Browsing by Author "Neeraj"

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Optimal Resource Allocation for Public Safety Device to Device Communication Using PSO
(Springer Science and Business Media Deutschland GmbH, 2023) Dhruvik, N.; Pavan, R.; Neeraj; Manjappa, M.
The Device to Device (D2D) communication allows two different devices in close proximity to communicate directly among themselves without relaying through the base stations (eNodeB or eNB). The D2D communication offloads the traffic from eNB and thus, has many advantages, including higher throughput and less end-to-end delay. Though the PSC was basically invented for Public Safety Communication (PSC) and to help the first responders, its distinct advantages have attracted other commercial applications as well. The eNB treats all the D2D applications equally during resource allocation and does a uniform resource allocation where one application is engaged in commercial activities. At the same time, the other saves one’s life. Thus, in this work authors proposed a novel optimized resource allocation algorithm for D2D applications which prioritizes PSC over commercial applications. In order to achieve the objective, Particle Swarm Optimization (PSO) technique was employed in the proposed work. Furthermore, a new weighted average fitness function was designed for PSO to suit the requirements. The proposed algorithm was simulated in NS-3, and the results were taken for different iterations. It was observed that the PSO algorithm for the designed fitness function achieved the local and global optimum values in a considerable amount of time. It was apparent from the results that PSC D2D pairs produced convincing results when compared to D2D pairs with commercial applications. © 2023, The Author(s), under exclusive license to Springer Nature Switzerland AG.
Performance Analysis of Refrigerants R1234yf, R1234ze and R134a in Ejector-Based Refrigeration Cycle
(2018) Yadav, A.K.; Neeraj
Performance enhancement of refrigeration and heat pump systems by cycle modification is an emerging research topic now-a-days to reduce the electricity consumption leading to mitigate the problems related to the environmental pollution by utility power plants. Due to no moving parts, low cost, simple structure and low maintenance requirements, the use of two-phase ejector has become a promising cycle modification recently. Use of ejector as an expansion device by replacing the throttle valve in the vapor compression refrigeration cycle seems to be one of the efficient ways to reduce the throttling losses or the expansion irreversibility in the refrigeration/heat pump cycle. Ejector also reduces the compressor work by raising the suction pressure to a level higher than that in the evaporator leading to the improvement of COP. The present work aims to evaluate the performance of an ejector based vapor compression refrigeration cycle under a wide range of operating conditions. Two newly proposed refrigerants i.e., R1234yf and R1234ze, and commonly used refrigerant R134a are considered for simulation and a comparative study has been carried out. A numerical model is developed and a parametric study of important parameters such as entrainment ratio, high side pressure (condenser pressure) and evaporator temperature are analyzed for the improvement of COP of the system. Results show that the COP of the R1234ze is highest compared to R1234yf and R134a for the given evaporating and condensing temperature. 2018 World Scientific Publishing Company.
Performance Analysis of Refrigerants R1234yf, R1234ze and R134a in Ejector-Based Refrigeration Cycle
(World Scientific Publishing Co. Pte Ltd wspc@wspc.com.sg, 2018) Yadav, A.K.; Neeraj
Performance enhancement of refrigeration and heat pump systems by cycle modification is an emerging research topic now-a-days to reduce the electricity consumption leading to mitigate the problems related to the environmental pollution by utility power plants. Due to no moving parts, low cost, simple structure and low maintenance requirements, the use of two-phase ejector has become a promising cycle modification recently. Use of ejector as an expansion device by replacing the throttle valve in the vapor compression refrigeration cycle seems to be one of the efficient ways to reduce the throttling losses or the expansion irreversibility in the refrigeration/heat pump cycle. Ejector also reduces the compressor work by raising the suction pressure to a level higher than that in the evaporator leading to the improvement of COP. The present work aims to evaluate the performance of an ejector based vapor compression refrigeration cycle under a wide range of operating conditions. Two newly proposed refrigerants i.e., R1234yf and R1234ze, and commonly used refrigerant R134a are considered for simulation and a comparative study has been carried out. A numerical model is developed and a parametric study of important parameters such as entrainment ratio, high side pressure (condenser pressure) and evaporator temperature are analyzed for the improvement of COP of the system. Results show that the COP of the R1234ze is highest compared to R1234yf and R134a for the given evaporating and condensing temperature. © 2018 World Scientific Publishing Company.