To elucidate the factors that affect the performance of plants in their natural environment, it is essential to study interactions with other neighboring plants, as well as with above- and belowground higher trophic organisms. We used a long-term field experiment to study how local plant community diversity influenced colonization by the biennial composite Senecio jacobaea in its native range i...

This paper considers a multi-objective portfolio selection problem imposed by gaining of portfolio, divided yield and risk control in an ambiguous investment environment, in which the return and risk are characterized by probabilistic numbers. Based on the theory of possibility, a new multi-objective portfolio optimization model with gaining of portfolio, divided yield and risk control is propo...

This study was conducted to compare the methods of seed bedpreparation in rangelands of Khash region in Sistan and Baluchestan province inIran. A split plot design was conducted based on Randomized complete blockdesign with three replications in 1999. Five seed bed preparation methods wereused as main plot as: 1) Seed sown by passing livestock. 2) Seed sown machinery.3) Seeds sown as drilled in...

due to project evaluation complexity and resource constraints, the project portfolio optimization is numerous decision making challenges. hence, many researches have been done to introduce model and methods for portfolio optimization. but most of them have not considered the interaction between projects. considering the interactions between projects increase complexity of portfolio optimization...

financial derivatives are new instruments through which hedging, investment and arbitrage are done in a modern economy. although the word 'derivative'primarily reminds us of options and futures, the major focus of the equity derivatives industry worldwide is on index derivatives. launching index options and index futures in tehran stock exchange, not only increases financial market de...

index tracking is the process of developing a portfolio that reproduces the performance of an index. the tracker portfolio has relatively good diversity and low turnover and low transaction costs. in this paper we applied a binary programming model for index tracking problem. in this model the number of assets for portfolio construction is defined by portfolio manager. the robust optimization f...

criteria in household portfolio. to do this, the data which are related to the asset price are used including: bank deposit, bonds, stock, exchange, coin, land and housing in time period of 1997 to 2011. in this research, portfolio var id calculated in the confidence level of 90%, 95%, and 99% and in time periods of one year and 14 years. after calculating returns, return standard deviation, co...

Projects scheduling by the project portfolio selection, something that has its own complexity and its flexibility, can create different composition of the project portfolio. An integer programming model is formulated for the project portfolio selection and scheduling.Two heuristic algorithms, genetic algorithm (GA) and simulated annealing (SA), are presented to solve the problem. Results of cal...

In the portfolio selection problem, the manager considers several objectives simultaneously such as the rate of return, the liquidity and the risk of portfolios. These objectives are conflicting and incommensurable. Moreover, the objectives can be imprecise. Generally, the portfolio manager seeks the best combination of the stocks that meets his investment objectives. The imprecise Goal Program...

abstract portfolio definition is the most important decision for individuals and legal persons that invest in stock. the main objective of this paper is study and determination of optimal portfolio for stock of active food industrial company in tehran stock based on value at risk (var) index. for this purpose, we used weekly static of stock of active food industrial company in tehran from bahma...