• Journal of Electrical Engineering and Technology
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• 제5권1호
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• pp.16-20
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• 2010

Recently, the smart grid has become a hot issue and interest in related power sources have increased accordingly. The implementation of a smart grid can enable many generation resources to be linked to the power system, including small-scale reactors for the purpose of co-generation. Research on small-scale reactors is being carried out all over the world. Similarly, Korea is also conducting research on multi-purpose regional energy systems using nuclear energy. This paper proposes a real-time data acquisition and analysis system for small-scale reactors, and is known as the REX-10 (Regional Energy rX 10 MVA). This analysis requires real-time simulations for the power system since it needs data communication with a remote REX-10. A RTDS (Real Time Digital Simulator) has been used for the simulation, and a SCADA/HMI system interfaced with the RTDS is proposed for the purpose of monitoring and control of the regional energy system.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제18권3호
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• pp.551-569
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• 2024

With the rapid development of electric vehicles (EVs) industry, EV charging service becomes more and more important. Especially, in the case of suddenly drop of air temperature or open holidays that large-scale EVs seeking for charging devices (CDs) in a short time. In such scenario, inefficient EV charging scheduling algorithm might lead to a bad service quality, for example, long queueing times for EVs and unreasonable idling time for charging devices. To deal with this issue, this paper propose a Deep-Q-Network (DQN) based two-stage scheduling method for the large-scale EVs charging service. Fine-grained states with two delicate neural networks are proposed to optimize the sequencing of EVs and charging station (CS) arrangement. Two efficient algorithms are presented to obtain the optimal EVs charging scheduling scheme for large-scale EVs charging demand. Three case studies show the superiority of our proposal, in terms of a high service quality (minimized average queuing time of EVs and maximized charging performance at both EV and CS sides) and achieve greater scheduling efficiency. The code and data are available at THE CODE AND DATA.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 춘계학술대회논문집
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• pp.1276-1279
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• 2006

This article on environmental noise qualify is concerned with the relationships between the annoyance and perception and sound quality metrics according to exposition time for traffic noise. For invested the characteristics of noise quality, we conducted to the subjective experiments of the annoyance response using the absolute 100 scaling method for the traffic noise sources. The traffic noise sources are composed to varieties exposition time from 15sec to 1200sec. As the results, the first there are decreased the perception loud level for the increase of exposition time with logarithm scale, but increased the annoyance. Second, evaluation index of annoyance is correlated to the loudness(sones), tonality and logarithm scale time with R2=0.83. Also, the composition ratio of traffic noise according to exposition time has the change of range as the logarithm scale ($30{\sim}50%$), tonality($27{\sim}37%$) and loudness($34{\sim}20%$).

• 대한기계학회논문집B
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• 제20권3호
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• pp.1040-1049
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• 1996

The high loading combustion is accomplished by making the turbulent intensity strong and the scale small in the premixed combustor. The Da-mkoler number, which is decreased by short turbulent characteristic time or by long chemical reaction time, can make the distributed reaction flame. So we developed a doubled jet burner for high loading combustion. The doubled jet burner was designed to make the scale of the flame small by the effect of impingement and increasing shear stress with doubled jet. We investigated the turbulence characteristics of unburned mixture and visualized several flames with the typical schlieren photography. Then we studied the influence of several factors that related the scale of flame. Consequently, the doubled jet burner can make the eddy very small. And we can obtain the detail information of the flame scale through ADSF(the Average Distance between Successive Fringes) in the micro- schlieren photography. The ADSF is not a exact flame scale, but it has qualitative trend with increasing turbulent intensity. The ADSF is diminished remarkably with increasing turbulent intensity. The reason is that strong turbulent intensity makes the flame zone thick and flamelets numerous. We can confirm this fact by the signal analysis of ion currents.

• 한국음향학회지
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• 제21권3호
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• pp.293-303
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• 2002

본 논문에서는 ITU G.729 음성 복호화기와 듀얼 SOLA (Synchronized Overlap-Add)알고리듬을 통합한 최적의 음성 속도 변환시스템 (TSM)을 구현한다. 제안된 시스템은 ITU G.729 음성 복호화기를 통한 8 Khz 80 샘플/프레임 단위의 음성 신호를 입력으로 가정하여 듀얼 SOLA를 통해 사용자가 원하는 음성 속도에 맞추어 출력, 음성을 천천히 혹은 빠르게 최적화된 음성 품질로의 재생을 가능하게 한다. 특히 본 논문에서 제안된 듀얼 SOLA는 다양한 SOLA 파라미터에 대한 모의실험과 이론적 분석에 의거하여 ITU G.729 복호화기 음성 신호에 대한 최적화된 음성 재생 변환 기능을 제공하며, 입력 음성신호의 부가적인 인터폴레이션 (interpolation) 과정을 첨가하여 최대 2배 빠르기 혹은 2배 느리기의 극한 속도율에서도 우수한 성능의 통합 음성 속도 변환 시스템을 구현할 수 있다. 제안된 시스템은 다양한 입력 음성신호와 재생 속도에 대한 모의실험을 걸쳐 그 성능을 검증한다.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제14권4호
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• pp.305-312
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• 2014

This paper discusses real-time peak shaving algorithms for a large-scale battery energy storage system (BESS). Although several transmission and distribution functions could be implemented for diverse purposes in BESS applications, this paper focuses on a real-time peak shaving algorithm for an energy time shift, considering wind power generation. In a high wind penetration environment, the effective load levels obtained by subtracting the wind generation from the load time series at each long-term cycle time unit are needed for efficient peak shaving. However, errors can exist in the forecast load and wind generation levels, and the real-time peak shaving operation might require a method for wind generation that includes comparatively large forecasting errors. To effectively deal with the errors of wind generation forecasting, this paper proposes a real-time peak shaving algorithm for threshold value-based peak shaving that considers fuzzy wind power generation.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2005년도 International Meeting on Information Displayvol.II
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• pp.1347-1350
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• 2005

A modified Time-Ratio Gray Scale AMOLED drive technique is described in which the frame period is split into two half-frames, each of which is divided into binary weighted sub-frames and driven in the conventional time-ratio manner. The proposed technique improves aperture ratio by reducing TFT sizes in pixel circuits.

• Journal of Mechanical Science and Technology
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• 제17권2호
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• pp.197-206
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• 2003

It is intended to retrieve the time history of displacement from measured acceleration signal. In this study, the word retrieving means reconstructing the time history of original displacement signal from already measured acceleration signal not just extracting various information using relevant signal processing techniques. Unlike extracting required information from the signal, there are not many options to apply to retrieve the time history of displacement signal, once the acceleration signal is measured and recorded with given sampling rate. There are two methods, in general, to convert measured acceleration signal into displacement signal. One is directly integrating the acceleration signal in time domain. The other is dividing the Fourier transformed acceleration signal by the scale factor of - $\omega$$^2$and taking the inverse Fourier transform of it. It turned out both the methods produced a significant amount of errors depending on the sampling resolution in time and frequency domain when digitizing the acceleration signals. A simple and effective way to convert the time history of acceleration signal into the time history of displacement signal without significant errors is studied here with the analysis on the errors involved in the conversion process.

• 한국항공우주학회지
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• 제30권2호
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• pp.91-97
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• 2002

응축영역 에너지 방정식과 기체 영역에 관한 화염모델을 사용하여 연소실 압력 강하에 반응하는 고체 추진제의 동적 소화 특성을 살펴보았다. 화염모델에서는 기체가 반응영역을 통과하는데 걸리는 시간(잔존시간, r,)이 동적 소화 특성을 결정하는 중요한 인자임을 확인하였다. 본 논문에서는 r,을 확산과 화학반응 시간의 다양한 조합으로 가정하였으며 이를 이용하여 동적 소화 특성을 살펴보았다. 또한 연소실 부피의 유한함에 따른 압력변화와 이에 대한 연소의 동적 반응도 살펴보았다. 동적 소화는 화학반응 시간보다는 확산 시간에 의하여 커다란 영향을 받는 현상임을 확인하였다. 그리고 연소실 부피가 유한한 경우가 무한한 경우보다 복잡한 동적 소화 특성을 보여주었다.

• 기본간호학회지
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• 제6권1호
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• pp.51-63
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• 1999

This study examined two differences in physical and psychological recovery patterns after surgery in the elderly. The sample consisted of 40 patients with abdominal surgery In five large hospitals in Seoul. The data for this study were collected from Apr. 20 to Nov. 26 by structured questionnaire, chart review and call. Physical recovery was assessed by ADL, a Cantril Ladder Scale and a Visual Analogue Scale. Psychological recovery was measured by the Geriatric depression Scale and a Cantril Ladder Scale. The data were analyzed using frequency, percentage, Pearson Correlation Coefficient, and MANOVA by SPSS/WIN. The result are as follows : 1. Physical recovery indicated significant improvement over time with the exception of ADL(F=.812 p=.449). Perceived physical health were significantly improved(F=6.189 p=.004). Pain & discomfort was significantly decreased(F=3.927 p=.025). 2. Perceived psychological health was significantly improved over time(F=20.648 p=.000), but depression showed no statistical significance improvement over time(F=1.393 p=.256). 3. There were no significant effects of sex, age, complication and combined chronic diseases on physical and psychological recovery patterns. 4. There were significant correlations between operation time and pain(r=-.331 p=.020), recovery time and perceived psychological health(r=-.320 p=.024), recovery time and pain(r=.404 p=.005). There were significant correlations between admision period and ADL(r=-.418 p=.004), perceived physical health(r=-.354 p=.014), depression(r=.280 p=.042), and perceived psychological health(r=-.447 p=.002). BRAS showed significant correlation with ADL(r=-.458 p=.002). 5. With an increase in the degree of perceived health(physical and psychological), ADL was significantly increased. With an increased in the degree of depression and pain, ADL and perceived health(physical and psychological) were significantly decreased. In conclusion, the elderly patient recovered significantly over time with the exception of ADL and depression. It these we suggested to considered when planning care for elderly patients.