Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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Article Toward Reliable Annotation in Low-Resource NLP: A Mixture of Agents Framework and Multi-LLM Benchmarking(IEEE-Inst Electrical Electronics Engineers Inc, 2025) Onan, Aytug; Nasution, Arbi Haza; Celikten, TugbaThis paper introduces the Mixture-of-Agents (MoA) framework, a structured approach for improving the reliability of large language model (LLM)-based text annotation in low-resource NLP contexts. MoA employs coordinated agent interactions to enhance agreement, interpretability, and robustness without manual supervision. Evaluations on Turkish classification benchmarks demonstrate that MoA achieves up to 10-point improvements in macro-F1 over single-model baselines and significantly increases inter-agent consistency. Additionally, three novel reliability metrics-Conflict Rate (CR), Ambiguity Resolution Success Rate (ARSR), and Refinement Correction Rate (RCR)-are proposed to quantify annotation stability and correction dynamics. The results indicate that multi-agent coordination can substantially improve label quality, offering a scalable pathway toward trustworthy annotation in low-resource and cross-domain applications. The framework is language-agnostic and adaptable to other low-resource contexts beyond Turkish, including morphologically rich or typologically diverse languages such as Indonesian, Urdu, and Swahili. These findings highlight the scalability of MoA as a generalizable solution for multilingual and cross-domain annotation.Article Novel Methods for Depth-Based Calibration of Multiple RGBD Cameras Using Four Mutually Equidistant Spheres(IEEE-Inst Electrical Electronics Engineers Inc, 2025) CalI, Esra Tuncer; Gumustekin, SevketThis article presents novel calibration methods specifically tailored for multiple depth cameras, utilizing solely depth images. Traditional approaches often rely on infrared (IR) images of checkerboards, which, while feasible, fail to exploit the measured depth values, leading to calibration inaccuracies and 3-D misregistration errors. To overcome this limitation, we designed a 3-D tetrahedron object comprising four spheres placed at each corner. By employing an ellipse-fitting technique, we accurately identified the sphere centers in the depth images. Using these centers, we utilized 3-D reprojection errors and measured depths within a bundle adjustment framework to jointly determine the calibration parameters for four depth cameras. Our proposed methods significantly reduce error values compared with those obtained using IR images of checkerboards. The versatility of our techniques ensures their applicability to various types of depth cameras, independent of their underlying technologies. Here, we demonstrate that by integrating depth information directly into the calibration process, we achieve remarkable improvements. Our first method reduces the average system reconstruction error by 78.98%, while our second method, which introduces a novel cost function tailored to the tetrahedron object, achieves an even more substantial reduction of 82.32%. These results underscore the superiority of our depth-integrated calibration approach, particularly in the context of 3-D reconstruction involving multiple depth cameras.Article A Hybrid Actuation System for Enhancing the Performance Metrics Related to Kinesthetic-Type Haptic Devices(IEEE-Inst Electrical Electronics Engineers Inc, 2025) Kucukoglu, Sefa Furkan; Can Dede, Mehmet ismetHigh torque to volume ratio, fast response, and high dynamic range are some of the desired performance metrics for kinesthetic-type haptic device actuation systems. In this article, we present a hybrid actuation system consisting of an active actuator and a magnetorheological fluid-based brake (MRF brake). MRF brake's tradeoffs, namely, off-state torque and slow response (compared to an electric motor), are investigated and resolved by this hybrid actuation system. First, the transient behavior of the MRF brake is investigated and an mathematical model is proposed to mimic its transient response behavior. It is found that the performance of the proposed model performs better than the conventionally used first-order transfer function. Second, hybrid actuation system is constructed. The active actuator is used for compensating for the speed of the response and the off-state torque based on the proposed mathematical model of the MRF brake. It is measured that the off-state torque is largely eliminated from 0.178 to 0.008 N center dot m, the dynamic range is enlarged from 15 to 42.4 dB, and its time constant is improved from 69.6 to 4.4 ms when the hybrid actuation system is used instead of just an MRF brake.Article Citation - WoS: 2Semantic Communications in 6G: Coexistence, Multiple Access, and Satellite Networks(IEEE-Inst Electrical Electronics Engineers Inc, 2025) Ahmed, Ishtiaque; Sun, Yingzhuo; Fu, Jingwen; Kose, Alper; Musavian, Leila; Xiao, Ming; Ozbek, BernaThe exponential growth of wireless users and bandwidth constraints necessitates innovative communication paradigms for next-generation networks. Semantic Communication (SemCom) emerges as a promising solution by transmitting extracted meaning rather than raw bits, enhancing spectral efficiency and enabling intelligent resource allocation. This paper explores the integration of SemCom with conventional Bit-based Communication (BitCom) in heterogeneous networks, highlighting key challenges and opportunities. We analyze multiple access techniques, including Non-Orthogonal Multiple Access (NOMA), to support coexisting SemCom and BitCom users. Furthermore, we examine multi-modal SemCom frameworks for handling diverse data types and discuss their applications in satellite networks, where semantic techniques mitigate bandwidth limitations and harsh channel conditions. Finally, we identify future directions for deploying semantic-aware systems in 6G and beyond.Article Citation - WoS: 4Citation - Scopus: 3Design of Energy Efficient Multi-Haps Assisted Hybrid Rf/Fso Satellite Communication Systems With Optimal Placement(IEEE-Inst Electrical Electronics Engineers Inc, 2025) Ece Turk, Sare; Safahan Ahrazoglu, Evla; Erdogan, Eylem; Altunbas, IbrahimSatellites and high altitude platform station (HAPS) systems are expected to become the key elements of non-terrestrial networks with the recent advances on sixth-generation (6G) wireless networks. In this article, motivated by the mounting interest in HAPS systems both from academia and industry, we propose a multi-HAPS aided optical satellite communication architecture using hybrid radio frequency (RF)/free space optical (FSO) communication to provide enhanced throughput, and reliability. The proposed architecture can be used in railways, transcontinental highways or maritime communications to provide enhanced coverage, throughput and reliability. To quantify the overall performance of the proposed scenario, outage probability, ergodic capacity, throughput, energy efficiency are obtained and validated. Additionally, the impact of outdated channel state information and channel estimation errors are considered, severely affecting the system performance by causing signal-to-noise ratio loss and outage floors. Furthermore, we find optimum HAPS distance and obtain the number of HAPS systems that is required for reliable communications. The results show that serial placement of HAPS systems at optimum distances can enhance the system performance and energy efficiency.Article Citation - WoS: 1Citation - Scopus: 2New Security Proofs and Complexity Records for Advanced Encryption Standard(IEEE-Inst Electrical Electronics Engineers Inc, 2023) Kara, OrhunCommon block ciphers like AES specified by the NIST or KASUMI (A5/3) of GSM are extensively utilized by billions of individuals globally to protect their privacy and maintain confidentiality in daily communications. However, these ciphers lack comprehensive security proofs against the vast majority of known attacks. Currently, security proofs are limited to differential and linear attacks for both AES and KASUMI. For instance, the consensus on the security of AES is not based on formal mathematical proofs but on intensive cryptanalysis over its reduced rounds spanning several decades. In this work, we introduce new security proofs for AES against another attack method: impossible differential (ID) attacks. We classify ID attacks as reciprocal and nonreciprocal ID attacks. We show that sharp and generic lower bounds can be imposed on the data complexities of reciprocal ID attacks on substitution permutation networks. We prove that the minimum data required for a reciprocal ID attack on AES using a conventional ID characteristic is 2(66) chosen plaintexts whereas a nonreciprocal ID attack involves at least 2(88) computational steps. We mount a nonreciprocal ID attack on 6-round AES for 192-bit and 2(56)-bit keys, which requires only 2(18) chosen plaintexts and outperforms the data complexity of any attack. Given its marginal time complexity, this attack does not pose a substantial threat to the security of AES. However, we have made enhancements to the integral attack on 6-round AES, thereby surpassing the longstanding record for the most efficient attack after a period of 23 years.