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Wybrane zagadnienia kształtowania systemu dystrybucji ładunków z wykorzystaniem rowerów towarowych wewnątrz aglomeracji miejskiej

Starczewski Jakub

Transport Miejski i Regionalny

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2023

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nr 1

3--8

PL

Artykuł podejmuje problematykę poprawy efektywności dostaw ładunków w zabytkowych centrach dużych miast i aglomeracji przy wykorzystaniu rowerów towarowych. Stanowi on opis wybranych zagadnień wchodzących w zakres rozprawy doktorskiej autora [1]. W artykule zaprezentowano model matematyczny systemu dostaw, w ramach którego zidentyfikowane zostały następujące elementy: kryterium oceny efektywności systemu, model popytu na dostawę ładunków, metody trasowania pojazdów oraz metody wyboru lokalizacji punktów przeładunkowych. Wszystkie elementy zostały scharakteryzowane w późniejszych częściach tekstu. Zaproponowano podejście do ewaluacji systemów dostaw ładunków poprzez identyfikację wskaźnika oceny efektywności uwzględniającego wymiar ekonomiczny procesu technologicznego oraz założenia strategii zrównoważonego rozwoju. Sformalizowano sposób obliczenia poszczególnych składowych wskaźnika oceny efektywności. Część badawcza obejmuje charakteryzację dwóch eksperymentów symulacyjnych przeprowadzonych za pomocą specjalnie stworzonego oprogramowania. Pierwszy z nich zrealizowano przy wykorzystaniu zaproponowanej metody analizy statystycznej wskaźnika oceny efektywności oraz heurystycznej metody środka ciężkości. Dotyczył on wyznaczenia lokalizacji punktu przeładunkowego na potrzeby rowerowego systemu dystrybucji. Drugi natomiast polegał na ocenie trzech metod marszrutyzacji (algorytmu oszczędzania Clarke’a–Wrighta, symulowanego wyżarzania i algorytmu genetycznego) w kontekście wartości przyjętego wskaźnika oceny efektywności. Jego przebieg odbywał się zgodnie z opracowanym planem eksperymentu pełno-czynnikowego, uwzględniającego zmienność popytu na przewozy ładunków. Całość zakończono wnioskami płynącymi z zaprezentowanej pracy badawczej, a także zaproponowano dalsze kierunki badań i rozwoju tematyki.

EN

The article deals with the issue of improving the efficiency of cargo delivery in agglomerations, using cargo bikes. It is a description of selected issues falling within the scope of the dissertation with the same title. The article presents a mathematical model of the delivery system, including elements that have been identified: the criterion for evaluating the system’s effectiveness, the model of demand for the cargo delivery, the methods of vehicle routing and the methods of choosing the reloading points’ location. An approach to the evaluation of cargo delivery systems w as proposed by identifying an efficiency assessment indicator, which takes into account the economic dimension of the technological process and the assumptions of the sustainable development strategy. The research includes the characteristics of two simulation experiments. First was conducted using the proposed method of statistical analysis of the effectiveness evaluation indicator and the heuristic method – the center of gravity method. Second was consisted in evaluating three vehicle routing methods. The article was summed up with conclusions from the presented research. Moreover, further directions of research and development of the subject were proposed.

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A communication network routing problem: Modeling and optimization using non-cooperative game theory

Dubey Sapana P., Kedar Ganesh D., Ghate Suresh H.

International Journal of Applied Mathematics and Computer Science

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2021

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Vol. 31, no. 1

155--164

EN

We consider a communication network routing problem wherein a number of users need to efficiently transmit their throughput demand in the form of data packets (incurring less cost and less delay) through one or more links. Using the game theoretic perspective, we propose a dynamic model which ensures unhindered transmission of data even in the case where the capacity of the link is exceeded. The model incorporates a mechanism in which users are appropriately punished (with additional cost) when the total data to be transmitted exceeds the capacity of the link. The model has multiple Nash equilibrium points. To arrive at rational strategies, we introduce the concept of focal points and get what is termed focal Nash equilibrium (FNE) points for the model. We further introduce the concept of preferred focal Nash equilibrium (PFNE) points and find their relation with the Pareto optimal solution for the model.

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Selected multicriteria shortest path problems: An analysis of complexity, models and adaptation of standard algorithms

Tarapata Z.

International Journal of Applied Mathematics and Computer Science

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2007

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Vol. 17, no 2

269-287

EN

The paper presents selected multicriteria (multiobjective) approaches to shortest path problems. A classification of multiobjective shortest path (MOSP) problems is given. Different models of MOSP problems are discussed in detail. Methods of solving the formulated optimization problems are presented. An analysis of the complexity of the presented methods and ways of adapting of classical algorithms for solving multiobjective shortest path problems are described. A comparison of the effectiveness of solving selected MOSP problems defined as mathematical programming problems (using the CPLEX 7.0 solver) and multi-weighted graph problems (using modified Dijkstra’s algorithm) is given. Experimental results of using the presented methods for multicriteria path selection in a terrain-based grid network are given.

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Overview of shufflenet and its variations in lightwave networks

Bhattacharya U., Ghassemlooy Z.

Foundations of Computing and Decision Sciences

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2006

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Vol. 31, No. 3-4

193-220

EN

This paper outlines a review of application of ShuffleNet and its variations as logical topologies in lightwave networks and tries to consolidate the results reported so far. ShuffleNet, a very popular interconnection structure, proposed by Acampora as a logical topology in multihop optical networks has been generalized later with a view to obtaining a network topology for optimal throughput. Bilayered ShuffleNet has been designed to reduce the diameter and average hop distance compared to ShuffleNet. But, absence of any simple bidirectional self-routing scheme in Bilayered ShuffleNet led to design SW-Banyan network, an isornorphic equivalent of the ShuffleNet offering a convenient layout. Bi-directional ShuffleNet facilitates lesser hopping distance between any source-destination pair compared to ShuffleNet. Multistar Implementation of expandable ShuffleNet and GEMNet have been developed to insert flexibility in the structure of ShuffleNet.

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A normative proposal for obtaining a suitable multiattribute generalized cost in routing problems

Lopez F., Fernandez E.

Foundations of Computing and Decision Sciences

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2002

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Vol. 27, No. 1

17-26

EN

Up to now, the routing problem with physical planning, (choosing the best route linking each pair of adjacent nodes belonging to a road network), has been solved only using an imprecise heuristic approach. In this paper we present a normative method which uses some proxy variables for modeling the main attributes, and is based on a set of rational axioms which provides a good framework for clearing Decision Maker's preferences and beliefs, following the paradigm of Decision Analysis. This method has been successfully applied in practical decision making.

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On the effectiveness of column generation for time constrained routing problems

Haouari M.

Foundations of Computing and Decision Sciences

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2001

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Vol. 26, No. 3

215-224

EN

This paper describes how column generation techniques can be used to solve to optimality the Fleet Size and Mix Vehicle Routing Problem with Time Windows (FSMVRPTW). This problem is practically important and computationally challenging. It involves the joint optimization of the fleet mix and the set of delivery routes. The main contribution of this paper is to show, by an appropriate graph transformation, that the approach previously developed for the classical VRPTW, and based upon the use of the set partitioning formulation and the column generation techniques yields very good results for the FSMVRPTW. The proposed approach is the first optimization algorithm developed so far for the FSMVRPTW. Computational results are reported on a set of test problems with up to 80 customers.