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 telif haklarına uygun olarak Açık Erişime sunar.
Güncel Gönderiler
Projected Drought Intensification in the Büyük Menderes Basin Under CMIP6 Climate Scenarios
(MDPI, MDPI AG, Grosspeteranlage 5, CH-4052 BASEL, SWITZERLAND, 2025) Rotbeei, Farzad; Nuri Balov, Mustafa; Safari, Mir Jafar Sadegh; Vaheddoost, Babak
The amplitude and interval of drought events are expected to enhance in upcoming years resulting from global warming and climate alterations. Understanding future drought events’ potential impacts is important for effective regional adaptation and mitigation approaches. The main goal of this research is to study the impacts of climate change on drought in the Büyük Menderes Basin located in the Aegean region of western Türkiye by using the outcomes of three general circulation models (GCMs) from CMIP6 considering two different emission scenarios (SSP2-4.5 and SSP5-8.5). Following a bias correction using a linear scaling method, daily precipitation and temperature projections are used to compute the Standardized Precipitation Evapotranspiration Index (SPEI). The effectiveness of the GCMs in projecting precipitation and temperature is evaluated using observational data from the reference period (1985–2014). Future drought conditions are then assessed based on drought indices for three periods: 2015–2040 (near future), 2041–2070 (mid-term future), and 2071–2100 (late future). Consequently, the number of dry months is projected and expected to elevate, informed by SSP2-4.5 and SSP5-8.5 scenarios, during the late-century timeframe (2071–2100) in comparison to the baseline period (1985–2014). The findings of this study offer an important understanding for crafting adaptation strategies aimed at reducing future drought impacts in the Büyük Menderes Basin in the face of changing climate conditions.
Migration and environmental sustainability: The mediating role of renewable energy and income
(SAGE PUBLICATIONS LTD, 1 OLIVERS YARD, 55 CITY ROAD, LONDON EC1Y 1SP, ENGLAND, 2025) Olanipekun, Ifedolapo Olabisi
Concern about climate change has drawn out the numerous influences of human activities on the environment. However, the role of migration in environmental quality has been conspicuously silent in the literature despite the increasing rate of cross-country migration. As the energy transition progresses, it is important to examine the interplay between migration, renewable energy, income, and environmental quality in 33 advanced countries using the latest dataset. With data from 2010 to 2023, the study applies the non-additive panel quantile regression to two models with different interaction terms. Results show asymmetric migration impacts on environmental degradation, while the effects of globalization are mostly negative. Renewable energy only reduces environmental degradation at higher levels. However, renewable energy development reduces the impact of migration for most quantiles, while income increases the impact of migration throughout. The study implies that policies might influence how migration will affect the environment. Income-related activities are channels through which migration affects environmental degradation, but clean energy development is a sustainable policy against climate change regardless of population gains. Therefore, dividends of migration can be drawn to increase capacity in green technology through increased green finance, innovations, research, and development, thereby resulting in green economic growth.
A Novel and Robust LSTM Model for Customer Churn Analysis Using Deep, Machine Learning, and Ensemble Learning: A Telecommunications Case
(ISTANBUL UNIV, Rektorlugu, Beyazit, Fatih, ISTANBUL 34452, Turkiye, 2025) Başarslan, Muhammet Sinan; Ünal, Aslıhan; Kayaalp, Fatih
Customer churn is an important issue in increasing both the long- and short-term revenues. If companies
identify customers’ churn behavior, they can prevent churn, ensure customer loyalty, and, in turn, gain
better financial returns. The telecommunications sector is a customer-oriented sector that requires
customer retention to survive in the market. In this sector, customer churn is observed at a high level.
In recent years, artificial intelligence-based customer churn analysis has been widely used to predict
customer churn behavior. In this study, a customer churn analysis was conducted using publicly shared
Telco telecommunications data. Predictive models were constructed using machine learning (LR, KNN,
SVM, DT, RF, ANN), ensemble learning (XGBoost, Majority Voting), and deep learning (LSTM) methods. In
addition, a 3-layered LSTM model was proposed. Accuracy (Acc), F1-score (F1), Precision (Prec), and Recall
(Rec) rates were used to evaluate the models. As a result, the novel 3-layered LSTM model achieved 91.90%
Acc, 91.49% Prec, 92.31% Rec, and 91.90% F1 values. The proposed model is competitive with the existing
models.
The asymmetric relationship between pollution, economic growth, urbanization, renewable energy consumption, and life expectancy in Ghana: a novel Quantile‑on‑Quantile analysis
(SPRINGER, VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS, 2025) Zhang, Wanli; Fumey, Michael Provide; Bekun, Festus Victor; Karikari, Frank Agyemang; Yeboah, Samuel Duku; Aboagye, Gifty Takyiwaa; Yeboah, Evans
This study investigates the determinants of life expectancy in Ghana, focusing on the efects of economic growth, environmental pollution, urbanization, and renewable energy consumption. The research employs a novel Quantile-on-Quantile (QQ) regression approach to capture the non-linear relationships and varying impacts across life expectancy levels. This method allows for a more detailed analysis of how these factors afect life expectancy across diferent population segments. The results show that GDP growth positively impacts life expectancy, especially in higher quantiles with more pronounced economic benefts. In contrast, CO2 emissions have a negative impact, particularly in lower quantiles, highlighting the vulnerability of certain population groups to environmental degradation. Urbanization presents mixed efects, with positive impacts in some cases and harmful in others, refecting the complex challenges of rapid urban growth. Renewable energy consumption consistently improves life expectancy, underscoring the importance of sustainable energy policies. The study concludes that targeted policies promoting inclusive economic growth, stronger environmental regulations, improved urban infrastructure, and expanded renewable energy use are essential for enhancing life expectancy in Ghana. These fndings provide crucial insights for policymakers aiming to bridge the gap between economic development and public health.
Comparative evaluation of the performance of orthodontic retainers using different surface protocols: an in vitro study
(SPRINGER LONDON LTD, 236 GRAYS INN RD, 6TH FLOOR, LONDON WC1X 8HL, ENGLAND, 2025) Kurnaz, Merve; Arslan Nazan, Ali; Eraydın, Feyza
This study aims to assess the in vitro durability of Nitinol retainers, manufactured using computer-aided methods with hydrophilic or superhydrophilic surfaces to reduce debonding, alongside a commonly used composite adhesive. The 112 lower incisor teeth were embedded in blocks in pairs. Retainer wires were made up of 0.018×0.018 inch Nickel Titanium
alloy(G4™ Nickel Titanium G&H Orthodontics, USA) by bending a robot arm. A total of 16 teeth(8 blocks) were used for each of the mentioned 7 groups Ni-Ti Retainer; Laser Textured Ni-Ti Retainer; Laser Texturing and Atmospheric Plasma Applicated Ni-Ti Retainer; Atmospheric Plasma Applicated Ni-Ti Retainer; Laser Texturing and Atmospheric Plasma Applicated Ni-Ti Retainer*2; Laser Texturing and Atmospheric Plasma Applicated Ni-Ti Retainer*3; SS-0.0018“(Morelli, Brazil). Transbond LR(3 M Unitek, California) was used. The shear bond strength tests were conducted. The Kruskal-Wallis H test was employed, pairwise comparisons followed by Dunn’s test with Bonferroni correction as a post hoc analysis. There was no statistically significant difference between the groups for maximum force and maximum stress(p>0.05). However, a significant difference was found in maximum elongation (p:0.0023). Pairwise comparisons highlighted significantly higher elongation values in the SS-0.0018” group. The stainless-steel wire demonstrated higher elongation values, which may offer clinical advantages in cases with higher occlusal forces and periodontal problems due to its material flexibility. Laser Texturing and Atmospheric Plasma Applied Ni-Ti Retainers exhibited higher test performance. Surface treatments applied to CAD/CAM retainers can provide an advantage by enhancing bond strength, potentially reducing the risk of debonding. These findings underline the importance of material selection and surface treatments in optimizing
fixed retention strategies for long-term clinical success.
