Identity Negotiation of Female Esl Learners: Communities of Practice Perspective

This qualitative study employs Communities of Practice (Lave& Wenger, 1991) framework to map out how female learner identity is built and negotiated within Post-colonial Pakistan. The study traces out the ongoing identity struggles of young Pakistani female ESL learners at The Institute of English Language and Literature (IELL), University of Sindh, Jamshoro, Pakistan, from a broadly poststructuralist perspective. Data analysis and interpretation were guided by CoP framework which views learner as essentially part and parcel of the learning environment within which learning takes places. The data revealed a complex picture of Female English Language Learner Identity (FELLI), as diverse subject positions emerged while the participants developed a sense of alignment with different CoP and displaying acts of resistance to counter discrimination. Higher education appeared as a site of identity negotiation and transition into new CoP for the participants. The participants demonstrated signs of social, linguistic and academic participation in as participating members of academic CoP.

Photonic Generation of Width Tunable Uwb Pulses

Ultra-wideband (UWB) is a cutting edge, short range and huge bit rate wireless communication technique which provides communication services at Gbps data rates per user. The developing attraction for UWB is primarily due to its various interesting characteristics, such as reduced power emission, resilience to fading, little probability of interception, conformance with other wireless technologies and potential of supporting cost-efficient Gbps transmission to user ends. Owing to low power spectral density (PSD), the transmission distance is restricted from few meters to tens of meters. UWB over fiber (UWBoF) is a recent technique used to extend the range of UWB wireless transmission and also integrates the UWB services with fixed wired or wireless communication networks. Generally, this dissertation proposes various simple, efficient and novel all-optical techniques of UWB signal generation and transmission over single mode fiber (SMF), multimode fiber (MMF) and free space optics (FSO) link in order to effectively utilize the imposed Federal Communication Commission (FCC) mask. The proposed schemes are cost efficient and promising the seamless delivery of high data rate signals to user ends. In addition to UWB signal generation, a novel all-optical 2R (re-shaping and re-amplification) regeneration and continuous wave (CW) to pulsed signal wavelength conversion scheme is also presented which can be used to extend the range of UWBoF access network apart from its core function of optical signal re-shaping and reamplification. In particular, all-optical regenerative technique of width tunable UWB signal generation operating at 5 Gbps has been proposed and simulated where UWB mono-cycle pulses are generated by employing the nonlinearity of highly nonlinear fiber (HNLF) and semiconductor optical amplifier (SOA) based nonlinear mediums. Width tuning of generated UWB mono-cycle pulses is achieved with all-optical means. The regeneraix tive property of the proposed technique is verified by comparing with optical delay line (ODL) based UWB signal generation scheme. A simple and cost efficient scheme of UWB signal generation in optical domain has been proposed where UWB mono-cycle pulses are generated by exercising the nonlinearity between two linearly polarized (LP) modes in a SOA. The proposed bi-directional architecture promises the delivery of 2 Gbps data over MMF for down-link (DL) and up-link (UL) transmissions. Cost efficiency is achieved by employing direct modulation and carrier re-use techniques. This dissertation also explores the possibility of all-optical generation and transmission of UWB signals over FSO link. Therefore, a cost efficient architecture for generation and transmission of multiple UWB signals using all-optical technique over FSO link has also been presented based on Gamma-Gamma (GG) channel model which is employed between central unit (CU) and remotely distributed multiple radio access units (RAUs). The cost efficiency with added advantage of data transmission at higher data rates have been achieved by reducing the deployment cost by using FSO link instead of optical fiber and generating multiple coherent optical carriers by direct modulation of a single CW laser for data transmission. Finally, a novel all-optical 2R regenerator and CW to pulsed signal wavelength converter operating at 10 Gbps has been proposed which performs re-shaping and reamplification functions as well as wavelength conversion by inducing nonlinear chirp over CW probe by data modulated optical pulsed signal in HNLF and offset filtering. After inclusion of this 2R regenerator, the range of UWBoF access network can be extended beyond 40 km.