Dejan Dragan, Prof., PhD.
University of Maribor, Faculty of Logistics, Faculty Member
- Industrial Engineering, Logistics, Optimization techniques, Transport Logistics, Supply Chain Management, Stochastic Process, and 87 moreStructural Equation Modeling, Applied Statistics, Time Series Analysis and Forecasting, Corporate Social Responsibility, Mathematical Modelling, Maritime, transport and logistics, Fault Detection, Traffic, Particle Swarm Optimization, Genetic Algorithms, Heuristics, Swarm Intelligence, Metaheuristics (Operations Research), Evolutionary Computation, Ant Colony Optimisation, English for Academic Purposes, Traffic Engineering, Accident analysis and prevention, Sustainable Transportation, Transportation, Traffic Signal Control, Accident analysis, Traffic and Transport Psychology, Intelligent Transportation Systems, Road Safety, Traffic Enforcement, Driver Education, Highway Engineering, Operations Research, Operations Management, Operations research and Optimization, Logistics Management, Supply Chain, Shipping/ Transport Logistics, Transportation Studies, Transport Geography, Reverse Logistics, Transport Planning, Transport Modeling, Exploratory Data Analysis, Causation, Applied Econometrics, Time series analysis, Econometrics, Forecasting and Prediction Tools, Time series Econometrics, Financial Econometrics, Artificial Neural Networks, Future Studies, Futures Studies and Foresight, Maritime Routes, Geographic Information Systems (GIS), Urban Planning, Computer Aided Design, Probability and Mathematical Statistics, Statistics, Multivariate Statistics, Mathematics and Statistics, Forecasting, Statistical Modeling, Prediction-based Decisions & Planning, Predictive Analytics, Time Series Forecasting, Predictive Modeling Using Statistical programs, Econometrics Modeling, Road safety, Public transportation, Economic of Port, Basic and Advanced Statistical/research Methodologies, Advanced Macroeconomics, Economic policy, Maritime Economics and Logistics, Shipping Economics, Ports and Shipping, Port Economics, Shipping, Shipping Management, International Operation In Maritime & Shipping Industry, Shipping policy, Port, shipping and maritime economics, Port Policy, Port economics & finance, Port Planning, Development, and Operations, Port Management, Ports, Transport Economics, Modeling and Inference, Business Analytics; Data Mining; Statistical Learning, Applied mathematics and Modelling, and Descriptive Statisticsedit
- Phd in Electrical EngineeringSpecialist for process modeling, identification and controlAssociate Professor at the Fa... morePhd in Electrical EngineeringSpecialist for process modeling, identification and controlAssociate Professor at the Faculty of logistics, University of MariborSpecialized for Stochastic processes, Statistical modeling, Supply chain management, Transport problems. Optimization of loogistic processesEx-researchr at the Joseph Stefan Institute, Sloveniaedit
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The paper applies a two-stage modelling concept to a gas-gas heat exchanger located in a tyre production plant. Modelling relies on combination of prior knowledge and recorded data. During the identification procedure the estimates of... more
The paper applies a two-stage modelling concept to a gas-gas heat exchanger located in a tyre production plant. Modelling relies on combination of prior knowledge and recorded data. During the identification procedure the estimates of continuous model parameters are calculated by the least squares method with state variable filters (SVF). The main issues of the modelling procedure are stressed. Based on the process model a simple detector is derived. An excerpt of the results obtained on operating records is given.
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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.... more
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 ...
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The paper applies a two-stage modelling concept to a gas-gas heat exchanger located in a tyre production plant. Modelling relies on combination of prior knowledge and recorded data. During the identification procedure the estimates of... more
The paper applies a two-stage modelling concept to a gas-gas heat exchanger located in a tyre production plant. Modelling relies on combination of prior knowledge and recorded data. During the identification procedure the estimates of continuous model parameters are calculated by the least squares method with state variable filters (SVF). The main issues of the modelling procedure are stressed. Based on the process model a simple detector is derived. An excerpt of the results obtained on operating records is given.
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As important as the classical approaches such as Akaikeꞌs AIC information and Bayesian BIC criterion in model-selection mechanism are, they have limitations. As an alternative, a novel modeling design encompasses a two-stage approach... more
As important as the classical approaches such as Akaikeꞌs AIC information and Bayesian BIC criterion in model-selection mechanism are, they have limitations.
As an alternative, a novel modeling design encompasses a two-stage approach that integrates Fuzzy logic and Monte Carlo simulations (MCSs). In the first stage, an entire
family of ARIMA model candidates with the corresponding information-based, residual-based, and statistical criteria is identified. In the second stage, the Mamdani fuzzy
model (MFM) is used to uncover interrelationships hidden among previously obtained models criteria. To access the best forecasting model, the MCSs are also used for
different settings of weights loaded on the fuzzy rules. The obtained model is developed to predict the road freight transport in Slovenia in the context of choosing the most
appropriate electronic toll system. Results show that the mechanism works well when searching for the best model that provides a well-fit to the real data.
As an alternative, a novel modeling design encompasses a two-stage approach that integrates Fuzzy logic and Monte Carlo simulations (MCSs). In the first stage, an entire
family of ARIMA model candidates with the corresponding information-based, residual-based, and statistical criteria is identified. In the second stage, the Mamdani fuzzy
model (MFM) is used to uncover interrelationships hidden among previously obtained models criteria. To access the best forecasting model, the MCSs are also used for
different settings of weights loaded on the fuzzy rules. The obtained model is developed to predict the road freight transport in Slovenia in the context of choosing the most
appropriate electronic toll system. Results show that the mechanism works well when searching for the best model that provides a well-fit to the real data.
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An accurate forecasting system has manifested its role as an enabler in supply chains (SC), which makes the operation possible in a maximally synchronized manner. Its applications have gained the attention of scholars across various... more
An accurate forecasting system has manifested its role as an enabler in supply chains (SC), which makes the operation possible in a maximally synchronized manner. Its applications have gained the attention of scholars across various disciplines such as forecasting in market behavior analysis and tourism industry; material requirement planning in production; transport and logistics foresight in networks and facilities. Seaports, as specific SC members, are not an exception. Accurate forecasting is needed in almost all aspects of the ports’ operation to avoid financial losses related to inappropriate investments and planning. The paper addresses the forecasting of joint demand-supply cargo throughputs in the Adriatic Seaport Koper. The research presents a new forecasting approach, namely, DFA-ARIMAX (Dynamic Factor Analysis-ARIMAX modeling). External economic indicators were screened to obtain useful information using the DFA prior to directing the dynamic factors into the ARIMAX fore...
Research Interests: Computer Science, Economics, Transportation Studies, Prediction, Forecasting, and 15 moreMaritime Policy, Time series Econometrics, Transportation, Statistical Modeling, Forecasting and Prediction Tools, Transportation Management, Stochastic Modeling, Maritime, Port Management, Applied Statistics and Statistical Modelling, Ports, Economic of Port, Advanced Macroeconomic Theory, Routledge, and Time Series Analysis and Forecasting
The Intergovernmental Panel on Climate Change (IPCC) has stated that climate change is a major ongoing process requiring strict restrictive actions on a global level. Also, other environmental challenges like “plasticification” of the... more
The Intergovernmental Panel on Climate Change (IPCC) has stated that climate change is a major ongoing process requiring strict restrictive actions on a global level. Also, other environmental challenges like “plasticification” of the world sea water is a huge and global thread, which should be mitigated. In every fields of human activities actions like recycling, zero CO2 production and responsible operations are expected. However, systems and functions in industries and public sectors have become extremely complicated, which are difficult to make emissions free. Also there are huge differences between countries how responsible production should be understood and organized. Logistics, transportation and supply chain processes in many industries are producing large amounts of emissions. Even if maritime logistics respond only fraction of total global CO2 emissions (round 2,6 %), locally, like in port areas, ships are producing heavily various polluting substances. In large process i...
Electricity supply and demand must match all the time. It is not easy to achieve, because of a highly variable nature of electricity demand and a lack of electricity storing capacities. By introducing electricity from renewable energy... more
Electricity supply and demand must match all the time. It is not easy to achieve, because of a highly variable nature of electricity demand and a lack of electricity storing capacities. By introducing electricity from renewable energy sources, a variability occurs on the supply side as well. As electricity demand keeps rising and renewable energy sources become more and more in use, achieving an electricity supply-demand balance becomes more difficult. As one of the results, new resources are needed for dealing with that raised variability on both sides. In this paper, we consider the idea of using batteries of electric vehicles (EVs) as a resource for balancing electricity supply and demand. The idea implies charging and discharging of EVs batteries for keeping electricity supply and demand balanced. We observe batteries of EVs engaged in that process, as an electricity storage in electricity supply chain (ESC). In light of this, we explain the proposed idea, concepts of its realiz...
The paper addresses the problem of the reconstruction and allocation of delivery positions in the urban area. The aim is to achieve the optimal reorganization of urban freight transport in old town core in the municipality of Celje.... more
The paper addresses the problem of the reconstruction and allocation of delivery positions in the urban area. The aim is to achieve the optimal reorganization of urban freight transport in old town core in the municipality of Celje. Optimal allocation relies on optimization based on the Monte Carlo simulation and represents a first stage of a two-stage optimization approach to re-design the existing urban freight transport. The number of optimal delivery positions is required to be as minimal as possible, which can still assure a maximal service area within the prescribed radius, while keeping the minimal walking distances of delivery personnel between the nearest delivery position and the customerʼs physical location. The main issues of the used heuristic allocation algorithm and the presentation of calculated results are provided. In the near future, the calculated delivery positions are going to be used for the purpose of physical implementation in order to improve the existing d...
Summary. The paper addresses the problem of the reconstruction and allocation of delivery positions in the urban area. The aim is to achieve the optimal reorganization of urban freight transport in old town core in the municipality of... more
Summary. The paper addresses the problem of the reconstruction and allocation of delivery positions in the urban area. The aim is to achieve the optimal reorganization of urban freight transport in old town core in the municipality of Celje. Optimal allocation relies on optimization based on the Monte Carlo simulation and represents a first stage of a two-stage optimization approach to re-design the existing urban freight transport. The number of optimal delivery positions is required to be as minimal as possible, which can still assure a maximal service area within the prescribed radius, while keeping the minimal walking distances of delivery personnel between the nearest delivery position and the customer’s physical location. The main issues of the used heuristic allocation algorithm and the presentation of calculated results are provided. In the near future, the calculated delivery positions are going to be used for the purpose of physical implementation in order to improve the e...
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Ports serve ships and inland with logistic services, first of all. Given the current technology, waste, pollution of air and water and land are difficult to avoid. These problems are additionally difficult to handle, if process... more
Ports serve ships and inland with logistic services, first of all. Given the current technology, waste, pollution of air and water and land are difficult to avoid. These problems are additionally difficult to handle, if process participants fail to behave in a systemic way, i.e., with a (requisitely) holistic approach, based on interdisciplinary creative cooperation on the part of any of process participants and/or their combined teams. The contribution presents a case based on field research in progress, combining observation of a port and use of systems approach in a mathematical way, to study a chance of systemic behavior of a port.
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The urban mobility system is an important factor in social development and must, therefore, be tackled in a way that enables balanced, sustainable development. The purpose of the present work was to introduce a new holistic approach to... more
The urban mobility system is an important factor in social development and must, therefore, be tackled in a way that enables balanced, sustainable development. The purpose of the present work was to introduce a new holistic approach to urban mobility system (UMS) planning, which involves a strategic decision-making process with a broad involvement of various stakeholders. For this purpose, an innovative model was created by synthesizing the focus group (FG) method with the nominal group technique (NGT), SWOT (Strengths, Weaknesses, Opportunities, and Threats) analysis, and the fuzzy analytical hierarchical process (FAHP) method. The fuzzy approach was chosen for its ability to incorporate imprecise and vague information and make a decision-making UMS process more realistic. Accordingly, the objective of the paper was to propose a newly developed model that will (considering the integration of various urban mobility subsystems) enable the detection, identification, and ranking of key...
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Electric load forecasting (ELF) is a vital process in the planning of the electricity industry and plays a crucial role in electric capacity scheduling and power systems management and, therefore, it has attracted increasing academic... more
Electric load forecasting (ELF) is a vital process in the planning of the electricity industry and plays a crucial role in electric capacity scheduling and power systems management and, therefore, it has attracted increasing academic interest. Hence, the accuracy of electric load forecasting has great importance for energy generating capacity scheduling and power system management. This paper presents a review of forecasting methods and models for electricity load. About 45 academic papers have been used for the comparison based on specified criteria such as time frame, inputs, outputs, the scale of the project, and value. The review reveals that despite the relative simplicity of all reviewed models, the regression analysis is still widely used and efficient for long-term forecasting. As for short-term predictions, machine learning or artificial intelligence-based models such as Artificial Neural Networks (ANN), Support Vector Machines (SVM), and Fuzzy logic are favored.
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Forecasting is important in many branches of logistics, including the logistics related to Tourism supply chains. With an increasing inflow of American tourists, planning and forecasting the US tourists’ inflow to Slovenia have gained far... more
Forecasting is important in many branches of logistics, including the logistics related to Tourism supply chains. With an increasing inflow of American tourists, planning and forecasting the US tourists’ inflow to Slovenia have gained far more importance attention amongst scholars and practitioners. This study, therefore, was conducted to forecast the American tourists’ inflow to Slovenia using one of the predictive models based on the exponential smoothing approach, namely Holt-Winters damped additive (HWDA) exponential smoothing method. The model was modified by several improvements, while the obtained results were generalized to other supply chain components. The results show that the forecasting system can predict well the observed inflow, while the methodology used to derive the model might have enriched the plethora of existing practical forecasting approaches in the tourism domain. Benchmarking demonstrates that the proposed model outperforms a competitive ARIMA model and off...
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The paper examines the impact of integration of macroeconomic indicators on the accuracy of container throughput time series forecasting model. For this purpose, a Dynamic factor analysis and AutoRegressive Integrated Moving-Average model... more
The paper examines the impact of integration of macroeconomic indicators on the accuracy of container throughput time series forecasting model. For this purpose, a Dynamic factor analysis and AutoRegressive Integrated Moving-Average model with eXogenous inputs (ARIMAX) are used. Both methodologies are integrated into a novel four-stage heuristic procedure. Firstly, dynamic factors are extracted from external macroeconomic indicators influencing the observed throughput. Secondly, the family of ARIMAX models of different orders is generated based on the derived factors. In the third stage, the diagnostic and goodness-of-fit testing is applied, which includes statistical criteria such as fit performance, information criteria, and parsimony. Finally, the best model is heuristically selected and tested on the real data of the Port of Koper. The results show that by applying macroeconomic indicators into the forecasting model, more accurate future throughput forecasts can be achieved. The...
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The paper addresses the optimal bus stops allocation in the Laško municipality. The goal is to achieve a cost reduction by proper re-designing of a mandatory pupils’ transportation to their schools. The proposed heuristic optimization... more
The paper addresses the optimal bus stops allocation in the Laško municipality. The goal is to achieve a cost reduction by proper re-designing of a mandatory pupils’ transportation to their schools. The proposed heuristic optimization algorithm relies on data clustering and Monte Carlo simulation. The number of bus stops should be minimal possible that still assure a maximal service area, while keeping the minimal walking distances children have to go from their homes to the nearest bus stop. The working mechanism of the proposed algorithm is explained. The latter is driven by three-dimensional GIS data to take into account as much realistic dynamic properties of terrain as possible. The results show that the proposed algorithm achieves an optimal solution with only 37 optimal bus stops covering 94.6 % of all treated pupils despite the diversity and wideness of municipality, as well as the problematic characteristics of terrains’ elevation. The calculated bus stops will represent im...
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Improvements in battery technology make electric vehicles more and more suitable for the use as electricity storages. Many benefits could be achieved by using electric vehicles for storing electricity in their batteries. This paper talks... more
Improvements in battery technology make electric vehicles more and more suitable for the use as electricity storages. Many benefits could be achieved by using electric vehicles for storing electricity in their batteries. This paper talks about the idea of electric vehicles as electricity storages in electric power systems. The idea has a great number of supporters, but also a significant part of the professional community believes that is unfeasible. This paper is not classified in either side and strives to give a realistic picture of this idea. For this purpose, findings from papers published in scientific journals are mainly used. There is also some information from websites, mainly for some technical issues. Partly, the opinions of the authors are present. Specificities of EVs and EPSs that enabled the birth of this idea are explained along with proposed concepts through which the idea can be implemented. Keeping with the vehicle to grid concept, issues about the implementation ...
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The paper addresses an analysis of potential synergies in collaboration between an observed Port in the Mediterranean Sea and Central-European logistic railway-services based company. Both companies have established a strategic... more
The paper addresses an analysis of potential synergies in collaboration between an observed Port in the Mediterranean Sea and Central-European logistic railway-services based company. Both companies have established a strategic partnership. The main motive was cooperation in rail transport, with a particular emphasis on potential synergies that would a rail traffic have brought to a port’s business. For the purpose of synergies valuation under uncertain conditions, a Monte Carlo simulation-based framework with integrated discounted cash flow (DCF) model is applied. The possible values of future synergies are calculated via the DCF model by simultaneously changing values of different uncertain financial parameters at each repetition of a Monte Carlo scenario-playing mechanism. In this process, predicted forecasts of future synergetic throughputs are also used for various types of observed cargo. As it turned out, the generated synergies’ values follow the approximate normal distribut...
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The performance of tourism supply chains depends on the efficiency of all members involved, including the travel agencies. The paper addresses the analysis of relationships between the agencies’ external integration with other supply... more
The performance of tourism supply chains depends on the efficiency of all members involved, including the travel agencies. The paper addresses the analysis of relationships between the agencies’ external integration with other supply chain members on one side, and the efficiency of the agencies on the other. The data envelopment analysis is applied for the estimation of efficiencies, while the structural equation modelling (SEM) is conducted for identification of possible integration impacts on the efficiency. Results show that integration with other supply chain members indeed has some positive impacts on the agencies’ efficiency. Also, the developed SEM model implies that in-depth forms of collaboration would enable more effective exploitation of the identified relations between the integration and efficiency of the agencies. This finding could be an important guideline for the agencies’ management in the sense of achieving more satisfied customers and bigger profits, as well as r...
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The paper deals with studying the relationships between the motorcyclists’ thinking about proper behaviour and their actual behaviour in the traffic. The impact of some control variables, such as riders’ age, experience, driving history,... more
The paper deals with studying the relationships between the motorcyclists’ thinking about proper behaviour and their actual behaviour in the traffic. The impact of some control variables, such as riders’ age, experience, driving history, and engine cubature, on actual behaviour, is also addressed here. For the purpose of research, two additional questionnaires were applied besides the well-known Motorcycle Rider Behaviour Questionnaire (MRBQ). To examine the causal relations between all-important latent factors present in this study, the structural equation model was designed. Exploratory and confirmatory factor analyses were also engaged in the analysis and the statistical modelling process. The results show that the higher awareness about alcohol danger and benefits of protective equipment and helmet can noticeably contribute to the bigger traffic safety. Besides, from the results is evident that the control variables are in most cases also significantly interrelated with the actu...
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The paper addresses the effect of external integration (EI) with transport suppliers on the efficiency of travel agencies in the tourism sector supply chains. The main aim is the comparison of different estimation methods used in the... more
The paper addresses the effect of external integration (EI) with transport suppliers on the efficiency of travel agencies in the tourism sector supply chains. The main aim is the comparison of different estimation methods used in the structural equation modeling (SEM), applied to discover possible relationships between EIs and efficiencies. The latter are calculated by the means of data envelopment analysis (DEA). While designing the structural equation model, the exploratory and confirmatory factor analyses are also used as preliminary statistical procedures. For the estimation of parameters of SEM model, three different methods are explained, analyzed and compared: maximum likelihood (ML) method, Bayesian Markov Chain Monte Carlo (BMCMC) method, and unweighted least squares (ULS) method. The study reveals that all estimation methods calculate comparable estimated parameters. The results also give an evidence of good model fit performance. Besides, the research confirms that the am...
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The paper addresses the problem of optimal bus stop allocation. The aim is to achieve reduction of costs on account of appropriate re-design of the process of obligatory transportation of children from their homes to the corresponding... more
The paper addresses the problem of optimal bus stop allocation. The aim is to achieve reduction of costs on account of appropriate re-design of the process of obligatory transportation of children from their homes to the corresponding schools in the Laško municipality. The proposed algorithm relies on optimization based on the Monte Carlo simulation procedure. The number of calculated bus stops is required to be minimal possible, which can still assure maximal service area within the prescribed radius, while keeping the minimal walking distances pupils have to go across from their homes to the nearest bus stop and vice versa. The main issues of the proposed algorithm are emphasised and the working mechanism is explained. The presentation of calculated results is given and comparison with some other existing algorithms is provided. The positions of the calculated bus stops are going to be used for the purpose of physical bus stops implementation in order to decrease the current trans...
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Purpose – This article aims to explore the impact of supply chain integration on the financial performance of Swedish manufacturing firms. Design/methodology/approach – The literature review provided the foundation for the development of... more
Purpose – This article aims to explore the impact of supply chain integration on the financial performance of Swedish manufacturing firms. Design/methodology/approach – The literature review provided the foundation for the development of the survey instrument and hypotheses for the study. In addition, the survey instrument was tested by the experts in the field and modified before it was sent to the managers in the survey group. Findings – The findings show that supply chain integration at any level is beneficial to the financial well being of the firm. Companies with total supply chain integration reported the highest level of financial performance. Research limitations/implications – Data were collected from Swedish manufacturing firms without regard to the size of the firm. The results show that supply chain integration is beneficial at any level. Practical implications – The findings will assist managers with decisions regarding supply chain integration and its role as a critica...
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An accurate forecasting system has manifested its role as an enabler in supply chains (SC), which makes the operation possible in a maximally synchronized manner. Its applications have gained the attention of scholars across various... more
An accurate forecasting system has manifested its role as an enabler in supply chains (SC), which makes the operation possible in a maximally synchronized manner. Its applications have gained the attention of scholars across various disciplines such as forecasting in market behavior analysis and tourism industry; material requirement planning in production; transport and logistics foresight in networks and facilities. Seaports, as specific SC members, are not an exception. Accurate forecasting is needed in almost all aspects of the ports' operation to avoid financial losses related to inappropriate investments and planning. The paper addresses the forecasting of joint demand-supply cargo throughputs in the Adriatic Seaport Koper. The research presents a new forecasting approach, namely, DFA-ARIMAX (Dynamic Factor Analysis-ARIMAX modeling). External economic indicators were screened to obtain useful information using the DFA prior to directing the dynamic factors into the ARIMAX forecasting model. The principal component regression and Monte Carlo framework were included to identify indicators that are unique to the port. Findings revealed that a forecasting system by its enriched capabilities to predict the observed throughputs could be seen as Functional Decision Support System. The benchmarking shows that proposed models outperform competitive models. Practical implications are discussed in detail.
Research Interests: Transport Logistics, Prediction, Forecasting, Maritime Policy, Transportation, and 10 moreStatistical Modeling, Forecasting and Prediction Tools, Transportation Management, Port Management, Applied Statistics and Statistical Modelling, Economic of Port, Advanced Macroeconomic Theory, Port, shipping and maritime economics, Port economics, policy and management, and Time Series Analysis and Forecasting
ABSTRACT Transport accounts for 26% of global carbon dioxide emissions. The need to reduce greenhouse gas emissions, especially carbon dioxide, is thus becoming increasingly urgent and several approaches have been adopted to achieve this... more
ABSTRACT Transport accounts for 26% of global carbon dioxide emissions. The need to reduce greenhouse gas emissions, especially carbon dioxide, is thus becoming increasingly urgent and several approaches have been adopted to achieve this goal. Alternative sustainable technologies form one possible solution, and changes in driving styles could also contribute to a reduction in emissions. An alternative interesting approach is to reduce vehicle miles travelled. In this paper, the concept of vehicle miles travelled reduction based on a heuristic optimisation approach and geographical information system technology is introduced. The suitability of the concept was tested with the school bus routing problem. Working mechanisms of the adopted optimisation algorithms are explained. The results show that optimisation of bus stops, bus routes and driving schedules could significantly reduce the amount of vehicle miles travelled and, consequently, carbon dioxide emissions.
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Sustainable engineering is very important for logistics systems. Nowadays, sustainable warehouse management is a key factor in market success. Workforce fluctuation and inverting the number of customers’ demands make a lot of problems in... more
Sustainable engineering is very important for logistics systems. Nowadays, sustainable warehouse management is a key factor in market success. Workforce fluctuation and inverting the number of customers’ demands make a lot of problems in distribution warehouses. This study addresses a sustainable approach for the workforce scheduling problem recognized in a real distribution warehouse. The problem arises from the high variability of demand for workers over one workday, which causes workforce surplus in some periods of the workday and shortages in others. Engineering managers of the distribution warehouse already use different full-time and part-time shifts, and schedule workers on different activities, but they still have significant workforce surpluses or shortages in some periods. This study proposes the scheduling of activities’ execution together with workers to face that variability and decrease the cost of the workforce. This idea comes from the fact that some activities in a ...
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ABSTRACT One of the key issues in modelling for condition monitoring is how to accommodate the level of detail of the model description in order to suit the diagnostic requirements. The paper addresses a two-stage modelling concept, which... more
ABSTRACT One of the key issues in modelling for condition monitoring is how to accommodate the level of detail of the model description in order to suit the diagnostic requirements. The paper addresses a two-stage modelling concept, which tends to result in highly accurate grey models by combining prior knowledge and recorded data. A class of continuous-time models linear in parameters is treated. An idea related to the generation of candidate model structures for a class of distributed parameter systems is suggested. It is shown that the resulting models take minimal parameterisation for a given quality of fit. To calculate bias-free estimates of model parameters, an almost straightforward instrumental variables approach (IVA) combined with data pre-filtering is employed. It is shown that the estimates produced by IVA are largely invariant of the bandwidth of the pre-filters (state variable filters). This greatly reduces the overall modelling effort and makes the whole concept applicable even to less experienced users. The concept is used to design a diagnostic system for the heat transfer process in a tyre production plant. An excerpt of the results obtained in operating records is given.
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Providing optimised routing solutions have always been a priority to maximally decrease the cost of school transport. This study aims to achieve the reduction of existing costs, generated while processing the far-free transportation of... more
Providing optimised routing solutions have always been a priority to maximally decrease the cost of school transport. This study aims to achieve the reduction of existing costs, generated while processing the far-free transportation of eligible pupil commuters. An optimisation problem comprises minimisation of the vehicles’ costs and total travel time for all pupils. To solve this problem, the proposed heuristic algorithm is developed based on route planning dependent on changes in schools’ starting times so that the vehicles can visit a bigger number of schools within one route. The algorithm has been applied for a case of the observed municipality in the EU region and successfully runs for already five years. This study differs from the others as it deploys two-mechanism procedures including (a) identification of eligible pupil commuters prior to assigning them to the bus stops and (b) figuring out the optimal assignment of beginning/ending times of lessons for selected schools that would be simultaneously obtained with the optimal driving routes and fleet. The results show that a total daily mileage of all vehicles was for almost 300 kilometres lowered compared to the previous un-optimised situation, while the total number of vehicles was reduced for almost 50%.
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V članku primerjamo dvodimezionalni (2D) in tridimenzionalni (3D) model usmerjanja šolskih vozil na primeru občine Laško z vidika dolžine prepeljanih kilometrov in porabljenega potovalnega časa. Pri 3D modelu je cestna mreža položena... more
V članku primerjamo dvodimezionalni (2D) in tridimenzionalni (3D) model usmerjanja šolskih vozil na primeru občine Laško z vidika dolžine prepeljanih kilometrov in porabljenega potovalnega časa. Pri 3D modelu je cestna mreža položena preko digitalnega modela višin 12,5 metrov, kar daje modelu večjo podobnost z realnostjo. Za uspešno rešitev je v obeh modelih potrebnih 23 kombijev. V 3D modelu je dolžina vseh opravljenih poti za 45,58 kilometrov večja kot v 2D modelu, skupni potovalni čas pa daljši za 1 uro in 14 minut. Ugotovljena razlika je pomembna pri odločanju za izbiro enega ali drugega modela pri reševanju problemov usmerjanja šolskih vozil.
ABSTRACT The paper addresses a heuristic-based optimization approach for the transportation of pupils in the Municipality of Žalec, Slovenia. The aim is to achieve the reduction of existing costs, generated while processing the far free... more
ABSTRACT The paper addresses a heuristic-based optimization approach for the transportation of pupils in the Municipality of Žalec, Slovenia. The aim is to achieve the reduction of existing costs, generated while processing the far free transportation of eligible pupil commuters. The proposed algorithm relies on two main stages. In the first stage it is identified, who the eligible pupil commuters really are, and after that they are assigned to the corresponding bus stops. In the second stage, the optimal beginning/ending times of lessons for each selected school are firstly found in the process of school bell time adjustment, and then the determination of optimal driving routes and optimal driving fleet is conducted. Due to the nature of solving of the problem in this work, we can classify it into the family of well-known School Bus Routing Problems (SBRP). The results show that the total average daily mileage of all vehicles would be even for almost 300 km lower in the case of applying the optimal transportation policy. In addition, the total number of transport vehicles would be significantly lowered, if our optimization approach had been applied into the real every day practice. The municipality authorities recognized the significant practical value of the results and were very interested to conduct the proposed optimization policy into the reality as soon as possible.
The goal of the study was to investigate if the drivers behave in the same way when they are driving a motorcycle or a car. For this purpose, the Motorcycle Rider Behaviour Questionnaire and Driver Behaviour Questionnaire were conducted... more
The goal of the study was to investigate if the drivers behave in the same way when they are driving a motorcycle or a car. For this purpose, the Motorcycle Rider Behaviour Questionnaire and Driver Behaviour Questionnaire were conducted among the same drivers population. Items of questionnaires were used to develop a structural equation model with two factors, one for the motorcyclist’s behaviour, and the other for the car driver’s behaviour. Exploratory and confirmatory factor analyses were also applied in this study. Results revealed a certain difference in driving behaviour. The principal reason lies probably in mental consciousness that the risk-taking driving of a motorbike can result in much more catastrophic consequences than when driving a car. The drivers also pointed out this kind of thinking and the developed model has statistically confirmed the behavioural differences. The implications of these findings are also argued in relation to the validation of the appropriatenes...
My primary research areas: Statistics, statistical and stochastic modeling; Time series modeling, analysis, and forecasting in different fields; Structural equation modeling in the fields of management, traffic, and supply chains;... more
My primary research areas: Statistics, statistical and stochastic modeling; Time series modeling, analysis, and forecasting in different fields; Structural equation modeling in the fields of management, traffic, and supply chains; Econometrics; Corporate finance and the theory of investments and valuations of firms; Maritime Economics; Transportation economics, optimization and engineering; Traffic safety and engineering; Other fields of logistics and optimization/control of logistics/transport systems; Development of heuristic optimization methods, metaheuristics, and combinatorial optimization on the networks combined with the GIS systems; Simulation and modeling in the Supply chain management; Research on solving the inventory-routing-allocation problems in logistics; Research about emission models related to a GHG gasses' pollution generated by the road and vessels' transport; Model-based Fault detection of industrial processes; Mathematical research to quantify a possible social irresponsibility of the companies; Statistical modeling in the field of intelligence, security, and counter-terrorist research, respectively, and in the field of humanitarian logistics and international trade; Development of the decision-support systems in various fields (e.g. the Urban Mobilility Systems).
University of Maribor uses Simio href="https://www.simio.com/">simulation software under a grant from Simio LLC href="https://www.simio.com/">www.simio.com
University of Maribor uses Simio href="https://www.simio.com/">simulation software under a grant from Simio LLC href="https://www.simio.com/">www.simio.com