• 전력전자학회논문지
• /
• 제10권3호
• /
• pp.264-273
• /
• 2005

별도의 통신선 없이도 고속 통신채널을 구현할 수 있는 고속 전력선 통신 분야는 활용측면에서 유용성이 매우 높아 기술개발과 발전이 급격히 이루어지고 있다. 그러나 전력선 통신의 특성상 채널의 범용적인 모델의 구성과 해석이 불가능하여 이론적인 성능특성을 파악하기가 힘들다. 따라서 개발된 기술의 평가 및 성능 분석에 있어 정확한 기준이 모호하다. 본 논문에서는 전력선 통신 기술의 특성과 성능을 분석하기 위하여, 실 단독주택 수용가에 인터넷 접속 환경을 구축하고 다양한 시험을 수행하였다. 개발된 전력선 통신 모뎀과 통신망의 구성을 소개하고 성능측정을 수행한 결과를 토대로 현 단계에서의 기술을 분석하고, 전력선 통신망에 대한 운영상의 적정 노드 및 가입자망 전송 섹터범위 등의 사항에 대하여 기술하였다.

• Journal of Astronomy and Space Sciences
• /
• 제30권4호
• /
• pp.279-290
• /
• 2013

Due to the continuous space development by mankind, the number of space objects including space debris in orbits around the Earth has increased, and accordingly, difficulties of space development and activities are expected in the near future. In this study, among the stages for space debris removal, the implementation of a vision-based approach technique for approaching space debris from a far-range rendezvous state to a proximity state, and the ground test performance results were described. For the vision-based object tracking, the CAM-shift algorithm with high speed and strong performance, and the Kalman filter were combined and utilized. For measuring the distance to a tracking object, a stereo camera was used. For the construction of a low-cost space environment simulation test bed, a sun simulator was used, and in the case of the platform for approaching, a two-dimensional mobile robot was used. The tracking status was examined while changing the position of the sun simulator, and the results indicated that the CAM-shift showed a tracking rate of about 87% and the relative distance could be measured down to 0.9 m. In addition, considerations for future space environment simulation tests were proposed.

• 한국입자에어로졸학회지
• /
• 제18권3호
• /
• pp.61-68
• /
• 2022

In this study, a fluidized bed particle generator was developed to generate an aerosol without supply of compressed air and to increase portability. It was assumed that the mixing ratio of the test particles and beads, the input amount, and the air flow rate supplied to the generator would have effect on the aerosol generation characteristics. The product of these three parameters was set as a characteristic parameter and particle generation characteristics according to the change of the characteristic parameter were observed. As a result, it was confirmed that the input amount of test particles and beads was not suitable as a characteristic parameter and a characteristic parameter expressed as a product of the mass mixing ratio and the air flowrate was newly defined. When the new characteristic parameter is applied, it can be confirmed that the total amount of particles generated from the particle generator is a function of the characteristic parameter. As a result of measuring the amount of particle generation by adjusting the characteristic parameter, it was confirmed that the performance required for the test particle generator for the field inspection equipment of PM-2.5 sensors could be satisfied.

• Journal of Microbiology and Biotechnology
• /
• 제19권4호
• /
• pp.416-423
• /
• 2009

Hepatitis B core antigen(HBcAg) is an important serological marker used in the diagnosis of hepatitis B virus(HBV) infections. In the current study, a fast and efficient preparative purification protocol for truncated HBcAg from Escherichia coli disruptate was developed. The recombinant HBcAg was first captured by anion exchange expanded bed adsorption chromatography integrated with a cell disruption process. This online capture process has shortened the process time and eliminated the "hold-up" period that may be detrimental to the quality of target protein. The eluted product from the expanded bed adsorption chromatography was subsequently purified using size-exclusion chromatography. The results showed that this novel purification protocol achieved a recovery yield of 45.1% with a product purity of 88.2%, which corresponds to a purification factor of 4.5. The recovered HBcAg is still biologically active as shown by ELISA test.

• Biotechnology and Bioprocess Engineering:BBE
• /
• 제11권3호
• /
• pp.268-272
• /
• 2006

A dense, pellicular UpFront adsorbent ($p=1.5 g/cm^3$, UpFront Chromatography, Cophenhagen, Denmark) was characterized in terms of hydrodynamic properties and protein adsorption performance in expanded bed chromatography. Cibacron Blue 3GA was immobilised into the adsorbent and protein adsorption of bovine serum albumin (BSA) was selected to test the setup. The Bodenstein number and axial dispersion coefficient estimated for this dense pellicular adsorbent was 54 and $1.63{\times}10^{-5}m^2/s$, respectively, indicating a stable expanded bed. It could be shown that the BSA protein was captured by the adsorbent in the presence of 30% (w/v) of whole-yeast cells with an estimated dynamic binding capacity $(C/C_o = 0.01)$ of approximately 6.5 mg/mL adsorbent.

• 한국세라믹학회지
• /
• 제54권5호
• /
• pp.380-387
• /
• 2017

In this study, unstable CaO was converted into a stable Ca compound by using carbonation in a circulating fluidized bed boiler of fly ash to confirm material usability as cement admixture; also undertaken was carbonation test and mortar to examine chemical and physical change by measuring absorption rate and compressive strength. To investigate the chemical properties of circulating fluidized bed boiler fly ash, XRD and TG-DTA were used to determine how the properties of the reaction product change quantitatively during carbonation. In order to stabilize CaO, carbonation of CaO is considered to be the most desirable process. This is because $CaCO_3$, which is a Ca compound, was produced by carbonate reaction of unstable CaO, and decrease of the absorption rate and improvement of the compressive strength were observed when the carbonated fly ash was replaced with cement.

• 간호행정학회지
• /
• 제17권3호
• /
• pp.327-335
• /
• 2011

Purpose: The objective of this study was to analyze the effects of medical staffing level as bed-to-medical staff ratio on patient outcomes as length of stay (LOS) among hospitals in Korea. Methods: Two hundred and fifty one hospitals participated in the study between January and March 2008. Data for the study was requested by an electronic data interchange from the Health Insurance Review Agency in 2008. In data analysis, SPSS WIN 15.0 program was utilized for descriptive statistics, t-test, ANOVA, Pearson correlation coefficients, and multiple regression. Results: The mean score for length of stay was 13.6 days. The mean of operating bed-to-nurse ratio was 7.93:1. The predicting factors for LOS were bed-to-nurse's aide ratio, bed-to doctor's ratio, severely ill patient rate, and hospital type. These factors explained 28.9% of the variance in patient outcomes. Conclusion: This study results indicate that the relationship between medical staffing level and patient outcomes is important in the improvement of the quality of patient care. Thus, improvements in the quality of the nurse practice environment could improve patient outcomes for hospitalized patients.

• 한국신재생에너지학회:학술대회논문집
• /
• 한국신재생에너지학회 2006년도 춘계학술대회
• /
• pp.527-530
• /
• 2006

Because price of fossil fuel rises, necessity about alternative energy was risen. Studied co-combustion of RPF to coal fluid bed boiler by necessity of these althernative energy. Purpose of this study to coal fluid bed bioler RPF when did co-combustion, change operating condition and characteristic of air pollutant examine according to change of fuel characteristic, operating condition examined about combustion chamber temperature, oxygen content etc. and air pollutant examined about material that is included to allowable exhaust standard and dioxin. Co-combustion condition was 5%. It was no peculiar under test result operating condition. Concentration of Co and HCl rose according as do RPF co-combustion and the other pollutants had hardly changed. Dioxin is low concentration level more than $0.1ng-TEQ/Sm^3$. There was no pollutant that exceed akllowable exhaust standard for boiler but $SO_x,\;NO_x$ were exceeded about allowable exhaust standard for incinerating facility.

• 한국수소및신에너지학회논문집
• /
• 제30권5호
• /
• pp.436-447
• /
• 2019

The circulating fluidized bed boiler has an advantage that can burn a variety of fuels from low-grade fuel to coal. In this study, for the design of a circulating fluidized bed boiler using wood pellets, a circulating fluidized bed combustion test device using no external heater was manufactured and used. According to the increase of co-combustion rate with wood pellet, combustion fraction and heat flux by combustor height were measured and pollutant emission characteristics were analyzed. In terms of combustibility, the effect on primary and secondary air ratio were also studied. In addition, as a result of analysis of the effect of corrosive nanoparticles on the combustion of coal with wood pellets, it was confirmed that coal is mostly composed of Ca and S, whereas wood pellets are mostly composed of K, Cl, and Na.

• 로봇학회논문지
• /
• 제3권4호
• /
• pp.300-307
• /
• 2008

This paper is concerned with face recognition for human-robot interaction (HRI) in robot environments. For this purpose, we use Tensor Subspace Analysis (TSA) to recognize the user's face through robot camera when robot performs various services in home environments. Thus, the spatial correlation between the pixels in an image can be naturally characterized by TSA. Here we utilizes face database collected in u-robot test bed environments in ETRI. The presented method can be used as a core technique in conjunction with HRI that can naturally interact between human and robots in home robot applications. The experimental results on face database revealed that the presented method showed a good performance in comparison with the well-known methods such as Principal Component Analysis (PCA) and Linear Discriminant Analysis (LDA) in distant-varying environments.