• The Journal of Advanced Prosthodontics
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• v.6 no.4
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• pp.253-258
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• 2014

PURPOSE. To compare marginal and internal gaps of zirconia substructure of single crowns with those of three-unit fixed dental prostheses. MATERIALS AND METHODS. Standardized Co-Cr alloy simulated second premolar and second molar abutments were fabricated and subsequently duplicated into type-III dental stone for working casts. After that, all zirconia substructures were made using $Lava^{TM}$ system. Marginal and internal gaps were measured in 2 planes (mesial-distal plane and buccal-palatal plane) at 5 locations: marginal opening (MO), chamfer area (CA), axial wall (AW), cusp tip (CT) and mid-occlusal (OA) using Replica technique. RESULTS. There were significant differences between gaps at all locations. The $mean{\pm}SD$ of marginal gap in premolar was $43.6{\pm}0.4{\mu}m$ and $46.5{\pm}0.5{\mu}m$ for single crown and 3-unit bridge substructure respectively. For molar substructure the $mean{\pm}SD$ of marginal gap was $48.5{\pm}0.4{\mu}m$ and $52.6{\pm}0.4{\mu}m$ for single crown and 3-unit bridge respectively. The largest gaps were found at the occlusal area, which was $150.5{\pm}0.5{\mu}m$ and $154.5{\pm}0.4{\mu}m$ for single and 3-unit bridge premolar substructures respectively and $146.5{\pm}0.4{\mu}m$ and $211.5{\pm}0.4{\mu}m$ for single and 3-unit bridge molar substructure respectively. CONCLUSION. Independent-samples t-test showed significant differences of gap in zirconia substructure between single crowns and three-unit bridge (P<.001). Therefore, the span length has the effect on the fit of zirconia substructure that is fabricated using CAD/CAM technique especially at the occlusal area.

• Proceedings of the Materials Research Society of Korea Conference
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• 1994.05a
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• pp.2-7
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• 1994

The dynamic fatigue life equation is applied to uniaxial tensile test. The resultant equations far the surface energy and fracture toughness are calculated with the data from the tensile test and compared with the ones from ASTM E399 test. During the crack propagation under model loading, the material of the crack tip undergoes the process of the elastic-plastic deformation in the uniaxial tensile test. The surface energy per unit area is proportional to the ratio of plastic and elastic elongations. The calculated fracture toughness of the metals are very well coincident to the ASTM E399's test results.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.4
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• pp.73-81
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• 2020

This study compared nursing service satisfaction and revisit intention of comprehensive nursing care unit and general care unit patients and confirmed the impact of nursing service satisfaction on revisit intention. We used data from 201 survey questionnaires collected from four general hospitals located in B-metropolitan area. Data were collected from Jun 1 to 30, 2019. The data were analyzed using x²-test, t-test, ANOVA, Scheffé test, Pearson's Correlation Coefficient, and Stepwise multiple regression. The results show that nursing service satisfaction was significantly higher in patients admitted to the comprehensive nursing care unit than in the general care unit. There was a significant correlation in increased nursing service satisfaction being associated with increased revisit intention. Among subcategories of nursing service satisfaction, Empathy and Tangibles were cited by 56% of the comprehensive nursing care unit and 40% of the general care unit. As a result of this study, it is necessary to prepare a nursing system that can continuously monitor nursing service satisfaction in order to increase hospital revisit intention and expand the implementation of a comprehensive nursing care unit system.

• The Journal of Engineering Geology
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• v.12 no.3
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• pp.319-332
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• 2002

This study is focused on the characterization of an effective hydraulic conductivity in each hydrogeologic unit assumed as an equivalent continuum medium in the granitic area. Four boreholes of 3" diameter were installed and a Multi-packer system was facilitated in the selected borehole. Various in-situ tests including the fracture logging, constant injection and fall-off tests, slug and pulse tests were carried out. A hydrogeologic unit was defined into the upper and lower zones based on the variation of fracture properties and hydraulic conductivities. The difference of the result obtained by the various hydraulic tests and the effective characterization techniques on rock mass permeability are also discussed. The effective hydraulic conductivity of the upper unit was measured by two times(5.27E-10 m/s~7.57E-10 m/s) that of the lower unit(2.45E-10 m/s~6.81E-10 m/s)through the constant injection and fall-off tests.

• Magazine of the Korean Society of Agricultural Engineers
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• v.26 no.4
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• pp.52-65
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• 1984

In general precise estimation of hourly of daily distribution of the long-term run-off should be very important in a design of source of irrigation. However, there have not been a satisfying method for forecasting of stationar'y long-term run-off in Korea. Solving this problem, this study introduces unit-hydrograph method frequently used in short-term run-off analysis into the long-term run-off analysis, of which model basin was selected to be Sumgin-river catchment area. In the estimation of effective rainfall, conventional method neglects the Soil moisture condition of catchment area, but in this study, the initial discharge (qb) occurred just before rising phase of the hydrograph was selected as the index of a basin soil moisture condition and then introduced as 3rd variable in the analysis of the reationship between cumulative rainfall and cumulative loss of rainfall, which built a new type of separation method of effective rainfall. In next step, in order to normalize significant potential error included in hydrological data, especially in vast catchment area, Snyder's correlation method was applied. A key to solution in this study is multiple correlation method or multiple regressional analysis, which is primarily based on the method of least squres and which is solved by the form of systems of linear equations. And for verification of the change of characteristics of unit hydrograph according to the variation of a various kind of hydrological charateristics (for example, precipitation, tree cover, soil condition, etc),seasonal unit hydrograph models of dry season(autumn, winter), semi-dry season (spring), rainy season (summer) were made respectively. The results obtained in this study were summarized as follows; 1.During the test period of 1966-1971, effective rainfall was estimated for the total 114 run-off hydrograph. From this estimation results, relative error of estimation to the ovservation value was 6%, -which is mush smaller than 12% of the error of conventional method. 2.During the test period, daily distribution of long-term run-off discharge was estimated by the unit hydrograph model. From this estimation results, relative error of estimation by the application of standard unit hydrograph model was 12%. When estimating by each seasonal unit bydrograph model, the relative error was 14% during dry season 10% during semi-dry season and 7% during rainy season, which is much smaller than 37% of conventional method. Summing up the analysis results obtained above, it is convinced that qb-index method of this study for the estimation of effective rainfall be preciser than any other method developed before. Because even recently no method has been developed for the estimation of daily distribution of long-term run-off dicharge, therefore estimation value by unit hydrograph model was only compared with that due to kaziyama method which estimates monthly run-off discharge. However this method due to this study turns out to have high accuracy. If specially mentioned from the results of this study, there is no need to use each seasonal unit hydrograph model separately except the case of semi-dry season. The author hopes to analyze the latter case in future sudies.

• Journal of Gifted/Talented Education
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• v.25 no.1
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• pp.119-138
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• 2015

This study analyzed the academic achievements on above-level testing of mathematics, physics, chemistry, and English in newly entering students of science specialized high schools. It can be expected that newly students of science high specialized schools have reached ceiling level in the middle school mathematics and science academic scores. Above-level testing(or off-level testing) is a test tool used to evaluate student's ability which are above-grade level. In this study, above-level testing tools were used to develop the same type examination paper of the 2013 Korean College Scholastic Ability Test(CSAT) in mathematics, physics, chemistry, and English. The conclusions of this study were as follow: First, the academic achievement level of science specialized high school freshmen were higher the average level of general high school senior because that over 50% of them are within the 5 grade of CSAT in mathematics, physics, and chemistry. In English, 19.3% science specialized high school freshmen have reached within the 5 grade of CSAT. Second, as a result of examining characteristics of academic achievement with respect to units of subjects, in mathematics, it was showed that the academic achievement of 'continuity and limit of a function' unit was higher, 'statistics' unit was lower. In physics, the academic achievement of 'Electricity and Magnetism' unit was higher, 'Waves and particles' unit was lower. In chemistry, the academic achievement of 'compounds in life' unit was higher, 'Air' unit was lower. In English, the academic achievement of 'practical sentence' of reading area was higher, 'Sentence' of writing area was lower. In conclusion, above-level testing provided a good strategy for identifying and determining appropriate programming interventions for gifted students who are two or more grade levels above their age-mates in achievements, aptitude, or ability.

• Proceedings of the IEEK Conference
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• 1998.10a
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• pp.1169-1172
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• 1998

We designed an ALU(Airthmetic Logic Unit) with BIST(Built-In Self Test), which is suitable for 32-bit DSP RISC processors. We minimized the area of this ALU by allowing different operations to share several hardware blocks. Moreover, we applied DFT(Design for Testability) to ALU and offered Bist(Built-In Self-Test) function. BIST is composed of pattern generation and response analysis. We used the reseeding method and testability design for the high fault coverage. These techniques reduce the test length. Chip's reliability is improved by testing and the cost of testing system can be reduced.

• International Area Studies Review
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• v.14 no.3
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• pp.363-387
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• 2010

This papers studies the causalities and effects on the relationship between inbound tourism(TOU) and the production amount of service industry in China, using the unit root test, the Granger causality test, the cointegration test, and VECM. we take their natural logarithm and define them as TOU and SGDP: these represent the distributed variable based the lagged values of the number of international tourists by continent and real production amount in service industry of China, respectively. The results of empirical study of this papers are as follows: Firstly, in the unit root test, we found that each time series was unstable one that has unit root. This result made me use 1st differenced data for this empirical study. Secondly, in the Granger casuality test, the study results show that there is unilateral casuality relation between DLSGDP-$DLTOU_i$ except DLSGDP-DLTOUL model for the same time, while no casuality relation between DLTOU-DLSGDP for all models of China. Thirdly, there is cointegration relation between all models for the period of 1980-2008.

• Progress in Medical Physics
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• v.7 no.1
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• pp.53-64
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• 1996

Purpose: The purposes of this paper are to develop a theoretical basis that the beam directions should be considered when the mechanical accuracy of teletherapy machine is evaluated by the star pattern test, to develop methods using asymmetric field in length to simulate beam direction for the case that beam direction does not appear on film. Method: In evaluating mechanical rotational accuracy of the gantry of teletherapy unit by the star pattern test, the direction of radiation beams was considered. A star pattern using some narrow beams was made. Density profiles at 10cm far from estimated gantry axis on the star pattern were measured using an optical densitometer. On each profile, one coordimate of a beam axis was determined. A pair of coordinates on a beam axis form an equation of the axis. Assume that a unit vector equation omitted is with same direction as radiation beam and a vector equation omitted is a vector directing to the beam axis from the estimated gantry axis. Then, a vector product equation omitted ${\times}$ equation omitted is an area vector of which the absolute value is equal to the distance from the estimated gantry axis to the beam axis. The coordinate of gantry axis was obtained by using least-square method for the area vectors relative to the average of whole area vectors. For the axis, the maximum of absolute value of area vectors would be an accuracy of the gantry rotation axis. For the evaluation of mechanical accuracies of collimator and couch axes for which beam direction could not be depicted on a star pattern test film, narrow beams asymmetric in field length was used to simulate beam direction. Result: For a star test pattern to evaluate the mechanical accuracy of rotational axes of a telectherapy machine, the result considering beam direction was different from that ignoring beam direction. For the evaluation of mechanical accuracies of collimator and couch axes by means of a star pattern test, narrow asymmetric beams could simulate beam direction. Conclusion: When a star pattern test is used to evaluate the mechanical accuracy of a teletherapy unit, beam direction must be considered or simulated, and quantitatively evaluated.

• Journal of the Korean Association of Geographic Information Studies
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• v.9 no.2
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• pp.227-238
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• 2006

Line density index(LDI) was developed to quantify a densely isothermal line rate as standard index in the ocean environment. Theoretical background on the LDI development process restricting index range 0 to 100 was described. And validation test was done for the LDI application condition that total line length is not greater than 1/10 of unit area. NOAA SST(Sea Surface Temperature) data were used for the experimental application of LDI in the South Sea of Korea. Using GIS, $0.1^{\circ}C$ isothermal lines were linearized as vector data form SST raster data, and unit area were built as polygon data. For the LDI calculation, spatial overlapping(line in polygon) was implemented. To analyze the effect of unit area size for the LDI distribution, two cases of unit area size were designed and descriptive statistics was calculated including performing normality test. The results showed no change of LDI's essential characteristics such as mean and normality except for the range of value, variance and standard deviation. Accordingly, it was found that complex structure of thermal front and even smaller scale of front width than unit area size could influence on the LDI distribution. Also, correlation analysis performed between LDI and difference of temperature(${\Delta}T^{\circ}C$), and horizontal thermal gradient(${\Delta}T^{\circ}C/km$) on the front was obtained from linear regression model. This obtained value was compared with the results from previous researches. Newly developed LDI can be used to compare the thermal front regions changing spatio-temporally in the ocean environment using absolute index value. It is considered to be significant to analyze the relationship between thermal front and marine environment or front and marine organisms in a quantitative approach described in this study.