arXiv subjects

Foez Ahmed

Publications and source records attributed to Foez Ahmed.

3 recordsLinked to original sources

arXiv2026

Design of an efficient Tunable Dual narrow-band MEMS Mid and Far IR emitter with Me-NTA for Industrial and Biomedical applications

Spectrally selective infrared (IR) thermal emitters are gaining much attention now-a-days for sensing, spectroscopy and biomedical applications. In this research, two metasurface incorporated IR emitters are proposed and numerically analyzed using finite element method (FEM). First structure comprises a NiCr heater integrated with a NiCr-based metallic nanotube array (Me-NTA) metasurface to produce a single-narrowband emission in the mid-infrared (MIR) region. Furthermore, an Au-based Me-NTA metasurface on a NiCr-Au hybrid heater subsequently produces dual-narrowband emission in the short-and far-infrared (SIR and FIR) spectrums. Function of these emitters can be explained by Joule heating with the help of DC bias and consequently uniform temperature distribution can be observed along the active region. Simulation analysis shows that NiCr-metasurface based emitter produces single narrow-band near perfect emission centered at 4.5 μm in MIR region at an operating temperature of 700 K with maximum in-band conversion efficiency (CE) of 32.3% and radiated power of 199 mW. On the other hand, Au-metasurface based emitter generates dual-narrowband emission peaking at 2.5 μm and 10 μm, correlating to SIR and FIR subsequently, achieving maximum emission of 93% and 85%, respectively. The in-band CE for this emitter attains 10.4% and 4.4% in the first and second bands, associated with radiated powers of 350 mW and 147 mW, accordingly. Furthermore, execution of the emitter at 500 K reveals FIR emission with reduced power consumption. These results substantiate the possibilities of the suggested emitters in various industrial and biomedical applications.

physics.optics↗

arXiv2010

Performance Evaluation of TCP over Mobile Ad hoc Networks

With the proliferation of mobile computing devices, the demand for continuous network connectivity regardless of physical location has spurred interest in the use of mobile ad hoc networks. Since Transmission Control Protocol (TCP) is the standard network protocol for communication in the internet, any wireless network with Internet service need to be compatible with TCP. TCP is tuned to perform well in traditional wired networks, where packet losses occur mostly because of congestion. However, TCP connections in Ad-hoc mobile networks are plagued by problems such as high bit error rates, frequent route changes, multipath routing and temporary network partitions. The throughput of TCP over such connection is not satisfactory, because TCP misinterprets the packet loss or delay as congestion and invokes congestion control and avoidance algorithm. In this research, the performance of TCP in Adhoc mobile network with high Bit Error rate (BER) and mobility is studied and investigated. Simulation model is implemented and experiments are performed using the Network Simulatior 2 (NS2).

cs.NI↗

arXiv2010

Performance Evaluation of Unicast and Broadcast Mobile Ad hoc Network Routing Protocols

Efficient routing mechanism is a challenging issue for group oriented computing in Mobile Ad Hoc Networks (MANETs). The ability of MANETs to support adequate Quality of Service (QoS) for group communication is limited by the ability of the underlying ad-hoc routing protocols to provide consistent behavior despite the dynamic properties of mobile computing devices. In MANET QoS requirements can be quantified in terms of Packet Delivery Ratio (PDR), Data Latency, Packet Loss Probability, Routing Overhead, Medium Access Control (MAC) Overhead and Data Throughput etc. This paper presents an in depth study of one to many and many to many communications in MANETs and provides a comparative performance evaluation of unicast and broadcast routing protocols. Dynamic Source Routing protocol (DSR) is used as unicast protocol and BCAST is used to represent broadcast protocol. The performance differentials are analyzed using ns2 network simulator varying multicast group size (number of data senders and data receivers). Both protocols are simulated with identical traffic loads and mobility models. Simulation result shows that BCAST performs better than DSR in most cases.

cs.NI↗