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201.
A STAGE-STRUCTURED SI ECO-EPIDEMIOLOGICAL MODEL WITH TIME DELAY AND IMPULSIVE CONTROLLING* 总被引:1,自引:0,他引:1
This paper formulates a robust stage-structured SI eco-epidemiological model with periodic constant pulse releasing of infectious pests with pathogens. The authors show that the conditions for global attractivity of the 'pest-eradication' periodic solution and permanence of the system depend on time delay, hence, the authors call it "profitless". Further, the authors present a pest management strategy in which the pest population is kept under the economic threshold level (ETL) when the pest population is uniformly persistent. By numerical analysis, the authors also show that constant maturation time delay for the susceptible pests and pulse releasing of the infectious pests can bring obvious effects on the dynamics of system. 相似文献
202.
The authors concern robust model predictive control for linear continuous systems with polytopic uncertainties and input constraints. At each sampling time, a piecewise constant control sequence is obtained by solving a set of linear matrix inequalities. The sufficient conditions on the existence of the model predictive control are given, and the robust stability of the closed-loop systems is guaranteed. A simulation example illustrates the efficiency of the proposed method. 相似文献
203.
Participatory Sustainability Impact Assessment: Scientific Policy Advice as a Social Learning Process 总被引:3,自引:3,他引:0
Manuel Gottschick 《Systemic Practice and Action Research》2008,21(6):479-495
This paper deals with the development of scientific policy advice by providing a methodology to foster a social learning process.
The methodology, called participatory Sustainability Impact Assessment (pSIA), aims to structure complex problem situations,
to clarify interests and basic assumptions, to interpret scientific studies, to develop impact assessment, and to explore
sensitivity of uncertainty and lack of information. In pSIA workshops the participants are supposed to build conceptual models
with different modelling methods, like System Dynamics, Value Chain Analysis, and Morphological Analysis. A case study is
presented that describes a workshop series with political as well as academic actors, applying the pSIA approach to an impact
assessment of Economic Partnership Agreements between the European Union and the Eastern and Southern Africa Region.
相似文献
Manuel GottschickEmail: URL: www.agchange.de |
204.
In this paper we extend Taub (1979) approach for prediction in the context of the variance components model. The extension obtained is based on the two‐way random‐effect model with heteroskedasticity. Prediction functions are then obtained in three heteroskedasticity cases (heteroskedasticity on the individual term , heteroskedasticity on the composite term ?it, and heteroskedasticity on the temporal term ). Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
205.
We present a system for combining the different types of predictions given by a wide category of mechanical trading rules through statistical learning methods (boosting, and several model averaging methods like Bayesian or simple averaging methods). Statistical learning methods supply better out‐of‐sample results than most of the single moving average rules in the NYSE Composite Index from January 1993 to December 2002. Moreover, using a filter to reduce trading frequency, the filtered boosting model produces a technical strategy which, although it is not able to overcome the returns of the buy‐and‐hold (B&H) strategy during rising periods, it does overcome the B&H during falling periods and is able to absorb a considerable part of falls in the market. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
206.
Joseph W. Dauben 《Archive for History of Exact Sciences》2008,62(2):91-178
In December and January of 1983–1984, archaeologists excavating the tomb of an ancient Chinese provincial bureaucrat at a
Western Han Dynasty site near Zhangjiashan, in Jiangling county, Hubei Province, discovered a number of books on bamboo strips,
including inter alia works on legal statutes, military practice, and medicine. Among these was a previously unknown mathematical work on some
200 bamboo strips, the
Suan shu shu, or Book of Numbers and Computations. Based upon other works found in the tomb, especially a copy of the
Er nian lü ling (Laws and Decrees of the Second Year (of the reign of empress Lü, i.e. Lü Hou)), archaeologists have dated the tomb to ca. 186 BCE (Lü Hou’s regency lasted from 188 to 180 BCE). The Suan shu shu, as the earliest yet discovered work devoted specifically to mathematics from ancient China, has stirred considerable interest
among Chinese historians of science. The translation and commentary offered here draw extensively on the works cited in Sect.
3 below. Several appendixes devoted to specific issues related to translating the Suan shu shu, including its title and the problem of determining English equivalents for various commodities that arise in the text, may
be found in Appendix II.
An erratum to this article can be found at 相似文献
207.
COMPARISON OF TWO METHODS OF OPERATING THEATRE PLANNING: APPLICATION IN BELGIAN HOSPITAL 总被引:3,自引:0,他引:3
Sondes CHAABANE~ Nadine MESKENS~ Alain GUINET~ Marius LAURENT~ ~LAMIH laboratory Valenciennes University Valenciennes Cedex France ~MAAD Laboratory FUCAM Mons Belgium ~LIESP Laboratory INSA-Lyon France ~CHU de TIVOLI La Louvière Belgium 《系统科学与系统工程学报(英文版)》2008,17(2):171-186
Operating Theatre is the centre of the hospital management's efforts. It constitutes the most expensive sector with more than 10% of the intended operating budget of the hospital. To reduce the costs while maintaining a good quality of care, one of the solutions is to improve the existent planning and scheduling methods by improving the services and surgical specialty coordination or finding the best estimation of surgical case durations. The other solution is to construct an effective surgical case plan and schedule. The operating theatre planning and scheduling is the two important steps, which aim to make a surgical case programming with an objective of obtaining a realizable and efficient surgical case schedule. This paper focuses on the first step, the operating theatre planning problem. Two planning methods are introduced and compared. Real data of a Belgian university hospital "Tivoli" are used for the experiments. 相似文献
208.
An improved branch-and-bound algorithm to minimize the weighted flowtime on identical parallel machines with family setup times 总被引:1,自引:0,他引:1
Belgacem BETTAYEB Imed KACEM Kondo H.ADJALLAH LOSI-ICD CNRS FRE Universitéde technologie de Troyes France 《系统科学与系统工程学报(英文版)》2008,17(4):446-459
This article investigates identical parallel machines scheduling with family setup times. The objective function being the weighted sum of completion times, the problem is known to be strongly NP-hard. We propose a constructive heuristic algorithm and three complementary lower bounds. Two of these bounds proceed by elimination of setup times or by distributing each of them to jobs of the corresponding family, while the third one is based on a lagrangian relaxation. The bounds and the heuristic are incorporated into a branch-and-bound algorithm. Experimental results obtained outperform those of the methods presented in previous works, in term of size of solved problems. 相似文献
209.
210.
Benharrat BELAIDI 《系统科学与复杂性》2007,20(1):41-46
In this paper, we investigate the growth of meromorphic solutions of higher order linear differential equation f^(k) +Ak-1 (z)e^Pk-1^(z) f^(k-1) +…+A1 (z)e^P1(z) f′ +Ao(z)e^Po(z) f = 0 (k ≤ 2), where Pj(z) (j = 0, 1,..., k - 1) are nonconstant polynomials such that deg Pj = n (j = 0, 1,..., k - 1) and Aj(z)(≠ 0) (j = 0, 1,..., k - 1) are meromorphic functions with order p(Aj) 〈 n (j = 0, 1,..., k - 1). 相似文献