• The Korean Journal of Physiology and Pharmacology
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• 제1권2호
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• pp.117-125
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• 1997

The N-methyl-D-aspartate (NMDA) receptor-mediated glutamatergic neurotransmission is involved in synaptic plasticity, developmental processes, learning and memory and many neuropathological disorders including age-related diseases. In the present study, regulation of the NMDA receptor properties by various ligands was investigated using $[^3H]MK-801$ binding studies in the synaptic membranes of young and aged rat forebrains. The binding in the presence of glutamate and glycine increased dramatically with growth between 1 and 6 weeks old, and thereafter declined gradually with aging. Glutamate, glycine or spermine respectively increased the binding with growth. Glutamate maintained the binding during aging, while glycine or spermine significantly decreased the binding in the aged brain. The maximum stimulation by glycine varied depending on the ages of brains. Greater sensitivity to glycine was observed at 1 week and 3 months and the sensitivity was significantly reduced in the aged brain. In contrast, spermine showed similar stimulation patterns in young and aged rats. These results indicated that the functional properties of the NMDA receptor-ion channel complex in young and aged rat forebrains are differentially regulated by agonists, and the reduction of the receptor function with normal aging may be, in some degree, due to the reduction of the receptor sensitivity to glycine.

• Wind and Structures
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• 제25권1호
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• pp.25-38
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• 2017

This study investigates the dynamic analysis of a transversely isotropic thin plate. The plate is made of hyperelastic John's material and its constitutive law is obtained by taken the Frechect derivative of the highlighted energy function with respect to the geometry of deformation. The three-dimensional equation governing the motion of the plate is expressed in terms of first Piola-Kirchhoff's stress tensor. In the reduction to an equivalent two-dimensional plate equation, the obtained model generalizes the classical plate equation of motion. It is obtained that the plate under consideration exhibits harmonic force within its planes whereas this force varnishes in the classical plate model. The presence of harmonic forces within the planes of the considered plate increases the natural and resonance frequencies of the plate in free and forced vibrations respectively. Further, the parameter characterizing the transversely isotropic structure of the plate is observed to increase the plate flexural rigidity which in turn increases both the natural and resonance frequencies. Finally, this study reinforces the view that non-classical models of problems in elasticity provide ample opportunity to reveal important phenomena which classical models often fail to apprehend.

• Biomolecules & Therapeutics
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• 제18권1호
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• pp.24-31
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• 2010

Taurine, 2-aminoethanesulfonic acid, is an abundant free amino acid present in brain cells and exerts many important biological functions such as anti-convulsant, modulation of neuronal excitability, regulation of learning and memory, anti-aggressiveness and anti-alcoholic effects. In the present study, we investigated to explore whether taurine has any protective actions against oxidative stress-induced damages in neuronal cells. ERK I/II regulates signaling pathways involved in nitric oxide (NO) and reactive oxygen species (ROS) production and plays a role in the regulation of cell growth, and apoptosis. We have found that taurine significantly inhibited AMPA induced cortical depolarization in the Grease Gap assays using rat cortical slices. Taurine also inhibited AMPA-induced neuronal cell damage in MTT assays in the differentiated SH-SY5Y cells. When the neuronal cells were treated with $H_2O_2$, levels of NO were increased; however, taurine pretreatment decreased the NO production induced by $H_2O_2$ to approximately normal levels. Interestingly, taurine treatment stimulated ERK I/II activity in the presence of AMPA or $H_2O_2$, suggesting the potential role of ERK I/II in the neuroprotection of taurine. Taken together, taurine has significant neuroprotective actions against AMPA or $H_2O_2$ induced damages in neuronal cells, possibly via activation of ERK I/II.

• 통상정보연구
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• 제12권4호
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• pp.363-382
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• 2010

It should be unthinkable to not provide water at survival of any living things. Water is too a basic element for development for a country. Currently, the global market of mineral water is growing rapidly. This study, I conceptualized mineral water as bottled water. In particularly, bottled water has seen huge global growth for the last few years. The annual growth rate of the market in the period 2005-2009 was 5.9%. Following a surge in obesity and subsequent health and wellness trends, many consumers are switching from sugary soft drinks to healthier alternatives. Therefore, the global bottled water market is one area which has big potential for growth, but price competition is getting intensified among multi-national and domestic firms. Korean providers too are faced with strong competition in growing domestic market. The bottled water market has presence of multinational provider like Nestle, Danone and Coca-Cola, which collectively account for 35.1% of the world market share in 2009. On the basis of a market orientation approach, this article looks at changing environments in the world mineral water industry and attempts to describe foreign market entry strategy of the Korean mineral water industry. The market orientation provides strong norms for learning from customers and competitors, is instrumental in creating a superior value for buyers, innovating successfully, and generating excellent firm performance. So firms should consider a strategic planning in basis on market orientation before they enter foreign markets. Some discussions were made about managerial implications for Korean bottled water providers.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1994년도 추계학술대회 논문집
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• pp.266-272
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• 1994

An essential ingredient in precision machining is a positioning system that responds quickly and precisely to very small input signal. In this paper, two different positioning systems were presented fot the precision positioning control. The one is a friction drive system, the other is a ballscrew system. The friction drive system was composed of an air sliding guide and a friction drive. The ballscrew system was made of a ballscrew and a linear guide. Nonlinear behaviors of the given systems tend to make the system inaccurate. The paper looked at the phenomena that has caused the positioning error. These apparently nonlinear phenomena can be attributed mainly to the presence of the nonlinear friction and slip effect plus the dynamic change from the microdynamic to the macrodynamic and form the macrodynamic to the microdynamic. For the control of the positioning system, the control algorithm based on a neural network is suggested. The FEL(Feedback Error Learning) controller can learn the inverse dynamics of a nonlinear system by using the neural network controller, and stabilize the system by a linear controller. In the experiment, PTP control is implemented withen the maximum error of 0.05 .mu.m ~0.1 .mu. m when i .mu.m step reference input is applied and that of maximum 1 .mu. m when 100 .mu.m step reference input is given. Sinusoidal inputs with the amplitude of 1 .mu.m and 100 .mu. m are used for the tracking control of the positioning system. Experimental results of the proposed algorithm are shown to be superior to those of conventional PD controls.

• 한국초등과학교육학회지:초등과학교육
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• 제27권3호
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• pp.244-251
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• 2008

One of the problems with testing for the presence of $CO_2$ is that the results are not visible. In order to over-come this weak point, a new testing method was developed with BTB indicator equipment, that made the gas visible. After that, the experiment was performed and tested the effects of the new visible equipment. The visible equipment could be adapted to regular class use successfully. Also, it was effective in that it reduced waste of gas, minimized danger potential through use of $CO_2$ canisters and candle-sticks, and also increased knowledge about indicators. The new experimental method and equipment affected the students' interest. It is possible that the students' positive participation was due to their interest in the new apparatus and application of the visual senses. The new system was tested fer its effects on teaching content and helping to produce sustained memory of the content. There were no significant differences between the groups in terms of content learning on initial content memory. However, when students in both groups were tested 4 months later, the visual experiment group sustained memory performance, while the other group showed a significant decrease. Generally, boys score higher than girls in terms of interest and participation in experimental activities. In this case, however, there were no difference between groups. It may have been due to introduction of new equipment and different methods from the textbooks. So, this could increase participation in science using various experiments.

• 센서학회지
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• 제29권3호
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• pp.194-200
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• 2020

Human detection is an important aspect in many video-based sensing and monitoring systems. Studies have been actively conducted for the automatic detection of humans in camera images, and various methods have been proposed. However, there are still problems in terms of performance and computational cost. In this paper, we describe a method for efficient human detection in the field of view of a camera, which may be static or moving, through multiple processing steps. A detection line is designated at the position where a human appears first in a sensing area, and only the one-dimensional gray pixel values of the line are monitored. If any noticeable change occurs in the detection line, corner detection and optical flow computation are performed in the vicinity of the detection line to confirm the change. When significant changes are observed in the corner numbers and optical flow vectors, the final determination of human presence in the monitoring area is performed using the Histograms of Oriented Gradients method and a Support Vector Machine. The proposed method requires processing only specific small areas of two consecutive gray images. Furthermore, this method enables operation not only in a static condition with a fixed camera, but also in a dynamic condition such as an operation using a camera attached to a moving vehicle.

• 한국항공운항학회지
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• 제22권4호
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• pp.42-55
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• 2014

The purpose of this research was to identify expertise in ait traffic control by using cognitive skill analysis for novices and experts in routine and non-routine situations. The result of study was to understand expertise in air traffic control tasks in terms of what cognitive processes are responsible for the expert's high performance levels. The problem solving task was difficult for novices, but performed relatively automatically by experts in a routine situation. The difficulty could indicate the presence of controlled processing. Rather than rules and strategies, novices focused more on environmental factors, which merely increase cognitive load. In a non-routine situation, novices showed that they did not categorize the information consistently and alternative resources were not available for them. Experts, however, performed automatically a task by arranging and organizing information related to problem solving components in contexts without regard to a routine and non-routine situation. Especially experts developed a stable representation and directed alternative resources for air traffic flow and efficiency. Based on the results, cognitive processes of experts could be useful to understand expert performance and analyze the learning process, which imply the necessity of developing expertise systematically.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2004년도 춘계종합학술대회
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• pp.608-611
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• 2004

본 논문에서는 고유얼굴 특성에 기반한 강건한 얼굴 인식 기술을 제안한다. 전형적인 고유얼굴 인식방법은 학습영역에서 고유얼굴을 생성시키고, 모든 학습영상을 이 얼굴공간에 투영시켜 각각의 사람마다 저장된 성분들을 비교하거나 상관시켜 특징들을 추출합니다. 복잡한 배경에 있는 얼굴들을 인식할 때 EFR방법은 얼굴인식에는 강하지만, 얼굴과 배경들 사이의 구분을 실패하게 된다 배경에서 강건한 얼굴인식을 위해서 배경패턴을 학습하며, 배경영역은 배경패턴으로부터 생성되어 얼굴영역과 함께 얼굴 인식을 위하여 사용된다. 본 논문에서 제안한 방법이 EFR방법보다 성능과 복잡한 배경하에서 매우 좋은 결과를 나타냄을 확인할 수 있었다.

• 복식문화연구
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• 제27권1호
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• pp.72-80
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• 2019

A teaching manual was developed to incorporate the creative problem solving process into a fashion marking course. Students' creativity, problem solving, critical thinking, and analytical thinking are promoted by applying the creative problem solving process systematically to solve authentic business problems experienced by local apparel business owners. This teaching manual is based on the FourSight Model that consists of Clarify, Ideate, Develop, and Implement. Various tools promoting divergent thinking are also utilized in the process. A local fashion business is invited as a problem owner and four resource groups are formed with students based on the results of the Kirton Adaption Innovation Inventory. Each resource group consists of 6-8 students. The creative problem solving process is implemented into a classroom setting as four 75-minutes sessions that are held twice a week for two consecutive weeks. The local fashion business owner will be in presence during the first (Clarify) and last (Implement) sessions. The instructor facilitator meets with the problem owner outside the classroom three times including pre-session client interview, after the second (Ideate) session, and before the third (Develop) session. This modified CPS manual for fashion marketing and merchandising courses provides practical guidelines to work with local fashion businesses while providing students with learning opportunities of the creative problem solving process.