• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.301.2-301.2
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• 2014

집적회로의 밀도가 높이기 위해 단일 소자의 크기를 줄이는 과정에서 발생하는 소자의 성능 저하를 줄이기 위해 새로운 구조 및 구성 물질을 변경하는 연구가 활발하게 진행되고 있다. 기존의 평면 구조를 변형한 3차원 구조의 n-channel FinFet는 소자의 구성 물질을 바꾸지 않고도 쇼트 채널효과와 누설전류를 줄일 수 있다. 다양한 구조의 유전 물질을 응용한 n-channel FinFEET은 기존의 n-channel FinFET보다 소자의 크기를 줄일 수 있는 가능성을 제시하고 있다. FinFETs에 관한 많은 연구가 진행되어 왔지만, 유전체 물질을 이용한 n-channel FinFETs의 구조에 대한 연구는 매우 적다. 본 연구는 FinFET의fin channel 영역에 유전 물질을 삽입하여 그 영향을 분석한 연구이다. FinFET의 fin channel 영역에 유전 물질을 삽입하여 평면 구조의 MOSFET에서 fully depletion SOI 구조와 같은 동작을 하도록 만들었다. 유전 물질을 삽입한 FinFET 소자의 전기적 특성을 3차원 TCAD 시뮬레이션을 툴을 이용하여 계산하였다. 유전 물질을 삽입한 n-channel FinFET에서 전자 밀도와 측면 전계의 영향이 기존의 FinFET보다 좋은 특성을 확인하였다. 또한 유전물질을 삽입한 FinFETs은 subthershold swing, 누설전류, 소비전력을 줄여 주었다. 이러한 결과는 n-Channel FinFETs의 성능을 향상시키는데 많은 도움이 될 것이다.

• Proceedings of the IEEK Conference
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• 2009.05a
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• pp.284-286
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• 2009

In this paper, we consider a cognitive radio system operating as secondary user. It uses an empty channel that is not currently used by primary users having the license to the channel. In the previous works, secondary user looks for an empty channel by choosing any channel in order or randomly and by sensing the channel to distinguish whether primary users are using. But if primary user is fixed type, we will find an empty channel faster than the mentioned channel selecting methods by using a method considering prior information about cases that primary user used the channel, since it is possible to analogize the channel access possibility of primary user according to regular time and position. Therefore, we propose a channel searching method based on the channel list for the purpose of reducing the channel searching time and improving throughput of secondary users. Firstly, we determine a weighting value of each channel based on the history of channel activities of primary users. This value is added to current channel state buffer and we search an empty channel from channel with smallest value to one with the biggest value. Finally, we compare the performances of the proposed method with those of the sequential channel searching and the random channel searching methods in terms of the average channel searching time and the average number of transmissions of secondary user.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.2A
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• pp.174-182
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• 2008

For the UHF EPC C1 Gen2 RFID system, to overcome the performance degradation in wireless channel environments, we proposed a modified tag structure which supports channel coding and its applied methodology. The reader consistently monitors the wireless channel status and sets to use channel coding functions for tags and reader only if wireless channel is corrupted. Compared with previous tag complexity, only negligible gates are needed to implement channel coding. By simulation we showed an obvious performance improvement of the identification reliability.

• The Korean Journal of Physiology and Pharmacology
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• v.27 no.1
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• pp.85-94
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• 2023

Ion channels regulate a large number of cellular functions and their functional role in many diseases makes them potential therapeutic targets. Given their diverse distribution across multiple organs, the roles of ion channels, particularly in age-associated transcriptomic changes in specific organs, are yet to be fully revealed. Using RNA-seq data, we investigated the rat transcriptomic profiles of ion channel genes across 11 organs/tissues and 4 developmental stages in both sexes of Fischer 344 rats and identify tissue-specific and age-dependent changes in ion channel gene expression. Organ-enriched ion channel genes were identified. In particular, the brain showed higher tissue-specificity of ion channel genes, including Gabrd, Gabra6, Gabrg2, Grin2a, and Grin2b. Notably, age-dependent changes in ion channel gene expression were prominently observed in the thymus, including in Aqp1, Clcn4, Hvcn1, Itpr1, Kcng2, Kcnj11, Kcnn3, and Trpm2. Our comprehensive study of ion channel gene expression will serve as a primary resource for biological studies of aging-related diseases caused by abnormal ion channel functions.

• Journal of radiological science and technology
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• v.27 no.2
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• pp.21-27
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• 2004

This study was conducted to estimate absorbed radiation doses associated with CT examinations. We compared CT dose index between single detector CT and multi detector CT. To establish radiation dose criteria in CT examination in Korea, we measured radiation dose for CT examinations in Seoul and kyungki-do. The results obtained were as follows ; 1. Averaged CTDIW value per 100 mAs was $13.5{\pm}3.2\;mGy$, and ranged from 8.1 mGy to 19.1 mGy in head phantom, was $7.1{\pm}2.0\;mGy$, and ranged from 3.7 mGy to 10.9 mGy in body phantom. 2. CTDIW was 3.2 mGy(1.26 times) larger in multi detector CT than single detector CT in head phantom, and 2.1 mGy(1.34 times) larger in body phantom. 3. The dose was the highest in 4 channel multi detector CT, and followed 8 channel multi detector CT, 16 channel multi detector CT and single detector CT in head phantom. And the dose was the highest in 4 channel and 8 channel multi detector CT, and followed 16 channel multi detector CT and single detector CT in body phantom.

• Journal of Korea Water Resources Association
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• v.37 no.9
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• pp.781-787
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• 2004

The variation of channel bed which shows the complex hydraulic characteristics at channel junction was investigated by variation of discharge ratio and location of pier. As discharge ratio increase, the depth and width of erosion region become bigger to point of 63% of channel width in case of 1:0.5 discharge ratio. It was observed that the maximum scour depth at the point of 0.5 times of the channel width in the channel junction as 2.5 times bigger than straight channel. It means that the maximum scour depth at the channel junction is 2 times greater than by experimental formulas which are widely used in practical engineering, location of pier should be determined when it is installed in channel junction.

• The Korean Journal of Physiology and Pharmacology
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• v.7 no.1
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• pp.15-23
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• 2003

Cellular redox state is known to be perturbed during ischemia and that $Ca^{2+}$ and $K^2$ channels have been shown to have functional thiol groups. In this study, the properties of thiol redox modulation of the ATP-sensitive $K^2$ ($K_{ATP}$) channel were examined in rabbit ventricular myocytes. Rabbit ventricular myocytes were isolated using a Langendorff column for coronary perfusion and collagenase. Single-channel currents were measured in excised membrane patch configuration of patch-clamp technique. The thiol oxidizing agent 5,5'-dithio-bis-(2-nitro-benzoic acid) (DTNB) inhibited the channel activity, and the inhibitory effect of DTNB was reversed by dithiothreitol (disulfide reducing agent; DTT). DTT itself did not have any effect on the channel activity. However, in the patches excised from the metabolically compromised cells, DTT increased the channel activity. DTT had no effect on the inhibitory action by ATP, showing that thiol oxidation was not involved in the blocking mechanism of ATP. There were no statistical difference in the single channel conductance for the oxidized and reduced states of the channel. Analysis of the open and closed time distributions showed that DTNB had no effect on open and closed time distributions shorter than 4 ms. On the other hand, DTNB decreased the life time of bursts and increased the interburst interval. N-ethylmaleimide (NEM), a substance that reacts with thiol groups of cystein residues in proteins, induced irreversible closure of the channel. The thiol oxidizing agents (DTNB, NEM) inhibited of the $K_{ATP}$ channel only, when added to the cytoplasmic side. The results suggested that metabolism-induced changes in the thiol redox can also modulate $K_{ATP}$ channel activity and that a modulatory site of thiol redox may be located on the cytoplasmic side of the $K_{ATP}$ channel in rabbit ventricular myocytes.

• Journal of the Korean Data and Information Science Society
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• v.25 no.6
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• pp.1207-1219
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• 2014

In this study, 1) we compare face channel and non-face channel of life insurance company and non-life insurance company with insurance employs' suitability opinion about channel type, channel property, channel evaluation items requiring when selling insurance products, 2) we construct two social networks for life insurance companies and non-life insurance companies and find/compare two networks' properties, and then want to suggest any direction about sale channel strategy. As the result of comparing social networks of life insurance company and non-life insurance company created by insurance selling channel fit evaluation, employs of life insurance companies have more common opinion than those of non-life insurance companies and so can have more same directional channel strategy. However, property insurance companies need to manage their own channel strategy based on their own circumstance.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.16 no.8
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• pp.2648-2665
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• 2022

Device-to-device (D2D) multicast has become a promising technology to provide specific services within a small geographical region with a high data rate, low delay and low energy consumption. However, D2D multicast communications are allowed to reuse the same channels with cellular uplinks and result in mutual interference in a cell. In this paper, an intelligent channel assignment algorithm is designed in D2D underlaid cellular networks with the target of maximizing network throughput. We first model the channel assignment problem to be a throughput maximizing problem which is NP-hard. To solve the problem in a feasible way, a novel channel assignment algorithm is proposed. The key idea is to find the appropriate cellular communications and D2D multicast groups to share a channel without causing critical interference, i.e., finding a channel for a D2D multicast group which generates the least interference to network based on current channel assignment status. In order to show the efficacy and effectiveness of our proposed algorithm, a novel search algorithm is proposed to find the near-optimal solution as the baseline for comparisons. Simulation results show that the proposed algorithm improves the network throughput.

• BMB Reports
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• v.44 no.10
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• pp.635-646
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• 2011

Due to its high external and low internal concentration the $Ca^{2+}$ ion is used ubiquitously as an intracellular signaling molecule, and a great many $Ca^{2+}$-sensing proteins have evolved to receive and propagate $Ca^{2+}$ signals. Among them are ion channel proteins, whose $Ca^{2+}$ sensitivity allows internal $Ca^{2+}$ to influence the electrical activity of cell membranes and to feedback-inhibit further $Ca^{2+}$ entry into the cytoplasm. In this review I will describe what is understood about the $Ca^{2+}$ sensing mechanisms of the three best studied classes of $Ca^{2+}$-sensitive ion channels: Large-conductance $Ca^{2+}$-activated $K^+$ channels, small-conductance $Ca^{2+}$-activated $K^+$ channels, and voltage-gated $Ca^{2+}$ channels. Great strides in mechanistic understanding have be made for each of these channel types in just the past few years.