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Development of a tensile test procedure for unit lattice structures produced by material extrusion additive manufacturing
No full text5th International Eurasian Conference on Science, Engineering and Technology (EurasianSciEnTech 2024), June 26-28, 2024With advancing technology, additive manufacturing (AM) has revolutionized various fields, from engineering to medicine. Lattice structures additively manufactured with polylactic acid (PLA) material stand out for their innovative designs and versatile applications. Upon reviewing the literature, it is noted that a test setup needs to be developed to investigate the impact of geometric variations due to AM on the fracture behavior of unit lattice structures. The aim of this study is to develop a tensile test procedure to characterize the mechanical properties of individual lattice cells fabricated by material extrusion AM technique from PLA. Variations of the mechanical properties are also determined by a high number of samples. Given the large number of identical samples, successful and reproducible holding and alignment of the lattice cells on the tensile test machine are essential. For this purpose, various holding fixture alternatives were investigated to effectively bond the lattice cells on the fixtures by a high strength adhesive. The tensile testing process was recorded with a camera, and deformation and fracture behaviors were examined from the camera footage. When the tensile test results were analyzed in graphs, various plateaus were observed in the section identified as the elastic region. Upon examining these plateau formations in video recordings and the test system, they could be due to two factors. First, the formation of this plateau could be related to the curing time and cross-link formation of the epoxy adhesive used. Second, it could be due to the linearity between the bonding surface and the sample. Based on the results, it was shown that the developed tensile testing procedure can be used to characterize the mechanical properties of lattice cells
Assessment of Ecotropic Viral Integration Site 2b (Evi2b) Gene in Juvenile Myelomonocytic Leukemia and Neurofibromatosis Type 1 Nf1 Tumors
No full textNeurofibromatosis type 1 (NF1) is an autosomal dominant disease that affects the development and growth of various tissues. NF1 is a major risk factor for the development of malignancies, particularly malignant peripheral nerve sheath tumors, optic gliomas, and leukemia. NF1 encodes a neurofibromin. Three genes, EVI2A, EVI2B, and OMGP, are embedded within intron 27b of NF1. However, the function of these genes remains unclear. EVI2A and EVI2B encode for putative transmembrane proteins. Mouse homologs are associated with viral insertions involved in leukemia in mice. Mouse Evi2b has been identified as a direct target gene of C/EBP ; alpha;, a transcription factor critical for myeloid differentiation. Also possible is that these genes are related to the leukemia observed in patients with NF1. These genes might act as modifiers of NF1 phenotypic variations. Therefore, we investigated the EVI2B gene in leukemia and NF1 tumors. We analyzed DNA from 10, 20, and 3 patients with NF1, leukemia, and NF1-leukemia, respectively, and six NF1 tumor tissues. DNA sequencing analysis was used to identify the viral integration sequence, and the protein amounts and EVI2B gene expression were analyzed by flow cytometry and quantitative real-time PCR techniques. The EVI2B gene expression was increased in cutaneous neurofibroma compared with the control both at the level of protein and mRNA. However, its expression in plexiform neurofibroma was decreased significantly at protein level and increased at mRNA level compare to control. Moreover, integration of 455 bases near the 3 ; PRIME; end of the exon was detected. When this integrated sequence was blasted into the NCBI retroviral genome database, an 87% match with the HIV-1 virus envelope gene was obtained. These preliminary results show that EVI2B might be important in NF1 tumorigenesis and leukemia
Discrete Phase Reconfiguration of Intelligent Reflecting Surfaces Via Deep Learning
No full textIntelligent Reflective Surface (IRS), is a cost-effective technology suitable for achieving high spectrum and energy efficiency in future wireless communication systems. If the elements of an IRS are adjusted correctly, a power gain is provided that is directly proportional to the square of the number of elements. Configuring the elements of an IRS is a challenging task, and prior works have mostly assumed that the elements' phase shifts take continuous values. This paper investigates a wireless communication system in which the IRS phase shifts can only take a finite number of values. This study presents a Deep Learning approach for configuring discrete phase shifts of IRS elements. The proposed method uses the pilot signals reflected by the IRS as the model input and provides the optimum phase shift values as its output
A Comparison of the Myerson Value and the Position Value
No full textArtificial Intelligence;Autonomous Agents and Multi-Agent Systems;et al.;NSF;University of Auckland;University of Auckland, School of Computer ScienceInternational Foundation for Autonomous Agents and Multiagent Systems (IFAAMAS) -- 23rd International Conference on Autonomous Agents and Multiagent Systems, AAMAS 2024In the realm of graph-restricted games, the underlying network structure plays a pivotal role, enforcing a key constraint: communication between agents is only feasible if a valid path connecting them exists within the network. This constraint significantly influences the dynamics and strategies, particularly in value allocation scenarios among connected agents. Among various contributions to the allocation rules for such network-centric scenarios, Myerson's pioneering work stands out [4, 5]. Named after him, the Myerson value represents an adaptation of the Shapley value [7]. Another prominent concept in this domain is the position value [1, 6]. Both serve as solution concepts, offering distinct perspectives, with the Myerson value focusing on agents and the position value on links between agents. We provide an axiomatic characterization of the Myerson value based on two fundamental axioms. Expanding our investigation, a subtle modification of the first axiom leads to a characterization of the position value. This extension enables comparing these value operators, highlighting their essential distinctions and similarities. © 2024 International Foundation for Autonomous Agents and Multiagent Systems
Do Relative Concerns Matter? Testing Consumption Categories
No full textRelative concerns influence many economic choices, including household consumption decisions. In this study, we test the conspicuous consumption hypothesis. In particular, we test whether non-rich households are affected by the consumption of rich households and whether they increase their consumption of visible items to signal high status. This is one of the few studies to investigate status signaling in a developing country setting for different consumption categories. We use nationally representative data from the Turkish Household Budget Survey for the years 2003-2012. The conspicuous consumption hypothesis is validated for highly visible nondurable consumption items that possess signaling values. By contrast, we find no evidence of a similar effect on the consumption of non-visible items by the non-rich. We interpret our findings based on the economic experience of the country during the study period.Scientific and Technological Research Council of Turkey [217K057]Unay Tamgac Tezcan and Asena Caner are both in the Department of Economics at TOBB University of Economics and Technology, Ankara, Turkey. The authors are grateful to Thanasis Stengos, Naci Mocan, and participants at the University of Guelph Department of Economics Seminar, 5th International Conference on Applied Theory, Macro and Empirical Finance 2019; International Conference on Economics Turkish Economic Association 2016 ICE-TEA for their helpful comments and suggestions. The authors also express gratitude to the Scientific and Technological Research Council of Turkey for generously supporting this work through project number 217K057 and to the Turkish Statistical Institute for sharing the micro data. All remaining errors are their own
Controlling the Electro-Optical Properties of an Alsb Monolayer With a Dlhc Structure Through Phosphorus Alloying: a Dft Study
No full textThe experimental knowledge of the AlSb monolayer with a double-layer honeycomb structure is largely based on a recent publication [Le Qin et al., ACS Nano 2021, 15, 8184]. In the present work, we aim to explore the effect of phosphorus alloying on the structural, electronic, and optical properties of the AlSb monolayer (AlSbxP1-x). Phonon dispersion curves and cohesive energies, along with the Born criterion, demonstrate the stability of these structures. Our results show that with increasing P-concentration (from 0.375 to 1.0), the bandgaps increase to 1.25 eV, PBE (1.15 eV, PBE + SOC) for the alloyed AlSb structure with 0.875 P content, and an increase of 0.95 eV (PBE) and 0.56 eV (PBE + SOC) compared to that of the pristine AlSb bandgap. The largest bandgap is calculated to be 1.7 eV, PBE (1.65, PBE + SOC) for the AlP monolayer. Interestingly, for all P-concentrations, the bandgaps are direct, signifying potential applications of the material in photovoltaic applications. For P-contents from P = 0 to 0.375, the bandgap initially slightly decreases. The adsorption spectra are also found to depend on the concentration of P-dopant, where low concentration is found to be better than the high concentration for adsorption in the visible light range, while high concentration is better than low concentration for ultraviolet radiation. The variation of the bandgap with P-dopant concentration suggests the potential of these monolayer alloys for tunable bandgap engineering and application in future nano-optoelectronic devices.Iran National Science Foundation [4020997]; Iran National Science Foundation (INSF)This work was based on the research founded by Iran National Science Foundation (INSF) under project no. 4020997. Furthermore, the numerical calculations reported in this paper were fully/partially performed at TUBITAK ULAKBIM, High Performance and Grid Computing Center (TRUBA resources)
Ankara Apartmanları: Architectural Representation & Reproduction In Social Media
No full textBu çalışma, Türkiye 20. yüzyıl modern mimarlığının önemli bir unsuru olan Ankara Apartmanları kavramını, tarihsel, kültürel ve sosyal boyutlarıyla birlikte dijital temsilleri üzerinden incelemektedir. Çalışma, mimari analizleri sosyal medya içeriklerinin eleştirel bir incelemesiyle birleştirerek Ankara Apartmanları kavramını hem fiziksel hem de kavramsal bir varlık olarak tanımlamayı ve genişletmeyi amaçlamaktadır. Araştırma, Ankara Apartmanları'nın fiziksel ve dijital temsillerini incelemek amacıyla tarihsel bağlam analizini ve sosyal medya içeriklerinin derinlemesine incelenmesini birleştiren kapsamlı bir yöntemsel çerçeve benimsemektedir. Tarihsel analiz, Türkiye'nin modernleşme sürecinde Ankara'daki apartman yapılaşmasının gelişimine dair içgörüler sunarken, sosyal medya analizi bu yapıların özellikle Instagram gibi platformlarda nasıl temsil edildiğini ve yeniden yorumlandığını incelemektedir. Bulgular, Ankara Apartmanları'nın yalnızca Türkiye'nin kentsel dönüşümünün fiziksel belirteçleri olarak değil, aynı zamanda mimari ayrıntılarının vurgulandığı, paylaşıldığı ve sıklıkla yeniden bağlamlandırıldığı dijital söylemin özneleri olarak da hizmet ettiğini ortaya koyuyor. Araştırma ayrıca kullanıcı etkileşim dinamiklerini ve bu dinamiklerin mimari anlatıların şekillenmesindeki rolünü anlamak için Instagram hesaplarını tematik gruplara ayırmaktadır. Temsildeki estetik unsurlar ve tarihsel bağlam gibi belirgin temaların öne çıkarıldığı kalıplar belirlenmiştir. Bu analizler, sosyal medyanın mimari temsili demokratikleştirmedeki rolünü vurgulamakta ve Ankara'nın mimari mirasıyla yeni etkileşim biçimlerini teşvik etmektedir. Bu araştırma, Ankara Apartmanları kavramının fiziksel ve dijital temsilleri arasındaki kesişimi anlamak için kapsamlı bir çerçeve sunmaktadır. Tarihsel mimari ile dijital medya arasındaki ilişkiyi ele alarak, kentsel kültürel belleğin korunması ve yeniden yorumlanmasına yönelik tartışmalara katkıda bulunmaktadır. Bulgular, dijital platformların mimarlık söylemini ve toplumsal katılımı nasıl etkilediğine dair eleştirel bir bakış sunmaktadır. Anahtar Kelimeler: Ankara Apartmanları, Mimari Temsil, Sosyal Medya, Dijital Mimari, Kentsel Bellek, Cumhuriyet Dönemi, Apartman Yapısı, Instagram, Mimari Üretim, Dijitalleşme, Görsel AnlatılarThis study investigates the concept of Ankara Apartmanları, a significant element of Turkey's mid-20th-century modernist architecture, focusing on its historical, cultural, and social dimensions alongside its digital representations. By integrating architectural analysis with a critical examination of social media content, the study seeks to define and expand the understanding of Ankara Apartmanları as a physical and conceptual entity. The research adopts a comprehensive methodological framework, integrating historical context analysis with an in-depth examination of social media content to explore the representation and evolution of Ankara Apartmanları in both physical and digital realms. Historical analysis provides insights into the development of Ankara's apartment buildings during Turkey's modernization process. In contrast, social media analysis examines how these buildings are represented and reinterpreted on platforms, particularly Instagram. The findings reveal that Ankara Apartmanları serve not only as physical markers of Turkey's urban transformation but also as subjects of digital discourse, where their architectural details are highlighted, shared, and often recontextualized. The study further categorizes Instagram accounts into thematic groups to understand the dynamics of user interactions and their role in shaping architectural narratives. It identifies patterns in the representation of Ankara Apartmanları, including the emphasis on specific aesthetic elements and historical contexts, which contribute to their contemporary cultural significance. These analyses underscore the role of social media in democratizing architectural representation and fostering new forms of engagement with Ankara's architectural heritage. This research offers a comprehensive framework for understanding the intersection of physical and digital representations of Ankara Apartmanları. By addressing the interplay between historical architecture and digital media, the study contributes to ongoing discussions on the preservation and reinterpretation of urban cultural memory in the digital age. The findings provide a critical perspective on how digital platforms influence public perception and participation in architectural discourse. Keywords: Ankara Apartmanları, Architectural Representation, Social Media, Digital Architecture, Urban Memory, Republican Era, Apartment Building, Instagram, Architectural Production, Digitalization, Visual Narrative
Priority-Based Bin Packing With Subset Constraints
No full textThis paper is concerned with a new variant of bin packing called priority-based bin packing with subset constraints (PBBP-SC). PBBP-SC is a variant of traditional bin packing (TBP). In a TBP instance, we are given a collection of items {t1,t2,…tn}, where each item ti has size si∈(0,1). The goal of TBP is to pack the items in as few unit-sized bins as possible. In a PBBP-SC instance, we are given a collection of n unit-size items and a collection of m bins of varying capacities. Associated with each item is a positive integer which is called its priority. The priority of an item indicates its importance in being included in a (possibly infeasible) packing. As with the traditional case, these items need to be packed in the fewest number of bins. What complicates the problem is the fact that each item can be assigned to only one of a select set of bins, i.e., the bins are not interchangeable. We investigate several problems associated with PBBP-SC. The first problem we study is the feasibility problem. This is the problem of checking if there is a feasible assignment to a given PBBP-SC instance. The second problem we study is the priority maximization problem. This is the problem of finding a maximum priority assignment of an infeasible PBBP-SC instance. The third problem we study is the bin minimization problem. This is the problem of finding an assignment with the fewest number of bins to pack all of the items in a feasible PBBP-SC instance. We derive a number of results from both the algorithmic and computational complexity perspectives for these problems. In particular, we show that both the feasibility and priority maximization problems are solvable in polynomial time. We also show that the bin minimization problem is log-APX-complete and cannot be solved in time o(1.41m) unless the Strong Exponential Time Hypothesis fails. © 2023 Elsevier B.V.Defense Advanced Research Projects Agency, DARPA: HR001123S0001-FP-004This research was supported in part by the Defense Advanced Research Projects Agency through grant HR001123S0001-FP-004
Türkiye'deki Z Kuşağı Tüketicilerin Sürdürülebilir Modaya Yönelik Algıları ve Algılanan Kaliteye İlişkin Bir İnceleme
No full textBu çalışmanın amacı Türkiye'deki Z kuşağının sürdürülebilir moda hakkındaki algı ve tutumlar ile kalite değerlendirmelerini anlamaktır. Çalışmanın verileri farklı yaşlardaki Z kuşağı katılımcılarına yönelik yapılan mülakatlarla elde edilmiştir. Elde edilen veriler, nitel bir araştırma yöntemi olan Tematik Analiz yöntemiyle incelenmiştir. Çalışmadaki temel sorular, "Türkiye'deki Z kuşağı tüketiciler sürdürülebilir modaya yönelik algı ve görüşleri nedir?", "Türkiye'deki Z kuşağı tüketiciler sürdürülebilir modaya yönelik kaliteyi nasıl algılamaktadırlar?" ve "Türkiye'deki Z kuşağı tüketicilerin sürdürülebilir modaya yönelik algıladıkları riskler nelerdir?" sorularıdır. Nitel yöntemler kullanılarak yapılan bu keşfedici çalışmada Türkiye'deki Z kuşağı tüketicilerinin, çevre sorunlarına duyarlı oldukları ve sürdürülebilirlik kavramına değer verdikleri, bu nedenle sürdürülebilir modaya olumlu baktıkları ancak henüz tam olarak bu kavrama adapte olamadıkları sonucuna varılmıştır.The purpose of this study is to understand the perceptions and attitudes of Generation Z in Turkey towards sustainable fashion, as well as their quality evaluations. The data for the study was obtained through interviews conducted with Generation Z participants of various ages. The collected data was analyzed using Thematic Analysis, a qualitative research method. The main questions in the study were "What are the perceptions and opinions of Generation Z consumers in Turkey regarding sustainable fashion?", "How do Generation Z consumers in Turkey perceive quality in sustainable fashion and how do they evaluate quality?", and "What are the perceived risks of Generation Z consumers in Turkey regarding sustainable fashion?" In this exploratory study conducted using qualitative methods, it is concluded that Generation Z consumers in Turkey are environmentally conscious and value the concept of sustainability, thus they have a positive view of sustainable fashion; however, they have not fully adapted to this concept yet
Problem Space Search Metaheuristics With Fix and Optimize Approach for the Integrated Fleet Sizing and Replenishment Planning Problem
No full textThe aim of the current study is to put forward a new metaheuristic method for the problem of vehicle fleet dimensioning and shipment schedule planning. The problem includes making decisions on both the configuration of a fleet for serving customers with a single product and the replenishment schedules according to a set of given candidate delivery frequencies. The problem combines two significant logistical issues specifically fleet sizing and replenishment planning. The principal idea of the model is to minimize all the relevant costs which covers the costs related to vehicle ownership, inventory, and routing. We bring forward two versions of a Problem Space Search metaheuristic that apply fix and optimize heuristic repeatedly. The metaheuristics rely on both perturbing data and the sequence of subproblems generated in the fix and optimize algorithm. The novel metaheuristic techniques developed in the current study exhibit significant efficacy compared to existing studies on a group of non-small randomly generated instances. Results show that there is a noticeable decrease in the gaps from optimal/ best bounds taken from CPLEX and solution duration compared to previously employed solution technique