• Journal of Communications and Networks
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• v.13 no.4
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• pp.327-338
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• 2011

With the incitation to reduce power consumption and the aggressive reuse of spectral resources, there is an inevitable trend towards the deployment of small-cell networks by decomposing a traditional single-tier network into a multi-tier network with very high throughput per network area. However, this cell size reduction increases the complexity of network operation and the severity of cross-tier interference. In this paper, we consider a downlink two-tier network comprising of a multiple-antenna macrocell base station and a single femtocell access point, each serving multiples users with a single antenna. In this scenario, we treat the following beamforming optimization problems: i) Total transmit power minimization problem; ii) mean-square error balancing problem; and iii) interference power minimization problem. In the presence of perfect channel state information (CSI), we formulate the optimization algorithms in a centralized manner and determine the optimal beamformers using standard convex optimization techniques. In addition, we propose semi-decentralized algorithms to overcome the drawback of centralized design by introducing the signal-to-leakage plus noise ratio criteria. Taking into account imperfect CSI for both centralized and semi-decentralized approaches, we also propose robust algorithms tailored by the worst-case design to mitigate the effect of channel uncertainty. Finally, numerical results are presented to validate our proposed algorithms.

• Journal of Plant Biology
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• v.37 no.1
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• pp.53-67
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• 1994

The opal phytolith types in Oryza sativa L. were examined with light and scanning electron microscope, and we suggested the standard tenninoligies based on original cells of the phytoliths in situ. The distinctive fonus of opal phytoliths were observed in all plant parts such as leaf blade, leaf sheath, culm, root, glume, lemma, and palea. The phytolith fonus originated from long cell, short cell, and dennal appendages were different from part to part. The opal phytoliths derived from the long cells showed the most various form: twelve types were identified based on side wall shape. The results showed that the leaf blade did include almost all types of opal phytolith observed in the other parts of rice.f rice.

• Journal of Microbiology
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• v.33 no.4
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• pp.328-333
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• 1995

$\^$31/ P-NMR experiment was performed to detect phophonates (Pn) utilization and degradation in the several different C-P lyase mutants of E. coli and in E. aerogenes and the recombinants. The relative peak intensity (RPI) for the standard samples of 0.5 mM methylphosphonate (MPn) and 1.0 mM aminoethylphosphonate in glucose-MOPS medium showed 0.5 : 1.0 ratio. In the case of BW14329 (.DELTA.phnC-P, .delta.phoA), RPI did not change significantly after 24 hrs culturing, which means it nearly could not utilize Pn. In vivo $\^$31/ P-NMR spectrum of E. aerogens (BWKL 16627) during 3 hrs starvation showed two intense peaks at 0-2 ppm and at near-10 ppm which indicate intracellular orthophosphate (Pi) and pyrophosphate (PPi), respectively. Both of them might be released by degradation of inorganic polyphosphate pool. When MPn is supplied to the medium as an unique P source, Pi content in the cell has the constant, but PPi seems to be slightly decreased. Recombinants (BWKL 16954) grew slower than E. aerogenes in the glucose-MOPS media with various P sources. In vivo $\^$31/ P-NMR spectrum of recombinant did not show any intense signal in the cell. Surprisingly, under the cultivation adding with MPn, a few intense peaks in the region of Pi AND phospate monoester were detected.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.10A
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• pp.1529-1539
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• 2000

The contact procedure of access channel necessary to set up the originating call has a close relation with the performance and capacity of the base station system in CDMA cellular network. This paper investigates the structure and the operation of the backward channel of IS-95 CDMA standard and explains the related system parameters. We can derive the throughput of the CDMA access channel depending on the arrivals of the access probes per access channel slot, given the system parameters such as cell radius, the maximum number of retransmission, and the error rates of the access and paging channel. It shows that the performance in throughput is much better in the CDMA IS-95 access channel than in the slotted aloha channel. It also gives the reasonable number of the trafic channels in a cell with the given blocking probability.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.13 no.8
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• pp.783-789
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• 2002

In this paper, V-band MMIC coupled oscillator arrays are presented. In the proposed array, two push-pull patch antennas are synchronized by using strong electromagnetic coupling between two antennas. As a result, total size of the array is reduced and the array can be integrated in a single chip. To verify proposed array concept, two 1$\times$2 arrays are designed and fabricated using standard 0.15 um gate length pHEMT MMIC process. The circuits are mounted in an oversized waveguide and measured. The first array shows 0.5 dBm at 56.372 GHz and the second one has an output of 5.85 dBm at 60.147 GHz.

• Journal of the Korean Ceramic Society
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• v.49 no.6
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• pp.637-641
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• 2012

Due to its high production cost and relatively high energy consumption during the Siemens process, poly-silicon makers have been continuously and eagerly sought another silicon route for decades. One candidate that consumes less energy and has a simpler acidic and metallurgical purification procedure is upgraded metallurgical-grade (UMG) silicon. Owing to its low purity, UMG silicon often requires special steps to minimize the impurity effects and to remove or segregate the metal atoms in the bulk and to remove interfacial defects such as precipitates and grain boundaries. A process often called the 'gettering process' is used with phosphorus diffusion in this experiment in an effort to improve the performance of silicon solar cells using UMG silicon. The phosphorous gettering processes were optimized and compared to the standard POCl process so as to increase the minority carrier lifetime(MCLT) with the duration time and temperature as variables. In order to analyze the metal impurity concentration and distribution, secondary ion mass spectroscopy (SIMS) was utilized before and after the phosphorous gettering process.

• Mycobiology
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• v.45 no.4
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• pp.385-391
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• 2017

The ability of Bacillus subtilis, strain ALICA to produce three mycolytic enzymes (chitinase, ${\beta}$-1,3-glucanase, and protease), was carried out by the chemical standard methods. Bacillus subtilis ALICA was screened based on their antifungal activity in dual plate assay and cell-free culture filtrate (25%) against five different phytopathogenic fungi Alternaria alternata, Macrophomina sp., Colletotrichum gloeosporioides, Botrytis cinerea, and Sclerotium rolfesii. The B. subtilis ALICA detected positive for chitinase, ${\beta}$-1,3-glucanase and protease enzymes. Fungal growth inhibition by both strain ALICA and its cell-free culture filtrate ranged from 51.36% to 86.3% and 38.43% to 68.6%, respectively. Moreover, hyphal morphological changes like damage, broken, swelling, distortions abnormal morphology were observed. Genes expression of protease, ${\beta}$-1,3-glucanase, and lipopeptides (subtilosin and subtilisin) were confirmed their presence in the supernatant of strain ALICA. Our findings indicated that strain ALICA provided a broad spectrum of antifungal activities against various phytopathogenic fungi and may be a potential effective alternative to chemical fungicides.

• Korean Journal of Pharmacognosy
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• v.24 no.4
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• pp.289-295
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• 1993

Polysaccharides fractions from the leaves of Artemisia selengensis$(ASP_1)$ and Artemisia iwayomogi$(ASP_1)$ were extracted and purified by Sephadex gel filtration and DEAE-Sephadex ion exchange chromatographies. Both $ASP_1$ and $AIP_1$ fractions were tested for their effects on the spleen cell culture in vitro. Both $ASP_1$ and $AIP_1$ fractions allow growth of spleen cells up to 3 months in culture, suggesting the immunoregulatory activities of those polysaccharide fractions. The molecular weights of $ASP_1$ and $ASI_1$ fractions were found to be about 2,500 daltons by Sephadex gel filtration chromatography using standard dextrans. Both $ASP_1$ and $AIP_1$ fractions were composed of glucose, xylose and galactose.

• 한국신재생에너지학회:학술대회논문집
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• 2006.06a
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• pp.152-153
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• 2006

The new approach to buffer layer design for CIGS solar cells that permitted to reduce the buffer absorption losses in the short wavelength range and to overcome the disadvantages inherent to Cd-free CIGS solar cells was proposed. A chemical bath deposition method has been used to produce a high duality buffer layer that comprises thin film of CdS and Zn-based film. The double layer was grown on either ITO or CIGS substrates and its morphological, structural and optical properties were characterized. The Zn-based film was described as the ternary compound $ZnS_x(OH)_y$. The composition of the $ZnS_x(OH)_y$ layer was not uniform throughout its thickness. $ZnS_x(OH)_y$/CdS/substrate region was a highly intermixed region with gradually changing composition. The short wavelength cut-off of double layer was shifted to shorter wavelength (400nm) compared to that (520 nm) for the standard CdS by optimization of the double buffer design. The results show the way to improve the light energy collection efficiency of the nearly cadmium-free CIGS-based solar cells.

• Biomedical Science Letters
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• v.24 no.4
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• pp.292-304
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• 2018

Microbes is becoming increasingly forensic possibility as a consequence of advances in massive parallel sequencing (MPS) and bioinformatics. Human DNA typing is the best identifier, but it is not always possible to extract a full DNA profile namely its degradation and low copy number, and it may have limitations for identical twins. To overcome these unsatisfactory limitations, forensic potential for bacteria found in evidence could be used to differentiate individuals. Prokaryotic cells have a cell wall that better protects the bacterial nucleoid compared to the cell membrane of eukaryotic cells. Humans have an extremely diverse microbiome that may prove useful in determining human identity and may even be possible to link the microbes to the person responsible for them. Microbial composition within the human microbiome varies across individuals. Therefore, MPS of human microbiome could be used to identify biological samples from the different individuals, specifically for twins and other cases where standard DNA typing doses not provide satisfactory results due to degradation of human DNA. Microbial forensics is a new discipline combining forensic science and microbiology, which can not to replace current STR analysis methods used for human identification but to be complementary. Among the fields of microbial forensics, this paper will briefly describe information on the current status of microbiome research such as metagenomic code, salivary microbiome, pubic hair microbiome, microbes as indicators of body fluids, soils microbes as forensic indicator, and review microbial forensics as the feasibility of microbiome-based human identification.