• 전기학회논문지
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• 제66권9호
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• pp.1364-1372
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• 2017

In this paper, a problem of event-triggered model predictive control is investigated for continuous-time Takagi-Sugeno (T-S) fuzzy systems with input quantization. To efficiently utilize network resources, event-trigger is employed, which transmits limited signals satisfying the condition that the measurement of errors is over the ratio of a certain level. Considering sampling and quantization, continuous Takagi-Sugeno (T-S) fuzzy systems are regarded as a sector bounded continuous-time T-S fuzzy systems with input delay. Then, a model predictive controller (MPC) based on parallel distributed compensation (PDC) is designed to optimally stabilize the closed loop systems. The proposed MPC optimize the objective function over infinite horizon, which can be easily calculated and implemented solving linear matrix inequalities (LMIs) for every event-triggered time. The validity and effectiveness are shown that the event triggered MPC can stabilize well the systems with even smaller average sampling rate and limited actuator signal guaranteeing optimal performances through the numerical example.

• 한국물환경학회지
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• 제25권1호
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• pp.125-135
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• 2009

Reliable long-term flows by SWAT-K model were applied to the relationship between stream flow and pollutant load derived from 8-day measured data of Ministry of Environment (MOE) in order to obtain continuous loadograph and evaluate accuracy in water quality modeling for the Chungju dam watershed. The measured flow were compared with flow duration curve from the model, and it showed that measured values corresponded to the almost full range of stream flow conditions except at Odae A. And there was significant relationship ($R^2=0.60{\sim}0.97$) between measured flow and water quality load at all unit-watersheds. Applying this relationship to simulated flows, continuous loadograph was obtained and compared with modeled pollutant loads. Although there were some differences during some dry and flood seasons, those were not significant and overall trend showed a good agreement. From the results, we would be able to derive a continuous loadograph based on measured data at total maximum daily loads (TMDLs) unit-watersheds on a national scale, in which stream flow and water quality have been measured at 8-day intervals since 2004, and this could be helpful to utilize distributed water quality models with difficulty in calibrating and validating parameters from lack of measured data at present.

• 한국정보시스템학회지:정보시스템연구
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• 제33권1호
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• pp.91-114
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• 2024

Purpose The purpose of this study is to empirically investigate the factors that influence users' continuous intention to use ChatGPT based on the Expectation Confirmation Model(ECM). Drawing from the literature, this study identifies anthropomorphism and trust as key characteristics of generative AI and ChatGPT. Design/methodology/approach The research model was developed based on ECM and literature research to investigate the impacts of anthropomorphism and trust on continuous intention of using ChatGPT. In order to test the hypothese, a total of 193 questionnaires were collected and analyzed for the structural equation modeling with SmartPLS 4.0. Findings The study's findings show that all proposed hypotheses were supported, suggesting that the ECM is a valid framework for examining continuous intention of using ChatGPT. Moreover, the study stressed the crucial role of anthropomorphism in the model, showing the positive impact on expectation confirmation, perceived usefulness, and trust in ChatGPT. Also, trust positively affects perceived usefulness. These findings provide valuable insights for enhancing user satisfaction and continuous usage intention, serving as a foundation for development strategies for ChatGPT and similar AI-based systems.

• The Korean Journal of Physiology and Pharmacology
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• 제28권2호
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• pp.121-127
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• 2024

Vancomycin is a frequently used antibiotic in intensive care units, and the patient's renal clearance affects the pharmacokinetic characteristics of vancomycin. Several advantages have been reported for vancomycin continuous intravenous infusion, but studies on continuous dosing regimens based on patients' renal clearance are insufficient. The aim of this study was to develop a vancomycin serum concentration prediction model by factoring in a patient's renal clearance. Children admitted to our institution between July 1, 2021, and July 31, 2022 with records of continuous infusion of vancomycin were included in the study. Sex, age, height, weight, vancomycin dose by weight, interval from the start of vancomycin administration to the time of therapeutic drug monitoring sampling, and vancomycin serum concentrations were analyzed with the linear regression analysis of the mixed effect model. Univariable regression analysis was performed using the vancomycin serum concentration as a dependent variable. It showed that vancomycin dose (p < 0.001) and serum creatinine (p = 0.007) were factors that had the most impact on vancomycin serum concentration. Vancomycin serum concentration was affected by vancomycin dose (p < 0.001) and serum creatinine (p = 0.001) with statistical significance, and a multivariable regression model was obtained as follows: Vancomycin serum concentration (mg/l) = -1.296 + 0.281 × vancomycin dose (mg/kg) + 20.458 × serum creatinine (mg/dl) (adjusted coefficient of determination, R² = 0.66). This prediction model is expected to contribute to establishing an optimal continuous infusion regimen for vancomycin.

• Korean Chemical Engineering Research
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• 제43권2호
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• pp.278-285
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• 2005

연속식 유동층 반응기에서 흡착제인 천연망간광석을 이용한 탈황반응과, grain model과 two-phase 이론에 근거한 탈황 모사를 연구하였다. 입자 내의 기공 구조변화를 고려한 grain model을 통하여 탈황 반응시간, 천연망간광석의 입자 크기, 기공 내에서 $SO_2$의 확산속도에 대한 영향을 고찰한 결과, 입자의 기공 내에서 $SO_2$ 가스 확산이 탈황 반응의 가장 중요한 요소로 나타났다. 또한, 연속식 유동층 반응기에서 흡착제인 천연망간광석을 이용한 탈황반응 실험결과는 grain model과 two-phase 이론과 잘 일치하였으며, 탈황 결과를 잘 예측할 수 있었다.

• 정보처리학회논문지A
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• 제8A권3호
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• pp.217-226
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• 2001

본 논문은 클러스터 기반의 분산 구조를 갖는 CCMSS(Clustered Continuous Media Storage Server) 시스템의 미디어 검색 동작에 대해 디스크의 입출력 지연 시간 뿐맘 아니라 내부 네트워크의 통신 지연 시간을 함께 고려한, 열린 큐잉 네트워크 기반의 해석적 모델을 제시하고 이를 이용하여 전체 서비스 지연 시간에 대한 확률적 모델을 정의한다. 그리고 정의된 확률적 모델을 바탕으로 허용된 서비스 실패율 범위에서 최대 서비스 가능한 사용자 요구 수를 구하고 이 값을 이용하여 승인 제어를 수행하는 통합형 통계적 승인 제어 모델을 제안한다. 제안된 승인 제어 기법의 성능 분석을 위해 단순히 디스크 성능만을 고려한 확률적 모델과 본 논문에서 제안한 디스크 성능과 내부 네트워크의 성능을 함께 고려한 확률적 모델을 통해 산출한 마감시간 실패율과 실제 클러스터 기반 서버 환경에서 모의 실험을 통해 얻은 결과를 비교하였으며, 실험 결과에 대한 분석을 통해 제안된 승인 제어 기법이 CCMSS 시스템의 실제 서비스 지연 요소를 정확히 반영하고 있다는 것을 알 수 있었다.

• Earthquakes and Structures
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• 제22권6호
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• pp.609-623
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• 2022

To study the empirical seismic fragility of a reinforced concrete girder bridge, based on the theory of numerical analysis and probability modelling, a regression fragility method of a rapid fragility prediction model (Gaussian first-order regression probability model) considering empirical seismic damage is proposed. A total of 1,069 reinforced concrete girder bridges of 22 highways were used to verify the model, and the vulnerability function, plane, surface and curve model of reinforced concrete girder bridges (simple supported girder bridges and continuous girder bridges) considering the number of samples in multiple intensity regions were established. The new empirical seismic damage probability matrix and curve models of observation frequency and damage exceeding probability are developed in multiple intensity regions. A comparative vulnerability analysis between simple supported girder bridges and continuous girder bridges is provided. Depending on the theory of the regional mean seismic damage index matrix model, the empirical seismic damage prediction probability matrix is embedded in the multidimensional mean seismic damage index matrix model, and the regional rapid prediction matrix and curve of reinforced concrete girder bridges, simple supported girder bridges and continuous girder bridges in multiple intensity regions based on mean seismic damage index parameters are developed. The established multidimensional group bridge vulnerability model can be used to quantify and predict the fragility of bridges in multiple intensity regions and the fragility assessment of regional group reinforced concrete girder bridges in the future.

• 융합경영연구
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• 제11권5호
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• pp.29-44
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• 2023

Purpose: This study analyzed the effect of the perceived value of the OTT platform on consumers' technology acceptance, continuous use intention, and WOM using the Expanded TAM. Research design, data and methodology: A survey was conducted targeting OTT platform users in their 20s to 40s nationwide from August 10 to 16, 2022, and a total of 208 people were used in the final analysis. To verify the research model, frequency analysis, CFA, and SEM analysis were performed using SPSS and AMOS. Results: First, the perceived value of the OTT platform was found to have a positive effect on consumers' technology acceptance (perceived usefulness, perceived ease of use, and perceived enjoyment). Second, the perceived ease of use of OTT platform consumers was found to have a positive effect on perceived usefulness and perceived enjoyment. Third, it was found that the perceived usefulness and perceived enjoyment of OTT platform consumers had a positive effect on the continuous use intention, and WOM. Fourth, it was found that the continuous use intention the OTT platform had a positive effect on the WOM. Conclusions: Word of mouth and continuous use of existing customers are important for OTT platform companies to retain existing customers and secure new customers. Through the perceived value of the OTT platform, efforts should be made to provide various contents that consumers can enjoy along with usefulness and convenience of functions.

• Asia pacific journal of information systems
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• 제32권2호
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• pp.249-274
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• 2022

This study is to focuses on users' attitudes toward augmented reality games. Based on the Technology Acceptance Model (TAM) and Flow theory, continuous usage intention was set as a dependent variable, and immersion was set as a mediating variable. As independent variables, spatial presence, perceived interactivity, perceived pleasure, and sickness were set. Besides, this study strived to compare and analyze Korean and Chinese Data. The results of this study were as follows. First of all, Korean users significantly affected spatial presence, perceived pleasure, and immersion. Spatial presence and perceived pleasure had also mediated effects on continuous usage intention through immersion. However, perceived interactivity and sickness did not affect immersion and even no mediating effect to continuous usage intention. In the case of Chinese users, spatial presence, perceived interactivity, and perceived pleasure were grouped into one variable. This variable influenced immersion and also had mediated effect on continuous usage intention. However, sickness, like Korean users, did not affect the set path. This study had implications for analyzing user perspective using immersion, a significant variable in previous research. In addition, this study found similarities and characteristics through a comparative analysis between Korean and Chinese users indirectly.

• 콘크리트학회논문집
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• 제23권1호
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• pp.3-12
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• 2011

철근콘크리트 깊은 보의 거동은 전단경간비, 휨철근비, 하중점과 지지점의 조건, 그리고 사용재료의 성질 등의 여러 변수간의 복합적인 역학관계로 인해 매우 복잡하다. 이 논문에서는 이러한 깊은 보의 거동 특성을 모두 반영하여 연속지지 철근콘크리트 깊은 보의 설계를 수행할 수 있는 부정정 스트럿-타이 모델을 제안하였다. 또한 현 스트럿-타이 모델 설계기준을 부정정 스트럿-타이 모델을 이용한 연속지지 철근콘크리트 깊은 보의 설계에 합리적으로 적용하기 위해 외부하중에 대한 단부 지지점 반력의 비인 반력분배율과 수직 트러스 메커니즘에 의해 전달되는 외부하중의 크기 즉 부정정 스트럿-타이 모델의 하중분배율을 제안하였다. 하중분배율의 결정 시 연속지지 철근콘크리트 깊은 보의 전단에 대한 연성파괴거동을 확보하기 위하여 깊은 보의 전단저항 메커니즘을 구성하는 콘크리트 스트럿과 수직철근타이가 동시에 파괴된다는 전단평형철근비 개념을 도입하였으며, 다양한 수치해석 결과를 바탕으로 연속지지 깊은 보의 강도 및 거동에 영향을 미치는 전단경간비, 휨철근비, 그리고 콘크리트의 압축강도 등의 주요설계변수를 고려하였다. 이 논문의 후속편에서는 기존의 여러 설계방법들과 이 연구에서 제안한 방법을 이용하여 파괴실험이 수행된 다양한 종류의 연속지지 깊은 보의 강도를 평가하고, 이 연구에서 제안한 방법의 적합성을 검증하였다.