• Korean Journal of Microbiology
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• v.22 no.3
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• pp.191-195
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• 1984

In order to study on the pigment formation of Serratia marcescens, the synthesis of prodigiosin was examined in the presence of a wide range of concentration of detergents. A high elevation of pigment formation was obtained in case of the treatment with SDC and SAP. And the population growth of the bacteria was increased by SDC and SAP, in the concentration of optimum concentration of pigment formation. The alkaline phosphatase activity was also increased in the treatment of SAP, SDC and SDS. The possible mechanism of the detergents on enhancement of pigment formation could be explained by an increase of enzyme activity and membrane transport.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1999.10a
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• pp.301-308
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• 1999

This paper describes the application of genetic algorithm(GA) in the discrete optimal design of truss structures. Stochastic processes generate an intial population of design and then apply principles of natural selection/survival of the fittest to improve the design. GA is applied to minimum weight of truss subject to stress and displacement constraints under multiple loading conditions. First, optimum solutions obtained from GA are compared to verify the reliability of GA with m well-known transmission tower structure which is referred to by other authors. Then, discrete optimal design is performed in satisfying service conditions of truss structure with commercially available fabricated sizes. From the results, it is found that GA search technique is very effective for discrete optimal design of truss structure and has high robustness.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1997.10a
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• pp.155-162
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• 1997

Genetic algorithms(GA) are based on the principles of natural genetics and natural selection. The algorithm searches an optimum design point using information based on the fitness function evaluated for the population of many design points. An application of GA on optimal design of a truss structure is studied. The terminology and the operating procedures common in GA are formalized by establishing similarities between GA and genetics from biology. In using GA, (1) coding of the design variables, (2) formulation of the fitness function, (3) setting of the termination condition, and (4) establishment of the probabilities are essential. These four points are discussed in the paper.

• Smart Structures and Systems
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• v.15 no.3
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• pp.735-749
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• 2015

The major difficulty of using Bayesian probabilistic inference for system identification is to obtain the posterior probability density of parameters conditioned by the measured response. The posterior density of structural parameters indicates how plausible each model is when considering the uncertainty of prediction errors. The Markov chain Monte Carlo (MCMC) method is a widespread medium for posterior inference but its convergence is often slow. The differential evolution adaptive Metropolis-Hasting (DREAM) algorithm boasts a population-based mechanism, which nms multiple different Markov chains simultaneously, and a global optimum exploration ability. This paper proposes an improved differential evolution adaptive Metropolis-Hasting algorithm (IDREAM) strategy to estimate the posterior density of structural parameters. The main benefit of IDREAM is its efficient MCMC simulation through its use of the adaptive Metropolis (AM) method with a mutation strategy for ensuring quick convergence and robust solutions. Its effectiveness was demonstrated in simulations on identifying the structural parameters with limited output data and noise polluted measurements.

• Journal of Microbiology
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• v.37 no.1
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• pp.1-9
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• 1999

The Biolog redox technology was carried out for evaluation of acidification effect on microbial communities at each stage of pH gradient microcosm. While the number of heterotrophic bacterial population and activities of extracellular enzyme decreased as the pH decreased, the number of total bacteria in the microcosm was not affected. The average color development of sample at each pH-gradient showed a sigmoidal curve, and at higher pH, more overall color development appeared in Biolog plates. Average color development value in Biolog plates was stabilized at 50 hours as an optimum incubation time. The color production in the Biolog plates was caused by cell density at above pH 5.0, but by cell activity below pH 4.0. Principal component analysis of color responses revealed distinctive patterns among the pH-gradient microcosm samples.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 1998.10a
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• pp.553-559
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• 1998

Simple Genetic Algorithm(SGA) proposed by J. H. Holland is a population-based optimization method based on the principle of the Darwinian natural selection. The theoretical foundations of GA are the Schema Theorem and the Building Block Hypothesis. Although GA goes well in many applications as an optimization method, still it does not guarantee the convergence to a global optimum in some problems. In designing intelligent systems, specially, since there is no deterministic solution, a heuristic trial-and error procedure is usually used to determine the systems' parameters. As an alternative scheme, therefore, there is a growing interest in a co-evolutionary system, where two populations constantly interact and co-evolve. In this paper we review the existing co-evolutionary algorithms and propose co-evolutionary schemes designing intelligent systems according to the relation between the system's components.

• Journal of Electrical Engineering and information Science
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• v.2 no.5
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• pp.51-59
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• 1997

This paper presets a methodology of improving a conventional model in power systems using Genetic Algorithms(GAs) and suggests a GAs-based model which can directly solve the real-valued optimum in an optimization procedure. In applying GAs to the power flow, a new fitness mapping method is proposed using the proposed using the probability distribution function for all the payoffs in the population pool. In this approach, both the notions on a way of the genetic representation, and a realization of the genetic operators are fully discussed to evaluate he GAs' effectiveness. The proposed method is applied to IEEE 5-bus, 14-bus and 25-bus systems and, the results of computational experiments suggest a direct applicability of GAs to more complicated power system problems even if they contain nonlinear algebraic equations.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.11a
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• pp.587-592
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• 2000

The optimization method based on an enhanced genetic algorithms is proposed for multimodal function optimization in this paper. This method is consisted of two main steps. The first step is global search step using the genetic algorithm(GA) and function assurance criterion(FAC). The belonging of an population to initial solution group is decided according to the FAC. The second step is to decide the similarity between individuals, and to research the optimum solutions by simplex method in reconstructive search space. Two numerical examples are also presented in this paper to comparing with conventional methods.

• Journal of the Korea Organic Resources Recycling Association
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• v.1 no.1
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• pp.69-84
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• 1993

In order to determine the optimum operational paramsters in cow manure composting, 4 laboratory scale composters were established. The cow manure was mixed with certain amount of saw dust to adjust the initial C/N ratio to 24, initial pH to 6.9 and composting was performed with varying operational conditions. It was found that the optimum aeration rate was 1000 ml/min kg. VS, the optimum moisture content 50% and no significant difference was found with different initial pH condition. Microorganisms were counted under the optimum conditions determined in this study. At the end of the experimental period, the number of bacteria, actinomycetes and fungi was $1.5{\times}10^9$ cells, $1.1{\times}10^8$ cells and $3.0{\times}10^8$ cells/g dry compost, respectively. At day 0, the number of coliforms, fecal coliforms and fecal streptococci was $3.1{\times}10^3$ cells, $7.5{\times}10^2$ cells and $5.6{\times}103$ cells/g dry composting material, respectively. Their population was decreased with time lapse, However, their survival time was longer than those reported by other researchers. Microorganisms were identified at the end of the experiment. Genus Bacillus was the most dominant comprising 89.3% of the total population. Among the Genus Bacillus, B. circulans compoex was the most abundant, followed by B. Stearothermophilus, B. Sphericus, B. licheniformis and B, brevis.

• Korean Journal of Environmental Biology
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• v.29 no.2
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• pp.81-91
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• 2011

To understand the spatio-temporal fluctuations and ecological characteristics of heterotrophic dinoflagellate $Noctiluca$ $scintillans$, we investigated their population densities and environmental factors during four seasons at 20 stations of Gwangyang Bay and at 23 stations of Jinhae Bay in 2010. $N.$ $scintillans$ was seasonally abundant during spring and summer, with temperature ranging 15 to $27^{\circ}C$ in the both bays, whereas the density reduced in fall and winter. The populations of $N.$ $scintillans$ at each station in both bays showed a significantly positive relationship with water temperature, indicating that relatively high water temperature within its optimum temperature stimulates the growth of $N.$ $scintillans$ population. In particular, low water temperature (<$4^{\circ}C$) and salinity (<12 psu) led to disappear of $N.$ $scintillans$ population, although they were observed at all season in both bays. Spatio-temporal variations of Chl.$a$ concentration was not significantly correlated with $N.$ $scintillans$ population densities. However, the $Noctiluca$ abundances were also high during spring and summer season when relatively high Chl.$a$ concentration was observed in both bays. This result suggests that standing crops of phytoplankton may be one of important contributing factors to enhance the abundance of $N.$ $scintillans$.