• Structural Engineering and Mechanics
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• v.86 no.2
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• pp.181-195
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• 2023

To predict the rheological behaviours along with the compressive strength of self-compacting concrete that incorporates environmentally friendly ingredients as cement substitutes, a comparative evaluation of machine learning methods is conducted. To model four parameters, slump flow diameter, L-box ratio, V-funnel time, as well as compressive strength at 28 days-a complete mix design dataset from available pieces of literature is gathered and used to construct the suggested machine learning standards, SVM, MARS, and Mp5-MT. Six input variables-the amount of binder, the percentage of SCMs, the proportion of water to the binder, the amount of fine and coarse aggregates, and the amount of superplasticizer are grouped in a particular pattern. For optimizing the hyper-parameters of the MARS model with the lowest possible prediction error, a gravitational search algorithm (GSA) is required. In terms of the correlation coefficient for modelling slump flow diameter, L-box ratio, V-funnel duration, and compressive strength, the prediction results showed that MARS combined with GSA could improve the accuracy of the solo MARS model with 1.35%, 11.1%, 2.3%, as well as 1.07%. By contrast, Mp5-MT often demonstrates greater identification capability and more accurate prediction in comparison to MARS-GSA, and it may be regarded as an efficient approach to forecasting the rheological behaviors and compressive strength of SCC in infrastructure practice.

• Geomechanics and Engineering
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• v.37 no.1
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• pp.1-8
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• 2024

Buckling failure is one of the classical types of catastrophic landslides developing on inclination-paralleled rock slopes, which is mainly governed by its self-weight, earthquake and ground water. However, nearly none of the existing studies fully consider the influence of slope self-weight, earthquake and ground water on the mechanical model of buckling failure. In this paper, based on energy equilibrium principle and elastoplastic slab theory, a thorough mechanical analysis on bucking slopes has been carried out. Furthermore, an analytical solution for slip bucking failure of rock slopes has been proposed, which fully considers the effect of slope self-weight, seismic force and hydrostatic pressure. Finally, the methodology is used to conduct comparative analysis with other analytical solutions for three practical buckling studies. The results show that the proposed approach is capable of providing a more accurate and reasonable evaluation for stability of rock slopes with potential buckling failure.

• Journal of Korean Elementary Science Education
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• v.32 no.3
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• pp.285-297
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• 2013

The purpose of this research is to find the effect of the lesson using open-inquiry report Lubric on open-inquiry standard and science process skill; to find the change of cognition on open-inquiry for elementary school 5th grade students. Two classes (elementary school 5th grade) were selected which located in a small and medium-sized city for this research and they were separated as an experimental group and a comparative group. Open-inquiry lesson was done by referring teaching method which introduced through the curriculum. The procedure was understanding about open-inquiry, making open-inquiry subject, planning, and performing inquiry, mid-term, performing inquiry, making a report, presentation, and evaluation. Open-inquiry report Lubric which developed by Sook-Kyung Kim et al. (2010) was provided to the experimental group. Comparative group was instructed by using open-inquiry report which introduced to the elementary school 5th grade science text book. Interview paper was developed in order to check out the effect of the research by using a test paper of science process skill. The following could be found out through the research. After open-inquiry lesson, 10 open-inquiry reports(5 reports from experimental group, 5 reports from comparative group) have been drawn at random as samples from the total 62 sets (30 reports from experimental group, 32 reports from comparative group) and evaluated by a researcher and two elementary school teachers who have master degree. The reliability of the 3 scorers was 0.923 of mean correlation coefficient. And then the researcher evaluated all open-inquiry reports. The average score of open-inquiry report was 66.78 for experimental group, 54.27 for comparative group, respectively. And there was a significant difference at p<0.05 level as a result of the t-test. The experimental group rated high at p<0.05 level according to the analysis of post-science process skill test. According to the result of survey, both experimental group and comparative group had understood open-inquiry activity. It was especially rated high for experimental group on understanding scientific inquiry process, interest and satisfaction in open-inquiry and re-participation rate. By interviewing experimental group, it is recognized that the students utilized Lubric very well through the overall process. Finally, self-evaluation was done during open-inquiry activity and it was reported that the students gained more knowledge about science and changed to positive about science. As a result, the lesson using open-inquiry report Lubric was effective for students to improve writing skill of an open-inquiry report and science process skill and finally changed the cognition to positive about open-inquiry lesson.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.6B
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• pp.575-583
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• 2004

In this paper, we extend the multiple time scale control framework to the window-based congestion control, in particular, such as the TCP. This is performed by interfacing the TCP with a large time scale control module which adjusts the aggressiveness of the bandwidth consumption behavior exhibited by the TCP as a function of large time scale Self-Similar network state. i.e., conformation that exceeds the horizon of the feedback loop as determined by the RTT. How to effectively utilize such an information-due to its probabilistic nature, dispersion over the multiple time scales, and affection on the top of the existing window-based congestion controls-is a non-trivial problem. The evaluation performance of the multiple time scale TCP is facilitated by a simulation of the bench-mark environment which is based on the physical modeling of a self-similar traffic. We explicate our methodology for discerning and evaluating the impact of changes in transport protocols in the protocol stack under the self-similar traffic conditions. We discuss issues arising in the comparative performance evaluation under heavy-tailed workloads.

• Journal of Korean Academy of Nursing
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• v.29 no.1
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• pp.48-60
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• 1999

This study was done to determine the factors influencing smoking-cessation behavior in female university students. A total of 534 students participated in this cross sectional study by answering a questionnaire. The data collection was done between September 1 and October 31, 1997 The measurement tools used in this study were the self help change process scale (Cronbach's alpha＝.9930 : developed by Oh & Kim, 1996) for smoking-cessation behaviors, the self efficacy scale(Cronbach's alpha＝.8250 : developed by Sherer et al, 1982), the sex role acceptance scale (KR－20＝.7757 : developed by Kim, 1991) and the social support scale(Cronbach's alpha＝.9172 : developed by Park, 1985). The summarized results are follows : 1. The mean scores for smoking-cessation behaviors in smokers (N＝150) was 91.72 that was considered a middle score compared to the total possible score of measurement tool (150.0). The mean score for smoking-cessation behaviors by smoking-cessation step showed significant different between the groups(F＝11.71, p＝.000). 2. The group with no experience in smoking(N＝332) showed a high general self efficacy score (t＝5.24, p＝.000), and more openness to sex role acceptance(t＝-2.15, p＝.032) compared to the group with smoking experience (N＝202). 3. General self efficacy, sex role acceptance, and social support were not different significantly between the groups according to the steps in smoking-cessation. 4. Significant factors influencing smoking-cessation behavior (total, sub concepts) were religion, sex role acceptance, social support, smoking duration, smoking attitude, time of smoking onset, amount of smoking, drinking, and perception of health status. 5. Smoking-cessation behaviors which explained 11% of the variance were smoking attitude, and smoking duration. In conclusion, this study identified factors influencing smoking-cessation behavior. Thereby it will help in the development of smoking-cessation intervention strategies. For future research, exploration other determinants of smoking cessation behaviors, evaluation of intervention efficiency, and comparative study by gender characteristics are needed.

• Restorative Dentistry and Endodontics
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• v.45 no.1
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• pp.10.1-10.8
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• 2020

Objectives: This study aimed to compare the shear bond strength (SBS) of a self-adhering flowable composite (Dyad Flow) and a bulk-fill flowable composite (Smart Dentin Replacement [SDR]) to several pulp-capping materials, including MTA Plus, Dycal, Biodentine, and TheraCal. Materials and Methods: Eighty acrylic blocks with 2-mm-deep central holes that were 4 mm in diameter were prepared and divided into 2 groups (n = 40 each) according to the composite used (Dyad Flow or SDR). They were further divided into 4 sub-groups (n = 10 each) according to the pulp-capping agent used. SBS was tested using a universal testing machine at a crosshead speed of 1 mm/min. Data were analyzed using 2-way analysis of variance. A p value of < 0.05 was considered to indicate statistical significance. Results: A statistically significant difference (p = 0.040) was found between Dyad Flow and SDR in terms of bond strength to MTA Plus, Dycal, Biodentine, and TheraCal. Conclusions: Among the 8 sub-groups, the combination of TheraCal and SDR exhibited the highest SBS.

• Journal of muscle and joint health
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• v.29 no.2
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• pp.91-99
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• 2022

Purpose: The purpose of this study was to examine the level of agreement between smartphone apps and self-reported physical activity questionnaires. Methods: Quantitative methods were used to assess the correlation and agreement between the number of steps counted by a smartphone app and the amount of walking reported in a survey. A total of 29 adults who used smartphones were recruited from a university, and their step counts from their smartphone pedometers and responses to the international physical activity questionnaire (IPAQ) were collected over a 10-week period. Results: An analysis of 170 data pairs with Spearman's rho correlation and a Bland-Altman plot revealed a positive correlation between step counts from the smartphone app and walking activity from the IPAQ. The Bland-Altman plot also demonstrated the agreement to be improved among female participants. Conclusion: In assessing walking activity, smartphone pedometer apps showed good correlation with the IPAQ and improved agreement with the IPAQ among women. Therefore, it is suggested that the participants' gender and activity intensity, as well as the accuracy of measurement tools, should be considered in an evaluation of the delivery of physical activity promotion programs through smartphone apps.

• Magazine of the Korean Society of Agricultural Engineers
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• v.38 no.4
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• pp.99-109
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• 1996

This study, a preliminary one to construction of standardized rural resources evaluation system, aimed at catching the valuing structure of rural and urban residents cn rural resources through interview. The questionnaire employed in our surveys was focussed on; opinion about the advantages and disadvantages of living in rural areas, usual impression on rural life style, viewpoint on preservation of cultural heritages and conservation of natural environments, priority item listing for improvement/development of rural village. Generally, regardless of interviewee's personal characteristics, the peaceful and comfortable life in the lovely/clean environment was indicated as a representative advantage of rural life. However, in minor aspects, there were recognizable differences by their living and thinking patterns, so, a deep and systematic study should be progressed to harmonize or integrate the pluralistic valuing trends on rural affairs in future. The valuing structure on rural resources from this study showed much more varieties according to age-and occupation-groups, while young generation strongly hold self-orii-ented and ambiguous thinking. Because this trend will grow more deeply and widely in future, the resoruces evaluation system for rural purposes should be established as a rational base for decision-making on rural development strategies.

• Journal of the Korean Dietetic Association
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• v.11 no.3
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• pp.309-319
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• 2005

The purpose of this study was to compare the nutritional menu value of self-selected diet in Korean adults residing in different regions. Subjects were recruited and divided into three groups according to the districts where they lived, which included rural district(n=137), coastal district(n=100), and urban district(n=117). Subjects were interviewed using a general questionnaire and 24-hour recall method for dietary intake. The average age of the subjects were 57.5 years for rural district, 57.0 years for coastal district, and 47.9 years for urban district. The contents of energy, calcium, zinc, vitamin $B_2$, and vitamin E in self-selected diet were 76.1%, 60.1%, 73.1%, 68.6%, and 80.4% of RDAs, respectively. Index of nutritional quality(INQ) for calcium and vitamin $B_2$ was below in 1 in region groups. The contents of calcium and vitamin E in self-selected diet of rural and coastal districts were significantly lower than those of urban district. The numbers of food items in diet of rural, coastal, and urban district were 14.6, 15.3, 15.1 for breakfast, 16.5, 11.8, 17.0 for lunch, 14.9, 12.1, 15.1 for dinner, respectively. However, there was no significance in total food intake by regions. The food intakes from cereals, mushrooms, vegetables of rural district, that from fishes of coastal district, and those from sugars, milks, oils of urban district were the highest among three districts. The numbers of dish items in diet of rural, coastal, and urban district were 4.1, 4.4, 4.1 for breakfast, 4.5, 3.7, 4.4 for lunch, 4.0, 3.8, 4.2 for dinner, respectively. Especially, the number of food and dish items in lunch menu of coastal district was the lowest among region groups. According to these results, it could be suggested to add milk and its products in lunch menu of rural and coastal districts and to supplement fish and shellfish like anchovy in diet of rural and urban districts. And it is recommended to increase food and dish items in diets of three region groups.

• Journal of Dental Rehabilitation and Applied Science
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• v.35 no.4
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• pp.220-227
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• 2019

Purpose: The purpose of this study was to compare the degree of tooth preparation abilities of students according to three self-assessment methods. Materials and Methods: forty-eight sophomores in Kyungpook National University College of Dentistry were divided into three experimental groups. Students performed tooth preparation of the left mandibular first molar for full gold crown. They performed self-assessment using the three methods (visual, digital, and putty index self-assessment group), and reperformed tooth preparation. An intraoral scanner was used to scan each tooth model (prepared tooth and unprepared tooth), and data were acquired in standard tessellation language (STL) file format. The STL files of prepared tooth and unprepared tooth were superimposed using the 3-dimensional analysis software (Geomagic control X). And the reduction amount was measured. In the statistical analysis, all values of reduction amount were analyzed with the Wilcoxon signed rank test and Kruskal-Wallis test (α = 0.05). Results: The three self-assessment methods showed statistically significant differences (P < 0.001). The putty index self-assessment group showed the highest reduction in error than the digital self-assessment method. Conclusion: Within limitations of this study, students showed significant differences in improvement of tooth preparation ability according to the three self-evaluation methods.