Joint base stations clustering and feedback bits allocation for multi-cell coordinated beamforming systems

Du, Pengfei,Yang, Qinghai,He, Qingsu,Kwak, Kyung Sup IET 2017 IET COMMUNICATIONS Vol.11 No.16

<P>In this study, the authors investigate the problem of maximising the mean rate in a multi-cell coordinated beamforming system considering practical delayed limited feedback and constrained backhaul. To tackle this hard problem, they first derive the analytical expression of the upper bound on the mean rate loss due to the clustered coordination and the imperfect channel feedback. Particularly, this upper bound quantitatively reveals a key tradeoff between decreasing inter-cell interference with larger base station (BS) cluster and decreasing inter-user interference with smaller BS cluster but improved channel state information accuracy. In light of this, they jointly optimise the BSs clustering and feedback bits allocation (BCFA) with the objective of minimising the upper bound on mean rate loss, which is equivalent to the problem of maximising the mean rate. Utilising the relaxation-and-rounding approach, a BSs clustering and feedback bits allocation algorithm, referred to as BCFA, is designed, which has good performance with low complexity. Finally, extensive simulation results are provided to demonstrate the advantages of the proposed algorithm.</P>

Distortion Minimization in Wireless Sensor Networks With Energy Harvesting

Pengfei Du,Qinghai Yang,Zhong Shen,Kyung Sup Kwak IEEE 2017 IEEE communications letters Vol.21 No.6

<P>In this letter, we investigate the distortion minimization problem by jointly optimizing the sleep-wake scheduling and the transmit power in energy harvesting wireless sensor networks. A mean square error minimization problem with a more efficient harvest-use-store architecture and limited available channels taken into account is formulated. To tackle this mixed-integer non-linear programming, we first transform it into a tractable convex problem through the integer relaxation. Subsequently, a low-complexity sleep-wake scheduling and power control algorithm is proposed to solve the transformed problem. Specifically, we uncover the special structure of the transformed problem and employ it to obtain the optimal sleep-wake policy and power allocation for each sensor node.</P>

Development and Testing of a 10 kV 1.5 kA Mobile DC De-Icer based on Modular Multilevel Converter with STATCOM Function

Pengfei Hu,Yiqiao Liang,Yi Du,Renming Bi,Chonglin Rao,Yang Han 전력전자학회 2018 JOURNAL OF POWER ELECTRONICS Vol.18 No.2

This paper introduces the development of a de-icer based on a full-bridge modular multilevel converter (FMMC). The FMMC can generate a wide range of DC voltages owing to its modularity, scalability, and redundancy, which makes it suitable for ice-melting applications. First, operating principles and voltage ranges are analyzed when FMMC is applied as a mobile de-icer. Second, two new startup strategies, constant modulation index and constant power startup strategies, are proposed. Third, the main control strategies of the de-icer are proposed. Fourth, a novel rated-current zero-power test scheme is proposed to simplify test conditions. Finally, a 10 kV 1.5 kA mobile MMC de-icer is designed and built, and experiments are carried out to validate the proposed startup, control strategies, and rated-current zero-power test scheme.

Operation optimization of auxiliary electric boiler system in HTR-PM nuclear power plant

Du Xingxuan,Ma Xiaolong,Liu Junfeng,Wu Shifa,Wang Pengfei 한국원자력학회 2022 Nuclear Engineering and Technology Vol.54 No.8

Electric boilers (EBs) are the backup steam source for the auxiliary steam system of high-temperature gas-cooled reactor nuclear power plants. When the plant is in normal operations, the EB is always in hot standby status. However, the current hot standby operation strategy has problems of slow response, high power consumption, and long operation time. To solve these problems, this study focuses on the optimization of hot standby operations for the EB system. First, mathematical models of an electrode immersion EB and its accompanying deaerator were established. Then, a control simulation platform of the EB system was developed in MATLAB/Simulink implementing the established mathematical models and corresponding control systems. Finally, two optimization strategies for the EB hot standby operation were proposed, followed by dynamic simulations of the EB system transient from hot standby to normal operations. The results indicate that the proposed optimization strategies can significantly speed up the transient response of the EB system from hot standby to normal operations and reduce the power consumption in hot standby operations, improving the dynamic performance and economy of the system.

Development and Testing of a 10 kV 1.5 kA Mobile DC De-Icer based on Modular Multilevel Converter with STATCOM Function

Hu, Pengfei,Liang, Yiqiao,Du, Yi,Bi, Renming,Rao, Chonglin,Han, Yang The Korean Institute of Power Electronics 2018 JOURNAL OF POWER ELECTRONICS Vol.18 No.2

This paper introduces the development of a de-icer based on a full-bridge modular multilevel converter (FMMC). The FMMC can generate a wide range of DC voltages owing to its modularity, scalability, and redundancy, which makes it suitable for ice-melting applications. First, operating principles and voltage ranges are analyzed when FMMC is applied as a mobile de-icer. Second, two new startup strategies, constant modulation index and constant power startup strategies, are proposed. Third, the main control strategies of the de-icer are proposed. Fourth, a novel rated-current zero-power test scheme is proposed to simplify test conditions. Finally, a 10 kV 1.5 kA mobile MMC de-icer is designed and built, and experiments are carried out to validate the proposed startup, control strategies, and rated-current zero-power test scheme.

ESPO Based Course-tracking Control of Ships with Input Delay

Yanbin Wu,Pengfei Gao,Rui Wu,Jialu Du 제어·로봇·시스템학회 2023 International Journal of Control, Automation, and Vol.21 No.3

Consider the course-tracking control issue of ships with the dynamic parameter uncertainties, unknown time-varying ocean environment disturbance, and input delay. This paper creates a novel ship course-tracking control solution scheme under a uniformed framework such that the ship course tracks the desired course. Therein, an extended state predictor observer (ESPO) is constructed to estimate the course and the yaw rate of ships as well as the total disturbance caused by ship dynamic parameter uncertainties and unknown time-varying environment disturbance at the future instants, and whereby eventually contributes to compensating both the input delay and the total disturbance. Theoretical analyses indicate that our developed ship course-tracking control law with ESPO achieves the uniform stability of ship course-tracking closed-loop control system. Simulation results and simulation comparisons on a frigate demonstrate the effectiveness and superiority of our developed control law for ships with input delay.

Inhibition of caspase-1-dependent apoptosis suppresses peste des petits ruminants virus replication

Lingxia Li,Shengqing Li,Shengyi Han,Pengfei Li,Guoyu Du,Jinyan Wu,Xiaoan Cao,Youjun Shang 대한수의학회 2023 Journal of Veterinary Science Vol.24 No.5

Background: Peste des petits ruminants (PPR), caused by the PPR virus (PPRV), is an acute and fatal contagious disease that mainly infects goats, sheep, and other artiodactyls. Peripheral blood mononuclear cells (PBMCs) are considered the primary innate immune cells. Objectives: PBMCs derived from goats were infected with PPRV and analyzed to detect the relationship between PPRV replication and apoptosis or the inflammatory response. Methods: Quantitative real-time polymerase chain reaction was used to identify PPRV replication and cytokines expression. Flow cytometry was conducted to detect apoptosis and the differentiation of CD4+ and CD8+ T cells after PPRV infection. Results: PPRV stimulated the differentiation of CD4+ and CD8+ T cells. In addition, PPRV induced apoptosis in goat PBMCs. Furthermore, apoptosis and the inflammatory response induced by PPRV could be suppressed by Z-VAD-FMK and Z-YVAD-FMK, respectively. Moreover, the virus titer of PPRV was attenuated by inhibiting caspase-1-dependent apoptosis and inflammation. Conclusions: This study showed that apoptosis and the inflammatory response play an essential role in PPR viral replication in vitro, providing a new mechanism related to the cell host response.

Acidification of drinking water improved tibia mass of broilers through the alterations of intestinal barrier and microbiota

Zhang Huaiyong,Guo Yujun,Wang Ziyang,Wang Yongshuai,Chen Bo,Du Pengfei,Zhang Xiangli,Huang Yanqun,Li Peng,Michiels Joris,Chen Wen 아세아·태평양축산학회 2022 Animal Bioscience Vol.35 No.6

Objective: Diet acidification supplementation is known to influence intestinal morphology, gut microbiota, and on phosphorus (P) utilization of broilers. Alterations in intestinal barrier and microbiota have been associated with systemic inflammation and thus regulating bone turnover. Hence the effect of acidifier addition to drinking water on tibia mass and the linkages between intestinal integrity and bone were studied. Methods: One-d-old male broilers were randomly assigned to normal water (control) or continuous supply of acidified water (2% the blend of 2-hydroxy-4-methylthiobutyric acid, lactic, and phosphoric acid) group with 5 replicates of 10 chicks per replicate for 42 d. Results: Acidification of drinking water improved the ash percentage and calcium content of tibia at 42 d. Broilers receiving acidified water had increased serum P concentration compared to control birds. The acidified group showed improved intestinal barrier, evidenced by increased wall thickness, villus height, the villus height to crypt depth ratio, and upregulated mucin-2 expression in ileum. Broilers receiving drinking water containing mixed organic acids had a higher proportion of Firmicutes and the ratio of Firmicutes and Bacteroidetes, as well as a lower population of Proteobacteria. Meanwhile, the addition of acidifier to drinking water resulted in declined ileal and serum proinflammatory factors level and increased immunoglobulin concentrations in serum. Concerning bone remodeling, acidifier addition was linked to a decrease in serum C-terminal cross-linked telopeptide of type I collagen and tartrate-resistant acid phosphatase reflecting bone resorption, whereas it did not apparently change serum alkaline phosphatase activity that is a bone formation marker. Conclusion: Acidified drinking water increased tibia mineral deposition of broilers, which was probably linked with higher P utilization and decreased bone resorption through improved intestinal integrity and gut microbiota and through decreased systemic inflammation. Objective: Diet acidification supplementation is known to influence intestinal morphology, gut microbiota, and on phosphorus (P) utilization of broilers. Alterations in intestinal barrier and microbiota have been associated with systemic inflammation and thus regulating bone turnover. Hence the effect of acidifier addition to drinking water on tibia mass and the linkages between intestinal integrity and bone were studied.Methods: One-d-old male broilers were randomly assigned to normal water (control) or continuous supply of acidified water (2% the blend of 2-hydroxy-4-methylthiobutyric acid, lactic, and phosphoric acid) group with 5 replicates of 10 chicks per replicate for 42 d.Results: Acidification of drinking water improved the ash percentage and calcium content of tibia at 42 d. Broilers receiving acidified water had increased serum P concentration compared to control birds. The acidified group showed improved intestinal barrier, evidenced by increased wall thickness, villus height, the villus height to crypt depth ratio, and upregulated mucin-2 expression in ileum. Broilers receiving drinking water containing mixed organic acids had a higher proportion of Firmicutes and the ratio of Firmicutes and Bacteroidetes, as well as a lower population of Proteobacteria. Meanwhile, the addition of acidifier to drinking water resulted in declined ileal and serum proinflammatory factors level and increased immunoglobulin concentrations in serum. Concerning bone remodeling, acidifier addition was linked to a decrease in serum C-terminal cross-linked telopeptide of type I collagen and tartrate-resistant acid phosphatase reflecting bone resorption, whereas it did not apparently change serum alkaline phosphatase activity that is a bone formation marker.Conclusion: Acidified drinking water increased tibia mineral deposition of broilers, which was probably linked with higher P utilization and decreased bone resorption through improved intestinal integrity and gut microbiota and through decreased systemic inflammation.