Optimisation of the key SOA parameters for amplification and switching

Wireless Sensor Networks (WSN) are composed of small, low cost, resource-constrained computing nodes equipped with low power wireless transceivers. Generally, they are embedded in their environment to perform some specific monitoring and/or control function. Unlike wired networks that have dedicated routers for network connectivity and message forwarding, every node in a WSN can act as a router in a multi-hop network. A WSN can offer a cheap, applicationspecific solution in a variety of situations including military and disaster response scenarios, where other approaches are not viable. Due to their unattended nature and deployment in possibly hostile environmental conditions, there are many challenges in ensuring that a WSN is formed effectively and survives long enough to fulfil its function. Securing a WSN against attack is a particular challenge. Traditional encryption mechanisms are resource hungry and are not sufficient alone to provide a complete solution. This project is concerned with secure routing protocols. Formal methods are used to model and analyse the design of existing protocols and to demonstrate some previously unreported weaknesses

1 x M packet-switched router based on the PPM header address for all-optical WDM networks

This paper presents an all-optical 1xM router architecture for simultaneous multiple-wavelength packet routing, without the need for wavelength conversion. The packet header address is based on the pulse position modulation (PPM) format, which allows the use of only a single-bitwise optical AND gate for fast packet header address correlation. The proposed scheme offers both multicast and broadcast capabilities. We’ve demonstrated a high speed packet routing at 160 Gb/s in simulation, with a low channel crosstalk (CXT) of ~ -27 dB with a channel spacing of > 0.4 THz and a demultiplexer bandwidth of 500 GHz. The output transfer function of the PPM header processing (PPM-HP) module is also investigated in this paper

Metric Building of pp Wave Orbifold Geometries

We study strings on orbifolds of $AdS_{5}\times S^5$ by SU(2) discrete groups in the Penrose limit. We derive the degenerate metrics of pp wave of $AdS_{5}\times S^5/\Gamma$ using ordinary $ADE$ and affine \wildtilde{ADE} singularities of complex surfaces and results on ${\cal N}=4$ CFT$_4$'s. We also give explicit metric moduli depencies for abelian and non abelian orbifolds.Comment: 13 pages, no figure

Impact of signal wavelength on the semiconductor opticalamplifier gain uniformity for high speed optical routers employing the segmentation model

This paper investigates the impact of a train of input Gaussian pulses wavelength on semiconductor optical amplifier (SOA) gain uniformity for high speed applications. In high speed applications, the linear output gain of the input pulses is necessary in order to minimize the gain standard deviation and power penalties. A segmentation model of the SOA is demonstrated to utilize the complete rate equations. The SOA gain profile when injected with a burst of input signal is presented. A direct temporal analysis of the effect of the burst wavelength on the SOA gain and the output gain standard deviation is investigated. The output gain uniformity dependence on the input burst power and wavelength within the C-band spectrum range is analyzed. Results obtained show the proportionality of the peak-gain conditions for the SOA on the nonlinearity of the output gain achieved by the input pulses

A case report of Parry Romberg Syndrome initially presenting as periodontitis

Parry Romberg Syndrome (PRS) is a rare disorder of progressive hemifacial atrophy, involving soft tissues, fat and occasionally bone. It can co-exist with presentations of Morphea. We describe an unusual case of persistent periodontal and alveolar destruction associated with PRS. A 56-year-old African female initially presented with persistent periodontal destruction, which showed minimal response to conventional periodontal treatment. After non-surgical treatment, surgical debridement followed by extraction of the two right maxillary incisor teeth was required to halt the periodontal destruction. Atrophy was not limited to the periodontal tissues. Multidisciplinary care and extensive investigations were required to diagnose PRS. Once the PRS has stabilised, adipose tissue transplants will be required to improve the facial appearance. We highlight the need for extensive investigations and a multidisciplinary approach to diagnose rare systemic causes for recalcitrant periodontal disease

Failure of Standard Thermodynamics in Planck Scale Black Hole System

The final stage of the black hole evaporation is a matter of debates in the existing literature. In this paper, we consider this problem within two alternative approaches: noncommutative geometry(NCG) and the generalized uncertainty principle(GUP). We compare the results of two scenarios to find a relation between parameters of these approaches. Our results show some extraordinary thermodynamical behavior for Planck size black hole evaporation. These extraordinary behavior may reflect the need for a fractal nonextensive thermodynamics for Planck size black hole evaporation process.Comment: 26 Pages, 10 Figures, Revised and References adde

Implications of Minimal Length Scale on the Statistical Mechanics of Ideal Gas

Several alternative approaches to quantum gravity problem suggest the modification of the {\it fundamental volume $\omega_{0}$} of the accessible phase space for representative points. This modified fundamental volume has a novel momentum dependence. In this paper, we study the effects of this modification on the thermodynamics of an ideal gas within the microcanonical ensemble and using the generalized uncertainty principle(GUP). Although the induced modifications are important only in quantum gravity era, possible experimental manifestation of these effects may provides strong support for underlying quantum gravity proposal.Comment: 14 Pages, No Figures, Title Changed, Revised Versio

Entanglement for a Bimodal Cavity Field Interacting with a Two-Level Atom

Negativity has been adopted to investigate the entanglement in a system composed of a two-level atom and a two-mode cavity field. Effects of Kerr-like medium and the number of photon inside the cavity on the entanglement are studied. Our results show that atomic initial state must be superposed, so that the two cavity field modes can be entangled. Moreover, we also conclude that the number of photon in the two cavity mode should be equal. The interaction between modes, namely, the Kerr effect, has a significant negative contribution. Note that the atom frequency and the cavity frequency have an indistinguishable effect, so a corresponding approximation has been made in this article. These results may be useful for quantum information in optics systems.Comment: Accepted by Commun. Theor. Phy

Exploring Improvisational Approaches to Social Knowledge Acquisition

To build agents that can engage user in more open-ended social contexts, more and more attention has been focused on data-driven approaches to reduce the requirement of extensive, hand-authored behavioral content creation. However, one fundamental challenge of data-driven approaches, is acquiring human social interaction data with sufficient variety to capture more open-ended social interactions, as well as their coherency. Previous work has attempted to extract such social knowledge using crowdsourced narratives. This paper proposes an approach to acquire the knowledge of social interaction by integrating an improvisational theatre training technique into a crowdsourcing task aimed at collecting social narratives. The approach emphasizes theory of mind concepts, through an iterative prompting process about the mental states of characters in the narrative and paired writing, in order to encourage the authoring of diverse social interactions. To assess the effectiveness of integrating prompting and two-worker improvisation to the knowledge acquisition process, we systematically compare alternative ways to design the crowdsourcing task, including a) single worker vs. two workers authoring interaction between different characters in a given social context, and b) with or without prompts. Findings from 175 participants across two different social contexts show that the prompts and two-workers collaboration could significantly improve the diversity and the objective coherency of the narratives. The results presented in this paper can provide a rich set of diverse and coherent action sequences to inform the design of socially intelligent agents