• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.2
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• pp.620-626
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• 2016

Estimating the nonlinear seismic response of structure in earthquake engineering is important. Nonlinear static analysis is a typical method, and a variety of methods and techniques for estimating the stiffness of structural system at a certain analysis stage have been introduced and used in numerical structural analysis. On the other hand, such methods have many difficulties in practical usage because they use time-consuming iterative methods or simplified algorithms for calculating the structural stiffness at specific points in the time of nonlinear static analysis. For this reason, this study suggests an accurate and effective method for estimating the stiffness of a structure in nonlinear static analysis. For this goal, existing theories of an incremental step-by-step solution was investigated first. Subsequently, an algorithm available for calculating the precise stiffness of a structural system, each element of which has a bilinear material model, was developed based on the investigated methods. Finally, a computer program, sNs, was developed with the algorithm used.

• Journal of Korea Society of Digital Industry and Information Management
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• v.14 no.4
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• pp.189-204
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• 2018

The purpose of this study is to examine an organizational performance difference by individual utilization level of the smart work. The Smart work help minimizing business process and improving organization productivity based on information technology. This new technology provides a flexible way of the task through smart-work center, videoconferencing, telecommuting, mobile(remote control) and business-only messenger. This investment changes organizational culture, institutions and behavior by new technology applying. The organization system change due to smart work has trouble between alteration preferences and existing maintains a group. In response, the organization should make investment justification of smart work for institutional and culture stabilized by a new system in organization. I set up the analytical process of four stages for empirical research. It will analyze an operation difference of the smart work between pre and post investment in the first-step analysis. The two-step analysis will conduct a text mining analysis of smart work operations. The three-step analysis will identify organization performance differences among individual levels in smart work. The four-step analysis will identify a factor difference in organizational performance by individual utilization level on smart work. According to the study, It has been revealed a difference between the pre and post investment performance on smart work. The text mining analyses many appeared an improvement opinion of organizational culture. Next, there is a difference in organization performance among utilize groups of smart work. Furthermore, the factors of organizational performance among groups appeared differently. The theoretical contribution of this study provided to expand the organizational theory of organization change and resistance. The practical implications provided to require a strong guideline an organizational culture and institution for smart work.

• Journal of the Architectural Institute of Korea Planning & Design
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• v.35 no.7
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• pp.45-52
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• 2019

In recent years, there has been a demand for a residential supply model that can actively and flexibly cope with various housing demands in the changing paradigm of public rental housing. This study focuses on the two-step supply system that has been studied in Japan. It was used to examine and analyze cases to recommend a supply plan that can be used for domestic public rental housing. In more detail, the literature review of the two-step supply system discloses that four types by supply methods (A-1, A-2, B-2, and C-2) and four types of relationship (construction and management combine entities type, management entity type, construction entity type, a separated entity type) can be categorized. In addition, from the actual case study, it revealed that the way of linking and supplying activities among the entity can have a great influence on "ease of supply (supply)", "diversity of housing demand (diversity)," and "quality of construction (construction)". "Ease of supply (supply)" refers to whether the construction entity is separated, and the owner is a manager. "Diversity" refers to whether the management subject is separated, and if the owner is also the constructor or the manager. "Construction" is whether the management entity is connected and managed by the management entity and can be evaluated in "Good", "Middle", and "Bad" level. As a summary, even if the existing public rental housing in Korea can be separated into a skeleton and infill system, the result suggested that it has a limitation on response to residential demand. In addition, the paper was able to propose an improved plan to make the infill as a secondary operator.

• Journal of Practical Engineering Education
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• v.12 no.2
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• pp.339-351
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• 2020

In response to changes in Fourth Industrial Revolution in recent years, the field of education has focused on development of the human resources in the areas of artificial intelligence (AI: Artificial Intelligence) and industrial robot. Due to particular interest in these areas, the importance of developing integrated human resources equipped with artificial intelligence technology is emphasized in higher education and vocational competence development. In regards to rapid changing environment, this study created a program "Fostering personalized AI integrated human resource" and established an operational model correspond to latest personalized education trend. The established operational model was conducted twice using Delphi survey with experts in AI and innovative education in order to verify the suitability of program's basic structure, training process, and the sub-components of the operational strategy. The final training model was applied to the online vocational training platform (STEP) and a plan was proposed to establish a personalized training model to foster an AI integrated competent individual.

• Journal of Ginseng Research
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• v.46 no.5
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• pp.675-682
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• 2022

Background: Korean Red Ginseng (KRG) was reported to play an anti-inflammatory role, however, previous studies largely focused on the effects of KRG on priming step, the inflammation-preparing step, and the anti-inflammatory effect of KRG on triggering, the inflammation-activating step has been poorly understood. This study demonstrated anti-inflammatory role of KRG in caspase-11 non-canonical inflammasome activation in macrophages during triggering of inflammatory responses. Methods: Caspase-11 non-canonical inflammasome-activated J774A.1 macrophages were established by priming with Pam3CSK4 and triggering with lipopolysaccharide (LPS). Cell viability and pyroptosis were examined by MTT and lactate dehydrogenase (LDH) assays. Nitric oxide (NO)-inhibitory effect of KRG was assessed using a NO production assay. Expression and proteolytic cleavage of proteins were examined by Western blotting analysis. In vivo anti-inflammatory action of KRG was evaluated with the LPS-injected sepsis model in mice. Results: KRG reduced LPS-stimulated NO production in J774A.1 cells and suppressed pyroptosis and IL-1β secretion in caspase-11 non-canonical inflammasome-activated J774A.1 cells. Mechanistic studies demonstrated that KRG suppressed the direct interaction between LPS and caspase-11 and inhibited proteolytic processing of both caspase-11 and gasdermin D in caspase-11 non-canonical inflammasome-activated J774A.1 cells. Furthermore, KRG significantly ameliorated LPS-mediated lethal septic shock in mice. Conclusion: The results demonstrate a novel mechanism of KRG-mediated anti-inflammatory action that operates through targeting the caspase-11 non-canonical inflammasome at triggering step of macrophage-mediated inflammatory response.

• Journal of Digital Convergence
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• v.18 no.9
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• pp.191-198
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• 2020

In this study, in order to propose an improvement plan for fire simulation training to improve fire response capability, fire simulation training is conducted for three business facilities, and changes according to whether training materials are used and whether the response time for each response stage is reflected in the training evaluation. The response posture and response ability of the training participants were observed and analyzed. As a result of the analysis, it was analyzed that most of the training participants improved their participation in training, response posture, and response ability when the use of training textbooks and response time for each response stage were reflected in the training evaluation. In the event of a fire simulation training, a number of training materials that can similarly implement the fire situation are used to improve and maintain the fire response capabilities (fire notification and fire report, initial extinguishing, and evacuation) of the training participants, and the target time for each response step. The result was that it can be used as a useful index for improving fire response capability and improving fire simulation training in the future and feedback only when quantitative training evaluation is conducted based on this setting.

• Journal of Power Electronics
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• v.18 no.5
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• pp.1523-1535
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• 2018

High-performance Phase-Locked Loops (PLLs) are critical for grid synchronization in grid-tied power electronic applications. In this paper, a new single-phase All Digital Phase-Locked Loop (ADPLL) is proposed. It features fast transient response and good robustness under distorted grid conditions. It is designed for Field Programmable Gate Array (FPGA) implementation. As a result, a high sampling frequency of 1MHz can be obtained. In addition, a new OSG is adopted to track the power frequency, improve the harmonic rejection and remove the dc offset. Unlike previous methods, it avoids extra feedback loop, which results in an enlarged system bandwidth, enhanced stability and improved dynamic performance. In this case, a new parameter optimization method with consideration of loop delay is employed to achieve a fast dynamic response and guarantee accuracy. The Phase Detector (PD) and Voltage Controlled Oscillator (VCO) are realized by a Coordinate Rotation Digital Computer (CORDIC) algorithm and a Direct Digital Synthesis (DDS) block, respectively. The whole PLL system is finally produced on a FPGA. A theoretical analysis and experiments under various distorted grid conditions, including voltage sag, phase jump, frequency step, harmonics distortion, dc offset and combined disturbances, are also presented to verify the fast dynamic response and good robustness of the ADPLL.

• 한국전산유체공학회:학술대회논문집
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• 2000.05a
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• pp.159-165
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• 2000

In this paper, numerical study has been done for the improvement of the superdetonative ram accelerator performance and for the design optimization of the system. The objective function to optimize the premixture composition is the ram tube length required to accelerate projectile from initial velocity $V_o$ to target velocity $V_e$. The premixture is composed of $H_2,\;O_2,\;N_2$ and the mole numbers of these species are selected at design variables. RSM(Response Surface Methodology) which is widely used for the complex optimization problems is selected as the optimization technique. In particular, to improve the non-linearity of the response and to consider the accuracy and efficiency of the solution, design space stretching technique has been applied. Separate sub-optimization routine is introduced to determine the stretching position and clustering parameters which construct the optimum regression model. Two step optimization technique has been applied to obtain the optimal system. With the application of stretching technique, we can perform system optimization with a small number of experimental points, and construct precise regression model for highly non-linear domain. The error to compared with analysis result is only $0.01\%$ and it is demonstrated that present method can be applied more practical design optimization problems with many design variables.

• Journal of the Korean Society of Safety
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• v.27 no.1
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• pp.86-95
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• 2012

The BWIM(Bridge Weigh-In-Motion) is a technology to identify vehicle properties, such as weight, speed, axle spacing and running lane, passing over a bridge by using dynamic response of bridge member. Such information will be used for assessing durability and establishing a maintenance strategy of roadway structures. In this paper, as a first step for developing BWIM system, analytical and experimental studies were conducted in order to verify whether the response of vertical stiffener in steel girder bridge can be used to identify vehicle properties running on the bridge. It was known from this study that such vehicle information could be estimated reasonably by using strain time history curve of a vertical stiffener due to running vehicles. It is because the effect of each axle-load of vehicle appears definitely in the curve. However, as the magnitude of strain of vertical stiffener is effected by running pattern of vehicles, further study is necessary to reduce error when estimating vehicle weight.

• Structural Engineering and Mechanics
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• v.67 no.4
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• pp.403-415
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• 2018

In the present study, nonlinear dynamic response of polymer-CNT-fiber multiscale nanocomposite plate resting on elastic foundations in thermal environments using the finite element method is performed. In this regard, the governing equations are derived based on Inverse Hyperbolic Shear Deformation Theory and von $K{\acute{a}}rm{\acute{a}}n$ geometrical nonlinearity. Three type of distribution of temperature through the thickness of the plate namely, uniform linear and nonlinear are considered. The considered element is C1-continuous with 15 DOF at each node. The effective material properties of the multiscale composite are calculated using Halpin-Tsai equations and fiber micromechanics in hierarchy. The carbon nanotubes are assumed to be uniformly distributed and randomly oriented through the epoxy resin matrix. Five types of impulsive loads are considered, namely the step, sudden, triangular, half-sine and exponential pulses. After examining the validity of the present work, the effects of the weight percentage of SWCNTs and MWCNTs, nanotube aspect ratio, volume fraction of fibers, plate aspect, temperature, elastic foundation parameters, distribution of temperature and shape of impulsive load on nonlinear dynamic response of CNT reinforced multi-phase laminated composite plate are studied in details.