• Journal of Korean Society of Transportation
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• v.34 no.6
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• pp.499-509
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• 2016

The pedestrian traffic flow has more complicated microscopic features than vehicular traffic flow. Without any designated lanes or any guidance, pedestrians naturally move and change their routes in two dimensional domain with ease. Thus the assessment of pedestrian comfort level should be considering the microscopic features of pedestrian flow. This study is aimed at developing pedestrian comfort criteria based upon pedestrian flow simulation model. This study suggests three criteria to determine pedestrian comfort level; the deviation of route, the acceleration of walk, and the number of collision. Each criterion, which can address the unique walking patterns of pedestrian flow, is represented as each different function with respect to traffic flow rate. The criteria can be the additional indicators to determine the level of service of pedestrian flow together with traffic flow rate and walking speed.

• Proceedings of the KOSOMBE Conference
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• v.1997 no.05
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• pp.150-155
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• 1997

Modelling and Simulation of the activation process for the myocardium is meaningful to understand special excitation conduction system in the heart and to study cardiac functions. In this paper, we propose two dimensional cellular automata model for the activation process of the myocardium and simulated by means of discrete time and discrete event algorithm. In the model, cells are classified into anatomically similar characteristic parts of heart; SA node, internodal tracks, AV node, His bundle, bundle branch and four layers of the ventricular muscle, each of which has a set of cells with preassigned properties, that is, activation time, refractory duration and conduction time between neighbor cell. Each cell in this model has state variables to represent the state of the cell and has some simple state transition rules to change values of state variables executed by state transition function. Simulation results are as follows. First, simulation of the normal and abnormal activation process for the myocardium has been done with discrete time and discrete event formalism. Next, we show that the simulation results of discrete time and discrete event cell space model is the same. Finally, we compare the simulation time of discrete event myocardium model with discrete time myocardium models and show that the discrete event myocardium model spends much less simulation time than discrete time myocardium model and conclude the discrete event simulation method Is excellent in the simulation time aspect if the interval deviation of event time is large.

• The Bulletin of The Korean Astronomical Society
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• v.39 no.2
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• pp.57.2-57.2
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• 2014

Red active galactic nuclei (AGNs) are supposed to be transitional objects becoming normal AGNs in the galaxy evolution scenario. So far, ~200 red AGNs have been found by very red color in optical through NIR wavelength (e.g., r'-K >5 and J-K>1.3; Urrutia et al. 2009). Here, we compare nuclear activities of the red AGNs to those of normal AGNs to verify the evolutionary phase of the red AGNs. In order to study the nuclear activities of the red AGNs, we use broad emission lines of $P{\beta}$ ($1.28{\mu}m$) of which flux is less suppressed by a factor of 100 than the $H{\beta}$ line in the case of the red AGNs with a color excess of E(B-V)=2 mag. We use 16 red AGNs discovered in previous red AGN surveys by using SDSS, 2MASS, and FIRST (Glikman et al. 2007; Urrutia et al. 2009) at z ~0.7 for which $P{\beta}$ lines are redshifted to the sky window at ${\sim}2.2{\mu}m$. The mean Eddington ratio of the 16 red AGNs is 0.562, and that of the normal AGNs is 0.320, which indicates the red AGNs include more active black hole (BH) than the normal AGNs. To test how significantly the nuclear activities of the red AGNs and the normal AGNs are different, we perform a two-dimensional Kolmogorov-Smirnov test (K-S test) on their Eddington ratio distributions. The K-S test shows the maximum deviation between the cumulative distributions, D, is 0.48, and the probability of null hypothesis, p, is even less than 0.001. This result is consistent with a picture of that the red AGNs are in intermediate phase between the stage of merger-driven starburst galaxy and the normal AGN.

• Journal of the Korean Society of Propulsion Engineers
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• v.24 no.2
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• pp.28-34
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• 2020

In order to relieve the burden of the rear ablative material, the combustion test of the solid rocket motor with the forward deployed multi-pin grain design was successfully performed twice. However, after disassembling the solid rocket motor, a non-uniform ablation pattern was found in the rear ablative material. Periodic repetition of local and regional ablation was measured precisely. Two-dimensional flow and eddy flow, created by the uneven main-pin flow hitting the rear ablative material, were identified as the cause of non-uniform ablation. In addition. when the rear pins were removed, the possibility of securing the soundness of the rear ablative material was confirmed as the average flow velocity and the standard deviation were lowered.

• Journal of Hydrogen and New Energy
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• v.21 no.1
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• pp.1-11
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• 2010

Current distribution measurement technique based on a segmented bipolar plate (BP) has been widely adopted to visualize the distribution of current density in a polymer electrolyte membrane. However, a concern is raised how closely the current density of a segmented BP can approach that of a corresponding non-segmented membrane. Therefore, in this paper, the accuracy of the measurement technique is numerically evaluated by applying a three-dimensional, two-phase fuel cell model to a $100\;cm^2$ area fuel cell geometry in which segmented BPs and non-segmented membrane are combined together. The simulation results reveal that the errors between the current densities of the segmented BPs and non-segmented membrane indeed exist, predicting the maximum relative error of 33% near the U-turn regions of the flow-field. The numerical study further illustrates that the erroneous result originates from the BPs segmented non-symmetrically based on the flow channels that allows some currents bypassing flow channels to flow into its neighboring segment. Finally, this paper suggests the optimal way for bipolar plate segmentation that can minimize the deviation of current measured in a segmented BP from that of a corresponding membrane region.

• Journal of Korean Society for Quality Management
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• v.48 no.2
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• pp.269-282
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• 2020

Purpose: The practical design for experiments with mixtures of q components is consisted in the four types of design points, vertex, center of edge, axial, and center points in a (q-1)-dimensional simplex space. We propose a sequential method for the successful construction of the design space in Quality by Design (QbD) by allowing the different number of replicates at the four types of design points in the practical design when the quadratic canonical polynomial model is assumed. Methods: To compare the mixture designs efficiency, fraction of design space (FDS) plot is used. We search for the practical mixture designs whose the minimal half-width of the tolerance interval per a standard deviation, which is denoted as d₂, is less than 4.5 at 0.8 fraction of the design space. They are found by adding the different number of replicates at the four types of the design points in the practical design. Results: The practical efficient mixture designs for the number of components between three and five are listed. The sequential method to establish a design space is illustrated with the two examples based on the simulated data. Conclusion: The designs with the center of edge points replications are more efficient than those with the vertex points replication. We propose the sample size of at least 23 for three components, 28 for four components, and 33 for the five components based on the list of efficient mixture designs.

• Bulletin of the Korean Chemical Society
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• v.31 no.11
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• pp.3333-3340
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• 2010

A three dimensional pharmacophore model was generated for the molecules which are responsible for anti-inflammatory activities targeting Interleukin-2 inducible tyrosine kinase (Itk). 16 structurally diverse molecules were selected as training set to generate the hypotheses using Discovery Studio v2.1. The best hypothesis, Hypo1, comprises two hydrogen bond acceptor (HBA), one hydrophobic aromatic (HA), one ring aromatic (RA) and shows high cost difference (63.71), high correlation coefficient (0.97) as well as low RMS deviation (0.81). Hypo1 has been further validated toward a test set, decoy set and Fischer's randomization method. Furthermore, Hypo1 was used to screen NCI and Maybridge databases. Finally, 2 hit molecules were identified as potential leads against Itk, which may be useful for future drug development.

• Nuclear Engineering and Technology
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• v.15 no.4
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• pp.267-279
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• 1983

An analytical system has been established for scrutinizing both uranium- and plutonium-fueled lattices moderated by light water. This system consists of two primary codes. One is a unit cell program called KICC, which has theoretical foundation on the models of GAM and THERMOS incorporated with appropriate approximate treatments for various phenomena, whereas the other is a multi-dimensional diffusion-depletion program entitled KIDD. The adequacy of this system is verified by performing extensive benchmark calculations on a variety of critical experiments. The average value of effective multiplication factors for the selected nineteen UO$_2$ critical experiments of heterogeneous lattice structure is calculated to be 1.0006 with a standard deviation of 0.0039. Power distributions have also been calculated for some critical experiments fueled with both uranium and plutonium of varying concentrations. The maximum percentage difference between the measured and calculated power distributions appears to be less than 5%. This result, together with the previously reported result, illustrates that the KICC/KIDD system is a very effective tool for the analysis of a light water reactor core.

• Korean Journal of Optics and Photonics
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• v.16 no.4
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• pp.361-365
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• 2005

An absolute interferometer system with multiple point-sources is devised for tile 3-D measurement of rough surface profiles. The positions of the point sources are determined to be the system parameters that influence the measurement accuracy, so they are calibrated precisely prior to performing actual measurements. For the calibration, a CCD camera composed of a two-dimensional array of photo-detectors was used. Performing optimization of the cost function constructed with phase values measured at each pixel on the CCD camera, the position coordinates of each point source is precisely determined. Measurement results after calibration performed for the warpage inspection of chip scale packages (CSPs) demonstrate that the maximum discrepancy is 9.8 mm with a standard deviation o( 1.5 mm in comparison with the test results obtained by using a Form Taly Surf instrument.

• Journal of the Korea Computer Industry Society
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• v.6 no.3
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• pp.495-508
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• 2005

Moving objects are spatiotemporal data that change their location or shape continuously over time. Their location coordinates are periodically measured and stored i3l the application systems. The linear function is mainly used to estimate the location information that is not in the system at the query time point. However, a new method is needed to improve uncertainties of the location representation, because the location estimation by linear function induces the estimation error. This paper proposes an application method of the cubic spline interpolation in order to reduce deviation of the location estimation by linear function. First, we define location information of the moving object on the two-dimensional space. Next, we apply the cubic spline interpolation to location estimation of the proposed data model and describe algorithm of the estimation operation. Finally, the precision of this estimation operation model is experimented. The experimentation comes out more accurate results than the method by linear function.