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Handoff Management for Mobile Devices in Hybrid Wireless Data Networks
Inayat Riaz,Aibara Reiji,Nishimura Kouji The Korea Institute of Information and Commucation 2005 Journal of communications and networks Vol.7 No.1
Today's wireless access networks consist of several tiers that overlap each other. Provisioning of real time undisrupted communication to mobile users, anywhere and anytime through these heterogeneous overlay networks, is a challenging task. We extend the end-to-end approach for the handoff management in hybrid wireless data network by designing a fully mobile-controlled handoff for mobile devices equipped with dual mode interfaces. By handoff, we mean switching the communication between interfaces connected to different subnets. This mobile-controlled handoff scheme reduces the service disruption time during both horizontal and vertical handoffs and does not require any modification in the access networks. We exploit the IP diversity created by the dual interfaces in the overlapping area by simultaneously connecting to different subnets and networks. Power saving is achieved by activating both interfaces only during the handoff period. The performance evaluation of the handoff is carried out by a simple mathematical analysis. The analysis shows that with proper network engineering, exploiting the speed of mobile node and overlapping area between subnets can reduce service disruption and power consumption during handoff significantly. We believe that with more powerful network interfaces our proposal of dual interfaces can be realized.
Riaz Iqra,Qamar Obaid Ali,Jamil Farrukh,Hussain Murid,Inayat Abrar,Rocha-Meneses Lisandra,Akhter Parveen,Musaddiq Sara,Karim Muhammad Ramzan Abdul,박영권 한국화학공학회 2023 Korean Journal of Chemical Engineering Vol.40 No.11
The use of biodiesel is a proactive measure that can be implemented to reduce emissions of greenhouse gases and other adverse environmental impacts. However, one of the major setbacks to biodiesel production is its relatively higher cost compared to petroleum diesel. The optimistic solution to this is valorization of biomasses like waste chicken fat (WCF) and clay for deriving non-edible oil and catalyst respectively. Herein, we report the synthesis of clay derived SiO2 catalyst impregnated with SrO, Bi2O3, CuO and CaO. The developed catalysts were characterized by FTIR, XRD, and SEM. XRD studies confirmed the successful impregnation of active metallic oxide on SiO2 support. Further, these catalysts were employed for biodiesel production from WCF, and SrO/SiO2 was found to be most effective and efficient catalyst for biodiesel production from WCF. Hence, SrO/SiO2 was adapted to optimize the different transesterification reaction parameters such as methanol to oil ratio, catalyst loading, reaction temperature and time. The optimized conditions for maximum biodiesel yield 98.9% were found to be 65 °C in 1 h with 12:1 methanol to oil ratio and 1 wt% catalyst loading. The biodiesel produced was also analyzed by GC-MS. The obtained biodiesel yield shows that clay can be a potential, and cost-effective, catalyst source to produce biodiesel from WCF.