Scopus İndeksli Yayınlar Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12416/8651
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Article Effects of Receiver Diversity on Bit Error Rate of Underwater Optical Wireless Communication Systems in Weak Oceanic Turbulence(Springer, 2025) Gokce, Muhsin Caner; Baykal, Yahya; Ata, YalcinThe receiver spatial diversity techniques are employed in underwater optical wireless communication (OWC) systems to mitigate oceanic turbulence, improving the bit error rate performance. In this paper, we consider an OWC system employing a binary phase-shift keying (BPSK) modulated Gaussian beam at the transmitter and employing receiver spatial diversity at the receiver. The techniques for receiver spatial diversity systems considered in the study are selection combining (SC), equal gain combining (EGC), and the maximum ratio combining (MRC). The bit error rate (BER) performance of the OWC system operating in weak oceanic turbulence is investigated by calculating the Gaussian beam's turbulence-induced scintillation index and the received optical intensity. It is found that the receiver spatial diversity techniques, especially EGC and MRC, are very effective for reducing the BER of an OWC system in weak oceanic turbulence. Furthermore, the BER performance of the underwater OWC system sees an improvement with an increase in the number of photodetectors or a decrease in the level of oceanic turbulence. Moreover, an improvement in the photodetector responsivity or a reduction in the system's noise factor contributes to achieving a favorable BER performance.Article Supply Chain Network Design Focused on Financial Measures and Performance Metrics: a Systematic Literature Review(Springer, 2025) Abbasi, Sina; Sicakyuz, CigdemThrough an extensive literature review, this study determines which metrics and measures are relevant for supply chain (SC) performance. We reviewed several universal papers published between 2012 and 2023. A selection of review papers was made according to the methods, contribution, and scope for measuring SC performance metrics and measures. By reviewing the literature, this survey prepares benchmarks and approaches for determining SC performance from a financial viewpoint. As core financial measures of SC performance, we investigation looked at inventory turnover ratios, logistics costs, and cash flows expressed as return on investment (ROI), return on equity (ROE), return on asset (ROA), profit margins, assets/liabilities, and working capital. Additionally, the study determined that key non-financial measures of SC performance are customer satisfaction, delivery performance, quality services, improved relationships, and competitive advantages. According to the study, the appropriate approaches for assessing SC performance are financial and non-financial measures. Using the same approach, measures, and metrics at all SC nodes is essential to determine SC performance appropriately. Moreover, research is needed to identify the benefits and issues preventing SC measurements and performance across different industries.Article Citation - WoS: 1Citation - Scopus: 1Prediction of the Profile of a Vertical Air-Entraining Vortex(Springer, 2025) Al-Hakeem, Yasameen Mansoor A.; Tastan, Kerem; Yildirim, NevzatAir-core vortices occurring at intakes cause efficiency losses, vibrations, operational difficulties, and erosion at affiliated water-conveying structures. Air-core vortices are in the forms of non-air entraining vortex (air-core vortex in suspension) and air-entraining vortex. The profile of an air-core vortex is considered to be one of the main characteristics of the vortex. There are available semi-empirical formulas for the profile of a vertical non-air entraining vortex (air-core vortex in suspension) occurring at a vertically-flowing downward intake. However, there is no available developed formula relating to the profile of a vertical air-entraining vortex occurring at a vertically-flowing downward intake because the height, radii, and other physical quantities of the imaginary section of the air-entraining vortex downstream of the intake entrance are not measurable. Therefore, the profile of a vertical air-entraining vortex needs to be predicted. In the present study, by modifying the available formula relating to the profile of a non-air-entraining vortex and incorporating available test data, a practical methodology is developed for predicting the profile of a vertical air-entraining vortex. This study provides a practical formula and a chart to determine the necessary parameters to predict the profile of a vertical air-entraining vortex. The validation of the proposed methodology is examined and checked with available test data relating to the profile of a vertical air-entraining vortex occurring at a vertically-flowing downward intake. The results of the present study are in good agreement with available test data relating to the profile of vertical air-entraining vortices (the coefficient of determination is between 0.976 and 0.995).Article Citation - WoS: 1Citation - Scopus: 1Fractional Systems With Multi-Parameters Fractional Derivatives(Springer, 2025) Muslih, S.I.; Agrawal, O.P.; Baleanu, D.Recently, a generalization of fractional variational formulations in terms of multiparameter fractional derivatives was introduced by Agrawal and Muslih. This treatment can be used to obtain the Lagrangian and Hamiltonian equations of motion. In this paper, we also extend our work to introduce the generalization of the formulation for constrained mechanical systems containing multi-parameter fractional derivatives. Three examples for regular and constrained fractional systems are analyzed. © The Author(s) 2025.Article Citation - Scopus: 4Ion-Acoustic Solitons in Magnetized Plasma Under Weak Relativistic Effects on the Electrons(Springer, 2023) Madhukalya, B.; Das, R.; Hosseini, K.; Baleanu, D.; Salahshour, S.Investigating ion-acoustic disturbances in a magnetized plasma, consisting of relativistic electrons and non-thermal ions, entails a comprehensive study into the nonlinear wave structure. By condensing the fundamental set of fluid equations for the flow variables, a singular equation known as the Sagdeev potential equation is derived using the pseudopotential approach. In this investigation of the magnetized relativistic plasma, we have observed only dip (rarefactive) (N< 1) soliton under both subsonic (M< 1) and supersonic (M> 1) conditions. The occurrence of the soliton depends on the wave velocities in different propagation directions. The magnitude of amplitudes of the relativistic solitons is higher for higher Mach number (M> 1) irrespective of the wave’s propagation direction. Furthermore, the magnitude of amplitudes of the solitary wave is seen to increase near the direction of the magnetic field. © 2023, The Author(s), under exclusive licence to Springer Nature India Private Limited.Article Citation - WoS: 1Citation - Scopus: 1Pure Bending of Fiber Reinforced Curved Beam at the Failure Limit(Springer, 2023) Farukoglu, Omer Can; Korkut, Ihsan; Motameni, AliThe purpose of this research is to study the limit failure stresses occurring on the rectangular cross section fiber reinforced curved beam subjected to couple moment at the ends of the geometry. Utilizing analytical methods, closed form solutions are obtained for plane stress conditions. Considering different parameters such as the radial thickness and fiber volume of the beam, stress and displacement fields are investigated in detail. Employing different failure criteria, Tsai-Wu and Norris, calculated failure limit moment and failure location differences in the beam are analyzed. Moreover, various transverse Young's modulus estimation methods available in the literature, Halpin-Tsai, Rule of Mixture, and Chamis, are considered. Effects of these estimations on the aforementioned fields are carefully handled as well. Using the material properties of glass fiber/epoxy constituents, numerical examples are generated by incorporating semi-analytical effective material property calculation models. Achieved numerical results have revealed that the radial thickness of the beam has more influence than fiber volume in terms of failure moment and stresses. Application of different criteria may cause different failure location acquisitions while mildly changing the limit failure moment. Young's modulus estimation influences the radial displacement prominently. In addition to the acquired results, from a general perspective, this study can be used as a benchmark model for failure stress analysis of related structures and may be expanded with appropriate numerical techniques.Article Citation - WoS: 5Citation - Scopus: 5Weighted Dynamic Hardy-Type Inequalities Involving Many Functions on Arbitrary Time Scales(Springer, 2022) El-Deeb, Ahmed A.; Mohamed, Karim A.; Baleanu, Dumitru; Rezk, Haytham M.The objective of this paper is to prove some new dynamic inequalities of Hardy type on time scales which generalize and improve some recent results given in the literature. Further, we derive some new weighted Hardy dynamic inequalities involving many functions on time scales. As special cases, we get continuous and discrete inequalities.Article Citation - WoS: 8Citation - Scopus: 9Bitcoin Price Prediction Using Sentiment Analysis and Empirical Mode Decomposition(Springer, 2025) Arslan, SerdarCryptocurrencies have garnered significant attention recently due to widespread investments. Additionally, researchers have increasingly turned to social media, particularly in the context of financial markets, to harness its predictive capabilities. Investors rely on platforms like Twitter to analyze investments and detect trends, which can directly impact the future price movements of Bitcoin. Understanding and analyzing Twitter sentiments can potentially provide insights into future Bitcoin price movements and can shed light on how investor sentiment affects cryptocurrency markets. In this study, we explore the correlation between Twitter activity and Bitcoin prices by examining tweets related to Bitcoin price sentiments. Our proposed model consists of two distinct networks. The first network exclusively utilizes historical price data, which is further decomposed into various components using the Empirical Mode Decomposition method. This decomposition helps mitigate the impact of irregular fluctuations on Bitcoin price predictions. Each of these components is then separately processed by Long Short-Term Memory (LSTM) networks. The second network focuses on modeling user sentiments and emotions in conjunction with Bitcoin market data. User opinions are categorized into positive and negative classes and are integrated with historical data to predict the next-day price using LSTM networks. Finally, the outputs of each network are combined to form the ultimate prediction values. Experimental results demonstrate that Twitter sentiment can effectively helps us predict Bitcoin price trends. Furthermore, to validate our proposed model, we compared it with several state-of-the-art methods. The results indicate that our approach outperforms these existing models in terms of accuracy. © 2025 Elsevier B.V., All rights reserved.Article Citation - WoS: 13Citation - Scopus: 11An Expanded Analysis of Local Fractionalintegral Inequalities Via Generalized (s,p)-Convexity(Springer, 2024) Li, Hong; Lakhdari, Abdelghani; Jarad, Fahd; Xu, Hongyan; Meftah, BadreddineThis research aims to scrutinize specific parametrized integral inequalities linked to 1,2, 3, and 4-point Newton-Cotes rules applicable to local fractional differentiable generalized (s,P)-convex functions. To accomplish this objective, we introduce a novel integral identity and deduce multiple integral inequalities tailored to mappings within the aforementioned function class. Furthermore, we present an illustrative example featuring graphical representations and potential practical applications.Article Citation - WoS: 1Citation - Scopus: 1Exchange Rate Volatility and Firms' Export Decisions: Evidence From Exporter Dynamics Database(Springer, 2024) Tunc, Cengiz; Solakoglu, M. NihatIn this paper, we study the effects of bilateral exchange rate volatility on the extensive margin of export. More specifically, we explore the effect of bilateral exchange rate volatility on the number of exporters, new entrants to the export market, and exiters from the market using destination and sector-specific export data of 28 developing countries from 1997 to 2014 provided by the Exporter Dynamics Database of the World Bank. The estimation results show that bilateral exchange rate volatility generates a depressing effect on the extensive margin of export. However, the effect is more significant for the entrants and minor for the exiters. Looking at the asymmetric effects with respect to currency depreciations versus appreciations, we find that more significant depreciations of currencies over longer horizons intensify the depressing effect of the volatility on the extensive margin. When we disentangle the destination countries as advanced and developing countries, we find that volatility displays a more significant asymmetric effect in the sample of developing destination countries.