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Sun Beibei Institute of Embedded Engineering of Korea 2024 대한임베디드공학회논문지 Vol.19 No.2
Mobile ad hoc networks represent self-configuring networks of mobile devices that communicate without relying on a fixed infrastructure. However, traditional routing protocols in such networks encounter challenges in selecting efficient and reliable routes due to dynamic nature of these networks caused by unpredictable mobility of nodes. This often results in a failure to meet the low-delay and low-energy consumption requirements crucial for such networks. In order to overcome such challenges, our paper introduces a novel multi-objective and adaptive routing scheme based on the Q-learning reinforcement learning algorithm. The proposed routing scheme dynamically adjusts itself based on measured network states, such as traffic congestion and mobility. The proposed approach utilizes Q-learning to select routes in a decentralized manner, considering factors like energy consumption, load balancing, and the selection of stable links. We present a formulation of the multi-objective optimization problem and discuss adaptive adjustments of the Q-learning parameters to handle the dynamic nature of the network. To speed up the learning process, our scheme incorporates informative shaped rewards, providing additional guidance to the learning agents for better solutions. Implemented on the widely-used AODV routing protocol, our proposed approaches demonstrate better performance in terms of energy efficiency and improved message delivery delay, even in highly dynamic network environments, when compared to the traditional AODV. These findings show the potential of leveraging reinforcement learning for efficient routing in ad hoc networks, making the way for future advancements in the field of mobile ad hoc networking.
Sun Tingting,Zhou Beibei,Pei Tingting,Meng Hu,Zhang Junke,Ma Fengwang,Wei Qinping 한국식물학회 2021 Journal of Plant Biology Vol.64 No.5
Phosphorus is an important macronutrient for plant growth and is acquired by plants mainly as phosphate. Phosphate fertilizer is usually used to reduce inorganic phosphate (Pi) deficiency in the soil, improve the low phosphorus and drought tolerance of plants, and promote plant growth. Phosphate transporters (PHTs) play an important role in absorbing phosphorus from the soil. MdPHT1;7 was induced by Pi deficiency and drought in roots in our previous research. In this study, we cloned MdPHT1;7 and showed its heterologous expression can complement a high-affinity Pi transporter gene in the Pi uptake-defective yeast mutant BY4743. MdPHT1;7 is a phosphorus transporter located on the cell membrane. Overexpression of MdPHT1;7 in ‘Orin’ apple and ‘Micro-Tom’ tomato enhanced Pi accumulation, low Pi tolerance and drought tolerance. We hypothesized that MdPHT1;7 can enhance Pi absorption and play an important role in improving plant resistance to low phosphorus and drought stresses.
Torque Ripple Suppression Method for BLDCM Drive Based on Four-Switch Three-Phase Inverter
Pan, Lei,Sun, Hexu,Wang, Beibei,Su, Gang,Wang, Xiuli,Peng, Guili The Korean Institute of Power Electronics 2015 JOURNAL OF POWER ELECTRONICS Vol.15 No.4
A novel inverter fault-tolerant control scheme is proposed to drive brushless DC motor. A fault-tolerant inverter and its three fault-tolerant schemes (i.e., phase A fault-tolerant, phase B fault-tolerant, and phase C fault-tolerant) are analyzed. Eight voltage vectors are summarized and a voltage vector selection table is used in the control scheme to improve the midpoint current of the split capacitors. A stator flux observer is proposed. The observer can improve flux estimation, which does not require any speed adaptation mechanism and is immune to speed estimation error. Global stability of the flux observer is guaranteed by the Lyapunov stability analysis. A novel stator resistance estimator is incorporated into the sensorless drive to compensate for the effects of stator resistance variation. DC offset effects are mitigated by introducing an integral component in the observer gains. Finally, a control system based on the control scheme is established. Simulation and experiment results show that the method is correct and feasible.
Pan, Lei,Sun, Hexu,Wang, Beibei,Dong, Yan,Gao, Rui The Korean Institute of Electrical Engineers 2014 Journal of Electrical Engineering & Technology Vol.9 No.2
On the basis of the traditional ZSI (Z-source inverter), this paper presents a ESL-${\Gamma}$-ZSI, which uses a unique ${\Gamma}$-shaped impedance network and an extended SL network for boosting its output voltage in addition to their usual voltage-buck behavior. The inverter can increase the boost factor through adjusting shoot-through duty ratio and increasing the number of inductors. Capacitor voltage stress of ESL-${\Gamma}$-ZSI is a constant when 1>D>0, and ESL-${\Gamma}$-ZSI has small inductor current stress. The working principle of ESL-${\Gamma}$-ZSI and comparison with the classical ZSI and SL- ZSI are analyzed in detail. The power loss comparison between ESL-${\Gamma}$-ZSI and Cuk converter is analyzed detailedly. Simulation and experimental results are given to demonstrate the operation features of the inverter.
Liqiang Qi,Bo Sun,Beibei Yang,Su Lu 한국유방암학회 2021 Journal of breast cancer Vol.24 No.5
Purpose Triple-negative breast cancer (TNBC) is a subtype of breast cancer. Increasing evidence supports that dysregulation of long noncoding RNAs (lncRNAs) plays a vital role in cancer progression. RNA component of mitochondrial RNA processing endoribonuclease (RMRP), a lncRNA, is characterized as a tumor-propeller in some cancers, but its mechanism in TNBC remains poorly understood. This study aimed to determine whether and how RMRP functions in TNBC. Methods Cell proliferation was determined by cell counting kit-8 (CCK-8) and colony formation assays and cell apoptosis by flow cytometry analysis and terminal deoxynucleotidyl transferase-mediated nick end labeling (TUNEL) assay. Cell migration and invasion were determined by transwell assays. RNA-binding protein immunoprecipitation (RIP), luciferase reporter, and RNA pulldown assays were implemented to assess the interaction of RMRP with other molecules in TNBC cells. Results RMRP expression was elevated in TNBC cells. RMRP knockdown repressed cell proliferation, migration, and invasion, but induced apoptosis in TNBC. In addition, RMRP was found to target microRNA-766-5p (miR-766-5p) in TNBC cells. Silencing miR-766-5p enhanced cell viability and decreased apoptosis, whereas miR-766-5p overexpression had opposite effects. Furthermore, miR-766-5p was found to bind to yes-associated protein 1 (YAP1). Moreover, miR-766-5p inhibition reversed the repressive effect of RMRP knockdown on the malignant progression of TNBC. Conclusion The present study manifested that RMRP promotes the growth, migration, and invasion of TNBC cells via the miR-766-5p/YAP1 axis. These findings provide novel perspectives for TNBC treatment.
Lei Pan,Hexu Sun,Beibei Wang,Yan Dong,Rui Gao 대한전기학회 2014 Journal of Electrical Engineering & Technology Vol.9 No.2
On the basis of the traditional ZSI (Z-source inverter), this paper presents a ESL-Γ-ZSI, which uses a unique Γ-shaped impedance network and an extended SL network for boosting its output voltage in addition to their usual voltage-buck behavior. The inverter can increase the boost factor through adjusting shoot-through duty ratio and increasing the number of inductors. Capacitor voltage stress of ESL-Γ-ZSI is a constant when 1>D>0, and ESL-Γ-ZSI has small inductor current stress. The working principle of ESL-Γ-ZSI and comparison with the classical ZSI and SL- ZSI are analyzed in detail. The power loss comparison between ESL-Γ-ZSI and Cuk converter is analyzed detailedly. Simulation and experimental results are given to demonstrate the operation features of the inverter.
( Yanyan Liu ),( Hojin Ryu ),( Beibei Ge ),( Guohui Pan ),( Lei Sun ),( Kyungseok Park ),( Kecheng Zhang ) 한국미생물 · 생명공학회 2014 Journal of microbiology and biotechnology Vol.24 No.12
Wuyiencin is produced by Streptomyces ahygroscopicus var. wuyiensis CK-15 and is widely used as an antifungal agent in agriculture. Analysis of wuyiencin biosynthetic gene clusters reveals wysR, a member of the LAL-family of transcriptional regulatory genes. WysR consists of an Nterminal PAS domain and a LuxR family C-terminal helix-turn-helix motif. However, the roles of wysR in wuyiencin biosynthesis are largely unknown. In this study, we showed that inactivation of wysR resulted in the complete loss of wuyiencin production, which could be restored by complementation with a single copy of wysR. Furthermore, we successfully increased wuyiencin production to a significantly higher level by overexpression of wysR in S. wuyiensis CK-15. Quantitative real-time RT-PCR analysis showed that WysR regulates wuyiencin biosynthesis by modulating other putative regulatory genes. Thus, WysR was identified as an activator of wuyiencin biosynthesis, and overexpression of wysR gene proved to be an effective strategy for improving wuyiencin production.
Torque Ripple Suppression Method for BLDCM Drive Based on Four-Switch Three-Phase Inverter
Lei Pan,Hexu Sun,Beibei Wang,Gang Su,Xiuli Wang,Guili Peng 전력전자학회 2015 JOURNAL OF POWER ELECTRONICS Vol.15 No.4
A novel inverter fault-tolerant control scheme is proposed to drive brushless DC motor. A fault-tolerant inverter and its three fault-tolerant schemes (i.e., phase A fault-tolerant, phase B fault-tolerant, and phase C fault-tolerant) are analyzed. Eight voltage vectors are summarized and a voltage vector selection table is used in the control scheme to improve the midpoint current of the split capacitors. A stator flux observer is proposed. The observer can improve flux estimation, which does not require any speed adaptation mechanism and is immune to speed estimation error. Global stability of the flux observer is guaranteed by the Lyapunov stability analysis. A novel stator resistance estimator is incorporated into the sensorless drive to compensate for the effects of stator resistance variation. DC offset effects are mitigated by introducing an integral component in the observer gains. Finally, a control system based on the control scheme is established. Simulation and experiment results show that the method is correct and feasible.