137 research outputs found
The Diophantine equation revisited
No full textLet k,l >= 2 be fixed integers, and C be an effectively computable constant depending only on k and l. In this paper, we prove that all solutions of the equation (x + 1)(k) + (x + 2)(k) + ... + (lx)(k) = y(n) in integers x, y,n with x, y >= 1, n >= 2, k not equal 3 and l 1 (mod 2) satisfy max{x, y, n} < C. The case when is even has already been completed by the second author (see [24])
The Caliph Umar's Methods of Understanding and Interpreting the Qur'an
No full textThe content of this study includes Umar's methods of learning and understanding of the Qur'an and the effects of these methods in sharpening Umar's understanding of the Qur'an. Living in a sacred geography with the prophet and a community such as his distinguished companions, this experience has added greater importance to his perception and knowledge of the Qur'an. There are some methods which Umar followed to learn and understand the Qur'an. Accordingly, it has been seen that Omar had read the Qur'an many times, repeatedly, placing great importance on memorizing it and understanding it. Whenever there was a verse Umar did not completely understand, he asked people who knew, of which the prophet was his priority. He considered spreading the learning of the Qur'an, over time appropriate. It has also been seen that he has given special importance to Arabic poems to better understand verses
The validity and reliability of the Turkish version of the 6-item female sexual function index (FSFI-6) and the relationship between climacturia and female sexual dysfunction
No full text© 2021, The Author(s), under exclusive licence to Springer Nature Limited.This study aims to assess the validity and reliability of the Turkish version of the FSFI-6 questionnaire,an abbreviated version of FSFI-19,a common tool for evaluating female sexual function. The study included 120 female patients aged between 18–65 years who presented to the urology clinic between December 2019 and March 2020. The Turkish version of FSFI-6 was translated from the English version for validation. The abridged FSFI-6 questionnaire consists of questions 2, 4, 7, 11, 16, and 17 of the FSFI-19 form. We recorded the demographic data of the patients. All subjects filled out the FSFI-19 and FSFI-6 questionnaires. The patients were asked to fill out the questionnaires again after two weeks. The mean age of the subjects was 46.58 ± 9.89 years (28–63). The results of the reliability analysis indicated that the intraclass correlation coefficient of the total FSFI-6 score was 0.92 (weighted kappa coefficients of individual items, 0.868–0.975) and the Cronbach’s alpha was 0.862. The validity analysis indicated that the mean total FSFI-6 score was strongly correlated with the mean FSFI-19 score (p < 0.001, r = 0.997). In the test-retest analysis,the kappa coefficient was calculated as 0.891. The FSFI-19 and FSFI-6 scores of the patients with (n = 52) and without climacturia (n = 68) were compared, and it was observed that the scores of the patients with climacturia were significantly lower than those without climacturia (p < 0.001). The abbreviated FSFI-6 questionnaire is a valuable tool for screening women with FSD. It can be used more extensively due to being short and easy to apply. Our results approve the Turkish version of the questionnaire as a valid and reliable tool for evaluating FSD
Negative differential resistance observation and a new fitting model for electron drift velocity in GaN-based heterostructures
No full textThe aim of this paper is an investigation of electric field-dependent drift velocity characteristics for Al0.3Ga0.7N/AlN/GaN heterostructures without and with in situ Si3N4 passivation. The nanosecond-pulsed current-voltage ( {I}-{V} ) measurements were performed using a 20-ns applied pulse. Electron drift velocity depending on the electric field was obtained from the {I}-{V} measurements. These measurements show that a reduction in peak electron velocity from \text {2.01} \times \text {10}^{\text {7}} to \text {1.39} \times \text {10}^{\text {7}} cm/s after in situ Si3N4 passivation. Also, negative differential resistance regime was observed which begins at lower fields with the implementation of in situ Si3N4 passivation. In our samples, the electric field dependence of drift velocity was measured over 400 kV/cm due to smaller sample lengths. Then, a well-known fitting model was fitted to our experimental results. This fitting model was improved in order to provide an adequate description of the field dependence of drift velocity. It gives reasonable agreement with the experimental drift velocity data up to 475 kV/cm of the electric field and could be used in the device simulators.Manuscript received September 3, 2017; revised November 24, 2017 and December 26, 2017; accepted January 15, 2018. Date of publication February 8, 2018; date of current version February 22, 2018. This work was supported in part by the International Bilateral Research Project between RFBR and TUBITAK under Project 113F364, in part by the Projects DPT-HAMIT, DPT-FOTON, NATO-SET-193, and TUBITAK through the Nanotechnology Research Center, Bilkent University, Turkey under Project 113E331, Project 109A015, and Project 109E301, in part by the Distinguished Young Scientist Award of Turkish Academy of Sciences (TUBA-GEBIP 2016), and in part by the Ministry of Education and Science of the Russian Federation with the unique identifier of the project RFMEFI57717X0250. The work of E. Özbay was supported by the Turkish Academy of Sciences. The review of this paper was arranged by Editor K. Kalna. (Corresponding author: Gökhan Atmaca.) G. Atmaca, P. Narin, E. Kutlu, and S. B. Lis¸esivdin are with the Lisesivdin Research Group, Faculty of Science, Department of Physics, Gazi University, 06500 Ankara, Turkey (e-mail: gokhanatmaca@ kuark.org)
Laser micro-polishing of stainless steel for antibacterial surface applications
No full textIn this work laser micro polishing (LMP) of cold rolled 0.3 mm thick 304 stainless steel with a pulsed fibre laser is studied, for applications
where antibacterial properties are required. Due to its production method, the initial surface roughness of the tested material was considerably
low (Sa=85.3±2.8 μm), rendering a demanding case for the laser polishing process. Accordingly, process feasibility under three different
atmospheric conditions, namely ambient, Ar and N2 atmosphere, was investigated. A large set of process parameter combinations was tested
and initial analysis was carried out to identify the polishing feasibility by inspection under an optical microscope. Once the feasibility window
was determined, a primary characterization was made on selected surfaces for roughness and waviness. Results show that in some process
conditions belonging to the explored feasibility range, surface roughness could be decreased by 50%
SamenMarkt®, a Proposal for Restoring Trust in the Horticultural Fresh Food Market by Using Multi-agent System Technology
No full textIn the horticultural fresh food supply chain network in the Netherlands, a crisis is emerging. The market is out of balance and many growers are facing bankruptcy, in the period of 2011–2013, 50% of the growers were not able to pay interest and redemption. Trust between participants in the supply chain network has decreased. This chapter presents the currently not established and identiies design requirements for new systems to address this challengeand provide directions for possible improvement. As a result, this chapter introduces the concept of SamenMarkt®, a participatory system in which multi-agent system technology enables distributed price negotiation, distribution and communication between producers, retailers and consumers. A SWOT analysis of the concept of SamenMarkt® is provided together with a research and development plan in which simulation and emulation create the basis for stakeholder- and participant involvement in the design process of a distributeddigital market place. Further research aims to study how SamenMarkt® can provide a solution space for the emerging global food crises. At present, we are using agent-based modelling to simulate the present market and scenarios. The next step will be to build the actual agent-based platform for real-time negotiations and business intelligence
Hand-held spectrophotometer design for textile fabrics
No full textIn this study, a hand-held spectrophotometer was designed by taking advantage of the developments in modern optoelectronic technology. Spectrophotometer devices are used to determine the color information from the optic properties of the materials. As an alternative to a desktop spectrophotometer device we have implemented, it is the first prototype, low cost and portable. The prototype model designed for the textile industry can detect the color tone of any fabric. The prototype model consists of optic sensor, processor, display floors. According to the color applied on the optic sensor, it produces special frequency information on its output at that color value. In Arduino type processor, the frequency information is evaluated by the program we have written and the color tone information between 0-255 ton is decided and displayed on the screen
Effects of ultrathin InGaN channel layer on two dimensional electron gas in hybrid GaN/InGaN/ZnO heterostructures
No full textAutomatic and interactive segmentations using deformable and graphical models
No full textImage segmentation i.e. dividing an image into regions and categories is a classic yet still challenging problem. The key to success is to use/develop the right method for the right appli- cation. In this dissertation, we aim to develop automatic and interactive segmentation methods for different types of tissues that are acquired at different scales and resolutions from different medical imaging modalities such as Magnetic Resonance (MR), Computed Tomography (CT) and Electron Microscopy (EM) imaging. First, we developed an automated segmentation method for segmenting multiple organs simultaneously from MR and CT images. We propose a hybrid method that takes advantage of two well known energy-minimization-based approaches combined in a unified framework. We validate this proposed method on cardiac four-chamber segmentation from CT and knee joint bones segmentation from MR images. We compare our method with other existing techniques and show certain improvements and advantages. Second, we developed a graph partitioning algorithm for characterizing neuronal tissue structurally and contextually from EM images. We propose a multistage decision mechanism that utilizes differential geometric properties of objects in a cellular processing context. Our results indicate that this proposed approach can successfully partition images into structured segments with minimal expert supervision and can potentially form a basis for a larger scale volumetric data interpretation. We compare our method with other proposed methods in a workshop challenge and show promising results. Third, we developed an efficient learning-based method for segmentation of neuron struc- tures from 2D and 3D EM images. We propose a graphical-model-based framework to do inference on hierarchical merge-tree of image regions. In particular, we extract the hierarchy of regions in the low level, design 2D and 3D discriminative features to extract higher level information and utilize a Conditional Random Field based parameter learning on top of it. The effectiveness of the proposed method in 2D is demonstrated by comparing our method with other methods in a workshop challenge. Our method outperforms all participant methods ex- cept one. In 3D, we compare our method to existing methods and show that the accuracy of our results are comparable to state-of-the-art while being much more efficient. Finally, we extended our inference algorithm to a proofreading framework for manual cor- rections of automatic segmentation results. We propose a very efficient and easy-to-use inter- face for high resolution 3D EM images. In particular, we utilize the probabilistic confidence level of the graphical model to guide the user during interaction. We validate the effective- ness of this framework by robot simulations and demonstrate certain advantages compared to baseline methods.Ph.D.Includes bibliographical referencesby Mustafa Gokhan Uzunba
Learning Analytics Dashboard Widgets to Author Teaching-Learning Cases for Evidence-based Education
No full textThe 9th International Learning Analytics and Knowledge (LAK) Conference : March 4-8, 2019, Tempe, Arizona, USAIn this paper, we introduce the components of LAView, a learning dashboard that assists teachers to author criteria for different teaching-learning cases. We define indicators as the basic unit to define the status of a situation and visualise that on the dashboard. This paper describes the technology design and workflow of the teacher as the user of the dashboard from setting indicator criteria to recording reflection of their results. We conclude with the utility of such a technology support in the context of evidence-based education
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