108 sonuçlar
Arama Sonuçları
Listeleniyor 1 - 10 / 108
Yayın Generic BER analysis of VLC channels impaired by 3D user-mobility and imperfect CSI(Institute of Electrical and Electronics Engineers Inc., 2021-07) Reddy Sekhar, K.; Miramirkhani, Farshad; Mitra, Rangeet; Turlapaty, Anish ChandVisible light communications (VLC) has emerged as a high-speed, low-cost, and green supplement for the existing radio frequency (RF) based infrastructures. However, the performance of VLC based systems is found to degrade significantly due to detrimental outages caused by non-negligible variations in the VLC channel-gain, that are jointly induced by radial user-mobility and random photodetector-orientation (together designated as 3D mobility in this letter). In addition to the 3D user-mobility mentioned above, the performance of VLC based systems is further limited by imperfect channel-state information (CSI). Such degradations in the VLC-link caused by the aforementioned factors necessitate the quantification of performance-metrics for further benchmarking/receiver-design. In this work, an analytical expression for bit-error rate (BER) is derived for a single LED indoor VLC system considering the radial user-mobility, random receiver orientation, and imperfect CSI altogether. Further, the derived BER expressions are validated using computer-simulations using typical VLC channel models from the literature. A close agreement between the analytical and the simulated BER is observed, which verifies the accuracy of the presented analysis.Yayın Tulczyjew's triplet with an Ehresmann connection I: Trivialization and reduction(World Scientific, 2023-03-30) Esen, Oğul; Kudeyt, Mahmut; Sütlü, SerkanWe study the trivialization and the reduction of Tulczyjew's triplet, in the presence of a symmetry and an Ehresmann connection associated to it. We thus establish a geometric pathway for the Legendre transformations on singular dynamical systems.Yayın Sustainability via extended warranty contracts: design for a consumer electronics retailer(MDPI, 2024-01) Aksezer, Sezgin ÇağlarWarranty is one of the most important attributes of any product, from both manufacturer and consumer points of view. Although the retailers connect manufacturers to customers by selling goods, traditionally, they have isolated themselves from warranty-related matters such as customer complaints and maintenance costs. However, recent trends in consumer behavior toward extended warranty contracts have changed this approach. While retailers have started to generate considerable revenue from the sale of these contracts, sustainability is also achieved by longer product life cycles. This study analyzed the failure behavior of different classes of cell phone products and their related costs through a chain of consumer electronics retailer operating in Türkiye. To compete on pricing and customer service, a novel policy was designed for the retailer to honor the contracts in house rather than underwriting to a third party insurer as the industry standard. The maintenance records of 328 previous failures were analyzed to plot a failure model. Failure mode and effects analysis was carried out to identify failure classes and the respective costs for extended warranty design for cell phones. The expected warranty costs for coverage of the third, fourth, and fifth years of operation were determined. The results show that the retailer may achieve the same level of profit by increasing customer satisfaction along with the sustainability of the product through repair actions.Yayın How do local actors interpret, enact and contest policy? An analysis of local government responses to meeting the needs of Syrian refugees in Turkey(Routledge, 2022-05-04) Lowndes, Vivien; Karakaya Polat, RabiaAlthough 98% of Turkey’s 3.6 million Syrian refugees live outside camps, municipalities lack formal authority to initiate policies, while receiving no government funding for refugees. Drawing on interpretive policy analysis (IPA), the article unpacks the empirical puzzle of how formally weak local governments respond to refugee needs. IPA expects policy to be constituted through diverse sets of local meanings. Case studies in three districts in Istanbul revealed distinctive local narratives, some of which consolidated the national agenda of ‘hospitality’ while others focused on equal rights and integration. Municipal narratives reflected particular local contexts, selectively mobilizing deeper governing traditions. Local interpretations were enacted in specific approaches to refugee service delivery. Working with local NGOs, municipalities accessed international funds, despite national government’s vociferous critique of EU refugee policy. Even in an increasingly authoritarian setting, refugee policy was being constituted through multiple and contingent processes of local government interpretation.Yayın Turkish sign language adaptation of the Turkish Health Literacy Scale-32(NLM (Medline), 2022-09-15) Ataseven Bulun, Mehtap; Çepni, Selden; Ermez, YusufSign language speakers are at a disadvantage in terms of health literacy due to the lack of health education materials in sign languages. Deaf and hard of hearing (DHH) individuals are excluded from health literacy research due to the lack of measurement tools in their language of excellent f luency. This study aims to provide the literature with a tool that allows the measurement of health literacy among DHH individuals. The Turkish Health Literacy Scale (THLS)-32 was translated into Turkish Sign Language (TSL). After the THLS-32 was translated into TSL in video format, it was tested for validity and reliability. The translated version of the scale was administered to participants from a DHH association in Turkey who are f luent in TSL. Subsequently, a study was conducted with 207 DHH individuals. The study group was assessed in terms of their mean index scores and evaluated to have “limited health literacy” according to the THLS-32 classification. We conclude that the THLS-32 in TSL is suitable to measure health literacy in DHH individuals and to assess the impact of the health education system.Yayın Tribo-corrosion behavior of electroplating, nitrocarburizing, and QPQ processes on barrel finishing(Walter de Gruyter GmbH, 2023-11-27) Yücel, Aysu Hande; Yılmaz, Alpay; Bakkal, Mustafa; Kuzu, Ali TanerIn this study, the effects of nitrocarburizing, QPQ, and Cr coating on the surface properties of 32CrMoV12-10 gun barrels are discussed. Hardness measurements, pin-on-disc tests, and anodic polarization tests were performed to examine the hardness values, wear resistance, friction coefficient, and corrosion resistance. The hardness of the specimen treated with QPQ was found to be the highest. Comparing the hardness profiles, it was observed that the casing depth of the nitrocarburized sample was shallower than that of the QPQ-treated sample. The pin-on-disc test revealed that the nitrocarburized sample exhibited a high coefficient of friction, while the Cr-coated sample showed the lowest coefficient of friction. Analyzing the Tafel polarization curve, it was determined that the nitrocarburized and QPQ-treated specimens demonstrated similar levels of corrosion resistance. However, it can be noted that the QPQ-treated specimen had a slightly lower corrosion rate.Yayın Psychological distress and anxiety among housewives: the mediational role of perceived stress, loneliness, and housewife burnout(Springer, 2023-06) Durak, Mithat; Durak, Emre Şenol; Karaköse, SelinHousewives are experiencing chronic stress when dealing with multiple roles (cooking, shopping, tidying the house) in their daily life. Although earlier studies have documented a significant link between role overload and stress-psychological well-being in the workplace, few studies have been conducted among housewives despite their high anxiety and burnout reports. The diathesis-stress model and transactional model of stress indicate that there may be somecontributory factors related to mental health. Within these frameworks, this research aimed to examine housewives' psychological distress and anxiety by focusing on three contributory factors namely housewife burnout, perceived stress, and loneliness. The present study was a novel contribution to the literature investigating the mediating roles of those three contributory factors between psychological distress and anxiety among housewives. Participants were 500 volunteer housewives between the ages of 20 and 70 from Turkey. In addition to Demographic Information Form, The Perceived Stress Scales (PSS-10), The General Health Questionnaire (GHQ-12), The UCLA Loneliness Scale-Version 3 (UCLA LS3), The Housewives Burnout Questionnaire (CUBAC), and The Beck Anxiety Inventory (BAI) were used. Results showed that there were four paths between psychological distress and anxiety in the model, explaining 31.19% of the total variance in anxiety in housewives. The relationship between psychological distress and anxiety was mediated by perceived distress, loneliness, and housewife burnout. Specifically, the higher psychological distress and higher anxiety relationship were associated with higher perceived distress, higher loneliness, and higher housewife burnout. The findings provide beneficial insight for clinicians to prioritize the abandonment of the cope with loneliness, perceived stress, and burnout while working with housewives having psychological distress and anxiety.Yayın Effect of scanning strategies and laser parameters on metal-composite joining(Bellwether Publishing, 2021-07-27) Kuzu, Ali Taner; Karagüzel, Umut; Erbay, Batıray; Bakkal, MustafaThis study presents an investigation on the effectiveness, automation characteristics, and mechanics of joints between different material types namely glass ?ber reinforced plastics (GFRPs) and SS304 stainless steel using an industrial Nd: YAG continuous-wave laser welder and a 2-axis custom design jig. The custom design jig includes computer-controlled (CNC) step motors, which provide high accuracy position control of the selected laser patterns. Four different patterns (Linear Curve, Hilbert Curve, Triangle Weave, and Curlique Weave) are investigated under different process parameters (laser power, lap joint length, and traveling speed) to obtain more robust joints. The strength of the joint is examined by variance analysis and found that the laser power and the pattern are the most important factors. Tensile shear tests present that the best-resulted joint carried around 4000 N before fracture. Polymer vaporization resulted in sub-millimeter sized bubbles that are widely formed inside the molten zone of the GFRP specimen. Therefore, a strong joint between GFRP and SS304 stainless steel could be obtained by a direct laser joining process at low power, with load adaptable space-filling curve patterns and without needing surface pretreatment, sophisticated clamps or high clamping forces.Yayın Secular but conservative? youth, gender, and intimacy in Turkey(Routledge, 2023-01-01) Özbay, Cenk; Erol Jamieson, Maral; Bağcı, Çiğdem; Özkaplan, NurcanThis article contributes to studies on youth in Turkey by exploring gender, sexuality, intimacy, and relationship practices among college students. Our findings show that there is change (a) towards greater gender equality; (b) about attitudes regarding family, sexuality, and romance; and (c) in understanding and experiencing gendered violence in the groups of students we examined. Progressive values appear to become more common among the participants despite the increasingly conservative tone of the political and cultural climate. However, traditional relationship patterns and norms, including the idealization of monogamous relationships, robust familial ties, and sensitivity for moral reputation, seem prevalent even though these were not associated with the ascendant politico-religious conservatism. By constituting ‘secular but conservative’ intimate selves and relations, our respondents approve the freedom and right to explore possibilities for others, and yet not immediately for themselves, as they preserve an unequivocal moral self.Yayın Landscape ecological evaluation of cultural patterns for the Istanbul urban landscape(MDPI, 2022-12) Aksu, Gül Aslı; Tağıl, Şermin; Musaoğlu, Nebiye; Seyek Canatanoğlu, Emel; Uzun, AdnanWith the widespread population growth in cities, anthropogenic influences inevitably lead to natural disturbances. The metropolitan area of Istanbul, with its rapid urbanization rate, has faced intense pressure regarding the sustainability of urban habitats. In this context, landscapes comprising patches affected by various disturbances and undergoing temporal changes must be analyzed, in order to assess city-related disturbances. In this study, the main objective was to understand how urbanization changed the function of the spatial distribution of the urban mosaic and, more specifically, its relationship with the size, shape, and connection among land-use classes. For this purpose, we took Besiktas, a district of Istanbul, as the study area. We evaluated the landscape pattern of the urban environment in two stages. First, we used medium-resolution satellite imagery to reveal the general interactions in the urbanization process. Landscape- and class-level landscape metrics were selected to quantify the landscape connectivity, and the distances between classes (green areas and artificial surfaces), patterns, and processes, using five satellite images representing a time span of 51 years (1963, 1984, 1997, 2005, and 2014). The general landscape structure was examined by looking at the temporal–spatial processes of artificial surface and green areas obtained from these medium-resolution satellite images. The trends in selected landscape-level metrics were specified and discussed through the use of a moving window analysis. We then used Pleiades high-resolution satellite imagery (2015) to analyze the landscape structure in more detail. This high-resolution base image allows us to recognize the possibility of classifying basic cultural landscape classes. The findings regarding the spatial arrangement of each class in the areas allocated to 14 cultural landscape classes were interpreted by associating them with the landscape functions. Finally, particulate matter (PM10) concentration data were collected and evaluated as an ecological indicator, in order to reveal the relationships between landscape structure and landscape function. In short, we first evaluated the whole landscape structure using medium-resolution data, followed by the classification of cultural landscapes using high-resolution satellite imagery, providing a time-effective—and, therefore, essential—auxiliary method for landscape evaluation. This two-stage evaluation method enables inferences to be made that can shed light on the landscape functions in an urban environment based on the landscape structure.
