• Journal of Convergence for Information Technology
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• v.9 no.5
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• pp.7-13
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• 2019

Role-based access or attribute-based access control in cloud environment or big data environment need requires a suitable mathematical structure to represent a hierarchical model. This paper define the notion of multipliers and simple multipliers of lattice implication algebras that can implement a hierarchical model of role-based or attribute-based access control, and prove every multiplier is simple multiplier. Also we research the relationship between multipliers and homomorphisms of a lattice implication algebra L, and prove that the lattice [0, u] is isomorphic to a lattice $[u^{\prime},1]$ for each $u{\in}L$ and that L is isomorphic to $[u,1]{\times}[u^{\prime},1]$ as lattice implication algebras for each $u{\in}L$ satisfying $u{\vee}u^{\prime}=1$.

• Journal of Convergence for Information Technology
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• v.11 no.9
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• pp.84-93
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• 2021

The purpose of this study is to analyze whether the spread of COVID-19 infectious diseases acts as a fear to investors and affects the direction and volatility of stock returns. The investor fear index was proposed using the domestic confirmed patient information of COVID-19, and the influence on stock prices was empirically analyzed. The direction and volatility models of stock prices used the Granger causality and GARCH models, respectively. The results of empirical analysis using the KOSPI index from February 20, 2020 to June 30, 2021 are as follows: First, the COVID-19 fear index showed causality to future stock prices. Second, the COVID-19 fear index has a negative effect on the volatility of KOSPI index returns. In future studies, it is necessary to document the cause by using individual business performance and stock price instead of the stock index.

• The Journal of Advanced Prosthodontics
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• v.12 no.6
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• pp.361-368
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• 2020

PURPOSE. The present study aimed to evaluate the accuracy of a desktop scanner and intraoral scanners based on the volumetric dimensions of a complete arch. MATERIALS AND METHODS. Seven reference models were fabricated based on the volumetric dimensions of complete arch (70%, 80%, 90%, 100%, 110%, 120%, and 130%). The reference models were digitized using an industrial scanner (Solutionix C500; MEDIT) for the fabrication of a computer-aided design (CAD) reference model (CRM). The reference models were digitized using three intraoral scanners (CS3600, Trios3, and i500) and one desktop scanner (E1) to fabricate a CAD test model (CTM). CRM and CTM were then superimposed using inspection software, and 3D analysis was conducted. For statistical analysis, one-way analysis of variance was used to verify the difference in accuracy based on the volumetric dimensions of the complete arch and the accuracy based on the scanners, and the differences among the groups were analyzed using the Tukey HSD test as a post-hoc test (α=.05). RESULTS. The three different scanners showed a significant difference in accuracy based on the volumetric dimensions of the complete arch (P<.05), but the desktop scanner did not show a significant difference in accuracy based on the volumetric dimensions of the complete arch (P=.808). CONCLUSION. The accuracy of the intraoral scanners was dependent on the volumetric dimensions of the complete arch, but the volumetric dimensions of the complete arch had no effect on the accuracy of the desktop scanner. Additionally, depending on the type of intraoral scanners, the accuracy differed according to the volumetric dimensions of the complete arch.

• Journal of Convergence for Information Technology
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• v.11 no.2
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• pp.82-89
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• 2021

The objective of this study is to propose a new Glide Path that dynamically adjusts the risky asset inclusion ratio of the Target Date Fund by simultaneously considering the market's forecast volatility as well as the time of investor retirement, and to compare the investment performance with the traditional Target Date Fund. Forecasts of market volatility utilize historical volatility, time series model GARCH volatility, and the volatility index VKOSPI. The investment performance of the new dynamic Glide Path, which considers stock market volatility has been shown to be excellent during the analysis period from 2003 to 2020. In all three volatility prediction models, Sharpe Ratio, an investment performance indicator, is improved with higher returns and lower risks than traditional static Glide Path, which considers only retirement date. The empirical results of this study present the potential for the utilization of the suggested Glide Path in the Target Date Fund management industry as well as retirees.

• Journal of Convergence for Information Technology
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• v.11 no.6
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• pp.139-145
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• 2021

This study was conducted to find out the effect of job-crafting of social workers at community children's centers on the satisfaction of children. This study used a multi-level analysis model that calculated the child factor (level 1) and the social worker factor (level 2) by utilizing the responses of 31 social workers and 216 children used at 31 community children's centers. The main research results are as follows: First, it was found that 34.3% of the total variation in child satisfaction was due to differences by community children's centers. Second, it was found that the number of hours used per day in the child factor (level 1), and gender, age, and job-crafting in the life worker factor (level 2) affect the satisfaction of children. Based on these results, measures to improve the satisfaction level of children using community children's centers were discussed.

• Journal of Convergence for Information Technology
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• v.10 no.12
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• pp.91-99
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• 2020

The aim of this study to assess the effect of information security policy awareness, information security involvement, compliance behavioral intention on information security behavior The research method is composed of a cross-sectional design of reward and fairness. This paper focuses on the process of organizational policy on the information security compliance intention in the individual decision-making process. As a result, the reward had a significant effect on compliance behavioral intention, and it was found that influence of the psychological reward-based condition was greater than the material reward-based condition. The fairness had a significant effect on information security policy awareness, information security involvement, information security behavior, and it was found that influence of the equity-based condition was greater than the equality-based condition. The exploration model was verified as a multiple mediation model. In addition, the discussion presented the necessary research direction from the perspective of synergy by the cultural environment of individuals and organizations.

• Journal of Convergence for Information Technology
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• v.11 no.3
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• pp.7-13
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• 2021

This study develops an artificial intelligence prediction system for Fine particulate Matter(PM2.5) based on the deep learning algorithm GAN model. The experimental data are closely related to the changes in temperature, humidity, wind speed, and atmospheric pressure generated by the time series axis and the concentration of air pollutants such as SO2, CO, O3, NO2, and PM10. Due to the characteristics of the data, since the concentration at the current time is affected by the concentration at the previous time, a predictive model for recursive supervised learning was applied. For comparative analysis of the accuracy of the existing models, CNN and LSTM, the difference between observation value and prediction value was analyzed and visualized. As a result of performance analysis, it was confirmed that the proposed GAN improved to 15.8%, 10.9%, and 5.5% in the evaluation items RMSE, MAPE, and IOA compared to LSTM, respectively.

• Journal of Ginseng Research
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• v.45 no.2
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• pp.236-245
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• 2021

Background: Red ginseng (RG) extract, especially ginsenoside Rg1 and Rb1 fractions has been reported to have antithrombotic activities. However, gastric instability and low intestinal permeability are considered to be obstacles to its oral administration. We hypothesized that stability, permeability, and activities of RG might be improved by encapsulation within nanoparticles (NPs) prepared with antithrombotic coating materials. Methods: RG-loaded chitosan (CS) NPs (PF-NPs) were prepared by complex ionic gelation with the antithrombotic wall materials, polyglutamic acid (PGA), and fucoidan (Fu). The concentrations of PGA (mg/mL, X₁) and Fu (mg/mL, X₂) were optimized for the smallest particle size by response surface methodology. Antithrombotic activities of RG and PF-NPs were analyzed using ex vivo and in vivo antiplatelet activities, in vivo carrageenan-induced mouse tail, and arteriovenous shunt rat thrombosis models. Results: In accordance with a quadratic regression model, the smallest PF-NPs (286 ± 36.6 nm) were fabricated at 0.628 mg/mL PGA and 0.081 mg/mL Fu. The inhibitory activities of RG on ex vivo and in vivo platelet aggregation and thrombosis in in vivo arteriovenous shunt significantly (p < 0.05) increased to approximately 66.82%, 35.42%, and 38.95%, respectively, by encapsulation within PF-NPs. For an in vivo carrageenan-induced mouse tail thrombosis model, though RG had a weaker inhibitory effect, PF-NPs reduced thrombus significantly due to the presence of PGA and Fu. Conclusion: PF-NPs contributed to improve the activities of RG not only by nanoencapsulation but also by antithrombotic coating materials. Therefore, PG-NPs can be suggested as an efficient delivery system for oral administration of RG.

• Journal of Convergence for Information Technology
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• v.12 no.5
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• pp.100-106
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• 2022

A longitudinal study refers to a research method based on longitudinal data repeatedly measured on the same object. Most of the longitudinal analysis methods are suitable for prediction or inference, and are often not suitable for use in exploratory study. In this study, an exploratory method to analyze longitudinal data is presented, which is to find the longitudinal trajectory after determining the best number of clusters by clustering longitudinal data using self-organizing map technique. The proposed methodology was applied to the longitudinal data of the Employment Information Service, and a total of 2,610 samples were analyzed. As a result of applying the methodology to the actual data applied, time-series clustering results were obtained for each panel. This indicates that it is more effective to cluster longitudinal data in advance and perform multilevel longitudinal analysis.

• Journal of Convergence for Information Technology
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• v.12 no.2
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• pp.142-148
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• 2022

In this paper, the weight reduction design of the yaw gearbox for wind turbine was performed through the finite element analysis method, and the stability was checked by performing the critical speed analysis. The weight reduction product can improve engine efficiency, save parts materials, and earn economic benefits. The yaw gearbox is lightweighted with the goal of achieving a safety rate of 1.3 or higher for wind turbine as indicated by IEC61400-1. In order to reduce the weight of the carrier, a topology optimization method was performed. The safety factor was verified by performing finite element analysis on the carrier. In addition, the housing and carrier were modeled using the finite element method, and the gear train was modeled using MASTA. For the yaw gearbox, the housing and carrier FE model and the gear train model were connected by the partial structural synthesis method to perform the rotational vibration analysis. Vibration excitation sources are mass unbalance and gear mesh frrequemcy, and as a result of the critical speed analysis, it was found that there was no resonance within the operating speed range.