GPIO BASED SLIDING MODE CONTROL FOR DIESEL ENGINE HIGH PRESSURE COMMON RAIL SYSTEM

Zheng Yuan,Chen Dai,Hao Sun,Shihua Li,Bifeng Yin 한국자동차공학회 2023 International journal of automotive technology Vol.24 No.1

With the rapid development of diesel engines, reducing the pressure fluctuation of the common rail has become a key factor to improve the performance of the high pressure common rail (HPCR) system. Among traditional rail pressure control approaches, the influence of time-varying disturbances on the HPCR system is not fully considered and is not well dealt with. To this end, a nonlinear model of the HPCR system is firstly established based on fluid dynamics and mechanics laws. And a composite controller based on the nonlinear model is proposed. It consists of two parts: 1) A sliding mode feedback part; 2) A disturbance feedforward compensation part based on a generalized proportional integral observer. Finally, a group of test is simulated in the AMESim simulation environment and the results are shown to demonstrate the effectiveness of the proposed method.

Hepatitis C Virus Nonstructural 5A Protein (HCV-NS5A) Inhibits Hepatocyte Apoptosis through the NF-κb/miR-503/bcl-2 Pathway

Zhengyuan Xie,Zhihua Xiao,Fenfen Wang 한국분자세포생물학회 2017 Molecules and cells Vol.40 No.3

The nonstructural protein 5A (NS5A) encoded by the human hepatitis C virus (HCV) RNA genome is a multifunctional phosphoprotein. To analyse the influence of NS5A on apoptosis, we established an Hep-NS5A cell line (HepG2 cells that stably express NS5A) and induced apoptosis using tumour necrosis factor (TNF)-. We utilised the MTT assay to detect cell viability, real-time quantitative polymerase chain reaction and Western blot to analyse gene and protein expres-sion, and a luciferase reporter gene experiment to investigate the targeted regulatory relationship. Chromatin immunoprecipitation was used to identify the combination of NF-B and miR-503. We found that overexpression of NS5A inhibited TNF--induced hepatocellular apoptosis via regulating miR-503 expression. The cell viability of the TNF- induced Hep-mock cells was significantly less than the viability of the TNF- induced Hep-NS5A cells, which demonstrates that NS5A inhibited TNF--induced HepG2 cell apoptosis. Under TNF- treatment, miR-503 expression was decreased and cell viability and B-cell lymphoma 2 (bcl-2) expression were increased in the Hep-NS5A cells. Moreover, the luciferase reporter gene experiment verified that bcl-2 was a direct target of miR-503, NS5A inhibited TNF--induced NF-B activation and NF-B regulated miR-503 transcription by combining with the miR-503 promoter. After the Hep-NS5A cells were transfected with miR-503 mimics, the data indicated that the mimics could reverse TNF--induced cell apoptosis and blc-2 expression. Collectively, our findings suggest a possible molecular mechanism that may contribute to HCV treatment in which NS5A inhibits NF-B activation to decrease miR-503 expression and increase bcl-2 expression, which leads to a decrease in hepatocellular apoptosis.

Geographic Concentration of Advertising Industry in East Asia

Zhao Zhengyuan 대한지리학회 2011 대한지리학회 컨퍼런스 자료집 Vol.- No.6

Hepatitis C Virus Nonstructural 5A Protein (HCV-NS5A) Inhibits Hepatocyte Apoptosis through the NF-κb/miR-503/bcl-2 Pathway

Xie, Zhengyuan,Xiao, Zhihua,Wang, Fenfen Korean Society for Molecular and Cellular Biology 2017 Molecules and cells Vol.40 No.3

The nonstructural protein 5A (NS5A) encoded by the human hepatitis C virus (HCV) RNA genome is a multifunctional phosphoprotein. To analyse the influence of NS5A on apoptosis, we established an Hep-NS5A cell line (HepG2 cells that stably express NS5A) and induced apoptosis using tumour necrosis factor $(TNF)-{\alpha}$. We utilised the MTT assay to detect cell viability, real-time quantitative polymerase chain reaction and Western blot to analyse gene and protein expression, and a luciferase reporter gene experiment to investigate the targeted regulatory relationship. Chromatin immunoprecipitation was used to identify the combination of $NF-{\kappa}B$ and miR-503. We found that overexpression of NS5A inhibited $TNF-{\alpha}$-induced hepatocellular apoptosis via regulating miR-503 expression. The cell viability of the $TNF-{\alpha}$ induced Hep-mock cells was significantly less than the viability of the $TNF-{\alpha}$ induced Hep-NS5A cells, which demonstrates that NS5A inhibited $TNF-{\alpha}$-induced HepG2 cell apoptosis. Under $TNF-{\alpha}$ treatment, miR-503 expression was decreased and cell viability and B-cell lymphoma 2 (bcl-2) expression were increased in the Hep-NS5A cells. Moreover, the luciferase reporter gene experiment verified that bcl-2 was a direct target of miR-503, NS5A inhibited $TNF{\alpha}$-induced $NF-{\kappa}B$ activation and $NF-{\kappa}B$ regulated miR-503 transcription by combining with the miR-503 promoter. After the Hep-NS5A cells were transfected with miR-503 mimics, the data indicated that the mimics could reverse $TNF-{\alpha}$-induced cell apoptosis and blc-2 expression. Collectively, our findings suggest a possible molecular mechanism that may contribute to HCV treatment in which NS5A inhibits $NF-{\kappa}B$ activation to decrease miR-503 expression and increase bcl-2 expression, which leads to a decrease in hepatocellular apoptosis.

Performance Analysis of Blind Channel Estimation for Precoded Multiuser Systems

Xu, Zhengyuan The Korea Institute of Information and Commucation 2002 Journal of communications and networks Vol.4 No.3

Precoder has been shown to be able to provide source diversity and design flexibility. In this paper we employ precoding techniques for block transmission based on a multirate filterbank structure. To accommodate multiuser communication with variable data rates, different precoders with corresponding coefficients and up/down sampling rates are used. However, due to unknown multipath distortion, different interferences may exist in the received data, such as multiuser interference, intersymbol interference and interblock interference. To estimate channel parameters for a desired user, we employ all structured signature waveforms associated with different symbols of that user and apply subspace techniques. Therefore better performance of channel estimator can be achieved than the conventional subspace method based only on the signature of the current symbol. The delay for that user can also be jointly estimated. Channel identifiability conditions and asymptotic channel estimation error are investigated in detail. Numerical examples are provided to justify the proposed method. gest either multicode (MC) or multiple processing gain (MPG) mechanism [2], while requiring data rates to be integral multiples of some basic low-rate. In order to support variable rate transmission however, a comprehensive scheme needs to be investigated.

Effects of N-Acetylcysteine on Nicotinamide Dinucleotide Phosphate Oxidase Activation and Antioxidant Status in Heart, Lung, Liver and Kidney in Streptozotocin-Induced Diabetic Rats

Shaoqing Lei,Zhengyuan Xia,Huimin Liu,Hong Yu,Hui Wang,Yanan Liu 연세대학교의과대학 2012 Yonsei medical journal Vol.53 No.2

Purpose: Hyperglycemia increases reactive oxygen species (ROS) and the resulting oxidative stress plays a key role in the pathogenesis of diabetic complications. Nicotinamide dinucleotide phosphate (NADPH) oxidase is one of the major sources of ROS production in diabetes. We, therefore, examined the possibility that NADPH oxidase activation is increased in various tissues, and that the antioxidant N-acetylcysteine (NAC) may have tissue specific effects on NADPH oxidase and tissue antioxidant status in diabetes. Materials and Methods: Control (C) and streptozotocin-induced diabetic (D) rats were treated either with NAC (1.5 g/kg/day) orally or placebo for 4 weeks. The plasma, heart, lung, liver, kidney were harvested immediately and stored for biochemical or immunoblot analysis. Results: levels of free 15-F2t-isoprostane were increased in plasma, heart, lung, liver and kidney tissues in diabetic rats, accompanied with significantly increased membrane translocation of the NADPH oxidase subunit p67phox in all tissues and increased expression of the membrane-bound subunit p22phox in heart, lung and kidney. The tissue antioxidant activity in lung, liver and kidney was decreased in diabetic rats, while it was increased in heart tissue. NAC reduced the expression of p22phox and p67phox, suppressed p67phox membrane translocation, and reduced free 15-F2t-isoprostane levels in all tissues. NAC increased antioxidant activity in liver and lung, but did not significantly affect antioxidant activity in heart and kidney. Conclusion: The current study shows that NAC inhibits NADPH oxidase activation in diabetes and attenuates tissue oxidative damage in all organs, even though its effects on antioxidant activity are tissue specific.

흐름 다중 심벌 검파를 사용한 트렐리스 부호화된 $\pi$/8 shift 8PSK-OFDM

안필승,김종일,김한종,Zhengyuan Xu 한국정보통신학회 2002 한국정보통신학회논문지 Vol.6 No.4

In this paper, we propose $\pi$/8 shift 8PSK and trellis-coded $\pi$/8 shift 8PSK-OFDM techniques by applying $\pi$/4 shift QPSK to trellis-coded modulation (TCM), and performing signal set expansion and set partition correspondingly based on phase difference. In our Viterbi decoding algorithm, up to L phase differences from successively received symbols are employed in the new branch metrics. Such sliding multiple symbol detection (SMSD) method provides improved bit-error-rate (BER) performance in the differential detection of the trellis-coded $\pi$/8 shift 8PSK-OFDM signals. The performance improvements are achieved for different communication channels without sacrificing bandwidth and power efficiency. It thus makes the proposed modulation and sliding detection scheme more attractive for power and band-limited systems. 본 논문에서는 $\pi$/4 shift QPSK를 트렐리스 부호화 변조에 적용시키기 위해 $\pi$/8 shift 8PSK와 BER 특성을 향상시키기 위한 트렐리스 부호화된 $\pi$/8 shift 8PSK-OFDM을 제안한다. 트렐리스 부호화 변조는 위상차에 의한 신호 집합 확장과 분할을 수행한다. 수신측에서 슬라이딩 방식의 다중 심벌 검파를 수행하기 위해서 연속 수신된 신호로부터 L개의 위상차를 추출하고 이를 이용한 비터비 디코더를 설계한다. 슬라이딩 방식의 다중 심벌 검파는 트렐리스 부호화된 $\pi$/8 shift 8PSK-OFDM에서 향상된 BER 성능을 보여준다. 본 논문에서 제안한 다중 심벌 검파를 이용한 $\pi$/8 shift 8PSK-OFDM은 대역폭과 전력의 효율성을 감소시키지 않고 같은 SNR에서 BER 성능을 향상시킬 수 있다는 것을 보여준다. 또한 제안된 디코더 방식과 알고리듬은 다중 반송파뿐만 아니라 전통적인 단일 반송파 변조에도 사용될 수 있다.

Variance function estimation of a one-dimensional nonstationary process

Eunice J. Kim,Zhengyuan Zhu 한국통계학회 2019 Journal of the Korean Statistical Society Vol.48 No.3

We propose a flexible nonparametric estimation of a variance function from a onedimensional process where the process errors are nonstationary and correlated. Due to nonstationarity a local variogram is defined, and its asymptotic properties are derived. We include a bandwidth selection method for smoothing taking into account the correlations in the errors. We compare the proposed difference-based nonparametric approach with Anderes and Stein(2011)’s local-likelihood approach. Our method has a smaller integrated MSE, easily fixes the boundary bias, and requires far less computing time than the likelihood-based method.

Adaptive Sliding Mode Based Disturbance Attenuation Tracking Control for Wheeled Mobile Robots

Kang Liu,Hongbo Gao,Haibo Ji,Zhengyuan Hao 제어·로봇·시스템학회 2020 International Journal of Control, Automation, and Vol.18 No.5

This paper is devoted to investigating a composite controller for wheeled mobile robots in the presence of external disturbance and parametric uncertainty. Unlike the traditional backstepping technique existing the impractical velocity jumps, the proposed neural dynamic model has the ability to generate smooth continuous signals. Subsequently, a disturbance observer based adaptive sliding mode dynamic controller is introduced to estimate disturbances online, adjust control gain automatically and eliminate chattering phenomena completely. Under the developed control law, the ultimate boundedness of all signals is guaranteed and the tracking errors can be arbitrarily small in finite time. Simulation results are carried out to demonstrate the effectiveness of the proposed scheme.

Effects of Multiple Antennas on Outage Performance of Decode-and-Forward Cooperative Networks with Relay Selection

LEE, Wooju,YOON, Dongweon,XU, Zhengyuan The Institute of Electronics, Information and Comm 2011 IEICE TRANSACTIONS ON COMMUNICATIONS - Vol.eb94 No.11

<P>In this paper, we consider multiple source and destination antennas based on relay selection scheme to improve the end-to-end outage performance for decode-and-forward cooperative networks. We derive an exact closed-form expression of the outage probability for the proposed system over a Rayleigh fading channel and describe the diversity-multiplexing tradeoff of the system. We then analyze the effects of the number of source and destination antennas on the outage probabilities and diversity-multiplexing tradeoffs.</P>