Alice M. Agogino

Engineering design thinking, teaching, and learning

This paper is based on the premises that the purpose of engineering education is to graduate engineers who can design, and that design thinking is complex. The paper begins by briefly reviewing the history and role of design in the engineering curriculum. Several dimensions of design thinking are then detailed, explaining why design is hard to learn and harder still to teach, and outlining the research available on how well design thinking skills are learned. The currently most-favored pedagogical model for teaching design, project-based learning (PBL), is explored next, along with available assessment data on its success. Two contexts for PBL are emphasized: first-year cornerstone courses and globally dispersed PBL courses. Finally, the paper lists some of the open research questions that must be answered to identify the best pedagogical practices of improving design learning, after which it closes by making recommendations for research aimed at enhancing design learning.

A resonant accelerometer with two-stage microleverage mechanisms fabricated by SOI-MEMS technology

We present the design, fabrication, and testing of a push-pull differential resonant accelerometer with double-ended-tuning-fork (DETF) as the inertial force sensor. The accelerometer is fabricated with the silicon-on-insulator microelectromechanical systems (MEMS) technology that bridges surface micromachining and bulk micromachining by integrating the 50-/spl mu/m-thick high-aspect ratio MEMS structure with the standard circuit foundry process. Two DETF resonators serve as the force sensor measuring the acceleration through a frequency shift caused by the inertial force acting as axial loading. Two-stage microleverage mechanisms with an amplification factor of 80 are designed for force amplification to increase the overall sensitivity to 160 Hz/g, which is confirmed by the experimental value of 158 Hz/g. Trans-resistance amplifiers are designed and integrated on the same chip for output signal amplification and processing. The 50-/spl mu/m thickness of the high-aspect ratio MEMS structure has no effect on the amplification factor of the mechanism but contributes to a greater capacitance force; therefore, the resonator can be actuated by a much lower ac voltage comparing to the 2-/spl mu/m-thick DETF resonators. The testing results agree with the designed sensitivity for static acceleration.

Optimized Design of MEMS by Evolutionary Multi-objective Optimization with Interactive Evolutionary Computation

We combine interactive evolutionary computation (IEC) with existing evolutionary synthesis software for the design of micromachined resonators and evaluate its effectiveness using human evaluation of the final designs and a test for statistical significance of the improvements. The addition of IEC produces superior designs with fewer potential design or manufacturing problems than those produced through the evolutionary synthesis software alone as it takes advantage of the human ability to perceive design flaws that cannot currently be simulated. A user study has been performed to compare the effectiveness of the IEC enhanced software with the non-interactive software. The results show that the IEC-enhanced synthesis software creates a statistically significant greater number of designs rated best by users.

Text Analysis for Constructing Design Representations

An emerging model in concurrent product design and manufacturing is the federation of workgroups across traditional functional “silos.” Along with the benefits of this concurrency comes the complexity of sharing and accessing design information. The primary challenge in sharing design information across functional workgroups lies in reducing the complex expressions of associations between design elements. Collaborative design systems have addressed this problem from the perspective of formalizing a shared ontology or product model. We share the perspective that the design model and ontology are an expression of the “meaning” of the design and provide a means by which information sharing in design may be achieved. However, in many design cases, formalizing an ontology before the design begins, establishing the knowledge sharing agreements or mapping out the design hierarchy is potentially more expensive than the design itself. This paper introduces a technique for inducing a representation of the design based upon the syntactic patterns contained in the corpus of design documents. The association between the design and the representation for the design is captured by basing the representation on terminological patterns in the design text. In the first stage, we create a “dictionary” of noun-phrases found in the text corpus based upon a measurement of the content carrying power of the phrase. In the second stage, we cluster the words to discover inter-term dependencies and build a Bayesian belief network which describes a conceptual hierarchy specific to the domain of the design. We integrate the design document learning system with an agent-based collaborative design system for fetching design information based on the “smart drawings” paradigm.

Wireless networked lighting systems for optimizing energy savings and user satisfaction

Energy savings and user satisfaction are two major design considerations for modern lighting systems. While some new commercial lighting systems for shared-space office buildings have been able to achieve significant savings via various lighting control strategies, the occupantspsila diverse lighting preferences and visual comfort have been generally overlooked or even compromised. Moreover, retrofitting legacy buildings with modern lighting systems is still economically unattractive due to the high cost of global rewiring. Leveraging the versatility of wireless sensor and actuator network technologies, this paper describes a wireless networked lighting system that fulfills both design criteria for modern lighting systems - energy efficiency and user satisfaction. The intelligent lighting optimization algorithm formulates lighting control as a linear programming problem to minimize energy usage and meet occupantspsila lighting preferences at the same time. The hardware of the lighting system is designed with minimizing retrofitting efforts and costs in mind, and an implementation of the developed system in a multiperson office shows substantial energy savings while meeting userspsila lighting preferences.

Multiple sensor expert system for diagnostic reasoning, monitoring and control of mechanical systems

Abstract This paper describes an expert systems architecture for integrating multiple sensors for diagnostic reasoning, monitoring and supervisory control of mechanical systms in automated manufacturing and process control. The IDES (Influence Diagram based Expert System) performs probabilistic inference and expected value decision making. It integrates dynamic sensor readings, statistical data and subjective expertise in symbolic and numerical data structures and is designed for real time performance. An application using acoustic, current and force sensors on a numerically-controlled milling machine is described. In this example, the fusion of information from multiple sensors achieves effective prediction and control performance with relatively simple signal processing.

Innovative design of mechanical structures from first principles

Design is a complex phenomenon which often requires solutions beyond the routine. Generation of innovative designs in the mechanical/structural domain requires deep level reasoning capabilities to determine how to modify an existing design. This dissertation proposes that computational methodologies can innovate optimally directed designs by reasoning from first principle knowledge. The dissertation introduces a non-routine design methodology called 1

IDES: influence diagram based expert system

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Control of wireless-networked lighting in open-plan offices

PRINCE (FIRST PRINciple Computational Evaluator) based on the assumption that the creation of innovative designs of physical significance requires first principle knowledge to reason about geometric and material properties. The innovative designs discovered by 1

Automated Construction of Sparse Bayesian Networks from Unstructured Probabilistic Models and Domain Information

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