-length input vectors into fixed length output vectors through an intermediate (hidden) layer of binary threshold units. Version 1.2 can handle up to 200 input vectors at a time, each having up to 128 real-valued components. The first subprogram, TSET, appends a number (up to 16) of classification bits to each input, thus creating a training set of input output pairs. The second subprogram, BACKPROP, creates a trilayer network to do the prescribed mapping and modifies the weights of its connections incrementally until the training set is leaned. The learning algorithm is the 'back-propagating error correction procedures first described by F. Rosenblatt in 1961. The third subprogram, VIEWNET, lets the trained network be examined, tested, and 'pruned' (by the deletion of unnecessary hidden units). The fourth subprogram, DONET, makes a TSR routine by which the finished product of the neural net design-and-training exercise can be consulted under other MS-DOS applications
GPU accelerated Nature Inspired Methods for Modelling Large Scale Bi-Directional Pedestrian Movement
Pedestrian movement, although ubiquitous and well-studied, is still not that
well understood due to the complicating nature of the embedded social dynamics.
Interest among researchers in simulating pedestrian movement and interactions
has grown significantly in part due to increased computational and
visualization capabilities afforded by high power computing. Different
approaches have been adopted to simulate pedestrian movement under various
circumstances and interactions. In the present work, bi-directional crowd
movement is simulated where an equal numbers of individuals try to reach the
opposite sides of an environment. Two movement methods are considered. First a
Least Effort Model (LEM) is investigated where agents try to take an optimal
path with as minimal changes from their intended path as possible. Following
this, a modified form of Ant Colony Optimization (ACO) is proposed, where
individuals are guided by a goal of reaching the other side in a least effort
mode as well as a pheromone trail left by predecessors. The basic idea is to
increase agent interaction, thereby more closely reflecting a real world
scenario. The methodology utilizes Graphics Processing Units (GPUs) for general
purpose computing using the CUDA platform. Because of the inherent parallel
properties associated with pedestrian movement such as proximate interactions
of individuals on a 2D grid, GPUs are well suited. The main feature of the
implementation undertaken here is that the parallelism is data driven. The data
driven implementation leads to a speedup up to 18x compared to its sequential
counterpart running on a single threaded CPU. The numbers of pedestrians
considered in the model ranged from 2K to 100K representing numbers typical of
mass gathering events. A detailed discussion addresses implementation
challenges faced and averted
A NEW METHOD FOR GENERATING VIRTUAL MODELS OF NONLINEAR HELICAL SPRINGS BASED ON A RIGOROUS MATHEMATICAL MODEL
This paper presents a new method for generating nonlinear helical spring geometries based on a rigorous mathematical formulation. The model was developed for two scenarios for modifying a spring with a stepped helix angle: for a fixed helix angle of the active coils and for a fixed overall height of the spring. It allows the development of compression spring geometries with non-linear load-deflection curves, while maintaining predetermined values of selected geometrical parameters such as the number of passive and active coils and the total height or helix angle of the linear segment of the active coils. Based on the proposed models, Python scripts were developed that can be implemented in any CAD software offering scripting capabilities or equipped with Application Programming Interfaces. Examples of scripts that use the developed model to generate the geometry of selected springs are presented. FEM analyses of quasi-static compression tests carried out for these spring models have shown that, using the proposed tools, springs with a wide range of variation in static load-deflection curves can be obtained, including progressive springs with a high degree of nonlinearity in the characteristics. The obtained load-deflection curves can be described with a high degree of accuracy by power function. The proposed method can find applications in both machine design and spring manufacturing
Visualization of three-way comparisons of omics data
BACKGROUND: Density plot visualizations (also referred to as heat maps or color maps) are widely used in different fields including large-scale omics studies in biological sciences. However, the current color-codings limit the visualizations to single datasets or pairwise comparisons. RESULTS: We propose a color-coding approach for the representation of three-way comparisons. The approach is based on the HSB (hue, saturation, brightness) color model. The three compared values are assigned specific hue values from the circular hue range (e.g. red, green, and blue). The hue value representing the three-way comparison is calculated according to the distribution of three compared values. If two of the values are identical and one is different, the resulting hue is set to the characteristic hue of the differing value. If all three compared values are different, the resulting hue is selected from a color gradient running between the hues of the two most distant values (as measured by the absolute value of their difference) according to the relative position of the third value between the two. The saturation of the color representing the three-way comparison reflects the amplitude (or extent) of the numerical difference between the two most distant values according to a scale of interest. The brightness is set to a maximum value by default but can be used to encode additional information about the three-way comparison. CONCLUSION: We propose a novel color-coding approach for intuitive visualization of three-way comparisons of omics data
Estimated probabilities of positive, vs. negative, events show separable correlations with covid-19 preventive behaviours
Research has associated optimism with better health-protective behaviours, but few studies have measured optimism or pessimism directly, by asking participants to estimate probabilities of events. We used these probability estimates to examine how optimism and/or pessimism relate to protecting oneself from COVID-19. When COVID-19 first reached Turkey, we asked a snowball sample of 494 Istanbul adults how much they engaged in various COVID-protective behaviours. They also estimated the probabilities of their catching COVID-19, and of other positive and negative events happening to them. Estimated probability of general positive events (optimism) correlated positively with officially-recommended helpful behaviours (e.g. wearing masks), but not with less-helpful behaviours (e.g. sharing ‘alternative’ COVID-related information online). Estimated probabilities of general negative events (pessimism), or of catching COVID, did not correlate significantly with helpful COVID-related behaviours; but they did correlate with psychopathological symptoms, as did less-helpful COVID-related behaviours. This shows important nuances can be revealed by measuring optimism and pessimism, as separate variables, using probability estimates.WOS:000766608100006Scopus - Affiliation ID: 60105072PMID: 35228768Social Sciences Citation IndexQ2ArticleUluslararası işbirliği ile yapılan - EVETMarch2022YÖK - 2021-22Hazira
Granular circulation in a cylindrical pan: simulations of reversing radial and tangential flows
Granular flows due to simultaneous vertical and horizontal excitations of a
flat-bottomed cylindrical pan are investigated using event-driven molecular
dynamics simulations. In agreement with recent experimental results, we observe
a transition from a solid-like state, to a fluidized state in which circulatory
flow occurs simultaneously in the radial and tangential directions. By going
beyond the range of conditions explored experimentally, we find that each of
these circulations reverse their direction as a function of the control
parameters of the motion. We numerically evaluate the dynamical phase diagram
for this system and show, using a simple model, that the solid-fluid transition
can be understood in terms of a critical value of the radial acceleration of
the pan bottom; and that the circulation reversals are controlled by the phase
shift relating the horizontal and vertical components of the vibrations. We
also discuss the crucial role played by the geometry of the boundary
conditions, and point out a relationship of the circulation observed here and
the flows generated in vibratory conveyors.Comment: 10 pages, 8 figure
Insomnia medication use and the probability of an accidental event in an older adult population
ObjectiveThis study examined the risk of accidental events in older adults prescribed a sedating antidepressant, long-acting benzodiazepine, short-acting benzodiazepine, and nonbenzodiazepine, relative to a reference group (selective melatonin receptor agonist).MethodsThis was a retrospective cohort analysis of older adults (≥65 years) with newly initiated pharmacological treatment of insomnia. Data were collected from the Thomson MarketScan(®) Medicare Supplemental and Coordination of Benefits databases (January 1, 2000, through June 30, 2006). Probit models were used to evaluate the probability of an accidental event.ResultsData were analyzed for 445,329 patients. Patients taking a long-acting benzodiazepine (1.21 odds ratio [OR]), short-acting benzodiazepine (1.16 OR), or nonbenzodiazepine (1.12 OR) had a significantly higher probability of experiencing an accidental event during the first month following treatment initiation compared with patients taking the reference medication (P < 0.05 for all). A significantly higher probability of experiencing an accidental event was also observed during the 3-month period following the initiation of treatment (1.62 long-acting benzodiazepine, 1.60 short-acting benzodiazepine, 1.48 nonbenzodiazepine, and 1.56 sedating antidepressant; P < 0.05).ConclusionsOlder adults taking an SAD or any of the benzodiazepine receptor agonists appear to have a greater risk of an accidental event compared with a reference group taking an MR
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''Endonyx'' Onychomycosis: A New Modality of Nail Invasion by Dermatophytes
Three patients with onychomycosis due toTrichophyton soudanense with an ''endonyx'' type of nail invasion are presented. Endonyx onychomycosis is clinically characterized by a diffuse milky-white discolouration of the aiected nail, in the absence of nail bed hyperkeratosis or onycholysis. Nail plate surface and nail thickness are normal. The pathology shows a contrast between the great number of fungal hyphae visible in the nail plate and the absence of fungal elements in the nail bed. The nail bed does not show in£ammatory changes or hyperkeratosis and adheres strictly to the lowermost layers of the nail plate. The hyponychium is normal and does not contain hyphae. The endonyx pattern of nail infection appears to be speci¢c to T. soudanense nail invasion and may possibly re£ect the high a⁄nity of T. soudanense to hard keratins. Key words: dermatophytes; endonyx; onychomycosis; Trichophyton soudanense
Osteopontin as a marker of endometriosis — the current state of knowledge
Endometriosis is a disease affecting mainly women of childbearing age, where ectopic endometrial lesions occur outside the uterine cavity. Its main symptoms are chronic pain, infertility and dysmenorrhea. These symptoms significantly reduce the quality of life of patients suffering from this disease. Despite advanced research, the exact etiopathogenesis of endometriosis is still unknown and various theories explaining its origin are postulated in the course of research.
Osteopontin is a protein originally discovered in the bone matrix and then in various tissues and organs of the body such as the kidneys, lungs, reproductive organs, vascular epithelial cells or some cancer cells. It is involved in processes such as cell adhesion and migration, angiogenesis and the promotion of tumor cell metastasis.
These processes play a role in the pathogenesis of endometriosis, hence intensive research on the role of osteopontin in the development of this disease is an interesting research direction
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Periungual keratoacanthoma preceded by a wart and followed by a verrucous carcinoma at the same site.
Sir, Periungual keratoacanthoma can be difficult to diagnose clinically. Its presentation may differ markedly from that of keratoacanthoma found elsewhere on the skin. The same observation concerning presentation is made for squamous cell carcinoma (SCC) of the perionychium and skin. A further distinction from SCC at these sites is the presence of human papilloma virus (HPV) in periungual squamous cell carcinoma and its routine absence at most other sites. We report the presence of oncogenic HPV 31 and 35 in a periungual keratoacanthoma, marked by the manifestation of a wart prior to and a verrucous carcinoma after the presentation of the keratoacanthoma at the same site
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