• 한국음향학회지
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• 제21권7호
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• pp.648-655
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• 2002

본 논문에서는 고성능 범용 DSP (Digital Signal Processor)를 이용하여 멀티미디어 통신 등에 널리 사용되고 있는 G.723.1 Annex A (G.723.1A)의 다채널 구현에 관해 기술한다. 다채널 구현을 위해서 G.723.1의 알고리듬과 ITU-T(International Telecommunication Union-Telecommunication)에서 제공된 정수 연산 C 코드의 모듈별 계산량을 분석한 후, 이를 기준으로 C코드를 최적화한다. 각 모듈의 최적화 과정은 ITU-T에서 제공되는 시험벡터를 이용한 검증과 병행한다. 최적화 된 코드의 성능을 측정한 결과, 200㎒ TMS320C62x에서 내부 메모리만을 사용하여 5.3/6.3 kbps 두 가지 전송률에 대해서 부호화기와 복화화기를 동시에 17 채널을 수용하였다. 또한 비트-호환 버전의 경우에는 고속 코드북 검색 알고리듬을 도입하여 음질을 유지하면서 22 채널을 수용하였다.

• Journal of Ginseng Research
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• 제29권4호
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• pp.167-175
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• 2005

The $Ca^{2+}-activated$ chloride channel (CLCA) was activated by ginseng total saponin (GTS) in Xenopus oocytes. The reverse transcription PCR (RT-PCR) method was performed with gene specific primers on oocytes. The gene specific primers were deduced from spleen cDNA in expressed sequence tags (EST) database showing high homology to the mouse CLCA. Full length of cDNA sequence was completed by linkage of several 5' and 3'-half cDNA fragments have been sequenced. We named the full cDNA to oCLCA transiently. The oCLCA gene encodes a protein of 911 amino acids with $48.9\%$ identity overall to that of mouse CLCA (mCLCA4). A predicted oCLCA amino acids sequence shows the molecular weight of 108 kDa and has four or more transmembrane domains, and also the one hydrophobic C­terminal domain. oCLCA gene was expressed ubiquitously in various tissues included oocytes, also interfered in oocytes by siRNA for oCLCA. Here, we suggest that oCLCA is a endogenous chloride channel gene in oocytes. We are studying for the identification of oCLCA gene and further physiological research.

• 대한전자공학회논문지SD
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• 제47권4호
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• pp.26-33
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• 2010

본 논문은 SoC 응용에 가능한 멀티 채널 용량형 터치 센서 유닛과 간단한 공통프로세스 유닛, 스위치 어레이를 포함하여 C-T 방법으로 터치 입력을 처리하는 ASIC을 제안하였다. 본 터치 센서 ASIC은 작은 전류와 칩 면적의 장점을 갖는 C-T 변환 방식에 기반 하여 설계하였으며, 최소 센싱 해상도는 한 카운터 당 41 fF이며, 외부 부품 없이 동작하기 위해 내부 발진기 및 LDO 레귤레이터, $I^2C$를 내장하였다. 본 ASIC은 0.18 um CMOS공정으로 구현되어 있으며, 1.8 V와 3.3 V 전원을 사용한다. 전체 소비 전력은 60 uA이고, 면적은 0.26 $mm^2$이다.

• Molecules and Cells
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• 제44권10호
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• pp.758-769
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• 2021

Calcium homeostasis modulator 1 (CALHM1) is a membrane protein with four transmembrane helices that form an octameric ion channel with voltage-dependent activation. There are four conserved cysteine (Cys) residues in the extracellular domain that form two intramolecular disulfide bonds. We investigated the roles of C42-C127 and C44-C161 in human CALHM1 channel biogenesis and the ionic current (I_CALHM1). Replacing Cys with Ser or Ala abolished the membrane trafficking as well as I_CALHM1. Immunoblotting analysis revealed dithiothreitol-sensitive multimeric CALHM1, which was markedly reduced in C44S and C161S, but preserved in C42S and C127S. The mixed expression of C42S and wild-type did not show a dominant-negative effect. While the heteromeric assembly of CALHM1 and CALHM3 formed active ion channels, the co-expression of C42S and CALHM3 did not produce functional channels. Despite the critical structural role of the extracellular cysteine residues, a treatment with the membrane-impermeable reducing agent tris(2-carboxyethyl) phosphine (TCEP, 2 mM) did not affect I_CALHM1 for up to 30 min. Interestingly, incubation with TCEP (2 mM) for 2-6 h reduced both I_CALHM1 and the surface expression of CALHM1 in a time-dependent manner. We propose that the intramolecular disulfide bonds are essential for folding, oligomerization, trafficking and maintenance of CALHM1 in the plasma membrane, but dispensable for the voltage-dependent activation once expressed on the plasma membrane.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제52권7호
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• pp.434-434
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• 2003

This paper proposes a new quantitative and objective image quality metric which is essential to verify the performance of block-based DCT image coding The proposed metric considers not only global distortion of coded image such as spatial frequency sensitivity and channel masking using HVS based multi-channel model, but also structural distortions caused block-based coding. The experimental results show a strong correlation between propose(B metric and subjective metric.

• Bulletin of the Korean Chemical Society
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• 제23권2호
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• pp.267-270
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• 2002

Photodissociations of o-, m-, and p-iodotoluene radical cations were investigated by using Fourier-transform ion cyclotron resonance (FT-ICR) spectrometry. Iodotoluene radical cations were prepared in an ICR cell by a photoionization charge-transfer method. The time-resolved one-photon dissociation spectra were obtained at 532 nm and the identities of $C_7H_7^+$ products were determined by examining their bimolecular reactivities toward toluene-$d_8$. The two-photon dissociation spectra were also recorded in the wavelength range 615-670 nm. The laser power dependence, the temporal variation, and the identities of $C_7H_7^+$ were examined at 640 nm. The mechanism of unimolecular dissociation of iodotoluene radical cations is elucidated: the lowest barrier rearrangement channel leads exclusively to the formation of the benzyl cation, whereas the direct C-I cleavage channel yields the tolyl cations that rearrange to both benzyl and tropylium cations with dissimilar branching ratios among o-, m-, and p-isomers. With a two-photon energy of 3.87 eV at 640 nm, the direct C-I cleavage channel results in the product branching ratio, [tropylium cation]/[benzyl cation], in descending order, 0.16 for meta >0.09 for ortho >0.05 for para.

• 한국통신학회논문지
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• 제27권1B호
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• pp.99-107
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• 2002

방송 디스크는 다수의 이동 클라이언트에게 정보를 전파하는 통신 구조이다. 방송 디스크에서 서버는 데이타베이스에 저장된 모든 데이타를 연속적으로 방송하며, 클라이언트는 방송 채널을 검사하여 자신이 원하는 데이타를 수신한다. 이런 관점에서 방송 채널은 클라이언트가 데이타를 액세스할 수 있는 디스크의 역할을 담당한다. 본 논문에서는 방송 데이타가 서버에서 변경될 경우, 클라이언트에서 실행되는 트랜잭션이 판독하는 데이타의 정확성을 보장하기 위한 캐쉬 기반의 동시성 제어 기법(Cache Conscious Concurrency Control: $C^4$) 기법을 제안한다. $C^4$ 기법은 서버로부터 동시성 제어를 위한 추가적인 정보의 방송을 최소화하며 클라이언트의 캐쉬를 효율적으로 사용함으로써 트랜잭션의 실행 시간을 단축시킬 수 있다는 장점을 갖는다.

• 한국광학회지
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• 제8권1호
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• pp.68-72
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• 1997

$^{13}$C$_{2}$H$_{2}$ 분자의 빛살 흡수선 중 분산천이 광섬유의 영분산 파장에 가까운 1549.49 nm 파장의 흡수선에 DFB-LD (distributed feedback laser diode)의 주파수를 안정화시켰다. 이 주파수 안정화된 DFB-LD와 광섬유 파브리-페로 필터의 투과 및 반사특성을 이용하여 광섬유 파브리-페로 필터의 중심주파수를 안정화시켰다. 자유분광너비(free spectral range)가 100 GHz인 안정화된 광섬유 파브리-페로 필터의 공진 조건에 파장이 다른 3개의 DFB-LD 빛살을 투과시켜 DFB-LD들을 안정화시킴으로써 주파수분할 다중을 하였다. 또한 레이저를 디더링(dithering) 방법으로 안정화시켰을 때 디더링 전류에 따른 레이저의 선폭변화는 600 MHz/mA였다.

• The Korean Journal of Physiology and Pharmacology
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• 제7권5호
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• pp.251-254
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• 2003

The present study was designed to examine whether the co-application of morphine with $Ca^{2+}$ channel antagonist $(Mn^{2+},\;verapamil)$, N-methyl-D-aspartate (NMDA) receptor antagonist (2-amino-5-phosphonopentanoic acid$[AP_5]$, $Mg^{2+}$) or protein kinase C inhibitor (H-7) causes the potentiation of morphine-induced antinociceptive action by using an in vivo electrophysiological technique. A single iontophoretic application of morphine or an antagonist alone induced weak inhibition of wide dynamic range (WDR) cell responses to iontophoretically applied NMDA and C-fiber stimulation. Although there was a little difference in the potentiating effects, the antinociceptive action of morphine was potentiated when morphine was iontophoretically applied together with $Mn^{2+}$, verapamil, $AP_5$, $Mg^{2+}$ or H-7. However, the potentiating action between morphine and each antagonist was not apparent, when the antinociceptive action evoked by morphine or the antagonist alone was too strong. These results suggest that the potentiating effect can be caused by the interaction between morphine and each antagonist in the spinal dorsal horn.

• The Korean Journal of Physiology and Pharmacology
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• 제13권5호
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• pp.361-365
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• 2009

Effects of quercetin, a kind of flavonoids, on the vasodilating actions were investigated. Among the mechanisms for quercetin-induced vasodilatation in rat aorta, the involvement with the $Ca^{2+}$ activated $K^+$ ($K_{Ca}$) channel was examined. Pretreatment with NE ($5\;{\mu}M$) or KCl (60 mM) was carried out and then, the modulation by quercetin of the constriction was examined using rat aorta ring strips (3 mm) at $36.5^{\circ}C$. Quercetin (0.1 to $100\;{\mu}M$) relaxed the NE-induced vasoconstrictions in a concentrationdependent manner. NO synthesis (NOS) inhibitor, NG-monomethyl-L-arginine acetate (L-NMMA), at $100\;{\mu}M$ reduced the quercetin ($100\;{\mu}M$)-induced vasodilatation from $97.8{\pm}3.7%$ (n=10) to $78.0{\pm}11.6%$ (n=5, p<0.05). Another NOS inhibitor, L-NG-nitro arginine methyl ester (L-NAME), at $10\;{\mu}M$ also had the similar effect. In the presence of both $100\;{\mu}M$ L-NMMA and $10\;{\mu}M$ indomethacin, the quercetin-induced vasodilatation was further attenuated by $100\;{\mu}M$ tetraethylammonium (TEA, a $K_{Ca}$ channel inhibitor). Also TEA decreased the quercetin-induced vasodilatation in endothelium-denuded rat aorta. Used other $K_{Ca}$ channel inhibitors, the quercetin-induced vasodilatation was attenuated by $0.3\;{\mu}M$ apamin (a SK channel inhibitor), but not by 30 nM charybdotoxin (a BK and IK channel inhibitor). Quercetin caused a concentration-dependent vasodilatation, due to the endotheliumdependent and -independent actions. Also quercetin contributes to the vasodilatation selectively with SK channel on smooth muscle.