Jian Liu¹, Lei Wang¹, Changming Zhao^{2, 3, *}, Alan Yang⁴

CMC-Computers, Materials & Continua, Vol.63, No.1, pp. 119-130, 2020, DOI:10.32604/cmc.2020.06074

Abstract In this paper, we consider a three-hop relay system based on interference cancellation technique in Underlay cognitive radio (CR) network. Although underlay CR has been shown as a promising technique to better utilize the source of primary users (PUs), its secondary performance will be severely degraded. On one hand, by adapting the Underlay spectrum sharing pattern, secondary users (SUs) would observe the strict power constraints and be interfered by primary users. On the other hand, limited transmit power results in limited transmission range, which greatly degrade the secondary transmission capacity. To solve the problems above, we propose an interference cancellation… More >

Kai Liu^{1, 2}, Zheng Hou^{2, *}, Zhiyong She², Jian Guo²

CMES-Computer Modeling in Engineering & Sciences, Vol.122, No.1, pp. 131-148, 2020, DOI:10.32604/cmes.2020.08124

Abstract This paper studies the reentry attitude tracking control problem for hypersonic vehicles (HSV) equipped with reaction control systems (RCS) and aerodynamic surfaces. The attitude dynamical model of the hypersonic vehicles is established, and the simplified longitudinal and lateral dynamic models are obtained, respectively. Then, the compound control allocation strategy is provided and the model predictive controller is designed for the pitch channel. Furthermore, considering the complicated jet interaction effect of HSV during RCS is working, an improved model predictive control approach is presented by introducing the online parameter estimation of the jet interaction coefficient for dealing with the uncertainty and… More >

ANNIE JOUBERT^1*, SUMARI MARAIS¹, CHRISTINE MARITZ²

BIOCELL, Vol.33, No.1, pp. 67-70, 2009, DOI:10.32604/biocell.2009.33.067

Abstract Proteins of the B-cell lymphoma 2 family are crucial for the regulation of apoptosis. B-cell lymphoma 2-associated X is a pro-apoptotic protein, while B-cell lymphoma 2 protein opposes apoptosis. The influence of 1 μM 2-methoxyestradiol was investigated on the expression levels of these two proteins in MCF-7 cells. 2-Methoxyestradiol exposure did not influence B-cell lymphoma 2 protein expression levels after 24 h of exposure. In contrast, B-cell lymphoma 2-associated X protein levels were significantly reduced. An improved differential interference contrasting technique revealed compromised cell density and the presence of a mitotic block in exposed cells. The study proposes that the… More >

Lei Wang¹, Jian Liu^1,*, Alan Yang²

Journal of Information Hiding and Privacy Protection, Vol.1, No.3, pp. 119-133, 2019, DOI:10.32604/jihpp.2019.07296

Abstract In this paper, we study the state-dependent interference channel, where the Rayleigh channel is non-causally known at cognitive network. We propose an active secondary transmission mechanism with interference cancellation technique according to the ON-OFF status of primary network. the secondary transmission mechanism is divided into four cases according to the active state of the primary user in the two time slots. For these interference cases, numerical results are provided to show that active interference cancellation mechanism significantly reduces the secondary transmission performance in terms of secondary outage probability and energy efficiency. More >

Lingya Meng^{1, *}, Cuiwei Liu², Liping Fang², Yuxing Li², Juntao Fu³

Sound & Vibration, Vol.53, No.4, pp. 111-128, 2019, DOI:10.32604/sv.2019.03835

Abstract When acoustic method is used in leak detection for natural gas pipelines, the external interferences including operation of compressor and valve, pipeline knocking, etc., should be distinguished with acoustic leakage signals to improve the accuracy and reduce false alarms. In this paper, the technologies of extracting characteristics of acoustic signals were summarized. The acoustic leakage signals and interfering signals were measured by experiments and the characteristics of time-domain, frequency-domain and time-frequency domain were extracted. The main characteristics of time-domain are mean value, root mean square value, kurtosis, skewness and correlation function, etc. The features in frequency domain were obtained by… More >

C. K. Au¹

CMES-Computer Modeling in Engineering & Sciences, Vol.6, No.5, pp. 409-420, 2004, DOI:10.3970/cmes.2004.006.409

Abstract Tracking the flow fronts arising from a primary source in a bounded space with obstacles is a problem which often requires intensive computation. As the flow propagates through the obstacles, the flow pattern is complicated. This phenomenon is mainly due to the existence of the secondary sources which can be identified in the flow field by visibility. Comparing the flow fronts propagation and the wave equation reveals that the complexity is caused by the propagation phenomena: reflection, refraction, diffraction and interference. This paper investigates a geometric technique to combine these phenomena for computing flow fronts. More >

Weidong Fang¹, Wuxiong Zhang^1,2, Lianhai Shan^1,*, Biruk Assefa³, Wei Chen⁴

Journal of New Media, Vol.1, No.1, pp. 45-50, 2019, DOI:10.32604/jnm.2019.05786

Abstract As an effective error correction technology, the Low Density Parity Check Code (LDPC) has been researched and applied by many scholars. Meanwhile, LDPC codes have some prominent performances, which involves close to the Shannon limit, achieving a higher bit rate and a fast decoding. However, whether these excellent characteristics are suitable for the resource-constrained Wireless Sensor Network (WSN), it seems to be seldom concerned. In this article, we review the LDPC code’s structure brief.ly, and them classify and summarize the LDPC codes’ construction and decoding algorithms, finally, analyze the applications of LDPC code for WSN. We believe that our contributions… More >

Roshan Kumar^1,*, Wei Zhao¹, Vikash Singh²

Structural Durability & Health Monitoring, Vol.12, No.2, pp. 65-83, 2018, DOI: 10.3970/sdhm.2018.02329

Abstract This paper presents an evaluation of time-frequency methods for the analysis of seismic signals. Background of the present work is to describe, how the frequency content of the signal is changing in time. The theoretical basis of short time Fourier transform, Gabor transform, wavelet transform, S-transform, Wigner distribution, Wigner-Ville distribution, Pseudo Wigner-Ville distribution, Smoothed Pseudo Wigner-Ville distribution, Choi-William distribution, Born-Jordan Distribution and cone shape distribution are presented. The strengths and weaknesses of each technique are verified by applying them to a particular synthetic seismic signal and recorded real time earthquake data. More >

Yinghua Zhang^1,2, Yanfang Dong², Lei Wang¹, Jian Liu^1,*, Yunfeng Peng¹, Jim Feng³

CMC-Computers, Materials & Continua, Vol.60, No.1, pp. 379-393, 2019, DOI:10.32604/cmc.2019.05790

Abstract In this paper, we propose a downlink cognitive non-orthogonal multiple access (NOMA) network, where the secondary users (SUs) operate in underlay mode. In the network, secondary transmitter employs NOMA signaling for downlink transmission, and the primary user (PU) is interfered by the transmission from SU. The expressions for the outage probabilities are derived in closed-form for both primary and secondary users in the presence of channel estimation error. Numerical simulation results show that the channel estimation error and the inter-network interference cause degradation of the downlink outage performance. Also the power allocation and the location have a significant impact on… More >

B.J. Yang¹, K.J. Cho¹, G.M. Kim¹, H.K. Lee^1,2

CMES-Computer Modeling in Engineering & Sciences, Vol.103, No.5, pp. 343-365, 2014, DOI:10.3970/cmes.2014.103.343

Abstract The addition of carbon nanotubes (CNTs) to a matrix material is expected to lead to an increase in the effective electrical properties of nanocomposites. However, a CNT entanglement caused by the matrix viscosity and the high aspect ratio of the nanotubes often inhibits the formation of a conductive network. In the present study, the micromechanics-based model is utilized to investigate the effect of CNT agglomeration on the electrical conductivity and percolation threshold of nanocomposites. A series of parametric studies considering various shapes and curviness distributions of CNTs are carried out to examine the effects of entanglement on the electrical performance… More >