• Korean Journal of Optics and Photonics
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• v.11 no.3
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• pp.163-165
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• 2000

We propose a new structure of optical cross connect based on a WDM MUX/DEMUX pair and switchable mirrors. In experiment, we demonstrate the operation of the optical cross connect using an optical fiber loop mirror connected to a $2\times2$ optical switch as a switchable mirror.mirror.

• The Journal of Advanced Prosthodontics
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• v.8 no.2
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• pp.158-166
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• 2016

PURPOSE. The aim of this study was to determine the fracture resistance and the mode of fracture of endodontically treated teeth restored with different fiber posts and all-ceramic crowns. MATERIALS AND METHODS. Two glass fiber reinforced post systems in two different sizes and polyethylene fiber ribbon in two different thicknesses (n=10) were used. The specimens, restored with all-ceramic crowns, were subjected to a compressive load (in N) delivered at a 130-degree angle to the long axis until a fracture could be noted. The results were analyzed statistically with a One-Way ANOVA test (P<.05). RESULTS. Statistically significant differences were observed between the mean fracture resistance values of Postec, Snowlight, and Kerr Connect thin specimens (P<.0095). The Postec results (395.70 N) were found to be significantly higher than the others. No statistical difference was observed among the thick specimens (P<.2657). The mean fracture resistance values of the Snowlight thick samples were found to be higher than those of the Snowlight thin samples. The specimens were always fractured around the cemento-enamel junction at the palatinal side. No post fracture was observed for the thin Snowlight and Kerr Connect specimens or for the thick Postec and Kerr Connect specimens. Among the common failure types of the specimens, the worst was observed to be the root fracture failure. The highest post dislodgement failure result (80%) was obtained from the thin Kerr Connect specimen. CONCLUSION. In terms of optimizing fracture resistance, the fiber post size selection should be done according to the forces applied to the restored teeth.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.48 no.11
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• pp.889-902
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• 2020

In this study, a numerical analysis was performed to confirm the formation of supersonic flow and the stabilization time satisfying the design condition in a Direct-connect supersonic combustor. The process was examined in which the high-pressure gas of vitiation air heater propagates downstream to the supersonic combustor and forms a supersonic flow field. It was confirmed through the analysis of pressure and temperature that the supersonic flow field satisfies the design points of Mach number 2.0 and 1,000 K, and requires a minimum of 4.0 ms for stabilization. These results indicate that the time required for the supersonic flow field stabilization should be taken into account when testing for the supersonic combustion experiment.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.40 no.8
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• pp.543-548
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• 2003

In this paper, we have proposed and fabricated a two-axis rotational micro-mirror with large tilt angle. Such a micro-mirror is a key element for N$\times$N high capacity optical cross-connect switches. The micro-mirror is required to have large tilt angle to increase the capacity of the cross-connect switches. For larger micro-mirror tilt angle between the grounded mirror plate and the bottom electrode is to be large enough to provide space for the tilting of the mirror. For our proposed structure, the gap was produced in such a way that the grounded mirror plate and the bottom electrode were made separately in different substrates by using the bulk micromachining technology, and combined later by employing self-align technique. As a result, a large tilt angle has been achieved without using additional actuators. The measured tilt angles were as large as $\pm$5.5$^{\circ}$ and $\pm$8.4$^{\circ}$ in the x and y direction respectively, and the pull-in voltages for the two directions were 380 V and 275 V respectively. Finally the fabricated mirror was successfully utilized to steer the optical beam. To our knowledge, our micro-mirror has the best performance among the micro-mirrors reported internationally so far.

• The Journal of the Convergence on Culture Technology
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• v.5 no.3
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• pp.113-118
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• 2019

This study analyzed how interdependence between China, Hong Kong, Taiwan and Singapore stock markets changed after the implementation of Shanghai-Hong Kong Stock Connect system using the EGARCH-GED model that allow simultaneous analysis of return and variability. Since the implementation of this system, the interdependence of Taiwan stock market with the Greater China stock markets has been weakened, and the interdependence of Singapore's stock market with the Greater China stock markets has not been exist. On the other hand, he interdependence between China and Hong Kong stock markets has been shown to be significantly enhanced since the implementation of this system. This is appears to be the result of improved conditions for Chinese and Hong Kong investors to invest in the two stock markets following the implementation of this system. Thus, considering the portfolio investment in the Greater China stock markets, the investors will need to develop their investment strategies in light of these facts that the weakening interdependence of the Taiwan and Singapore securities markets and the strengthening interdependence of the Chinese and Hong Kong securities markets.

• Education of Primary School Mathematics
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• v.26 no.4
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• pp.349-368
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• 2023

The purpose of this study is to explore ways for students to connect conceptual and procedural knowledge in mathematical modeling lessons. Accordingly, we selected the greatest common divisor among the learning contents in which elementary school students have difficulties connecting conceptual and procedural knowledge. A mathematical modeling lesson was designed and implemented to solve problems related to the greatest common divisor while connecting conceptual and procedural knowledge. As a result of the analysis, it was found that the mathematical modeling lesson had positive effects on students solving problems by connecting conceptual and procedural knowledge. In addition, through actual class application, a teaching and learning plan was derived to meaningfully connect conceptual and procedural knowledge in mathematical modeling lessons.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.05a
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• pp.811-812
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• 2011

Recently, because of developments of OS and APP, it requires that one person uses two monitors To improve the productivity of individual. In general, it can connect two monitors to computer. If want more than two, it requires special display-device to connect. In this paper, it describes implementation about device and graphic converting adapter with using USB, which can connect HDMI or DVI, Not like using other expensive hardware before.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.10a
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• pp.511-514
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• 2011

Recently, devices such as smartphone and vehicle blackbox and EDR(Evern Data Recorder knowed automotive real-time control and driving data to use OBD-2(in-vehicle network). when devices receive vehicle driving data, communication way use each Wifi, Bluetooth. but if user and driver change device to use OBD-2 connect, the device differ communication network way. and driver buy and change OBD-2 connect. In this paper, to remedy one's shortcomings, there integrate Bluetooth and Wifi network module and design integrability hardware as any another device know vehicle real-time control and driving data with one integrability connect.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.10
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• pp.5014-5034
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• 2016

This paper discusses how to effectively guarantee the coverage and connectivity quality of wireless sensor networks when joint perception model is used for the nodes whose communication ranges are multi-level adjustable in the absence of position information. A Connect Coverage Algorithm Based on Joint Sensing model (CCAJS) is proposed, with which least working nodes are chosen based on probability model ensuring the coverage quality of the network. The algorithm can balance the position distribution of selected working nodes as far as possible, as well as reduce the overall energy consumption of the whole network. The simulation results show that, less working nodes are needed to ensure the coverage quality of networks using joint perception model than using the binary perception model. CCAJS can not only satisfy expected coverage quality and connectivity, but also decrease the energy consumption, thereby prolonging the network lifetime.

• Journal of IKEEE
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• v.25 no.3
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• pp.493-500
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• 2021

In this paper, we propose the development of deep learning structure to improve quality of polygonal containers. The deep learning structure consists of a convolution layer, a bottleneck layer, a fully connect layer, and a softmax layer. The convolution layer is a layer that obtains a feature image by performing a convolution 3x3 operation on the input image or the feature image of the previous layer with several feature filters. The bottleneck layer selects only the optimal features among the features on the feature image extracted through the convolution layer, reduces the channel to a convolution 1x1 ReLU, and performs a convolution 3x3 ReLU. The global average pooling operation performed after going through the bottleneck layer reduces the size of the feature image by selecting only the optimal features among the features of the feature image extracted through the convolution layer. The fully connect layer outputs the output data through 6 fully connect layers. The softmax layer multiplies and multiplies the value between the value of the input layer node and the target node to be calculated, and converts it into a value between 0 and 1 through an activation function. After the learning is completed, the recognition process classifies non-circular glass bottles by performing image acquisition using a camera, measuring position detection, and non-circular glass bottle classification using deep learning as in the learning process. In order to evaluate the performance of the deep learning structure to improve quality of polygonal containers, as a result of an experiment at an authorized testing institute, it was calculated to be at the same level as the world's highest level with 99% good/defective discrimination accuracy. Inspection time averaged 1.7 seconds, which was calculated within the operating time standards of production processes using non-circular machine vision systems. Therefore, the effectiveness of the performance of the deep learning structure to improve quality of polygonal containers proposed in this paper was proven.