• Journal of Broadcast Engineering
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• v.13 no.4
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• pp.479-487
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• 2008

The method to determine allowable interference criteria is required due to new digital FWSs(Fixed Wireless Systems) adding to allowable frequency bands, besides current FWSs and digital FWSs. In this paper, we suggested a method to define allowable interference between digital FWSs. Types of interference for FWS were defined and channel characteristics were analyzed. Allowable interference criteria were analyzed using the suggested method for M-ary QAM modulations, which is typical modulation technique of digital FWS.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.27 no.9
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• pp.1229-1237
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• 2003

The production of hydrogen fuel depends basically on the water electrolysis. The ultrasonic effects the decrease of the overpotential in a water electrolysis. A study on the overpotential which activates the hydrogen production is the core to elevate the hydrogen production efficiency on the principle. A pressure sensor system by a new idea is developed and applied. Solutions are 4 kinds of KOH concentration such as 0%, 10%, 20%, and 30%. Two frequency bands of the ultrasonic transducer are 28kHz and 2MHz. The directions of ultrasonic forcing are the vertical direction and the horizontal direction. The temperatures are two states, i.e., no constant and constant. Experiments are carried out sequentially in order in three cases of no ultrasonic forcing, ultrasonic forcing, and ultrasonic discontinution. In results, it is clarified that the ultrasonic effects the decrease of overpotential to elevate the efficiency of hydrogen production.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.14 no.6
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• pp.579-589
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• 1989

In this paper, planar power dividers/combiners for millimeter waves K-band or bands which can be printed on the substrates of hybrid or monolithic IC by surface mounting are designed and studied. Power dividers/combiners, and the conductor loss of microstrip lines in particualr the existing Wilkinson power dividers/combiners is modified ad amployes by ist equivalent circuit. Microwave CAD program SUPEROMPACT is employed for the Wilkinson power combiner which is modified and analyzed to reduce the high frequency coupling between the branches of the combiner, and the method to diminish the sensitivity of the input reflection of $2^n$-way power dividers/combiners is studied employing the commerical microwave CAD program package SUPERCOMPACT.

• KIEAE Journal
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• v.12 no.1
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• pp.73-81
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• 2012

Floor impact sound has been most annoying for years among the noises which are produced in apartment. This study aims to analyze the improvement of floor impact sound by comparing the results of the test which was carried out for the wall slab type apartment and moment frame apartment, and also for the effect of advanced vibration isolation layer. Moment frame structure that main structure consists of column and slab has shown better performance for the heavyweight impact sound comparing with wall slab type structure which is general type in Korea. Stiffness of floor system was raised by reinforcing the stiffness of vibration isolation layer, and it was analyzed how much the floor impact sound performance was improved. The result showed that the reinforced floor had better performance than the existing floor system that uses lightweight porous concrete as vibration isolation material. In addition, a system used wire mesh in mortar showed improvement of floor impact sound than a system without wire mesh, and better performance for the frequency bands lower than 160 Hz which causes floor impact problem in wall slab type apartment.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.11A
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• pp.1085-1090
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• 2010

Ultra wideband (UWB) technologies have been developed to exploit a new spectrum resource in substances and to realize ultra-high-speed communication, high precision geolocation, and other applications. The energy of UWB signal is extremely spread from near DC to a few GHz. This means that the interference between conventional narrowband systems and UWB systems is inevitable. However, the interference effects had not previously been studied from UWB wireless systems to conventional mobile wireless systems sharing the frequency bands such as Cellular CDMA and Korean PCS. This paper experimentally evaluates the interference from two kinds of UWB sources, namely a direct-sequence spread-spectrum UWB source and an impulse radio UWB source, to a Cellular CDMA and K-PCS digital transmission system. The average frame error rate degradation of each system arc presented. From these experimental results, we show that in all practical cases UWB system can coexist with Cellular CDMA and K-PCS terminal without causing any dangerous interference.

• Atmosphere
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• v.22 no.3
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• pp.381-386
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• 2012

The monthly number of days with rain or snow in Seoul extends backward to 1626 from the present. The number of rain and snow days are from the ancient records and combined with the modern precipitation records from 1907 to the present. There are two distinct and abrupt changes in the time series, which allow us to divide the entire period into three sub-periods of CR-I, CR-II, and MR. For each sub-period, we calculated the basic statistics and the associated distributions. The analysis proves Seoul, which may comprise East Asia when considering the lengthy period of dry condition, had dry climate for the Maunder Minimum when Europe experienced cold climate. We also note relationships between the rain days and sunspot numbers in various frequency bands.

• Korean Journal Plant Pathology
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• v.13 no.2
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• pp.90-94
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• 1997

Interaction of races of rice blast fungus and cultivars has been evaluated. Dongjinbyeo was infected by four KJ races and two KI races, while other varieties were susceptible to four to six KJ or KI races. Among the single spores reisolated from the leaf blast lesion of Dongjinbyeo after mixed inoculation of 10 races, 63% was race KJ-301 which produced a small number and small size lesions, while 30% was race KI-313 which produced a large number of lesions. However, 93% of single spores reisolated from Palgongbyeo was a highly virulent race KJ-105. On the other hand, all the races were equally reisolated from the susceptible cultivar Jinmibyeo. Frequency of races isolated from the naturally infected leaf blast lesions in the field was similar to that of reisolated races from the cultivars inoculated with 10 mixed races in the greenhouse. However, 30% of single spores isolated from the naturally infected Dongjinbyeo was race KI-329 ut ace KI-313 was not detected. Genetic relationship of the isolates collected from leaf and neck blast fungus of Jinmibyeo and Nakdongbyeo showed specific bands on RFLP-P64, However, their genetic similarity was 80%.

• Korean Journal of Veterinary Research
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• v.39 no.4
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• pp.811-818
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• 1999

A total of 16 Staphylococcus epidermidis isolates collected from 14 dogs admitted to the Veterinary Medicial Teaching Hospital in Seoul National University over eleven months were examined for in vitro antibiotic susceptibility pattern with minimum inhibitory concentration (MIC) and slime production, a virulence-associated phenotype, and were genetically characterized by pulsed-field gel electrophoresis (PFGE). The frequency of resistance to antimicrobial agents tested was not high, with a susceptibility ranging from 56.3% to 100%. Three strains exhibited multiple drug resistance against amikacin (MIC, $32-64{\mu}g/ml$), ampicillin ($32{\mu}g/ml$), fosfomycin ($32-128{\mu}g/ml$) and gentamicin ($16{\mu}g/ml$). Vancomycin, ciprofloxacin and rifampin were effective antibiotics against the isolates. All isolates were slime producers ; strains isolated from dogs which died of bacteremia were more likely to produce slime than those isolated from dogs which survived. Chromosomal DNA fingerprinting of the isolates yielded 16 different genomic types with few common bands, indicating a variety of clones of S epidermidis were prevalent in the hospital. This study revealed that PFGE is an useful method for the genotype characterization of S epidermidis strains and this organism could probably be pathogenic in some dogs with severe disorders. Further works on a larger number of epidemiologically defined strains are required to assess these results.

• Fashion & Textile Research Journal
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• v.13 no.1
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• pp.17-24
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• 2011

This study aims to provide basic materials for adaptive-clothing development for disabled seniors by considering the characteristics of design with both functionality and beauty, which is displayed to overseas functional clothing for disabled seniors. After 341 photographs from 15 overseas websites which sold adaptive-clothing for disabled seniors were collected, their designs were analyzed. The content analysis and frequency analysis using the descriptive statistics were performed as the analytical methods for this study. The results are as follows; first, the design of buttons uses snap fasteners, zippers, Velcro fasteners and rubber bands so as to attach easily and keep fasteners unseen. Second, the used open system is the Back open, the Side open, the Front open and the Hip open. Third, in terms of design, the change follows easy and loose silhouette in order to act comfortably outdoors as well as indoors by making the design of onepiece dresses, jackets and cardigans similar to ordinaries. From the details aspect, a few trimmings such as color, patterns, ruffles around edge, laces and smooth shirring do not stand in the way and give mental please.

• Journal of Plant Biotechnology
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• v.6 no.3
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• pp.157-163
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• 2004

An efficient system for the regeneration of adventitious shoots from in vitro cultured leaf sections of Lycium chinense Miller was developed and silent somaclones from the regenerants detected with RAPD method. Among the eight media tested (B5, SH, N&N, 1/2MS, MS, 3/2MS, GD and WPM), and four cytokinins (BA, kinetin, 2ip and zeatin) with different concentrations (1, 5, 10, 20, 30 and 40 $\mu{M}$), 1/2 MS medium supplemented with 20 and 30 $\mu{M}$ zeatin showed the best regeneration frequency (100% and 93.7%) and higher average number of shoots (9.0 and 9.4). All regenerants easily elongated after subculturing on 1/4MS without growth stimulants and produced spontaneous adventitious roots from their basal parts. With phenotypically normal 40 regenerants, RAPD analysis with 15 different random primers was performed to examine the cryptic somaclonal variants. No substantial differences in banding patterns were found in the amplified polymorphic DNAs implying no DNA changes during dedifferentiation into adventitious shoots. However, one (OPF-4) of the 15 primers detected silent somaclonal variation in one regenerant in which two different polymorphic bands did not appear when compared with the rest regenerants. The results indicate that regenerantion via intervening callus phase can be used to establish true-to-type planting stocks for homogeneous population.