• Journal of Korea Water Resources Association
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• v.55 no.10
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• pp.707-721
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• 2022

In this study, a state-of-the-art review on urban inundation simulation technology was presented summarizing major achievements and limitations, and future research recommendations and challenges. More than 160 papers published in major domestic academic journals since the 2000s were analyzed. After analyzing the core themes and contents of the papers, the status of technological development was reviewed according to simulation methodologies such as physically-based and data-driven approaches. In addition, research trends for application purposes and advances in overseas and related fields were analyzed. Since more than 60% of urban inundation research used Storm Water Management Model (SWMM), developing new modeling techniques for detailed physical processes of dual drainage was encouraged. Data-based approaches have become a new status quo in urban inundation modeling. However, given that hydrological extreme data is rare, balanced research development of data and physically-based approaches was recommended. Urban inundation analysis technology, actively combined with new technologies in other fields such as artificial intelligence, IoT, and metaverse, would require continuous support from society and holistic approaches to solve challenges from climate risk and reduce disaster damage.

• Smart Media Journal
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• v.13 no.10
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• pp.67-78
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• 2024

In the era of the Fourth Industrial Revolution, modern society is evolving beyond an information society into a hyperconnected society, with the advancement of technology leading to the development of smart cities. According to Cohen (2015), the direction of smart city evolution is shifting from a technology-driven approach to a citizen co-creation model, and living labs play a crucial role in this transition. The objective of this study is to empirically analyze the success factors of living labs in smart cities using the citizen co-creation approach, focusing on social capital. Social capital is measured by variables such as interest, networks, trust, and norms, while the success factors of living labs are analyzed through variables like communication, democracy (conflict acceptance), and open innovation. The analysis results showed that, among the success factors of living labs, communication was positively influenced by trust, norms, and networks, with trust having the greatest impact. Democracy (conflict acceptance) was positively influenced by norms and interest, while open innovation was positively influenced by norms and interest as well. This study concludes that the formation of social capital is crucial for the success of living labs in smart cities following the citizen co-creation model. In particular, the formation of trust among neighbors, colleagues, national and local governments is vital. Additionally, adherence to laws, regulations, and community agreements, as well as interest in various local events and policies, are essential. Based on these findings, this study suggests that while smart cities may have originated from technology, they must ultimately be pursued based on people-centered participation, interest, and trust for sustainable development.

• The Transactions of the Korea Information Processing Society
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• v.2 no.4
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• pp.567-580
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• 1995

A transition-based Objet-oriented programming system(TOPS) is a transition-based object-oriented system suitable for development of various concurrent systems.A TOPS consists of a collection of interacting structural active objects(SAOs),and their behaviors are determined by the transition statements provided in their class definitions.Furthermore,SAOs can be structurally and hierarchcally composed from their component SAOs like hardware commponents. These features allow SAOs to model components for circuit simulation more naturally than passive objects used in ordinary object-oriented programming. Also,we can easily add new kinds of components by using the inheritance mechanism.Executions of transition statements may be eventand/or time-driven, and hence digital,and mixed-mode simulation is possible.Prototype simulation programs with graphical user interfaces have been developed as TOPS progrms for digital,analog,and mixed-mode circuit simulation.

• International Journal of Naval Architecture and Ocean Engineering
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• v.6 no.2
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• pp.219-235
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• 2014

With the development of the technology of underwater moving bodies, the need for developing the knowledge of surface effect interaction of free surface and underwater moving bodies is increased. Hence, the two-phase flow is a subject which is interesting for many researchers all around the world. In this paper, the non-linear free surface deformations which occur during the water-exit of a circular cylinder due to its buoyancy are solved using finite volume discretization based code, and using Volume of Fluid (VOF) scheme for solving two phase flow. Dynamic mesh model is used to simulate dynamic motion of the cylinder. In addition, the effect of cylinder mass in presence of an external force is studied. Moreover, the oblique exit and entry of a circular cylinder with two exit angles is simulated. At last, water-exit of a circular cylinder in six degrees of freedom is simulated in 3D using parallel processing. The simulation errors of present work (using VOF method) for maximum velocity and height of a circular cylinder are less than the corresponding errors of level set method reported by previous researchers. Oblique exit shows interesting results; formation of waves caused by exit of the cylinder, wave motion in horizontal direction and the air trapped between the waves are observable. In 3D simulation the visualization of water motion on the top surface of the cylinder and the free surface breaking on the front and back faces of the 3D cylinder at the exit phase are observed which cannot be seen in 2D simulation. Comparing the results, 3D simulation shows better agreement with experimental data, specially in the maximum height position of the cylinder.

• Journal of Korean Society for Atmospheric Environment
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• v.31 no.5
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• pp.411-429
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• 2015

The Korea Ministry of Environment has established an air quality standard for $PM_{2.5}$ in 2012 and it is effective from January 2015. In this study, we review various aspects of $PM_{2.5}$ in China, including its measurement, modeling, source apportionment, and health effect, and suggest future research directions for $PM_{2.5}$ studies in Korea. Measurements studies for $PM_{2.5}$ have examined organic marker compounds and $^{14}C$ as well as inorganic aerosols for distinguishing sources. Modeling results supported that the control of $PM_{2.5}$ pollution in big city needs effective cooperation between city and its surrounding regions. The major $PM_{2.5}$ sources in China have been identified to be secondary sulfur, motor vehicle emissions, coal combustion, dust, biomass burning, and industrial sources, however, they have seasonal dependency. Especially, the severe haze pollution event during January 2013 over eastern and northern China was driven to a large extent by secondary aerosol formation. Short-term exposure to $PM_{2.5}$ is strongly associated with the increased risk of morbidity and mortality from cardiovascular and respiratory diseases, as well as total non-accidental mortality. Considered previous $PM_{2.5}$ studies in China, analysis of specific organic species using online measurement, chamber experiment for secondary aerosol formation mechanism, and development of parameterizing this process in the model are needed to elucidate factors governing the abundance and composition of $PM_{2.5}$ in Korea.

• Journal of Broadcast Engineering
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• v.25 no.2
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• pp.176-184
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• 2020

Due to constant development and decline on Seoul areas the Seoul government is pushing various policies to regenerate declined Seoul areas. Theses various policies lead to land-use changes around numerous Seoul districts. This study aims to create prediction model which can foresee future land-use changes and while doing so, tried to derive various influential factors which leads to land-use changes. To do so, various open-data from national departments and Seoul government have been collected and implemented into random forest algorithm. The results showed promising accuracy and derived multiple influential factors which causes land-use changes around Seoul districts. The result of this study could further be implemented in policy makings for the public sectors, or could also be used as basis for studying gentrification problems happening in Seoul Area.

• Korea-Australia Rheology Journal
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• v.19 no.4
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• pp.233-242
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• 2007

We performed a numerical investigation to find out the optimal choice of the spatial discretization in the distributed-Lagrangian-multiplier/fictitious-domain (DLM/FD) method for the solid/fluid interaction problem. The elastic solid bar attached on the bottom in a pressure-driven channel flow of a Newtonian fluid was selected as a model problem. Our formulation is based on the scheme of Yu (2005) for the interaction between flexible bodies and fluid. A fixed regular rectangular discretization was applied for the description of solid and fluid domain by using the fictitious domain concept. The hydrodynamic interaction between solid and fluid was treated implicitly by the distributed Lagrangian multiplier method. Considering a simplified problem of the Stokes flow and the linearized elasticity, two numerical factors were investigated to clarify their effects and to find the optimum condition: the distribution of Lagrangian multipliers and the solid/fluid interfacial condition. The robustness of this method was verified through the mesh convergence and a pseudo-time step test. We found that the fluid stress in a fictitious solid domain can be neglected and that the Lagrangian multipliers are better to be applied on the entire solid domain. These results will be used to extend our study to systems of elastic particle in the Stokes flow, and of particles in the viscoelastic fluid.

• Journal of Ocean Engineering and Technology
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• v.25 no.6
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• pp.1-8
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• 2011

This paper describes a new method for a digital gas metal arc welding (GMAW) system. The GMAW system is an arc welding process that incorporates the GMAW power source (PS-GMAW) with a wire feed unit (WFU). The PS-GMAW requires an electric power of constant voltage. A constant magnitude is maintained for the arc current by controlling the wire-feed speed of the WFU. A mathematical model is derived, and a self-tuning fuzzy proportional-integral-derivative (PID) controller is designed and applied to control the welding current. The electrode wire feeding mechanism with this controller is driven by a DC motor, which can compensate for both the molten part of the electrode and undesirable fluctuations in the arc length during the welding process. By accurately maintaining the output welding current and welding voltage at constant values during the welding process, excellent welding results can be obtained. Simulation and experimental results are shown to prove the effectiveness of the proposed controller.

• Journal of the Korean Society for information Management
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• v.27 no.1
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• pp.137-163
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• 2010

Library course pages are an integrated service providing both course management information and library resources as one gateway to strengthen university libraries' information services. It is possible to associate course management system and library resources, and to provide course-specific information rather than library interface with various searching gateways. In the case of foreign university libraries, library course pages have been developed more effectively and variously for university's environment and characteristics, and have been built for all the courses in a university by system processing, not manually. In foreign libraries, there are many sophisticated, dynamic, database-driven house-developed and vendor-developed systems for library course pages than hand coded HTML pages. But in Korea, there is a lack of awareness of the importance of library course pages among librarians, and the programs of library course pages have not yet been developed. Therefore, this study is to build the model for library course pages using literature reviews and case studies. Then, this study could also lay the foundation for effective library services and the system development of library course pages.

• Journal of Arbitration Studies
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• v.11 no.1
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• pp.37-73
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• 2001

I. Preface It is widely understood that the 21st century, with the development of information technology(IT) and the spread of networks, will be called a digital economy where information-driven business will be norm rather than the smokestack economy of the past. And the drastically changed world market is expected to generate even more commercial transactions across the world creating large numbers of legal disputes. Therefore, each country will attempt to develop ADR(Alternative Dispute Resolution) as an alternative to judicial proceedings in order to cope with not only the ever-increasing international commercial claims but also domestic legal disputes. Taking this reality into account, this study begins with an exploration of mediation procedure as a way of helping the court faced with its overwhelming numbers of lawsuits. And also this study makes a theoretical comparison between ADR and mediation procedure, analyzing critical factors affecting the mediation agreement. Furthermore, it is designed to find ways for disputing parties to make better use of mediation and ensure fairness to the parties involved. It tries to enhance mediators' understanding of critical factors influencing the mediation agreement and their ability to handle commercial disputes in a more efficient way. To make an empirical analysis of these factors, bibliographic research and questionnaire were used. This analysis will fill the gap between the theory and reality, and make possible the structured research on the factors. Therefore, this study sets the model by which we can evaluate how the three critical factors (parties' inclination, mediators' characteristics, institutional features) affect the parties reaching a mediation agreement. Based on this analysis, a theoretical hypothesis was built and a questionnaire was made and distributed. During the course of this work, SPSSWIN 10.0 program was applied.