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Permanent URI for this collectionhttps://hdl.handle.net/20.500.14411/18
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Article SHAP-Guided Feature Selection for Cross-Dataset Generalization in Network Intrusion Detection Systems(IEEE, 2026) Şengül, Gökhan; Kılıç, CanFlow-based machine learning intrusion detection systems (IDS) often achieve near-perfect performance when trained and tested on a single benchmark dataset; nonetheless, their ability to generalize across datasets is a crucial and mostly unresolved challenge. This study analyzes the cross-dataset generalization behavior of an explainable, flow-based IDS trained on CICIDS2017 and externally evaluated on the CSE-CIC-IDS2018 dataset, which represents a more realistic network environment with varying attack implementations, traffic compositions, and background services. Two frequently used ensemble models, Random Forest and XGBoost, are trained solely on flow-level metadata without packet payload examination. After removing non-behavioral identifiers (Flow ID, Source IP, Destination IP, and Timestamp) and harmonizing feature schemas, the datasets are aligned into a unified 80-dimensional feature space extracted with CICFlowMeter. SHAP (TreeSHAP) is used to calculate global feature importance and create multiple explainability-driven feature subsets, such as model-specific Top-20 sets, a COMMON-10 intersection, and a UNION-30 superset. Although both models attain near-perfect accuracy and weighted F1-scores on CICIDS2017 (macro-F 1 ≈ 0.90 ), when evaluated on CSE-CIC-IDS2018, macro-F1 drops to 0.127 for Random Forest and 0.119 for XGBoost, despite high overall accuracy, indicating a strong bias toward majority classes under domain shift conditions. SHAP-guided feature reduction provides a measurable but limited improvement for Random Forest, increasing macro-F1 from 0.127 to 0.166, while an additional port-removal ablation further improves macro-F1 to 0.207. In contrast, no significant cross-dataset improvement is observed for XGBoost. An additional practical observation is that SHAP-guided feature rankings remain highly stable across sample sizes: class-balanced subsets of approximately 400 flows (50 samples per class) produce highly similar Top-20 rankings to those obtained from 10,000 flows (1250 samples per class), supporting the feasibility of computationally efficient explainability. Overall, the results show that explainability-driven feature analysis improves transparency, compactness, and feature prioritization; however, it does not fully resolve the broader distributional shift challenges that limit cross-dataset generalization in flow-based intrusion detection systems.Article Thermal and Optical Signatures of Einstein-Dyonic ModMax Black Holes with GUP and Plasma Modifications(Elsevier, 2026-05) Sakallı, İzzet; Sucu, Erdem; Dengiz, SuatWe explore the thermodynamic and optical properties of Einstein-Dyonic-ModMax (EDM) black holes (BHs) incorporating quantum gravity corrections and plasma effects. The ModMax theory promotes the classical Maxwell theory to a non-linear electrodynamics with a larger symmetry structure (electromagnetic duality plus conformal invariance), and provides dyonic BH solutions characterized by both electric and magnetic charges modulated by the nonlinearity parameter gamma. Using the Hamilton-Jacobi tunneling formalism, we derive the Hawking radiation spectrum and demonstrate how the Generalized Uncertainty Principle (GUP) modifies the thermal emission, potentially leading to stable remnants. Our analysis of gravitational lensing employs the Gauss-Bonnet theorem to compute light deflection angles in both vacuum and plasma environments, revealing strong dependencies on the ModMax parameter and plasma density. We extend this to axion-plasmon environments, uncovering frequency-dependent modifications that could serve as dark matter signatures. The photon motion analysis in plasma media shows how the exponential damping term e-gamma affects electromagnetic backreaction on spacetime geometry. We compute quantum-corrected thermodynamic quantities, including internal energy, Helmholtz free energy, pressure, and heat capacity, using exponentially modified entropy models. The heat capacity exhibits second-order phase transitions with critical points shifting as functions of gamma, indicating rich thermodynamic phase structures. The energy condition analysis shows that classical ModMax electrodynamics satisfies the null and weak energy conditions, while the observed near-horizon violations arise only after incorporating quantum-corrected entropy effects.Article Optimizing Drone-Based Humanitarian Relief in Post-Disaster Scenarios: A Hybrid MCDM and Maximum Coverage Approach(Springer Heidelberg, 2026-05-02) Vural, DanismentThis study proposes a novel hybrid decision-making framework that integrates expert-driven supply prioritization via the Stepwise Weight Assessment Ratio Analysis (SWARA) method with an operationally constrained Maximum Coverage Problem (MCP) model to optimize drone-based humanitarian logistics in post-disaster scenarios. Grounded in a real-world case study of the 2023 Kahramanmaraş earthquake, the model systematically elicits expert preferences to rank critical supplies such as food, medical items, and cold chain products, and embeds these weights directly into a constrained MCP formulation. The model incorporates drone-specific operational limits, including battery consumption, payload capacity, and round-trip feasibility, to ensure realistic deployment strategies. Results show that scenario configurations with four to five strategically located drone bases, each equipped with four to five drones, can increase the achieved priority-weighted delivered quantity by up to 35-40% compared to minimal base-drone configurations within the proposed model framework. Moreover, the proposed framework improves responsiveness by prioritizing urgent deliveries and supporting more timely allocation decisions under operational constraints. Unlike traditional MCP approaches that rely on static weights, this method offers a context-sensitive and scalable optimization model informed by field expertise. The findings underscore the potential of structured expert-based weighting combined with operational optimization to enhance the efficiency and responsiveness of drone-assisted disaster relief systems.Article Less Fear, Better Function: The Impact of Minimally Invasive Cardiac Surgery on Kinesiophobia and Functional Capacity Compared to Median Sternotomy(Frontiers Media SA, 2026-05-14) Can Karahan, Zehra; Ozdem, TayfunIntroduction The comparative impact of Minimally Invasive Cardiac Surgery versus median sternotomy on the interplay between peripheral muscle strength, kinesiophobia, and functional capacity remains unclear. This study compared these parameters in the early postoperative period.Methods Forty-six patients (30 Sternotomy, 16 Minimally Invasive Cardiac Surgery) were included in this prospective study. Peripheral muscle strength (handgrip and knee extension), functional capacity (30-Second Sit-to-Stand test), and kinesiophobia (Tampa Kinesiophobia Scale) were assessed preoperatively and on the postoperative 5th day.Results Both groups experienced a significant decline in postoperative muscle strength from baseline; however, there was no statistically significant difference between the groups regarding the magnitude of this decline (e.g., right handgrip p = 0.366, right knee extension p = 0.294). However, the Minimally Invasive Cardiac Surgery group demonstrated superior functional performance in the 30-Second Sit-to-Stand test (p = 0.008) and significantly lower increases in kinesiophobia scores compared to the sternotomy group (p = 0.008). A significant negative correlation was found between kinesiophobia and functional capacity (r = -0.311, p = 0.035).Conclusion Although Minimally Invasive Cardiac Surgery does not mitigate surgery-associated muscle strength decline, it offers a distinct advantage in preserving functional capacity by minimizing kinesiophobia. Functional limitations after sternotomy appear driven more by movement-related fear than muscle weakness. Consequently, rehabilitation strategies should integrate kinesiophobia management to optimize early mobilization and functional independence.Clinical trail registration ClinicalTrials.gov, identifier (NCT07172529).Article Global De-Democratization and Women’s Political Empowerment in the 2000s(Pergamon-Elsevier Science Ltd, 2026-07) Ertan, Senem; Keysan, Asuman ÖzgürSince 2000, democratic backsliding led to changes in the gender regime, a deterioration in gender equality, and a decline of women's empowerment demonstrated in many country studies and small-N comparisons. Given the lack of large-N cross-national analyses, this paper seeks to close the gap by examining the impact of dedemocratization on women's political empowerment by comparing 162 countries. The findings highlight that lower levels of democracy are associated with lower levels of women's political empowerment. Indeed, not only cross-national, but also within-country changes in democracy levels have substantial short-term and long-term effects on women's political empowerment. Although securing representative democracy with free political parties, free and fair elections, or an effective parliament is important to politically empower women, this study demonstrates that women's political empowerment is sustained in countries where the rule of law and participatory democratic rule are strongly consolidated.Article Development and Validation of the Athlete Food Insecurity Scale (AFIS)(MDPI, 2026-04-10) Yıldırım, Gonca; Baş, Murat; Çetiner, Özlem; Sünbül, ÖnderBackground/Objective: Athletes' dietary needs are influenced by the physiological demands of their sport, so the impacts of disrupted food access may vary from those experienced by the general population. This study aimed to develop and validate the Athlete Food Insecurity Scale (AFIS), a sport-specific tool designed to measure food insecurity in athletes. Materials and Methods: The study included 500 young adult athletes from 18 different sports disciplines. The sample was divided for exploratory factor analysis (n = 300) and confirmatory factor analysis (n = 200). Standard procedures for scale development were followed, including content validity assessment, construct validity testing, convergent validity analysis, and reliability evaluation. Results: The final 23-item scale demonstrated a four-factor structure including performance changes, coping strategies, basic nutritional needs, and physical access restraints. Factor loadings ranged from 0.344 to 0.956, item-total correlations from 0.513 to 0.781, and Cronbach's alpha coefficients from 0.827 to 0.937. Confirmatory factor analysis supported the modified model with acceptable fit indices (chi(2)/df = 2.41, RMSEA = 0.080, TLI = 0.900, CFI = 0.910), and standardized factor loadings ranged from 0.53 to 0.89 (p < 0.05). Subscale scores differed significantly across Household Food Security Survey Module food security categories, supporting convergent validity. Conclusions: The AFIS demonstrates strong psychometric properties and may provide a sensitive tool for identifying and monitoring sport-specific food insecurity among athletes.Article A Note on Hazard Rates of Systems Protected by a Block(Metrika, 2026-04-29) Eryilmaz, SerkanThis paper is concerned with the investigation of the properties of the hazard rate of the system protected by a block. By examining the characteristics of the hazard rate of the system supported by a protection block, a comparison is made with the redundancy method, according to the hazard rate. It is shown that the lifetime of the system supported by the protection block is larger than the lifetime of the system equipped with redundant system asymptotically in the hazard rate order. The extension of the results to a system with multiple components is also discussed for a consecutive k-out-of-n system.Article Reliability Evaluation of a System Protected by Blocks(IMA Journal of Management Mathematics, 2026-04-30) Eryilmaz, SerkanWe model the reliability of a system with a main component and two auxiliary components for protection, one active, the other on cold standby. The main component performs the system function. The auxiliary components are called protection blocks. The failure rate of the main component depends on whether it is protected or not. The blocks have their own constant failure rate, that is, their lifetimes are exponentially distributed. The reliability of such a system is obtained and the properties of its failure rate are investigated. A necessary condition is obtained to compare the cost-e¤ectiveness of single and two-block protection. Likewise, we obtain necessary conditions for comparing the e¤ectiveness of di¤erent three-component designs under the mean time to failure criterion. In this way, the work provides decision support for the designers of systems protected by blocks.Article The Effect of Tax Justice on Income Redistribution: Empirical Evidence from OECD Countries(Akademiai Kiado Zrt, 2026-03-30) Ozkok Cubukcu, Dilek; Unalan, GokhanIncome taxation is theoretically considered one of the most effective and widely used tools of public finance for correcting income inequality. However, its actual redistributive capacity varies significantly across countries and depends on the design of tax instruments. This study isolates the effects of taxation from transfers to examine whether justice-based tax instruments-such as progressive tax rates, minimum living allowance (MLA), and tax credits-enhance redistribution. To empirically assess these relationships, a dynamic panel dataset covering 38 countries (37 OECD members and Bulgaria) between 2005 and 2020 is constructed. The System GMM method is applied to estimate the model. On average, taxation accounts for 26% of total redistribution, and its effect is significantly enhanced by equity-oriented tax policies. A one-point increase in tax progressivity leads to a 0.731-point rise in redistribution (P < 0.01), and tax credits have a similarly significant positive effect (+0.266). In contrast, personal allowances and zero-rate brackets show no statistically meaningful impact. A 10-point increase in the MLA index leads to a 0.4-point reduction in redistribution, suggesting that applying horizontal equity (equal treatment across household types) may undermine efforts to improve vertical equity (reducing income inequality). These findings highlight the importance of designing targeted and fairness-driven tax instruments to strengthen the redistributive role of taxation, beyond dependence on transfer mechanisms.Article Rational Torsion on Hyperelliptic Jacobian Varieties(Wiley-VCH Verlag GmbH, 2026-04-01) Suluyer, Hamide; Sadek, MohammadIt was conjectured by Flynn that there exists a constant such that, for any integer , any , there exists a hyperelliptic curve of genus over with a rational -torsion point on its Jacobian. Lepr & eacute;vost proved this conjecture with . In this work, we prove that given an integer in the interval , , satisfying certain partition conditions, there exist parametric families of hyperelliptic Jacobian varieties with a rational torsion point of order . In particular, we establish the existence of such varieties for when is odd and for when is even. A few explicit applications of this result produce the first known infinite examples of torsion 13 when , torsion 15 when , and torsion 17,18,21 when . In fact, we show that infinitely many of the latter abelian varieties are absolutely simple.