The absence of efficient dual pairs of spanning trees in planar graphs

A spanning tree T in a finite planar connected graph G determines a dual spanning tree T* in the dual graph G such that T and T* do not intersect. We show that it is not always possible to find T in G, such that the diameters of T and T* are both within a uniform multiplicative constant (independent of G) of the diameters of their ambient graphs.Comment: 7 pages, 3 figure

Suspension Design, Modeling, and Testing of a Thermo-Acoustic-Driven Linear Alternator

The Score-Stove™ generates electricity from a wood-burning cooking stove using a thermo-acoustic engine (TAE) that converts heat to sound through a linear alternator (LA). This paper introduces a prototype hemitoroidal suspension that was refined into a segmented trapezoidal shape that gave a higher cyclic life for the LA and includes a critical evaluation that compares a theoretical analysis with experimental results. The results show an improvement from the 40% efficiency of a standard loudspeaker used in reverse as an LA to 70–80% efficiency with the new suspension and a double Halbach array magnetic topology

Spectral irradiance of total and spectral energy standards

Spectral irradiance measurements of tungsten and carbon filament lamps for energy standards and accuracy limits used in space simulator

Analysing the behaviour of robot teams through relational sequential pattern mining

This report outlines the use of a relational representation in a Multi-Agent domain to model the behaviour of the whole system. A desired property in this systems is the ability of the team members to work together to achieve a common goal in a cooperative manner. The aim is to define a systematic method to verify the effective collaboration among the members of a team and comparing the different multi-agent behaviours. Using external observations of a Multi-Agent System to analyse, model, recognize agent behaviour could be very useful to direct team actions. In particular, this report focuses on the challenge of autonomous unsupervised sequential learning of the team's behaviour from observations. Our approach allows to learn a symbolic sequence (a relational representation) to translate raw multi-agent, multi-variate observations of a dynamic, complex environment, into a set of sequential behaviours that are characteristic of the team in question, represented by a set of sequences expressed in first-order logic atoms. We propose to use a relational learning algorithm to mine meaningful frequent patterns among the relational sequences to characterise team behaviours. We compared the performance of two teams in the RoboCup four-legged league environment, that have a very different approach to the game. One uses a Case Based Reasoning approach, the other uses a pure reactive behaviour.Comment: 25 page

Sensitivity of mixing layers to three-dimensional forcing

It is well known that turbulent mixing layers are dominated by large scale, fairly coherent structures, and that these structures are related to the stability characteristics of the flow. These facts have led researchers to attempt controlling such flows by selectively forcing certain unstable modes, which can in addition have the effect of suppressing other modes. Much of the work on controlling the mixing layer has relied on forcing 2-D instabilities. The results of forcing 3-D instabilities are addressed. The objectives of the work are twofold: to understand how a mixing layer responds to 3-D perturbations, and to test the validity of an amplitude expansion in predicting the mixing layer development. The amplitude expansion could be very useful in understanding and predicting the 3-D response of the flow to a variety of initial conditions

South Dakota\u27s Hutterite Colonies: 1874-1969

This publication is divided into three major parts. The first part attempts to answer such questions as Who are the Hutterites? What do they believe? and Where are they in South Dakota? The second part reports on the 1968 census of these communal farms and summarizes the sect\u27s enterprises and changes in farm operations. The third part presents a pictorial account of Poinsett Colony, one of the newest Hutterite colonies in South Dakota

CHROMOSOME NUMBERS OF RELEASED CULTIVARS OF SWITCHGRASS, INDIANGRASS, BIG BLUESTEM, AND SAND BLUESTEM

Chromosome numbers of cultivars of switchgrass (Panicum virgatum L.), indiangrass (Sorghastrum nutans L.) and the tall bluestem complex of big bluestem (Andropogon gerardi Vitman.) and sand bluestem (Andropogon hallii Hack.) were determined. Ploidy levels of these cultivars have not been reported previously even though these grasses have been reported to have two or more ploidy levels. Switchgrass cultivars \u27Pathfinder\u27, \u27Blackwell\u27, and \u27Nebraska 28\u27 were hexaploids (2n = 54), while \u27Summer\u27 and \u27Kanlow\u27 were tetraploids (2n = 36). Indiangrass cultivars \u27Nebraska 54\u27, \u27Oto\u27, \u27Osage\u27, and \u27Holt\u27 were all tetraploids (2n = 40). Big bluestem cultivars \u27Pawnee\u27 and \u27Kaw\u27 and the sand bluestem cultivar \u27Goldstrike\u27 were hexaploids (2n = 60). Meiosis was normal with bivalent pairing for most plants examined from all three grasses

South Dakota Population and Net Migration: 1960-1970

This publication is a contribution of the South Dakota Agricultural Experiment Station to the North Central Region Cooperative Research Project NC-97, The Relation of Population to Social Changes in the North Central Region. The South Dakota Project is conducted in the Department of Rural Sociology, Project 543

The Hutterites: South Dakota\u27s Communal Farmers

This publication is divided into two major parts: the first part attempts to answer such questions as who are the Hutterites, what they believe, and where they are located in South Dakota. The second part reports on the 1964 census of these communal farms and summarized the sect’s agricultural enterprises and changes in farm operations