1,875 research outputs found
Current Approaches to Improving the Value of Care: A Physician's Perspective
Evaluates the utility of judgment-based approaches to quality improvement -- pay-for-performance, public reporting, consumer-directed health plans, and tiering -- as ways to control costs. Recommends incentive- and accountability-based programs
Basin tillage for erosion control
A three-unit basin tillage machine which mechanically formed earthen dams in the tilled soil of bedded row middles was designed, constructed, and field tested. The objectives of the test were to evaluate the operation of the machine and to evaluate the effective-ness of diked bedded row middles in controlling soil loss by water erosion. Diked and undiked treatments were compared during six tests using slopes of 2 and 5 percent and slope lengths of 65 feet and 50 feet, respectively. A test consisted of subjecting two plots, one diked and the other undiked on the same ground slope and of the same slope length, to simulated rainfall of a given intensity. Rainfall application intensities ranged from 0.68 to 4.89 inches per hour. Runoff samples from each plot were manually collected at 4-minute intervals from type HS flumes installed at each plot outlet. Runoff rates were determined by measuring the depths of flow in the flumes, Sediment concentrations in the runoff water samples were determined by laboratory analyses and subsequently translated to mass of soil loss. The prototype machine operated relatively trouble-free under typical field conditions throughout the experiment. Diked plots, when compared to undiked plots, generally exhibited lower runoff rates, contained less sediment in the runoff water, and allowed more water to infiltrate the soil
Online choosability of graphs
We study several problems in graph coloring. In list coloring, each vertex has a set of available colors and must be assigned a color from this set so that adjacent vertices receive distinct colors; such a coloring is an -coloring, and we then say that is -colorable. Given a graph and a function , we say that is -choosable if is -colorable for any list assignment such that for all . When for all and is -choosable, we say that is -choosable. The least such that is -choosable is the choice number, denoted . We focus on an online version of this problem, which is modeled by the Lister/Painter game.
The game is played on a graph in which every vertex has a positive number of tokens. In each round, Lister marks a nonempty subset of uncolored vertices, removing one token at each marked vertex. Painter responds by selecting a subset of that forms an independent set in . A color distinct from those used on previous rounds is given to all vertices in . Lister wins by marking a vertex that has no tokens, and Painter wins by coloring all vertices in . When Painter has a winning strategy, we say that is -paintable. If for all and is -paintable, then we say that is -paintable. The least such that is -paintable is the paint number, denoted \pa(G).
In Chapter 2, we develop useful tools for studying the Lister/Painter game. We study the paintability of graph joins and of complete bipartite graphs. In particular, \pa(K_{k,r})\le k if and only if .
In Chapter 3, we study the Lister/Painter game with the added restriction that the proper coloring produced by Painter must also satisfy some property . The main result of Chapter 3 provides a general method to give a winning strategy for Painter when a strategy for the list coloring problem is already known. One example of a property is that of having an -dynamic coloring, where a proper coloring is -dynamic if each vertex has at least distinct colors in its neighborhood. For any graph and any , we give upper bounds on how many tokens are necessary for Painter to produce an -dynamic coloring of . The upper bounds are in terms of and the genus of a surface on which embeds.
In Chapter 4, we study a version of the Lister/Painter game in which Painter must assign colors to each vertex so that adjacent vertices receive disjoint color sets. We characterize the graphs in which tokens is sufficient to produce such a coloring. We strengthen Brooks' Theorem as well as Thomassen's result that planar graphs are 5-choosable.
In Chapter 5, we study sum-paintability. The sum-paint number of a graph , denoted \spa(G), is the least over all such that is -paintable. We prove the easy upper bound: \spa(G)\le|V(G)|+|E(G)|. When \spa(G)=|V(G)|+|E(G)|, we say that is sp-greedy. We determine the sum-paintability of generalized theta-graphs. The generalized theta-graph consists of two vertices joined by paths of lengths \VEC \ell1k. We conjecture that outerplanar graphs are sp-greedy and prove several partial results toward this conjecture.
In Chapter 6, we study what happens when Painter is allowed to allocate tokens as Lister marks vertices. The slow-coloring game is played by Lister and Painter on a graph . Lister marks a nonempty set of uncolored vertices and scores 1 point for each marked vertex. Painter colors all vertices in an independent subset of the marked vertices with a color distinct from those used previously in the game. The game ends when all vertices have been colored. The sum-color cost of a graph , denoted \scc(G), is the maximum score Lister can guarantee in the slow-coloring game on . We prove several general lower and upper bounds for \scc(G). In more detail, we study trees and prove sharp upper and lower bounds over all trees with vertices. We give a formula to determine \scc(G) exactly when . Separately, we prove that \scc(G)=\spa(G) if and only if is a disjoint union of cliques. Lastly, we give lower and upper bounds on \scc(K_{r,s})
Rhodium/phospholane-phosphite catalysts give unusually high regioselectivity in the enantioselective hydroformylation of vinyl arenes
Using the phospholane-phosphite ligand, BOBPHOS, almost perfect regioselectivities and high enantioselectivities (up to 92% ee) are observed in Rh catalysed enantioselective hydroformylation of vinyl arenes. This can be achieved under solvent-free conditions.PostprintPeer reviewe
Ensuring American Manufacturing Leadership Through Next-Generation Supply Chains
Suppliers now account for 50-70 percent of a typical manufacturerâs final production value. How U.S. manufacturers manage their supply chains has been the key to offshoring production and will be the key to rebuilding a robust manufacturing sector. Traditional purchasing practices, in which buying decisions are based on the lowest unit cost with acceptable quality and delivery, drove much of the shift to Asian suppliers. As Asian capabilities progressed, a more diverse range of products were imported from Asia, mostly China. Some U.S. suppliers responded by building production facilities or contracting production in China, while others, unable to compete, failed. The number of U.S. manufacturing establishments, 292,825 in 2015, has declined by more than 41,000 since 2005.
A growing number of U.S. manufacturers, however, have recognized that this model of supply chain management does not provide a sustainable competitive advantage. If their products are made in the same factories as those of their competitors, product differentiation too often has become superficial. Regaining a competitive edge requires a different approach to managing suppliers, one in which the total supply chain is managed to maximize value. Suppliers are treated as partners, contributing design and engineering ideas. Manufacturing capacity, production planning, and delivery schedules are closely coordinated. Rather than a strict focus on low unit price, broader considerations of cost, flexibility, consistency, and risk minimizationâcollectively known as Total Cost of Ownershipâdrives purchasing decisions, at least for high-value parts and components. Many specific tools and techniques for building strong supplier partnerships have been created, and could be more widely used with appropriate training and information sharing.National Science Foundation, Grant No. 1552534https://deepblue.lib.umich.edu/bitstream/2027.42/145153/1/SupplyChainReport_Digital_FINAL_reduced.pdfDescription of SupplyChainReport_Digital_FINAL_reduced.pdf : Repor
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