• Molecules and Cells
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• v.37 no.6
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• pp.497-502
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• 2014

Microfluidics can provide unique experimental tools to visualize the development of neural structures within a microscale device, which is followed by guidance of neurite growth in the axonal isolation compartment. We utilized microfluidics technology to monitor the differentiation and migration of neural cells derived from human embryonic stem cells (hESCs). We co-cultured hESCs with PA6 stromal cells, and isolated neural rosette-like structures, which subsequently formed neurospheres in suspension culture. Tuj1-positive neural cells, but not nestin-positive neural precursor cells (NPCs), were able to enter the microfluidics grooves (microchannels), suggesting that neural cell-migratory capacity was dependent upon neuronal differentiation stage. We also showed that bundles of axons formed and extended into the microchannels. Taken together, these results demonstrated that microfluidics technology can provide useful tools to study neurite outgrowth and axon guidance of neural cells, which are derived from human embryonic stem cells.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.1
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• pp.63-68
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• 2019

Emerging applications such as Smart factory, in-car network, wide area power network require strict bounds on the end-to-end network delays. Flow-based scheduler in traditional Integrated Services (IntServ) architecture could be possible solution, yet its complexity prohibits practical implementation. Sub-optimal class-based scheduler cannot provide guaranteed delay since the burst increases rapidly as nodes are passed by. Therefore a leaky-bucket type regulator placed next to the scheduler is being considered widely. This paper proposes a simple server that achieves both fair scheduling and traffic regulation at the same time. The performance of the proposed server is investigated, and it is shown that a few msec delay bound can be achieved even in large scale networks.

• Journal of Digital Convergence
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• v.11 no.2
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• pp.299-307
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• 2013

The aim of this paper is the improvement of identification performance and the reduction of computational quantities in the face recognition system based on SIFT-Grid. Firstly, we propose a composition method of integrated template by removing similar SIFT keypoints and blending different keypoints in variety training images of one face class. The integrated template is made up of computation of similarity matrix and threshold-based histogram from keypoints in a same sub-region which divided by applying SIFT-Grid of training images. Secondly, we propose a computation method of similarity for identify of test image from composed integrated templates efficiently. The computation of similarity is performed that a test image to compare one-on-one with the integrated template of each face class. Then, a similarity score and a threshold-voting score calculates according to each sub-region. In the experimental results of face recognition tasks, the proposed methods is founded to be more accurate than both two other methods based on SIFT-Grid, also the computational quantities are reduce.

• Journal of Engineering Education Research
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• v.18 no.2
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• pp.77-88
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• 2015

Recently, there has been an increasing interest in 'Flipped Learning,' an IT-based learner-centered teaching-learning method corresponding to meet the paradigm of the future education. For smooth Flipped Learning, there are three steps in total: a pre-class should precede; then, in the structure of classes in the classroom, in-class learning among peer learners should be done; and lastly, the operation of a post-class should be done. For successful Flipped Learning, class elements in each step should be designed with a time difference, interconnected so as to achieve a single educational objective. However, it was found that there was a limitation in that the teaching-learning model of the preceding Flipped Learning consisted of the order of analysis, design, development, implementation and evaluation as general procedures, so it would not sufficiently consider the situations of Flipped Learning only. On this background, this thesis proposes a differentiated Flipped Learning model for mastery learning in a subject of an institute of technology as a model of systematic instructional design and presents a case of a class applied to an actual subject of computer engineering.

• Korean Journal of Clinical Laboratory Science
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• v.50 no.2
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• pp.164-169
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• 2018

The development of teaching models to strengthen practical education and actively participate in the classes of students is now required in recent education situations. This study examined the participation and satisfaction level of students' classes after applying a teaching model-integrated hospital and school laboratory (named L2L). A total of 33 students who took the subject of a clinical microbiology experiments were involved in this study. Each group representative participating in a pre-class field exercise in the hospital microbiology laboratory was asked to conduct the experiment. After applying the L2L teaching models, the academic self-efficacy ($2.87{\pm}0.58{\rightarrow}3.38{\pm}0.55$), class participation ($2.60{\pm}0.92{\rightarrow}3.62{\pm}0.78$), and class satisfaction ($2.48{\pm}1.01{\rightarrow}3.85{\pm}0.87$) increased significantly (P<0.05). This means that pre-class field exercises created interest in the student's class and boosted self-confidence, leading to increased participation and satisfaction for the class. In conclusion, the L2L teaching model is an effective teaching method to enhance the practical training for preliminary clinical laboratory technologists.

• Proceedings of the KIEE Conference
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• 2002.07b
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• pp.1193-1195
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• 2002

This paper presents Active-clamp Class-E high frequency resonant inverter with single-stage. The proposed circuit is integrated Active-c class-E circuit to boost converter with the funct power factor correction. Boost converter is opera positive and negative half cycle respectively at frequency(60Hz), operating in Discontinuous Con Mode(DCM) of boost converter performs high p factor. By adding active-clamp circuit in Cl inverter, main switch of inverter part is operat only ZVS(Zero Voltage Switch), but also reduce switching voltage stress of main switch. Simulation result using Psim4.1 show that the p prove the validity of theoretical analysis. This proposed inverter will be able to be pract used as a power supply in various fields are ind heating applications, DC-DC converter etc.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2002.11a
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• pp.287-291
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• 2002

This paper presents active-clamp class-E high frequency resonant inverter with single-stage. The proposed circuit is integrated active-clamp class-E circuit to boost converter with the function of power factor correction. Boost converter is operated in positive and negative half cycle respectively at line frequency(60Hz), Such a operating in discontinuous conduction mode(DCM) of boost converter performs high power factor. By adding active-clamp circuit in class-E inverter, main switch of inverter part is operated not only ZVS(Zero Voltage Switch) but also reduced the switching voltage stress of main switch. This paper shows that simulation result using Psim 4.1 prove the validity of theoretical analysis. This proposed inverter will be able to be practically used as a power supply in various fields as induction heating applications, DC-DC converter etc.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.54 no.1
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• pp.53-57
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• 2005

When concurrency is integrated to programming language, problem more than inheritance remains yet. Because more than inheritance happens by collision or cross fire between synchronization and inheritance of same time object, when synchronization code is not detached properly from method code about same time object, it makes expanded of code to make derivation class change synchronization code of super class and method code. In this paper, minimize right of inheritance method, When subclass is introduced to new synchronization limitation condition, wish to solve problem more than inheritance of three types that happen in same time programming embodying C++ class that do so that can avoid alteration of method reed.

• JSTS:Journal of Semiconductor Technology and Science
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• v.7 no.4
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• pp.274-280
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• 2007

This paper demonstrates an efficiency improvement of the class E power amplifier (PA) by tuning-out the input capacitance ($C_{IN}$) of the power HBT with a shunt inductance. In order to obtain high output power, the PA needs the large emitter size of a transistor. The larger the emitter size, the higher the parasitic capacitance. The parasitic $C_{IN}$ affects the distortion of the voltage signal at the base node and changes the duty cycle to decrease the PA's efficiency. Adopting the L-C resonance, we obtain a remarkable efficiency improvement of as much as 7%. This PA exhibits output power of 29 dBm and collector efficiency of 71% at 1.9 GHz.

• Journal of Internet Computing and Services
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• v.7 no.5
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• pp.123-134
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• 2006

In this research paper, We have proposed an interpretation structure concerned with context-awareness which is essential to provide intelligent service. The proposed model has an interpretation structure that integrated information of both external and internal context, and been designed to keep independency between context information and application service. To verify the interpretation structure that proposed, we established a test bed (Ubi-Class) in which the concept of context awareness has been introduced to the existing class room, and constituted a scenario, and tested whether intelligent service is performed according to context interpretation.