The problem of sustainable transport system development is currently very important and frequently analysed. It concerns promotion of such transport, which is efficient, cost effective and meets the expectations of the society. At the same time, such transport should minimize its negative impact on public health, environment, and economy or urban planning. This paper deals with selected aspects of developing sustainable transport systems and assessing them based on their negative impact on society (amount of pollution and noise emissions). A number of different scenarios for the sustainable transport system development were presented. In addition, a procedure for evaluating these scenarios was proposed (using appropriate evaluation criteria and indicators, including noise and pollutant emissions from road transport). The studies presented in this paper were carried out using the PTV Visum tool and transport models developed in it (e.g. EMITRANSYS or MTAW 2015).
31 March 2019 in Eksploatacja i Niezawodność – Maintenance and Reliability
Effective fleet management is related to the care for their rational use and proper diagnostics. Early detection of potential irregularities enables to prevent failures and carry out transport processes in an undisturbed way. One of the most important components, from the safety point of view, is the braking system. Laboratory tests can be used to determine the durability characteristics of individual components. Individual indications referring to operating conditions would be most desirable. The article, based on a two-year period of testing of a group of Renault vehicles fitted with disc brakes, presents measurement of wearing and tearing the system components (brake discs and brake friction insert) in a function of selected factors, depending on the time and environment in which the transport was carried out. Nonparametric statistical tests were used to analyze the results. Mann-Whitney and Kruskal-Wallis tests were used to verify the hypothesis on the insignificance of differences. Their results were compared with the results of ANOVA variance analysis. The significance of factors influencing the degree of brakes wear was checked. Possible directions of using the results of brake wear measurement for rationalization of transport processes were also indicated. Presented method may also be applied to the evaluation of other components (assemblies, subassemblies, systems) of motor vehicles.
This paper presents the problem of the assessment of the supply chains in the context of their effectiveness. In this paper the concepts of a supply chain and effectiveness were characterized. The supply chain is a structure of entities which are connected with each other by the use of material and financial flows and functional, structural, technological, economic and information dependencies. Entities such as: suppliers, final recipients, entrepreneurs, warehouse facilities, supply centers, logistics operators, carriers, etc. perform material flows from suppliers to recipients. The concept of efficiency, in general terms, refers to economic rationality and means the relationship between the achieved or expected effects and the expenditures incurred. Additionally, indicators of measuring the effectiveness of the supply chain were described. In order to assess the effectiveness of the supply chain the decision model was developed. Optimization is crucial in decision support systems. The development of an appropriate model for mapping the behavior of a real object or system and formulating an optimization task is a necessary activity in effective management. This is even more important if we want to be competitive. Along with the development of decision support systems, as well as the development of systems for data acquisition on the system functioning, which feed optimization models in ever more detailed form, complex decision models are created that take into account many optimization criteria and require a large amount of data. It allows, however, to ensure the sustainable development of the system and simultaneous implementation of its basic tasks. The main aim of this paper is to present the stages and assumptions of the model for assessing the effectiveness of the supply chain. The main data input, constraints of the model, the criteria functions were determined.
In the era of rapidly changing market and consumer needs, there are dynamic changes in the services offered. This also applies to the car fleet market. Currently, the approach to owning a vehicle is changing to other forms such as rental or subscription. Different types of funding are conducive to changes in the fleet management industry. More and more sophis-ticated services are offered for corporate clients, but also private customers. In the context of these changes, the approach to different aspects of vehicle use is also clarified, including what has been noticeable in recent years, increased interest in road safety, environmental issues and most importantly costs of use and possession of the vehicle. This puts high demands on fleet managers who sustainably need to match the structure of their fleets to the needs and capabilities of their customers while taking into account safety and ecology issues. This is a complicated task that requires decision-making assistance. This article addresses the support of the fleet manager decision, taking into account the sustainable management model. The article aimed to develop a model that takes into account the aspects of safety and ecology from the operator-financier the point of view. The result of the article is to provide a decision-making tool for the selection of vehicles and drivers, taking into account their characteristics to accomplish their tasks. The work presents the problem of fleet management, shows the characteristics of different forms of financing and the impact of market trends on the current approach to these problems. The analysis of safety aspects to the possibility of using different methods affecting its level was then presented. Another element of the article is a mathematical model of the problem of resources assignment for tasks. The developed model is universal and can be used for evaluation and optimisation. To this end, the function of the criterion has been formulated, taking into account the aspects of safety, ecology and financial aspects. It also takes into account the randomness of adverse events and the duration of the remaining appropriations in the out-of-order state. This Model can be used for the risk assessment of the driving staff. The developed model was implemented in the Flexsim environment for a computational example for a trading company. Computational experiments have indicated the correctness of the model and its high application potential, as well as further directions of model development to support complex management processes carried out by fleet managers.
The development of railway transport in the current times is very noticeable, it is connected with the growing needs of movement as well as the development of information engineering. The increase in the demand for transport requires the implementation of solutions that increase the efficiency of the transport system. Both long-distance, agglomeration and metro railways can use different systems due to their specificity. Nevertheless, there is a noticeable trend in the development of systems supporting or even replacing the driver by the automation of selected activities. Such systems allow to reduce trains headway and thus increase the capacity of the line. CBTC class systems (Communications-based train control) belong to automatic train systems and are based on wireless transmission. The main purpose of using such systems is to increase the frequency of running trains while maintaining the level of safety. Computers that are on the system equipment record, process and analyse very large amounts of data. An essential element of such systems are recording units. The parameter recorders can be divided into technical and legal ones. However, for CBTC class systems, there is no obligation or requirement to use legal recorders as it is in the case of ETCS. However, it is necessary to use event recorders, and these are subject to the requirements set out in the PN-EN 62625-1: 2014 standard. The recorders are a very important component of safety systems, which is why they were analysed in this article. Both the driver, the vehicle and the infrastructure should be subject of continuous monitoring. The occurrence of an adverse event (not necessarily leading to an incident or accident) should be analysed and used to improve safety procedures. Currently, automatic systems are still developing and we are not able to accurately assess what the causes and effects of certain events may be, which is why data collection and analysis is particularly important. The article presents the general specification of the CBTC system. The parameters and properties of driving recorders should be presented. This article is co-financed by the European Union POIR.01.01.01-00-0276/17
The facility location problem is a popular issue in the literature. The current development of world economies and globalization of the market requires continuous improvement of methods and research in this field. The location of the object determines the time of transport, affects the operational costs of the supply chain, and determines the possible amount of inventory or minimum inventory levels. These are critical issues from the point of view of designing an effective logistics system. The degree of complexity of current decision-making problems requires the construction of mathematical models and support for the decision-maker by optimization and simulation methods. A comprehensive and systemic approach to the problem allows the effective planning of supply chains. The purpose of this article was to study the sensitivity of the warehouse location problem in the supply chain. The solution was obtained based on the methodology developed under the SIMMAG3D project. The article presents the characteristics of the issue of the location of warehouse objects, the mathematical formulation of the solved problem of location and the method of its solution based on the heuristic algorithm using the modification of the Busacker-Gowen method. Then, a supply chain simulation model was developed in the FLEXSIM environment and scenario studies were performed for various input data and model parameters. The analysis and assessment of the solution based on parameters such as utilization of the potential of warehouse objects object were presented. Random change in demand described by Erlang distribution and normal distribution was considered. The analysis showed how the selection of a statistical distribution to describe the input data can affect the shape of the logistics system. The article ends with a summary of considerations and a plan for further research in the use of the simulation environment to support the decision-making process of the location of storage facilities and the functioning of supply chains.