Load Balancing Algorithm Based on QoS Awareness Applied in Wireless Networks

CHEN Xiangqian,MA Shaohui,Zhao Kai 보안공학연구지원센터 2015 International Journal of Future Generation Communi Vol.8 No.4

In order to reduce business latency and packet loss rate, to improve the throughput of integration of heterogeneous wireless network, to achieve load diversification and to improve end quality of service, while there are many problems on the dropout rate of the traditional load balancing algorithm in processing throughput, delay and business, therefore, gateway load balancing algorithm is proposed in this paper. All terminals in the access network can reflect the effectiveness of the average network load level of the network, this algorithm will gain weight of the load in the network of small business terminal to switch to the network load which is light. First, it defines the heterogeneous networks and network terminal payoff function utility function, which are used to characterize the experience and network QOS terminal load situation, and then presents the specific processes of the gateway load balancing algorithm. Finally, switching decisional load balancing algorithm, proposed by Yan X, etc. is compared with simulation experiments and it shows that: the proposed gateway load balancing algorithm has strong robustness to achieve network load balancing and to achieve a balanced use of network resource.

Compressive behavior of concrete under high strain rates after freeze-thaw cycles

Xudong Chen,Chen Chen,Zhiheng Liu,Jun Lu,Xiangqian Fan 사단법인 한국계산역학회 2018 Computers and Concrete, An International Journal Vol.21 No.2

The dynamic compressive behavior of concrete after freezing and thawing tests are investigated by using the split Hopkinson pressure bar (SHPB) technique. The stress-strain curves of concrete under dynamic loading are measured and analyzed. The setting numbers of freeze-thaw cycles are 0, 25, 50, and 75 cycles. Test results show that the dynamic strength decreases and peak strain increases with the increasing of freeze-thaw cycles. Based on theWeibull distribution model, statistical damage constitutive model for dynamic stress-strain response of concrete after freeze-thaw cycles was proposed. At last, the fragmentation test of concrete subjected to dynamic loading and freeze-thaw cycles is carried out using sieving statistics. The distributions of the fragment sizes are analyzed based on fractal theory. The fractal dimensions of concrete increase with the increasing of both freeze-thaw cycle and strain rate. The relations among the fractal dimension, strain rates and freeze-thawing cycles are developed.

Ultra-Precision Diamond Turning Error Compensation via Iterative Learning from On-machine Measured Data

ZaoZao Chen,WeiWei Huang,ZhiWei Zhu,XinQuan Zhang,LiMin Zhu,XiangQian Jiang 한국정밀공학회 2023 International Journal of Precision Engineering and Vol.24 No.12

In ultra-precision diamond turning, the reduction of machining form errors can generally be achieved through on-machine measurement and compensation. However, the efficiency of conventional compensation methods is often insufficient, particularly when high form accuracy is required or when intricate surface topography and microstructures need to be machined. Consequently, this research proposes a novel machining error compensation method based on iterative learning from on-machine measured data to enhance the machining accuracy and compensation efficiency. The on-machine measurement system and cutting path generation algorithm are introduced first. Then, the compensation method via iterative learning is presented theoretically, demonstrating a higher convergence order compared to the conventional method. Finally, machining experiments involving the cutting of cosine surfaces are conducted, followed by measurements of the processed workpieces. The experimental results indicate that after four rounds of compensation using the conventional method, the peak-to-valley (PV) value of the form error is reduced to 0.1134 μm. In contrast, employing the proposed method, a similar value of 0.1156 μmis achieved after only two rounds of compensation. This highlights the significant reduction in compensation time facilitated by the proposed method. Furthermore, the measurement results verify that the proposed compensation method maintains excellent surface quality.

The Acoustic Emission Signal Recognition based on Wavelet Transform and RBF Neural Network

Shaohui Ma,Xiangqian Chen 보안공학연구지원센터 2015 International Journal of Grid and Distributed Comp Vol.8 No.2

The acoustic emission (AE) technology can be used to assess the security condition of oil storage tank without opening pot. Signal recognition is a foundation to analyze the corrosion status for oil storage tanks. Because of inadequateness of the analysis method of parameters, a new acoustic emission signal recognition method is proposed based on wavelet transform and RBF neural network. AE signal was decomposed to 6 layers by db2 wavelet and the space energy of 6-layer detail features is regarded as the vector of the AE signal characteristics. RBF neural network is designed by considering the characteristics of AE signal. The RBF neural network is trained by using the pattern known of acoustic emission signal. RBF network is used to classify experiments to corrosion, crack and condensation acoustic emission signal. The experimental results show that the recognition rate of RBF neural network reaches 93.3%, which reveals the advantage of the acoustic emission signal of neural network recognition. It has some significance of the quantitative analysis to the safety situation of oil storage tanks.

Heuristic Algorithm Based on MAXDCP and GEOCP in Grid Networ

Shaohui Ma,Xiangqian Chen 보안공학연구지원센터 2015 International Journal of Grid and Distributed Comp Vol.8 No.3

In order to solve issues of grid network as a broadband wireless access network, such as high data transmission rate and long-distance signal coverage and so on, this paper proposes two heuristic algorithms with O (m3) time complexity, based on the user neighbors’ information and location information. The algorithm will meet transferring the minimum relay deployment problem required by users into the minimum clique partition problem of adjacency graph and gives specific algorithm steps. Experimental results show that: the proposed algorithm ensures network performance and reduces network cost.

Linking UT Signals to Properties of Weakly Bonded Composites by Four-point Bending Test

Ting Zhang,Xiangqian Li,Leishan Chen 한국섬유공학회 2022 Fibers and polymers Vol.23 No.3

A new method of producing accurately controlled bond ratios in weakly bonded composites was developed toinvestigate the influence of adhesive porosity on mechanical properties of the bondline. The ultrasonic A-scan was used todetect weak bonds in adhesive joints and the ultrasonic A-scan signals of weak bonds were analyzed to link with adhesiveporosity. As well, relations of adhesive porosities to four-point bending (4PB) were established based on experimental andnumerical results. It was found that the amplitudes of amplitudes of A-scan signals of the adhesive interface areapproximately linear functions of the bond ratios, as well as the adhesive porosities. The shear strength of bondlinesdecreases linearly with the bond ratios. Based on above results, properties of weak bonds could be evaluated by the UT(Ultrasonic Test) signals, which is of great value in engineering application.

The Influence of Composite Wave Field Fluctuation Parameters Matching to Permeability of Low Permeability Reservoirs

Zengli Xiao,Junbin Chen,Xiangqian Du,Wenlong Qin 보안공학연구지원센터 2016 International Journal of Smart Home Vol.10 No.7

There are essential differences in the influence rules of the binary composite wave generated by the combination of artificial resonance wave and hydraulic impulse wave to two-phase fluid flow of low permeability reservoirs porous media oil-water. When the fluctuation parameters of binary composite wave field reaching the optimal matching, the binary composite wave will have a good synergetic effect on two-phase fluid flow of oil-water, and the improvement effect on two-phase fluid flow of low permeability reservoirs oil-water will generate resonance effect which is far more effective than unary wave field. If the fluctuation parameters of binary composite wave field are not matched well, bad synergetic effect on two-phase fluid flow of oil-water will be generated ,not only it can’t raise the improvement effect on two-phase fluid flow of oil-water, but also it will make the improvement effect below unary wave field. Even there will be an inhibition effect on fluid flow of oil-water, which reduces the displacement efficiency and the availability of low permeability reservoirs water injection’s development. By using the indoor fluctuation oil recovery simulation experiment device, the influence rules of displacement vibration wave and hydraulic impulse binary composite wave field to low permeability reservoirs oil-water single phase and two-phase fluid flow feature were studied. The influence rules of amplitude, frequency, work cycle and the other important parameters of composite wave to the permeability of oil-water single phase was intensively studied. Finally the mechanism of the synergetic effect generated by composite wave to two-phase fluid flow of low permeability reservoirs was analyzed.

Analysis of notch depth and loading rate effects on crack growth in concrete by FE and DIC

Xiangyi Zhu,Xudong Chen,Jun Lu,Xiangqian Fan 사단법인 한국계산역학회 2019 Computers and Concrete, An International Journal Vol.24 No.6

In this paper, the fracture characteristics of concrete specimens with different notch depths under three-point flexural loads are studied by finite element and fracture mechanics methods. Firstly, the concrete beams (the size is 700×100×150 mm) with different notch depths (a=30 mm, 45 mm, 60 mm and 75 mm respectively) are tested to study the influence of notch depths on the mechanical properties of concrete. Subsequently, the concrete beams with notch depth of 60 mm are loaded at different loading rates to study the influence of loading rates on the fracture characteristics, and digital image correlation (DIC) is used to monitor the strain nephogram at different loading rates. The test results show that the flexural characteristics of the beams are influenced by notch depths, and the bearing capacity and ductility of the concrete decrease with the increase of notch depths. Moreover, the peak load of concrete beam gradually increases with the increase of loading rate. Then, the fracture energy of the beams is accurately calculated by tail-modeling method and the bilinear softening constitutive model of fracture behavior is determined by using the modified fracture energy. Finally, the bilinear softening constitutive function is embedded into the finite element (FE) model for numerical simulation. Through the comparison of the test results and finite element analysis, the bilinear softening model determined by the tail-modeling method can be used to predict the fracture behavior of concrete beams under different notch depths and loading rates.

Mechanical properties of pervious concrete with recycled aggregate

Xiangyi Zhu,Xudong Chen,Nan Shen,Huaxuan Tian,Xiangqian Fan,Jun Lu 사단법인 한국계산역학회 2018 Computers and Concrete, An International Journal Vol.21 No.6

In order to research the influence of different recycled aggregate contents on the mechanical properties of pervious concrete, the experimental study and numerical simulation analysis of the mechanical properties of pervious concrete with five kinds of recycled aggregates contents (0%, 25%, 50%, 75% and 100%) are carried out in this paper. The experimental test were first performed on concrete specimens of different sizes in order to determine the influence of recycled aggregate on the compressive strength and splitting tensile strength, direct tension strength and bending strength. Then, the development of the internal cracks of pervious concrete under different working conditions is studied more intuitively by PFC3D. The experimental results show that the concrete compressive strength, tensile strength and bending strength decrease with the increase of the recycled aggregate contents. This trend of reduction is not only related to the brittleness of recycled aggregate concrete, but also to the weak viscosity of recycled aggregate and cement paste. It is found that the fracture surface of pervious concrete with recycled aggregate is smoother than that of natural aggregate pervious concrete by PFC3D, which means that the bridging effect is weakened in the stress transfer between the left and right sides of the crack. Through the analysis of the development of the internal cracks, the recycled aggregate concrete generated more cracks than the natural aggregate concrete, which means that the recycled aggregate concrete is easier to form a coalescence fracture surface and eventually break.

Expression and Regulation of Transcription Factor FoxA2 in Chronic Rhinosinusitis With and Without Nasal Polyps

Qing Luo,Jia Zhang,Hongtian Wang,Fenghong Chen,Xi Luo,Beiping Miao,Xingmei Wu,Renqiang Ma,Xiangqian Luo,Geng Xu,Jianbo Shi,Huabin Li 대한천식알레르기학회 2015 Allergy, Asthma & Immunology Research Vol.7 No.5

Purpose: Chronic rhinosinusitis (CRS) is characterized by the excessive production of mucus. However, the molecular mechanism underlying mucin overproduction in CRS with or without nasal polyps (CRSwNP and CRSsNP, respectively) is poorly understood. This study was conducted to assess the importance of the transcription factor FoxA2 in mucin production and to investigate the targeting of FoxA2 as a potential therapeutic strategy for mucus hypersecretion in CRS patients. Methods: We enrolled 15 CRSwNP patients, 15 CRSsNP patients, and 10 normal controls in this study. The expression levels of FoxA2, MUC5AC, and MUC5B in inflamed and healthy nasal tissues were examined via immunohistochemistry and quantitative reverse transcription-polymerase chain reaction, and the levels of several proinflammatory cytokines in nasal secretions were measured via FlowCytomix analysis. In addition, the expression of MUC5AC and FoxA2 was determined in polyp-derived epithelial cells and NCI-H292 cells after in vitro stimulation. Results: FoxA2 was significantly down-regulated, and MUC5AC and MUC5B were significantly up-regulated in both the CRSwNP and CRSsNP patients compared to the controls (P<0.05), and the protein level of FoxA2 was negatively associated with the IL-6 level in the CRS patients (P<0.05). IL-6 significantly increased MUC5AC expression but inhibited FoxA2 expression in vitro (P<0.05). Transfection with a FoxA2 expression plasmid significantly decreased MUC5AC promoter activity (P<0.05) and inhibited IL-6-induced MUC5AC production (P<0.05). In addition, clarithromycin significantly alleviated IL-6-induced FoxA2 suppression and decreased MUC5AC expression in vitro (P<0.05). Conclusions: Our findings suggest that FoxA2 may be considered a therapeutic target for the modulation of mucus hypersecretion in CRS patients.