Design of traffic shaper / scheduler for packet switches and DiffServ networks : algorithms and architectures

The convergence of communications, information, commerce and computing are creating a significant demand and opportunity for multimedia and multi-class communication services. In such environments, controlling the network behavior and guaranteeing the user\u27s quality of service is required. A flexible hierarchical sorting architecture which can function either as a traffic shaper or a scheduler according to the requirement of the traffic load is presented to meet the requirement. The core structure can be implemented as a hierarchical traffic shaper which can support a large number of connections with a wide variety of rates and burstiness without the loss of the granularity in cells\u27 conforming departure time. The hierarchical traffic shaper can implement the exact sorting scheme with a substantial reduced memory size by using two stages of timing queues, and with substantial reduction in complexity, without introducing any sorting inaccuracy. By setting a suitable threshold to the length of the departure queue and using a lookahead algorithm, the core structure can be converted to a hierarchical rateadaptive scheduler. Based on the traffic load, it can work as an exact sorting traffic shaper or a Generic Cell Rate Algorithm (GCRA) scheduler. Such a rate-adaptive scheduler can reduce the Cell Transfer Delay and the Maximum Memory Occupancy greatly while keeping the fairness in the bandwidth assignment which is the inherent characteristic of GCRA. By introducing a best-effort queue to accommodate besteffort traffic, the hierarchical sorting architecture can be changed to a near workconserving scheduler. It assigns remaining bandwidth to the best-effort traffic so that it improves the utilization, of the outlink while it guarantees the quality of service requirements of those services which require quality of service guarantees. The inherent flexibility of the hierarchical sorting architecture combined with intelligent algorithms determines its multiple functions. Its implementation not only can manage buffer and bandwidth resources effectively, but also does not require no more than off-the-shelf hardware technology. The correlation of the extra shaping delay and the rate of the connections is revealed, and an improved fair traffic shaping algorithm, Departure Event Driven plus Completing Service Time Resorting algorithm, is presented. The proposed algorithm introduces a resorting process into Departure Event Driven Traffic Shaping Algorithm to resolve the contention of multiple cells which are all eligible for transmission in the traffic shaper. By using the resorting process based on each connection\u27s rate, better fairness and flexibility in the bandwidth assignment for connections with wide range of rates can be given. A Dual Level Leaky Bucket Traffic Shaper(DLLBTS) architecture is proposed to be implemented at the edge nodes of Differentiated Services Networks in order to facilitate the quality of service management process. The proposed architecture can guarantee not only the class-based Service Level Agreement, but also the fair resource sharing among flows belonging to the same class. A simplified DLLBTS architecture is also given, which can achieve the goals of DLLBTS while maintain a very low implementation complexity so that it can be implemented with the current VLSI technology. In summary, the shaping and scheduling algorithms in the high speed packet switches and DiffServ networks are studied, and the intelligent implementation schemes are proposed for them

On the asymptotic stability and numerical analysis of solutions to nonlinear stochastic differential equations with jumps

This paper is concerned with the stability and numerical analysis of solution to highly nonlinear stochastic differential equations with jumps. By the Itô formula, stochastic inequality and semi-martingale convergence theorem, we study the asymptotic stability in the pth moment and almost sure exponential stability of solutions under the local Lipschitz condition and nonlinear growth condition. On the other hand, we also show the convergence in probability of numerical schemes under nonlinear growth condition. Finally, an example is provided to illustrate the theor

Characterization of Surface Plasmons and Toroidal Moments Using Relativistic Electrons

Plasmonics is one of the research fields in nano-optics with the emphasis on resonant light–matter interactions. Plasmonics has attracted tremendous attention by exhibiting the capability of focusing electromagnetic fields and confining the field beyond the diffraction limit, for enhancing light–matter interactions on the nanoscale. Therefore, plasmons have been applied in the fields of near-field imaging, biosensing, light harvesting, light nanofocusing and emitting, medicine thermotherapy, etc. One of the fundamental investigations is to characterize plasmonic phenomena of a single nano-object in order to systematically quantify the influence of variables in a controlled way. It requires not only the good control of nanofabrication but also an effective and comprehensive characterization tool with a spatial resolution on the nanoscale. Here, electron energy-loss spectroscopy, energy-filtered transmission electron microscopy, and cathodoluminescence spectroscopy are applied as they are the pioneering methods to ´observe´ plasmonic phenomena on the nanoscale, owing to the great instrumentation improvement in the electron energy monochromator and the stability of transmission electron microscopes. Three-dimensional gold tapers play an important role in nano-optics. They possess the capability of light nanofocusing by transforming surface plasmon polaritons on the shaft to localized surface plasmons at the apex. In this thesis, I employed electron energy-loss spectroscopy and energy-filtered transmission electron microscopy to resolve discrete plasmonic modes in this transformation region beyond the range of optical microscopy. The link and distinction of the underlying physics of the observed modes were disentangled by systematically investigating the plasmonic modes of gold tapers with different opening angles, in combination with numerical finite-difference time-domain simulations. These results suggested that there were two main coexisting mechanisms, namely reflection and phase matching, mutually contributing to the observed plasmonic modes. The dominance from reflection to phase matching was modulated when increasing the interaction length between the fast electrons and the taper near-field. Additionally, the radiation properties of the plasmonic modes in gold tapers are further investigated by using cathodoluminescence spectroscopy. The results are helpful in designing gold tapers as nanofocusing waveguides and as point sources for photon emission. Another employment of electron energy-loss spectroscopy in this thesis is to explore the fundamental electromagnetic properties of the third family of elementary electromagnetic sources, namely toroidal moments. Despite the infancy of the field, dynamic toroidal moments have recently triggered increasing research interest initiated by their peculiar symmetry character, i.e., having odd parity under time- and space-inversion symmetry operations. Metamaterial engineering makes the dominant toroidal dipole responses detectable without being masked by electric or magnetic dipoles. A toroidal dipole response can be achieved in the optical regime via plasmon-induced displacement currents. One fundamental question is, whether single dynamic toroidal dipoles radiate to the far-field. Theoretical developments have renewed the understanding of the radiative properties of toroidal dipoles, however there is still lack of experimental evidence. I have experimentally investigated the far-field radiation of toroidal dipole moments in a plasmonic heptamer nanocavity by cathodoluminescence spectroscopy. On the other hand, the present focus of this field is on the novel optical phenomena of a single toroidal dipole resonance and its interactions with electric and magnetic multipoles. Differently, I am interested in the fundamental toroidal dipole–dipole coupling, as the coupling effect tailors the optical response and can be adopted as building and manipulating element for designing potential devices. The transverse coupling of toroidal dipoles was carried out on a plasmonic decamer nanocavity. Here, I experimentally characterized the pronounced coupled toroidal modes by electron energy-loss spectroscopy and visualized them by energy-filtered transmission electron microscopy. The coupling mechanism was further illustrated via theoretical analysis, and a simplified toroidal dipole–dipole interaction model was therefore proposed in a qualitative way. The finding paves the way for further research and exploitation in the fields of nano-optics and meta-devices

Analysis on exponential stability of hybrid pantograph stochastic differential equations with highly nonlinear coefficients

This paper discusses exponential stability of solutions for highly nonlinear hybrid pantograph stochastic differential equations (PSDEs). Two criteria are proposed to guarantee exponential stability of the solution. The first criterion is a Khasminskii-type condition involving general Lyapunov functions. The second is developed on coefficients of the equation in virtue of M-matrix techniques. Based on the second criterion, robust stability of a perturbed hybrid PSDE is also investigated. The theory shows how much an exponentially stable hybrid PSDE can tolerate to remain stable

Antitumor effect of a pyrazolone-based complex [Cu(PMPP-SAL)(EtOH)] against murine melanoma B16 cell in vitro and in vivo

Pyrazolone-based derivative metal complexes were reported to have cytotoxicity in some tumor cells. In this study, the antitumor effect of [Cu(PMPP-SAL)(EtOH)] (PMPP-SAL = N-(1-phenyl-3-methyl-4-propenylidene-5-pyrazolone)-salicylidene hydrazide anion) in murine melanoma B16 cells in vitro and in vivo was investigated. The result showed that [Cu(PMPP-SAL)(EtOH)] inhibited the survival of B16 cells in vitro, and the IC50 value was superior to cisplatin (DDP) (p < 0.001). B16 cell apoptosis was significantly higher in comparison to the control group (DMSO) (p < 0.01), and cell cycle arrest occurred at the G0/G1 phase. When challenged C57 BL/6J mice were treated with [Cu(PMPP-SAL)(EtOH)], a smaller volume of B16 solid tumors were reported than the control group (p < 0.01), with lower positive expression indices of CD 34, vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) (p < 0.01). Moreover, the tumor growth was suppressed in mice due to the induction of apoptosis, as detected by the TUNEL assay (p < 0.001). In summary, [Cu(PMPP-SAL)(EtOH)] effectively inhibited the growth of B16 cells in vitro and in vivo due to the induction of apoptosis and the inhibition of intra-tumoral angiogenesis, demonstrating its therapeutic potential in melanoma treatment

Stabilisation of stochastic differential equations with Markovian switching by feedback control based on discrete-time state observation with a time delay

Feedback control based on discrete-time state observation for stochastic differential equations with Markovian switching was initialized by Mao (2013). In practice, various effects could cause some time delay in the control function. Therefore, the time delay is taken into account for the discrete-time state observation in this letter and the mean-square exponential stability of the controlled system is investigated. This letter is devoted as a continuous research to Mao (2013)

Dual radiosensitization and anti-STAT3 anti-proliferative strategy based on delivery of gold nanoparticle - oligonucleotide nanoconstructs to head and neck cancer cells

Constitutively activated signal transducer and activator of transcription 3 (STAT3) factor is an important therapeutic target in head and neck cancer (HNC). Despite early promising results, a reliable systemic delivery system for STAT3- targeted oligonucleotide (ODN) drugs is still needed for future clinical translation of anti-STAT3 therapies. We engineered and tested a novel ODN duplex/gold nanoparticle (AuNP)-based system carrying a therapeutic STAT3 decoy (STAT3d) payload. This strategy is two-pronged because of the additive STAT3 antagonism and radiosensitizing properties of AuNP. The specificity to head and neck cancer cell surface was imparted by using a nucleolin aptamer (NUAP) that was linked to AuNP for taking the advantage of an aberrant presentation of a nuclear protein nucleolin on the cell surface. STAT3d and nucleolin aptamer constructs were independently linked to AuNPs via Au-S bonds. The synthesized AuNP constructs (AuNP-NUAP-STAT3d) exhibited internalization in cells that was quantified by using radiolabeled STAT3d. AuNP-NUAP-STAT3d showed radiosensitizing effect in human HNC FaDu cell culture experiments that resulted in an increase of cell DNA damage as determined by measuring gamma-H2AX phosphorylation levels by flow cytometry. The radiosensitization study also demonstrated that AuNP-NUAP-STAT3d as well as STAT3d alone resulted in the efficient inhibition of A431 cell proliferation. While FaDu cells did not show instant proliferation inhibition after incubating with AuNP-NUAP-STAT3d, the cell DNA damage in these cells showed nearly a 50% increase in AuNP-NUAP-STAT3d group after treating with radiation. Compared with anti-EGFR humanized antibody (Cetuximab), AuNP-NUAP-STAT3d system had an overall stronger radiosensitization effect in both A431 and FaDu cells

Imaging Probes for Detecting Inflammation in the Mouse Model of Type 1 Diabetes

Non-invasive imaging of early signs of inflammation of endocrine pancreas is of importance due to a generally late clinical diagnosis of type 1 diabetes (T1D). Seventy-80% of insulin producing beta-cells could be already lost prior to the onset of clinical symptoms. Therefore, monitoring these early changes including increased vascular permeability of pancreas and activation of pro-inflammatory signaling pathways will aid in early diagnosis and timing of therapy. We have developed and tested superparamagnetic nanoparticles (NPs) with strong photoacoustic signal for detecting potential permeability changes in the pancreas of streptozotocin (STZ)- induced mouse model of T1D. These biocompatible gold/iron-oxide NPs enable application of multi-modality photoacoustic (PA) and magnetic resonance (MR) imaging to investigate the extent of NP accumulation in the pancreas. In addition, we have investigated the spatial distribution of nanoparticles in the endocrine and exocrine of pancreas using electron microscopy techniques. Our initial time-dependent histology results demonstrate the influx of macrophages and neutrophils as the first responders to pancreatic damage as well as activation of the NF-ҡB signaling pathway, which plays a central role in the inflammation of the islets. We recorded a significantly stronger PA signal in the pancreas of STZ-treated mice compared to control mice, which indicate higher accumulation of the NPs in mice with chemically induced diabetes. The potential use of a combination of clinically available imaging modality (MRI) and emerging high-resolution/high sensitivity PA makes this approach feasible for clinical translation. Furthermore, the safety of these imaging modalities makes them ideal for both initial diagnosis of diabetes in individuals at risk of T1D and for longer term noninvasive monitoring of the response to therapy