• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제8권8호
• /
• pp.2663-2674
• /
• 2014

For cognitive radio sensor networks (CRSNs) that use underlay-based spectrum access, the location of the primary user (PU) plays an important role in the power control of the secondary users (SUs), because the SUs must keep the minimum interference level required by the PU. Received signal strength (RSS)-based localization schemes provide low-cost implementation and low complexity, thus it is suitable for the PU localization in CRSNs. However, the RSS-based localization schemes have a high localization error because they use an inexact path loss exponent (PLE). Thus, applying a RSS-based localization scheme into the PU localization would cause a high interference to the PU. In order to reduce the localization error and improve the channel reuse rate, we propose a RSS-based PU localization scheme that uses distance calibration for CRSNs using underlay model-based spectrum access. Through the simulation results, it is shown that the proposed scheme can provide less localization error as well as more spectrum utilization than the RSS-based PU localization using the mean and the maximum likelihood calibration.

• Applied Science and Convergence Technology
• /
• 제24권4호
• /
• pp.111-116
• /
• 2015

The graphene oxide (GO) and graphene oxide quantum dots (GOQDs), which have gained research interest as new types of light-emitting materials, were synthesized by the modified Hummers method for oxidation of graphite flake and graphite nanoparticle. The optical properties of GO and GOQDs have been compared by mean of photoluminescence (PL), PL excitation (PLE), UV-vis absorbance, and time-resolved PL. The GO have an absorption peak at 229 nm and shoulder part at 310 nm, whereas the GOQDs show broad absorption with a gradual change up without any absorption peaks. The PL emission of GOQDs and GO showed the green color at 520 nm and the red color at 690 nm, respectively. The red emission of GO showed faster PL decay time than the green emission of GOQDs. In particular, the temporal PL profile of the GO showed redshift from 560 nm to 660 nm after the pump event.

• 한국생물공학회:학술대회논문집
• /
• 한국생물공학회 2001년도 추계학술발표대회
• /
• pp.662-665
• /
• 2001

PLE를 이용한 levofloxacin의 생산에서 기질 150 mM 사용의 경우 두배의 몰농도 로 ${\alpha}-CD$를 사용하여 산물의 생산량을 3.7 배까지 증가시킬 수 있었다. 그러나 이 경우 ${\alpha}-CD$의 사용량이 많아 경제성이 떨어지는 단점이 있다. 이에 같은 몰농도로 ${\alpha}-CD$를 사용하고 pH에 변화를 주어 용해도를 향상시켜 보았다. 기질 100 mM의 경우 pH 5.6에서 같은 몰농도의 ${\alpha}-CD$를 사용한 경우 ${\alpha}-CD$를 사용하지 않은 것에 비해 4.4배의 수율의 증대가 있었다.

• 한국정보시스템학회지:정보시스템연구
• /
• 제28권4호
• /
• pp.403-424
• /
• 2019

Purpose The objective of this study is to determine the programming language for improving algorithmic thinking of basic software education for non-majors, which has recently been receiving attention to nurture talents needed in the era of the Fourth Industrial Revolution. Design/methodology/approach In this study, Delphi method was used to select the suitable programming language for the features of each of five departments for basic software education for non-majors in order to develop the capability of algorithmic thinking. The survey was conducted three times to 21 experts, and the results were analyzed using quantitative analysis (CVR) values and stability. Findings For the most suitable programming language for each department determined in this study, App Inventor was selected for humanities department, RUR-PLE for natural science department, App Inventor for social science department, Python for engineering department, and Scratch for fine arts department. This is expected to be used as the basis for determining the direction of curriculum and operation of universities starting basic software education through programming language by department proposed in this study.

• 한국의상디자인학회지
• /
• 제13권3호
• /
• pp.165-175
• /
• 2011

In this study, document research on Jogakbo and Tosi were carried out and textile designs were developed by applying Jogakbo and Tosi together for motives. The purposes of this study were to develop a unique textile design, and then to enhance the competitiveness of Korean textile industry in the world market and pass down a Korean traditional fiber art cultural legacy. The results are as follows; First, the title of textile design was decided to "innocence of childhood" and the concepts are "sim ple heart ed, pure heart, sweet", in order to develop textile design for the young generation Second, Motives were chosen Jogakbo and Tosi to reflect Korean traditionality and identity and textile designs were expressed on ground fashion trends for modernity. Third, developed textile designs were printed with digital printing method for eco-friendly and productivity, and various articles clothing, nectie, shoes, bag, bedings were producted with developed fabrics for multipurpose. Forth, the developed textile designs were evaluated highly in point of Korean traditionality and identity, felling of simplehearted, pure hear and sweet, modernity and fashion trend, and preference by a sensory test of developed test design.

• 대한기계학회논문집
• /
• 제19권3호
• /
• pp.846-857
• /
• 1995

An experimental study is made of turbulent shear flows in a nearly two-dimensional 90.deg. curved duct by using the hot-wire anemometer. The Reynolds normal and shear stresses, triple velocity products, integral length scales, Taylor micro length scales and dissipation length scales are measured and analyzed. For a positive shear at the inlet, the afore-mentioned turbulence quantities are all suppressed. However, when the inlet shear flow is negative, they are augmented, i.e., the convex curvature suppresses the turbulence whereas the concave curvature augments it. It is found that the curvature effects are rather sensitive to the triple velocity products than the Reynolds stresses. The evolution of turbulence under the curvature with the different shear conditions is well described by the modified curvature parameter S' and the non-dimensional development time ${\tau}$.'

• 한국정보과학회논문지:컴퓨팅의 실제 및 레터
• /
• 제13권1호
• /
• pp.46-58
• /
• 2007

최근 많은 소프트웨어 개발 프로젝트들은 지속적으로 요구사항들이 변경되는 대규모의 복잡한 시스템이며 컴포넌트 기반이나 제품계열 소프트웨어 개발 방식과 같이 아키텍처 기반으로 소프트웨어를 개발하고 있다. 이러한 소프트웨어 개발환경에서 생산성이나 유지보수 향상을 위해서는 무엇보다도 유연하고 확장 가능한 아키텍처가 필요하다. 본 논문에서는 CBD(Component Base Development) 기반의 비즈니스 어플리케이션 개발 및 유지보수 시 생산성과 유지보수 향상을 위해 필요한 유연성과 확장성 품질속성을 가진 소프트웨어 아키텍처를 제시하고 이들 품질속성을 달성하기 위한 방법들을 아키텍처 모델을 통해 설명한다. 또한, 본 논문에서는 최근 프리젠테이션(Presentation) 프레임워크(Framework)로 잘 알려진 Struts와 JBean이라 불리는 본 논문에서 제안한 프레임워크의 성능을 비교했다. JBean 프레임워크는 프리젠테이션 프레임워크와 비즈니스 로직 프레임워크를 가지고 있기 때문에 공정한 실험을 위해 JBean에서 비즈니스 로직 프레임워크에 관련된 모듈을 제거하고 단지 프리젠테이션단 프레임워크만 가지고 실험을 한 결과 JBean의 프리젠테이션 단 프레임워크가 평균 초당 18개의 거래를 더 처리하고 있다.

• 한국대기환경학회지
• /
• 제34권1호
• /
• pp.120-143
• /
• 2018

The analytical methods and their ambient levels of organic nitrogenous compounds such as nitrosamines, nitramines (nitroamines), imines, amides and nitro-polycyclic aromatic hydrocarbons (nitro-PAHs) in the atmosphere are summarized and discussed. Sampling for the analysis of organic nitrogenous compounds was mostly conducted using high volume air sampler. The direct liquid extraction (DLE) using sonification and the pressurized liquid extraction (PLE) using the accelerated solvent extraction (ASE) have been frequently employed for the extraction of organic nitrogenous compounds in the atmospheric samples. After extraction, clean-up via filtration and the solid phase extraction (SPE) and concentrations using nitrogen and rotary evaporator have been generally conducted but in some studies the clean-up and concentration steps have been omitted to prevent the loss of analyte and improve the recovery rate of the analytical procedure. Instrumental analysis was mainly carried out using gas chromatography (GC) or the high performance liquid chromatography (HPLC) coupled with the single quadrupole mass spectrometer or tandem mass spectrometer in the electron ionization (EI), positive chemical ionization (PCI) and negative chemical ionization (NCI) mode and analysis sensitivity of nitrosamines and nitramines were higher in NCI mode. Desirable sampling and analysis methods for analyzing particulate organic nitrogenous compounds are suggested.

• 한국화재소방학회논문지
• /
• 제13권1호
• /
• pp.21-30
• /
• 1999

본 연구는 세 가지 유형의 아트리움 공간에 대해서 Zone 모델과 Field 모델을 비교하였으며, Zone 모델로는 FIRST, CFAST, NIST에서 개발된 CCFM.VENTS 그리고 CSIRO에서 개발된 NBTC 1-room 모델을 사용하였고 Field 모델로는 Chow에 의해 개발된 화재모델과 본 연구에서 개발된 SMEP을 사용하였다. 두 모델들에 대한 비교는 서로 유사한 결과를 보였으며, 특히 PISO 알고리즘을 사용한 SMEP의 경우가 SIMPLER 알고리즘이 적용된 field 모델에 비해 더 빠른 계산시간을 보여 주었다.

• 한국광학회:학술대회논문집
• /
• 한국광학회 2008년도 동계학술발표회 논문집
• /
• pp.403-405
• /
• 2008

Solid state lighting 용 적색 형광체로 적용하기 위하여 $BaTiO_3$:$Pr^{3+}$:$Ga^{3+}$를 다음과 같이 합성하였다. 출발 물질로 $BaCO_3$,$Pr(NO_3)_3$ $6H_2O$, $TiO_2$, $Ga_2O_3$을 사용 하였으며, $BaTiO_3$:$Pr^{3+}\;_x$(x=$0.001{\sim}0.2$):$Ga^{3+}\;_y$(y=0.05, 0.1, 0.5 1, 2, 3)를 각각의 조성대로 혼합한 후 $600^{\circ}C$에서 10시간 전처리 하였다. 전처리한 시료를 시편으로 제조하여 $1200^{\circ}C$ 공기중에 4시간 소성하여 최종물질인 $BaTiO_3$:$Pr^{3+}\;_x$:$Ga^{3+}\;_y$을 얻었다. 이 화합물을 X-선 회절 분석 결과 공간군 P4MM을 갖는 페로브스카이트임을 알 수 있었다. 이 화합물을 적색형광체로 적용하기 위해 PL과 PLE측정을 통하여 형광특성을 알아본 결과 618nm에서 x=0.011, y=1.0 일 때 특성이 가장 우수한 것으로 나타났다.