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Abstract: Background: City logistics is a critical component of urban economic development, as it optimizes supply chains, enhances customer satisfaction through reliable deliveries, and minimizes environmental impacts in densely populated areas. This field addresses various challenges, including traffic congestion, environmental concerns, noise pollution, and the crucial need for timely deliveries. Routing and scheduling are central to logistics operations, with modern software integrating time windows to meet precise scheduling demands driven by detailed customer requirements and operational efficiencies. Furthermore, advanced vehicle routing models now effectively simulate real-world factors such as traffic congestion, stochastic travel times, and dynamic product demands. Purpose: This paper aims to develop an algorithm that addresses the routing decisions. Our approach extends to the time dimension, considering travel times and customer service times within predefined time windows. Study design/methodology/approach: The proposed algorithm is structured to execute in iterative phases, aiming to optimize key logistical objectives. In order to generate competitive solutions, we seek to minimize the number of vehicles utilized and overall travel costs. The evaluation of solution space was conducted via Simulated Annealing. Findings/conclusions: The performance of the proposed algorithm, evaluated using the Gehring and Homberger benchmark instances for 200 customers, demonstrates its effectiveness. The algorithm successfully meets the target number of vehicles required, and the associated travel costs are on average within 1% of the best solutions reported in the relevant literature. Limitations/future research: Given the ongoing need for timely solutions from decision-makers, future research endeavors will focus on enhancing the computational efficiency of the algorithm. Additionally, incorporating more time-related features, such as stochastic travel times, could further improve the algorithm's real-time applicability.
Keywords: city logistics, vehicle routing, simulated annealing, time windows, scheduling
Published in DKUM: 27.03.2025; Views: 0; Downloads: 1
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Abstract: A new approach for spatial modelling of transport mode choice is presented in the paper. The approach tackles the problem by considering the trade-off between subjective and objective factors. To obtain mode Preference Rates (PRs) based on subjective factors, the Analytic Hierarchy Process (AHP) method is applied. The objective factors are expressed with the journey time from any point in the map to destination according to the available transport mode choice on the specific connection. The results are presented as PRs of individual transport modes. The model is validated on the con-ducted the survey, with students of Vienna University of Economics and Business (WU) as a target audience. Members of different target groups (age, national, employment) decide differently regarding the transport choice, so it is better to analyse them separately. The presented model can be used for the city transport planning in any urban area. It can help promote the sustainable modes of transport in the areas that are less adjusted in sustainable manner.
Keywords: transport mode choice, passenger transport, spatial modelling, city transport planning, city mobility, urban logistics, ergonomics, AHP, decision-making policy, GIS, students, objective and subjective factors, transport management
Published in DKUM: 10.12.2024; Views: 0; Downloads: 7
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Abstract: Black carbon is one of the riskiest particle matter pollutants that is harmful to human health. Although it has been increasingly investigated, factors that depend on black carbon distribution and concentration are still insufficiently researched. Variables, such as traffic density, wind speeds, and ground levels can lead to substantial variations of black carbon concentrations and potential exposure, which is even riskier for people living in less-airy sites. Therefore, this paper "fills the gaps" by studying black carbon distribution variations, concentrations, and oscillations, with special emphasis on traffic density and road segments, at multiple locations, in a small city located in a basin, with frequent temperature inversions and infrequent low wind speeds. As wind speed has a significant impact on black carbon concentration trends, it is critical to present how low wind speeds influence black carbon dispersion in a basin city, and how black carbon is dependent on traffic density. Our results revealed that when the wind reached speeds of 1 ms-1 , black carbon concentrations actually increased. In lengthy wind periods, when wind speeds reached 2 or 3 ms-1 , black carbon concentrations decreased during rush hour and in the time of severe winter biomass burning. By observing the results, it could be concluded that black carbon persists longer in higher altitudes than near ground level. Black carbon concentration oscillations were also seen as more pronounced on main roads with higher traffic density. The more the traffic decreases and becomes steady, the more black carbon concentrations oscillate.
Keywords: black carbon, black carbon concentration, traffic pollution, air pollution, wind, traffic density, logistics, basin city
Published in DKUM: 20.08.2024; Views: 44; Downloads: 9
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Abstract: The aim of this paper is to show the spectrum of problems associated with the growing importance of cities in the context of rapidly occurring processes of urbanization. Therefore the following issues are included: the concept of smart cities, which are a combination of the intelligent use of information systems allowing for active management of the various areas of urban activity with the potential of institutions, companies and the active involvement and creative people; transport problems and the use of new technologies. Particular attention will be given to both, the issue of transport congestion as the strongest factor affecting the quality of life of residents and to the role of social capital in the creation of sustainable development. To exemplify the result of the cooperation between southern Polish communities there will be presented a case of the introducing process of the Silesian Card of Public Services with a wide range of its functionality.
Keywords: city logistics, sustainable development, smart cities, city development, urbanization
Published in DKUM: 17.11.2017; Views: 2005; Downloads: 288
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Abstract: Master thesis has it's fundamentals in the use of theoretical methods for modeling purposes on the case study of city logistics and modeling of traffic flow and transportation problem on the city of Győr, Hungary. In practical part, we made a measurements of traffic flow on street sections in the city of Győr. With Android application, we gathered necessary data. We also prepared maps of the route sections of the city from various entry points to the final, destination point. Purpose of our thesis was finding the optimal solution for the delivery to the city centre with the use of strategic games. Final step was a preparation of mathematical model in Mathematica programming environment, which gave us results, but most important is the development of the model itself. Model is constructed in a way that can be use in various possible situations and on different city centres or case studies.
Keywords: city logistics, strategic games, Nash Equilibrium, modeling of traffic flow
Published in DKUM: 17.10.2013; Views: 2189; Downloads: 141
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