• International Journal of Computer Science & Network Security
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• 제23권6호
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• pp.27-34
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• 2023

This paper proposed an Inter-Carrier-Interference (ICI) Canceling Orthogonal Frequency Division Multiplexing (OFDM) receiver for 5G mobile system to support 500 km/h linear motor high speed terrestrial transportation service. A receiver in such high-speed train sees the transmission channel which is composed of multiple Doppler-shifted propagation paths. Then, a loss of sub-carrier orthogonality due to Doppler-spread channels causes ICI. The ICI Canceler is realized by the following three steps. First, using the Demodulation Reference Symbol (DMRS) pilot signals, it analyzes three parameters such as attenuation, relative delay, and Doppler-shift of each multi-path component. Secondly, based on the sets of three parameters, Channel Transfer Function (CTF) of sender sub-carrier number 𝒏 to receiver sub-carrier number 𝒍 is generated. In case of 𝒏≠𝒍, the CTF corresponds to ICI factor. Thirdly, since ICI factor is obtained, by applying ICI reverse operation by Multi-Tap Equalizer, ICI canceling can be realized. ICI canceling performance has been simulated assuming severe channel condition such as 500 km/h, 2 path reverse Doppler Shift for QPSK, 16QAM, 64QAM and 256QAM modulations. In particular, for modulation schemes below 16QAM, we confirmed that the difference between BER in a 2 path reverse Doppler shift environment and stationary environment at a moving speed of 500 km/h was very small when the number of taps in the multi-tap equalizer was set to 31 taps or more. We also confirmed that the BER performance in high-speed mobile communications for multi-level modulation schemes above 64QAM is dramatically improved by the use of a multi-tap equalizer.

• Nutrition Research and Practice
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• 제18권2호
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• pp.194-209
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• 2024

BACKGROUND/OBJECTIVES: High levels of plasma low-density lipoprotein (LDL) cholesterol are an important determinant of atherosclerotic lesion formation. The disruption of cholesterol efflux or reverse cholesterol transport (RCT) in peripheral tissues and macrophages may promote atherogenesis. The aim of the current study was to examine whether bioactive ellagic acid, a functional food component, improved RCT functionality and high-density lipoprotein (HDL) function in diet-induced atherogenesis of apolipoproteins E (apoE) knockout (KO) mice. MATERIALS/METHODS: Wild type mice and apoE KO mice were fed a high-cholesterol Paigen diet for 10 weeks to induce hypercholesterolemia and atherosclerosis, and concomitantly received 10 mg/kg ellagic acid via gavage. RESULTS: Supplying ellagic acid enhanced induction of apoE and ATP-binding cassette (ABC) transporter G1 in oxidized LDL-exposed macrophages, facilitating cholesterol efflux associated with RCT. Oral administration of ellagic acid to apoE KO mice fed on Paigen diet improved hypercholesterolemia with reduced atherogenic index. This compound enhanced the expression of ABC transporters in peritoneal macrophages isolated from apoE KO mice fed on Paigen diet, indicating increased cholesterol efflux. Plasma levels of cholesterol ester transport protein and phospholipid transport protein involved in RCT were elevated in mice lack of apoE gene, which was substantially reduced by supplementing ellagic acid to Paigen diet-fed mice. In addition, ellagic acid attenuated hepatic lipid accumulation in apoE KO mice, evidenced by staining of hematoxylin and eosin and oil red O. Furthermore, the supplementation of 10 mg/kg ellagic acid favorably influenced the transcriptional levels of hepatic LDL receptor and scavenger receptor-B1 in Paigen diet-fed apoE KO mice. CONCLUSION: Ellagic acid may be an athero-protective dietary compound encumbering diet-induced atherogenesis though improving the RCT functionality.

• 한국통신학회논문지
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• 제27권4B호
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• pp.345-352
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• 2002

본 논문에서는 백색잡음과 페이딩환경에서 IS-95 시스템 역방향의 성능을 평가하는데 있어 컴퓨터 수행시간을 개선할 수 있는 획기적인 방법을 제안하고 제안된 방법의 효율성은 샘플수의 형태로 입증된다. 현재 통신 시스템의 성능분석에 가장 많이 사용되는 MC(Monte Carlo) 시뮬레이션 기법은 낮은 에러율에서 많은 시뮬레이션 수행시간을 요구한다. 때문에 MC 방법은 컴퓨터 수행속도의 한계를 피할 수 없게 된다. 이러한 문제점을 해결하기 위해 제안된 방식인 센트랄 모멘트 기법을 IS-95 시스템 역방향에 적용하여 MC 방법에서 요구되는 데이터 샘플수보다 적은 수신신호의 N차 센트랄 모멘트로부터 이산 확률밀집함수를 얻을 수 있다. 연속된 누적확률분포 함수는 보간법을 통해 정확하게 되고 샘플수에서의 개선 효과가 입증된다.

• 한국통신학회논문지
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• 제21권1호
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• pp.161-174
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• 1996

CDMA 역방향 링크에서 슬롯 모드로 전송되는 프리엠블을 탐색하기 위한 최대우도 동기획득 방식의 성능을 분석한다. CDMA 복조기 출력의 통계적 특성에 기초하여 신호검출 성능을 주파수 선택성 레일라이 페이딩 채널에서 다중 $H_1$ 셀의 경우에 대해 이론적으로 분석한다. 복조기 출력으로 구성되는 판정 변수의 확률밀도 함수를 수신신호의 페이딩 특성을 고려하여 단일 및 이중 안테나 시스템의 경우에 대해 유도하고 후치 적분의 수. 페이딩 율 및 안테나 다이버시티에 따른 효과를 고려하여 성능을 분석한다.

• International Journal of Internet, Broadcasting and Communication
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• 제12권1호
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• pp.81-89
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• 2020

The purpose of this study is to investigation the effects of functional compression clothing on muscle function by comparing the iEMG response of muscle during exercise according to the wearing of taping applied functional clothing. Six men in their twenties in Chungcheongnam-do were selected for the study. Resistance exercise was performed by cross-distributing the conditions of wearing and not wearing functional clothing. Resistance exercises for iEMG measurements are biceps curl, wrist curl, reverse wrist curl, kickback and push-up. iEMG measurement muscles were the biceps brachii, triceps brachii, extensor carpi ulnaris, flexor carpi radialis. During biceps curl exercise, the iEMG of triceps brachii, biceps brachii wearing condition was lower than the non-wearing condition. During kickback exercise, the iEMG of triceps brachii, extensor carpi ulnaris wearing condition was lower than the non-wearing condition. During reverse wrist curl exercise, the iEMG of extensor carpi ulnaris wearing condition was lower than the non-wearing condition. During wrist curl exercise, the iEMG of flexsor biceps brachii, carpi radialis wearing condition was lower than the non-wearing condition. During push-up exercise, the iEMG of triceps flexsor biceps brachii, carpi radialis, brachii, biceps brachii non-wearing condition was lower than the wearing condition.

• 한국결정성장학회지
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• 제25권6호
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• pp.280-284
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• 2015

Au doped $TiO_2$ nanoparticles have been synthesized using a reverse micelle technique combined with metal alkoxide hydrolysis and condensation. Au doped $TiO_2$ was coated with glass substrate. The size of the particles and thickness of the coating can be controlled by manipulating the relative rates of the hydrolysis and condensation reaction of TTIP within the micro-emulsion. The average size of synthesized Au doped $TiO_2$ nanoparticle was about in the size range of 15 to 25 nm and the Au particles formed mainly the range of 2 to 10 nm in diameter. The effect of synthesis parameters, such as the molar ratio of water to TTIP and the molar ratio of water to surfactant, are discussed. The synthesized nanopaticles were coated on glass substrate by a spin coating process. The thickness of thin film was about 80 nm. The degradation of MB on a $TiO_2$ thin film was enhanced over 20 % efficiency by the incorporation of Au.

• 한국정밀공학회지
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• 제19권6호
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• pp.62-69
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• 2002

For improving the motion accuracy of hydrostatic table, corrective machining algorithm is proposed in this paper. The algorithm consists of three main processes. reverse analysis is performed firstly to estimate rail profile from measured linear and angular motion error, in the algorithm. For the next step, corrective machining information is decided as referring to the estimating rail profile. Finally, motion errors on correctively machined rail are analized by using motion error analysis method proposed in the previous paper. These processes can be iterated until the analized motion errors are satisfied with target accuracy. In order to verify the validity of the algorithm theoretically, motion errors by the estimated rail, after corrective machining, are compared with motion errors by true rail assumed as the measured value. Estimated motion errors show good agreement with assumed values, and it is confirmed that the algorithm is effective to acquire the corrective machining information to improve the accuracy of hydrostatic table.

• International Journal of Aeronautical and Space Sciences
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• 제17권4호
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• pp.455-466
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• 2016

Chemical-kinetic parameters of the equilibrium constants to evaluate the reverse rate coefficients in the shock layer of a blunt body and the expanding flows are derived for the temperature range from 300 K to 20,000 K. The expanded equilibrium constants for the chemical reactions of the dissociation, ionization, associative ionization, and neutral and charge exchange reactions of the atmospheric species and carbon materials are proposed in the present work. In evaluating the equilibrium constants, the inter-nuclear potential energies of the molecular species are calculated by the analytical potential function of the Hulburt-Hirschfelder model, and the parameters of the analytical model are determined from the semi-classically calculated RKR potentials. The electronic states and energies of the atoms are calculated by the electronic energy grouping model, and the rovibrational states and energies of each electronic states of the molecules are evaluated by the WKB method. The expanded equilibrium constants for 31 types of the reactions are provided for the best curve-fit functions, and the recombination reaction rate coefficients evaluated from the present equilibrium constants are compared with existing measured values.

• 한국정보통신학회논문지
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• 제7권3호
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• pp.395-402
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• 2003

CDMA 셀룰라 시스템의 용량은 간섭의 양에 따라 좌우되는 특성을 갖고 있으므로 이 간섭량을 정확히 계산해야 시스템 성능 평가를 정확히 할 수 있다. 본 논문은 CDMA 셀룰라 시스템의 역방향 타셀 간섭량을 계산하기 위한 근사식을 제시하였다. 이 근사식은 Riemann-Zeta 함수를 이용하여 임의의 전파 감쇄 지수에도 적용할 수 있는 특징이 있다. 그 효용을 살펴보기 위해 계산 결과와 시뮬레이션 결과와 비교하였다. 제안된 근사식을 이용해 계산한 시스템 용량은 시뮬레이션을 통해 얻은 용량과 근사한 결과를 얻을 수 있었다. 제안된 타셀 간섭 근사식은 복합적인 전파 환경이 고려되어야 할 계층셀 시스템에서의 간섭 및 용량 계산과 알고리즘 검증에 유용하게 사용될 수 있을 것으로 생각된다.

• BMB Reports
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• 제47권1호
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• pp.8-14
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• 2014

Telomerase plays a pivotal role in the pathology of aging and cancer by maintaining genome integrity, controlling cell proliferation, and regulating tissue homeostasis. Telomerase is essentially composed of an RNA component, Telomerase RNA or TERC, which serves as a template for telomeric DNA synthesis, and a catalytic subunit, telomerase reverse transcriptase (TERT). The canonical function of TERT is the synthesis of telomeric DNA repeats, and the maintenance of telomere length. However, accumulating evidence indicates that TERT may also have some fundamental functions that are independent of its enzymatic activity. Among these telomere-independent activities of hTERT, the role of hTERT in gene transcription has been investigated in detail. Transcriptional regulation is a fundamental process in biological systems. Several studies have shown a direct involvement of hTERT in gene transcription. This mini-review will focus on the role of hTERT in gene transcription regulation, and discuss its possible mechanisms.