• Journal of the Earthquake Engineering Society of Korea
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• v.3 no.3
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• pp.63-74
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• 1999

A sliding mode fuzzy control (SMFC) algorithm is presented for vibration of large structures. Rule-base of the fuzzy inference engine is constructed based on the sliding mode control, which is one of the nonlinear control algorithms. Fuzziness of the controller makes the control system robust against the uncertainties in the system parameters and the input excitation. Non-linearity of the control rule makes the controller more effective than linear controllers. Design procedure based on the present fuzzy control is more convenient than those of the conventional algorithms based on complex mathematical analysis, such as linear quadratic regulator and sliding mode control(SMC). Robustness of presented controller is illustrated by examining the loop transfer function. For verification of the present algorithm, a numerical study is carried out on the benchmark problem initiated by the ASCE Committee on Structural Control. To achieve a high level of realism, various aspects are considered such as actuator-structure interaction, modeling error, sensor noise, actuator time delay, precision of the A/D and D/A converters, magnitude of control force, and order of control model. Performance of the SMFC is examined in comparison with those of other control algorithms such as $H_{mixed 2/{\infty}}$ optimal polynomial control, neural networks control, and SMC, which were reported by other researchers. The results indicate that the present SMFC is an efficient and attractive control method, since the vibration responses of the structure can be reduced very effectively and the design procedure is simple and convenient.

• Nuclear Engineering and Technology
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• v.52 no.6
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• pp.1172-1179
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• 2020

As a Lagrangian particle method, Moving Particle Semi-implicit (MPS) method has great capability to capture interface/surface. In recent years, the multiphase flow simulation using MPS method has become one of the important directions of its developments. In this study, some key methods for multiphase flow have been introduced. The interface tension model in multiphase flow is modified to maintain the smooth of the interface and suitable for the three-phase flow. The mass transfer at immiscible liquid interface entrained by single bubble which could occur in Molten Core-Concrete Interaction (MCCI) has been investigated using this particle method. With the increase of bubble size, the height of entrainment column also increases, but the time of film rupture is slightly different. With the increase of density ratio between the two liquids, the height of entrained column decreases significantly due to the decreasing buoyancy of the denser liquid in the lighter liquid. In addition, the larger the interface tension coefficient is, the more rapidly the entrained denser liquid falls. This study validates that the MPS method has shown great performance for multiphase flow simulation. Besides, the influence of physical parameters on the mass transfer at immiscible interface has also been investigated in this study.

• Journal of fish pathology
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• v.24 no.2
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• pp.85-93
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• 2011

Edwardsiella tarda is a broadly infectious agent against freshwater and seawater fishes. In the present study, E. tarda specific phage was isolated from fish farms on the west coast of Korea, and the effect of environmental factors such as pH and water temperature on the phage activity was investigated. As a fish model, Nile tilapia (Oreochromis niloticus) was used and the interaction between E. tarda and phage was investigated. The phage activity, in pH test, appeared even higher in seawater than freshwater and was evenly constant up to $50^{\circ}C$. The phage and E. tarda were inoculated in tilapia and the phage activity and E. tarda viability were checked on the time intervals. As a result, the number of E. tarda in the group of E. tarda plus phage was constantly reduced to 24 hr post-inoculation compared to the control group without phage, whereas the phage activity was slightly increased in the experiment group. The results suggest that it might be possible to use phage to control the fish disease caused by E. tarda.

• Journal of the HCI Society of Korea
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• v.6 no.1
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• pp.1-8
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• 2011

As virtual realty has become an issue of providing immersive services, in the area of virtual realty, it has been actively investigated to develop user interfaces for immersive interaction. In this paper, we propose a gesture recognition based immersive user interface by using an IR LED embedded helmet and data gloves in order to reflect the user's movements to the virtual reality environments effectively. The system recognizes the user's head movements by using the IR LED embedded helmet and IR signal transmitter, and the hand gestures with the data gathered from data gloves. In case of hand gestures recognition, it is difficult to recognize accurately with the general recognition model because there are various hand gestures since human hands consist of many articulations and users have different hand sizes and hand movements. In this paper, we applied the Mixture-of-Experts based gesture recognition for various hand gestures of multiple users accurately. The movement of the user's head is used to change the perspection in the virtual environment matching to the movement in the real world, and the gesture of the user's hand can be used as inputs in the virtual environment. A head mounted display (HMD) can be used with the proposed system to make the user absorbed in the virtual environment. In order to evaluate the usefulness of the proposed interface, we developed an interface for the virtual orchestra environment. The experiment verified that the user can use the system easily and intuituvely with being entertained.

• Journal of Korean Elementary Science Education
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• v.25 no.3
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• pp.296-306
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• 2006

The purpose of this study is to examine the effectiveness of the summer enrichment programs on Korean gifted students' science learning and creativity development. This program is organized by Purdue University Gilled Education Resource Institute (GERI) in U.S.A. Researchers conducted semi-structured interview with 6 Korean students and observed 12 Korean students and GERI teachers for teacher-student interaction and teaching strategies during science-related classes. From the results, GERI program developed from Purdue 3 stage enrichment model that emphasizes creative teaching strategies, group discussions, and individual research were effective to foster creative thinking of Korean gilled students. Despite their language barriers, Korean gilled students found GERI program experience fun, creative, easy, relaxing, and thereby satisfying for their psychological and academic needs. They expected the level of stimulation in GERI program to be higher and the class to be organized more systematically; however, they reported that the broad range of topics and diverse content of GERI classes helped them develop creativity more than Korean classes. These findings will make contribution to the improvement of the quality of gifted education curriculum and programming in Korea.

• Journal of Periodontal and Implant Science
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• v.46 no.4
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• pp.254-265
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• 2016

Purpose: The aim of this study was to determine the influence of anatomical conditions on primary stability in the models simulating posterior maxilla. Methods: Polyurethane blocks were designed to simulate monocortical (M) and bicortical (B) conditions. Each condition had four subgroups measuring 3 mm (M3, B3), 5 mm (M5, B5), 8 mm (M8, B8), and 12 mm (M12, B12) in residual bone height (RBH). After implant placement, the implant stability quotient (ISQ), Periotest value (PTV), insertion torque (IT), and reverse torque (RT) were measured. Two-factor ANOVA (two cortical conditions${\times}$four RBHs) and additional analyses for simple main effects were performed. Results: A significant interaction between cortical condition and RBH was demonstrated for all methods measuring stability with two-factor ANOVA. In the analyses for simple main effects, ISQ and PTV were statistically higher in the bicortical groups than the corresponding monocortical groups, respectively. In the monocortical group, ISQ and PTV showed a statistically significant rise with increasing RBH. Measurements of IT and RT showed a similar tendency, measuring highest in the M3 group, followed by the M8, the M5, and the M12 groups. In the bicortical group, all variables showed a similar tendency, with different degrees of rise and decline. The B8 group showed the highest values, followed by the B12, the B5, and the B3 groups. The highest coefficient was demonstrated between ISQ and PTV. Conclusions: Primary stability was enhanced by the presence of bicortex and increased RBH, which may be better demonstrated by ISQ and PTV than by IT and RT.

• The Journal of Korean Academic Society of Nursing Education
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• v.5 no.1
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• pp.58-71
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• 1999

Nursing process is an essential part for nursing practice. Nursing faculty members must focus on the clinical application for students and try to identify the possible problems that students might face in the fields. The purpose of this study is to examine the actual condition of nursing process education in curricula and to investigate the response of students in clinical experience of nursing process. From 462 students in the 6 associate programs(ADN) and the 6 baccalaureate programs (BSN) data was collected by questionnaire. The results were as followed. 1. Seven programs (58.3%) opened the nursing process in mainly sophomore (BSN) or freshman(ADN). If not opened, the nursing process was taught at the major subjects(espcially fundamental nursing or adult nursing). 2. All Students responded they we supposed to use nursing process in preparing the case report. The majority(94.6%) used NANDA lists for nursing diagnosis and 55.7% of subjects consulted the Korean terms by KNA when translating. The tutors for nursing process in clinical settings were the professor in charge of the subject (68.6) or clinical instructors (48.1%) , assistants(34%). 3. The problems in clinical application that students experienced consisted of 17 items and the mean was 2.27. The biggest problem was 'the lack of the model for RN of applying the nursing process in clinical settings'(2.97). Next the big problem was 'the lack of the competency for implementing the established nursing plans'(2.69). All items were significantly different according to the level of educational programs(ADN or BSN). ADN students had more problems in applying the each step of nursing process and BSN students perceived the NANDA as a guidance of nursing diagnosis and the inconsistency of advices from several instructors or practicum to be mere problematic. 4. The mean of merits after application of nursing process was relatively fair (2.82). The best merit was 'they can identify nursing problems more exactly'(3.07). The second high merit was 'they can study the rational of nursing action' (3.03). BSN than ADN and the subjects of second year than of one year in clinical experience perceived the use of nursing process to be better. Based on this results we need to enforce the application of nursing diagnosis in the class. The use of sample cases can be the efficient method. Students can identify the possible health problems for patient from the cases in imaginary world and discuss them each other. Also we can use the discussion session after practice every other day or as needed. All this is on the good interaction between tutor and student. We must consider to have enough time for student to seize the essence of the nursing process.

• The Bulletin of The Korean Astronomical Society
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• v.41 no.2
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• pp.42.1-42.1
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• 2016

The formation process and the dynamical properties of a large-scale quasi-circular flare ribbon were investigated using the SDO AIA and HMI data along with data from RHESSI and SOT. Within one hour time interval, two subsequent M-class flares were detected from the NOAA 12371 that had a ${\beta}{\gamma}{\delta}$ configuration with one bipolar sunspot group in the east and one unipolar spot in the west embedded in a decayed magnetic field. Earlier M2.0 flare was associated with a coronal loop eruption, and a two-ribbon structure formed within the bipolar sunspot group. On the other hand, the later M2.6 flare was associated with a halo CME, and a quasi-circular ribbon developed encircling the full active region. The observed quasi-circular ribbon was strikingly large in size spanning 650" in north-south and 500" in east-west direction. It showed the well-known sequential brightening in the clockwise direction during the decay phase of the M2.6 flare at the estimated speed of 160.7 km s-1. The quasi-circular ribbon also showed the radial expansion, especially in the southern part. Interestingly, at the time of the later M2.6 flare, the third flare ribbon parallel to the early two-ribbon structure also developed near the unipolar sunspot, then showed a typical separation in pair with the eastern most ribbon of the early two ribbons. The potential field reconstruction based on the PFSS model showed a fan shaped magnetic configuration including fan-like field lines stemming from the unipolar spot and fanning out toward the background decayed field. This large-scale fan-like field overarched full active region, and the footpoints of fan-like field lines were co-spatial with the observed quasi-circular ribbon. From the NLFF magnetic field reconstruction, we confirmed the existence of a twisted flux rope structure in the bipolar spot group before the first M2.0 flare. Hard X-ray emission signatures were detected at the site of twisted flux rope during the pre-flare phase of the M2.0 flare. Based on the analysis of both two-ribbon structure and quasi-circular ribbon, we suggest that a tether-cutting reconnection between sheared arcade overarching the twisted flux rope embedded in a fan-like magnetic field may have triggered the first M2.0 flare, then secondary M2.6 flare was introduced by the fan-spine reconnection because of the interaction between the expanding field and the nearby quasi-null and formed the observed large-scale quasi-circular flare ribbon.

• International Commerce and Information Review
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• v.16 no.3
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• pp.357-380
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• 2014

Buyers' Trust in suppliers is critical in all commerce, but particularly in the relationship between foreign provider and local consumer due to the liability of foreignness. This study examines (1)how local consumers trust in the product of MNCs is affected by their perceptions of the product attributes, (2)does the product trust affects customers loyalty, and (3)whether Global Corporate Citizenship moderates the relationship between the product attributes and trust. Based on previous researches, hypotheses are formulated and the statistical method used to test them was a moderated regression analysis using SPSS 20. 330 respondents from the university student group in Korea were used for this analysis. The results of this study are follows: Service communication and product perceptions such as quality, technological newness, design, and brand value have a significant effect on the product trust. The Effectiveness of product-related service communication had greater than that of the physical characteristics of product. But, price fairness is not significantly. The trust then has a positive relation to customers loyalty. When global corporate citizenship as the moderating role is introduced into the model, the interaction terms with 'price fairness' are verified to be significant. Therefore, global corporate citizenship moderates the relationship between price fairness and product trust. The results of the empirical study provide important implications for Korean firms operating in foreign markets. But, the findings are limited to the University students and to manufacturing sectors. Thus, the generalization of the results of this research remains limited.

• Journal of Korean Academy of Nursing Administration
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• v.5 no.1
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• pp.87-97
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• 1999

Rapidly changing healthcare environment and professional nursing practice need a strategy for the organizational development and goal attainment. An understanding of organizational culture could help managers enhance or expend their management strategy, thus increasing the probability of their success in the organization. On the other hand. organizational culture is an abstract concept and can show several views between sciences applying it. Therefore. organizational culture can be described to different ways with roots in each other discipline. Thus. it is necessary to define the concept of organizational culture in nursing perspective. This article reports a study conducted to analyze the concept of Nursing Service Organizational Culture. This study is performed by the guideline of Walker and Avant for concept analysis : selecting a concept. detering aim of analysis, identifying all use of concept. defining attributes. constructing model. contrary, borderline. related cases. identifying antecedents and consequences. According to the results of this study. the following definition attributes of Nursing Service Organizational Culture was suggested. We could define that nursing service organizational culture is the pattern of basic assumption and common belief that shared by the subordinates of nursing service. So, it provides a shared identity for all employees. Attributes of Nursing Service Organizational Culture were defined as (1) it is performed by the result of the interaction through formal. informal communication among nursing service organizational subordinations. (2) it has been performed unconsciously and reacts without ever thinking about the behavior. (3) it makes a unique pattern of behaviors to each nursing organization. which is different from other groups. (4) it has a broad and subtle forces to its subordinates. (5) it provides subordinates with the way of thought and behavior. (6) it influences on the output. stability. and de velopment of nursing service.