• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.7
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• pp.1391-1397
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• 1992

Improved power law flow model was suggested for the calculation of wake flow characteristics around the three dimensional ship stern in case of the formation of bilge vortex in the direction of stern. In comparison with the power law and Coles flow model, the flow velocity calculated based on this study was delayed around the boundary of inner layer and outer layer in reverse flow. More accurate results was obtained with this improved power law flow model by the velocity calculation around ship stern. Accuracy was validated with the comparison of other calculation results and experimental datas.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.7
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• pp.930-939
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• 2004

Constitutive models for final stage densification of metal powder compacts with power-law creep deformation were investigated. The constitutive models were implemented into a finite element program (ABAQUS) by using user subroutine CREEP and, from FEM results, useful densification curves were obtained when hydrostatic and uniaxial stress were applied to the powder compacts at various pressures and temperatures. Because the densification behavior varied as the constitutive models, the equivalent stress surface on each constitutive equation was investigated to analyze the difference of densification behavior.

• Journal of the Korean GEO-environmental Society
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• v.1 no.1
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• pp.35-42
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• 2000

The settlement characteristics of waste landfill site must be considered in the design of sanitary landfill as well as in the course of the rehabilitation of the landfill site. Among prediction methods for settlement of landfill site, especially Gibson and Lo model and Power Creep Law have been successfully applied to the landfill site where the amount of settlement was large and the secondary settlement was obvious. Therefore, the effects of organic content on the model parameter values utilized in both Gibson Lo model and Power Creep Law were studied by using a large consolidation testing apparatus. The organic content is each 20%, 40%, 60% of total volume and consolidation load is $0.1{\sim}1.6kg/cm^2$. The main results can be summarized as follows: (1) The reference compressibility of Power Creep Law is decreased according to the increments of consolidation load: (2) The field measurement is more similar to the Power Creep Law than the Gibson and Lo model.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.10B
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• pp.938-946
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• 2003

Studies of Internet algorithms or policies require experiments on the real large-scale networks. But practical problems with large real networks make them difficult. Instead many researchers use simulations on the Internet topology models. Some tried to find out abstract topological properties of Internet. And several models are proposed to reflect Internet's topological characteristics better. But few studies have been performed on how to model the evolution of Internet. We propose algorithms for modeling addition and removal of nodes and accompanied change of topologies. We analyze the topologies generated by our algorithms to observe that they obey the power-laws better than those generated by existing ones. These algorithms are also expected to be helpful in predicting future topologies of Internet.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.04a
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• pp.337-340
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• 2011

This study investigates the rheological characteristics of $SiO_2$-Kerosene gel propellants with Aerosil(R) R972, Silica 230, Silica 530. Power-law rheological model is used to confirm whether or not gelification is achieved. It was found that the produced gel have shear-thinning effect, and that the viscosity of the gel propellants increases with increasing $SiO_2$ concentration. Among gellants used in this study, gel propellant with Aerosil(R) R972 fits most to the power law model as the shear rate increases. However, gels produced with Silica 230 and Silica 530 gellant deviate from the power law model when the shear rate regime is below 100 [1/s].

• Clean Technology
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• v.19 no.1
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• pp.51-58
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• 2013

In this study, kinetics data was obtained for steam reforming reaction of ethane over the nickel catalyst. The variables of steam reforming reaction were reaction temperature, partial pressure of ethane, and mole ratio of steam and ethane. Parameters for the power rate law kinetic model and the Langmuir-Hinshelwood model were obtained from the kinetic data. Also, sizing of steam reforming reactor was performed by using PRO/II simulator. For the steam reforming reaction of ethane, Langmuir-Hinshelwood model determining the reaction rate by the surface reaction was better suited than a simple power rate law kinetic model. On water-gas-shift reaction, power rate law kinetic model was well fitted to the kinetic data. Reactor size can be calculated for production of hydrogen through PRO/II simulation.

• Journal of the Korean Society of Propulsion Engineers
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• v.16 no.6
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• pp.23-31
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• 2012

Present work deals three families of $SiO_2$ gelling agents which have been used to produce gel fuel based on Kerosene. Jet A-1 is chosen as fuel where power-law rheological model is used to confirm whether or not the gelification is achieved depending on the %wt of gellant. It was confirmed that the produced jelly-like substance have shear-thinning effect, and that its apparent viscosity increases as $SiO_2$ concentration increases. Compared to other gellants, gel with Aerosil(R) R972 fits most to the power-law model, while gels with Silica 230 and Silica 530 deviate from the power-law model. The rheological characteristics behaved differently depending on the mixing method(vortex mixing and manual mixing) when gellant concentration is increased.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.7
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• pp.914-924
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• 2020

In this study we developed artificial network generation model, which can generate on-line social network. The suggested model can represent not only scale-free and small-world properties, but also can produce networks with various values of topological characteristics through controlling two input parameters. For this purpose, two parameter K and P are introduced, K for controlling the strength of preferential attachment and P for controlling clustering coefficient. It is found out on-line social network can be generated with the combinations of K(0~10) and P(0.3~0.5) or K=0 and P=0.9. Under these combinations of P and K small-world and scale-free properties are well represented. Node degree distribution follows power-law. Clustering coefficients are between 0.130 and 0.238, and average shortest path distance between 5.641 and 5.985. It is also found that on-line social network properties are maintained as network node size increases from 5,000 to 10,000.

• Proceedings of the Safety Management and Science Conference
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• 2007.04a
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• pp.335-346
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• 2007

This paper introduces reliability stress screening(RSS) for electronic hardware and components. This study also shows reliability centered maintenance(RCM), and reliability growth models. Moreover, this paper presents goodness-of-fit tests and estimation methods of power law model.

• Journal of the Korean Geosynthetics Society
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• v.10 no.4
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• pp.105-112
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• 2011

This paper presents the numerical modelling technique for modeling the time-dependent behavior of geosynthetic reinforced soil wall under a sustained load. The applicability of power law-based creep models for modeling the creep deformations of geogrid and reinforced soil was first examined. The modeling approach was then used to simulate the long-term performance of a geosynthetic reinforced soil wall used in a bridge abutment. The results indicated that the power law-based models can be effectively used for modelling the long term behavior of geosynthetic reinforced walls under sustained loading. In addition, it was shown that, when using creep deformation susceptible backfill soils, the abutment wall and the sill beam may experience deformations exceeding allowable limits. Practical implications of the findings from this study are discussed in great detail.