815 research outputs found
“Do-Not-Call-List” Testimony: Before the Senate Committee on Commerce, Science, and Transportation
Mr. Chairman, members of the Committee, thank you for the opportunity to be here with you today. My name is Jim Guest, and I am President of Consumers Union, the independent, non- profit publisher of Consumer Reports magazine and ConsumerReports.org, with over ve million subscribers
Making a Difference: Measuring the Effectiveness of Mississippi Teacher Corps Teachers as Compared to Non-Mississippi Teacher Corps Teachers
The Mississippi Teacher Corps (MTC) was founded in 1989. Over the past 23 years more than 500 MTC participants have taught in critical-needs schools in Mississippi. The purpose of this study was to examine the effectiveness of Mississippi Teacher Corps teachers as compared to non-Mississippi Teacher Corps teachers. The method of research was a quantitative analysis of standardized test scores from the Rural County School District for school year 2009–2010. The analysis shothat there is no significant difference in mean test scores of students who are taught by MTC teachers as compared to non-MTC teachers but that, in both the fall and spring, student test scores are significantly higher in MTC classrooms
Modeling Social Influence via Combined Centralized and Distributed Planning Control
Real world events are driven by a mixture of both centralized and distributed control of individual agents based on their situational context and internal make up. For example, some people have partial allegiances to multiple, contradictory authorities, as well as to their own goals and principles. This can create a cognitive dissonance that can be exploited by an appropriately directed psychological influence operation (PSYOP). An Autonomous Dynamic Planning and Execution (ADP&E) approach is proposed for modeling both the unperturbed context as well as its reaction to various PSYOP interventions. As an illustrative example, the unrest surrounding the Iranian elections in the summer of 2009 is described in terms applicable to an ADP&E modeling approach. Aspects of the ADP&E modeling process are discussed to illustrate its application and advantages for this example
Optimal Design of Trusses With Geometric Imperfections: Accounting for Global Instability
A topology optimization method is proposed for the design of trusses with random geometric imperfections due to fabrication errors. This method is a generalization of a previously developed perturbation approach to topology optimization under geometric uncertainties. The main novelty in the present paper is that the objective function includes the nonlinear effects of potential buckling due to misaligned structural members. Solutions are therefore dependent on the magnitude of applied loads and the direction of resulting internal member forces (whether they are compression or tension). Direct differentiation is used in the sensitivity analysis, and analytical expressions for the associated derivatives are derived in a form that is computationally efficient. A series of examples illustrate how the effects of geometric imperfections and buckling may have substantial influence on truss design. Monte Carlo simulation together with second-order elastic analysis is used to verify that solutions offer improved performance in the presence of geometric uncertainties
Optimal Design of Trusses With Geometric Imperfections
The present paper focuses on optimization of trusses that have randomness in geometry that may arise from fabrication errors. The analysis herein is a generalization of a perturbation approach to topology optimization under geometric uncertainties. The main novelty in the present paper is in the consideration of potential buckling due to misaligned structural members. The paper begins with a brief review of the aforementioned perturbation approach, then proceeds with the analysis of the nonlinear effects of geometric imperfection. The paper concludes with some numerical examples
Completing the life cycle of a broadcast spawning coral in a closed mesocosm
Studies of broadcast spawning in corals are fundamental to our understanding of early life history
characteristics, reproductive biology, restoration etc. Spawning of corals for research is routinely
conducted, but this is mostly restricted to sites adjacent to reefs and from broodstock collected
from the wild just prior to gamete release. Only recently has it been possible to induce predictable
broadcast spawning in an ex situ environment, and nobody has successfully closed the life cycle
(i.e., production of an F2 generation) of these corals. Here, for the first time, we closed the life cycle
of the broadcast spawning coral Acropora millepora in a fully closed ex situ mesocosm. This
breakthrough has numerous implications for our understanding of reproductive biology, specifically it offers potential to deepen our understanding of the genetic influence on adaptive traits
such as heat tolerance, growth and disease resistance over multiple generations
Illinois State University Wind Symphony, April 6, 2022
Center for the Performing Arts
April 6, 2022
Wednesday Evening
8:00 p.m
When is a symmetric pin-jointed framework isostatic?
Maxwell's rule from 1864 gives a necessary condition for a framework to be
isostatic in 2D or in 3D. Given a framework with point group symmetry, group
representation theory is exploited to provide further necessary conditions.
This paper shows how, for an isostatic framework, these conditions imply very
simply stated restrictions on the numbers of those structural components that
are unshifted by the symmetry operations of the framework. In particular, it
turns out that an isostatic framework in 2D can belong to one of only six point
groups. Some conjectures and initial results are presented that would give
sufficient conditions (in both 2D and 3D) for a framework that is realized
generically for a given symmetry group to be an isostatic framework.Comment: 24 pages, 10 figures; added references, minor changes, revised last
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