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Kim D.,University of Texas at Dallas | Brown Z.,North Carolina State University | Anderson R.,University of Washington | Mutero C.,Africa International University | And 3 more authors.
Risk Analysis | Year: 2016

Decision analysis tools and mathematical modeling are increasingly emphasized in malaria control programs worldwide to improve resource allocation and address ongoing challenges with sustainability. However, such tools require substantial scientific evidence, which is costly to acquire. The value of information (VOI) has been proposed as a metric for gauging the value of reduced model uncertainty. We apply this concept to an evidenced-based Malaria Decision Analysis Support Tool (MDAST) designed for application in East Africa. In developing MDAST, substantial gaps in the scientific evidence base were identified regarding insecticide resistance in malaria vector control and the effectiveness of alternative mosquito control approaches, including larviciding. We identify four entomological parameters in the model (two for insecticide resistance and two for larviciding) that involve high levels of uncertainty and to which outputs in MDAST are sensitive. We estimate and compare a VOI for combinations of these parameters in evaluating three policy alternatives relative to a status quo policy. We find having perfect information on the uncertain parameters could improve program net benefits by up to 5-21%, with the highest VOI associated with jointly eliminating uncertainty about reproductive speed of malaria-transmitting mosquitoes and initial efficacy of larviciding at reducing the emergence of new adult mosquitoes. Future research on parameter uncertainty in decision analysis of malaria control policy should investigate the VOI with respect to other aspects of malaria transmission (such as antimalarial resistance), the costs of reducing uncertainty in these parameters, and the extent to which imperfect information about these parameters can improve payoffs. © 2016 Society for Risk Analysis. Source

Osman A.H.,University of Technology Malaysia | Salim N.,Africa International University | Elhadi A.A.E.,University of Technology Malaysia
Proceedings - 2013 International Conference on Computer, Electrical and Electronics Engineering: 'Research Makes a Difference', ICCEEE 2013 | Year: 2013

This paper discusses a new plagiarism detection method for text documents called Tree-based Conceptual Matching. The proposed method not only represents the content of a text document as a tree, but it also captured the underlying semantic meaning in terms of the relationships among its concepts. The method was adopted to detect plagiarism in text documents. The tree-based played a very important role in this method. It looked at the amount of detecting plagiarized sentences from the original documents. Experiments have been carried out using the CS11 standard plagiarism detection corpus. The results were evaluated using information retrieval measurements, which are Recall, Precision and F-measure. The results were compared with other methods for plagiarism detection and we found our method outperforms the other methods for plagiarism detection. © 2013 IEEE. Source

Abubakar A.,University of Tilburg | Abubakar A.,University Utrecht | Alonso-Arbiol I.,University of the Basque Country | Van de Vijver F.J.R.,University of Tilburg | And 3 more authors.
Journal of Adolescence | Year: 2013

The current study is aimed at evaluating the relationship between attachment and identity development, and their influence on psychological well-being in adolescents with and without disabilities in Kenya. The sample was composed of 296 adolescents (151 with disabilities and 145 without any disability). The mean age in our sample was 16.84 years (SD=1.75). Adolescents with disabilities had significantly lower scores in identity formation, paternal attachment, and life satisfaction. A path model indicated that identity formation partially mediated the relationship between secure attachment and psychological well-being. Our findings indicate that both parent and peer attachment play an important role in the identity formation and psychological well-being of adolescents in Kenya, irrespective of a disabling condition. A multigroup analysis indicated that while the structure of the relationship between variables held for groups, the pattern and strength of the relationships differed. Implications for practice, especially the guidance and counseling services in schools, are discussed. © 2013 The Foundation for Professionals in Services for Adolescents. Source

Khamis S.A.,Africa International University | Tchuenche J.M.,University of Dar es Salaam | Lukka M.,Lappeenranta University of Technology | Heilio M.,Lappeenranta University of Technology
International Journal of Computer Mathematics | Year: 2011

A model for two fish species and one predator in a patchy environment is formulated using a deterministic model to study the dynamics of fishery in two homogeneous patches, a free fishing zone and a refuge for prey reserve in which fishing is prohibited. The system is analysed around steady states; the criteria for local and global stabilities are established. The existence of bionomic equilibrium of the system is determined and the conditions for their existence are derived. The optimal harvesting policy is studied by using Pontryagin's maximal principle. Sensitivity analysis is carried out and it is observed that the populations are more sensitive to growth, dispersal and predation rates, least sensitive to the catchability coefficient. Statistical analysis is employed to estimate the parameters and to assess both the uncertainty in the model parameters and in the model-based predictions. Graphical representations of the model are provided. © 2011 Taylor & Francis. Source

Tchuenche J.M.,University of Dar es Salaam | Khamis S.A.,Africa International University | Agusto F.B.,Federal University of Technology Akurre | Mpeshe S.C.,P.A. College
Acta Biotheoretica | Year: 2011

We formulate and analyze the dynamics of an influenza pandemic model with vaccination and treatment using two preventive scenarios: increase and decrease in vaccine uptake. Due to the seasonality of the influenza pandemic, the dynamics is studied in a finite time interval. We focus primarily on controlling the disease with a possible minimal cost and side effects using control theory which is therefore applied via the Pontryagin's maximum principle, and it is observed that full treatment effort should be given while increasing vaccination at the onset of the outbreak. Next, sensitivity analysis and simulations (using the fourth order Runge-Kutta scheme) are carried out in order to determine the relative importance of different factors responsible for disease transmission and prevalence. The most sensitive parameter of the various reproductive numbers apart from the death rate is the inflow rate, while the proportion of new recruits and the vaccine efficacy are the most sensitive parameters for the endemic equilibrium point. © 2010 Springer Science+Business Media B.V. Source

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