• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2011.11a
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• pp.123-124
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• 2011

최근 전송량 및 주어진 SNR(signal to noise ratio)에 따른 수신 성능을 향상시키기 위하여 다중 안테나(multi-input multi-output) 시스템에 대한 연구가 활발하게 이루어지고 있다. 다중 안테나 시스템은 이론적으로 송신 안테나 개수에 비례해서 전송량이 증가하거나 송 수신 안테나 개수에 비례하여 주어진 SNR에 따른 수신 성능을 향상시킨다. 이러한 MIMO 시스템의 서로 다른 송신단에서 서로 다른 성상을 전송할 때 효율적인 전력 할당은 시스템 성능 향상에 큰 영향을 미친다. 이에 본 논문은 4-QAM 및 16-QAM을 송 수신 안테나가 두 개인 V-BLAST 시스템에 적용하고, 전력을 다르게 할당하여 수신 시스템의 성능을 분석하였다. 이러한 서로 다른 전력 할당에 따른 성능 분석 결과를 이용하여 이동 통신 시스템에 적용하기 위한 가능성 및 활용성에 대하여 논의하였다.

• Korean Journal of Microbiology
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• v.47 no.1
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• pp.97-101
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• 2011

To isolate a novel antifungal compound, we obtained 107 kinds of endolichenic fungi from Lichen Bioresources Center and examined their antifungal capability. Two fungi EL123 and EL156 showed high antifungal activity against Candida albicans in both MYA and EMM media. Nucleotide sequence analysis and NCBI Blast analysis in ITS region including 5.8S rRNA revealed that EL123 has 95% homology with Thielavia microspora and EL156, 99% with Cryptosporiopsis diversispora which belong to Ascomycetes. It observed that EL156 formed a branched mycelium whereas EL123 formed a straight one. EL156 also produced the antifungal substance faster than EL123 when they grew on MY liquid medium.

• The Journal of the Korean Society for Microbiology
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• v.18 no.1
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• pp.59-65
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• 1983

To investigate the effects of placental serum to in vitro culture of the normal human lymphocytes the peripheral blood lymphocytes were isolated by ficoll-hypaque separation method in 20 healthy human adults. The blast transformation respone of lymphocytes to mitogens were observed by stimulation with PHA($25{\mu}g/ml$) and Con A($25{\mu}g/ml$) using RPMI 1640 media containing 20% placental serum(PS), tetal calf serum(FCS), or humans AB serum(AB). And one-way mixed lymphocyte culture test was performed between these unrelated person compounded into stimulators and responders to investigate the effect of placental serum. The following results were obtained. 1. In 20 experimental cases, these were no significant diffenence between FCS, AB, and PS in untreated control cultures. 2. In PHA-treated cultures, whereas the blast transformation rate of the FCS groups and AB groups were $40.8{\pm}4.3%$ and $44.6{\pm}4.3%$ respectively, that of PS groups were $21.7{\pm}3.4%$, Similar results were obtained in Con A-meated cultures. Therefore, placental serum inhibited the mitogenic response of lymphocytes significantly. 3. In MLC tests, stimulation index of the FCS groups and AB groups were $18.5{\pm}3.5$ and $20.1{\pm}3.3$ respectively. But placental serum inhibited MLC response of lymphocytes significantly($7.4{\pm}1.9$).

• The Journal of Korean Academy of Prosthodontics
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• v.41 no.6
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• pp.720-731
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• 2003

Statement of problem. The importance of fixture design and surface treatment. Purpose. The clinical success of dental in plants is affected by many factors such like as degree of osseointegration, the effective load dispersion for the prostheses, and a lot of attempts have been made to overcome the difficulties. In this study, efforts were made to find the possibility of clinical acceptance of the dental implants of newly designed surface and resorbable blast media surcace. Materials and methods. In this study, two groups of custom-made, screw-shaped implants were prepared. The first with the consisting of Branemark clone design and the other with the new design. These implants were divided into four groups according to the kinds of surface treatment. Four implants($AVANA^{(R)}$, Osstem, Busan, Korea)of each group were installed in twenty rabbits. Group A was consisted of Branemark done implant left as machined, Group B with Branemark clone implants with RBM(Resorbable blast media) surface, Group C with newly designed implants left as machined and Group D with newly designed implants with RBM surface. One of the twenty rabbits died from inflammation and the observation was made for six weeks. Specimens from four groups were observed using scanning electron microscopy with 40, 100, 1000 magnification power and microsurface structures were measured by white-light scanning interferometry for three dimensional surface roughness measurements(Accura $2000^{(R)}$, Intek-Plus, Korea.). Removal torque was measured in 17 rabbits using digital torque gauge(MGT 12R, Mark-10 corp., NY, U.S.A.) immediately after the sacrifice and two rabbits were used for the histologic preparation(EXAKT $310^{(R)}$, Heraeus Kulzer, wehrheim, Germany) of specimens and observed under light microscope. Resonance frequency measurement($Osstell^{(R)}$) was taken with the 19 rabbits at the beginning of the implant fixation and immediately after the sacrifice. Results. Following results were taken from the experiment. 1. The surface of the RBM implants as seen with SEM had rough and irregular pattern with reticular formation compared to that of fumed specimens showing different surface topographies. 2. The newly designed implant with RBM surface had high removal torque value among four groups with no statistical significance. The average removal torque was $49.95{\pm}6.70Ncm$ in Group A, $51.15{\pm}4.40Ncm$ in Group B, $50.78{\pm}9.37Ncm$ in Group C, $51.09{\pm}4.69Ncm$ in Group D. 3. The RFA values were $70.8{\pm}4.3Hz$ in Group A, $71.8{\pm}3.1Hz$ in Group B, $70.9{\pm}2.5Hz$, $72.7{\pm}2.5Hz$ in Group D. Higher values were noted in the groups which had surface treatment compared to the untreated groups with no statistical significance. 4. The results from the histomorphometric evaluation showed a mean percentage of bone-to-implant contact of $45{\pm}0.5%$ in Group A, $55{\pm}3%$ in Group B, $49.5{\pm}0.5%$ in Group C, and $55{\pm}3%$ in Group D. Quite amount of newly formed bone were observed at the surface RBM-treated implants in bone marrow space.

• Journal of the Korea Concrete Institute
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• v.27 no.4
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• pp.435-441
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• 2015

Concrete, as a porous media, has permeability and it is considered as a major parameter for durability evaluation. Cold joint caused by delayed placing of concrete accelerates water permeation and intrusion of harmful ions. In the paper, concrete specimens containing GGBFS (Ground Granulated Blast Furnace Slag) and OPC (Ordinary Portland Cement) are prepared with cold joint section, and water permeability and water flow at the age of 91 days are measured for 2 weeks. Sound concrete with GGBFS shows decreased permeability to 89% for sound concrete with OPC and 0.86 of decreasing ratio is evaluated in GGBFS concrete with cold joint. Through WPT (Water Penetration Test), the effects of mineral admixture and cold joint on water permeability are evaluated, and variation in water behavior via cold joint is analyzed through probabilistic method as well.

• International Commerce and Information Review
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• v.13 no.3
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• pp.55-74
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• 2011

Web Service applications based on the social relation such as Social Network Service(SNS), Social Medias are making strong blast. Social Computing which is widely spreading to worldwide is affecting to our life including policies, economies, societies and culture. Based on Web 2.0, various services like as Social Collaboration, Social Publishing, Social Feedback are supplied, more evolved social computing services, Social Connection, Augmented Reality, will be served for the next days from now. These network based services, Social Network Service or Social Media frequently used terms, are not defined exactly and their characteristics are not gotten to the bottom yet. Theoretical and systematic studies on these themes are not made also. Applications to business area, especially the receptivity to social computing in international trade is barely made to these days. This study focuses on the concepts, characteristics and sorts of social computing and purposes to consider its possibilities of application of social computing to international trade. Considering the advantage of Social network service, it can be used in international trade, a kind of B2B transaction, while existing social network is mainly applied to B2e transaction.

• Journal of the Korean Society for Railway
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• v.18 no.6
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• pp.552-557
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• 2015

Ballast gravel in a railroad field is often polluted by grease and heavy metals. In this paper, the performances of a dry cleaning method for polluted ballast gravel in which pollutants on the gravel surface can be physically removed was extensively studied. A polluted ballast cleaning device able to shoot emery blasting media onto the surface using compressed air was prepared. Polluted ballast gravel was put into this device for cleaning, with the treatment time varied from 1 to 10 min. The cleaning efficiency of the total petroleum hydrocarbons and heavy metals were studied. The total petroleum hydrocarbon removal efficiency was 70-80% for gravels sampled from a locomotive waiting line, while it was 40-60% for gravels sampled from a turnout area. The heavy metal removal efficiency exceeded 90% for copper and lead, while it was 65-80% for nickel and zinc. This system was found to be effective for the remediation of polluted ballast gravels.

• Journal of Yeungnam Medical Science
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• v.36 no.1
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• pp.43-49
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• 2019

Background: In the osseointegration of dental implants, the implant surface properties have been reported to be some of the most important critical factors. The effect of implant's surfaces created by resorbable blast media (RBM) followed by laser ablation on bone tissue reactions was examined using the removal torque test and histomorphometric analysis. Methods: Two types of dental implants, RBM-laser implants (experimental group) and RBM implants (control group) (CSM implant system, Daegu, Korea; L=6 mm, diameter=3.75 mm) were placed into the right and left distal femoral metaphysis of 17 adult rabbits. Six weeks after placement, removal torque was measured and histomorphometric analysis was performed. Results: The mean removal torque was $24.0{\pm}10.2Ncm$ and $46.6{\pm}16.4Ncm$ for the control and test specimens, respectively. The experimental RBM-laser implants had significantly higher removal torque values than the control RBM implants (p=0.013). The mean values of total and cortical bone to implant contact (BIC) were respectively $46.3{\pm}10.8%$ and $65.3{\pm}12.5%$ for the experimental group, and $41.9{\pm}18.5%$ and $57.6{\pm}10.6%$ for the control group. The experimental RBM-laser implants showed a higher degree of total and cortical BIC compared with RBM implants, but there was no statistical significance (p=0.482, 0.225). Conclusion: The removal torque and BIC of the test group were higher than those of the control group. In this study, the surface treatment created by RBM treatment followed by laser ablation appears to have a potential in improving bone tissue reactions of dental implants.

• Journal of Periodontal and Implant Science
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• v.39 no.3
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• pp.293-301
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• 2009

Purpose: The purpose of this study is to show the total survival rate of implants with maxillary sinus floor elevation and the effects that reach the survival rate by classifying types of graft materials, implant surface, operation method, bone height. Methods: In a total of 131 patients, 251 implants with sinus floor elevation were installed simultaneously or after regular healing. Various bone grafts (autograft, xonograft, allograft, alloplast) and implant surface (MTX-HA implant, chemical etching implant, Titanium oxide surface implant, resorbable blasting media implant, resorbable blast texturing implant, HA-coated implant) were used. All implants were investigated clinically and radiographically, being with 1 to 5 years follow-up period after installation. Results: The survival rate of 251 implants with maxillary sinus floor elevation was 94%. The types of implant, surface, graft material, bone height have no statistically signi-ficant differencies. Conclusions: It can be suggested that maxillary sinus floor elevation may have predictable result with various bone graft materials and implant surface.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.84.2-85
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• 2003

Magnaporthee grisea causes the devastating blast disease of rice. Entensive research has been conducted on infection mechanisms, particularly on appressorium formation and penetration, of this fungus during the last decade. However, the role(s) of cell-wall-degrading enzymes (CWDEs) on pathogenesis is not clearly demonstrated at molecular level. Many CWDES in plant pathogenic fungi including M. grisea are redundant; that is, there are multiple genes encoding enzymes with a similar or overlapping spectrum of activities. It is laborious to isolate all of the genes encoding related enzymes and to construct mutants lacking all 9f them. Thus, we considered alternative strategies to address the role of CWDEs in pathogenesis. Since expression of CWDE genes Is repressed by a simple sugar, as the first step, we cloned a Snfl (sucrose non-fermenting) gene (MgSnf1) from M. grisea. The predicted amino acid sequence showed a high identity with other Snf1 genes from various fungi. To elucidate molecular function of MgSnf1, a transformant lacking MgSnf1 was created by targeted gene replacement. En glucose, sucrose, and xylan the MgSnf1 mutant grew normally but in pectin and complex media, it grew slower than wild type. Expression of various CWDEs in MgSnf1 mutant was investigated and found that expression of some CWDEs is repressed. However, no significant difference was observed in conidial germination, appressorium formation, and pathogenicity in MgSnf1 mutant. However, MgSnf1 functionally complemented a yeast MgSnf1 mutant. These results suggest that MgSnf1 is involved in regulation of CWDEs and MgSnf1 is dispensable in pathogenicity of M. grisea.