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Görünür ışık iletişimi tabanlı yayıncılığın deneysel değerlendirmesi.
No full textVisible Light Communication (VLC) uses light-emitting diodes (LED)s to transmit data by turning them on and off at very high speeds, too fast for the human eye to perceive. In outdoor environments, LED-based streetlights can be utilized as VLC transmitters. Given the ubiquity of streetlights, they are particularly useful for outdoor broadcasting as required in public safety systems. In this thesis, we develop an FPGA-based VLC system with on off keying using an LED-based streetlight. The system is built upon the Eclypse Z7 FPGA platform integrated with opto-electronic transmitter and receiver front ends. We present bit error rate (BER) and signal-to-noise ratio (SNR) performance results in indoor and outdoor environments, at various transmission distances.Görünür Işıkla haberleşme (VLC) ışık yayan diyotları (LED'leri) kullanarak veri iletmek için kullanılır. LED'ler çok yüksek hızlarda açılıp kapatılarak veri iletilir, ancak insan gözü bunu algılayamaz. Açık hava ortamlarında, LED tabanlı sokak lambaları VLC vericileri olarak kullanılabilirler. Sokak lambalarının yaygınlığı göz önüne alındığında, özellikle kamu güvenliği sistemlerinde gerektiği gibi tüm alıcılara aynı anda bilgi aktarma için oldukça faydalıdırlar. Bu tezde, LED tabanlı bir sokak lambası kullanarak ac ̧-kapa anahtarlama yöntemiyle FPGA tabanlı bir VLC sistemi geliştiriyoruz. Sistem, opto-elektronik verici ve alıcı ön uçları ile entegre Eclypse Z7 FPGA platformu üzerine inşa edilmiştir. Çalışmamızda farklı iletim mesafelerinde iç mekan ve dış ̧ mekan ortamlarında bit hata oranı ve sinyal gürültü oranı başarım sonuçları sunulmuştur
Turkish cashier problem with time windows and its solution by matheuristic algorithms
No full textTurkish Cashier Problem (TCP) is a new application area of the traveling salesman problem that was introduced to the literature recently. In this problem, the cashier can use public transportation or take a taxi where the cashier must visit multiple customer locations while minimizing the total transportation cost. In this study, we introduce a more realistic version of this problem where time has been integrated. This aspect is achieved by imposing time intervals within which the cashier must visit the customers. We name this problem as the TCP with time windows (TCPwTW). We develop several matheuristic algorithms to solve the TCPwTW: a modified version of the Simplify and Conquer (SAC) algorithm that was suggested for the TCP, simulated annealing (SA), original and modified versions of the migrating birds optimization (MBO) algorithm coupled with mathematical programming. We also tried to find the exact optimum using a Solver where for complex problems, only lower bounds were found. Numerical experimentation reveals that while for problems with loose time intervals, an exact solver can be considered. Once the time intervals tighten up, the best solutions can be obtained using matheuristics involving SA and MBO.Publisher versio
Measurement of the primary lund jet plane density in proton-proton collisions at √s=13 tev
No full text¿Está la pérdida del embarazo (tan) marginalizada? Evidencia empleando viñetas clínicas
No full textBackground: Perceiving that society disregards grief after pregnancy loss (disenfranchised grief) elevates bereaved parents’ psychological burden. Objective: In this research, we aimed to compare the disenfranchisement of pregnancy loss with four other loss types considering the bereaved’s gender. Method: We collected data from Turkish participants (N = 1,280) using a 5 (loss type) x 2 (gender) between-subjects design with randomly assigned vignettes. Participants reported their expected grief and behavioural tendencies toward the bereaved. We conducted MANOVA and ANOVA analyses. Results: Results revealed that participants expected higher grief for pregnancy loss than two other disenfranchised grief types (former colleague’s death, grandfather’s diagnosis with Alzheimer’s). Expected grief for pregnancy loss was higher than or similar to the level for the best friend’s loss across examinations but lower than the level for the one-year-old child’s loss. Behaviour tendencies were alike across vignettes, and their results did not paint a coherent picture. Findings did not differ by the bereaved’s gender. Conclusion: Pregnancy loss might be less disenfranchised than bereaved parents perceive it, and parents’ perceptions could be targeted in therapeutic interventions.Antecedentes: Percibir que la sociedad marginaliza el duelo luego de la pérdida del embarazo (duelo marginalizado) incrementa la carga psicológica de los padres en duelo.
Objetivo: En esta investigación, el objetivo fue el comparar la marginalización de la pérdida del embarazo con otros cuatro tipos de pérdida considerando el género de los deudos.
Métodos: Se recolectó información de participantes turcos (N = 1.280) empleando un diseño de 5 (tipo de pérdida) x 2 (género) entre los participantes con una asignación aleatoria a viñetas clínicas. Los participantes respondieron sobre su expectativa sobre el duelo y tendencias de conducta frente a los deudos de las viñetas clínicas. Se realizaron análisis de MANOVA y ANOVA.
Resultados: Los resultados mostraron que los participantes esperaban niveles más altos de duelo para los casos de pérdidas del embarazo que para otros dos tipos de duelo marginalizado (fallecimiento de un colega del trabajo; diagnóstico de la enfermedad de Alzheimer a un abuelo). La expectativa del duelo por pérdida del embarazo fue igual o más alta que para la pérdida de un mejor amigo en todos los análisis, pero fue menor que para la pérdida de un hijo de un año. Las tendencias de conducta fueron similares en todas las viñetas clínicas, y sus resultados no fueron coherentes. No hubo diferencia en los hallazgos según género.
Conclusión: La pérdida del embarazo podría ser menos marginalizada que lo que perciben los padres en duelo, y las percepciones de los padres en duelo podrían ser un objetivo de las intervenciones terapéuticas.TÜBİTAKPublisher versio
Design of a motion table for experimental verification of pointing error in FSO systems
No full textFree space optical (FSO) communication systems use near-infrared wavelength laser transmitters for wireless transmission. With their large bandwidth, high data rate and license free spectrum, FSO systems have become popular in recent years. Various factors might affect the performance of an FSO communication system. In addition to atmospheric turbulence-induced fading, FSO links are subject to fading resulting from pointing errors. To experimentally investigate the effects of pointing error, a multi-axis capable motion platform (XYZ Table) is designed and manufactured in this study. Axes on the XYZ table are controlled via Labview through a programmable logic controller (PLC). With this platform FSO pointing error was experimentally measured and verified against theoretical models for various motion parameters
Derin transformatör tabanlı varlık fiyatı ve yön tahmini.
No full textThe field of algorithmic trading, driven by deep learning methodologies, has garnered substantial attention in recent times. Within this domain, transformers, convolutional neural networks, and patch embedding-based techniques have emerged as popular choices within the computer vision community. Here, inspired by the latest cutting edge computer vision methodologies and the existing work showing the capability of image-like conversion for time-series datasets, we apply more advanced transformer based and patch-based approaches for predicting asset prices and directional price movements. The employed transformer models include Vision Transformer (ViT), Data Efficient Image Transformers (DeiT), and Swin. We use ConvMixer for a patch embedding-based convolutional neural network architecture without a transformer. Our tested transformer-based and patch-based methodologies aim to predict asset prices and directional movements using historical price data by leveraging the inher ent image-like properties within the historical time-series dataset. Before the imple mentation of attention-based architectures, the historical time series price dataset is transformed into two-dimensional images. This transformation is facilitated through the incorporation of various common technical financial indicators, each contribut ing to the data for a fixed number of consecutive days. Consequently, a diverse set of two-dimensional images is constructed, reflecting various dimensions of the dataset. Subsequently, the original images depicting market valleys and peaks are an notated with labels such as Hold, Buy, or Sell. According to the experiments, trained attention-based models consistently outperform the baseline convolutional architec tures, particularly when applied to a subset of frequently traded Exchange-Traded Funds (ETFs). This better performance of attention-based architectures, especially ViT, is evident in terms of both accuracy and other financial evaluation metrics, particularly during extended testing and holding periods. These findings underscore the potential of transformer-based approaches to enhance predictive capabilities in asset price and directional forecasting.Derin ¨o˘grenme metodolojileri tarafından y¨onlendirilen algoritmik ticaret alanı son za manlarda b¨uy¨uk ilgi g¨orm¨u¸st¨ur. Bu alanda, d¨on¨u¸st¨ur¨uc¨uler, evri¸simli sinir a˘gları ve yama g¨omme tabanlı teknikler bilgisayarla g¨orme toplulu˘gu i¸cinde pop¨uler se¸cenekler olarak ortaya ¸cıkmı¸stır. Burada, en yeni bilgisayarla g¨orme metodolojilerinden ve zaman serisi veri k¨umeleri i¸cin g¨or¨unt¨u benzeri d¨on¨u¸s¨um yetene˘gini g¨osteren mev cut ¸calı¸smalardan esinlenerek, varlık fiyatlarını ve y¨onl¨u fiyat hareketlerini tahmin etmek i¸cin daha geli¸smi¸s d¨on¨u¸st¨ur¨uc¨u tabanlı ve yama tabanlı yakla¸sımlar uyguluy oruz. Kullanılan d¨on¨u¸st¨ur¨uc¨u modelleri arasında Vision Transformer (ViT), Data Efficient Image Transformers (DeiT) ve Swin bulunmaktadır. D¨on¨u¸st¨ur¨uc¨us¨uz yama g¨omme tabanlı bir evri¸simsel sinir a˘gı mimarisi i¸cin ConvMixer kullanıyoruz. Test edilen d¨on¨u¸st¨ur¨uc¨u tabanlı ve yama tabanlı metodolojilerimiz, ge¸cmi¸s zaman serisi veri k¨umesindeki do˘gal g¨or¨unt¨u benzeri ¨ozelliklerden yararlanarak ge¸cmi¸s fiyat veri lerini kullanarak varlık fiyatlarını ve y¨on hareketlerini tahmin etmeyi ama¸clamaktadır. Dikkat tabanlı mimarilerin uygulanmasından ¨once, tarihsel zaman serisi fiyat veri seti iki boyutlu g¨or¨unt¨ulere d¨on¨u¸st¨ur¨ul¨ur. Bu d¨on¨u¸s¨um, her biri sabit sayıda ardı¸sık g¨un i¸cin verilere katkıda bulunan ¸ce¸sitli ortak teknik finansal g¨ostergelerin dahil edilme siyle kolayla¸stırılmı¸stır. Sonu¸c olarak, veri setinin ¸ce¸sitli boyutlarını yansıtan farklı bir iki boyutlu g¨or¨unt¨u seti olu¸sturulmu¸stur. Daha sonra, piyasa vadilerini ve zirvelerini g¨osteren orijinal g¨or¨unt¨ulere Tut, Al veya Sat gibi etiketler eklenmi¸stir. Deneylere g¨ore, e˘gitilmi¸s dikkat tabanlı modeller, ¨ozellikle sık i¸slem g¨oren Borsa Yatırım Fon larının (ETF’ler) bir alt k¨umesine uygulandı˘gında, temel konvol¨usyonel mimariler den s¨urekli olarak daha iyi performans g¨ostermektedir. Dikkat tabanlı mimarilerin, ¨ozellikle de ViT’nin bu daha iyi performansı, ¨ozellikle uzun test ve bekletme s¨ureleri boyunca hem do˘gruluk hem de di˘ger finansal de˘gerlendirme ¨ol¸c¨utleri a¸cısından be lirgindir. Bu bulgular, d¨on¨u¸st¨ur¨uc¨u tabanlı yakla¸sımların varlık fiyatı ve y¨on tah mininde ¨ong¨or¨u yeteneklerini geli¸stirme potansiyelinin altını ¸cizmektedir
Software architecture recovery from multiple dependency models
No full textSoftware architecture recovery tools cluster software modules based on their inter-dependencies to suggest a gross-level decomposition with high modularity. However, there are usually multiple types of dependencies among software modules, each of which can be captured with a separate dependency model. In this paper, we evaluate the effectiveness of a software architecture recovery approach that utilizes multiple such dependency models. First, we perform clustering based on various models separately. These models reflect different types of dependencies, including call dependencies, evolutionary coupling and dependencies of modules on commonly used database tables. Then, we perform cluster aggregation on the obtained clustering results to propose a packaging structure to the designer. We present an industrial case study on a large-scale legacy system from the telecommunications domain. The highest accuracy is achieved with the aggregation of clustering results obtained based on 3 dependency models. The accuracy in terms of matching between the proposed packaging and the existing one is above 65%. The non-matching results mostly pinpoint architectural anomalies as confirmed by domain experts.TÜBİTAKPublisher versio
Immigrants living in smart cities: A systematic review of their digital technology adoption and an empirical study on the adoption of smart city applications
No full textSmart city applications (SCA) facilitate the use of public transportation networks. However, immigrants usually encounter difficulties in adopting such online tools. In this research, the aim is to identify the primary factors that enable immigrants to adopt SCAs in Turkey. Several adoption drivers are tested to check whether they influence immigrants' intention to adopt SCAs. The developed model is tested empirically by using survey data collected from 139 immigrants living in Turkey. The findings indicate that all independent variables are positively associated with the adoption of SCAs. The results may provide governmental authorities with managerial insights to establish strategies for lessening the barriers to the adoption of SCAs among the immigrant population
An integrated framework for techno-enviro-economic assessment in nanogrids
No full textThis paper presents an integrated framework designed for capacity planning of grid -connected nanogrid, a small solar and energy storage system that can provide kilowatt -level services to individual buildings. This framework comprehensively evaluates nanogrid cost-effectiveness, sustainability, and reliability, employing a multi -faceted techno-enviro-economic assessment approach. Traditional nanogrid capacity planning often prioritizes peak load requirements, which may lack optimality owing to occasional peak load occurrences. Conversely, optimizing solely for base load requirements might also fall short of effectiveness, compromising reliability and sustainability objectives. The proposed framework employs a threestep, integrated process for nanogrid (NG) capacity planning. Firstly, the Planner module identifies optimal asset sizing considering a two-day lookahead logic. Then, the Operator module serves as a digital twin for the system, conducting hourly calculations over a short-term horizon. Lastly, the Evaluator module evaluates technical, environmental, and economic metrics for each solution, assessing the effectiveness of asset -sizing decisions. A simulated case study has demonstrated the effectiveness of the proposed framework. The technical assessment revealed that a PV size of 24 kW and a storage capacity of 91 kWh led to the most reliable solution, with a probability of local sufficiency of 95 percent. Furthermore, the environmental assessment showcased a renewable fraction of 94% with a PV size of 26 kW and a storage of 85 kWh. Economically, the analysis identified that a PV size of 12 kW and a storage size of 24 kWh led to the minimum total cost. In contrast, a PV size of 26 kW and a storage size of 85 kWh yielded a total operating savings of $4,801.Publisher versio
Thermal and optical analysis of a light engine with multi color and ultraviolet light emitting diodes
No full textLight Emitting diodes have been of interest for general lighting applications over the last two decades due to energy savings, color quality and long lifetime. Moreover, due to unique features such as multi color and compactness, human centric lighting and agricultural applications started being more popular than ever. In this study, thermal and optical analysis have been performed computationally with a view to developing a multi color LED light engine. The incorporation of ultraviolet (UV) LED chips makes it unique in many ways. For the application, the primary focus of this light engine is agricultural applications, especially animal or bird lighting. Hence, a mixture of red (R). green (G), blue (B), white (W) LED chips along with UV chips are required for providing a wide range of spectrum and to prevent or control diseases in some cases. Thermal investigation shows that the chip spacing affects the junction temperature of the LED package, and 1 mm wider chip spacing can reduce the temperature by 0.65% based on numerical models. Another model consisting of hexagonal chips shows higher performance. The reduction of junction temperature for this honeycomb approach is around 1.5% for 1 mm wider spacing. The diameter of the board also affects the maximum junction temperature and results showed that a 40 mm board can reduce temperature by 0.35% compared to a 35 mm board. Apart from thermal analysis, optical investigation has also been carried out. Since the current model is a miniature LED light engine, a detector of smaller area can capture the optical properties better than a large detector. A 10 ftx10 ft plane provides better incoherent illuminance than larger detectors in this study. The value of luminance in angle space is also found to be larger for the smaller detector. From Speos simulation, 1931 CIE color coordinates have been obtained for R, G, B and RGBW LED chip combinations.Samuel Ginn College of Engineering at Auburn Universit