• International Journal of Computer Science & Network Security
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• v.23 no.5
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• pp.172-178
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• 2023

In this paper, performance of autoencoder based OFDM communication systems is compared with IEEE 802.11a Wireless Lan System (Wi-Fi). The proposed autoencoder based OFDM system is composed of the following steps. First, one sub-carrier's transmitter - channel - receiver system is created by autoencoder. Then learning process of the one sub-carrier autoencoder generates constellation map. Secondly, using the plural sub-carrier autoencoder systems, parallel bundle is configured with inserting IFFT and FFT before and after the channel to configure OFDM system. Finally, the receiver part of the OFDM communication system was updated by re-learning process for adapting channel condition such as multipath channel. For performance comparison, IEEE802.11a and the proposed autoencoder based OFDM system are compared. For channel estimation, Wi-Fi uses initial long preamble to measure channel condition. but Autoencoder needs re-learning process to create an equalizer which compensate a distortion caused by the transmission channel. Therefore, this autoencoder based system has basic advantage to the Wi-Fi system. For the comparison of the system, additive random noise and 2-wave and 4-wave multipaths are assumed in the transmission path with no inter-symbol interference. A simulation was performed to compare the conventional type and the autoencoder. As a result of the simulation, the autoencoder properly generated automatic constellations with QPSK, 16QAM, and 64QAM. In the previous simulation, the received data was relearned, thus the performance was poor, but the performance improved by making the initial value of reception a random number. A function equivalent to an equalizer for multipath channels has been realized in OFDM systems. As a future task, there is not include error correction at this time, we plan to make further improvements by incorporating error correction in the future.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.1
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• pp.163-168
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• 2015

This paper analyzed the deviation of tunneling current for bottom gate voltage of sub-10 nm asymmetric double gate MOSFET. The asymmetric double gate MOSFET among multi gate MOSFET developed to reduce the short channel effects has the advantage to increase the facts to be able to control the channel current, compared with symmetric double gate MOSFET. The increase of off current is, however, inescapable if aymmetric double gate MOSFET has the channel length of sub-10 nm. The influence of tunneling current was investigated in this study as the portion of tunneling current for off current was calculated. The tunneling current was obtained by the WKB(Wentzel-Kramers-Brillouin) approximation and analytical potential distribution derived from Poisson equation. As a results, the tunneling current was greatly influenced by bottom gate voltage in sub-10 nm asymmetric double gate MOSFET. Especially it showed the great deviation for channel length, top and bottom gate oxide thickness, and channel thickness.

• Fisheries and Aquatic Sciences
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• v.27 no.9
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• pp.614-621
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• 2024

Channel catfish (Ictalurus punctatus), an introduced species in Vietnam, is widely cultured in the Northern provinces. The off-white grub disease in Channel catfish, caused by metacercariae of Dollfustrema bagarii (Digenea: Bucephalidae) lodged in internal organs, often results in heavy economic losses. Up to the present, there have been no specific guidelines for preventing and treating this disease. Here, we explore the potential treatment of infected channel catfish through the injection of Ivermectin. We evaluated the tolerance of channel catfish to the drug and determined the optimal dosage for treating off-white grubs disease. Healthy fish weighing 180-200 g received dosages of up to 3.250 mg/kg of body weight. The median lethal dose (LD₅₀) throughout a 24-hour period was 0.808 mg/kg body weight, with a confidence interval ranging from 0.583 to 1.118 mg/kg body weight. The infected fish used for treatment testing ranged in weight from 400 to 500 g. The value for the 24-hour median effective dose (ED₅₀) was 0.253 mg, and the appropriate therapeutic injection ranged from 0.300 to 0.700 mg per kg of body weight. Flowing the histopathological alterations, after the metacercariae were shriveled and died, the immune cells cleaned and eliminated them from fish.

• Journal of Advanced Marine Engineering and Technology
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• v.35 no.6
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• pp.773-778
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• 2011

The International Maritime Organization(IMO) could try to adopt more severe amendment to prevent any air pollution from various waste materials by marine incinerator. This study is to analyse the performance improvement through Ansys CFD about new invented system which has three flue-gas discharge channels and sub-ejector installed in the dischage channel in order to evacuate flue-gas well from the combustion chamber. The results showed that the discharge temperature of flue-gas was below the regulated value of IMO by the multi-channels, and the sub-ejector system installed in the discharge channel was highly effective one to improve the flue-gas discharge ability.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.20 no.1
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• pp.85-90
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• 2006

This paper presents experimental results relating to the preliminary breakdown characteristics in $SF_6/CO_2$ gas mixtures under a highly non-uniform electric field. The impulse pre-breakdown developments are investigated by the measurements of corona current and light emission images. As a result, the preliminary breakdown development mechanisms for both the positive and negative polarities were fundamentally same. The first streamer corona was initiated at the tip of needle electrode, and the leaders developed with a stepwise propagation and bridged the test gap. The pause time of leader pulses in the positive polarity was significantly shorter than that in the negative polarity. Also, the time interval between the first streamer corona onset and breakdown in the negative polarity was much longer than that in the positive polarity. The discharge channel path in the positive polarity was zigzag, and the leader channel in the negative polarity was thicker and brighter than that in the positive polarity.

• Korean Journal of Pharmacognosy
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• v.51 no.1
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• pp.41-48
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• 2020

This study was conducted to evaluate the effects of Padina arborescens and 1-O-myristoyl-2-O-oleoyl-3-O-(α-D-glucopyranosyl)-glycerol(MOGG), its active component, on the prevention of hair loss. The P. arborescens extract and MOGG inhibited the activity of 5α-reductase, which converts testosterone to dihydrotestosterone(DHT), a main cause of androgenetic alopecia. When immortalized rat vibrissa dermal papilla cells were treated with MOGG, the proliferation of dermal papilla cells significantly increased. In addition, we found that the P. arborescens extract and MOGG could open the K_ATP channel, which may contribute to increase hair growth. Furthermore, MOGG promoted PGE₂ production in HaCaT cells. The results suggest that MOGG from the P. arborescens extract has the potential to treat alopecia via 5α-reductase inhibition, the proliferation of dermal papilla, the opening of the K_ATP channel and/or increase of PGE₂ production.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.25 no.11
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• pp.862-866
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• 2012

Surface passivation of AlGaN/GaN heterojunction structure was examined through the thermal oxidation of evaporated Al. The Al-oxide passivation increased channel conductance of two dimensional electron gas (2DEG) on the AlGaN/GaN interface. The sheet resistance of 463 ohm/${\Box}$ for 2DEG channel before $Al_2O_3$ passivation was decreased to 417 ohm/${\Box}$ after passivation. The oxidation of Al induces tensile stress to the AlGaN/GaN structure and the stress seemed to enhance the sheet carrier density of the 2DEG channel. In addition, the $Al_2O_3$ films formed by thermal oxidation of Al suppressed thermal deterioration by the high temperature annealing.

• Molecules and Cells
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• v.44 no.10
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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.

• Proceedings of the IEEK Conference
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• 2003.07b
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• pp.1105-1108
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• 2003

In this paper, we have fabricated the hydrogenated n-channel polysilicon thin film transistor (TFT) with LDD structure and have analyzed the hot carrier degradation characteristics by electrical stress. We have compared the threshold voltage (Vth), sub-threshold slope (S), and trans-conductance (Gm) for devices with LDD (Lightly Doped Drain) structure and non-LDD at same active sizes. We have analyzed the hot carrier effects by the hydrogenation in devices. As a analyzed results, the threshold voltage, sub-threshold slope for n-channel poly-si TFT were increased, trans-conductance was decreased. The effects of hydrogenation in n-channel poly-si TFT with LDD structure were shown the lower variations of characteristics than devices of the non-LDD structure with nomal process.

• Journal of the Korean Institute of Telematics and Electronics C
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• v.34C no.2
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• pp.19-28
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• 1997

This paper presents the design of an SSIC chip for synchronization between main and sub pictures in the multi channel TV system (MUCTS). This chip can resolve problems in MUCTS, such as passing through and vertical jolt phenomena. In addition, this chip rpvivides compatibility for normal/doulble scan, interlace/progressive and normal (4:3)/wide (16:9) systems and has high hjorizontal and vertical resolutions (340) dots and 150 lines). In each mode there are 1 channel, 3 channel, and 4 position display functions. This MUCTS chip including three A/D coverters, a D/A converter and seven line memories was fabricated with one chip by using the $0.8\mu\textrm{m}$ CMOS technology. The application areas of this MUCTS ASIC chip include the wide TV, projection TV and te next generation TV for the DBS (direct broadcast system).