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Selected AbstractsContiguity Constraints for Single-Region Site Search ProblemsGEOGRAPHICAL ANALYSIS, Issue 4 2000Thomas J. Cova This paper proposes an explicit set of constraints as a general approach to the contiguity problem in site search modeling. Site search models address the challenging problem of identifying the best area in a study region for a particular land use, given that there are no candidate sites. Criteria that commonly arise in a search include a site's area, suitability, cost, shape, and proximity to surrounding geographic features. An unsolved problem in this modeling arena is the identification of a general set of mathematical programming constraints that can guarantee a contiguous solution (site) for any 0,1 integer-programming site search formulation. The constraints proposed herein address this problem, and we evaluate their efficacy and efficiency in the context of a regular and irregular tessellation of geographic space. An especially efficient constraint form is derived from a more general form and similarly evaluated. The results demonstrate that the proposed constraints represent a viable, general approach to the contiguity problem. [source] Rendezvous search when marks are left at the starting pointsNAVAL RESEARCH LOGISTICS: AN INTERNATIONAL JOURNAL, Issue 8 2001Vic Baston Abstract Leaving marks at the starting points in a rendezvous search problem may provide the players with important information. Many of the standard rendezvous search problems are investigated under this new framework which we call markstart rendezvous search. Somewhat surprisingly, the relative difficulties of analysing problems in the two scenarios differ from problem to problem. Symmetric rendezvous on the line seems to be more tractable in the new setting whereas asymmetric rendezvous on the line when the initial distance is chosen by means of a convex distribution appears easier to analyse in the original setting. Results are also obtained for markstart rendezvous on complete graphs and on the line when the players' initial distance is given by an unknown probability distribution. © 2001 John Wiley & Sons, Inc. Naval Research Logistics 48: 722,731, 2001 [source] Optimal search on spatial paths with recall, Part II: Computational procedures and examplesPAPERS IN REGIONAL SCIENCE, Issue 3 2000Mitchell Harwitz Search; spatial search; spatial economics Abstract. This is the second part of a two-part analysis of optimal spatial search begun in Harwitz et al. (1998). In the present article, two explicit computational procedures are developed for the optimal spatial search problem studied in Part I. The first uses reservation prices with continuous known distributions of prices and is illustrated for three stores. The second does not use reservation prices but assumes known discrete distributions. It is a numerical approximation to the first and also a tool for examining examples with larger numbers of stores. [source] Dynamic optimization of N -joint robotic limb deploymentsJOURNAL OF FIELD ROBOTICS (FORMERLY JOURNAL OF ROBOTIC SYSTEMS), Issue 3 2010Wolfgang Fink We describe an approach using a stochastic optimization framework (SOF) for operating complex mobile systems with several degrees of freedom (DOFs), such as robotic limbs with N joints, in environments that can contain obstacles. As part of the SOF, we have employed an efficient simulated annealing algorithm normally used in computationally highly expensive optimization and search problems such as the traveling salesman problem and protein design. This algorithm is particularly suited to run onboard industrial robots, robots in telemedicine, remote spacecraft, planetary landers, and rovers, i.e., robotic platforms with limited computational capabilities. The robotic limb deployment optimization approach presented here offers an alternative to time-intensive robotic arm deployment path planning algorithms in general and in particular for robotic limb systems in which closed-form solutions do not exist. Application examples for a (N = 4)-DOF arm on a planetary exploration rover are presented. © 2009 Wiley Periodicals, Inc. [source] Rendezvous search when marks are left at the starting pointsNAVAL RESEARCH LOGISTICS: AN INTERNATIONAL JOURNAL, Issue 8 2001Vic Baston Abstract Leaving marks at the starting points in a rendezvous search problem may provide the players with important information. Many of the standard rendezvous search problems are investigated under this new framework which we call markstart rendezvous search. Somewhat surprisingly, the relative difficulties of analysing problems in the two scenarios differ from problem to problem. Symmetric rendezvous on the line seems to be more tractable in the new setting whereas asymmetric rendezvous on the line when the initial distance is chosen by means of a convex distribution appears easier to analyse in the original setting. Results are also obtained for markstart rendezvous on complete graphs and on the line when the players' initial distance is given by an unknown probability distribution. © 2001 John Wiley & Sons, Inc. Naval Research Logistics 48: 722,731, 2001 [source] |