Konrad Lewczuk

Vehicle routing in an urban area: environmental and technological determinants

This paper discusses selected environmental and technological issues of routing freight vehicles in urban areas. The conditions of organizing distribution minimizing not only realization time but also the emission of harmful components of exhaust gases are described. Time-dependant traffic conditions characteristic for densely populated urban areas are defined and discussed according to ecological aspects. Theoretical information about CO2 emission in urban conditions are gathered and used to formulate the base of a mathematical model of a Time-Dependant Vehicle Routing Problem with emission criteria function, as a version of the Capacitated Vehicle Routing Problem. The model comprises selected characteristics of urban transport infrastructure such as distances, speed limits, zones, or the effect of rush hours. It allows considering different types of vehicles according to the task requirements and emission characteristics, and changing traffic conditions. The model is implemented onto a representation of a real transport network and solved for given data with two-step heuristics based on a modified A-star algorithm and genetic programming. Appropriate results, future research directions and other potential uses are presented and discussed.

Implementation of the model of proecological transport system

Paper presents assumptions to build simulation model allowing computational experimentation and inference on impact of various factors on transport modal split and the impact that transport has on environment. It presents a general mathematical model of environmentally friendly transport system and characterizes particular elements of this model. The structure of transport network is mapped with a graph. The characteristics describing elements of this structure, vehicles, and characteristics of harmful compounds emission are given. Model will be implemented in PTV VISUM environment – a tool supporting planning of transport processes as well as analysis and designing of transport systems. The model of proecological transport system developed in PTV VISUM will consist of model of demand for both passenger and freight transport, and model of transport network cooperating with various means of transport. Road and rail vehicles for passenger and freight transport are characterized and divided into groups according to type of fuel and harmful emission. The demand for transport services and emission of exhaust gases components are reflected in model of proecological transport system of Poland. The last part of paper presents a sample of preliminary research on estimating emission from particular type of vehicle.

EXHAUST EMISSION MEASUREMENTS IN THE DEVELOPMENT OF SUSTAINABLE ROAD TRANSPORT

Economic development of nations leads to a higher living comfort of the society. Rich societies want to move safely and independently and demand immediate availability of purchased goods or – in the case of Internet shopping – delivery in the shortest possible time. Such an approach facilitates a continuous growth in the number of road vehicles. At the current level of technology advancement, an increasing number of vehicles results in a growth of the consumption of fossil fuels, which entails increased exhaust emissions and that, in turn, has a negative impact on the health of the living organisms. Another negative consequence of an increased number of vehicles (increased road congestion) is the emission of noise. This problem is particularly significant in large agglomerations where people are surrounded by moving vehicles. This paper presents the extent of influence of the automotive industry on the natural environment and the extent of changes in vehicle design and organization of road infrastructure that were instituted to reduce the transport’s environmental burden. The further part of the paper presents a definition of the development of sustainable transport, its advantages and hurdles that we may encounter when modernizing a transport system. Subsequently in the paper, the measurements under actual vehicle operating conditions were described together with the possibilities of analysis of the research results and the advantages resulting from such an approach during the assessment of the impact of the automotive industry on the natural environment.

The concept of genetic programming in organizing internal transport processes

The paper presents proposition of using genetic algorithm to support organization of internal transport processes in logistics facilities. The organization of internal transport can be done through solving optimization task of scheduling internal transport process with allocation of human resources and equipment to the tasks. Internal transport process was defined and discussed as an object of organization. Precise methods of solving proposed optimization task were unable to give useful solutions according to the computational complexity of the problem, so heuristic genetic algorithm was proposed. The possible structures of chromosome representing feasible solutions, methods of generating initial population, base genetic operators: selection and inheritance, crossover, mutation and fixing of individuals were described. The main implementation difficulties, computational experiments and the scope of application of the algorithm were discussed.

Transportation Services Costs Allocation for the Delivery System

This paper presents a method of allocation transportation services costs to the carriers clients. Method is based on determining replacement costs for two cost-driven elements: amount of pallet-kilometers and time consumed for services realization in purpose of using it to weight real costs for finding actual share of clients in total costs.

Technical and organizational conditions of designing warehouses with different functional structures

The article presents a discussion on designing warehouse facilities and processes as a part of logistics systems. The main technical and organizational conditions of designing and modelling warehouses as well as internal and external factors influencing warehouse operation are presented. The stochastic nature of these factors is indicated. In the next part, a six-piece model of the warehouse facility is presented and discussed. The model embraces spatial conditions of the object and hierarchical division of space for functional reasons, internal transport subsystem with its resources, warehousing process and a set of organizational assumptions for modelling and designing. Typical elements of warehousing process, classification of warehouses due to their functions and tasks, functional classification of warehouse facilities, technological and organizational conditions of designing warehouse facilities, warehouse designing loop, the determinants of warehouse designing, the elements of the model of a warehouse, functional structure of a warehouse, warehousing process, internal transport system, logistics task, work organization rules and informatics system are presented in the paper.

Decision making strategies for warehouse operations

The paper presents issues related to design and organization of warehouse processes. Draws attention to problems of modelling logistics facilities and processes occurring in them. Paper also points out the essence of correct operation of warehouses and associated with this risks for supply chain. Warehouse processes have been properly defined and divided into smaller components, like: phases of process, activities, sets of procedures, procedures or working movements. Paper presents various possible configurations of warehouse processes, which were named as warehouse strategies. Warehouse process strategy is a part of warehousing. It determines the sequence of warehouse operations. These operations are related to internal transport, cargo form transformation and cargo buffering. In paper it is noted that the warehouse strategy depends on the several technical and organizational factors and is associated with a certain probability. This probability can be estimated based on data analysis concerning logistics processes in the specified warehouse facility. As shown in case study, appropriate selection of warehouse strategies determines possibility of fulfilling customer order in time and costs that are acceptable for him.

The method for evaluation of efficiency of the concept of centrally managed distribution in cities

AbstractThe paper describes proecological solution dedicated for organizing logistics services in urban areas. Proposed solution is based on cross-docking processes combined with consolidation centres. Authors proposed new method of estimating economic and social benefits from implementing centrally managed cooperation of logistics operators using common city consolidation hubs. Developed mathematical model bases on Vehicle Routing Problem (VRP) with vehicles of different types, limited loading capacities and multiply depots characterized by limited throughput. Proposed approach was supported by case study of integration of distribution processes in Warsaw (Poland) performed by three medium-size logistics operators. The central management of distribution was investigated in variants assuming using existing warehouses and with new configuration of logistics network developed with using SIMMAG 3D tools. As it was proved for analysed case, total costs of distribution in the city after implementation of centr...

Dependability issues in designing warehouse facilities and their functional areas / Zagadnienia niezawodności w projektowaniu magazynów i ich obszarów funkcjonalnych magazynów

Abstract The dependability of warehouse facility results from dependability and reliability of its functional areas and effects on the reliability of entire supply chain. The elements of dependability of warehouse facilities should be taken into account at the design stage, but this is difficult because of the complexity of these systems and the variability of qualitative and quantitative structure of material flows at the inputs and outputs. Currently used procedures in warehouse designing include the dependability as criteria to assess the solutions in simplistic terms. The paper presents attempts to systematize basic research issues related to the dependability of warehouses as elements of supply chains on one hand, and technical systems on the other. This will allow specifying reliability measures possible to determine in relation to typical parameters of warehouse facility. This will lead to generalization of the model assessing the reliability of the warehousing processes. Streszczenie Niezawodność obiektu magazynowego wynika z niezawodności jego obszarów funkcjonalnych i wpływa na niezawodność całego łańcucha dostaw. Aspekty niezawodnościowe pracy magazynu powinny być uwzględniane na etapie projektu, jednakże jest to trudne ze względu na złożoność tych systemów oraz zmienność struktury jakościowej i ilościowej strumieni materiałów na wejściach. Aktualnie stosowane procedury projektowania obiektów magazynowych uwzględniają klasyczne miary niezawodności jako kryterium oceny rozwiązania jedynie w dużym uproszczeniu. W artykule podjęto próbę usystematyzowania podstawowych zagadnień badawczych związanych z niezawodnością magazynów będących elementami łańcuchów dostaw, a jednocześnie obiektami technicznymi. Na tej podstawie możliwe będzie wyspecyfikowanie miar niezawodności możliwych do określenia w oparciu o typowe parametry obiektu magazynowego. Pozwoli to na uogólnienie modelu do oceny niezawodności procesu magazynowego.

Computer Aided Implementation of Logistics Processes – Selected Aspects

The paper presents selected aspects of the application of information technology to support the implementation of logistics processes. The general discussion about optimization logistics processes precedes basics of designing procedure for logistics systems of different scale which are the foundation for three examples of applications tailored for micro-, and mezo-scale logistics systems. Applications are presented and discussed as tools to optimize logistics processes in aspect of their simultaneous usage to create advanced and comprehensive planning tools. Presented tools enable not only the design of selected elements of the logistics system but also allow assessing their effectiveness. An example of the possible use of applications LogMND to support shaping and dimensioning of point and linear logistic network elements and SCHED to support designing warehousing processes are given.