• Journal of the Earthquake Engineering Society of Korea
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• v.9 no.2 s.42
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• pp.37-46
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• 2005

To date, many viable smart base isolation systems have been proposed and investigated. In this study, a novel friction pendulum system (FPS) and an MR damper are employed as the isolator and supplemental damping device, respectively, of the smart base isolation system. A fuzzy logic controller (FLC) is used to modulate the MR damper because the FLC has an inherent robustness and ability to handle non linearities and uncertainties. A genetic algorithm (GA) is used for optimization of the FLC. The main purpose of employing a GA is to determine appropriate fuzzy control rules as well to adjust parameters of the membership functions. To this end, a GA with a local improvement mechanism is applied. This method is efficient in improving local portions of chromosomes. Neuro fuzzy models are used to represent dynamic behavior of the MR damper and FPS. Effectiveness of the proposed method for optimal design of the FLC is judged based on computed responses to several historical earthquakes. It has been shown that the proposed method can find optimal fuzzy rules and the GA optimized FLC outperforms not only a passive control strategy but also a human designed FLC and a conventional semi active control algorithm.

• The Korean Journal of Elementary Counseling
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• v.10 no.1
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• pp.19-38
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• 2011

The purpose of this study was to develop a cognitive-behavioral academic stress coping training for reduction of elementary school children's academic stress and improvement the ability to handle academically stressful situation with effective way, to examine its effects. For this, we assigned students of Y elementary school in Gyeongnam Province to two groups at random. From a group of 12 each, one group became the experimental group and the other the control group. And the program was applied twice a week to the experimental group who had totally six 40 minutes sessions of the research own making. Moreover, students evaluated the effects of the program via questionnaire regarding to academic stress and strategy for it. From 120 students of Y elementary school in Gyeongnam province for 3weeks, the study gathered data through the questionnaire for academic stressful situation to know this which students of elementary school often experience. From this, the results are reflected in the program. Also cognitive behavioral group counselling program for teenagers in crisis and existing programs used to adjust academic stress was redeveloped as available form for students in elementary school to compose the cognitive-behavioral Academic stress coping training. In short, the results of the study is as follows. In the study, first, It was showed that cognitive-behavioral academic stress coping training decreased stress which can be caused in situation causing academic stress with a school record, lesson, study and task. Second, The cognitive-behavioral academic stress coping training showed the effect to improve coping strategy for academic stress. In detail, a passive-aversive coping strategy and a helpful coping strategy of coping strategy was enhanced meaningfully but the effect getting to an active coping strategy was limited.

• Journal of Life Science
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• v.31 no.9
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• pp.849-855
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• 2021

Recently, as nanotechnology has been introduced and used in various fields, the development of new drugs has been accelerating. Nanoparticles have maintained blood drug concentration for extended periods of time with a single administration of the drug. The drug can then be selectively released only at the pathological site, thereby reducing side effects to other non-pathological sites. In addition, nanoparticles can be modified for selective target sites delivery for other specific diseases, with polymers being widely used in the manufacture of these nanoparticles. Poly (D,L-lactic-co-glycolic acid ) (PLGA) is one of the most extensively developed biodegradable polymers. PLGA is widely used in drug delivery for a variety of applications. It has also been approved by the FDA as a drug delivery system and is widely applied in controlled release formulations, such as in gene therapy treatments. PLGA nanoparticles have been developed as delivery systems with high efficiency to specific cell types by using passive and active targeting methods. After the development of a drug delivery system using PLGA nanoparticles, the drug is selectively delivered to the target site, and the effective blood concentration for extended periods of time is optimized according to the disease. In this review paper, we focus on ways to improve cell-specific treatment outcomes by examining the development of astrocyte selective nanoparticles based on PLGA nanomaterials for gene therapy.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.24 no.1
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• pp.69-78
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• 2011

In this study, an optimization method using multi-objective genetic algorithm(MOGA) has been proposed to develop a fuzzy control algorithm that can effectively control a smart tuned mass damper(TMD). A 76-story benchmark building subjected to wind load was selected as an example structure. The smart TMD consists of 100kN MR damper and the natural period of the smart TMD was tuned to the first mode natural period of the example structure. Damping force of MR damper is controlled to reduce the wind-induced responses of the example structure by a fuzzy logic controller. Two input variables of the fuzzy logic controller are the acceleration of 75th floor and the displacement of the smart TMD and the output variable is the command voltage sent to MR damper. Multi-objective genetic algorithm(NSGA-II) was used for optimization of the fuzzy logic controller and the acceleration of 75th story and the displacement of the smart TMD were used as objective function. After optimization, a series of fuzzy logic controllers which could appropriately reduce both wind responses of the building and smart TMD were obtained. Based on numerical results, it has been shown that the control performance of the smart TMD is much better than that of the passive TMD and it is even better than that of the sample active TMD in some cases.

• Journal of dental hygiene science
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• v.16 no.6
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• pp.472-480
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• 2016

In this study, 110 adults aged 40 to 69 years were surveyed from April 28, 2016, to May 28, 2016 to analyze their periodontal status according to daily stress, coping methods, and oral health behavior. The collected data were analyzed using the t-test, one-way analysis of variance, and hierarchical multiple regression. Daily stress levels of all subjects were most frequent potential risk 64.5% of the subjects, the high risk 19.1% and 16.4% of the health group. Regarding stress coping methods, active methods recorded 2.46, passive methods recorded 2.32. Regarding oral health behaviors, subjects brushed an average of 2.45 times daily, for an average of 2 minutes. Futhermore, 69.1% of subjects brushed before bedtime and 89.1% practiced scaling. Regarding periodontal status, the O'Leary index was 73.45, gingivitis index was 1.30, an average of 2.83 quadrants possessed a periodontal pocket. The hierarchical multiple regression analysis identified, type of employment (${\beta}=-0.348$), scaling (${\beta}=-0.253$), and age (${\beta}=0.244$) as factors that influence the number of quadrants possessing a periodontal pocket. These results confirmed that the oral health behavior of scaling, but not stress levels of coping methods, strongly influenced periodontal status.

• Korean Journal of Childcare and Education
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• v.11 no.1
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• pp.1-22
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• 2015

This study analyzed the policies related to parents in child care centers from 1991 to 2013 as shown in the guidance for child care business book published by the government and accredited journals by the National Research Foundation. Policies related to parents in child care centers were divided into the following periods: 1) the period of passive parent education focused on low-income families (1991-1994), 2) the period of relief for dual-income families (1995-1997), 3) the period of relief for adoption families and the practice of child care support services (2004-2007), 4) the period of active parent involvement (2008-2013). On the other hand, the research trends of parent education in child-care centers were as follows: 1) the survey of parent education was the most common at first, 2) the studies of the role and disposition of parents occupied the bulk, 3) the studies of parents' needs and satisfaction on parent involvement appeared plenty, 4) the studies of the personalized parent education increased. Consequently, the need for home care services and the importance of parents' education were suggested.

• Journal of Broadcast Engineering
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• v.18 no.2
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• pp.225-236
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• 2013

3D contents could cause unique 3D visual fatigue. Screen disparity, image blurring, and crosstalk are known to be the three major factors responsible for the fatigue. Among these, screen disparity and image blurring are content factors, that is, one can directly manipulate contents themselves to handle visual fatigue caused by these two factors. On the other hand, because crosstalk is closely tied to physical characteristics of 3D display, it is difficult or even impossible to reduce crosstalk-driven visual fatigue unless one replaces 3D display itself (for example, from active to passive display). However, the effects of crosstalk on 3D visual fatigue depends on visual stimulus features (that is, contents), and thus it is possible to manipulate stimulus features in order to handle visual fatigue caused by crosstalk. Hence, this research tested the effects of visual stimulus features on crosstalk (which then causes 3D visual fatigue). Using relative depth discrimination task, we tested the effects of stimulus-background contrast, background texture density, and screen disparity on the degree of perceived crosstalk. The results showed that crosstalk decreases with presence of background texture and with less degree of screen disparity.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.4
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• pp.2465-2477
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• 2015

The number of emigrants along with globalization and internationalization is rapidly increasing. The international migration is creating a new form of acculturation and a new structure of society. Racial or cultural diversity resulting from political, economical, and cultural exchange is drastically increasing. This study aimed to provide policy plans or basic data to improve multicultural acceptability in the future. Accordingly, it was also to set and verify causal effect of multicultural acceptability. For those purposes, a questionnaire was made up based on the literature about acculturation, and a survey was taken in korean. The results are as follows. Dependant variables used in analysis were sub-factors of multicultural acceptability founding three types called 'The Actual Acceptance', 'The Active Acceptance', 'The Passive Acceptance'. It was found that positive effect in multicultural acceptability through media experience was an important factor to reduce discriminant of multicultural community members. Therefore, we need to produce diverse media programs that can improve multicultural acceptability and reduce negative perception of multicultural community members. Additionally, multiculture education to help understanding of other races and other cultures should be developed as subject courses in university.

• Journal of the Korea institute for structural maintenance and inspection
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• v.14 no.4
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• pp.55-61
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• 2010

This paper is concerned with an experimental research to random vibration control caused by external loads specially in bridges which tend to be structurally flexible. Experimenting on a reduced structure modelled on Seohae Grand Bridge, we inflicted a reduced form of El-centro wave on the model structure to a proper proportion. On the center of its middle span, we placed a shear type MR damper which was to control its vibration and also acquire its structural responses such as displacement and acceleration at the same site. The experiments concerning controlling vibration were performed according to a variety of theories including un-control, passive on/off control, and Lyapunov stability theory. Its control performance was evaluated in terms of the peak absolute displacements, the peak absolute accelerations and the total power required to control the bridge which differ from each different experiment method. Among all the methods applied in this paper, case of Lyapunov control method turned out to be the most effective to reduces of displacement and acceleration. Also, this method could to decrease consuming of external power for vibration control. Finally, it was noteworthy that Lyapunov control method was specially effective in the vibration control employing a semi-active damper such MR damper.

• The Korean Journal of Physiology
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• v.14 no.2
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• pp.7-16
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• 1980

The effects of various inotropic interventions on the shape of the steady state length tension relation and the length-dependent activation process in cardiac muscle were studied. The influence of inotropic interventions upon the action potential was also observed. The range of varying muscle length was from the optimal length$(l_{max})$, where the active tension production is maximal, to 0.85 $l_{max}$. Changes in stimulus frequency or in external bathing Ca concentration constituted the inotropic interventions in this experiment. The papillary muscles were isolated from the rabbit right ventricles and perfused with $HCO-_3\;-buffered$ normal Tyrode solution which was aerated with $3%\;CO_2-97%\;O_2$ mixed gas and kept at $35^{\circ}C$. Resting Passive tension at $l_{max}$ was approximately 30% of the total tension and appeared from the muscle length of 0.90 $l_{max}$. The effect of stimulus frequency on the steady state level of developed tension was: As the stimulus frequency was increased from 0.1 to 0.5 Hz, there was little change in developed tension. As the frequency was increased further, to a value of about 3 Hz, tension increased steeply. Further increase of the frequency to 5 Hz had little additional effect on the developed tension. The length-tension curves for isometric peak tension became more steeper with the degree of potentiation by inotropic interventions. The relative steepness of the normalized length-tension curves where tension production was expressed as a percentage of maximal tension developed at $l_{max}$, varied inversely with the level of inotropic state and these curves were not superimposable one another. Thus at the stimulus frequency of 2 Hz or at the external Ca concentration of 8 mM, the relative decline in the developed tension for a given change in muscle length was considerably less than the decline observed at the frequency of 0.5 Hz or at the concentration of 2 mM Ca. Action potential duration was prolonged significantly as the frequency increased from 0.2 to 2 Hz, and this change in action potential duration was not observable on the changes in muscle length. There was a tendency of the hyperpolarization of membrane potential when the muscle length was shortened from $l_{max}$ to 0.95 $l_{max}$. These results support the hypothesis that there is a length-dependence of the activation process.