• Journal of The Korean Association of Information Education
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• v.14 no.3
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• pp.395-404
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• 2010

One of the object on math education is low-level students. To improve this problem and to instruct efficiently I developed "let's play figures" instruction and learning system. This system reconstructed diagram part of math into 5steps to achieve the goal of tailored education to fit student's learning level. Based on this, the game can be used as the teaching method to enhance the student's interest and self-studying ability and also this system has been developed for the education connected to home.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.8
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• pp.3-12
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• 2016

Bluetooth Low Energy (BLE) protocol has attracted attention as a promising technology for low data throughput and low energy wireless sensor networks. Fast device discovery is very important in a BLE based wireless network. It is necessary to configure the network to work with minimized energy consumption because the BLE network nodes are expected to operate a long time typically on a coin cell battery. However, since it is difficult to obtain low energy and low latency at the same time, the BLE standard introduces wide range setting of parameters related to device discovery process and let the network operators to set up parameter values for the application. Therefore, it is necessary to analyze the performance of device discovery according to the related parameter values prior to BLE network operation. In this paper we analyze the expected value and the cumulative distribution function of the number of advertisements for device discovery in the BLE network. In addition, we propose a scheme for controlling the interval between advertising events that can improve the performance of device discovery without increasing energy consumption.

• The Journal of the Korea Contents Association
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• v.14 no.6
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• pp.162-173
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• 2014

Among OECD countries, Korea is the only country which has continuously recorded total birthrate below 1.3 person for over 10 years. Since 2006, the Korean government has promoted the population policy in full scale. But, the fertility rate which became low has not shown any sign to go up again. Thus, Korea can be understood as having fallen into 'low fertility trap'. Such a low fertility can cause serious problems such as weakening of national competitive power and even survival of the country. In Korea, due to studies and finding jobs among young women, their childbirths are kept being postponed. In some cases, poor working conditions where women work can cause physical conditions not appropriate for pregnancy. Thus, it is very important to let childbearing women, pregnant women take care of their health. Accordingly, conscious of this low fertility era, this study examined major international organizations and countries' health promoting strategies-with focus on motherhood and suggested some methods to effectively improve health for motherhood.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.03a
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• pp.21-21
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• 2010

(Ba,Sr)$TiO_3$ (BST) thin film with a perovskite structure has potential for the practical application in various functional devices such as nonvolatile-memory components, capacitor, gate insulator of thin-film transistors, and electro-optic devices for display. Normally, the BST thin films derived from sol-gel and sputtering are amorphous or partially crystalline when processed below $600^{\circ}C$. For the purpose of integrating BST thin film directly into a Si-based read-out integrated circuit (ROIC), it is necessary to process the BST film below $400^{\circ}C$. The microstructural and electrical properties of low-temperature crystallized BST film were studied. The BST thin films have been fabricated at $350^{\circ}C$ by UV-assisted rapidly thermal annealing (RTA). The BST films are in a single perovskite phase and have well-defined electrical properties such as high dielectric constant, low dielectric loss, low leakage current density, and high breakdown voltage. Photoexcitation of the organics contained in the sol-gel-derived films by high-intensity UV irradiation facilitates elimination of the organics and formation of the single-crystalline phase films at low temperatures. The amorphous BST thin film was transformed to a highly (h00)-oriented perovskite structure by high oxygen pressure processing (HOPP) at as low as $350^{\circ}C$. The dielectric properties of BST film were comparable to (or even better than) those of the conventionally processed BST films prepared by sputtering or post-annealing at temperature above $600^{\circ}C$. When external pressure was applied to the well-known contractive BST system during annealing, the nucleation energy barrier was reduced; correspondingly, the crystallization temperature decreased. The UV-assisted RTA and HOPP, as compatible with existing MOS technology, let the BST films be integrated into radio-frequency circuit and mixed-signal integrated circuit below the critical temperature of $400^{\circ}C$.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.41 no.1
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• pp.79-84
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• 2013

DC/DC switching power converters are commonly used to generate a regulated DC output voltage with high efficiency. The DC/DC converter is composed of a PWM-IC (pulse width modulation-integrated circuit) controller, a MOSFET (metal-oxide semiconductor field effect transistor), inductor, capacitor, etc. It is shown that the variation of threshold voltage and the offset voltage in the electrical characteristics of PWM-IC increase by radiation effects in TID (Total Ionizing Dose) testing at the low energy ${\gamma}$ rays using $^{60}Co$, and 4 heavy ions applied for SEL (Single Event Latch-up) make the PWM pulse unstable. Also, the output waveform for the given input in the DC/DC converter is observed by the simulation program with integrated circuit emphasis (SPICE). TID testing on PWM-IC is accomplished up to the total dose of 30 krad, and the cross section($cm^2$) versus LET($MeV/mg/cm^2$) in the PWM operation is studied at SEL testing after implementation of the controller board.

• Korean Journal of Applied Biomechanics
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• v.16 no.3
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• pp.173-181
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• 2006

The purpose of this study is grasp the problem of the gymnast, Kim, Dong-Hwa's Kip to Swallow Motion in Rings, and make up for the weak points to help him to perform a better performance. Therefore, two tryouts for $28^{th}$ Athens Olympic Games were filmed using video camera then finalized with Kinematical Analysis using 3D motion analysis program followings are the form of conclusions. 1. In the very first tryout, when he was doing a Swallow Support Scale, his CM position was high and arm slope was deduction because when he was doing Kip, the ascent velocity was low and he tried excessively to pull him on rings due to relying upon angular movement of shoulder joint. 2. When he was doing drop, he let his hip angle bend only little bit and let fall so making shoulder angle wider and maintain the level horizontally occurs strong drop motion when vertical descent is happening. 3. As a result, lowering the direction of a kick makes CM's movement path lower, increase vertical ascent velocity, and it helps to do the Swallow Support motion in short period of time. 4. After a strong drop motion, which is deep and fast, would make rope of ring shake so there is a defect that the body moves to forward area. However, it does not effect in Swallow Support Scale motion. 5. In the second tryout, trunk rotation angle and arm slope was fixed decrease while doing rotary motion. When rotary motion was happening, before the body was going under the rings, maintained his arm slope horizontally so his Swallow Support Scale motion was nearly perfect.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.42 no.11
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• pp.981-987
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• 2014

DC/DC switching power converters are commonly used to generate a regulated DC output voltage with high efficiency. The DC/DC converter is composed of a MOSFET (metal-oxide semiconductor field effect transistor), a PWM-IC (pulse width modulation-integrated circuit) controller, inductor, capacitor, etc. It is shown that the variation of threshold voltage and the breakdown voltage in the electrical characteristics of MOSFET occurs by radiation effects in TID (Total Ionizing Dose) testing at the low energy ${\gamma}$ rays using $^{60}Co$, and 5 heavy ions make the gate of MOSFET broken in SEGR (Single Event Gate Rupture) testing. TID testing on MOSFET is accomplished up to the total dose of 40 krad, and the cross section($cm^2$) versus LET(MeV/mg/$cm^2$) in the MOSFET operation is studied at SEGR testing after implementation of the controller board.

• Journal of the Korea Society of Computer and Information
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• v.25 no.7
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• pp.65-73
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• 2020

Viral video advertising is being used in the advertising and film industry for pre-promotion of certain products or pre-release films which has a lot of effect on investment. An analysis of viral video recognition is needed to predict future development directions. In response, the study conducted a survey on viral videos, focusing on college students in their 20s, who are the most exposed to advertisements and movies. Through this, the survey was conducted on recognition of viral videos, memorable viral videos, satisfaction level, message propagation method, positiveness of viral videos, expected future development, and desired viral video type. The survey showed that viral video recognition was 16.7% and the most memorable viral video; the "Let it Go" viral video from the movie "Frozen" was 69.1 %, according to the survey. The satisfaction level was not high at 31.2 %, and 73.5% of people sent messages to others after watching viral videos, which was very high. Negative opinions on viral videos were low at 13.7 %. 64.5% of the surveyors said the future of the viral videos would "develop" and 6.7% said would "not develop."

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.7
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• pp.36-41
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• 2018

An image intensifying device is equipment that makes weak objects visible in a dark environment, such as making nighttime bright enough to let objects be visually observed. It is possible to obtain a clear image by amplifying the light in the presence of a certain amount of weak light. However, in an extremely low-light environment, where even moonlight is not present, there is not enough light to amplify anything, and the sharpness of the screen deteriorates. In this paper, a method is proposed to improve image quality by using multiple filters and anisotropic diffusion for output noise of the image-intensifying device in extreme low-light environments. For the experiment, the output of the image-intensifying device was obtained under extremely low-light conditions, and signal processing for improving the image quality was performed. The configuration of the filters for signal processing uses anisotropic diffusion after applying a median filter and a Wiener filter for effective removal of salt-and-pepper noise and Gaussian noise, which constitute the main noise appearing in the image. Experimental results show that the improvement visually enhanced image quality. Both peak signal-to-noise ratio (PSNR) and SSIM, which are quantitative indicators, show improved values.

• Journal of Forest and Environmental Science
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• v.25 no.2
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• pp.131-138
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• 2009

Recently, various efforts for the extended utilization of woody biomass has been attempted due to the fact that global warming, energy and environmental problems are urgent ones to be solved. Development of new energy sources at our national security level is desperately needed as we depend on almost all of energies supplied from other countries, let alone the economic crisis caused by oil price hike. Woody biomass can be converted to energy by means of thermochemical, biological, or direct combustion processes. Many processes are available for producing bioenergy, such as bioethanol, wood pellet, wood chip, combined heat, and power system. Political support and R&D investment should be provided that can boost the utilization of the wood biomass, the eco-environment, and recyclable and alternative energy resources for national power security. In addition, a long-term strategy that can utilize unused and low efficient woody biomass resources, and systematically collect and manage them in a national level should be set up. Even though the possibility in total exchange of fossil oil with woody biomass is quite low, technology developments of woody biomass for the solution to global warming and environmental problem through its commercialization are expected to grow steadily.