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Qingxian Jia,Lina Wu,Huayi Li 제어·로봇·시스템학회 2021 International Journal of Control, Automation, and Vol.19 No.2
This paper addresses the problem of robust actuator fault reconstruction for Takagi-Sugeno (T-S) fuzzy systems subjects to actuator faults, unknown inputs and time-varying delays via a Fuzzy Synthesized Learning and Luenberger Observer (FSL2O). Through a coordinate transformation, the original T-S fuzzy system is decomposed into two subsystems: subsystem-1 effected by actuator faults and subsystem-2 effected by unknown inputs. In the presented FSL2O methodology, a Reduced-Order Fuzzy Learning Observer (ROFLO) is explored for the subsystem1 to reconstruct actuator faults accurately while a Reduced-Order Fuzzy State (Luenberger) Observer (ROFSO) is designed for the subsystem-2 based on the H∞ control technique such that it has strong robustness against the unknown inputs. The synthesized design of the ROFLO and the ROFSO is formulated in a unified manner in terms of Linear Matrix Inequalities (LMIs) that can be conveniently solved using LMI optimization technique. In addition, as a comparison, a full-order FLO is suggested for robust actuator fault reconstruction. Finally, a numerical exampleand simulation are provided to demonstrate the effectiveness of the proposed approaches.
TD-DMAC: A MAC Scheme in Ad Hoc Networks Using Directional Antenna
Qingxian Pu,S. Shin,Y. Choi,S. Kaewkuekool,S. Kongswan,W. Hwang 한국멀티미디어학회 2008 한국멀티미디어학회 국제학술대회 Vol.2008 No.-
Using directional antenna in ad hoc networks can significantly improve spatial reuse and transmission range. However, it will cause some serious problem, such as the deafness problem, which impact on the network performance. This paper proposes a new MAC protocol, named Transmission Delay DMAC (TD-DMAC) to overcome the deafness problem. Simulation results show that TD-DMAC alleviates the deafness problem and greatly improves network performance.
Qingxian Jia,Huayi Li,Yingchun Zhang,Xueqin Chen 제어·로봇·시스템학회 2015 International Journal of Control, Automation, and Vol.13 No.2
This paper addresses the problem of observer-based sensor fault reconstruction for discrete-time systems subject to external disturbances via a descriptor system approach. First, an augmented descriptor system is formulated by letting the sensor fault term be an auxiliary state vector; then a discrete-time descriptor state observer is constructed to achieve concurrent reconstructions of original system states and sensor faults. Sufficient and necessary conditions for the asymptotic stability of the proposed observer are explicitly provided. To broaden its application scope, less restrictive existence conditions are further discussed. Further, sufficient conditions for the robust stability of the proposed observer are formulated in terms of linear matrix inequalities (LMIs) that can be conveniently solved using LMI optimization techniques. After that, an extension of the proposed linear approach to discrete-time nonlinear systems with Lipschitz constraint is investigated. At last, two illustrative examples are given to verify the effectiveness of the proposed techniques.
Li Qingxian,Wen Yinxian,Wang Linlong,Chen Biao,Chen Jun,Wang Hui,Chen Liaobin 생화학분자생물학회 2021 Experimental and molecular medicine Vol.53 No.-
Osteoarthritis (OA) is significantly associated with diabetes, but how hyperglycemia induces or aggravates OA has not been shown. The synovium plays a critical role in cartilage metabolism and substance exchange. Herein, we intended to investigate whether and how hyperglycemia affects the occurrence and progression of OA by influencing the synovium. In patients with knee OA and diabetes (DM OA), we found a more severe inflammatory response, higher endoplasmic reticulum stress (ERS) levels, and more advanced glycosylation end products (AGEs) accumulation in the synovium than in patients without diabetes. Subsequently, we found similar results in the DM OA group in a rat model. In the in vitro cocultivation system, high glucose-stimulated AGEs accumulation, ERS, and inflammation in rat fibroblast-like synoviocytes (FLSs), which resulted in chondrocyte degeneration due to inflammatory factors from FLSs. Furthermore, in the synovium of the DM OA group and FLSs treated with high glucose, the expression of glucose transporter 1 (GLUT1) and its regulatory factor hypoxia-inducible factor (HIF)-1α was increased significantly. Inhibitors of HIF-1α, GLUT1 or AGEs receptors attenuated the effect of high glucose on chondrocyte degradation in the FLS-chondrocyte coculture system. In summary, we demonstrated that hyperglycemia caused AGEs accumulation in FLSs via the HIF-1α-GLUT1 pathway, which increases the release of inflammatory factors from FLSs, subsequently inducing chondrocyte degradation and promoting OA progression.
Interference Aware Power Control MAC Protocol in an Ad Hoc Network for a Directional Antenna
Pu Qingxian,Won-Joo Hwang 한국멀티미디어학회 2009 한국멀티미디어학회 학술발표논문집 Vol.2009 No.1
Directional antennas have been used in ad hoc networks, significantly improving the spatial reuse of the networks. However, the extended transmission range causes collisions at the receivers of neighbors, which prevents full exploitation of the potential of the directional antenna. In this paper, we propose a new power control MAC protocol for a directional antenna. For this protocol, we propose a method to detect a set of interference nodes in the neighbors of a receiver. We then use a power control algorithm to calculate the minimum transmission power and send data. Simulation results demonstrate that this protocol increases the network performance and reduces energy consumption.
A MAC Protocol for Deafness Prevention in Ad Hoc Networks Using Directional Antenna
Pu Qingxian,Won-Joo Hwang 한국멀티미디어학회 2008 한국멀티미디어학회 학술발표논문집 Vol.2008 No.1
Using directional antennal in wireless ad hoc networks can significantly improve spatial reuse and the transmission range. However, it will cause some serious problem, such as the deafness problem, which impact on the performance of network. Briefly, deafness is caused when a transmitter fails to communicate to its intended receiver, because the receiver’ s antenna is oriented in a different direction. This paper proposes a new MAC protocol, namely TR-DMAC (Transmission Rejection DMAC) to overcome the deafness problem. The Transmission Rejection (TR) packet is transmitted by transmitter and receiver to notify the ongoing communication to neighbor nodes.
Adaptive Power Control for MAC Protocol in Ad Hoc Network with Directional Antennas
Pu Qingxian,Won-Joo Hwang 한국멀티미디어학회 2008 한국멀티미디어학회 학술발표논문집 Vol.2008 No.2
Directional antenna has been used in ad hoc networks in place of traditional omni-directional antennas. It can be significantly improved the spatial reuse of ad hoc networks, leading to higher network throughput and reducing the transmission power during a directional transmission. In order to maximize the energy saving, we propose a power control scheme that maintains a minimum transmission power level for effective transmission of packets using directional antennas.
A Media Access Control for Spatial Reuse in Wireless Ad hoc Networks
푸칭씨안,황원주,Qingxian, Pu,Hwang, Won-Joo The Korea Institute of Information and Commucation 2008 한국정보통신학회논문지 Vol.12 No.4
무선 Ad hoc 네트워크에 지향성 안테나를 사용함으로써 간섭의 영향 감소, 공간재이용(spatial reuse) 증가, 그리고 통신용량 증가 등의 장점을 실현할 수 있다. 그러나 기존의 IEEE 802.11 MAC 프로토콜은 무지 향성 안테나를 고려하여 설계되었기 때문에 기존의 MAC 프로토콜을 지향성 안테나를 탑재한 무선 Ad hoc 네트워크에 적용할 경우 그 장점을 효율적으로 제공할 수 없다. 본 논문에서는 최적의 공간재이용을 통한 성능향상을 달성하기 위한 MAC 프로토콜을 제안하였으며, 시뮬레이션을 통하여 기존의 MAC과 통신효율과 종단간 지연을 비교하였다. Using directional antenna in wireless network can offer many advantages including significant decrease of interference, increase of spatial reuse and possibility of improving network capacity. However, existing 802.11 MAC is designed for use of omni-directional antenna then those advantages can not be shown in that MAC protocol when it uses directional antenna. In this paper, we present a MAC protocol specifically designed for directional antenna to achieve spatial reuse and improve capacity of MAC protocol. Simulation result shows the advantages of our proposal in comparison with existing MAC in terms of end-to-end delay and network throughput.