scholarly journals Temporal Variation in Cultural Seismic Noise and Noise Correlation Functions during COVID-19 Lockdown in Canada

2021 ◽  
Author(s):  
Ayodeji Paul Kuponiyi ◽  
Honn Kao
Keyword(s):  
Correlation Functions ◽  
Seismic Noise ◽  
Signal Quality ◽  
Western Canada ◽  
Eastern Canada ◽  
Similar Time ◽  
Period Range ◽  
Short Period ◽  
Station Pair

Abstract The COVID-19 pandemic of 2020 led to a widespread lockdown that restricted human activities, particularly land, air, and maritime traffic. The “quietness” on land and ocean that followed presents an opportunity to measure an unprecedented reduction in human-related seismic activities and study its effect on the short-period range of ambient noise cross-correlation functions (NCFs). We document the variations in seismic power levels and signal quality of short-period NCFs measured by four seismographs located near Canadian cities across the pandemic-defined timeline. Significant drops in seismic power levels are observed at all the locations around mid-March. These drops coincide with lockdown announcements by the various Canadian provinces where the stations are located. Mean seismic power reductions of ∼24% and ∼17% are observed near Montreal and Ottawa, respectively, in eastern Canada. Similar reductions of ∼27% and 17% are recorded in western Canada near Victoria and Sidney, respectively. None of the locations show full recovery in seismic power back to the pre-lockdown levels by the end of June, when the provinces moved into gradual reopening. The overall levels of seismic noise during lockdown are a factor of 5–10 lower at our study locations in western Canada, relative to the east. Signal quality of NCF measured in the secondary microseism frequency band for the station pair in western Canada is maximum before lockdown (late February–early March), minimum during lockdown (mid–late March), and increased to intermediate levels in the reopening phase (late May). A similar pattern is observed for the signal quality of the eastern Canada station pair, except for a jump in levels at similar periods during the lockdown phase. The signal quality of NCF within the secondary microseism band is further shown to be the lowest for the western Canada station pair during the 2020 lockdown phase, when compared with similar time windows in 2018 and 2019.

Short-period seismic noise

1967 ◽  
Vol 57 (1) ◽  
pp. 55-81
Author(s):  
E. J. Douze
Keyword(s):  
Surface Waves ◽  
Rayleigh Waves ◽  
Seismic Noise ◽  
Body Waves ◽  
Deep Hole ◽  
Period Range ◽  
Short Period ◽  
The Subject ◽  
Hole Arrays

abstract This report consists of a summary of the studies conducted on the subject of short-period (6.0-0.3 sec period) noise over a period of approximately three years. Information from deep-hole and surface arrays was used in an attempt to determine the types of waves of which the noise is composed. The theoretical behavior of higher-mode Rayleigh waves and of body waves as measured by surface and deep-hole arrays is described. Both surface and body waves are shown to exist in the noise. Surface waves generally predominate at the longer periods (of the period range discussed) while body waves appear at the shorter periods at quiet sites. Not all the data could be interpreted to define the wave types present.

Physical and topographic factors as related to short-period wind noise

1965 ◽  
Vol 55 (5) ◽  
pp. 863-877 ◽  
Author(s):  
Herbert Robertson
Keyword(s):  
Wind Direction ◽  
Seismic Noise ◽  
Wind Noise ◽  
Period Range ◽  
Topographic Factors ◽  
Short Period ◽  
Granite Outcrop ◽  
Topographic Shielding

abstract Median values of seismic noise in the period range of 0.3 to 1.3 sec were obtained from recordings at vaults of the Pole Mountain and WMSO arrays. Interquartile ranges were used to measure dispersions about the medians. Medians of the noise at Pole Mountain ranged from 0.91 mµ to 2.20 mµ in November 1962. The former value was obtained for a vault that was located in dense granite at the base of a massive granite outcrop; the latter value was obtained for a vault in a slab of dense granite located on a grassy plain. This indicated that topographic shielding from wind rather than density of bedrock affected noise. As a test of this idea, wind protection numbers were assigned to vaults Z1 through Z9 of the WMSO array based on comparative topographic shielding with respect to a known wind direction. Noise values increased as wind numbers decreased. Topographic protection and vault construction limited wind noise at WMSO.

The High-Frequency Decay Slope of Spectra (Kappa) for M≥3.5 Earthquakes on Rock Sites in Eastern and Western Canada

2020 ◽  
Vol 110 (2) ◽  
pp. 471-488 ◽  
Author(s):  
Samantha M. Palmer ◽  
Gail M. Atkinson
Keyword(s):  
Ground Motion ◽  
Classical Method ◽  
Vertical Component ◽  
Western Canada ◽  
S Wave ◽  
Motion Modeling ◽  
Eastern Canada ◽  
General Observation ◽  
Anelastic Attenuation ◽  
Two Parameters

ABSTRACT Spectral decay of ground-motion amplitudes at high frequencies is primarily influenced by two parameters: site-related kappa (κ0) and regional Q (quality factor, inversely proportional to anelastic attenuation). We examine kappa and apparent Q-values (Qa) for M≥3.5 earthquakes recorded at seismograph stations on rock sites in eastern and western Canada. Our database contains 20 earthquakes recorded on nine stations in eastern Canada and 404 earthquakes recorded on eight stations in western Canada, resulting in 105 and 865 Fourier amplitude spectra, respectively. We apply two different methods: (1) a modified version of the classical S-wave acceleration method; and (2) a new stacking method that is consistent with the use of kappa in ground-motion modeling. The results are robust with respect to the method used and also with respect to the frequency band selected, which ranges from 9 to 38 Hz depending on the region, event, and method. Kappa values obtained from the classical method are consistent with those of the stacked method, but the stacked method provides a lower uncertainty. A general observation is that kappa is usually larger, and apparent Q is smaller, for the horizontal component in comparison to the vertical component. We determine an average regional κ0=7  ms (horizontal) and 0 ms (vertical) for rock sites in eastern Canada; we obtain κ0=19  ms (horizontal) and 14 ms (vertical) for rock sites in western Canada. We note that kappa measurements are quite sensitive to details of data selection criteria and methodology, and may be significantly influenced by site effects, resulting in large site-to-site variability.

scholarly journals The Optical Signal-to-Crosstalk Ratio for the MBA(N, e, g) Switching Fabric †

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1534
Author(s):  
Remigiusz Rajewski
Keyword(s):  
Optical Switching ◽  
Essential Feature ◽  
Optical Signal ◽  
Point Of View ◽  
Signal Quality ◽  
Switching Networks ◽  
Optical Elements ◽  
Optical Signals ◽  
Switching Fabric

The banyan-type switching networks, well known in switching theory and called the logdN switching fabrics, are composed of symmetrical switching elements of size d×d. In turn, the modified baseline architecture, called the MBA(N,e,g), is only partially built from symmetrical optical switching elements, and it is constructed mostly from asymmetrical optical switching elements. Recently, it was shown that the MBA(N,e,g) structure requires a lower number of passive as well as active optical elements than the banyan-type switching fabric of the same capacity and functionality, which makes it an attractive solution. However, the optical signal-to-crosstalk ratio for the MBA(N,e,g) was not investigated before. Therefore, in this paper, the optical signal-to-crosstalk ratio in the MBA(N,e,g) was determined. Such crosstalk influences the output signal’s quality. Thus, if such crosstalk is lower, the signal quality is better. The switching fabric proposed in the author’s previous work has lower optical signal losses than a typical Beneš and banyan-type switching networks of this same capacity and functionality, which gives better quality of transmitted optical signals at the switching node’s output. The investigated MBA(N,e,g) architecture also contains one stage fewer than banyan-type network of the same capacity, which is an essential feature from the optical switching point of view.

Kernel colour varies with cultivars and environments in barley

1998 ◽  
Vol 78 (2) ◽  
pp. 217-222 ◽  
Author(s):  
M. J. Edney ◽  
T. M. Choo ◽  
D. Kong ◽  
T. Ferguson ◽  
K. M. Ho ◽  
...  
Keyword(s):  
Hordeum Vulgare ◽  
Key Words ◽  
Western Canada ◽  
Net Blotch ◽  
Hordeum Vulgare L ◽  
Eastern Canada ◽  
Key Words Barley

Kernel colour is an important marketing trait for both malting and feed barleys. Therefore a study was initiated to investigate the kernel colour of 75 Canadian barley (Hordeum vulgare L.) cultivars at three locations (Charlottetown, Ottawa and Bentley) across Canada in 1991 and 1992. Kernel colour was measured by an Instrumar Colormet Spectrocolorimeter. Kernel colour was found to be brighter at the two locations in eastern Canada (Charlottetown and Ottawa) than at the location in western Canada (Bentley). Two-row cultivars on average were more discoloured than six-row cultivars; eastern two-row were more discoloured than western two-row. Covered barleys were less discoloured than hulless barleys in five of the six environments, but covered barleys at Bentley in 1992 were more discoloured than hulless barleys. Kernel discolouration appeared to be associated with susceptibility to net blotch for six-row cultivars. More studies are needed on kernel discolouration of barley. Key words: Barley, Hordeum vulgare, kernel colour

Risks of the Digitalization of Life of the Population and Ways of Decreasing Them

2021 ◽  
Vol 13 (4-1) ◽  
pp. 180-203
Author(s):  
Elena Stukalenko ◽  
Keyword(s):  
Quality Of Life ◽  
Digital Technologies ◽  
Well Being ◽  
Digital Economy ◽  
Digital Transformation ◽  
Negative Consequences ◽  
Short Period ◽  
The World ◽  
The Impact

Digital technologies, ubiquitous in our daily life, have radically changed the way we work, communicate, and consume in a short period of time. They affect all components of quality of life: well-being, work, health, education, social connections, environmental quality, the ability to participate and govern civil society, and so on. Digital transformation creates both opportunities and serious risks to the well-being of people. Researchers and statistical agencies around the world are facing a major challenge to develop new tools to analyze the impact of digital transformation on the well-being of the population. The risks are very diverse in nature and it is very difficult to identify the key factor. All researchers conclude that secure digital technologies significantly improve the lives of those who have the skills to use them and pose a serious risk of inequality for society, as they introduce a digital divide between those who have the skills to use them and those who do not. In the article, the author examines the risks created by digital technologies for some components of the quality of life (digital component of the quality of life), which are six main components: the digital quality of the population, providing the population with digital benefits, the labor market in the digital economy, the impact of digitalization on the social sphere, state electronic services for the population and the security of information activities. The study was carried out on the basis of the available statistical base and the results of research by scientists from different countries of the world. The risks of the digital economy cannot be ignored when pursuing state social policy. Attention is paid to government regulation aimed at reducing the negative consequences of digitalization through the prism of national, federal projects and other events.

Approximate method to estimate the short-period strong motion spectra on bedrock

1981 ◽  
Vol 71 (2) ◽  
pp. 491-505
Author(s):  
Katsuhiko Ishida
Keyword(s):  
Earthquake Swarm ◽  
Strong Motion ◽  
Fourier Amplitude ◽  
Period Range ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Short Period ◽  
Amplitude Spectra ◽  
Low Pass ◽  
Parkfield Earthquake

abstract The methodology to estimate the strong motion Fourier amplitude spectra in a short-period range (T ≦ 1 to 2 sec) on a bedrock level is discussed in this paper. The basic idea is that the synthetic strong motion Fourier spectrum F˜A(ω) calculated from smoothed rupture velocity model (Savage, 1972) is approximately similar to that of low-pass-filtered strong earthquake ground motion at a site in a period range T ≧ 1 to 2 sec: F˜A(ω)=B˜(ω)·A(ω). B˜(ω) is an observed Fourier spectrum on a bedrock level and A(ω) is a low-pass filter. As a low-pass filter, the following relation, A ( T ) = · a · T n a T n + 1 , ( T = 2 π / ω ) , is assumed. In order to estimate the characteristic coefficients {n} and {a}, the Tokachi-Oki earthquake (1968), the Parkfield earthquake (1966), and the Matsushiro earthquake swarm (1966) were analyzed. The results obtained indicate that: (1) the coefficient {n} is nearly two for three earthquakes, and {a} is nearly one for the Tokachi-Oki earthquake, eight for the Parkfield earthquake, and four for the Matsushiro earthquake swarm, respectively; (2) the coefficient {a} is related with stress drop Δσ as (a = 0.07.Δσ). Using this relationship between {a} and Δσ, the coefficients {a} of past large earthquakes were estimated. The Fourier amplitude spectra on a bedrock level are also estimated using an inverse filtering method of A ( T ) = a T 2 a T 2 + 1 .

МЕТОД ГЛУБОКОГО ОБУЧЕНИЯ С ПОДКРЕПЛЕНИЕМ ДЛЯ СИСТЕМ ИНТЕРНЕТА ВЕЩЕЙ НА БАЗЕ ТЕХНОЛОГИИ LORA С ОГРАНИЧЕННЫМИ РЕСУРСАМИ И ПОДДЕРЖКОЙ QoS

2021 ◽  
Author(s):  
 M.S. MUTHANNA ◽  
A.S. MUTHANNA ◽  
 A.S. BORODIN
Keyword(s):  
Data Transmission ◽  
Environmental Parameters ◽  
Code Rate ◽  
Frame Structure ◽  
Signal Quality ◽  
High Quality ◽  
Spreading Factor ◽  
Transmission Parameters ◽  
Factor Code

Achieving high Quality of Service (QoS) remains a challenge for LoRa technology. However, high QoS can be achieved via optimizing the transmission policy parameters such as bandwidth and code rate. Existing approaches do not provide an opportunity to optimize the LoRa networks' data transmission parameters. The article proposes transmission policy enforcementfor QoS-aware LoRanetworks.The QoSparameter ranking is implemented for IoT nodes where priority and nonpriority information is identified by the new field of LoRa frame structure(QRank).The optimaltransmissionpolicyenforcement uses fast deep reinforcement learning that utilizes the environmental parameters including QRank, signal quality, and signal-to-interference-plus-noise-ratio. The transmission policy is optimized for spreading factor, code rate, bandwidth, and carrier frequency. Performance evaluation is implemented using an NS3.26 LoRaWAN module. The performance is examined for various metrics such as delay and throughput. Достижение высокого качества обслуживания (QoS) по-прежнему остается достаточно сложной задачей для технологии LoRa. В принципе высокий уровень QoS может быть достигнут за счет оптимизации параметров передачи, например, пропускной способности и скорости передачи информации в сети. Известные на сегодняшний день решения не дают возможности оптимизировать параметры передачи данных для сетей LoRa. В статье предложен эффективный метод передачи данных, обеспечивающий требования по QoS при использовании технологии LoRa. Ранжирование параметров QoS для узлов интернета вещей определяется новым полем структуры фрейма LoRa (QRank) для приоритетной и неприоритетной информации. Для обеспечения эффективной передачи применяется быстрое глубокое обучение с подкреплением, для которого используются как параметры качества обслуживания, так и отношение сигнал/шум. Метод передачи оптимизирован с учетом коэффициента распространения, скорости передачи данных, полосы пропускания и несущей частоты. Оценка производительности при применении предложенного метода проведена с использованием модуля LoRaWAN в пакете имитационного моделирования NS3.26. Производительность оценивается на основе параметров задержки и пропускной способности.

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