Homogeneous weights and exponential sums

In this paper, we give a formula as an exponential sum for a homogeneous weight defined by Constantinescu and Heise [3] in the case of Galois rings (or equivalently, rings of Witt vectors) and use this formula to estimate the weight of codes obtained from algebraic geometric codes over rings

Homogeneous weights and exponential sums

In this paper, we give a formula as an exponential sum for a homogeneous weight defined by Constantinescu and Heise [3] in the case of Galois rings (or equivalently, rings of Witt vectors) and use this formula to estimate the weight of codes obtained from algebraic geometric codes over rings

Euclidean weights of codes from elliptic curves over rings

We construct certain error-correcting codes over finite rings and estimate their parameters. For this purpose, we need to develop some tools, notably an estimate for certain exponential sums and some results on canonical lifts of elliptic curves. These results may be of independent interest. A code is a subset of An, where A is a finite set (called the alphabet). Usually A is just the field of two elements and, in this case, one speaks of binary codes. Such codes are used in applications where one transmits information through noisy channels. By building redundancy into the code, transmitted messages can be recovered at the receiving end. A code has parameters that measure its eficiency and error-correcting capability. For various reasons one often restricts attention to linear codes, which are linear subspaces of An when A is a field. However, there are non-linear binary codes (such as the Nordstrom-Robinson, Kerdock, and Preparata codes) that outperform linear codes for certain parameters. These codes have remained somewhat mysterious until recently when Hammons, et al. ([6]) discovered that one can obtain these codes from linear codes over rings (i.e. submodules of An, A a ring) via the Gray mapping, which we recall below. In a difierent vein, over the last decade there has been a lot of interest in linear codes coming from algebraic curves over finite fields. The construction of such codes was first proposed by Goppa in [5]; see [15] or [16] for instance. In [17], it is proven that for q ≥ 49 a square, there exist sequences of codes over the finite field with q elements which give asymptotically the best known linear codes over these fields. The second author has extended Goppa\u27s construction to curves over local Artinian rings and shown, for instance, that the Nordstrom-Robinson code can be obtained from her construction followed by the Gray mapping; see [20] and [21]. While most of the parameters for these new codes were estimated in the above papers, the crucial parameter needed to describe the error-correcting capability of the images of these codes under the Gray mapping was still lacking. In this paper we consider the second author\u27s construction in the special case of elliptic curves which are defined over finite local rings and which are the canonical lifts of their reductions. (See section 4 for more about canonical lifts.) For these codes, the missing parameter can be estimated, and we do so

Codes Over Rings from Curves of Higher Genus

We construct certain error-correcting codes over finite rings and estimate their parameters. These codes are constructed using plane curves and the estimates for their parameters rely on constructing “lifts” of these curves and then estimating the size of certain exponential sums. THE purpose of this paper is to construct certain error-correcting codes over finite rings and estimate their parameters. For this purpose, we need to develop some tools; notably, an estimate for the dimension of trace codes over rings (generalizing work of van der Vlugt over fields and some results on lifts of affin curves from field of characteristic p to Witt vectors of length two. This work partly generalizes our previous work on elliptic curves, although there are some differences which we will point out below

Selecting Surrogate-Based Modeling Techniques for Power Integrity Analysis

In recent years, extensive usage of simulated power integrity (PI) models to predict the behavior of power delivery networks (PDN) on a chip has become more relevant. Predicting adequate performance against power consumption can yield to either cheap or costly design solutions. Since PI simulations including high-frequency effects are becoming more and more computationally complex and expensive, it is critical to develop reliable and fast models to understand system’s behavior to accelerate decision making during design stages. Hence, metamodeling techniques can help to overcome this challenge. In this work, a comparative study between different surrogate modeling techniques as applied to PI analysis is described. We model and analyze a PDN that includes two different power domains and a combination of remote sense resistors for communication and storage CPU applications. We aim at developing reliable and fast coarse models to make trade off decisions while complying with voltage levels and power consumption requirements

Surrogate-based Analysis and Design Optimization of Power Delivery Networks

As microprocessor architectures continue to increase computing performance under low-energy consumption, the combination of signal integrity, electromagnetic interference, and power delivery is becoming crucial in the computer industry. In this context, power delivery engineers make use of complex and computationally expensive models that impose time-consuming industrial practices to reach an adequate power delivery design. In this paper, we propose a general surrogate-based methodology for fast and reliable analysis and design optimization of power delivery networks (PDN). We first formulate a generic surrogate model methodology exploiting passive lumped models optimized by parameter extraction to fit PDN impedance profiles. This PDN modeling formulation is illustrated with industrial laboratory measurements of a 4th generation server CPU motherboard. We next propose a black box PDN surrogate modeling methodology for efficient and reliable power delivery design optimization. To build our black box PDN surrogate, we compare four metamodeling techniques: support vector machines, polynomial surrogate modeling, generalized regression neural networks, and Kriging. The resultant best metamodel is then used to enable fast and accurate optimization of the PDN performance. Two examples validate our surrogate-based optimization approach: a voltage regulator with dual power rail remote sensing intended for communications and storage applications, by finding optimal sensing resistors and loading conditions; and a multiphase voltage regulator from a 6th generation Intel® server motherboard, by finding optimal compensation settings to reduce the number of bulk capacitors without losing CPU performance.ITESO, A.C

Detection of Anti-Counterfeiting Markers through Permittivity Maps Using a Micrometer Scale near Field Scanning Microwave Microscope

[EN] This paper describes the use of microwave technology to identify anti-counterfeiting markers on banknotes. The proposed method is based on a robust near-field scanning microwave microscope specially developed to measure permittivity maps of heterogeneous paper specimens at the micrometer scale. The equipment has a built-in vector network analyzer to measure the reflection response of a near-field coaxial probe, which makes it a standalone and portable device. A new approach employing the information of a displacement laser and the cavity perturbation technique was used to determine the relationship between the dielectric properties of the specimens and the resonance response of the probe, avoiding the use of distance-following techniques. The accuracy of the dielectric measurements was evaluated through a comparative study with other well-established cavity methods, revealing uncertainties lower than 5%, very similar to the accuracy reported by other more sophisticated setups. The device was employed to determine the dielectric map of a watermark on a 20 EUR banknote. In addition, the penetration capabilities of microwave energy allowed for the detection of the watermark when concealed behind dielectric or metallic layers. This work demonstrates the benefits of this microwave technique as a novel method for identifying anti-counterfeiting features, which opens new perspectives with which to develop optically opaque markers only traceable through this microwave technique.This paper has been financially supported through the grant reference BES-2016-077296 of the call Convocatoria de las ayudas para contratos predoctorales para la formacion de doctores de 2016 by Ministerio de Economia y Competitividad (MINECO) and by European Social Funds (ESF) of European Union, and the project SEDMICRON-TEC2015-70272-R (MINECO/FEDER) supported by Ministerio de Economia y Competitividad (MINECO) and by European Regional Development Funds (ERDF) of European Union.Gutiérrez Cano, JD.; Catalá Civera, JM.; Plaza González, PJ.; Penaranda-Foix, FL. (2021). Detection of Anti-Counterfeiting Markers through Permittivity Maps Using a Micrometer Scale near Field Scanning Microwave Microscope. Sensors. 21(16):1-14. https://doi.org/10.3390/s21165463S114211

Dynamic measurement of dielectric properties of food snack pellets during microwave expansion

[EN] The in situ dielectric properties of a starch-based food pellet have been measured during microwave expansion. A dual-mode cylindrical cavity allowed simultaneous microwave heating and dielectric measurements of a single pellet inside a quartz tube, ensuring uniform heating during microwave processing. The cavity included additional measurement devices to correlate the dielectric properties with the main parameters of the expansion process, such as temperature, expansion time, pellet volume and absorbed power. A commercially available snack food pellet was Used as the test material for expansion experiments. Results indicated that dielectric constant (epsilon') and loss factor (epsilon") increased during heating, reaching a threshold value of epsilon' = 12.5 and epsilon" = 5.2, around a temperature of 115 degrees C when the material expanded and the dielectric properties dropped abruptly due to the loss of water content and the increase in size. This measurement procedure may provide useful material science information to improve the overall design of starch-based food pellets processed by microwaves. (C) 2017 Elsevier Ltd. All rights reserved.The work presented in this paper was funded by PepsiCo R&D.Gutiérrez Cano, JD.; Catalá Civera, JM.; Bows, J.; Penaranda-Foix, FL. (2017). Dynamic measurement of dielectric properties of food snack pellets during microwave expansion. Journal of Food Engineering. 202:1-8. https://doi.org/10.1016/j.jfoodeng.2017.01.021S1820

Optimizing Phase Settings of High-Frequency Voltage Regulators for Power Delivery Applications

Every new computer server introduced to the market aims at delivering the best tradeoff between performance and power consumption. This goal is crucial in the case of servers for cloud computing hardware infrastructure. In this context, power delivery (PD) experts are adopting higher frequency switching voltage regulators (VR) to reduce platform’s cost as well as total cost of ownership (TCO). Because of this fact, the real estate of components, such as voltage regulators and output inductors, is shrinking as VR frequency increases. As a consequence, achieving the best performance of the VR implies looking into phase shedding schemes, as well as EM coupled inductor design, among other techniques, to mitigate power losses. This paper focuses on the study of the best angle arrangement possible for high frequency VR applications, by exploring angle settings under light load scenarios, aiming to minimize VR’s power loss and output’s voltage ripple

Niche differentiation mechanisms among canopy frugivores and zoochoric trees in the northeastern extreme of the Amazon

Frugivores and zoocoric trees represent an important proportion of tropical rainforest biodiversity. As niche differences favor species coexistence, we aimed to evaluate morphological and temporal niche segregation mechanisms among zoochoric trees and canopy frugivores in a tropical rainforest in the northeastern extreme of the Brazilian Amazon. We tested the effects of fruit morphology, tree size, frugivore body size and time of day on fruit consumption. We recorded the frugivore species that fed on 72 trees (44 species, 22 genera) and whether these frugivores swallowed the seeds. We monitored trees only once from 07:00 to 17:00 h between January and September 2017. We observed fruit consumption in 20 of the 72 trees. Seventy-three frugivore individuals from 22 species visited the trees. Heavier fruits were consumed by larger frugivores, while seed size was inversely correlated with frugivore size. Narrower fruits and fruits with smaller seeds had greater probability of having their seeds ingested, and larger frugivores were more prone to ingest seeds. Trees bearing fruits with smaller seeds were visited by a greater number of frugivores. Taxonomic groups differed in the time of arrival at fruiting trees. None of the evaluated variables (fruit weight and size, and seed size) affected the richness of frugivores that visited the trees. We concluded that, in the studied forest, fruit morphology (weight, size and seed size) is a niche segregation mechanism among zoochoric trees, while body size and time of day are niche segregation mechanisms among frugivores.info:eu-repo/semantics/publishedVersio