• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.41 no.8
• /
• pp.917-920
• /
• 2016

SpSF algorithm is direction-of-arrival estimation algorithm based on sparse representation of incident signlas. Cost function to be optimized for DOA estimation is multi-dimensional nonlinear function, which is hard to handle for optimization. After some manipulation, the problem can be cast into convex optimiztion problem. Convex optimization problem tuns out to be constrained optimization problem, where the parameter in the constraint has to be determined. The solution of the convex optimization problem is dependent on the specific parameter value in the constraint. In this paper, we propose a rule-of-thumb for determining the parameter value in the constraint. Based on the fact that the noise in the array elements is complex Gaussian distributed with zero mean, the average of the Frobenius norm of the matrix in the constraint can be rigorously derived. The parameter in the constrint is set to be two times the average of the Frobenius norm of the matrix in the constraint. It is shown that the SpSF algorithm actually works with the parameter value set by the method proposed in this paper.

• Journal of the Korean Institute of Gas
• /
• v.15 no.4
• /
• pp.21-26
• /
• 2011

Type-3 cylinder liner has a limitation of machining the standard specimen for fracture toughness test because it has approximately 5 mm in thickness as well as a curvature. Hence, it needs to be employed a miniature specimen test technique to evaluate fracture toughness of the cylinder liner. In this study, small punch (SP) test method was employed to evaluate fracture toughness of the cylinder liner. Load-displacement curve result measured from the SP test showed that the liner material was failed during membrane stretching in the general SP load-displacement curve. Additionally, it was shown that liner material was isotropic although the amount of plastic deformation was different depending on the direction due to manufacturing process characteristics. Fracture toughness, $J_{Ic}$, was evaluated using the SP test data. The value of fracture toughness obtained was $13.0kJ/m^2$. This value was similar to that of the same kind of materials. Therefore, the fracture toughness evaluated using the SP test data was reasonable.

• Proceedings of the KSME Conference
• /
• 2000.11a
• /
• pp.105-110
• /
• 2000

The Micromechanics test is new test method which uses comparatively smaller specimen than that required in conventional material tests. There are several methods, such as small-specimen creep test, the continuous indentation test, and small punch(SP) test. Among them, the small punch(SP) test method has been applied to many evaluation fields, such as a ductile-brittle transition temperature, stress corrosion cracking, hydrogen embrittlement, and fracture properties of advanced materials like FGM or MMC. In this study, the small punch(SP) test is performed to evaluate the mechanical properties at high/low temperature from $-196^{\circ}C$ to $650^{\circ}C$ and the material degradation for virgin and aged materials of 9Cr1MoVNb steel which has been recently developed. The ${\Delta}P/{\Delta}{\delta}$ parameter defined a slope in plastic membrane stretching region of SP load-displacement curve decreases according to the increase of specimen temperature, and that of aged materials is higher than the virgin material in all test temperatures. And the material degradation degrees of aged materials with $630^{\circ}C$ -500hrs and $630^{\circ}C$ -1000hrs are $36^{\circ}C$ and $38^{\circ}C$ respectively. These behaviors are good consistent with the results of hardness($H_v$) and maximum displacement(${\delta}_{max}$).

• Journal of the Korea Concrete Institute
• /
• v.26 no.6
• /
• pp.671-677
• /
• 2014

In this research, flow experiments and simulation of highly flowable concrete has been attempted using a viscoplastic particle method varying with dosages of SP admixture and water-cement (W/C) ratios. Rheological and flow characteristics of flowable concrete manufactured in domestic products of cement, aggregates, and SP admixtures were investigated by experimental programs varying with mix proportions. From experiment, the predictive model of rheological characteristics of flowable concrete has been newly proposed considering with the effects of the W/C ratio and the dosage of SP admixture, and the effect of mixing proportion has also been incorporated into shear stress and strain rate curve of flowable concrete in the current method. A series of L-box flow test of highly flowable concrete varying with dosages of SP admixture and W/C ratios was compared with the proposed model.

• Journal of the Institute of Electronics Engineers of Korea SP
• /
• v.44 no.2 s.314
• /
• pp.137-143
• /
• 2007

The P-ECLMS algorithm adapted the existing Post-Processing method occurs the distortion of the near-end signal at the double-talk situation. To solve this problem, we propose the SP-ECLMS algorithm which makes the Post-Processing coefficient differently at the case of the single-talk and the double-talk. When the correlation level is not output less than 30%, the proposed algorithm output the original signal to prevent the signal's distortion.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.6 no.5
• /
• pp.797-802
• /
• 2011

RFID is recognized to technically occupy important position in ubiquitous computing environment and expected to create new markets in a variety of fields from now on. In order to generalize RFID system, it is required to solve the problem of privacy invasion and expedite lots of tags We suggest efficient RFID Tag Identification to identify tags quickly on the satisfaction with 3 security requirements of privacy protection in this paper. This methods are transferred to Grid environment through parallel analysis of Hash-Chain, and we measure performance of each nodes under the Grid environment. Then, We'll suggest SP-Division Algorithm to identify tags with each nodes and implement it in a Grid environment.

• Korean Journal of Microbiology
• /
• v.45 no.2
• /
• pp.140-147
• /
• 2009

In this study, anaerobic enrichment cultivation was performed with the sediments from the Gimpo and Inchon areas. Lactate as an electron donor and PCE as an electron acceptor was injected into the serum bottle with an anaerobic medium. After the incubation of 8 weeks, the reductive dechlorination of PCE was observed in 7 sites among 16 sites (43%). Three enrichment cultures showed completely dechlorination of PCE to ethene, while four enrichment culture showed transformation of PCE to cis-DCE. The bacterial community structure was analyzed by PCR-DGGE. Dechlorinating bacteria were detected by species-specific primers. The dominant species in seven anaerobic enrichments were found to belong to the genus of Dehalococcoides sp. and Geobacter sp., and Dehalobacter sp.

• 한국지구물리탐사학회:학술대회논문집
• /
• 2000.09a
• /
• pp.19-40
• /
• 2000

We applied both SP monitoring and pole-pole array resistivity surveys and SP survey and dipole-dipole array resistivity survey to leakage problems in several embankments and dike, respectively, to estimate and detect the zone of leakage. The embankment is generally affected by tidal variation and has low resistivity characteristics due to the high saturation of seawater. According to this situation, SP monitoring and resistivity survey using pole-pole electrode array, which is relatively more effective to the conductive media, were carried out to delineate the leakage zones of sea water through the embankment. We checked out electrical conductivity(EC) and temperature variations along the inner part of the embankment to detect the zone of seawater leakage and found that the measured EC value agreed to that of seawater in the leakage zone and the temperature was lower than that of the vicinity of leakage zone. SP monitoring results were coincide with tidal variations at each embankment. Based on the survey results, it is concluded that both SP monitoring and the pole-pole array resistivity method are quite effective for investigation of seawater leakage zones in the embankment.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.25 no.2
• /
• pp.294-300
• /
• 1996

우리나라 남해 연안 해역으로부터 적색색소를 생산하는 균주를 분리하여 동정한 결과 Vibrio sp.로 판명되었다. 본 균주는 성장과정 중에 적색색소를 생산하여 세포내에 축적시키며 이때의 적색색소 생산량은 배양 후 24시간 이후부터 최고치에 도달하였으며, 배지중의 첨가물로서 0~2%의 NaCl, 1% fructose, 0.3%의 $(NH_{4})_{2}SO_{4}$를 첨가되었을 때 높은 생산량을 보였다. 한편 배양하여 얻어진 균체로부터 methanol로 추출한 적색색소는 UV-VIS spectrophotometer로 분석한 결과 최대 흡수파장이 531nm이였으며, 현재까지 널리 알려진 anthocyan계열의 색소와 동일한 흡수파장을 지니는 것으로 알 수 있었다. 또한 methanol 추출 색소를 TLC와 HPLC로 분리.정제하여 GC/MS로 분석한 결과 분자량 281과 236인 2종류의 물질이 검출되었으며, 281의 분자량을 가지는 물질의 경우 anthocyanin의 기본 구조에 OH기가 5개 존재하는 cyanidin으로 추정되었다. 따라서 본 실험에서 사용한 해양 유래 Vibrio sp.가 생산하는 적색색소는 cyanidin을 주성분으로 하는 anthocyan 계열의 색소이이 확인되었다. 유전공학적 기법을 이용한 균주 개량과 대량생산 체제가 구축된다면, 현재 널리 사용되고 있는 화학 합성색소를 대체할 수 있는 천연색소로서, 식품, 의약품, 화장품, 화학, 염료 공업 등에 사용될 수 있으리라 사료된다.

• Microbiology and Biotechnology Letters
• /
• v.35 no.1
• /
• pp.58-65
• /
• 2007

The role of soil microorganisms, specifically rhizobacteria, in the development of rhizoremediation techniques is important to speed up the process and to increase the rate of mobilization or absorption of heavy metals to the plant. In this study, Methylobacterium sp. SY-NiR1 was isolated from the rhizosphere soils of plants in oil and heavy metal-contaminated soil. Based on its pink pigmented colony, rod-shape cells, and belonging in $\alpha-Proteobacteria$, Methylobacterium sp. SY-NiR1 is considered a pink-pigmented facultative methylotroph. SY-NiR1 had the ability to produce indole acetic acid which is one of phytohormones. This bacterium showed resistance against multiple heavy metals such as Cd, Cr, Cu, Pb, Ni, Zn, and the order of its resistance based on $EC_{50}$ was Zn > Ni > Cu > Pb > Cd > Cr. Therefore, Methylobacterium sp. SY-NiR1 can stimulate seed germination and plant growth in soil contaminated with heavy metals.