2,966 research outputs found

    Heuristics for Sparsest Cut Approximations in Network Flow Applications

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    The Maximum Concurrent Flow Problem (MCFP) is a polynomially bounded problem that has been used over the years in a variety of applications. Sometimes it is used to attempt to find the Sparsest Cut, an NP-hard problem, and other times to find communities in Social Network Analysis (SNA) in its hierarchical formulation, the HMCFP. Though it is polynomially bounded, the MCFP quickly grows in space utilization, rendering it useful on only small problems. When it was defined, only a few hundred nodes could be solved, where a few decades later, graphs of one to two thousand nodes can still be too much for modern commodity hardware to handle. This dissertation covers three approaches to heuristics to the MCFP that run significantly faster in practice than the LP formulation with far less memory utilization. The first two approaches are based on the Maximum Adjacency Search (MAS) and apply to both the MCFP and the HMCFP used for community detection. We compare the three approaches to the LP performance in terms of accuracy, runtime, and memory utilization on several classes of synthetic graphs representing potential real-world applications. We find that the heuristics are often correct, and run using orders of magnitude less memory and time

    Profiles of learning. The Basic Skills Testing Program in New South Wales 1989

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    The 1989 Basic Skills Testing Program in New South Wales provides the most comprehensive picture yet compiled of literacy and numeracy learning in Australian primary schools. In 1989, some 53,800 Year 6 students in NSW government schools were tested in five aspects of literacy and numeracy. Another 2,300 Year 3 students took part in a pilot study. This book discusses the writing of the tests, the analysis of results, and the reporting of results to parents, teachers and schools. The aim of the basic skills tests is to describe, in positive terms, the skills that students have mastered, to identify areas in which students have special strengths and weaknesses, and to provide guides to further learning. The picture that emerges from this study is of widespread success in learning. The results point to much good teaching and a fine start in learning for most primary students. But this generally optimistic picture is over shadowed by the performances of some students who have not yet mastered essential Year 6 skills. Part I of the book describes the skills typical of students performing at each of five skill levels in each of five areas of learning (Reading, Language, Number, Measurement, and Space) on the tests. Part II shows how different subgroups of students performed on the tests. Results on each aspect of literacy and numeracy are reported separately for girls and boys, students with non-English-speaking backgrounds, Aboriginal and Torres Strait Islander students, and several age groupings. Part III explains and gives examples of reports mailed to parents, more detailed reports given to teachers, and summary tables generated for each school. Part IV describes procedures used to develop BSTP tests and to analyze students\u27 results in preparation for reporting. Numerous test items are presented

    Archeological Investigations for the Levi Jordan Plantation House Stabilization, Brazoria County, Texas

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    The Levi Jordan plantation house is one of the few antebellum plantation structures to have survived in Brazoria County. It is the only standing structure associated with the plantation, which began operating in 1848 and was occupied continually up through the 1990s. The original house, built in the early 1850s using slave labor, was a 20x60-ft two-story wooden frame structure. It was altered many times during its long occupation, often due to hurricane damage. A portion of the Levi Jordan Plantation was acquired by the State of Texas in 2002 and managed by the Texas Parks and Wildlife Department until 2008, when the Texas Historical Commission took over its management. By then, the 160-year-old plantation house had suffered greatly and was in bad condition. The Texas Historical Commission began plans to stabilize and restore the historic house. Prewitt and Associates archeologists were contracted to conduct the archeological investigations associated with this work. The stabilization project included the permanent removal of the twentieth-century additions, hydraulic lifting of the antebellum house, removal of the original foundation piers, and installation of a new concrete perimeter foundation. The two original brick chimneys were removed and reconstructed. The investigations, conducted in 2010 and 2011, documented the following features: 2 cisterns, 2 chimney footings and 39 foundation piers associated with the plantation house; a chimney footing associated with an east wing behind the house; a chimney foundation associated with a former detached kitchen behind the main house; a brick patio and walkway associated with the original house; two large brick rubble concentrations and a small brick cluster; and a possible rain barrel brick pad. Other features examined were 15 possible piers that may be associated with the original house, the original east wing, a possible west wing, a south porch, a west porch, and an east porch. The archeological investigations revealed many details about the architecture of the original plantation house and subsequent additions. The evidence provides a better understanding of the building construction sequence and insights into the complex evolution of the Levi Jordan plantation house over its ca. 160-year existence. The most significant find is an 1853 gold coin found in the brick pad at the bottom of the southeast corner pier. This is almost certainly a date coin that was placed in this location by Levi Jordan or a master builder in a cornerstone foundation rite, and it provides an accurate date for the beginning of the house construction

    Flawed Thinking: Addressing Decision Biases in Negotiation

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    Published in cooperation with the American Bar Association Section of Dispute Resolutio
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