• 대한의용생체공학회:의공학회지
• /
• 제16권4호
• /
• pp.415-424
• /
• 1995

Combined models, specified by two or more modeling formalisms, can represent a wide variety of complex systems. This paper describes a methodology for the development of combined models in two model types of discrete event and continuous process. The methodology is based on transformation of continuous state space into discrete one to homomorphically represent dynamics of continuous processes in discrete events. This paper proposes a formal structure which can combine model of the DES and the CS within a framework. The structure employs the DEVS formalism for the DES models and differential or polynomial equations for the CS models. To employ the proposed structure to specify a DEVS/CS combined model, a modeler needs to take the following steps. First, a modeler should identify events in the CS and transform the states of the CS into the DES. Second, a modular employs the formalism to specify the system as the DES. Finally, a moduler developes sub-models for the CS and continguos states of the DES and establishs one-to-one correspondence between the sub-models and such states. The proposed formal structre has been applied to develop a DEVS/CS combined model for the human cardiovascular system. For this, the cardiac cycle is partitioned into a set of phases based on events identified through observation. For each phase, a CS model has been developed and associated with the phase. To validate the DEVS/CS combined model developed, then simulate the model in the DEVSIM + + environment, which is a model simulation results with the results obtained from the CS model simulation using SPICE. The comparison shows that the DEVS/CS combined model adequately represents dynamics of the human heart system at each phase of cardiac cycle.

• 대한가정학회지
• /
• 제23권1호
• /
• pp.59-69
• /
• 1985

Consumer satisfaction/dissatisfaction is a concept which is receiving increased attention from consumers, public policy makers, and marketers alike. The literature in this field is still meager, has been growing rapidly byt with diversity of direction. The purpose of this study is to review the conceptualization and taxonomy of CS/D in consumer research. Three types of the basic process in a general theory of CS/D are suggested; system CS/D, enterprise CS/D and product-service CS/D. It is also classified into macro marketing system CS/D, micro marketing system CS/D and consuming mix CS/D. The conceptualization of CS/D begins with a basic model of how CS/D results from the individual product purchase experience of individual consumer. Basic CS/D models are classified into process model which contains experience, information search, prepurchase evaluation and comparison process variables and psychological model which is derived from cognitive dissonance theory. Theoretical and empirical foundations about expectation model are asimilatin, contrast, generalized negativity and assimilation contrast theories.

• 품질경영학회지
• /
• 제49권3호
• /
• pp.421-431
• /
• 2021

Purpose: For improving outgoing quality, this study presents a novel sampling framework based on predictive analytics. Methods: The proposed framework is composed of three steps. The first step is the variable selection. The knowledge-based and data-driven approaches are employed to select important variables. The second step is the model learning. In this step, we consider the supervised classification methods, the anomaly detection methods, and the rule-based methods. The applying model is the third step. This step includes the all processes to be enabled on real-time prediction. Each prediction model classifies a product as a target sample or random sample. Thereafter intensive quality inspections are executed on the specified target samples. Results: The inspection data of three Samsung products (mobile, TV, refrigerator) are used to check functional defects in the product by utilizing the proposed method. The results demonstrate that using target sampling is more effective and efficient than random sampling. Conclusion: The results of this paper show that the proposed method can efficiently detect products that have the possibilities of user's defect in the lot. Additionally our study can guide practitioners on how to easily detect defective products using stratified sampling

• Computers and Concrete
• /
• 제21권1호
• /
• pp.103-110
• /
• 2018

This study introduces the supervised committee fuzzy model as a hybrid fuzzy model to predict compressive strength (CS) of geopolymers prepared from alumina-silica products. For this purpose, more than 50 experimental data that evaluated the effect of $Al_2O_3/SiO_2$, $Na_2O/Al_2O_3$, $Na_2O/H_2O$ and Na/[Na+K] on (CS) of geopolymers were collected from the literature. Then, three different Fuzzy Logic (FL) models (Sugeno fuzzy logic (SFL), Mamdani fuzzy logic (MFL), and Larsen fuzzy logic (LFL)) were adopted to overcome the inherent uncertainty of geochemical parameters and to predict CS. After validating the model, it was found that the SFL model is superior to MFL and LFL models, but each of the FL models has advantages to predict CS. Therefore, to achieve the optimal performance, the supervised committee fuzzy logic (SCFL) model was developed as a hybrid method to combine the benefits of individual FL models. The SCFL employs an artificial neural network (ANN) model to re-predict the CS of three FL model predictions. The results also show significant fitting improvement in comparison with individual FL models.

• 대한환경공학회지
• /
• 제39권2호
• /
• pp.66-73
• /
• 2017

본 연구에서는 제올라이트 X를 이용한 Cs 이온 흡착시 흡착시간 및 초기농도, 온도 및 pH 변화와 같은 영향인자를 평가하였다. 이 결과로부터 Cs 이온의 흡착속도, 등온흡착량 및 열역학적 특성을 해석하였다. 제올라이트 X에 의한 Cs 이온의 흡착은 pH 5~10에서 효과적이었으며, 평형흡착시간은 약 60분이었다. 흡착속도와 등온흡착량은 유사 2차 속도 모델식과 Langmuir 식에 잘 적용되었다. Langmuir 식으로 구한 Cs 이온의 최대 흡착량은 293~333 K에서 각각 303.03~333.33 mg/g이었다. 제올라이트 X에 의한 Cs 이온의 흡착은 흡열반응이고 자발적인 반응이었다. 실험값을 다중회귀분석으로 최적화하여 2차 다항식을 얻었다. 이 최적화된 식으로부터 구한 종속변수의 값과 실험에서 구한 값은 잘 일치하였다.

• 대한본초학회지
• /
• 제22권3호
• /
• pp.57-65
• /
• 2007

Objectives : We examined to know the effect of Cordyceps sinensis(CS) on arthritis mouse induced by type II collagen. Methods : To analyse immunomodulatory effects of CS, arthritis index, incidence, hind paw edema, DTH, spleen weight, the number of hemocytes, and surface-receptor expression of CD4+, CD8+ and CD19+ cells in DBA/IJ mice which is experimental model of arthritis induced by collagen were measured in vivo. Results: CS reduced arthritis index, incidence, hind paw edema and DTH significantly as compared with the control group in experimental model of arthritis induced by collagen. CS enhanced the spleen weight significantly as compared with the control group but didn't enhanced the number of leukocytes and thrombocytes in experimental model of arthritis. CS enhanced the number of activating cells and surface-receptor expression of CD4+, CD8+ cells as compared with the control group but didn't enhanced those of CD19+ cells in experimental model of arthritis. Conclusion : We found out that CS may have a suppressing effect againist auto-immune disease and will be need continuous research in looking for the more effective mechanism in the future.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제7권2호
• /
• pp.366-385
• /
• 2013

In this paper, we propose a compressed sensing (CS) based Wyner-Ziv (WZ) codec using motion-aligned auto regressive model (MAAR) based side information (SI) extrapolation to improve the compression performance of low-delay distributed video coding (DVC). In the CS based WZ codec, the WZ frame is divided into small blocks and CS measurements of each block are acquired at the encoder, and a specific CS reconstruction algorithm is proposed to correct errors in the SI using CS measurements at the decoder. In order to generate high quality SI, a MAAR model is introduced to improve the inaccurate motion field in auto regressive (AR) model, and the Tikhonov regularization on MAAR coefficients and overlapped block based interpolation are performed to reduce block effects and errors from over-fitting. Simulation experiments show that our proposed CS based WZ codec associated with MAAR based SI generation achieves better results compared to other SI extrapolation methods.

• 대한환경공학회지
• /
• 제37권8호
• /
• pp.450-457
• /
• 2015

본 연구에서는 제올라이트를 PVA에 고정화시켜 새로운 흡착제인 PVA-Zeolite 비드를 제조하고, XRD 및 SEM 분석을 통해 제조한 PVA-Zeolite 비드는 내부에 제올라이트가 잘 고정화된 다공성 구조를 가지고 있는 것을 확인할 수 있었다. 제조한 흡착제에 의한 Cs 이온과 Sr 이온에 대한 흡착특성을 살펴보기 위하여 pH의 영향, 흡착속도, 흡착등온을 검토하였다. Sr 및 Cs 이온에 대한 평형흡착시간은 약 540 min으로 나타났으며, 흡착속도는 유사 1차 속도식 보다는 유사 2차 속도식에 더 잘 부합하였다. 흡착평형 실험결과는 Langmuir 등온식에 잘 적용되었으며, Langmuir 등온식으로부터 구한 Sr 이온과 Cs 이온의 최대 흡착량은 각각 52.08 mg/g와 58.14 mg/g이었다. PVA-Zeolite 비드에 의한 Sr 이온과 Cs 이온의 흡착공정은 외부물질전달단계는 매우 빠르게 이루어지며, 내부입자확산에 의한 흡착반응은 느리게 진행되어 내부입자확산 단계가 흡착속도 결정단계인 것으로 판단된다.

• 한국환경과학회지
• /
• 제28권6호
• /
• pp.561-570
• /
• 2019

A zeolitic material (Z-Y2) was synthesized from Coal Fly Ash (CFA) using a fusion/hydrothermal method under low-alkali condition (NaOH/CFA = 0.6). The adsorption performance of the prepared zeolite was evaluated by monitoring its removal efficiencies for Sr and Cs ions, which are well-known as significant radionuclides in liquid radioactive waste. The XRD (X-ray diffraction) patterns of the synthesized Z-Y2 indicated that a Na-A type zeolite was formed from raw coal fly ash. The SEM (scanning electron microscope) images also showed that a cubic crystal structure of size $1{\sim}3{\mu}m$ was formed on its surface. In the adsorption kinetic analysis, the adsorption of Sr and Cs ions on Z-Y2 fitted the pseudo-second-order kinetic model well, instead of the pseudo-first-order kinetic model. The second-order kinetic rate constant ($k_2$) was determined to be $0.0614g/mmol{\cdot}min$ for Sr and $1.8172g/mmol{\cdot}min$ for Cs. The adsorption equilibria of Sr and Cs ions on Z-Y2 were fitted successfully by Langmuir model. The maximum adsorption capacity ($q_m$) of Sr and Cs was calculated as 1.6846 mmol/g and 1.2055 mmol/g, respectively. The maximum desorption capacity ($q_{dm}$) of the Na ions estimated via the Langmuir desorption model was 2.4196 mmol/g for Sr and 2.1870 mmol/g for Cs. The molar ratio of the desorption/adsorption capacity ($q_{dm}/q_m$) was determined to be 1.44 for Na/Sr and 1.81 for Na/Cs, indicating that the amounts of desorbed Na ions and adsorbed Sr and Cs ions did not yield an equimolar ratio when using Z-Y2.

• 청정기술
• /
• 제23권4호
• /
• pp.413-420
• /
• 2017

화력발전소에서 발생되는 석탄비산재로부터 합성한 제올라이트 X를 이용한 Cs 흡착의 회분식 실험 및 반응표면분석법(Response Surface Methodology, RSM)을 적용하여 결과를 분석하였다. Cs 흡착 실험에 적용된 회귀 방정식은 반응변수의 함수로 나타낼 수 있었다. 결정계수($r^2$)가 0.9630으로서 이 모델은 높은 상관성을 가졌다. pH > Cs 농도 > 온도와 같은 실험적 요인의 순서로 Cs의 제거효율에 영향을 준다는 것을 통계적인 결과로부터 확인하였다. 흡착속도는 유사 2차 모델에 의해 보다 정확하게 표현되었다. Langmuir 등온선 모델로부터 계산된 최대 흡착용량은 293 K에서 $151.52mg\;g^{-1}$이었다. 또한, Vant Hoff 식에 의해 계산된 열역학 파라미터에 의거하여 흡착반응이 흡열반응이며, 자발적인 과정임을 확인할 수 있었다.