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Permanent URI for this collectionhttps://hdl.handle.net/20.500.14288/3
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Publication Metadata only Validating digital traces with survey data: the use case of religiosity(Association for Computing Machinery, Inc, 2024) Department of Sociology;Department of Mathematics; Yörük, Erdem; Atsızelti, Şükrü; Yardı, Melih Can; Duruşan, Fırat; Etgü, Tolga; College of Social Sciences and Humanities; Graduate School of Social Sciences and Humanities; College of SciencesThis paper tests the validity of a digital trace database (Politus) obtained from Twitter, with a recently conducted representative social survey, focusing on the use case of religiosity in Turkey. Religiosity scores in the research are extracted using supervised machine learning under the Politus project. The validation analysis depends on two steps. First, we compare the performances of two alternative tweet-To-user transformation strategies, and second, test for the impact of resampling via the MRP technique. Estimates of the Politus are examined at both aggregate and region-level. The results are intriguing for future research on measuring public opinion via social media data.Publication Metadata only Vilma: a zero-shot benchmark for linguıstic and temporal grounding in video-language models(International Conference on Learning Representations, ICLR, 2024) Pedrotti, Andrea; Dogan, Mustafa; Cafagna, Michele; Parcalabescu, Letitia; Calixto, Iacer; Frank, Anetteh; Gatt, Albert; Department of Electrical and Electronics Engineering; Kesen, İlker; Erdem, Aykut; Department of Electrical and Electronics Engineering; Koç Üniversitesi İş Bankası Yapay Zeka Uygulama ve Araştırma Merkezi (KUIS AI)/ Koç University İş Bank Artificial Intelligence Center (KUIS AI); Graduate School of Sciences and Engineering; College of EngineeringWith the ever-increasing popularity of pretrained Video-Language Models (VidLMs), there is a pressing need to develop robust evaluation methodologies that delve deeper into their visio-linguistic capabilities. To address this challenge, we present VILMA), a task-agnostic benchmark that places the assessment of fine-grained capabilities of these models on a firm footing. Task-based evaluations, while valuable, fail to capture the complexities and specific temporal aspects of moving images that VidLMs need to process. Through carefully curated counterfactuals, VILMA offers a controlled evaluation suite that sheds light on the true potential of these models, as well as their performance gaps compared to human-level understanding. VILMA also includes proficiency tests, which assess basic capabilities deemed essential to solving the main counterfactual tests. We show that current VidLMs' grounding abilities are no better than those of vision-language models which use static images. This is especially striking once the performance on proficiency tests is factored in. Our benchmark serves as a catalyst for future research on VidLMs, helping to highlight areas that still need to be explored.Publication Metadata only Improving defocus blur in holographic displays(John Wiley and Sons Inc, 2023) Itoh, Yuta; Akşit, Kaan; Department of Electrical and Electronics Engineering; Kavaklı, Koray; Ürey, Hakan; Department of Electrical and Electronics Engineering; Graduate School of Sciences and Engineering; College of EngineeringIn this paper we present a novel multiplane computer generated hologram calculation approach that enables artifact free and realistic-looking defocus blur for optical reconstructions in a holographic display. We introduce a new targeting method and a loss function that evaluates the focused and defocused parts of the reconstructed images. We demonstrate that our method is applicable to various standard hologram generation routines such for both iterative and non-iterative CGH calculation methods. We also demonstrate our new gradient descent-based optimization with double phase constraint combined with our targeting scheme and loss function provides the best image quality. We validate our findings for both the numerical reconstructions and optical captures that are acquired from our holographic display prototype. © 2023, John Wiley and Sons Inc. All rights reserved.Publication Metadata only Team curie at HSD-2Lang 2024:hate speech detection in Turkish and Arabic tweets using BERT-based models(Association for Computational Linguistics (ACL), 2024) Hürriyetoğlu, Ali; Barkhordar, Ehsan; Topçu, Işık Sulal; Graduate School of Sciences and EngineeringThis study focuses on hate speech detection in Turkish and Arabic tweets using advanced BERT-based models. Performance metrics demonstrate the models' effectiveness, with the Turkish variant achieving a 71.8% F1 score and the Arabic model a 76.9% F1 score, ranking them fourth and third, respectively, in a competitive leaderboard. Performance enhancements were realized through targeted preprocessing, including emoji translation and user mention exclusion, and thoughtful data balancing approaches. Future directions include refining model accuracy and broadening language support. Our reproducible approach and detailed findings are accessible on GitHub.Publication Metadata only Inequality on the frontline: a multi-country study on gender differences in mental health among healthcare workers during the Covid-19 pandemic(Cambridge University Press, 2024) Czepiel, Diana; Mccormack, Clare; da Silva, Andrea T. C.; Seblova, Dominika; Moro, Maria F.; Restrepo-Henao, Alexandra; Martinez, Adriana M.; Afolabi, Oyeyemi; Alnasser, Lubna; Alvarado, Ruben; Asaoka, Hiroki; Ayinde, Olatunde; Balalian, Arin; Ballester, Dinarte; Barathie, Josleen A. l.; Basagoitia, Armando; Basic, Djordje; Burrone, Maria S.; Carta, Mauro G.; Durand-Arias, Sol; Fernandez-Jimenez, Eduardo; Frey, Marcela I. F.; Gureje, Oye; Isahakyan, Anna; Jaldo, Rodrigo; Karam, Elie G.; Khattech, Dorra; Lindert, Jutta; Martinez-Ales, Gonzalo; Mascayano, Franco; Mediavilla, Roberto; Gonzalez, Javier A. Narvaez; Nasser-Karam, Aimee; Nishi, Daisuke; Olaopa, Olusegun; Ouali, Uta; Puac-Polanco, Victor; Ramirez, Dorian E.; Ramirez, Jorge; Rivera-Segarra, Eliut; Rutten, Bart P. F.; Santaella-Tenorio, Julian; Sapag, Jaime C.; Seblova, Jana; Soto, Maria T. S.; Tavares-Cavalcanti, Maria; Valeri, Linda; Sijbrandij, Marit; Susser, Ezra S.; Hoek, Hans W.; van der Ven, Els; Department of Psychology; Eskin, Mehmet; Department of Psychology; College of Social Sciences and HumanitiesHealthcare workers (HCWs) were at increased risk for mental health problems during the COVID-19 pandemic, with prior data suggesting women may be particularly vulnerable. Our global mental health study aimed to examine factors associated with gender differences in psychological distress and depressive symptoms among HCWs during COVID-19. Across 22 countries in South America, Europe, Asia and Africa, 32,410 HCWs participated in the COVID-19 HEalth caRe wOrkErS (HEROES) study between March 2020 and February 2021. They completed the General Health Questionnaire-12, the Patient Health Questionnaire-9 and questions about pandemic-relevant exposures. Consistently across countries, women reported elevated mental health problems compared to men. Women also reported increased COVID-19-relevant stressors, including insufficient personal protective equipment and less support from colleagues, while men reported increased contact with COVID-19 patients. At the country level, HCWs in countries with higher gender inequality reported less mental health problems. Higher COVID-19 mortality rates were associated with increased psychological distress merely among women. Our findings suggest that among HCWs, women may have been disproportionately exposed to COVID-19-relevant stressors at the individual and country level. This highlights the importance of considering gender in emergency response efforts to safeguard women's well-being and ensure healthcare system preparedness during future public health crises.Publication Metadata only Wide-field-of-view dual-focal-plane augmented reality display(Spie-Int Soc Optical Engineering, 2019) N/A; N/A; N/A; Department of Electrical and Electronics Engineering; Başak, Uğur Yekta; Kazempourradi, Seyedmahdi; Ulusoy, Erdem; Ürey, Hakan; Master Student; PhD Student; Resercher; Faculty Member; Department of Electrical and Electronics Engineering; Graduate School of Sciences and Engineering; Graduate School of Sciences and Engineering; N/A; College of Engineering; N/A; N/A; N/A; 8579Stereoscopic augmented reality (AR) displays with a fixed focus plane suffer from visual discomfort due to vergence-accommodation conflict (VAC). In this study, we propose a biocular dual-focal plane AR system. Two separate liquid crystal displays (LCDs) are placed at slightly different distances to a Fresnel relay lens such that virtual images of LCDs appear at 25 cm and 50 cm to the user. Both LCDs are totally viewed by both eyes, such that the rendered images are not parallax images for each eye. While the system is limited to two depths, it provides correct focus cues and natural blur effect in two distinct depths. This allows the user to distinguish virtual information, even when the virtual objects overlap and partially occlude in the axial direction. Displays are driven by a single computation unit and the objects in the virtual scene are distributed over the LCDs according to their depths. Field-of-view is 60 x 36 degrees and the eye-box is larger than 100 mm, which is comfortable enough for two-eye viewing.Publication Metadata only Application-layer qos fairness in wireless video scheduling(IEEE, 2006) N/A; N/A; Department of Electrical and Electronics Engineering; Department of Electrical and Electronics Engineering; Department of Electrical and Electronics Engineering; Özçelebi, Tanır; Sunay, Mehmet Oğuz; Tekalp, Ahmet Murat; Civanlar, Mehmet Reha; PhD Student; Faculty Member; Faculty Member; Faculty Member; Department of Electrical and Electronics Engineering; Graduate School of Sciences and Engineering; College of Engineering; College of Engineering; College of Engineering; College of Engineering; N/A; N/A; 26207; 16372In mobile video transmission systems, the initial delay for pre-fetching video at the client buffer needs to be short due to buffer limitations and application-layer user convenience. Therefore, an effective cross-layer wireless design is required that considers both physical and application layer aspects of such a system. We present a cross-layer optimized multi-user video adaptation and scheduling scheme for wireless video communication, where Quality-of-Service (QoS) fairness among users is provided while maximizing user convenience and video throughput. Application and physical layer aspects are jointly optimized using a Multi-Objective Optimization (MOO) framework that tries to schedule the user with the least remaining playback time and the highest video throughput (delivered video seconds per transmission slot) with maximum video quality. Experiments with the IS-856 (1xEV-DO) standard and ITU Pedestrian A and Vehicular B environments show the improvements over today's schedulers in terms of QoS fairness and user utility.