Scopus İndeksli Yayınlar Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12573/395
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Article Effects of Strain Rate and Post Processing on Mechanical Properties of Additively Manufactured AlSi10Mg Alloys(Walter de Gruyter GmbH, 2026-01-12) Karaveli, K.K.; Bal, B.The mechanical properties of AlSi10Mg alloy fabricated by laser powder bed fusion (LPBF) were investigated under different strain rates and post-processing conditions, including shot peening (SP) and stress relief (SR). Tensile tests were performed at quasistatic (0.1 s−1) and dynamic (0.015 s−1) strain rates on as-built and post-processed specimens. The results revealed that SP significantly increased the yield strength by 7.10 %, reaching 249.59 MPa, due to the induced compressive residual stresses. However, while SP slightly improved the ultimate tensile strength (UTS) by 0.25 %, it also reduced elongation at break by 18.06 %, indicating a trade-off between strength and ductility. Conversely, SR improved ductility by reducing internal stresses, leading to an elongation at break increase of 574.01 %, with a slight reduction in yield strength. The combination of SP and SR exhibited a synergistic effect, achieving a balance between strength and ductility. Strain rate sensitivity (SRS) analysis indicated that stress-relieved specimens performed better under dynamic loading conditions. These findings highlight the potential of post-processing techniques in tailoring the mechanical behavior of LPBF-produced AlSi10Mg alloys. The balanced properties achieved through combined treatments make this material particularly suitable for high-performance aerospace and automotive applications, where strength and ductility are critical under varying operational conditions. © 2025 Walter de Gruyter GmbH, Berlin/Boston.Article Citation - Scopus: 3Attack-Aware Dynamic Upstream Bandwidth Assignment Scheme for Passive Optical Network(Walter de Gruyter GmbH, 2019-09-19) Butt, Rizwan Aslam; Faheem, Muhammed Yasir; Ashraf, Muhammad Waqar; Khawaja, Attaullah; Raza, BasitNetwork security is an important component of today's networks to combat the security attacks. The passive optical network (PON) works at the medium access layer (MAC). A distributed denial of service (DDOS) attack may be launched from the network and transport layers of an Optical Network unit (ONU). Although there are various security techniques to mitigate its impact, however, these techniques cannot mitigate the impact on the MAC Layer of the PON and can cause an ONU to continuously drain too much bandwidth. This will result in reduced bandwidth availability to other ONUs and, thus, causing an increase in US delays and delay variance. In this work we argue that the impact of a DDOS attack can be mitigated by improving the Dynamic bandwidth assignment (DBA) scheme which is used in PON to manage the US bandwidth at the optical line terminal (OLT). The present DBA schemes do not have the capability to combat a security attack. Thus, this study, uses a machine learning approach to learn the ONU traffic demand patterns and presents a security aware DBA (SA-DBA) scheme that detects a rogue (attacker) ONU from its traffic demand pattern and limits its illegitimate bandwidth demand and only allows it the bandwidth assignment to it as per the agreed service level agreement (SLA). The simulation results show that the SA-DBA scheme results in up to 53%, 55% and 90% reduced US delays and up to 84%, 76% and 95% reduced US delay variance of T2, T3 and T4 traffic classes compared to existing insecure DBA schemes. © 2023 Elsevier B.V., All rights reserved.Article Citation - Scopus: 4A QoS Provisioning Architecture of Fiber Wireless Network Based on XGPON and IEEE 802.11ac(Walter de Gruyter GmbH, 2021-01-12) Mohammadani, Khalid Hussain; Butt, Rizwan Aslam; Ali, Kamran Ali; Pirzado, Azhar Ali Ayaz; Faheem, Muhammed Yasir; Abro, Adeel; Ain, Noor Ul; Memon, Kamran A.The integration of the XGPON network with the 5G WLAN network is a suitable solution for next-generation high-speed access Internet service. We demonstrated the integration of two different standards via the QoS concept. Further, this work also presents a proper mapping scheme of QoS traffic between XG-PON and fifth-generation Wi-Fi standards known as IEEE 802.11ac. The analysis assessment compares the behavior of different IEEE 802.11ac standards with XGPON with-respect-to multimedia traffic in the FiWi network. To assess the performance of the FiWi network, the OMNET++ and INET framework are used to carrying out a comparative analysis in terms of upstream (US) delay and fairness index. The study concludes that the EDCA Wi-Fi module has better performance than the DCF Wi-Fi module with the integrated XGPON system for the FiWi access network. © 2024 Elsevier B.V., All rights reserved.