47,003 research outputs found
Octree-based production of near net shape components
Near net shape (NNS) manufacturing refers to the production of products that require a finishing operation of some kind. NNS manufacturing is important because it enables a significant reduction in: machining work, raw material usage, production time, and energy consumption. This paper presents an integrated system for the production of near net shape components based on the Octree decomposition of 3-D models. The Octree representation is used to automatically decompose and approximate the 3-D models, and to generate the robot instructions required to create assemblies of blocks secured by adhesive. Not only is the system capable of producing shapes of variable precision and complexity (including overhanging or reentrant shapes) from a variety of materials, but it also requires no production tooling (e.g., molds, dies, jigs, or fixtures). This paper details how a number of well-known Octree algorithms for subdivision, neighbor findings, and tree traversal have been modified to support this novel application. This paper ends by reporting the construction of two mechanical components in the prototype cell, and discussing the overall feasibility of the system
The design co-ordination framework : key elements for effective product development
This paper proposes a Design Co-ordination Framework (DCF) i.e. a concept for an ideal DC system with the abilities to support co-ordination of various complex aspects of product development. A set of frames, modelling key elements of co-ordination, which reflect the states of design, plans, organisation, allocations, tasks etc. during the design process, has been identified. Each frame is explained and the co-ordination, i.e. the management of the links between these frames, is presented, based upon characteristic DC situations in industry. It is concluded that while the DCF provides a basis for our research efforts into enhancing the product development process there is still considerable work and development required before it can adequately reflect and support Design Co-ordination
Virtual bloXing - assembly rapid prototyping for near net shapes
Virtual reality (VR) provides another dimension to many engineering applications. Its immersive and interactive nature allows an intuitive approach to study both cognitive activities and performance evaluation. Market competitiveness means having products meet form, fit and function quickly. Rapid Prototyping and Manufacturing (RP&M) technologies are increasingly being applied to produce functional prototypes and the direct manufacturing of small components. Despite its flexibility, these systems have common drawbacks such as slow build rates, a limited number of build axes (typically one) and the need for post processing. This paper presents a Virtual Assembly Rapid Prototyping (VARP) project which involves evaluating cognitive activities in assembly tasks based on the adoption of immersive virtual reality along with a novel nonlayered rapid prototyping for near net shape (NNS) manufacturing of components. It is envisaged that this integrated project will facilitate a better understanding of design for manufacture and assembly by utilising equivalent scale digital and physical prototyping in one rapid prototyping system. The state of the art of the VARP project is also presented in this paper
Innovation Activity and Competitiveness of Manufacturing Divisions in Poland
In the research were used statistical data of Central Statistical Office showing amounts of particular types of outlays divided into particular manufacturing divisions (section D, the Polish Classification of Activities) in the period 1999-2008. the analysis was conducted by means of panel models, where the basic period is calendar year, and the objects are manufacturing divisions on two-digit level of aggregation.W badaniu wykorzystano publikowane dane statystyczne Głównego Urzędu Statystycznego o wysokości poszczególnych typów nakładów w podziale na poszczególne działy przetwórstwa przemysłowego (sekcja D PKD) w latach 1999-2008. Analiza została przeprowadzona z wykorzystaniem modeli panelowych, gdzie podstawowym okresem jest rok kalendarzowy, zaś obiektami są działy przetwórstwa przemysłowego na dwucyfrowym poziomie agregacji
Virtual assembly rapid prototyping of near net shapes
Virtual reality (VR) provides another dimension to many engineering applications. Its immersive and interactive nature allows an intuitive approach to study both cognitive activities and performance evaluation. Market competitiveness means having products meet form, fit and function quickly. Rapid Prototyping and Manufacturing (RP&M) technologies are increasingly being applied to produce functional prototypes and the direct manufacturing of small components. Despite its flexibility, these systems have common drawbacks such as slow build rates, a limited number of build axes (typically one) and the need for post processing. This paper presents a Virtual Assembly Rapid Prototyping (VARP) project which involves evaluating cognitive activities in assembly tasks based on the adoption of immersive virtual reality along with a novel non-layered rapid prototyping for near net shape (NNS) manufacturing of components. It is envisaged that this integrated project will facilitate a better understanding of design for manufacture and assembly by utilising equivalent scale digital and physical prototyping in one rapid prototyping system. The state of the art of the VARP project is also presented in this paper
Global supply chains of high value low volume products
Imperial Users onl
Topological structures in the equities market network
We present a new method for articulating scale-dependent topological
descriptions of the network structure inherent in many complex systems. The
technique is based on "Partition Decoupled Null Models,'' a new class of null
models that incorporate the interaction of clustered partitions into a random
model and generalize the Gaussian ensemble. As an application we analyze a
correlation matrix derived from four years of close prices of equities in the
NYSE and NASDAQ. In this example we expose (1) a natural structure composed of
two interacting partitions of the market that both agrees with and generalizes
standard notions of scale (eg., sector and industry) and (2) structure in the
first partition that is a topological manifestation of a well-known pattern of
capital flow called "sector rotation.'' Our approach gives rise to a natural
form of multiresolution analysis of the underlying time series that naturally
decomposes the basic data in terms of the effects of the different scales at
which it clusters. The equities market is a prototypical complex system and we
expect that our approach will be of use in understanding a broad class of
complex systems in which correlation structures are resident.Comment: 17 pages, 4 figures, 3 table
Configurational Information as Potentially Negative Entropy: The Triple Helix Model
Configurational information is generated when three or more sources of
variance interact. The variations not only disturb each other relationally, but
by selecting upon each other, they are also positioned in a configuration. A
configuration can be stabilized and/or globalized. Different stabilizations can
be considered as second-order variation, and globalization as a second-order
selection. The positive manifestations and the negative selections operate upon
one another by adding and reducing uncertainty, respectively. Reduction of
uncertainty in a configuration can be measured in bits of information. The
variables can also be considered as dimensions of the probabilistic entropy in
the system(s) under study. The configurational information then provides us
with a measure of synergy within a complex system. For example, the knowledge
base of an economy can be considered as such a synergy in the otherwise virtual
(that is, fourth) dimension of a regime
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