• 한국문헌정보학회지
• /
• 제52권1호
• /
• pp.447-467
• /
• 2018

인물에 대한 기록정보는 사회의 주요 분야에서 특정기준에 맞는 유명한 인물에 한정하여 정보를 수집, 가공, 제공하는 인물데이터베이스 형태가 일반적이었으나 최근 위키피디아와 같이 이용자들이 참여하여 다양한 인물에 대하여 자유롭게 서술하며 디지털 아카이브로 축적하는 체제가 활성화되고 있다. 이 연구는 위키피디아 바이오그래피 포털에서 범죄자, 교수, 영화감독 카테고리에서 인물 유형별로 500건의 데이터를 각각 수집하여 서술된 내용간 유형별 차별성이 있는지 계량적으로 분석하였다. 용어의 빈도 분석과 차별지수 분석을 수행한 결과 차별지수가 각 유형별로 특화되어 있는 내용을 표현하는데 효과적인 것으로 나타났다. 이 연구에서는 차별지수값이 높은 상위 100개의 용어와 세 유형에 공통적으로 출현한 용어 고빈도어 100개를 워드 클라우드 형태로 활용하여 특정 유형의 인물에 대하여 서술하는 이용자와 이를 승인하는 에디터가 참조할 수 있는 가이드를 제시하고자 하였다.

• ETRI Journal
• /
• 제45권2호
• /
• pp.267-276
• /
• 2023

R&D strategies of companies with low and high technological levels are discussed based on the concept of technology convergence and divergence. However, empirically detecting enterprise technology convergence in the distribution of enterprise technology (total productivity increase) over time and identifying key change factors are challenging. This study used a novel statistical indicator that captures the internal technology distribution change with a single number to clearly measure the technology distribution peak as a change in critical bandwidth for enterprise technology convergence and presented it as evidence of each technology convergence or divergence. Furthermore, this study applied the quantitative technology convergence identification method. Technology convergence appeared from the separation of total corporate productivity distribution of 69 IT companies in Korea in 2019-2020 rather than in 2015-2016. Results indicated that when the total technological level was separated from the technology leading and technology catch-up, IT companies were found to be pursuing R&D strategies for technology catch-up.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제11권3호
• /
• pp.1441-1461
• /
• 2017

Nowadays, Dynamic Adaptive Streaming over HTTP (DASH) has become very popular in streaming multimedia contents. In DASH, a client estimates current network bandwidth and then determines an appropriate video quality with bitrate matching the estimated bandwidth. Thus, estimating accurately the available bandwidth is a significant premise in the quality of video streaming, especially when network traffic fluctuates substantially. To cope with this challenge, researchers have presented various filters to estimate network bandwidth adaptively. However, experiment results show that current schemes either adapt slowly to network changes or adapt fast but are very sensitive to delay jitter and produce sharply changed estimation. This paper presents a novel bandwidth estimation scheme based on Moving Average Convergence Divergence (MACD). We applied an MACD indicator and its two thresholds to classifying network states into stable state and agile state, based on the network state different filters are applied to estimate network bandwidth. In the paper, we studied the performance of various MACD indicators and the threshold values on bandwidth estimation. Then we used a DASH proxy-based environment to compare the performance of the presented scheme with current well-known schemes. The simulation results illustrate that the MACD-based bandwidth estimation scheme performs superior to existing schemes both in the speed of adaptively to network changes and in stability in bandwidth estimation.

• Bulletin of the Korean Chemical Society
• /
• 제23권1호
• /
• pp.53-58
• /
• 2002

A new PVC-membrane electrode for $Ag^+$ ion based on a thia-substituted macrocyclic diamide has been prepared. The electrode exhibited a Nernstian response for $Ag^+$ over a wide concentration range $(1.7{\times}10^{-6}-1.0{\times}10^{-1}M)$. It has a response time <15 s and can be used for at least 3 months without divergence. The proposed membrane sensor revealed good selectivities for $Ag^+$ over a variety of metal ions and can be used in a pH range 3.0-7.5. It has been used successfully for direct determination of $Ag^+$ in different real samples and, as an indicator electrode, in the titration of silver ion.

• Bulletin of the Korean Chemical Society
• /
• 제23권11호
• /
• pp.1635-1639
• /
• 2002

A new solvent polymeric membrane sensor based on tetra(p-chlorophenyl)porphyrinato manganese (III) acetate is described which demonstrates excellent selectivity toward the triiodide ion. The electrode has a linear dynamic range between 1.0 ${\times}$ $10^{-2}$ M and 7.0 ${\times}$$10^{-6}$M with a Nernstian slope of $-59.6{\pm}1$ mV per decade and a detection limit of 5.0 ${\times}$$10^{-6}$M. The proposed sensor revealed good selectivities for triiodide over a wide variety of other anions and could be used in a pH range 2-9. The electrode can be used for at least two months without any considerable divergence in potential. It was applied as indicator electrode in potentiometric titration of the triiodide and As(III) ions.

• Bulletin of the Korean Chemical Society
• /
• 제29권2호
• /
• pp.398-404
• /
• 2008

A new solvent polymeric membrane electrode, based on N,N'-bis(salicylidene)-2,2-dimethylpropane-1,3-diamine Ni(II) as the ionophore, was designed. The oxalate-selective electrode has the dynamic range between 1.0 10-6 M and 1.0 10-1 M with a Nernstian slope of -28.7 1.0 mV per decade. The detection limit was 6.3 10-7 M. The proposed electrode revealed good selectivities for oxalate over a variety of other anions and could be used in a pH range of 2.0-7.8. The electrode can be used for at least two months without any considerable divergence in potential. The designed electrode was applied as an indicator electrode in the potentiometric determination of oxalate in real samples.

• International Journal of Industrial Entomology and Biomaterials
• /
• 제46권2호
• /
• pp.41-54
• /
• 2023

The blue-tailed damselfly, Ischnura elegans Van der Linden, 1820 (Odonata: Coenagrionidae), is a climate-sensitive indicator species in South Korea. In this study, we sequenced the complete mitochondrial genome (mitogenome) of I. elegans collected from South Korea for subsequent population genetic analysis, particularly to trace population movements in response to climate change. The 15,963 base pair (bp)-long complete mitogenome of I. elegans has typical sets of genes including a major non-coding region (the A+T-rich region), and an arrangement identical to that observed in ancestral insect species. The ATP6, ND3 and ND1 genes have the TTG start codon, which, although rare, is the canonical start codon for animal mitochondrial tRNA. The A/T content was 71.4% in protein-coding genes, 72.1% in tRNAs, 72.9% in the whole genome, 74.7% in srRNA, 75.3% in lrRNA, and 83.8% in the A+T-rich region. The A+T-rich region is unusually long (1,196 bp) and contains two subunits (192 bp and 176-165 bp), each of which is tandemly triplicated and surrounded by non-repeat sequences. Comparison of the sequence divergence among available mitogenomes of I. elegans, including the one from the current study, revealed ND2 as the most variable gene, followed by COII and COI, suggesting that ND2 should be targeted first in subsequent population-level studies. Phylogenetic reconstruction based on all available mitogenome sequences of Coenagrionidae showed a strong sister relationship between I. elegans and I. senegalensis.

• Bulletin of the Korean Chemical Society
• /
• 제27권9호
• /
• pp.1418-1422
• /
• 2006

In this work the construction of a novel poly(vinyl chloride) membrane sensor based on 2,2'-dianiline disulfide (DADS) as a neutral carrier, o-nitrophenyloctyl ether (NPOE) as a plasticizer and sodium tetraphenyl borate (NaTPB) as an anionic site with unique selectivity towards Tm(III) ions is reported. The electrode has a linear dynamic range between $1.0\;{\times}\;10^{-6}$ and $1.0\;{\times}\;10^{-2}$ M, with a nice Nernstian slope of 19.5 ${\pm}$ 0.3 mV per decade and a detection limit of $4.0\;{\times}\;10^{-7}$ M at the pH range of 4.8-8.5. It has a very fast response time (<15 s) in the whole concentration range, and can be used for at least 4 weeks without any considerable divergence in the electrode potentials. The proposed sensor revealed comparatively good selectivity with respect to most common metal ions, and especially lanthanide ions. It was used as an indicator electrode in the potentiometric titration of Tm(III) ions with EDTA and in direct determination of concentration of Tm(III) ions in binary mixtures. It was also applied in determination of fluoride ions in mouth wash preparations.

• Bulletin of the Korean Chemical Society
• /
• 제26권1호
• /
• pp.51-56
• /
• 2005

A PVC membrane electrode for lead ion based on 1-phenyl-2-(2-quinolyl)-1,2-dioxo-2-(4-bromo) phenylhydrazone (PQDBP) as ionophore was demonstrated. The optimum composition of the membrane was 30 wt% poly(vinyl chloride), 60 wt% dibutyl phthalate as a plasticizer, 4 wt% ionophore and 6 wt% sodium tetraphenylborate as additive. The electrode exhibits a Nernstian response (28.7 mV decade$^{-1}$) for Pb$^{2+}$ over a wide concentration range (1.0 ${\times}$ 10$^{-1}$ to 1 ${\times}$ 10$^{-6}$ M) with a detection limit of 6.0 ${\times}$ 10$^{-7}$ M. This sensor has a short response time and can be used for at least 2 months without any divergence in potentials. The proposed electrode could be used in a pH range of 3.0-6.0 and revealed good selectivities for Pb$^{+2}$ over a wide variety of other metal ions. It was successfully applied as an indicator electrode for the potentiometric titration of lead ion with potassium chromate and for the direct determination of lead in mine.

• Bulletin of the Korean Chemical Society
• /
• 제28권1호
• /
• pp.68-72
• /
• 2007

A new PVC membrane potentiometric sensor that is highly selective to Hg2+ ions was prepared, using bis(2-hydroxybenzophenone) butane-2,3-dihydrazone (HBBD) as an excellent hexadendates neutral carrier. The sensor works satisfactorily in the concentration range of 1.0 × 10-6 to 1.0 × 10-1 mol L-1 (detection limit 4 × 10-7 mol L-1) with a Nernstian slope of 29.7 mV per decade. This electrode showed a fast response time (~8 s) and was used for at least 12 weeks without any divergence. The sensor exhibits good Hg2+ selectivity for a broad range of common alkali, alkaline earth, transition and heavy metal ions (lithium, sodium, potassium, magnesium, calcium, copper, nickel, cobalt, zinc, cadmium, lead and lanthanum). The electrode response is pH independent in the range of 1.5-4.0. Furthermore, the developed sensor was successfully used as an indicator electrode in the potentiometric titration of mercury ions with potassium iodide and the direct determination of mercury in some binary and ternary mixtures.