5916 research outputs found
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Minimum operation altitude for self-sustainable operation of solar-powered fixed-wing AAVs in airborne networks
No full textNon-terrestrial networks (NTNs) play a pivotal role in advancing 6G and beyond networks by providing global coverage for backbone infrastructure, wireless access, and backhauling. In particular, fixed-wing autonomous aerial vehicles (AAVs) at tropospheric altitudes are positioned as an efficient platform to provide backhauling for ground-based base stations using high-capacity point-to-point wireless links that operate at either optical or radio spectrum. These AAVs are typically solar-powered to ensure self-sustainability for extended operation durations. Higher altitudes improve energy harvesting by bringing the AAV closer to the Sun and reducing energy consumption due to lower air density. Achieving self-sustainability requires determining the minimum operational altitude at which energy harvested consistently exceeds consumption. In this paper, we derive a closed-form expression for the minimum operational altitude of solar-powered fixed-wing AAVs, ensuring a balance between harvested and consumed energy. Key factors such as geographical location, time of year, AAV mass, and solar panel efficiency are shown to significantly influence this altitude, making them critical to the system's sustainable operation.Publisher versio
How ethical is earnings management? Evidence from an emerging economy
No full textBuilding upon Role Theory, Agency Theory, and Experiential Learning Theory, this study explores the ethical viewpoints of earnings management (EM) across various professional roles within the accounting and finance profession in Turkey. Employing survey methodology and in-depth interviews, data were collected from educators, students, accountants, and auditors to provide insights into the ethics of EM, enhancing understanding and informing more ethically grounded practices within accounting and finance. This study identifies not only traditional opportunistic and informative forms of EM but also unveils strategic and deceptive dimensions, reflecting diverse ethical interpretations across professional roles. It posits that perceptions of EM's ethicality differ among stakeholder groups, influenced by professional roles and experience. Findings reveal that students have more lenient views due to limited experience, whereas auditors and accountants exhibit stricter stances, shaped by practical exposure. Educators influence these perceptions, highlighting the need for enhanced ethical guidance in education and practice
Instrumented chair for sitting posture evaluation
No full textAn instrumented chair (IC) is proposed in this study to evaluate the sitting posture in a simple manner. This chair is capable of measuring the forces and pressure distribution during sitting in critical regions, i.e., under feet, sitting, and armrest regions, which are sensorized. One of the authors of this manuscript participated in these experiments. The results show that the difference in forces at the right and left side and also the pressure distribution at the hands and feet separately during sitting and standing using this relatively low-cost and accessible system
Integrating user needs with collection mapping: A definitive case study of Özyeği̇n University Library
No full textIn this study, the collection mapping method aims to evaluate the efficiency and adequacy of Özyeğin University Library's collection. Collection mapping has revealed to what extent the collections align with academic programs and changing user profiles. In recent years, user profiles in university libraries have
undergone significant changes. This study aims to address this need while increasing the collection's visibility. Search in the LC web Classification. The
Library of Congress Classification System is used in the collection mapping process. All classification numbers from A to Z were scanned using the LC
Classification Search. Additionally, based on the faculties of Ozyeğin University, currency, and subject distribution were analysed, and strengths and areas for improvement were identified. The collection scope was limited to printed books and ebooks accessed through the ownership model. This study provides quantitative evidence on faculty course content, addressing user needs and academic expectations
Analyzing the requirements for transitioning to sustainable aviation fuels using the spherical fuzzy AHP method
No full textOver the past years, the enhancement of global movements in climate change has improved the demand of sectors for better sustainable alternatives. The aviation industry, which plays an essential role in the socioeconomic development of countries and even the world, is one of these industries. The industry primarily relies on the consumption of fossil-based jet fuels that increase the emission of greenhouse gases. Based on this fact, the aviation industry has focused on protecting the environment to reduce its environmental footprint. This effort of the industry has attracted attention. One of the most significant steps in the aviation industry is the adoption of sustainable aviation fuels (SAF) and making the continuous transition to SAF use a priority. Selection of the most appropriate SAF among the alternatives for transitioning to SAFs is a complex decision-making problem that consists of economic, technological, environmental, and social dimensions and their criteria. Therefore, this study aims to investigate, model and analyze the main factors involved in adopting SAF to reduce the environmental impact of the aviation industry. In this study, which proposes a model based on the opinions of experts and the results of the literature review, the multi-criteria decision making (MCDM) approach is adopted due to the structure of the proposed model and the nature of the problem. The suitability, validity and applicability of the proposed model are supported by an application in Turkey. Within the scope of this application, the weights used in the prioritization of the criteria related to the proposed model are calculated spherical fuzzy AHP method. The study provides a detailed analysis and valuable insights for a successful transition to SAF in the aviation industry in terms of its application area, scope and results.Özyeğin Üniversites
Thiamine (vitamin B1) levels and sensory properties of cooked rice: Exploring varietal differences
No full textThe composition and cooking quality of rice varieties vary highly. Preparation and cooking techniques may lead to thiamine degradation. In this study, rice meals were prepared with three different rice varieties grown in T & uuml;rkiye (Baldo, Osmancik, and Cammeo), four different fats (sunflower oil, margarine, butter, and olive oil), and two different cooking methods (Salma and Roasted), and thiamine amount and sensory attributes were investigated. Thiamine levels of raw rice were measured as 0.399 +/- 0.0210, 0.299 +/- 0.0010, and 0.303 +/- 0.0070 mg/100 g in Baldo, Osmancik, and Cammeo, respectively. The thiamine amount varied between 0.038 +/- 0.0020 and 0.176 +/- 0.0020 mg/100 g in rice meals, and the highest value was observed in Osmancik rice cooked with margarine using the Roasted method. Descriptive sensory analysis (DSA) assessed 8 taste attributes. Salma-cooked samples had a higher intensity of starchy and butter taste than the Roasted-cooked ones. Roasted-cooked rice meals had a higher intensity of sweet, salty, margarine, olive oil, sunflower oil, and roasted taste than the Salma-cooked samples
Fed-StackFPAD: Federated learning for face presentation attack detection with stacking to tackle data heterogeneity
No full textFace presentation attack detection (FPAD) is crucial for ensuring the accuracy and reliability of face recognition and verification systems. However, existing datasets in the literature exhibit limitations in the diversity of presentation attack types they encompass. Deep learning-based solutions that perform well on one dataset may not generalize well to others due to domain shift issues. A potential approach to improve the robustness of deep learning models involves expanding dataset diversity through multi-source data collection. However, this process is hindered by challenges such as extensive data labeling and privacy concerns of centralized data collection. To overcome these challenges, we introduce Fed-StackFPAD, a federated learning (FL) framework for FPAD that integrates a pretrained self-supervised transformer-based masked autoencoder with stacking-based ensemble learning. By leveraging model aggregation across multiple clients, the proposed framework enhances performance without requiring centralized data sharing. The meta-model in the stacking phase combines complementary strengths of the federated model and data center-specific models in the ensemble. Experimental evaluations using 4 different datasets demonstrate that Fed-StackFPAD outperforms existing state-of-the-art methods, highlighting its effectiveness in addressing domain adaptation challenges through FL, self-supervised masked image modeling using vision transformers, and stacking-based model aggregation. Fed-StackFPAD demonstrates a significant improvement, lowering the average half total error rate (HTER) by 13.7% over the current best FL methods. © 2013 IEEE.TÜBİTAKPublisher versio
Organization as the abuser: Introducing & operationalizing organizational mistreatment
No full textThe present study conceptualizes and operationalizes organizational mistreatment, employee perceptions of receiving offensive, hostile, and demeaning treatment from their organization, thereby addressing a gap in the workplace mistreatment literature. Using qualitative and quantitative research methodologies and drawing upon three independent samples, we defined the domain of organizational mistreatment, developed a measure tapping this construct, showed the construct validity of the developed measure, and examined its criterion-related and incremental validity. The results show that employees across diverse industries and organizational types can identify harmful acts in which their organization is perceived as the perpetrator. This study is the first to delineate the domain of the organizational mistreatment construct. The results indicate that the newly developed scale is internally consistent and unidimensional, distinct from abusive supervision, and has criterion-related validity with respect to important outcome variables (i.e., counterproductive work behaviors, affective organizational commitment, job satisfaction, subjective well-being, and burnout). We discuss implications of the construct and the measure together with the limitations of the study.TÜBİTAK ; Orta Doğu Teknik Üniversites
Social impact-oriented projects & design thinking: A study on social enterprises
No full textThe world is facing social problems unmet. Governments, institutions, companies, organizations and individuals are concerned about these problems by creating social impact. Social entrepreneurship and social innovation are ways in which social impact can be achieved by providing solutions to unmet social needs. Design thinking is also the method to solve problems within the framework of designers’ way of thinking. So, it can be mentioned that they are to create solutions. While social problems surround the world so much, the ways to find solutions should work together more. This study first focuses on literature to show the intervened relationship between social impact-oriented projects and design thinking while approaching problems by defining notions. In the research part of the study, the depth-interview method is used to understand social entrepreneurs’ journey while establishing their projects and creating social impact. Then these interviews are coded and findings are defined according to these codes. The interview results are tabulated according to the entrepreneurs' processes. Although design thinking gives us some stages, it is also seen that social entrepreneurs have different inputs in real life experiences. While personal stories and experiences greatly influence social enterprise journeys, the involvement of stakeholders plays a crucial role in amplifying these initiatives and driving progress. The findings show that the real-life experience may differ from the defined process depending on today's conditions and inputs. There is an opportunity to define design thinking recommendations focused on social impact, even if there are commonalities between their experiences and design thinking. So, social impact issues should be announced more and social impact creators like social entrepreneurs should be listened more to define processes to define the relations.Publisher versio