6 resultados para Models, Theoretical
em Corvinus Research Archive - The institutional repository for the Corvinus University of Budapest
Resumo:
A tanulmny a PPP klnbz strukturlis modelljeinek csoportostst mutatja be, az egyes tpusok rvid rendszerez ttekintsvel. A tipolgik vizsglata hasznos ahhoz, hogy a PPP projektek struktrjnak kialaktsakor a klnbz lehetsgeket mrlegelni tudjuk. Tbbfle megkzeltsben lehet a modelleket tipizlni. Az egyttmkds clja alapjn a hatkonysg-, a minsg- s a finanszrozs-orientlt modellek a legelterjedtebbek, a kockzatmegoszts mdja alapjn BOT, DBFO s koncesszis vltozatok, a haszonmegoszts szablyozsa alapjn rplafon-szablyozs, kzvetlen haszonszablyozs, fixdjas s rnykras megoldsok a leginkbb bevettek. A tanulmny ezek elemz bemutatsa alapjn arra a kvetkeztetsre jut, hogy a gyakorlati megoldsok a legtbb esetben az elmleti tpusok valamilyen kombincijt tartalmazzk, a konkrt eset feltteleinek megfelelen. gy a gyakorlatban a fix tipolgik helyett alkalmasabb gy megkzeltennk a PPP-t, mint egy folyamatosan vltoz, a helyi ignyekhez idomul jelensget. A haszonszablyoz tipolgia kapcsn a tanulmny mellklete rvid ttekintst nyjt a PPP esetben kritikus mltnyos haszon becslsnek lehetsges megoldsairl is. = This study shows a categorization of the different structural models of Public-Private Partnership (PPP) projects. The typologies are useful to assess the available options when decisions on PPP project structures are made. There are different categorizing aspects. Based ont he key purpose of the partnership there are efficiency, quality and financing focused models. From a risk sharing point of view, BOT, DBFO and concession models are most typical. Regarding the regulation of returns price-cap models, open book models, fixed price and shadow pricing models are most common. Based on the analytical assessment of these, they study concludes that actual projects are mostly a combination of theoretical types, as required by the given case. Therefore in practice, it is more appropriate to approach PPP projects as a constantly shaping concept, adjustable to particular conditions. Supporting the approaches to the regulation of returns, an appendix of the study summarizes the different methods to estimate fair returns, a critical issue in PPP projects.
Resumo:
A svosan rgztett devizarfolyamok elmleti s gyakorlati vizsglatai a nemzetkzi kzgazdasgtan egyik legnpszerbb tmakre volt a kilencvenes vek elejn. A gyakorlati mdszerek kzl az alkalmazsok s hivatkozsok szma tekintetben az gynevezett eltoldssal igazts mdszere emelkedett ki. A mdszert alkalmaz szerzk szerint amg a lebeg rfolyam devizk elrejelzse cltalan feladatnak tnik, addig svos rfolyam esetn az rfolyam svon belli helyzetnek elrejelzse sikeresen vgezhet. E tanulmny bemutatja, hogy az Eurpai Monetris Rendszer s az szakeurpai llamok svos rfolyamrendszereinl e mdszer alkalmazsval addott eredmnyek pldul a lebeg rfolyam amerikai dollrra s az egysggykfolyamatok tbbsgre is rvnyesek. A tanulmny feltrja e ltszlagos ellentmonds okait, s bemutat egy olyan, a svos rfolyamrendszerek fbb megfigyelt jellemzire pl modellt, amelynek keretei kztt a svon belli rfolyam elrejelzse nem felttlenl lehetsges, mert a lertkels eltti idszakban a svon belli rfolyam alakulsa kaotikus lehet. / === / Following the development of the first exchange rate target zone model at the end of the eighties dozens of papers analyzed theoretical and empirical topics of currency bands. This paper reviews different empirical methods to analyze the credibility of the band and lays special emphasis on the most widely used method, the so-called drift-adjustment method. Papers applying that method claim that while forecasting a freely floating currency is hopeless, predicting an exchange rate within the future band is successful. This paper shows that the results achieved by applications to EMS and Nordic currencies are not specific to data of target zone currencies. For example, application to US dollar and even to most unit root processes leads qualitatively to the same. This paper explores the solutions of this puzzle and shows a model of target zones in which the exchange rate within the band is not necessarily predictable since the process might follow chaotic dynamics before devaluation.
Resumo:
A szerz az alkalmazott tbbszektoros modellezs terletn a lineris programozsi modellektl a szmszerstett ltalnos egyenslyi modellekig vgbement vltozsokat tekinti t. Egy rvid trtneti visszapillants utn a lineris programozs mdszereire pl nemzetgazdasgi szint modellekkel sszevetve mutatja be az ltalnos egyenslyi modellek kzs, illetve eltr jellemzit. Egyidejleg azt is rzkelteti, hogyan lehet az ltalnos egyenslyi modelleket a gazdasgpolitikai clok konzisztencijnak, a clok kztti tvltsi lehetsgek elemzsre s ltalban a gazdasgpolitikai elkpzelsek rzkenysgi vizsglatra felhasznlni. A szerz az elmleti-mdszertani krdsek taglalst szmszerstett ltalnos egyenslyi modell segtsgvel illusztrlja. _______ The author surveys the changes having taken place in the field of multi-sector modeling, from the linear programming models to the quantified general equilibrium models. After a brief historical retrospection he presents the common and different characteristic features of the general equilibrium models by comparing them with the national economic level models based on the methods of linear programming. He also makes clear how the general equilibrium models can be used for analysing the consistency of economic policy targets, for the investigation of trade-off possibilities among the targets and, in general, for sensitivity analyses of economic policy targets. The discussion of theoretical and methodological quuestions is illustrated by the author with the aid of a quantified general equilibrium model.
Resumo:
Climate change has a great impact on the build and the work of natural ecosystems. Disappearance of some population or growth of the number in some species can be already caused by little change in temperature. A Theoretical Ecosystem Growth Model was investigated in order to examine the effects of various climate patterns on the ecological equilibrium. The answers of the ecosystems which are given to the climate change could be described by means of global climate modelling and dynamic vegetation models. The examination of the operation of the ecosystems is only possible in huge centres on supercomputers because of the number and the complexity of the calculation. The number of the calculation could be decreased to the level of a PC by considering the temperature and the reproduction during the modelling of a theoretical ecosystem and several important theoretical questions could be answered.
Resumo:
A szerz a tisztn elmleti clokra kifejlesztett Neumann-modellt s a gyakorlati alkalmazsok cljra kifejlesztett Leontief-modellt veti ssze. A Neumann-modell s a Leontief-modell ves termelsi peridust felttelez, zrt, stacionrius vltozatnak hasonl matematikai struktrja azt a felttelezst sugallja, hogy az utbbi a Neumann-modell sajtos eseteknt rtelmezhet. Az egyes modellek kzgazdasgi tartalmt s feltevseit rszletesen kibontva s egymssal sszevetve a szerz megmutatja, hogy a fenti kvetkeztets flrevezet, kt merben klnbz modellrl van sz, nem lehet az egyikbl a msikat levezetni. Az ikertermels s technolgiai vlasztk lehetsge a Neumann-modell elengedhetetlen feltevse, az ves termelsi peridus feltevse pedig kizrja folyam jelleg kibocstsok explicit figyelembevtelt. Mindezek feltevsek ugyanakkor idegenek a Leontief-modelltl. A kt modell valjban egy ltalnosabb llomnyfolyam jelleg zrt, stacionrius modell sajtos esete, mghozz azok folyamvltozkra reduklt alakja. _____ The paper compares the basic assumptions and methodology of the Von Neumann model, developed for purely abstract theoretical purposes, and those of the Leontief model, designed originally for practical applications. Study of the similar mathematical structures of the Von Neumann model and the closed, stationary Leontief model, with a unit length of production period, often leads to the false conclusion that the latter is just a simplified version of the former. It is argued that the economic assumptions of the two models are quite different, which makes such an assertion unfounded. Technical choice and joint production are indispensable features of the Von Neumann model, and the assumption of unitary length of production period excludes the possibility of taking service flows explicitly into account. All these features are completely alien to the Leontief model, however. It is shown that the two models are in fact special cases of a more general stock-flow stationary model, reduced to forms containing only flow variables.
Resumo:
Literature describing the notion and practice of business models has grown considerably over the last few years. Innovative business models appear in every sector of the economy challenging traditional ways of creating and capturing value. However, research describing the theoretical foundations of the field is scarce and many questions still remain. This article examines business models promoting various aspects of sustainable development and tests the explanatory power of two theoretical approaches, namely the resource based view of the firm and transaction cost theory regarding their emergence and successful market performance. Through the examples of industrial ecology and the sharing economy the author shows that a sharp reduction of transaction costs (e.g. in the form of internet based systems) coupled with resources widely available but not utilised before may result in fast growing new markets. This research also provides evidence regarding the notion that these two theoretical approaches can complement each other in explaining corporate behaviour.
