• Transactions of the Korean Society of Automotive Engineers
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• v.10 no.2
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• pp.193-200
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• 2002

Simple spring-damper-mass models have been widely used to investigate whole-body vortical biodynamic response characteristics of the seated vehicle driver. Most previous models have not considered the effect of wobbling masses; i.e. heart, lungs, liver, intestine, etc. In this study, 4 -DOF seated driver model including one non-rigid mass representing wobbling visceral mass, 5-DOF model including intestine, and 10-DOF model including five lumbar vertebral masses were proposed. The model parameters were identified by a combinatorial optimization technique. simulated annealing method. The objective function was chosen as the sum of error between model response of seat-to-head transmissibility and driving point mechanical impedance and those of experimental data for subjects seated erect without backrest support. The model response showed a good agreement with the experimental response characteristics. Using a 10-DOF model, calculated resonance frequency of lumbar spine at 4Hz was matched well with experimental results of Panjabi et al.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.9
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• pp.1733-1740
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• 2011

In this research, a MEMS vibratory gyroscope with dual-mass system in the sensing mode has been proposed to increase the stability of the device using wide bandwidth. A wide flat region between the two resonance peaks of the dual-mass system removes the need for a frequency matching typically required for single mass vibratory gyroscopes. Bandwidth, mass ratio, spring constant, and frequency response of the dual-mass system have been analyzed with MATLAB and ANSYS simulation. Designed first and second peaks of sensing mode are 5,917 and 8,210Hz, respectively. Driving mode resonance frequency of 7,180Hz was located in the flat region between the two resonance peaks of the sensing mode. The device is fabricated with anodically bonded silicon-on-glass substrate. The chip size is 6mm x 6mm and the thickness of the silicon device layer is $50{\mu}m$. Despite the driving mode resonance frequency decrease of 2.8kHz and frequency shift of 176Hz from the sensing mode due to fabrication imperfections, measured driving frequency was located within the bandwidth of sensing part, which validates the utilized dual-mass concept. Measured bandwidth was 768Hz. Sensitivity calculated with measured displacement of driving and sensing parts was 22.4aF/deg/sec. Measured slope of the sensing point was 0.008dB/Hz.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.03a
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• pp.1466-1472
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• 2010

In order to construct extremely large scale of sea dike like Saemanguem dike, extremely large amount of mass of rock are needed. In this case, it is general methods to estimate required amount of rock mass based on characteristics of consolidation settlement and bearing capacity of seabed, because it is impossible to estimate exact amount of rock material based on varied seabed condition.. Even in this general methods, it is very few case to manage rock mass amount by estimation of actual input rock mass but the main point is focused on the final section formation considering of designed section and reserve embankment, so excessive or underestimating result of rock mass would be occurred surely. This general methods is not resonable in the points of economic and stable. In this study, optimum construction management method of rubble mound in the 3rd section construction of Saemanguem sea dike is suggested based on comparing required rock mass estimating from consolidation settlement theory with actual input rock mass. It is found out that the optimum input quantity of rock mass is about $1,900{\sim}2,000m^3$/day.

• Journal of Electrochemical Science and Technology
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• v.8 no.3
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• pp.244-249
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• 2017

This paper presents the results of an investigation into the isoamperic point of cyclic voltammograms, which is defined as the singular point where the voltammograms of various scan rates converge. The origin of the unique point is first considered from a theoretical perspective by formulating the voltammetric curves as a system of linear equations, the solution of which indicates that a trivial solution is only available at the potential at which the net current is zero during the reverse potential scan. In addition, by way of a mathematical formulation, it was also shown that the isoamperic point is dependent on the switching potential of the potential scanning. To validate these findings, theoretical and practical cyclic voltammmograms were studied using finite-element based digital simulations and 3-electrode cell experiments. The new understanding of the nature of the isoamperic point provides an opportunity to measure the charge transfer effects without the influence of the mass transfer effects when determining the thermodynamic and kinetic characteristics of a faradaic system.

• Journal of Korean Neurosurgical Society
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• v.49 no.6
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• pp.351-354
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• 2011

Objective : This investigation was conducted to evaluate a new, safe entry point for the C2 pedicle screw, determined using the anatomical landmarks of the C2 lateral mass, the lamina, and the isthmus of the pars interarticularis. Methods : Fifteen patients underwent bilateral C1 lateral mass-C2 pedicle screw fixation, combined with posterior wiring. The C2 pedicle screw was inserted at the entry point determined using the following method : 4 mm lateral to and 4 mm inferior to the transitional point (from the superior end line of the lamina to the isthmus of the pars interarticularis). After a small hole was made with a high-speed drill, the taper was inserted with a 30 degree convergence in the cephalad direction. Other surgical procedures were performed according to Harm's description. Preoperatively, careful evaluation was performed with a cervical X-ray for C1-C2 alignment, magnetic resonance imaging for spinal cord and ligamentous structures, and a contrast-enhanced 3-dimensional computed tomogram (3-D CT) for bony anatomy and the course of the vertebral artery. A 3-D CT was checked postoperatively to evaluate screw placement Results : Bone fusion was achieved in all 15 patients (100%) without screw violation into the spinal canal, vertebral artery injury, or hardware failure. Occipital neuralgia developed in one patient, but this subsided after a C2 ganglion block. Conclusion : C2 transpedicular screw fixation can be easily and safely performed using the entry point of the present study. However, careful preoperative radiographic evaluation, regardless of methods, is mandatory.

• Journal of The Korean Society of Agricultural Engineers
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• v.62 no.4
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• pp.13-22
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• 2020

The Doam Lake watershed has a significant impact on the downstream water system due to nutrients and sediment outflow during rainfall caused by steep slopes, soil losses, and fertilization. These non-point sources are unclear in the discharge area and are affected by land use patterns, soil characteristics, and topographical features of the watershed. Therefore, this study conducted rainfall monitoring from July to October 2019 in Songcheon upstream of the Doam Lake watershed, one of the non-point pollution source management areas. Then, after analyzing rainfall runoff, Event Mean Concentration (EMC) and Mass First Flush ratio (MFFn) were calculated to compare and analyze the characteristics of rainfall and the non-point pollutant discharge. As a result of the analysis, it showed various non-point pollutant emission characteristics for each rainfall event. In addition, the concentration of EMC and the MFFn were affected by the average rainfall intensity and the maximum rainfall intensity, and were not significantly affected by the number of antecedent drying days. In the future, it is expected that effective non-point source reduction measures and management measures according to rainfall intensity through continuous monitoring and analysis will be needed.

• Clinical and Experimental Pediatrics
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• v.61 no.1
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• pp.6-11
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• 2018

Purpose: Mid-upper-arm circumference (MUAC) is considered an alternative screening method for obesity. The aims of this investigation were to examine the ability of MUAC to correctly identify children with elevated body mass index (BMI) and to determine the best MUAC cutoff point for identification of children with high BMI. Methods: Anthropometric measurements (height, weight, and MUAC) from a cross-sectional sample of 7,921 Pakistani children aged 5-14 years were analyzed. Pearson correlation coefficients between MUAC and other anthropometric measurements were calculated. Receiver operating characteristic curve analysis was used to determine the optimal MUAC cutoff point for identifying children with high BMI. Results: Among 7,921 children, the mean (${\pm}$standard deviation) age, BMI, and MUAC were 10.00 (${\pm}2.86years$), 16.16 (${\pm}2.66kg/m^2$), and 17.73 (${\pm}2.59cm$), respectively. The MUAC had a strong positive correlation with BMI. The optimal MUAC cutoff points indicating elevated BMI in boys ranged from 16.76 to 22.73, while the corresponding values in girls ranged from 16.38 to 20.57. Conclusion: MUAC may be used as a simple indicator of overweight/obesity in children, with reasonable accuracy in clinical settings.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.38 no.2
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• pp.172-178
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• 2002

This study presents a dynamic simulation of a purse seine net behavior Mathematical model suitable for purse seining, which is based on data from a series of previous simulations, various field experiments, is modelized as a set of mass-spring system. In this model, a number of meshes are approximated as one mass point, each of which connected to its neighbors by massless springs, the equations of motion are derived from considering internal force from the springs and external forces such as resistance and gravitation. This simulation shows the quantitative state on every mass point of the net and purse line during the shooting and pursing phases. So it is possible that performance of a purse seine net be analyzed using various and evolving parameters such as the shooting speed, the hauling speed, the size or type of the sinker, float and twine, also the hanging ratio etc.

• Mass Spectrometry Letters
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• v.2 no.3
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• pp.61-64
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• 2011

Matrix Assisted Laser Desorption/Ionization-Time-of-Flight mass spectrometry (MALDI-TOF-MS) is the most widely used MS technique for glycan analysis. However, the poor point-to-point and sample-to-sample reproducibility becomes a limit in glycan biomarker research. A prespotted MALDI plate which overcomes the large crystal formation of 2,5-dihydroxybenzoic acid (DHB) has been developed and applied for glycan analysis. A homogeneous matrix coated surface without a crystal structure was formed on a hydrophilic/ hydrophobic patterned surface using a piezoelectric device. The reproducible MALDI-TOF-MS data have been presented using MALDI imaging of beer glycan as well as serum glycan eluted from 10% and 20% ACN elution fractions. The glycan profile from the serum glycan by MALDI-TOF-MS with a DHB prespotted plate was highly conserved for 10 different spectra and the coefficient of variations of significant ion peaks of MALDI data varies from 3.59 to 19.95.

• Structural Engineering and Mechanics
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• v.54 no.1
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• pp.55-67
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• 2015

Taking the mid-span/center-point of the structure as the reference point of capturing the maximum dynamic response is very customary in the available literature of the moving load problems. In this article, the absolute maximum dynamic response of an Euler-Bernoulli beam subjected to a moving mass is widely investigated for various boundary conditions of the base beam. The response of the beam is obtained by utilizing a robust numerical method so-called OPSEM (Orthonormal Polynomial Series Expansion Method). It is underlined that the absolute maximum dynamic response of the beam does not necessarily take place at the mid-span of the beam and thus the conventional analysis needs modifications. Therefore, a comprehensive parametric survey of the base beam absolute maximum dynamic response is represented in which the contribution of the velocity and weight of the moving inertial objects are scrutinized and compared to the conventional version (maximum at mid-span).