Welcome to IKU Academic Digital Archive System
OpenAccess@IKU is Istanbul Kultur University's Academic Digital Archive System, established in June 2014 to digitally store and provide open access to academic and artistic outputs in line with international standards and intellectual property rights. The system includes various outputs such as articles, presentations, theses, books, book chapters, reports, encyclopedias, and works of art produced by the university's faculty members and students.
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Recent Submissions
Crank-Nicolson Method for the Chiral nonlinear Schrödinger Equation
(Institute of Physics, 2025) Wahyuningsih, Ester T.; Magdalena I.; AKKOYUNLU, CANAN
In this paper, we develop a finite difference scheme based on the Crank-Nicolson method for solving the chiral nonlinear Schrödinger (CNLS) equation, which describes the dynamics of nonlinear wave propagation with chirality effects. The CNLS equation supports two types of progressive wave solutions: bright solitons and dark solitons. The proposed Crank-Nicolson scheme is implicit, unconditionally stable, and achieves second-order accuracy in both space and time. To evaluate the accuracy of the method, numerical results are compared with exact analytical soliton solutions. Numerical simulations are presented for the propagation of single bright and dark solitons. The results demonstrate that the Crank-Nicolson method accurately preserves soliton structures, making it an effective tool for studying the dynamics governed by the chiral nonlinear Schrödinger equation. The study demonstrates the effectiveness of the Crank-Nicolson method in capturing the dynamics of chiral nonlinear wave propagation and lays the foundation for further exploration of chiral effects in quantum and optical systems.
An Investigation on the Vibrational Analysis, Molecular Structure and Interaction With the Cellulase Enzymes of the Cellulose I Alpha and Cellulose I Beta: Dft Calculations, Docking Simulations
(Chemical Society of Ethiopia, 2025) Demirag, Aliye Demet; Çelik, Sefa; Özel, Ayşen E.; AKYÜZ, SEVİM
Molecular docking is one of the most widely used techniques for simulating molecular interactions between molecules and forecasting the mode of binding and affinities between them. Due to the presence of structure-function relationship, in this study firstly, the molecular structures of the cellulose I(alpha) and I(beta) molecules were optimized and their most stable structures were determined by density functional theory (DFT) using B3LYP method with 6-31G(d,p) basis set. The vibrational wavenumbers of 1-ring, 2-ring, 3-ring, and 4-ring structures of cellulose I(alpha) and I(beta) were calculated using the same level of theory. Reliable vibrational assignments were made based on potential energy distribution (PED %) of the vibrational modes. The energy gap (Eg = ELUMO - EHOMO) of the cellulose Iα and cellulose Iβ was found to be 8.286 eV and 7.965 eV, respectively. To identify the molecular interactions between cellulose Iα and Iβ ligands and the cellulase enzymes, molecular docking studies were performed. The molecular docking results revealed the strong interaction of the cellulose Iα and Iβ with Endoglucanase enzyme (-6.4 and -6.3 kcal/mol, respectively), enzyme β-glucosidase (-5.3 and -5.2 kcal/mol, respectively), and Exoglucanase enzyme (-6.1 and -6.2 kcal/mol, respectively).
MOL, GÖKÇE
Arş. Gör.
Solving the Large-Scale Crew Pairing Problem in the Airline Industry Using the Column Generation Method
(Springer Science and Business Media Deutschland GmbH, 2025) MOL, GÖKÇE; ERMİŞ, MURAT
The commercial airline industry is highly competitive, and resources must be carefully managed to be sustainable. Of the many factors that affect operating costs, the two most important are fuel costs and crew pairing. Crew pairing is the strategic assignment of flight crews, including pilots, co-pilots, and flight attendants, to designated sequences of connected flights. This pairing should be done carefully to ensure a balance between cost-effectiveness and operational efficiency. This study focuses on developing an efficient model and solution approach for large-scale real-world problems by addressing the airline crew pairing problem. The primary goal of crew pairing is to minimize the total number of crews required to cover all scheduled flights achieved by grouping flights into pairings that maximize overall crew utilization. Crew pairing also aims to minimize unproductive crew time. In other words, efforts are made to reduce waiting times and deadheads, which is the time spent at the destination to rest between flights. Since flight safety is crucial in air transportation, all pairings must comply with regulations set by national/international civil aviation authorities and international agreements. These regulations set restrictions for pilots and flight attendants, such as duty hours, rest periods, and flight duration. Several approaches have been proposed in the literature to find an exact solution to the crew pairing problem. These approaches are generally suitable for smaller datasets where the number of aircraft and destinations is limited due to issues such as scalability and impracticality. This paper addresses this challenge using the column generation method, an effective technique for solving problems characterized by a large number of variables. In our study, real flight data from the narrow-body fleet of a large global airline is used. The proposed method outperformed in terms of computational efficiency and feasibility for larger datasets.
Fine Motor Function in Breast Cancer: Special Focus on Sensation
(Springer Nature, 2025) AKEL, BURCU SEMİN; EVRENDİLEK, HALENUR; HOŞBAY, ZEYNEP
After cancer treatment, women with breast cancer often experience immediate impairment in fine motor function. This can be due to chemotherapy-induced peripheral neuropathy (CIPN), muscle weakness or protective posture, lymphedema, fatigue, and stress. The loss of hand dexterity and sensory dysfunction can significantly influence the ability of cancer patients and survivors to function at work and at home. Unfortunately, this adverse effect in daily life may generally be overlooked while focusing on primary treatment for survival. Assessing somatosensory and fine motor skills is crucial for planning early intervention in the early stages of breast cancer. Education, including self-management strategies, exercise, and sensorimotor training, are the main methods for addressing sensory disturbances and fine motor skill impairment. Although the benefits of these methods are acknowledged, the strongest evidence is found only for physical exercise. Further research is needed to identify the most effective exercise modalities, optimal timing, and duration of interventions.