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Permanent URI for this collectionhttps://ada.atilim.edu.tr/handle/123456789/18

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Citation Count: 15
An accurate optical gain model using adaptive neuro-fuzzy inference system
(Natl inst Optoelectronics, 2009) Celebi, F. V.; Altindag, T.
This paper presents a single, simple, new and an accurate optical gain model based on adaptive neuro-fuzzy inference system (ANFIS) which combines the benefits of Artificial Neural Networks (ANNs) and Fuzzy Inference Systems (FISs). The dynamic optical gain model results are in very good agreement with the previously published experimental findings.
Citation Count: 0
APPLICATIONS OF NON-UNIQUE FIXED POINT THEOREM OF CIRIC TO NONLINEAR INTEGRAL EQUATIONS
(int Center Scientific Research & Studies, 2019) Sevinik-Adiguzel, Rezan; Karapinar, Erdal; Erhan, Inci M.; Mathematics
In this paper we discuss the application of the non-unique fixed point theorem of Ciric to nonlinear Fredholm integral equations. We establish an existence theorem for the solutions of such integral equations and apply the theorem to particular examples.
Citation Count: 0
Approximation of Discontinuous Functions by q-Bernstein Polynomials
(Springer international Publishing Ag, 2016) Ostrovska, Sofia; Ozban, Ahmet Yasar; Mathematics
This chapter presents an overview of the results related to the q-Bernstein polynomials with q > 1 attached to discontinuous functions on [0, 1]. It is emphasized that the singularities of such functions located on the set Jq : = {0} boolean OR {q-l}(l=0, infinity), q > 1 are definitive for the investigation of the convergence properties of their q-Bernstein polynomials.
Citation Count: 12
ASSESSING COGNITIVE COMPLEXITY IN JAVA-BASED OBJECT-ORIENTED SYSTEMS: METRICS AND TOOL SUPPORT
(Slovak Acad Sciences inst informatics, 2016) Crasso, Marco; Mateos, Cristian; Zunino, Alejandro; Misra, Sanjay; Polvorin, Pablo; Computer Engineering
Software cognitive complexity refers to how demanding the mental process of performing tasks such as coding, testing, debugging, or modifying source code is. Achieving low levels of cognitive complexity is crucial for ensuring high levels of software maintainability, which is one of the most rewardful software quality attributes. Therefore, in order to control and ensure software maintainability, it is first necessary to accurately quantify software cognitive complexity. In this line, this paper presents a software metric to assess cognitive complexity in Object Oriented (OO) systems, and particularly those developed in the Java language, which is very popular among OO programming languages. The proposed metric is based on a characterization of basic control structures present in Java systems. Several algorithms to compute the metric and their materialization in the Eclipse IDE are also introduced. Finally, a theoretical validation of the metric against a framework specially designed to validate software complexity metrics is presented, and the applicability of the tool is shown by illustrating the metric in the context of ten real world Java projects and relevant metrics from the well-known Chidamber-Kemerer metric suite.
Citation Count: 10
AN ASSESSMENT OF THE SOFTWARE ENGINEERING CURRICULUM IN TURKISH UNIVERSITIES: IEEE/ACM GUIDELINES PERSPECTIVE
(Fac Teacher Education, 2011) Mishra, Alok; Yazici, Ali; Software Engineering
Software engineering (SE) education has been emerging as an independent and mature discipline. Accordingly, various studies are being done to provide guidelines for SE education curriculum design. This paper presents software engineering education evolvement in Turkey, present SE education scenario in different universities along with the significance of software technology parks in relevance to software engineering education. The objective of this paper is to provide an assessment of SE curriculum in Turkish Universities with respect to IEEE/ACM guidelines given in SEEK (2004). This study will provide a guideline to universities conducting an SE programme at undergraduate level to align their course curriculum with IEEE/ACM guidelines (SEEK, 2004).
Citation Count: 0
Association between Rutherford Classification and CHA₂DS₂-VASc, CHADS₂ and ASCVD Scores in Peripheral Artery Disease Patients
(Bmc, 2020) Karaduman, Bilge Duran; Ayhan, Huseyin; Keles, Telat; Bozkurt, Engin
Background and Aim: The classification system is important in assessing the severity of Peripheral Artery Disease (PAD) and making the treatment decision. However, classification systems may not be sufficient and scoring systems developed to predict cardiovascular and cerebrovascular events can also be useful to assess the severity of PAD. In this study, our aim was to investigate the association of the Rutherford classification and CHADS(2), CHA(2)DS(2)-VASc and ASCVD scores in PAD patients. Method: A total of 65 consecutive patients with PAD (males 92.3%, mean age 63.0 +/- 9.2 years), who underwent percutaneous peripheral intervention were included in our retrospective study. Results: There were 16 patients in Category 2, 31 patients in Category 3, and 10 patients in Category 4 and eight patients in Category 5. The CHADS(2), CHA(2)DS(2)-VASc and ASCVD scores were found to be significantly different among the Rutherford categories and between each other. From Category 1 to 5, CHADS(2), CHA(2)DS(2)-VASc and ASCVD scores were significantly increased. When we grouped the scores as CHADS 2 <2 and <2 and CHA(2)DS(2)-VASc<4 and >= 4, it was determined that as the category increased the score group also increased. There was significantly correlation between CHADS(2), CHA(2)DS(2)-VASc and ASCVD scores with the Rutherford categories in correlation analyses. Conclusion: As far as we know, in this study which is the first study about the association of Rutherford classification and scoring systems, the major finding of the present study is that the CHADS(2), CHA(2)DS(2)-VASc and ASCVD scores was independently correlated with the severity of Rutherford Category in patients with PAD. (C) 2020 Association for Research into Arterial Structure and Physiology. Publishing services by Atlantis Press International B.V.
Citation Count: 0
Automatic Boundedness of Adjointable Operators on Barreled VH-Spaces
(Springer Basel Ag, 2022) Ay, Serdar; Mathematics
We consider the space of adjointable operators on barreled VH (Vector Hilbert) spaces and show that such operators are automatically bounded. This generalizes the well known corresponding result for locally Hilbert C*-modules. We pick a consequence of this result in the dilation theory of VH-spaces and show that, when barreled VH-spaces are considered, a certain boundedness condition for the existence of VH-space linearisations, equivalently, of reproducing kernel VH-spaces, is automatically satisfied.
Citation Count: 2
BIOACTIVITY OF APATITE-WOLLASTONITE GLASS-CERAMICS PRODUCED BY MELTING CASTING
(World Scientific Publ Co Pte Ltd, 2013) Park, Jongee; Ozturk, Abdullah; Metallurgical and Materials Engineering
Glass-ceramics containing only apatite and wollastonite crystals were produced in the system MgO-CaO-SiO2-P2O5-F by the melt casting process. The bioactivity of the glass-ceramics was determined by immersing the glass-ceramics in a simulated body fluid (SBF) and by assessing the resulting apatite formation on the free surface after various immersion durations. A 12-mu m-thick apatite layer formed on the surface of the glass-ceramic containing only apatite crystals after 20 days immersion in SBF. However, the thickness of the apatite layer formed on the surface of the glass-ceramic containing apatite and wollastonite crystals was 1 mu m. Results have shown that the bioactivity of glass-ceramic depends strongly on the type of crystal(s) developed during the glass-ceramic process and their proportion in the glassy matrix.
Citation Count: 1
Boundary Element Method for Optical Force Calibration in Microfluidic Dual-Beam Optical Trap
(Spie-int Soc Optical Engineering, 2015) Solmaz, Mehmet E.; Cetin, Barbaros; Baranoglu, Besim; Serhathoglu, Murat; Biyikh, Neemi; Manufacturing Engineering
The potential use of optical forces in microfluidic environment enables highly selective bio-particle manipulation. Manipulation could be accomplished via trapping or pushing a particle due to optical field. Empirical determination of optical force is often needed to ensure efficient operation of manipulation. The external force applied to a trapped particle in a microfluidic channel is a combination of optical and drag forces. The optical force can be found by measuring the particle velocity for a certain laser power level and a multiplicative correction factor is applied for the proximity of the particle to the channel surface. This method is not accurate especially for small microfluidic geometries where the particle size is in Mie regime and is comparable to channel cross section. In this work, we propose to use Boundary Element Method (BEM) to simulate fluid flow within the micro-channel with the presence of the particle to predict drag force. Pushing experiments were performed in a dual-beam optical trap and particle's position information was extracted. The drag force acting on the particle was then obtained using BEM and other analytical expressions, and was compared to the calculated optical force. BEM was able to predict the behavior of the optical force due to the inclusion of all the channel walls.
Citation Count: 0
Can Computers Read a Text with Stress?
(Ahmet Yesevi Univ, 2013) Uslu, I. Baran; Demir, Nurettin; Ilk, H. Gokhan; Yilmaz, A. Egemen
Today prosodic elements such as stress, intonation and melody can be examined through computer-assisted techniques. The identification and analysis of acoustic qualities provide significant clues as to the suprasegmental aspects of speech. In this study a system was designed to enable speech synthesis using a Turkish text. This synthesizer was used to analyze the melodic sructures of selected sentences. Any speech synthesized by a computer needs to be equipped with a melodic model so that it will sound natural to the ear. Within the context of this study a melodic model was also suggested, and the elements of this model were analyzed and discussed in terms of the rules of linguistics.
Citation Count: 3
CANDU reactors with reactor grade plutonium/thorium carbide fuel
(Carl Hanser verlag, 2011) Sahin, S.; Khan, M. J.; Ahmed, R.
Reactor grade (RG) plutonium, accumulated as nuclear waste of commercial reactors can be re-utilized in CANDU reactors. TRISO type fuel can withstand very high fuel burn ups. On the other hand, carbide fuel would have higher neutronic and thermal performance than oxide fuel. In the present work, RG-PuC/ThC TRISO fuels particles are imbedded body-centered cubic (BCC) in a graphite matrix with a volume fraction of 60%. The fuel compacts conform to the dimensions of sintered CANDU fuel compacts are inserted in 37 zircolay rods to build the fuel zone of a bundle. Investigations have been conducted on a conventional CANDU reactor based on GENTILLYII design with 380 fuel bundles in the core. Three mixed fuel composition have been selected for numerical calculation; (1) 10% RG-PuC + 90% ThC; (2) 30% RG-PuC + 70% ThC; (3) 50% RG-PuC + 50% ThC. Initial reactor criticality values for the modes (I), (2) and (3) are calculated as k(infinity,0) = 1.4848, 1.5756 and 1.627, respectively. Corresponding operation lifetimes are similar to 2.7, 8.4, and 15 years and with burn ups of similar to 72000, 222 000 and 366 000 MW.d/tonne, respectively Higher initial plutonium charge leads to higher burn ups and longer operation periods. In the course of reactor operation, most of the plutonium will be incinerated. At the end of life, remnants of plutonium isotopes would survive; and few amounts of uranium, americium and curium isotopes would be produced.
Citation Count: 3
Clinical outcomes after transcatheter aortic valve implantation in active cancer patients and cancer survivors
(Baycinar Medical Publ-baycinar Tibbi Yayincilik, 2021) Karaduman, Bilge Duran; Ayhan, Huseyin; Keles, Telat; Bozkurt, Engin
Background: In this study, we aimed to evaluate the clinical characteristics, perioperative, and mid-term outcomes of patients with severe symptomatic aortic stenosis and active cancer disease and cancer survivors undergoing transcatheter aortic valve implantation. Methods: Between December 2011 and March 2019, a total of 550 patients (248 males, 302 females; mean age: 77.6 +/- 7.9 years; range, 46 to 103 years) who underwent transcatheter aortic valve implantation for severe symptomatic aortic stenosis in our center were retrospectively analyzed. Baseline demographic characteristics, cancer type, laboratory data, procedural data, and outcome data of the patients were collected. The primary outcome measure was all-cause mortality at 30 days and every six months up to maximally available follow-up. Follow-up was performed at 30 days, six months, and 12 months after the procedure and annually thereafter. Results: Of the patients, 36 had a cancer diagnosis-active (n=10) or cured (n=26). The most common types of cancer were colorectal (16.6%), prostate (13.8%), leukemia (11.1%), and bladder (11.1%) cancers. Post-procedural complication rates were similar between the two groups. No mortality was observed in the cancer group at one month of follow-up. During follow-up, seven patients died within one year due to non-cardiac reasons. Although mortality at one year was higher in cancer patients, it did not reach statistical significance (23.3% vs. 11.6%, respectively; p=0.061). The estimated cumulative survival rate was 71.0% in the non-cancer group and 58.3% in the cancer group. The multivariate Cox regression analysis revealed that cancer was independently associated with cumulative mortality after adjusting for age, sex, body mass index, and atrial fibrillation (p=0.008). Conclusion: Our study results show that transcatheter aortic valve implantation is safe and feasible in active cancer patients and cancer survivors with similar short-term and mid-term mortality and procedure-related complication rates, compared to non-cancer patients.
Citation Count: 15
Common Fixed Point of Generalized Rational Type Contraction Mappings in Partially Ordered Metric Spaces
(Chiang Mai Univ, Fac Science, 2013) Chandok, Sumit; Karapinar, Erdal; Mathematics
Some common fixed point results for generalized weak contractive condition satisfying rational type expressions in the frame work of partially ordered metric spaces are obtained. The proved results generalize and extend some known results in the literature.
Citation Count: 0
A Comparison of Neural Network Approaches for Network Intrusion Detection
(Springer international Publishing Ag, 2020) Oney, Mehmet Ugur; Peker, Serhat; Software Engineering
Nowadays, network intrusion detection is an important area of research in computer network security, and the use of artificial neural networks (ANNs) have become increasingly popular in this field. Despite this, the research concerning comparison of artificial neural network architectures in the network intrusion detection is a relatively insufficient. To make up for this lack, this study aims to examine the neural network architectures in network intrusion detection to determine which architecture performs best, and to examine the effects of the architectural components, such as optimization functions, activation functions, learning momentum on the performance. For this purpose, 6480 neural networks were generated, their performances were evaluated by conducting a series of experiments on KDD99 dataset, and the results were reported. This study will be a useful reference to researchers and practitioners hoping to use ANNs in network intrusion detection.
Citation Count: 2
Constructing Stieltjes classes for M-indeterminate absolutely continuous probability distributions
(Impa, 2014) Ostrovska, Sofiya; Mathematics
If P is a moment-indeterminate probability distribution, then it is desirable to present explicitly other distributions possessing the same moments as P. In this paper, a method to construct an infinite family of probability densities - called the Stieltjes class - all with the same moments is presented. The method is applicable for densities with support (0, infinity) which satisfy the lower bound: f(x) >= A exp{-ax(alpha)} for some A > 0, a > 0 and some alpha is an element of(0, 1/2):
Citation Count: 19
Coupled coincidence point results on generalized distance in ordered cone metric spaces
(Springer, 2013) Aydi, Hassen; Karapinar, Erdal; Mustafa, Zead; Mathematics
In this paper, we establish some coupled coincidence point results in the setting of partially ordered cone metric spaces via -distance. We also proved some related coupled common fixed point theorems for such mappings. Our results generalize, extend, and unify several well-known comparable results in the literature regarding this topic. We present some examples to illustrate the concepts and results.
Citation Count: 0
COVID-19 Infection in Peritoneal Dialysis Patients: \rA Comparative Outcome Study with Patients on \rHemodialysis and Patients without Kidney Disease
(Aves, 2022) Kazancıoğlu, Rümeyza; Ozturk, Savas; Turgutalp, Kenan; Gürsu, Meltem; Arıcı, Mustafa; Oruç, Ayşegül; Ateş, Kenan
Objectives: There is limited data about coronavirus disease-19 (COVID-19) characteristics and results in peritoneal dialysis \r(PD) patients. This study aimed to investigate the characteristics and outcomes among PD patients and compare them with \rmatched hemodialysis (HD) patients and a control group without kidney disease.\rMethods: We included 18 PD patients and consecutive age- and gender-matched 18 HD and 18 patients without kidney \rdisease (control group) registered into the Turkish Society of Nephrology database including 1301 COVID-19 patients. We \rcompared demographic, clinical, radiological, laboratory data, and outcomes namely intensive care unit (ICU) admission, \rmechanical ventilation, mortality, and composite outcome (death and/or ICU admission).\rResults: ICU admission, mechanical ventilation, and mortality rates in PD patients (27.8%, 22.2%, and 22.2%, respectively) \rand the HD group (16.7%, 11.1%, and 16.7%, respectively) were higher than the control group (11.1%, 11.1%, and 5.6%, \rrespectively), but intergroup comparison did not reveal difference. A total of 11 (20.3%) patients had composite outcome \r(6 PD patients, 3 HD patients, and 2 patients in the control group). In Cox regression analysis, higher age and higher CRP level were related to increased risk of composite outcome. Adjusted rate of composite outcome in PD group was significantly higher than \rthe control group (P = .050). This rate was similar in HD and control groups (P = .30).\rConclusions: Combined in-hospital mortality and/or ICU admission of PD patients with COVID-19 was significantly higher than the control \rpatients. There is a need for careful surveillance of PD patients for infection signs and prompt treatment of COVID-19.
Citation Count: 2
Current transport mechanism in Au-p-MgO-Ni Schottky device designed for microwave sensing
(Natl inst Optoelectronics, 2016) Qasrawi, A. F.; Khanfar, H. K.; Department of Electrical & Electronics Engineering
Au/MgO/Ni back to back Schottky tunnelling barriers are designed on the surface of an MgO thin layer and are electrically characterized. The current voltage curve analysis has shown that thermionic emission, field effect thermionic (FET) emission and space charge limited current are dominant transport mechanism in distinct biasing regions. It was shown that, while the device is reverse biased with voltages less than 0.31 V, it conducts by tunnelling (FED though an energy barrier of 0.88 eV with a depletion region width of 15.7 nm. As the voltage exceeds 0.46 V, the tunnelling energy barrier is lowered to 0.76 eV and the depletion region widens and arrives at the reach-through running mode. The device was tested in the microwave electromagnetic power range that extends from Bluetooth to WLAN radiation levels at oscillating frequencies of 0.5 and 2.9 GHz. In addition, a low power resonating signal that suits mobile data is superimposed in the device. It was observed that the Au/MgO/Au sensors exhibit a wide tunability range via voltage biasing or via frequency control. The signal quality factor is 3.53 x 10(3) at 2.9 GHz. These properties reflect applicability in microwave technology as wireless and connectorized microwave amplifiers, microwave resonators and mixers.
Citation Count: 1
Deep Learning-Based COVID-19 Detection Using Lung Parenchyma CT Scans
(Springer international Publishing Ag, 2022) Kaya, Zeynep; Kurt, Zuhal; Koca, Nizameddin; Cicek, Sumeyye; Isik, Sahin; Computer Engineering
During the outbreak of the COVID-19 pandemic, it is important to improve early diagnosis using effective ways in order to lower the risks and further spread of the viruses as early as possible. This is also important when it comes to appropriate treatments and the reduction of mortality rates. In this respect, computer tomography (CT) scanning is a useful technique in detecting COVID-19. The present paper, as such, is an attempt to contribute to this process by generating an open-source, CT-based image dataset. This dataset contains the CT scans of lung parenchyma regions of 180 COVID-19 positives and 86 COVID-19 negative patients, all from Bursa Yuksek Ihtisas Training and Research Hospital. The experimental studies demonstrate that this dataset is effectively utilized deep learning-based models for diagnostic purposes. Firstly, a smart segmentation mechanism based on the k-means algorithm is applied to this dataset as a pre-processing stage. Then, the performance of the proposed method is evaluated using InceptionV3 and Xception convolutional neural networks, yielding a 96.20% and 96.55% accuracy rate and 95.00% and 95.50% F1-score, respectively. These state-of-the-art models are observed to detect COVID-19 cases faster and more accurately. In addition, the fine-tuning stage of the convolutional neural network (CNN) features sufficiently improves this accuracy rate. For these features, the support vector machine (SVM) classifier is used, resulting in remarkable 96.76% accuracy rate and 95.81% F1-score. The implications of the proposed method are immense both for present-day applications as well as future developments.
Citation Count: 0
Design Optimization of Cassegrain Telescope for Remote Explosive Trace Detection
(Spie-int Soc Optical Engineering, 2017) Bhavsar, Kaushalkumar; Eseller, K. E.; Prabhu, Radhakrishna; Department of Electrical & Electronics Engineering
The past three years have seen a global increase in explosive-based terror attacks. The widespread use of improvised explosives and anti-personnel landmines have caused thousands of civilian casualties across the world. Current scenario of globalized civilization threat from terror drives the need to improve the performance and capabilities of standoff explosive trace detection devices to be able to anticipate the threat from a safe distance to prevent explosions and save human lives. In recent years, laser-induced breakdown spectroscopy (LIBS) is an emerging approach for material or elemental investigations. All the principle elements on the surface are detectable in a single measurement using LIBS and hence, a standoff LIBS based method has been used to remotely detect explosive traces from several to tens of metres distance. The most important component of LIBS based standoff explosive trace detection system is the telescope which enables remote identification of chemical constituents of the explosives. However, in a compact LIBS system where Cassegrain telescope serves the purpose of laser beam delivery and light collection, need a design optimization of the telescope system. This paper reports design optimization of a Cassegrain telescope to detect explosives remotely for LIBS system. A design optimization of Schmidt corrector plate was carried out for Nd:YAG laser. Effect of different design parameters was investigated to eliminate spherical aberration in the system. Effect of different laser wavelengths on the Schmidt corrector design was also investigated for the standoff LIBS system.

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