Iskanje po katalogu digitalne knjižnice

Opis: Purpose – Ready-mix concrete delivery problem (RMCDP), a specific version of the vehicle routing problem (VRP), is a relevant supply-chain engineering task for construction management with various formulations and solving methods. This problem can range from a simple scenario involving one source, one material and one destination to a more challenging and complex case involving multiple sources, multiple materials and multiple destinations. This paper presents an Internet of Things (IoT)-supported active building information modeling (BIM) system for optimized multi-project ready-mix concrete (RMC) delivery. Design/methodology/approach – The presented system is BIM-based, IoT supported, dynamic and automatic input/output exchange to provide an optimal delivery program for multi-project ready-mix-concrete problem. The input parameters are extracted as real-time map-supported IoT data and transferred to the system via an application programming interface (API) into a mixed-integer linear programming (MILP) optimization model developed to perform the optimization. The obtained optimization results are further integrated into BIM by conventional project management tools. To demonstrate the features of the suggested system, an RMCDP example was applied to solve that included four building sites, seven eligible concrete plants and three necessary RMC mixtures. Findings – The system provides the optimum delivery schedule for multiple RMCs to multiple construction sites, as well as the optimum RMC quantities to be delivered, the quantities from each concrete plant that must be supplied, the best delivery routes, the optimum execution times for each construction site, and the total minimal costs, while also assuring the dynamic transfer of the optimized results back into the portfolio of multiple BIM projects. The system can generate as many solutions as needed by updating the real-time input parameters in terms of change of the routes, unit prices and availability of concrete plants. Originality/value – The suggested system allows dynamic adjustments during the optimization process, andis adaptable to changes in input data also considering the real-time input data. The system is based on spreadsheets, which are widely used and common tool that most stakeholders already utilize daily, while also providing the possibility to apply a more specialized tool. Based on this, the RMCDP can be solved using both conventional and advanced optimization software, enabling the system to handle even large-scale tasks as necessary.
Ključne besede: active building information modeling, BIM, internet of things, IoT, multi-project environment, optimization, ready-mix-concrete delivery, RMC
Objavljeno v DKUM: 11.09.2024; Ogledov: 32; Prenosov: 0

Opis: Distribution is one of the major sources of carbon emissions and this issue has been addressed by Green Vehicle Routing Problem (GVRP). This problem aims to fulfill the demand of a set of customers using a homogeneous fleet of Alternative Fuel Vehicles (AFV) originating from a single depot. The problem also includes a set of Alternative Fuel Stations (AFS) that can serve the AFVs. Since AFVs started to operate very recently, Alternative Fuel Stations servicing them are very few. Therefore, the driving span of the AFVs is very limited. This makes the routing decisions of AFVs more difficult. In this study, we formulated a multi-objective optimization model of Green Vehicle Routing Problem with two conflicting objective functions. While the first objective of our GVRP formulation aims to minimize total CO2 emission, which is proportional to the distance, the second aims to minimize the maximum traveling time of all routes. To solve this multi-objective problem, we used �-constraint method, a multi-objective optimization technique, and found the Pareto optimal solutions. The problem is formulated as a Mixed-Integer Linear Programming (MILP) model in IBM OPL CPLEX. To test our proposed method, we generated two hypothetical but realistic distribution cases in Izmir, Turkey. The first case study focuses on an inner-city distribution in Izmir, and the second case study involves a regional distribution in the Aegean Region of Turkey. We presented the Pareto optimal solutions and showed that there is a tradeoff between the maximum distribution time and carbon emissions. The results showed that routes become shorter, the number of generated routes (and therefore, vehicles) increases and vehicles visit a lower number of fuel stations as the maximum traveling time decreases. We also showed that as maximum traveling time decreases, the solution time significantly decreases.
Ključne besede: green vehicle routing problem, alternative fuel vehicles, epsilon-constraint, multi-objective optimization, Pareto optimality
Objavljeno v DKUM: 22.08.2024; Ogledov: 44; Prenosov: 2
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Opis: Small and medium-sized enterprises (SMEs) need to keep pace with large enterprises, thus they need to digitally transform. Since they usually lack resources (budget, knowledge, and time) many countries have their support environment to help SMEs in this endeavor. To be able to ensure the right kinds of support, it is crucial to assess the digital maturity of an enterprise. There are many models and assessment tools for digital maturity, however, they are either theoretical models, partial, vendor oriented, or suited for large enterprises. In this paper, we address the problem of assessing digital maturity for SMEs. For this purpose, we developed a multi-attribute model for assessment of the digital maturity of an SME. We followed the design science research approach, where the multi-attribute model is considered as an IT artifact. Within the design cycle, the decision expert (DEX) methodology of a broader multi-attribute decision making methodologies was applied. The developed model was validated by a group of experts and upgraded according to their feedback and finally evaluated on seven real-life cases. Results show that the model can be used in real business situations.
Ključne besede: digital transformation, digital maturity assessment, multi-attribute model, small and medium-sized enterprises
Objavljeno v DKUM: 07.08.2024; Ogledov: 108; Prenosov: 3
Celotno besedilo (3,07 MB)
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Opis: Network segregation - a critical problem in real-life networks - can reveal the emergence of conflicts or signal an impending collapse of the whole system. However, the strong heterogeneity of such networks and the various definitions for key nodes continue to pose challenges that limit our ability to foresee segregation and to determine the main drivers behind it. In this paper, we show that a multi-agent leader-follower consensus system can be utilized to define a new index, named leadership, to identify key leaders in real-life networks. And then, this paper explores the emergence of network segregation that is driven by these leaders based on the removal or the rewiring of the relations between different nodes in agreement with their contribution distance. We finally show that the observed leaders-driven segregation dynamics reveals the dynamics of heterogeneous attributes that critically influence network structure and its segregation. Thus, this paper provides a theoretical method to study complex social interactions and their roles in network segregation, which ultimately leads to a closed-form explanation for the emergence of imbalanced network structure from an evolutionary perspective.
Ključne besede: complex networks, network segregation, multi-agent leader–follower consensus system, key leaders identification, leader, segregation, social physics
Objavljeno v DKUM: 08.07.2024; Ogledov: 122; Prenosov: 7
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Opis: In this work, a new multi-criteria model for the evaluation of traditional and indigenous horse breeds, the HORQUAL model, was developed by applying the DEX (Decision Expert) method. The idea for this study culminated from brainstorming among researchers who had the importance of conserving traditional and indigenous horse breeds in Slovenia and their universal uses (recreative and sport) in mind. The conservation of native domestic animal breeds is one of the important indicators of sustainable agricultural development in particular countries. Here, the assessment process considered the horse breeds in terms of lifestyle, expectations, requirements and experiences. The development process was based on the multi-criteria decision analysis approach, and it was applied to seven traditional and indigenous Slovenian horse breeds. The horse breeds were classified into four groups of breed ratings according to the chosen criteria. The horse breeds were categorised as follows: “does not correspond to the criteria”, “less correspondence with the criteria”, “corresponds to the criteria” and “completely corresponds to the criteria”. The results of the HORQUAL model clearly show that it is easier and more effective to choose the most suitable breeds for specific purposes (i.e., recreative/sport horses with the potential for breeding along with acceptable costs, favourable temperament and suitable price) as they can easily be analysed or compared with each other, according to the criteria chosen in this paper. The rating by group takes the criteria for the multi-attribute evaluation that were identified by an expert group into account and balances between the assessment of recreational and sports needs for riders and the life expectancy for breeders. Additionally, incorporating the Plus-minus-1 analysis proved to be a useful support tool to analyse the assessments and to further improve horse breeding plans.
Ključne besede: traditional horse breeds, indigenous horse breeds, multi-criteria model, DEX-model
Objavljeno v DKUM: 02.07.2024; Ogledov: 132; Prenosov: 21
Celotno besedilo (5,85 MB)
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