• Transactions of the Korean Society of Automotive Engineers
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• v.9 no.1
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• pp.8-19
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• 2001

A number of atomization and droplet breakup models have been developed and used to predict the diesel spray characteristic. Most of these models could not provide reasonable computational result of the diesel spray characteristic because they have only considered the primary breakup. A hybrid model is, therefore, required to develop by considering the primary and secondary breakup of liquid jet. according to this approach, wave breakup(WB) model was used compute the primary breakup of the liquid jet and droplet deformation and breakup(DDB) model was used for the secondary breakup of droplet. Development of hybrid model by using KIVA-II code was performed by comparing with the experimental data of spray tip penetration and SMD from the literature. A hybrid model developed in this study could provide the good agreement with the experimental data of spray tip penetration. The prediction results of SMD were in good agreement between 0.5 and 1.0 ms after the start of injection. Numerical results obtained by the present hybrid model have the good agreement with the experimental data with the breakup time constant in WB model of 30, and DDB model constant Ck of 1.0 when the droplet becomes less than 95% of maximum droplet diameter injected.

• Journal of the Korean Institute of Intelligent Systems
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• v.15 no.2
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• pp.251-256
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• 2005

Up to now, a number of models have been proposed and discussed to describe a wide range of inelastic behaviors of materials. The fetal problem of using such models is however the existence of model errors, and the problem remains inevitably as far as a material model is written explicitly. In this paper, the authors define the implicit constitutive model and propose an implicit viscoplastic constitutive model using neural networks. In their modeling, inelastic material behaviors are generalized in a state space representation and the state space form is constructed by a neural network using input output data sets. A technique to extract the input-output data from experimental data is also described. The proposed model was first generated from pseudo-experimental data created by one of the widely used constitutive models and was found to replace the model well. Then, having been tested with the actual experimental data, the proposed model resulted in a negligible amount of model errors indicating its superiority to all the existing explicit models in accuracy.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.239-239
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• 2000

This paper present experimental results on temperature trajectory tracking. The benefits of precalculated feedforward input together with PID feedback control are demonstrated by experimental results. To find the feedforward input, the plant (autoregresiive) model is first identified and convex optimization procedure is applied. PID controller is then implemented based on Ziegler-Nickels tuning rule to reduce effects of disturbances and modeling errors. Experimental results show an improvement in slope tracking performance over the fully PID controller.

• Toxicological Research
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• v.17
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• pp.293-297
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• 2001

The international pharmaceutical and regulatory communities had been recognizing the limited utility of conventional rodent carcinogenicity study particularly on the second species, mouse, after intense investigation of carcinogenicity data base worldwide, and a new scheme for carcinogenicity testing for pharmaceuticals was proposed at the Expert Working Group on Safety in the International Conference on Harmonization (ICH) in 1996. CB6F 1-Tg rasH2 mouse carrying human prototype c-Ha-ras gene with its own promoter/enhancer is one oj the new carcinogenicity assay model for human cancer risk assessment. Studies have been conducted since 1992 to validate the transgenic (Tg) mice for rapid carcinogenicity test-ing, short term (26 weeks) studies with genotoxic (by Salmonella), non-genotoxic carcinogens, genotoxic non-carcinogens, non-genotoxic non-carcinogens revealed relatively high concordance oj the response of the Tg mouse with classical bioassay across classes of carcinogenic agents. Mechanistic basis for carcinogensis in the model are being elucidated in terms of the role of overexpression and/or point mutation of the transgene. This report review the initial studies of validation of the model and preliminary results of on-going ILSI HESI ACT project will be presented.

• Coupled systems mechanics
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• v.12 no.5
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• pp.419-428
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• 2023

We have developed a model for estimating the parameters of viscous materials from indirect tensile tests for asphalt. This is a simple Burger nonlinear rheological two-cell model or standard model. At the same time, we begin to develop a more versatile and complex multi-cell model. The simple model is validated using experimental load-displacement results from laboratory tests: The recorded displacements are used as input values and the measured force data are simulated with the model. The optimal model parameters are estimated using the Levenberg-Marquardt method and a very good agreement between the experimental results and the model calculations is shown. However, not all parts of the model are active in the loading phase of the experiment, so we extended the validation of the model to the simulation of the relaxation behaviour. In this stage, the other model parameters are activated and the simulation results are consistent with the literature. At this stage, we have estimated the parameters only for the two-cell uniaxial model, but further work will include results for the multi-cell model.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.20 no.2 s.33
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• pp.142-150
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• 2007

Objectives : This study was carried out to investigate the latest study tendency in mouse model of skin pruritus published since 2005 and to arrange various experimental methods. Methods : We examined the journal(such as Experimental dermatology and British journal of dermatology) and in Pubmed since 2005, regarded pruritus and scratching behavior model as key words. Results and Conclusion : 1. BALB/c, hairless, NC/Nga and ICR mice were the most used in scratching behavior model. According to scratching-induced agents. we need to select experimental mice. 2. There are various methods inducing skin pruritus; by cohabitation with NC/Nga mice having severe skin lesions, by injection intradermally(or subcutaneously) with agent inducing inflammation, by inducing contact dermatitis with TNCB, TNFB, destruction of skin barrier and by transgenic mice. 3. Injection intradermally(or subcutaneously) with agent inducing inflammation is the most used out of methods inducing skin pruritus. Compound 48/80, histamine, substance P and others(chloroquine, serotonin, carrageenin, TPA etc.) were included in agents inducing inflammation and pruritus in skin pruritus model. 4. Video camera, SCLABA system, MicroAct and acoustic evaluation system were included in evaluation methods of scratching behavior mouse model.

• Journal of the Korean Solar Energy Society
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• v.33 no.3
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• pp.17-26
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• 2013

The aim of this study is to analyze the performance of a parabolic trough solar collector (PTC) for water heating and to validate the model performance. The simulated model was compared, calibrated and verified with the experimental results. RMSE (Root mean square error) was used to calibrate the convective heat transfer coefficient between the absorber pipe and the ambient air which was the main factor affecting the heat transfer associated with the PTC. The calibrated model was better fitted with the experimental model. The maximum, minimum and mean deviation between the measured and predicted water temperatures differed only $0.81^{\circ}C$, $0.09^{\circ}C$ and $0.31^{\circ}C$ respectively in the calibrated model. RMSE values were decreased from 0.5389 to 0.4910, 0.0134 to 0.0125 and R-squared was increased from 0.9955 to 0.9956 after calibration. The temperature of water was increased from $33.7^{\circ}C$ to $48^{\circ}C$ in 12hour test. The thermal efficiency of the collector was calculated to be 55%. The calibrated model showed good agreement with the experimental data for model validation.

• Computers and Concrete
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• v.20 no.6
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• pp.711-718
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• 2017

Nanotechnology is a new filed in concrete structures which can improve the mechanical properties of them in confronting to impact and blast. However, in this paper, a mathematical model is introduced for the concrete models subjected to impact load for wave propagation analysis. The structure is simulated by the sinusoidal shear deformation theory (SSDT) and the governing equations of the concrete model are derived by energy method and Hamilton's principle. The silicon dioxide ($SiO_2$) nanoparticles are used as reinforcement for the concrete model where the characteristics of the equivalent composite are determined using Mori-Tanaka approach. An exact solution is applied for obtaining the maximum velocity of the model. In order to validate the theoretical results, three square models with different impact point and Geophone situations are tested experimentally. The effect of different parameters such as $SiO_2$ nanoparticles volume percent, situation of the impact, length, width and thickness of the model as well as velocity, diameter and height of impactor are shown on the maximum velocity of the model. Results indicate that the theoretical and experimental dates are in a close agreement with each other. In addition, using from $SiO_2$ nanoparticles leads to increase in the stiffness and consequently maximum velocity of the model.

• Steel and Composite Structures
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• v.49 no.1
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• pp.1-17
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• 2023

Based on Ahmadzadeh-Varvani hardening rule (A-V model), multiaxial ratcheting effect of Z2CND18.12N austenitic stainless steel is simulated by ABAQUS with user subroutine UMAT. The results show that the predicted results of the origin multiaxial A-V model are lower than the experimental data, and it is difficult to control ratcheting strain rate. In order to improve the predicted capability of A-V model, the A-V model is modified. In this study. Moreover, under the assumption of the von Mises yield criterion and normal plasticity flow rule, we develop a numerical algorithm of plastic strain with the improved model to implement the finite element calculation of the model. Internal iteration in the numerical algorithm was implemented with the Euler backward method, which calculated the trial strain for each equilibrium iteration using the consistent tangent matrix. With a user subroutine, the proposed model is programmed into ABAQUS for a user - executable version. By simulating the uniaxial ratcheting of a round bar made of Z2CND18.12N austenitic stainless steel, we observe that the predicted results simulated by ABAQUS with UMAT are compared with the experimental data. The predicted results of the improved multiaxial A-V model are consistent well with the experimental data.

• Journal of the Korean Society of Clothing and Textiles
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• v.24 no.1
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• pp.105-115
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• 2000

This study was intended to find body pattern of middle aged women and make new experimental basic pattern for upper-half of the body for them. This experimental pattern on the idea of body pattern analysis was prepared. For experimental pattern, the prototype basic model was chosen with the best qualified D model from the four meaningful existing patterns. After several steps of correction experimental pattern was made. Comparing with basic D model, the new experimental pattern composed of additional bust girth by 1cm, wider back waist by 0.5cm than front waist and additional armhole by 0.5cm keeping the same size for back and front widths. Making a shoulder line up by 3cm the armhole became deeper accordingly and the room for girth has been transferred to length. Front neck girth became deeper downward but back neck girth risen a little bit. Side line of the bodice formed with inward slope taking from the waist line by 2cm. Instead of dart, modified side line slope was more practical by its function and appearance. Abdominal girth which is lower than waist girth by 8.5cm kept in same size with bust girth. Then abdominal girth became more comfortable. New experimental pattern with changes has been examined in function and appearance. In conclusion, the new experimental basic pattern for the middle-aged women has been proved more practical for both in bodice and sleeve than other existing ones in terms of function and appearance.