Forecasting is one of the logistics activities and a sales forecast is the starting point for the elaboration of business plans. Forecast accuracy affects the business outcomes and ultimately may significantly affect the economic stability of the company. The accuracy of the prediction depends on the suitability of the use of forecasting methods, experience, quality of input data, time period and other factors. The input data are usually not deterministic but they are often of random nature. They are affected by uncertainties of the market environment, and many other factors. Taking into account the input data uncertainty, the forecast error can by reduced. This article deals with the use of the software tool for incorporating data uncertainty into forecasting. Proposals are presented of a forecasting approach and simulation of the impact of uncertain input parameters to the target forecasted value by this case study model. The statistical analysis and risk analysis of the forecast results is carried out including sensitivity analysis and variables impact analysis.
This article is devoted to modelling of the extracted raw material removal from a mining area to the entry point for the next technological process. Two approaches were chosen for the process modelling. The first approach is regarded to traffic modelling by using available mathematical equations, based on capacity conversion and calculation of loading equipment efficiency. The second approach of modelling is computer simulation within the simulation system ExtendSim8. The modelling of the transport system and the determination of its efficiency were performed at the same conditions. The examined transport system was consisted of two lorries and one loader. The article presents the results of calculations and the results of simulation experiments, which also verified the results obtained by calculations. Calculations of the transport system performance and simulation experiments were performed for two time periods, for a time of 1 h and 6 h during a shift from three different loading places, which were 500, 1100 and 1450 m away from a place of unloading. The results obtained by both approaches are comparable. The main contribution, novelty, of this article is the modelling of the process in a quarry operation (loading and removal of mineral resources) not only on the basis of available mathematical formulas but also the application of simulation in the simulation tool EXTENDSim8, performing simulation experiments for specified conditions and their comparison with calculated values. Simulation is a suitable tool for determining and subsequently planning of the performance of both existing and projected transport systems.
Demand forecasting is very often used in production planning, especially, when a manufacturer needs in a longer production cycle to respond flexibly to market demands. Production based on longer-term forecasts means bearing the risk of forecast unreliability in the form of finished product inventory deficit or excess. The use of computer simulation allows us to improve the planning process and optimise the plan for the intended goal. This paper presents the use of quantitative forecasting and computer simulations to create the production plan. Two approaches to production plan creation are demonstrated in a model case study. Products are characterized by varying demand and are produced on a single production line in continuous operation. The first approach uses ARIMA(2,0,2) (Auto-Regressive Integrated Moving Average) prognostic method selected as the most reliable method based on MAPE (Mean Absolute Percent Error). The second method applies Monte Carlo simulations and optimisation. The aim of the plan optimisation is minimisation the total costs connected with line rebuilding and storage of products. The comparison of the two approaches shows that planning using computer simulations and optimisation leads to lower total costs.
The warehouse process, as one of many logistics processes, currently holds an irreplaceable position in logistics systems in companies and in the supply chain. The proper function of warehouse operations depends on, among other things, the type of the used technology and their utilization. The research in this article is focused on the design of a warehouse system. The selection of a suitable warehouse system is a current research topic as the warehouse system has an impact on warehouse capacity and utilization and on the speed of storage activities. The paper presents warehouse system design methodology that was designed applying the logistics principle-systematic (system) approach. The starting point for designing a warehouse system represents of the process of design logistics systems. The design process consists of several phases: project identification, design process paradigm selection, system analysis, synthesis, and project evaluation. This article’s contribution is the proposed methodology and design of the warehouse system for the specified conditions. The methodology was implemented for the design of a warehouse system in a cold box, which is a part of a distribution warehouse. The technology of pallet racking was chosen in the warehouse to store pallets. Pallets will be stored and removed by forklifts. For the specified conditions, the warehouse system was designed for two alternatives of racking assemblies, which are served by forklifts. Alternative 1—Standard pallet rack with wide aisles and Alternative 2—Pallet dynamic flow rack. The proposed systems were compared on the basis of selected indicators: Capacity—the number of pallet places in the system, Percentage ratio of storage area from the box area, Percentage ratio of handling aisles from the box area, Access to individual pallets by forklift, Investment costs for 1 pallet space in EUR. Based on the multicriteria evaluation, the Alternative 2 was chosen as the acceptable design of the warehouse system with storage capacity 720 pallet units. The system needs only two handling aisles. Loading and unloading processes are separate from each other, which means that there are no collisions with forklifts. The pallets with the goods are operated on the principle of FIFO (first in, first out), which will facilitate the control of the shelf life of batches or series of products. The methodology is a suitable tool for decision-making in selecting and designing a warehouse system.
Our paper is focused on data evaluation about the full recycling of waste by special statistical software and by using the principles of logistics. The paper goes further than the paper entitled "Environmental assessment of waste recycling based on principles of logistics and computer simulation design," which outputs a number of data that need to be reviewed and evaluated separately. Data, representing 15 types of waste for 5 years, enter the analysis. There were the types of waste that make up the most important part of the total waste production by means of descriptive statistics. Thanks to this, they were identified as the most important (from the production point of view) plastic granules with an average of 755.05 t/month, glass with an average of 672.233 t/month and paper with the average of 645.25 t/month. The persistence of particular waste type generation was examined by the variation coefficient in order to reduce the risk of supply of these secondary raw materials in the downstream supply chain. Selected waste elements can be considered relatively stable with a variation coefficient in the range 2.4-4.1%; the least stable type is electronic dust with a coefficient of variation of up to almost 23%.
This article evaluates changes in the organization of transport on urban roads through the transport model in the OmniTRANS program. The selected location for the case study in this article is the internal traffic circuit of Kosice, which borders the historic core of the city. Currently, the proposal is being prepared to change the organization of transport in the town’s monument reserve and its protection zone. The transition to a one-way road around the historic center is being considered. Before introducing the new proposed change in traffic, it is necessary to test this proposed change and determine how it will affect the traffic situation. The aim of this article is to compare the current transport organization with the proposed change in transport organization in terms of traffic intensity. The use of transport models in the world is not a new concept, but it is often not used in the conditions of the Slovak Republic. However, traffic and simulation models can save money and time and avoid possible unexpected problems before putting the proposed changes into practice. Solving the given problem is an excellent benefit for transport planning and traffic engineering for Kosice and other places with a similar arrangement of the historical center and a similar number of inhabitants. The proposed changes can be tested by modelling traffic and then to adjust them when the cons are identified. Thanks to the traffic simulation model, it is possible to compare the capacity load of the inner traffic circuit of the city before and after the introduction of the one-way circuit.
Uranium is one of the strategic minerals used mainly in energetics. The main purpose of uranium mining is to achieve maximum production to meet the rapidly growing demand for energies. It needs to become aware that technological progress in mining processes could significantly reduce the negative impacts associated with environmental, economic, and social risks. Uranium mining is one of the most controversial topics. It is dealt with by many experts and scientists around the world. Various methods and technologies of uranium mining are encountered in professional journals, as well as political or socio-economic decisions based on the impact and importance of the energy potential of uranium deposits, or the environmental impacts of uranium mining. The deposit of Kuriskova is one of the most perspective deposits not only in Slovakia but also in the world. The deposit is located near the town of Kosice (with near 240,000 inhabitants) and near the recreational area of Jahodna in the east of the Slovak Republic. The analysis and determination of the energy potential of the deposit of Kuriskova shows that uranium reserves from this deposit would be able to fully cover the needs for nuclear power plants for the production of nuclear fuel, in the Slovak Republic, even in the longer term. With the above-mentioned energy potential of the deposit of Kuriskova at the level of 600 TWh, nuclear power plants in the Slovak Republic are able to be supplied with raw materials from the deposit of Kuriskova for about 40 years with the current amount of electricity produced (approx. 15 TWh). Therefore, for the purposes of this research, a proposal for the extraction of uranium reserves at the deposit of Kuriskova was made. Based on it, it is possible to determine the amount of recoverable uranium reserves from the deposit. A methodology has been determined with mining this proposal, which takes into account the basic criteria of uranium deposit mining, which was used for the selection of a suitable mining technology for the uranium deposit of Kuriskova.
This article describes the design of a simple forecasting system and its practical application to predict the sporadic needs for a spare part. The article shows new approach already implemented in the special servicing and production company in Slovakia and its results during a short period of performance after its implementation. Such a proposed model can be a part of the purchase planning of spare parts within the company’s logistics system. In some companies, the material flow of spare parts is dominant element in terms of logistics costs. Their management is therefore important for cost optimization, customer satisfaction and market sustainability in a competitive environment. The article, in its introductory part, provides an overview of similar practical solutions within the research of this topic, but many models are designed to be applied in a global market environment and predict the amount of spare parts needed in different industries. However, these models are difficult to use for the needs of a small enterprise, because the main problem lies in the time of a spare part demand rather than its quantity. If there is a need for a specific spare part, which costs several hundred or thousands of euros, but the consumption is only a few pieces per year or more than a year, the time prediction of required spare parts is therefore crucial.
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