• Journal of Power Electronics
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• 제16권5호
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• pp.1821-1832
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• 2016

This study presents a strategy using the synchronized output regulation method (SOR) for controlling inverters operating in stand-alone and grid-connected modes. From the view point of networked dynamic systems, SOR involves nodes with outputs that are synchronized but also display a desirable wave shape. Under the SOR strategy, the inverter and grid are treated as two nodes that comprise a simple network. These two nodes work independently under the stand-alone mode. An intermediate mode, here is named the synchronization mode, is emphasized because the transition from the stand-alone mode to the grid-connected mode can be dealt as a standard SOR problem. In the grid-connected mode, the inverter operates in an independent way, in which the voltage reference changes for generalized synchronization where its output current satisfies the required power injection. Such a relatively independent design leads to a seamless transfer between operation modes. The closed-loop system is analyzed in the state space on the basis of the output regulation theory, which improves the robustness of the design. Simulations and experiments are performed to verify the proposed control strategy.

• 반도체디스플레이기술학회지
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• 제22권4호
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• pp.13-18
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• 2023

A subway station is a prominent multi-purpose facility where the quantitative management of fine dust, generated by various factors, is conducted. Recently, eco-friendly air purification methods using air-purifying plants are being discussed, with the focus on biofiltration through vegetation. Previous research in this field has confirmed the reduction effects of transition metals such as Fe, which have been identified as harmful to human health. This study aimed to identify the sources of fine dust dispersion within subway stations and derive an efficient operational strategy for air-purifying plants that takes into account the behavior characteristics of fine dust within multi-purpose facilities. The experiment monitored regional fine dust levels through IAQ stations established based on prior research. Also, the data was analyzed through time-series and correlation analyses by linking it with passenger counts at subway stations and the frequency of train stops. Furthermore, to consider energy efficiency, we conducted component-specific power consumption monitoring. Through this study, we were able to derive the optimal operational strategy for air-purifying plants based on time-series comprehensive analysis data and confirm significant energy efficiency.

• 여성건강간호학회지
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• 제28권3호
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• pp.210-221
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• 2022

Purpose: The purpose of this study was to construct a hypothetical model based on Meleis and colleagues' Transition Theory and a literature review to explain women's menopausal transition, constructing a modified model considering previous studies and model fit and testing the effects between variables. Methods: With a correlational survey design, middle-aged Korean women aged 40 to 64 years who had experienced menopausal symptoms were recruited and filled out a self-administered study questionnaire. Measures included menopausal symptoms, resilience, social support, menopause management, menopause adaptation, and quality of life. The data were analyzed using SPSS 24.0 and AMOS 24.0. Results: The model fit indices were considered acceptable: 𝛘²/degree of freedom=2.93, standardized root mean residual=.07, comparative fit index=.90, and parsimonious normed fit index=.73. All eight direct-effect paths-from menopausal symptoms to support and adaptation, from support to adaptation and resilience, from resilience to adaptation and management, from management to quality of life, and from adaptation to quality of life-were significant. The explanatory power of the menopause transition model was 63.6%. Conclusion: Women who experience menopausal symptoms may be able to maintain and improve their quality of life if menopause management and menopause adaptation are successful through resilience and social support. Future research is needed to confirm whether strengthening facilitation as a nursing intervention strategy may promote healthy response patterns.

• STI Policy Review
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• 제7권1호
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• pp.1-16
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• 2016

Technology supply has been the main thrust of the Korean government's science & technology policy, focusing on the development and acquisition of new technology in line with the catching-up strategy of economic growth and industrial development. However, new social or societal problems have become major government policy issues, heralding new innovation policy aimed to address them. Such new policy initiatives for social problem-solving present a niche where the existing system of government innovation policy process is challenged, including such processes as goal-setting, planning, implementation, project management, and evaluation. The rigidity of the existing institution of government innovation policy, however, still shapes the content and progression of innovation policy for social problem-solving. This study reviews Korean innovation policy for social problem-solving as a policy niche, and aims to clarify its challenges and opportunities. It uses a system transition framework to explain the emergence and evolution of the innovation policy niche in Korea. The main research question is to what extent and in what aspect the existing innovation policy regime shaped innovation policy for social problem-solving. The study examines the inertia of the current paradigm of innovation policies and R&D programs, and sheds light on the search for a distinctive identity for innovation policies that tackles social problems.

• Molecules and Cells
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• 제37권5호
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• pp.383-388
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• 2014

Renal cell carcinoma (RCC) is associated with a high frequency of metastasis and only few therapies substantially prolong survival. Honokiol, isolated from Magnolia spp. bark, has been shown to exhibit pleiotropic anticancer effects in many cancer types. However, whether honokiol could suppress RCC metastasis has not been fully elucidated. In the present study, we found that honokiol suppressed renal cancer cells' metastasis via dual-blocking epithelial-mesenchymal transition (EMT) and cancer stem cell (CSC) properties. In addition, honokiol inhibited tumor growth in vivo. It was found that honokiol could upregulate miR-141, which targeted ZEB2 and modulated ZEB2 expression. Honokiol reversed EMT and suppressed CSC properties partly through the miR-141/ZEB2 axis. Our study suggested that honokiol may be a suitable therapeutic strategy for RCC treatment.

• Journal of international Conference on Electrical Machines and Systems
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• 제1권2호
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• pp.64-69
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• 2012

This paper presents a hybrid pulse width modulation (PWM) method under low switching frequency conditions based on space vector PWM (SVPWM) and selective harmonic eliminated PWM (SHEPWM), which use asynchronous carrier modulation SVPWM at low frequency, and SHEPWM at high frequency, a square wave after rated conditions. A transitive strategy is proposed to realize a smooth transition of individual modes including SVPWM, SHEPWM and square waves. Experimental results confirm this hybrid modulation method and their transition are reasonable and proper.

• Journal of Information Technology Applications and Management
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• 제15권3호
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• pp.43-59
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• 2008

This paper studies small and medium sized financial agency's management states that take advantage of the Korea Federation of Saving Bank's data. It also presents the management state and the decision-making model that monitors progressive insolvency by standardizing transfer path between relevant groups. With this in mind, we extracted explanatory variables for predictions of insolvency by using existing studies of document related insolvency. First of all, we designed a state model based on demarcated groups to take advantage of the self organizing map that groups in line with a neural network. Secondly, we developed a transition model by standardizing the transfer path between individual banks in a state model. Finally, we presented a decision-making model that integrated the state model and the transition model. This paper will provide groundwork for methods of insolvency prevention to businesses in order for them to have a smooth management system in the financial agencies.

• 한국데이타베이스학회:학술대회논문집
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• 한국데이타베이스학회 2010년도 춘계국제학술대회
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• pp.187-199
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• 2010

Recently, Internet Telephony has become increasingly popular in telecommunication industry. However, previous research on Internet Telephony has focused on analyzing specific Internet Telephony solutions, identifying the Internet Telephony movement itself. The research on prediction models about Internet Telephony adoption has been minimal. The main propose of this study is to develop models for predicting transition intention from using traditional telephones to using Internet Telephony. To do so, this study uses data mining methods to analyze demands in the IT communications market and to provide management strategies for Internet telephony providers. Especially this study uses discriminant analysis, logistic regression, classification tree, and neural nets to develop the prediction models for the Internet Telephony adoption. The models are compared with each other and a superior model is chosen.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1998년도 Proceedings ICPE 98 1998 International Conference on Power Electronics
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• pp.694-700
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• 1998

A novel zero-voltage-transition (ZVT) isolated PWM boost converter for single stage power factor correction (PFC) is presented to improve the performance of the previously presented ZVT converter[8]. A simple auxiliary circuit which includes only one active switch provides zero-voltage-switching (ZVS) condition to all semiconductor devices. (Two active switches are required for the previous ZVT converter) This leads to reduced cost and simplified control circuit comparing to the previous ZVT converter. The ZVS is achieved for wide line and load ranges with minimum device voltage and current stresses. Operation principle, control strategy and features of the proposed converter are presented and verified by the experimental results from a 1.5 kW, 100 KHz laboratory prototype.

• 한국세라믹학회지
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• 제55권4호
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• pp.307-324
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• 2018

Rechargeable lithium-ion batteries (LIBs) have been rapidly expanding from IT based applications to uses in electric vehicles (EVs), smart grids, and energy storage systems (ESSs), all of which require low cost, high energy density and high power density. The increasing demand for LIBs has resulted in increasing price of the lithium source, which is a major obstacle to wider application. To date, the possible depletion of lithium resources has become relevant, giving rise to the interest in Na-ion batteries (NIBs) as promising alternatives to LIBs. A lot of transition metal compounds based on conversion-alloying reaction have been extensively investigated to meet the requirement for the anodes with high energy density and long life-time. In-depth understanding the electrochemical reaction mechanisms for the transition metal compounds makes it promising negative anode for NIBs and provides feasible strategy for low cost and large-scale energy storage system in the near future.