• Child Health Nursing Research
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• v.16 no.3
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• pp.203-210
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• 2010

Purpose: This study was done to identify cell phone addiction in high school students and variables predicting this addiction. Methods: The participants were 469 adolescents from four high schools. Data were collected through self-report questionnaires, and analyzed using the SPSS program. Results: Of the high school students, 88.4% reported being average users, 7.5%, heavy users, and 4.1%, cell phone addicted. Cell phone addiction was significantly correlated with immediate self-control, self-efficacy, depression, and peer support. Predictors of cell phone addiction were the following: receiving text message on weekends, immediate self-control, main use (text message), minute per call on weekdays, listening to music, gender (female), monthly call charges, depression, person called (friends), and self-efficacy. These factors explained 39% of variance in cell phone addiction. Conclusion: The above findings indicate that cell phone addiction in high school students was influenced by gender, cell phone use, and psychological factors. Therefore the approach to effective cell phone addiction management for high school students is to consider these variables when developing programs for these students.

• Korean Parent-Child Health Journal
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• v.15 no.2
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• pp.60-70
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• 2012

Purpose: This study was done to examine factors influencing cell phone addiction for middle school students by gender. Methods: The participants were 228 male students and 228 female students in two middle schools. Data were collected through self-report questionnaires, and analyzed using the SPSS/WIN 19.0 program. Results: Cell phone addictions of female students are higher than those of male students. Factors influencing cell phone addiction for male students were mimicry, sending text message on weekdays, immediate self-control, grade, syntony, and monthly call charge, explaining 42.2% of variance in cell phone addiction. Factors influencing cell phone addiction for female students were internet addiction, sending and receiving text message on weekends, immediate self-control, long-term self-control, use time, main use, syntony, and monthly call charge, explaining 46.8% of variance in cell phone addiction. Conclusion: The results indicated that cell phone addiction and its influencing factors differed by gender. Therefore the approach to effective cell phone addiction management program for middle school students should consider gender differences.

• Journal of Institute of Control, Robotics and Systems
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• v.18 no.5
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• pp.465-470
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• 2012

This paper proposes a distributed autonomous control method of swarm robot behavior strategy based on artificial immune system and an optimization strategy for artificial immune system. The behavior strategies of swarm robot in the system are depend on the task distribution in environment and we have to consider the dynamics of the system environment. In this paper, the behavior strategies divided into dispersion and aggregation. For applying to artificial immune system, an individual of swarm is regarded as a B-cell, each task distribution in environment as an antigen, a behavior strategy as an antibody and control parameter as a T-cell respectively. The executing process of proposed method is as follows: When the environmental condition changes, the agent selects an appropriate behavior strategy. And its behavior strategy is stimulated and suppressed by other agent using communication. Finally much stimulated strategy is adopted as a swarm behavior strategy. In order to decide more accurately select the behavior strategy, the optimized parameter learning procedure that is represented by stimulus function of antigen to antibody in artificial immune system is required. In this paper, particle swarm optimization algorithm is applied to this learning procedure. The proposed method shows more adaptive and robustness results than the existing system at the viewpoint that the swarm robots learning and adaptation degree associated with the changing of tasks.

• Bulletin of the Korean Chemical Society
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• v.27 no.7
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• pp.1071-1074
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• 2006

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2011.06a
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• pp.1189-1190
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• 2011

• Child Health Nursing Research
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• v.17 no.2
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• pp.91-99
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• 2011

Purpose: This study was done to develop a cell phone addiction prevention program for middle school students, and to examine the effects of the program on self-esteem, self-efficacy, impulsiveness, and cell phone use. Methods: The study was designed using a nonequivalent control group pre-test-post-test design. The participants were 63 middle school students (31 in the experimental group and 32 in the control group). Students in the experimental group were given the cell phone addiction prevention program. The data were analyzed using the SPSS/WIN 14.0 program. Results: Students in the experimental group reported a significant increase in self-esteem compared to students in the control group. Students in the experimental group also reported a significant decrease in cell phone use compared to students in the control group. Conclusion: The results of the study indicate that the cell phone addiction prevention program was effective in increasing self-esteem and decreasing cell phone use in middle school students.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.173-174
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• 2006

Understanding chondrocyte behavior inside complex, three-dimensional environments with controlled patterning of geometrical factors would provide significant insights into the basic biology of tissue regenerations. One of the fundamental limitations in studying such behavior has been the inability to fabricate controlled 3D structures. To overcome this problem, we have developed a three-dimensional microfabrication system. This system allows fabrication of predesigned internal architectures and pore size by stacking up the photopolymerized materials. Photopolymer SL5180 was used as the material for 3D scaffolds. The results demonstrate that controllable and reproducible inner-architecture can be fabricated. Chondrocytes harvested from human nasal septum were cultured in two kinds of 3D scaffolds to observe cell adhesion behavior. Such 3D scaffolds might provide effective key factors to study cell behavior in complex environments and could eventually lead to optimum design of scaffolds in various tissue regenerations such as cartilage, bone, etc. in a near future.

• Biomolecules & Therapeutics
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• v.32 no.3
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• pp.309-318
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• 2024

Compared to other organs, the brain has limited antioxidant defenses. In particular, the hippocampus is the central region for learning and memory and is highly susceptible to oxidative stress. Glial cells are the most abundant cells in the brain, and sustained glial cell activation is critical to the neuroinflammation that aggravates neuropathology and neurotoxicity. Therefore, regulating glial cell activation is a promising neurotherapeutic treatment. Quinic acid (QA) and its derivatives possess anti-oxidant and anti-inflammatory properties. Although previous studies have evidenced QA's benefit on the brain, in vivo and in vitro analyses of its anti-oxidant and anti-inflammatory properties in glial cells have yet to be established. This study investigated QA's rescue effect in lipopolysaccharide (LPS)-induced behavior impairment. Orally administering QA restored social impairment and LPS-induced spatial and fear memory. In addition, QA inhibited proinflammatory mediator, oxidative stress marker, and mitogen-activated protein kinase (MAPK) activation in the LPS-injected hippocampus. QA inhibited nitrite release and extracellular signal-regulated kinase (ERK) phosphorylation in LPS-stimulated astrocytes. Collectively, QA restored impaired neuroinflammation-induced behavior by regulating proinflammatory mediator and ERK activation in astrocytes, demonstrating its potential as a therapeutic agent for neuroinflammation-induced brain disease treatments.

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.223.2-223.2
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• 2015

Polyurethane acrylate (PUA) has been introduced to utilize as a mold material for sub-100 nm lithography as it provides advantages of stiffness for nanostructure formation, short curing time, flexibility for large area replication and transparency for relevant biomedical applications. Due to the ability to fabricate nanostructures on PUA, there have been many efforts to mimic extracellular matrix (ECM) using PUA especially in a field of tissue engineering. It has been demonstrated that PUA is useful for investigating the nanoscale-topographical effects on cell behavior in vitro such as cell attachment, spreading on a substrate, proliferation, and stem cell fate with various types of nanostructures. In this study, we have conducted surface modification of PUA films with micro/nanostructures on their surfaces using plasma treatment. In general, it is widely known that the plasma treated surface increases cell attachment as well as adsorption of ECM materials such as fibronectin, collagen and gelatin. Effect of plasma treatment on PUA especially with surface of micro/nanostructures needs to be understood further for its biomedical applications. We have evaluated the modified PUA film as a culture platform using adipose derived stem cells. Then, the behavior of stem cells and the level of adsorbed protein have been analyzed.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.32 no.8
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• pp.642-653
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• 2008

In this paper, we propose a 3-D finite element (FE) analysis model with combined physical behavior and kinematical impact factors for evaluation of residual stress in multi-impact shot peening. The FE model considers both physical behavior of material and characteristics of kinematical impact. The physical parameters include elastic-plastic FE modeling of shot ball, material damping coefficient, dynamic friction coefficient. The kinematical parameters include impact velocity and diameter of shot ball. Multi-impact FE model consists of 3-D symmetry-cell. We can describe a certain repeated area of peened specimen under equibiaxial residual stress by the cell. With the cell model, we investigate the FE peening coverage, dependency on the impact sequence, effect of repeated cycle. The proposed FE model provides converged and unique solution of surface stress, maximum compressive residual stress and deformation depth at four impact positions. Further, in contrast to the rigid and elastic shots, plastically deformable shot produces residual stresses closer to experimental solutions by X-ray diffraction. Consequently, it is confirmed that the FE model with peening factors and plastic shot is valid for multi-shot peening analyses.