On topological indices of fullerenes Baca, Martin; Horvathova, Jarmila; Mokrisova, Martina ...
Applied mathematics and computation,
01/2015, Volume:
251
Journal Article
Peer reviewed
Two degree based topological indices, the atom-bond connectivity (ABC) and the geometric–arithmetic (GA) indices of fullerene networks and carbon nanotube networks are studied. Expressions for ABC ...and GA indices for these important classes of networks are obtained.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Predicting the risk of corporate bankruptcy is one of the most important challenges for researchers dealing with the issue of financial health evaluation. The risk of corporate bankruptcy is most ...often assessed with the use of early warning models. The results of these models are significantly influenced by the financial features entering them. The aim of this paper was to select the most suitable financial features for bankruptcy prediction. The research sample consisted of enterprises conducting a business within the Slovak construction industry. The features were selected using the domain knowledge (DK) approach and Least Absolute Shrinkage and Selection Operator (LASSO). The performance of VRS DEA (Variable Returns to Scale Data Envelopment Analysis) models was assessed with the use of accuracy, ROC (Receiver Operating Characteristics) curve, AUC (Area Under the Curve) and Somers’ D. The results show that the DK+DEA model achieved slightly better AUC and Somers’ D compared to the LASSO+DEA model. On the other hand, the LASSO+DEA model shows a smaller deviation in the number of identified businesses on the financial distress frontier. The added value of this research is the finding that the application of DK features achieves significant results in predicting businesses’ bankruptcy. The added value for practice is the selection of predictors of bankruptcy for the analyzed sample of enterprises.
Diagnosing the financial health of companies and their performance is currently one of the basic questions that attracts the attention of researchers and experts in the field of finance and ...management. In this study, we focused on the proposal of models for measuring the financial health and performance of businesses. These models were built for companies doing business within the Slovak construction industry. Construction companies are identified by their higher liquidity and different capital structure compared to other industries. Therefore, simple classifiers are not able to effectively predict their financial health. In this paper, we investigated whether boosting ensembles are a suitable alternative for performance analysis. The result of the research is the finding that deep learning is a suitable approach aimed at measuring the financial health and performance of the analyzed sample of companies. The developed models achieved perfect classification accuracy when using the AdaBoost and Gradient-boosting algorithms. The application of a decision tree as a base learner also proved to be very appropriate. The result is a decision tree with adequate depth and very good interpretability.
In this paper, the following research problem was addressed: Is DEA (Data Envelopment Analysis) method a suitable alternative to Altman model in predicting the risk of bankruptcy? Based on the ...above-mentioned research problem, we formulated the aim of the paper: To apply DEA method for predicting the risk of bankruptcy and to compare its results with the results of Altman model. The research problem and the aim of the paper follow the research of authors aimed at the application of methods which are appropriate for measuring business financial health, performance and competitiveness as well as for predicting the risk of bankruptcy. To address the problem, the following methods were applied: financial ratios, Altman model for private non-manufacturing firms and DEA method. When applying DEA method, we formulated input-oriented DEA CCR model. We found that DEA method is an appropriate alternative to Altman model in predicting the risk of possible business bankruptcy. The important conclusion is that DEA allows us to apply not only outputs but also inputs. Since prediction models do not include these indicators, DEA method appears to be the right choice. We recommend, especially for Slovak companies, to apply cost ratio when calculating risk of bankruptcy.
This paper focuses on the financial health prediction of businesses. The issue of predicting the financial health of companies is very important in terms of their sustainability. The aim of this ...paper is to determine the financial health of the analyzed sample of companies and to distinguish financially healthy companies from companies which are not financially healthy. The analyzed sample, in the field of heat supply in Slovakia, consisted of 444 companies. To fulfil the aim, appropriate financial indicators were used. These indicators were selected using related empirical studies, a univariate logit model and a correlation matrix. In the paper, two main models were applied—multivariate discriminant analysis (MDA) and feed-forward neural network (NN). The classification accuracy of the constructed models was compared using the confusion matrix, error type 1 and error type 2. The performance of the models was compared applying Brier score and Somers’ D. The main conclusion of the paper is that the NN is a suitable alternative in assessing financial health. We confirmed that high indebtedness is a predictor of financial distress. The benefit and originality of the paper is the construction of an early warning model for the Slovak heating industry. From our point of view, the heating industry works in the similar way in other countries, especially in transition economies; therefore, the model is applicable in these countries as well.
This paper focuses on business financial health evaluation with the use of selected mathematical and statistical methods. The issue of financial health assessment and prediction of business failure ...is a widely discussed topic across various industries in Slovakia and abroad. The aim of this paper was to formulate a data envelopment analysis (DEA) model and to verify the estimation accuracy of this model in comparison with the logit model. The research was carried out on a sample of companies operating in the field of heat supply in Slovakia. For this sample of businesses, we selected appropriate financial indicators as determinants of bankruptcy. The indicators were selected using related empirical studies, a univariate logit model, and a correlation matrix. In this paper, we applied two main models: the BCC DEA model, processed in DEAFrontier software; and the logit model, processed in Statistica software. We compared the estimation accuracy of the constructed models using error type I and error type II. The main conclusion of the paper is that the DEA method is a suitable alternative in assessing the financial health of businesses from the analyzed sample. In contrast to the logit model, the results of this method are independent of any assumptions.
In modern agriculture, mineral fertilizers are considered to be a significant enhancing factor. They promote soil fertility, particularly in sandy soils. Farmers should be aware of the effects of ...fertilizers on the soil environment. Here, we report the results of three long-term experiments with durations of 25, 41 and 94 years conducted in a sandy soil at the experimental station of the Warsaw University of Life Sciences – SGGW in Skierniewice, Poland. The soil physical properties and nutrient regime were monitored under a set of experimental treatments: Control – no fertilizer, NPK – NPK fertilizers, CaNPK – CaNPK fertilizers in the 41-year and 94-year-long experiments, and FYM – farmyard manure as control, FYM+NPK – farmyard manure+NPK fertilizers and FYM+CaNPK – farmyard manure+CaNPK fertilizers in the 25-year-long experiment. Only the 41-year-long experiment showed a significant decrease in bulk density by 7% under NPK treatment compared to control. Total and available P increased significantly across experiments and fertilization treatments compared with the corresponding controls, most remarkably in the 41-year-long experiment. In the 94-year-long experiment, total Ca and Mg rose by 168% and 45% under CaNPK treatment, respectively, relative to the control. Total organic carbon increased considerably across experiments. Similarly, total N and S increased in NPK treatment significantly by 67% and 56%, respectively compared with the control in the 41-year-long experiment. Overall, the highest number of correlations between soil physical properties and nutrient content was determined in the 94-year-long experiment. The obtained results show positive effects of FYM on the content of soil nutrients.
•Bulk density and porosity were not higher than the threshold limits in all long-term experiments (LTEs).•Higher total P and Ca resulted in their higher available forms in LTEs.•In all LTEs, the mineral fertilization increased TOC.•The positive effect of FYM on the content of soil nutrients was observed.•The favourable nutrient ratios can be responsible for the improvement of soil properties in sandy soils.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Various methods are used when building bankruptcy prediction models. New sophisticated methods that are already used in other scientific fields can also be applied in this area. Graph theory provides ...a powerful framework for analyzing and visualizing complex systems, making it a valuable tool for assessing the sustainability and financial health of businesses. The motivation for the research was the interest in the application of this method rarely applied in predicting the bankruptcy of companies. The paper aims to propose an improved dynamic bankruptcy prediction model based on graph theoretical modelling. The dynamic model considering the causality relation between financial features was built for the period 2015–2021. Financial features entering the model were selected with the use of Domain knowledge approach. When building the model, the weights of partial permanents were proposed to determine their impact on the final permanent and the algorithm for the optimalisation of these weights was established to obtain the best performing model. The outcome of the paper is the improved dynamic graph theoretical model with a good classification accuracy. The developed model is applicable in the field of bankruptcy prediction and is an equivalent sophisticated alternative to already established models.
In 2017 the field experiments were established at two localities of the South-west Slovakia (1 Dolná Streda: sandy Arenosol and 2 Veľké Úľany: loamy Chernozem). The experiments involved biochar ...substrates (1 BS1 mix biochar, sheep manure and 2 BS2 mix biochar, sheep manure and digestate) in two application doses (10 and 20 t ha-1), which were applied independently compared with the unfertilized control (Co-NF) and combined with additional fertilization versus the fertilized control (Co-F), in order to verify their impacts on the changes of soil properties. In the spring and autumn of 2018 – 2020, within these experiments the soil samples were taken to determine the range of effect of the tested biochar substrates (BS) and also their combination with fertilization (F) on the changes of soil pH and surface charge of soil particles in the soils different in texture. The results pointed out the fact that a more significant effect of tested BS on soil pH was detected in sandy soil than loamy soil. In sandy soil, only the application of BS2 in doses 10 and 20 t ha-1 statistically significantly increased the soil pH in H2O in comparison with Co-NF. The application BS1 + F in dose 10 t ha-1 and BS2+F in dose 20 t ha-1 statistically significantly increased pH in KCl compared with Co-F. The fertilization to BS eliminated the considerable decrease of the soil pH in H2O both soils. In sandy soil, pH was substantially regulated by the content of alkali cations themselves in BS; however, in loamy soil, it occurred as a result of the increase of the content of soil organic carbon after the application of BS (R2 = 0.339), but also BS + F (R2 = 0.468). In sandy soil, the application of BS itself, owing to the change of the surface charge, influenced predominantly the sorption of anions. Conversely, the additional fertilization to BS treatments had an impact on the sorption of cations. In loamy soil, the application of BS and BS + F as a result of the change of surface charge did not have any significant effect on the total soil sorption.
The paper deals with the issue of analyzing the financial failure of businesses. The aim was to select key performance indicators entering the DEA model. The research was carried out on a sample of ...343 Slovak heat management companies. When addressing the research problem, we made use of multidimensional scaling (MDS) and principal component analysis (PCA), which pointed out the areas of financial health of companies that may predict their financial failure. The core of our interest and research was the data envelopment analysis (DEA) method, which represents a more exact approach to the assessment of financial health. The important finding is that the statistical graphical methods - PCA and MDS - are very helpful in identifying outliers and selecting key performance indicators entering the DEA model. The benefit of the paper is the identification of companies that are at risk of bankruptcy using the DEA method. The originality is the selection of key inputs and outputs to the DEA model by the PCA method.
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