Ground water level monitoring at Yucca Mountain — A programmatic summary

Scope - Confirmatory study supporting previously gathered information - Measure levels on established network of monitoring wells - Submit data annually Objectives - Provide measurements of known accuracy and precision - Use manual and electronic equipment - Provide quality assured data - Contribute to hydrological understanding - Support refinement of potentiometric surface - Provide data for regional flow model - Fulfill State of Nevada permit conditions - Monitor transient events such as seismically induced fluctuations and precipitation-related phenomena - Support long term monitoring and trend analysis - Support proposed repository licensing applicatio

On the Emergence of Cities

This paper considers the formation of cities in a simple model in which the preferences of agents depend on at most two characteristics of a location: its population and its average distance to the other agents. In such a simple model it is possible to recreate phenomena such as path dependency and centrally located cities which have been generated in more sophisticated models. Moreover, an example is provided in which cities emerge in the sense that the micro level preferences of agents do not appear to favor locating near or with other agents. When nonlinear effects are included then it is possible to show that even if efficient equilibria exist, they are not likely to occur and that there may exist extreme sensitivity to initial conditions. The model suggests that the mapping from individual preferences to population distributions merits further study

A Bottom-Up Efficient Algorithm for Allocating Public Projects with Positive Complementarities

In this paper, we consider the problem of locating an optimal package of public projects from a set of potential projects when the public projects have positive complementarities. We formulate the problem as a discrete nonlinear optimization problem whose domain equals the power set of a finite collection of projects. The main contribution of this paper is the construction of an efficient algorithm, among the set of bottom-up algorithms, for projects with positive and positive uniform complementarities. The restriction to bottom-up algorithms sterns from practical considerations discussed in the paper. We also discuss shortcomings of three natural approaches to addressing the problem: exhaustive search over packages, simultaneous evaluation of projects, and sequential evaluation of projects

Covers

This paper introduces the theory of covers for functions defined over binary variables. Covers formalize the notion of decomposability. Large complex problems are decomposed into subproblems each containing fewer variables, which can then be solved in parallel. Practical applications of the benefits from decomposition include the parallel architecture of supercomputers, the divisionalization of firms, and the decentralization of economic activity. In this introductory paper, we show how covers also shed light on the choice among public projects with complementarities. Further, covers provide a measure of complexity/decomposability with respect to contour sets, allowing for nonlinear effects which occur near the optimum to receive more weight than nonlinear effects arbitrarily located in the domain. Finally, as we demonstrate, covers can be used to analyze and to calibrate search algorithms

Multiple-objective sensor management and optimisation

One of the key challenges associated with exploiting modern Autonomous Vehicle technology for military surveillance tasks is the development of Sensor Management strategies which maximise the performance of the on-board Data-Fusion systems. The focus of this thesis is the development of Sensor Management algorithms which aim to optimise target tracking processes. Three principal theoretical and analytical contributions are presented which are related to the manner in which such problems are formulated and subsequently solved.Firstly, the trade-offs between optimising target tracking and other system-level objectives relating to expected operating lifetime are explored in an autonomous ground sensor scenario. This is achieved by modelling the observer trajectory control design as a probabilistic, information-theoretic, multiple-objective optimisation problem. This novel approach explores the relationships between the changes in sensor-target geometry that are induced by tracking performance measures and those relating to power consumption. This culminates in a novel observer trajectory control algorithm based onthe minimax approach.The second contribution is an analysis of the propagation of error through a limited-lookahead sensor control feedback loop. In the last decade, it has been shown that the use of such non-myopic (multiple-step) planning strategies can lead to superior performance in many Sensor Management scenarios. However, relatively little is known about the performance of strategies which use different horizon lengths. It is shown that, in the general case, planning performance is a function of the length of the horizon over which the optimisation is performed. While increasing the horizon maximises the chances of achieving global optimality, by revealing information about the substructureof the decision space, it also increases the impact of any prediction error, approximations, or unforeseen risk present within the scenario. These competing mechanisms aredemonstrated using an example tracking problem. This provides the motivation for a novel sensor control methodology that employs an adaptive length optimisation horizon. A route to selecting the optimal horizon size is proposed, based on a new non-myopic risk equilibrium which identifies the point where the two competing mechanisms are balanced.The third area of contribution concerns the development of a number of novel optimisation algorithms aimed at solving the resulting sequential decision making problems. These problems are typically solved using stochastic search methods such as Genetic Algorithms or Simulated Annealing. The techniques presented in this thesis are extensions of the recently proposed Repeated Weighted Boosting Search algorithm. In its originalform, it is only applicable to continuous, single-objective, ptimisation problems. The extensions facilitate application to mixed search spaces and Pareto multiple-objective problems. The resulting algorithms have performance comparable with Genetic Algorithm variants, and offer a number of advantages such as ease of implementation and limited tuning requirements

Making Old Things New Again: The Northridge Psalter, with Antiphons Based on Lessons from the Revised Common Lectionary

Responsive psalmody is one of the primary musical vehicles for presenting the Psalms in worship by choir and congregation. Existing responsive psalmody features congregational antiphons with texts derived directly from the psalms. Working with the Revised Common Lectionary, this thesis presents fifty newly written and composed antiphons with texts derived from the accompanying RCL lessons. The goal of this method is to emphasize prophetic connections between the Old Testament lesson and Gospel lesson via the antiphons. This thesis also features a history of lectionary development, a detailed account of the creative process, rubrics for presenting the responsive psalmody in worship, musical-theological analysis, and psalm reflections

Circulation and Sediment Dispersal on the Louisiana-Mississippi-Alabama Continental Shelf.

The circulation on the LMAS and adjacent regions has been characterized using historical hydrographic data and current meter data. Generalized seasonal circulation patterns have been proposed based on objective data over the inner shelf, outer shelf, and upper slope. Hydrographic data, acquired from the National Oceanographic Data Center, covering the Louisiana-Mississippi-Alabama shelf (LMAS) and slope was analyzed. Seasonal maps of dynamic heights, relative to 500 db, were computed. Inner shelf current data, acquired from the U.S. Army Corps of Engineers, was analyzed. Three current meter deployments (winter 1980, spring 1981, summer 1981) with up to eight mooring locations, along with coastal winds, were subject to complex spectral analyses, complex empirical orthogonal function analyses, and momentum balance analyses. Westward flows on the inner shelf, outer shelf and upper slope in the spring and summer are interpreted as the northern and southern portions of closed cyclonic and anticyclonic circulation cells, respectively. Spring and summer midshelf flow is eastward, with offshelf flow over the eastern LMAS shelf break. Upper slope flow continues on westward in front of the Mississippi Delta, while outer shelf flow turns northward onto the shelf just east of the Delta. These two circulating cells are assumed to continue in the fall. Flow in front of the Delta is to east in fall and winter. Winter shelf circulation appears to consist of a single cyclonic cell. There is weak offshelf flow all along the shelf-break in winter. Wave-induced sediment resuspension and advection by subtidal bottom currents are both necessary for net sediment transport on the inner shelf. Long-term hindcast wave statistics for the LMAS, acquired from the U.S Army Corps of Engineers, were analyzed. Sediment resuspension during high wave conditions can occur in water depths of 40 m or less. Highest wave conditions, with durations on the order of hours per year, may resuspension sediment in up to 80 m water depth. Sediment transport occurs primarily during prefrontal winds conducive to long waves and cyclonic inner shelf flow in the winter and spring. Outer shelf and upper slope sediments are most likely to be resuspended only by hurricane condition waves or, possibly, by direct influence of the Loop Current

Optimal team composition for tool‐based problem solving

In this paper, we construct a framework for modeling teams of agents who apply techniques or procedures (tools) to solve problems. In our framework, tools differ in their likelihood of solving the problem at hand; agents, who may be of different types, vary in their skill at using tools. We establish baseline hiring rules when a manager can dictate tool choice and then derive results for strategic tool choice by team members. We highlight three main findings: First, that cognitively diverse teams are more likely to solve problems in both settings. Second, that teams consisting of types that master diverse tools have an indirect strategic advantage because tool diversity facilitates coordination. Third, that strategic tool choice creates counterintuitive optimal hiring practices. For example, optimal teams may exclude the highest ability types and can include dominated types. In addition, optimal groups need not increase setwise. Our framework extends to cover teamwork on decomposable problems, to cases where individuals apply multiple tools, and to teams facing a flow or set of problems.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/152035/1/jems12295.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/152035/2/jems12295_am.pd

First mover or higher quality? Optimal product strategy in markets with positive feedbacks

Conventional wisdom holds that in markets with positive feedbacks being first to market can matter more than product quality. In this paper, we test that intuition within a generalized Pólya urn model. We find that if we assume constant feedbacks, in the long run, higher quality products dominate the market regardless of initial market shares, contradicting the common wisdom. However, when we allow for variable feedbacks, initial advantages persist almost indefinitely. Thus, the choice of whether to rush to market or focus on quality depends on market characteristics such as whether the positive feedbacks result from more consistent returns to scale or from more variable social influences.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/142337/1/jems12231-sup-0001-OnlineAppendix.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/142337/2/jems12231_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/142337/3/jems12231.pd