scholarly journals Efficiency at optimal work from finite source and sink: A probabilistic perspective

2015 ◽  
Vol 40 (1) ◽  
pp. 1-12 ◽  
Author(s):  
Ramandeep S. Johal
Keyword(s):  
Prior Information ◽  
Present Formulation ◽  
Weighted Mean ◽  
Initial State ◽  
Standard Analysis ◽  
Valid Inference ◽  
Maximum Work ◽  
The Mean ◽  
Expected Values ◽  
The Given

AbstractWe revisit the classic thermodynamic problem of maximum work extraction from arbitrary-sized source of heat and sink, modelled as perfect gases. For a given initial state of the process, we assume ignorance of the final temperatures. We quantify the prior information about the process and assign a prior distribution to the unknown temperature(s). This requires that we also take into account the temperature values which are not regarded in standard analysis. In the present formulation, however, such values appear to be consistent with the given prior information and hence are included here in the inference. We derive estimates of the efficiency at optimal work from the expected values of the final temperatures, and show that these match with the exact expressions in the limit when any one of the systems is very large compared to the other. For other relative sizes of the source and the sink, a weighted mean is defined over the estimates from two valid inference procedures, that generalizes the procedure suggested earlier in [J. Phys. A: Math. Theor. 46 (2013), 365002]. The mean estimate for efficiency obtained in this way agrees with the results of the optimal performance quite accurately.

scholarly journals New Methodology for Computing the Aircraft’s Position Based on the PPP Method in GPS and GLONASS Systems

Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2525
Author(s):  
Kamil Krasuski ◽  
Damian Wierzbicki
Keyword(s):  
Linear Combination ◽  
Research Method ◽  
High Efficiency ◽  
Satellite System ◽  
Weighting Scheme ◽  
Measurement Technology ◽  
Dual Frequency ◽  
Weighted Mean ◽  
Mean Error ◽  
The Mean

In the field of air navigation, there is a constant pursuit for new navigation solutions for precise GNSS (Global Navigation Satellite System) positioning of aircraft. This study aims to present the results of research on the development of a new method for improving the performance of PPP (Precise Point Positioning) positioning in the GPS (Global Positioning System) and GLONASS (Globalnaja Nawigacionnaja Sputnikovaya Sistema) systems for air navigation. The research method is based on a linear combination of individual position solutions from the GPS and GLONASS systems. The paper shows a computational scheme based on the linear combination for geocentric XYZ coordinates of an aircraft. The algorithm of the new research method uses the weighted mean method to determine the resultant aircraft position. The research method was tested on GPS and GLONASS kinematic data from an airborne experiment carried out with a Seneca Piper PA34-200T aircraft at the Mielec airport. A dual-frequency dual-system GPS/GLONASS receiver was placed on-board the plane, which made it possible to record GNSS observations, which were then used to calculate the aircraft’s position in CSRS-PPP software. The calculated XYZ position coordinates from the CSRS-PPP software were then used in the weighted mean model’s developed optimization algorithm. The measurement weights are a function of the number of GPS and GLONASS satellites and the inverse of the mean error square. The obtained coordinates of aircraft from the research model were verified with the RTK-OTF solution. As a result of the research, the presented solution’s accuracy is better by 11–87% for the model with a weighting scheme as a function of the inverse of the mean error square. Moreover, using the XYZ position from the RTKLIB program, the research method’s accuracy increases from 45% to 82% for the model with a weighting scheme as a function of the inverse of the square of mean error. The developed method demonstrates high efficiency for improving the performance of GPS and GLONASS solutions for the PPP measurement technology in air navigation.

Fibre medullation in Blackface lambs and hoggs

1958 ◽  
Vol 51 (3) ◽  
pp. 257-264 ◽  
Author(s):  
J. M. Pilkington ◽  
A. F. Purser
Keyword(s):  
Average Degree ◽  
Fibre Types ◽  
Total Variance ◽  
Weighted Mean ◽  
The Mean

A method has been described of assessing the average degree of medullation in fleece samples. This method combines information about the various fibre types and the proportion of each present in the sample, by assigning 100 fibres to classes with scores 1–5 according to the degree of medullation. A weighted mean score was determined, ten times this mean being defined as the ‘medullation index’. The index has been used for 2 years on samples taken from 2-month-old lambs and 14-month-old hoggs of the Blackface breed. Drawings of fibre types showed that the internal and external diameters and their ratio all increase with the score.The mean medullation index for the 2-month-old lambs in the 2 years was 25·6 and 24·8. The effects of sex and type of birth of lamb and age of dam were assessed by fitting constants, but their contribution to the total variance was very small. The regression of medullation on age of lamb when sampled was −0·11 units per day in both years, and was highly significant. Possible explanations for this decline of medullation are discussed.The mean medullation index for 14-month-old hoggs was 16·1 in both years. Estimate of correlation between lamb and hogg for the 2 years were + 0·45 and + 0·33. It is probable that variation in medullation within the fleece and in fibre shedding account for these low values.

scholarly journals Implementation of a provincial acute stroke pathway and its impact on access to advanced stroke care in Saskatchewan

2021 ◽  
Vol 10 (3) ◽  
pp. e001214
Author(s):  
Jessalyn K Holodinsky ◽  
Vivian N Onaemo ◽  
Ruth Whelan ◽  
Gary Hunter ◽  
Brett R Graham ◽  
...  
Keyword(s):  
Acute Stroke ◽  
Control Charts ◽  
Systems Of Care ◽  
Stroke Care ◽  
High Variability ◽  
Weighted Mean ◽  
Improvement Project ◽  
Outcome Severity ◽  
The Mean ◽  
Over Time

BackgroundFor ischaemic stroke, outcome severity is heavily time dependent. Systems of care need to be in place to ensure that patients with stroke are treated quickly and appropriately across entire health regions. Prior to this study, the province of Saskatchewan, Canada did not have a provincial stroke strategy in place.MethodsA quality improvement project was undertaken to create and evaluate a provincial stroke strategy. The Saskatchewan Acute Stroke Pathway was created using a multidisciplinary team of experts, piloted at five stroke centres and then implemented provincially. The number of stroke alerts, door-to-imaging, door-to-needle, door-to-groin puncture times and treatment rates were collected at all centres. Improvements over time were analysed using run charts and individuals control charts.ResultsThe number of stroke alerts province-wide trended upwards in the last 6 months of the study. There were no clear trends or shifts in the proportion of stroke alerts treated with alteplase or endovascular therapy. Across the province, the weighted mean door-to-imaging time decreased from 21 to 15 min, the weighted mean door-to-needle time decreased from 62 to 47 min and the mean door-to-groin puncture time decreased from 83 to 70 min. There was high variability in the degree of improvement from centre to centre.ConclusionsThe implementation of a province wide acute stroke pathway has led to improvement in stroke care on a provincial basis. Further work addressing intercentre variability is ongoing.

Interlaced Attitude Estimation for Spacecraft Using Vector Observations

2021 ◽  
Vol 01 (03) ◽  
Author(s):  
Lubin Chang
Keyword(s):  
Prior Information ◽  
State Of The Art ◽  
Estimation Method ◽  
Attitude Estimation ◽  
The Body ◽  
Body Frame ◽  
Initial Value ◽  
Initial State ◽  
Initial Errors ◽  
Initial Attitude

This paper proposes an interlaced attitude estimation method for spacecraft using vector observations, which can simultaneously estimate the constant attitude at the very start and the attitude of the body frame relative to its initial state. The arbitrary initial attitude, described by constant attitude at the very start, is determined using quaternion estimator which requires no prior information. The multiplicative extended Kalman filter (EKF) is competent for estimating the attitude of the body frame relative to its initial state since the initial value of this attitude is exactly known. The simulation results show that the proposed algorithms could achieve better performance compared with the state-of-the-art algorithms even with extreme large initial errors. Meanwhile, the computational burden is also much less than that of the advanced nonlinear attitude estimators.

Characterizing persistence and pause dynamical behaviors in biological systems

2021 ◽  
pp. 2150133
Author(s):  
Nicholas Mwilu Mutothya ◽  
Yong Xu
Keyword(s):  
Phase Transition ◽  
Dynamical Behavior ◽  
Nonlinear Function ◽  
Switching Rate ◽  
Initial State ◽  
Average Speed ◽  
Mean Squared Displacement ◽  
The Mean ◽  
Short Times ◽  
Direction Switching

This paper analyzed motion that randomly switches between the persistent motion runs and pause periods. A two-state continuous-time Markov chain is used to model the motion, which led to a system with coupled differential equations. Using a combined Fourier–Laplace transform, an analytical expression for calculating the mean-squared displacement is derived. The overall motion is investigated and identified from the obtained mean-squared displacement. The mean-squared displacement is a nonlinear function in time that is dependent on the phase transition rate, the direction switching rate, the average speed, and the initial state. It decays and grows with increasing the direction switching and average speed, respectively. The effective diffusivity descents exponentially in short times and remains constant in long times. The waiting time in each phase decayed exponentially. The probability density function for the position of a particle at a given time tends to be Gaussian in long times. The motion can be interpreted as a super-diffusion in short times and a standard diffusion in long times with a diffusion coefficient dependent on the phase transition rates, the direction switching rate and the average speed. Persistence influences the dynamical behavior for short times while for long times diffusive behavior is exhibited.

scholarly journals Performance and Statistical Analysis of Stream ciphers in GSM Communications

2020 ◽  
Vol 16 (1) ◽  
pp. 11-18 ◽  
Author(s):  
Nagendar Yerukala ◽  
V Kamakshi Prasad ◽  
Allam Apparao
Keyword(s):  
Statistical Analysis ◽  
Stream Cipher ◽  
Statistical Tests ◽  
Stream Ciphers ◽  
Test Suite ◽  
Secret Key ◽  
Initial State ◽  
Detailed Statistical Analysis ◽  
Almost All ◽  
The Given

For a stream cipher to be secure, the keystream generated by it should be uniformly random with parameter 1/2.Statistical tests check whether the given sequence follow a certain probability distribution. In this paper, we perform a detailed statistical analysis of various stream ciphers used in GSM 2G,3G, 4G and 5G communications. The sequences output by these ciphers are checked for randomness using the statistical tests defined by the NIST Test Suite. It should also be not possible to derive any information about secret key and the initial state ofthe cipher from the keystream. Therefore, additional statisticaltests based on properties like Correlation between Keystreamand Key, and Correlation between Keystream and IV are also performed. Performance analysis of the ciphers also has been done and the results tabulated. Almost all the ciphers pass thetests in the NIST test suite with 99% confidence level. For A5/3stream cipher, the correlation between the keystream and key is high and correlation between the keystream and IV is low when compared to other ciphers in the A5 family.

scholarly journals The Parallaxes of U Gem Variables

1979 ◽  
Vol 53 ◽  
pp. 494-494
Author(s):  
Karl W. Kamper
Keyword(s):  
Confidence Level ◽  
Absolute Magnitude ◽  
Weighted Mean ◽  
Quiescent Phase ◽  
A Value ◽  
The Mean ◽  
The Absolute ◽  
Absolute Magnitudes

An Allegheny parallax series of SS Cyg, consisting of 52 exposures obtained on 15 nights, was recently measured on the PDS microphotometer at the David Dunlap Observatory, and a value of (m.e.) derived for the absolute parallax. This is close to the mean of the two previous discordant measures for this star given in the table below. The weighted mean of the three determinations implies that the absolute magnitude, at quiescent phase, of the star is between 7.0 and 9.0 formally at a 90% confidence level. Recent parallax determinations made at Lick by Vasilevskls et al. (1975) for three other stars, listed below along with the Mt. Wilson value for U Gem, imply even fainter absolute magnitudes.

scholarly journals Numerical Modeling of Force-Stiffness Response of Cross-Linked Actin Networks Using Tensegrity Systems

2015 ◽  
Vol 2015 ◽  
pp. 1-6
Author(s):  
Xian Xu ◽  
Yafeng Wang ◽  
Yaozhi Luo
Keyword(s):  
Three Dimensional ◽  
Structural Response ◽  
Postbuckling Behavior ◽  
Actin Networks ◽  
Tensegrity Structure ◽  
Tensegrity Systems ◽  
Order Polynomial ◽  
The Mean ◽  
The Given ◽  
Tensegrity Model

A three-dimensional tensegrity structure is used as a computational model for cross-linked actin networks. The postbuckling behavior of the members under compression is considered and the constitutive relation of the postbuckling members is modeled as a second-order polynomial. A numerical scheme incorporating the equivalent constitution of the postbuckling members is used to predict the structural response of the tensegrity model under compression loads. The numerical simulation shows that the stiffness of the tensegrity structure nonlinearly increases before member buckling and abruptly decreases to a lower level as soon as members buckle. This result qualitatively mimics the experimentally observed stiffness to compression stress response of cross-linked actin networks. In order to take member length variety into account, a large number of simulations with the length of buckling members varying in the given range are also carried out. It is found that the mean response of the simulations using different buckling member length exhibits more resemblance to the experimental observation.

scholarly journals Optimizing the Pairs-Trading Strategy Using Deep Reinforcement Learning with Trading and Stop-Loss Boundaries

Complexity ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-20 ◽  
Author(s):  
Taewook Kim ◽  
Ha Young Kim
Keyword(s):  
Reinforcement Learning ◽  
Trading Strategy ◽  
Trading Strategies ◽  
Cointegration Test ◽  
Optimum Level ◽  
Pairs Trading ◽  
Proposed Model ◽  
The Mean ◽  
Stop Loss ◽  
The Given

Many researchers have tried to optimize pairs trading as the numbers of opportunities for arbitrage profit have gradually decreased. Pairs trading is a market-neutral strategy; it profits if the given condition is satisfied within a given trading window, and if not, there is a risk of loss. In this study, we propose an optimized pairs-trading strategy using deep reinforcement learning—particularly with the deep Q-network—utilizing various trading and stop-loss boundaries. More specifically, if spreads hit trading thresholds and reverse to the mean, the agent receives a positive reward. However, if spreads hit stop-loss thresholds or fail to reverse to the mean after hitting the trading thresholds, the agent receives a negative reward. The agent is trained to select the optimum level of discretized trading and stop-loss boundaries given a spread to maximize the expected sum of discounted future profits. Pairs are selected from stocks on the S&P 500 Index using a cointegration test. We compared our proposed method with traditional pairs-trading strategies which use constant trading and stop-loss boundaries. We find that our proposed model is trained well and outperforms traditional pairs-trading strategies.

Estimate of mean tissue O2 consumption at onset of exercise in males

1987 ◽  
Vol 63 (4) ◽  
pp. 1578-1585 ◽  
Author(s):  
M. D. Inman ◽  
R. L. Hughson ◽  
K. H. Weisiger ◽  
G. D. Swanson
Keyword(s):  
Mathematical Model ◽  
Cardiac Output ◽  
Time Delay ◽  
Impedance Cardiography ◽  
Work Rate ◽  
Rate Of Change ◽  
O2 Consumption ◽  
Weighted Mean ◽  
Mean Response Time ◽  
The Mean

A mathematical model has been developed that permitted the calculation of the flow-weighted mean tissue O2 consumption (VO2T) at the onset of a step increase in work rate. From breath-by-breath measurements of alveolar O2 consumption (VO2A) and cardiac output (Q) by impedance cardiography and assumptions about the site of depletion of O2 stores, the rate of change in O2 stores (VO2s) was determined. The sum of VO2A + VO2s = VO2T. Six very fit males performed six repetitions of each of two step increases in work rate. STlo was a transition from rest to 100-W cycling; SThi was a transition from 100- to 200-W cycling. For each work rate transition, the responses of VO2A and Q were averaged over the six repetitions of each subject and the model was solved to yield VO2T. The responses of VO2A, VO2T, and Q after the increase in work rate were fit with a monoexponential function. This function included a time constant and time delay, the sum of which gave the mean response time (MRT). In the STlo test, the MRT of VO2A (24.9 +/- 1.1 s, mean +/- SE) was longer than that of VO2T (15.3 +/- 1.3 s) and of Q (16.5 +/- 6.5 s) (P less than 0.05). The MRT of VO2T and Q did not differ significantly. Also for SThi, the MRT of VO2A (34.4 +/- 3.3 s) was significantly longer than that of VO2T (30.0 +/- 3.4 s) (P less than 0.05). The MRT of VO2T and Q (30.3 +/- 5.5 s) were not significantly different at this work rate either.(ABSTRACT TRUNCATED AT 250 WORDS)

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