• Journal of the Institute of Convergence Signal Processing
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• v.7 no.3
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• pp.130-135
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• 2006

There have been experiments dealing with the possibility of the actualization of the ANC system by means of operating the DSP adaptation filter. This filter is composed of various filters(including X-LMS algorithm, Filter-U algorithm, and Full-Feedback-Filter-U algorithm) that use ventilation fans and loudspeakers as a primary source in a circular duct as an experimental device. In this operation, the ANC system using the X - LMS algorithm was found to be more effective in reducing noise than without such system. When applying the input signal of the DSP board Full Feedback-Filtered-U algorithm system while having in mind that the additionally installed second control signal was gone through feedback and mixed into the detection microphone installed near the ventilation fan when using the first ventilation fan, the system was not emitted, but maintained stable during the operation of the control filter. At this point, noise tended to decrease at a maximum of l0dB compared to other algorithms at the frequency band of 170-250Hz.

• Journal of the Korean Magnetics Society
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• v.9 no.3
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• pp.127-130
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• 1999

The magnetism and electronic structure of Ru monolayer with square lattice is investigated using the FLAPW band method. The dependence of total energies on the lattice constant was calculated for three magnetic states, i.e.,para-,ferro-, and antiferromagnetic ones. It was found that there is no energy difference between para-and antiferromagnetic states for all the lattice constant. The possibility of antiferromagnetism in square Ru monolayer is thus excluded. The ferromagnetic state is most stable for the lattice constants greater than 7.30 a.u. The energy minimum is found at the lattice constant of 6.53 a.u. Where it is paramagenetic. It is calculated that the magenetic moment is 2.49 ${\MU}_B$ at 7.72 a.u., which is close to the lattice constant of Ag. The magnetic moment is almost saturated to be ${\MU}_B$ at the lattice constant of 7.86 a.u.

• The Bulletin of The Korean Astronomical Society
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• v.40 no.1
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• pp.78.3-78.3
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• 2015

About 70 high redshift quasars with $z{\geq}5$ have been discovered through combinations of standard broad-band filters to distinguish them from contaminating sources. However, among the discovered quasars so far, there is a redshift gap at $5{\leq}z{\leq}6$ due to the limitation of traditional filter sets and selection techniques. To understand the early mass growth of supermassive black holes and the final stage of the cosmic reionization, it is important to find a statistically meaningful sample of quasars with various physical properties. Here we suggest a new selection technique of high redshift quasars using medium-band filters: nine filters with bandwidths of 50nm and central wavelengths from 625 to 1025nm. Photometry with these medium-bands traces the spectral energy distribution (SED) of a source, similar to spectroscopy with R~15. We installed these filters to SED camera for QUasars in EArly uNiverse (SQUEAN) on the 2.1m telescope at McDonald Observatory, and conducted test observations of known high redshift quasars at $4.7{\leq}z{\leq}6.1$ and also dwarf stars for comparison. We found differences in SED shapes between high redshift quasars and dwarf stars, determined their locations on color-color diagrams, and demonstrated that the medium-band filters can enhance the efficiency of selecting robust quasar candidates in this redshift range. In this poster, we propose an effective selection method of high redshift quasars using these medium-band filters and discuss its effect on our high redshift quasar survey.

• Korean Journal of Remote Sensing
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• v.22 no.1
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• pp.25-40
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• 2006

Synthetic aperture radar (SAR) from satellites provides the opportunity to regularly incorporate microwave information into forest classification. Radar backscatter can improve classification accuracy, and SAR interferometry could provide improved thematic information through the use of coherence. This research examined the potential of using multi-temporal JERS-l SAR (L band) backscatter information and interferometry in distinguishing forest classes of mountainous areas in the Northeastern U.S. for future forest mapping and monitoring. Raw image data from a pair of images were processed to produce coherence and backscatter data. To improve the geometric characteristics of both the coherence and the backscatter images, this study used the interferometric techniques. It was necessary to radiometrically correct radar backscatter to account for the effect of topography. This study developed a simplified method of radiometric correction for SAR imagery over the hilly terrain, and compared the forest-type discriminatory powers of the radar backscatter, the multi-temporal backscatter, the coherence, and the backscatter combined with the coherence. Statistical analysis showed that the method of radiometric correction has a substantial potential in separating forest types, and the coherence produced from an interferometric pair of images also showed a potential for distinguishing forest classes even though heavily forested conditions and long time separation of the images had limitations in the ability to get a high quality coherence. The method of combining the backscatter images from two different dates and the coherence in a multivariate approach in identifying forest types showed some potential. However, multi-temporal analysis of the backscatter was inconclusive because leaves were not the primary scatterers of a forest canopy at the L-band wavelengths. Further research in forest classification is suggested using diverse band width SAR imagery and fusing with other imagery source.

• Proceedings of the Korea Technology Innovation Society Conference
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• 2005.05a
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• pp.46-59
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• 2005

After the IMF jurisdiction period, the Korean economy experienced a venture boom. Korean venture enterprises had been recognized that high profitable and high technology capacity based. These ventures also have contributed to national added value tolerably. In particular, Korean information technology (IT) venture companies got away the order of economy concentrated big companies, which were taken the opportunity of new economy to make suggestion of the future courses and to open an e-Korea era. However, IT ventures firms or dotcom enterprises have had difficulties through sinking down their bubbles and slumping technology sector from the first half of the 2000. In consideration of Korea IT venture companies' conditions, Korean government introduce new national vision in order to go ahead of intelligence based society form knowledge based. Korea is planning new investment to meet with the challenge of globalization proactively by national band named u-Korea. As following a step in IT infrastructure, it will give Korean IT ventures new demand creative technologies and services by new technological windows of opportunity. This situation is expected that will become an economic take-off. This paper will look for the way to stimulate Korean IT ventures' competence and present new frontier of IT ventures turnaround.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.3
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• pp.634-639
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• 2007

Despite continuous changes these days, exhibit management methods have not changed that much. To solve th problem, some systems like bar code, color code, IrDA, etc. are being used, but still many problems remain. For the problem-solving, "Exhibt Management System with RFID" is designed and its prototype is developed, which can reduce resources and efforts to manage exhibits through that an operator confirms exhibit information and inputs any damage on the exhibit on the site by using RFID system. The system purposes to improve efficiency of exhibit management by allowing an operator to check all information of exhibitions in real time using a portable reader that recognizes tags of 900MHz band manually attached to each exhibit.

• Journal of Radiation Industry
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• v.4 no.1
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• pp.65-71
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• 2010

Two chitinase producing strains CHI2 and CHI4 were isolated from soybean rhizosphere soil. Both the strains belonged to Lysobacter enzymogenes as indicated by 16S rDNA sequence analysis. Though strain CHI2 and CHI4 produced extracellular chitinase, they differ in their chitinolytic activity. CHI4 produced approximately three times the higher amounts of enzyme than that of CHI2 under specified conditions. CHI2 produced $535.67U\;l^{-1}$ of chitinase after 48 h incubation with a specific activity of $3.91U\;mg^{-1}$ of protein while strain CHI4 produced $1584.13U\;l^{-1}$ of chitinase with a specific activity of $10.88U\;mg^{-1}$ protein. SDS-PAGE analysis indicated that the molecular weight of chitinase enzyme was approximately 45 kDa. A faint band with a molecular weight of 55 kDa reveals the possibility for the presence of another kind of chitin binding protein. Mutant library was developed by exposing the isolates to gamma rays at their $LD_{99}$ value (0.23 kGy). Totally, 11 mutants of CHI2 and CHI4 are reported to have enhanced chitinase activity. Several leaky mutant clones with decreased enzyme activity and a defective mutant (CHI2-M16) with complete loss of chitinase activity were also identified. CHI4-M18, CHI4-M8 and CHI4-M29 showed 78.8, 41.5, and 31.9% increased chitinase activity over wild type CHI4.

• Journal of electromagnetic engineering and science
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• v.10 no.1
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• pp.28-34
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• 2010

This paper introduces a new U.S. ultra-wideband(UWB: 3.1~10.6 GHz) 1:2 power divider based on a single section Wilkinson type configuration. The divider provides very flat in-band power splitting, high isolation, low insertion loss, sharp roll-off bandpass filtering, and DC blocking characteristics. The circuit consists of a $\lambda$/4 Y resonator, three capacitively coupled $\lambda$/2 short-circuited lines, and a resistor between the two output ports. The circuit structure was simulated with ADS and HFSS, and realized with low-temperature co-fired ceramic(LTCC) green tape, which has a dielectric constant of 7.8. $|S_{11}|$ better than 10 dB, $|S_{21}|$ and $|S_{31}|$ less than 3.2 dB, with both $|S_{22}|$ and $|S_{32}|$ measured as better than 12 dB for the whole UWB band. Measurement results agree closely with HFSS simulation results. The power divider has a compact size of $4\times9\times0.6mm^3$.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.5 no.6
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• pp.1045-1049
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• 2001

Wireless LANs in the 2.4 ㎓ ISM- band create a new Electromagnetic Compatibility (EMC) problem. We investigated the interference characteristics between such wireless LANs in the case of identical systems, systems with different technical parameters for modulation and demodulation, and using a Gaussian noise source as a disturbance source. Experimental results show that higher throughput is obtained when adjacent wireless LANs use different systems, and that interference characteristics can be evaluated experimentally using a Gaussian noise source. Calculated BER characteristics for the interference agree with experimental measurements, indicating that this calculation method can be used for the design of the wireless LAN network to avoid interference. It is possible to construct an efficient wireless LAN network by combining different wireless LAN systems.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.6
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• pp.1227-1232
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• 2011

Using the notch and isolation, we investigated the insertion loss and isolation characterics of the fabricated dielectric duplexers and bandpass filters for CDMA and W-CDMA dualband. Insertion loss(Tx band) and isolation(between Tx and Rx) of duplxer were about -2.1708dB and 45dB at CDMA band, respectively. Also, in the case of W-CDMA, the insertion loss(Tx band) and isolation(between Tx and Rx) showed about -2.6946 and 100dB, respectively. Summering the aboved results, fabricated the dielectric duplexers and bandpass filters will be contributed the increase of atttenuation and the decrease of interference at CDMA and W-CDMA dualband.