9,289 research outputs found

    A Theory of Cheap Control in Embodied Systems

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    We present a framework for designing cheap control architectures for embodied agents. Our derivation is guided by the classical problem of universal approximation, whereby we explore the possibility of exploiting the agent's embodiment for a new and more efficient universal approximation of behaviors generated by sensorimotor control. This embodied universal approximation is compared with the classical non-embodied universal approximation. To exemplify our approach, we present a detailed quantitative case study for policy models defined in terms of conditional restricted Boltzmann machines. In contrast to non-embodied universal approximation, which requires an exponential number of parameters, in the embodied setting we are able to generate all possible behaviors with a drastically smaller model, thus obtaining cheap universal approximation. We test and corroborate the theory experimentally with a six-legged walking machine. The experiments show that the sufficient controller complexity predicted by our theory is tight, which means that the theory has direct practical implications. Keywords: cheap design, embodiment, sensorimotor loop, universal approximation, conditional restricted Boltzmann machineComment: 27 pages, 10 figure

    TECHNICAL CHANGE IN AGRICULTURE

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    Research and Development/Tech Change/Emerging Technologies,

    cost estimation method for gas turbine in conceptual design phase

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    Abstract Introduction of new gas turbine machines on market is a complex project that requires optimization of different performance parameters such as power, efficiency, maintenance plan, product cost and life. The ability to control cost and impact on performances and life strongly decreases from conceptual to detailed design phase. Actually, 80 % of product's cost and performances are committed based on decisions made in conceptual design. This Paper describes a systematic procedure to estimate the cost of multiple design alternatives during conceptual design phase, comparing different cross sections for gas turbine solutions. Examples of parametric costing tool for part family will be described, to show the approach that allows to estimate costs in conceptual design phase, when detailed design has not been developed and lack of information is a daily topic. The idea is to be able to read design information of each part from an enhanced cross section and enter parametric costing tool to have a preliminary cost estimation in conceptual phase. Doing that for each part or module present, it will be possible to estimate total cost of the product. The scope is to create an internal database where the whole know-how and best practices are stored. This database can be examined in early program stages, to reduce time to market and avoid pursuing solutions that would not be viable or convenient, in a sort of digital twin approach. Another positive aspect pursued and presented, is the positive impact on engineering productivity, that directly reflects on program development cost

    Model and Simulation of Heavy Load Carrier Mechanism

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    Heavy load carrier is a mechanism use to ease the lifting of heavy load by reducing the force need and increase the capacity of the load.The design of the heavy load carrier is to improve the working condition mostly for the labor and personal use. Thus, the heavy load carrier can be used to move the load in short distance without using any vehicle such as lorry or forklift which can reduce the cost of transportation. The heavy load carrier must be applicable in multi terrain which mean can be use on level ground or stair-like terrain. Moreover, the ability of the heavy load carrier which can be used in multi terrain is due to its capability to lift the load in multi method base on applicable terrain. The multi method of lifting the load such as trolley, backpack, wheel bag luggage and other manual lifting had being combined together in this mechanism. The heavy load carrier shape and degree of freedom can be change easily base on the method of lifting. The heavy load carrier installed by tire and handle with steady and sturdy frame. While the heavy load carrier used in level ground the shape of wheel bag luggage can be used, for small quantity of load the heavy load can be push with two tires and string to support the load. While for huge quantity of load the shape of heavy load change to trolley. The handle used to push the heavy load before will be use as the frame to support the load with the help of string.Then the trolley can be pull by the beam as a handle. Furthermore, in stair-like terrain, the heavy load can be change into the back-pack shape which the handle for the bag luggage shape will be use as a support to carry the load from the ground

    NASA patent abstracts bibliography: A continuing bibliography. Section 1: Abstracts (supplement 38)

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    Abstracts are provided for 132 patents and patent applications entered into the NASA scientific and technical information system during the period July 1990 through December 1990. Each entry consists of a citation, an abstract, and in most cases, a key illustration selected from the patent or patent application

    Eco-Evaluation in Conceptual Design Phase – A Case Study

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    The use of qualitative eco-evaluation methods for product concept eco-evaluation is explored in a case study where mechanical engineers performed an eco-evaluation of product concepts in a two-stage evaluation process. In the first stage of the case study, the evaluators were asked to evaluate the environmental friendliness of the product concepts and to rank the concepts accordingly. The obtained rankings were based upon subjective preferences of the evaluators and their subjective interpretation of the eco-value of the considered concepts. In the second stage of the case study, the evaluators eco-evaluated the same concepts, but this time they used ecodesign guidelines as eco-criteria. The evaluators have obtained different rankings of the concepts, so the results of the two sets of rankings are compared. Findings are analysed in the context of confounding variables of the case study design

    A Multi-objective Design Approach to Include Material, Manufacturing and Assembly Costs in the Early Design Phase

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    AbstractConceptual design is a crucial activity in the product development process. The design freedom must consider a trade-off analysis among several aspects such as assembly, manufacturing, and costs. The goal of this approach is to define a multi-objective design approach for the determination of feasible design options. The approach is grounded on the concept of functional basis for the analysis of product modules and the theory of Multi Criteria Decision Making (MCDM) approach for the assessment of the best design option. A complex product (tool-holder carousel of a machine tool) is used as a case study to validate the approach

    Bayesian Network Approach to Assessing System Reliability for Improving System Design and Optimizing System Maintenance

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    abstract: A quantitative analysis of a system that has a complex reliability structure always involves considerable challenges. This dissertation mainly addresses uncertainty in- herent in complicated reliability structures that may cause unexpected and undesired results. The reliability structure uncertainty cannot be handled by the traditional relia- bility analysis tools such as Fault Tree and Reliability Block Diagram due to their deterministic Boolean logic. Therefore, I employ Bayesian network that provides a flexible modeling method for building a multivariate distribution. By representing a system reliability structure as a joint distribution, the uncertainty and correlations existing between system’s elements can effectively be modeled in a probabilistic man- ner. This dissertation focuses on analyzing system reliability for the entire system life cycle, particularly, production stage and early design stages. In production stage, the research investigates a system that is continuously mon- itored by on-board sensors. With modeling the complex reliability structure by Bayesian network integrated with various stochastic processes, I propose several methodologies that evaluate system reliability on real-time basis and optimize main- tenance schedules. In early design stages, the research aims to predict system reliability based on the current system design and to improve the design if necessary. The three main challenges in this research are: 1) the lack of field failure data, 2) the complex reliability structure and 3) how to effectively improve the design. To tackle the difficulties, I present several modeling approaches using Bayesian inference and nonparametric Bayesian network where the system is explicitly analyzed through the sensitivity analysis. In addition, this modeling approach is enhanced by incorporating a temporal dimension. However, the nonparametric Bayesian network approach generally accompanies with high computational efforts, especially, when a complex and large system is modeled. To alleviate this computational burden, I also suggest to building a surrogate model with quantile regression. In summary, this dissertation studies and explores the use of Bayesian network in analyzing complex systems. All proposed methodologies are demonstrated by case studies.Dissertation/ThesisDoctoral Dissertation Industrial Engineering 201

    A systematic approach for integrated product, materials, and design-process design

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    Designers are challenged to manage customer, technology, and socio-economic uncertainty causing dynamic, unquenchable demands on limited resources. In this context, increased concept flexibility, referring to a designer s ability to generate concepts, is crucial. Concept flexibility can be significantly increased through the integrated design of product and material concepts. Hence, the challenge is to leverage knowledge of material structure-property relations that significantly affect system concepts for function-based, systematic design of product and materials concepts in an integrated fashion. However, having selected an integrated product and material system concept, managing complexity in embodiment design-processes is important. Facing a complex network of decisions and evolving analysis models a designer needs the flexibility to systematically generate and evaluate embodiment design-process alternatives. In order to address these challenges and respond to the primary research question of how to increase a designer s concept and design-process flexibility to enhance product creation in the conceptual and early embodiment design phases, the primary hypothesis in this dissertation is embodied as a systematic approach for integrated product, materials and design-process design. The systematic approach consists of two components i) a function-based, systematic approach to the integrated design of product and material concepts from a systems perspective, and ii) a systematic strategy to design-process generation and selection based on a decision-centric perspective and a value-of-information-based Process Performance Indicator. The systematic approach is validated using the validation-square approach that consists of theoretical and empirical validation. Empirical validation of the framework is carried out using various examples including: i) design of a reactive material containment system, and ii) design of an optoelectronic communication system.Ph.D.Committee Chair: Allen, Janet K.; Committee Member: Aidun, Cyrus K.; Committee Member: Klein, Benjamin; Committee Member: McDowell, David L.; Committee Member: Mistree, Farrokh; Committee Member: Yoder, Douglas P
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