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.

A Case of Biliary Fascioliasis by Fasciola gigantica in Turkey

Vedat Goral,Senem Senturk,Omer Mete,Mutallib Cicek,Berat Ebik,Be?ir Kaya 대한기생충학열대의학회 2011 The Korean Journal of Parasitology Vol.49 No.1

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.

Optimization of trusses under uncertainties with harmony search

Vedat Togan,Ayse T. Daloglu,Halil Karadeniz 국제구조공학회 2011 Structural Engineering and Mechanics, An Int'l Jou Vol.37 No.5

In structural engineering there are randomness inherently exist on determination of the loads, strength, geometry, and so on, and the manufacturing of the structural members, workmanship etc. Thus, objective and constraint functions of the optimization problem are functions that depend on those randomly natured components. The constraints being the function of the random variables are evaluated by using reliability index or performance measure approaches in the optimization process. In this study, the minimum weight of a space truss is obtained under the uncertainties on the load, material and crosssection areas with harmony search using reliability index and performance measure approaches. Consequently, optimization algorithm produces the same result when both the approaches converge. Performance measure approach, however, is more efficient compare to reliability index approach in terms of the convergence rate and iterations needed.

The Many Faces of Dissociation: Opportunities for Innovative Research in Psychiatry

Vedat Şar 대한정신약물학회 2014 CLINICAL PSYCHOPHARMACOLOGY AND NEUROSCIENCE Vol.12 No.3

It has been claimed that the progress of psychiatry has lagged behind that of other medical disciplines over the last few decades. This may suggest the need for innovative thinking and research in psychiatry, which should consider neglected areas as topicsof interest in light of the potential progress which might be made in this regard. This review is concerned with one such fieldof psychiatry: dissociation and dissociative disorders. Dissociation is the ultimate form of human response to chronic developmentalstress, because patients with dissociative disorders report the highest frequency of childhood abuse and/or neglectamong all psychiatric disorders. The cardinal feature of dissociation is a disruption in one or more mental functions. Dissociativeamnesia, depersonalization, derealization, identity confusion, and identity alterations are core phenomena of dissociative psychopathologywhich constitute a single dimension characterized by a spectrum of severity. While dissociative identity disorder (DID)is the most pervasive condition of all dissociative disorders, partial representations of this spectrum may be diagnosed as dissociativeamnesia (with or without fugue), depersonalization disorder, and other specified dissociative disorders such as subthresholdDID, dissociative trance disorder, acute dissociative disorders, and identity disturbances due to exposure to oppression. In addition to constituting disorders in their own right, dissociation may accompany almost every psychiatric disorder and operateas a confounding factor in general psychiatry, including neurobiological and psycho-pharmacological research. While an anti-dissociative drug does not yet exist, appropriate psychotherapy leads to considerable improvement for many patients withdissociative disorders.

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.

Static analysis of simply supported porous sandwich plates

Vedat Taskin,Pinar Aydan Demirhan 국제구조공학회 2021 Structural Engineering and Mechanics, An Int'l Jou Vol.77 No.4

In this study, it is aimed to analyze the bending of porous sandwich plates using the four-variable shear deformation theory. The core of the sandwich plate is assumed to be functionally graded, and face sheets are assumed to be isotropic. The pore distribution of the sandwich plate is considered even and uneven type of porosity distribution. Displacement fields are defined with four variable shear deformation theory. Equilibrium equations of porous sandwich plates are derived from virtual displacement principle. An analytical solution is obtained by Navier’s approach. Results are presented for uniformly and sinusoidally distributed loaded porous sandwich plates. Face sheet -core thickness ratio, porosity distribution, amount of porosity is investigated.

Observer-based friction compensation in heavy-duty parallel robot control

Kamil Vedat Sancak,Zeki Yagiz Bayraktaroglu 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.8

This paper presents an experimental study on friction compensation for the high-precision tracking control of parallel manipulators. A Luenberger-like observer (LLO) and an extended state observer (ESO) are designed and implemented in real-time control of a 6-DoF heavy-duty Stewart-Gough platform (SGP). The dynamic Lu-Gre model is used in the identification of friction. Performances of the proposed observer-based friction compensators are compared to those of a model-based compensator in computed torque control. Experimental results show that the observer-based compensators significantly improve the tracking performances in high speed motions. Among the investigated observers, the ESO results in minimum RMS error in position tracking. Improvement in position tracking at velocity reversals of the individual leg motions is also observed with the contribution of observer-based compensation. The observer error dynamics is exponentially stable, and the convergence rate can be arbitrarily increased by tuning the observer gain.

Optimization of trusses under uncertainties with harmony search

Togan, Vedat,Daloglu, Ayse T.,Karadeniz, Halil Techno-Press 2011 Structural Engineering and Mechanics, An Int'l Jou Vol.37 No.5

In structural engineering there are randomness inherently exist on determination of the loads, strength, geometry, and so on, and the manufacturing of the structural members, workmanship etc. Thus, objective and constraint functions of the optimization problem are functions that depend on those randomly natured components. The constraints being the function of the random variables are evaluated by using reliability index or performance measure approaches in the optimization process. In this study, the minimum weight of a space truss is obtained under the uncertainties on the load, material and cross-section areas with harmony search using reliability index and performance measure approaches. Consequently, optimization algorithm produces the same result when both the approaches converge. Performance measure approach, however, is more efficient compare to reliability index approach in terms of the convergence rate and iterations needed.

Solidification Microstructures and Carbides Morphology in Rapidly Solidified Fe-Al-Cr-C Alloys

M. Vedat Akdeniz,Amdulla O. Mekhrabov 대한금속ᆞ재료학회 2008 METALS AND MATERIALS International Vol.14 No.4