• 한국정보교육학회:학술대회논문집
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• 2007.01a
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• pp.281-286
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• 2007

최근 디지털 맵이나 GIS와 같은 새로운 테크놀로지의 발달로 사회과 지리영역은 많은 변화가 요구되고 있다. 특히 교육방법적 측면에서 학생들의 흥미를 북돋워줄 수 있는 교수학습 방법의 개발과 적용이 필요하다. 그러나 기존의 시청각매체는 학생들의 흥미를 만족시켜주는데 한계가 있을 뿐만 아니라 최신의 자료가 반영되지 못한 경우가 많다. 요즘에는 인터넷의 발달로 지구상에서 일어나는 일을 쉽고 빠르게 찾아볼 수 있으며 구글 어스 등의 새로운 GIS를 활용하여 세계의 모습을 정확하고 손쉽게 볼 수 있다. 그러나 아직까지 교육과정에서 GIS를 활용하는 것에 관한 연구는 부족한 편이다. 이에 교육과정에서 활용할 수 있는 디지털 맵과 GIS를 조사하고, 이를 수업현장에서 활용할 수 있는 수업모형을 제안하고자 한다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.5
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• pp.879-886
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• 2003

Agile frequency synthesizers are the common device used for commandable, wide-band frequency hopping in frequency-hopped (FH) communications. In this paper, synthesizer phase transient effect and its compensation methods in an FH/FSK(Frequency Hopped Frequency Shift Keying) system are studied. Models for these analysis are developed and resulting performance degradations are computed. The basic PLL is difficult to implement for fast frequency hopping in narrowband radio communication systems. To solve this problem, digital frequency synthesizer/CPM (Continuous Phase Modulation)modulator is proposed. And it's performance is analyzed theoretically. The analysis show that fast frequency hopping is possible in frequency hopping system that use digital frequency synthesizer/CPM modulator.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.49 no.7
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• pp.23-29
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• 2012

The LC-based digitally controlled oscillator (LC-DCO), a key component of the all digital phase locked loop (ADPLL), is designed using $0.18{\mu}m$ RFCMOS process with 1.8 V supply. The NMOS core with double cross-coupled pair is chosen to realize wide tuning range, and the PMOS varactor pair that has small capacitance of a few aF and the capacitive degeneration technique to shrink the capacitive element are adopted to obtain the high frequency resolution. Also, the noise filtering technique is used to improve phase noise performance. Measurement results show the center frequency of 2.7 GHz, the tuning range of 2.5 GHz and the high frequency resolution of 2.9 kHz ~7.1 kHz. Also the fine tuning range and the current consumption of the core could be controlled by using the array of PMOS transistors using current biasing. The current consumption is between 17 mA and 26 mA at 1.8V supply voltage. The proposed DCO could be used widely in various communication system.

• Cartoon and Animation Studies
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• s.45
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• pp.215-233
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• 2016

Timelapse which was appeared Georges Mellieoseu in 1897 was not familiar to people and was not popular in film or broadcast industry in spite of long history. But about 5 years ago, timelapse has become distinguished in all around image art, because it show us aesthetic extraction of time and variation of color in Vimeo and Youtube which neve been seen before. So nowadays latest camera has come out with default menu which can shoot timelapse. But popularity of timelapse seem not development of cinematography technique or appearance of new function but production of image which reflects ages of present with fully accept digital media property. This study is approached from two formative characteristics. First it is strengthen of time which is showed timelapse and analog media from a comparison angle. Second, it is how to extend their sense and imitate images through resolution which can be possible high quality image and color especially with Raw data Through these methodology, this study defines correlation of character of digital media and artistic value of images in timelapse. And also it cleary assures the era of penetrating art has not only visual amusement as known but, also representative value of our ages and technology of media.

• Journal of Advanced Navigation Technology
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• v.13 no.3
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• pp.358-364
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• 2009

This paper shows some variable bias techniques which can improve the power added efficiency(PAE) for the designed power amplifier. Some simulations have been done to get the effect of the bias change, and variable bias is adopted to get the higher efficiency for dual mode amplifier which generates two different output power levels. With drain bias change and a fixed gate bias, the amplifier shows PAE improvement compared to the fixed bias amplifier. In addition, this paper analyzed nonlinear distortion of the power amplifier and has used the digital predistortion which can result in 10dB ACPR improvement for the dual band amplifier.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.5
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• pp.863-871
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• 2003

In this paper, we design a high stable Ku-band phase-locked dielectric resonant microwave oscillator with the gate voltage controls of p-HEMT. By adapting the nonlinear equivalent elements which affects phase noise of microwave oscillator, we optimize the nonlinear elements of p-HEMT to have low phase noise operation. Using the scattering parameters according to bias voltages, we designed the gate voltage control microwave dielectric resonant oscillator and phase-locked loop circuits is applied to have the high stable operations. Designed microwave oscillator as a local oscillator of digital microwave communication shows that output power is 9.17dBm at 10.75GHz and it's phase noise is -88dBc/Hz at 10KHz offset frequency.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.9
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• pp.2161-2168
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• 2014

According to the growing interest in the digital convergence throughout society, the convergence of creative and new forms is emerging recently in various fields. Research methods to explore the diversity of academic studies have been studied in the field of study. As one of these methods, research on electronic cultural atlas that has features of convergence studies is gradually spreading. In this paper, we examine existing electronic cultural atlas and then, compare and analyze them. In details, existing electronic cultural atlas are comparative analyzed on the basis of base map, interface, and function. Through the results of comparative analysis, the efficient production of electronic cultural atlas are examined.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.1
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• pp.18-27
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• 2004

In this paper, we presents an analytical simulation procedure for evaluation in baseband digital modulated signals distortions in the present of RF power amplifier(SSPA) nonlinear behavior and backoff operations of OFDM wireless transmission system. we obtained the optimum nonlinear transfer function of designed SSPA with the SiGe HBT bias currents of OFDM multi-channel wireless transmission system and compared this transfer function to SSPA nonlinear modeling functions mathematically, we finds optimum bias conditions of designed SSPA. With the derived nonlinear modeling function of SSPA, We analysed the PSD characteristics of in-band and out-band output powers of SSPA EVM measurement results of distorted constellation signals with the input power levels of SSPA. The results of paper can be applied to find the SSPA linearly with optimum bias currents and determine the SSPA input backoff bias for AGC control circuits of SSPA.

• Journal of Digital Convergence
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• v.17 no.3
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• pp.205-213
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• 2019

In a construction site, excavation work has a close relation with temporary earth retaining structure. In order to build the underground structure most effectively in a narrow space, prevent soil relaxation of the external behind ground in excavation work, and maintain a ground water level, it is required to install a temporary earth retaining structure that secures safety. To prevent soil washoff in underground excavation work, the conventional method of temporary earth retaining structure is to make a temporary wall and build the internal support with the use of earth anchor, raker, and struct for excavation work. RSB method that improves the problem of the conventional method is to remove the internal support, make use of two-row soldier piles and bracing, and thereby to resist earth pressure independently for underground excavation. This study revealed that through the field application cases of RSB method and the measurement result, the applicability of the method for installing a temporary earth retaining structure, the assessment result, and displacement all met allowable values of measurement, and that the RSB method, compared to the conventional method, improved constructability and economy.

• Knowledge Management Research
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• v.23 no.2
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• pp.123-142
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• 2022

The non-face-to-face environment accelerated by COVID-19 has speeded up the dissemination of digital virtual ecosystems and metaverse. In order for the metaverse to be sustainable, digital twins that are compatible with the real world are key, and critical technology for that is AR (Augmented Reality). In this study, we examined research trends about AR, and will propose the directions for future AR research. We conducted LDA based topic modeling on 11,049 abstracts of published domestic and foreign AR related papers from 2009 to Mar 2022, and then looked into AR that was comprehensive research trends, comparison of domestic and foreign research trends, and research trends before and after the popularity of metaverse concepts. As a result, the topics of AR related research were deduced from 11 topics such as device, network communication, surgery, digital twin, education, serious game, camera/vision, color application, therapy, location accuracy, and interface design. After popularity of metaverse, 6 topics were deduced such as camera/vision, training, digital twin, surgical/surgical, interaction performance, and network communication. We will expect, through this study, to encourage active research on metaverse AR with convergent characteristics in multidisciplinary fields and contribute to giving useful implications to practitioners.