• Journal of Korean Society for Atmospheric Environment
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• v.15 no.E
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• pp.55-64
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• 1999

The CIT(California Institute of Technology) three-dimensional Eulerian photochemical model was applied to the Greater Seoul Area, Korea for July 24, 1994, a day of the 9-day ozone episode to understand the characteristics of photochemical air pollution problems in the area. The modeling domain was 60km$\times$60km with the girl size of 2km$\times$2km. As the base case emissions, air pollutant emission data of the National Institute of Environmental Research, Korea for the year of 1991 were used with modifications based on EKMA(Empirical Kinetic Modeling Approach) resutls. Comparisons between predicted and observed concentrations showed that the model predicted the peak concentration over the domain reasonably. It was found that the location of the peak ozone concentration was mainly decided by metorological conditions. But the model could not resolve the spatial variations of concentration station by station, which was mainly caused by localized variations in emission and meteorology.

• Journal of the Korean Solar Energy Society
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• v.39 no.4
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• pp.55-67
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• 2019

Recently, as the amount of particulate matter blowing from China increases, the domestic air environment is rapidly deteriorating. This pollution of the atmosphere greatly affects the light energy reaching the ground. Particularly, since the light enters the solar cell module in various forms, the amount of input energy of the solar power generation system may be changed depending on the ratio of direct beam irradiation and diffused horizontal irradiation. In this paper, we analyze how the ratio of direct beam component and diffused component on global horizontal irradiation varies with the atmospheric conditions. In addition, the reliability of the regression equation, designed to decompose the global horizontal irradiation into horizontal direct beam irradiation and diffused horizontal irradiation, was verified according to the level of air pollution. So, we derive the most suitable decomposition model for use in domestic climatic conditions in Korea by comparing the ratio of direct and diffuse component on the horizontal which is calculated with Perez model and Watanabe model using the meteorological weather data observed for 14 months. Finally, to reduce the error of the transposition result, we verified the reliability of the decomposition which depends on the atmospheric environment.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.2
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• pp.536-564
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• 2019

Soft faults are inherent in wireless sensor networks (WSNs) due to external and internal errors. The failure of processes in a protocol stack are caused by errors on various layers. In this work, impact of errors and channel misbehavior on process execution is investigated to provide an error classification mechanism. Considering implementation of WSN protocol stack, inter-process correlations of stacked and peer layer processes are modeled. The proposed model is realized through local and global decision trees for fault diagnosis. A hybrid framework is proposed to implement local decision tree on sensor nodes and global decision tree on diagnostic cluster head. Local decision tree is employed to diagnose critical failures due to errors in stacked processes at node level. Global decision tree, diagnoses critical failures due to errors in peer layer processes at network level. The proposed model has been analyzed using fault tree analysis. The framework implementation has been done in Castalia. Simulation results validate the inter-process correlation model-based fault diagnosis. The hybrid framework distributes processing load on sensor nodes and diagnostic cluster head in a decentralized way, reducing communication overhead.

• Steel and Composite Structures
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• v.50 no.5
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• pp.549-562
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• 2024

In this study a steel moment frame system to be installed on the exterior surface of an existing structure is proposed as a seismic retrofit device. The seismic performance of the retrofit system was investigated by installing it on the exterior of a single story single bay reinforced concrete frame and testing it under cyclic loading. The cyclic loading test results indicated that the steel frame significantly enhanced the strength and ductility of the bare structure. Finite element analysis was carried out to validate the test results, and it was observed that there was good agreement between the two results. An analytical model was developed in order to apply the retrofit system to an example structure subjected to seven mainshock-aftershock sequential earthquake records. It was observed that the model structure was severely damaged due to the mainshock earthquakes, and the seismic response of the model structure increased significantly due to the subsequent aftershock earthquakes. The seismic retrofit of the model structure using the proposed steel frame turned out to be effective in decreasing the seismic response below the given limit state.

• Journal of the Chungcheong Mathematical Society
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• v.28 no.1
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• pp.161-172
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• 2015

In this paper, we consider the chemotaxis-haptotaxis model of tumor invasion with the proliferation and tissue re-establishment term in dimensions one and two. We show the global in time existence of a unique classical solution for the the model in two dimensional spatial domain without any restrictions on the coefficients.

• Bulletin of the Korean Mathematical Society
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• v.54 no.2
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• pp.383-389
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• 2017

This paper devotes to the study of a diffusive model for unstirred membrane reactors with maintenance energy subject to a homogeneous Neumann boundary condition. It shows that the unique constant steady state is globally asymptotically stable when it exists. This result further implies the non-existence of the non-uniform steady state solution.

• Journal of applied mathematics & informatics
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• v.19 no.1_2
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• pp.165-177
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• 2005

In this paper, an adaptive trust region method based on the conic model for unconstrained optimization problems is proposed and analyzed. We establish the global and super linear convergence results of the method. Numerical tests are reported that confirm the efficiency of the new method.

• Journal of applied mathematics & informatics
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• v.29 no.1_2
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• pp.75-85
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• 2011

In this paper, using the energy estimates and the bootstrap arguments, the global existence of classical solutions for a prey-predator model with non-monotonic functional response and cross-diffusion where the prey and predator both have linear density restriction is proved when the space dimension n < 10.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2000.05a
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• pp.122-125
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• 2000

The paper describes the adaptation of evolutionary fuzzy model ins (EFM) in developing global function approximation tools for use in genetic algorithm based optimization of nonlinear structural systems. EFM is an optimization process to determine the fuzzy membership parameters for constructing global approximation model in a case where the training data are not sufficiently provided or uncertain information is included in design process. The paper presents the performance of EFM in terms of numbers of fuzzy rules and training data, and then explores the EFM based sizing of automotive component for passenger protection.

• Journal of Digital Convergence
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• v.10 no.1
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• pp.215-228
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• 2012

This study aims to answer the research question of what are the global leadership competencies(GLC) and what is the integrating framework of GLC? To attain the goal of reframing the GLC models with systematic research on GLC, the specific objectives are delineated as follows; the first objective is to identify the area of GLC. The second one is to extract the dimensions agreed with consensus. The third one is to suggest the reframed GLC model. Through the literature review and content analysis about GLC and global mindset, the two dimensions-subject and objects-of GLC model are emerged to classify the existing clusters of GLC. The extracted objects are self, others, culture, business, and global world. The dimension of subject who is global leader is more specifically divided into the knowing/doing process and three aspects of human activity like cognitive, emotional, and behavioral one. GLC are reframed and rearranged based on the two dimensions. As a results new framework for GLC with 11 clusters are presented. Knowing group of GLC contains personal, social, cultural, business literacy, and global mindset. Doing group of GLC contains personal, social, cultural, business savvy, and global change. Personal traits as a core character are at the core of the knowing and doing process of the self. Lastly, the implications and limitations of this research are suggested, and suggestion for further research is followed.