Modern financial theory, commonly known as portfolio theory, provides an analytical framework for the investment decision to be made under uncertainty. It is a well-established proposition in portfolio theory that whe...Modern financial theory, commonly known as portfolio theory, provides an analytical framework for the investment decision to be made under uncertainty. It is a well-established proposition in portfolio theory that whenever there is an imperfect correlation between returns risk is reduced by maintaining only a portion of wealth in any asset, or by selecting a portfolio according to expected returns and correlations between returns. The major improvement of the portfolio approaches over prior received theory is the incorporation of 1) the riskiness of an asset and 2) the addition from investing in any asset. The theme of this paper is to discuss how to propose a new mathematical model like that provided by Markowitz, which helps in choosing a nearly perfect portfolio and an efficient input/output. Besides applying this model to reality, the researcher uses game theory, stochastic and linear programming to provide the model proposed and then uses this model to select a perfect portfolio in the Cairo Stock Exchange. The results are fruitful and the researcher considers this model a new contribution to previous models.展开更多
A modified model of optimal investment port folio in a random market with risk constraints is presented. An improved genetic algorithm (GA) is proposed to solve this nonlinear optimal problem. The numerical simulation...A modified model of optimal investment port folio in a random market with risk constraints is presented. An improved genetic algorithm (GA) is proposed to solve this nonlinear optimal problem. The numerical simulation of a large-scale investment combination for Shanghai stock market shows that GA has the advantage of faster convergence and wider adaptability than traditional optimization algorithm. This result alsodemonstrates that the improved GA performs better than the basic GA.展开更多
In this paper, from the viewpoint of the time value of money, we study the risk measures for portfolio vectors with discount factor. Cash subadditive risk measures for portfolio vectors are proposed. Representation re...In this paper, from the viewpoint of the time value of money, we study the risk measures for portfolio vectors with discount factor. Cash subadditive risk measures for portfolio vectors are proposed. Representation results are given by two different methods which are convex analysis and enlarging space. Especially, the method of convex analysis make the line of reasoning and the representation result be simpler. Meanwhile, spot and forward risk measures for portfolio vectors are also introduced, and the relationships between them are investigated.展开更多
In order to study the effect of different risk measures on the efficient portfolios （fron- tier） while properly describing the characteristic of return distributions in the stock market, it is assumed in this paper ...In order to study the effect of different risk measures on the efficient portfolios （fron- tier） while properly describing the characteristic of return distributions in the stock market, it is assumed in this paper that the joint return distribution of risky assets obeys the multivariate t-distribution. Under the mean-risk analysis framework, the interrelationship of efficient portfolios （frontier） based on risk measures such as variance, value at risk （VaR）, and expected shortfall （ES） is analyzed and compared. It is proved that, when there is no riskless asset in the market, the efficient frontier under VaR or ES is a subset of the mean-variance （MV） efficient frontier, and the efficient portfolios under VaR or ES are also MV efficient; when there exists a riskless asset in the market, a portfolio is MV efficient if and only if it is a VaR or ES efficient portfolio. The obtained results generalize relevant conclusions about investment theory, and can better guide investors to make their investment decision.展开更多
This work focuses on the best financial resources allocation to define a wind power plant portfolio, considering a set of feasible sites. To accomplish the problem formulation and solution, the first step was to estab...This work focuses on the best financial resources allocation to define a wind power plant portfolio, considering a set of feasible sites. To accomplish the problem formulation and solution, the first step was to establish a long-term wind series reconstruction methodology for generating scenarios of wind energy, applying it to study five different locations of the Brazilian territory. Secondly, a risk-averse stochastic optimization model was implemented and used to define the optimal wind power plant selection </span><span style="font-family:Verdana;">that</span><span style="font-family:Verdana;"> maximize</span><span style="font-family:Verdana;">s</span><span style="font-family:Verdana;"> the portfolio financial results, considering an investment budget constraint. In a sequence, a case study was developed to illustrate a practical situation of applying the methodology to the portfolio selection problem, considering five wind power plant</span><span style="font-family:Verdana;">s</span><span style="font-family:Verdana;"> options. </span><span style="font-family:Verdana;">The case</span><span style="font-family:Verdana;"> study was supported by the proposed optimization model, using the scenarios of generation created by the reconstruction methodology. The obtained results show the model performance in terms of defining the best financial resources allocation considering the effect of the complementarity between sites, making it feasible to select the optimal set of wind power plants, characterizing a wind plant optimal portfolio that takes into account the budget constraint. The adopted methodology makes it possible to realize that the diversification of the portfolio depends on the investor risk aversion. Although applied to the Brazilian case, this model can be customized to solve a similar problem worldwide.展开更多
Aim of this paper is to characterize different risk measures in portfolio construction on seven Central and South-East European stock markets;Slovenia, Croatia, Hungary, Poland, Chez Republic, Bulgaria and Romania. Se...Aim of this paper is to characterize different risk measures in portfolio construction on seven Central and South-East European stock markets;Slovenia, Croatia, Hungary, Poland, Chez Republic, Bulgaria and Romania. Selected countries are members of EU, except Croatia and Turkey which have candidate status. Empirical part of this paper consists of three stages;at first descriptive statistic on stock returns was performed, afterwards different risk measures were employed in portfolio construction and in the last part, portfolios were tested in the out-of-sample period. Results indicate presence of extreme kurtosis and skewness in stock return series. Resulting portfolios incorporate stocks with extremely high kurtosis and stocks with negative skewness. Portfolio construction based only on risk and return results in major exposure to extreme returns and unsatisfactory portfolio out of sample results.展开更多
For oil company decision-makers,the principal concern is how to allocate their limited resources into the most valuable opportunities.Recently a new management philosophy,＂Beyond NPV＂,has received more and more inte...For oil company decision-makers,the principal concern is how to allocate their limited resources into the most valuable opportunities.Recently a new management philosophy,＂Beyond NPV＂,has received more and more international attention.Economists and senior executives are seeking effective alternative analysis approaches for traditional technical and economic evaluation methods.The improved portfolio optimization model presented in this article represents an applicable technique beyond NPV for doing capital budgeting.In this proposed model,not only can oil company executives achieve trade-offs between returns and risks to their risk tolerance,but they can also employ an ＂operational premium＂ to distinguish their ability to improve the performance of the underlying projects.A simulation study based on 19 overseas upstream assets owned by a large oil company in China is conducted to compare optimized utility with non-optimized utility.The simulation results show that the petroleum optimization model including ＂operational premium＂ is more in line with the rational investors＇ demand.展开更多
Dams are critical and essential elements in any infrastructure and, in front of accidents occurred in many countries, it is extremely important to know the risk of these structures. Inserted in this context, it was fo...Dams are critical and essential elements in any infrastructure and, in front of accidents occurred in many countries, it is extremely important to know the risk of these structures. Inserted in this context, it was found in the technical literature, methods and tools capable of measuring the exposure value by means of indicators. In the study, the highlights were 12 methods of qualitative, semiquantitative and quantitative risk analysis, representing an overview of risk analysis methods available in the literature with potential use in dams, that it has been done into electronic spreadsheets. The case study is performed on a sample of concrete dam and earth/rockfill built and operated by Eletrobr^s Furnas Company, supported by documentary research, projects, field inspections and interviews with experts. After applying the methods and the analysis thereof, has been prepared the Eletrobras Fumas dam risk analysis method which is characterized by adapting the criteria analyzed to the reality of the company＇s dams and it was also performed the portfolio risk analysis of 18 dams. In spite of the variety and subjectivity of qualitative and semiquantitative methods, the results show that they tend to converge on the analysis of dam based on risk. The application methodology demonstrates the feasibility assessment stage, covering the preliminary analysis for portfolio dams, followed by formal and individual risk analyzes for the most critical structures. These results confirm the applicability of risk analysis techniques, contributing to the consolidation of this toot as fundamental in the dam safety.展开更多
文摘Modern financial theory, commonly known as portfolio theory, provides an analytical framework for the investment decision to be made under uncertainty. It is a well-established proposition in portfolio theory that whenever there is an imperfect correlation between returns risk is reduced by maintaining only a portion of wealth in any asset, or by selecting a portfolio according to expected returns and correlations between returns. The major improvement of the portfolio approaches over prior received theory is the incorporation of 1) the riskiness of an asset and 2) the addition from investing in any asset. The theme of this paper is to discuss how to propose a new mathematical model like that provided by Markowitz, which helps in choosing a nearly perfect portfolio and an efficient input/output. Besides applying this model to reality, the researcher uses game theory, stochastic and linear programming to provide the model proposed and then uses this model to select a perfect portfolio in the Cairo Stock Exchange. The results are fruitful and the researcher considers this model a new contribution to previous models.
文摘A modified model of optimal investment port folio in a random market with risk constraints is presented. An improved genetic algorithm (GA) is proposed to solve this nonlinear optimal problem. The numerical simulation of a large-scale investment combination for Shanghai stock market shows that GA has the advantage of faster convergence and wider adaptability than traditional optimization algorithm. This result alsodemonstrates that the improved GA performs better than the basic GA.
基金Supported by the National Natural Science Foundation of China(11371284,11771343)
文摘In this paper, from the viewpoint of the time value of money, we study the risk measures for portfolio vectors with discount factor. Cash subadditive risk measures for portfolio vectors are proposed. Representation results are given by two different methods which are convex analysis and enlarging space. Especially, the method of convex analysis make the line of reasoning and the representation result be simpler. Meanwhile, spot and forward risk measures for portfolio vectors are also introduced, and the relationships between them are investigated.
基金Supported by the NNSF of China (10571141) the Key Project of the NNSF of China (70531030).
文摘In order to study the effect of different risk measures on the efficient portfolios （fron- tier） while properly describing the characteristic of return distributions in the stock market, it is assumed in this paper that the joint return distribution of risky assets obeys the multivariate t-distribution. Under the mean-risk analysis framework, the interrelationship of efficient portfolios （frontier） based on risk measures such as variance, value at risk （VaR）, and expected shortfall （ES） is analyzed and compared. It is proved that, when there is no riskless asset in the market, the efficient frontier under VaR or ES is a subset of the mean-variance （MV） efficient frontier, and the efficient portfolios under VaR or ES are also MV efficient; when there exists a riskless asset in the market, a portfolio is MV efficient if and only if it is a VaR or ES efficient portfolio. The obtained results generalize relevant conclusions about investment theory, and can better guide investors to make their investment decision.
文摘This work focuses on the best financial resources allocation to define a wind power plant portfolio, considering a set of feasible sites. To accomplish the problem formulation and solution, the first step was to establish a long-term wind series reconstruction methodology for generating scenarios of wind energy, applying it to study five different locations of the Brazilian territory. Secondly, a risk-averse stochastic optimization model was implemented and used to define the optimal wind power plant selection </span><span style="font-family:Verdana;">that</span><span style="font-family:Verdana;"> maximize</span><span style="font-family:Verdana;">s</span><span style="font-family:Verdana;"> the portfolio financial results, considering an investment budget constraint. In a sequence, a case study was developed to illustrate a practical situation of applying the methodology to the portfolio selection problem, considering five wind power plant</span><span style="font-family:Verdana;">s</span><span style="font-family:Verdana;"> options. </span><span style="font-family:Verdana;">The case</span><span style="font-family:Verdana;"> study was supported by the proposed optimization model, using the scenarios of generation created by the reconstruction methodology. The obtained results show the model performance in terms of defining the best financial resources allocation considering the effect of the complementarity between sites, making it feasible to select the optimal set of wind power plants, characterizing a wind plant optimal portfolio that takes into account the budget constraint. The adopted methodology makes it possible to realize that the diversification of the portfolio depends on the investor risk aversion. Although applied to the Brazilian case, this model can be customized to solve a similar problem worldwide.
基金Supported by National Natural Science Foundation of China （10671112）, National Basic Research Program of China （973 Program） （2007CB814904）, the Natural Science Foundation of Shandong Province （Z2006A01）, and the Chinese New Century Young Teachers Program The authors would like to thank the referees for a careful reading of this paper and helpful suggestions which made the revised version more readable.
文摘Aim of this paper is to characterize different risk measures in portfolio construction on seven Central and South-East European stock markets;Slovenia, Croatia, Hungary, Poland, Chez Republic, Bulgaria and Romania. Selected countries are members of EU, except Croatia and Turkey which have candidate status. Empirical part of this paper consists of three stages;at first descriptive statistic on stock returns was performed, afterwards different risk measures were employed in portfolio construction and in the last part, portfolios were tested in the out-of-sample period. Results indicate presence of extreme kurtosis and skewness in stock return series. Resulting portfolios incorporate stocks with extremely high kurtosis and stocks with negative skewness. Portfolio construction based only on risk and return results in major exposure to extreme returns and unsatisfactory portfolio out of sample results.
基金financial support from National Science and Technology Major Project of the Ministry of Science and Technology of China"Research on Investment estimation tools and economic appraisal system integration and development"(2011ZX05030-006-04)
文摘For oil company decision-makers,the principal concern is how to allocate their limited resources into the most valuable opportunities.Recently a new management philosophy,＂Beyond NPV＂,has received more and more international attention.Economists and senior executives are seeking effective alternative analysis approaches for traditional technical and economic evaluation methods.The improved portfolio optimization model presented in this article represents an applicable technique beyond NPV for doing capital budgeting.In this proposed model,not only can oil company executives achieve trade-offs between returns and risks to their risk tolerance,but they can also employ an ＂operational premium＂ to distinguish their ability to improve the performance of the underlying projects.A simulation study based on 19 overseas upstream assets owned by a large oil company in China is conducted to compare optimized utility with non-optimized utility.The simulation results show that the petroleum optimization model including ＂operational premium＂ is more in line with the rational investors＇ demand.
文摘Dams are critical and essential elements in any infrastructure and, in front of accidents occurred in many countries, it is extremely important to know the risk of these structures. Inserted in this context, it was found in the technical literature, methods and tools capable of measuring the exposure value by means of indicators. In the study, the highlights were 12 methods of qualitative, semiquantitative and quantitative risk analysis, representing an overview of risk analysis methods available in the literature with potential use in dams, that it has been done into electronic spreadsheets. The case study is performed on a sample of concrete dam and earth/rockfill built and operated by Eletrobr^s Furnas Company, supported by documentary research, projects, field inspections and interviews with experts. After applying the methods and the analysis thereof, has been prepared the Eletrobras Fumas dam risk analysis method which is characterized by adapting the criteria analyzed to the reality of the company＇s dams and it was also performed the portfolio risk analysis of 18 dams. In spite of the variety and subjectivity of qualitative and semiquantitative methods, the results show that they tend to converge on the analysis of dam based on risk. The application methodology demonstrates the feasibility assessment stage, covering the preliminary analysis for portfolio dams, followed by formal and individual risk analyzes for the most critical structures. These results confirm the applicability of risk analysis techniques, contributing to the consolidation of this toot as fundamental in the dam safety.
