Recep Tayyip Erdoğan Üniversitesi Kurumsal Akademik Arşivi
DSpace@RTEÜ, Recep Tayyip Erdoğan 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
An open-source SPICE simulation suite for teaching the memristor: Standard inverter–OTA emulator with bloom-aligned laboratory exercises
(Wiley, 2026) Gül, Fatih
The memristor—the fourth fundamental two-terminal circuit element—has become a key building block of neuromorphic computing, in-memory analogue arithmetic, and hardware-rooted security primitives. Despite this prominence in research, fabricated memristive devices remain inaccessible to most undergraduate teaching laboratories, and the topic is therefore typically restricted to symbolic exposition. This paper presents an open-source pedagogical packaging of the well-established CMOS-inverter + integrating-capacitor + OTA memristor emulator topology, adopted as is from several prior reports since 2014. The contribution is a turn-key teaching package: a single plain-text SPICE netlist that runs unmodified under the open-source ngspice and the freely distributed LTspice; a Python post-processing pipeline; a closed-form first-order model that predicts the hysteresis lobe area from the integrating capacitance, the transconductance and the excitation amplitude, giving instructors an analytic marking target; three laboratory exercises with assessment rubrics scaling along Bloom-taxonomy levels Remember → Apply → Analyse, differentiated into a second-year and a third-year track; and a public release under the MIT License. Over the 1 – 100 kHz band, the emulator satisfies all three of Chua's signatures quantitatively: the v–i locus is pinched at the origin to within (Formula presented.) of the current amplitude, the lobe area decays as (Formula presented.) (measured log–log slope −1.000), and it grows as the cube of the excitation amplitude (slope +3.01). Measurements agree with the closed-form model to a constant 4.3% across four parameter sweeps. The package needs no licence, no fabricated device and no specialised CAD environment.
Machine learning-driven multi-objective optimisation of shape-memory programming parameters in 4D-printed PLA
(Elsevier, 2026) Hacıoğlu, Ayhan; Eryıldız, Meltem; Özkat, Erkan Caner
4D printing extends additive manufacturing by introducing time-dependent functionality through stimuli-responsive feedstocks such as shape-memory polymers (SMPs). In 4D-printed PLA, performance is governed by programming temperature, holding time, and recovery temperature, whose effects are reflected in recovery time, shape fixity ratio, and shape recovery ratio. This study combines a replicated 49-condition Latin-square design, machine-learning surrogate models, NSGA-II multi-objective optimisation, and experimental validation to identify a Pareto-optimal process window. Eight regression models were evaluated using leave-one-condition-out (LOCO) cross-validation with nested hyperparameter selection. The surrogates achieved LOCO R2 values of 0.973 (RMSE 7.29 s) for recovery time, 0.874 (1.17 percentage points, pp) for the shape fixity ratio, and 0.975 (4.31 pp) for the shape recovery ratio. The shape fixity ratio increased from 90.2% to 98.8% between 50 and 55 °C before plateauing, with no significant additional effect of holding time. NSGA-II identified a knee point at 67.5 °C programming temperature, 2.0 min holding time, and 80.0 °C recovery temperature, predicting a recovery time of 3.14 s, shape fixity ratio of 99.72%, and shape recovery ratio of 91.70%. Across five validation points, maximum absolute deviations were 0.36 s, 0.75 pp, and 3.82 pp for recovery time, shape fixity ratio, and shape recovery ratio.
Accident-based human reliability assessment of ship mooring Operations: An Entropy-SLIM framework
(Elsevier, 2026) Turna, İdris
Mooring operations are among the most hazardous activities in maritime transportation and continue to cause injuries and fatalities. Although accident investigation reports provide information on contributing factors, their use in human reliability assessment (HRA) remains limited. This study proposes an accident-informed framework to estimate human error probability (HEP) in ship mooring operations by integrating the Success Likelihood Index Method (SLIM) with the Entropy Weight Method (EWM). Thirty-five accident investigation reports were analysed to identify performance shaping factors (PSFs) associated with human error. The PSFs were transformed into an occurrence matrix, weighted using entropy analysis, and incorporated into SLIM to estimate HEP values for tasks. The execution-related mechanism (T6.1) yielded a slightly higher accident-informed HEP than the perception-related mechanism (T6.3) (6.42 × 10−4 vs. 5.67 × 10−4) and a higher frequency-based risk contribution index (0.0122 vs. 0.00738). Within Task T6, two main failure mechanisms were identified: execution-related failures associated with line handling and perception-related failures associated with hazard recognition. T6.1 represented the higher-priority mechanism within the analysed accident sample because it combined a slightly higher HEP with higher accident occurrence frequency. The findings support practical priorities for mooring safety, including coordinated command and execution, safe crew positioning, proper line handling, continuous situational awareness, and scenario-based onboard drills.
Uncovering the determinants of ship detention duration in the Black Sea Region: a hybrid Bayesian and association rule mining perspective
(Nature Research, 2026) Çakır, Erkan; Çelik Maşalacı, Burcu
This study examines the key determinants of ship detention duration under Port State Control (PSC) within the Black Sea Memorandum of Understanding (MoU) region, comparing pre-pandemic and pandemic inspection outcomes. Using 756 PSC detention cases retrieved from the Black Sea Information System, a Tree-Augmented Naïve Bayesian Network (TAN) and Association Rule Mining (ARM) were applied to identify both probabilistic dependencies and frequent co-occurrence patterns. The TAN analysis revealed that PSC Authority exerted the strongest influence on detention duration, with its impact increasing notably during the pandemic. ISM Code-related deficiencies also became more critical, while traditional technical deficiencies such as Fire Safety and Life-Saving Appliances declined in significance. ARM results further highlighted that ISM non-compliance on older Ro-Ro vessels, were closely associated with detentions longer than two days in Russian and Romanian ports. These findings underline the necessity of authority-specific, risk-based inspection strategies and improved standardisation of ISM audits to minimise operational disruptions. This study is the first duration-focused analysis for the Black Sea MoU using an integrated TAN + ARM framework.
Finite element investigation of TPMS-inspired microplate structures for mechanical stability enhancement in sports equipment
(Nature Research, 2026) Liu, Long; Liu, Long; Foong, Loke Ko; Yaylacı, Murat
The development of lightweight but impact-resistant sports gear needs structural ideas that boost mechanical stability while also keeping good energy uptake characteristics. Here, we do a finite element look into TPMS inspired multilayer microplate designs under dynamic input, like real-time excitation. We choose three different TPMS cores, Primitive, Gyroid, and I-graph, wrapped into what we call a Wrapped Package-graph, to see how they affect the nonlinear vibration behavior and the energy dissipation in sandwich-type microplates. The mechanical setup is built on Mindlin–Reissner plate theory, but we also add von Kármán-style geometric nonlinearity, so the model can capture the moderate to large deflection effects properly. For size-related trends, we use the modified strain gradient theory (MSGT), in which several material length-scale parameters are brought in to represent microscale deformation mechanisms in a more faithful way. Furthermore, the way the microplate interacts with its supporting medium is treated through a nonlinear elastic foundation, so the behavior stays close to the more realistic operating conditions you see in sports equipment. A full finite element setup is built, where the nonlinear part of the deviatoric stretch-gradient vector is slipped into the governing equations. Then the nonlinear system is handled in order to pull out transient responses, mode shapes, and how kinetic, potential, and overall energies change in time. After that, parametric checks are run to see how the TPMS topology, the excitation intensity, the foundation stiffness, the geometric dimensions, and those MSGT length-scale parameters affect the structural performance. The numerical findings show clear gaps between the P, G, and IWP architectures when it comes to vibration behavior and the ability to absorb energy. Especially, TPMS-based multilayer microplates seem to provide better dynamic steadiness, together with a higher elastic strain energy, which suggests they could be used in next-generation high-performance sports hardware under impact and vibration loading.
