scholarly journals Approach to optimizing charging infrastructure of autonomous trolleybuses for urban routes

Informatics ◽  
2021 ◽  
Vol 18 (4) ◽  
pp. 79-95
Author(s):  
М. Ya. Kovalyov ◽  
B. M. Rozin ◽  
I. A. Shaternik
Keyword(s):  
Mathematical Programming ◽  
Service Life ◽  
Objective Function ◽  
Heuristic Method ◽  
Cost Effective ◽  
Linear Constraints ◽  
Mathematical Programming Problem ◽  
Electric Transport ◽  
Charging Infrastructure ◽  
Charging Stations

P u r p o s e s.  When designing a system of urban electric transport that charges while driving, including autonomous trolleybuses with batteries of increased capacity, it is important to optimize the charging infrastructure for a fleet of such vehicles. The charging infrastructure of the dedicated routes consists of overhead wire sections along the routes and stationary charging stations of a given type at the terminal stops of the routes. It is designed to ensure the movement of trolleybuses and restore the charge of their batteries, consumed in the sections of autonomous running.The aim of the study is to create models and methods for developing cost-effective solutions for charging infrastructure, ensuring the functioning of the autonomous trolleybus fleet, respecting a number of specific conditions. Conditions include ensuring a specified range of autonomous trolleybus running at a given rate of energy consumption on routes, a guaranteed service life of their batteries, as well as preventing the discharge of batteries below a critical level under various operating modes during their service life.M e t ho d s. Methods of set theory, graph theory and linear approximation are used.Re s u l t s. A mathematical model has been developed for the optimization problem of the charging infrastructure of the autonomous trolleybus fleet. The total reduced annual costs for the charging infrastructure are selected as the objective function. The model is formulated as a mathematical programming problem with a quadratic objective function and linear constraints.Co n c l u s i o n. To solve the formulated problem of mathematical programming, standard solvers such as IBM ILOG CPLEX can be used, as well as, taking into account its computational complexity, the heuristic method of "swarm of particles".  The solution to the problem is to select the configuration of the location of the overhead wire sections on the routes and the durations of charging the trolleybuses at the terminal stops, which determine the corresponding number of stationary charging stations at these stops.

scholarly journals Research of New Criteria for Detecting First-order Residuals Autocorrelation in Regression Models

2018 ◽  
pp. 13-25
Author(s):  
M. P. Bazilevsky
Keyword(s):  
Mathematical Programming ◽  
Regression Model ◽  
Least Squares ◽  
Regression Models ◽  
Linear Constraints ◽  
Mathematical Programming Problem ◽  
First Order ◽  
Watson Statistic ◽  
Auto Regression ◽  
New Criteria

When estimating regression models using the least squares method, one of its prerequisites is the lack of autocorrelation in the regression residuals. The presence of autocorrelation in the residuals makes the least-squares regression estimates to be ineffective, and the standard errors of these estimates to be untenable. Quantitatively, autocorrelation in the residuals of the regression model has traditionally been estimated using the Durbin-Watson statistic, which is the ratio of the sum of the squares of differences of consecutive residual values to the sum of squares of the residuals. Unfortunately, such an analytical form of the Durbin-Watson statistic does not allow it to be integrated, as linear constraints, into the problem of selecting informative regressors, which is, in fact, a mathematical programming problem in the regression model. The task of selecting informative regressors is to extract from the given number of possible regressors a given number of variables based on a certain quality criterion.The aim of the paper is to develop and study new criteria for detecting first-order autocorrelation in the residuals in regression models that can later be integrated into the problem of selecting informative regressors in the form of linear constraints. To do this, the paper proposes modular autocorrelation statistic for which, using the Gretl package, the ranges of their possible values and limit values were first determined experimentally, depending on the value of the selective coefficient of auto-regression. Then the results obtained were proved by model experiments using the Monte Carlo method. The disadvantage of the proposed modular statistic of adequacy is that their dependencies on the selective coefficient of auto-regression are not even functions. For this, double modular autocorrelation criteria are proposed, which, using special methods, can be used as linear constraints in mathematical programming problems to select informative regressors in regression models.

scholarly journals Study of design features of mobile charging units for electric transport for development of sketch design documentation

2022 ◽  
Vol 23 (5) ◽  
pp. 100-114
Author(s):  
A. R. Safin ◽  
I. V. Ivshin ◽  
A. N. Tsvetkov ◽  
T. I. Petrov ◽  
V. R. Basenko ◽  
...  
Keyword(s):  
Electric Vehicles ◽  
Small Range ◽  
Electric Transport ◽  
Design Features ◽  
Power Sources ◽  
Charging Infrastructure ◽  
Factors Influencing ◽  
The World ◽  
Design Documentation ◽  
Charging Stations

THE PURPOSE. Charging infrastructure is one of the factors influencing the transition to electric vehicles, as the electric vehicles in operation are characterized by a small range and a long battery charge period. Today, the development of the charging infrastructure depends only on the networks of stationary charging stations, which also have disadvantages (high cost, lack of mobility, etc.). Therefore, the purpose of this work is to study the design features of mobile electric vehicle charge units (MCSEU) for the development of draft design documentation for the creation of a new MCSEU project. This issue includes the study of the world market of manufacturers of modern mobile chargers, the study of technical and operational features that are today presented to modern energy storage and storage systems.MATERIALS. The authors of the article processed and analyzed data on the current state of the charging infrastructure in Russia and the world, based on materials from Russian and foreign authors, as well as information on the development strategy of the electric transport industry in Russia and the world, in particular, data from Madison Gas and Electric.RESULTS. The obtained analytical results are one of the aspects that will be taken into account when developing mobile charging devices for electric vehicles. This mobile charger technology significantly expands the possibilities of using electric vehicles, in particular electric vehicles, and also solves various problems of the fuel and energy complex associated with autonomous power sources and distributed generation systems.CONCLUSION. The charging infrastructure is one of the factors influencing the transition to electric vehicles, as the electric vehicles in operation are characterized by a small range and a long period of charging the traction battery. However, this process will be long and in the near future networks of charging stations will be created, including mobile charging units for electric vehicles.

scholarly journals Determination of the Optimal Values of the Parameters of Linear Corrective Devices of the Automatic Control System by the Integral Quadratic Criterion

2021 ◽  
pp. 55-74
Author(s):  
Badri Gvasalia ◽  
Keyword(s):  
Control System ◽  
Mathematical Programming ◽  
Automatic Control ◽  
Objective Function ◽  
Automatic Control System ◽  
Random Search ◽  
Extreme Points ◽  
Mathematical Programming Problem ◽  
Nonlinear Mathematical Programming ◽  
Optimal Values

When designing an automatic control system (ACS), it is important to determine the optimal values of the parameters of the correcting device according to any of the criteria. Recently, more and more publications have appeared on the use of the method of nonlinear mathematical programming for solving problems of synthesis of an automated control system. The article discusses a method for determining the optimal parameters of linear correcting devices according to the quadratic integral criterion. The novelty is the presentation of the above mentioned problem in the form of a nonlinear mathematical programming problem. To find a multiparametric, multiextremal, i.e. complex, objective function, a random search method is used. Also, a class of automatic control systems having one extreme objective function is highlighted. For this case, the theorems are proved, and the formula for determining extreme points is given in an analytical form. Numerical examples are also considered. Programs have been developed for implementing the corresponding algorithms on a computer in VBA language. The graphs of the corresponding transients are given.

scholarly journals Universal method for solving optimization problems under the conditions of uncertainty in the initial data

2021 ◽  
Vol 1 (4 (109)) ◽  
pp. 46-53
Author(s):  
Lev Raskin ◽  
Oksana Sira ◽  
Larysa Sukhomlyn ◽  
Yurii Parfeniuk
Keyword(s):  
Mathematical Programming ◽  
Objective Function ◽  
Membership Function ◽  
Fuzzy Numbers ◽  
Optimization Problems ◽  
Original Data ◽  
Structural Basis ◽  
Mathematical Programming Problem ◽  
Universal Method ◽  
Analytical Expression

This paper proposes a method to solve a mathematical programming problem under the conditions of uncertainty in the original data. The structural basis of the proposed method for solving optimization problems under the conditions of uncertainty is the function of criterion value distribution, which depends on the type of uncertainty and the values of the problem’s uncertain variables. In the case where independent variables are random values, this function then is the conventional theoretical-probabilistic density of the distribution of the random criterion value; if the variables are fuzzy numbers, it is then a membership function of the fuzzy criterion value. The proposed method, for the case where uncertainty is described in the terms of a fuzzy set theory, is implemented using the following two-step procedure. In the first stage, using the membership functions of the fuzzy values of criterion parameters, the values for these parameters are set to be equal to the modal, which are fitted in the analytical expression for the objective function. The resulting deterministic problem is solved. The second stage implies solving the problem by minimizing the comprehensive criterion, which is built as follows. By using an analytical expression for the objective function, as well as the membership function of the problem’s fuzzy parameters, applying the rules for operations over fuzzy numbers, one finds a membership function of the criterion’s fuzzy value. Next, one calculates a measure of the compactness of the resulting membership function of the fuzzy value of the problem’s objective function whose numerical value defines the first component of the integrated criterion. The second component is the rate of deviation of the desired solution to the problem from the previously received modal one. Absolutely similarly designed is the computational procedure for the case where uncertainty is described in the terms of a probability theory. Thus, the proposed method for solving optimization problems is universal in relation to the nature of the uncertainty in the original data. An important advantage of the proposed method is the ability to use it when solving any problem of mathematical programming under the conditions of fuzzily assigned original data, regardless of its nature, structure, and type

scholarly journals Optimum Design of Reinforced Cylindrical Shells Under Combined Axial Compression and Internal Pressure

2021 ◽  
Vol 24 (2) ◽  
pp. 50-58
Author(s):  
Heorhii V. Filatov ◽  
Keyword(s):  
Mathematical Programming ◽  
Internal Pressure ◽  
Objective Function ◽  
Programming Problem ◽  
Random Search ◽  
Cylindrical Shells ◽  
Mathematical Programming Problem ◽  
Stability Conditions ◽  
Search Area ◽  
Critical Stresses

This paper discusses the use of the random search method for the optimal design of single-layered rib-reinforced cylindrical shells under combined axial compression and internal pressure with account taken of the elastic-plastic material behavior. The optimality criterion is the minimum shell volume. The search area for the optimal solution in the space of the parameters being optimized is limited by the strength and stability conditions of the shell. When assessing stability, the discrete rib arrangement is taken into account. In addition to the strength and stability conditions of the shell, the feasible space is subjected to the imposition of constraints on the geometric dimensions of the structural elements being optimized. The difficulty in formulating a mathematical programming problem is that the critical stresses arising in optimally-compressed rib-reinforced cylindrical shells are a function of not only the skin and reinforcement parameters, but also the number of half-waves in the circumferential and meridional directions that are formed due to buckling. In turn, the number of these half-waves depends on the variable shell parameters. Consequently, the search area becomes non-stationary, and when formulating a mathematical programming problem, it is necessary to provide for the need to minimize the critical stress function with respect to the integer wave formation parameters at each search procedure step. In this regard, a method is proposed for solving the problem of optimally designing rib-reinforced shells, using a random search algorithm whose learning is carried out not only depending on the objective function increment, but also on the increment of critical stresses at each extremum search step. The aim of this paper is to demonstrate a technique for optimizing this kind of shells, in which a special search-system learning algorithm is used, which consists in the fact that two problems of mathematical programming are simultaneously solved: that of minimizing the weight objective function and that of minimizing the critical stresses of shell buckling. The proposed technique is illustrated with a numerical example.

A Tale of Two Entities

2021 ◽  
Vol 2 (2) ◽  
pp. 1-21
Author(s):  
Hossam ElHussini ◽  
Chadi Assi ◽  
Bassam Moussa ◽  
Ribal Atallah ◽  
Ali Ghrayeb
Keyword(s):  
Power Flow ◽  
Power Grid ◽  
Communication Protocols ◽  
Charging Infrastructure ◽  
Electric Vehicle Charging ◽  
Public Data ◽  
Simulation Based ◽  
Charging Stations ◽  
The Impact ◽  
Ev Charging

With the growing market of Electric Vehicles (EV), the procurement of their charging infrastructure plays a crucial role in their adoption. Within the revolution of Internet of Things, the EV charging infrastructure is getting on board with the introduction of smart Electric Vehicle Charging Stations (EVCS), a myriad set of communication protocols, and different entities. We provide in this article an overview of this infrastructure detailing the participating entities and the communication protocols. Further, we contextualize the current deployment of EVCSs through the use of available public data. In the light of such a survey, we identify two key concerns, the lack of standardization and multiple points of failures, which renders the current deployment of EV charging infrastructure vulnerable to an array of different attacks. Moreover, we propose a novel attack scenario that exploits the unique characteristics of the EVCSs and their protocol (such as high power wattage and support for reverse power flow) to cause disturbances to the power grid. We investigate three different attack variations; sudden surge in power demand, sudden surge in power supply, and a switching attack. To support our claims, we showcase using a real-world example how an adversary can compromise an EVCS and create a traffic bottleneck by tampering with the charging schedules of EVs. Further, we perform a simulation-based study of the impact of our proposed attack variations on the WSCC 9 bus system. Our simulations show that an adversary can cause devastating effects on the power grid, which might result in blackout and cascading failure by comprising a small number of EVCSs.

Nonlinear Optimal Design of Dynamic Mechanical Systems

1992 ◽  
Author(s):  
T. E. Potter ◽  
K. D. Willmert ◽  
M. Sathyamoorthy
Keyword(s):  
Objective Function ◽  
Optimization Problems ◽  
Iteration Process ◽  
Optimization Method ◽  
Linear Constraints ◽  
Sum Of Squares ◽  
Function Evaluation ◽  
Deformation Analysis ◽  
Nonlinear Constraints ◽  
Quadratic Constraints

Abstract Mechanism path generation problems which use link deformations to improve the design lead to optimization problems involving a nonlinear sum-of-squares objective function subjected to a set of linear and nonlinear constraints. Inclusion of the deformation analysis causes the objective function evaluation to be computationally expensive. An optimization method is presented which requires relatively few objective function evaluations. The algorithm, based on the Gauss method for unconstrained problems, is developed as an extension of the Gauss constrained technique for linear constraints and revises the Gauss nonlinearly constrained method for quadratic constraints. The derivation of the algorithm, using a Lagrange multiplier approach, is based on the Kuhn-Tucker conditions so that when the iteration process terminates, these conditions are automatically satisfied. Although the technique was developed for mechanism problems, it is applicable to any optimization problem having the form of a sum of squares objective function subjected to nonlinear constraints.

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