• Journal of Korean Foot and Ankle Society
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• v.11 no.1
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• pp.8-12
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• 2007

Purpose: The purpose of this study was to investigate the differences in simple radiographic parameters and results of 3-D scan among normal and patient groups. Materials and Methods: Seventy subjects in each group were studied. Control group consisted of subjects without plantar foot pain (normal group), and two patient groups were one with plantar forefoot pain (metatarsalgia group), the other with plantar heel pain (heel pain group). Simple radiographic parameters were obtained and 3-D scan was done with foot scanner (Nexscan, K&I, Korea) and The height and volumn of the space under the medial longitudinal arch was analyzed (Enfoot, K&I, Korea). These parameters were compared and correlation between radiological parameters and results of the 3-D scan were studied. Results: The results of all parameters istributed normally. There was no signigicant differences among the groups in radiological parameters (talo-first metatarsal angle, calcaneal pitch angle and height of the talar head in standing lateral radiograph) and arch height and arch volumn on 3-D scan. There were statistically significant correlations between radiological and 3-D scan results. Conclusion: This study revealed that there is no significant differences in medial longitudinal arch height and volumn among normal and different patient groups and there are variety of arch height in patients with similar symptoms.

• Asia pacific journal of information systems
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• v.25 no.4
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• pp.746-762
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• 2015

This study developed a conceptual model that integrated psychological and physical reactions resulting from online tourism reviews through a longitudinal trust-satisfaction model (LSTM) developed based on the extended valence framework and expectation-confirmation theory. Online reviews are essential factor of consumer's purchase decision. This phenomenon is well applied in a tourism context. However, investigations on online reviews in a longitudinal approach in a tourism context are quite limited. Therefore, this study suggests a conceptual model based on LTSM and several propositions about how online tourism reviews, which are divided into factual and experiential reviews, influence the future travelers' perceptions and attitudes, such as expectation, confirmation, and destination loyalty, in a longitudinal format by examining previous related studies. Finally, expected results were discussed and several implications were described theoretically and practically.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.169-172
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• 2008

Longitudinal elongation develops in reinforced concrete beams that exhibit flexural yielding during cyclic loading. The longitudinal elongation can decrease the shear strength and deformation capacity of the beams. In the present study, nonlinear truss model analysis was performed to study the elongation mechanism of reinforced concrete beams. The results showed that residual tensile plastic strain of the longitudinal reinforcing bar in the plastic hinge is the primary factor causing the member elongation, and that the shear-force transfer mechanism of diagonal concrete struts has a substantial effect on the magnitude of the elongation. Based on the analysis results, a simplified method for evaluating member elongation was developed. The proposed method was applied to test specimens with various design parameters and loading conditions..

• Transactions of Materials Processing
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• v.22 no.7
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• pp.401-406
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• 2013

The use of roll-formed products increases every year due to its advantages, such as high production rates, reduced tooling cost and improved quality. However, till now, it is limited to part profiles with constant cross section. In recent years, the flexible roll forming process, which allows variable cross sections of profiles by adaptive roll stands, was developed. In this study, an attempt to optimize profile design for the flexible roll forming process was performed. An equation that predicts the longitudinal strain for part geometries with variable cross-sections was proposed. The relationship between geometrical parameters and the longitudinal strain was analyzed and investigations on the optimal profile design were performed. Experiments were conducted with a lab-scale roll forming machine to validate the proposed equation. The results show that the profile design method proposed in this study is feasible and parts with variable cross sections can be successfully fabricated with the flexible roll forming process.

• Electrical & Electronic Materials
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• v.8 no.5
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• pp.572-579
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• 1995

Most of conventional ultrasonic transducers are constructed to generate either longitudinal or shear waves, but not both of them. We investigate the mechanism of dual mode transducers that generate both of the longitudinal and shear waves simultaneously with single PZT element. The study is aimed to find the optimally desired cut by examining the anisotropic piezoelectric properties. Theory predicts that a mixed P/S mode transducer can be constructed using a rotated Z-cut of PZT piezoelectric ceramics. We study the performance of a PZT element as a function of its rotation angle so that its efficiency is optimized to excite the two waves as much as equally strong. The results are verified by the waveform in pulse-echo computer simulation and experiments. When the transducer is subjected to impedance analysis, it shows two thickness mode resonances, each of which being a mixed P/S thickness mode. By examining wave speeds on E transmitter delay line receiver setup, it is confirmed that the transducer can transmit and detect both longitudinal and shear wave simultaneously.

• International Journal of Computer Science & Network Security
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• v.21 no.4
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• pp.52-58
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• 2021

Questionnaires and surveys are increasingly being used to collect information from participants of empirical software engineering studies. Usually, such data is analyzed using statistical methods to show an overall picture of participants' agreement or disagreement. In general, the whole survey population is considered as one group with some methods to extract varieties. Sometimes, there are different opinions in the same group, but they are not well discovered. In some cases of the analysis, the population may be divided into subgroups according to some data. The opinions of different segments of the population may be the same. Even though the existing approach can capture the general trends, there is a risk that the opinions of different sub-groups are lost. The problem becomes more complex in longitudinal studies where minority opinions might fade over time. Longitudinal survey data may include several interesting patterns that can be extracted using a clustering process. It can discover new information and give attention to different opinions. We suggest using a data mining approach to finding the diversity among the different groups in longitudinal studies. Our study shows that diversity can be revealed and tracked over time using the clustering approach, and the minorities have an opportunity to be heard.

• The Southeast Asian review
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• v.24 no.2
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• pp.207-251
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• 2014

This study explores the mobility patterns of Korean Early Study Aborad (ESA, hereafter) students in Singapore through a follow-up longitudinal case study, which was initially conducted about five years before this study. This study takes up transnational migration approach, focusing on family strategies and mobilization, which steered their mobility. Interviews with seven original families as well as 7 families additionally recruited in Singapore in 2012 were collected and analyzed by NVivo 9. In short, this study found that transnational mobility is composed of mobilities at global, regional and local levels. There were four types of mobilities; continuation of stay in Singapore, move from a third county to Singapore, return to Korea, and, what this research calls, fluid mobility. Examining the process of these mobilities shows that we need to consider at least three factors (performance of children's schooling; change of family circumstances; context of reception for both Singapore and Korea) as basic backgrounds. On this basis, the interplay between the context of receptions when aspirations for children's advancement by these transnational families made either facilitate or constrain their mobilities: contexts of Singapore and Korea may play a role of hurdle or trampoline. Also, local context of Singapore largely facilitate mobilities of Korean ESA families at both local and global levels.

• Journal of the Ergonomics Society of Korea
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• v.17 no.3
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• pp.91-101
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• 1998

Anthropometric characteristics and considerations of sex differences are essential for the correct design of ergonomic work spaces. This paper is concerned with longitudinal study on the physical growth in the Korean youth. Five hundred and fourty subjects were selected from third year students of high schools, and their records on physical examination during the last twelve years were surveyed by longitudinal method. This study investigated the anthropometric characteristics of physical structure and the shape of physical growth for boys and girls. The result showed that there were significant sex differences in the pattern of physical growth in height.

• Journal of The Korean Association For Science Education
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• v.13 no.3
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• pp.317-326
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• 1993

The purpose of this study was to examine the longitudinal achievement of Science Inquiry Skills. The study compared two data sets collected in May 1992 and April 1993 using the TSIS(Test of Science Inquiry Skills). TSIS consists of 36items which measure 12 science process skills. TSIS's reliability(K-R 20) is O. 86 and test-retest reliability is O.7822.

• Human Ecology Research
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• v.52 no.3
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• pp.301-312
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• 2014

The purpose of this study was to examine whether a temporal relationship would develop between the overuse/addictive use of mobile phones and depression in adolescents. For this study, we used the 4-year longitudinal data (2004-2007, Study 1, which measured the overuse of mobile phones and depression) and the 2-year longitudinal data (2010-2011, Study 2, which measured the addictive use of mobile phones and depression) of the Korea Youth Panel study. In addition, the study explored gender differences with respect to the above mentioned relationship. Autoregressive cross-lagged modeling was carried out, along with a multiple group analysis across genders. The findings showed that the overuse/addictive use of mobile phones and depression in adolescents had a significant effect on the future selves of these adolescents over time. Moreover, the overuse/addictive use of mobile phones had a significant influence on subsequent depression, rather than vice versa. This means that as the overuse/addictive use of mobile phones by adolescents increases, their depression intensifies later on; however, as depression among adolescents intensifies, the overuse/addictive use of mobile phones by adolescents' does not increase. Further, the study showed there were significant gender differences in the longitudinal relationship between the overuse/addictive use of mobile phones and depression. Study 1 shows that, prior to the release of smartphones, the overuse of mobile phones had a definite effect on the depression of only males. However, Study 2 shows that, after the release of smartphones, the effect of the addictive use of mobile phones on depression in females was greater than that in males.