• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07a
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• pp.177-180
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• 2002

Thickness dependence of crystallographic orientation of diol based sol-gel derived PZT(52/48) films on dielectric and piezoelectric properties was investigated The thickness of each layer by one time spinning was about 0.2 $\mu\textrm{m}$, and crack-free films was successfully deposited on 4 inches Pt/Ti/SiO$_2$/Si substrates by 0.5 mol solutions in the range from 0.2 $\mu\textrm{m}$ to 3.8 $\mu\textrm{m}$. Excellent P-E hysteresis curves were achieved without pores or any defects between interlayers. As the thickness increased , the (111) preferred orientation disappeared from 1$\mu\textrm{m}$ to 3 $\mu\textrm{m}$ region, and the orientation of films became random above 3 $\mu\textrm{m}$. Dielectric constants and longitudinal piezoelectric coefficient d$\_$33/, measured by pneumatic method were saturated around the value of about 1400 and 300 pC/N respectively above the thickness of 0.8 7m. A micromachined piezoelectric cantilever have been fabricated using 0.8 $\mu\textrm{m}$ thickness PZT (52/48) films. PZT films were prepared on Si/SiN$\_$x/SiO$_2$/Ta/Pt substrate and fabricated unimorph cantilever consist of a 0.8 fm thick PZT layer on a SiNx elastic supporting layer, which becomes vibration when ac voltage is applied to the piezoelectric layer. The dielectric constant (at 100 kHz) and remanent polarization of PZT films were 1050 and 25 ${\mu}$C/$\textrm{cm}^2$, respectively. Electromechanical characteristics of the micromachined PZT cantilever in air with 200-600 $\mu\textrm{m}$ lengths are discussed in this presentation.

• Journal of Korean Critical Care Nursing
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• v.13 no.1
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• pp.44-62
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• 2020

Purpose : The purpose of this study was to systematically review the measurement tools that are used to assess the pain of intensive care unit (ICU) patients. Method : In this systematic review, the studies published between 2009 and 2018 were selected based on the PRISMA flow chart. Data sources included MEDLINE, EMBASE, CINAHL, and Cochran. We assessed the quality of pain assessment tools reported in individual studies using Terwee et al.'s the Quality Criteria for Measurement Properties. Results : We reviewed 67 studies and 12 pain assessment tools that included two self-reported, seven observational, and three multifaced tools with observations and physiological indicators. The most frequently used tool was the Critical Care Pain Observation Tool. The Multidimensional Observational Pain Assessment Tool was rated the highest quality. Nine of the ten tools that included observations reported content validity, four reported construct validity and nine reported correlation coefficient. Conclusion : It was found that observational tools are appropriate for assessing pain in ICU patients with limited communication skills. To increase the validity and reliability of pain assessment in ICU patients, further research on the physiological indicators of pain is needed.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.13 no.4
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• pp.111-121
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• 1993

Changes in bed forms and subsequent changes in channel roughness by changes in water discharge are discussed with the field data collected from some alluvial rivers in Korea. This study is limited to the following condition of river flow: (1) Medium size alluvial rivers with their widths of 100 m more or less, (2) Straight and prismatic river reach with no additional causes for energy loss but bed friction, (3) Lower-flow regime with Froude number less than 0.5. Major conclusions obtained from this study can be summarized as follows: (1) For the channels considered in this study, the bed roughness expressed by Manning's n increases from 0.02 for the plane beds with no sediment motion to 0.05 for the dune beds, (2) The roughness coefficient for alluvial channels should not be estimated from Strickler-type equations developed for the fixed beds, (3) The method for determining the channel roughness suggested in the present guideline for river works, River Structure Standard, appears to be lack of generality. More research based on the field data collected in Korea is needed in order to improve the existing methods.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.2B
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• pp.165-173
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• 2011

In this study, FESWMS FST2DH model was used to analyze the change of flow characteristics after making the riparian forest. The additional flow resistance is calculated based on the drag-force concept acting on each tree and the lateral momentum transfer between planted and non-planted zone could be satisfactorily reproduced by parabolic turbulence model in this depth-averaged 2-D numerical model. For model validation, the simulated velocities were compared with the measured data, showing good agreement in both tree density cases of experiments. The previous method using a proper Manning's n coefficient gives reasonable solutions only to evaluate the conveyance, but the calculated approach velocity at each tree was different from realistic value. The proposed procedure could be widely used to evaluate hydraulic effects of riparian trees in practical engineering.

• Journal of computational fluids engineering
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• v.18 no.2
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• pp.66-71
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• 2013

In this paper, the supersonic flows around space launch vehicles have been numerically simulated by using a 3-D RANS flow solver. The focus of the study was made for investigating plume-induced flow separation(PIFS). For this purpose, a vertex-centered finite-volume method was utilized in conjunction with 2nd-order Roe's FDS to discretize the inviscid fluxes. The viscous fluxes were computed based on central differencing. The Spalart-Allmaras model was employed for the closure of turbulence. The Gauss-Seidel iteration was used for time integration. To validate the flow solver, calculation was made for the 0.04 scale model of the Saturn-5 launch vehicle at the supersonic flow condition without exhaust plume, and the predicted results were compared with the experimental data. Good agreements were obtained between the present results and the experiment for the surface pressure coefficient and the Mach number distribution inside the boundary layer. Additional calculations were made for the real scale of the Saturn-5 configuration with exhaust plume. The flow characteristics were analyzed, and the PIFS distances were validated by comparing with the flight data. The KSLV-1 is also simulated at the several altitude conditions. In case of the KSLV-1, PIFS was not observed at all conditions, and it is expected that PIFS is affected by the nozzle position.

• Proceedings of the KSME Conference
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• 2002.08a
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• pp.687-690
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• 2002

Multimode boundary-layer transition on a NACA0012 airfoil is experimentally investigated under periodically passing wakes and the moderate level of free-stream turbulence. The periodic wakes are generated by rotating circular cylinders clockwise or counterclockwise around the airfoil. The free-stream turbulence is produced by a grid upstream of the rotating cylinder, and its intensity(Tu) at the leading edge of the airfoil is $0.5\;or\;3.5\;{\%}$. The Reynolds number ($Re_c$) based on chord length (C) of the alrfoil is $2.0{\times}10^5$, and Strouhal number ($St_c$) of the passing wake is about 0.7. Time- and phase-averaged streamwise mean velocities and turbulence fluctuations are measured with a single hot-wire probe, and especially, the corresponding wall skin friction is evaluated using a computational Preston tube method. The wake-passing orientation changes pressure distribution on the airfoil in a different manner irrespective of the free-stream turbulence. Regardless of free-stream turbulence level, turbulent patches for the receding wakes propagate more rapidly than those for the approaching wake because adverse pressure gradient becomes larger. The patch under the high free-stream turbulence ($Tu=3.5{\%}$) grows more greatly in laminar-like regions compared with that under the low background turbulence ($Tu=0.5{\%}$) in laminar regions. The former, however, does not greatly change the original turbulence level in the very near-wall region while the latter does it. At further downstream, the former interacts vigorously with high environmental turbulence inside the pre-existing transitional boundary layer and gradually lose his identification, whereas the latter keep growing in the laminar boundary layer. The calmed region is more clearly observed under the lower free-stream turbulence level and for the receding wakes. The calmed region delays the breakdown further downstream and stabilizes more the boundary layer.

• Journal of The Korean Society of Integrative Medicine
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• v.4 no.3
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• pp.93-100
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• 2016

Purpose : The purpose of this research is to measure the correlations among sleep quality, depression and department satisfaction in the students enrolled in the nursing college located in the B city. Method : 268 students enrolled in the nursing college located in the B city participated in this research from the 1st May 2016 to the 31st May 2016. SPSS 18.0 was applied to the collected data to calculate the frequency, percentage, average and standard deviation. In addition, t-test, ANOVA, Scheffe test and Pearson correlation coefficient were used for the analysis. Result : The result of the average sleep quality, depression and department satisfaction in the nursing college students were measured to be $2.41{\pm}0.57$, $3.59{\pm}0.50$ and $3.56{\pm}0.57$ respectively. The sleep quality based on the general characteristics indicated a significant difference when applied to the health status(F=4.46, p=.012). The depression indicated a significant difference when applied to the living with parents(t=-2.18, p=.030) and relationship with friends(F=8.62, p=.000). The department satisfaction indicated a significant difference when applied to the grade(F=3.45, p=.017), personality(F=3.46, p=.033), and reason for applying for their department(F=2.49, p=.044). As a result of analyzing the correlations among sleep quality, depression and department satisfaction in the nursing college students, the sleep quality indicated a negative correlation with the depression(r=-.528, p=.000) and a positive correlation with the department satisfaction(r=.144, p=.018). The depression indicated a negative correlation with the department satisfaction(r=.119, p=.051). Conclusion : It is necessary to conduct a replication research by increasing the number of the research subjects. In addition, it is necessary to conduct a systematic research on the factors influential on sleep quality, depression and department satisfaction in order to develop a program capable of enhancing the sleep quality and decreasing the depression.

• Journal of Agricultural Extension & Community Development
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• v.4 no.1
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• pp.305-315
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• 1997

The propose of this study was to analyze the relationships among the levels of training & development evaluation (reaction, learning, transfer). The study has been conducted on 730 trainees who attended in the basic accounting program in L training and development institution through three incidents of tracked research such as reaction survey right after the conclusion of training, learning evaluation through test, and an evaluation of the transferability after 3 months of training. Questionnaires and test papers for analyses were used after their reliability, validity, difficulty, and discrimination have been verified on a pre-test. The research has been conducted for six months from 4 March 1996 to the end of August 1996, and data have been collected through direct research and survey through mail. The collected data have been worked on at SAS program for Windows with a statistical significance level of 5%. Statistical method that had been used was Pearson's correlation coefficient. The result and conclusion acquired from this study were as follows: Between reaction and learning, learning and transfer of training, only a weak positive correlation exists and explanation or prediction variance showing hierarchical relationship was quite weak with 1%. Thus, this research not only does not strongly support Kirkpatrick(1976)'s hierarchical model of $reaction{\rightarrow}learning{\rightarrow}transfer$, but also indicates that the separate measurement on each levels of training evaluation needs to be done. On the other hand, there was a relatively strong positive correlation between reaction and transfer of training. Based on the result, the conclusion, and the restriction perceived through this study, the following suggestions were made. 1. There is a need to empirically analyze and verify the hierarchy of all levels of training evaluation including the evaluation of the fourth level (result) such as organizational productivity, organizational satisfaction, and separation rate. 2. A great deal of efforts will be needed to systematically analyze what the relationships are among the methods measuring the level of evaluation of the training and development, and to apply this result to the training field.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.4
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• pp.106-114
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• 2016

In this paper, we propose an efficient integer inverse transform structure for vp9 decoder. The proposed structure is a hardware structure which is easy to control and requires less hardware resources, and shares algorithms for realizing entire DCT(Discrete Cosine Transform), ADST(Asymmetric Discrete Sine Transform) and WHT(Walsh-Hadamard Transform) in vp9. The integer inverse transform for vp9 google model has a fast structure, named butterfly structure. The integer inverse transform for google C model, unlike universal fast structure, takes a constant rounding shift operator on each stage and includes an asymmetrical sine transform structure. Thus, the proposed structure approximates matrix coefficient values for all transform mode and is used to matrix operation method. With the proposed structure, shared operations for all inverse transform algorithm modes can be possible with reduced number of multipliers compared to the butterfly structure, which in turn manages the hardware resources more efficiently.

• Bulletin of the Korean Chemical Society
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• v.35 no.12
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• pp.3637-3641
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• 2014

In this study, we analyzed the toxicity of mixtures of dimethylformamide (DMF) and methyl ethyl ketone (MEK) or DMF and toluene (TOL) and predicted their toxicity using quantitative structure-activity relationships (QSAR). A QSAR model for single substances and mixtures was analyzed using multiple linear regression (MLR) by taking into account the statistical parameters between the observed and predicted $EC_{50}$. After preprocessing, the best subsets of descriptors in the learning methods were determined using a 5-fold cross-validation method. Significant differences in physico-chemical properties such as boiling point (BP), specific gravity (SG), Reid vapor pressure (rVP), flash point (FP), low explosion limit (LEL), and octanol/water partition coefficient (Pow) were observed between the single substances and the mixtures. The $EC_{50}$ of the mixture of DMF and TOL was significantly lower than that of DMF. The mixture toxicity was directly related to the mixing ratio of TOL and MEK (MLR $EC_{50}$ equation = $1.76997-1.12249{\times}TOL+1.21045{\times}MEK$), as well as to SG, VP, and LEL (MLR equation $EC_{50}=15.44388-19.84549{\times}SG+0.05091{\times}VP+1.85846{\times}LEL$). These results show that QSAR-based models can be used to quantitatively predict the toxicity of mixtures used in manufacturing industries.