• Proceedings of the IEEK Conference
• /
• summer
• /
• pp.233-236
• /
• 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.

• Journal of the Society of Cosmetic Scientists of Korea
• /
• v.33 no.3
• /
• pp.165-173
• /
• 2007

In the previous study, we reported the antioxidative and cellular protective effects of Jeju native plant extracts. In this study, we investigated the anti-oxidative, anti-wrinkle and whitening effects of new 37 plant extracts collected from self-growing plants in Jeju island. Their anti-oxidant activities were measured by the 1,1-diphenyl-2-picrylhydrazyl(DPPH) radical scavenging assay and reactive oxygen species(ROS) scavenging assay in $Fe^{3+}-EDTA/H_2O_2$ system. The cytoprotective properties of 37 plant extracts were assessed in the rose-bengal sensitized photohemolysis of human erythrocytes. The inhibitory effect of 37 plant extracts on tyrosinase were investigated to assess their whitening efficacy. Finally, their anti-elastase activities were measured to predict the anti-wrinkle efficacy in the human skin. The results showed that the extracts of Myrica rubra stem bark and Securinega suffruticosa have the free radical scavenging activity($FSC_{50}:\;5,\;8{\mu}g/mL$, respectively), and the extracts of Quercus acutissima leaf and Securinega suffruticosa stem bark have the prominent ROS scavenging activity($OSC_{50}:\;0.009{\mu}g/mL$). Photohemolysis of erythrocytes in the presence of rose-bengal as a sensitizer was inhibited by the extracts of Securinega suffruticosa stem bark and Salix koreensis stem(${\tau}_{50}$, 895 min, 640 min at 50 ${\mu}g/mL$, respectively. Myrica rubra stem bark extract(77.8% at 200 ${\mu}g/mL$) and Salix koreensis stem extract(76.2% at 200 ${\mu}g/mL$) also have the inhibitory effect on tyrosinase and elastase activities, respectively. These results indicated that the stem park of Myrica rubra, Securinega suffruticosa, and Camellia japonica, the stem of Salix koreensis, and the leaf of Quercus aqutissima and Camellia japonica could have e benefitial effects when they are added as ingredients in cosmetics.

• Korean Journal of Plant Taxonomy
• /
• v.40 no.4
• /
• pp.193-201
• /
• 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
• /
• v.43 no.6
• /
• pp.1058-1080
• /
• 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.

• Journal of The Korean Association For Science Education
• /
• v.18 no.3
• /
• pp.297-301
• /
• 1998

To investigate the 7th graders' ideas on inquiry, researchers analysed the titles of inquiry report, which were submitted as summer vacation homework. The subjects were four classes of 141 thirteen year old boys and girls in a school in Seoul. After analysing the titles of student's report, researchers classified the titles into 9 types according to the clarity and the nature of variables in the titles. The fact that few students represented the variables in the report title and most of the variables used were categoric was found.

• 한국약용작물학회:학술대회논문집
• /
• 2008.05a
• /
• pp.316-317
• /
• 2008

• 한국약용작물학회:학술대회논문집
• /
• 2008.05a
• /
• pp.196-197
• /
• 2008

• BMB Reports
• /
• v.45 no.2
• /
• pp.71-78
• /
• 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
• /
• v.4 no.1
• /
• pp.8-14
• /
• 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
• /
• v.47 no.4
• /
• pp.513-521
• /
• 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.