WoS İndeksli Yayınlar Koleksiyonu / WoS Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7150
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Article Citation - WoS: 4Citation - Scopus: 3Papercraft Doppler Radar Measurements Based on Covariance Eigenvalue Spectrum-Assisted Empirical Mode Decomposition(Institute of Electrical and Electronics Engineers Inc., 2025) Atac, Enes; Onay, Fatih; Karatay, AnilDoppler radar systems encounter challenges due to their high costs, cumbersome designs, and heavy weights, especially in resource-limited environments. As a promising alternative, papercraft Doppler radar has emerged, offering a lightweight, easily deployable and cost-effective solution. However, despite many advantages, papercraft-based radar faces inherent challenges due to the material used, which leads to vulnerability to external stimuli. In this article, a novel method is proposed demonstrating that papercraft Doppler radar can achieve high performance comparable to its aluminum counterparts and perform multitarget detection even in noisy environment with multiple stimuli. For the first time, we integrate a papercraft Doppler radar with the proposed covariance eigenvalue spectrum (CES)-assisted empirical mode decomposition (EMD) method, significantly improving the performance of the papercraft radar system. Single and multitarget detection, exploiting proper intrinsic mode function (IMF) selection, is achieved through the CES algorithm, which distinguishes between the target and unwanted components via proper windowing and weighting of the decomposed radar signal. According to the results, the proposed method significantly enhances multitarget movement detection and outperforms existing methods.Article Citation - WoS: 1Citation - Scopus: 1Practical and Cost-Effective Approach for Thermal Light Characterization Based on Confined Area Measurements(Institute of Electrical and Electronics Engineers Inc., 2025) Atac, Enes; Dinleyici, Mehmet SalihPhoton statistics and optical coherence measurements are essential in understanding light sources' properties and behaviors. However, the measurement setups require sophisticated detectors with short integration times. Otherwise, the results are indeed time average, which poses a significant challenge, particularly for thermal light sources due to their very short coherence times. In this article, we present a novel, practical, and low-cost measurement procedure for characterizing photon statistics and the second-order coherence function of thermal light using an ordinary charge-coupled device (CCD) camera. We focus on single-pixel analysis through the experiments since measurements of randomly distributed light in a confined region follow Bose-Einstein statistics. This way, the likelihood of averaging during detection is reduced, allowing us to extract statistical information from the spatially distributed intensity values. The outcomes prove the effectiveness of confined area measurements method by overcoming the detector's long exposure time issue.Conference Object Community Detection for Large Graphs on GPUs With Unified Memory(Institute of Electrical and Electronics Engineers Inc., 2024) Dincer, Emre; Öz, Işıl; Oz, IsilWhile GPUs accelerate applications from different domains with different characteristics, processing large datasets gets infeasible on target systems with limited device memory. Unified memory support makes it possible to work with data larger than available GPU memory. However, page migration overhead for executions with irregular memory access patterns, like graph processing workloads, induces severe performance degradation. While memory hints help to deal with page movements by keeping data in suitable memory spaces, coarse-grain configurations can still not avoid migrations for executions having diverse data structures. In this work, we target the state-of-the-art CUDA implementation of the Louvain community detection algorithm and evaluate the impacts of the fine-grained unified memory hints on the performance. Our experimental evaluation shows that memory hints configured for specific data structures reveal significant performance improvements and enable us to work efficiently with large graphs.Article Citation - WoS: 1Citation - Scopus: 2Localization of a Passive Source With a Sensor Network-Based Experimental Molecular Communication Platform(Institute of Electrical and Electronics Engineers Inc., 2024) Gulec,F.; Koda,D.Y.; Atakan,B.; Eckford,A.W.In a practical molecular communication scenario such as monitoring air pollutants released from an unknown source, it is essential to estimate the location of the molecular transmitter (TX). This paper presents a novel Sensor Network-based Localization Algorithm (SNCLA) for passive transmission by using a novel experimental platform which mainly comprises a clustered sensor network (SN) with 24 sensor nodes and evaporating ethanol molecules as the passive TX. In SNCLA, a Gaussian plume model is employed to derive the location estimator. The parameters such as transmitted mass, wind velocity, detection time, and actual concentration are calculated or estimated from the measured signals via the SN to be employed as the input for the location estimator. The numerical results show that the performance of SNCLA is better for stronger winds in the medium. Our findings show that evaporated molecules do not propagate homogeneously through the SN due to the presence of the wind. In addition, our statistical analysis based on the measured experimental data shows that the sensed signals by the SN have a log-normal distribution, while the additive noise follows a Student's t-distribution in contrast to the Gaussian assumption in the literature. © 2015 IEEE.Article Citation - WoS: 2Citation - Scopus: 1Toward Cost-Effective and Lightweight Doppler Radars: Papercraft-Based Components and Comparisons With Aluminum and 3-D Printed Alternatives(Institute of Electrical and Electronics Engineers Inc., 2024) Karatay,A.; Atac,E.; Yaman,F.Doppler radar systems have an essential role in various applications, including aviation, weather forecasting, and military surveillance. However, their high fabrication costs and heavy weight may limit their utilization in rapid prototyping, small-scale applications, and seamless transportation. To address these challenges, a novel papercraft-based approach for producing the entire Doppler radar system's horn antenna, hybrid tee, and short termination components in the X-band was investigated with details in this study, alongside conventional aluminum and 3-D printing methods. This article presents the first attempt to develop a Doppler radar using papercraft-based manufacturing. The papercraft-based approach is cost-effective, lightweight, flexible, and readily available, offering a promising route for improving and fabricating Doppler radar systems that are both affordable and accessible, particularly in resource-limited settings. The experimental results show that the papercraft-based components can perform comparably to conventional aluminum-based and 3-D-printed components, making it an innovative and cost-effective solution for fabricating Doppler radar systems. © 2023 IEEE.Conference Object Citation - WoS: 2Citation - Scopus: 3Adopting Heterogeneous Computing Modules: Experiences From a Touch Summer Workshop(Institute of Electrical and Electronics Engineers Inc., 2022) Bunde, D.P.; Ahmed, K.; Ayloo, S.; Brown-Gaines, T.; Fuentes, J.; Jatala, V.; Yeh, T.Y.We present efforts to encourage the adoption of modules for teaching heterogeneous parallel computing through a faculty development workshop. The workshop was held remotely using a novel format to exploit the advantages of a virtual format and mitigate its disadvantages. Adoption at a wide variety of institutions showed module effectiveness and also gathered feedback leading to several module improvements. We also report on the adoptions themselves, which show the importance of supporting adaptation of the modules for diverse settings. © 2022 IEEE.Conference Object Citation - WoS: 1Citation - Scopus: 2Predicting the Soft Error Vulnerability of Gpgpu Applications(Institute of Electrical and Electronics Engineers Inc., 2022) Topçu, Burak; Öz, IşılAs Graphics Processing Units (GPUs) have evolved to deliver performance increases for general-purpose computations as well as graphics and multimedia applications, soft error reliability becomes an important concern. The soft error vulnerability of the applications is evaluated via fault injection experiments. Since performing fault injection takes impractical times to cover the fault locations in complex GPU hardware structures, prediction-based techniques have been proposed to evaluate the soft error vulnerability of General-Purpose GPU (GPGPU) programs based on the hardware performance characteristics.In this work, we propose ML-based prediction models for the soft error vulnerability evaluation of GPGPU programs. We consider both program characteristics and hardware performance metrics collected from either the simulation or the profiling tools. While we utilize regression models for the prediction of the masked fault rates, we build classification models to specify the vulnerability level of the programs based on their silent data corruption (SDC) and crash rates. Our prediction models achieve maximum prediction accuracy rates of 96.6%, 82.6%, and 87% for masked fault rates, SDCs, and crashes, respectively.Article Citation - WoS: 3Citation - Scopus: 4A Novel Efficient Method for Tracking Evolution of Communities in Dynamic Networks(Institute of Electrical and Electronics Engineers Inc., 2022) Karataş, Arzum; Şahin, SerapTracking community evolution can provide insights into significant changes in community interaction patterns, promote the understanding of structural changes, and predict the evolutionary behavior of networks. Therefore, it is a fundamental component of decision-making mechanisms in many fields such as marketing, public health, criminology, etc. However, in this problem domain, it is an open challenge to capture all possible events with high accuracy, memory efficiency, and reasonable execution times under a single solution. To address this gap, we propose a novel method for tracking the evolution of communities (TREC). TREC efficiently detects similar communities through a combination of Locality Sensitive Hashing and Minhashing. We provide experimental evidence on four benchmark datasets and real dynamic datasets such as AS, DBLP, Yelp, and Digg and compare them with the baseline work. The results show that TREC achieves an accuracy of about 98%, has a minimal space requirement, and is very close to the best performing work in terms of time complexity. Moreover, it can track all event types in a single solution.Article Citation - WoS: 7Citation - Scopus: 6Anisotropic Etching of Cvd Grown Graphene for Ammonia Sensing(Institute of Electrical and Electronics Engineers Inc., 2022) Yağmurcukardeş, Nesli; Bayram, Abdullah; Aydın, Hasan; Yağmurcukardeş, Mehmet; Açıkbaş, Yaser; Peeters, François M.; Çelebi, CemBare chemical vapor deposition (CVD) grown graphene (GRP) was anisotropically etched with various etching parameters. The morphological and structural characterizations were carried out by optical microscopy and the vibrational properties substrates were obtained by Raman spectroscopy. The ammonia adsorption and desorption behavior of graphene-based sensors were recorded via quartz crystal microbalance (QCM) measurements at room temperature. The etched samples for ambient NH3 exhibited nearly 35% improvement and showed high resistance to humidity molecules when compared to bare graphene. Besides exhibiting promising sensitivity to NH3 molecules, the etched graphene-based sensors were less affected by humidity. The experimental results were collaborated by Density Functional Theory (DFT) calculations and it was shown that while water molecules fragmented into H and O, NH3 interacts weakly with EGPR2 sample which reveals the enhanced sensing ability of EGPR2. Apparently, it would be more suitable to use EGRP2 in sensing applications due to its sensitivity to NH3 molecules, its stability, and its resistance to H2O molecules in humid ambient.Article Citation - WoS: 7Citation - Scopus: 8Tracking Code Bug Fix Ripple Effects Based on Change Patterns Using Markov Chain Models(Institute of Electrical and Electronics Engineers Inc., 2022) Ufuktepe, Ekincan; Tuğlular, Tuğkan; Palaniappan, KanappanChange impact analysis evaluates the changes that are made in the software and finds the ripple effects, in other words, finds the affected software components. Code changes and bug fixes can have a high impact on code quality by introducing new vulnerabilities or increasing their severity. A recent high-visibility example of this is the code changes in the log4j web software CVE-2021-45105 to fix known vulnerabilities by removing and adding method called change types. This bug fix process exposed further code security concerns. In this article, we analyze the most common set of bug fix change patterns to have a better understanding of the distribution of software changes and their impact on code quality. To achieve this, we implemented a tool that compares two versions of the code and extracts the changes that have been made. Then, we investigated how these changes are related to change impact analysis. In our case study, we identified the change types for bug-inducing and bug fix changes using the Quixbugs dataset. Furthermore, we used 13 of the projects and 621 bugs from Defects4J to identify the common change types in bug fixes. Then, to find the change types that cause an impact on the software, we performed an impact analysis on a subset of projects and bugs of Defects4J. The results have shown that, on average, 90% of the bug fix change types are adding a new method declaration and changing the method body. Then, we investigated if these changes cause an impact or a ripple effect in the software by performing a Markov chain-based change impact analysis. The results show that the bug fix changes had only impact rates within a range of 0.4-5%. Furthermore, we performed a statistical correlation analysis to find if any of the bug fixes have a significant correlation with the impact of change. The results have shown that there is a negative correlation between caused impact with the change types adding new method declaration and changing method body. On the other hand, we found that there is a positive correlation between caused impact and changing the field type.