Interpreting erosion frequency and magnitude from luminescence profiles in boulders

2020 ◽  
Author(s):  
Nathan Brown ◽  
Seulgi Moon
Keyword(s):  
Power Law ◽  
Ground Level ◽  
Erosion Rates ◽  
Stochastic Nature ◽  
Wide Range ◽  
Bedrock Erosion ◽  
Instrumental Record ◽  
Simulation Results ◽  
Subcritical Cracking ◽  
Power Law Distributions

<p>Exposed bedrock is ubiquitous on terrestrial and planetary landscapes, yet little is known<br>about the rate of bedrock erosion at a granular scale on timescales longer than the<br>instrumental record. As recently suggested, using the bleaching depth of luminescence<br>signals as a measure of bedrock erosion may fit these scales. Yet this approach assumes<br>constant erosion through time, a condition likely violated by the stochastic nature of erosional<br>events. Here we simulate bleaching in response to power-law distributions of removal<br>lengths and hiatus durations. We compare simulation results with previously measured<br>luminescence profiles from boulder surfaces to illustrate that prolonged hiatuses are unlikely<br>and that typical erosion scales are sub-granular with occasional loss at mm scales,<br>consistent with ideas about microflaws governing bedrock detachment. For a wide range of<br>erosion rates, measurements are integrated over many removal events, producing<br>reasonably accurate estimates despite the stochastic nature of the simulated process. We<br>hypothesize that the greater or equal erosion rates atop large boulders compared to rates at<br>ground level suggest that subcritical cracking may be more influential than aeolian abrasion<br>for boulder degradation in the Eastern Pamirs, China.</p>

On the power-law distribution of language family sizes

2005 ◽  
Vol 41 (1) ◽  
pp. 117-131 ◽  
Author(s):  
SØREN WICHMANN
Keyword(s):  
Power Law ◽  
Rank Order ◽  
Language Family ◽  
Power Law Distribution ◽  
Stochastic Nature ◽  
Wide Range ◽  
The Family ◽  
Rank 2 ◽  
Physical Phenomena ◽  
Power Law Distributions

When the sizes of language families of the world, measured by the number of languages contained in each family, are plotted in descending order on a diagram where the x-axis represents the place of each family in the rank-order (the largest family having rank 1, the next-largest, rank 2, and so on) and the y-axis represents the number of languages in the family determining the rank-ordering, it is seen that the distribution closely approximates a curve defined by the formula y=ax−b. Such ‘power-law’ distributions are known to characterize a wide range of social, biological, and physical phenomena and are essentially of a stochastic nature. It is suggested that the apparent power-law distribution of language family sizes is of relevance when evaluating overall classifications of the world's languages, for the analysis of taxonomic structures, for developing hypotheses concerning the prehistory of the world's languages, and for modelling the future extinction of language families.

scholarly journals POWER-LAW DISTRIBUTIONS IN CIRCULATING MONEY: EFFECT OF PREFERENTIAL BEHAVIOR

2004 ◽  
Vol 18 (17n19) ◽  
pp. 2725-2729 ◽  
Author(s):  
NING DING ◽  
YOUGUI WANG ◽  
JUN XU ◽  
NING XI
Keyword(s):  
Computer Simulation ◽  
Statistical Mechanics ◽  
Power Law ◽  
Power Laws ◽  
Generation Mechanism ◽  
Holding Time ◽  
Simulation Results ◽  
Power Law Distributions ◽  
Money Circulation

We introduce preferential behavior into the study on statistical mechanics of money circulation. The computer simulation results show that the preferential behavior can lead to power laws on distributions over both holding time and amount of money held by agents. However, some constraints are needed in generation mechanism to ensure the robustness of power-law distributions.

scholarly journals Design and Evaluation of Large-Scale IoT-Enabled Healthcare Architecture

2021 ◽  
Vol 11 (8) ◽  
pp. 3623
Author(s):  
Omar Said ◽  
Amr Tolba
Keyword(s):  
Packet Loss ◽  
Large Scale ◽  
Performance Metrics ◽  
Medical System ◽  
Healthcare Data ◽  
High Altitude Platforms ◽  
Wide Range ◽  
Simulation Results ◽  
Healthcare Architecture ◽  
The Internet Of Things

Employment of the Internet of Things (IoT) technology in the healthcare field can contribute to recruiting heterogeneous medical devices and creating smart cooperation between them. This cooperation leads to an increase in the efficiency of the entire medical system, thus accelerating the diagnosis and curing of patients, in general, and rescuing critical cases in particular. In this paper, a large-scale IoT-enabled healthcare architecture is proposed. To achieve a wide range of communication between healthcare devices, not only are Internet coverage tools utilized but also satellites and high-altitude platforms (HAPs). In addition, the clustering idea is applied in the proposed architecture to facilitate its management. Moreover, healthcare data are prioritized into several levels of importance. Finally, NS3 is used to measure the performance of the proposed IoT-enabled healthcare architecture. The performance metrics are delay, energy consumption, packet loss, coverage tool usage, throughput, percentage of served users, and percentage of each exchanged data type. The simulation results demonstrate that the proposed IoT-enabled healthcare architecture outperforms the traditional healthcare architecture.

scholarly journals Research on the Human Dynamics in Mobile Communities Based on Social Identity

2012 ◽  
Vol 2012 ◽  
pp. 1-13 ◽  
Author(s):  
Qiang Yan ◽  
Lianren Wu ◽  
Lanli Yi
Keyword(s):  
Social Identity ◽  
Mobile Phone ◽  
Power Law ◽  
Significant Influence ◽  
Mobile Internet ◽  
Internet Technology ◽  
Power Exponent ◽  
Human Dynamics ◽  
The Social ◽  
Simulation Results

Through analyzing the data about the releases, comment, and forwarding of 120,000 microblog messages in a year, this paper finds out that the intervals between information releases and comment follow a power law; besides, the analysis of data in each 24 hours reveals obvious differences between microblogging and website visit, email, instant communication, and the use of mobile phone, reflecting how people use fragments of time via mobile internet technology. The paper points out the significant influence of the user's activity on the intervals of information releases and thus demonstrates a positive correlation between the activity and the power exponent. The paper also points out that user's activity is influenced by social identity in a positive way. The simulation results based on the social identity mechanism fit well with the actual data, which indicates that this mechanism is a reasonable way to explain people's behavior in the mobile Internet.

scholarly journals Aircraft measurements of gravity waves in the upper troposphere and lower stratosphere during the START08 field experiment

2015 ◽  
Vol 15 (13) ◽  
pp. 7667-7684 ◽  
Author(s):  
Fuqing Zhang ◽  
Junhong Wei ◽  
Meng Zhang ◽  
K. P. Bowman ◽  
L. L. Pan ◽  
...  
Keyword(s):  
Power Law ◽  
Gravity Waves ◽  
Lower Stratosphere ◽  
Potential Temperature ◽  
Shear Instability ◽  
Aircraft Measurements ◽  
Upper Troposphere ◽  
Airborne Measurements ◽  
Wide Range

Abstract. This study analyzes in situ airborne measurements from the 2008 Stratosphere–Troposphere Analyses of Regional Transport (START08) experiment to characterize gravity waves in the extratropical upper troposphere and lower stratosphere (ExUTLS). The focus is on the second research flight (RF02), which took place on 21–22 April 2008. This was the first airborne mission dedicated to probing gravity waves associated with strong upper-tropospheric jet–front systems. Based on spectral and wavelet analyses of the in situ observations, along with a diagnosis of the polarization relationships, clear signals of mesoscale variations with wavelengths ~ 50–500 km are found in almost every segment of the 8 h flight, which took place mostly in the lower stratosphere. The aircraft sampled a wide range of background conditions including the region near the jet core, the jet exit and over the Rocky Mountains with clear evidence of vertically propagating gravity waves of along-track wavelength between 100 and 120 km. The power spectra of the horizontal velocity components and potential temperature for the scale approximately between ~ 8 and ~ 256 km display an approximate −5/3 power law in agreement with past studies on aircraft measurements, while the fluctuations roll over to a −3 power law for the scale approximately between ~ 0.5 and ~ 8 km (except when this part of the spectrum is activated, as recorded clearly by one of the flight segments). However, at least part of the high-frequency signals with sampled periods of ~ 20–~ 60 s and wavelengths of ~ 5–~ 15 km might be due to intrinsic observational errors in the aircraft measurements, even though the possibilities that these fluctuations may be due to other physical phenomena (e.g., nonlinear dynamics, shear instability and/or turbulence) cannot be completely ruled out.

scholarly journals Predicting observational signatures of coronal heating by Alfvén waves and nanoflares

2007 ◽  
Vol 3 (S247) ◽  
pp. 279-287
Author(s):  
Patrick Antolin ◽  
Kazunari Shibata ◽  
Takahiro Kudoh ◽  
Daiko Shiota ◽  
David Brooks
Keyword(s):  
Power Law ◽  
Alfven Waves ◽  
Alfvén Waves ◽  
Power Law Distribution ◽  
Longitudinal Modes ◽  
Heating Mechanism ◽  
Set Up ◽  
Power Law Index ◽  
Power Law Distributions ◽  
Release Processes

AbstractAlfvén waves can dissipate their energy by means of nonlinear mechanisms, and constitute good candidates to heat and maintain the solar corona to the observed few million degrees. Another appealing candidate is the nanoflare-reconnection heating, in which energy is released through many small magnetic reconnection events. Distinguishing the observational features of each mechanism is an extremely difficult task. On the other hand, observations have shown that energy release processes in the corona follow a power law distribution in frequency whose index may tell us whether small heating events contribute substantially to the heating or not. In this work we show a link between the power law index and the operating heating mechanism in a loop. We set up two coronal loop models: in the first model Alfvén waves created by footpoint shuffling nonlinearly convert to longitudinal modes which dissipate their energy through shocks; in the second model numerous heating events with nanoflare-like energies are input randomly along the loop, either distributed uniformly or concentrated at the footpoints. Both models are based on a 1.5-D MHD code. The obtained coronae differ in many aspects, for instance, in the simulated intensity profile that Hinode/XRT would observe. The intensity histograms display power law distributions whose indexes differ considerably. This number is found to be related to the distribution of the shocks along the loop. We thus test the observational signatures of the power law index as a diagnostic tool for the above heating mechanisms and the influence of the location of nanoflares.

Shoreline Change Analysis along the Udupi-Dakshina Kannada Coastal Stretch in Karnataka, West Coast of India using DSAS

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
N.A. Anjita ◽  
G.S. Dwarakish
Keyword(s):  
Remote Sensing ◽  
West Coast ◽  
Shoreline Change ◽  
Sediment Supply ◽  
Shoreline Changes ◽  
West Coast Of India ◽  
Erosion Rates ◽  
Wide Range ◽  
Cyclic Changes ◽  
Accretion And Erosion

Study of morphological variations and the effects of oceanographic processes such as erosion and accretion at different temporal scales are important to understand the nature of the coast and the cyclic changes occurring during different seasons. The Udupi-Dakshina Kannada coast along the west coast of India exhibits a wide range of changes depending on the interactions of tide and wave energy, sediment supply and more importantly human intervention. In view of this, the present work has been carried out to study the changes in shoreline changes along the Udupi-Dakshina Kannada coast over a period of 29 years from 1990 to 2019. Remote Sensing and GIS techniques have been used to demarcate shorelines and calculate the shoreline change rates. Overall accretion and erosion rates were found to be 1.28 m/year and 0.91 m/year respectively along the coast. Highest accretion and erosion rates of 12.57 m/year and 5.34 m/year was noticed along the Dakshina Kannada coast. The study also suggests that multi-dated satellite data along with statistical techniques can be effectively used for prediction of shoreline changes. Keywords: remote sensing, GIS, Dakshina Kannada coast, oceanography, shoreline.

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