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| Registros recuperados: 179 | |
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| Hoe, Lam Weng; Saiful Hafizah, Jaaman; Zaidi, Isa. |
| Risk is one of the important parameters in portfolio optimization problem. Since the introduction of the mean-variance model, variance has become the most common risk measure used by practitioners and researchers in portfolio optimization. However, the mean-variance model relies strictly on the assumptions that assets returns are multivariate normally distributed or investors have a quadratic utility function. Many studies have proposed different risk measures to overcome the drawbacks of variance. The purpose of this paper is to discuss and compare the portfolio compositions and performances of four different portfolio optimization models employing different risk measures, specifically the variance, absolute deviation, minimax and semi-variance. Results... |
| Tipo: Journal Article |
Palavras-chave: Portfolio; Optimization; Risk measures; Variance.; Financial Economics; CO2; C61; G11. |
| Ano: 2010 |
URL: http://purl.umn.edu/95934 |
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| Valin, Hugo; Havlik, Petr; Mosnier, Aline; Obersteiner, Michael. |
| Discussions on climate change increasingly emphasize the contribution of agricultural activities to anthropogenic greenhouse gases emissions. In this paper, we investigate from a supply to demand side perspective the stress between food demand and climate change challenges up until 2030. We examine how more stringent climate change mitigation policies could alter agricultural markets and put at risk the nutrition possibilities of populations. We use for this purpose GLOBIOM, an applied partial equilibrium model covering, at the world scale and a fine grid resolution, the main land-based sectors: agriculture, forestry and bioenergy. For this exercise, the model is fully linked to a semi-flexible endogenous demand system with non-linear Engel’s curves. Our... |
| Tipo: Conference Paper or Presentation |
Palavras-chave: Agricultural and Food Policy; Consumer/Household Economics; Demand and Price Analysis; Food Consumption/Nutrition/Food Safety; Food Security and Poverty; Health Economics and Policy; C61; Q11; Q24; Q54. |
| Ano: 2010 |
URL: http://purl.umn.edu/116392 |
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| Efstratoglou, Sophia; Giannakis, Elias; Psaltopoulos, Dimitrios. |
| Current considerations for the post-2013 CAP create the need for the investigation and evaluation of alternative CAP scenarios and their effects on agriculture, environment and regional development in EU rural areas. To this end, a system-dynamics model is developed and utilized to evaluate the impacts of alternative CAP scenarios in a Greek rural area (prefecture of Trikala). This particular model features four basic subsystems (agriculture, environment, regional economy and human resources) specified and analyzed through a linear programming model, a dynamic input-output model and an age-cohort demographic model, respectively. Four alternative policy scenarios are specified, dealing with possible developments on Pillars 1 and 2. Model simulations produce... |
| Tipo: Conference Paper or Presentation |
Palavras-chave: CAP; Policy impact assessment; Rural development; System dynamics; Agricultural and Food Policy; C61; C67; Q18; R58. |
| Ano: 2011 |
URL: http://purl.umn.edu/99361 |
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| Gocht, Alexander; Roder, Norbert. |
| In Germany, since several decades the RAUMIS modelling system is applied for policy impact assessments to measure the impact of agriculture on the environment. A disaggregation at the municipality level with more than 9.600 administrative units, instead of currently used 316 counties, would tremendously improve the environmental impact analysis. Two sets of data are used for this purpose. The first are geo-referenced data, that are, however, incomplete with respect its coverage of production activities in agriculture. The second set is the micro census statistic itself, that has a full coverage, but data protection rules (DPR) prohibit its straightforward use. The paper show how this bottleneck can be passed to obtain a reliable modelling data set at... |
| Tipo: Conference Paper or Presentation |
Palavras-chave: Highest Posterior Density estimator (HPD); RAUMIS; Down scaling; Research Methods/ Statistical Methods; C11; C61; C81; Q15. |
| Ano: 2011 |
URL: http://purl.umn.edu/115982 |
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| Gocht, Alexander; Roder, Norbert. |
| In Germany, since several decades the RAUMIS modelling system is applied for policy impact assessments to measure the impact of agriculture on the environment. A disaggregation at the municipality level with more than 9.600 administrative units, instead of currently used 316 counties, would tremendously improve the environmental impact analysis. Two sets of data are used for this purpose. The first are geo-referenced data, that are, however, incomplete with respect its coverage of production activities in agriculture. The second set is the micro census statistic itself, that has a full coverage, but data protection rules (DPR) prohibit its straightforward use. The paper show how this bottleneck can be passed to obtain a reliable modelling data set at... |
| Tipo: Conference Paper or Presentation |
Palavras-chave: Highest Posterior Density estimator (HPD); RAUMIS; Down scaling; Research Methods/ Statistical Methods; C11; C61; C81; Q15. |
| Ano: 2011 |
URL: http://purl.umn.edu/114824 |
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| Tsur, Yacov. |
| We study water regulation for a schematic water economy representing a wide range of real world situations. A water policy has inter- and intra-temporal components. The first determines the limits on extractions from the naturally replenished sources, given the stochastic nature of recharge processes associated with uncertain precipitation. The intra-temporal regulation is concerned mainly with the allocating of the extracted and produced water among the end-users. The prices that implement the optimal intra-temporal allocation are derived. Regulation issues associated with cost recovery and asymmetric information are discussed. |
| Tipo: Working or Discussion Paper |
Palavras-chave: Scarcity; Pricing; Optimal allocation; Water economy; Resource /Energy Economics and Policy; C61; D82; Q11; Q25. |
| Ano: 2009 |
URL: http://purl.umn.edu/47173 |
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| Krcmar, Emina; Eagle, Alison J.; van Kooten, G. Cornelis. |
| In Canada, governments have historically promoted economic development in rural regions by promoting exploitation of natural resources, particularly forests. Forest resources are an economic development driver in many of the more than 80% of native communities located in forest regions. But forests also provide aboriginal people with cultural and spiritual values, and non-timber forest amenities (e.g., biodiversity, wildlife harvests for meat and fur, etc.), that are incompatible with timber exploitation. Some cultural and other amenities can only be satisfied by maintaining a certain amount of timber in an old-growth state. In that case, resource constraints might be too onerous to satisfy development needs. We employ compromise programming and fuzzy... |
| Tipo: Conference Paper or Presentation |
Palavras-chave: Forest-dependent aboriginal communities; Boreal forest; Compromise and fuzzy programming; Sustainability and uncertainty; International Development; Resource /Energy Economics and Policy; R11; Q23; Q01; C61. |
| Ano: 2007 |
URL: http://purl.umn.edu/10251 |
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| Prescott, Ryan; van Kooten, G. Cornelis. |
| In this paper, we examine the impact policy choices, including a carbon tax, on the optimal allocation of power across different generation sources and on future investments in generating facilities. The focus in on the Alberta power grid as it is heavily dependent on fossil fuels and has only limited ties to other power grids, although the model could be extended to a larger and even multiple grids. Results indicate that, as wind penetrates the extant generating mix characterizing the grid, cost savings and emission reductions do not decline linearly, but at a decreasing rate. However, if flexibility is allowed then, as the carbon tax increases to $40 per tCO2 or above, existing coal plants start to be replaced by newly constructed wind farms and natural... |
| Tipo: Working or Discussion Paper |
Palavras-chave: Economics of wind power; Grid system modeling; Operations research; Carbon taxes; Coal power plants; Environmental Economics and Policy; Resource /Energy Economics and Policy; C61; H23; Q40; Q42. |
| Ano: 2007 |
URL: http://purl.umn.edu/37043 |
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| Albisser, Gregor. |
| As a consequence of the reorientation of the Swiss as well as the European agricultural policy, prices for agricultural products drop and farmers have to reduce their production costs or will lose income. Therefore a lot of farmers have a high incentive to change their production structures. One of the most effective strategies to reduce production costs is going into cooperation and collaboration with other farmers. Therewith farmers can profit from scale effects without changing the property rights. Several case studies as well as results from modeling reveal that farmers have more income with less workload. In reality only 3% of Swiss farmers have gone into a collective farming system. Weaker forms of cooperation like sharing machinery are more common... |
| Tipo: Conference Paper or Presentation |
Palavras-chave: Agent-based simulation; Structural change; Cooperation strategies; Collaboration; Agribusiness; Farm Management; C61; Q12; Q15. |
| Ano: 2007 |
URL: http://purl.umn.edu/6576 |
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| Michele, Moretto; Gianpaolo, Rossini. |
| The main aim of the paper is to highlight the relation between flexibility and vertical integration. To this purpose, we go through the selection of the optimal degree of vertical disintegration of a flexible firm which operates in a dynamic uncertain environment. The enterprise we model enjoys flexibility since it can switch from a certain amount of disintegration to vertical integration and viceversa. This means that the firm never loses vertical control, i.e., the ability to produce all inputs even when it buys them in the market. This sort of flexibility makes for results which are somehow contrary to the Industrial Organization recent literature and closer to the Operations Research results. In this sense we provide a bridge between the two approaches... |
| Tipo: Working or Discussion Paper |
Palavras-chave: Vertical Integration; Outsourcing; Entry; Flexibility; L24; G 31; C61. |
| Ano: 2008 |
URL: http://purl.umn.edu/36759 |
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| Registros recuperados: 179 | |
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