Volume 10 Issue 2 September 2011

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https://doi.org/10.33697/ajur.2011.011

Editorial: A Lack of Sustained Focus on STEM Education in the US

https://doi.org/10.33697/ajur.2011.012

Author(s):

C. C. Chancey

Affiliation:

University of Northern Iowa, Cedar Falls, Iowa 50614-0150 USA


Algorithms for Collective Construction of 2D Block Structures with Holes

https://doi.org/10.33697/ajur.2011.013

Author(s):

Zachary Fitzsimmons and Robin Flatland

Affiliation:

Department of Computer Science, Siena College, Loudonville, New York 12211 USA

ABSTRACT:

In this paper we present algorithms for collective construction systems in which a large number of autonomous mobile robots transport modular building elements to construct a desired structure. We focus on building block structures subject to some physical constraints that restrict the order in which the blocks may be attached to the structure. Specifically, we determine a partial ordering on the blocks such that if they are attached in accordance with this ordering, then (i) the structure is a single, connected piece at all intermediate stages of construction, and (ii) no block is attached between two other previously attached blocks, since such a space is too narrow for a robot to maneuver a block into it. Previous work has consider this problem for building 2D structures without holes. Here we consider 2D structures with holes. We model the problem as a graph orientation problem and describe an O(n2) algorithm for solving it. We also describe how this partial ordering may be used in a distributed fashion by the robots to coordinate their actions during the building process.


A deterministic model for (n = 2) competitive products in a market system

https://doi.org/10.33697/ajur.2011.014

Author(s):

M. C. Kekana and O. D. Makinde

Affiliation:

Tshwane University of Technology, Private Bag X680, Pretoria 0001, Staatsartillerie Road, Pretoria West, Republic of South Africa

ABSTRACT:

We proposed a new deterministic model for the dynamics of two competitive products in a given market system. The model was analyzed qualitatively to determine the stability of its equilibrium under the influence of factors such as advertisement, personal interaction, immigration and emigration. Numerical verification of the analytical results is performed and presented graphically.


Using Web 2.0 Data to Estimate Alcohol-Related Travel

https://doi.org/10.33697/ajur.2011.015

Author(s):

William Conroy and Duncan Smith

Affiliation:

Department of Geography, University of Washington, Box 353550, Smith Hall 408, Seattle, Washington 98195 USA

ABSTRACT:

Using ArcGIS, the locations of pubs, clubs, and bars were geocoded onto the street network of Seattle. Upon calculating the density of these drinking establishments throughout the city, the six densest areas, representing nightlife districts, were converted to polygons. Using publicly available check-in data from Gowalla, user check in data within these six polygons was obtained. After cross referencing the Gowalla users’ legal names with the Washington State Voter Registration Database, straight line distances between their legal addresses and bars patronized were calculated. As a result, distance traveled profiles were calculated for each nightlife district.