A Smart Contract Oracle for Approximating Real-World, Real Number Values

A key challenge of smart contract systems is the fact that many useful contracts require access to information that does not natively live on the blockchain. While miners can verify the value of a hash or the validity of a digital signature, they cannot determine who won an election, whether there is a flood in Paris, or even what is the price of ether in US dollars, even though this information might be necessary to execute prediction market, insurance, or financial contracts respectively. A number of promising projects and research developments have provided a better understanding of how one might construct a decentralized, binary oracle - namely an oracle that can respond by one of two possibilities, typically "yes" or "no", even while not requiring the interaction of a trusted third party. In this work, we extend these ideas to construct a general-purpose, decentralized oracle that can estimate the value of a real-world quantity that is in a dense totally ordered set, such as R. In particular, this proposal can be used to estimate real number valued quantities, such as required for a price oracle. We will establish a number of desirable properties about this proposal. Particularly, we will see that the precision of the output is tunable to users\u27 needs

Remixing the music curriculum : the new technology, creativity and perceptions of musicality in music education

Abstract\ud This thesis interrogates the new music technology and its relationship to\ud creativity, musicality and learning in the Key Stage 31 curriculum. In doing so it\ud considers the effectiveness of the technology, what value pupils and teachers\ud might place on technologically mediated musical interactions and how this\ud relates to the principles enshrined in the National Curriculum. The research also\ud explores the views of teachers in relation to the nature of creativity and learning\ud in the music curriculum and their role in promoting it. The research was carried\ud out across five sites: a PGCE music course, a year 7, year 8, and year 9 Key Stage\ud 3 music classroom, and a panel of secondary music teachers. It was located in a\ud qualitative paradigm which made use of observational and interview techniques.\ud The research also probed the pupils' creative outcomes through detailed\ud analysis. The findings suggest that the new technology can afford creative\ud musical engagement through the manipulation of ready-made musical materials.\ud It also suggests that pupils engage in a range of musical learning through such\ud interactions and that they value the processes and outcomes. By way of contrast,\ud teachers are still unclear about how to value such musical actions and are in the\ud process of re conceptualising the learning that emerges in technologically\ud mediated settings. Moreover, confusions still exist in relation to creativity and\ud learning in the music classroom. This is compounded by the fact that the pupils'\ud musical actions in relation to the new technology do not meet certain core\ud practices and principles enshrined in the National Curriculum for music. This is\ud problematic for, as the research suggests, such core practices often exclude or\ud distance those pupils who are non-performing musicians. Hence the thesis\ud concludes by positing that music education must consider a broader view of\ud what it is to be musical. In doing so it needs to remix the music curriculum to\ud take account of a range of musical actions. This remix should accommodate the\ud new technology, reconfigure musical creativity and learning in the light of the\ud technology and find new ways to value pupils' actions. In such settings the role of\ud the teacher in shaping and supporting the pupils' musical actions will be an\ud important consideration

Tricresyl Phosphate Neurotoxicity Potential

Mr. Sherk discusses the potential effects of ongoing human exposure to ordinary doses of neurotoxicants

The use of plant functional types as a method of determining plant biodiversity and keystoneness in a northern New Zealand isocline : a thesis presented in partial fulfilment of the requirements for the degree of Master of Applied Science in Plant Science at Massey University, New Zealand

New Zealand vegetation, like the rest of the world, is undergoing increased perturbations due to global climate change. Whether anthropocentric in origin or part of a natural climatic cycle, increased CO₂, increased temperature plus changing regimes of precipitation have been recorded. Environmental change, especially at local levels, does affect community structure. New Zealand's ancient endemic trees and shrubs face the greatest threat of extinction, mainly due to habitat destruction by man for development and by introduced pests. The consequence could be that these trees and shrubs would not be able to migrate naturally in the time frame that climatic change will allow. The use of Plant Functional Types in climate change research is extensive and these groupings are being used more frequently in the study of diversity response to environmental change. The objectives of the Maunganui Bluff study were to develop a methodology to construct PFTs and to utilise these functional groupings in an analysis of the isocline. These analyses were; a diversity study based on richness and abundance, a site ordination and a group analysis. A total of forty-eight PFTs were constructed, then reduced to seventeen. The final seventeen functional groups were used in the following analyses. 1. A diversity analysis. While not appearing useful in comparing species evenness to PFT evenness over the isocline, the analysis did confirm that at that point in space and time when sampling was undertaken, PFTs did conform to the assembly rule for groups. This rule states that there should be equal representation of functional groups at each site from the total available pool 2. Ordination. The second analysis was to determine the effect of the local environment on the spatial position of the PFTs on the isocline. Detrended Correlation Analysis (DCA), an ordination technique, was used to map the groups and the sites against environmental gradients. The results signified that a small number of groups were strongly influenced by potassium (K) but the majority of groups occupied specific sites, on an altitude – phosphorus and nitrogen gradient, due to competition for resources. This summation is supported by altitude being linked to precipitation and leaching, since most of the other environmental data, measured and analysed, were correlated to altitude. 3. Group analysis using Indicator Species Analysis in the computer programme PCORD. The statistical analysis highlighted three PFTs with high keystone rankings p*>.800), one of which was missed by a subjective analysis of the site map of PFTs distribution. When these three groups were deconstructed back to species, the membership of each group was only one species. Of these three species, only Haloragis erecta appeared to be out of place within the gradient. Four hundred metres in altitude is well beyond the plants recognised limit of approximately 120 metres. Since sea level to one hundred and fifty metres is the shrubland zone and site K is also, by species sampled, designated a shrubland, there is evidence that some environmental factor may be associated with these sites. Obviously, this cannot be tested, as there were no Haloragis erecta in the sampled sites from sea level to one hundred and fifty metres. The analysis suffered from a lack of replication for the site under study, as well as comparative sites, to determine the validity of the methodologies. The results while encouraging only reflect a point in both space and time. The work would have needed a much larger range of environmental data, over a longer time frame to ensure that the results were not chance, and would be sustained under more detailed statistical rigor. Many of the premises that the work was based on are subjective. However, despite the lack of statistical rigor, the study confirms the work being carried out using PFTs in other countries. New Zealand's endemic plants do have assembly rules and PFTs constructed with New Zealand natives are valid assemblages that can be used in statistical analysis, and may well turn out to be important in monitoring environmental change

The first American historian--William Bradford

Thesis (M.A.)--Boston Universit

Transit Thermal Control Design for Galileo Entry Probe for Planet Jupiter

A totally passive design was completed for the thermal control of the Galileo entry probe during its transit to the planet Jupiter. The design utilizes radio isotope heater units, multilayer insulation blankets and a thermal radiator in conjunction with a design conductance support structure to achieve both the required storage and critical initial planet atmosphere entry temperatures. The probe transit thermal design was completed and verified based on thermal vacuum testing of a prototype probe thermal test model

A study of the performance of the 1951 and 1952 graduates of the Boston University Graduate Workshop in Elementary Education.

Thesis (Ed.M.)--Boston Universit

Far-Field Compression for Fast Kernel Summation Methods in High Dimensions

We consider fast kernel summations in high dimensions: given a large set of points in $d$ dimensions (with $d \gg 3$) and a pair-potential function (the {\em kernel} function), we compute a weighted sum of all pairwise kernel interactions for each point in the set. Direct summation is equivalent to a (dense) matrix-vector multiplication and scales quadratically with the number of points. Fast kernel summation algorithms reduce this cost to log-linear or linear complexity. Treecodes and Fast Multipole Methods (FMMs) deliver tremendous speedups by constructing approximate representations of interactions of points that are far from each other. In algebraic terms, these representations correspond to low-rank approximations of blocks of the overall interaction matrix. Existing approaches require an excessive number of kernel evaluations with increasing $d$ and number of points in the dataset. To address this issue, we use a randomized algebraic approach in which we first sample the rows of a block and then construct its approximate, low-rank interpolative decomposition. We examine the feasibility of this approach theoretically and experimentally. We provide a new theoretical result showing a tighter bound on the reconstruction error from uniformly sampling rows than the existing state-of-the-art. We demonstrate that our sampling approach is competitive with existing (but prohibitively expensive) methods from the literature. We also construct kernel matrices for the Laplacian, Gaussian, and polynomial kernels -- all commonly used in physics and data analysis. We explore the numerical properties of blocks of these matrices, and show that they are amenable to our approach. Depending on the data set, our randomized algorithm can successfully compute low rank approximations in high dimensions. We report results for data sets with ambient dimensions from four to 1,000.Comment: 43 pages, 21 figure