12,173 research outputs found

    An assembly oriented design framework for product structure engineering and assembly sequence planning

    Get PDF
    The paper describes a novel framework for an assembly-oriented design (AOD) approach as a new functional product lifecycle management (PLM) strategy, by considering product design and assembly sequence planning phases concurrently. Integration issues of product life cycle into the product development process have received much attention over the last two decades, especially at the detailed design stage. The main objective of the research is to define assembly sequence into preliminary design stages by introducing and applying assembly process knowledge in order to provide an assembly context knowledge to support life-oriented product development process, particularly for product structuring. The proposed framework highlights a novel algorithm based on a mathematical model integrating boundary conditions related to DFA rules, engineering decisions for assembly sequence and the product structure definition. This framework has been implemented in a new system called PEGASUS considered as an AOD module for a PLM system. A case study of applying the framework to a catalytic-converter and diesel particulate filter sub-system, belonging to an exhaust system from an industrial automotive supplier, is introduced to illustrate the efficiency of the proposed AOD methodology

    Rapid, Precise, and High-Sensitivity Acquisition of Paleomagnetic and Rock-Magnetic Data: Development of a Low-Noise Automatic Sample Changing System for Superconducting Rock Magnetometers

    Get PDF
    Among Earth sciences, paleomagnetism is particularly linked to the statistics of large sample sets as a matter of historical development and logistical necessity. Because the geomagnetic field varies over timescales relevant to sedimentary deposition and igneous intrusion, while the fidelity of recorded magnetization is modulated by original properties of rock units and by alteration histories, "ideal" paleomagnetic results measure remanent magnetizations of hundreds of samples at dozens of progressive demagnetization levels, accompanied by tests of magnetic composition on representative sister specimens. We present an inexpensive, open source system for automating paleomagnetic and rock magnetic measurements. Using vacuum pick-and-place technology and a quartz-glass sample holder, the system can in one hour measure remanent magnetizations, as weak as a few pAm2, of ~30 specimens in two vertical orientations with measurement errors comparable to those of the best manual systems. The system reduces the number of manual manipulations required per specimen ~8 fold

    Visualization--A method of instruction in the elementary school

    Full text link
    Thesis (M.A.)--Boston Universit

    Measuring information latency

    Get PDF
    Many companies have recently digitized a substantial number of their business processes. It is often the case that some companies store their data on a digital medium and that this data is can be captured and stored in real-time or in a batch process. Measuring the time it takes a system to traverse and process information is of the utmost importance to internal and external stakeholders of the organization. However, it is often difficult for companies to identify information flow and process bottlenecks. In this paper we develop an approach for evaluating the level of companies¿ digitization. We formalize and provide an illustrative example for a model that can facilitate the measurement of information flow latency within organizations and discuss the benefits associated with the model. The proposed latency measure is unique in that it facilitates the measurement of information flow and process latency. The measure is a very important in that it can assist management in improving the most critical business processes in their company. Moreover, an assurance service can be developed in order to increase the trust in the digitization level of business partners. Using the proposed latency measurement model a future assurance service can provide supply chain partners the confidence that their business partners can meet delivery and production schedules accurately and on a timely basis.Muchas empresas han digitalizado recientemente un sustancial número de sus procesos de negocios. Es a menudo el caso de que algunas compañías almacenan su información sobre un medio digital y que esta información puede ser obtenida y almacenada en tiempo real o en un proceso en lotes. Midiendo el tiempo que tarda un sistema para cruzar y procesar información es de suma importancia a inversores internos y externos de la organización. Sin embargo, es a menudo difícil para las empresas identificar flujos de información y los obstáculos del proceso. En este trabajo, desarrollamos una estrategia para evaluar el nivel de digitalización de las empresas. Formalizamos y aportamos un ejemplo ilustrativo para un modelo, que pueda facilitar la medida de la latencia del flujo de la información dentro de las organizaciones, y debatimos los beneficios asociados con dicho modelo. La medida de la latencia propuesta es única en la medida en la que facilita las medidas del flujo de información, y la latencia del proceso. La medida es una muy importante, en el hecho de que ayuda a la dirección a mejorar los procesos comerciales más críticos en su compañía. Además, un servicio de garantía puede ser desarrollado para aumentar la confianza en el nivel de digitalización de los socios comerciales. Usando el modelo de medida de latencia sugerido, un futuro servicio de garantía puede aportar a los socios de la cadena de suministro la confianza que sus socios de negocios puedan cumplir exactamente, y a tiempo con los planes de entrega, y producción

    The Maunakea Spectroscopic Explorer Book 2018

    Full text link
    (Abridged) This is the Maunakea Spectroscopic Explorer 2018 book. It is intended as a concise reference guide to all aspects of the scientific and technical design of MSE, for the international astronomy and engineering communities, and related agencies. The current version is a status report of MSE's science goals and their practical implementation, following the System Conceptual Design Review, held in January 2018. MSE is a planned 10-m class, wide-field, optical and near-infrared facility, designed to enable transformative science, while filling a critical missing gap in the emerging international network of large-scale astronomical facilities. MSE is completely dedicated to multi-object spectroscopy of samples of between thousands and millions of astrophysical objects. It will lead the world in this arena, due to its unique design capabilities: it will boast a large (11.25 m) aperture and wide (1.52 sq. degree) field of view; it will have the capabilities to observe at a wide range of spectral resolutions, from R2500 to R40,000, with massive multiplexing (4332 spectra per exposure, with all spectral resolutions available at all times), and an on-target observing efficiency of more than 80%. MSE will unveil the composition and dynamics of the faint Universe and is designed to excel at precision studies of faint astrophysical phenomena. It will also provide critical follow-up for multi-wavelength imaging surveys, such as those of the Large Synoptic Survey Telescope, Gaia, Euclid, the Wide Field Infrared Survey Telescope, the Square Kilometre Array, and the Next Generation Very Large Array.Comment: 5 chapters, 160 pages, 107 figure

    Pedagogy in diverse secondary school classes: Legacies for higher education

    Get PDF
    As university teachers we find ourselves grappling with the increasingly diverse legacies of students’ prior pedagogic experiences – some of which seem to work against the quality intellectual outcomes now demanded from higher education. In this context, this paper reports a descriptive study of pedagogy created for Chinese students in a mainstream Australian secondary school with a high level of tertiary entry. An influential literature on student learning in higher education has pointed to the constraining effects of bothWestern and Chinese secondary schooling on university students’ learning. In the case of Chinese students who enter Western universities from Western secondary schools, the picture is complicated by research indicating that students of English as a Second Language (ESL) receive even more constraining forms of pedagogy than their native-English-speaking peers. A framework of Bernsteinian sociological concepts and discourse analytic concepts was employed in the study reported here to explore this possibility. Implications are drawn for managing the transition of ESL students to university contexts, and for reflecting on our own responses to linguistic and cultural diversity in the tutorial room

    A knowledge-based system design/information tool

    Get PDF
    The objective of this effort was to develop a Knowledge Capture System (KCS) for the Integrated Test Facility (ITF) at the Dryden Flight Research Facility (DFRF). The DFRF is a NASA Ames Research Center (ARC) facility. This system was used to capture the design and implementation information for NASA's high angle-of-attack research vehicle (HARV), a modified F/A-18A. In particular, the KCS was used to capture specific characteristics of the design of the HARV fly-by-wire (FBW) flight control system (FCS). The KCS utilizes artificial intelligence (AI) knowledge-based system (KBS) technology. The KCS enables the user to capture the following characteristics of automated systems: the system design; the hardware (H/W) design and implementation; the software (S/W) design and implementation; and the utilities (electrical and hydraulic) design and implementation. A generic version of the KCS was developed which can be used to capture the design information for any automated system. The deliverable items for this project consist of the prototype generic KCS and an application, which captures selected design characteristics of the HARV FCS

    Unwind: Interactive Fish Straightening

    Full text link
    The ScanAllFish project is a large-scale effort to scan all the world's 33,100 known species of fishes. It has already generated thousands of volumetric CT scans of fish species which are available on open access platforms such as the Open Science Framework. To achieve a scanning rate required for a project of this magnitude, many specimens are grouped together into a single tube and scanned all at once. The resulting data contain many fish which are often bent and twisted to fit into the scanner. Our system, Unwind, is a novel interactive visualization and processing tool which extracts, unbends, and untwists volumetric images of fish with minimal user interaction. Our approach enables scientists to interactively unwarp these volumes to remove the undesired torque and bending using a piecewise-linear skeleton extracted by averaging isosurfaces of a harmonic function connecting the head and tail of each fish. The result is a volumetric dataset of a individual, straight fish in a canonical pose defined by the marine biologist expert user. We have developed Unwind in collaboration with a team of marine biologists: Our system has been deployed in their labs, and is presently being used for dataset construction, biomechanical analysis, and the generation of figures for scientific publication

    Numerical continuation and bifurcation analysis in aircraft design:an industrial perspective

    Get PDF
    Bifurcation analysis is a powerful method for studying the steady-state nonlinear dynamics of systems. Software tools exist for the numerical continuation of steady-state solutions as parameters of the system are varied. These tools make it possible to generate ‘maps of solutions’ in an efficient way that provide valuable insight into the overall dynamic behaviour of a system and potentially to influence the design process. While this approach has been employed in the military aircraft control community to understand the effectiveness of controllers, the use of bifurcation analysis in the wider aircraft industry is yet limited. This paper reports progress on how bifurcation analysis can play a role as part of the design process for passenger aircraft.</jats:p
    corecore