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1

A combinatorial auction mechanism for time-varying multidimensional resource allocation and pricing in fog computing

Li Shiyong, Zhang Yanan, Sun Wei, Liu Jia

International Journal of Applied Mathematics and Computer Science

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2023

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Vol. 33, no. 2

327--339

EN

It is a hot topic to investigate resource allocation in fog computing. However, currently resource allocation in fog computing mostly supports only fixed resources, that is, the resource requirements of users are satisfied with a fixed amount of resources during the usage time, which may result in low utility of resource providers and even cause a waste of resources. Therefore, we establish an integer programming model for the time-varying multidimensional resource allocation problem in fog computing to maximize the utility of the fog resource pool. We also design a heuristic algorithm to approximate the solution of the model. We apply a dominant-resource-based strategy for resource allocation to improve resource utilization as well as critical value theory for resource pricing to enhance the utility of the fog resource pool. We also prove that the algorithm satisfies truthful and individual rationality. Finally, we give some numerical examples to demonstrate the performance of the algorithm. Compared with existing studies, our approach can improve resource utilization and maximize the utility of the fog resource pool.

2

Time-frequency Representation -enhanced Transfer Learning for Tool Condition Monitoring during milling of Inconel 718

Zhou Yuqing, Sun Wei, Ye Canyang, Peng Bihui, Fang Xu, Lin Canyu, Wang Gonghai, Kumar Anil, Sun Weifang

Eksploatacja i Niezawodność

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2023

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Vol. 25, no. 2

art. no. 165926

EN

Accurate tool condition monitoring (TCM) is important for the development and upgrading of the manufacturing industry. Recently, machine-learning (ML) models have been widely used in the field of TCM with many favorable results. Nevertheless, in the actual industrial scenario, only a few samples are available for model training due to the cost of experiments, which significantly affects the performance of ML models. A time-series dimension expansion and transfer learning (TL) method is developed to boost the performance of TCM for small samples. First, a time-frequency Markov transition field (TFMTF) is proposed to encode the cutting force signal in the cutting process to two-dimensional images. Then, a modified TL network is established to learn and classify tool conditions under small samples. The performance of the proposed TFMTF-TL method is demonstrated by the benchmark PHM 2010 TCM dataset. The results show the proposed method effectively obtains superior classification accuracies for small samples and outperforms other four benchmark methods.

3

Determination and application of pressure loss in long distance pipeline transportation of paste slurry based on pipe loop experiment

Sun Wei, Jiang Minggui, Fan Kai, Liu Zeng

Archives of Mining Sciences

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2022

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Vol. 67, no. 2

223--237

EN

Industrial size pipe loop tests were conducted to determine the effect of paste mass concentration, cement content, conveying pipe diameter and conveying volumetric flow rate, on the pipeline pressure loss of paste slurry. The tests were conducted to determine the pressure losses in the backfill system at a Copper Mines major ore body. Results show that the pressure loss of paste slurry increases with the increase in mass concentration, and when the mass concentration exceeds 70%, the pressure loss will increase sharply and would be an exponential function of paste mass concentration; as the cement content increases, the pressure loss would decrease at first and then increase with the maximum pressure loss at 11% cement content; the pressure loss increases with the increase in conveying the volumetric flow rate accordingly, while the growth rate of pressure loss will increase after the volumetric flow rate exceeds 50 m 3/h; the pressure loss of paste slurry decreases sharply with the increase in pipe diameter, i.e., the larger pipe diameter, the smaller pressure loss; lastly, the paste conveying parameters were determined as mass concentration of lower than 70% (pressure loss: 2.55 MPa/km), cement content of 5% to 11%, inside diameter of conveying pipe of 150 mm and the maximum allowable pipeline pressure of 6 MPa.

4

Full‑scale experimental investigation on progressive failure characteristics of shield segmental lining connected through segmental joints containing ductile‑iron joint panels

Zhou Long, Zhu Hehua, Shen Yi, Guan Linxing, Yan Zhiguo, Sun Wei, Li Yaoliang

Archives of Civil and Mechanical Engineering

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2022

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Vol. 22, no. 3

art. no. e120

EN

A full-scale experiment was conducted for a deep-buried drainage shield tunnel to be built in Shanghai, focusing on the evolution of mechanical properties and failure process of the segmental lining connected through segmental joints containing ductile-iron joint panels, during the changing process of the inner water pressure and lateral earth pressure. The test results indicate that the damage characteristics of the shield lining are the waterproof failure of the segmental and ring joints, and the concrete cracking failure in the lining. Being diferent from the shield lining without ductile-iron joint panels, the concrete cracks mainly exist around the hand holes of segmental joints. For these kinds of shield tunnel linings containing ductile-iron joint panels, local damage of concrete cracking is prone to occur around the hand holes of segmental joints because of the anchor bars of the joint panels distributed on both sides of the hand holes, and it has a signifcant efect on the lining deformation. In the design of shield linings, efective structural adjustment methods should be adopted to solve this local concrete failure problem.

5

Cassiterite recovery from a sulfide ore flotation tailing by combined gravity and flotation separations

Zhang Limin, Khoso Sultan Ahmed, Tian Mengjie, Sun Wei

Physicochemical Problems of Mineral Processing

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2021

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Vol. 57, iss. 1

206--215

EN

Cassiterite (SnO2) which is the most important Sn-containing mineral, is extensively found in large quantities in discarded tailings. The recovery of cassiterite from discarded sulfide ore flotation tailings can reduce resource wastage and environmental pollution. The gravity separation technique can recover multiple valuable minerals, such as cassiterite, whose densities considerably differ from those of their associated gangue minerals. However, its recovery efficiency rapidly decreases as the mineral particle grain size decreases. To recover the finer valuable mineral particles from gravity separation tailings, flotation separation can be used as a supplementary method. In this study, the gravity and flotation separation techniques are combined to recover cassiterite from a sulfide ore tailing. The Sn grade and recovery of the final concentrate is 31.40% and 88.05%, respectively, thus indicating a highly efficient recovery of cassiterite by using the combined gravity and flotation separation technique. This study can be an important reference for recovering cassiterite from low-Sn-grade tailings.

6

Analysis on the influence factor of low-strength wet shotcrete in frigid mining area

Sun Wei, Shengyou Zhang, Feng Xinglong, Hou Kepeng

Archives of Mining Sciences

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2020

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Vol. 65, no. 2

285--298

EN

Wet shotcrete technology is being gradually used in roadway support in frigid mining areas. Thus, problems such as low strength, fragility, and high repair rate have also emerged. This study focuses on low strength, cracking, and other problems in the wet shotcrete support of a mine. It introduced the fishbone diagram to investigate the effects of temperature, cement content, and water-cement ratio (W/C) on the strength of the shotcrete layer. The microscopic morphology of wet shotcrete based on scanning electron microscopy (SEM) is observed. Results demonstrated that temperature was the main influencing factor of wet shotcrete in frigid mining areas. When the curing temperature was lower than 10°C, the early strength of wet shotcrete dropped significantly. Temperatures above 15°C were favorable for later gain in strength. W/C was of a complementary relationship with strength development at different ages. Temperature was the essential factor that influenced the microscopic morphology of wet shotcrete. Furthermore, internal initial porosity and aggregate interface bonding strength had a direct effect on macro-mechanical properties of wet shotcrete.

7

Prestack AVO inversion for brittleness index of shale based on BI_Zoeppritz equation and NSGA II

Bi Chenchen, Wang Yanchun, Xie Wei, Sun Wei, Liu Wei

Acta Geophysica

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2020

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Vol. 68, no. 4

1067--1082

EN

As one of the evaluation characteristics of shale sweet spots, the brittleness index (BI) of shale formations is of great sig nifcance in predicting the range of sweet spots, and guiding hydraulic fracturing. Based on the three elastic parameters of P-wave velocity (VP), S-wave velocity (VS) and density obtained by conventional prestack AVO inversion, BI can be calcu lated indirectly using the Rickman formula. However, the conventional AVO inversion based on Zoeppritz approximation assumes that incident angle is small and elastic parameters change slowly, which afects the inversion accuracy of the three elastic parameters. Additionally, using these three elastic parameters to obtain BI indirectly also leads to cumulative errors of the inversion results. Therefore, we propose an inversion method based on BI_Zoeppritz equation to directly estimate VP, VS and BI. The BI_Zoeppritz equation is an exact Zoeppritz equation for BI, which is used as the forward operator for the proposed method. The multi-objective function of the inversion method is optimized by a fast nondominated sorting genetic algorithm (NSGA II). An initial model and an optimized search window are used to improve the inversion accuracy. The test results of model data and actual data reveal that this method can directly obtain the BI with high precision. In addition, the stability and noise immunity of the proposed method are verifed by the seismic data with random noise.

8

Application of a biconical dense medium cyclone to pre-treat a low-grade Pb-Zn sulfide ore

Jian Sheng, Sun Wei, Zheng Yong-xing

Physicochemical Problems of Mineral Processing

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2019

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Vol. 55, iss. 4

981--990

EN

A biconical dense medium cyclone (BDMC) was applied to reject the gangue from a low-grade Pb-Zn sulfide ore for the first time. Based on mineralogy and heavy liquid separation tests, it was found that the rejection of gangue by the BDMC prior to grinding and flotation was promising. The results revealed that the particle size clearly affected the heavy liquid separation process. The effects of several parameters, such as medium specific gravity (SG), spigot diameter, tilt angle, cone angle and medium/ore mass ratio, on the yield of floats and on the metal recoveries in the floats were examined and the optimal parameters were determined. The results showed that 51.22% of floats were obtained with a lead recovery of 7.92% and a zinc recovery of 12.50%. The extended tests were further carried out with the BDMC being capable of throughputs about 3 t/h, which verified the results obtained in the laboratory experiments. The use of this equipment to pre-treat the refractory ore is promising.

9

Utility optimization-based bandwidth allocation for elastic and inelastic services in peer-to-peer networks

Li Shiyong, Zhang Yue, Wang Yan, Sun Wei

International Journal of Applied Mathematics and Computer Science

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2019

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Vol. 29, no. 1

111--123

EN

This paper considers reasonable bandwidth allocation for multiclass services in peer-to-peer (P2P) networks, measures the satisfaction of each peer as a customer by a utility function when acquiring one service, and develops an optimization model for bandwidth allocation with the objective of utility maximization. Elastic services with concave utilities are first considered and the exact expression of optimal bandwidth allocation for each peer is deduced. In order to obtain an optimum in distributed P2P networks, we develop a gradient-based bandwidth allocation scheme and illustrate the performance with numerical examples. Then we investigate bandwidth allocation for inelastic services with sigmoidal utilities, which is a nonconvex optimization problem. In order to solve it, we analyze provider capacity provisioning for bandwidth allocation of inelastic services and modify the update rule for prices that service customers should pay. Numerical examples are finally given to illustrate that the improved scheme can also efficiently converge to the global optimum.

10

Pharmacokinetics of panasenoside in rats and tissue distribution in mice by ultra-performance liquid chromatography tandem mass spectrometry

Chen Ruijie, Lu Mengrou, Tu Xiaoting, Sun Wei, Ye Weijian, Ma Jianshe, Wen Congcong, Wang Xianqin, Geng Peiwu

Acta Chromatographica

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2019

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Vol. 31, no. 2

146--150

EN

We developed an ultra-performance liquid chromatography tandem mass spectrometry (UPLC–MS/MS) method for quantification of panasenoside pharmacokinetics in rat plasma and tissue distribution in mouse. Twelve male Sprague-Dawley rats were used for pharmacokinetics after intravenous (2 or 10 mg/kg) administration of panasenoside, six rats for each dose. Thirty mice were randomly divided into six groups (five mice for each group, one group for each time point) and received 20 mg/kg of panasenoside by intraperitoneal administration. Calibration plots were in the range of 2–2000 ng/mL for panasenoside in rat plasma and 2–3000 ng/mL in mouse tissues. The relative standard deviation (RSD) of inter-day and intra-day precision was less than 14%. The accuracy was between 89.6% and 110.0%. The AUC(0-t) was 160.8 ± 13.0 and 404.9 ± 78.0 ng/mL*h, and t1/2 of 3.2 ± 1.2 and 4.6 ± 1.7 h, CL (clearance) of 10.0 ± 2.0, and 21.4 ± 2.0 L/h/kg after intravenous administration 2 mg/kg and 10 mg/kg of panasenoside, respectively. The tissue distribution results indicated that the panasenoside diffuses rapidly and widely into major organs. The level of panasenoside was highest in mouse liver, followed by kidney, lung, and spleen. The overwhelming accumulation in liver indicated that liver was responsible for the extensive metabolism.

11

Pharmacokinetics in rat plasma and tissue distribution in mice of galangin determined by UHPLC–MS/MS

Ye Weijian, Sun Wei, Chen Ruijie, Wang Zhe, Cui Xiao, Zhang Hui, Qian Shuyi, Zheng Qi, Zhou Yangfeng, Wan Jiafeng, Xu Jiali, Wang Xianqin, Zhou Yunfang

Acta Chromatographica

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2019

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Vol. 31, no. 2

120--125

EN

Galangin (GAL), the major bioactive flavonol extracted from Alpinia officinarum Hance (Zingiberaceae), has attracted much attention due to its multiple biological activities. To develop a fast, reliable, and sensitive ultrahigh-performance liquid chromatography–tandem mass spectrometry (UHPLC–MS/MS) method for the quantification of GAL in rat plasma and mouse tissues. UHPLC–MS/MS using electrospray ionization operating in negative-ion mode was used to determinate GAL in 18 rats receiving three doses of GAL (2 and 9 mg/kg by intravenous injection, 5 mg/kg by oral administration), with six rats for each dose. Blood samples were collected at 0.0333, 0.25, 0.5, 1, 2, 4, 6 and 8 h. A total of 25 mice received 18 mg/kg GAL by intraperitoneal injection. Liver, heart, lung, spleen, brain, and kidney tissue samples were collected at 0.25, 0.5, 2, 4, and 6 h. The precision of the method was better than 12.1%, while the accuracy ranged from −4.8% to 8.1%. The results of pharmacokinetics demonstrated rapid GAL absorption (tmax of 0.25 h), fast elimination (t1/2 <1.1 h) after three different dosages, and an absolute bioavailability of ~7.6%. Tissue distribution analysis revealed abundant GAL in liver, kidney, spleen, and lung and smaller amounts in brain. The developed method proved fast (3 min), efficient, and reliable, with high selectivity for the quantitative analysis of GAL in biological samples. This is the first study to identify the target tissues of GAL, and the results may help to elucidate the mechanisms underlying its therapeutic effects in vivo.