• Journal of Korean Society for Atmospheric Environment
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• v.21 no.1
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• pp.1-14
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• 2005

In this study, a Long Path Differential Optical Absorption Spectroscopy system (K-JIST LP-DOAS) has been used to simultaneously measure atmospheric monoaromatic hydrocarbons and other trace compounds. The validity of the K-JIST LP-DOAS for measuring atmospheric monoaromatic hydrocarbons was tested during a field campaign between 12 February and 14 March 2003 at an urban site in Seoul, Korea through inter-comparative measurements against a collocated on-line Gas Chromatography (GC) system. The concentrations of benzene, toluene, p-xylene, and m-xylene were measured with the K-JIST LP-DOAS system in the UV region (239～302 nm) over a 740 m beam path. For the other trace compounds, a longer spectral range (299～362 nm) was used. In order to remove the interference of atmospheric abundant species (such as oxygen, sulfur dioxide and ozone), two oxygen optical density spectra obtained at two pathlengths, 697 and 1133m, and reference spectra of sulfur dioxide and ozone were incorporated in the fitting procedure. The mean concentrations measured by our LP-DOAS during the measurement period were 0.77 ($\pm$0.38) ppbv for benzene, 3.68 ($\pm$1.90) ppbv for toluene, 0.41 ($\pm$0.19) ppbv for p-xylene, 0.54 ($\pm$0.24) ppbv for m-xylene. The concentration data of benzene, toluene, p-xylene and m-xylene obtained by our LP-DOAS were found to be in relatively good correlations with those of the online GC system. Pearson's coefficients in the observed concentrations between LP-DOAS and on-line GC were 0.84 for benzene, 0.83 for toluene and 0.65 for m,p-xylene. This study suggests that the LP-DOAS system can be used to provide reliable information on both the mixing ratios and temporal distribution characteristics of monoaromatic hydrocarbons in the urban air.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.2 no.3
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• pp.23-29
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• 2009

The heart sends blood to the body with heart rate. When heart rate for men is from 60 to 80 per minute, he is generally normal. However, if heart rate is less than the normal heart rate, the symptom is called by bradycardia. Otherwise, the symptom is called by tachycardia. These symptoms make him even to death. Therefore, heartbeat rate has a very important role in a healthy life. In this study, we studied on auto-extracting methods of heart rates from ECG, and compared them with those measured by naked eyes. The first auto-extracting method employs the 2-order differential equations to extract heart rate. The second method uses the autocorrelation coefficients to detect heart rate. To verify its efficacy and validity in practical applications, these method has been applied to MIT/BIH database.

• Journal of Korea Water Resources Association
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• v.41 no.10
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• pp.969-982
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• 2008

As hydrological models have been progressively developed, they are recognized as appropriate tools to manage water resources. Especially, the need to evaluate the effects of landuse and climate change on hydrological phenomena has been increased, which requires powerful validation methods for the hydrological models to be employed. As measured streamflow data at many locations may not be available, or include significant errors in application of hydrological models, streamflow data simulated by models only might be used to conduct hydrological analysis. In many cases, reducing errors in model simulations requires a powerful model validation method. In this research, we demonstrated a validation methodology of SWAT model using observed flow in two basins with different physical characteristics. First, we selected two basins, Gap-cheon basin and Yongdam basin located in the Guem River Basin, showing different hydrological characteristics. Next, the methodology developed to estimate parameter values for the Gap-cheon basin was applied for estimating those for the Yongdam basin without calibration a priori, and sought for validation of the SWAT. Application result with SWAT for Yongdam basin showed $R_{eff}$ ranging from 0.49 to 0.85, and $R^{2}$ from 0.49 to 0.84. As well, comparison of predicted flow and measured flow in each subbasin showed reasonable agreement. Furthermore, the model reproduced the whole trends of measured total flow and low flow, though peak flows were rather underestimated. The results of this study suggest that SWAT can be applied for predicting effects of future climate and landuse changes on flow variability in river basins. However, additional studies are recommended to further verify the validity of the mixed method in other river basins.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.1A
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• pp.9-18
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• 2009

This paper introduces the application of DE (Differential Evolutionary) method for the estimation of tensile force of the externally prestressed tendon. The proposed technique, a SI (System Identification) method using the DE algorithm, can make global solution search possible as opposed to classical gradient-based optimization techniques. The numerical tests show that the proposed technique employing DE algorithm is a useful method which can detect the effective nominal diameters as well as estimate the exact tensile forces of the externally prestressed tendon with an estimation error less than 1% although there is no a priori information about the identification variables. In addition, the validity of the proposed technique is experimentally proved using a scale-down model test considering the serviceability state condition without and with the loss of the prestressed force. The test results prove that the technique is a feasible and effective method that can not only estimate the exact tensile forces and detect the effective nominal diameters but also inspect the damping properties of test model irrespective of the loss of the prestressed force. The 2% error of the estimated effective nominal diameter is due to the difference between the real tendon diameter with a wired section and the FE model diameter with a full-section. Finally, The accuracy and superiority of the proposed technique using the DE algorithm are verified through the comparative study with the existing theories.

• Journal of the Korean Society of School Health
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• v.14 no.2
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• pp.249-268
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• 2001

This study was carried out to identify the effects of an art therapy program based on reality therapy on the weight control, body image, and self-esteem of college students. The program was developed by the authors. The design was a pretest-post test control group design. The subjects were college students attending M college : 8 in experimental group A, 6 in experimental group 2, who wanted to control their body weight and 16 in the control group who didn't attend the program those in the experimental group attended the program once (group A) or twice (group B) per week meeting a total of six times. The data were analyzed by quantity method (SPSS 10.0 program) and quality method(process analysis). The results were as follows : 1. The average obesity index of pre-test, post-test, and a follow-up test decreased from 8.9% to 6.1%, 3.7%. And the rate of decrease both pre-post and post-follow up were statistically significant 2. The average obesity index of group A decreased from 9.6% to 6.3%, 4.1% and the rate of decrease between pre and post were statistically significant. But the rate of decrease between post and follow-up were statistically not significant 3. The average obesity index of group B decreased from 7.8% to 5.8%, 3.1% and the rate of decrease between pre and post were not significant statistically. But the rate of decrease between post and follow-up were statistically significant 4. The average scores of pre and post body image increased and were statistically significant : group A from 129.0 to 153.5, group B from 127.7 to 155.2. 5. The average scores of pre and post semantic differential method increased and were statistically significant: group A from 38.1 to 44.1, group B from 38.0 to 45.0. 6. The average scores of pre and post self-esteem increased: group A increased from 37.3 to 40.3 and were statistically significant, group B increased from 36.5 to 39.5 but was statistically insignificant 7. The average scores of pre and post obesity rate, body image, semantic differential method and self-esteem in the control group were not statistically significant 8. The pre and post scores of body image(p=.001), semantic differential method(p=.001) and self-esteem(p=.039) between experimental and control group were statistically significant. 9. In Duncan multiple comparison, it was not statistically significant between group A and B, but statistically significant between group A and the control group, group B and the control group in obesity index, body image, semantic differential method. There was no statistically significance among the three groups in self esteem 10. In Duncan multiple comparison, group A gained higher scores than group B in obesity index(-1.2%), and self esteem(0. 3). Group B gained higher scores than group A in body image(3. 0), and semantic differential method(1. 0). So it is difficult to conclude whether group A or B is more effective. In conclusion, the art therapy program based on reality therapy was effective in weight the control program of college students: obesity was decreased, the scores of body image and semantic differential method and self-esteem were increased. The scores of group A were increased more than group Band were statistically significant, The time interval was a very important factor in this program. The recommendation is : the validity of this program has to be tested through various subjects and in various areas. And also this program has to be tested in other topics.

• Journal of the Korean Data and Information Science Society
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• v.25 no.3
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• pp.567-578
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• 2014

PEAS (performance enhancement attitude scale) has been used to measure attitude and disposition toward doping in elite athlete. It is constructed of 17-item, 6-point scale. The purpose of this study was to verify validity of the PEAS for Korean elite player through Rasch model. The scale was administered to 438 Korean elite players. Principal component analysis was used to verify unidimensionality using SPSS program. Rasch measurement computer program, WISTEPS, was used to estimate goodness-of-fit of items and category structure. Differenctial item functioning by gender was also estimated by the WINSTEPS program. All alpha level was set at 0.05. First, principal component analysis showed that unidimensionality is satisfied as over 20.0% of variance of eigenvalue. Second, category probabilities curve showed 5-point scale was better than 6-point scaled statistically. Third, seven items (1, 9, 10, 12, 13, 14, 17) in the 17-item were not good model fit and three items (3, 12, 13) were estimated as the differential item functioning. This study showed that 9-item, 5-point scale is better PEAS to Korean elite player.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.5A
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• pp.467-475
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• 2009

Existing studies have suggested Universal Curve only for supplemental damping by damper. Therefore net damping has been determined by means of arithmetic summation between intrinsic, aero-damping of cable and supplemental damping of damper. However linear combination approach by means of the arithmetic summation is not enough theoretical background. So validity of this approach should be verified in order to design adequate cable-damper system by engineers. This study establishes governing differential equation which can consider intrinsic, aero-damping and supplemental damping as well. And also analysis method is solved by combination of muller method and successive iteration method. Consequently, this study succeeds in verification for validity of linear combination approach. As a result of this study, linear combination approach is limitedly effective in case of low stiffness and optimum damping coefficient of damper, short distance from support to damper, lower vibration mode, low aero-damping, and normal windy environment. Whereas this study will be effective in case of opposite conditions, and existing studies or linear combination approach occur to further error. Meaning of this study presents exact solution for net damping of cable-damper system, and verifies linear combination approach by means of the analysis method. In the future, if monitoring of optimum damping coefficient of a damper against aero-damping is feasible on time, algorithm of this study will be available for control of cable and semi-active damper system such as magneto-rheological damper.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.1 no.1
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• pp.148-160
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• 1990

This paper reports on the development of the Children's Separtion Rating Scale(CSRS), its initial reliability and validity, and clinical/research utility with psychiatrically hospitalized children. The CSRS appears to be a reliable and valid instrument, and useful in distinguishing children's separation reaction from their general psychopathology. It may be also useful in aiding clinicians in differential diagnosis. This study points to the need for further understanding of children's psychiatric hospitalization in relation to their separation reaction and its possible untoward effects. Findings of this pilot study support the notion that inpatient treatment programs should address the developmental needs and abilities of the various age groups and the particular deficits reflected in their psychopathology.

• Steel and Composite Structures
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• v.36 no.6
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• pp.711-727
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• 2020

In the present research, the free vibration analysis of functionally graded (FG) nanocomposite deep spherical shells reinforced by graphene platelets (GPLs) on elastic foundation is performed. The elastic foundation is assumed to be Winkler-Past ernak-type. It is also assumed that graphaene platelets are randomly oriented and uniformly dispersed in each layer of the nanocomposite shell. Volume fraction of the graphene platelets as nanofillers may be different in the layers. The modified HalpinTsai model is used to approximate the effective mechanical properties of the multilayer nanocomposite. With the aid of the first order shear deformation shell theory and implementing Hamilton's principle, motion equations are derived. Afterwards, the generalized differential quadrature method (GDQM) is utilized to study the free vibration characteristics of FG-GPLRC spherical shell. To assess the validity and accuracy of the presented method, the results are compared with the available researches. Finally, the natural frequencies and corresponding mode shapes are provided for different boundary conditions, GPLs volume fraction, types of functionally graded, elastic foundation coefficients, opening angles of shell, and thickness-to-radius ratio.

• Journal of the Korean Institute of Intelligent Systems
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• v.12 no.6
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• pp.524-530
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• 2002

This note suggests a stepwise fuzzy moving sliding surface using Sugeno-type fuzzy system and presents a sliding mode control scheme using it. The fuzzy system has the angle of state error vector and the distance from the origin in the phase plane as inputs and a first-order linear differential equation as output. The surface initially passes arbitrary initial states and subsequently moves towards a predetermined surface via rotating or shifting. This method reduces the reaching and tracking time and improves robustness. Conceptually the slope of the Proposed fuzzy moving sliding surface increases stepwise in the stable region of the phase plane. The surface, however, rotates continuously because the surface is a fuzzy system. The asymptotic stability of the fuzzy sliding surface is proved. The validity of the proposed control scheme is shown in computer simulation for a second-order nonlinear system.