• Transactions of the Korean Society of Automotive Engineers
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• v.4 no.4
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• pp.179-189
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• 1996

An unstructured grid finite-volume method has been applied to predict the linear and nonlinear attenuation characteristics of the expansion chamber silencer system. In order to achieve a grid flexibility and a solution adaptation for geometrically silencer system. In order to achieve a grid flexibility and a solution adaptation for geometrically complex flow regions associated with the actual silencers, the unstructured mesh algorithm in context with the node-centered finite volume method has been employed. The present numerical model has been validated by comparison with the analytical solutions and the experimental data for the acoustic field of the concentric expansion chamber with and without pulsating flows, as well as the axisymmetric blast flowfield with open end. Effects of the chamber geometry on the nonlinear wave attenuation characteristics is discussed in detail.

• Journal of Electrical Engineering and Technology
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• v.12 no.5
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• pp.1709-1718
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• 2017

This paper presents a hybrid stochastic deterministic multi-timescale scheduling (SDMS) approach for generation scheduling of a power grid. SDMS considers flexible resource options including conventional generation flexibility in a chance-constrained day-ahead scheduling optimization (DASO). The prime objective of the DASO is the minimization of the daily production cost in power systems with high penetration scenarios of variable generation. Furthermore, energy storage is scheduled in an hourly-ahead deterministic real-time scheduling optimization (RTSO). DASO simulation results are used as the base starting-point values in the hour-ahead online rolling RTSO with a 15-minute time interval. RTSO considers energy storage as another source of grid flexibility, to balance out the deviation between predicted and actual net load demand values. Numerical simulations, on the IEEE RTS test system with high wind penetration levels, indicate the effectiveness of the proposed SDMS framework for managing the grid flexibility to meet the net load demand, in both day-ahead and real-time timescales. Results also highlight the adequacy of the framework to adjust the scheduling, in real-time, to cope with large prediction errors of wind forecasting.

• Korean Institute of Interior Design Journal
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• no.17
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• pp.181-186
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• 1998

Grid serves as an auxiliary instrument that explains design logically and objectively when you designing an interior. But grid is unacceptable to the space which is produced by designer who wants to express a design subjectively. Because grid makes usual and standardized space without flexibility. Changing and developing a fundamental unit with modern touch is going to be a way compensate for the weakpoint Also versatile grid unit can support the designer's subjective intention. This study focuses on the limits of Wright's house which show interior space aestheically through grid planing. In this paper Wright's uniqe interior space pattern will be examined through the selection of some of his works specifically the Prairies and Usonians whose transforming is noticable as Wright house and analysis about formation process of grid planning characteristics and spaces is continued. With all this analysis I'm, going to look over Wright's philosophy and pattern that is usually intended by his grid planning.

• 한국정보디스플레이학회:학술대회논문집
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• 2002.08a
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• pp.376-378
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• 2002

Within LG.Philips Displays electron gun assembly different grid alignment methods are used. Besides the commonly used mandrel alignment of grids (Inner Reference System, IRS), also a unique Outer Reference System (ORS) is used as grid alignment method in high-end gun assembly. This alignment method combines alignment accuracy with maximum electron optical design freedom and maximum flexibility in electron gun production.

• Journal of computational fluids engineering
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• v.2 no.1
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• pp.84-92
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• 1997

In this paper a new structured grid generation technique is introduced. This new technique utilizes predictor-corrector approach, and is a marching scheme in the global sense as the hyperbolic scheme is. In the predictor step, one layer of grid cells is obtained by using Modified Advancing Front Method which generates a collection of quadrilateral cells simultaneously. In the corrector step, the layer of grid cells that is calculated in the predictor step is adjusted by solving Laplace equations to prevent grid lines from skewing and overlapping in highly curved configurations. It is shown that the resultant algorithm, named a MAP scheme, which combines the Modified Advancing Front Method as a Predictor with an elliptic scheme as a corrector can be used to generate globally smooth and locally near-orthogonal grids for external flow fields even for highly curved configurations. Examples of grid generations for external flow fields about several configurations by use of the present approach are given, and its applicability and flexibility have been demonstrated and discussed.

• Journal of Mechanical Science and Technology
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• v.19 no.4
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• pp.1006-1017
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• 2005

In this work, we developed an accurate and efficient radiative finite volume method applicable for the complex 2D planar and 3D geometries using an unstructured-grid finite volume method. The present numerical model has fully been validated by several benchmark cases including the radiative heat transfer in quadrilateral enclosure with isothermal medium, tetrahedral enclosure, a three-dimensional idealized furnace, as well as convection-coupled radiative heat transfer in a square enclosure. The numerical results for all cases are well agreed with the previous results. Special emphasis is given to the parallelization of the unstructured-grid radiative FVM using the domain decomposition approach. Numerical results indicate that the present parallel unstruc­tured-grid FVM has the good performance in terms of accuracy, geometric flexibility, and computational efficiency.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.441-441
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• 2014

The characteristics of hybrid conductive films based on multilayer graphene and silver grid have been investigated for the high-performance and flexible organic solar cells. The hybrid conductive films have been prepared on glass and polyethylene terephthalate (PET) substrates using conventional photolithography process and transfer process of graphene. The optical and electrical properties of prepared conductive films show transmittance of 87% at 550nm and sheet resistance of $28{\Omega}/square$. The electromechanical properties were also investigated in detail to confirm the flexibility of the hybrid films. OSCs have been fabricated on the hybrid conductive films based on graphene and silver grid on glass substrate. The power conversion efficiency of 2.38%, a fill factor of 51%, an open circuit voltage of 0.58V and a short circuit current of $8.05mA/cm^2$ were obtained from the device on glass substrate. The PCE was enhanced 11% compared with OSCs on the MLG films without silver grid.

• The Journal of the Korea institute of electronic communication sciences
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• v.19 no.1
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• pp.93-104
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• 2024

Demand response is a strategy that encourages customers to adjust their consumption patterns at times of peak demand with the aim to improve the reliability of the power grid and minimize expenses. The integration of renewable energy sources into smart grids poses significant challenges due to their intermittent and unpredictable nature. Demand response strategies, coupled with reinforcement learning techniques, have emerged as promising approaches to address these challenges and optimize grid operations where traditional methods fail to meet such kind of complex requirements. This research focuses on investigating the application of reinforcement learning algorithms in demand response for renewable energy integration. The objectives include optimizing demand-side flexibility, improving renewable energy utilization, and enhancing grid stability. The results emphasize the effectiveness of demand response strategies based on reinforcement learning in enhancing grid flexibility and facilitating the integration of renewable energy.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.10
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• pp.17-25
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• 2005

A grid adaptation method within systems of chimera and patched grids is presented. Problem domains are divided into near-body and off-body fields. Near-body field is filled with curvilinear body-fitted grids that extend only a short distance from body surfaces and connected to other grid systems via chimera domain connectivity method. Off-body field is filled with patched uniform cartesian grids of varying levels of refinement. This method gives flexibility in grid generation and efficient adaptation capability. Several numerical experiments including 2D store separation were performed to show the performance of the proposed adaptation method.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.14 no.1
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• pp.91-97
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• 2021

ISO/IEC 15118 is an international communication standard for EV(electric vehicle)'s V2G implementation. In the charging/discharging control of an EV based on a communication protocol, there is inevitably a time delay when charging/discharging occurs, and the delay may limit in supplying power flexibility. In this paper, we implemented an ISO/IEC 15118-based V2G emulator and measured the charge/discharge response characteristics. As a result, the time delay appeared as 0.12ms. Accordingly, the power flexibility markets that EV can participate in under the current standard were explored.