Zhou S.,Shandong Jiaotong University |
Zhang Y.,Shandong Green Energy Gas Industrial Co. |
Dong Y.,Shandong University
Energy | Year: 2012
Stack-pretreatment is introduced to gain higher biogas production from corn stover through solid state anaerobic digestion. The purpose of this study is to find the effects of naturally microbial pretreatment on stalk lignin, cellulose and hemicellulose degradation, and biogas production. The result indicates that the corn straws which had been stack-pretreated for 20 days decreases of the content of the middle corn straws cellulose, hemi-cellulose and lignin by 5.8%, 16.8% and 5.7% respectively lower than that of the untreated samples.The highest cumulative biogas yield for 60-day digestion was obtained in B group, which was 23.2% higher than that of A group, 29.1% higher than H group and also 40.7% higher than I group. The result indicates the biogas yield of anaerobic digestion of the pretreated corn stover mixed with cow dung is higher than that of the untreated ones mixed with cow dung, and higher than that of the untreated ones alone, also higher than the cow dung alone. The biogas yield of the pretreated corn stover mixed with cow is higher than the pretreated ones with the sludge. © 2012 Elsevier Ltd.
Leng Y.,Shandong Normal University |
Xu X.,Shandong College of Electronic Technology |
Qi G.,Shandong Jiaotong University
Knowledge-Based Systems | Year: 2013
One key issue for most classification algorithms is that they need large amounts of labeled samples to train the classifier. Since manual labeling is time consuming, researchers have proposed technologies of active learning and semi-supervised learning to reduce manual labeling workload. There is a certain degree of complementarity between active learning and semi-supervised learning, and therefore some researches combine them to further reduce manual labeling workload. However, researches on combining active learning and semi-supervised learning for SVM classifier are rare. Of numerous SVM active learning algorithms, the most popular is the one that queries the sample closest to the current classification hyperplane in each iteration, which is denoted as SVMAL in this paper. Realizing that SVMAL is only interested in samples that are more likely to be on the class boundary, while ignoring the usage of the rest large amounts of unlabeled samples, this paper designs a semi-supervised learning algorithm to make full use of the rest non-queried samples, and further forms a new active semi-supervised SVM algorithm. The proposed active semi-supervised SVM algorithm uses active learning to select class boundary samples, and semi-supervised learning to select class central samples, for class central samples are believed to better describe the class distribution, and to help SVMAL finding the boundary samples more precisely. In order not to introduce too many labeling errors when exploring class central samples, the label changing rate is used to ensure the reliability of the predicted labels. Experimental results show that the proposed active semi-supervised SVM algorithm performs much better than the pure SVM active learning algorithm, and thus can further reduce manual labeling workload. © 2013 Elsevier B.V. All rights reserved.
Yang R.,Shandong University |
Yang R.,Shandong Jiaotong University |
Wang Y.,Shandong University
Automatica | Year: 2013
This paper investigates the finite-time stability (FTS) analysis and finite-time H control design for a class of nonlinear time-delay Hamiltonian systems, and proposes some delay-dependent results on both the FTS and finite-time control design. First, a criterion on the FTS is proposed for general time-delay nonlinear systems via the Razumikhin approach. Then, based on the criterion, some delay-independent and delay-dependent conditions on the FTS are derived for the nonlinear time-delay Hamiltonian systems by constructing a suitable Lyapunov function. Third, we use the obtained FTS results to investigate the finite-time H control problem, and present a control design procedure for a class of nonlinear time-delay port-controlled Hamiltonian systems by the energy-shaping approach. Study of two illustrative examples shows that the results obtained in this paper work very well in the FTS analysis and control design of some nonlinear time-delay Hamiltonian systems. © 2012 Elsevier Ltd. All rights reserved.
Zhang G.,Shandong Jiaotong University
Lecture Notes in Electrical Engineering | Year: 2014
Car collision is now the traffic accident with higher incidence and more death. In the process of collision between large trucks and cars, the cars are likely to drill into the trucks in the front or in the back and be compacted on the side due to the high frame of the trucks. What's more, the quality of trucks is much larger than small cars, which will lead to the problem of compatibility. © 2014 Springer-Verlag.
Zhu W.-X.,Shandong University |
Zhang L.-D.,Shandong University |
Zhang L.-D.,Shandong Jiaotong University
Physica A: Statistical Mechanics and its Applications | Year: 2014
A speed feedback control mechanism was introduced into the system to improve the dynamical performance of the traffic flow. The modern control theory was used to analyze the stability of the system. It is found that the stability region varies with the feedback coefficient proportionally. In addition, the unit step responses in time domain and phase-frequency curves in frequency domain were given with different feedback coefficients in step response diagram and Bode diagram respectively. The overshoot and phase margins are inversely proportional to the speed feedback coefficients in an underdamped condition. The simulations were conducted to verify the validity of the improvement. The conclusion can be drawn that the analytical result and the simulation result are in good agreement with each other. © 2014 Elsevier B.V. All rights reserved.