• Journal of Korean Society of Water and Wastewater
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• v.29 no.3
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• pp.427-436
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• 2015

Developing two process models to simulate wastewater treatment process is needed to draw a comparison between measured BOD data and estimated process model data: a mathematical model based on the process mass-balance and an ANN (artificial neural network) model. Those two types of simulator can fit well in terms of effluent BOD data, which models are formulated based on the distinctive five parameters: influent flow rate, effluent flow rate, influent BOD concentration, biomass concentration, and returned sludge percentage. The structuralized mass-balance model and ANN modeI with seasonal periods can estimate data set more precisely, and changing optimization algorithm for the penalty could be a useful option to tune up the process behavior estimations. An complex model such as ANN model coupled with mass-balance equation will be required to simulate process dynamics more accurately.

• Communications for Statistical Applications and Methods
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• v.18 no.2
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• pp.229-236
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• 2011

A continuous time stochastic volatility model for financial assets suggested by Barndorff-Nielsen and Shephard (2001) is considered, where the volatility process is modelled as an Ornstein-Uhlenbeck type process driven by a general L$\'{e}$vy process and the price process is then obtained by using an independent Brownian motion as the driving noise. The uniform ergodicity of the volatility process and exponential ${\alpha}$-mixing properties of the log price processes of given continuous time stochastic volatility models are obtained.

• Journal of the Korean Society of Industry Convergence
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• v.23 no.6_2
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• pp.1103-1110
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• 2020

In this study, a segmented model with Upside-Down bathtub shaped failure intensity for a repairable system are proposed under the assumption that the occurrences of the failures of a repairable system follow the Non-Homogeneous Poisson Process. The proposed segmented model is the compound model of S-PLP and LIP (Segmented Power Law Process and Logistic Intensity Process), that fits the separate failure intensity functions on each segment of time interval. The maximum likelihood estimation is used for estimating the parameters of the S-PLP and LIP model. The case study of system A shows that the S-PLP and LIP model fits better than the other models when compared by AICc (Akaike Information Criterion corrected) and MSE (Mean Squared Error). And it also implies that the S-PLP and LIP model can be useful for explaining the failure intensities of similar systems.

• 한국연소학회:학술대회논문집
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• 2014.11a
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• pp.165-166
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• 2014

The application of particle reaction model in the packed bed process modeling is discussed for iron ore pellet induration process. Combustion of coke breeze in the pellet is estimated by using shrinking unreacted-core model and grain model in which the progress of chemical reaction is described in different concepts. Under the identical inlet gas and solid conditions, the calculation using shrinking core model showed deviated results in terms of temperature profile and conversion fraction, which may imply the significance of selecting proper particle reaction model in consideration of particle characteristics and process operation conditions.

• Journal of Biomedical Engineering Research
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• v.13 no.2
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• pp.97-106
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• 1992

The cardiac activation process uslng three dimensional ventricular model is simulated. To study this theme, we constructed a cardiac ventricular model and simulated the cardiac activation process using the action potential duration and the activation time. The cardiac ventricular model is generated by the loglcal combination of the elliptic equations. The action potential duration could be obtained from the fact that It Is linearly distributed between model cells. The cardiac activation process was simulated by the law of "all-or-none". Based on the activation time and the action potential duration the cardiac potential at the arbitrary time after the activation of the model cell was computed. To test the validity of model, the comparison of the results of model simulation with the physiological data was performed. In conclusion, this model shows the simular results which is comparable to the 1 Pal conduction of the cardlac excitation.xcitation.

• Journal of Korean Institute of Industrial Engineers
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• v.26 no.3
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• pp.227-237
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• 2000

A workflow management system is a software system to assist designing processes, controlling and managing the execution of the designed processes. One emerging trend in many recent information systems is the provision of process management functions. In this paper, we propose a method of designing processes for automatic process execution directly from process modeling. First of all, the concept of block is presented which is to define a nested process model. A block is the minimum unit that can specify the relationships of process components, i.e., tasks. A general process can be defined by a combination of the blocks defined in this paper. An algorithm is developed to transform a general flat process model into a nested model. We identify basic types of blocks and build ECA (Event-Condition-Action) rules for each of the basic types. This allows us to automate the execution of the process model by using the active features of active databases.

• Archives of design research
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• v.20
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• pp.61-72
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• 1997

This study aims to promote understanding level for mathematical model, to improve methods and necessity of application in the process of product design and also to promote approaching and applying methods as a guideline for beginners. For the procedure and method of study first, it was emphasized by linking method and necessity of scientific analysis and a quality of product design and design process. Next, the corresponding relations between mathematical model and design probelem was desciebed, the mathematical model was examinated appeying process of product design. Lastly, approaching and applying methods for beginners was presented based on the discribed studied contents. As the result of the study, some points are by a result or problem : frist, the point that mathematical model is useful to grasp the design problems which various elements are complicately involved quantitatively and structurally, and its necessity can be especially utilized as a tool to justify and convince the convince the conclusion of the designer himself to the persons concerned. Second, the point that in order to apply mathematical model to the design process skillfully, first of all, the substance of all mathematical models which can be applid, and it is not easy to command in perfect method without using computer. Third, the point that since there are many kindsof mathematical models used is mathematical modeland the models which can be applidied to solve design problems differ in accordance with the design types and design process, its applying method can be presented as one kind of standardization or concretely. Fourth the point that in case of approaching mathematical model for the first time, it can start to select model corresponding with design type by stage of design process bassed on understanding for some mathematical knowledge and computer program.

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.3467-3472
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• 2007

The effects of the wall geometry on the spray-wall impingement process of a hollow-cone fuel spray emerging from a high-pressure swirl injector of the Gasoline Direct Injection (GDI) engine were investigated by means of a numerical method. The ized Instability Sheet Atomization (LISA) & Aerodynamically Progressed Taylor Analogy Breakup (APTAB) model for spray atomization process and the Gosman model were applied to model the atomization and wall impingement process of the spray. The calculation results of spray characteristics, such as a spray development process and a radial distance after wall impingement, compared with the experimental ones by the Laser Induced Exciplex Fluorescence (LIEF) technique. It was found that the radial distance of the cavity angle of 90$^{circ]$ after wall impingement was the shortest and the ring shaped vortex was generated near the wall after spray-wall impingement process.

• Korean Management Science Review
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• v.16 no.1
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• pp.75-85
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• 1999

In recent, an unfaithful construction bring about many social problems. The bidding process considering bidding price firstly is one of the reasons raising an unfaithfull construction work. Thus, we should consider many other criteria including bidding price in the bidder selection process. This paper suggests an analytic hierarchy process(AHP) model for selecting the best bidder of a large construction project. A questionnaire was used to obtain domain experts' opinion about criteria to be considered in the bidding process. A hierarchical structure of the AHP model is formed using criteria obtained in the survey. The model consists of bidding price, construction capability, financial status, faith, and their 17 sub-attributes. The relative importance of bidders are judged by pairwise comparison or absolute measurement. An illustrative example is given to show the process selecting the best bidder using the suggested AHP model.

• Management & Information Systems Review
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• v.31 no.4
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• pp.433-444
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• 2012

The purpose of this study is to develop the evaluation model of BPMS(business process management systems) based on AHP(analytical hierarchy process). In this study, we draw some criteria to select BPMS solution from a experts panel. And, we develop an evaluation model based on AHP method. As a result, each organization can select the effective BPMS solution from the proposed evaluation model.