WoS İndeksli Yayınlar Koleksiyonu

Permanent URI for this collectionhttps://gcris.khas.edu.tr/handle/20.500.12469/4465

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XY-Ashkin Phase Diagram in D=3
(Elsevier, 2025) Turkoglu, Alpar; Berker, A. Nihat
The phase diagram of the Ashkin-Tellerized XY model in spatial dimension d = 3 is calculated by renormalization-group theory. In this system, each site has two spins, each spin being an XY spin, that is having orientation continuously varying in 2 pi radians. Nearest-neighbor sites are coupled by two-spin and four-spin interactions. The phase diagram has ordered phases that are ferromagnetic and antiferromagnetic in each of the spins, and phases that are ferromagnetic and antiferromagnetic in the multiplicative spin variable. The phase diagram distinctively exhibits a pair of symmetrically situated direct bifurcation points and a pair of symmetrically situated reverse bifurcation points of the phase boundaries. The renormalization-group flows are in terms of the doubly composite Fourier coefficients of the exponentiated energy of nearest-neighbor spins.
Acoustic Assessment of Four Music Rehearsal Rooms in Accordance With ISO23591 Standard
(Elsevier Sci Ltd, 2025) Saher, Konca; Ozgencil, Yalin; Khoshkholghi, Solmaz
Optimizing rehearsal room acoustics is crucial for musicians to perceive sound, pitch, and frequency variations. Since the introduction of the international standard ISO 23591 Acoustic quality criteria for music rehearsal rooms and spaces, research in the field of music rehearsal rooms has significantly intensified. However, relatively few have adopted an approach that integrates both objective measurements and subjective user evaluations, particularly in rehearsal rooms for quiet-category instruments. Therefore, this study aimed to assess and improve the acoustical conditions of four Turkish rehearsal rooms for quiet-category instruments using measurements, simulations, and musician surveys. A survey conducted in the first phase revealed that musicians rated the efficiency, satisfaction, and frequency balance of four rehearsal rooms as bad to fair. Efficiency of rehearsals showed a strong correlation with frequency balance (R2 = 0.72 for low-to-mid; R2 = 0.76 for high-to-mid). Strong correlations (R2 = 0.93) were found between calculated and perceived low-to-mid frequency balance, while high-to-mid frequency balance showed weaker correlations (R2 = 0.36), suggesting possible sensitivity to low-frequency issues; though this did not consistently align with user satisfaction, indicating that additional perceptual factors play a role. Acoustic measurements show that existing reverberation time (RTmid) values for all rooms fall outside recommended limits. The measured rehearsal rooms were modeled, calibrated, and 36 acoustic models were developed with three alternative designs to improve acoustics within recommended limits. Then musicians from these rooms assessed 36 acoustic models through listening tests based on auralizations. Listening tests showed a preference for models with RTmid values within the recommended range, aligning subjective and objective assessments. After the RTmid value, effect of low-to-mid frequency balance was important in the choice of rooms for musicians.
Glaring and Out Loud! Thinking Women's Cinema in Turkey Through Agency and Companionship
(Routledge Journals, Taylor & Francis Ltd, 2025) Akcali, Elif; Guclu, Ozlem
Recognizing the 2010s as a decade that marks a shift in the audiovisual landscape in Turkey in terms of increased visibility of women and diversity of gender roles on screen, but most importantly as a decade of women filmmakers' rising voices, in this article, we aim to bring forward the significant strands and tendencies that define this period via a discussion of the representations of women marking a break and a difference from the past examples, and an evaluation of women filmmakers' ever growing involvement in the film industry and their solidarity networks. The data in this article was gathered within the work packages of a 26-month research project and it includes the insights, analyses and results drawn from quantitative and qualitative methods. In the following pages, we aim to reveal the diversified output of women filmmakers of the 2010s and to establish the extended boundaries of their filmmaking without setting hierarchies between mainstream, art-house, short, animation or documentary films. Marking this period as unique and ample in the history of cinema in Turkey, we aim to emphasize its novelties. We then turn to the statistical results of our research project and cross-read them with our interview data with an affirmative ethical approach.
Educational Researchers Perceptions of Editorial Ethics and Attitudes in Turkish Academic Journals: a Mixed-Methods Study
(BMC, 2025) Sertel, Gulsum; Karadag, Engin; Ciftci, S. Koza
This study aimed to determine editors' attitudes toward the article publication process in educational journals. A convergent mixed-methods design was employed to achieve this. Data were collected from 179 faculty members working in the education faculties in Turkey. The data collection instruments included the Editorial Attitudes Assessment Scale, a questionnaire on demographic characteristics, and an open-ended question soliciting additional opinions on the subject matter. The results of the descriptive and comparative analyses were compared, interpreted, and integrated with the findings obtained from the supplementary views provided by the participants. The authors contend that there are significant ethical shortcomings in the editorial practices. To enhance awareness of the role, responsibilities, and scientific and social obligations of editors in the article publication process, editorial training, orientation, and incentives for editing can be implemented.
A Methodological Approach to the Computational Problems in the Estimation of Adjusted Pin Model
(Routledge Journals, Taylor & Francis Ltd, 2025) Ersan, Oguz; Ghachem, Montasser
It is well documented that computational problems may lead to large biases in the estimation of probability of informed trading (PIN) models. The complexity of the AdjPIN model [Duarte, J. and Young, L., Why is PIN priced? J. Financ. Econ., 2009, 91, 119-138.], an extension of the conventional PIN model, exacerbates further these computational issues due to its larger parameter set. We introduce a dual approach to improve estimation reliability: a logarithmic factorization of the likelihood function and a strategic algorithm for generating initial parameter sets. The logarithmic factorization addresses floating point exceptions and numerical instability, while the algorithm significantly reduces the likelihood of converging to local maxima. We show that our methodology outperforms existing best practices and it enables accurate estimation of the AdjPIN model. We, therefore, strongly suggest its use in future studies.
Beyond the Quest for a Technological Holy Grail: Patterns of Income Inequality and the Household Carbon Footprint in Turkey
(Cambridge Univ Press, 2025) Gurer, Eren; Satioglu, Bingul; Voyvoda, Ebru; Yeldan, A. Erinc
Utilizing data on household consumption expenditure patterns and sectorial greenhouse gas emissions, we study the extent of inequality over Turkish households' differentiated carbon footprint incidences. We harmonize the household budget survey data of the Turkish Statistical Institute (TURKSTAT) with production-based gas emissions data from EXIOBASE3 and investigate both the direct and indirect emissions across household-level income strata. Our calculations reveal that the households in the highest income decile alone are responsible for 19.4 percent of the overall (direct and indirect) emissions, whereas the bottom 10 percent of households are responsible for 4.3 percent. We also find that for direct emissions, the per-household average of the highest income decile exceeds that of the lowest income decile by a factor of 11.2. Notably, 87 percent of the indirect emissions budget for the poorest decile is linked to food and housing expenses, underscoring their susceptibility to climate policies. We confer that in designing the net-zero emission pathways to combat climate change, it would not suffice to study the technological transition of decarbonization solely and that the successful implementation of an indigenous environmental policy will ultimately depend upon the socio-economic factors of income distribution strata, indicators of consumption demand, and responsiveness of the individual households to react to price signals.
Significant Reflection and Absorption Effects in the X-Ray Emission of the Intermediate Polar IGR J17195-4100
(Edp Sciences S A, 2025) Safak, Elif; Balman, Solen; Sala, Gloria
Context. X-ray emission is emitted from shock-heated plasma in magnetic cataclysmic variables, particularly in intermediate polars, and is processed by absorption and scattering before reaching the observer.Aims. We investigate these effects in the X-ray emission of the intermediate polar IGR J17195-4100 by carrying out the X-ray spectral analysis, and examining spin modulation and hardness ratio.Methods. We present high-sensitivity broadband X-ray spectral analysis by combining NuSTAR and XMM-Newton observations in the 0.3-78.0 keV energy range. X-ray spectral analysis is performed using six composite models, including the angle-dependent reflection model (reflect), multi-temperature plasma emission models (CEVMKL, MKCFLOW), and photoionised and/or neutral partially covering absorption models (zxipcf, pcfabs) within XSPEC. We also examine the spin modulation in four energy ranges and the hardness ratio to determine the absorption and scattering effects.Results. We find that the spectrum is best modelled with a reflection amplitude (Omega) of 0.58 -0.26+0.38 - 0.26 + 0.38 $ <^>{+0.38}_{-0.26} $ , an ionisation parameter, log(xi), of 1.46 -0.23+0.44 - 0.23 + 0.44 $ <^>{+0.44}_{-0.23} $ with an equivalent hydrogen column density of 3.09 -0.68+2.26 x 1022 - 0.68 + 2.26 x 10 22 $ <^>{+2.26}_{-0.68} \times 10<^>{22} $ cm-2, a neutral absorber, and a multi-temperature plasma temperature of 27.14 -2.13+2.0 - 2.13 + 2.0 $ <^>{+2.0}_{-2.13} $ keV. In addition, we detect effects of electron scattering in the NuSTAR band, leading to a modulation amplitude of approximately a steady 9%, which rises to 15% after 20 keV.Conclusions. We stress that these effects significantly affect the X-ray emission of intermediate polars and should be considered to obtain a good representation of the intrinsic spectrum.
Attentional Modulation of Outlier Processing
(Springer, 2025) Gokce, Ahu; Yildirim, Bugay; Boduroglu, Aysecan
Ensemble perception enables the visual system to function effectively when the number of stimuli in the environment exceeds its capacity. Ensemble representations not only help the limited capacity of visual representations, but they also facilitate the detection and representation of items deviating from the group (i.e., the outlier). This study focuses on how attentional mechanisms modulate outlier processing. In three experiments, we presented participants with an ensemble that was formed by circle stimuli in varying sizes, and the outlier item was distinct in terms of its location. We measured outlier localization performance while manipulating attentional orienting via a spatial cueing paradigm. In Experiment 1, a valid, invalid, or neutral cue was presented before or after the display. Facilitation of outlier localization was most pronounced in the valid precue condition. Experiment 2 included a task to actively engage ensemble perception in addition to outlier localization, and cue validity effect was observed as in Experiment 1. Experiment 3A was carried to directly compare the top-down and bottom-up influences on outlier processing by presenting two spatial outliers-one target and another distractor outlier. The target outlier identity was previously determined and was identical across trials. In Experiment 3B, the target was in red, making it salient among the remaining items. In the invalid trials, where the distractor outlier was cued, responses were closer to the distractor item indicating that outlier processing is cue driven. These experiments overall demonstrate that automaticity of outlier processing can be overridden by cue-driven processes.
Workplace Microaggressions Against LGBTI Plus Employees in Turkey: a Thematic Analysis of Environmental and Interpersonal Discrimination
(Emerald Group Publishing Ltd, 2025) Selen, Eser; O'Neil, Mary Lou; Ergun, Reyda
PurposeThe current study aimed to determine the extent and scope of microaggressions in the workplace directed towards LGBTI+ employees in Turkey.Design/methodology/approachThe research used both quantitative and qualitative data based on 664 statements made by individuals in the "The Situation of LGBTI+ Employees in the Private and Public Sector in Turkey" survey conducted between 2015 and 2020 (n = 2,695). The quantitative data consist of frequencies and the qualitative data center on answers to nine open ended questions regarding LGBTI+ individuals' experiences of discrimination in the workplace. We employed the taxonomy proposed by Nadal et al. (2010) to determine which actions constituted microaggressions and the form they took. We also conducted a critical discourse analysis of the open-ended questions where individuals described their experiences of microaggressions.FindingsMicroaggressions directed at LGBTI+ employees are pervasive in Turkey. Microaggressions largely follow the taxonomy created by Nadal et al. (2010) although we did not find microaggressions in all of the taxonomy's categories. We found that microaggressions mostly take the form of phobic language and mockery followed by heteronormativity, exoticization and disapproval. Two further categories, othering and threatening behaviors, emerged from our data.Originality/valueThis study addresses a significant gap in the literature on workplace microaggressions against LGBTI+ individuals, particularly in non-Western contexts. To our knowledge, it is the first study of its kind conducted in a non-Western Muslim-majority country. The research uniquely captures and critically analyzes the lived experiences of LGBTI+ employees through their own narratives, examining how microaggressions manifest as discriminatory discourses in the workplace.
Securing and Optimizing IoT Offloading With Blockchain and Deep Reinforcement Learning in Multi-User Environments (Vol 31, Pg 3255, 2025)
(Springer, 2025) Heidari, Arash; Navimipour, Nima Jafari; Jamali, Mohammad Ali Jabraeil; Akbarpour, Shahin
AI-Driven Predictive Maintenance for Workforce and Service Optimization in the Automotive Sector
(MDPI, 2025) Yildirim, Senda; Yucekaya, Ahmet Deniz; Hekimoglu, Mustafa; Ucal, Meltem; Aydin, Mehmet Nafiz; Kalafat, Irem
Vehicle owners often use certified service centers throughout the warranty period, which usually extends for five years after buying. Nonetheless, after this timeframe concludes, a large number of owners turn to unapproved service providers, mainly motivated by financial factors. This change signifies a significant drop in income for automakers and their certified service networks. To tackle this issue, manufacturers utilize customer relationship management (CRM) strategies to enhance customer loyalty, usually depending on segmentation methods to pinpoint potential clients. However, conventional approaches frequently do not successfully forecast which clients are most likely to need or utilize maintenance services. This research introduces a machine learning-driven framework aimed at forecasting the probability of monthly maintenance attendance for customers by utilizing an extensive historical dataset that includes information about both customers and vehicles. Additionally, this predictive approach supports workforce planning and scheduling within after-sales service centers, aligning with AI-driven labor optimization frameworks such as those explored in the AI4LABOUR project. Four algorithms in machine learning-Decision Tree, Random Forest, LightGBM (LGBM), and Extreme Gradient Boosting (XGBoost)-were assessed for their forecasting capabilities. Of these, XGBoost showed greater accuracy and reliability in recognizing high-probability customers. In this study, we propose a machine learning framework to predict vehicle maintenance visits for after-sales services, leading to significant operational improvements. Furthermore, the integration of AI-driven workforce allocation strategies, as studied within the AI4LABOUR (reshaping labor force participation with artificial intelligence) project, has contributed to more efficient service personnel deployment, reducing idle time and improving customer experience. By implementing this approach, we achieved a 20% reduction in information delivery times during service operations. Additionally, survey completion times were reduced from 5 min to 4 min per survey, resulting in total time savings of approximately 5906 h by May 2024. The enhanced service appointment scheduling, combined with timely vehicle maintenance, also contributed to reducing potential accident risks. Moreover, the transition from a rule-based maintenance prediction system to a machine learning approach improved efficiency and accuracy. As a result of this transition, individual customer service visit rates increased by 30%, while corporate customer visits rose by 37%. This study contributes to ongoing research on AI-driven workforce planning and service optimization, particularly within the scope of the AI4LABOUR project.
Event and Destination Image as Antecedents of Supportive Communication, Visit and Purchase Intentions
(Routledge Journals, Taylor & Francis Ltd, 2025) Uslu, Abdullah; Tosun, Petek; Al-Sulaiti, Khalid
Focusing on the Qatar 2022 FIFA World Cup, this study examined the impact of event image, subjective knowledge, and destination image on supportive communication and visit and purchase intentions. Structural equation modeling analyses on PLS-SEM were conducted following a consumer survey. The findings showed that the mega sport event's image and subjective knowledge of consumers regarding the event positively influenced destination image, positively affecting supportive communication intent, visit intentions, and the intention to purchase destination-origin products. Based on the image transfer and halo effect theories, this study extended previous findings by introducing subjective knowledge and purchase intentions into the event image-destination image-behavioral intentions framework. In alignment with the associate network memory model, the image transfer from the event to the destination significantly influences three behavioral intentions: supportive communication intent, visit intentions, and the intention to purchase the destination's products.
Sparse Deconvolution of Cell Type Medleys in Spatial Transcriptomics
(Public Library Science, 2025) Erdogan, Nuray Sogunmez; Eroglu, Deniz
Mapping cell distributions across spatial locations with whole-genome coverage is essential for understanding cellular responses and signaling However, current deconvolution models aim to estimate the proportions of distinct cell types in each spatial transcriptomics spot by integrating reference single-cell data. These models often assume strong overlap between the reference and spatial datasets, neglecting biology-grounded constraints such as sparsity and cell-type variations, as well as technical sparsity. As a result, these methods rely on over-permissive algorithms that ignore given constraints leading to inaccurate predictions, particularly in heterogeneous or unmatched datasets. We introduce Weight-Induced Sparse Regression (WISpR), a machine learning algorithm that integrates spot-specific hyperparameters and sparsity-driven modeling. Unlike conventional approaches that neglect biology-grounded constraints, WISpR accurately predicts cell-type distributions while preserving biological coherence, i.e., spatially and functionally consistent cell-type localization, even in unmatched datasets. Benchmarking against five alternative methods across ten datasets, WISpR consistently outperformed competitors and predicted cellular landscapes in both normal and cancerous tissues. By leveraging sparse cell-type arrangements, WISpR provides biologically informed, high-resolution cellular maps. Its ability to decode tissue organization in both healthy and diseased states highlights WISpR's practical utility for spatial transcriptomics, particularly in challenging settings involving noise, sparsity, or reference mismatches.
Advancing Image Spam Detection: Evaluating Machine Learning Models Through Comparative Analysis
(MDPI, 2025) Jamil, Mahnoor; Trpcheska, Hristina Mihajloska; Popovska-Mitrovikj, Aleksandra; Dimitrova, Vesna; Creutzburg, Reiner
Image-based spam poses a significant challenge for traditional text-based filters, as malicious content is often embedded within images to bypass keyword detection techniques. This study investigates and compares the performance of six machine learning models-ResNet50, XGBoost, Logistic Regression, LightGBM, Support Vector Machine (SVM), and VGG16-using a curated dataset containing 678 legitimate (ham) and 520 spam images. The novelty of this research lies in its comprehensive side-by-side evaluation of diverse models on the same dataset, using standardized dataset preprocessing, balanced data splits, and validation techniques. Model performance was assessed using evaluation metrics such as accuracy, receiver operating characteristic (ROC) curve, precision, recall, and area under the curve (AUC). The results indicate that ResNet50 achieved the highest classification performance, followed closely by XGBoost and Logistic Regression. This work provides practical insights into the strengths and limitations of traditional, ensemble-based, and deep learning models for image-based spam detection. The findings can support the development of more effective and generalizable spam filtering solutions in multimedia-rich communication platforms.
What Emotions Trigger the Perceived Destination Image and Word-of Recommendation in World Heritage Sites
(Wiley, 2025) Ferreira, Diana Filipa S.; da Costa, Rui Augusto; Chim-Miki, Adriana Fumi; Kozak, Metin
This study identifies what emotions trigger the tourism destination's perceived image and affect the word-of-mouth recommendation of World Heritage Sites. We used PLS-SEM and Multigroup Analysis. Data were collected from 271 tourists visiting Porto City, Portugal. Results show that not all emotions affect the destination's image. Deeper feelings require more time at the destination. Multigroup analysis indicated that the length of stay enhances the impact of emotional response on the perceived image of both positive and negative emotions. However, the number of repeat visits did not change the emotional response. Our results challenge the conventional wisdom in the field but underscore the dynamic nature of visitor-destination relationships. The findings reinforce the potential of emotional attachment to generate an emotional response that can influence visitor engagement. Destination managers can use these findings to optimize market positioning, improving both the destination image and enhancing positive word-of-mouth.
Effects of Imagining Someone Else Experience a Negative Autobiographical Memory on Phenomenological Experience
(Wiley, 2025) Donerkayali, Ceren; Ikier, Simay
We investigated whether the phenomenological experience of a negative autobiographical memory changes when the self is presumably distanced from it. In session 1, participants described and phenomenologically rated an important negative event. One week later, in session 2, they imagined and described the event as if either a similar or a dissimilar friend experienced it. Afterward, they once more rated the original event that they described in session 1. Results showed increased observer perspective and decreased vividness, accessibility, and reliving of the original event after imagining that a friend experienced it. Importantly, when the negative event was imagined as experienced by a friend, preoccupation with overwhelming emotions related to the event, the event's emotional intensity, and its centrality to identity and life story also decreased. When the imagined friend was dissimilar, the emotional valence of the memory became more positive, and the emotional distance to the memory increased.
Spatial Optimism in Individuals Future Thinking About the Covid-19 Pandemic
(Wiley, 2025) Oner, Sezin; Szpunar, Karl; Watson, Lynn Ann; Cole, Scott
Spatial optimism is the tendency to underestimate the severity of environmental threats in local relative to global contexts. We investigated whether spatial optimism was evident in people's beliefs about the estimated duration and severity of the COVID-19 pandemic. Participants from 15 countries provided estimates of (i) when the pandemic would be brought under control and (ii) infection rates for their country and globally. Overall, individuals estimated that the pandemic would end sooner and with a lower infection rate in their own country relative to the rest of the world. This spatial optimism bias was moderated by the severity of COVID-19 at the country level, such that the bias was greatest in countries with lower levels of pandemic severity. Findings parallel those observed for environmental threats and provide evidence for a spatial optimism bias in a distinct domain of collective thought. Implications for public-health messaging are discussed.
Fine Motor Tasks in Virtual Reality: the Impact of Haptic Feedback and Object Characterization
(IEEE-Inst Electrical Electronics Engineers Inc, 2025) Hatira, Nour; Sarac, Mine
Fine motor tasks in Virtual Reality (VR) are often constrained by the lack of natural sensory cues, particularly the sense of touch. Previous studies have shown that object characteristics (e.g., shape and size) influence how users perceive and interact with objects. However, the literature lacks insight into how these factors affect each other. This study investigates how different haptic feedback modalities and object characteristics influence user performance during fine motor tasks in VR. We conducted a user study with 25 participants as SenseGlove Nova 1 rendered alternative haptic feedback conditions: combined (force and vibration), force-only, vibration-only, and no feedback. Participants grasped and inserted virtual objects of different shapes (cube, cylinder, pentagon, triangle) and sizes (small, medium, large) into a toybox. Our results show that combined feedback consistently led to greater precision, fewer collisions, and an improved manipulation experience, particularly with larger and more complex objects. Object characteristics also significantly influenced performance: medium-sized and simpler-shaped objects created the best results. Additionally, object characteristics also influenced performance, with medium-sized and simpler-shaped objects leading to better performance. Our findings indicate the need to choose haptic feedback modalities based on object-specific characteristics for better user performance and experience.
Investigation of the Mechanical Strength of Cement Mortars Containing Novel Synthesised Chitosan/Hydromagnesite Stromatolite Nano-Composite
(Croatian Soc Civil Engineers-Hsgi, 2025) Karakus, Selcan; Ozbay, Ayse Elif Ozsoy; Pehlivan, Ahmet Onur; Yazgan, Ahmet Utku; Karapinar, Isil Sanri; Tasaltin, Nevin; Kilislioglu, Ayben
This study introduces the use of a novel synthesised chitosan/hydromagnesite stromatolite (CHT/HS) nano-composite in cement mortars and investigates its effects on the mechanical properties. The proposed bio-based nano-composite was synthesised by a green sonication method using HS originating from Salda Lake (Burdur, Turkey). The chemical and morphological properties of HS and CHT/HS nano-composites were determined. Specimens including HS in ratios of 5 and 10 % and CHT/HS nanostructures with 0.1, 0.5, 1 and 2 % were tested for flexural and compressive strengths for 7 and 28 days. The novel synthesised CHT/HS nano-composite showed a clear enhancement in mechanical strength. These findings suggest directions for future work on different nano-filler applications.
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Investigating the Role of the GTP-Cap in the Regulation of Microtubule Dynamics in Mammalian Cells
(Amer Soc Cell Biology, 2024) Cassidy, A.; Farmer, V.; Arpag, G.; Zanic, M.

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