ABEP Performance of ISDF Relaying M2M Cooperative Networks

( Lingwei Xu ),( Jingjing Wang ),( Han Wang ),( T. Aaron Gulliver ) 한국인터넷정보학회 2016 KSII Transactions on Internet and Information Syst Vol.10 No.12

In this paper, the average bit error probability (ABEP) performance of the incremental-selective decode-and-forward (ISDF) relaying mobile-to-mobile (M2M) cooperative networks over N-Nakagami fading channels is investigated. The exact ABEP expressions are derived, and the power allocation problem is formulated.The derived ABEP expressions are verified by Monte Carlo simulations. The simulation results showed that the propagation parameters, such as the fading coefficient, and the power-allocation parameter, have a significant influence on the ABEP performance.

ABEP Performance of ISDF Relaying M2M Cooperative Networks

Xu, Lingwei,Wang, Jingjing,Wang, Han,Gulliver, T. Aaron Korean Society for Internet Information 2016 KSII Transactions on Internet and Information Syst Vol.10 No.12

In this paper, the average bit error probability (ABEP) performance of the incremental-selective decode-and-forward (ISDF) relaying mobile-to-mobile (M2M) cooperative networks over N-Nakagami fading channels is investigated. The exact ABEP expressions are derived, and the power allocation problem is formulated.The derived ABEP expressions are verified by Monte Carlo simulations. The simulation results showed that the propagation parameters, such as the fading coefficient, and the power-allocation parameter, have a significant influence on the ABEP performance.

End-to-End Performance Analysis of AF Relaying M2M Cooperative System

Lingwei Xu,Hao Zhang,Jingjing Wang,Wei Shi,T. Aaron Gulliver 보안공학연구지원센터 2015 International Journal of Multimedia and Ubiquitous Vol.10 No.9

In this paper, the end-to-end performance of the mobile-relay-based mobile-to-mobile (M2M) system with amplify-and-forward (AF) relaying over N-Nakagami fading channels is investigated. The exact closed-form expressions for the lower bound on average symbol error probability (ASEP) and upper bound on channel capacity are derived. Then the ASEP and channel capacity performance under different conditions is evaluated to confirm the accuracy of the analysis. Results are presented which show that the fading coefficient, the number of cascaded components, the relative geometrical gain, and the power-allocation parameter have an important influence on the ASEP and channel capacity performance.

Performance Analysis of the M2M Network over Keyhole Nakagami Fading Channels

Lingwei Xu,Hao Zhang,Tingting Lu,Zengfeng Wang,T. Aaron Gulliver 보안공학연구지원센터 2015 International Journal of u- and e- Service, Scienc Vol.8 No.7

The performance of the mobile-to-mobile (M2M) network over keyhole Nakagami fading channels is investigated in this paper. Using the method of the probability density function (PDF) of the signal-to-noise ratio (SNR), the exact and approximate closed-form average symbol error probability (ASEP) expressions are derived for pulse-amplitude modulation (PAM), phase shift keying (PSK),and frequency shift keying modulation (FSK). The exact closed-form expressions for channel capacity are also presented. Then the ASEP and channel capacity performance under different conditions is evaluated through numerical simulations to verify the analysis. The simulation results showed that the performance of the M2M network is improved with the transmitting/receiving antennas and the fading coefficient increased.

Novel Preamble Design for Channel Estimation in FBMC/OQAM Systems

( Han Wang ),( Wencai Du ),( Lingwei Xu ) 한국인터넷정보학회 2016 KSII Transactions on Internet and Information Syst Vol.10 No.8

The nonorthogonality between the real and imaginary FBMC/OQAM modulated signals complicates the channel estimation (CE) process, and conventional OFDM CE methods cannot be directly applied to FBMC/OQAM. The conventional preamble-based CE schemes in FBMC/OQAM systems are mainly based on the interference approximation method (IAM) to improve the estimation performance. In this paper, we develop a novel preamble structure to improve the CE performance. We exploit the symmetry pattern to cancel interference and take into account the interference weights in this symmetric structure. The conventional preamble and the proposed preamble are compared via simulations in the IEEE 802.22, 3GPP Vehicular A and Pedestrian A channels. Numerical simulation results demonstrate that the proposed preamble can achieve better bit error ratio (BER) and mean squared error (MSE) performance under the three channel models considered.

Large Eddy Simulation of the flow around a finite-length square cylinder with free-end slot suction

Hanfeng Wang,Lingwei Zeng,Md. Mahbub Alam,Wei Guo 한국풍공학회 2020 Wind and Structures, An International Journal (WAS Vol.30 No.5

Large Eddy Simulation (LES) is used to study the effects of steady slot suction on the aerodynamic forces of and flow around a wall-mounted finite-length square cylinder. The aspect ratio H/d of the tested cylinder is 5, where H and d are the cylinder height and width, respectively. The Reynolds number based on free-stream oncoming flow velocity U∞ and d is 2.78×104. The suction slot locates near the leading edge of the free end, with a width of 0.025d and a length of 0.9d. The suction coefficient Q (= Us/U∞) is varied as Q = 0, 1 and 3, where Us is the velocity at the entrance of the suction slot. It is found that the free-end steady slot suction can effectively suppress the aerodynamic forces of the model. The maximum reduction of aerodynamic forces occurs at Q = 1, with the time-mean drag, fluctuating drag, and fluctuating lift reduced by 3.75%, 19.08%, 40.91%, respectively. For Q = 3, all aerodynamic forces are still smaller than those for Q = 0 (uncontrolled case), but obviously higher than those for Q = 1. The involved control mechanism is successfully revealed, based on the comparison of the flow around cylinder free end and the near wake for the three tested Q values.

Failure Evolution Characteristics and Resistivity Damage Model of Expansive Clay with Filled Fissures under Uniaxial Compression

Zhiao Gao,Lingwei Kong,Zhenhua Zhou,Shuangjiao Wang 대한토목학회 2023 KSCE Journal of Civil Engineering Vol.27 No.8

The fissure in expansive soil is an important factor to control the failure and stability of expansive soil foundation, slope, and underground engineering. This study utilizes the uniaxial compression–resistivity testing system to investigate the damage evolution of expansive clay with filled fissures by evaluating the stress–strain–resistivity curves of filled fissures with inclination angles of 0o, 15o, 30o, 45o, and 60o. Within the study context, the samples were continuously photographed and observed during the test, and the local strain was analyzed using digital image correlation technology. Moreover, a mechanical damage model of fissured expansive soil was proposed based on the resistivity testing data. Generally, the test results haveshown increasing the inclination angles of fissures decreases the strength linearly and changes the stress–strain behavior from hardening to softening. The failure modes of various fissure morphologies are classified into three main types: compressive fracture failure (0o), slip-fracture coupling failure (15o and 30o), and slip failure (45o and 60o). The development characteristics of local strains with different fissure inclination angles are significantly different. Moreover, the soil’s effective conductivity and strain have shown significance when developing damage models. This study provides a reference for understanding fissured soil’s failure process and applying comprehensive resistivity testing technology in fissured soil mechanics.

Control of the VIV of a cantilevered square cylinder with free-end suction

Li Ying,Li Shiqing,Zeng Lingwei,Wang Hanfeng 한국풍공학회 2019 Wind and Structures, An International Journal (WAS Vol.29 No.1

A steady slot suction near the free-end leading edge of a finite-length square cylinder was used to control its aerodynamic forces and vortex-induced vibration (VIV). The freestream oncoming flow velocity (U∞) was from 3.8 m/s to 12.8 m/s. The width of the tested cylinder d = 40 mm and aspect ratio H/d = 5, where H was the height of the cylinder. The corresponding Reynolds number was from 10,400 to 35,000. The tested suction ratio Q, defined as the ratio of suction velocity (Us) at the slot over the oncoming flow velocity at which the strongest VIV occurs (Uv), ranged from 0 to 3. It was found that the free-end slot suction can effectively attenuate the VIV of a cantilevered square cylinder. In the experiments, the RMS value of the VIV amplitude reduced quickly with Q increasing from 0 to 1, then kept approximately constant for Q ≥ 1. The maximum reduction of the VIV occurs at Q = 1, with the vibration amplitude reduced by 92% , relative to the uncontrolled case. Moreover, the overall fluctuation lift of the finite-length square cylinder was also suppressed with the maximum reduction of 87%, which occurred at Q = 1. It was interesting to discover that the free-end shear flow was sensitive to the slot suction near the leading edge. The turbulent kinetic energy (TKE) of the flow over the free end was the highest at Q = 1, which may result in the strongest mixing between the high momentum free-end shear flow and the near wake.

Effects of Extrusion Temperature on the Properties of a 0.5 wt.% GNP/Al Composite in Porthole Die Extrusion

Shumei Lou,Yiming Li,Baojia Cheng,Lingwei Ran,Yue Wang,Leyao Xu,Ben Ma,Chungjian Su,Qingbiao Wang 대한금속·재료학회 2023 METALS AND MATERIALS International Vol.29 No.12

A 0.5 wt% GNP/Al composite was prepared by powder metallurgy and hot pressing. The numerical simulations and experimentsof porthole die extrusion were performed at 440 °C, 460 °C, 480 °C and 500 °C. The effect of extrusion temperatureon the microstructure and mechanical properties of the composites was studied. The results showed that the composite nearthe welding zone underwent dynamic recrystallization due to the large strain to form fine grains, some of which grew tocoarse grains because of the local high temperature. The extrusion temperature influenced the properties of the 0.5 wt%GNP/Al composite along both the extrusion and transverse directions. This influence is combined with synergistic effectson the recrystallization of the grain, fluidity and plasticity of the matrix, determined by the delamination, distribution andstructure of graphene and welding behavior in the welding zone. Therefore, the comprehensive mechanical properties ofthe composite reached the highest values in the extrusion direction and the transverse direction at 460 °C; the TEM imagesshowed that the graphene and aluminum matrix were in contact with each other via a small wavy transition overlapping zoneor that interaction forces caused by welding and shearing allowed the formation of a direct interface with the Al matrix. Thedeformed graphene formed a good interface with the matrix, ensuring outstanding mechanical properties in the welding zone.

Early IL-17A Prevention Rather Than Late IL-17A Neutralization Attenuates Toluene Diisocyanate-Induced Mixed Granulocytic Asthma

Chen Shuyu,Yu Li,Deng Yao,Liu Yuanyuan,Wang Lingwei,Li Difei,Yang Kai,Liu Shengming,Tao Ailin,Chen Rongchang 대한천식알레르기학회 2022 Allergy, Asthma & Immunology Research Vol.14 No.5

Purpose: Interleukin (IL)-17A plays a critical role in the pathogenesis of allergic airway inflammation. Yet, the exact roles of IL-17A in asthma are still controversial. Thus, the aim of this study was to dissect the roles of IL-17A in toluene diisocyanate (TDI)-induced mixed granulocytic asthma and to assess the effects of neutralizing antibody in different effector phases on TDI-induced asthma. Methods: IL-17A functions in allergic airway inflammation were evaluated using mice deficient in IL-17A (Il17a−/−) or IL-17A monoclonal antibody (IL-17A mab, intraperitoneally, 50 μg per mouse, 100 μg per mouse). Moreover, the effects of exogenous recombinant IL (rIL)-17A in vivo (murine rIL-17A, intranasally, 1 μg per mouse) and in vitro (human rIL-17A, 100 ng/mL) were investigated. Results: TDI-induced mixed granulocytic airway inflammation was IL-17A-dependent because airway hyperreactivity, neutrophil and eosinophil infiltration, airway smooth muscle thickness, epithelium injury, dysfunctional T helper (Th) 2 and Th17 responses, granulocytic chemokine production and mucus overproduction were more markedly reduced in the Il17a−/− mice or by IL-17A neutralization during the sensitization phase of wild-type (WT) mice. By contrast, IL-17A neutralization during the antigen-challenge phase aggravated TDI-induced eosinophils recruitment, with markedly elevated Th2 response. In line with this, instillation of rIL-17 during antigen sensitization exacerbated airway inflammation by promoting neutrophils aggregation, while rIL-17A during the antigen-challenge phase protected the mice from TDI-induced airway eosinophilia. Moreover, rIL-17A exerted distinct effects on eosinophil- or neutrophil-related signatures in vitro. Conclusions: Our data demonstrated that IL-17A was required for the initiation of TDI-induced asthma, but functioned as a negative regulator of established allergic inflammation, suggesting that early abrogation of IL-17A signaling, but not late IL-17A neutralization, may prevent the progression of TDI-induced asthma and could be used as a therapeutic strategy for severe asthmatics in clinical settings.