İstanbul Gelişim Üniversitesi Kurumsal Açık Erişim Arşivi
DSpace@Gelişim, İstanbul Gelişim Üniversitesi tarafından doğrudan ve dolaylı olarak yayınlanan; kitap, makale, tez, bildiri, rapor, araştırma verisi gibi tüm akademik kaynakları uluslararası standartlarda dijital ortamda depolar, Üniversitenin akademik performansını izlemeye aracılık eder, kaynakları uzun süreli saklar ve yayınların etkisini artırmak için telif haklarına uygun olarak Açık Erişime sunar.
Güncel Gönderiler
Öğe Türü: Öğe , Multi-Modal Foundation Models for Space-Air-Ground Integrated 6G and Beyond Networks: A Survey and Tutorial(Institute of Electrical and Electronics Engineers Inc., 2026) Khan, Wali Ullah; Adil, Muhammad; Malik, Jahanzaib; Sheemar, Chandan Kumar; Chatzinotas, Symeon; AlQahtani, Salman Ali; Yahya, KhalidSpace–air–ground integrated networks (SAGINs) are emerging as a key architectural paradigm for 6G and beyond wireless systems, enabling seamless connectivity by integrating terrestrial radio access networks with aerial platforms and non-terrestrial networks (NTNs). The operation of SAGINs, however, departs significantly from conventional terrestrial assumptions due to high mobility, Doppler dynamics, intermittent connectivity, long and variable round-trip times, gateway bottlenecks, and strong cross-layer coupling. These characteristics motivate intelligence frameworks that leverage heterogeneous contextual information beyond traditional radio frequency (RF) measurements. This paper presents a comprehensive survey and tutorial on multi-modal foundation models (FMs) for SAGINcentric 6G systems. The survey first introduces a structured taxonomy of SAGIN data modalities, including RF/channel state information (CSI), topology graphs, trajectories and ephemeris, telemetry and traffic traces, weather and atmospheric context, and sensing signals enabled by integrated sensing and communication (ISAC). It then reviews representation and tokenization strategies for heterogeneous wireless modalities and surveys emerging architecture families for multi-modal FMs, including early, late, and hybrid fusion designs, cross-attention mechanisms, mixture-of-experts models, hierarchical multi-timescale architectures, and retrieval-augmented frameworks. The paper further summarizes training paradigms such as masked modeling, cross-modal contrastive learning, and predictive pretraining, together with adaptation strategies including parameter-efficient fine-tuning, continual learning, and federated updates. In addition, the survey discusses system-level considerations for integrating multi-modal FMs into network control loops and deployment environments, covering distributed inference, model compression, intermittencyaware operation, and safety constraints. Finally, the paper outlines benchmarking principles for evaluating multi-modal intelligence in SAGINs and identifies key open research challenges and future directions for building robust, deployable AI-native 6G networks.Öğe Türü: Öğe , Deep Bernoulli Optimisation for Solving 2D/3D Ψ-Tempered Fractional Optimalcontrol Problems(Taylor and Francis Ltd., 2026) Rahimkhani, Parisa; Abdeljawad, ThabetThis study introduces two- and three-dimensional optimal control problems characterised by theψ-tempered fractional derivative and proposes a novel numerical methodology based on deepfractional-order Bernoulli optimisation to achieve their efficient solution. To this end, the problemsunder consideration are first reformulated as equivalent variational problems. Subsequently, a deepneural network employing the fractional-order Bernoulli functions and sinh as activation functions isutilised to approximate the state variable. To facilitate the effective implementation of the proposedmethod, we construct several integral operators of both integer and ψ-tempered fractional ordersbased on the basis functions derived from the deep neural network. These operators are discretisedvia the Fejér quadrature rule adapted to the ψ-tempered fractional calculus, ensuring stability andhigh-precision integration. The proposed approach converts the 2D/3D ψ-tempered fractional opti-mal control problem into an algebraic system using deep neural networks with integral operatorsand Gauss–Legendre integration, which is efficiently solved via Newton’s method. The proposedmethod combines simple implementation, low computational cost, and high accuracy. Its effective-ness and robustness are validated through several representative 2D and 3D examples, confirmingthe method’s applicability to complex fractional optimal control problems.Öğe Türü: Öğe , Bigel-Based Low-Fat Sponge Cake Production for Palm Oil Replacement(Springer, 2026) Genç Yılmaz, Ezgi; Akçiçek, Alican; Çimen, Sümeyra; Karasu, Salih; Boğa, Tuğçe; Tekin Çakmak, Zeynep Hazal; Dertli, EnesThe development of healthier and sustainable fat replacers in bakery products has become a priority due to health concerns and environmental issues associated with palm oil. To the best of our knowledge, this is the first work to demonstrate the synergistic functionality of soy wax, beeswax, and citrus fiber in a bigel system intended for fat replacement in bakery products. In this study, food-grade bigels were formulated by combining oleogels structured with soy wax and beeswax (3%, 5%, 7%, and 10%) with 5% citrus fiber hydrogels at two phase ratios (40:60 and 60:40, oleogel:hydrogel). The rheological, textural, thermal, microstructural, and centrifugal stability properties of these bigels were systematically characterized and compared with palm oil. Rheological analyses revealed that all bigels exhibited solid-like behavior (G'>G''), with (10BW OG)60-HG40 showing the highest mechanical strength and thermal stability up to 60 °C. Thixotropy tests demonstrated excellent structural recovery in (10BW OG)60-HG40, making it suitable for high-shear processes like batter mixing. Texture profile analysis showed that (10BW OG)60-HG40 and (10BW OG)40-HG60 had the highest hardness among gels, yet (10BW OG)60-HG40 yielded the softest sponge cake, indicating improved aeration and moisture retention. Color analysis indicated brighter crumb and crust in bigel-incorporated cakes, attributed to the high water content and reduced Maillard browning. Microscopy revealed that the highest wax-containing bigels formed dense crystalline networks, correlating with superior rheological and stability characteristics. Among all formulations, (10BW OG)60-HG40 and (3SW:7BW OG)40-HG60 stood out as the most promising palm oil replacers, offering a balance between structural integrity and thermal resistance. This study provides a novel fat replacement strategy by combining soy wax, beeswax, and citrus fiber, and demonstrates its practical functionality in low-fat sponge cake applications.Öğe Türü: Öğe , Evaluation of the Relationship between Video Head Impulse Test Findings and Vestibular Nerve Anatomical Measurements in Patients with Benign Paroxysmal Positional Vertigo(Istanbul University Press, 2026) Olgun, Burak; Güneş, Selçuk; Çelik, Mustafa; Şimşek, Baver Maşallah; Atasoy, Ercan; Kaya, Kamil Hakan; Aşaroğlu, Can BerkObjective: This study aimed to evaluate the relationship between video head impulse test results and vestibular nerve changes in patients with benign paroxysmal positional vertigo (BPPV). Material and Methods: Thirty-four patients (6 males, 28 females; age range 18-65) presenting with vertigo were included. All patients underwent contrast-enhanced magnetic resonance imaging to exclude cerebellopontine angle tumours. MRI measurements of the cerebellopontine angle, internal acoustic canal, vestibular nerve long and short axes, and cross-sectional area were performed. All participants underwent vHIT testing, and the results were compared between the affected and unaffected sides. Measurements were obtained in the axial plane aligned with the internal acoustic canal and performed by experienced radiologists. These findings were interpreted as reduced VOR gain rather than true semicircular canal hypofunction. Results: Ten patients had lateral semicircular canal involvement. Reduced VOR gain was observed in the affected canals. Twelve patients had anterior semicircular canal involvement, and 12 had posterior canal involvement. The vestibulo-ocular reflex (VOR) gains on the affected sides were lower compared to the unaffected sides (0.54-0.78 for affected canals and 0.84-0.98 for unaffected canals). However, there were no statistically significant differences in MRI measurements of the long axis of the vestibular nerve, short axis, or cross-sectional area between the affected and unaffected sides (p-values 0.836, 0.626, and 0.521, respectively). Conclusions: vHIT proved to be an effective and reliable method for detecting the affected semicircular canal in BPPV. Despite changes in VOR gains, there were no significant differences in the MRI measurements of the vestibular nerve between the affected and unaffected sides.Öğe Türü: Öğe , Neuroplasticity in Neurodegenerative Diseases(Peter Lang Publishing Group, 2026) Kaya Sağlam, Öznur; Yaşasın, Yusuf; Demir, Cansu; Gür Özmen, Selen[ No Abstract Available ]
