• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2004년도 ICEIC The International Conference on Electronics Informations and Communications
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• pp.233-236
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• 2004

This paper proposes new method for the enhancement of nonexistent high frequency spectral contents from low sample rate audio signal. For example, Due to the protocol constraint, the audio bandwidth of MP3 is restricted to 16Khz. Although band-restricted MP3 audio provide savings of storage space and network bandwidth, it suffers a major problem of a loss in high frequency fidelity such as localization, ambient information, and bright nature of audio. This paper provides a new mathematical analysis for the adaptive estimation of the high frequency contents based on the nature of the input low sample rate audio. Proposed method can be worked globally to any kind of audio such as speech and music that are restricted by sampling rate and bandwidth.

• 대한화장품학회지
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• 제33권3호
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• pp.165-173
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• 2007

선구 연구로부터 저자들은 제주 자생 식물 추출물의 항산화 및 세포보호 효과에 대한 결과의 일부를 이미 보고하였으며, 본 연구에서는 제주도에서 자생하는 나머지 37종의 식물 추출물에 대한 항산화, 미백 그리고 주름생성억제 효과를 측정하였다. 항산화 효과는 1,1-diphenyl-2-picrylhydrazyl radical(DPPH)을 이용한 free radical 소거 활성 측정, $Fe^{3+}-EDTA/H_2O_2$ 계에서 생성된 활성산소종으로 인한 luminol의 화학발광을 이용한 소거 활성, 사람 적혈구를 대상으로 하여 rose-bengal로 증감된 활성산소에 대한 세포보호 효과를 측정하였다. 미백 및 주름억제 효과측정으로는 각각 tyrosinase, elastase의 활성 저해 효과를 측정하였다. 실험결과, free radical의 소거 활성($FSC_{50}$)은 소귀나무 수피(Myrica rubra, 5 ${\mu}g/mL$), 광대싸리 수피(Securinega suffruticosa, 8 ${\mu}g/mL$)에서 높게 나타났고, 활성산소 소거 활성($OSC_{50}$)은 상수리나무 잎(Quercus acutissima)과 광대싸리 수피(Securinega suffruticosa)에서 0.009 ${\mu}g/mL$로 높게 나타났으며, 세포보호 효과(${\tau}_{50}$)는 50 ${\mu}g/mL$에서 광대싸리 수피(Securinega suffruticosa, 895 min), 버드나무 줄기(Salix koreensis, 640 min)에서 크게 나타났다. 200 ${\mu}g/mL$에서 tyrosinase의 활성 저해 효과($IC_{50}$)는 소귀나무 수피(Myrica rubra, 77.8%), elastase의 활성 저해 효과($IC_{50}$)는 버드나무 줄기(Salix koreensis, 76.2%)에서 큰 효과가 나타났다. 결론적으로 광대싸리 수피, 소귀나무 수피, 상수리나무 잎, 버드나무 줄기, 동백나무 잎/줄기 추출물은 기능성 화장품 제조를 위한 원료로 사용하기에 충분한 가능성이 있음을 확인할 수 있었으며, 향후에 제품화를 위하여 좀 더 다양한 연구들이 필요하다고 사료된다.

• 식물분류학회지
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• 제40권4호
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• pp.193-201
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• 2010

The Ryukyus Archipelago consists of about 200 nearly subtropical islands located between Japan proper and Taiwan. Previous studies have found the Ryukyus to be a region of high biodiversity with many endangered vascular plant taxa, but they are not comprehensive. Here, we discuss the phytogeographic features and circumstances of the endangered plant taxa, make suggestions for effective in situ conservation, and highlight endangered plants in the Ryukyus that require further study.

• ETRI Journal
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• 제43권6호
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• pp.1058-1080
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• 2021

Crime is not a completely random event but rather shows a pattern in space and time. Capturing the dynamic nature of crime patterns is a challenging task. Crime prediction models that rely only on neighborhood influence and demographic features might not be able to capture the dynamics of crime patterns, as demographic data collection does not occur frequently and is static. This work proposes a novel approach for crime count and hotspot prediction to capture the dynamic nature of crime patterns using taxi data along with historical crime and demographic data. The proposed approach predicts crime events in spatial units and classifies each of them into a hotspot category based on the number of crime events. Four models are proposed, which consider different covariates to select a set of independent variables. The experimental results show that the proposed combined subset model (CSM), in which static and dynamic aspects of crime are combined by employing the taxi dataset, is more accurate than the other models presented in this study.

• 한국과학교육학회지
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• 제18권3호
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• pp.297-301
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• 1998

학생들이 무엇을 탐구로 생각하는지 알아보기 위하여 학생들이 여름 방학 과제로 제출한 자유 탐구보고서의 제목을 분석하였고 제목 속에 종속 변인과 독립 변인이 포함되어 있느냐 하는 것과 변인들의 성질(범주형, 연속형)을 준거로 탐구 보고서 제목을 9가지 유형을 나눌 수 있었다. 연구 대상은 서울 소재 중학교 1학년 4개 학급 141명으로 남녀 혼성이다. 이러한 유형들의 빈도를 조사한 결과 대부분의 학생들이 보고서 제목에 변인을 명확하게 기술하지 않으며, 변인을 기술한 학생들도 주로 범주형의 변인만을 기술함을 알 수 있었다.

• 한국약용작물학회:학술대회논문집
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• 한국약용작물학회 2008년도 춘계학술발표회
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• pp.316-317
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• 2008

• 한국약용작물학회:학술대회논문집
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• 한국약용작물학회 2008년도 춘계학술발표회
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• pp.196-197
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• 2008

• BMB Reports
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• 제45권2호
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• pp.71-78
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• 2012

Bdellovibrio bacteriovorus is a predatory bacterium which attacks and consumes other bacterial strains, including the well known pathogens E. coli O157 : H7, Salmonella typhimurium and Helicobacter pylori. This remarkable activity has been the focus of research for nearly five decades, with exciting practical applications to medical, agriculture and farming practices recently being published. This article reviews many of the exciting steps research into this bacterium, and similar bacteria, has taken, focusing primarily on their use as both an antibiotic to remove harmful and pathogenic bacteria and as a probiotic to help curb and control the bacterial populations within the intestinal tract. Owing to the unique and dual nature of this bacterium, this review proposes the use of "amphibiotic" to describe these bacteria and their activities.

• Fibers and Polymers
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• 제4권1호
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• pp.8-14
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• 2003

This paper considers the potential impact of biological approaches such as bio-copying (biomimetics) and biomanipulating (e.g. genetic engineering) on future developments in the field of textiles and, in particular, fibres. If analytical tools for studying biological systems combined with those of materials science are further developed, and higher efficiency and reproducibility of genetic engineering technology can be achieved, the potential for the copying and manipulation of nature for textile innovations will be immense. The present state for both fields is described with examples such as touch and close fastener, structurally coloured fibres, the Lotus of lect (for bio-copying), as well as herbicide tolerant cotton, insecticide resistant cotton (Bt cotton), cotton polyester bicomponent fibres, genetically engineered silkworm and silk protein, and spider fibres. (for genetic engineering).

• Steel and Composite Structures
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• 제47권4호
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• pp.513-521
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• 2023

The goal of this work is to create a new and improved GWO (Grey Wolf Optimizer), the so-called Robot GWO (RGWO), for dynamic and static target tracking involving multiple robots in unknown environmental conditions. From applying ourselves with the Gray Wolf Optimization Algorithm (GWO) and how it works, as the name suggests, it is a nature-inspired metaheuristic based on the behavior of wolf packs. Like other nature-inspired metaheuristics such as genetic algorithms and firefly algorithms, we explore the search space to find the optimal solution. The results also show that the improved optimal control method can provide superior power characteristics even when operating conditions and design parameters are changed.