• 한국통신학회논문지
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• 제29권5A호
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• pp.484-491
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• 2004

L-band EDFA는 작은 평균밀도 반전율에서 동작하기 때문에 C-b란d에서 상대적으로 높은 흡수율로 인해 펌프 효과를 가지게 된다. 본 논문에서는 980nm의 펌프 입력 광 파워, C-band 펌프 파장 및 입력 광 파워에 따라 펌프 효과에 대해 논하고자 한다. 즉, C-band 펌프광의 흡수 또는 후방 자연방출광의 흡수라는 두 가지 다른 메카니즘을 통해 펌프 효과를 야기 시키게 된다. 또한 동일한 소 신호 이득 조건 하에서 L-band 신호 입력 광에 의한 포화 특성 (포화 광출력, 잡음지수에 있어서 장파장의 C-band 펌프가 양호한 것으로 나타난다. 전광 고정이득 L-band EDFA에서 C-band발진의 효과를 검토한 결과 L-band발진에 비해서 개선된 특성은 없는 것으로 나타난다.

• 한국지구과학회지
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• 제23권1호
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• pp.1-14
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• 2002

The land-cover of two regions of South and North Korea included in one Landsat TM scene was investigated by comparing different seasons and different band data over the multiple land-cover types. The relationships between the intensities of two bands in the 2-D plot are mainly linear in band2 versus band1 and band3 versus band1, polygonal sporadic in band5 versus band1 and band7 versus band1, and almost tri-polarized in band4 versus band3. The 2-D plot of band4/band3 shows the best capability to discriminate different main land-cover such as water, vegetation and dry soil. Some discriminations are not clear between city and dry field, or mountain and plain field in the scene of September. The digital number data of band4 from vegetated zones show stronger reflectance in September rather than April, while other band values tend to be lager in April than in September over each land-cover. NDVI presents high value in both regions in September. However the image of Wonsan area in April suggests weak vigor of vegetation in comparison with Cholwon area. Band ratios are very effective in eliminating the influence of the complex topography. The proper pairing of the band ratio improved the discrimination capability of the land-cover; band5/band2 for dry soil, band4/band3 for vegetation and band1/band7 for the water. The RGB combination of the three band ratio pairs showed the best results in the discrimination of the land-cover of Wonsan, Cholwon and even the Demilitarized Zone.

• 대한의용생체공학회:의공학회지
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• 제10권2호
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• pp.131-138
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• 1989

In this paper the feature of background EEG is extracted by LS Prony Method for the analysis of background EEG in the time domain. Autocorrelation leg estimates are not required with the LS Prony method. The Prony method is required any the solution of two serfs of simultaneous linear equation and a polynominal rooting. That the optimal order of this model is the 6-th order is determined by using Akaike' s Information Criterial test. From the experimential results the alpha band amplitude is the largest among alpha band beta band theta band delta band and beta band amplitude is larger than that of the delta band and theta band. The sustained time for the alph a band, the beta band, the delta band and the theta band is 2, 3461 (sec), 0.6490(sec), 0.3120(sec), 0.7046(sec) respectively. Consequenty the alpha band is maintained in the whole subjects, the beta band, the delta band, the theta band are existed intermittently in each subjects.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1989년도 춘계학술대회
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• pp.45-49
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• 1989

In this paper the feature of background EEG is extracted by LS Prony Method for the analysis of background EEG in the time domain. From the experimential results the alpha band amplitude is the largest among bands and beta band amplitude is larger than that of the delta band and theta band. The sustained time for the alpha band, the beta band, the delta band and the theta band is 2.3461(sec), 1.8980(sec), 0.3120(sec), 0.2930(sec) respectively. Consequently the alpha band and the beta band are maintained in the whole, segment. The delta band, the theta band are existed intermittently in the segment.

• 한국작물학회지
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• 제27권1호
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• pp.55-59
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• 1982

추파성정도가 다른 과맥품종의 등숙과정중 종자단백질의 변이를 acrylamide gel 전기영동으로 조사하여 파성과 종자단백질과의 관계를 추구하였다. 1. 7% acrylamide gel의 경우, 단백질 band는 품종에 관계없이 등숙정도가 진행됨에 따라 증가하였으며 band수가 가장 많이 나타나는 출수후 38일에는 논산과: 13, 세도하다까: 15, 완주: 15개의 band를 볼 수 있었다. 2. 품종간에 큰 차이를 나타낸 단백질 구성분중 ⅰ band는 전조사기간에 걸쳐 세도하다까와 완주에서만 볼 수 있었으며 j band는 출수후 33일까지 전품종에서 볼 수 있었으나 그후 논산과에서는 관찰할 수 없었다. 3. urea 첨가 7% acrylamide gel에서의 단백질 band수는 등숙초기보다 등숙후기에 오히려 감소하였으며 7% acrylamide gel에서 보다 적었다. 4. 품종간에 질적 차이를 보인 z bandsms ⅰ band 의 경우와의 대조적으로 전등숙기간에 걸쳐 논산과에서만 흔적으로 볼 수 있었다. u band는 출수기 23일까지 전품종에 존재하였으나 그후 논산과에서는 볼 수 없었으며 x band는 u band의 경우와 반대였다. 5. 전등숙기간에 걸쳐 양절형인 세도하다까의 전기영동류형은 논산과의 것보다 완주의 것과 훨씬 비슷하였는데 이는 양절형의 유전자형이 춘파형에 더 가깝다는 것을 시사한 것 같다.

• 한국동물학회지
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• 제31권3호
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• pp.225-235
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• 1988

spirometra ernacei의 제3기 유충 plerocercoid(sparganum)를 중간숙주인 흰쥐와 종숙주인 고양이에게 감염시켜서 회수한 sparganum과 성충의 non-specific esterase와 acid,alkaline phosphatased의 분포 및 isozyme pattern 변화를 비교하기 위하여 효소조직화학적 방법과 전기영동법을 이용하여 다음과 같은 결과를 얻었다. 첫째,non-specific esterase는 sparganum과 성체의 근층과 유조직층에 많이 분포하였고 표피층에는 거의 분포가 없었다. 이의 isozyme band pattern은 sparganum에서 7개의 성체에서 8개의 isozyme band로 분리 되었는데 sparganum과 성체의 major band는 각각 3번과 4번 band였다. 둘째,acid phosphatse는 sparganum과 성체의 표피층과 근층에서 많이 부포하였고 유조직층에는 거의 분포가 없었다. isozyme band pattern은 sparganum과 성체에서 각각 3개의 band로 분리되었는데 3번 band가 major band였다.셋째, alkaline phoosphatase는 sparganum과 성체의 표피층과 근층에서 많은 분포를 보였으며 유조직층에서 더 상당한 분포가 있었다. isozyme band pattern은 sparganum에서 2개 성체에서 4개가 분리되었는데 sparganum성체 모두 2번 band가 major band였다.

• Journal of electromagnetic engineering and science
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• 제16권1호
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• pp.35-43
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• 2016

A compact ultra-wide band antenna with a quadruple band-notched characteristic is proposed. The proposed antenna consists of a slotted trapezoid patch radiator, an inverted U-shaped band stop filter, a pair of C-shaped band stop filters, and a rectangular ground plane. To realize the quadruple notch-band characteristic, a U-shaped slot, a complementary split ring resonator, an inverted U-shaped band stop filter, and two C-shaped band stop filters are utilized in this antenna. The antenna satisfies the -10 dB reflection coefficient bandwidth requirement in the frequency band of 2.88-12.67 GHz, with a band-rejection characteristic in the WiMAX (3.43-3.85 GHz), WLAN (5.26-6.01 GHz), X-band satellite communication (7.05-7.68 GHz), and ITU 8 GHz (8.08-8.87 GHz) signal bands. In addition, the proposed antenna has a compact volume of $30mm{\times}33.5mm{\times}0.8mm$ while maintaining omnidirectional patterns in the H-plane. The experimental and simulated results of the proposed antenna are shown to be in good agreement.

• Journal of Communications and Networks
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• 제10권1호
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• pp.71-78
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• 2008

We propose a sub-band spreading technique for adaptive modulation (AM) in orthogonal frequency division multiplexing (OFDM) systems in order to reduce signaling overheads and to average frequency selective fading channels causing different signal-to-noise ratio (SNR) values for subcarriers in each subband. The conventional sub-band based AM schemes can also reduce signaling overheads and complexity for allocating a resource per sub-band at a time. However, they may suffer from the channel variation in a sub-band when the sub-band size is larger than the channel coherence bandwidth (BW). The sub-band spreading at the transmitter enables the received symbols in each sub-band to have an identical reliability even in a frequency selective fading channel. We rigorously analyze the averaged SNR value at the receiver of the sub-band spreading system and the analyzed average SNR in a sub-band is used for an adaptation criterion. The proposed AM scheme outperforms the conventional sub-band based OFDM scheme without spreading, and it can yield better throughput performance than the conventional subcarrier based AM schemes when we consider the signaling overheads.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제8권7호
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• pp.2212-2230
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• 2014

Cognitive radio (CR) users, known as secondary users (SUs), should avoid interference with primary users (PUs) who own the licensed band, while trying to access it; when the licensed band is unused by the PUs. To detect PUs, spectrum sensing should be performed over in-band channels that are currently in use by SUs. If PUs return to access the band, SUs need to vacate it, disrupting the SUs' communication unless a non-utilized band is discovered. Obtaining a non-utilized band in a short period facilitate seamless communication for SUs and avoid interference on PUs by vacating from the channel immediately. Searching for a non-utilized band can be done through proactive out-of-band (OB) sensing. In this paper, we suggest a proactive OB sensing scheme that minimizes the time required to discover a non-utilized spectrum in order to continue communication. Although, the duration spent on OB sensing reduces the throughput of the CR networks that can be achieved on band being utilized, the lost throughput can be compensated in the new discovered band. We demonstrate that, the effect of our proposed scheme on the throughput owing to OB sensing is insignificant, while exhibiting a very short channel discovery time.

• Journal of the Optical Society of Korea
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• 제19권6호
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• pp.673-678
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• 2015

Terahertz dual-band frequency selective surface filters made by perforating two different rectangular holes in molybdenum have been designed, fabricated and measured. Physical mechanisms of the dual-band resonant responses are clarified by three differently configured filters and the electric field distribution diagrams. The design process is straightforward and simple according to the physical concept and some formulas. Due to the weak coupling between the two neighboring rectangle holes with different sizes in the unit cell, good dual-band frequency selectivity performance can be easily achieved both in the lower and higher bands by tuning dimensions of the two rectangular holes. Three samples are fabricated, and their dual-band characteristics have been demonstrated by a THz time-domain spectroscopy system. Different from most commonly used metal-dielectric structure or metal-dielectric-metal sandwiched filters, the designed dual-band filters have advantages of easy fabrication and low cost, the encouraging results afforded by these filters could find their applications in dual-band sensors, THz communication systems and other emerging THz technologies.