A STUDY IN THE INFORMATION CONTENT, CONSISTENCY, AND EXPRESSIVE POWER OF FUNCTION STRUCTURES IN MECHANICAL DESIGN

In engineering design research, function structures are used to represent the intended functionality of technical artifacts. Function structures are graph-based representations where the nodes are functions, or actions, and the edges are flows, or objects of those actions. For the consistent description of artifact functionality, multiple controlled vocabularies have been developed in previous research. The Functional Basis is one such vocabulary that provides for a set of verbs and a set of nouns, organized in the three-level hierarchy. This vocabulary is extensively studied in design research. Two major application of this vocabulary are the Design Repository, which is a web-base archive of design information of consumer electro-mechanical products obtained through reverse engineering, and the functional decomposition grammar rules that synthesizes sub-functions or elementary actions of a product from the overall function or goal of the product. However, despite the Functional Basis\u27 popularity, the usefulness of its hierarchical structure has not been specifically tested. Additionally, although this vocabulary provides the verbs and nouns, no explicit guideline for using those terms in function structures has been proposed. Consequently, multiple representational inconsistencies can be found in the function structures within the Design Repository. The two research goals in this thesis are: (1) to investigate if the hierarchy in the Functional Basis is useful for constructing function structures and (2) to explore means to increase the consistency and expressive power of the Functional Basis vocabulary. To address the first goal, an information metric for function structures and function vocabularies is developed based on the principles of Information Theory. This metric is applied to three function structures from the Design Repository to demonstrate that the secondary level of the Functional Basis is the most informative of the three. This finding is validated by an external empirical study, which shows that the secondary level is used most frequently in the Design Repository, finally indicating that the hierarchy is not useful for constructing function structures. To address the second research goal, a new representation of functions, including rules the topological connections in a function structure, is presented. It is demonstrated through experiments that the new representation is more expressive than the text-based descriptions of functions used in the Functional Basis, as it formally describes which flows can be connected to which functions. It is also shown that the new representation reduces the uncertainty involved in the individual function structures

A FORMAL REPRESENTATION OF MECHANICAL FUNCTIONS TO SUPPORT PHYSICS-BASED COMPUTATIONAL REASONING IN EARLY MECHANICAL DESIGN

The lack of computational support to the conceptual phase of mechanical engineering design is well recognized. Function-based modeling and thinking is widely recommended in design texts as useful means for describing design concepts and using them in tasks such as solution search, problem decomposition, and design archival. Graph-based function structure models that describe a product as a network of transformative actions of material, energy, and information, are discussed as a potential tool for this purpose, but in the current state of the art, function structures are not formalized as a computational representation. Consequently, no computer tool exists with which a designer can construct grammatically controlled function structure models, explore design ideas by model editing, and perform automated reasoning on the model against the laws of nature to draw analytical inferences on the design. This research presents, verifies, and validates a formal representation of mechanical functions that supports consistent computer-aided modeling of early design and reasoning on those models based on two universal principles of physics: (1) conservation and (2) irreversibility. The representation is complete in three layers. The first layer--the Conservation Layer--is defined with nine entities, five relations, five attributes, and 33 grammar rules that together formalize the construction of function structure graphs and support conservation-based qualitative validation of design concepts. The second layer--the Irreversibility Layer--includes three additional attributes that support both conservation-based and irreversibility-based reasoning at qualitative and quantitative levels. The third layer--the Semantic Layer--is an extension of the previous two, where a vocabulary of nine verbs that describe mechanical devices and physical principles as functions is proposed. This layer supports feature-based modeling and semantic reasoning of function structures. The internal consistency of the representation is verified by logical examination and ontological consistency checking using Protégé-OWL. The coverage of the verbs is examined by constructing descriptive function structure models of a variety of existing physical principles and devices. The research is validated by incorporating the representation in a software tool using an object-oriented language and graphic user-interface, and by using the tool to construct models and demonstrate conservation-based and irreversibility-based reasoning

Post-Cold War Economic Espionage in the United States

Literature abounds on post-Cold War economic espionage. But none has dealt with the American policy position in a thorough manner. This present inquiry utilizes two survey reports and complimentary literature to address the following questions: (1) Is there a real threat to the United States from economic espionage? (2) If there is, what are the major sources of threat? and (3) What are and ought to be the U.S. government response? Results indicate that the threat from economic espionage is real and increasng. In global information economy critical technology is essential for power. Since the United States leads in innovations, its economic adversaries are engaging their national spy services to purloin U.S. technology. But America has taken serious cognizance of this threat and may have also commenced countereconomic espionage. These findings imply that for any country to defeat the United States economically and militariality, it has either to be first in innovations or gain access to America\u27s innovation foundation through economic espionage

Thoughts on Benchmarking of Function Modeling: Why and How

This special issue provides a justification and a proposed research direction for establishing a common benchmarking scheme for function representations that are developed and deployed throughout academia and practice with the ultimate goal of providing industry with practically usable function modelling tools and concepts