Trade‐Offs in Parameters Describing Crustal Heterogeneity and Intrinsic Attenuation from Radiative Transport Modeling of High‐Frequency Regional Seismograms

2019 ◽  
Vol 109 (1) ◽  
pp. 312-321 ◽  
Author(s):  
Vernon F. Cormier ◽  
Christopher J. Sanborn
Keyword(s):  
High Frequency ◽  
Transport Modeling ◽  
Radiative Transport ◽  
Intrinsic Attenuation ◽  
Trade Offs ◽  
Crustal Heterogeneity

scholarly journals Evolutionary trade-offs and the structure of polymorphisms

2018 ◽  
Vol 373 (1747) ◽  
pp. 20170105 ◽  
Author(s):  
Hila Sheftel ◽  
Pablo Szekely ◽  
Avi Mayo ◽  
Guy Sella ◽  
Uri Alon
Keyword(s):  
High Frequency ◽  
Cell Biology ◽  
Pareto Front ◽  
Complex Structure ◽  
Self Organization ◽  
Theme Issue ◽  
Single Task ◽  
Trade Offs ◽  
Simple Geometry ◽  
Multiple Tasks

Populations of organisms show genetic differences called polymorphisms. Understanding the effects of polymorphisms is important for biology and medicine. Here, we ask which polymorphisms occur at high frequency when organisms evolve under trade-offs between multiple tasks. Multiple tasks present a problem, because it is not possible to be optimal at all tasks simultaneously and hence compromises are necessary. Recent work indicates that trade-offs lead to a simple geometry of phenotypes in the space of traits: phenotypes fall on the Pareto front, which is shaped as a polytope: a line, triangle, tetrahedron etc. The vertices of these polytopes are the optimal phenotypes for a single task. Up to now, work on this Pareto approach has not considered its genetic underpinnings. Here, we address this by asking how the polymorphism structure of a population is affected by evolution under trade-offs. We simulate a multi-task selection scenario, in which the population evolves to the Pareto front: the line segment between two archetypes or the triangle between three archetypes. We find that polymorphisms that become prevalent in the population have pleiotropic phenotypic effects that align with the Pareto front. Similarly, epistatic effects between prevalent polymorphisms are parallel to the front. Alignment with the front occurs also for asexual mating. Alignment is reduced when drift or linkage is strong, and is replaced by a more complex structure in which many perpendicular allele effects cancel out. Aligned polymorphism structure allows mating to produce offspring that stand a good chance of being optimal multi-taskers in at least one of the locales available to the species. This article is part of the theme issue ‘Self-organization in cell biology’.

THEORETICAL AND EXPERIMENTAL EVALUATION OF THE PHASE NOISE BEHAVIOR OF A DUAL-LOOP FREQUENCY SYNTHESIZER FOR 5-GHz WLANs

2007 ◽  
Vol 16 (04) ◽  
pp. 577-588
Author(s):  
FOTIS PLESSAS ◽  
SOFIA VATTI ◽  
GRIGORIOS KALIVAS
Keyword(s):  
Phase Noise ◽  
Linear Model ◽  
High Frequency ◽  
Experimental Evaluation ◽  
Frequency Synthesizer ◽  
Transfer Functions ◽  
Prototype System ◽  
Discrete Elements ◽  
Trade Offs ◽  
5 Ghz

This paper presents the analysis and experimental evaluation of a modified dual-loop phase-locked loop synthesizer, using the phase noise transfer functions resulting from the linear model of the synthesizer. The different arrangement in the high-frequency loop, in contrast to previous reported series-connected dual-loop topologies, offers various advantages, such as improved phase noise, finer resolution, and lower spurious levels. Discrete elements are used to implement a prototype system for testing. This adds to the flexibility of the design and allows for experimental optimization of the loop trade-offs. The synthesizer generates signals in the 4850 MHz to 5050 MHz range with a 10 MHz resolution and can match the specifications for wireless LANs operating at 5 GHz. The design resulted in a prototype with very good characteristics suitable for future integration.

High-frequency spectra observed at Anza, California: Implications for Q structure

1988 ◽  
Vol 78 (2) ◽  
pp. 692-707
Author(s):  
S. E. Hough ◽  
J. G. Anderson
Keyword(s):  
High Frequency ◽  
P Waves ◽  
Frequency Spectra ◽  
S Waves ◽  
Intrinsic Attenuation ◽  
Depth Dependence ◽  
Wide Range ◽  
Distance Dependence ◽  
Attenuation Mechanism ◽  
Inversion Procedure

Abstract Data from the Anza array in southern California have been analyzed to yield a model for the depth dependence of attenuation. The result is obtained from a formal inversion of the distance dependence of the spectral decay parameter, κ, observed from sources at a wide range of distances from single stations. The inversion procedure assumes constant Qi in plane layers and finds models which are as nearly constant with depth as possible. We find that the data cannot be explained by a model in which Qi is constant with depth and that the data generally require three-layer models. The resulting models typically give Qi for P waves between 300 and 1000 in the top 5 km, rising to 1000 to 3000 at greater depths, and decreasing to 700 to 1000 around 12 km depth. Qi for S waves is slightly higher in most cases. Because this depth dependence of Qi is generally correlated with the depths of earthquake epicenters, we suggest that Qi may be due to a pressure and temperature-controlled intrinsic attenuation mechanism.

scholarly journals Scattering Attenuation of the Martian Interior through Coda-Wave Analysis

2021 ◽  
Author(s):  
Foivos Karakostas ◽  
Nicholas Schmerr ◽  
Ross Maguire ◽  
Quancheng Huang ◽  
Doyeon Kim ◽  
...  
Keyword(s):  
High Frequency ◽  
Low Frequency ◽  
Scattered Wave ◽  
Coda Wave ◽  
Very High Frequency ◽  
Scattering Layer ◽  
Scattering Attenuation ◽  
Trade Offs ◽  
Scattering Strength ◽  
Diffusive Layer

ABSTRACT We investigate the scattering attenuation characteristics of the Martian crust and uppermost mantle to understand the structure of the Martian interior. We examine the energy decay of the spectral envelopes for 21 high-quality Martian seismic events from sols 128 to 500 of InSight operations. We use the model of Dainty, Toksöz, et al. (1974) to approximate the behavior of energy envelopes resulting from scattered wave propagation through a single diffusive layer over an elastic half-space. Using a grid search, we mapped the layer parameters that fit the observed InSight data envelopes. The single diffusive layer model provided better fits to the observed energy envelopes for high-frequency (HF) and very-high-frequency (VF) than for the low-frequency and broadband events. This result is consistent with the suggested source depths (Giardini et al., 2020) for these families of events and their expected interaction with a shallow scattering layer. The shapes of the observed data envelopes do not show a consistent pattern with event distance, suggesting that the diffusivity and scattering layer thickness is nonuniform in the vicinity of InSight at Mars. Given the consistency in the envelope shapes between HF and VF events across epicentral distances and the trade-offs between the parameters that control scattering, the dimensions of the scattering layer remain unconstrained but require that scattering strength decreases with depth and that the rate of decay in scattering strength is the fastest near the surface. This is generally consistent with the processes that would form scattering structures in planetary lithospheres.

High Frequency Base Materials: Laser-Material Interaction for HDI/ICP Applications

2018 ◽  
Vol 2018 (1) ◽  
pp. 000277-000292 ◽  
Author(s):  
Christopher Ryder ◽  
Geoffrey Lott ◽  
Ruolin Chen ◽  
Nicolas Falletto
Keyword(s):  
Integrated Circuit ◽  
High Frequency ◽  
Base Material ◽  
Autonomous Driving ◽  
Industrial Applications ◽  
Conclusive Evidence ◽  
Laser Material ◽  
Base Materials ◽  
Trade Offs ◽  
Practical Guidelines

Abstract High frequency (HF) applications are nothing new. Nor are the multitudes of materials and processes in electronics dedicated to such applications. But with the rising applications and production volumes associated with 5G, IoT (Internet of Things), autonomous driving, and the like, a whole new emphasis is needed to characterize expected base material performance in terms of its processability. Laser-based manufacturing, and in particular laser via drilling, plays a large role in the interconnect and packaging concepts needed for the typically miniaturized design rules, but given the diversity of materials and laser types that can potentially be employed, some clear results-driven guidelines would be beneficial to manufacturers looking to optimize a cost/quality/throughput balance. In this paper we explore laser-based via drilling applications with base materials intended for use in high frequency end applications. There are several HF base material sets employed in HDI (High Density Interconnect)/ICP (Integrated Circuit Packaging) manufacturing, each with their own range of bandwidth and applicable dielectric constant. However, agnostic of the particular material application specifications, the aim of this analysis is to explore potential manufacturing benefits and/or trade-offs for diverse laser/material interactions, while focusing on via-drilling for the HDI and ICP industries in particular. Benefits and trade-offs are characterized by practical and quantifiable elements, precisely: throughput (vias per second), quality (roundness, burr, dimensional integrity, etc). In combination with various laser types, in particular UV (nanosecond), CO2 (microsecond) and green (femtosecond) wavelengths, we analyze the fundamental interaction with materials common to high frequency applications, namely LCP (Liquid Crystal Polymer), PTFE (Polytetrafluoroethylene), HF FR4, and PI (Polyimide) in an effort to attain practical guidelines for quality and manufacturability. Thus, evidence is provided to potentially increase manufacturing yield with a typically cost-inhibitive material set. Given the, as yet, novel usage of such materials for broadband HDI/ICP applications, this work aims to explore new or re-affirmed baselines suitable to the existing production landscape. Given the broad scope of potential DoE parameters, this work focuses on target via size (75um) applicable to multiple industrial applications, including but not exclusive to, handheld communications, automotive and IoT. Furthermore, the materials is clad with a 12um Cu foil to offer insight into ablation capabilities of each laser type. As a test vehicle default, the vias are drilled in a standard BGA (Ball Grid Array) grid with a pitch of 0.6mm. The results of this work offer-a scored matrix breakdown of our predetermined criteria (throughput, quality) to the laser-material subset analyzed. Given the non-exhaustive nature of this study, the conclusions do not aim to resolve laser-material dilemmas for all forms and factors of high frequency applications and material configurations, but rather offer conclusive evidence that a) high-frequency materials typically require special attention when processing with laser, b) not every laser type works at the same rate of efficiency and efficacy for each of the chosen HF materials and c) a cost/quality balance can be sought by cross referencing results from various laser sources for the intended application.

scholarly journals Territorial black-capped chickadee males respond faster to high- than to low-frequency songs in experimentally elevated noise conditions

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e3257 ◽  
Author(s):  
Stefanie E. LaZerte ◽  
Hans Slabbekoorn ◽  
Ken A. Otter
Keyword(s):  
High Frequency ◽  
Background Noise ◽  
Noise Exposure ◽  
Signal To Noise Ratio ◽  
Low Frequency ◽  
Trade Offs ◽  
Dependent Signal ◽  
Noisy Conditions ◽  
Carry Over ◽  
Free Ranging

Low-frequency urban noise can interfere with avian communication through masking. Some species are able to shift the frequency of their vocalizations upwards in noisy conditions, which may reduce the effects of masking. However, results from playback studies investigating whether or not such vocal changes improve audibility in noisy conditions are not clear; the responses of free-ranging individuals to shifted signals are potentially confounded by functional trade-offs between masking-related audibility and frequency-dependent signal quality. Black-capped chickadees (Poecile atricapillus) naturally sing their songs at several different frequencies as they pitch-shift to match conspecifics during song-matching contests. They are also known to switch to higher song frequencies in response to experimental noise exposure. Each male produces both high- and low-frequency songs and absolute frequency is not a signal of aggression or dominance, making this an interesting species in which to test whether higher-frequency songs are more audible than lower-frequency songs in noisy conditions. We conducted playback studies across southern and central British Columbia, Canada, using paired song stimuli (high- vs low-frequency songs, n = 24 pairs) embedded in synthetic background noise created to match typical urban sound profiles. Over the course of each playback, the signal-to-noise ratio of the song stimuli was gradually increased by raising the amplitude of the song stimuli while maintaining background noise at a constant amplitude. We evaluated variation in how quickly and aggressively territorial males reacted to each of the paired stimuli. We found that males responded more quickly to playbacks of high- than low-frequency songs when high-frequency songs were presented first, but not when low-frequency songs were first. This difference may be explained by high-frequency songs being more audible combined with a carry-over effect resulting in slower responses to the second stimulus due to habituation. We observed no difference in overall aggression between stimuli. These results suggest that high-frequency songs may be more audible under noisy conditions.

scholarly journals Good-enough production: Selecting easier words instead of more accurate ones

2021 ◽  
Author(s):  
Mark Koranda ◽  
Martin Zettersten ◽  
Maryellen MacDonald
Keyword(s):  
High Frequency ◽  
Low Frequency ◽  
Word Meanings ◽  
Frequency Word ◽  
Trade Off ◽  
Word Use ◽  
Trade Offs ◽  
Language Communication ◽  
The Times ◽  
High Frequency Words

While many implicit decisions are the result of a trade-off, trade-offs in word use, such as whether a producer meant to convey a message more aligned with kitten despite saying a more accessible word like cat, are difficult to measure. To test the trade-off between message alignment and accessibility, we designed an artificial lexicon where word meanings corresponded to angles on a compass. In a novel language communication game, participants trained on some words more than others (high- vs low-frequency), and then earned points by producing words, often requiring an implicit decision between a high- vs low-frequency word. A trade-off was observed across four experiments, such that high-frequency words were produced even when less aligned with messages. Since high-frequency words are more accessible, these results suggest that implicit decisions between words are impacted by accessibility. Of all the times that people have said cat, many times they likely meant kitten.

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