Browsing by Author "Darko, Samuel"

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    Constructing optimal stock portfolio with Markowitz Model
    (2012-06-10) Darko, Samuel
    A portfolio is a collection of financial assets consisting of investment tools such as stocks, bonds, gold, foreign exchange, asset-backed securities, real estate certificates and bank deposit which are held by a person or a group of persons. In Ghana, constructing portfolio with standardized optimization model still remains a myth. In this paper, we analyze the applicability of the classical Markowitz model on the Ghana Stock Exchange. We further determine which Stock-index is profitable for an investor; thus should the investor invest in the GSE-All-Share Index, Non-financial Index, or the Financial Index given the current performance of the indices. Historical monthly data of stock prices, market capitalization and dividend per share from 2007 to 2010 were used to compute the market indices. The study concludes that it is profitable for an investor to invest 83.44% of his capital in the non-financial index while investing 16.56% in the financial index. We further conclude that the Ghanaian stock market obeys the tenet of the Markowitz model.
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    Optimal harvesting policy for an age-structured tilapia population
    (2012-06-29) Darko, Samuel
    This research was carried out to determine an efficient optimal sustainable harvesting policy for an age-structured tilapia population using the Leslie model. The population was grouped into three age classes of six months intervals: juvenile, matured and older classes. The dynamics of the population was investigated by finding the eigenvalues and eigenvectors of the Leslie matrix of the tilapia population and develop an optimal sustainable harvesting policy for the population. The dominant eigenvalue was and the corresponding eigenvector indicated that in long run the population will consist of 94% of the juveniles, 5.6% of matured and only 0.4% of the older fish. The optimal sustainable harvesting policy was harvesting 99.3% of the juveniles and all the older fish.