teaching–learning-based optimization
در نشریات گروه عمران-
International Journal of Optimization in Civil Engineering, Volume:12 Issue: 3, Summer 2022, PP 399 -410
Today, due to the complexity of engineering problems and at the same time the advancement of computer science, the use of machine learning (ML) methods and soft computing methods in solving engineering problems has been considered by many researchers. These methods can be used to find accurate estimates for problems in various scientific fields. This paper investigates the effectiveness of the Adaptive Network-Based Fuzzy Inference System (ANFIS) hybridized with Teaching Learning Based Optimization Algorithm (TLBO), to predict the ultimate strength of columns with square and rectangular cross-sections, confide with various fiber-reinforced polymer (FRP) sheets. In previous studies by many researchers, several experiments have been conducted on concrete columns confined by FRP sheets. The results indicate that FRP sheets effectively increase the compressive strength of concrete columns. Comparing the results of ANFIS-TLBO with the experimental findings, which were agreeably consistent, demonstrated the ability of ANFIS-TLBO to estimate the compressive strength of concrete confined by FRP. Also, the comparison of RMSE, SD, and R2 for ANFIS-TLBO and the studies of different researchers show that the ANFIS-TLBO approach has a good performance in estimating compressive strength. For example, the value of R2 in the proposed method was 0.92, while this parameter was 0.87 at best among the previous studies. Also, the obtained error in the prediction of the proposed model is much lower than the obtained error in the previous studies. Hence, the proposed model is more efficient and works better than other techniques.
Keywords: ANFIS, Teaching Learning Based Optimization, FRP, compressive strength -
International Journal of Optimization in Civil Engineering, Volume:12 Issue: 2, Spring 2022, PP 245 -278
As a novel strategy, Quantum-behaved particles use uncertainty law and a distinct formulation obtained from solving the time-independent Schrodinger differential equation in the delta-potential-well function to update the solution candidates’ positions. In this case, the local attractors as potential solutions between the best solution and the others are introduced to explore the solution space. Also, the difference between the average and another solution is established as a new step size. In the present paper, the quantum teacher phase is introduced to improve the performance of the current version of the teacher phase of the Teaching-Learning-Based Optimization algorithm (TLBO) by using the formulation obtained from solving the time-independent Schrodinger equation predicting the probable positions of optimal solutions. The results show that QTLBO, an acronym for the Quantum Teaching- Learning- Based Optimization, improves the stability and robustness of the TLBO by defining the quantum teacher phase. The two circulant space trusses with multiple frequency constraints are chosen to verify the quality and performance of QTLBO. Comparing the results obtained from the proposed algorithm with those of the standard version of the TLBO algorithm and other literature methods shows that QTLBO increases the chance of finding a better solution besides improving the statistical criteria compared to the current TLBO.
Keywords: quantum-inspired evolutionary algorithm, teaching-learning-based optimization, population-based algorithm, circulant truss, quantum behaved particles, quantum teacher, frequency constraint -
International Journal of Optimization in Civil Engineering, Volume:11 Issue: 3, Summer 2021, PP 497 -513
The optimal design of dome structures is a challenging task and therefore the computational performance of the currently available techniques needs improvement. This paper presents a combined algorithm, that is supported by the mixture of Charged System Search (CSS) and Teaching-Learning-based optimization (TLBO). Since the CSS algorithm features a strong exploration and may explore all unknown locations within the search space, it is an appropriate complement to enhance the optimization process by solving the weaknesses with using another optimization algorithm’s strong points. To enhance the exploitation ability of this algorithm, by adding two parts of Teachers phase and Student phase of TLBO algorithm to CSS, a method is obtained that is more efficient and faster than standard versions of these algorithms. In this paper, standard optimization methods and new hybrid method are tested on three kinds of dome structures, and the results show that the new algorithm is more efficient in comparison to their standard versions.
Keywords: dome structures, charged system search, optimum design, teaching-learning-based optimization, structural optimization -
در مطالعه ی حاضر، یک روش جدید به روزرسانی مدل بر مبنای پارامترهای مودال اصلی سازه (بسامدهای طبیعی و شکل های مودی متناظر) ارایه شده است. بدین منظور، یک تابع ترکیبی ارتعاش محور با هدف کمینه سازی اختلاف بین مشخصات سازه ی اندازه گیری شده و مدل تحلیلی تعریف شده است. به منظور کاهش آثار نوفه، یک تابع جریمه بر تابع هدف اعمال شده است. برای حل مسیله ی شناسایی آسیب از الگوریتم بهینه یاب مبتنی بر آموزش و یادگیری استفاده شده است. جهت ارزیابی تابع هدف، سه مثال عددی بررسی شده است. چالش هایی نظیر اثر نوفه و تابع جریمه در نتایج شناسایی آسیب مطالعه شده است. همچنین مطالعه یی برای مقایسه ی تابع هدف پیشنهادی با سه تابع هدف دیگر مبتنی بر اطلاعات مودال انجام شده است. نتایج نشان می دهند که روش پیشنهادی با اعمال تابع جریمه و به کار بردن الگوریتم بهینه سازی مبتنی بر آموزش و یادگیری می تواند یک روش قابل اطمینان و پایدار در شناسایی آسیب سازه ها محسوب شود.
کلید واژگان: شناسایی آسیب، روش به روزرسانی مدل، پارامترهای مودال، تابع هدف، الگوریتم بهینه سازی مبتنی بر آموزش و یادگیریEngineering structures are prone to damage over their service life as a result of natural disaster so that damage spreading may lead to many casualties. In order to prevent these catastrophic events, early damage detection must be carried out. By considering these issues, numerous structural damage detection methods have been proposed by many researchers in the last few decades. Among all sorts of methods developed for damage detection in structures, vibration-based methods due to their simplicity and applicability are highly favored by many researchers. The basic conceptual of the vibration-based methods is that modal parameters (natural frequencies and their associated mode shapes) are functions of the physical properties of the structure (mass, damping, and stiffness). Therefore, changes in the physical properties will cause changes in the modal properties. A class of vibration-based methods is identified and damages are quantified using the model updating approach. In these methods, an objective function defined in terms of the discrepancies between the analytical model and real structural system is minimized as an optimization problem. In this paper, a novel model updating method is presented based on a structure’s main modal parameters (natural frequencies and their corresponding modal shapes). For this purpose, a hybrid vibration-based objective function is proposed to minimize the differences between the structure’s properties and the analytical model. A penalty function is integrated into the objective function to reduce the effects of noise in damage detection and uncertainties in the assessment procedure. The Teaching-Learning-Based Optimization (TLBO) algorithm is applied to solve this problem as an optimization problem. This algorithm is inspired by the traditional learning process of students in school. The two main stages of this algorithm are the effect of the teacher’s knowledge on student learning by the convergence strategy and students learning from each other by the divergence strategy. To evaluate the applicability of the proposed objective function in detecting the location and intensity of the damage, three numerical cases are considered. These cases include an 8-story shear frame, a continuous beam, and a spatial truss. Different challenges such as the effect of noise on measured data and the effect of the penalty-function on results of damage detection were considered. Furthermore, a comparative study is investigated between the proposed objective function and three other objective functions developed based the main model parameters. The results demonstrated that the proposed method is a reliable and stable technique in damage prognosis in structures.
Keywords: Damage detection, model updating method, modal parameters, objective function, Teaching–learning-based optimization -
Journal of the Structural Engineering and Geotechnics, Volume:10 Issue: 1, Winter and Spring 2020, PP 55 -72In this study, to enhance the optimization process, especially in the structural engineering field two well-known algorithms are merged together in order to achieve an improved hybrid algorithm. These two algorithms are Teaching-Learning Based Optimization (TLBO) and Harmony Search (HS) which have been used by most researchers in varied fields of science. The hybridized algorithm is called A Discrete Hybrid Teaching-Learning Based Optimization (DHTLBO) that is applied to optimization of truss structures with discrete variables. This new method is consisted of two parts: in the first part the TLBO algorithm applied as conventional TLBO for local optimization, in the second stage the HS algorithm is applied to global optimization and exploring all the unknown places in the search space. The new hybrid algorithm is employed to minimize the total weight of structures. Therefore, the objective function consists of member’s weight, which is depends on the form of stress and deflection limits. To demonstrate the efficiency and robustness of this new algorithm several truss structures which are optimized by most researchers are presented and then their results are compared to other meta-heuristic algorithm and TLBO and HS standard algorithms.Keywords: Discrete variables, Teaching-learning-based optimization, Harmony search, Size optimization, Truss structures, Structural optimization, Meta-heuristic algorithm
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International Journal of Optimization in Civil Engineering, Volume:10 Issue: 1, Winter 2020, PP 155 -180
Imperialist Competitive Algorithm, ICA is a meta-heuristic which simulates collapse of weak empires by more powerful ones that take possession of their colonies. In order to enhance performance, ICA is hybridized with proper features of Teaching-Learning-Based Optimization, TLBO. In addition, ICA walks are modified with an extra term to intensify looking for the global best solution. The number of control parameters and consequent tuning effort has been reduced in the proposed Imperialist Competitive Learner-Based Optimization, ICLBO with respect to ICA and several other methods. Efficiency and effectiveness of ICLBO is further evaluated treating a number of test functions in addition to continuous and discrete engineering problems. It is discussed and traced that balancing between exploration and exploitation is enhanced due to the proposed hybridization. Numerical results exhibit superior performance of ICLBO vs. ICA and a variety of other well-known meta-heuristics.
Keywords: hybrid optimization method, imperialist competitive algorithm, teaching-learning-based optimization, parameter reduction
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