17,903 research outputs found
Behavioral modeling of digital IC input and output ports
This paper addresses the development of accurate and efficient behavioral models of digital integrated circuit input and output ports for signal integrity simulations and timing analyses. The modeling process is described and applied to the characterization of actual device
Behavioral Modeling of IC Ports Including Temperature Effects
The development of temperature-dependent macromodels for digital IC ports is addressed. The proposed modeling approach is based on the theory of discrete-time parametric models and allows one to estimate the model parameters from voltage and current waveforms observed at the ports and to implement the model as a SPICE subcircuit. The proposed technique is validated by applying it to commercial devices described by detailed transistor-level models. The obtained models perform at a good accuracy level and are more efficient than the original transistor-level models
Renewable build-up pathways for the US: Generation costs are not system costs
The transition to a future electricity system based primarily on wind and
solar PV is examined for all regions in the contiguous US. We present optimized
pathways for the build-up of wind and solar power for least backup energy needs
as well as for least cost obtained with a simplified, lightweight model based
on long-term high resolution weather-determined generation data. In the absence
of storage, the pathway which achieves the best match of generation and load,
thus resulting in the least backup energy requirements, generally favors a
combination of both technologies, with a wind/solar PV energy mix of about
80/20 in a fully renewable scenario. The least cost development is seen to
start with 100% of the technology with the lowest average generation costs
first, but with increasing renewable installations, economically unfavorable
excess generation pushes it toward the minimal backup pathway. Surplus
generation and the entailed costs can be reduced significantly by combining
wind and solar power, and/or absorbing excess generation, for example with
storage or transmission, or by coupling the electricity system to other energy
sectors.Comment: 11 pages, 6 figure
Macromodeling strategy for digital devices and interconnects
International audienceThis paper proposes a macromodeling approach for the simulation of digital interconnected systems. Such an approach is based on a set of macromodels describing IC ports, IC packages and multiconductor interconnect structures in standard circuit simulators, like SPICE. We illustrate the features of the macromodels and we demonstrate the proposed approach on a realistic simulation problem
Make the Most Out of Your Net: Alternating Between Canonical and Hard Datasets for Improved Image Demosaicing
Image demosaicing is an important step in the image processing pipeline for
digital cameras, and it is one of the many tasks within the field of image
restoration. A well-known characteristic of natural images is that most patches
are smooth, while high-content patches like textures or repetitive patterns are
much rarer, which results in a long-tailed distribution. This distribution can
create an inductive bias when training machine learning algorithms for image
restoration tasks and for image demosaicing in particular. There have been many
different approaches to address this challenge, such as utilizing specific
losses or designing special network architectures. What makes our work is
unique in that it tackles the problem from a training protocol perspective. Our
proposed training regime consists of two key steps. The first step is a
data-mining stage where sub-categories are created and then refined through an
elimination process to only retain the most helpful sub-categories. The second
step is a cyclic training process where the neural network is trained on both
the mined sub-categories and the original dataset. We have conducted various
experiments to demonstrate the effectiveness of our training method for the
image demosaicing task. Our results show that this method outperforms standard
training across a range of architecture sizes and types, including CNNs and
Transformers. Moreover, we are able to achieve state-of-the-art results with a
significantly smaller neural network, compared to previous state-of-the-art
methods
Effects of a saponin fraction extracted from Trigonella foenum-graecum L. and two commercially available saponins on sex ratio and gonad histology of Nile tilapa fry, Oreochromis niloticus (L.)
Over three million tonnes (t) of tilapia, mostly Nile tilapia (Oreochromis niloticus, L.), are produced annually making it the second most abundantly produced freshwater fish (FAO, 2010). Tilapia are mouthbreeders that often produce stunted populations under pond conditions; one means of prevention is to produce all-male fish with the additional advantage that males usually grow faster than females. All-male populations can be achieved by supplementing feed with androgens such as 17-α-Methyltestosterone (MT) during days 10–25 post-hatch (Pandian and Sheela, 1995). However, MT is considered to be carcinogenic (Velazquez and Alter, 2004), and Hulak et al. (2008) also showed that effluents of systems in which carp were fed diets containing MT caused masculinization of female fish. Furthermore, in aquaculture the application of hormones to fish destined for human consumption is prohibited in the European Union under directive 96/22/EC, article 5, which also prohibits import of animal products produced with hormones.
Kwon et al. (2000) showed that Fadrozole, a non-steroidal compound, caused masculinization in tilapia by inhibiting aromatase, which is the enzyme responsible for the conversion of endogenous androgens to estrogens. Steinbronn et al. (2004) were able to show that a dose of 2000 ppm Quillaja saponins (Sigma S-2149) inhibited reproduction of tilapia after dietary application for 32 days to first-feeding fry, suggesting saponins as a possible alternative to MT. These secondary plant compounds consist of either a steroid or triterpenoid basic structure (aglycone or sapogenin) plus one or more sugar side chains (Francis et al., 2002a).
In a previous experiment a saponin fraction from the soapbark tree (Quillaja saponaria M.) inhibited aromatase in vitro (Golan et al., 2008). The fenugreek plant (Trigonella foenum-graecum L), widely cultivated in the Middle East and Asia, also has a high saponin content. The experiment was therefore conducted to test whether saponin fractions from Q. saponaria and from T. foenum-graecum were able to influence the sex ratio and gonad histology of Nile tilapia
Origin of Unexpected Low Energy Structure in Photoelectron Spectra Induced by Mid-Infrared Strong Laser Fields
Using a semiclassical model which incorporates tunneling and Coulomb field
effects, the origin of the unexpected low-energy structure (LES) in
above-threshold ionization spectrum observed in recent experiments [C. I. Blaga
et al., Nature Phys. {\bf 5}, 335 (2009) and W. Quanet al., Phys. Rev. Lett.
{\bf 103}, 093001 (2009)] is identified. We show that the LES arises due to an
interplay between multiple forward scattering of an ionized electron and the
electron momentum disturbance by the Coulomb field immediately after the
ionization. The multiple forward scattering is mainly responsible for the
appearance of LES, while the initial disturbance mainly determines the position
of the LES peaks. The scaling laws for the LES parameters, such as the contrast
ratio and the maximal energy, versus the laser intensity and wavelength are
deduced
Relativistic ionization-rescattering with tailored laser pulses
The interaction of relativistically strong tailored laser pulses with an
atomic system is considered. Due to a special tailoring of the laser pulse, the
suppression of the relativistic drift of the ionized electron and a dramatic
enhancement of the rescattering probability is shown to be achievable. The high
harmonic generation rate in the relativistic regime is calculated and shown to
be increased by several orders of magnitude compared to the case of
conventional laser pulses. The energies of the revisiting electron at the
atomic core can approach the MeV domain, thus rendering hard x-ray harmonics
and nuclear reactions with single atoms feasible
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