Loghman Hatami-Shirkouhi; Amir Nazari-Shirkouhi; Homa Samadi; Mehran Nemati
Volume 12, Issue 46 , October 2012, , Pages 65-84
Abstract
Stock exchange is an organized and major institution in the stock market. Evaluating the performance of companies in stock exchange and selecting type of trade entity are important subjects for finance mangers and investors; because by a comprehensive assessment, investment risk could be decreased to ...
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Stock exchange is an organized and major institution in the stock market. Evaluating the performance of companies in stock exchange and selecting type of trade entity are important subjects for finance mangers and investors; because by a comprehensive assessment, investment risk could be decreased to an acceptable level. This paper aims to evaluate and rank joint stock companies by data envelopment analysis in the uncertain environment. 50 companies listed by stock exchange organization under title “50 more active companies of Tehran stock exchange-first quarter of 2010” are studied by 10 effective measures on performance evaluation. Results show that fuzzy data envelopment analysis method is an appropriate approach for modeling of fluctuations and uncertainties in different fiscal years’ data and assessment of performance of companies in uncertain states of measures.
Ali Ghanbari; Seyed Hadi Makhzan Moosavi
Volume 11, Issue 42 , October 2011, , Pages 91-113
Abstract
The size of the underground economy (UE) is valuable information in the
formulation of macroeconomic and fiscal policy. According to the hidden nature of
underground economy, there will be a problem for studying and measuring it, therefore
methods of common measure have set about estimating these ...
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The size of the underground economy (UE) is valuable information in the
formulation of macroeconomic and fiscal policy. According to the hidden nature of
underground economy, there will be a problem for studying and measuring it, therefore
methods of common measure have set about estimating these activities so that it will face
with exclusive assumptions. This study applies fuzzy set theory and fuzzy logic to construct
an annual time-series for the (unobservable) Iran UE over the period 19782006. Three
major factors affecting the size of the UE, the effective tax rate, unemployment rate and the
degree of government regulations, are used. The result of this study has been compared with
MMIC model. Although these two studies have different procedures, they have generally
defensive and almost similar results in underground economy. In the meanwhile the featured
phenomenon of fuzzy values show that it can present better patterns in underground
economy. The advantage of applying fuzzy logic is twofolds. First, it can avoid the complex
calculations in conventional econometric models. Second, fuzzy rules with linguistic terms
are easy for human to understand it.
