• Title, Summary, Keyword: HCN

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The Fault Tolerance of Interconnection Network HCN(n, n) and Embedding between HCN(n, n) and HFN(n, n) (상호연결망 HCN(n, n)의 고장허용도 및 HCN(n, n)과 HFN(n, n) 사이의 임베딩)

  • Lee, Hyeong-Ok;Kim, Jong-Seok
    • The KIPS Transactions:PartA
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    • v.9A no.3
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    • pp.333-340
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    • 2002
  • Embedding is a mapping an interconnection network G to another interconnection network H. If a network G can be embedded to another network H, algorithms developed on G can be simulated on H. In this paper, we first propose a method to embed between Hierarchical Cubic Network HCN(n, n) and Hierarchical Folded-hypercube Network HFN(n, n). HCN(n, n) and HFN(n, n) are graph topologies having desirable properties of hypercube while improving the network cost, defined as degree${\times}$diameter, of Hypercube. We prove that HCN(n, n) can be embedded into HFN(n, n) with dilation 3 and congestion 2, and the average dilation is less than 2. HFN(n, n) can be embedded into HCN(n, n) with dilation 0 (n), but the average dilation is less than 2. Finally, we analyze the fault tolerance of HCN(n, n) and prove that HCN(n, n) is maximally fault tolerant.

Distinct Regional and Cellular Localization of Hyperpolarization-activated Cyclic Nucleotide-gated Channel 1 in Cerebellar Cortex of Rat

  • Kwon, Young-Joon;Kim, Tae-Sung
    • Journal of Korean Neurosurgical Society
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    • v.42 no.3
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    • pp.205-210
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    • 2007
  • Objective : Hyperpolarization-activated cyclic nucleotide-gated (HCN) channels mediate the hyperpolarization-activated currents (Ih) that participate in regulating neuronal membrane potential and contribute critically to pacemaker activity, promoting synchronization of neuronal networks. However, distinct regional and cellular localization of HCN channels in the brain have not been precisely defined. Aim of this study was to verify the precise cellular location of HCN1 channels in rat cerebellum to better understand the physiological role these channels play in synaptic transmission between CNS neurons. Methods : HCN1 expression in rat brain was analyzed using immunohistochemistry and electron-microscopic observations. Postsynaptic density-95 (PSD-95), otherwise known as locating and clustering protein, was also examined to clarify its role in the subcellular location of HCN1 channels. In addition, to presume the binding of HCN1 channels with PSD-95, putative binding motifs in these channels were investigated using software-searching method. Results : HCN1 channels were locally distributed at the presynaptic terminal of basket cell and exactly corresponded with the location of PSD-95. Moreover, nine putative SH3 domain of PSD-95 binding motifs were discovered in HCN1 channels from motif analysis. Conclusion : Distinct localization of HCN1 channels in rat cerebellum is possible, especially when analyzed in conjunction with the SH3 domain of PSD-95. Considering that HCN1 channels contribute to spontaneous rhythmic action potentials, it is suggested that HCN1 channels located at the presynaptic terminal of neurons may play an important role in synaptic plasticity.

Presynatic Expression of HCN Channel Subunits in Cerebellar Basket Cells

  • Yi, Jee-Hyun;Park, Kyung-Joon;Kang, Shin-Jung;Shin, Ki-Soon
    • Animal cells and systems
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    • v.11 no.2
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    • pp.199-204
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    • 2007
  • HCN (hyperpolarization-activated cyclic nucleotide-gated) channels, whose gene family consists of four subunits (HCN1-4), mediate depolarizing cation currents and contribute to controlling neuronal excitability. In the present study, immunohistochemical and electrophysiological approaches were used to elucidate the role of HCN channels in the cerebellum. Immunohistochemical labeling for HCN1 and HCN2 channels revealed localized expression of both channels at pinceau, the specialized structure of presynaptic axon terminals of basket cells. To determine the functional role of the presynaptic HCN channels, spontaneous inhibitory postsynaptic currents (IPSCs) were recorded from Purkinje cells, the main synaptic targets of basket cells in the cerebellum. While activation of HCN channels by 8-bromo-cAMP increased amplitude of spontaneous IPSCs, blockade of the activated HCN channels by subsequent ZD7288 application reduced the amplitude of spontaneous IPSCs to the level far below the control. Our results imply that modulation of HCN1 and HCN2 channels in presynaptic terminals of basket cells regulates neurotransmitter release, thereby controlling the excitability of Purkinje cells.

Alterations in hyperpolarization-activated cyclic nucleotide-gated cation channel (HCN) expression in the hippocampus following pilocarpine-induced status epilepticus

  • Oh, Yun-Jung;Na, Jongju;Jeong, Ji-Heon;Park, Dae-Kyoon;Park, Kyung-Ho;Ko, Jeong-Sik;Kim, Duk-Soo
    • BMB Reports
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    • v.45 no.11
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    • pp.635-640
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    • 2012
  • To understand the effects of HCN as potential mediators in the pathogenesis of epilepsy that evoke long-term impaired excitability; the present study was designed to elucidate whether the alterations of HCN expression induced by status epilepticus (SE) is responsible for epileptogenesis. Although HCN1 immunoreactivity was observed in the hippocampus, its immunoreactivities were enhanced at 12 hrs following SE. Although, HCN1 immunoreactivities were reduced in all the hippocampi at 2 weeks, a re-increase in the expression at 2-3 months following SE was observed. In contrast to HCN1, HCN 4 expressions were un-changed, although HCN2 immunoreactive neurons exhibited some changes following SE. Taken together, our findings suggest that altered expressions of HCN1 following SE may be mainly involved in the imbalances of neurotransmissions to hippocampal circuits; thus, it is proposed that HCN1 may play an important role in the epileptogenic period as a compensatory response.

Analysis the Node Disjoint Parallel Path Algorithm of HCN(n,n) (HCN(n,n)의 노드 중복 없는 병렬 경로 알고리즘)

  • 이형옥;조정호;정희창
    • Proceedings of the Korean Information Science Society Conference
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    • pp.718-720
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    • 2001
  • 본 논문에서는 하이퍼큐브보다 망 비용이 개선된 상호연결망 HCN(n,n)의 임의의 두 노드간에 노드중복하지 않는 n+1개의 병렬경로를 구성하는 방법을 제시하고, 그 결과를 통하여 HCN(n,n)의 고장지름이 dia(HCN(n,n))+4 이하임을 보인다. 이러한 병렬경로는 노드간에 메시지를 전송하는 시간을 줄일 수 있으며, HCN(n,n)의 노드 몇 개가 고장이 발생해도 통신지연시간이 발생하지 않음을 의미한다.

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Embedding Algorithm between [ 22n-k×2k] Torus and HFN(n,n), HCN(n,n) ([ 22n-k×2k] 토러스와 HFN(n,n), HCN(n,n) 사이의 임베딩 알고리즘)

  • Kim, Jong-Seok;Kang, Min-Sik
    • The KIPS Transactions:PartA
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    • v.14A no.6
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    • pp.327-332
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    • 2007
  • In this paper, we will analysis embedding between $2^{2n-k}{\times}2^k$ torus and interconnection networks HFN(n,n), HCN(n,n). First, we will prove that $2^{2n-k}{\times}2^k$ torus can be embedded into HFN(n,n) with dilation 3, congestion 4 and the average dilation is less than 2. And we will show that $2^{2n-k}{\times}2^k$ torus can be embedded into HCN(n,n) with dilation 3 and the average dilation is less than 2. Also, we will prove that interconnection networks HFN(n,n) and HCN(n,n) can be embedded into $2^{2n-k}{\times}2^k$ torus with dilation O(n). These results mean so many developed algorithms in torus can be used efficiently in HFN(n,n) and HCN(n,n).

Embedding Algorithms Hypercube, HCN, and HFN into HFCube Interconnection Networks (상호연결망 HFCube와 하이퍼큐브, HCN, HFN 사이의 임베딩 알고리즘)

  • Kim, Jong-Seok;Lee, Hyeong-Ok
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.18 no.6
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    • pp.1361-1368
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    • 2014
  • In this paper, we analyze emddings among HFCube(n,n), HCN(n,n), HFN(n,n) with lower network cost than that of Hypercube. The results are as follows. We propose that $Q_{2n}$ can be embedded into HFCube(n,n) with dilation 5, congestion 2. HCN(n,n) and HFN(n,n) are subgraphs of HFCube(n,n). HFCube(n,n) can be embedded into HFN(n,n) with dilation 3. HFCube(n,n) can be embedded into HCN(n,n) with dilation O(n). The results will be helpful to analyze several efficient properties in each interconnection network.

Abundances of HCN and HNC in the Red MSX Sources

  • Choi, Yun-Hee;Lee, Jeong-Eun;Kim, Kee-Tae
    • The Bulletin of The Korean Astronomical Society
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    • v.35 no.1
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    • pp.60.2-60.2
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    • 2010
  • We have studied the abundance ratio of HNC and HCN toward the Red MSX Sources (RMS) using HCN (J=1-0), HNC (J=1-0), $H^{13}CN$ (J=1-0), $HN^{13}C$ (J=1-0),and $N_2H^+$ (J=1-0) lines observed with the Mopra 22 m radio telescope. The RMS are massive young stellar objects identified by the MSX satellite data combined with the 2MASS data. HCN and HNC (a geometrical isomer of HCN) are among the most basic interstellar molecules. According to our analysis, the column density of HCN is found to be correlated with that of HNC. Additionally, the [HNC]/[HCN] abundance ratio is sensitive to the core temperature because HNC is depleted in high temperature regions. This result is consistent with the previous results seen in low mass starless or protostellar cores.

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OBSERVATIONS OF THE J=1-0 TRANSITION LINE OF HCN IN COMET HALE-BOPP (헤일밥 혜성의 HCN(J=1-0) 천이선 관측)

  • KIM BONG GYE;KIM HYO RYUNG;CHO SE HYUNG;KIM SANG JOON
    • Publications of The Korean Astronomical Society
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    • v.13 no.1
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    • pp.129-134
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    • 1998
  • Observations of the J=1-0 transition line of HCN were made at the center of Comet C/1995 O1 (Hale-Bopp) from November, 1996 to April, 1997 with the 14-m radio telescope at the TRAO (Taeduk Radio Astronomical Observatory). From the obtained data, an HCN production rate at each observed date was derived. The rapid variation of the HCN production rate near the perihelion was detected, and it is thought to be caused by jet(s) from the nucleus. The correlation between the visual magnitude and the HCN production rate is found to be $Q_{HCN}=27.03-0.11(m_v-5log{\Delta})$.

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Property Analysis for Parallel Processing and Hamiltonian Cycles of Hierarchical Cubic Network (계층적 하이퍼큐브의 해밀튼이안 성질과 병렬처리를 위한 성질 분석)

  • 김종석;이형옥;허영남
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • pp.412-418
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    • 2000
  • In this paper, we will propose that HCN(n,n) gets Hamiltonian Cycles and analyze embedding among HCN(n,n) and UFN(n,n), and HFN(n,n) and In-hypercube. Further, we will prove that HCN(n,n) can be embedded into HFN(n,n) with dilation 3 and the cost for HFN(n,n) to be embedded into HCN(n,n) will be O(n), and HW(n,n) can be embedded into 2n-hypercube with dilation 3 and the cost for In-hypercube to be embedded into HFN(n,n) will be O(n).

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