209,422 research outputs found
IP protection of mesh NoCs using square spiral routing
No full textIntellectual property (IP) core reuse is essential for the design process of system-on-chip (SoC). Network-on-chip (NoC) has been used as an independent IP core during SoC design. However, the NoC has not been protected via IP protection and paid attention on its innovations. This paper proposes the first known approach to protect the authorship and the usage legitimacy of NoCs using specially designed routing, square spiral routing. The special routing algorithm exploits routing redundancy inherent in the mesh NoCs and transports packets along the paths, which have very low probability to be taken under commonly used routing algorithms. These unique and diverse paths are exploited in this paper to embed information of the author and identify the legal buyer of NoCs, showing high robustness and credibility. The hardware implementation of an IP-protected mesh NoC shows that the area overhead is small, which is ~0.74%, and the power overhead is ~0.52%, while the functionality and performance of the network is not affected. In this paper, the approach is presented for the mesh NoC, but the idea is equally applicable to other NoC topologies where the unique and diverse paths also inherently exist
q-Differential equations for q-classical polynomials and q-Jacobi-Stirling numbers
Get PDFWe introduce, characterise and provide a combinatorial interpretation for the so-called q-Jacobi–Stirling numbers.
This study is motivated by their key role in the (reciprocal) expansion of any power of a second order
q-differential operator having the q-classical polynomials as eigenfunctions in terms of other even order operators,
which we explicitly construct in this work. The results here obtained can be viewed as the q-version of
those given by Everitt et al. and by the first author, whilst the combinatorics of this new set of numbers is a
q-version of the Jacobi–Stirling numbers given by Gelineau and the second author
-analogues of two supercongruences of Z.-W. Sun
Get PDFsummary:We give several different -analogues of the following two congruences of \hbox {Z.-W. Sun}: where is an odd prime, is a positive integer, and is the Jacobi symbol. The proofs of them require the use of some curious -series identities, two of which are related to Franklin's involution on partitions into distinct parts. We also confirm a conjecture of the latter author and Zeng in 2012
Cladding-pumped Raman fibre laser sources
No full textIn this thesis, I investigate cladding-pumped Raman fibre lasers and amplifiers. Such devices, offering a novel way to generate Raman gain, combine the advantages of the hugely successful cladding-pumped rare-earth doped fibre lasers with those of stimulated Raman scattering. They not only inherit most advantages of conventional fibre devices, such as flexibility, high efficiency, compactness, and robustness, but also provide their own advantages and distinct properties relative to conventional fibre sources, i.e., wavelength flexibility and nearly instantaneous gain without energy storage.Cladding-pumped Raman fibre laser sources utilise double-clad Raman fibres as the gain medium. These are similar to a rare-earth doped double-clad fibre except that there is no laserion doping of the core. With double-clad fibres, the high-power output from low-cost multimode pump sources can be converted into diffraction-limited signal beams, e.g., through stimulated Raman scattering. Thus, cladding-pumped Raman fibre laser sources are a kind of brightness enhancers. In the beginning of this thesis, I theoretically analyse various factors that limit the brightness enhancement of such devices. One of the limits is unwanted 2nd-Stokes generation, which restricts the area ratio between the inner cladding and core. By designing a new DCRF with a W-type core, I successfully relax this restriction by nearly five times. Combined with other factors, i.e., core damage threshold, walk-off, numerical aperture, and background loss, a brightness enhancement of more than 3500 for the designed fibre could be achieved in such devices shown by a model with right pump sources and parameters.Secondly, I focus on the conversion efficiency of such devices. A well-designed fibre with inner-cladding-to-core area ratio around six was used as a double-clad Raman fibre, pumped by a source with nearly rectangular pulse shapes. The nearly rectangular pulses were obtained from an erbium and ytterbium co-doped master optical power oscillator through prepulse shaping. A sufficiently short piece was chosen to reduce the background loss and walk-off. The highest peak power conversion into the 1st Stokes was 75% and the energy conversion efficiency was over 60% in a pulsed cladding-pumped Raman fibre amplifier.Thirdly, I study the power scalability. Theoretically, I analyse the achievable power of such devices. The core size turns out to be a critical factor in most cases. The ultimately output power is limited to around 24 kW by thermal lensing if the core is large enough and enough pump power available. Experimentally, in collaboration with co-workers, a 100 W claddingpumped Raman fibre laser was demonstrated at 1116 nm. The output beam was nearly diffraction-limited. It shows the potential of power scalability of such devices and the ability of generating high power diffraction-limited sources at wavelengths outside the conventional range that rare-earth doped fibres offer.Since a large core size is a critical factor for power scaling, new double-clad Raman fibres with large-mode areas were introduced. They were experimentally demonstrated to work as efficiently as the previous fibre. An Nd:YAG laser was used to pump one of these fibres, and a 1 mJ Raman fibre source with good beam quality was thus demonstrated. This shows that double-clad Raman fibres offer another approach to obtaining high-brightness high-energy sources. In addition, based on a cladding-pumped Raman fibre converter, a simple and efficient method was proposed to generate supercontinuum sources
New Results on Fuzzy Integral Sliding Mode Control of Nonlinear Singularly Perturbed Systems
No full textThis paper focuses on the integral sliding mode control (SMC) issue for nonlinear singularly perturbed systems via T-S fuzzy models. A new sufficient criterion for the sliding surface design is attained by adopting convexification techniques, which also guarantees the asymptotic stability of the sliding motion. Then, a new dynamic SMC synthesis scheme is developed to ensure the finite-time reachability of the sliding surface. A simulation example is shown to illustrate the validity of the developed scheme
Cladding-pumped Raman fiber with a W-type core designed for power scaling
No full textWe design a cladding-pumped fiber Raman amplifier with a wavelength-filtering W-type core for the suppression of the 2nd-order Raman Stokes. This increases the useable inner-cladding-to-core area ratio, which benefits power scaling
The q-Log-Concavity and Unimodality of q-Kaplansky Numbers
Get PDF-Kaplansky numbers were considered by Chen and Rota. We find that
-Kaplansky numbers are connected to the symmetric differences of Gaussian
polynomials introduced by Reiner and Stanton. Based on the work of Reiner and
Stanton, we establish the unimodality of -Kaplansky numbers. We also show
that -Kaplansky numbers are the generating functions for the inversion
number and the major index of two special kinds of -sequences.
Furthermore, we show that -Kaplansky numbers are strongly -log-concave
Emissions Trading, CDM, JI, and More – The Climate Strategy of the EU
Get PDFThe objective of this paper is to assess the likely allocation effects of the current cli-mate protection strategy as it is laid out in the National Allocation Plans (NAPs) for the European Emissions Trading Scheme (ETS). The multi-regional, multi-sectoral CGE-model DART is used to simulate the effects of the current policies in the year 2012 when the Kyoto targets need to be met. Different scenarios are simulated in order to highlight the effects of the grandfathering of permits to energy-intensive installations, the use of the project-based mechanisms (CDM and JI), and the restriction imposed by the supplementarity criterion.Kyoto targets, EU, EU emissions trading scheme, National allocation plans, CDM and JI, Computable general equilibrium model, DART
Tobin's Q and Financial Policy
Get PDFRecent research in macroeconomics has emphasized the importance of linking the financial and real sectors and the need for working with optimizing models. Tobin’s Q model of investment would appear to provide a framework that can satisfy these two criteria. In contrast to the original presentation of the Q model, the formal development has not recognized that the firm actively participates in a number of financial markets; in this broader context, we show that Q is likely to be an uninformative and possibly misleading signal for investment expenditures . We then endeavor to turn this negative theoretical result to positive advantage in resolving a number of empirical problems with Q models, but the modifications dictated by the theory receive little support from the data.
Retinal blood vessel segmentation(ROP)
No full textRetinal blood vessel segmentation(Retinopathy of Prematurity). The data are free only for academic purpose. Any published work which has used the data, please cite the article below: Wang J, Ji J, Zhang M, Lin JW, Zhang G, Gong W, Cen LP, Lu Y, Huang X, Huang D, et al. Automated Explainable Multidimensional Deep Learning Platform of Retinal Images for Retinopathy of Prematurity Screening. JAMA Netw Open, 2021;4(5):e218758. doi:10.1001/jamanetworkopen
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