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Double copy map for double field theory on an arbitrary constant background
No full textDouble field theory (DFT) can be constructed up to third order as the double copy of Yang-Mills theory. In this construction, one starts with Yang-Mills theory on Minkowski space and the resulting DFT action is also defined on Minkowski space. In this work, I extend this double copy procedure to obtain a DFT action on a constant DFT background starting from two Yang-Mills actions constructed around nontrivial background gauge fields on Minkowski space
Radikali birleştirmek: 1960’ların ortasından sonlarına Floransa ve ODTÜ mimarlık öğrencilerinin karşı pratikleri
No full textThis thesis is a transnational historical inquiry into the counter practices of architecture students from the Faculties of Architecture in Florence and METU against the prevalent architectural culture, pedagogical traditions, and sociopolitical climate of the 1960s. It examines the critical actions of the student groups in two different schools and geographies during the second half of the decade, when nonconformist architectural and social movements culminated all around the globe. Within this framework, it offers a close reading of how the Florentine and METU architecture students articulated their multifaceted radicalisms within the era’s student movements through collective and creative tangible outputs. Extending from subversive architectural projects, physical models, and spatial arrangements to political posters, collages, short films, and performances with objects, this study explores the students’ wide repertoire of radical responses to the status quo in multimedia forms. In doing so, it foregrounds the manifold processes in which students of both faculties imaginatively assembled different materials, objects, visuals, and texts to obtain dissenting hybrid compositions as distinct types of assembly/assemblage. Ultimately, taking the Florentine and METU contexts as two idiosyncratic examples of granular stories, this thesis aims to demonstrate how architecture students globally went beyond traditional protest models of the mid-to-late 1960s and physically expressed their dissent by creating the most collaborative, inventive, and critical forms of production within the period’s youth movements.Bu tez, Floransa ve ODTÜ Mimarlık Fakültelerindeki mimarlık öğrencilerinin 1960’ların egemen mimarlık kültürü, pedagojik düzeni ve sosyopolitik iklimine karşı geliştirdikleri pratikler üzerine ulusötesi bir tarihsel incelemedir. Çalışma, mimari ve toplumsal alandaki genelgeçer kabullere meydan okuyan hareketlerin etkisinin doruk noktasına ulaştığı 1960’ların ikinci yarısı bağlamında, bu iki farklı okul ve coğrafyadan öğrenci gruplarının eleştirel eylemlerini araştırır. Bu çerçevede, Floransalı ve ODTÜ’lü mimarlık öğrencilerinin özellikle kolektif ve yaratıcı somut çıktılar yoluyla dönemin öğrenci hareketleri içerisinde çok yönlü radikalliklerini nasıl ortaya koyduklarına dair detaylı bir okuma önerir. Radikal mimarlık projeleri, fiziksel maketler ve mekânsal düzenlemelerden; politik afişler, kolajlar, kısa filmler ve nesneler ile yapılan performanslara kadar uzanan geniş bir üretim repertuarı aracılığı ile öğrencilerin dönemin koşullarına karşı verdikleri çok biçimli tepkileri inceler. Bu bağlamda, iki fakültedeki öğrencilerin farklı malzemeleri, objeleri, görselleri ve metinleri yaratıcı şekilde birleştirerek muhalif melez kompozisyonlar üretme süreçlerini öne çıkarır. Tez, Floransa ve ODTÜ örneklerini detaylı ve bağlamsal okumalara imkân tanıyan iki kendine özgü durum olarak ele alarak, mimarlık öğrencilerinin dünya genelinde 1960’ların ortalarından sonlarına uzanan sürecin geleneksel protesto modellerinin ötesine geçtiğini ve dönemin gençlik hareketleri bağlamında tepkilerini en işbirlikçi, yaratıcı ve eleştirel üretim formları ile yansıttıklarını göstermeyi amaçlar.M.A. - Master of Art
Ağır petrol rezervuarları’nda farklı çözücü bileşimlerinin petrol geri kazanımına etkisi
No full textMiscibility is a critical factor in the effectiveness of CO₂-based Enhanced Oil Recovery (EOR). In many heavy oil reservoirs, CO₂ injection remains immiscible under reservoir conditions, which limits its ability to reduce viscosity and achieve efficient displacement. To overcome these challenges, lighter hydrocarbon solvents such as propane and butane have been proposed as alternatives, due to their lower Minimum Miscibility Pressures (MMPs) and stronger miscibility potential. The Batı Raman Field in Türkiye, a mature heavy oil reservoir suffering from natural production decline, provides a representative case study for evaluating these strategies. In this work, slim tube simulations using Eclipse 300 were employed to determine the MMP of propane and butane, while CMG GEM was used to perform field-scale reservoir simulations. The results show that propane injection at its MMP (1690 psi) achieved over 9% additional cumulative oil recovery, reduced oil viscosity by nearly 9%, and lowered the CO₂ MMP from 3527 to 3325 psi, enabling the potential for miscible CO₂ flooding in future operations. Economically, the normalized scoring method that combined NPV and IRR demonstrated that 0.1 PV propane injection delivered the strongest overall performance.Karışabilirlik, CO₂ esaslı Artırılmış Petrol Üretimi (Enhanced Oil Recovery, EOR) yöntemlerinin etkinliğinde kritik bir faktördür. Birçok ağır petrol rezervuarında CO₂ enjeksiyonu rezervuar koşulları altında karışabilirlik sağlayamadığından, viskoziteyi düşürme ve etkili yer değiştirme kabiliyetini sınırlar. Bu sorunu aşmak için, daha düşük Minimum Karışabilirlik Basıncına (MMP) ve daha güçlü karışabilirlik potansiyeline sahip hafif hidrokarbon çözücüler olan propan ve bütan alternatif olarak önerilmiştir. Türkiye’deki Batı Raman Sahası, doğal üretim düşüşü yaşayan olgun bir ağır petrol sahası olarak bu stratejilerin değerlendirilmesi için temsil niteliğinde bir örnek oluşturmaktadır. Bu çalışmada, propan ve bütanın MMP değerlerini belirlemek için Eclipse 300 kullanılarak slim tube simülasyonları gerçekleştirilmiş, saha ölçeğinde rezervuar simülasyonları için ise CMG GEM yazılımı kullanılmıştır. Sonuçlar, propan enjeksiyonunun kendi MMP’sinde (1690 psi) %9’un üzerinde ek kümülatif petrol üretimi sağladığını, petrol viskozitesini yaklaşık %9 oranında düşürdüğünü ve CO₂’nin MMP’sini 3527 psi’den 3325 psi’ye indirdiğini göstermiştir. Böylece gelecekte karışabilir CO₂ enjeksiyonu için potansiyel oluşturulmuştur. Ekonomik açıdan, NPV ve IRR’yi birleştiren normalize edilmiş skor yöntemi, 0.1 PV propan enjeksiyonunun en güçlü genel performansı sağladığını ortaya koymuştur.M.S. - Master of Scienc
Training-Free Affordance Labeling and Exploration using Subspace Projection and Manifold Curvature over Pre-Trained Deep Networks
No full textThe advancement in computing power has significantly reduced the training times for deep learning, enabling the rapid development of networks designed for object recognition. However, the exploration of object utility, the object's affordance, as opposed to object recognition, has received comparatively less attention. Existing object affordance models exhibit shortcomings, including limited robustness across diverse architectures and insufficient performance in complex environments. This work focuses on using pre-trained networks trained on object classification datasets to explore object affordances. While these networks have proven instrumental in transfer learning for classification tasks, the presented approach in this study diverges from conventional object classification methods by labeling affordances without modifying the final layers. Instead, pre-trained networks are employed to learn affordance labels without requiring specialized classification layers. Two approaches are tested: the Subspace Projection Method and the Manifold Curvature Method, which facilitate the determination of affordance labels without such modifications. Both the Subspace Projection Method and the Manifold Curvature Method were evaluated using nine distinct pre-trained networks across two different affordance datasets. The Subspace Projection Method achieved a True Positive Rate of up to 94% and 96% for the best-performing networks on each dataset, while the Manifold Curvature Method attained True Positive Rates exceeding 98% and 99% with its top-performing networks. Furthermore, both methods identify affordance labels that are not marked in the ground truth but are present in various cases. The robustness of the Manifold Curvature Method and the exploration capability of both methods highlight the effectiveness of proposed techniques for affordance labeling
Tartarik Asit Bazlı Sarmal Polimerlerin Sentezi ve Karakterizasyonu.
No full textStory of synthetic helical polymers has started with extreme abundance of helix motif in nature. This inspired scientists to replicate the helix motif in molecular level, and find potential application areas ranging from chiral recognition to circularly polarized light emitting devices. On the other hand, the number of ways of providing helicity is limited, and the helicity is generally provided by exploting side-chain interactions. To show that backbone chirality of a polymer can also provide helicity, three different polymers bearing tartaric acid-derived backbone with incorporation of chromophores have been synthesized and characterized by spectroscopic methods, including UV-Vis, fluorescence, IR and ECD. It has been shown that designed polymers exhibit helical conformations, and experimental findings were supported by molecular mechanics calculations.Sarmal yapıların doğada sıkça bulunması ve biyomoleküllerin fonksiyonlarını etkilemesi bilim insanlarını bahsedilen sarmal yapıların moleküler düzeyde taklit edilmesinin yanı sıra kiral algılama ve dairesel polarize ışık (circularly polarized light) saçan cihazlar gibi çeşitli uygulama alanlarında kullanılması konusunda teşvik etmiştir. Öte yandan, sentetik sarmal polimerlerde sarmallık çoğunlukla yan zincir etkileşimleri kullanılarak sağlanmaktadır. Bu bağlamda, polimerlerin omurga kiralitesinin de sarmallık katabileceğini göstermek adına, tartarik asit bazlı üç farklı polimer tasarlanmış ve sentezlenmiştir. Sentezlenen polimerler UV-Vis, floresans, IR ve ECD gibi spektroskopik yöntemlerle karakterize edilmiştir. Tasarlanan polimerlerin sarmal yapılara sahip olduğu gözlenmiştir ve deneysel gözlemlere ek olarak, polimerlerin sarmal yapıları moleküler mekaniksel hesaplar ile desteklenmiştir.M.S. - Master of Scienc
ERP/SAP ACCEPTANCE IN ORGANIZATIONS: A TAM- BASED MODEL GROUNDED IN SAP IS-U PRACTICES IN THE ENERGY SECTOR
No full textEnhancing lake water level forecasting with attention-based LSTM: a data-driven approach to hydrology and tourism dynamics
No full textIn recent decades, freshwater lakes in the Northern Hemisphere have faced significant challenges, including severe water shortages and increased stormwater discharges. As a result, accurate forecasting of lake water levels has become essential for effective water resource management, flood mitigation, and ecological sustainability—all of which are interconnected with dynamics in tourism within freshwater basins. This study evaluates the performance of an Attention-based Long Short-Term Memory (LSTM) model compared to a standard LSTM for predicting lake water levels over 5-day and 30-day intervals, utilizing five different input combinations at one of Hungary's popular tourist destinations Lake Velence. The results demonstrate that the Attention-based LSTM consistently outperforms the standard LSTM, particularly in long-term forecasting, as it effectively captures relevant temporal dependencies and reduces error accumulation. Additionally, a Pearson correlation analysis was performed to examine the relationship between guest nights and environmental factors, including lake water level, precipitation, temperature, and evapotranspiration. The findings reveal a strong correlation between guest nights and both temperature and evapotranspiration, while the associations with lake water level and precipitation are relatively weak. This indicates that climate conditions, rather than hydrological variations, primarily drive visitor numbers. The study highlights the importance of integrating advanced machine learning models in hydrological forecasting and tourism planning, providing valuable insights for sustainable water management and climate-adaptive tourism strategies
Cold War Design Diplomacy: Converging Paths of Raymond Loewy and the Middle East
No full textCold War Design Diplomacy:Converging Paths of Raymond Loewy and the Middle EastFatma [email protected] East
Technical UniversityTurkey's
foreign policy after World War II was strongly influenced by the Soviet threat,
prompting the country to strengthen its military, political, and economic
alliances with the West. This alignment was highlighted by Turkey's role as a
founding member of the International Monetary Fund (IMF) in 1947 and its
accession to the North Atlantic Treaty Organization (NATO) in 1952. In keeping
with this alignment, Turkey transitioned from a one-party regime to holding its
first multi-party elections in 1946. During the 1950s, the country experienced
rapid urbanization and housing challenges.U.S. Cold War foreign
policy aimed at containing communism and included support for economic development
in peripheral countries, with American designers playing major roles in various
overseas projects. Designers from Peter Müller-Munk Associates visited Turkey
in 1955, worked on local crafts, and established the Turkish Handicrafts
Development Office in Ankara in 1957. In 1954, Charles Abrams, a New York labor
lawyer and UN housing policy expert, visited Turkey to connect local housing
with the construction industry and global finance structures. However, Vecdi
Diker, the founding director of the Turkish National Highway Department,
suggested establishing a UN-supported technical university in Ankara, focusing
on training and education in housing and planning. G. Holmes Perkins from the
University of Pennsylvania served as the chief advisor for the establishment of
Middle East Technical University (METU), which was founded in 1956 as a
regional technical university with education in English. Perkins’ METU development
plan included a department of industrial design under the Faculty of
Architecture. Various efforts were made in the late 1950s and early 1960s to
establish the program. Between 1969 and 1972, David K. Munro, an American
industrial designer with extensive experience in overseas U.S. government
projects, worked at METU Faculty of Architecture. Munro opened elective courses,
curated an exhibition introducing the profession to the local audiences, and developed
a detailed curriculum for a graduate program in industrial design. The
department was officially established as a four-year undergraduate program in
1979.In 2001,
Professor Serim Denel of the California Institute of Technology visited her
alma mater, Middle East Technical University, in Ankara. Upon the invitation of
her colleague and master’s student, Güner Mutaf, she agreed to give a talk
about the early efforts to establish an industrial design program at METU.
During this informal gathering, Professor Denel recalled a surprising detail
from her student years: The world-famous designer Raymond Loewy had visited
METU in the winter of 1964, engaging with students in their studios and
conversing with them. The audience was left astonished—how could they not have
known about Loewy’s visit to Ankara? Why did he come? Additionally, why did he
send an issue of Industrial Design magazine to the Dean of METU Faculty of
Architecture, Aptullah Kuran, with a handwritten note in the margin
recommending Jay Doblin, the director of the IIT Institute of Design in
Chicago?The details of
Loewy’s trip to Turkey remained largely unknown until an improvised exploration
of the Raymond Loewy archives at the Hagley Museum and Library’s electronic
database revealed the entry “Box 6 United Nations, 1964-1968, ‘Report about the
Request of UN Assistance for the Establishment of a Department of Industrial
Design at the University of the Middle East in Ankara.’” Thanks to the
assistance of Hagley archivist Lucas R. Clawson, the author acquired scanned
copies of the documents under this entry. The paper reflects on the challenges
and the strategies developed in interpreting this “found” material including a
welcome letter from a UN TECABOARD representative in Ankara, receipts from the
Balin Hotel, a handwritten note on how to cook rice alla Turka, a private
telegram to Paris, handwritten notes on a “good speech’s secret,” and a brief
report about METU’s request of UN assistance. This unusual assemblage calls for
storytelling that connects these various pieces and reconstructs Loewy’s daily
adventures alongside his quasi-diplomatic business mission in Ankara. Content-wise,
two reports—one written by Dean Kuran of METU and the other by the UN design
diplomat Loewy—encourage a closer examination of the ideologies shaping the
narrative. Furthermore, Loewy’s handwritten speech notes, prepared for
introducing the story of the “newest of professions,” industrial design and its
role in “the economy and industrial life of America” to the audience at the
Ankara Chamber of Commerce, offer insights into the professional discourse of a
71-year-old Loewy. The paper discusses Loewy’s observations and insights about
industrial development in Turkey, the industrial stakeholders at the Ankara
Chamber of Commerce, and the ambitions of METU, and juxtaposes them with the
voices of local actors. The paper concludes with the methodological and
scholarly challenges involved in interpreting the archive material and proposes
alternative approaches to address them.
Keywords:
Cold War, Design Diplomacy, Raymond Loewy, Industrial Design, Middle East
Technical Universit
Dissecting Trends in the Latitudinal Diversity Gradient of Benthic Macroinvertebrates in Freshwater Lakes Across Scales
No full textThe latitudinal diversity gradient is one of the most striking biogeographical patterns on Earth and typically reveals increases in species richness from the poles towards the tropics. However, the latitudinal diversity patterns vary among taxa, ecosystems and scales. In freshwater, the patterns are particularly obscure, partially owing to limited geographical and taxonomical scope, as well as unclear controls of sampling effort. Here, we compiled data from a diverse group of benthic macroinvertebrates derived from standardised offshore surveys of 485 shallow freshwater lakes spread across the northern hemisphere to elucidate how diversity patterns at multiple spatial scales vary with latitude. At each scale, we calculated multiple effort-controlled measures emphasising different aspects of biodiversity. Contrary to our expectations, we found no evidence of a latitudinal gradient for any metric of diversity at small (local, α-) or large (regional, γ-) scales, nor any pattern of β-diversity among the lakes. Our results therefore provide some of the broadest evidence to date of a lack of latitudinal diversity gradient in offshore benthic macroinvertebrates in freshwater shallow lakes. Understanding this null relationship, and its contrast with many terrestrial and marine patterns, will require a concerted effort towards data compilation and comparative analyses
YPE’de Hazine Eurobondları Faiz Oranları ve Döviz Cinsinden Hazine Borcu
No full textThis paper studies the main determinants of the yield-to-maturity of Emerging Market
Economies (EMEs)’ Sovereign Eurobonds and emphasizes that not only the share of total
government debt in GDP but also its decomposition into foreign-currency-denominated and
domestic-currency-denominated debt matters for the yields to maturity in question. Indeed,
while an increase in the ratio of domestic-currency-denominated sovereign debt to GDP has no
significant effect on the yield to maturity of EMEs’ Sovereign Eurobonds, an increase in the
ratio of foreign-currency-denominated sovereign debt to GDP leads to a significant rise in the
yield to maturity of EME Sovereign Eurobonds. This significant effect of the foreign-currencydenominated Sovereign debt on the yield to maturity of EME Sovereign Eurobonds holds even
when we control for institutional quality in EMEs.Bu çalışma, Yükselen Piyasa Ekonomileri (YPE) hazineleri tarafından ihraç edilen Eurobondların
faiz oranlarını etkileyen etmenleri incelemektedir ve bu faiz oranlarının sadece devlet borcunun GSMH’ye
oranına değil, devlet borcunun YPE’nin ulusal paraları cinsinden mi yoksa döviz cinsinden mi olduğuna da
bağlı olduğunu vurgulamaktadır. Daha açık bir ifadeyle, YPE’nin ulusal para birimi cinsinden borçları
GSMH’ye oranla arttığında bu ülkelerin hazine eurobond faiz oranları anlamlı bir şekilde değişmezken,
YPE’nin döviz cinsinden borçları GSMH’ye oranla arttığında YPE hazine eurobond faiz oranları anlamlı
bir şekilde yükselmektedir. Döviz cinsinden borçların bahsi geçen etkisi YPE’deki kurumsal gelişmişlik
düzeyini kontrol etsek dahi anlamlı kalmaktadır.Publisher's Versio