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Reasonable Conditions (reasonable + condition)
Selected AbstractsReview of the Integrated Groundwater and Surface-Water Model (IGSM)GROUND WATER, Issue 2 2003Eric M. LaBolle Development of the finite-element-based Integrated Groundwater and Surface-Water Model (IGSM) began in the 1970s. Its popularity grew in the early 1990s with its application to California's Central Valley Groundwater Surface-Water Model in support of the Central Valley Project Improvement Act. Since that time, IGSM has been applied by federal, state, and local agencies to model a number of major basins in California. Our review of the recently released version 5.0 of IGSM reveals a solution methodology that deviates from established solution techniques, potentially compromising its reliability under many circumstances. One difficulty occurs because of the semi-explicit time discretization used. Combined with the fixed monthly time step of IGSM, this approach can prevent applications from accurately converging when using parameter values typically found in nature. Additionally, IGSM fails to properly couple and simultaneously solve ground water and surface water models with appropriate mass balance and head convergence under the reasonable conditions considered herein. As a result, IGSM-predicted streamflow is error prone, and errors could exceed 100%. IGSM does not inform the user that there may be a convergence problem with the solution, but instead generally reports good mass balance. Although our review touches on only a few aspects of the code, which exceeds 17,000 lines, our experience is that similar problems arise in other parts of IGSM. Review and examples demonstrate the potential consequences of using the solution methods in IGSM for the prediction, planning, and management of water resources, and provide perspective on the roles of standards and code validation in ground water modeling. [source] Decision making beyond arrow's "impossibility theorem," with the analysis of effects of collusion and mutual attractionINTERNATIONAL JOURNAL OF INTELLIGENT SYSTEMS, Issue 1 2009Hung T. Nguyen In 1951, K.J. Arrow proved that, under certain assumptions, it is impossible to have group decision-making rules that satisfy reasonable conditions like symmetry. This Impossibility Theorem is often cited as a proof that reasonable group decision-making is impossible. We start our article by remarking that Arrow's result covers only those situations when the only information we have about individual preferences is their binary preferences between the alternatives. If we follow the main ideas of modern decision making and game theory and also collect information about the preferences between lotteries (i.e., collect the utility values of different alternatives), then reasonable decision-making rules are possible, e.g., Nash's rule in which we select an alternative for which the product of utilities is the largest possible. We also deal with two related issues: how we can detect individual preferences if all we have is preferences of a subgroup and how we take into account the mutual attraction between participants. © 2008 Wiley Periodicals, Inc. [source] Polyhedral studies for minimum-span graph labelling with integer distance constraintsINTERNATIONAL TRANSACTIONS IN OPERATIONAL RESEARCH, Issue 2 2007Vicky Mak Abstract This paper studies the polytope of the minimum-span graph labelling problems with integer distance constraints (DC-MSGL). We first introduce a few classes of new valid inequalities for the DC-MSGL defined on general graphs and briefly discuss the separation problems of some of these inequalities. These are the initial steps of a branch-and-cut algorithm for solving the DC-MSGL. Following that, we present our polyhedral results on the dimension of the DC-MSGL polytope, and that some of the inequalities are facet defining, under reasonable conditions, for the polytope of the DC-MSGL on triangular graphs. [source] A Bayesian predictive analysis of test scoresJAPANESE PSYCHOLOGICAL RESEARCH, Issue 1 2001Hidetoki Ishii In the classical test theory, a high-reliability test always leads to a precise measurement. However, when it comes to the prediction of test scores, it is not necessarily so. Based on a Bayesian statistical approach, we predicted the distributions of test scores for a new subject, a new test, and a new subject taking a new test. Under some reasonable conditions, the predicted means, variances, and covariances of predicted scores were obtained and investigated. We found that high test reliability did not necessarily lead to small variances or covariances. For a new subject, higher test reliability led to larger predicted variances and covariances, because high test reliability enabled a more accurate prediction of test score variances. Regarding a new subject taking a new test, in this study, higher test reliability led to a large variance when the sample size was smaller than half the number of tests. The classical test theory is reanalyzed from the viewpoint of predictions and some suggestions are made. [source] Averaging probability judgments: Monte Carlo analyses of asymptotic diagnostic valueJOURNAL OF BEHAVIORAL DECISION MAKING, Issue 2 2001Timothy R. Johnson Abstract Wallsten et al. (1997) developed a general framework for assessing the quality of aggregated probability judgments. Within this framework they presented a theorem regarding the effects of pooling multiple probability judgments regarding unique binary events. The theorem states that under reasonable conditions, and assuming conditional pairwise independence of the judgments, the average probability estimate is asymptotically perfectly diagnostic of the true event state as the number of estimates pooled goes to infinity. The purpose of the present study was to examine by simulation (1) the rate of convergence of averaged judgments to perfect diagnostic value under various conditions and (2) the robustness of the theorem to violations of its assumption that the covert probability judgments are conditionally pairwise independent. The results suggest that while the rate of convergence is sensitive to violations of the conditional pairwise independence, the asymptotic properties remain relatively robust under a large variety of conditions. The practical implications of these results are discussed. Copyright © 2001 John Wiley & Sons, Ltd. [source] Fixed Wages and Bonuses in Agency Contracts: The Case of a Continuous State SpaceJOURNAL OF PUBLIC ECONOMIC THEORY, Issue 5 2006MARIA RACIONERO In this paper, we extend the state-contingent production approach to principal,agent problems to the case where the state space is an atomless continuum. The approach is modelled on the treatment of optimal tax problems. The central observation is that, under reasonable conditions, the optimal contract may involve a fixed wage with a bonus for above-normal performance. This is analogous to the phenomenon of "bunching" at the bottom in the optimal tax literature. [source] A trust-region method with a conic model for unconstrained optimizationMATHEMATICAL METHODS IN THE APPLIED SCIENCES, Issue 15 2008Shao-Jian Qu Abstract In this paper, we propose and analyze a new conic trust-region algorithm for solving the unconstrained optimization problems. A new strategy is proposed to construct the conic model and the relevant conic trust-region subproblems are solved by an approximate solution method. This approximate solution method is not only easy to implement but also preserves the strong convergence properties of the exact solution methods. Under reasonable conditions, the locally linear and superlinear convergence of the proposed algorithm is established. The numerical experiments show that this algorithm is both feasible and efficient. Copyright © 2008 John Wiley & Sons, Ltd. [source] Dynamic-spatial management of coastal aquifersOPTIMAL CONTROL APPLICATIONS AND METHODS, Issue 1 2010Iddo Kan Abstract We analyze the management of a coastal aquifer under seawater intrusion (SWI) using distributed control methods. The aquifer's state is taken as the water head elevation (vis-à-vis sea level, say), which varies with time and in space since extraction, natural recharge and lateral water flows vary with time and in space. The water head, in turn, induces a temporal-spatial SWI process, which changes the volume of fresh water in the aquifer. Under reasonable conditions we show that the optimal state converges to a steady-state process that is constant in time. We characterize the optimal steady-state process in terms of a standard control problem (in space) and offer a tractable algorithm to solve for it. Copyright © 2009 John Wiley & Sons, Ltd. [source] Determination of a controllable set for a class of non-linear stochastic control systemsOPTIMAL CONTROL APPLICATIONS AND METHODS, Issue 3 2003Yazeng Liu Abstract A controllable set of a class of non-linear stochastic control systems to a given set is defined. A value function associated with an optimal control problem is introduced. Under some reasonable conditions, the controllable set is characterized by a level set of the viscosity solution of a Hamilton,Jacobi,Bellman equation. Copyright © 2003 John Wiley & Sons, Ltd. [source] Moving boundary vortices for a thin-film limit in micromagneticsCOMMUNICATIONS ON PURE & APPLIED MATHEMATICS, Issue 5 2005Roger Moser We study the limiting behavior of solutions of the Landau-Lifshitz-Gilbert equation belonging to thin films of ferromagnetic materials. In the appropriate time scale and under reasonable conditions, there is a subsequence converging to a map that has vortices at two boundary points. The vortices move Hölder-continuously in time, and the map satisfies a formal Euler-Lagrange equation away from the vortices. © 2004 Wiley Periodicals, Inc. [source] | ||||||||||||||||