• Korean Journal of Health Education and Promotion
• /
• v.24 no.4
• /
• pp.161-179
• /
• 2007

To commonly apply the ${\ulcorner}$Measurement parameter for housewives for rearing-related supports of a husband${\lrcorner}$ in Korea and Japan, the current study conducted to confirm the relationship between recognition of a housewife for rearing-related supports of a husband and mental health after reviewing the appropriateness of the parameter. For the statistical analysis, 829 married Korean women in D city and 1,302 Japanese women in S city having children before entering a school were subjected for the study. For reviewing the appropriateness of the parameter, the simultaneous factor analysis that adopted the structural equation modeling was used. As the result of the analysis, 10 categories of factor structural model comprising the ${\ulcorner}$Recognition of a housewife for rearing-related supports of a husband${\lrcorner}$ resulted with the secondary model which sets of ${\ulcorner}$Recognition for emotional support${\lrcorner}$, ${\ulcorner}$Recognition for instrumental support${\lrcorner}$ and ${\ulcorner}$Recognition for information support${\lrcorner}$ as the primary factor and ${\ulcorner}$Recognition of a housewife for rearing-related supports of a husband${\lrcorner}$ as the secondary factor, and the model was found to be appropriate for the data in Korea and Japan. The result is considered to prove the constructs validity of ${\ulcorner}$Recognition of a housewife for rearing-related supports of a husband${\lrcorner}$ parameter. In addition, the relationship between ${\ulcorner}$Recognition of a housewife for rearing-related supports of a husband${\lrcorner}$ and mental health(GHQ) was reviewed by using multiple indicator model, and found the similarity of Korean and Japanese data. The scores measured by using the above parameter resulted to show high relationship with educational level of housewife, family configuration, and number of children.

• Progress in Superconductivity
• /
• v.9 no.2
• /
• pp.146-151
• /
• 2008

Measurements of surface resistance ($R_s$) of high temperature superconductor (HTS) films with accuracy are essential for microwave applications of HTS materials. In using the dielectric resonator method, uncertainties in the unloaded quality factor of the resonator cause significant errors in the measured $R_s$ of HTS films. We compare the Rs values of $YBa_2Cu_3O_{7-{\delta}}$ films calculated from the $Q_0$ as determined from the Lorentzian fit with that from the $Q_0$ as determined from the S-parameter circle-fit at temperatures between 15 K and 77 K. The two sets of values appeared to differ by 5%, 7%, 6%, and 11% at temperatures of 15, 60, 70, and 77 K, respectively, from each other, implying that careful error analysis needs to be performed in obtaining the $R_s$ of HTS films by using the Lorentzian-fit method, with the ones determined from the S-parameter circle-fit used as the reference.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.28 no.10
• /
• pp.1541-1548
• /
• 2004

A nano-stage simulation tool is developed for an advanced E-beam lithography system. Even if piezo-actuators are believed to be compatible fer the E-beam lithograpy system it is difficult to predict their characteristics due to their nonlinearities such as hysteresis and creep. In this paper, the nonlinear properties are modeled for a piezo-actuator by considering the voltage range and speed variations. The hysteresis is described as the first order differential equation with 24 sets of parameters and the creep is modeled as a time-dependent logarithmic function with 2 sets of a parameter. A two-axis nano stage with piezo-actuators are investigated for realizing nano scale motions. The characteristics of flexure guide mechanisms are analyzed based on the finite element method using the ANSYS software. The simulation tool for the nano stage is constructed by using the RecurDyn software. The dynamic response of the nano stage is obtained in simulations and compared with the experimental data.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.15 no.4
• /
• pp.67-72
• /
• 2016

Planetary gear sets are widely used in power transmission components, which have high efficiency and good durability. Their most important design parameter is the load-sharing characteristics among several planetary gears. In this study, the load sharing of planetary gears was analyzed according to the carrier pinhole position error of planetary gear sets. The loads acting on planetary gears varied with the pinhole position error of the carrier, and the load sharing of planetary gears improved as the input load increased. In addition, the load of the planetary gear with a carrier pinhole position error was relatively higher than that of other planetary gears without carrier pinhole position errors. This trend appeared more clearly in the non-floating-type carrier than the floating-type carrier.

• Journal of Institute of Control, Robotics and Systems
• /
• v.11 no.4
• /
• pp.304-313
• /
• 2005

The robots that will be needed in the near future are human-friendly robots that are able to coexist with humans and support humans effectively. To realize this, robot need to recognize his position and direction for intelligent performance in an unknown environment. And the mobile robots may navigate by means of a number of monitoring systems such as the sonar-sensing system or the visual-sensing system. Notice that in the conventional fusion schemes, the measurement is dependent on the current data sets only. Therefore, more of sensors are required to measure a certain physical parameter or to improve the accuracy of the measurement. However, in this research, instead of adding more sensors to the system, the temporal sequence of the data sets are stored and utilized for the accurate measurement. As a general approach of sensor fusion, a UT -Based Sensor Fusion(UTSF) scheme using Unscented Transformation(UT) is proposed for either joint or disjoint data structure and applied to the landmark identification for mobile robot navigation. Theoretical basis is illustrated by examples and the effectiveness is proved through the simulations and experiments. The newly proposed, UT-Based UTSF scheme is applied to the navigation of a mobile robot in an unstructured environment as well as structured environment, and its performance is verified by the computer simulation and the experiment.

• International Journal of Reliability and Applications
• /
• v.3 no.1
• /
• pp.1-16
• /
• 2002

In reliability engineering, the bathtub-shaped hazard rates play an important role in survival analysis and many other applications as well. For the bathtub-shaped, initially the hazard rate decreases from a relatively high value due to manufacturing defects or infant mortality to a relatively stable middle useful life value and then slowly increases with the onset of old age or wear out. In this paper, we present a new two-parameter lifetime distribution function, called the Loglog distribution, with Vtub-shaped hazard rate function. We illustrate the usefulness of the new Vtub-shaped hazard rate function by evaluating the reliability of several helicopter parts based on the data obtained in the maintenance malfunction information reporting system database collected from October 1995 to September 1999. We develop the S-Plus add-in software tool, called Reliability and Safety Assessment (RSA), to calculate reliability measures include mean time to failure, mean residual function, and confidence Intervals of the two helicopter critical parts. We use the mean squared error to compare relative goodness of fit test of the distribution models include normal, lognormal, and Weibull within the two data sets. This research indicates that the result of the new Vtub-shaped hazard rate function is worth the extra function-complexity for a better relative fit. More application in broader validation of this conclusion is needed using other data sets for reliability modeling in a general industrial setting.

• Journal of Korea Water Resources Association
• /
• v.46 no.12
• /
• pp.1181-1191
• /
• 2013

This study have implemented finding the optimal water temperature parameter set for Hapcheon dam reservoir using CE-QUAL-W2 model. In particular the sensitivity analysis was carried out for four water temperature parameters of wind sheltering coefficient (WSC), radiation heat coefficient (BETA), light extinction coefficient (EXH2O), heat exchange coefficient at the channel bed (CBHE). Firstly, WSC, BETA, EXH2O shows relatively high sensitivity in common during April to September, and CBHE does during August to November. Secondly, as a result of identifying depth range of parameter influence, BETA and EXH2O show 0~9 m and 8~14 m which is thermocline layer close to water surface, CBHE is deep layer 12 m away from bottom. Finally, applying annual or monthly optimal parameter sets indicates that the bias between two sets does not show much differences for WSC and CBHE parameters, but BETA and EXH2O parameters show $0.20^{\circ}C$ and $0.51^{\circ}C$ of monthly average biases for two parameter sets. In particular the bias reveals to be $0.4^{\circ}C$ and $1.09^{\circ}C$ during May and August that confirms the necessity of use of monthly parameters during that season. It is claimed that the current operational custom use of annual parameters in calibration of reservoir water quality model requires the improvement of using monthly parameters.

• Wind and Structures
• /
• v.38 no.3
• /
• pp.215-229
• /
• 2024

Guyed mast structures exhibit characteristics such as high flexibility, low mass, small damping ratio, and large aspect ratio, leading to a complex wind-induced vibration response mechanism. This study analyzed the time- and frequency-domain characteristics of the wind-induced response of a guyed mast structure using measured acceleration response data obtained from the Shenzhen Meteorological Gradient Tower (SZMGT). Firstly, 734 sets of 1-hour acceleration samples measured from 0:00 October 1, 2021, to 0:00 November 1, 2021, were selected to study the vibration shapes of the mast and the characteristics of the generalized extreme value (GEV) distribution. Secondly, six sets of typical samples with different vibration intensities were further selected to explore the Gaussian property and modal parameter characteristics of the mast. Finally, the modal parameters of the SZMGT are identified and the identification results are verified by finite element analysis. The findings revealed that the guyed mast vibration shape exhibits remarkable diversity, which increases nonlinearly along the height in most cases and reaches a maximum at the top of the tower. Moreover, the GEV distribution characteristics of the 734 sets of samples are closer to the Weibull distribution. The probability distribution of the structural wind vibration response under strong wind is in good agreement with the Gaussian distribution. The structural response of the mast under wind loading exhibits multiple modes. As the structural response escalates, the first three orders of modal energy in the tower display a gradual increase in proportion.

• Journal of Wetlands Research
• /
• v.22 no.1
• /
• pp.15-23
• /
• 2020

The purpose of this study is to investigate how the degree of distribution influences the calibration of snow and runoff in distributed hydrological models using a multi-criteria calibration method. The Hydrology Laboratory-Research Distributed Hydrologic Model (HL-RDHM) developed by NOAA-National Weather Service (NWS) is employed to estimate optimized parameter sets. We have 3 scenarios depended on the model complexity for estimating best parameter sets: Lumped, Semi-Distributed, and Fully-Distributed. For the case study, the Durango River Basin, Colorado is selected as a study basin to consider both snow and water balance components. This study basin is in the mountainous western U.S. area and consists of 108 Hydrologic Rainfall Analysis Project (HRAP) grid cells. 5 and 13 parameters of snow and water balance models are calibrated with the Multi-Objective Shuffled Complex Evolution Metropolis (MOSCEM) algorithm. Model calibration and validation are conducted on 4km HRAP grids with 5 years (2001-2005) meteorological data and observations. Through case study, we show that snow and streamflow simulations are improved with multiple criteria calibrations without considering model complexity. In particular, we confirm that semi- and fully distributed models are better performances than those of lumped model. In case of lumped model, the Root Mean Square Error (RMSE) values improve by 35% on snow average and 42% on runoff from a priori parameter set through multi-criteria calibrations. On the other hand, the RMSE values are improved by 40% and 43% for snow and runoff on semi- and fully-distributed models.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.26 no.4
• /
• pp.217-224
• /
• 2014

Cochlodinium polykrikoides is a typical harmful algal species which generates the red-tide in the coastal zone, southern Korea. Accurate algal growth model can be established and then the prediction of the red-tide occurrence using this model is possible if the information on the optimal growth model parameters are available because it is directly related between the red-tide occurrence and the rapid algal bloom. However, the limitation factors on the algal growth, such as light intensity, water temperature, salinity, and nutrient concentrations, are so diverse and also the limitation function types are diverse. Thus, the study on the algal growth model development using the available laboratory data set on the growth rate change due to the limitation factors are relatively very poor in the perspective of the model. In this study, the growth model on the C. polykrikoides are developed and suggested as the optimal model which can be used as the element model in the red-tide or ecological models. The optimal parameter estimation and an error analysis are carried out using the available previous research results and data sets. This model can be used for the difference analysis between the lab. condition and in-situ state because it is an optimal model for the lab. condition. The parameter values and ranges also can be used for the model calibration and validation using the in-situ monitoring environmental and algal bloom data sets.