• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2009.10a
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• pp.285-289
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• 2009

In this paper, we propose to research the dynamic Matlab/Simulink model of supercapacitor bank(SCB) for a microgrid application. We demonstrated that this model id sufficient to design the control system of entire power storage system, SCB, the chopper and grid connected converter. The proposed dynamic model is simulated with the help of Matlab/$Simulink^{TK}$ in the MTG/PC/SCB hybrid energy system. The study results show that SCB have a good performance to curb power fluctuation in building microgrid application.

• International conference on construction engineering and project management
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• 2015.10a
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• pp.650-651
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• 2015

Value Engineering has been recognized as one of the construction management techniques for improving the value and benefits of whole project. However, due to the lack of the past data and inefficient free-thinking techniques, the idea generation during VE workshop is still inefficient and ineffective. Even though various studies related to theoretical methodology and technical systems relevant to database were conducted, VE team still mainly rely on their experience for idea generation. With this regard, this study suggests an approach of BIM-based idea bank and assesses its effectiveness by interviewing 20 VE experts in the industry. This approach covers the three steps of idea generation, consisting of 1) Developing BIM based VE database, 2) Generating VE ideas, 3) Updating VE ideas. The result showed that the proposed approach has great potentials to support VE team and improve the quality of VE ideas during creativity phase.

• Journal of Korea Water Resources Association
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• v.52 no.10
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• pp.743-752
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• 2019

The flow in the meandering channel is characterized by the spiral motion of secondary currents that typically cause the erosion along the outer bank. Hydraulic structures, such as spur dike and groyne, are commonly installed on the channel bottom near the outer bank to mitigate the strength of secondary currents. This study is to investigate the effects of submerged vanes installed in a $90^{\circ}$ meandering channel on the development of secondary currents through three-dimensional numerical modeling using the hybrid RANS/LES method for turbulence and the volume of fluid method, based on OpenFOAM open source toolbox, for capturing the free surface at the Froude number of 0.43. We employ the second-order-accurate finite volume methods in the space and time for the numerical modeling and compare numerical results with experimental measurements for evaluating the numerical predictions. Numerical results show that the present simulations well reproduce the experimental measurements, in terms of the time-averaged streamwise velocity and secondary velocity vector fields in the bend with submerged vanes. The computed flow fields reveal that the streamwise velocity near the bed along the outer bank at the end section of bend dramatically decrease by one third of mean velocity after the installation of vanes, which support that submerged vanes mitigate the strength of primary secondary flow and are helpful for the channel stability along the outer bank. The flow between the top of vanes and the free surface accelerates and the maximum velocity of free surface flow near the flow impingement along the outer bank increases about 20% due to the installation of submerged vanes. Numerical solutions show the formations of the horseshoe vortices at the front of vanes and the lee wakes behind the vanes, which are responsible for strong local scour around vanes. Additional study on the shapes and arrangement of vanes is required for mitigate the local scour.

• Journal of Soil and Groundwater Environment
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• v.13 no.2
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• pp.54-61
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• 2008

The drawdown distribution due to pumping by horizontal or slanted wells is analyzed by numerical modelling. In the numerical modelling uses 1-D discrete element feature included in commercial groundwater modeling program FEFLOW (version 5.1) and the results are compared with the semi analytic solution which uses superposition of successive point sources proposed by Zhan and Zlotnik (2002). Results of the numerical modeling agree well with the semi analytic solution except for very near field region of sink sources. The drawdown distribution due to pumping in riverbank filtration(RBF) plan site can be evaluated quantitatively by the numerical modeling in this study.

• Journal of Power Electronics
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• v.17 no.2
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• pp.442-452
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• 2017

This paper deals with the input-output modeling of a vector controlled PMSM drive system and design of a simple multiple model adaptive control (MMAC) scheme with desired transient responses. We present a discrete-time modeling technique using closed-loop identification that can experimentally identify the equivalent models in the d-q coordinates. A bank of linear models for the equivalent plant of the current loop is first obtained by identifying them at several operating points of the current to account for nonlinearity. Based on these models, we suggest a simple q-axis MMAC combined with a fixed d-axis controller. After the current controller is designed, another equivalent model including the current controller in the speed control loop shall be similarly obtained, and then a fixed speed controller is synthesized. The proposed approach is demonstrated by experiments. The experimental set up consists of a surface mounted PMSM (5 KW, 220V, 8 poles) equipped with a flywheel load of 220kg and a digital controller using DSP (TMS320F28335).

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.42 no.1
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• pp.38-43
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• 2006

The 3-D modeling of ocean finite element method(OFEM) using $k-{\varepsilon}$ turbulent model and tetrahedron grids has been used to investigate the internal wave generation during the expansion of the deep water from the open sea to the shelf with a simple shape, which can be widely used in the fields of submarine development, ocean environment and meteorology, etc. In this paper, the detailed configuration of internal wave with its length and height and also the distribution of salinity and turbulent kinematic energy, etc. were derived. It is hoped that this OFEM method can be successfully applied to the numerical calculation of internal wave for and the oceanographic problems (tidal flows around underwater hill, plateau, Georges Bank, etc.) and ocean engineering problems(flow past artificial sea reefs) in future.

• Corrosion Science and Technology
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• v.11 no.4
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• pp.103-107
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• 2012

In the framework of an International cooperation program in Australia-Asia, the atmospheric corrosion of metals in five nations located in this tropical zone: Australia, Vietnam, Thailand, Philippines and Indonesia was investigated. In this program, mild steel, zinc and copper were tested on a set of sites, representative for different climatic conditions: severe marine, marine, industrial, urban and rural, simultaneously with the collection of climatic parameters and pollutants. Based on the data obtained in the Program and referring to the bank of data collected in the Vietnam National Projects, modeling was used to construct a corrosion map of steel for Vietnam. The correlation of the data derived from the map compared with those from National Projects is very high, in most cases, differing by less than 2-3%.

• Bulletin of the Korean Chemical Society
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• v.23 no.7
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• pp.1003-1010
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• 2002

Caspase 3, a member of cysteine protease family, is well known as a major apoptosis effector and is involved in cell death as a result of ischemic diseases such as stroke and myocardial infarction, therefore the inhibition of caspase 3 may protect those apoptotic cell damages. During the high-throughput screening of the compounds from the Korea Chemical Bank, berberine derivatives (A and B), an isoquinoline alkaloid, have been identified as potential inhibitors for caspase 3. Based on this finding we carried out molecular modeling study to identify the pharmacophoric elements of berberine structure which interact with a substrate-recognition binding site of caspase 3 and came up with several novel scaffolds. In this report, we will discuss the molecular modeling, syntheses and the enzyme inhibitory activities of these novel compounds.

• Journal of Institute of Control, Robotics and Systems
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• v.8 no.11
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• pp.928-934
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• 2002

A natural way to cope with fault tolerant control (FTC) problems is to modify the control parameters according to an online identification of the system parameters when a fault occurs. However. due to not only difficulties Inherent to the online multivariable identification in closed-loop systems, such as modeling errors, noise or the lack of excitation signals, but also long time requirement to identify the post-fault system and implemeutation of control problems during the identification process, we propose an alternative approach based on the observer-based fault detection and isolation (FDI) and model reference adaptive control (MRAC). The proposed robust fault diagnosis method is based on a bank of observers. We also propose a model reference adaptive control with changeable reference models according to the occurred faults. Simulation results of a flight control example show the validity and applicability of the proposed algorithms.

• The Transactions of the Korea Information Processing Society
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• v.7 no.9
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• pp.2846-2856
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• 2000

Recently, according to the rapid development of web technology, a lot of applications based on web techniques have been developed. However, most of web applications have been developed relying on knowledge and experiences of the developer without systematic process. Web Applications are seldom developed in isolation. For web application designers, the simple and semantically rich methodology is needed to improve design and development process. In this paper, we propose a new development process methodology to improve low level technology based application development process which do not provide high level abstraction. We also suggest a new methodology to construct applications based on web. We describe a systematic web application development process by using Navigation Diagram as a analysis, design modeling method to develop web application with productivity and Quality. We apply the new development process to the EPBS(Electronic Problem Bank System) as examples. Web application development process proposed in this thesis can be maintained through reverse development, because it can be defined as high level abstraction for modeling. It is very easy to be understood as a process based on models. Also, analysis and design models can be reused as useful component whenever similar web application is developed.