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EN
The paper presents a method for evaluating the effectiveness and risks of investment projects and the selection of efficient portfolios in a situation where parameters in the calculation of effectiveness are expressed in the form of interactive fuzzy numbers. Fuzzy model simulations are used to perform arithmetic operations on interactive fuzzy numbers. The process of selecting investment projects takes into account statistical and economic dependences between projects.
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EN
The problem of optimal assignment of respondents to internet surveys has been considered. The task is taken from a leading online research company in Central and Eastern Europe, which runs several dozen surveys in parallel. Each survey is assigned a target number of responses to be collected and unique selection criteria for choosing respondents based on their socio-demographic data. A mathematical programming model has been proposed that enables us to find an optimal mechanism for assigning respondents to surveys so as to minimize the required total number of invitations to surveys issued. A side effect of the assignment procedure is that the samples obtained are not representative of the population under survey. Therefore, a sample weighting scheme has been developed that takes this fact into account and allows us to obtain unbiased estimators of the characteristics of the population surveyed.
PL
W artykule przedstawiono nową metodę wyboru efektywnych portfeli przedsięwzięć inwestycyjnych. Problem wyboru portfeli sformułowano w postaci zadania optymalizacji wielokryterialnej. Opracowany algorytm umożliwia poszukiwanie niezdominowanych portfeli przedsięwzięć inwestycyjnych. Kryteriami wyboru są: maksymalizacja wartości oczekiwanej NPV i minimalizacja semiodchylenia standardowego NPV portfela. Metoda umożliwia wybór portfeli przy uwzględnieniu zależności statystycznych i ekonomicznych pomiędzy przedsięwzięciami inwestycyjnymi. Jest ona dostosowana do przedsiębiorstw o wieloetapowym cyklu produkcji, na przykład przedsiębiorstwa przemysłu metalurgicznego czy chemicznego.
EN
A new algorithm for selecting an effective investment project portfolio from a collection of projects developed by a company has been presented in this paper. The problem of selecting an investment project was formulated as multi-objective optimization problem. The algorithm is suited for enterprises with multistage production cycles, e.g. enterprises in the metallurgical or chemical industry. During the selection process the method takes into account statistical and economic interdependencies existing among projects. Upon choosing projects the algorithm takes into account twp criteria: maximization of the expected NPV and minimization of project portfolio risk. A company may develop an effective investment project portfolio for a few years ahead. The algorithm makes it possible to search for Pareto optimal solutions. It links computer simulation methods with a genetic algorithm and standard procedure for linear optimization. An example of the use of the algorithm for selecting projects in the metallurgical industry is presented.
EN
Background: Agriculture is a production system in which the economic principles of organisation act in mutual dependence with its ecological boundaries. Objectives: Building on this premise, the paper evaluates performance of a chosen agricultural production system (dairy production in Slovenia) from two complementary perspectives, the socio-economic and the biophysical. Methods/Approach: The latter is presented by means of emergy analysis, which is a system-based approach that measures the aggregate work of biosphere needed for the provision of goods or services in the units of solar energy joules. The novelty aspect of this paper is the introduction of emergy indicators into the standard socioeconomic optimisation model of the chosen agricultural production system. The optimisation model based on linear mathematical programming is designed to empirically investigate different alternatives to the sector’s reorganisation. Results: The results of the optimisation models suggest considerable restructuring of the sector and, consequently, large discrepancies in the sector’s performance. Conclusions: The results suggest that further expansion of organic production systems as a result of a stronger environmental focus in farm management would improve the sector from both, the socio-economic and the emergy perspective. Moreover, even pursuing certain socio-economic targets may improve the sector’s biophysical performance and lower pressure on the local environment.
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