42 research outputs found
PMLB: A Large Benchmark Suite for Machine Learning Evaluation and Comparison
The selection, development, or comparison of machine learning methods in data
mining can be a difficult task based on the target problem and goals of a
particular study. Numerous publicly available real-world and simulated
benchmark datasets have emerged from different sources, but their organization
and adoption as standards have been inconsistent. As such, selecting and
curating specific benchmarks remains an unnecessary burden on machine learning
practitioners and data scientists. The present study introduces an accessible,
curated, and developing public benchmark resource to facilitate identification
of the strengths and weaknesses of different machine learning methodologies. We
compare meta-features among the current set of benchmark datasets in this
resource to characterize the diversity of available data. Finally, we apply a
number of established machine learning methods to the entire benchmark suite
and analyze how datasets and algorithms cluster in terms of performance. This
work is an important first step towards understanding the limitations of
popular benchmarking suites and developing a resource that connects existing
benchmarking standards to more diverse and efficient standards in the future.Comment: 14 pages, 5 figures, submitted for review to JML
Alkali metal derivatives of an ortho-phenylene diamine
Treatment of the ortho-phenylene diamine C6H4-1,2-{N(H)Tripp}2 (1, PDAH2, Tripp = 2,4,6-triisopropylphenyl) with two equivalents of MR (M = Li, R = Bun; M = Na or K, R = CH2C6H5) afforded the dimetallated alkali metal ortho-phenylene diamide dianion complexes [(PDALi2)(THF)3] (2), [{(PDANa2)(THF)2}2] (3), and [{(PDAK2)(THF)3}2] (4). In contrast, treatment of 2 with two equivalents of rubidium or cesium 2-ethylhexoxide, or treatment of 1 with two equivalents of MR (M = Rb or Cs, R = CH2C6H5) did not afford the anticipated dialkali metal ortho-phenylene diamide dianion derivatives and instead formally afforded the monometallic ortho-diiminosemiquinonate radical anion species [PDAM] (M = Rb, 5; M = Cs, 6). The structure of 2 is monomeric with one lithium coordinated to the two nitrogen centres and the other lithium η4-coordinated to the diazabutadiene portion of the PDA scaffold. Similar structural cores are observed for 3 and 4, except that the larger sodium and potassium ions give dimeric structures linked by multi-hapto interactions from the PDA backbone phenyl ring to an alkali metal centre. Complex 5 was not characterised in the solid state, but the structure of 6 reveals coordination of cesium ions to both PDA amide centres and multi-hapto interactions to a PDA backbone phenyl ring in the next unit to generate a one-dimensional polymer. Complexes 2–6 have been variously characterised by X-ray crystallography, multi-nuclear NMR, FTIR, and EPR spectroscopies, and CHN microanalyses
Public Sector Unions and Public Spending
This study examines the influence of public sector unions on the expansion of the public sector. Based on public goods theory, our paper models how unions influence the supply of and demand for public sector activities. On the demand side, public sector unions are special interests which advocate public sector expansion to policy makers; on the supply side, they exert pressure to maintain and expand monopoly powers. Empirical evidence supports the hypothesis that a positive relationship exists between public sector unionism and public spending
The Separation of Spending from Taxation: Implications for Collective Choices
Our fiscal process divorces payment from use. While this divorce has led many analysts of government to separate discussion of public expenditures from their funding, or use from payment, we argue that this approach does not provide a useful framework for understanding our public choices. We argue that it is the divorce of payment from use that underlies our fiscal process and, rather than simply \u27dismiss out of hand \u27 study of our fiscal process, it should be an integral part of our study of government. Our framework for describing fiscal institutions indicates how our fiscal process invites rent-seeking because it allows beneficiaries of programs to avoid payment for those programs. We conclude by examining how various changes in the fiscal process may influence our public choices