• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.1D
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• pp.67-72
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• 2006

Temperature prediction in asphalt pavements is the one of most important factors for estimating the pavement response and predicting the pavement performance in the mechanistic-empirical pavement design. A study on temperature prediction procedure with variation of time and depth in asphalt pavements was conducted using field monitoring data. After selecting the temperature monitoring sections, the temperature sensors have been installed in different depths and the temperature data have been collected in every one hour. The developed pavement temperature prediction model was calibrated using field monitoring temperature data. The predicted temperatures were compared with measured temperatures at different seasons in selected sections. The results showed that the solar absorptivity and emissivity values in the fall is different from the values in other seasons. The predicted temperatures agree well with the measured temperatures at a wide range of temperatures. The temperature differences between each other fall in the range of ${\pm}3^{\circ}C$. It is also found that the regional characteristics did not affect the temperature prediction procedure.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.1A
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• pp.1-8
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• 2009

Stay cable is easily exposed to vibration induced rainy wind effects. There are some problems for not only unexpected vibration but also well-known vibration. An outbreak of displacement by the said effects brings damages such as over-tension of cables and barriers, fatigue of anchorages and dampers, and additional shear force variation of stiffening girders. This study suggests analytic methodology for dynamic tension variation of cables and shear force variation of stiffening girders. Additionally this study announces with dynamic problems for cable stayed bridge briefly. To realize this subject, we divide restoring force into chord component and normal component and then make up the differential equations which can satisfy physical phenomenon for each component. Finally we apply adequate functions such as sinusoidal and parabola in order to reduce these differential equations. Therefore we can meet with good results through a series of above process. As a remarkable result, CIP recommendations (2002) give inadequate solution with over 10% error. However it gives very good solution if parts of our study are reflected at the said recommendations. The fact means that CIP recommendations (2002) well-known as international standard of stay cables are not even concern about this subject yet. For verification of this study, F.E. analysis using E.C.C. with external forces was fulfilled, and the accuracy and conciseness of this study were shown.

• Journal of Service Research and Studies
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• v.14 no.2
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• pp.158-177
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• 2024

This paper proposes and tests a theoretical model of the relational link between a novel form of customer-perceived fairness for a reward design (distributive peer justice climate) and C2C helping intention via community identification and online C2C interaction (friend-, neighboring customer-, audience-interaction) qualities in a collective consumption context (MMORPG). To test hypotheses, we amassed survey data within a collective consumption context (massively multiplayer online role-playing games, MMORPGs). We used structural equation modeling in analyzing the survey data. The results reveal that user-perceived distributive peer justice climate for a reward design enhances their C2C helping intention via community identification and C2C interactions in MMORPG contexts. Collective consumption-type service managers should focus on promoting the user-perceived distributive peer justice climate for their reward system to enhance users' present C2C co-creation experience (community identification, C2C interaction) and future C2C co-creation behavior (helping intention). By adopting an intra-unit level distributive justice concept (customer-perceived distributive peer justice climate) to a reward design in a collective consumption context (MMORPGs), this study informed collective consumption-type service managers of the importance of its management.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.13 no.2
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• pp.95-109
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• 1993

In this study, the optimal configuration of arch structure has been tested by a decomposition technique. The object of this study is to provide the method of optimizing the shapes of both two hinged and fixed arches. The problem of optimal configuration of arch structures includes the interaction formulas, the working stress, and the buckling stress constraints on the assumption that arch ribs can be approximated by a finite number of straight members. On the first level, buckling loads are calculated from the relation of the stiffness matrix and the geometric stiffness matrix by using Rayleigh-Ritz method, and the number of the structural analyses can be decreased by approximating member forces through sensitivity analysis using the design space approach. The objective function is formulated as the total weight of the structures, and the constraints are derived by including the working stress, the buckling stress, and the side limit. On the second level, the nodal point coordinates of the arch structures are used as design variables and the objective function has been taken as the weight function. By treating the nodal point coordinates as design variable, the problem of optimization can be reduced to unconstrained optimal design problem which is easy to solve. Numerical comparisons with results which are obtained from numerical tests for several arch structures with various shapes and constraints show that convergence rate is very fast regardless of constraint types and configuration of arch structures. And the optimal configuration or the arch structures obtained in this study is almost the identical one from other results. The total weight could be decreased by 17.7%-91.7% when an optimal configuration is accomplished.

• Journal of the Korean Society of Hazard Mitigation
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• v.2 no.1 s.4
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• pp.135-141
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• 2002

Both non-linear damping values of the deep and shallow crustal materials and seismic source parameters are found from the observed near-field seismic ground motions at the South-eastern Korean Peninsula. The non-linear numerical algorithm applied in this study is Levenberg-Marquadet method. All the 25 sets of horizontal ground motions (east-west and north-south components at each seismic station) from 3 events (micro to macro scale) were used for the analysis of damping values and source parameters. The non-linear damping values of the deep and shallow crustal materials were found to be more similar to those of the region of the Western United States. The seismic source parameters found from this study also showed that the resultant stress drop values are relatively low compared to those of the Western United Sates. Consequently, comparisons of the various seismic parameters from this study and those of the United States Seismo-tectonic data suggest that the seismo-tectonic characteristics of the South eastern Korean Peninsula is more similar to those of the Western U.S.

• Progress in Medical Physics
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• v.26 no.3
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• pp.143-152
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• 2015

In this study, we aim to design the architecture of the kV imaging system for tumor tracking in the dual-head gantry system and analyze its accuracy by simulations. We established mathematical formulas and algorithms to track the tumor position with the two-pair kV imaging systems when they are in the non-orthogonal positions. The algorithms have been designed in the homogeneous coordinate framework and the position of the source and the detector coordinates are used to estimate the tumor position. 4D XCAT (4D extended cardiac-torso) software was used in the simulation to identify the influence of the angle between the two-pair kV imaging systems and the resolution of the detectors to the accuracy in the position estimation. A metal marker fiducial has been inserted in a numerical human phantom of XCAT and the kV projections were acquired at various angles and resolutions using CT projection software of the XCAT. As a result, a positional accuracy of less than about 1mm was achieved when the resolution of the detector is higher than 1.5 mm/pixel and the angle between the kV imaging systems is approximately between $90^{\circ}$ and $50^{\circ}$. When the resolution is lower than 1.5 mm/pixel, the positional errors were higher than 1mm and the error fluctuation by the angles was greater. The resolution of the detector was critical in the positional accuracy for the tumor tracking and determines the range for the acceptable angle range between the kV imaging systems. Also, we found that the positional accuracy analysis method using XCAT developed in this study is highly useful and will be a invaluable tool for further refined design of the kV imaging systems for tumor tracking systems.

• The Journal of Society for e-Business Studies
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• v.25 no.1
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• pp.135-176
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• 2020

This study is to investigate the factors affecting the usage intentions of 5G service between 5G service subscribers and non-subscribers based on the Integratively Extended Technology Acceptance Model in the initial B2C 5G service market. We designed the integratively extended technology acceptance model to find the more specific factors to affect the usage intentions by integrating the exogenous factors including the technical factors, the social factors, and the personal factors with the ETAM(Extended Technology Acceptance Model). Referring to the previous studies, we constructed the hypotheses of structural influence relationship from the exogenous factors to the dependent usage intentions factors through the mediating belief factors. We designed the 5G service usage intentions model based on these hypotheses and operational definitions of the factors. Using the analysis of SEM(Structural Equation Model), the proposed model and the hypotheses were empirically tested by the data collected from 245 subscribed respondents and 245 non-subscribed respondents. As a result, the perceived ease of use has an effect on the perceived usefulness and enjoyment, and the perceived usefulness/enjoyment and the personal innovativeness have positive effects on the usage intentions of both groups.

• Korean Journal of Agricultural Science
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• v.7 no.2
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• pp.131-144
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• 1980

The Linear Regression Model to extend the monthly runoff data in the short-recorded river was proposed by the author in 1979. Here in this study generalization precedure is made to apply that model to any given river basin and to any given station. Lengthier monthly runoff data generated by this generalized model would be useful for water resources assessment and waterworks planning. The results are as follows. 1. This Linear Regression Model which is a transformed water-balance equation attempts to represent the physical properties of the parameters and the time and space varient system in catchment response lumpedly, qualitatively and deductively through the regression coefficients as component grey box, whereas deterministic model deals the foregoings distributedly, quantitatively and inductively through all the integrated processes in the catchment response. This Linear Regression Model would be termed "Statistically deterministic model". 2. Linear regression equations are obtained at four hydrostation in Geum-river basin. Significance test of equations is carried out according to the statistical criterion and shows "Highly" It is recognized th at the regression coefficients of each parameter vary regularly with catchment area increase. Those are: The larger the catchment area, the bigger the loss of precipitation due to interception and detention storage in crease. The larger the catchment area, the bigger the release of baseflow due to catchment slope decrease and storage capacity increase. The larger the catchment area, the bigger the loss of evapotranspiration due to more naked coverage and soil properties. These facts coincide well with hydrological commonsenses. 3. Generalized diagram of regression coefficients is made to follow those commonsenses. By this diagram, Linear Regression Model would be set up for a given river basin and for a given station (Fig.10).

• Journal of dental hygiene science
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• v.14 no.1
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• pp.67-73
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• 2014

This study analyzed 548 pieces of these, which were reported in the Journal of Dental Hygiene Science of having been published from 2001 to Vol. 12, No. 6 in 2012. In conclusion, as for analysis of research design, first, it was the largest in cross sectional research. Second, the research subjects of survey theses were higher in order of dental hygienist and dental hygiene student. Third, number of thesis authors was the largest in order of two persons and three persons. Fourth, statistical method was in order of descriptive statistics, t-test, and ANOVA. Research theme was in order of dental health behavioral science and clinical dental hygiene. Fifth, as for research-expense benefit, only 17.7% was supported research funds. As a result of this study, there should be a research on thesis of diverse designs in the future. There is a need of being performed actively a research on alienated classer or special subjects as well as a research on activity related to dental hygiene.

• Korean Chemical Engineering Research
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• v.45 no.1
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• pp.57-66
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• 2007

Natural gases generally consist of mainly $^{12}C$ and about 1.1% of $^{13}C$. It is well known that a stable carbon isotope, $^{13}C$, has been widely used for the applications of medical, pharmaceutical, and agricultural tracers. As a result, the development of the separation and concentrating technology of $^{13}C$ can cause of high value-added products and the possibility of the generation of new carbon materials, In general, there are two kinds of approaches to obtain a stable $^{13}C$ isotope by the separation of cryogenic distillation. One is to obtain a concentrated $^{13}CH_4$ isotope from natural gas. Another approach is to get concentrated $^{13}CO$ by distillation followed by a chemical reaction of $CH_4$ and $H_2O$. In this study, rigorous process simulations of the cryogenic distillation have been performed and analyzed for the concentrated separation of $^{13}C$ isotopes from LNG and NG by using commercial process simulator. Due to the very small differences of relative volatilities and separabilities of $^{12}C$ and $^{13}C$, the process design and operation of effective separation and concentration of $^{13}C$ need special strategies and feasibility studies. Utilization of vapor pressure data to acentric factor in SRK equation of state and optimized process conditions have been able to predict for the effective of the separation yield and concentration of $^{13}C$ for the cryogenic distillation. The various operation strategies for both batch and continuous cryogenic distillation are also studied and suggested for the basic design of the process. Development of this study can provide a tool for the effective design and operation of the cryogenic separation of $^{13}C$.