An integrated particle swarm optimizer for optimization of truss structures with discrete variables

Ali Mortazavi,Vedat Toğan,Ayhan Nuhoğlu 국제구조공학회 2017 Structural Engineering and Mechanics, An Int'l Jou Vol.61 No.3

This study presents a particle swarm optimization algorithm integrated with weighted particle concept and improved fly-back technique. The rationale behind this integration is to utilize the affirmative properties of these new terms to improve the search capability of the standard particle swarm optimizer. Improved fly-back technique introduced in this study can be a proper alternative for widely used penalty functions to handle existing constraints. This technique emphasizes the role of the weighted particle on escaping from trapping into local optimum(s) by utilizing a recursive procedure. On the other hand, it guaranties the feasibility of the final solution by rejecting infeasible solutions throughout the optimization process. Additionally, in contrast with penalty method, the improved fly-back technique does not contain any adjustable terms, thus it does not inflict any extra ad hoc parameters to the main optimizer algorithm. The improved fly-back approach, as independent unit, can easily be integrated with other optimizers to handle the constraints. Consequently, to evaluate the performance of the proposed method on solving the truss weight minimization problems with discrete variables, several benchmark examples taken from the technical literature are examined using the presented method. The results obtained are comparatively reported through proper graphs and tables. Based on the results acquired in this study, it can be stated that the proposed method (integrated particle swarm optimizer, iPSO) is competitive with other metaheuristic algorithms in solving this class of truss optimization problems.

Time-Cost Trade-off Optimization of Construction Projects using Teaching Learning Based Optimization

Vedat Toğan,M. Azim Eirgash 대한토목학회 2019 KSCE Journal of Civil Engineering Vol.23 No.1

Accelerating the project schedule raises the total cost of the project and shall be efficient only up to a certain limit. A Time-Cost Trade-off Problem (TCTP) is utilized to detect the optimal set of time-cost alternatives to enhance the overall construction project benefit. In this study, to find a set of Pareto front solutions, a multi-objective optimization model which is based on the Teaching- Learning Based Optimization (TLBO) incorporated with the Modified Adaptive Weight Approach (MAWA), is proposed. Four examples of construction projects taken from the technical literature ranging from 7 to 63 activities are investigated to show the performance of the MAWA-TLBO. The results are compared with those obtained using previously proposed models considering the optimal or near optimal solutions. It was found that the MAWA-TLBO algorithm works effectively for the TCTP in construction engineering and management field.

Optimizing of Discrete Time–Cost in Construction Projects Using New Adaptive Weight Formulations

Vedat Toğan,Neslihan Berberoğlu,Tayfun Dede 대한토목학회 2022 KSCE JOURNAL OF CIVIL ENGINEERING Vol.26 No.2

In this paper, four new adaptive weight formulations are developed to enhance the performance of traditional Modified Adaptive Weight Approach (MAWA), which is the simplest way for solving the multi-objective optimization of discrete time-cost trade-off problem (DTCTP). Several numerical experiments are conducted to validate the newly proposed formulations. In addition, three meta-heuristic-based optimization algorithms are utilized to examine the variations within the results of the test instances. The proposed model provides several ways to solve DTCTP, as it includes different formulations and optimization algorithms. So, this model performs well for the medium and large-scale time-cost optimization problems on contrary to the traditional MAWA.

A multi-objective decision making model based on TLBO for the time – cost trade-off problems

Mohammad A. Eirgash,Vedat Toğan,Tayfun Dede 국제구조공학회 2019 Structural Engineering and Mechanics, An Int'l Jou Vol.71 No.2

In a project schedule, it is possible to reduce the time required to complete a project by allocating extra resources forcritical activities. However, accelerating a project causes additional expense. This issue is addressed by finding optimal set of timecostalternatives and is known as the time-cost trade-off problem in the literature. The aim of this study is to identify the optimal setof time-cost alternatives using a multiobjective teaching-learning-based optimization (TLBO) algorithm integrated with the nondominatedsorting concept and is applied to successfully optimize the projects ranging from a small to medium large projects. Numerical simulations indicate that the utilized model searches and identifies optimal / near optimal trade-offs between project timeand cost in construction engineering and management. Therefore, it is concluded that the developed TLBO-based multiobjectiveapproach offers satisfactorily solutions for time–cost trade-off optimization problems.

Design of pin jointed structures using teaching-learning based optimization

Vedat Toğan 국제구조공학회 2013 Structural Engineering and Mechanics, An Int'l Jou Vol.47 No.2

A procedure employing a Teaching-Learning Based Optimization (TLBO) method is developed to design discrete pin jointed structures. TLBO process consists of two parts: the first part represents learning from teacher and the second part illustrates learning by interaction among the learners. The effectiveness of the TLBO method is demonstrated on the four design optimization problems. The results are compared with those obtained using other various evolutionary optimization methods considering the best solution, average solution, and computational effort. Consequently, the TLBO algorithm works effectively and demonstrates remarkable performance for the optimization of engineering design applications.

A teaching learning based optimization for truss structures with frequency constraints

Tayfun Dede,Vedat Toğan 국제구조공학회 2015 Structural Engineering and Mechanics, An Int'l Jou Vol.53 No.4

Natural frequencies of the structural systems should be far away from the excitation frequency in order to avoid or reduce the destructive effects of dynamic loads on structures. To accomplish this goal, a structural optimization on size and shape has been performed considering frequency constraints. Such anoptimization problem has highly nonlinear property. Thus, the quality of the solution is not independent of the optimization technique to be applied. This study presents the performance evaluation of the recently proposed meta-heuristic algorithm called Teaching Learning Based Optimization (TLBO) as an optimization engine in the weight optimization of the truss structures under frequency constraints. Some examples regarding the optimization of trusses on shape and size with frequency constraints are solved. Also, the results obtained are tabulated for comparison. The results demonstrated that the performance of the TLBO is satisfactory. Additionally, TLBO is better than other methods in some cases.

A Novel Injectable pH–Temperature Sensitive Hydrogel Containing Chitosan–Insulin Electrosprayed Nanosphere Composite for an Insulin Delivery System in Type I Diabetes Treatment

Thuy An Trinh,Thai Minh Duy Le,Hoang Gia Vinh Ho,Thi Cam Thach To,Vu Viet Linh Nguyen,Dai Phu Huynh,Doo Sung Lee 한국고분자학회 2021 한국고분자학회 학술대회 연구논문 초록집 Vol.46 No.1

Faculty of Materials Technology, Ho Chi Minh University of Technology (HCMUT)/Vietnam National University Ho Chi Minh City; ¹School of Chemical Engineering and Theragnostic Macromolecules Research Center, Sungkyunkwan University; ²Vietnam National University Ho Chi Minh City/National Key Laboratory of Polymer and Composite Materials, Ho Chi Minh University of Technology, Vietnam National University; ³Faculty of Materials Technology, Ho Chi Minh University of Technology (HCMUT)/ Vietnam National University Ho Chi Minh City/Research Center for Polymeric Materials, Ho Chi Minh University of Technology, Vietnam National University In this research, a novel insulin composite delivery system was prepared and characterized. Insulin drug was loading in chitoshan nanospheres using electrospraying method, a pH- and temperature-sensitive biodegradable hydrogel, which is an oligomer serine-poly(lactide)-poly(ethylene glycol)-poly (lactide)-oligomer serine (OS-PLA-PEG-PLA-OS) pentablock copolymer was used as a matrix to containing chitosan–insulin electro sprayed nanospheres (CIN). The properties of the OS-PLA-PEG-PLA-OS pentablock copolymer and the chitosan–insulin nanoparticles such as sol-gel transition, degradation in vitro and in vivo were characterized. The results showed that the chitosan–insulin nanospheres uniformly distributed in the matrix had a reinforcing effect on the mechanical properties and prolonged the degradation time of the hydrogel depot under body conditions. In addition, the cytotoxicity experiment results indicate that the composite could be used as a biomaterial for drug delivery system. The composite solutions accommodating different concentrations of the chitosan–insulin nanospheres were subcutaneously injected into induced diabetic BALB/c mice to study the in vivo insulin-release profile. The result showed that insulin concentrations in blood plasma were maintained at a steady-state level. Furthermore, the bio-properties of the insulin were retained and it showed a blood glucose level reducing effect for more than 60 hours after injection to a streptozotocin (STZ)-induced diabetic mouse model. The results suggested that this injectable pH–temperature sensitive hydrogel containing chitosan– insulin electro sprayed nanosphere composites has promising potential applications for type 1 diabetes treatment.

의사위성을 이용한 광역보정정보 전송시스템에 대한 실시험

권금철(Keum-Cheol Kwon),양철관(Cheol-Kwan Yang),윤기영(Ki-Young Yun),이정훈(Jung-Hoon Lee),안대성(Dae-Sung An),김강토(Kang-To Kim),심덕선(Duk-Sun Shim) 대한전기학회 2014 정보 및 제어 심포지엄 논문집 Vol.2014 No.10

In this paper, results of real-time experiments of WA-DGNSS transmission system using pseudolite are presented. Correction data and integrity information is transmitted to users by network communication between master station and pseudolite. And performance of WA-DGNSS transmission system is tested by software and hardware GPS receiver. By results of the experiments, we show that correction data is well transmitted to GPS receiver without errors and the navigation error is decreased.

<방진산군수가>식 대칭표현형 연시조들의 해석

양희철 청주대학교 인문과학연구소 2011 人文科學論集 Vol.42 No.-

This treatise looked upon the structure, subject, and typicality of the linked Si-Jos having the tpye of the symmetrical expression in <Banjinsangunsuga>, using the method of the internal deviation and the tertiary deviation. The typicality follow as; First typicality is the fact that each unit(or Si-Jo) in the work composite the symmetrical expressions and the deviant expressions which have the symmetrical axis in the central unit(or one Si-Jo) or other unit(or Si-Jo). Second typicality is the fact that the symmetrical expressions and the deviant expressions hint the structure in the work, because the symmetrical expressions and the deviant expressions converge three point(the symmetrical axis, first unit(or Si-Jo), last unit(or Si-Jo). Third typicality is the fact that we discover the structure of the introduction-main discourse-conclusion or the structure of the introduction-development-turn-conclusion in the linked Si-Jos having the tpye of the symmetrical expression in <Banjinsangunsuga>. Fourth typicality is the fact that the divison(initial part, middle part, final part) of the work by the symmetrical expressions and the deviant expressions correspond with the structure of the introduction-main discourse-conclusion or the structure of the introduction-development-turn-conclusion.

Delay-and-Multiply 방법을 이용한 Galileo CBOC 신호 획득

김강토(Kang-To Kim),안대성(Dae-Sung An),심덕선(Duk-Sun Shim) 대한전기학회 2016 대한전기학회 학술대회 논문집 Vol.2016 No.7