188,802 research outputs found
The interval ordering problem
For a given set of intervals on the real line, we consider the problem of
ordering the intervals with the goal of minimizing an objective function that
depends on the exposed interval pieces (that is, the pieces that are not
covered by earlier intervals in the ordering). This problem is motivated by an
application in molecular biology that concerns the determination of the
structure of the backbone of a protein.
We present polynomial-time algorithms for several natural special cases of
the problem that cover the situation where the interval boundaries are
agreeably ordered and the situation where the interval set is laminar. Also the
bottleneck variant of the problem is shown to be solvable in polynomial time.
Finally we prove that the general problem is NP-hard, and that the existence of
a constant-factor-approximation algorithm is unlikely
Frequentist Hypothesis Testing with Background Uncertainty
We consider the standard Neyman-Pearson hypothesis test of a
signal-plus-background hypothesis and background-only hypothesis in the
presence of uncertainty on the background-only prediction. Surprisingly, this
problem has not been addressed in the recent conferences on statistical
techniques in high-energy physics -- although the its confidence-interval
equivalent has been. We discuss the issues of power, similar tests, coverage,
and ordering rules. The method presented is compared to the Cousins-Highland
technique, the ratio of Poisson means, and ``profile'' method.Comment: Talk from PhyStat2003, Stanford, Ca, USA, September 2003, 4 pages,
LaTeX, 2 eps figures. PSN WEMT00
On the Economic Order Quantity Model With Transportation Costs
We consider an economic order quantity type model with unit out-of-pocket holding costs, unitopportunity costs of holding, fixed ordering costs and general transportation costs. For these models, we analyzethe associated optimization problem and derive an easy procedure for determining a bounded interval containingthe optimal cycle length. Also for a special class of transportation functions, like the carload discount schedule, wespecialize these results and give fast and easy algorithms to calculate the optimal lot size and the correspondingoptimal order-up-to-level.EOQ-type model;exact solution;transportation cost function;upper bounds
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