• Journal of Korean Academy of Nursing
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• v.49 no.4
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• pp.361-374
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• 2019

Purpose: This study was conducted to evaluate the effectiveness of autogenic training on stress responses through a systematic review and meta-analysis. Methods: A systematic search was conducted using eight core electronic databases (Embase, CENTRAL, Medline, CINAHL, PsycInfo, DBpia, KISS, and RISS). To estimate the effect size, a meta-analysis of the studies was performed using RevMan 5.3.5 program. Results: A total 21 studies out of 950 studies were included in the review, and 11 were included for meta-analysis. These studies showed that autogenic training decreased anxiety and depression, and increased the high frequency of heart rate variability. Calculations to understand the effect of autogenic training on anxiety, through a meta-analysis, observed a reduction effect of anxiety score by 1.37 points (n=85, SMD=-1.37: 95% CI -2.07 to -0.67), in the studies on short-term intervention targeting healthy adults. On the other hand, similar calculations to understand the effect of autogenic training on depression observed, a reduction effect on the depression score by 0.29 point (n=327, SMD=-0.29: 95% CI -0.50 to -0.07), in the studies on long term intervention targeting the patient group. Conclusion: Autogenic training is effective for adults' stress management, and nurses will be able to effectively perform autogenic training programs for workers' stress relief at the workplace.

• Journal of the Korean Society of Radiology
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• v.13 no.7
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• pp.987-994
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• 2019

Low energy x-rays that occur in the low tube voltage radiography of general radiography are absorbed strongly in the body and do not aid image quality enhancement. This study maintains titer in general radiography while using tube current that are proportional to density and the tube voltage 15% principle according to density to reduce patient exposure doses, and area doses and entrance surface doses were measured to compare patient exposure doses. In hand, knee, abdomen, and skull radiography, kVp was increased to 115% and mAs was decreased to 50% and kVp was decreased to 85% while mAs was increased to 200% and area doses and entrance surface doses were measured to compare relative doses. Also, 5 places in each image were set, density was measured, and Kruskal wallis H test was conducted to observe significance probabilities between groups. To fix density, kVp was increased to 115% and mAs was decreased to 50% and after measurements of mean area doses and entrance surface doses were made by each part, each decreased to 58.68% and 59.85% when standard doses were set to 100%, and each increased to 147.28% and 159.9% when kVp was decreased to 85% and mAs was increased to 200%. Comparisons of density changes showed that hand, knee, abdomen, and skull radiography all displayed significance probabilities>0.05, showing no changes in concentration. Radiography that increases kVp and lowers mAs through reasonable calculations within ranges that don't affect resolution and contrast seems to be a simple way to decrease patient exposure doses.

• Geomechanics and Engineering
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• v.5 no.2
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• pp.143-164
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• 2013

Calculation of seismic displacements in reinforced slopes plays a crucial role in appropriate design of these structures however current analytical methods result indifferent values for permanent displacements of the slope. In this paper, based on limit equilibrium and using the horizontal slices method, a new formulation has been proposed for estimating the seismic displacements of a reinforced slope under earthquake records. In this method, failure wedge is divided into a number of horizontal slices. Assuming linear variations for tensile forces of reinforcements along the height of the slope, the coefficient of yield acceleration has been estimated. The simplicity of calculations and taking into account the frequency content of input triggers are among the advantages of the present formulation. Comparison of the results shows that the yield acceleration calculated by the suggested method is very close to the values resulted from other techniques. On the other hand, while there is a significant difference between permanent displacements, the values obtained from the suggested method place somehow between those calculated by the other techniques.

• Journal of Mechanical Science and Technology
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• v.20 no.12
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• pp.2061-2078
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• 2006

The main purpose of this paper is to establish the high temperature structural integrity evaluating procedures for the next generation reactors, which are to be operated at over 500$^{\circ}C$ and for 60 years. To do this, comparison studies of the high temperature structural design codes and assessment procedures such as the ASME-NH (USA), RCC-MR (France), DDS (Japan), and R5 (UK) are carried out in view of the accumulated inelastic strain and the creep-fatigue damage evaluations. Also the application procedures of the ASME-NH rules with the actual thermal and structural analysis results are described in detail. To overcome the complexity and the engineering costs arising from a real application of the ASME-NH rules by hand, all the procedures established in this study such as the time-dependent primary stress limits, total accumulated creep ratcheting strain limits, and the creep-fatigue damage limits are computerized and implemented into the SIE ASME-NH program. Using this program, the selected high temperature structures subjected to two cycle types are evaluated and the parametric studies for the effects of the time step size, primary load, number of cycles, normal temperature for the creep damage evaluations and the effects of the load history on the creep ratcheting strain calculations are investigated.

• Journal of Korean Society for Atmospheric Environment
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• v.17 no.E1
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• pp.9-16
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• 2001

To evaluate the correct separation capacity of cascade impactor for liquid aerosol, theoretical and experimental calculations of 50% cut-off diameter(ECOD(sub)50) were performed. A recalculation method of original diameter for hemispheric liquid aerosol collected on casecad impactor is also proposed newly using fixation technique. Calculated values for theoretical (ECOD(sub)50) of 40stage cascade impactor are 20, 6.4, 2.8, and 1.4$\mu\textrm{m}$ at 1st- ,2nd-, 3rd- and 4th-stage, respectively. A good agreement between the result of theoretical (ECOD(sub)50) and that og experimental ones was obtained at Stage 2 and 3. On the other hand, relatively large differences were found at Stage 1 and 4. Fixation for liquid aerosols using ${\alpha}$-cyanoacrylate monomer was performed successfully. The orignal diameter of liquid aerosols collected on each stage was calculated. The maximum levels of number size distribution curves at each stage are 19.8, 6.5, 3.1 and 1.5 $\mu\textrm{m}$ at 1st-, 2nd-, 3rd- and 4th-stage, respectively. The distortion of separation capacity of cascade impactor due to the split, merger, disappearance, and evaporation of liquid aerosols in the fluid did not occur.

• Journal of the Korean earth science society
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• v.33 no.5
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• pp.434-449
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• 2012

The Mesozoic leucocratic granite in the northeastern margin of the Taebaeksan Basin was transformed to protomylonite and mylonite. Mylonitic foliations generally strike to NWWNW and dip to NE with the development of a sinistral strike-slip (top-to-the-northwest) shear sense. Grain-size reduction of feldspar in the mylonitized leucocratic granite occurred due to fracturing, myrmekite formation and neocrystallization of albitic plagioclase along the shear fractures of K-feldspar porphyroclasts. As the deformation proceeded, compositional layering consisting of feldspar-, quartz- and/or muscovite-rich layers developed in the mylonite. In the feldspar-rich layer, fine-grained albitic plagioclase and interstitial K-feldspar were deformed dominantly by granular flow. On the other hand, quartz-rich layers containing core-mantle and quartz ribbons structures were deformed by dislocation creep. Based on calculations from conventional two-feldspar and ternary feldspar geothermometers, mylonitization temperatures of the leucocratic granite range from 360 to $450^{\circ}C$. It thus indicates that the mylonitization has occurred under greenschist-facies conditions. Based on the geochemical features and previous chronological data, the leucocratic granite was emplaced during the Middle Jurassic at volcanic arc setting associated with crustal thickening. And then the mylonitization of the granite occurred during the late Middle to Late Jurassic (150-165 Ma). Therefore, the mylonitization of the Jurassic granitoids in the Taebaeksan Basin was closely related to the development of the Honam shear zone.

• Journal of the Korean Geotechnical Society
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• v.18 no.2
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• pp.13-21
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• 2002

A new method called S-SRICOS is proposed to predict the local scour depth around bridge piers. The S-SRICOS method is a simplified version of the SRICOS method which was developed to predict the scour depth versus time curve around bridge piers. The SRICOS method which considers the time effect based on the soil properties and the hydraulic parameters can handle a multi-flood hydrograph and multi-layer soil systems with the SRICOS program. An attempt was made to simplify the method to the point where only hand calculations would be required. The concept of the equivalent time was developed leer this purpose. The S-SROICOS method requires only 4 parameters such as pier width, design bridge life, design velocity corresponding to the design bridge life, and initial scour rate of the soil. The S-SRICOS method was verified against 55 cases of the scour depth results using the SRICOS method.

• Proceedings of the KSME Conference
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• 2001.11b
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• pp.585-590
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• 2001

The hemodynamic characteristics were compared using commercial CFD code for the stenosed coronary and abdominal arteries. Numerical calculations were carried out in the axisymmetric arteries over the stenotic diameter ratios ranging from 0.25 to 0.875 (6 cases) employing the typical physiological flow conditions. In case of the coronary artery, there was only one recirculation zone observed distal to the stenosis throat during the major portion of the period. However, in case of the abdominal aorta, there were complex recirculation regions found proximal and distal to stenosis throat. For both models, the wall shear stresses(WSS) increased sharply in the converging stenosis, reaching a peak just upstream of the throat, and became negative or low values in the post-stenotic recirculation region. As the results, the oscillatory shear index(OSI) was abruptly increased at the stenosis throat. For the coronary stenosis model, the second peak in the OSI was observed distal to the stenosis. The distance between the first peak and the second peak was increased as the degree of the stenosis was raised. On the orther hand, the abdominal stenosis model showed a complex oscillatory behavior in the OSI index and did not showed such a strong second peak. As the degree of stenosis was increased, recirculation regions of the both arteries were extended much longer and flow pattern became more complex.

• Journal of Veterinary Clinics
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• v.32 no.1
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• pp.73-77
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• 2015

There has been increasing attention on sample size requirements in peer reviewed medical literatures. Accordingly, a statistically-valid sample size determination has been described for a variety of medical situations including diagnostic test accuracy studies. If the sample is too small, the estimate is too inaccurate to be useful. On the other hand, a very large sample size would yield the estimate with more accurate than required but may be costly and inefficient. Choosing the optimal sample size depends on statistical considerations, such as the desired precision, statistical power, confidence level and prevalence of disease, and non-statistical considerations, such as resources, cost and sample availability. In a previous paper (J Vet Clin 2012; 29: 68-77) we briefly described the statistical theory behind sample size calculations and provided practical methods of calculating sample size in different situations for different research purposes. This review describes how to calculate sample sizes when assessing diagnostic test performance such as sensitivity and specificity alone. Also included in this paper are tables and formulae to help researchers for designing diagnostic test studies and calculating sample size in studies evaluating test performance. For complex studies clinicians are encouraged to consult a statistician to help in the design and analysis for an accurate determination of the sample size.

• Journal of Power Electronics
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• v.18 no.3
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• pp.892-901
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• 2018

SiC MOSFETs have been used to improve system efficiency in high frequency converters due to their extremely high switching speed. However, this can result in undesirable parasitic oscillations in practical systems. In this paper, models of the key components are introduced first. Then, theoretical formulas are derived to calculate the switching oscillation frequencies after full turn-on and turn-off in clamped inductive circuits. Analysis indicates that the turn-on oscillation frequency depends on the power loop parasitic inductance and parasitic capacitances of the freewheeling diode and load inductor. On the other hand, the turn-off oscillation frequency is found to be determined by the output parasitic capacitance of the SiC MOSFET and power loop parasitic inductance. Moreover, the shifting regularity of the turn-off maximum peak voltage with a varying switching speed is investigated on the basis of time domain simulation. The distortion of the turn-on current is theoretically analyzed. Finally, experimental results verifying the above calculations and analyses are presented.