Han Jianghong

Dynamic economic dispatch for microgrids including battery energy storage

Microgrids integrate distributed renewable energy resources, controllable loads and energy storage in a more economic and reliable fashion. Battery energy storage units are essential for microgrid operation, which make microgird become a strong coupling system in the time domain. Hence, the traditional methods of static dispatch are no longer suitable for microgrids. This paper proposes a dynamic economic dispatch method. Considering microgrid as a discrete time system, the dynamic economic dispatch is to find the optimal control strategy for the system in finite time period. Based on this idea, the dynamic economic dispatch model for microgrids is established, and then the corresponding dynamic programming algorithm is designed. Finally, an example of microgrid is given, and the dynamic economic dispatch results are compared with that of the static dispatch. The comparison confirms the effectiveness of the proposed dynamic dispatch method.

Utilize Fuzzy Data Mining to Find the Travel Pattern of Browsers

With the traveling records of browsers, one can analyze the preference of pages, further understand the demands of consumers, and promote the advertising and marketing. In this study, we use maximum forward reference (MFR) algorithm to find the travel pattern of browsers from Web logs. Simultaneously, experts are asked to evaluate the fuzzy importance weightings for different Webs. At last, we employ fuzzy data mining technique that combines Apriori algorithm with fuzzy weights to determine the association rules. From the yielded association rules, one can be accurately aware of the information consumers need and which Webs they prefer. This is important to governmental institutions and enterprises. Enterprises can find the commercial opportunities and improve the design of Webs by means of this study. Governmental institutions can realize the needs of people from the obtained association rules, make the promotion of policy more efficiently, and provide better service quality

An extended model of Petri net and application in DEDS

The logic supervisor and structural supervisor based on controlled Petri net are difficult to model discrete event dynamic systems (DEDS) when the initial system state is uncertain or illegal. An extended Petri net is provided to solve the problem. The net (Jade-structure) just adjusts basic element of Petri net, and is adopted to model the open loop feedback control systems. The model of DEDS based on Jade-structure, is controlled by control conditions and makes system run in legal state space. The supervisor of Jade-structure based on system state (M-Jade) and the other supervisor based on the transition set of Jade-structure (T-Jade) are formally described, and M-Jade is extended to three extended models. The first extended model based on the subset of the place set, judges part of system current state and adjusts system state. The second based on the restriction inequations set of system state, judges the system current state equation and adjusts system state. The last adjusts system state by negative vectors. The controlled Jade-structure (C-Jade) based on T-Jade and M-Jade, models to DEDS with controlled places and uncontrolled places. When DEDS sets uncertain initial state, the controlled structure uses a set of restriction in-equations to avoid system running into illegal state place without computing the whole state place. If system meets abnormities, C-Jade structure makes system run back to permitted state place by negative vectors. And negative vectors and restriction in-equations also can be set by judging the marking of place subset. An example was modeled and validated by C-Jade, and the characteristics of C-Jade were discussed.

Application of Improved Genetic Algorithm in Virtual Enterprise Partnership Selection

Partner selection is a key problem of organizing a virtual enterprise. A multi-objective optimization model, which analyzes these candidate enterprises quantitatively is proposed and accomplished by an improved genetic algorithm. This algorithm sorts several single object fitness using quick-sorting algorithm and selects based on total fitness, crossovers and mutates using the self-adaptive probability, and finds the global optimal solution at last. Through comparison with standard GA and the improved self-adaptive GA, simulation example testifies the latter efficiency.

Quadratic Stabilization of Discrete Interval 2-D Systems

For discrete interval 2D systems, based on definition of quadratic stabilizability, sufficient and necessary quadratically stabilizable condition is given in terms of linear matrix inequalities. Quadratically stabilizing controller designing method is also proposed in this paper. The illustrative example shows the results are effective and less conservative.