pso algorithm

tuned mass dampers are a combination of mass, spring and dampers. tuned mass dampers are set on a specific frequency range, when the structure is subjected to external force in the desired frequency range, TMD reduce the responses of the structure by creating a force against the movement direction of the structure. The most important limitation of TMD is providing a sufficient mass ratio in order to optimally control the structure. The inerter element is an element with two terminals that can produce a force proportional to the acceleration difference created in its two terminals. One of the distinguishing features of this element compared to other structural control tools is the possibility of changing the mass matrix of the structure. Nowadays, extensive research is being done in order to combine the inerter element with structural control systems. Adding an inerter element to conventional tuned mass dampers significantly increases the efficiency of TMD and removes the limitation of TMD to provide a suitable mass ratio. The placement position of the inerter element in the control system is very important. If the inerter element is placed between two inappropriate levels in the system, it will disrupt the function of absorbing dynamic vibrations and cause the responses to intensify. In this research, the optimization of the parameters of the inerter element combination with tuned mass dampers is done using the particle optimization algorithm and with the ability to generalize to all structures

Gradually, with the urban population growth and development of cities, water distribution networks (WDNs) gain significant importance. So the need for computerized modeling of WDNs is felt more than ever to understand the behavior of these systems. The most important problem with modeling of WDNs is consistency between the calculated and measured data. Setting the coefficients of the model via measured data is necessary. Model parameters include Hazen-Williams coefficients in the pipes, base demand and demand pattern coefficients at the nodes. The calculated and measured data mainly include pressure head at nodes, tank levels, and flow in pipes, that can be considered either in steady state or in an extended period condition. The aim of this paper is to investigate the performance of PSO algorithm for setting the Hazen Williams coefficients of WDN Models. For this purpose, five models of the PSO algorithm and three models of the ACO algorithm were made. The proposed method tested on a two-loop test example and a real water distribution network.

The concept of container unloading and loading in container ports for the purpose of unloading and loading is referred to as container allocation. This study assumes that the containers are transported between different segments of the port and must be allocated between the existing segments of the port for transport. The allocation is made to minimize costs. For a good and efficient modeling is written the relationship between the different sections.In this paper, the issue of the allocation of containers to ships, yards, customs, mainland and cranes is examined separately. Also, the problem of allocating ships to the berths is also studied. in both parts, the time of transportation and the capacity of the enclosures are limited in the problem. The literature review shows that the results obtained from solving this problem are not applicable in practice. After mathematical modeling, due to the NP-hardness of the problem, two innovative algorithms have been used to solve the problem. The first PSO method performs the assignment of ships to the dock, and then the second algorithm uses the GA method to allocate containers to different parts. Finally, the proposed algorithm is analyzed and compared. The results of the calculations show that the proposed algorithm has a very high performance in practice and in the real world.

In this paper, a crack detection method is presented to detect Euler-Bernoulli beams containing arbitrary number of transverse cracks. The proposed method uses the time domain signal of the free vibration response to provide the position and depth of cracking of the Euler-Bernoulli beam that is modeled with a modified stiffness using the Spring model, with high accuracy and precision. The time history responses used in this paper are nodal computational accelerations at certain points of the beam exposed to impact load. The acceleration of the nodes is calculated with the Newmark beta method at the edge of the elastic beam`s superelements. Initially, using the computational time history of the damaged beam and the analytical model of the Euler-Bernoulli beam, the objective function of the failure detection problem, to be optimized by particle swarm algorithm, is defined and, intensity and location of transverse cracks are calculated by solving the optimization problem in Matlab environment. In order to determine the accuracy of the proposed method, three beam samples with different cracks and loadings are considered. In the first sample, the crack supposed to be in the superelements of beam and the beam considered to be with four elements as superelements. The second one has ten elements and same loading as previous. The third one has twenty elements and the loading is on the second element. All of the loadings are impulse loads. The comparison of the results of a four elements beam with the primitive conditions shows that accuracy of the deducted results were exactly matched. For the ten element beam, the results were satisfying but in the twenty element beam with asymmetric loading, obtained results indicate imprecise match.</div>

To determine the accuracy of the developed model in real environmental conditions, different percentages of noise were added to the data of all three samples. These noise addition to data, contain 1, 3, 5 Percentages of noise.  The results show that the model presented in the presence of noise also provides accurate results and the model is not sensitive to the presence of noise in the data applied to three samples. Considering different number of elements in each sample, no convergence was observed, Also the results were not sensitive to the location of impact load applied on the samples.</div>

The results of this study indicated that asymmetric cracking and loading variation are very effective in predicting beam failure. The results also indicate that variable reduction is very effective on the accuracy of results.</div>

Having more cracks and therefore more elements to analyze will yield to less accurate results. To lessen these inaccuracies, it can be practical to achieve better results by assuming the location of crack is constant in the element length if the depth of crack be the matter of importance.</div>

The number of iterations that have been executed, indicate that the pace of convergences in the developed process is less than when PSO deployed solely. This speed rate for obtaining results makes the developed method practical for solving crack detection problems in structures.</div>
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Links have capacity which is their physical attribute, as soon as flow in link reaches capacity, in flow pattern of network, at upstream links queue appears and network becomes congested. Cordon Congestion pricing is one of the effective ways that can reduce overcrowding in the congested central districts of networks without any negative impact on whole of the network. The purpose of this study is to present a congestion pricing model considering link capacity constraint. To this purpose, a bi-level model is proposed, where in the upper level the optimal toll is determined, and in the lower level the equilibrium is guaranteed using a traffic assignment model. An algorithm based on particle swarm optimization (PSO) is presented as a solving method for upper level problem and Shahpar’s method is used to solve assignment problem is lower level. The proposed algorithm is applied on Sioux-falls network with and without the capacity constraint. Results show that optimal pricing is affected by road capacity information. In Sioux-falls network from 10 links entering cordon, 6 links get toll, while in the solution, regardless of capacity constraint, 8 links get toll. The total cost of the network in terms of pricing, considering links capacity, improves by 13.1% relative to the lack of pricing. This improvement is 0.38% for a situation where capacity is not seen. The total toll on the cordon is also reduced from 1.86 to 0.86 units.

Considering the importance of redesign of dams spillways to provide optimum dimensions, the hybrid meta-heuristic based approach of Particle Swarm Optimization (PSO), Gray Wolves (GWO) and Direct Search Optimization (DSO) were proposed. In this approach, the spillway volume, which indicates the amount of concrete and cost, is considered as the objective function and spillway height, number of cycles, apex length and angle of wall are considered as decision variables. By implementing the proposed model, based on the Ute dam labyrinth spillway data, the spillway optimal dimensions were determined and compared with the other studies result. The results represent the very good performance of the proposed approach in generating global optimal solution, and non-hybrid use of DSO algorithm is not recommended due to network size constraint, increased computational cost and failure to achieve optimal solution. The optimal dimensions led to concrete saving and reduction of costs to 64% compared to the existing dam design. Investigating the optimal dimension of trapezoidal labyrinth spillway indicates that increase the flow capacity of the spillway to 15760 cubic meters per second. Finally, the comparison of the optimal dimensions obtained with two trapezoidal and triangular sections showed that the optimal form for labyrinth spillway is triangular.

The interaction between the jets and the loose beds may cause scour hole formation. The scour hole developments may cause structural instability of the structures and increases the damage probability of the structures. Hence the scour hole dimensions estimation is an important subject for engineers. Many investigators worked on the effective parameters on scour hole dimensions due to plane wall jets. They have presented many different equations to estimate the scour hole dimensions. The equations may be used on a specific range of the effective parameters. Using the width range of the available experimental data the appropriate equations are developed. Using the dimensional analysis the non dimensional parameters such as Froude densimetric, Reynolds number, non-dimensional form of the sediment size, standard deviation of the sediment mixture, tailwater depth, non dimensional form of the channel width and non dimensional form of the time were obtained. Authors tried to use an optimization procedure to develop the equations. As, generally, solving the optimization models is impossible using the analytical procedure, recently new metaheuristic methods are used to find the optimum results. So, in this research PSO algorithm was used to find of the unknown exponents and coefficients leading to the best result of proposed equations. Two different algorithms local PSO (LPSO) and Global PSO (GPSO) were used to find the unknown coefficients and exponents. Sensitivity analysis of the algorithms showed that the algorithms proposed different coefficients and exponents for different values population. Among the proposed coefficients and exponents one set of them are the best with minimum error. Comparsion between the experimental data and previouse prposed equations confirms strong scatter. Hence, in this type of problem using the metaheuristic algorithm and sensitivity analysis are recommended. The analysis of the results showed that the scour hole depth due to plane wall jets, is increasing funcions of densimetric Froude number, tailwater depth, time, and non dimensional form of the channel width. However, this parameter is a decreasing function of sediment gradation and non dimensional form of the sediment size. Similar trends were also observed for maximum ridge height formed at the downstream of the scour hole. The distance of the maximum height of the ridge is also an increasing function of densimetric Froude number, time, non dimensional form of the channel width, and Reynolds number of the jet. However this parameter is an decreasing function of standard deviation of the sediment mixture and tailawter depth. The sensitivity analysis of the effective parameters on scour hole dimension to find the more effective parameters were conducted. The latter analysis showed that Reynolds number, non dimensional form of the sediment size and non dimensional form of time has secondary effect on scour hole dimensions due to plane wall jets. However, the jet Reynolds number has the secondary effect on temporal variations of scour hole dimensions. The latter parameters were omitted from the effective parameters on scour hole dimensions without sensitive decreasing of equation accuracy.

Dierent passive dampers have been presented in order to improve structural performance, and various investigations have been undertaken to nd their optimum distribution by dierent methods. In this paper, optimal distribution of TADAS dampers to improve the performance of a 3-story steel moment frame is investigated. This frame has the same loading condition, mass, geometry, and beam and column material, as the moment resisting frame of a 3-story SAC building located in Los Angeles. The design of the members of the frame does not satisfy ASCE41-06 criteria. A nonlinear static procedure, according to ASCE41-06 instruction, is used to analyze the frame under seismic load.
Based on the concept of the uniform distribution of deformation (UDD) algorithm, in order to obtain optimal design, structural resistance elements should be transferred from strong to weak portions. In this study, a modied UDD algorithm is used to achieve optimal distribution of dampers. This algorithm acquires the optimal stiness distribution of TADAS dampers, with respect to the demand to capacity ratio (DCR) of the stories. The DCR of each story is equal to the maximum DCR of elements in that story, which is calculated based on ASCE41-06 regulations. First, the proposed algorithm assigns minimum stiness to all dampers, then, increases TADAS stiness in stories that have DCR greater than the allowable value, and vice versa. This process continues until uniform distribution for the stories DCR is achieved.
Genetic and PSO algorithms are types of heuristic algorithms. Optimal distribution of dampers using these algorithms is also obtained and their results compare with the UDD algorithm. Heuristic methods utilize a stochastic search to nd optimum solution. First, they generate a population of solutions, then, nd proper solutions, with regard to the objective function, and in the next steps, attempt to produce better population. Finally, they converge to the optimum design.
The results show that the optimum stiness distribution of TADAS dampers is obtained when the distribution of stories DCR becomes uniform. Also, the UDD alogorithm acquires optimum distribution of dampers in fewer numbers of analyses in comparison with heuristic methods, because this algorithm uses engineering intelligence instead of stochastic search to nd an optimum solution.