• Proceedings of the IEEK Conference
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• 2000.06a
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• pp.209-212
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• 2000

In this paper, effect of imperfect power control on performance of a pseudonoise (PN) code tracking loop is analyzed and simulated for a direct-sequence/code-division multiple access (DS/CDMA) system. The multipath fading channel is modeled as a two-ray Rayleigh fading model. Power control error is modeled as a log-normally distributed random variable. The tracking performance of DLL (delay-locked-loop) is evaluated in terms of tracking jitter and mean-time-to-lose-lock (MTLL). From the simulation results, it is shown that the PN tracking performance is very sensitive to the power control error.

• Proceedings of the IEEK Conference
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• 2000.11a
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• pp.461-464
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• 2000

본 논문에서는 위성통신 환경에서 DS/CDMA DPSK 시스템의 성능을 분석한다. 성능분석의 척도로 비트오류확률을 사용한다. 위성전송로는 쉐도잉이 있는 라이시안 페이딩 전송로로 모델링한다. 수치계산의 결과, 위상잡음이 존재할 때 비트오율 성능이 저하되므로 시스템 용랑이 감소될 것이 예상된다. 또한 위성전송로에서는 쉐도잉이 시스템 전체 성능에 커다란 영향을 미침을 알 수 있다. 본 논문에서의 분석은 DS/CDMA 기반의 위성통신 시스템 설계에 적용할 수 있다.

• 한국정보통신설비학회:학술대회논문집
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• 2004.08a
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• pp.142-146
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• 2004

과거와 달리 21세기의 도래로 주변에 많은 전산화 및 정보화작업이 이루어지면서 데이터 트래픽이 폭발적으로 증가하고, 정보 통신망은 이를 수용하기 위해서 전반적인 큰 변화를 겪어 왔으며 현재도 겪고 있는 중이다. 또한 정보의 중요성을 인식하면서 부터 많은 기업들이나 개인들이 정보의 손실을 의식하고 있으며 정보를 안전하게 저장하고 원활하게 활용할 수 있는 방법을 모색하게 되면서 SAN(Storage Area Network)에 대한 의존도가 높아지게 되었다. 본 고는 현재 사용도 가 높아지고 있는 Fibre Channel을 이용한 SAN전송로의 구성 및 동향에 대하여 살펴본다.

• 한국정보통신설비학회:학술대회논문집
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• 2005.08a
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• pp.180-183
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• 2005

광주파수에서 대역을 나누어주는 광필터를 이용하여, 기존의 2 코어를 이용한 단방향 광통신을 1 코어를 이용한 양방향 통신으로 전환하여 광선로 절감효과를 얻을 수 있다. 그러나 그런 양방향 통신에서 CWDM (coarse wavelength-division multiplexing) 광채널들에 대한 채널 감시가 요구된다. 정확한 정보전달을 위하여 광원의 특성을 모니터하고, 또한 보드의 신호 레벨에서 감시를 통하여 신호의 오전달을 감시한다. 본 발표논문에서는 광선로 절감에 따른 CWDM 광채널의 성능 개선을 위한 감시기술에 대하여 설명하고, 망교체시에 다른 선로에 영향을 최소로 하는 적절한 감시기술을 설명한다.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.271-272
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• 2008

TD-SCDMA combines TDMA and CDMA components to provide more efficient use of radio resources, and includes a new feature called HSDPA (high-speed downlink packet access) in the R5 stage. The TD-HSDPA supports high-speed traffic with a shared channel, but its uplink mechanism causes feedback problem for scheduling. Since the base station of TD-SCDMA can estimate the location of mobile terminals precisely, it can also estimate the possible path loss. In this paper, the base station utilizes the estimated path loss for scheduling, which is related with CQI (channel quality indicator) values. The proposed mechanism can provide the TD-HSDPA scheduler with an intial CQI value for efficient transmission.

• Proceedings of the Korean Biophysical Society Conference
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• 2002.06b
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• pp.33-33
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• 2002

In our previous study (Soh and Park, 2001), we proposed that the inwardly rectifying current-voltage (I-V) relationship of small-conductance $Ca^{2＋}$-activated $K^{＋}$ channels (S $K_{Ca}$ channels) is the result of voltage-dependent blockade of $K^{＋}$ currents by intracellular divalent cations. We expressed a cloned S $K_{Ca}$ channel, rSK2, in Xenopus oocytes and further characterized the nature of the divalent cation-binding site by electrophysiological means.(omitted)

• Proceedings of the Korean Biophysical Society Conference
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• 2001.06a
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• pp.36-36
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• 2001

Small conductance $Ca^{2＋}$-activated $K^{+}$ channels (or S $K_{Ca}$ channels) are a group of $K^{＋}$-selective ion channels activated by sub-micromolar concentrations of intracellular $Ca^{2＋}$ independent of membrane voltage. We expressed a cloned S $K_{Ca}$ channel, rSK2, in Xenopus oocytes and investigated the monovalent cation selectivity of the channels. We have used site-directed mutagenesis and macro-channel recordings to identify amino acid residues influencing the ion selectivity.(omitted)d)

• Journal of Physiology & Pathology in Korean Medicine
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• v.24 no.4
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• pp.592-597
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• 2010

Cinnamomi Ramulus is one of the medicinal plants that have been used to improve various diseases caused by insufficient blood circulation. This study was performed for the investigation of vasodilation efficacy ethanol extract of Cinnamomi Ramulus (CR). CR exhibited vascular relaxation against phenylephrine (PE, $10^{-6}M$)-, KCl- and NaF-induced contraction in rat thoracic aorta. In addition, its relaxation was endothelium-independent. Treatment of potassium channel blockers such as gilbenclamide (Gli, $10^{-5}M$), tetraethylammonium (TEA, 1 mM) and 4-aminopyridine (4-AP, 0.2 mM) did not effect on the relaxation of CR. The relaxant effects were also not inhibited by pre-treatment of rat aorta with L-NAME ($10^{-4}M$), methylene blue ($10^{-5}M$), indomethacin ($10^{-5}M$), and atropine ($10^{-6}M$). However, nifedipine ($10^{-5}M$), L-type $Ca^{2+}$ channel blocker, in part attenuated the relaxation of CR ($0.2\;mg/m{\ell}$), but SK&F96365 ($3{\times}10^{-5}M$), receptor activated $Ca^{2+}$ channel blocker and 2-APB ($10^{-4}M$), store operated $Ca^{2+}$ channel blocker did not affact dilation of CR. These findings suggest that the endothelium-independent relaxation effect of CR is partly related with inhibition of $Ca^{2+}$ influx via voltage dependent $Ca^{2+}$ channel.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.9
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• pp.1001-1009
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• 2016

In LTE networks, the base station transmits control information over the physical downlink control channel (PDCCH) including scheduling grants, which are used to indicate the resources that the user equipment uses to send data to the base station. Because the size of the PDCCH message and the number of the PDCCH transmissions increase in proportion to the number of user equipments, the overhead of the PDCCH may cause serious network congestion problems in the narrowband LTE (NB-LTE) system. This paper proposes the compact PDCCH information bit allocation to reduce the size of the PDCCH message and evaluates the performance of the semi-persistent scheduling (SPS) in the NB-LTE system. The simulation results show that the SPS can significantly reduce the signaling overhead of the PDCCH and therefore increase the system utilization.

• IEIE Transactions on Smart Processing and Computing
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• v.5 no.6
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• pp.383-389
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• 2016

This paper presents a novel automatic white balance (AWB) algorithm for consumer imaging devices. While existing AWB methods require reference white patches to correct color, the proposed method performs the AWB function using only an input image in two steps: i) white point detection, and ii) color constancy gain computation. Based on the dark channel prior assumption, a white point or region can be accurately extracted, because the intensity of a sufficiently bright achromatic region is higher than that of other regions in all color channels. In order to finally correct the color, the proposed method computes color constancy gain values based on the Y component in the XYZ color space. Experimental results show that the proposed method gives better color-corrected images than recent existing methods. Moreover, the proposed method is suitable for real-time implementation, since it does not need a frame memory for iterative optimization. As a result, it can be applied to various consumer imaging devices, including mobile phone cameras, compact digital cameras, and computational cameras with coded color.