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Search Results: 1 - 10 of 120209 matches for " Jiawei Wang "
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A Passivity-based Control for DC Motor Drive System with PWM
Jiawei Huang,Honghua Wang
TELKOMNIKA : Indonesian Journal of Electrical Engineering , 2012, DOI: 10.11591/telkomnika.v10i8.1695
Abstract: This paper investigates a passivity-based control (PBC) for DC Motor drive system with PWM. In the paper, the port-controlled Hamiltonian system with dissipation (PCHD) model of the system is built and the interconnection and damping assignment passivity-based control (IDA-PBC) method is used for the design of the controller. The system simulation model is built based on MATLAB/Simulink and the simulation results validate that the DC Motor drive system based on PBC controller has excellent dynamic performances such as robustness and transient response, compared with the traditional PI controller.
A Novel Synthesis of Arylpyrrolo[1,2-a]pyrazinone Derivatives
Fei Wang,Jiawei Wang,Shoufang Zhang
Molecules , 2004, DOI: 10.3390/90700574
Abstract: Some aryl-2-methyl-1-pyrrolo[1,2-a]pyrazinones were designed and prepared to study the Structure-Activity Relationships (SAR) of pyrrolo[1,2-a]pyrazinone derivatives. With methyl pyrrole-2-carboxylate as the starting material, the title compounds were prepared through N-alkylation and two novel cyclizations. Eleven aryl-2-methyl-1- pyrrolo[1,2-a]pyrazinone derivatives not previously reported in the literature are presented in this paper. Some of them show potent anti-inflammatory and analgesic activities.
Subchronic Exposure of Apigenin Induces Hepatic Oxidative Stress in Male Rats  [PDF]
Jiawei Liu, Yuhong Wang, Wencai Chen, Sheng Li, Lingfei Liu, Yuhui Dang, Zhilan Li
Health (Health) , 2014, DOI: 10.4236/health.2014.610124
Abstract: Apigenin (4’, 5, 7-trihydroxyflavone, AP), a dietary flavonoid, is reported to have several therapeutic effects in different diseases including cancer. In the present study, in order to explore the potential mechanism and provide the references for further studies, we investigated the effect of apigenin at various dosages on the hepatic oxidative stress of male rats. Totally 48 SD male rats were randomly divided into control group (saline, 1 ml/100g·bw), low-dose group (AP, 234 mg/kg·bw), middle-dose group (AP, 468 mg/kg·bw) and high-dose group (AP, 936 mg/kg·bw). The rats were administered with apigenin or saline via intragastriation once a day, 6 days per week, and 5 consecutive weeks. Rats were sacrificed and the livers were harvested and then immediately preserved at ﹣20°C. Liver homogenate was prepared before detection. Hepatic malondialdehyde (MDA), nitric oxide syntheses (NOS), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), total antioxidant capacity (T-AOC) and glutathione (GSH) were determined by colorimetric methods according to the provided procedures. The weights of liver and spleen in apigenin treatment groups did not reveal statistically significant difference when compared with that in the control group (P > 0.05). Total protein (TP), albumin (ALB) and globulin (GLO) in apigenin treatment groups were significantly lower than those in the control group (P < 0.05). SOD in the middle-dose group (AP, 468 mg/kg·bw) and high-dose group (AP, 936 mg/kg·bw) were significantly higher than that in the control group (P < 0.05). T-AOC, CAT and GSH-Px in apigenin treatment groups were significantly lower than those in the control group (P < 0.05). In high-dose AP group (AP, 936 mg/kg·bw), apigenin can result in the reduction of T-AOC, thus leading to the oxidative damage of liver tissues. In contrast, in middle-dose AP group (AP, 468 mg/kg·bw), apegenin can reduce the elimination capacity of oxygen free radicals.
A projection method for approximating fixed points of quasi nonexpansive mappings without the usual demiclosedness condition
Heinz H. Bauschke,Jiawei Chen,Xianfu Wang
Mathematics , 2012,
Abstract: We introduce and analyze an abstract algorithm that aims to find the projection onto a closed convex subset of a Hilbert space. When specialized to the fixed point set of a quasi nonexpansive mapping, the required sufficient condition (termed "fixed-point closed") is less restrictive than the usual conditions based on the demiclosedness principle. A concrete example of a subgradient projector is presented which illustrates the applicability of this generalization.
A Bregman projection method for approximating fixed points of quasi-Bregman nonexpansive mappings
Heinz H. Bauschke,Jiawei Chen,Xianfu Wang
Mathematics , 2013,
Abstract: We introduce an abstract algorithm that aims to find the Bregman projection onto a closed convex set. As an application, the asymptotic behaviour of an iterative method for finding a fixed point of a quasi Bregman nonexpansive mapping with the fixed-point closedness property is analyzed. We also show that our result is applicable to Bregman subgradient projectors.
Enhancing Wind Power Integration through Optimal Use of Flexibility in Multi-Carrier Energy Systems from the Danish Perspective  [PDF]
Yi Zong, Awadelrahman M. A. Ahmed, Jiawei Wang, Shi You, Chresten Tr?holt, Xianyong Xiao
World Journal of Engineering and Technology (WJET) , 2017, DOI: 10.4236/wjet.2017.54B009
Abstract:
Denmark’ goal of being independent of fossil energy sources in 2050 puts forward great demands on all energy subsystems (electricity, heat, gas and transport, etc.) to be operated in a holistic manner. The Danish experience and challenges of wind power integration and the development of district heating systems are summarized in this paper. How to optimally use the cross-sectoral flexibility by intelligent control (model predictive control-based) of the key coupling components in an integrated heat and power system including electrical heat pumps in the demand side, and thermal storage applications in buildings is investigated.
Crystal structure of the MH2 domain of Drosophila Mad
Chong Wang,Lei Chen,Le Wang,JiaWei Wu
Science China Life Sciences , 2009, DOI: 10.1007/s11427-009-0080-x
Abstract: The decapentaplegic(Dpp), a member of the TGF-β superfamily, plays a pivotal role in the control of proliferation, global patterning and induction of specific cell fates during Drosophila development. Mother against Dpp(Mad) is the founding member of the conserved Smad protein family which specifically transduces the intracellular TGF-β signaling cascade. Here we report the 2.80 structure of the MH2 domain of Mad(Mad-MH2) that was readily superposed to the mammal Smad-MH2 structures. This unphosphorylated Mad-MH2 forms a symmetric homotrimer in crystals, consistent with the result of the size-exclusion chromatography that Mad-MH2 exhibited a propensity for concentration-dependent oligomerization prior to phosphorylation. Structural analysis revealed that the formation of homotrimeric Mad-MH2 is mainly mediated by contacts involving the extreme C-terminal SSVS motif, and is strengthened by phosphorylation of the last two Ser residues which was confirmed by the gel filtration analysis of the pseudophosphorylated Mad-MH2(DVD). Intriguingly, the homotrimer within an asymmetric unit only possesses two ordered C-terminal tails, reminiscent of the arrangement of the R-Smad/Smad4 complexes, indicating that the subunit with a flexible SSXS motif would be readily replaced by Co-Smad to form a functional heterotrimer.
Crystal Structure of the MH2 domain of Drosophila Mad

WANG Chong,CHEN Lei,WANG Le &,WU JiaWei,

中国科学C辑(英文版) , 2009,
Abstract: The decapentaplegic(Dpp), a member of the TGF-β superfamily, plays a pivotal role in the control of proliferation, global patterning and induction of specific cell fates during Drosophila development. Mother against Dpp(Mad) is the founding member of the conserved Smad protein family which specifically transduces the intracellular TGF-β signaling cascade. Here we report the 2.80 ? structure of the MH2 domain of Mad(Mad-MH2) that was readily superposed to the mammal Smad-MH2 structures. This unphosphorylated Mad-MH2 forms a symmetric homotrimer in crystals, consistent with the result of the size-exclusion chromatography that Mad-MH2 exhibited a propensity for concentration-dependent oligomerization prior to phosphorylation. Structural analysis revealed that the formation of homotrimeric Mad-MH2 is mainly mediated by contacts involving the extreme C-terminal SSVS motif, and is strengthened by phosphorylation of the last two Ser residues which was confirmed by the gel filtration analysis of the pseudophosphorylated Mad-MH2(DVD). Intriguingly, the homotrimer within an asymmetric unit only possesses two ordered C-terminal tails, reminiscent of the arrangement of the R-Smad/Smad4 complexes, indicating that the subunit with a flexible SSXS motif would be readily replaced by Co-Smad to form a functional heterotrimer. Supported by National Key Basic Research and Development Program of China (Grant Nos. 2006CB503900 and 2007CB914400) and China National Funds for Distinguished Young Scientists (Grant No. 30425005).
Exploring The Contribution of Unlabeled Data in Financial Sentiment Analysis
Jimmy SJ. Ren,Wei Wang,Jiawei Wang,Stephen Shaoyi Liao
Computer Science , 2013,
Abstract: With the proliferation of its applications in various industries, sentiment analysis by using publicly available web data has become an active research area in text classification during these years. It is argued by researchers that semi-supervised learning is an effective approach to this problem since it is capable to mitigate the manual labeling effort which is usually expensive and time-consuming. However, there was a long-term debate on the effectiveness of unlabeled data in text classification. This was partially caused by the fact that many assumptions in theoretic analysis often do not hold in practice. We argue that this problem may be further understood by adding an additional dimension in the experiment. This allows us to address this problem in the perspective of bias and variance in a broader view. We show that the well-known performance degradation issue caused by unlabeled data can be reproduced as a subset of the whole scenario. We argue that if the bias-variance trade-off is to be better balanced by a more effective feature selection method unlabeled data is very likely to boost the classification performance. We then propose a feature selection framework in which labeled and unlabeled training samples are both considered. We discuss its potential in achieving such a balance. Besides, the application in financial sentiment analysis is chosen because it not only exemplifies an important application, the data possesses better illustrative power as well. The implications of this study in text classification and financial sentiment analysis are both discussed.
An Unsupervised Feature Learning Approach to Improve Automatic Incident Detection
Jimmy SJ. Ren,Wei Wang,Jiawei Wang,Stephen Liao
Computer Science , 2013,
Abstract: Sophisticated automatic incident detection (AID) technology plays a key role in contemporary transportation systems. Though many papers were devoted to study incident classification algorithms, few study investigated how to enhance feature representation of incidents to improve AID performance. In this paper, we propose to use an unsupervised feature learning algorithm to generate higher level features to represent incidents. We used real incident data in the experiments and found that effective feature mapping function can be learnt from the data crosses the test sites. With the enhanced features, detection rate (DR), false alarm rate (FAR) and mean time to detect (MTTD) are significantly improved in all of the three representative cases. This approach also provides an alternative way to reduce the amount of labeled data, which is expensive to obtain, required in training better incident classifiers since the feature learning is unsupervised.
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