Aircraft Conceptual Structural Design Using the AMMIT Structural Analysis Tool

Aircraft conceptual structural design is the process of developing and refining an idea for an aircraft into a feasible structural design. The process typically involves multiple evaluations of a single configuration and can require designers to examine thousands of concepts. Standard approaches to conducting structural analyses in this phase are either based on the use of historical or empirical data or often require significant expertise in structural analysis to perform these rapid assessments. The AMMIT structural analysis tool includes structural line models and handbook methods wrapped in a simple to use interface that can enable rapid, physics-based structural designs without requiring extensive structural expertise. The objectives of the present paper are to introduce AMMIT, describe the methods used in AMMIT, and present the results of the validation effort. Validation of the AMMIT methodology was performed on nine aircraft to determine the accuracy of the methods, highlight features of AMMIT, and guide future development of the methodology. Results of the validation effort indicated that AMMIT provides a prediction of primary structural weight for each aircraft with an acceptable level of error during the preliminary design phase with a minimal expenditure of computational resources

Critical issues in library management : organizing for leadership and decision-making

Papers from the thirty-fifth Allerton Institute. [October 24-26, 1993]Includes bibliographical references

Introduction to Occasional Paper no. 198/199

published or submitted for publicatio

Myths and Realities of American Political Geography

The division of America into red states and blue states misleadingly suggests that states are split into two camps, but along most dimensions, like political orientation, states are on a continuum. By historical standards, the number of swing states is not particularly low, and America's cultural divisions are not increasing. But despite the flaws of the red state/blue state framework, it does contain two profound truths. First, the heterogeneity of beliefs and attitudes across the United States is enormous and has always been so. Second, political divisions are becoming increasingly religious and cultural. The rise of religious politics is not without precedent, but rather returns us to the pre-New Deal norm. Religious political divisions are so common because religious groups provide politicians the opportunity to send targeted messages that excite their base.

The Causes and Consequences of Land Use Regulation: Evidence from Greater Boston

Over the past 30 years, eastern Massachusetts has seen a remarkable combination of rising home prices and declining supply of new homes. The reductions in new supply don't appear to reflect a real lack of land, but instead reflect a response to man-made restrictions on development. In this paper, we examine the land-use regulations in greater Boston. There has been a large increase in the number of new regulations, which differ widely over space. Few variables, other than historical density and abundant recreational water, reliably predict these regulations. High lot sizes and other regulations are associated with less construction. The regulations boost prices by decreasing density, but density levels seem far too low to maximize total land value.

Myths and Realities of American Political Geography

The division of America into red states and blue states misleadingly suggests that states are split into two camps, but along most dimensions, like political orientation, states are on a continuum. By historical standards, the number of swing states is not particularly low, and America's cultural divisions are not increasing. But despite the flaws of the red state/blue state framework, it does contain two profound truths. First, the heterogeneity of beliefs and attitudes across the United States is enormous and has always been so. Second, political divisions are becoming increasingly religious and cultural. The rise of religious politics is not without precedent, but rather returns us to the pre-New Deal norm. Religious political divisions are so common because religious groups provide politicians the opportunity to send targeted messages that excite their base.