OpenMETU (Middle East Technical University)
Not a member yet
110280 research outputs found
Sort by
Beyond borders: Exemplary culturally diverse policy practices within early childhood teacher education
No full textASSESSING ADVANCED RETRIEVALAUGMENTED GENERATION TECHNIQUES FOR QUESTION ANSWERING: A CASE STUDY ON GOVERNMENTAL SERVICES
Get PDFThis case study evaluates advanced Retrieval-Augmented Generation (RAG) methods to enhance
question answering in conversational AI for government services, focusing on data from the Ministry of
Health and Prevention. It assesses various RAG strategies like naive RAG, HyDE, Hybrid RAG,
Corrective RAG, Self RAG, and Astute RAG to tackle issues like hallucinations and reasoning gaps. The
study's methodology includes three phases: benchmarking embedding models, testing LLMs, and
evaluating RAG pipelines. Results show Astute RAG excels in improving accuracy and context
alignment, providing insights for optimizing AI solutions in government and healthcare, while
highlighting limitations in dataset and evaluation methods.M.S. - Master Of Science Without Thesi
Odometride Bilgi Füzyonu için Lie Cebirine Dayalı Çoklu Durum EKF Tasarımı
No full textRigid transformations or rotation matrices, which inherently do not belong to any vector space, are frequently encountered in state estimation. However, many state estimation frameworks are designed to operate on vector spaces. This thesis explores the application of Lie Algebra to effectively handle rigid transformations within state estimation. Specifically, it examines methods for expressing the uncertainty associated with rigid transformations and for differentiating nonlinear functions with respect to rotation matrices. As a key contribution, an augmented state extended Kalman filter is developed to integrate incremental pose information derived from a stereo camera setup with inertial measurements. The proposed framework is evaluated using the publicly available KITTI dataset. Experimental results demonstrate the effectiveness of the fusion in obtaining more accurate trajectory estimation.Konum ve yönelim bilgisi, matematiksel olarak, SE(3) grubu olarak tanımlanır. Gruplar, çoğu zaman vektörel bir uzay oluşturmazlar. Ancak, geleneksel durum kestirimi yöntemleri, kestirilen durumun vektörel bir uzay oluşturduğu varsayımına dayanarak tasarlanmıştır. Bu tez kapsamında, Lie cebiri kullanarak, konum ve yönelime ait hatayı ve belirsizliği nasıl tanımlayabileceğimizi inceliyorum. Dahası, bu tanım üzerine inşa edilmiş çoklu durum Kalman filitresi tasarlıyorum. Tasarladığım filitrenin amacı, ikili kamera düzeneğinden gelen ardışık görüntüler arası göreceli konum bilgisi ile ataletsel sensörden gelen ölçümleri birleştirerek daha hassas ve gürbüz bir şekilde konum ve yönelim kestirimi sağlamaktır. Öne sürdüğüm yöntemi, KITTI verisetinde test ederek, tasarlanan filitrenin amacını yerine getirdiğini gösteriyorum.M.S. - Master of Scienc
3D printed PCL-nHAp composite implants for the treatment of segmental bone defects: in vivo application in a rabbit model
Get PDFThe management and treatment of long bone defects are challenging clinical problems. In this study, in order to address the need for load bearing implants for segmental defects, 3D printed cylindrical implants of poly(caprolactone) (PCL) and nanohydroxyapatite (nHAp) composites were prepared and applied as lateral segments to the femurs of New Zealand white rabbits. The results of PCL-nHAp implant group obtained 6 weeks after the procedure were compared with those of the autografts. There was no significant difference between the yield and ultimate loads of autograft group and the implant group. Histological studies demonstrated similar new bone formation in both groups. Also, a sizeable callus formation around the autografts and bone ingrowth to the 3D printed implants were observed, and x-ray studies confirmed the formation of the callus. An increase was detected in the bone density around the defect site for both test groups. SEM revealed close interaction between the newly formed bone tissue and the struts of the 3D printed implant. mRUST values, which is an indicator of tissue healing, increased continuously during 6 weeks. In conclusion, 3D printed, 1.5 cm long cylindrical nHAp-PCL implants exhibited excellent bone healing and biomechanical stability in the large lateral segmental bone defects of the rabbits even in a relatively short implantation time as 6 weeks. We believe that these implants could serve as an alternative to autografts in the treatment of long bone defects
Türkiye ve Avrupa'daki Kuş Komünitelerinin Çeşitliliği ve Stabilitesi
No full textBiodiversity is essential for functioning of ecosystems and human existence. However, human activities have driven an unparalleled loss of biodiversity globally. Despite their ecological importance, birds are among the most impacted organisms, with 12% of all species facing extinction. In this thesis, I adopted a trait-based approach and used breeding bird atlases alongside generalized linear mixed-effect and spatial error models to examine (i) how extensive wetland degradation in central Türkiye has altered diversity of breeding wetland bird communities across spatial scales (ii) the extrinsic and intrinsic factors driving the temporal stability of breeding bird communities in Europe. Results showed that the decline in functional diversity of wetland birds in central Türkiye was stronger than taxonomic declines, with widespread species losses making communities taxonomically and functionally more heterogenous in space. Additionally, advancing seasonal shrinking/drying of wetlands likely threatens late-breeding endangered wetland birds in the region. Analyses concerning the community stability of European breeding bird communities revealed that extrinsic factors such as mean elevation, proportion of protected areas, biome coverage, and climate change significantly influenced taxonomic and functional stability. Communities with taxonomically or functionally similar neighbors remained more stable. Several intrinsic factors, including species richness and specific aspects of functional diversity, including redundancy, were also significantly associated community stability. The findings presented in this thesis can help guide conservation efforts, provide insight into the factors shaping stability of bird communities, and establish a foundation for future studies aiming at predicting vulnerability of communities to compositional and functional changes.Biyoçeşitlilik, ekosistemlerin işleyişi ve insan varlığı için hayati öneme sahiptir. Ancak, insan faaliyetleri küresel ölçekte eşi görülmemiş bir biyoçeşitlilik kaybına neden olmaktadır. Kuşlar, ekolojik önemlerine rağmen en fazla etkilenen organizmalar arasındadır ve tüm kuş türlerinin %12’si yok olma tehlikesi altındadır. Bu tezde, fonksiyonel bir yaklaşım benimseyerek, üreyen kuş atlaslarını, genelleştirilmiş lineer karma-etki ve mekânsal hata modelleri ile birlikte kullanarak (i) Türkiye’nin iç kesimlerindeki yaygın sulak alan tahribatının üreyen sulak alan kuş topluluklarının çeşitliliği üzerindeki farklı mekânsal ölçeklerde etkilerini, (ii) Avrupa’daki üreyen kuş komünitelerinin zamansal stabilitesini belirleyen dışsal ve içsel faktörleri inceledim. Sonuçlar, Türkiye’nin iç kesimlerindeki sulak alan kuşlarının işlevsel çeşitliliğindeki azalmanın taksonomik düşüşlerden daha güçlü olduğunu ve yaygın tür kayıplarının komüniteleri mekânsal olarak daha heterojen hale getirdiğini gösterdi. Ayrıca, sulak alanların mevsimsel olarak daha erken kurumasının, geç üreyen tehlike altındaki sulak alan kuşlarını tehdit ediyor olabileceği tespit edildi. Avrupa’daki üreyen kuş topluluklarının stabilitesi üzerine yapılan analizler, ortalama yükselti, korunan alan oranı, biyom kapsamı ve iklim değişikliğinin taksonomik ve fonksiyonel stabiliteyi önemli ölçüde etkilediğini ortaya koydu. Taksonomik veya fonksiyonel olarak benzer komşulara sahip komüniteler daha stabil kaldı. Tür zenginliği ve belirli fonksiyonel çeşitlilik bileşenleri gibi bazı içsel faktörlerin de topluluk stabilitesinin ile önemli ölçüde ilişkili olduğu bulundu. Bu tezde sunulan bulgular, koruma çalışmalarına rehberlik edebilir, kuş komünitelerinin stabilitesini şekillendiren faktörlere dair fikir sağlayabilir ve komüniteleri kompozisyonel ve fonksiyonel değişimlere karşı hassasiyetini tahmin etmeye yönelik gelecekteki çalışmalar için bir temel oluşturabilir.Ph.D. - Doctoral Progra
Mixing angle between P1 3 and P1 1 states in heavy axial vector mesons within the QCD sum rules framework
Get PDFIn this study, we calculate the mixing angles between the axial-vector mesons D1(s1)-D1(s1)′ and B1(s1)-B1(s1)′ using the QCD sum rules approach. Our results are θ1=28.2±0.6°, θ2=26.6±0.6°, θ3=38.6±0.1°, and θ4=38.5±0.1°. These values are in good agreement with the predictions of heavy quark effective theory, particularly for the mixing angle θ=35.3°, and are compatible with several existing results in the literature. The predicted mixing angles can be tested through the analysis of semileptonic decays such as Bc→B1ℓν, Bc→Bs10ℓν, Bs→Ds1ℓν, and Bs→Ds1′ℓν, which can be investigated at experimental facilities such as LHCb and Belle II
İdeanın Kurulması ve Yeniden Kurulması: Hegel, Marx ve Badiou'da Siyaset Arayışı
No full textThe main aim of this thesis is to try to look at the crisis and debate of radical politics after the collapse of the Soviet Union from a different perspective. This study is guided by the idea that the cause of the crisis of radical emancipatory politics is neither the changing conditions of capitalism, increasing authoritarianism, or the vanishing subject, but rather the lack of an idea to bind radical politics. Therefore, this thesis is an attempt to discuss how Hegel, Marx, and Badiou construct the relationship between ideas and politics. In discussing the relationship between ideas and radical politics, the thesis focuses on how the two are intertwined, conceptualized, and, ultimately, manifested. To do so, three key concepts, dialectic, history, and finally, the concept of the subject, are examined in detail to demonstrate how and why these three strands play a critical role in constructing ideas and politics. For this reason, this study aims to rethink this crisis of politics and the concept of idea and while trying to underline the necessity for repairing the broken link between politics and the idea.Bu tezin temel amacı, Sovyetler Birliği'nin çöküşünden sonra radikal siyasetin krizine ve tartışmalarına farklı bir perspektiften bakmaya çalışmaktır. Bu çalışma, radikal özgürleştirici siyasetin krizinin nedeninin ne kapitalizmin değişen koşulları ne artan otoriterleşme ne de kayıp özne olmadığını iddia ederken bağlanacak bir ideanın yokluğunda radikal siyasetin krizde olduğu fikrinden hareket etmektedir. Dolayısıyla bu tez, Hegel, Marx ve Badiou'nun idea ve siyaset arasındaki ilişkiyi nasıl kurduklarını tartışmaya yönelik bir girişimdir. İdea ve radikal siyaset arasındaki ilişkiyi tartışırken, bu ikisinin nasıl iç içe geçtiğine, kavramsallaştırıldığına ve nihayetinde nasıl tezahür ettiğine odaklanmaktadır. Bunu yapmak için, üç anahtar kavram, diyalektik, tarih ve son olarak özne kavramlarının idea ve siyasetin inşasında nasıl ve neden kritik bir rol oynadığı ayrıntılı olarak tartışılmaktadır. Bu nedenle bu çalışma, siyaset ve idea kavramının krizini yeniden düşünmeyi amaçlarken, siyaset ve idea arasındaki kopuk bağın onarılması gerekliliğinin altını çizmeye çalışmaktadır.Ph.D. - Doctoral ProgramTÜBİTAK 2211-
Environmental controls on the conversion of nutrients to chlorophyll in lakes
No full textAnthropogenic inputs of nitrogen and phosphorus to lakes have increased worldwide, causing phytoplankton chlorophyll concentrations to increase at many sites, with negative implications for biodiversity and human usage of lake resources. However, the conversion of nutrients to chlorophyll varies among lakes, hindering effective management actions to improve water quality. Here, using a rich global dataset, we explore how the relationship between chlorophyll-a (Chla) and nitrogen and phosphorus and inferred nutrient limitation is modified by climate, catchment, hydrology and lake characteristics. Phosphorus was the dominant control in oligotrophic/mesotrophic lakes, both nitrogen and phosphorus co-limitations were dominant in (hyper)eutrophic lakes, apart from hypereutrophic shallow lakes, where nitrogen was the main limiting factor. A generalized additive model of Chla vs nutrients identified a sigmoidal-type relationship with clear breakpoints between Chla and nutrients in all depth-dependent lake categories, except for nitrogen in shallow lakes. The model revealed that Secchi depth, as the predominant factor explaining the residuals, followed by the lake thermal region, elevation, and maximum depth. Lake shoreline slope, hydraulic retention time, mean depth, shoreline length, and watershed area were also statistically significant drivers for deep lakes. Surface area was only significant in shallow lakes, as it directly affects surface heating and surface contact with the wind, resulting in non-significant impact of thermal region in shallow lakes. These findings provide new insights into the response of global lake eutrophication and its main drivers, which could assist lake managers and policy-makers in mitigating widespread lake eutrophication
Freshwater mussels can enhance zooplankton size and their grazing potential on phytoplankton with implications for water clarity in tropical eutrophic shallow lakes
No full textFilter-feeding freshwater mussels are ecosystem engineers that significantly modify the structure of biological communities and trophic status, affecting water quality. An 8-week mesocosm-experiment, with and without the freshwater mussel Sinanodonta woodiana, tested the hypothesis that this filtering-feeding mussel alters the plankton community by reducing chlorophyll a (Chl a) of larger phytoplankton (> 2.0 μm), reducing small zooplankton such as rotifers and increasing the biomass of large zooplankton such as cladocerans and copepods. These changes would enhance the ability of zooplankton to control phytoplankton in eutrophic shallow waters. Compared with the mussel-free control, treatment with mussels led to a decrease in the Chl a of phytoplankton, particularly microphytoplankton (> 20 μm) and nanophytoplankton (> 2.0 μm), and an increase in the biomass of large zooplankton such as cladocerans and copepods, while the biomass of rotifers did not change. As a result, mussels enhanced the biomass ratio of zooplankton to phytoplankton, indicating stronger grazer control of phytoplankton. Total suspended solids were reduced, and light intensity and benthic algal Chl a increased in the mussel treatment. Our study shows that this native freshwater mussel may directly and indirectly facilitate a reduction in Chl a of phytoplankton thereby improving the water quality in tropical eutrophic shallow lakes
Geç Dönem Osmanli İmparatorluk Yapisinin İnşa Teknikleri Ve Malzemeleri Üzerine Bilginin Yeniden Tesisi: İstanbul Arkeoloji Müzesi
No full text19th century was the period of westernization of Ottoman Empire. This century
involved various social, economic, political and military changes, which also led to
advances in architectural technology such as new construction techniques, usage of
new materials, new infrastructures and so on. To understand the changes in
architectural construction technology and their implications on architectural
conservation, it is essential to investigate the historical buildings built in this period.
The Istanbul Archeology Museum (IAM) Building is one of the best examples
showing these changes because of its architectural features and construction
techniques. To this end, this thesis aims to draw a picture of the Ottoman construction
techniques in 19th century through closely examining IAM Building, its construction
and restoration and repair attempts. IAM has been maintained by the adaptation of
new technologies in different decades throughout its lifetime. The thesis summarizes
and examines the conservation history of the museum in relation to the technologies
of the period of the interventions, which the building has undergone from its
construction to the present day. It focuses on the period between 1887 and 1907 and
provides a comprehensive presentation of the building’s construction history in the
light of Republic of Türkiye Presidential State Archives, Alexandre Vallaury's
original drawings, and technical data from the restoration process. The assessment
of construction techniques was also made by considering the building’s relationship
with 1894 earthquake effecting Istanbul and its performance over time.19. yüzyıl, Osmanlı İmparatorluğu'nun Batılılaşma dönemi olarak kabul edilir. Bu yüzyıl, yeni inşaat teknikleri, yeni malzemelerin kullanımı, yeni altyapılar gibi mimari teknoloji alanında ilerlemelere yol açan çeşitli sosyal, ekonomik, siyasi ve askeri değişimleri içerir. Mimari inşaat teknolojisindeki değişiklikleri ve bunların mimari koruma üzerindeki etkilerini anlamak için bu dönemde inşa edilmiş tarihi yapıların incelenmesi gerekmektedir. İstanbul Arkeoloji Müzesi (İAM) Binası, mimari özellikleri ve inşaat teknikleri nedeniyle bu değişiklikleri en iyi şekilde gösteren örneklerden biridir. Bu doğrultuda, bu tez, İstanbul Arkeoloji Müzesi Binası’nı, inşaatını ve onarım ile restorasyon girişimlerini yakından inceleyerek, 19. yüzyıldaki Osmanlı inşaat tekniklerine dair bir çerçeve çizmeyi amaçlamaktadır. İAM, var olduğu süre boyunca farklı dönemlerde yeni teknolojilerin uyarlanmasıyla korunmuştur. Tez, müzenin koruma tarihini, binanın inşasından günümüze kadar geçirdiği müdahalelerin dönemin teknolojileriyle ilişkili olarak özetlemekte ve incelemektedir. 1887 ile 1907 yılları arasındaki döneme odaklanan çalışma, binanın inşa tarihini, Türkiye Cumhuriyeti Cumhurbaşkanlığı Devlet Arşivleri, Alexandre Vallaury’nin orijinal çizimleri ve restorasyon sürecinden elde edilen teknik veriler viii ışığında kapsamlı bir şekilde sunmaktadır. Ayrıca, inşaat tekniklerinin değerlendirilmesi, yapının İstanbul’u etkileyen 1894 depremiyle ilişkisi ve zaman içerisindeki performansı göz önünde bulundurularak yapılmıştır.Ph.D. - Doctoral Progra