High speed all-optical packet switching router employing single and multiple PPM based routing tables

All-optical packet switched networks with flexibility and capability to deal with the bursty traffic is one solution to deal with the ever increasing demand for bandwidth. To fully utilise the potential of such networks and to ensure that high-speed packets, passed through a number of nodes, are faithfully delivered to their intended destination with minimum delay times, packet header processing and routing decision needs to be carried out in the optical domain not in the electrical domain. This is to avoid the speed bottleneck imposed by the slow response of currently available electronic devices beyond 40 Gb/s. At present, packet header recognition is carried out by sequentially correlating the incoming packet header address with every entry of a local routing table. For a small size network, with a reasonable size routing table, sequential correlation is viable both in terms of processing speed and implementation complexity. However, for a large size network with a very large size routing table of hundreds or thousands of entries, the cost, complexity and processing time does become a real issue. The latter will lead to a noticeable increase in the packet processing time at every router, which could be significantly reduced by a non- conventional signal formatting. In this thesis, an all-optical 3-input AND gate and an all-optical 1 x2 switch with high contrast ratio are proposed as an essential element in all-optical routers. New routing schemes employing pulse position modulation (PPM) packet header format as well as single and multiple PPM based routing tables (PPRTs) are proposed and investigated. The main advantage of the proposed scheme is reduced size routing table leading to a faster router processing time compared to the routers with conventional routing tables (CRTs). The correlation-time gains offered by the proposed schemes are given by theoretical calculations. For optical packets with 4-bit binary address, all-optical 1x3 routers employing single and multiple PPRTs with an entry slot of 6.25 ps offer — 100 and — 400 times faster processing times when compared to the routers employing CRT, respectively. The performance of the proposed routers employing single and multiple PPRTs are assessed in terms of optical signal-to-noise ratio (OSNR) in multi-hop routing by means of numerical simulations and theoretical analysis. It is shown that predicted and simulated OSNR decreases by —2 dB after each hop. New packet header address formats proposed offers reduced complexity of nodes by employing single or multiple PPM based routing tables. Adopting a hybrid header address format, it is shown that routers with multiple PPRTs can operate at 160 Gb/s with the output intra-channel crosstalk of -18 dB and with output packet power fluctuation of 2 dB. Finally, a WDM router employing a single PPRT, capable of processing packets at different wavelengths simultaneously, is proposed and its inter-channel crosstalk performance is investigated. At 160 Gb/s, results obtained show an inter-channel crosstalk of — -27 dB at a channel spacing of greater than 0.4 THz and a demultiplexer bandwidth of 500 GHz

Simulation of an all-optical 1 x 2 SMZ switch with a high contrast ratio

Abstract — An all-optical 1×2 high contrast ratio (CR) switch based on the symmetric Mach-Zehnder (SMZ) interferometers is presented. Simulation results show a remarkable improvement of the inter-output CR (~25 dB) between the two outputs compared with an existing SMZ switch. It is shown that the proposed switch offers high values of inter-output CR (> 32dB) over a wide range of input powers using appropriate power of the control pulses. I

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

Metabolic Pathways Enhancement Confers Poor Prognosis in p53 Exon Mutant Hepatocellular Carcinoma.

RNA-Sequencing (RNA-Seq), the most commonly used sequencing application tool, is not only a method for measuring gene expression but also an excellent media to detect important structural variants such as single nucleotide variants (SNVs), insertion/deletion (Indels), or fusion transcripts. The Cancer Genome Atlas (TCGA) contains genomic data from a variety of cancer types and also provides the raw data generated by TCGA consortium. p53 is among the top 10 somatic mutations associated with hepatocellular carcinoma (HCC). The aim of the present study was to analyze concordant different gene profiles and the priori defined set of genes based on p53 mutation status in HCC using RNA-Seq data. In the study, expression profile of 11 799 genes on 42 paired tumor and adjacent normal tissues was collected, processed, and further stratified by the mutated versus normal p53 expression. Furthermore, we used a knowledge-based approach Gene Set Enrichment Analysis (GSEA) to compare between normal and p53 mutation gene expression profiles. The statistical significance (nominal P value) of the enrichment score (ES) genes was calculated. The ranked gene list that reflects differential expression between p53 wild-type and mutant genotypes was then mapped to metabolic process by KEGG, an encyclopedia of genes and genomes to assign functional meanings. These approaches enable us to identify pathways and potential target gene/pathways that are highly expressed in p53 mutated HCC. Our analysis revealed 2 genes, the hexokinase 2 (HK2) and Enolase 1 (ENO1), were conspicuous of red pixel in the heatmap. To further explore the role of these genes in HCC, the overall survival plots by Kaplan-Meier method were performed for HK2 and ENO1 that revealed high HK2 and ENO1 expression in patients with HCC have poor prognosis. These results suggested that these glycolysis genes are associated with mutated-p53 in HCC that may contribute to poor prognosis. In this proof-of-concept study, we proposed an approach for identifying novel potential therapeutic targets in human HCC with mutated p53. These approaches can take advantage of the massive next-generation sequencing (NGS) data generated worldwide and make more out of it by exploring new potential therapeutic targets

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

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

High speed all-optical packet switching router employing single and multiple PPM based routing tables

All-optical packet switched networks with flexibility and capability to deal with the bursty traffic is one solution to deal with the ever increasing demand for bandwidth. To fully utilise the potential of such networks and to ensure that high-speed packets, passed through a number of nodes, are faithfully delivered to their intended destination with minimum delay times, packet header processing and routing decision needs to be carried out in the optical domain not in the electrical domain. This is to avoid the speed bottleneck imposed by the slow response of currently available electronic devices beyond 40 Gb/s. At present, packet header recognition is carried out by sequentially correlating the incoming packet header address with every entry of a local routing table. For a small size network, with a reasonable size routing table, sequential correlation is viable both in terms of processing speed and implementation complexity. However, for a large size network with a very large size routing table of hundreds or thousands of entries, the cost, complexity and processing time does become a real issue. The latter will lead to a noticeable increase in the packet processing time at every router, which could be significantly reduced by a non- conventional signal formatting. In this thesis, an all-optical 3-input AND gate and an all-optical 1 x2 switch with high contrast ratio are proposed as an essential element in all-optical routers. New routing schemes employing pulse position modulation (PPM) packet header format as well as single and multiple PPM based routing tables (PPRTs) are proposed and investigated. The main advantage of the proposed scheme is reduced size routing table leading to a faster router processing time compared to the routers with conventional routing tables (CRTs). The correlation-time gains offered by the proposed schemes are given by theoretical calculations. For optical packets with 4-bit binary address, all-optical 1x3 routers employing single and multiple PPRTs with an entry slot of 6.25 ps offer — 100 and — 400 times faster processing times when compared to the routers employing CRT, respectively. The performance of the proposed routers employing single and multiple PPRTs are assessed in terms of optical signal-to-noise ratio (OSNR) in multi-hop routing by means of numerical simulations and theoretical analysis. It is shown that predicted and simulated OSNR decreases by —2 dB after each hop. New packet header address formats proposed offers reduced complexity of nodes by employing single or multiple PPM based routing tables. Adopting a hybrid header address format, it is shown that routers with multiple PPRTs can operate at 160 Gb/s with the output intra-channel crosstalk of -18 dB and with output packet power fluctuation of 2 dB. Finally, a WDM router employing a single PPRT, capable of processing packets at different wavelengths simultaneously, is proposed and its inter-channel crosstalk performance is investigated. At 160 Gb/s, results obtained show an inter-channel crosstalk of — -27 dB at a channel spacing of greater than 0.4 THz and a demultiplexer bandwidth of 500 GHz.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Study of sponge gourd ascorbate peroxidase and winter squash superoxide dismutase under respective flooding and chilling stresses

AbstractThe objectives of this work were to study the responses of ascorbate peroxidase (APX), catalase (CAT), superoxide dismutase (SOD), glutathione reductase (GR), and physiological parameters of bitter melon (BM), sponge gourd (SG), and winter squash (WS) under waterlogged and low temperature conditions. The BM and SG plants were subjected to 0–72h flooding treatments. Moreover, BM and WS plants were exposed to chilling at 12/7°C (day/night) for 0–72h. The results show that different genotypes responded differently to environmental stress according to their various antioxidant enzymes and physiological parameters. The activity of APX in roots and leaves of SG plants significantly higher than that of BM plants during continuous flooding. Significant increases in SOD activity in leaves of WS plants were also observed throughout the entire chilling duration compared to BM plants. On the basis of our observations, we conclude that increased APX and SOD activities provide SG and WS plants with increased waterlogging and chilling stress tolerance, respectively. Both APX and SOD activities can be used for selecting BM lines with the best tolerances to water logging and chilling stresses

Efficacy of Intravenous Immunoglobulin/Exchange Transfusion Therapy on Gestational Alloimmune Liver Disease

Background: Gestational alloimmune liver disease (GALD) is a rare but critical cause of neonatal liver failure. After discovering the maternal–fetal alloimmune mechanism, intravenous immunoglobulin (IVIG) with or without exchange transfusion (ET) has gradually replaced antioxidant cocktails as the first-line therapy. Whether such therapy changes the outcome of neonates with GALD is yet to be defined.Method: We reported a pair of twins with discordant presentations, mild and self-limited in the older, whereas liver failure in the younger, who was successfully rescued by ET and IVIG. To investigate the outcome after therapeutic alteration, 39 cases between 2005 and 2020 from literature research were collected.Results: Half of the collected cases (47.1%) were preterm. Common presentations were ascites, jaundice, respiratory distress, hepatomegaly, and edema. Leading laboratory abnormalities were coagulopathy, hypoalbuminemia, and elevated serum ferritin. Salivary gland biopsy and magnetic resonance imaging detected extrahepatic siderosis in 70% (14/20) and 56% (14/25), respectively. IVIG, ET, and liver transplantation were performed in 19 (48.7%), 15 (38.5%), and 8 (20.5%) patients, respectively. The overall survival (OS) rate and native liver survival (NLS) rate were 64.1% (25/39) and 43.6% (17/39), respectively. Although the compiled results did not support a significant benefit, the OS and NLS were higher in the IVIG with/without ET group compared with those treated with conventional therapy [OS (70 vs. 57.9%) and NLS (55 vs. 31.6%), respectively].Conclusion: A high index of suspicion for GALD is crucial when facing a neonate with liver failure. Despite no significant influence on the outcome over conventional therapy in such a rare and detrimental disease, IVIG with or without ET can be worth trying before resorting to liver transplantation, which is resource-demanding and technique-challenging in small infants