scholarly journals Environmental degradation and indeterminacy of equilibrium selection

2021 ◽  
Vol 0 (0) ◽  
pp. 0
Author(s):  
Angelo Antoci ◽  
Marcello Galeotti ◽  
Mauro Sodini
Keyword(s):  
Dynamic System ◽  
Environmental Degradation ◽  
Optimization Problem ◽  
Global Analysis ◽  
Control Variable ◽  
Equilibrium Selection ◽  
State Variables ◽  
Initial Values ◽  
Intertemporal Optimization ◽  
Environmental Good

<p style='text-indent:20px;'>This paper analyzes an intertemporal optimization problem in which agents derive utility from three goods: leisure, a public environmental good and the consumption of a produced good. The global analysis of the dynamic system generated by the optimization problem shows that global indeterminacy may arise: given the initial values of the state variables, the economy may converge to different steady states, by choosing different initial values of the control variable.</p>

Reentry Trajectory Optimization and Simulation of Hypersonic Vehicle with Maximum Cross Range Based on GPM

2014 ◽  
Vol 635-637 ◽  
pp. 1431-1437
Author(s):  
Wu Jun Huo ◽  
Xu Liu ◽  
Li Wang ◽  
Chao Song
Keyword(s):  
Trajectory Optimization ◽  
Optimization Problem ◽  
Control Variable ◽  
Pseudospectral Method ◽  
Hypersonic Vehicle ◽  
State Variables ◽  
Hypersonic Aircraft ◽  
Gauss Pseudospectral Method ◽  
Reentry Trajectory ◽  
Reentry Trajectory Optimization

Abstract：The application of Gauss pseudospectral method (GPM) to hypersonic aircraft reentry trajectory optimization problem with maximum cross range was introduced. The Gauss pseudospectral method was used to solve the reentry trajectory of the hypersonic vehicle with the maximum cross range. Firstly, the model of hypersonic aircraft reentry trajectory optimization control problem was established. Taking no account of course constraint, the maximum cross range was chosen as optimal performance index, and angle of attack and bank was chosen as control variable. Terminal state was constrained by position and velocity. Then GPM was applied to change trajectory optimization problem into nonlinear programming problem (NLP), and the state variables and control variables were selected as optimal parameters at all Gauss nodes. At last, optimal reentry trajectory was solved by solving the NLP with the help of SNOPT. The simulation results indicate that GPM does not need to estimate the initial cost variable, and it is not sensitive to the initial states and effective to solve trajectory optimization problem.

Is food production vulnerable to environmental degradation? A global analysis

2021 ◽  
Author(s):  
Suet-Ling Ching ◽  
Kwang-Jing Yii ◽  
Cheong-Fatt Ng ◽  
Chee-Keong Choong ◽  
Lin-Sea Lau
Keyword(s):  
Environmental Degradation ◽  
Food Production ◽  
Global Analysis

scholarly journals All-Sky Radiance Assimilation of ATMS in HWRF: A Demonstration Study

2018 ◽  
Vol 147 (1) ◽  
pp. 85-106 ◽  
Author(s):  
Ting-Chi Wu ◽  
Milija Zupanski ◽  
Lewis D. Grasso ◽  
Christian D. Kummerow ◽  
Sid-Ahmed Boukabara
Keyword(s):  
Single Case ◽  
Control Variable ◽  
Data Availability ◽  
Advanced Technology ◽  
Radiative Transfer Model ◽  
Transfer Model ◽  
State Variables ◽  
Initial State ◽  
Clear Sky ◽  
Analysis System

Abstract Satellite all-sky radiances from the Advanced Technology Microwave Sounder (ATMS) are assimilated into the Hurricane Weather Research and Forecasting (HWRF) Model using the hybrid Gridpoint Statistical Interpolation analysis system (GSI). To extend the all-sky capability recently developed for global applications to HWRF, some modifications in HWRF and GSI are facilitated. In particular, total condensate is added as a control variable, and six distinct hydrometeor habits are added as state variables in hybrid GSI within HWRF. That is, clear-sky together with cloudy and precipitation-affected satellite pixels are assimilated using the Community Radiative Transfer Model (CRTM) as a forward operator that includes hydrometeor information and Jacobians with respect to hydrometeor variables. A single case study with the 2014 Atlantic storm Hurricane Cristobal is used to demonstrate the methodology of extending the global all-sky capability to HWRF due to ATMS data availability. Two data assimilation experiments are carried out. One experiment uses the operational configuration and assimilates ATMS radiances under the clear-sky condition, and the other experiment uses the modified HWRF system and assimilates ATMS radiances under the all-sky condition with the inclusion of total condensate update and cycling. Observed and synthetic Geostationary Operational Environmental Satellite (GOES)-13 data along with Global Precipitation Measurement Mission (GPM) Microwave Imager (GMI) data from the two experiments are used to show that the experiment with all-sky ATMS radiances assimilation has cloud signatures that are supported by observations. In contrast, there is lack of clouds in the initial state that led to a noticeable lag of cloud development in the experiment that assimilates clear-sky radiances.

Numerical Method for Power Losses Minimization of Vector-Controlled Induction Motor

2015 ◽  
Vol 6 (3) ◽  
pp. 486 ◽  
Author(s):  
Alex Borisevich
Keyword(s):  
Induction Motor ◽  
Optimization Problem ◽  
Search Algorithm ◽  
Control Variable ◽  
Control Input ◽  
Power Losses ◽  
Ohmic Losses ◽  
Operation Control ◽  
Dynamic Time ◽  
Motor Operation

<p>The paper devoted to energy efficiency maximizing problem of the induction motor under part-load conditions. The problem is formulated as the minimization of ohmic losses power as a function from flux-producing current in field-oriented motor operation. Control input precompensation which transforms the dynamic time-varying optimization problem to stationary one is introduced. Adjustment rule for control variable is proposed which speeds-up the method convergence in comparison with linear variation of input. Finally a new continuous-time search algorithm for solving the problem of minimizing power consumption was given. The statements on method behavior were formulated and convergence to local minimum was proved. The method verified in simulation and in hardware experimental setup.</p>

scholarly journals Latent Heat Flux Sensitivity to Sea Surface Temperature: Regional Perspectives

2017 ◽  
Vol 30 (1) ◽  
pp. 129-143 ◽  
Author(s):  
B. Praveen Kumar ◽  
Meghan F. Cronin ◽  
Sudheer Joseph ◽  
M. Ravichandran ◽  
N. Sureshkumar
Keyword(s):  
Heat Flux ◽  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Latent Heat ◽  
Latent Heat Flux ◽  
Global Analysis ◽  
Surface Wind ◽  
Sea Surface ◽  
State Variables ◽  
Monsoon Period

A global analysis of latent heat flux (LHF) sensitivity to sea surface temperature (SST) is performed, with focus on the tropics and the north Indian Ocean (NIO). Sensitivity of LHF state variables (surface wind speed Ws and vertical humidity gradients Δq) to SST give rise to mutually interacting dynamical (Ws driven) and thermodynamical (Δq driven) coupled feedbacks. Generally, LHF sensitivity to SST is pronounced over tropics where SST increase causes Ws (Δq) changes, resulting in a maximum decrease (increase) of LHF by ~15 W m−2 (°C)−1. But the Bay of Bengal (BoB) and north Arabian Sea (NAS) remain an exception that is opposite to the global feedback relationship. This uniqueness is attributed to strong seasonality in monsoon Ws and Δq variations, which brings in warm (cold) continental air mass into the BoB and NAS during summer (winter), producing a large seasonal cycle in air–sea temperature difference ΔT (and hence in Δq). In other tropical oceans, surface air is mostly of marine origin and blows from colder to warmer waters, resulting in a constant ΔT ~ 1°C throughout the year, and hence a constant Δq. Thus, unlike other basins, when the BoB and NAS are warming, air temperature warms faster than SST. The resultant decrease in ΔT and Δq contributes to decrease the LHF with increased SST, contrary to other basins. This analysis suggests that, in the NIO, LHF variability is largely controlled by thermodynamic processes, which peak during the monsoon period. These observed LHF sensitivities are then used to speculate how the surface energetics and coupled feedbacks may change in a warmer world.

scholarly journals Noise Assisted Image Encryption and Decryption using 2-D Chaotic System

2021 ◽  
Author(s):  
Namrata Biswas ◽  
I. Raja Mohamed
Keyword(s):  
Image Encryption ◽  
Chaotic System ◽  
Color Image ◽  
Image Transmission ◽  
Noise Signal ◽  
State Variables ◽  
Initial Values ◽  
Xor Operation ◽  
Encryption And Decryption ◽  
Information Image

Abstract In this paper, a new two-dimensional (2-D) chaos-based color image encryption and decryption scheme is proposed in which the noise signal is selected randomly to set the initial values for a chaotic system which also enhances the security of the system. The 256-bit hash value of noise is transformed into one-time initial values for the state variables of this proposed chaotic system. XOR operation is further carried out to diffuse the pixels. Finally, statistical and security analyses are performed for understanding the effectiveness of the proposed system. Experimental results confirm that the proposed chaos-based cryptosystem is efficient and suitable for information (image) transmission in a highly secured way.

scholarly journals Autonomic Properties in Traffic Control

2013 ◽  
Vol 13 (4) ◽  
pp. 18-32
Author(s):  
Krasimira Stoilova ◽  
Todor Stoilov ◽  
Konstantin Nikolov
Keyword(s):  
Traffic Control ◽  
Optimization Problem ◽  
Optimization Problems ◽  
Transportation Network ◽  
Control Variable ◽  
Solution Space ◽  
Transportation Systems ◽  
Multilevel Approach ◽  
Control Approach ◽  
Traffic Control System

Abstract The operation of a complex system like a transportation network is considered with respect to the opportunities to identify the application of autonomic properties. The autonomic features of self-properties are analyzed. A multilevel approach is suggested for the formalization of the transport operation. The integration of relevant optimization problems is also considered in the framework of a multilevel, hierarchical scheme of control. The application of bi-level formalism in the transportation systems gives quantitative assessment of the control processes in the traffic control system. The multilevel approach allows the increase of the solution space of a complex optimization problem with an additional traffic control variable, which in the classical optimal formalization participates with fixed parameters in the optimization problem. The benefit of the multilevel control approach is tested in a real network of crossroad sections.

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