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Yayın Using the ultrasonic stress wave technique to evaluate structural timber members of an old masonry building(Kastamonu Univ, Orman Fak, 2018) Koca, Gülru; Dündar, Türker; As, NusretAim of study: The main objective of this study is to evaluate the current state of the structural timber members of an old masonry building by using destructive and non-destructive test methods and to determine the efficiency of non-destructive test methods by obtaining correlations between destructive and non-destructive test parameters. Area of study: Specimens were extracted from different parts of an old semi-detached masonry building in Istanbul, Turkey. The building was built at the beginning of the 20th century in Kadikoy, a residential district in the Asia side of Istanbul. Material and Methods: Ultrasonic stress wave test was carried out on specimens prepared from the structural members. Following the ultrasonic based non-destructive tests, the bending strength and modulus of elasticity in the bending tests were determined for the specimens. Main results: According to the results of the experiments, it was observed that the regression correlations were high for the softwoods (fir and spruce), but relatively lower correlations were obtained for the chestnut specimens. Highlights: Because of the good R-2 values obtained between the MOED and mechanical properties of the softwoods, the non-destructive stress wave technique can be recommended for the evaluation of softwoods in structures. Although chestnut showed very good mechanical properties, a satisfactory evaluation of the chestnut members could not be obtained because of the small number of specimens. Further investigation is needed with large sample groups.Yayın A multiplier related to symmetric stable processes(Hacettepe University, 2017) Karlı, DenizIn two recent papers [5] and [6], we generalized some classical results of Harmonic Analysis using probabilistic approach by means of a d- dimensional rotationally symmetric stable process. These results allow one to discuss some boundedness conditions with weaker hypotheses. In this paper, we study a multiplier theorem using these more general results. We consider a product process consisting of a d-dimensional symmetric stable process and a 1-dimensional Brownian motion, and use properties of jump processes to obtain bounds on jump terms and the Lp(Rd)-norm of a new operator.Yayın The impact of the COVID-19 pandemic on online grocery supply chain management: a case study in Istanbul(Gazi Üniversitesi, 2024-03) Javadi, Sonya; Keten, Olcay; Özer, Ali İhsan; Alkan, Remziye ZeynepThe COVID-19 pandemic has already crippled normal life all over the world. Its negative impact not only changed the human health system tragically but also disrupted the global economic system. One negative result was ended up in the global food supply chain. As the lockdown times have suspended the manufacturing and logistic activities, therefore, the customers have experienced unimaginable chaos in the shopping markets. Moreover, the purchasing habit of the consumers has remarkably changed compared to pre-pandemic. To meet this new demand pattern, many grocery retailers have tried to adapt to the new normal. While before COVID-19 offline grocery purchasing was popular, after the pandemic, online service got tremendous attention in market. In this study, online grocery supply chain management during the COVID-19 in Istanbul is considered. The aim is to find out how online grocery companies will serve more efficiently during the pandemics and which factors have more effect on the customer’s satisfaction. To do so, first, three popular grocery retailers in Istanbul were selected. Then, a related survey was designed to understand the consumer experience as doing online grocery shopping in COVID-19. Unsurprisingly, a result shows that 60% of the respondents did online shopping every 3-4 days in one week, and the delivery time is the most important factor for the customers. Then, the SWOT analyses were performed accordingly, and the related strategies were summarized. Finally, several managerial implications were given to may improve the company’s online services in COVID-19 and post COVID-19 in Turkey.Yayın Text-to-SQL: a methodical review of challenges and models(TÜBİTAK, 2024-05-20) Kanburoğlu, Ali Buğra; Tek, Faik BorayThis survey focuses on Text-to-SQL, automated translation of natural language queries into SQL queries. Initially, we describe the problem and its main challenges. Then, by following the PRISMA systematic review methodology, we survey the existing Text-to-SQL review papers in the literature. We apply the same method to extract proposed Text-to-SQL models and classify them with respect to used evaluation metrics and benchmarks. We highlight the accuracies achieved by various models on Text-to-SQL datasets and discuss execution-guided evaluation strategies. We present insights into model training times and implementations of different models. We also explore the availability of Text-to-SQL datasets in non-English languages. Additionally, we focus on large language model (LLM) based approaches for the Text-to-SQL task, where we examine LLM-based studies in the literature and subsequently evaluate the LLMs on the cross-domain Spider dataset. Finally, we conclude with a discussion of future directions for Text-to-SQL research, identifying potential areas of improvement and advancements in this field.
