A common method for Controlling a group of parallel converters in decentralized Control strategy structure in an island microgrid, the use is the droop-down characteristics of frequency ω-P and voltage E-Q. However, the problem with using this method is that the reactive power is not properly distributed (in proportion to the capacity of the micronutrients) between the micronutrients, which may lead to overload in the converters. Microgrids may also suffer from dynamic stability problems such as power fluctuations, which can be increased by switching between active and reactive power Control. To avoid this problem, the X / R ratio of transmission lines is an important parameter that should be carefully considered in the design of micronutrient Controllers. By linearizing and simplifying conditions, the Control system conversion function model becomes a single input-single output system, which is efficient enough to show the relationship between Control parameters such as slope of droop characteristics and derivative sentences, virtual impedance, and voltage Controllers. Using this model, stability conditions for different parameters are analyzed. Also, to improve power distribution stability, common droop strategies are modified by adjusting the slope as well as adding nonlinear sentence sections. This approach reduces the coupling between active and reactive power Control and reduces the dependence of power distribution on grid parameters such as the X / R ratio. To evaluate the reliability of the proposed model, the simulation results in a sample island microgrid in MATLAB software are presented.

Heterogeneous networks, including macrocell and femtocell, cause to increase network capacity. Also, they improve quality of offers services to users in cellular networks. Common subchannel Allocation among different tier users, make cross-tier interference among users. Since macrocell users have priority to femtocell ones, presence of femtocell users should not prevent macrocell users to access minimum quality-of-service. In this paper, a power Control and subchannel Allocation scheme in downlink transmission an orthogonal frequency division multiple access (OFDMA) based two tier of macrocell and femtocell is proposed, aiming the maximization of femtocell users total data rate, in which the minimum QOS for all macrocell users and femtocell delay-sensitive users is observed. In macrocell tier, two different problems are considered. The first problem aim to maximizing the total threshold of tolerable cross-tier interference for macrocell users and the second problem’s goal is minimizing the macrocell’s total transmission power. For the femtocell tier, maximizing the users total data rate is the objective. Hungrian method, an assignment optimization method, is used for solving the first problem in macrocell tier. Moreover, in order to solve the second problem a heuristic method for subchannel Allocation is proposed and dual Lagrange method is used for power Control. In addition, in order to solve the problem for femtocell tier, a heuristic method is used for subchannel Allocation. Subsequently, a dual Lagrange method which is one of the convex optimization problem solver is used, so that we can Control the power. Finally, an extend simulations are performed to validate the performance of the proposed method.

This study investigates the process of budget Allocation to provinces of Iran based on two set of factors of 1- major macro provincial indicators and 2-oil price volatility based on stochastic differential equations and stochastic optimal Control framework during the period of 2003 to 2014. In this regard, with calculation of optimal share of provinces in total country budget based on macro indicators data for year 2011, the effect of stochastic oil price on dynamic budget Allocation is studied. The dynamic analysis of oil price during 2003 to 2014 indicates a volatile trend with jumps in oil price time series in some sub-periods. Accordingly, different models of stochastic differential equations and stochastic optimal Control for modeling oil price and petroleum budgets Allocation in different years are proposed. The results show that the share of the provincial budget depends on the parameters that determine the behavior of the oil price time series. So that, with an increased average growth rate of oil prices, the provincial budget share increases over time. In addition, an increase in volatility of oil prices and acceleration in the velocity of oil price mean-reversion, reduce the optimal share of provincial oil budgets over time. Also, based on the results of the simulation model for provincial data in year 2011, the optimal share of provincial oil budgets has dynamic and stochastic behavior and it is formed based on the behavior of oil price time series.

The main objective of this article is to apply the Control Allocation approach for the landing phase of the F/A-18 aircraft. For this purpose, the non-linear three-degree-of-freedom model of the aircraft is used, and the intelligent Control Allocation approach, based on fuzzy logic, is utilized to design the longitudinal flight Control system. The actuators involved in the aircraft landing process are the elevator angle and the thrust vector Control angle of the aircraft engine. By allocating Control signals between the two mentioned actuators, the plane starts the process of lowering the height and finally reaches the ground level. To improve the efficiency of the fuzzy Controller, reduce the Control effort and increase the accuracy and quality of the landing, the genetic algorithm based on the NSGA-II method is used and the variables of the fuzzy Controller are modified. The results obtained from the simulation show that the proposed Control Allocation approach has a high ability to Control and stabilize the aircraft in the landing process. Also, the output variables converge to a desired value and the aircraft completes the landing process with proper accuracy and low Control effort.