Operations Research and Engineering Letters http://orel.unionnikolatesla.edu.rs/index.php/orel <p><em>Operations Research and Engineering Letters </em><em>(OREL)</em> publishes high-quality scientific papers that contribute significantly to the field of operational research and engineering science. The material published is of high quality and relevance, written in a manner that makes it accessible to all of this wide-ranging readership. Preference will be given to papers with decision-making implications to the practice of management and engineering.</p> <p><em>Aims and Scope</em></p> <p>The principal aim of the journal is to bring together the latest research and development in various fields of operational research. We would like to highlight that papers should refer to <a href="http://orel.unionnikolatesla.edu.rs/index.php/orel/aims" target="_blank" rel="noopener">Aims and scope</a>, but they are not limited to.</p> <p><em>Publication Frequency </em></p> <p>One issue per year is published online, but processed and accepted papers, with full bibliographic data, are added to the issue continuously over the whole year.</p> <p><em>Open Access</em></p> <p>This is an open-access journal which means that all content is freely available without charge to the user or his/her institution. Users are allowed to read, download, copy, distribute, print, search, or link to the full texts of the articles in this journal without asking prior permission from the publisher or the author.</p> <p><em>Publication fee</em></p> <p>There is no submission charge or publication fee. Publication in OREL is free of charge for the authors.</p> <p><em>Publisher</em></p> <p><a href="https://www.unionnikolatesla.edu.rs/en/about-university/faculties/faculty-of-civil-engineering" target="_blank" rel="noopener">Faculty of Civil Engineering Management, University “Union–Nikola Tesla”, Belgrade, Serbia</a></p> en-US orel@unionnikolatesla.edu.rs (Dragan Pamučar ) stefankoprivica@unionnikolatesla.edu.rs (Stefan Koprivica) Tue, 22 Mar 2022 00:00:00 +0000 OJS 3.3.0.8 http://blogs.law.harvard.edu/tech/rss 60 Estimation Strength Properties of UHPC Using Rough Set Algorithms http://orel.unionnikolatesla.edu.rs/index.php/orel/article/view/2 <p>During the hydration of cement, a heterogeneous structure is created within its composite materials and the properties of the material in a hardened state vary during the production period even though the mass proportion of the component materials in the concrete does not change. The rough set theory represents an advanced technique for treating the problems of uncertainty, ambiguity and inaccuracy, and it is suitable for assessing the attainment of the required mechanical properties of the composite based on its properties in early ages. This paper shows the results of tests completed on 12 mixtures of ultra-high performance concrete. The water/binder ratio and the content of silica fume and steel fibers are varied. By applying rough sets in the program solution Rosetta, an analysis of the parameters is carried out and the rules are given for deciding which of them can help in the process of making a choice as to the proportions of the component materials in the concrete mixture in relation to the required and attained mechanical properties.</p> Dragan Nikolić, Dragan Bojović Copyright (c) 2022 Dragan Nikolić, Dragan Bojović https://creativecommons.org/licenses/by/4.0 http://orel.unionnikolatesla.edu.rs/index.php/orel/article/view/2 Tue, 22 Mar 2022 00:00:00 +0000 Multi-Criteria Decision-Making in Construction Using the Software Decision Lab 2000 http://orel.unionnikolatesla.edu.rs/index.php/orel/article/view/3 <p>Decision making is a demanding process, and the consequences of making the wrong decision can have a negative impact on the business. To make successful decisions, a person must be able to predict the outcome of each option and determine which variant is best for a particular situation. In construction, the project manager must be able to decide which combination of construction machines is best for the execution of a job, although many criterions have influence on that decision. Multi-criteria decision-making is a complex process, but with the help of software problems can be quickly and successfully solved and solution can be analyzed. The aim of this paper is to show the support of Decision Lab 2000 software in the decision-making process in construction using the multi-criteria decision-making method PROMETHEE-GAIA.</p> Nataša Popović-Miletić Copyright (c) 2022 Nataša Popović-Miletić https://creativecommons.org/licenses/by/4.0 http://orel.unionnikolatesla.edu.rs/index.php/orel/article/view/3 Tue, 22 Mar 2022 00:00:00 +0000 The Application of the Multi Criteria Analysis in the Assessment of the Valuation of Real Estate http://orel.unionnikolatesla.edu.rs/index.php/orel/article/view/4 <p>Assessment value of the real estate indicates a professional opinion about the value, which is the result of systematic approach in the procedure of estimating the value of real estate. In complex problems the use of individual standard methods of evaluation of the real estate is not giving an acceptable result, so it is mandatory to use multi criteria analysis, that is the use of combined standard methods of evaluation and correct assessment of given data.</p> Slobodan Jovović, Zoran Živković Copyright (c) 2022 Slobodan Jovović, Zoran Živković https://creativecommons.org/licenses/by/4.0 http://orel.unionnikolatesla.edu.rs/index.php/orel/article/view/4 Tue, 22 Mar 2022 00:00:00 +0000 Application of Electre Methods of Multi Criteria Decision Making in Systems with Missing Data http://orel.unionnikolatesla.edu.rs/index.php/orel/article/view/5 <p>In the paper, we consider the French school of decision-making approach, known as ELECTRE methods, in situations when some alternatives are not valuated with all criteria. For this purpose, we introduced a modified concordance index. Finally, we gave a practical example.</p> Ivan Anić, Stefan Koprivica, Vule Aleksić Copyright (c) 2022 Ivan Anić, Stefan Koprivica, Vule Aleksić https://creativecommons.org/licenses/by/4.0 http://orel.unionnikolatesla.edu.rs/index.php/orel/article/view/5 Tue, 22 Mar 2022 00:00:00 +0000 Applications of Artificial Neural Networks in Multi-Criteria Decision-Making in Civil Engineering http://orel.unionnikolatesla.edu.rs/index.php/orel/article/view/6 <p>The paper deals with the multi-criteria decision making using Hopfield network which belongs to a class of artificial neural networks. The general procedure has been defined based on the application of Hopfield network. By using the model based on Hopfield auto-associative memory, the defined procedure has been applied for solving a specific problem, which is to select the best variant solution of the route of gas trunk line.</p> Ljubo Marković , Ljiljana Milić Marković , Nikola Gvozdović Copyright (c) 2022 Ljubo Marković , Ljiljana Milić Marković , Nikola Gvozdović https://creativecommons.org/licenses/by/4.0 http://orel.unionnikolatesla.edu.rs/index.php/orel/article/view/6 Tue, 22 Mar 2022 00:00:00 +0000 Evaluation of Subcontractor Selection Criteria and Comparison With Their Financial Performance Indicators http://orel.unionnikolatesla.edu.rs/index.php/orel/article/view/16 <p>The successful selection of subcontractors is a crucial process for any construction project. Many factors affect the subcontractor selection, and in most cases, the subcontractor is chosen based on the lowest bid. However, selecting an improper subcontractor can cause delay of works and delay in the project, low work quality, and additional resources. As the research methodology, a survey was carried out by 30 project managers, construction managers and site engineers participating in the construction sector as Main Contractor. This survey aimed to evaluate 20 subcontractors based on the evaluator's experience. For each subcontractor, financial performance indicators were calculated. The paper presents the connection between the survey results and financial ratios, improving the subcontractor's selection and the Main Contractor's decision-making process.</p> Stefan Koprivica Copyright (c) 2022 Stefan Koprivica https://creativecommons.org/licenses/by/4.0 http://orel.unionnikolatesla.edu.rs/index.php/orel/article/view/16 Mon, 29 Aug 2022 00:00:00 +0000 Novel Interval Valued T-Spherical Fuzzy Mclaurin Symmetric Mean Operators and Their Applications in Multi-Attribute Group Decision Making Problems http://orel.unionnikolatesla.edu.rs/index.php/orel/article/view/15 <p>Educational institutes play a significant role to build up a nation and developing society. Education is an important factor that can help a man to judge his destiny, and shape the coming future. This article aims to extend the concepts of interval-valued T-spherical fuzzy (IVTSF) set (IVTSFS) based on Maclaurin symmetric mean (MSM) operators. The main concentration of this manuscript is to study the interrelationship among any number of IVTSF numbers (IVTSFNs) by the use of Maclaurin symmetric mean (MSM) operators. We explore and develop IVTSF Maclaurin symmetric mean (IVTSFMSM) operator, IVTSF weighted MSM (IVTSFWMSM) operator, IVTSF dual MSM (IVTSFDMSM) operator, IVTSF weighted dual MSM (IVTSFWDMSM) operator. By using these examined operators, some special cases of the discovered operators are also established and their properties are examined. In addition, a procedure for handling multi-attribute group decision-making (MAGDM) techniques based on MSM operators in the IVTSF setting. &nbsp;A demonstrative example to check the applicability of the MSM operators of IVTSFSs is presented which established the selection of applicants. To show the supremacy of the newly established MSM operators, a comprehensive comparative study is designed numerically.</p> Kifayat Ullah, Abrar Hussain, Adeel Ahmad, Zeeshan Ali Copyright (c) 2022 Kifayat Ullah, Abrar Hussain, Adeel Ahmad, Zeeshan Ali https://creativecommons.org/licenses/by/4.0 http://orel.unionnikolatesla.edu.rs/index.php/orel/article/view/15 Mon, 29 Aug 2022 00:00:00 +0000 Concrete Crack Analysis in RC Elements Using Rough Set Theory http://orel.unionnikolatesla.edu.rs/index.php/orel/article/view/17 <p>The rough set theory is a relatively recent mathematical approach to definition and analysis of vagueness, ambiguity and uncertainty, and it is suitable tool in data mining system. The paper presents a decision rule modeling for classification and analysis the cause of concrete cracking in relation to time (in fresh or hardened concrete) and physical, chemical, thermal and load impact in uncertain environment. The model is based on stochastic approach and decision table is obtained by considering cracks characteristic as attribute set. It is shown that the objective decision rules for given parameters related to cracks classification can be formulated.</p> Dragan Nikolić, Dragan Bojović, Snežana Mitrović Copyright (c) 2022 Dragan Nikolić, Dragan Bojović, Snežana Mitrović https://creativecommons.org/licenses/by/4.0 http://orel.unionnikolatesla.edu.rs/index.php/orel/article/view/17 Mon, 29 Aug 2022 00:00:00 +0000