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Permanent URI for this collectionhttps://hdl.handle.net/20.500.14288/6

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    PublicationOpen Access
    Ottoman literature as Mediterranean literature: travel, imperialism, and c omparison in Hac Yolunda by Cenab Şahabeddin
    (Mediterranean Institute, University of Malta, 2019) Department of Comparative Literature; Arslan, Ceylan Ceyhun; Faculty Member; Department of Comparative Literature; College of Social Sciences and Humanities; 280297
    The Mediterranean did not receive enough attention in research and scholarship on Ottoman literature, which has often been studied either as the precursor of modern Turkish literature or as a part of Islamic Middle Eastern literatures. Likewise, Ottoman literature did not receive significant attention in those branches of Mediterranean studies that have foregrounded interactions between Europe and the Maghreb. This article calls for an examination of representations of the Mediterranean in Ottoman texts, as well as the envisioning of Ottoman literature as Mediterranean literature. As a case study, I will be analysing a late Ottoman travelogue, the Hac Yolunda (On the Hajj Route; 1909) by Cenab Şahabeddin (1870–1934), a pioneering figure in Ottoman literature. I argue that the Mediterranean as a heuristic device can orient critics of Ottoman literature toward comparative and theoretical approaches that engage with fundamental debates in postcolonial studies and world literature.
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    PublicationOpen Access
    Dynamic accommodation measurement using Purkinje reflections and ML algorithms
    (Society of Photo-optical Instrumentation Engineers (SPIE), 2023) Department of Electrical and Electronics Engineering; N/A; Aygün, Uğur; Şahin, Afsun; Ürey, Hakan; Faculty Member; Faculty Member; Department of Electrical and Electronics Engineering; Koç University Research Center for Translational Medicine (KUTTAM) / Koç Üniversitesi Translasyonel Tıp Araştırma Merkezi (KUTTAM); College of Engineering; School of Medicine; N/A; N/A; N/A; 171267; 8579
    We developed a prototype device for dynamic gaze and accommodation measurements based on 4 Purkinje reflections (PR) suitable for use in AR and ophthalmology applications. PR1&2 and PR3&4 are used for accurate gaze and accommodation measurements, respectively. Our eye-model was developed in Zemax and matches the experiments well. Our model predicts the accommodation from 25cm to infinity (<4 diopters) with better than 0,25D accuracy. We performed repeatability tests and obtained accurate gaze and accommodation estimations using 15 subjects. We are generating a large synthetic data set using physically accurate models and machine learning algorithms.
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    PublicationOpen Access
    Computational selection of high-performing covalent organic frameworks for adsorption and membrane-based CO2 /H2 separation
    (American Chemical Society (ACS), 2020) Department of Chemical and Biological Engineering; Keskin, Seda; Altıntaş, Çiğdem; Harman, Hilal Dağlar; Aksu, Gökhan Önder; Researcher; Department of Chemical and Biological Engineering; College of Engineering; Graduate School of Sciences and Engineering; 40548; N/A; N/A; N/A
    Covalent organic frameworks (COFs) have high potential in gas separation technologies because of their porous structures, large surface areas, and good stabilities. The number of synthesized COFs already reached several hundreds, but only a handful of materials were tested as adsorbents and/or membranes. We used a high-throughput computational screening approach to uncover adsorption-based and membrane-based CO2/H2 separation potentials of 288 COFs, representing the highest number of experimentally synthesized COFs studied to date for precombustion CO2 capture. Grand canonical Monte Carlo (GCMC) simulations were performed to assess CO2/H2 mixture separation performances of COFs for five different cyclic adsorption processes: pressure swing adsorption, vacuum swing adsorption, temperature swing adsorption (TSA), pressure−temperature swing adsorption (PTSA), and vacuum−temperature swing adsorption (VTSA). The results showed that many COFs outperform traditional zeolites in terms of CO2 selectivities and working capacities and PTSA is the best process leading to the highest adsorbent performance scores. Combining GCMC and molecular dynamics (MD) simulations, CO2 and H2 permeabilities and selectivities of COF membranes were calculated. The majority of COF membranes surpass Robeson’s upper bound because of their higher H2 permeabilities compared to polymers, indicating that the usage of COFs has enormous potential to replace current materials in membrane-based H2/CO2 separation processes. Performance analysis based on the structural properties showed that COFs with narrow pores [the largest cavity diameter (LCD) < 15 Å] and low porosities (ϕ < 0.75) are the top adsorbents for selective separation of CO2 from H2, whereas materials with large pores (LCD > 20 Å) and high porosities (ϕ > 0.85) are generally the best COF membranes for selective separation of H2 from CO2. These results will help to speed up the engineering of new COFs with desired structural properties to achieve high-performance CO2/H2 separations.
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    PublicationOpen Access
    Energy and climate strategies, interests, and priorities of EU and Turkey
    (FEUTURE: The Future of EU-Turkey Relations, 2017) Colantoni, Lorenzo; Korkmaz, Dicle; Sartori, Nicolò; Schroeder, Mirja; Sever-Mehmetoğlu, Duygu; Department of International Relations; Yılmaz, Şuhnaz Özbağcı; Faculty Member; Department of International Relations; College of Administrative Sciences and Economics; 46805
    Energy is one of the sectors in which EU–Turkey cooperation could be most fruitful, possibly leading overall convergence through the common achievement of mutual interests in key areas – in particular, natural gas imports and diversification. Yet, this collaboration is undermined by the uncertainty over Turkey’s position vis-à-vis these policies and its undefined commitment to others, such as renewables and nuclear power; by doubts over the ability of the EU to balance security of supply, sustainability and competitiveness; and by the unclear growth trends of both regions. This situation is partially balanced by Turkey’s and the EU’s participation in several – sometimes successful – platforms for energy cooperation on the bilateral and multilateral levels (i.e. ENTSO-E, the European Network of Transmission System Operators for Electricity and MedTSO, the Association of the Mediterranean Transmission System Operators), which are aimed at the integration of the two polities’ energy markets. Nonetheless, the overall energy framework still needs a strong policy boost to set it on a common path towards convergence.
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    PublicationOpen Access
    Wearable multi-color RAPD screening device
    (Society of Photo-optical Instrumentation Engineers (SPIE), 2023) Department of Electrical and Electronics Engineering; Aygün, Uğur; Şahin, Afsun; Ürey, Hakan; Hasanreisoğlu, Murat; Kavaklı, Koray; Küçüködük, Abdullah; Faculty Member; Faculty Member; Faculty Member; Department of Electrical and Electronics Engineering; College of Engineering; School of Medicine; Koç University Hospital; N/A; N/A; 171267; 8579; 182001; N/A; N/A; N/A; N/A; N/A
    In this work, we developed a wearable, head-mounted device that automatically calculates the precise Relative Afferent Pupillary Defect (RAPD) value of a patient. The device consists of two RGB LEDs, two infrared cameras, and one microcontroller. In the RAPD test, the parameters like LED on-off durations, brightness level, and color of the light can be controlled by the user. Upon data acquisition, a computational unit processes the data, calculates the RAPD score and visualizes the test results with a user-friendly interface. Multiprocessing methods used on GUI to optimize the processing pipeline. We have shown that our head-worn instrument is easy to use, fast, and suitable for early-diagnostics and screening purposes for various neurological conditions such as RAPD, glaucoma, asymmetric glaucoma, and anisocoria.
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    PublicationOpen Access
    Koyunun olmadığı yerde keçiye Abdurrahman Çelebi derler: Ankara Eyaleti’nde Tiftik Keçisi ekonomisinin zaman-uzamsal analiz denemesi (1889-1905)
    (Vehbi Koç Ankara Studies Research Center (VEKAM) / Vehbi Koç Ankara Araştırmaları Uygulama ve Araştırma Merkezi (VEKAM), 2018) Department of History; Çelik, Semih; Department of History; College of Social Sciences and Humanities
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    PublicationOpen Access
    Söylem, temsil, faillik ve anlatı: yeni yoksulluk literatürünün bir eleştirisi
    (Denta Florya ADSM Limited Company (DENTAWORLD), 2017) Department of Sociology; Yörük, Erdem; Faculty Member; Department of Sociology; College of Social Sciences and Humanities; 28982
    In this article, a theoretical critique of the new poverty concept is presented. The New poverty concept has been increasingly used in the fields of development and social policy and it refers to a new stratum in the society. In this article, the new poverty concept is analysed in the light of the work of Michael Foucault, Edward Said, Ranajit Guha and Margaret Somers and a critique of the new poverty literature is presented using the theoretical framework regarding the concepts of discourse, representation, agency and narrative. As a result of this critique, it is emphasized that the non-critical use of the new poverty concept bears the risk of reconstructing the aforementioned population as a passive and victimised group.
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    PublicationOpen Access
    Sheep go to heaven, (Angora) goats go to hell: a spatio-temporal analysis of Angora Goat economy in the Province of Ankara (1889-1905)
    (Vehbi Koç Ankara Studies Research Center (VEKAM) / Vehbi Koç Ankara Araştırmaları Uygulama ve Araştırma Merkezi (VEKAM), 2018) Department of History; Çelik, Semih; Department of History; College of Social Sciences and Humanities
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    PublicationOpen Access
    Artificial eye model and holographic display based IOL simulator
    (Society of Photo-optical Instrumentation Engineers (SPIE), 2023) N/A; Department of Electrical and Electronics Engineering; N/A; Şahin, Afsun; Ürey, Hakan; Aygün, Uğur; Kavaklı, Koray; Akyazı, Deniz; Faculty Member; Faculty Member; Department of Electrical and Electronics Engineering; School of Medicine; College of Engineering; Graduate School of Sciences and Engineering; 171267; 8579; N/A; N/A; N/A
    Cataract is a common ophthalmic disease in which a cloudy area is formed in the lens of the eye and requires surgical removal and replacement of eye lens. Careful selection of the intraocular lens (IOL) is critical for the post-surgery satisfaction of the patient. Although there are various types of IOLs in the market with different properties, it is challenging for the patient to imagine how they will perceive the world after the surgery. We propose a novel holographic vision simulator which utilizes non-cataractous regions on eye lens to allow the cataract patients to experience post-operative visual acuity before surgery. Computer generated holography display technology enables to shape and steer the light beam through the relatively clear areas of the patient’s lens. Another challenge for cataract surgeries is to match the right patient with the right IOL. To evaluate various IOLs, we developed an artificial human eye composed of a scleral lens, a glass retina, an iris, and a replaceable IOL holder. Next, we tested different IOLs (monofocal and multifocal) by capturing real-world scenes to demonstrate visual artifacts. Then, the artificial eye was implemented in the benchtop holographic simulator to evaluate various IOLs using different light sources and holographic contents.
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    PublicationOpen Access
    Revealing the effect of structure curations on the simulated CO2 separation performances of MOFs
    (Royal Society of Chemistry (RSC), 2020) Velioğlu, Şadiye; Department of Chemical and Biological Engineering; Keskin, Seda; Faculty Member; Department of Chemical and Biological Engineering; College of Engineering; 40548
    Experimentally reported metal organic frameworks (MOFs) may have structural issues such as the presence of solvent molecules in their pores, missing hydrogen atoms in the frameworks and/or absence of charge balancing ions, which all require curation of structures before using them in molecular simulations. The development of computation-ready MOF databases significantly accelerated the assessment of CO2 adsorption by providing directly usable, curated crystal structures for molecular simulations. Each database followed different methods to curate MOFs which caused the same material to be reported with different structural features in databases. In order to understand the role of curated computation-ready MOF databases in the predicted CO2 separation performances of MOFs, we studied various MOFs commonly existing in databases but curated differently in terms of (i) removal of bound solvents, (ii) treatment of missing hydrogens, and (iii) retention of charge balancing ions (CBIs). We used molecular simulations to compute CO2/CH4, CO2/H2, and CO2/N2 mixture adsorption and predicted various separation performance metrics such as selectivity, regenerability (R%), and the adsorbent performance score (APS) for the curated computation-ready MOFs. Our results showed that the CO2 separation performances of MOFs and the identity of the best performing MOFs significantly change depending on the structure curation. For example, removal of coordinated solvents from MOFs resulted in higher simulated CO2 uptakes, selectivities, and APSs compared to the structures having solvents. On the other hand, the absence of CBIs in the frameworks resulted in overestimated CO2 uptakes, APSs, and R%, and underestimated CO2 selectivities compared to MOFs having CBIs. Based on these results, we suggested a path showing how to use the curated, computation-ready MOF structures in highthroughput molecular simulations.