Systems Engineering - Theory & Practice最新文献

By integrated application of system dynamics feedback dynamic complexity analysis method and agricultural engineering, environment engineering and other disciplines, we exploited the “Pig-biogas-energy” circular engineering in the base and created the “aerobic digester effluent third class filter delay storage and diffluence from the irrigating water engineering.”. After having proved that there still existing serious pollution” with SD delay function theory, we established five new breeding and planting biology chains circular production engineering techniques and three organizing and managing techniques. After the whole systems engineering were put into practice, the region obtains comprehensive benefit in environment, economy, and society, and the building of harmonious society was promoted.

According to the homeomorphic property between fuzzy number space and the family of standard monotone functions on [−1,1], comparison of fuzzy numbers can be transformed into comparison of standard monotone functions on [−1,1]. Some order relations on the fuzzy number space are defined by using the method of fuzzy structured element, and some properties of the order relations are discussed. At last, an example is designed.

In evolutionary games, it becomes more difficult to choose optimal strategies for players because of incomplete information and bounded rationality. For bounded rational players, how to maximize the expected sum of payoffs by learning and changing strategies is an important question in evolutionary game theory. Reinforcement learning does not need a model of its environment and can be used online, it is well-suited for problems with incomplete and uncertain information. Evolutionary game theory is the subject about the decision problems of multiagent with incomplete information. In this article, reinforcement learning is introduced in evolutionary games, multiagent reinforcement learning model is constructed, and the learning algorithm is presented based on Q-learning. The results of simulation experiments show that the multiagent reinforcement learning model can be applied successfully in evolutionary games for finding the optimal strategies.

From the production of GM (1,1) grey derivative, this article arguments logically the rationality of using weighted average of forward difference quotient and backward difference quotient as GM(1,1) grey derivative whitenization value in the theories. It gives the concrete expression type of weighted coefficient and builds up a new GM(1,1) model. It proves that the new model has the white exponential coincidence law in theory and puts forward a new method to solve parameters of the new model. Simulation and prediction of practice examples show that this model and method are useful and effective.

Combining the theory of Copula with statistics of extremes, this paper studied the dependence between drainage area and drainage height difference of the six relief factors of debris flow. The correlation coefficient Kendall's τ, Spearman's ρ, and the tail association measure χ have been calculated. Moreover, in order to describe the extreme dependent structure about the two relief factors comprehensively, this paper makes a bivariate exceedance model and gives the tail distribution and the parameter estimation methods. Finally, as examples, this paper analyses the dependence of relief factors of the debris flow.

In order to control uncertainty and instability of single classifiers in financial distress prediction, this research proposed a multiple classifiers hybrid combination model for financial distress prediction. This model improves predictive performance by the combination of multiple classifiers and taking advantages of serial combination and parallel combination. Diversity principle and individual optimization principle were taken as criteria for classifier selection. On the foundation of defining selection operator for class's best classifier, algorithm for constructing basic modules in hybrid combination, dynamic weighting mechanism for parallel modules inside hybrid combination, and mechanism of majority voting were designed. Empirical research with data from Chinese listed companies indicates that the model improves average predictive accuracy and simultaneously reduces variation degree. Statistical analysis demonstrates that the hybrid combination model outperforms existing single classifiers in financial distress prediction significantly.

This article employs the schemes of structural change test on time series of export, import, and net export of China sampled from January 1981 to December 2006 to investigate effects of the change of international trade environment and domestic policy on the foreign trade. By constructing test models, Critical values for unit-root test against piecewise-trend stationarity with two endogenous breakpoints are created for all the six alternative specifications on Mont Carlo simulation. It was revealed in the result that although the import from 1981 to 2006 was a unit root series determined by the growth of the economy, the export was a piecewise stationary series that suffered two or more breaks, one of which was collected in mid-2001 associated to the entrance to the WTO, and the others on February 1994, July 19967, and November 1997, respectively correlated to their corresponding events.

This article involves the multimode project payment scheduling problem where activities can be performed with several discrete modes and the objective is to maximize the net present value (NPV) of the client. The assumptions are identified and the notations are defined at first. Then, the optimization model of the problem is constructed and its strong NP-hardness is proved by simplifying it to the subproblem of the discrete time/cost tradeoff problem. On the basis of the characteristic of the problem, a special heuristic algorithm composed of two modules is developed. Through the iteration between the two modules, the heuristic can find the desirable solution for the problem. The heuristic is tested on a data set consisting of 40 instances generated randomly. On the basis of the results obtained, the following conclusions can be drawn: All the instances can be solved within 24.63 seconds; the relative deviation of the objective function value from its upper bound is not greater than 8.24%; the NPV of the client decreases with the increase of the payment number, the interest rate per period, the profit margin of the contractor, or the payment proportion.

Considering the current situation of Chinese ports and from the port company's point of view, this brief figured out the main factors influencing Chinese port X-efficiency and established the X-efficiency measure model with help of stochastic frontier method, which filled the theoretical gap of port X-efficiency research. On that basis, this brief studied the data of 13 typical port-listed-companies such as Shenchiwan A that stood for the five biggest port clusters in China. The result proved some main factors influencing Chinese port X-efficiency such as the internal incentive system of port-listed companies. Finally, suggestions for improving the Chinese ports X-efficiency were proposed, such as reforming the staff incentive system and company ownership system.