• Journal of Digital Convergence
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• v.18 no.11
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• pp.129-136
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• 2020

The advantages of Blockchain present the necessity of Blockchain in various fields. However, there are several disadvantages to Blockchain. Among them, the uncle block problem is one of the problems that can greatly hinder the value and utilization of Blockchain. Although the value of Blockchain may be degraded by the uncle block problem, previous studies did not pay much attention to research on uncle block. Therefore, the purpose of this study attempts to predict the occurrence of uncle block in order to predict and prepare for the uncle block problem of Blockchain. This study verifies the validity of introducing new attributes and ensemble analysis techniques for accurate prediction of uncle block occurrence. As a research method, voting, bagging, and stacking ensemble analysis techniques were employed for Ethereum's uncle block where the uncle block problem actually occurs. We used Blockchain information of Ethereum and Bitcoin as analysis data. As a result of the study, we found that the best prediction result was presented when voting and stacking ensemble techniques were applied using only Ethereum Blockchain information. The result of this study contributes to more accurately predict the occurrence of uncle block and prepare for the uncle block problem of Blockchain.

• Journal of the Korean Geotechnical Society
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• v.20 no.7
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• pp.69-78
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• 2004

In this study, the back analysis program was developed by applying the genetic algorithm, one of artificial intelligence fields, to the direct method. The optimization process which has influence on the efficiency of the direct method was modulated with genetic algorithm. On conditions that the displacement computed by forward analysis for a certain rock mass model was the same as the displacement measured at the tunnel section, back analysis was executed to verify the validity of the program. Usefulness of the program was confirmed by comparing relative errors calculated by back analysis, which is carried out under the same rock mass conditions as analysis model of Gens et at (1987), one of back analysis case in the past. We estimated the total displacement occurring by tunnelling with the crown settlement and convergence measured at the working faces in three tunnel sites of Kyungbu Express railway. Those data measured at the working face are used for back analysis as the input data after confidence test. As the results of the back analysis, we comprehended the tendency of tunnel behaviors with comparing the respective deformation characteristics obtained by the measurement at the working face and by back analysis. Also the usefulness and applicability of the back analysis program developed in this study were verified.

• Korean Journal of Adult Nursing
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• v.12 no.4
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• pp.741-757
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• 2000

This study was undertaken to develop an instrument to be used for measuring the concept of quality of life of Korean patients with cancer multidimensionary and correctly. It can contribute in holistic nursing care for Korean cancer patients and also provide and validate basic data to help oncology nurses measure the outcome of nursing intervention correctly. To develop this instrument, the researchers first estabilished a conceptual framework based on the results of qualitative data analysis and indepth interview method Development of the scale was conducted using a method in which 31 items were assessed by subjects' self report using linear analogue scales. The subjects were 79 D.M. patients, 103 patients with acute illness, and 91 cancer patients residing in Busan, Korea. Data were collected during the period from July, 24 to August 14, 2000. This instrument consisted of 31 items with a self report scale. This instrument covered 4 dimensions of cancer patients : 1) physical wellbeing 2) psychological wellbeing 3) social wellbeing and 4)spiritual wellbeing. Each item had a possible score of 10. The reliability of the scale was tested with Cronbach's alpha. Validity was evaluated by examining the relationships of this scale, Youn's Quality of Life Questionnare scores and the Simple Quality of Life scale. Two separate runs of multiple regression were used to predict scores on the Simple Quality of Life measurement. Further validation was obtained by examining the correlation between the instrument subscores and Youn's Quality of Life measurement subscore for convergence of this scale. Examination of the discriminant. power of the instrument was done using ANOVA test. The results are summarized as follows: 1. The reliability of the instrument for the quality of life was 0.8321(Cronbach's alpha.), physical wellbeing dimension 0.6343, psychological wellbeing dimension 0.6501, spiritual wellbeing dimension 0.5883. 2. This instrument had a high correlation with Youn's Quality of Life measurement(r= 0.636) in cancer patients, whereas it had a low correlation with Simple Quality of Life measurement(r=0.455) in cancer patients. In the D.M. patients, the instrument correlated with both the Youn's Quality of Life measurement and Simple Quality of life measurement(r=0.313, r= 0.407) and in the acute stage patients, the instrument had no correlation. 3. Multiple regression of individual items on the Simple Quality of Life scores accounted for 56.8% of the variance in the Simple Quality of Life measurement, whereas, Youn's Quality of Life measurement scores accounts for 31.7%. 4. The correlations collected from the three group had the same patterns of variations but especially the instrument developed in this study had higher disciminant power than that of Youn's Quality of Life Measurement.

• Journal of Digital Convergence
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• v.15 no.5
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• pp.99-106
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• 2017

The purpose of this study is to analyze the relationship between tourist 's intention to use smartphone and the preceding factors through the questionnaire. For achieving this research purpose, this study surveyed the tourists who use smartphone to investigate the influence of interactivity such as two-way communication and synchronicity as hypotheses on the influence of flow, and the effect of attitude factors on continuous intention to use was analyzed by research model. In this study, a partial least squares based structural equation (PLS-SEM) method was applied to verify the hypothesis of the proposed research model. Finally, the validity of the proposed research model was confirmed through confirmatory factor analysis and hypothesis testing. Therefore, the results of this study show that interactivity and flow are influential for the reuse of users in utilizing information by using smartphone, and it affects the attitude of users in developing smart tourism system in the future. The results of this study can be utilized as basic data related to the acquisition of information by smartphone of tourists in the future development of smart tourism system.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2000.11b
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• pp.146-153
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• 2000

The rubber crawler system for farm machine is composed of driving units such as track rollers, driving sprockets and rubber crawlers. Vibration characteristics of the rubber crawler system varies by driving speed, center of gravity, mass□moment of inertial□location arrangement of track rollers and dynamic parameters such as dynamic spring constant (k) and viscous damping coefficient (c) of a rubber crawler. In general, vibration of the rubber crawler system occurs by reason for mechanical interaction between the rubber crawler and track rollers. Because the dynamic spring constant and viscous damping coefficient vary periodically by mechanical characteristics(deformation characteristics) of the rubber crawler when track rollers drive on the between lugs of the rubber crawler. Therefore, both dynamic parameters k and c were expressed as Fourier series by authors through the shaking test of the rubber crawler and further, vibration characteristics of the rubber crawler system could be simulated analytically. However, actual values of dynamic parameters k and c are different from those obtained by the shaking test because dynamic characteristics of the rubber crawler vary by the effect of variable tension and driving resistance of track rollers. So, actual values of k and c should be identified in the condition of actual driving test. In this study, dynamic parameters such as k and c of the rubber crawler system, which are expressed as Fourier series, were identified using the Gauss-Newton Method. Therefore, validity of identified parameters k and c was discussed through the simulation using experimental data of actual driving test. As a result, in the Fourier series of dynamic parameters of spring constant k and viscous damping coefficient c, excellent parameter convergence and simulation were observed using the Fourier series' zero order and first term of the dynamic model. Furthermore, it was clarified that identification for model parameters which are fitted to actual dynamic motion (vibration) wave of the crawler system was possible by using the time series data observed in vertical and pitching motion of the crawler system.

• Korean Journal of Environment and Ecology
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• v.34 no.2
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• pp.179-187
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• 2020

The study was conducted on Godeoksan, Gangdong-gu, Seoul, for the study of elderly people's park use and satisfaction. For the analysis, frequency analysis was performed on all items, and reliability analysis was performed to check the validity of the items. Factor analysis was used to identify items that have a significant effect on the customer's satisfaction. Multiple regression analysis was performed using the derived factors. As a result of factor analysis, it was found that the factors affecting satisfaction were composed of three factors and 69.50% of the total variance was explained. The KMO value, which means the sample fit between items, was analyzed as .756. Factors were classified into usage aspect, ecological aspect, and amenityt aspect by reflecting the characteristics of the item. As a result of the multiple regression analysis through the derived factors, the multiple regression equation for the elderly's park use satisfaction was analyzed to be Y = 3.678 + 0.202X₁ + 0.125X₂ + 0.236X₃. In this study, there are limitations in conducting a questionnaire survey for the elderly who lack professional knowledge. In the future, evaluation studies should be conducted for the elderly with specialized knowledge, and it is judged that a comparative study of ecological, utilization, and climatic aspects by age is necessary.

• Journal of Digital Convergence
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• v.8 no.1
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• pp.55-69
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• 2010

This thesis looks closely at the moderating effect of individual variables while we analyzed how corporate's ethics policies have influence on his ethical decision-making behaviors. The subjects of the research were full-time employees (n=211) in the Seoul metropolitan region. The research model was substantiated through statistical analysis of credibility and validity, correlation, variance, and moderated regression analysis (MRA). This study found that within an organization with a code of ethics, the level of enforcement of the code and the level of employee awareness of core values sought by the company determined the level of influence of the code on ethical decision making. In other words, internal factors exerted a greater influence than external evaluation of a corporation's ethical decision making practices and therefore, it is necessary for decision-making practices to be transparent and recognized by the members within an organization. The study also found that the employee's awareness about the long-term visions of the company at a higher level and the employees who have a locus of control to their members internally acted as independent variables as well as control variables on the ethical decision-making. In addition, there were great differences in the level of ethical decision-making among the variables used as controls, which means these differences were related to the individual variables. Accordingly, in order to get ethical decision-making practices at a higher level, a education & training program will be designed and implemented variously as considering on the particular characteristics of the control variables we used in this study.

• Journal of Digital Convergence
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• v.12 no.5
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• pp.403-413
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• 2014

This study is to select educational films suitable for enhancing creativity and personality in order to develop educational contents aimed at pre-service early childhood teacher. First, three film critics based on sub-elements of ego-identity selected final 59 films. Next, three education experts classified the 59 films into small groups based on components each for creativity and personality. As a result, first, films classified according to pre-service early childhood teacher' sub-elements of ego-identity, educational components for creativity, and educational components for personality were 8 in job, 7 in religion, 6 in politics, 7 in philosophical life style, 8 in friendship, 8 in relationship, 7 in gender role, and 8 in leisure activity. Second, verifying suitability of film critics and education experts using Delphi method in order to select educational films to enhance pre-service early childhood teacher' creativity and personality based on films was effective in increasing validity of the results of this research.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.15 no.3
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• pp.491-499
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• 2002

A p-version finite element model based on degenerate shell element is proposed tot the analysis of orthotropic laminated plates. In the nonlinear formulation of the model, the total Lagrangian formulation is adopted with large deflection and moderate rotation being accounted tot in the sense of yon Karman hypothesis. The material model is based on the Huber-Mises yield criterion and Prandtl-Reuss flow rule in accordance with the theory of strain hardening yield function, which is generalized lot anisotropic materials by introducing the parameters of anisotropy. The model is also based on extension of equivalent-single layer laminate theory(ESL theory) with shear deformation, leading to continuous shear strain at the interface of two layers. The integrals of Legendre polynomials are used for shape functions with p-level varying from 1 to 10. Gauss-Lobatto numerical quadrature is used to calculate the stresses at the nodal points instead of Gauss points. The validity of the proposed P-version finite element model is demonstrated through several comparative points of iew in terms of ultimate load, convergence characteristics, nonlinear effect, and shape of plastic tone.

• Journal of Korean Tunnelling and Underground Space Association
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• v.22 no.2
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• pp.155-170
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• 2020

In this paper, a risk management system applicable to NATM tunneling projects is proposed. After investigating case histories in NATM tunnel collapse, this paper analyzes the potential risk factors and their corresponding risk events during NATM tunnel construction. The risk factors are categorized into three groups: geological, design and construction risk factors. The risk events are also categorized into four types: excessive deformation, excessive deformation with subsidence, collapse inside tunnels, and collapse inside tunnels with subsidence. The paper identifies risk scenarios in consideration of the risk factors and proposes a risk analysis/evaluation method for the NATM tunnel risk scenarios. Based on the evaluation results, the optimal mitigation measure to handle the risk events is suggested. In order to effectively facilitate a series of risk management processes, it is necessary to develop a risk register and a management ledger for risk mitigation measures that are customized to NATM tunnels. Lastly, the risk management for an actual NATM tunnel construction site is performed to verify the validity of the proposed system.