• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.18 no.7
• /
• pp.704-709
• /
• 2007

In this paper, a CPW band-pass filter with a rejection band is proposed for UWB(Ultra-Wideband) communication systems. The proposed filter has a band-pass characteristic of wide-band by inserting only a slot in $50{\Omega}$ transmission line. To obtain the band-rejection function at WLAN frequency band($5.15{\sim}5.725GHz$), the designed filter is combined with folded slot resonators on the ground plane of the CPW structure. The fabricated CPW band-pass filter shows a compact size of $15.35{\times}13.60mm$, a wide passband of 2.8 GHz to 9.8 GHz and the narrow stop-band of 5.15 GHz to 5.71 GHz for 3-dB bandwidth. Also, the measured group delay is less than 400 psec throughout the operation frequency band except the rejection band.

• The Journal of the Acoustical Society of Korea
• /
• v.22 no.1
• /
• pp.35-41
• /
• 2003

Feature vectors for conventional speech recognition are usually extracted in full frequency band. Therefore, each sub-band contributes equally to final speech recognition results. In this paper, feature Teeters are extracted indepedently in each sub-band. The cepstral resolution of each sub-band feature is controlled for the optimal speech recognition. For this purpose, different dimension of each sub-band ceptral vectors are extracted based on the multi-band approach, which extracts feature vector independently for each sub-band. Speech recognition rates and clustering quality are suggested as the criteria for finding the optimal combination of sub-band Teeter dimension. In the connected digit recognition experiments using TIDIGITS database, the proposed method gave string accuracy of 99.125%, 99.775% percent correct, and 99.705% percent accuracy, which is 38%, 32% and 37% error rate reduction relative to baseline full-band feature vector, respectively.

• The Korean Journal of Zoology
• /
• v.22 no.1
• /
• pp.1-10
• /
• 1979

From the experimental results of cellulose acetate membrane electrophoresis we concluded the followings in explaining the LDH isozyme patterns found in the retina and cerebrum of vertebrata. Lactate dehydrogenase of the retina and cerebrum of both Carassinus carassinus and Cyprinus carpio was found to have one diffused band located between $LDH_2$ and $LDH_1$. LDH isozyme patterns of heart, pectoral muscle, liver and stomach of the Cyprinus carpio had the same diffused band in all organs. LDH isozyme patterns of the cerebrum of Hynobius leechii and Rana nigromaculata were observed to be different, in Hynobius leeichi a single band moved to the negative pole and two bands of $LDH_5$ and $LDH_4$ were obtained in the Rana nigromaculata. The retina and cerebrum of Natrix tigrina lateralis were observed as one band but amyda maakii had different LDH isozymes of the retina and cerebrum. The retina of Amyda maakii had five distinct LDH isozyme bands which had decreasing activity in the order of $LDH_5, LDH_4, LDH_3, LDH_2 and LDH_1$. The cerebrum of Amyda maakii had one band like Natrix tigrina lateralis but it moved to the negative pole. LDH isozymes in the retina and cerebrum of Gallus gallus domesticus and Melopsittacus undulatus showed one band. Five characteristic LDH isozyme bands were obtained from the retina of mammals, Oryctolagus cuniclus, Canis familiaris, Sus scrofa bos taurus and in the cerebrum of mouse, albino rat, Rhinolophus ferrum-equinum kokai.

• Journal of electromagnetic engineering and science
• /
• v.10 no.1
• /
• pp.39-44
• /
• 2010

In this paper, a compact wideband antenna with a band-notch function is proposed. It operates over the UWB band with a band-stop characteristic. To increase the impedance bandwidth, a ring-shaped radiator is used. By attaching a circular stub to the ring-shaped radiator, the band-notch performance is obtained. The proposed antenna operates over a frequency range from 2.7 GHz to 11 GHz to satisfy the 10-dB return-loss requirement and provides band-stop performance in the frequency band from 5.15 GHz to 6.1 GHz. Experimental results reveal that the proposed antenna exhibits good radiation performance and is suitable for UWB applications.

• Proceedings of the KSRS Conference
• /
• 2008.10a
• /
• pp.332-335
• /
• 2008

Newly developing SAR (Synthetic Aperture Radar) sensors commonly include high resolution X-band those data are expected to contribute various applications. Recent few studies are presenting potential of X-band SAR data in forest related application. This study tried to investigate the relationship between forest stand parameters and multi-band SAR normalized backscattering. Multi-band SAR data was radiometric corrected to compare signal from different forest stand condition. Then correlation coefficients were estimated between attribute of forest stand map and normalized backscattering coefficients. Although overall correlation coefficients are not high, only X-band shows strong relationship with DBH class than other bands. The signal of C- and L-band is composed of a large number of discrete tree components such as leaves, stems, even background soil. In forest, strength of radar backscattering is affected by complex parameters. Further study might be considered more various forest stand parameters such as canopy density, stand height, volume, and biomass.

• Journal of Korea Society of Digital Industry and Information Management
• /
• v.16 no.1
• /
• pp.93-98
• /
• 2020

Research on underwater sensor networks is increasing due to such reasons as marine resource management, maritime disaster prediction and military protection. Many underwater sensor networks performs wireless communication using an acoustic sound wave band signal having a relatively low frequency. So the digital part of their modem can take charge of carrier band signal processing. To enable this, the sampling rate of the baseband band signal should be increased to a sampling rate at which carrier band signal processing is possible. In this paper, we designed a sampling rate increasing circuit based on a CIC interpolator for underwater sensor nodes. The CIC interpolator has a simple circuit structure. However, since the CIC interpolator has a large attenuation of the pass band and a wide transition band, an inverse sinc LPF is added to compensate for frequency response of the CIC interpolator. The proposed interpolator was verified in time domain and frequency domain using ModelSim and Matlab.

• Journal of Digital Contents Society
• /
• v.7 no.1
• /
• pp.41-45
• /
• 2006

In this paper, we introduced the dual-band and multi-band slot loaded patch antenna for multi services. This antenna has the characteristic of dual-band and multi-band antenna by 4 slots nearly located in the edges of a patch. By changing the number and location of probe, the width and length of slot, and the distance between slot and the edge of patch, we studied the performance of dual-band and multi-band characteristic.

• Journal of the Korean Ceramic Society
• /
• v.31 no.1
• /
• pp.11-16
• /
• 1994

The impedance matching solution map is not a sufficient method for designing the broad-band absorber because of its difficulty to get numerical data about practical band-width. Therefore, we develope a new method to design the broad-band absorber. The complex permeability limits, which is necessary for designing the broad-band absorber in C-X band (4 GHz~12.4 GHz) were investigated and application was also examined. The complex permeability limits represent the frequency dependence of the complex permeability at a practical frequency band. These complex permeability limits can be used effectively to design broad-band single-layered absorber because they offer numerical data about the band-width in the case of various dielectric loss tangent, practical frequency bands and permitted reflection losses of an absorber.

• The Bulletin of The Korean Astronomical Society
• /
• v.46 no.1
• /
• pp.38.2-38.2
• /
• 2021

We, on behalf of Korean Gemini Office (KGO), present the comprehensive knowledge on the Gemini Band 3 program and introduce KGO's activities to promote research of Korean community utilizing Band 3 programs. We first describe the role and realities of Band 3 programs in comparison with Band 1 and 2. Then, we will provide useful suggestions for preparing Band 3 programs and introduce a few selected cases that successfully use the Band 3 time. In addition to Band 3, we will briefly summarize other proposal opportunities including the Fast Turnaround and Poor Weather Proposals.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2007.06a
• /
• pp.123-124
• /
• 2007

A silver indium sulfide ($AgInS_2$) epilayer was grown by the hot wall epitaxy method, which has not been reported in the liteniture. The grown $AgInS_2$ epilayer has found to be a chalcopyrite structure and evaluated to be high quality crystal. From the photocurrent measurement in the temperature range from 30 K to 300 K, the two peaks of A and B were only observed, whereas the three peaks of A, B, and C were seen in the PC spectrum of 10 K. These peaks are ascribed to the band-to-band transition. The valence band splitting of $AgInS_2$ was investigated by means of the photocurrent measurement. The temperature dependence of the energy band gap of the $AgInS_2$ obtained from the photocurrent spectrum was well described by the Varshni's relation, $E_g(T)=\;E_g(0)\;eV-(7.78\;{\times}\;10^{-4}\;eV/K)T^2/(T\;+\;116\;K\;K)$. Also, Eg(0) is the energy band gap at 0 K, which is estimated to be 2.036 eV at the valence band state A and 2.186 eV at the valence band state B.