89 research outputs found

    Kibera Community Unconscious of the Silent Disease: STI

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    The objective of this study was to conduct a Sexually Transmitted Infections (STI) Awareness Survey that explores knowledge about STIs and attitude towards them, and thereafter, institute and implement an educational intervention in the Kibera slum, of Nairobi. The survey included 120 participants from the 12 villages of Kibera. It revealed that, of those interviewed, 34% are unable to name an STI other than HIV/AIDS and 99% are unaware of any of the syndromes associated with STIs. This demonstrated a clear need for STI Awareness and education, and thus an informative brochure on STIs was created, to be distributed during Outreach Programs and at the Tabitha Clinic in Kibera

    Virtual Socializing: Its Motives and Spread

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    Virtual communities constitute an important attribute through which social dialogues are mediated. The emergence of online communities is the outcome of the prevalence of web based technologies. In the world of inter and intra connectedness individuals have the prerogative to get connected to the community of their choice. The present study examines the magnitude and motivations of online social networking through field survey method.virtual socializing, online communities, social networking, virtual platforms, virtual communities

    Self-adaptive simulated binary crossover for real-parameter optimization

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    Simulated binary crossover (SBX) is a real-parameter recombinationoperator which is commonly used in the evolutionary algorithm (EA) literature. The operatorinvolves a parameter which dictates the spread of offspring solutionsvis-a-vis that of the parent solutions. In all applications of SBX sofar, researchers have kept a fixed value throughout a simulation run. In this paper, we suggest a self-adaptive procedure of updating theparameter so as to allow a smooth navigation over the functionlandscape with iteration. Some basic principles of classicaloptimization literature are utilized for this purpose. The resultingEAs are found to produce remarkable and much better results comparedto the original operator having a fixed value of the parameter. Studieson both single and multiple objective optimization problems are madewith success

    A survey on handling computationally expensive multiobjective optimization problems with evolutionary algorithms

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    This is the author accepted manuscript. The final version is available from Springer Verlag via the DOI in this record.Evolutionary algorithms are widely used for solving multiobjective optimization problems but are often criticized because of a large number of function evaluations needed. Approximations, especially function approximations, also referred to as surrogates or metamodels are commonly used in the literature to reduce the computation time. This paper presents a survey of 45 different recent algorithms proposed in the literature between 2008 and 2016 to handle computationally expensive multiobjective optimization problems. Several algorithms are discussed based on what kind of an approximation such as problem, function or fitness approximation they use. Most emphasis is given to function approximation-based algorithms. We also compare these algorithms based on different criteria such as metamodeling technique and evolutionary algorithm used, type and dimensions of the problem solved, handling constraints, training time and the type of evolution control. Furthermore, we identify and discuss some promising elements and major issues among algorithms in the literature related to using an approximation and numerical settings used. In addition, we discuss selecting an algorithm to solve a given computationally expensive multiobjective optimization problem based on the dimensions in both objective and decision spaces and the computation budget available.The research of Tinkle Chugh was funded by the COMAS Doctoral Program (at the University of Jyväskylä) and FiDiPro Project DeCoMo (funded by Tekes, the Finnish Funding Agency for Innovation), and the research of Dr. Karthik Sindhya was funded by SIMPRO project funded by Tekes as well as DeCoMo

    Hybridization of SBX based NSGA-II and sequential quadratic programming for solving multi-objective optimization problems

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    Most real-world search and optimization problems involve multiple conflicting objectives and results in a Pareto-optimal set. Various multi-objective optimization algorithms have been proposed for solving such problems with the goals of finding as many trade-off solutions as possible and maintaining diversity among them. Since last decade, evolutionary multi-objective optimization (EMO) algorithms have been applied successfully to various test and real-world optimization problems. These population based algorithms provide a diverse set of non-dominated solutions. The obtained non-dominated set is close to the true Pareto-optimal front but it's convergence to the true Pareto-optimal front is not guaranteed. Hence to ensure the same, a local search method using classical algorithm can be applied. In the present work, SBX based NSGA-II is used as a population based approach and the sequential quadratic programming (SQP) method is used as a local search procedure. This hybridization of evolutionary and classical algorithms approach provides a confidence of converging near to the true Pareto-optimal set with a good diversity. The proposed procedure is successfully applied to 13 test problems consisting two, three and five objectives. The obtained results validate our motivation of hybridizing evolutionary and classical methods

    Local search based evolutionary multi-objective optimization algorithm for constrained and unconstrained problems

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    Evolutionary multi-objective optimization algorithms are commonly used to obtain a set of non-dominated solutions for over a decade. Recently, a lot of emphasis have been laid on hybridizing evolutionary algorithms with MCDM and mathematical programming algorithms to yield a computationally efficient and convergent procedure. In this paper, we test an augmented local search based EMO procedure rigorously on a test suite of constrained and unconstrained multi-objective optimization problems. The success of our approach on most of the test problems not only provides confidence but also stresses the importance of hybrid evolutionary algorithms in solving multi-objective optimization problems

    Virtual Socializing: Its Motives and Spread

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    Virtual communities constitute an important attribute through which social dialogues are mediated. The emergence of online communities is the outcome of the prevalence of web based technologies. In the world of inter and intra connectedness individuals have the prerogative to get connected to the community of their choice. The present study examines the magnitude and motivations of online social networking through field survey method

    Virtual Socializing: Its Motives and Spread

    Get PDF
    Virtual communities constitute an important attribute through which social dialogues are mediated. The emergence of online communities is the outcome of the prevalence of web based technologies. In the world of inter and intra connectedness individuals have the prerogative to get connected to the community of their choice. The present study examines the magnitude and motivations of online social networking through field survey method

    A Fast Hypervolume Driven Selection Mechanism for Many-Objective Optimisation Problems.

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    Solutions to real-world problems often require the simultaneous optimisation of multiple conflicting objectives. In the presence of four or more objectives, the problem is referred to as a “many-objective optimisation problem”. A problem of this category introduces many challenges, one of which is the effective and efficient selection of optimal solutions. The hypervolume indicator (or s-metric), i.e. the size of dominated objective space, is an effective selection criterion for many-objective optimisation. The indicator is used to measure the quality of a nondominated set, and can be used to sort solutions for selection as part of the contributing hypervolume indicator. However, hypervolume based selection methods can have a very high, if not infeasible, computational cost. The present study proposes a novel hypervolume driven selection mechanism for many-objective problems, whilst maintaining a feasible computational cost. This approach, named the Hypervolume Adaptive Grid Algorithm (HAGA), uses two-phases (narrow and broad) to prevent population-wide calculation of the contributing hypervolume indicator. Instead, HAGA only calculates the contributing hypervolume indicator for grid populations, i.e. for a few solutions, which are close in proximity (in the objective space) to a candidate solution when in competition for survival. The result is a trade-off between complete accuracy in selecting the fittest individuals in regards to hypervolume quality, and a feasible computational time in many-objective space. The real-world efficiency of the proposed selection mechanism is demonstrated within the optimisation of a classifier for concealed weapon detection
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