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Chen, Zhenxing,Liu, Jiaheng,Li, Shuang,Kang, Seog Geun Hindawi Limited 2018 WIRELESS COMMUNICATIONS AND MOBILE COMPUTING Vol.2018 No.-
<P>Two three-dimensional (3D) 16-ary signal constellations having extended lattice structures are presented in this paper. The theoretical symbol error probabilities (SEPs) of the new constellations in additive white Gaussian noise (AWGN) and Rayleigh fading channel are derived. Computer simulation confirms that the closed-form expressions for average SEPs of the constellations in the AWGN channel are very accurate. The theoretical SEP upper bounds in the Rayleigh fading channel are very tight. Since the presented constellations have larger minimum Euclidean distance (MED) than the conventional one, error performance can be improved up to 0.9 dB in an AWGN environment. Hence, the proposed constellations and their theoretical analysis can be used as a reference for the development of a wireless communication system with 3D signal constellations.</P>
Closed-form expressions for the symbol error probability of 3-D OFDM
Zhenxing Chen,Eun Chang Choi,Seog Geun Kang IEEE 2010 IEEE communications letters Vol.14 No.2
<P>In this letter, closed-form expressions for the symbol error probability of 3-D orthogonal frequency division multiplexing in additive white Gaussian noise channel are derived. When a 3-D 4-ary constellation is used as signal mapper, we calculate the upper and the lower bound for the error probability, and also provide its approximation. Since decision boundaries of 8- ary constellation form an extended regular hexahedron, an exact symbol error probability can be computed. It is verified that the theoretical error probabilities are very close to or almost the same as simulation results.</P>
A new device for restraining rail vibration of ballastless track and its effect study
Zhenxing He,Xu Zhang,Xiaotao Wang,Hualong Zhou,Quanbao Feng,Qingchao Chen,Junxia Chen,Yanbo Bai,Runxi Zhang,Nengneng Bao 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.8
A new type of rail vibration damping device (NTRVDV), which is arranged between the bottom of the rail and track bed, is proposed in this paper. The finite element model of the rail system with the NTRVDV and tuned rail damper (TRD) was established, respectively. The impact load was applied to the finite element model, and comparison of the set of existing TRD and NTRVDV on the dynamic response of rail and rail vibration decay rate. The effect of the stiffness change of the elastic layer of the NTRVDV on the rail vibration was studied, and a hammering test verified the theoretical research results. The research results show that compared with the traditional TRD, the NTRVDV has a more obvious suppression effect on rail vibration acceleration. The rail vibration decay rate is significantly improved, especially in the low-frequency stage. With the increase of the stiffness of the elastic layer of the vibration suppression device, the vibration suppression effect of the NTRVDV on the rail is improved. The change of the elastic layer stiffness significantly impacts the rail’s vibration suppression effect in the range of 0-7 kN/mm.
Balance for relative homology with respect to semidualizing modules
Zhenxing Di,Xiaoxiang Zhang,Jianlong Chen 대한수학회 2015 대한수학회보 Vol.52 No.1
We derive in the paper the tensor product functor $-\otimes_R-$ by using proper $\mathcal {G}\mathcal {P}_C$-resolutions, where $C$ is a semidualizing module. After giving several cases in which different relative homologies agree, we use the Pontryagin duals of $\mathcal {G}_C$-projective modules to establish a balance result for such relative homology over a Cohen-Macaulay ring with a dualizing module $D$.
Reversible Data Hiding in JPEG Images Using Ordered Embedding
( Zhenxing Qian ),( Shu Dai ),( Boyang Chen ) 한국인터넷정보학회 2017 KSII Transactions on Internet and Information Syst Vol.11 No.2
This paper proposes a novel method of reversible data hiding in JPEG images. After analyzing the JPEG features, we provide a new algorithm of selecting appropriate blocks and coefficients to carry secret messages. Instead of embedding data into the histogram of all coefficients, we propose a strategy of ordered embedding to hide data by histogram shifts in several rounds. On the recipient end, secret messages can be exactly extracted, and the original JPEG image can be losslessly recovered. Experimental results show that high embedding rate can be achieved with limited distortions. Most importantly, the marked JPEG file generated by the proposed method requires less storage size than state-of-the-art works.
Zhenxing Yang,Dongjiang Pan,Jianjun Zhou,Jian Chen,Zhenchuan Sun,Haining Liu 대한토목학회 2020 KSCE Journal of Civil Engineering Vol.24 No.4
This paper conducts a simulation experiment research on cutter-head vibration characteristics by evaluating a soft-hard mixed stratum (the upper layer is silty soil, whereas the lower layer is moderately weathered granite of maximum uniaxial compressive strength (UCS) 142.0 MPa and slightly weathered granite of maximum 210.0 MPa). The ratios of hard rock and soil within the tunnel face were designed to be 1:1 and 1:2. Then, the cutter-head and stratum model were subjected to vibration analysis by reasonably deployed accelerometers. Results show that: 1) different conditions of heterogeneous strata mainly affected the acceleration amplitude and frequency distribution of cutter-head, in other words, the stronger hard rock, the larger the strength difference between the hard rock and soil within a tunnel face, the larger the vibration acceleration and the more concentrated the vibration frequency distribution; 2) the radial and circumferential vibration acceleration of the cutter-head in different positions were not largely different; however, axial accelerations were largely different. The axial vibration accelerations first increased and then decreased along the radial direction of cutter-head. Considering the difference between Multi-Mode Boring Test System and real cutter-head structure, the radius of joint between the cutter-head and the flange plate should be reasonably increased according to the ratio of hard rock in tunnel face; 3) with the increasing difference between the strength of the hard rock and soil, the circumferential and axial vibration acceleration multiplied. Thus, the soil remarkably reduces the vibration of the cutter-head. These results can provide some evidence of potential application for advancing manufacturing practice for cutter-head and disc cutter of shield machine.
BALANCE FOR RELATIVE HOMOLOGY WITH RESPECT TO SEMIDUALIZING MODULES
Di, Zhenxing,Zhang, Xiaoxiang,Chen, Jianlong Korean Mathematical Society 2015 대한수학회보 Vol.52 No.1
We derive in the paper the tensor product functor -${\otimes}_R$- by using proper $\mathcal{GP}_C$-resolutions, where C is a semidualizing module. After giving several cases in which different relative homologies agree, we use the Pontryagin duals of $\mathcal{G}_C$-projective modules to establish a balance result for such relative homology over a Cohen-Macaulay ring with a dualizing module D.
Shanbin Chen,Yangwenshan Ou,Liang Zhao,Yang Li,Zhenxing Qiao,Yanling Hao,Fazheng Ren 대한소화기 기능성질환∙운동학회 2019 Journal of Neurogastroenterology and Motility (JNM Vol.25 No.1
Background/Aims Probiotics are expected to confer benefits on patients with constipation, but how probiotics act on constipated patients with variable stool consistencies remains unclear. We investigated the effect of Lactobacillus casei strain Shirota (LcS) on constipation-related symptoms, especially stool consistency, of constipated patients. Methods Constipated patients meeting the Rome III criteria were divided into 3 groups according to the Bristol Stool Form Scale (BSFS): hard (hard stool [HS], BSFS < 3), normal (normal stool [NS], ≤ 3 BSFS ≤ 4), and soft (soft stool [SS], 4 < BSFS ≤ 5) stools. Subjects in each group consumed a probiotic beverage containing 1010 colony-forming units of LcS daily for 28 days. Results LcS intervention significantly alleviated constipation-related symptoms and increased defecation frequency in all subjects. Four weeks of LcS supplementation softened the hard stools in HS, hardened the soft stools in SS, and did not alter the ideal stool consistency in NS. The short-chain fatty acid (SCFA) concentrations were highest in SS, followed by NS and HS. LcS intervention increased the stool SCFA levels in HS but reduced or did not alter the levels in NS and SS. LcS intervention increased the Pseudobutyrivibrio and Roseburia abundances in HS and decreased the Pseudobutyrivibrio abundance in SS. Conclusions LcS supplementation improved the constipation-related symptoms in constipated subjects. Differences in baseline stool consistency could result in different anti-constipation effects of LcS intervention. LcS balanced the stool consistency—softened the HS and hardened the SS. These effects could be associated with modulation of the gut microbiota and SCFA production.