• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.35 no.1
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• pp.31-39
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• 2017

The goal of this study was to efficiently analyze the relationships of the number of thefts with related factors, considering the spatial patterns of theft crimes. Theft crime data for a 5-year period (2009-2013) were collected from Haeundae Police Station. A logarithmic transformation was performed to ensure an effective statistical analysis and the number of theft crimes was used as the dependent variable. Related factors were selected through a literature review and divided into social, environmental, and defensive factors. Seven factors, were selected as independent variables: the numbers of foreigners, aged persons, single households, companies, entertainment venues, community security centers, and CCTV (Closed-Circuit Television) systems. OLS (Ordinary Least Squares) and GWR (Geographically Weighted Regression) were used to analyze the relationship between the dependent variable and independent variables. In the GWR results, each independent variable had regression coefficients that differed by location over the study area. The GWR model calculated local values for, and could explain the relationships between, variables more efficiently than the OLS model. Additionally, the adjusted R square value of the GWR model was 10% higher than that of the OLS model, and the GWR model produced a AICc (Corrected Akaike Information Criterion) value that was lower by 230, as well as lower Moran's I values. From these results, it was concluded that the GWR model was more robust in explaining the relationship between the number of thefts and the factors related to theft crime.

• The Journal of Advanced Prosthodontics
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• v.10 no.1
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• pp.8-17
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• 2018

PURPOSE. The study aimed to identify the accuracy and reproducibility of preparations made by gypsum materials of various colors using quantitative and semi-quantitative three-dimensional (3D) approach. MATERIALS AND METHODS. A titanium maxillary first molar preparation was created as reference dataset (REF). Silicone impressions were duplicated from REF and randomized into 6 groups (n=8). Gypsum preparations were formed and grouped according to the color of gypsum materials, and light-scanned to obtain prepared datasets (PRE). Then, in terms of accuracy, PRE were superimposed on REF using the best-fit-algorithm and PRE underwent intragroup pairwise best-fit alignment for assessing reproducibility. Root mean square deviation (RMSD) and degrees of similarity (DS) were computed and analyzed with SPSS 20.0 statistical software (${\alpha}=.05$). RESULTS. In terms of accuracy, PREs in 3D directions were increased in the 6 color groups (from 19.38 to $20.88{\mu}m$), of which the marginal and internal variations ranged $51.36-58.26{\mu}m$ and $18.33-20.04{\mu}m$, respectively. On the other hand, RMSD value and DS-scores did not show significant differences among groups. Regarding reproducibility, both RMSD and DS-scores showed statistically significant differences among groups, while RMSD values of the 6 color groups were less than $5{\mu}m$, of which blue color group was the smallest ($3.27{\pm}0.24{\mu}m$) and white color group was the largest ($4.24{\pm}0.36{\mu}m$). These results were consistent with the DS data. CONCLUSION. The 3D volume of the PREs was predisposed towards an increase during digitalization, which was unaffected by gypsum color. Furthermore, the reproducibility of digitalizing scanning differed negligibly among different gypsum colors, especially in comparison to clinically observed discrepancies.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.6
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• pp.2889-2909
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• 2017

Wireless sensor networks (WSNs) have attracted lots of attention in recent years due to their potential for various applications. In this paper, we seek how to efficiently deploy relay nodes into traditional static WSNs with constrained locations, aiming to satisfy specific requirements of the industry, such as average energy consumption and average network reliability. This constrained relay node deployment problem (CRNDP) is known as NP-hard optimization problem in the literature. We consider addressing this multi-objective (MO) optimization problem with an improved Artificial Bee Colony (ABC) algorithm with a linear local search (MOABCLLS), which is an extension of an improved ABC and applies two strategies of MO optimization. In order to verify the effectiveness of the MOABCLLS, two versions of MO ABC, two additional standard genetic algorithms, NSGA-II and SPEA2, and two different MO trajectory algorithms are included for comparison. We employ these metaheuristics on a test data set obtained from the literature. For an in-depth analysis of the behavior of the MOABCLLS compared to traditional methodologies, a statistical procedure is utilized to analyze the results. After studying the results, it is concluded that constrained relay node deployment using the MOABCLLS outperforms the performance of the other algorithms, based on two MO quality metrics: hypervolume and coverage of two sets.

• The Korean Journal of Applied Statistics
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• v.29 no.7
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• pp.1213-1229
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• 2016

Cho and Shin (2016) recently demonstrated that an integrated HAR model has a forecast advantage over the HAR model of Corsi (2009). Recalling that realized volatilities of financial assets have asymmetries, we add a leverage term to the integrated HAR model, yielding the LIHAR model. Out-of-sample forecast comparisons show superiority of the LIHAR model over the HAR and IHAR models. The comparison was made for all the 20 realized volatilities in the Oxford-Man Realized Library focusing specially on the DJIA, the S&P 500, the Russell 2000, and the KOSPI. Analysis of the realized volatility data sets reveal apparent long-memory and asymmetry. The LIHAR model takes advantage of the long-memory and asymmetry and produces better forecasts than the HAR, IHAR, LHAR models.

• Korean Journal of Applied Biomechanics
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• v.25 no.1
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• pp.29-37
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• 2015

Objective : The purpose of this study was to investigate the biomechanical properties of shock absorption strategy and postural stability during the drop landing for each types. Methods : The motions were captured with Vicon Motion Capture System, with the fourteen infra-red cameras (100Hz) and synchronized with GRF(ground reaction force) data(1000Hz). Ten male soccer players performed a drop landing with single-leg and bi-legs on the 30cm height box. Dependent variables were the CoM trajectory and the Joint Moment. Statistical computations were performed using the paired t-test and ANOVA with Turkey HSD as post-hoc. Results : The dominant leg was confirmed to show a significant difference between the left leg and right leg as the inverted pendulum model during Drop Landing(Phase 1 & Phase 2). One-leg drop landing type had the higher CoM displacement, the peak of joint moment with the shock absorption than Bi-leg landing type. As a lower extremity joint kinetics analysis, the knee joint showed a function of shock absorption in the anterior-posterior, and the hip joint showed a function of the stability and shock absorption in the medial-lateral directions. Conclusion : These findings indicate that the instant equilibrium of posture balance(phase 1) was assessed by the passive phase as Class 1 leverage on the effect of the stability of shock absorption(phase 2) assessed by the active phase on the effect of Class 2 leverage. Application : This study shows that the cause of musculo-skeletal injuries estimated to be focused on the passive phase of landing and this findings could help the prevention of lower damage from loads involving landing related to the game of sports.

• Journal of Korea Society of Industrial Information Systems
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• v.20 no.3
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• pp.61-69
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• 2015

This study presents a probabilistic knowledge discovery method to interpret heart rate variability (HRV) based on time and frequency domain indexes, extracted using discrete wavelet transform. The knowledge induction algorithm was composed of two phases: rule generation and rule estimation. Firstly, a rule generation converts numerical attributes to intervals using ROC curve analysis and constructs a reduced ruleset by comparing consistency degree between attribute-value pairs with different decision values. Then, we estimated three measures such as rule support, confidence, and coverage to a probabilistic interpretation for each rule. To show the effectiveness of proposed model, we evaluated the statistical discriminant power of five rules (3 for atrial fibrillation, 1 for normal sinus rhythm, and 1 for both atrial fibrillation and normal sinus rhythm) generated using a data (n=58) collected from 1 channel wireless holter electrocardiogram (ECG), i.e., HeartCall$^{(R)}$, U-Heart Inc. The experimental result showed the performance of approximately 0.93 (93%) in terms of accuracy, sensitivity, specificity, and AUC measures, respectively.

• Korean Journal of Health Education and Promotion
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• v.34 no.1
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• pp.1-12
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• 2017

Objectives: The aim of this study was to verify relationships between light- and heavy alcohol drinking and health-risk behaviors such as smoking, inappropriate weight control, physical inactivity, and sexual activity among adolescents. Methods: The data of 68,043 adolescents in middle- and high school collected from the Korea Youth Risk Behavior Web-based Survey in 2015 were analyzed. For statistical analysis, logistic regression model was used. Results: The rate of heavy alcohol drinking increased with increasing age up to 21.5% among boys and 13.9% among girls. Among boys, heavy alcohol drinkers were at a higher risk of smoking (adjusted odds ratios [OR]=3.3, 95% confidence interval [CI]=2.8-3.8), inappropriate weight control (OR=1.7; 95% CI=1.4-2.1), having sexual intercourse (OR=3.6; 95% CI=3.0-4.2) than light drinkers. Multiple health-risk behaviors of smoking, inappropriate weight control and sexual intercourse also increased in accordance with the severity of drinking alcohol beverage compared to non-drinker. Physical inactivity was decreased among heavy drinkers compared to light drinkers (OR=0.8; 95% CI=0.7-0.9 for inactivity of moderate exercise). Similar results were observed among girls. Conclusions: Alcohol drinking especially heavy alcohol drinking among adolescents is related to other risky behaviors including smoking, inappropriate weight control, and sexual activity. To prevent health problems in adolescents, it is necessary to adopt a combined approach regarding heavy drinking and health-risk behaviors.

• Journal of Families and Better Life
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• v.34 no.6
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• pp.69-85
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• 2016

This study examined bidirectional associations between intergenerational residential proximity and older parents' mental and physical health. The data were drawn from first three waves of the Korean Longitudinal Study of Ageing (KLoSA, 2006, 2008, 2010), a nationally representative sample of adults 45 years or older and their spouses. The analytic sample consisted of 2,391 parents aged 60 years or older with at least one child who were continuously married between 2006 and 2010. Intergenerational residential proximity was measured with travel time between parental residence and that of the oldest of the continuously married children. For statistical analysis, autoregressive cross-lagged models were estimated using AMOS. Findings suggest that intergenerational residential proximity may have bidirectional associations with functional health, and an unidirectional association with life satisfaction. Specifically, a closer distance to a married son or daughter reported in 2006 was associated with poorer functional health of the parent in 2008. An older parent's greater number of functional limitations in 2006 was also related to a closer residential proximity to the married child in 2008. A greater residential proximity to a son, but not a daughter, reported in 2006 was associated with a higher level of parental life satisfaction in 2008. Overall, results suggest that having nearby a married adult child, particularly a married son, may help maintain parental health.

• Journal of the Korea Convergence Society
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• v.8 no.12
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• pp.391-395
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• 2017

In this research, we conducted a questionnaire survey of contents necessary for eyeglass dispensing & fitting fee and characterization solution of eyeglass dispensing & fitting fee. From August 1, 2016 to September 30, questionnaires were set up for 202 spectators of Seoul and Gyeonggi area, questionnaire survey was conducted online and offline. Statistical processing of all data was performed using Origin Pro 8.5. 92.1% (186 people) and 93.1% (188 people) were positively evaluating the necessity of introduction for the necessity of introducing eyeglass dispensing & fitting fee, respectively. The result suggested that it is necessary to establish the position of the optician as a medical service expert by providing a more stable policy through analysis of overseas cases of eyeglass dispensing & fitting fee.

• Informatization Policy
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• v.17 no.4
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• pp.3-22
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• 2010

The purpose of this study is to provide the fruitful directions for the future studies on smart work by analyzing the past and present trends that are related to smart work. For this, a wide range of materials and MA and PhD treatises produced from 1992 to the present have been collected and have been analyzed on the basis of various standards, including objective of study, approach method, methodology, method of data collection, statistical technique of analysis, summary of problems and alternativesto overcome limitations. Lessons and implications of this study for the possibility of smart work are presented. I hope this study will contributeto future studies concerned about smart work.