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A review of energy-efficient and sustainable construction scheduling supported with optimization tools
Borna Dasović, Uroš Klanšek, 2022, pregledni znanstveni članek

Opis: This article reviews the accomplishments of studies in which optimization tools were used to develop energy-efficient and sustainable construction schedules. With the increase in global awareness of environmental issues, the construction industry has been forced to explore innovative techniques to make the building process more energy-efficient and sustainable. Project managers can use optimization tools in their scheduling procedures to address these issues in the early stages of the project. Therefore, this paper examines different optimization-based construction scheduling methods and their impact on schedule energy efficiency and the three key sustainability goals: economic viability, social equity, and environmental protection. Such a review has not yet been conducted to the best of our knowledge. This research aims to fill the gap and contribute to understanding advanced optimization tools that can pave the way to energy-efficient and sustainable scheduling practices. After a brief introduction, the background of optimization-based construction scheduling techniques that aim to improve construction management and incorporate these aspects into the decision-making process is explained. Then, these approaches are addressed in detail. It is determined for each study whether it adopted energy efficiency goals and which sustainability dimensions it considered within the proposed optimization model. The results of this study indicate a wide heuristic algorithms application for complex scheduling problems. Meanwhile, mathematical programming is still quite unexplored, especially methods that utilize algebraic modeling languages. This study provides a foundation for further research by addressing the current reach in development and possible knowledge gaps that could be researched in future studies. The paper also discusses the advantages and limitations of different approaches and illustrates the potential for utilizing these methods. Supported by the main review findings, conclusions and recommendations for further research are provided.
Ključne besede: construction, project management, optimization tools, scheduling, sustainability, energy efficiency
Objavljeno v DKUM: 26.09.2023; Ogledov: 19; Prenosov: 0
.pdf Celotno besedilo (1,20 MB)
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Potential of using waste materials in flexible pavement structures identified by optimization design approach
Primož Jelušič, Süleyman Gücek, Bojan Žlender, Cahit Gürer, Rok Varga, Tamara Bračko, Murat V. Taciroğlu, Burak E. Korkmaz, Şule Yarcı, Borut Macuh, 2023, izvirni znanstveni članek

Opis: This paper presents the design of geosynthetic reinforced flexible pavements and their modification by incorporating waste materials into bonded and unbonded layers of the pavement structure. The optimal design of flexible pavements was achieved by minimizing the construction cost of the pavement. The incorporation of waste materials into the pavement structure affects the material properties. Therefore, along with the traffic load, the effects of the material properties of the asphalt concrete, base layer, sub-base layer, and subgrade were analyzed in terms of pavement structure costs and CO2 emissions of materials used in pavement construction. In addition, a comparison was made between pavements with and without geosynthetic reinforcement in terms of design, optimum construction cost, and CO2 emissions. The use of geosynthetics is even more effective in pavement structures that contain waste materials in an unbound layer, both in terms of cost and CO2 emissions. The minimum value of the California Bearing Ratio of the subgrade was determined at which the use of geosynthetic reinforcement for pavement structure with and without the inclusion of waste materials is economically and sustainably justified. The use of geosynthetics could result in a 15% reduction in pavement structure cost and a 9% reduction in CO2 emissions due to the reduced thickness of unbound layers. In addition, reducing the CBR of the unbound layer from 100% to 30% due to the inclusion of waste materials implies a cost increase of up to 13%. While the present study is based on an empirical pavement design method in which pavement thickness is limited by the pavement thickness index, the same minimum thicknesses are obtained in the optimization process regardless of whether the objective function is the minimum construction cost or minimum CO2 emissions.
Ključne besede: pavement design, waste materials, optimization, minimum construction cost, CO2 emissions, geosynthetics, waste management
Objavljeno v DKUM: 18.09.2023; Ogledov: 95; Prenosov: 9
.pdf Celotno besedilo (6,20 MB)
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Optimization of conditions for enzymatic decomposition of fibrous cotton textile waste : diplomsko delo univerzitetnega študijskega programa I. stopnje
Stela Tashkova, 2023, diplomsko delo

Opis: The main goal of this thesis was to optimize the conditions under which a 100 % cellulose material enzymatically decomposes. Waste textile and waste cellulose represent a large source of carbon that can be used in the production of value–added chemicals. The main goal of this diploma thesis was to test different conditions for the enzymatic decomposition of cellulose waste such as temperature range, enzymes concentration and different buffer composition. We started with the optimization of the temperature and tested how the reaction proceeds at three different temperatures (50, 55 and 60 °C). Here, the main goal was to check how the enzymatic mixture we used acts at these three different environments, thus how much will the material decompose. The results showed that the optimal temperature for the decomposition of cellulose is 50 °C. The second part of the diploma thesis evaluates if a higher concentration of enzymes would get better results regarding cellulose waste decomposition. The results here showed that an increased enzyme concentration does not improve the efficiency of the reaction under the tested conditions. Additionally, two different buffers 0.1 M NH4Cl and 0.1 M (NH4)2SO4 were tested as environments for the enzymatic degradation of cellulose waste. We got a higher glucose concentration in the reaction with (NH4)2SO4, as well as less variability of the pH, which led to a lower NaOH consumtion.
Ključne besede: enzymatic cellulose decomposition, optimization, temperature effect, NH4Cl, (NH4)2SO4, Cellic® CTec2
Objavljeno v DKUM: 13.09.2023; Ogledov: 47; Prenosov: 4
.pdf Celotno besedilo (13,48 MB)

Indoor positioning system based on bluetooth low energy technology and a nature-inspired optimization algorithm
Primož Bencak, Darko Hercog, Tone Lerher, 2022, izvirni znanstveni članek

Opis: Warehousing is one of the most important activities in the supply chain, enabling competitive advantage. Effective management of warehousing processes is, therefore, crucial for achieving minimal costs, maximum efficiency, and overall customer satisfaction. Warehouse Management Systems (WMS) are the first steps towards organizing these processes; however, due to the human factor involved, information on products, vehicles and workers may be missing, corrupt, or misleading. In this paper, a cost-effective Indoor Positioning System (IPS) based on Bluetooth Low Energy (BLE) technology is presented for use in Intralogistics that works automatically, and therefore minimizes the possibility of acquiring incorrect data. The proposed IPS solution is intended to be used for supervising order-picker movements, movement of packages between workstations, and tracking other mobile devices in a manually operated warehouse. Only data that are accurate, reliable and represent the actual state of the system, are useful for detailed material flow analysis and optimization in Intralogistics. Using the developed solution, IPS technology is leveraged to enhance the manually operated warehouse operational efficiency in Intralogistics. Due to the hardware independence, the developed software solution can be used with virtually any BLE supported beacons and receivers. The results of IPS testing in laboratory/office settings show that up to 98% of passings are detected successfully with time delays between approach and detection of less than 0.5 s.
Ključne besede: warehousing, indoor positioning systems, bluetooth low energy, particle swarm optimization, nature–inspired algorithm, intralogistics
Objavljeno v DKUM: 17.08.2023; Ogledov: 84; Prenosov: 11
.pdf Celotno besedilo (2,42 MB)
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Repositioning and optimal re-allocation of empty containers : a review of methods, models, and applications
Alaa Abdelshafie, May Salah, Tomaž Kramberger, Dejan Dragan, 2022, izvirni znanstveni članek

Opis: Managing empty-container movements is one of the most challenging logistics problems in the shipping field. With the growth of global trade imbalance, the repositioning process has become necessary, immediately after emptying a container. The main contribution of this research paper is to enrich the most frequently used methods, models, and applications in the literature, for relaxing the empty-container-repositioning problem. The article presents practices that vary between organizational policies, technical solutions, and modelling applications. A review of optimization models has been used for comparisons, based on specified criteria, such as the time frame, inputs, outputs, scale of the project, and value. Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) was applied through the online database Web of Science (WOS). It gives a comprehensive description of all the relevant published documents. On the basis of conducting a brief systematic review, future research opportunities have been determined, considering the emerging phenomena in container transport chains.
Ključne besede: shipping industry, container-transportation management, empty-container repositioning, optimization methods
Objavljeno v DKUM: 08.08.2023; Ogledov: 83; Prenosov: 11
.pdf Celotno besedilo (886,56 KB)
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Empirical modeling of liquefied nitrogen cooling impact during machining Inconel 718
Matija Hriberšek, Lucijano Berus, Franci Pušavec, Simon Klančnik, 2020, izvirni znanstveni članek

Opis: This paper explains liquefied nitrogen’s cooling ability on a nickel super alloy called Inconel 718. A set of experiments was performed where the Inconel 718 plate was cooled by a moving liquefied nitrogen nozzle with changing the input parameters. Based on the experimental data, the empirical model was designed by an adaptive neuro-fuzzy inference system (ANFIS) and optimized with the particle swarm optimization algorithm (PSO), with the aim to predict the cooling rate (temperature) of the used media. The research has shown that the velocity of the nozzle has a significant impact on its cooling ability, among other factors such as depth and distance. Conducted experimental results were used as a learning set for the ANFIS model’s construction and validated via k-fold cross-validation. Optimization of the ANFIS’s external input parameters was also performed with the particle swarm optimization algorithm. The best results achieved by the optimized ANFIS structure had test root mean squared error (test RMSE) = 0.2620, and test R$^2$ = 0.8585, proving the high modeling ability of the proposed method. The completed research contributes to knowledge of the field of defining liquefied nitrogen’s cooling ability, which has an impact on the surface characteristics of the machined parts.
Ključne besede: cryogenic machining, cooling impact, Inconel 718, machine learning, adaptive neuro-fuzzy inference system, particle swarm optimization
Objavljeno v DKUM: 14.07.2023; Ogledov: 120; Prenosov: 9
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Assembly line optimization using MTM time standard and simulation modeling—A case study
Matic Breznik, Borut Buchmeister, Nataša Vujica-Herzog, 2023, izvirni znanstveni članek

Opis: This study presents an approach to solving the assembly line balancing problem (ALBP) using the Methods-Time Measurement (MTM) time standard and simulation software. ALBP is a common problem in manufacturing where a set of tasks with fixed times must be assigned to a series of sequential workstations in order to minimize the total idle time and reduce the assembly cost per product. This study uses MTM, a widely used production process scheduling method, to create a new time analysis of an assembly process that was previously balanced using the Work-Factor method and time study. This literature review shows that there are a lack of combinations of updated time analyses with newer simulation approaches in the current literature, and this was the motivation for the present work. An assembly line simulation was performed using Simio software to evaluate different design options and operating scenarios. The results show that the use of MTM and simulation can help minimize idle time and improve assembly line performance, thereby reducing costs and increasing efficiency. This study shows that the approach of using MTM and simulation is effective in solving ALBP and is a useful tool for manufacturing companies to improve the performance of their assembly lines and reduce costs.
Ključne besede: optimization, production planning, assembly line, MTM time standard, simulation, industry 4.0
Objavljeno v DKUM: 23.05.2023; Ogledov: 169; Prenosov: 15
.pdf Celotno besedilo (3,25 MB)

Algorithmic linearization improves Syringe-based extrusion in elastic systems using Hydrogel-based materials
Jernej Vajda, Luka Banović, Mihael Miško, Igor Drstvenšek, Marko Milojević, Uroš Maver, Boštjan Vihar, 2023, izvirni znanstveni članek

Opis: Accuracy and precision are essential in extrusion-based material handling such as three-dimensional (3D) bioprinting. However, the elasticity of components, backlash, variability of nozzle and cartridge shapes, etc. can lead to unpredictable printing results, which is further complicated by the wide range of rheologically diverse materials and complex sample designs. To address this issue, we present an algorithmic approach to compensate for the discrepancies between piston motion and material extrusion in syringe-based extrusion systems. This approach relies on cyclical, iterative optimization through rapid piston movements, which are adjusted based on extrusion analysis. In this work we establish a general theoretical framework for extrusion and link the rheological properties of prepared hydrogels with shear rates in a typical bioprinting process. The determined properties are compared with the success of the developed algorithm to modify machine instructions for precise material deposition of short, interrupted lines, as well as multi-layered scaffold structures. Overall, our approach provides a means of improving the accuracy and precision of complex extrusion-based bioprinting systems, without prior knowledge of set-up or material properties, making it highly versatile and suitable for a wide range of applications, particularly when the combined set-up and material properties are too complex for solely predictive approaches.
Ključne besede: 3D bioprinting, syringe extrusion, optimization, algorithm
Objavljeno v DKUM: 21.04.2023; Ogledov: 335; Prenosov: 15
.pdf Celotno besedilo (3,38 MB)

The 100-digit challenge : algorithm jDE100
Janez Brest, Mirjam Sepesy Maučec, Borko Bošković, objavljeni znanstveni prispevek na konferenci

Opis: Real parameter optimization problems are often very complex and computationally expensive. We can find such problems in engineering and scientific applications. In this paper, a new algorithm is proposed to tackle the 100-Digit Challenge. There are 10 functions representing 10 optimization problems, and the goal is to compute each function’s minimum value to 10 digits of accuracy. There is no limit on either time or the maximum number of function evaluations. The proposed algorithm is based on the self-adaptive differential evolution algorithm jDE. Our algorithm uses two populations and some other mechanisms when tackling the challenge. We provide the score for each function as required by the organizers of this challenge competition.
Ključne besede: differential evolution, optimization, global optimum, accuracy
Objavljeno v DKUM: 23.01.2023; Ogledov: 198; Prenosov: 9
.pdf Celotno besedilo (425,62 KB)
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