Hong C.,Nanjing Institute of Technology
Journal of Convergence Information Technology | Year: 2010
Traffic flow forecasting, the core element of intelligent transportation system, plays an important role in traffic information services and traffic guidance. Since neural network prediction needs plenty of training samples, it cannot guarantee the real-timeness of traffic flow forecasting. In this paper, a GMDH network was constructed by self-organization, and the network was applied to traffic flow forecasting, hence a GMDH-based traffic flow forecasting model. Owing to the fact that a GMDH network is trained without much prior knowledge, and the network structure is characterized by self-organization and globally-optimal selection, a short-time prediction model by the network has a good performance. The model was simulated with MATLAB, and the simulative results indicated that the model was the right tool for data-fitting. The average relative error of prediction was only 3.35%, and the model was valid.
Chen L.,Nanjing Institute of Technology
Dianli Zidonghua Shebei/Electric Power Automation Equipment | Year: 2011
The working principle of CT(Current Transducer) is introduced. Its mathematical model is built and its operating characteristics are analyzed with PSCAD /EMTDC, showing that the transient saturation is the main cause of CT error. According to the working principle of metering chip ADE7758, a simulation model of electronic energy meter is built and its simulative study is carried out based on the data measured in a traction substation, showing that the CT error induces larger energy measurement error, consistent with the theoretical analysis.
Yu J.,Institute of Technology and Engineering |
Zheng J.,Nanjing Institute of Technology
Energy Policy | Year: 2011
Based on independent studies, this paper focuses on the significant discrepancy of 15. GW between the installed onshore wind generation capacity and what has been actually connected to the power network to reveal the challenges in meeting the Chinese renewable energy target. The recent accidents in Chinese North-Western transmission network (in February-April, 2011) demonstrated the urgent need for a fundamental review of the Chinese renewable energy policy. Offshore wind has been identified as the most feasible alternative to onshore wind to help deliver electricity to Eastern China during the summer peak time. By investigating and summarizing first hand experiences of participation in the Chinese renewable market, the authors provide the economic figures of the first cohort of Chinese offshore wind schemes. Large state owned enterprises (SOE) are dominating the offshore wind development, repeating their previous practices on the land. While this paper acknowledges the critical role of offshore wind generation in meeting Chinese renewable energy targets, it envisages an installed offshore capacity of approximately 2000. MW by 2015, much less than the 10000. MW governmental estimation, which can be attributed to the lack of detailed energy policy, network constraints, offshore wind installation difficulties and quality issues in the manufacture of turbines. © 2011 Elsevier Ltd.
Ling Y.,Nanjing Institute of Technology
Advances in Information Sciences and Service Sciences | Year: 2012
A new positioning algorithm of wireless sensor route is proposed with the combination ant colony algorithm and mobile agent technology. At first the algorithm adopts nodes movement estimated algorithm and judges the possible subnets to which the mobile node transfers in advance; then reserve resources in subnet in advance, and judge the possible subnet to which the mobile nodes add according to the movement direction; finally the optimized route is acquired by adopting improved ant colony algorithm seeking system. In this way not only the limited bandwidth and power of wireless sensor network could be saved, but the issue that it is difficult to provide QoS security due to subnet switch could be solved. The simulation test indicates the proposed method could improve the resource utility for sensor network, decrease redundant data transfer efficiently, decrease communication consumption and propone the life cycle of network.
Li H.,Nanjing Institute of Technology |
Luo Y.,South China University of Technology |
Chen Y.,Utah State University
IEEE Transactions on Control Systems Technology | Year: 2010
In recent years, it is remarkable to see the increasing number of studies related to the theory and application of fractional order controller (FOC), specially PIλDμ controller, in many areas of science and engineering. Research activities are focused on developing new analysis and design methods for fractional order controllers as an extension of classical control theory. In this paper, a new tuning method for fractional order proportional and derivative (PD;mu; or FO-PD controller is proposed for a class of typical second-order plants. The tuned FO-PD controller can ensure that the given gain crossover frequency and phase margin are fulfilled, and furthermore, the phase derivative w. r. t. the frequency is zero, i.e., the phase Bode plot is flat at the given gain crossover frequency. Consequently, the closed-loop system is robust to gain variations. The FOC design method proposed in the paper is practical and simple to apply. Simulation and experimental results show that the closed-loop system can achieve favorable dynamic performance and robustness. © 2009 IEEE.