Scintillation due to atmospheric turbulence on optical GEO and MEO satellite links: Time series synthesizer for system level simulations

2020 ◽  
Author(s):  
Nikolaos K. Lyras ◽  
Charilaos I. Kourogiorgas ◽  
Athanasios D. Panagopoulos
Keyword(s):  
Time Series ◽  
Atmospheric Turbulence ◽  
System Level ◽  
Satellite Links ◽  
System Level Simulations

Prediction of Atmospheric Turbulence Characteristics for Surface Boundary Layer using Empirical Spectral Methods

2020 ◽  
Author(s):  
Yagya Dutta Dwivedi ◽  
Vasishta Bhargava Nukala ◽  
Satya Prasad Maddula ◽  
Kiran Nair
Keyword(s):  
Boundary Layer ◽  
Time Series ◽  
Surface Roughness ◽  
Wind Speed ◽  
Atmospheric Turbulence ◽  
Surface Boundary ◽  
Low Frequencies ◽  
Surface Boundary Layer ◽  
Power Spectral ◽  
Mean Wind Speed

Abstract Atmospheric turbulence is an unsteady phenomenon found in nature and plays significance role in predicting natural events and life prediction of structures. In this work, turbulence in surface boundary layer has been studied through empirical methods. Computer simulation of Von Karman, Kaimal methods were evaluated for different surface roughness and for low (1%), medium (10%) and high (50%) turbulence intensities. Instantaneous values of one minute time series for longitudinal turbulent wind at mean wind speed of 12 m/s using both spectra showed strong correlation in validation trends. Influence of integral length scales on turbulence kinetic energy production at different heights is illustrated. Time series for mean wind speed of 12 m/s with surface roughness value of 0.05 m have shown that variance for longitudinal, lateral and vertical velocity components were different and found to be anisotropic. Wind speed power spectral density from Davenport and Simiu profiles have also been calculated at surface roughness of 0.05 m and compared with k−1 and k−3 slopes for Kolmogorov k−5/3 law in inertial sub-range and k−7 in viscous dissipation range. At high frequencies, logarithmic slope of Kolmogorov −5/3rd law agreed well with Davenport, Harris, Simiu and Solari spectra than at low frequencies.

scholarly journals Using the WHO Safe Childbirth Checklist to Improve Essential Care Delivery as Part of the District -Wide Maternal and Newborn Health Quality Improvement Initiative, a Time Series Study

2020 ◽  
Author(s):  
Befikadu Bitewulign ◽  
Dereje Abdissa ◽  
Zewdie Mulissa ◽  
Abiyou Kiflie ◽  
Mehiret Abate ◽  
...  
Keyword(s):  
Time Series ◽  
Quality Improvement ◽  
Newborn Health ◽  
System Level ◽  
Maternal And Newborn Health ◽  
Safe Childbirth Checklist ◽  
Safe Childbirth ◽  
Over Time ◽  
Maternal And Newborn

Abstract Background: Care bundles are a set of three to five evidence-informed practices which, when performed collectively and reliably, may improve health system performance and patient care. To date, many studies conducted to improve the quality of essential birth care practices (EBPs) have focused primarily on provider- level and have fallen short of the predicted impact on care quality, indicating that a systems approach is needed to improve the delivery of reliable quality care. This study evaluates the effectiveness of integrating the use of the World Health Organization Safe Childbirth Checklist (WHO-SCC) into a district-wide system improvement collaborative program designed to improve and sustain the delivery of EBPs as measured by "clinical bundle" adherence over-time.Methods: The WHO-SCC was introduced in the context of a district-wide Maternal and Newborn Health (MNH) collaborative quality of care improvement program in four agrarian Ethiopia regions. Three "clinical bundles" were created from the WHO-SCC: On Admission, Before Pushing, and Soon After Birth bundles. The outcome of each bundle was measured using all- or- none adherence. Adherence was assessed monthly by reviewing charts of live births.A time-series analysis was employed to assess the effectiveness of system-level interventions on clinical bundle adherence. STATA version 13.1 was used to analyze the trend of each bundle adherence overtime. Autocorrelation was checked to assess if the assumption of independence in observations collected overtime was valid. Prais-Winsten was used to minimize the effect of autocorrelation.Findings: Quality improvement interventions targeting the three clinical bundles resulted in improved adherence over time across the four regions. In Tigray region, adherence to “On Admission” bundle was increased monthly on average by B =1.39 (95% CI; 0.47 - 2.32; P<0.005).Similarly, adherence to the “Before Pushing” bundle in Southern Nations, Nationalities and People’s (SNNP) region increased monthly on average by B = 2.3 (95% CI; 0.89 - 3.74; P<0.005). Conclusion: Use of the WHO-SCC paired with a system-wide quality improvement approach improved and sustained quality of EBPs delivery. Further studies should be conducted to evaluate the impact on patient-level outcomes.

Design, modelling and system level simulations of DRIE-based MEMS differential capacitive accelerometer

2019 ◽  
Vol 25 (9) ◽  
pp. 3521-3532 ◽  
Author(s):  
R. Mukhiya ◽  
P. Agarwal ◽  
S. Badjatya ◽  
M. Garg ◽  
P. Gaikwad ◽  
...  
Keyword(s):  
System Level ◽  
Capacitive Accelerometer ◽  
System Level Simulations

Integration of High Speed Train Channel Measurements in System Level Simulations

2019 ◽  
Author(s):  
Martin Klaus Muller ◽  
Tomas Dominguez-Bolano ◽  
Jose A. Garcia-Naya ◽  
Luis Castedo ◽  
Markus Rupp
Keyword(s):  
High Speed ◽  
System Level ◽  
Channel Measurements ◽  
High Speed Train ◽  
System Level Simulations
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