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Permanent URI for this collectionhttps://ada.atilim.edu.tr/handle/123456789/19

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Afthd: Bayesian Accelerated Failure Time Model for High-Dimensional Time-To Data
(Springernature, 2025) Kumari, Pragya; Bhattacharjee, Atanu; Vishwakarma, Gajendra K.; Tank, Fatih
Analyzing high-dimensional (HD) data with time-to-event outcomes poses a formidable challenge. The accelerated failure time (AFT) model, an alternative to the Cox proportional hazard model in survival analysis, lacks sufficient R packages for HD time-to-event data under the Bayesian paradigm. To address this gap, we develop the R package afthd. This tool facilitates advanced AFT modeling, offering Bayesian analysis for univariate and multivariable scenarios. This work includes diagnostic plots and an open-source R code for working with HD data, extending the conventional AFT model to the Bayesian framework of log-normal, Weibull, and log-logistic AFT models. The methodology is rigorously validated through simulation techniques, yielding consistent results across parametric AFT models. The application part is also performed on two different real HD liver cancer datasets, which reveals the proposed method's significance by obtaining inferences for survival estimates for the disease. Our developed package afthd is competent in working with HD time-to-event data using the conventional AFT model along with the Bayesian paradigm. Other aspects, like missing values in covariates within HD data and competing risk analysis, are also covered in this article.
Citation - Scopus: 5
Challenges of using software size in agile software development: A systematic literature review
(CEUR-WS, 2018) Hacaloglu,T.; Demirors,O.; Information Systems Engineering
Software size is a fundamental measure for software management. Size is used for a variety of purposes, such as benchmarking, normalization, and portfolio measurement, and it is frequently considered as the sole input of estimation. Estimations can be produced for various reasons; e.g., to predict effort, cost and duration of software development projects. There are different types of software size measures. Particularly in projects where agile methodologies are adopted, measurement becomes a significant challenge as it is perceived as a non-value-added task and records of tasks such as requirements identification are not always consistent. The difficulties of applying traditional size measurement techniques in agile contexts, however, do not diminish the need, and new methods and techniques are introduced to improve the manageability of the agile projects. In this paper, we discuss estimation and measurement approaches in relation with ―software size in agile contexts. Based on this review, we present the perceptions of software size and related challenges, such as misinterpretation of size, difficulties in implementation, and acceptability of the measurement processes. We anticipate that providing a baseline for the state of software size measures in agile contexts and presenting related challenges, particularly in terms of its acceptability by practitioners can shed light on the development of new techniques. © 2018 CEUR-WS. All rights reserved.
Citation - Scopus: 0
Clinical Development of Quinone-Based Drugs
(Elsevier, 2024) Altuner, E.E.; Issa, G.; Ozalp, V.C.; Aldemir, O.; Torlak, Y.; Dar, U.A.
This chapter provides a detailed explanation of the clinical investigations, pharmacological effects, and characteristics of quinone and quinone derivatives, along with references to pertinent sources. Although quinones have an oxygen group in their structure, they are quickly oxidized and interact with reactive oxygen species. This demonstrates how quinones work as drugs. Quinones and their derivatives are used as medications to treat a wide range of diseases, including cancer, lung, kidney, brain, and tumor disorders. Each of the following has effects on a different area of health; lapochols, anthraquinones, naphthoquinone and its derivatives, and other wide range of quinone derivatives are thoroughly explored in this chapter. © 2025 Elsevier Inc. All rights reserved.
Citation - Scopus: 0
Comparative Analysis Of Patch Antennas With Rectangular Slots For Laminate And Wearable Materials At 5g Networks
(Institute of Electrical and Electronics Engineers Inc., 2024) Hakanoglu, B.G.; Agaya, E.; Gulmez, G.; Yalinsu, S.
In this study, new multi-band patch antenna design models are proposed for use in 5G networks. The purpose of the designs is to open rectangular slots on rectangular shaped patch antennas and bring them to the desired operating conditions with parametric analyzes. The designs were carried out by following the same procedure steps using five different dielectric laminate substrate materials, such as RO3003, RT6006, FR4, RO3203, RO6010, and one denim fabric base material. The antennas were compared in terms of return loss, gain and radiation characteristics. Except for the antenna designed with RO3203 at certain values of rectangular slots, radiation at multiple frequencies was obtained at 5G frequencies. With the proposed method, improvement was observed for return loss and bandwidth characteristics in the RO3203 based antenna. This study will be a resource for antenna researchers by revealing the responses of different substrate materials to the same design method for 5G bands in patch antennas. © 2024 IEEE.
A Comparison of Stream Processing Frameworks
(Institute of Electrical and Electronics Engineers Inc., 2017) Karakaya,Z.; Yazici,A.; Alayyoub,M.; Software Engineering; Computer Engineering
This study compares the performance of Big Data Stream Processing frameworks including Apache Spark, Flink, and Storm. Also, it measures the resource usage and performance scalability of the frameworks against a varying number of cluster sizes. It has been observed that, Flink outperforms both Spark and Storm under equal constraints. However, Spark can be optimized to provide the higher throughput than Flink with the cost of higher latency. © 2017 IEEE.
Complex Partial Differential Equations
(Springer, 2025) Aksoy, Ü.; Begehr, H.; Çelebi, A.; Shupeyeva, B.
The Schwarz and iterated Dirichlet boundary-value problems are reported on for the polyanalytic operator in certain plane domains having a harmonic Green function. Hybrid polyharmonic Green functions are reviewed upon which open a variety of boundary-value problems for the polyharmonic operator. This topic is far from being complete. The higher the order of the polyharmonic operator the richer is the theory of related hybrid Green functions: they are constructed by continued convoluting harmonic Green, Neumann, Robin functions also incorporating polyharmonic Green–Almansi functions. © The Author(s), under exclusive licence to Springer Nature Switzerland AG 2025.
Citation - Scopus: 1
A computer-controlled triaxial swelling test apparatus
(2004) Bilir,M.E.; Müftüoǧlu,Y.V.; Sari,D.
To avoid the problems encountered during and after the construction of engineering structures built within swelling rocks or soils, data related to swelling stresses and strains should be used in the design stage. For an effective design, it is important that the data used for this purpose should be derived from triaxial swelling tests. In this article, a re-designed and computer-controlled triaxial swelling test apparatus is introduced. Due to the limited amount of test equipment, the work associated with triaxial swelling tests has been rather limited and consequently a test standard has not been developed yet. The computer-controlled triaxial swelling test apparatus has made tedious swelling tests easier and thus it has provided better possibilities for the investigation of the triaxial swelling behavior of soils and rocks.
Citation - Scopus: 0
Deep Learning Based Covid-19 Detection Using Computed Tomography Images
(Prof.Dr. İskender AKKURT, 2024) Yılmaz, A.A.; Sevinç, Ö.
The infectious coronavirus disease (COVID-19), seen in Wuhan city of China in December 2019, led to a global pandemic, resulting in countless deaths. The healthcare sector has become extensively use of deep learning (DL), a method that is currently quite popular. The aim of this study is to identify the best and most successful deep learning model and optimizer approach combination for COVID-19 diagnosis. For this reason, several DL methods and optimizer techniques are tested on two comprehensive public data set to select the best DL model with optimizer technique. A variety of performance evaluation metrics, including f-score, precision, specificity, and accuracy, were used to assess the models' effectiveness. The experimental results show that the most suitable and effective architecture is DenseNet-201 in the network comparison, which achieved a 98% accuracy rate using the AdaGrad optimizer and 200 iterations. © IJCESEN.
Determination of Metabolic Rate From Physical Measurements of Heart Rate, Mean Skin Temperature and Carbon Dioxide Variation
(Sakarya University, 2022) Özbey, M.F.; Çeter, A.E.; Turhan, C.; Energy Systems Engineering; Mechanical Engineering
Thermal comfort depends on four environmental parameters such as air temperature, mean radiant temperature, air velocity and relative humidity and two personal parameters, including clothing insulation and metabolic rate. Environmental parameters can be measured via objective sensors. However, personal parameters can be merely estimated in most of the studies. Metabolic rate is one of the problematic personal parameters that affect the accuracy of thermal comfort models. International thermal comfort standards still use a conventional metabolic rate table which is tabulated according to different activity tasks. On the other hand, ISO 8996 underestimates metabolic rates, especially when the time of activity level is short and rest time is long. To this aim, this paper aims to determine metabolic rates from physical measurements of heart rate, mean skin temperature and carbon dioxide variation by means of nineteen sample activities. 21 male and 17 female subjects with different body mass indices, sex and age are used in the study. The occupants are subjected to different activity tasks while heart rate, skin temperature and carbon dioxide variation are measured via objective sensors. The results show that the metabolic rate can be estimated with a multivariable non-linear regression equation with high accuracy of 0.97. © 2022, Sakarya University. All rights reserved.
Citation - Scopus: 1
Development of a low cost radio controller for Tele operation systems: Crane controller design as an industry sponsored undergraduate research
(2013) Kaynaköz,G.; Daǧdeviren,B.; Kapusuz,K.Y.; Kara,A.; Department of Electrical & Electronics Engineering
This study presents some of the design and development stages of a radio control system for dense interference environments. All design and development stages were conducted by undergraduate students, with an undergraduate research project sponsored by a local company. The study starts with an overview of the system including choice of main components and modules. Then, it discusses the design stages of the system from analog to digital conversion to driving circuit of the targeted mechanical system (crane), and provides some preliminary results and conclusions. One of the design criteria in the project was minimization of the cost and size, and the preliminary results have shown that the prototype could compete with many commercial equivalents.
Citation - Scopus: 0
Development of a single degree of freedom inertial measurement system
(2013) Kara,S.E.; Golmohammedzadeh,H.; Arikan,K.B.; Department of Mechatronics Engineering
A test bench is designed to develop an inertial measurement unit. Micro electromechanical system (MEMS) type gyro and accelerometer sensors are placed on a rotating platform. Actual angular position is measured by an encoder. This paper presents design of various estimators to estimate the orientation of the test platform. Basically complementary and Kalman filter based estimators are designed and implemented on the test bench. Parameters of the estimators are optimized by using experimental data. Satisfactory results are achieved.
Citation - Scopus: 1
The Effect of a 6-Week Balance Exercise Program on Balance Parameters in Frailty Syndrome: a Randomized Controlled, Double-Blind, Prospective Study
(Georgian Association of Business Press, 2023) Karagül, S.; Kibar, S.; Ay, S.; Evcik, D.; Ergin, S.
Objective: This study assessed the effectiveness of a six-week balance exercise program on balance parameters and fall frequency in geriatric patients with frailty syndrome. Methodology: This randomized prospective study evaluated a total of 216 patients after referral to a physical medicine and rehabilitation outpatient clinic. Participants were divided into group 1 (flexibility exercises) and group 2 (balance exercises, including kinesthetic ability trainer [KAT] balance exercises, and flexibility exercises). Both groups performed exercises five days per week for six weeks. Balance assessments included the Berg Balance Scale and time-up-and-go test to evaluate dynamic and functional balance, while the one-leg stand test and KAT 4000 static balance test were done to evaluate static balance. Results: Frailty was observed in 37 patients (17.12%). Patients without frailty syndrome initially performed significantly better (p <0.001). Group 2 demonstrated statistically significant improvements after six weeks (p <0.05). Conclusion: Long-term exercise programs improve balance parameters and exercise performance in older adults with frailty. © 2023 Georgian Association of Business Press. All rights reserved.
Citation - Scopus: 0
The Effect of Gamification on Brand Awareness: a Study of Retail Industry and Healthy-Living Applications
(Henry Stewart Publications, 2024) Alsan, H.; Tengilimoğlu, D.
Rapid developments in digitisation have resulted in gamification (ie, the use of game elements and game mechanics in non-game areas) becoming more common and easy to apply in digital environments. This study examines the use of gamification in the field of marketing, specifically its effects on brand awareness. As the paper shows, gamification helps to establish important bonds between the brand, the company and the customer. In this context, the paper analyses brand awareness by means of the survey method. Due to the size of the study population, the scope of the study was narrowed to apps promoting healthy living and apps produced by the retail sector. Convenience sampling was used to recruit 400 respondents. The survey found that gamification has a positive effect on brand awareness (r = 0.55) and that attitude to gamified apps has a positive effect on brand awareness (r = 0.58). Certain demographic factors were also found to influence the use of gamified apps. © HENRY STEWART PUBLICATIONS 2050-0076 (2024).
Effect of Tool Cavity Conditions on Damping, Chatter Mitigation, and Surface Quality in Internally Cooled Milling Tools
(Elsevier B.V., 2025) Namlu, R.H.; Dogan, H.; Ozsoy, M.
Chatter is a critical factor limiting productivity and efficiency in machining processes. Cutting tools significantly impact chatter stability, as they often serve as the most flexible component. The influence of cutting tools on chatter varies depending on their design and cooling mechanisms. Internally cooled cutting tools, commonly used in industrial applications, have the potential to exhibit distinct damping characteristics due to the presence of internal cavities, differentiating them from conventional solid tools. This study explores the effects of internally cooled milling cutting comparing an empty cavity cutting tool with a tool filled with viscous fluid. The primary objective is to evaluate how these conditions influence the damping of the machining system and their subsequent impact on surface quality, a key outcome sensitive to chatter. Surface topography and roughness measurements were taken after the experiments to assess changes in surface quality. The findings offer valuable insights into the role of internal cooling and fluid properties in not only chatter but also vibration suppressions in milling operations, highlighting their potential to enhance machining performance. © 2025 The Author(s).
Citation - Scopus: 0
ELECTROCHEMICAL HYDROGEN SEPARATION FROM REFORMATE USING POLYBENZIMIDAZOLE/MOF COMPOSITE MEMBRANES
(International Association for Hydrogen Energy, IAHE, 2022) Durmuş,G.N.B.; Eren,E.O.; Devrim,Y.; Ozgur Colpan,C.; Özkan,N.; Mechanical Engineering; Energy Systems Engineering
This study introduces the experimental results of a high-temperature electrochemical hydrogen purification (ECHP) cell through poly 2.2-m-phenylene-5.5-bibenzimidazole/metal organic framework (PBI/MOF) composite membranes in the temperature range of 140°C-180°C. Synthesis of ZIF-8 and UiO-66 MOFs was conducted through a typical solvothermal method, and composite membranes containing 2.5 wt. %. MOF was fabricated. Experiments were conducted with pure hydrogen (H2) and reformate gas mixtures containing H2, carbon monoxide (CO), and carbon dioxide (CO2). A gas chromatography device (GC) was used to analyze the gas composition at the exit of the ECHP cell. The final output H2 purity was found to be >99.9 % for the H2/CO2/CO mixed-phase and >99.7% for the H2/CO mixed phase. © 2022 Proceedings of WHEC 2022 - 23rd World Hydrogen Energy Conference: Bridging Continents by H2. All rights reserved.
Citation - WoS: 0
Citation - Scopus: 0
Estimation of the Mean Radiant Temperature in Office Buildings Using an Artificial Neural Network Developed in a Phyton Environment
(Taylor & Francis Ltd, 2025) Ozbey, Mehmet Furkan; Lotfi, Bahram; Turhan, Cihan
Thermal comfort describes an occupant's state of mind in a thermal environment, influenced by six parameters: air velocity, relative humidity, air temperature, mean radiant temperature (MRT), clothing value, and metabolic rate. MRT is the most problematic parameter since the obtaining process is difficult and time-consuming. MRT can be acquired by several methods such as calculations, measurements, assumptions, and software programmes. However, the methods have complexities and uncertainties. Comprehensive models are needed to obtain MRT. To this aim, this study presents an alternative method using one of the artificial intelligence methods, Artificial Neural Network (ANN), to predict MRT for indoor environments to abstain from the difficulties and complexities. A case building is selected in a university office building in Ankara, T & uuml;rkiye. The proposed model is developed and coded in a Python programming environment to predict the MRT using ANN. The results indicate that the ANN model, using only four inputs, predicts MRT with an R-2 value of 0.94 compared to the globe thermometer measurement method. The model's advantages over methods include simplicity, time efficiency and learning from the limited datasets such as difficulty in calculating terms like MRT.
Citation - Scopus: 0
Examination of the Relationship Between Money Laundering and Tax Crimes Based on Financial Action Task Force (FATF) Standards: a Stocktaking for Turkiye
(Sosyoekonomi Soc, 2025) Bulbul, Duran; Guler, Kadir
Money laundering and tax crimes are financial crimes that have considerable costs to society, and there are notable interconnections between them. This study aims to examine the contribution of the measures introduced against money laundering by the Financial Action Task Force (FATF) to tax compliance and combating tax crimes and to evaluate the situation in T & uuml;rkiye. The conceptual framework regarding these crimes and the connections between them are established in this context. The effects of the measures introduced against money laundering on tax compliance and crimes based on FATF standards are investigated. Finally, the situation in T & uuml;rkiye is examined and analysed. The study shows that customer identification and reporting of suspicious transactions can contribute significantly to identifying taxpayers, transactions, and income that should be taxed and detecting tax evasion. Still, this potential is not sufficiently utilised in our country.
Experiences of Parents Who Have Children With Disabilities: A Qualitative Study From Türkiye During Covid-19
(Lippincott Williams and Wilkins, 2025) Acar, S.; Er, D.M.; Volk, K.T.; Spence, C.M.
This study aimed to understand the experiences of parents who have young children with disabilities in Türkiye during COVID-19. We conducted a qualitative analysis of semistructured virtual interviews with eight parents. We used a collective within-case and across-case approach to analyze and interpret the interviews. Parents noted difficulties with the EI/ECSE programs and the need for individualized and functional services for their children. Furthermore, parents reported the need for high-quality, inclusive early childhood programs and the importance of well-trained educators. Parents also expressed interest in learning more about how to support their child's development and learning. Results may inform research, policy, and practice initiatives for children with disabilities and their families. The findings highlight the importance of including parent voices in the continued capacity-building efforts of EI/ECSE systems. Copyright © 2025 Wolters Kluwer Health, Inc. All rights reserved.
Citation - Scopus: 0
Exploratory Review of Quantum Computing Software Requirements Specification and Their Measurement
(CEUR-WS, 2024) Hacaloglu, T.; Soubra, H.; Bourque, P.
Quantum software sets itself apart from classical software owing to its powerful computational abilities rooted in entanglement and superposition. Unlike classical software, quantum software diverges notably across various dimensions, including computational models, hardware architectures, algorithms, deployment platforms, and problem domains. Quantum software is also often not standalone and interacts heavily with classical software, stressing the importance of carefully considering hybridization. From a software engineering standpoint, researchers generally agree that a different approach is required for quantum software, and they advocate a Quantum Software Development Life Cycle (SDLC). This exploratory study briefly outlines the specifics of quantum software, overviews the proposed approaches regarding the software requirements of quantum software, and then reviews the current alternatives for measuring the functional size of quantum software. This study indicates that only a few papers in the literature discuss the requirements and functional size measurements of quantum software. Their results are also mostly conceptual and have not yet been empirically validated. Functional size measurement using quantum software remains an open area for further research. © 2024 Copyright for this paper by its authors.
Citation - Scopus: 4
Exploring the Influence of Countries Economic Conditions on Massive Open Online Course (Mooc) Participation: A Study of 3.5 Million Mitx Learners
(2023) Cagiltay, N.E.; Toker, S.; Cagiltay, K.; Information Systems Engineering
It is well known that there are disparities in access to education around the world, with developed countries generally having better educational resources and opportunities compared to developing countries. Massive open online courses (MOOCs) have been proposed as a way to bridge this gap by providing free or low-cost online education to anyone with an Internet connection. This study aimed to better understand the effects of location, both country and region, on the use of MOOCs, using data from 3.5 million learners who registered for MOOCs offered by the Massachusetts Institute of Technology (MIT). The data set provided a broad picture of how MOOCs are being used around the globe. The results of the study indicated significant differences in the use of MOOCs among students from different countries and their corresponding economic levels. In order to address these differences and improve access to education through MOOCs, the study suggested several actions that could be taken. These include providing better infrastructure and support for MOOC learners in developing countries, increasing awareness of and access to MOOCs in these regions, and working to improve the quality and relevance of MOOC offerings. Overall, the study highlighted the potential of MOOCs to bridge the educational gap between developed and developing countries, but also emphasized the need for continued efforts to remove barriers and improve access to these resources. © (2023), All Rights Reserved.

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