• Journal of the Institute of Electronics Engineers of Korea TC
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• v.39 no.9
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• pp.28-34
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• 2002

In this paper, a new type predistorter using a low frequency intermodulation signals terms of harmonic generator is proposed. A vector modulator, in which fundamental signal is modulated with low frequency intermodulation signals derived from harmonic generator, generates predistorted third and fifth IM components. Using predistorted signals, intermodulation distortion signals of power amplifier suppressed. The suggested predistorter has been manufactured to operate in Korean PCS base-station transmitting band (1840~1870MHz). The test results show that the third IMD signal level is reduced more than 20dB and the fifth IMD signal is reduced about 10dB for CW two-tone signals. The predistorter improves the Adjacent Channel Power Ratio (ACPR) more than 10dB for CDMA (IS-95) signals.

• Electronics and Telecommunications Trends
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• v.29 no.5
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• pp.114-124
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• 2014

전자상거래의 발전과 개인 중심 사회로 변화함에 따라, 매년 통상우편에 대한 접수 물량은 지속적 감소되고 있고, 비정형 우편물과 소포(택배) 접수 물량이 증가하고 있는 추세이다. 이와 같이 우편서비스 환경변화에 적극적으로 대응하기 위해 각국의 우편물류 사업자들은 우편물 접수 및 배달업무에 정보통신기술과 자동화기술을 활용하여 고객편익 증진과 우편사업의 경영개선을 목적으로 우편용 접수 및 배달 자동화기기 기술을 개발 및 도입하여 운영하고 있다. 본고에서는 우편용 접수 자동화기기와 무인 택배시스템에 대한 국외 기술동향과 최근 무인우체국 구축에 사용된 국내 우편 접수 및 배달 자동화기기 기술개발 현황을 살펴보고 추후 발전방향을 제시하고자 한다.

• Journal of Integrative Natural Science
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• v.1 no.3
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• pp.221-229
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• 2008

본 논문에서는 기존의 개인 식별 방법의 한계를 해결하는 대안으로 떠오르고 있는 생체인식 기술 중 인식률이 뛰어나고 신뢰성 있는 홍채인식 시스템을 구현하고자 한다. 구현을 위하여 신호처리 분야에서 주로 사용되는 wavelet변환으로 계수 특징 값 추출을 하였으며, 인식률을 알아보기 위하여 신경망 기법을 이용하고자 한다. 그러나 신경망 기법에서 주로 사용되는 비선형 최적화기법인 Scale Conjugate Gradient는 최적화 문제점을 해결하기에는 수렴속도가 느리기 때문에 적합하지 않다. 따라서 본 논문에서는 기존 Scale Conjugate Gradient를 보완한 Levenberg-Marquardt Back-Propagation을 홍채인식에 적용하여 구현함으로써 인식율을 높이고자 한다. 적용한 알고리즘 구현으로 해의 수렴정도, 변수 벡터의 변화정도에 따라 크기를 적절히 변화시킴으로써 수렴속도를 개선하고, 효율성과 안정성을 동시에 얻을 수 있었다.

• The Journal of the Acoustical Society of Korea
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• v.17 no.4
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• pp.28-34
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• 1998

미래 개인 휴대통신에서는 고속의 데이터 서비스를 위하여 높은 대역폭 효율을 요 구하게 된다. 무선통신 서비스를 향상시키기 위하여 코딩기법, 변조기법, 다중화기법 등의 다양한 방법이 연구되고 있다. 이중에서 특히 변조기법은 시스템의 성능을 결정하는 중요한 요소가 된다. 본 논문에서는 PSK. OQPSK, π/4 DQPSK, MSK, GMSK의 다섯가지 변조기 법에대한 BER성능을 시뮬레이션하였다. 시뮬레이션을 위한 다중경로 페이딩채널로서 3가지 서로 다른 채널을 적용하였다. 이때 시뮬레이션을 위하여 1.544Mbps의 전송속도와 1.9GHz 의 반성주파수 환경을 고려하였다. 또한 fractional 선형 등화기를 적용하여 변조방식에 따른 성능향상 정도를 비교하였다. 채널 Ⅰ, Ⅱ, Ⅲ에 대해 각각 30dB, 20dB, 10dB 정도에서 error floor현상이 발생했으며 π/4 DQPSKS가 가장 낮은 BER 특성을 보인 반면 QPSK는 가장 높은 BER을 나타냈다. 등화기를 적용했을 때는 GMSK의 성능향상이 가장 크게 나타 났다.

• Korean Journal of Social Welfare
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• v.69 no.4
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• pp.41-65
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• 2017

This study aimed to examine the social transition, which is often metaphorized as the Fourth Industrial Revolution, within the context of social work practice and to explore measures to improve social work practice in such transition. Four social welfare researchers held seven discussions to predict the social changes in the near future centered on the Fourth Industrial Revolution and find the corresponding development strategies in social work practice; collective autobiography method was used to analyze the discussion. The analysis ascertained hyper connectivity, the advent and expansion of new communities, diversification and individualization, and the emergence of new criteria for the assessment of one's quality of life as the distinctive qualities of the near future. It was analyzed that humans and organic materials will be interconnected through spatial and temporal transcendence and that humans liberated from labor will seek for diverse communities while the number of atomized individual will increase simultaneously. Furthermore, the rise of new order of life accompanied by both the expansion of diversification and individualization and the ecological worldview brought forth by post materialistic trend was predicted. Meanwhile, the disengagement from macroscopic context, a biased inclination towards technique orientated professionalism, and individualistic social work practices without integrity were identified as the limitations of the current social work practice. This study presented three goals for social work practice to help it overcome its current shortcomings and correspond to the social changes: first, the rearrangement of practice knowledge, technique, and value so that it is based on humans and society, which are the essence of social practice work; second, the practice, such as sharing economy, that expands the individuals' boundaries of life to the community; three, the restoration of the desirability of professional social works by examining its special nature.

• The Korean Journal of Applied Statistics
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• v.32 no.1
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• pp.129-138
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• 2019

Ammunition is an integral element of a weapon systems and in calculating fighting strength. The Korea Army utilizes the basic load (B/L) concept to supply ammunition smoothly. The required supply rate (RSR) is the basis of a B/L that is estimated from real combat data that includes a troop's mission and operation terrain. The current RSR is based on Korean War data and the sample mean has some problems in applications to modern combat. Therefore, this study used Korea Combat Training Center (KCTC) data that is similar to real combat to estimate rifle ammunition RSR. We used a quantile of truncated Weibull distribution to estimate rifle ammunition RSR considering that rifle ammunition consumption data in KCTC is truncated. As a result, we obtained a rifle ammunition RSR which covers most ammunition consumption by reflecting the individual consumption of rifle ammunition.

• The Journal of the Acoustical Society of Korea
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• v.15 no.6
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• pp.41-46
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• 1996

Conversations over telephone line are easily monitored and therefore acceptable level of security is not provided. In this paper, we propose the design of scrambler for secure communication and real time implementation of it. Especially, we con reduce the complexity of hardware and implement it easily by designing the scrambling system which doesn't require synchronization signal, and provide the scrambling filter with a sufficient level of security of adding new gain into the scrambling system.

• Journal of Digital Convergence
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• v.13 no.1
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• pp.463-468
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• 2015

A study on how a launcher as smart phone application was utilized as brand communication by deriving a characteristic element that could be changed into an extended function which carried out brand communication function going beyond the basic function of launcher pre-installed for the purpose of UI differentiation according to each device brand. In the results of analyzing the items and features of brand communication shown in each detailed item after classifying properties of launcher components into that of home component and personalization function element, (1) brand image identity element and (2) service marketing commitment element was derived.

• Journal of Korea Game Society
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• v.19 no.2
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• pp.95-110
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• 2019

This paper aims to study on attribute of interaction between user from cultural capital perspective of Bourdieu who expanded the concept of capital and presented class production and reproduction through 'World of Warcraft' play and analysis. The results of this study is that First, game ability showed properties of cultural capital that embodied, objectified, institutionalized. Second, the types of interaction by difference of cultural capital appeared that lurking, reciprocity, exclusion. This study identified game ability have attributes of cultural capital and that Due to the nature of the interaction for 'Disticion', individual actions are related to the process of accumulating power and contribute to class reproduction.

• Korean Journal of Environment and Ecology
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• v.16 no.1
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• pp.55-67
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• 2002

Lately a few of new ecological management policies have been developed and implemented to need objectives of national parks in effective ways. Examples include trail closing for preserving bears, no pets allowance for possible diesease expansion, and no fire in national parks. Such new policies can cause visitors and local residents inconvenience and dissatisfaction. Decision-making processes based on public participation became more important as a primary mean to decrease such undesirable reactions. This study examined conflicts between collective value and individual preference in process building an ecological management policy by analysis of questionnaire survey results. The subjects of the present study were 242 university students. The majority(93.%) accepted the need of public participation in decision-making processes, and the most important reason was that such processes can properly help decison makers understand what the public and local residents want(51.7%). They also answered that individual property right can be limited for preserving species but the limited right should be compensated by the government(93.0%). The great majority(97.1%) of respondents supported the trail closing policy designed to protect bears(Urus thibetanus) from being captured no matter what their personal preference is. On the contrary, more than half of the respondents answered that local residents should be allowed to gather herbs and plants even within national park area since they have been doing for a long time. The results of the present study seem to support major findings of some previous studies that it is critical for policy makers to encourage the public to consider issues under debate from the perspective of collective value rather than individual preference and provide them with necessary information and chances to discuss to each other in public participation processes.