For the optimal design and selection of solar energy conversion systems, as well as for other fields of interest, such as architecture, agriculture, hydrology and ecology, the knowledge of accurate ...global solar radiation data is extremely important. However, due to the cost and difficulty in solar radiation measurements these data are not easily available for many countries. Therefore many empirical models have been developed by various researchers to predict global solar radiation from readily available data. The number of developed models is relatively high, which makes it difficult to choose the most appropriate one for a particular purpose and site. There are several studies in which authors evaluate different models for specific location. However, there is no comprehensive study in which these models are evaluated in case of global use. The main objective of this study is to evaluate different solar radiation models on global scale, which might be helpful in the selection of the most appropriate and accurate model based on the available sunshine data. Using the radiation data corresponding to 924 sites throughout the world we conducted a detailed statistical analysis of 101 different solar radiation models that are available in literature. Ten statistical indicators were used to assess models performance. In addition, we introduced specific global performance indicator (GPI), by means of which all analyzed models are depicted with a single parameter and easily ranked.
In many solar applications knowing diffuse solar radiation on horizontal surface represents an important requirement. The measurement of diffuse radiation is quite expensive, and because of that ...solar radiation measurements are not easily available in many locations around the world. Therefore many empirical correlations have been developed by various researchers to predict diffuse radiation from available meteorological data. The main objective of this study is to assess and compare different diffuse solar models available in the literature. These empirical models have been derived for specific location using long term measurements for that location. There is no general formula to calculate the diffuse solar radiation at any location in the world. While there are several studies in which authors compare different diffuse models for specific location, there is no comprehensive study in which these models are compared on a global scale. In this study we used statistical analysis to evaluate performance of analyzed models using long term measurements at 267 different sites around the world. Ten statistical quantitative indicators are used to evaluate different diffuse solar radiation models. The results are also visually presented by means of Taylor diagrams, which give a clear picture of how close a particular model is to measured data and how it is relatively compared to other models.
This paper examines whether a long-run relationship exists between CO
2
emissions and selected variables: real gross domestic product per capita, inward stock of foreign direct investments, gross ...fixed capital formation, industry, value added and energy use per capita for Colombia, Indonesia, Viet Nam, Egypt, Turkey and South Africa countries in the period of 1989-2016. We used panel unit root testing, followed by panel cointegration tests and panel causality. The results clearly prove the existence of a bidirectional long-run causal relationship between all the variables except between CO
2
emissions and GDP and CO
2
emissions and GFCF. Major finding of the short-run causality analysis is that CO
2
emission in the short run does not result in changes of other variables. On the other hand, all variables except foreign direct investments (FDI) cause the changes in the CO
2
emissions, and there is a positive bidirectional causal relationship between GDP and FDI, between GFCF and FDI, and between GFCF and IVA. Finally, positive unidirectional causal relationship also exists, running from GDP to IVA, GDP to ENUSE, IVA to FDI and ENUSE to FDI.
Traffic is the main source of noise in urban environments and significantly affects human mental and physical health and labor productivity. Therefore it is very important to model the noise produced ...by various vehicles. Techniques for traffic noise prediction are mainly based on regression analysis, which generally is not good enough to describe the trends of noise. In this paper the application of artificial neural networks (ANNs) for the prediction of traffic noise is presented. As input variables of the neural network, the proposed structure of the traffic flow and the average speed of the traffic flow are chosen. The output variable of the network is the equivalent noise level in the given time period Leq . Based on these parameters, the network is modeled, trained and tested through a comparative analysis of the calculated values and measured levels of traffic noise using the originally developed user friendly software package. It is shown that the artificial neural networks can be a useful tool for the prediction of noise with sufficient accuracy. In addition, the measured values were also used to calculate equivalent noise level by means of classical methods, and comparative analysis is given. The results clearly show that ANN approach is superior in traffic noise level prediction to any other statistical method.
The paper examines the intensity of the infrastructure impact (roads, port infrastructure, air transport, electricity supply) on improving competitiveness quantified by Gross Domestic Product per ...capita (GDP pc) of twelve Emerging and Developing European countries according to the Global Competitiveness Index (GCI ) of the World Economic Forum (WEF) and the methodology for the period 2007 - 2017. The impact of infrastructure as one of the basic factors of competitiveness on GDP growth per capita was seen through single (linear and exponential) and panel data linear regression analyses. The results of the research showed that the development of the infrastructure has a very positive impact on GDP growth per capita. Positive interdependence is far more evident in six economically less developed Emerging and developing European countries that were (Croatia) or are the current members of CEFTA (Albania, Bosnia and Herzegovina, Macedonia, Montenegro and Serbia) in comparison to the six remaining Emerging and developing European countries (Bulgaria, Hungary, Lithuania, Poland, Romania and Turkey) in the observed period. Taking into consideration the fact that all CEFTA countries analyzed are at some stage of their accession to the European Union, the conclusion is that they must pay special attention to the development of infrastructure.
In this paper, we investigate the influence of R&D expenditure on economic growth in the EU28 during the period of 2002-2012. For this purpose, we constructed a multiple regression model, which ...showed that, ceteris paribus, an increase in R&D expenditure as a percentage of GDP by 1% would cause an increase of real GDP growth rate by 2.2%. This model takes into consideration actual financial crises and emphasises the negative influence of fertility rate in the EU28 on economic growth. We believe that the achieved research results can be beneficial to the economic policy makers in the innovation and demographic areas.
The paper presents an empirical analysis of the impact of institutional reform policies and institutional quality on the economic growth of five Western Balkan countries (WB countries: Serbia, ...Montenegro, Bosnia and Herzegovina, Northern Macedonia and Albania) in the period 2006-2016. It was developed its own model of quantification concerning the impact of the most important indicators of the quality of institutions on the economic growth of these countries, which are in a delayed phase of transition and at some stage in the EU accession process. Achieving high and stable rates of economic growth for WB countries becomes the ultimate prerequisite for completing the EU transition and accession process. In order to improve growth dynamics, among other things, it is necessary to identify key drivers of growth and to model appropriate growth and development policies based on the results obtained. In the paper, WB countries were viewed as a whole. By empirically testing the impact of individual quality indicators of institutions on economic growth, according to the World Bank Governance Indicators methodology by using panel data multiple linear regression analysis, the largest statistically significant and positive impact came from the Government Effectiveness and Regulatory Quality variable. The intensity of the impact of the Control of Corruption and Rule of Law variable on GDP per capita is slightly weaker, but it is also very pronounced. In this respect, the empirical results obtained can be a useful framework for modeling the development policies of WB countries. They represent an important guide for policy makers to implement measures aimed at improving the quality of institutions and at the same time modeling economic growth policies.
The paper examines the trade competitiveness of the wood industry as a whole and some of its parts (Cork and wood, Cork and wood manufactures and Furniture and parts) of fi ve countries of South ...Eastern Europe (Serbia, Croatia, Bulgaria, Romania and Bosnia & Herzegovina) by using six indicators (Revealed Comparative Advantage – RCA, Index of Trade Performance – RCA2, Competitiveness Growth Index – RCA1, Michaely Index – MI, Index of Contribution to the Trade Balance – CTB and Grubel-Lloyd Index – GLI) in the period 2000-2015. On the basis of the results obtained, it was concluded that the wood industry of these countries observed as a whole has great export potential and that it significantly participates in their processing industry. The results of the survey show that companies from the wood industry viewed as a whole are competitive on the domestic market. However, this cannot be said of the international competitiveness of the timber industry of these countries. To be specific, the production of cork and wood from Bulgaria and Serbia, cork and wood manufactures excluding furniture from Bulgaria, Serbia and Croatia, as well as furniture and parts manufacturers from Bulgaria do not have a competitive advantage in the international market. By combining the values of six competitiveness indicators, it can be concluded that there is a statistically significant difference in the competitiveness of the wood industry of the countries observed. It can also be concluded that the degree of wood processing has a positive impact on their export competitiveness, this impact not being statistically significant, and that the level of finalization of production did not have a positive impact on the competitiveness of the wood industry of the selected countries of Southeastern Europe.
U radu se istražuje trgovinska konkurentnost drvne industrije pet zemalja jugoistočne Europe (Srbije, Hrvatske, Bugarske, Rumunjske te Bosne i Hercegovine), i to u cjelini i po dijelovima (pluto i drvo, proizvodi od pluta i drva, namještaj i dijelovi za namještaj). Istraživanje je provedeno u razdoblju od 2000. do 2015. uz pomoć šest pokazatelja konkurentnosti (utvrđene komparativne prednosti – RCA, indeksa neto poslovanja – RCA2, indeksa rasta konkurentnosti – RCA1, Michaely indeksa – MI, indeksa doprinosa trgovinskoj bilanci – CTB i Grubel-Lloyd indeksa – GLI). Iz dobivenih je rezultata zaključeno da drvna industrija navedenih zemalja, promatrana u cjelini, ima velik izvozni potencijal i da značajno sudjeluje u njihovoj prerađivačkoj industriji. Rezultati istraživanja pokazuju da su poduzeća iz sektora drvne industrije, promatrana u cjelini, konkurentna na domaćem tržištu. Međutim, to se ne može reći i za međunarodnu konkurentnost drvne industrije tih zemalja. Konkretno, proizvodnja pluta i drva iz Bugarske i Srbije, proizvodi od pluta i drva iz Bugarske, Srbije i Hrvatske, kao i namještaj i dijelovi za namještaj iz Bugarske nemaju konkurentsku prednost na međunarodnom tržištu. Kombiniranjem vrijednosti šest pokazatelja konkurentnosti utvrđena je statistički značajna razlika u konkurentnosti drvne industrije promatranih zemalja. Također se može zaključiti da stupanj obrade drva ima pozitivan utjecaj na njihovu izvoznu konkurentnost, ali taj utjecaj ipak nije statistički značajan. Nadalje, uočeno je da stupanj finalizacije proizvodnje nije pozitivno utjecao na konkurentnost drvne industrije promatranih zemalja jugoistočne Europe.
For a few last decades, economists have been showing a continuous interest in doing research in the key factors of regional growth and the developmental convergence (divergence) of the region. ...However, beside the wealth of theoretical and empirical research in the mentioned categories, it is obvious that there is still no generally accepted explication of the key factors of regional growth. The same conclusion can be borne in mind in relation to the existence of the connection between the accepted economic growth of a country and a tendency to increase, i.e. decrease regional inequalities. The paper presents a theoretical explication of a) the key factors of regional growth and b) the phenomenon of developing the convergence (divergence) of the region, five representative theoretical approaches to the regional economy (classical, neoclassical, endogenic, new economic geography and spatial innovation systems). The current economic reality on the global plan which speaks of an increasing regional inequality confirms the accuracy of the theoretical considerations of the representatives of the contemporary theoretical approaches related to the analyzed issues.
In this paper, on the basis of relevant statistical tests, the influence of the electoral process on the trajectory of fiscal indicators in the transition countries is analyzed. The aim of the ...research is to identify the political manipulation of certain fiscal policy mechanisms in transition countries.The focus of the survey is on the growth of general government spending, the reduction of general government revenues and the creation of budget deficits as the coherent consequences of fiscal expansion in the pre-election period. By testing, there is no relevant evidence of the use of tax incentives as a form of political action on the economic sphere. On the other hand, the results of the survey indicate that in the observed countries, there really is a rise in government spending in the period before the election process and, consequently, the growth of budget deficits. However, according to the same findings, in the post-election period there is no reduction in consumption. Growth in general governments consumption continues, but to a lesser degree, which in turn leads to the correction of the budgetary balance.
PDF
