• Journal of the Korea Convergence Society
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• v.9 no.11
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• pp.169-177
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• 2018

This convergence study was combined research on identifying the effect of health behavior and awareness of Korean wave (Hallyu) on academic adjustment of foreign students living in Korea, and providing support for future foreign students to easily adjust to Korean culture. The subjects for this study are foreign students attending G University and were studied from April 2nd to 30th,2018. The collected data were analyzed using SPSS statistical program. According to the multiple regression analysis which was conducted to analyze the effect of health behavior and awareness of Korean wave on academic adjustment of foreign students, the older and the longer the stay, the poorer the academic adjustment; on the other hand, the higher the frequency of exercise and awareness of Korean wave, the better the academic adjustment. Further, it is necessary to address plans and measures to develop academic adjustment of foreign students by providing health care programs and Korean wave culture programs on sustainable health education and sports.

• Journal of Power Electronics
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• v.19 no.5
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• pp.1303-1314
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• 2019

This paper studies the harmonic characteristics of ship electric propulsion systems and their treatment methods. It also adopts effective measures to suppress and prevent ship power systems from affecting ship operation due to the serious damage caused by harmonics. Firstly, the harmonic characteristics of a ship electric propulsion system are reviewed and discussed. Secondly, aiming at problems such as resonant frequency and filter characteristics variations, resonance point migration, and unstable filtering performances in conventional passive filters, a method for fully tuning of a passive dynamic tunable filter (PDTF) is proposed to realize harmonic suppression. Thirdly, to address the problems of the uncontrollable inductance L of traditional air gap iron core reactors and the harmonics of power electronic impedance converters (PEICs), this paper proposes an electromagnetic coupling reactor with impedance transformation and harmonic suppression characteristics (ECRITHS), with the internal filter (IF) designed to suppress the harmonics generated by PEICs. The ECRITHS is characterized by both harmonic suppression and impedance change. Fourthly, the ECRITHS is investigated. This investigation includes the harmonic suppression characteristics and impedance transformation characteristics of the ECRITHS at the fundamental frequency, which shows the good performance of the ECRITHS. Simulation and experimental evaluations of the PDTF are carried out. Multiple PDTFs can be configured to realize multi-order simultaneous dynamic filtering, and can effectively eliminate the current harmonics of ship electric propulsion systems. This is done to reduce the total harmonic distortion (THD) of the supply currents to well below the 5% limit imposed by the IEEE-519 standard. The PDTF also can eliminate harmonic currents in different geographic places by using a low voltage distribution system. Finally, a detailed discussion is presented, with challenges and future implications discussed. The research results are intended to effectively eliminate the harmonics of ship electric power propulsion systems and to improve the power quality of ship power systems. This is of theoretical and practical significance for improving the power quality and power savings of ship power systems.

• Ocean Systems Engineering
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• v.9 no.3
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• pp.287-328
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• 2019

Comprehensive understanding of the flood risk assessments via frequency analysis often demands multivariate designs under the different notations of return periods. Flood is a tri-variate random consequence, which often pointing the unreliability of univariate return period and demands for the joint dependency construction by accounting its multiple intercorrelated flood vectors i.e., flood peak, volume & durations. Selecting the most parsimonious probability functions for demonstrating univariate flood marginals distributions is often a mandatory pre-processing desire before the establishment of joint dependency. Especially under copulas methodology, which often allows the practitioner to model univariate marginals separately from their joint constructions. Parametric density approximations often hypothesized that the random samples must follow some specific or predefine probability density functions, which usually defines different estimates especially in the tail of distributions. Concentrations of the upper tail often seem interesting during flood modelling also, no evidence exhibited in favours of any fixed distributions, which often characterized through the trial and error procedure based on goodness-of-fit measures. On another side, model performance evaluations and selections of best-fitted distributions often demand precise investigations via comparing the relative sample reproducing capabilities otherwise, inconsistencies might reveal uncertainty. Also, the strength & weakness of different fitness statistics usually vary and having different extent during demonstrating gaps and dispensary among fitted distributions. In this literature, selections efforts of marginal distributions of flood variables are incorporated by employing an interactive set of parametric functions for event-based (or Block annual maxima) samples over the 50-years continuously-distributed streamflow characteristics for the Kelantan River basin at Gulliemard Bridge, Malaysia. Model fitness criteria are examined based on the degree of agreements between cumulative empirical and theoretical probabilities. Both the analytical as well as graphically visual inspections are undertaken to strengthen much decisive evidence in favour of best-fitted probability density.

• Journal of Periodontal and Implant Science
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• v.49 no.3
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• pp.185-192
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• 2019

Purpose: Implant wall thickness and the height of the implant-abutment interface are known as factors that affect the distribution of stress on the marginal bone around the implant. The goal of this study was to evaluate the long-term effects of supracrestal implant placement and implant wall thickness on maintenance of the marginal bone level. Methods: In this retrospective study, 101 patients with a single implant were divided into the following 4 groups according to the thickness of the implant wall and the initial implant placement level immediately after surgery: 0.75 mm wall thickness, epicrestal position; 0.95 mm wall thickness, epicrestal position; 0.75 mm wall thickness, supracrestal position; 0.95 mm wall thickness, supracrestal position. The marginal bone level change was assessed 1 day after implant placement, immediately after functional loading, and 1 to 5 years after prosthesis delivery. To compare the marginal bone level change, repeated-measures analysis of variance was used to evaluate the statistical significance of differences within groups and between groups over time. Pearson correlation coefficients were also calculated to analyze the correlation between implant placement level and bone loss. Results: Statistically significant differences in bone loss among the 4 groups (P<0.01) and within each group over time (P<0.01) were observed. There was no significant difference between the groups with a wall thickness of 0.75 mm and 0.95 mm. In a multiple comparison, the groups with a supracrestal placement level showed greater bone loss than the epicrestal placement groups. In addition, a significant correlation between implant placement level and marginal bone loss was observed. Conclusions: The degree of bone resorption was significantly higher for implants with a supracrestal placement compared to those with an epicrestal placement.

• Journal of Agricultural Extension & Community Development
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• v.26 no.2
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• pp.85-97
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• 2019

The conflict management of forest recreation, especially conflict management between hikers and MTB users, has drawn much attention as one of major issues in forest policy making. The main purpose of this study was to investigate hikers' conflict perception against MTB users and their attitudes toward the necessity of conflict management actions, and to identify factors influencing those attitudes. The research data were collected through online surveys of 644 men and women hikers who are aged 20 or older and not participating in MTB riding. The major findings of this study can be summarized as follows: First, the levels of goal interference and social value conflicts against MTB users were not so high, but rather, the awareness level of compatibility was much higher than that of conflict, and hikers' awareness level of safety risks posed by MTB users was also considerably high. Second, hikers' attitudes toward the necessity of conflict management actions were generally shown to be considerably positive, but those attitudes toward indirect management actions such as information, education, and compliance with norms of conduct, were significantly positive than those attitudes toward direct management measures such as zoning, enforcement, and regulations. Finally, the results of the multiple regression analysis showed that four factors that most significantly affect hikers' attitudes toward direct or indirect conflict management actions are behavioral norms conflict, safety risk, compatibility and age. Safety risks had most important influence on hikers' attitudes toward the direct management actions, but behavioral norms conflicts had most important influence on indirect management actions.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.6
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• pp.3199-3218
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• 2019

Location-based services (LBSs) have become popular in recent years due to the ever-increasing usage of smart mobile devices and mobile applications through networks. Although LBS application provides great benefits to mobile users, it also raises a sever privacy concern of users due to the untrusted service providers. In the lack of privacy enhancing mechanisms, most applications of the LBS may discourage the user's acceptance of location services in general, and endanger the user's privacy in particular. Therefore, it is a great interest to discuss on the recent privacy-preserving mechanisms in LBSs. Many existing location-privacy protection-mechanisms (LPPMs) make great efforts to increase the attacker's uncertainty on the user's actual whereabouts by generating a multiple of fake-locations together with user's actual positions. In this survey, we present a study and analysis of existing LPPMs and the state-of-art privacy measures in service quality aware LBS applications. We first study the general architecture of privacy qualification system for LBSs by surveying the existing framework and outlining its main feature components. We then give an overview of the basic privacy requirements to be considered in the design and evaluation of LPPMs. Furthermore, we discuss the classification and countermeasure solutions of existing LPPMs for mitigating the current LBS privacy protection challenges. These classifications include anonymization, obfuscation, and an encryption-based technique, as well as the combination of them is called a hybrid mechanism. Finally, we discuss several open issues and research challenges based on the latest progresses for on-going LBS and location privacy research.

• Journal of the Korean society of biological therapies in psychiatry
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• v.24 no.3
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• pp.163-172
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• 2018

Objectives : The aim of this study was to examine associations between quality of life in patients with schizophrenia and their family relationships. Methods : A total of 68 patients with schizophrenia participated in the study. Socio-demographic and clinical data were collected, as well as results from the Subjective Well-being under Neuroleptic Treatment Scale-Short Form(SWN-K), Family Emotional Involvement and Criticism Scale(FEICS), a visual analogue scale for evaluating the degree of perceived criticism(VAS), the Family Adaptability and Cohesion Evaluation Scale(FACES), Beck Cognitive Insight Scale(BCIS), and Rosenberg Self Esteem Scale(R-SES). Psychiatrists administered the Positive and Negative Syndrome Scale and the Calgary Depression Scale for Schizophrenia(CDSS), and collected a history of previous suicide attempts. Results : The SWN-K total scores showed significant negative correlations with scores on the FEICS perceived criticism, CDSS, and VAS measures and significant positive correlations with scores on the R-SES, FACES, and BCIS. Multiple regression analysis revealed that FEICS perceived criticism, FACES, and BCIS scores were significantly associated with SWN-K scores. The FACES total score was significantly lower in patients with a history of previous suicide attempt. Conclusion : The quality of life of patients with schizophrenia was negatively associated with greater perceived familial criticism and positively associated with better family cohesion and higher patient insight. In patients with a history of suicide attempts, family adaptability and cohesion were significantly low.

• Journal of the Korean Society of Physical Medicine
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• v.14 no.1
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• pp.139-150
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• 2019

PURPOSE: This study was conducted to determine the effects of treadmill gait training with obstacle-crossing on the static and dynamic balance ability of patients with post stroke hemiplegia. METHODS: Twenty-one patients with post stroke hemiplegia were divided into three groups as: treadmill gait training with obstacle-crossing (TOG, n=7), treadmill gait training without obstacle-crossing (TGG, n=7) and a control (CON, n=7). TOG and TGG performed exercise for 20 minutes, three times a week for 8 weeks. Static balance ability (stability typical, ST; weight distribution index, WDI; fourier harmony index, FHI; and fall index, FI) and dynamic balance ability (berg balance scale, BBS and timed up and go test, TUG) were measured before and after 8 -weeks in each exercise group. Statistical analyses were conducted using two-way ANOVA with repeated measures, a paired t-test, and multiple comparisons according to Tukey's HSD. RESULTS: FHI and BBS were significantly increased at TOG (p<.01) and TGG (p<.05) after 8-weeks compared to before treadmill gait training with obstacle-crossing. FHI and BBS were significantly increased at TOG compared with CON and TGG (p<.05). CONCLUSION: Treadmill gait training with obstacle-crossing was more effective than that without obstacle-crossing to improve posture control and independent daily life performance of hemiplegia patients.

• The Journal of Advanced Prosthodontics
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• v.10 no.6
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• pp.415-421
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• 2018

PURPOSE. This study investigated the effects of abutment screw lengths on screw loosening and removal torque in external connection implants after oblique cyclic loading. MATERIALS AND METHODS. External connection implants were secured with abutment screws to straight abutments. The abutment-implant assemblies were classified into seven groups based on the abutment screw length, with each group consisting of five assemblies. A cyclic load of 300 N was applied at a $30^{\circ}$ angle to the loading axis until one million cycles were achieved. Removal torque values (RTVs) before and after loading, and RTV differences were evaluated. The measured values were analyzed using repeated measures of analysis of variance with the Student-Newman-Keuls multiple comparisons. RESULTS. All assemblies survived the oblique cyclic loading test without screw loosening. There was a significant decrease in the RTVs throughout the observed abutment screw lengths when the abutment-implant assemblies were loaded repeatedly (P<.001). However, the abutment screw length did not show significant difference on the RTVs before and after the experiment when the abutment screw length ranged from 1.4 to 3.8 mm (P=.647). CONCLUSION. Within the limit of this experiment, our results indicate that the abutment screw length did not significantly affect RTV differences after oblique cyclic loading when a minimum length of 1.4 mm (3.5 threads) was engaged. These findings suggest that short abutment screws may yield stable clinical outcomes comparable to long screws in terms of load resistance.

• Journal of Korean Clinical Nursing Research
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• v.25 no.1
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• pp.43-54
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• 2019

Purpose: Exposure to blood and body fluids represents a significant occupational risk for nurses. This study was done to identify the level of knowledge of and compliance with blood-borne pathogen prevention of hospital nurses according to clinical experience, and to identify factors affecting compliance with blood-borne pathogen prevention. Methods: A descriptive correlational study was conducted in which self-reported knowledge of and compliance with blood-borne pathogen prevention was assessed. The relationships between variables were examined. Registered nurses who were employed (n=345) were surveyed. Data were analyzed using, t-test, ANOVA, Pearson correlation, and multiple linear regression. Results: Nurses with more than 5 years experience had greater knowledge of blood-borne pathogen prevention than nurses with less than 5 years experience. However, there was no significant difference in compliance with blood-borne pathogen prevention between the two groups. No significant correlation was found between knowledge and compliance with blood-borne pathogen prevention according to experience standards. In nurses with less than 5 years experience, gender, age, reported exposure to a blood-borne pathogen, and compliance with principles of prevention had a significant impact on compliance with blood-borne pathogen prevention. For nurses with more than 5 years experience, reporting after exposure to blood-borne pathogen was a contributing factor to compliance with blood-borne pathogen prevention. Conclusion: The study results show that to improve the implementation of preventive measures against blood-borne pathogens different strategies are needed, depending on clinical experience of the nurses.