• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.8
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• pp.3597-3609
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• 2012

Purpose: This study was done to develop the multidimensional scale of addictive behavior for adolescents. Methods: The process involved construction of a conceptual framework, initial items, verification of content validity, selection of secondary items, and extraction of final items. The participants were 636 adolescents in six middle schools and four high schools. Results: Seventy items were selected for the final scale, and categorized 8 factors explaining 56.5% of total variance. The factors were labeled as game addictive behavior, shopping addictive behavior, mobile phone addictive behavior, nicotine addictive behavior, television addictive behavior, gambling addictive behavior, alcohol addictive behavior, and internet addictive behavior. The scores for the scale were significantly correlated with addictive personality and self-control. Cronbach's alpha coefficient for the 70 items was .94. Scale scores identified adolescents as addictive behavior group, risk group, and average group. Conclusion: The above findings indicate that the multidimensional scale of addictive behavior for adolescents has good validity and reliability when used with adolescents. More importantly, it provides the first step toward developing a addiction prevention program. Additionally the scales provide an education or guideline, and proper physical and mental health management of youth in research and practice for the promotion of education.

• Journal of Information Management
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• v.36 no.3
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• pp.183-193
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• 2005

Korean Academy of Medical Sciences began developing Korean Medical Citaton Index(KoMCI) database in 2002, and has announced the impact factors of Korean medical journals published since 2000. In July 2005, Korea Research Foundation also announced the KCI impact factor of journals covering all subject areas for the 2003 and 2004. We compared the impact factor(IF), impact factor excluding self-citation(ZIF), and self-citation impact factor(SIF) of KoMCI 2004 and KCI 2004 in order to disclose why there is such a great difference in the values of impact factors between two databases. Out of 72 medical journals in both database, 59 journals were compared after excluding the missing data in KCI. Mean IF of KoMCI 2004 was 0.2 and that of KCI 2004 was 0.03(p=0.0000). Mean ZIF of KoMCI was 0.06 and that of KCI was 0.01(p=0.000). Mean SIF of KoMCI was 0.139 and that of KCI was 0.02(p=0.0000). We presumed that the major difference in the impact factor values was originated from the fact that KCI does not control the authority of journal names cited in the references. We strongly recommend that it is necessary to control the authority especially if Korea Research Foundation wants to ensure the validity and reliability of KCI data in the evaluation of korean journals.

• Korean Journal of Remote Sensing
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• v.21 no.4
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• pp.287-302
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• 2005

Digital Elevation Models (DEMs) were generated by ERS-l/2 and JERS-1 SAR interferometry in Daejon area, Korea. The quality of the DEM's was evaluated by the Ground Control Points (GCPs) in city area where GCPs were determined by GPS surveys, while in the mountain area with no GCPs, a 1:25,000 digital map was used. In order to minimize errors due to the inaccurate satellite orbit information and the phase unwrapping procedure, a Differential InSAR (DInSAR) was implemented in addition to the traditional InSAR analysis for DEM generation. In addition, DEMs from GTOPO30, SRTM-3, and 1:25,000 digital map were used for assessment the resolution of the DEM generated from DInSAR. 5-6 meters of elevation errors were found in the flat area regardless of the usage and the resolution of DEM, as a result of InSAR analyzing with a pair of ERS tandem and 6 pairs of JERS-1 interferograms. In the mountain area, however, DInSAR with DEMs from SRTM-3 and the digital map was found to be very effective to reduce errors due to phase unwrapping procedure. Also errors due to low signal-to-noise ratio of radar images and atmospheric effect were attenuated in the DEMs generated from the stacking of 6 pairs of JERS-1. SAR interferometry with multiple pairs of SAR interferogram with low resolution DEM can be effectively used to enhance the resolution of DEM in terms of data processing time and cost.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.10
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• pp.125-132
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• 2019

Because the water exposed to shock waves caused by an underwater explosion cannot withstand the appreciable tension induced by the change in both pressure and velocity, the surrounding water is cavitated. This cavitating water changes the transferring circumstance of the shock loading. Three phenomena contribute to hull-plate damage; initial shock loading and its interaction with the hull plate, local cavitation, and local cavitation closure then shock reloading. Because the main concern of this paper is local cavitation due to a near-field underwater explosion, the water surface and the waves reflected from the sea bottom were not considered. A set of governing equations for the structure and the fluid were derived. A simple one-dimensional infinite plate problem was considered to verify this uncoupled solution approach compared with the analytic solution, which is well known in this area of interest. The uncoupled solution approach herein would be useful for obtaining a relatively high level of accuracy despite its simplicity and high computational efficiency compared to the conventional coupled method. This paper will help improve the understanding of fluid-structure interaction phenomena and provide a schematic explanation of the practical problem.

• Korean Journal of Clinical Laboratory Science
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• v.51 no.1
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• pp.93-104
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• 2019

This study examined the relationship between the number of medical technologists and the medical test count. Data was obtained from 441 medical technologists in a hospital through a self-reported questionnaire. The Pearson correlation test, student's t-test, ANOVA or descriptive statistics were performed for data analysis. The distribution of medical technologist according to the size of hospitals was small 5.8, medium 14.9, large 25.8, and super 45.4. The analysis demonstrated a relationship between the number of medical technologists and the number of medical tests in the field, number of clinical tests per MT, and number of optimal medical test per MT according to the hospital size (P<0.001). The average time for quality control by the department at a higher hospital was less than two hours. In terms of the satisfaction of salary, work environment, test accomplishment, and welfare service, the dissatisfaction of medical technologists in small and medium hospitals was higher than those in large and super hospitals. Overall, a focus on intensifying systemic supplementation and improving the condition of medical technologists is needed to provide reliable data for medical examinations in medical areas.

• Journal of Food Hygiene and Safety
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• v.34 no.3
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• pp.309-315
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• 2019

To enumerate Staphylococcus aureus in food, Baird-Parker Agar (BPA) is usually used in the conventional method, However it requires time and space for the preparation and plating, and incubation. Thus, use of the $3M^{TM}$ $Petrifilm^{TM}$ Staph Express Count Plate (STX Petrifilm) might be appropriate to solve these challenging problems. The purpose of this study was to compare the efficiency of STX Petrifilm with BPA for enumeration of S. aureus in various foods. A mixture of S. aureus strains ATCC29213, ATCC25923, and ATCC13565 was inoculated on marinated pork chop, beef (chuck tender), dried filefish, semi-dried squid, rice cake, and Japchae (stir-fried glass noodles) at 2, 3, 5, and 7 Log CFU/g. S. aureus cell counts were enumerated by spread-plating on STX Petrifilm and BPA after 0 and 24 hours at $4^{\circ}C$ (marinated pork chop, beef, semi-dried squid, and stir-fried glass noodles) and $25^{\circ}C$ (dried filefish and rice cake). Recovery of STX Petrifilm for S. aureus from various food samples was compared with BPA, and the results showed that there were no significant differences between two selective media in all cases. The results indicated that STX Petrifilm had enough efficiency to recover S. aureus from various foods as well as saving time and space.

• Journal of Internet Computing and Services
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• v.19 no.6
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• pp.21-29
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• 2018

In the era of the 4-th industrial revolution, the concept of smart factory is emerging. There are efforts to predict the occurrences of facility errors which have negative effects on the utilization and productivity by using data analysis. Data composed of the situation of a facility error and the type of the error, called the facility error log, is required for the prediction. However, in many manufacturing companies, the types of facility error are not precisely defined and categorized. The worker who operates the facilities writes the type of facility error in the form with unstructured text based on his or her empirical judgement. That makes it impossible to analyze data. Therefore, this paper proposes a framework for constructing a phrase network to support the identification and classification of facility error types by using facility error logs written by operators. Specifically, phrase indicating the types are extracted from text data by using dictionary which classifies terms by their usage. Then, a phrase network is constructed by calculating the similarity between the extracted phrase. The performance of the proposed method was evaluated by using real-world facility error logs. It is expected that the proposed method will contribute to the accurate identification of error types and to the prediction of facility errors.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.33 no.3
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• pp.122-130
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• 2021

A wind-speed estimation at the arbitrary elevations is key component for the design of the offshore wind energy structures and the computation of the wind-wave generation. However, the wind-speed estimation of the target elevation has been carried out by using the typical functions and their typical parameters, e.g., power and logarithmic functions because the available wind speed data is limited to the specific elevation, such as 2~3m, 10 m, and so on. In this study, the parameters of the vertical profile functions are estimated with optimal and analyzed the parameter ranges using the HeMOSU-1 platform wind data monitored at the eight different locations. The results show that the mean value of the exponent of the power function is 0.1, which is significantly lower than the typically recommended value, 0.14. The values of the exponent, the friction velocity, and the roughness parameters are in the ranges 0.0~0.3, 0~10 (m/s), and 0.0~1.0 (m), respectively. The parameter ranges differ from the typical ranges because the atmospheric stability condition is assumed as the neutral condition. To improve the estimation accuracy, the atmospheric condition should be considered, and a more general (non-linear) vertical profile functions should be introduced to fit the diverse profile patterns and parameters.

• Geophysics and Geophysical Exploration
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• v.26 no.3
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• pp.114-125
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• 2023

The physics-informed neural network (PINN) has been proposed to overcome the limitations of various numerical methods used to solve partial differential equations (PDEs) and the drawbacks of purely data-driven machine learning. The PINN directly applies PDEs to the construction of the loss function, introducing physical constraints to machine learning training. This technique can also be applied to wave equation modeling. However, to solve the wave equation using the PINN, second-order differentiations with respect to input data must be performed during neural network training, and the resulting wavefields contain complex dynamical phenomena, requiring careful strategies. This tutorial elucidates the fundamental concepts of the PINN and discusses considerations for wave equation modeling using the PINN approach. These considerations include spatial coordinate normalization, the selection of activation functions, and strategies for incorporating physics loss. Our experimental results demonstrated that normalizing the spatial coordinates of the training data leads to a more accurate reflection of initial conditions in neural network training for wave equation modeling. Furthermore, the characteristics of various functions were compared to select an appropriate activation function for wavefield prediction using neural networks. These comparisons focused on their differentiation with respect to input data and their convergence properties. Finally, the results of two scenarios for incorporating physics loss into the loss function during neural network training were compared. Through numerical experiments, a curriculum-based learning strategy, applying physics loss after the initial training steps, was more effective than utilizing physics loss from the early training steps. In addition, the effectiveness of the PINN technique was confirmed by comparing these results with those of training without any use of physics loss.

• Journal of the Korean Geotechnical Society
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• v.22 no.9
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• pp.45-59
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• 2006

The successful performance of any numerical geotechnical simulation depends on the accuracy and efficiency of the numerical implementation of constitutive model used to simulate the stress-strain (constitutive) response of the soil. The corner stone of the numerical implementation of constitutive models is the numerical integration of the incremental form of soil-plasticity constitutive equations over a discrete sequence of time steps. In this paper a well known two-surface soil plasticity model is implemented using a generalized implicit return mapping algorithm to arbitrary convex yield surfaces referred to as the Closest-Point-Projection method (CPPM). The two-surface model describes the nonlinear behavior of coarse-grained materials by incorporating a bounding surface concept together with isotropic and kinematic hardening as well as fabric formulation to account for the effect of fabric formation on the unloading response. In the course of investigating the performance of the CPPM integration method, it is proven that the algorithm is an accurate, robust, and efficient integration technique useful in finite element contexts. It is also shown that the algorithm produces a consistent tangent operator $\frac{d\sigma}{d\varepsilon}$ during the iterative process with quadratic convergence rate of the global iteration process.