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In multi-criteria decision-making (MCDM) problems the decision-maker is often forced to accept a not ideal solution. If the ideal choice exists, it would be certainly chosen. The acceptance of a non- ideal solution leads to some inadequate properties in the chosen solution. MCDM methods help the decision-maker to structure his needs considering different units, in which the properties of the solutions are expressed. Secondly, with MCDM tools the assessment of the available solutions can be calculated with consideration of the decision-maker’s needs. The incorporation of the cost criterion into the decision maker’s preferences calculation, and the solution assessment calculation, deprives the decision-maker of the ability to calculate the financial result of the decision he must make. A new multi-criteria decision making with cost criterion analysed at the final stage (MCDM-CCAF) method is developed based on principle of Pareto optimal decisions. It is proposed to exclude the cost criterion from the MCDM analysis and consider it at the final phase of the decision-making process. It is illustrated by example solutions with consideration of cost criterion and without it. It is proposed to apply the invented post-processing method to all MCDM analyses where the cost criterion of analysed variants is considered.

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Polish economy experienced significant changes during the past 30 years. System transformation that began in the 1980's and was enhanced by Poland's entry to the European Union in 2004 significantly influenced economic development. Apart from tough history experiences, they formed the shape of national economy which can be observed nowadays. It was a long and difficult process. During political and economic rapid changes greater numbers of price collusions and other illegal practices can be observed than during the stable development of national economy. Authors selected and reviewed the most important anti-competitive cases in the construction industry from the past 30 years in Poland. The review includes not only cases that were officially justified and penalized-like the collusion of portland cement big producers-but also cases of collusion suspicion on highway and express roads that ended with acquittal court verdicts.

Over the recent years, there is a growing interest in concrete prefabrication. Many of the currently operating concrete plants have implemented systems that increase the quality of manufactured products, have expanded highly automated production lines and have clearly reduced wastes and energy consumption. However, one of the problems often encountered in the construction industry is the inefficient organization of logistics processes. Proper shipments planning of aggregates consisting of the selection of their appropriate quantity and the aggregate stock, corresponding to the needs of concrete plants should contribute to lowering costs. Therefore, it is necessary to carry out the optimization, the aim of which is to minimize costs, as well as to maximize the fulfillment of the degree of expected needs of concrete plants. This paper presents a model that allows purchase strategy optimization of aggregates with different grain size fraction. For research purposes, three separate aggregate stocks and five different concrete plants are considered.