114,211 research outputs found
Modeling and control of a plastic film manufacturing web process
This paper is concerned with the modelling of aplastic film manufacturing process and the development and implementation of a model-based Cross-Directional (CD) controller. The model is derived from first-principles and some empirical relationships. The final validated nonlinear model could provide a useful off-line platform for developing control and monitoring algorithms.A new controller is designed which has a similar structureto that of Internal Model Control (IMC) with the addition ofan observer whose gain is designed to minimise process andmodel mis-match. The observer gain is obtained by solving amulti-objective optimisation problem through the application of a genetic algorithm. The controller is applied to the nonlinear model and simulation results are presented demonstrating improvements that can be achieved by the proposed controller over two existing CD controllers
Investigation of marmoset hybrids (Cebuella pygmaea x Callithrix jacchus) and related Callitrichinae (Platyrrhini) by cross-species chromosome painting and comparative genomic hybridization
We report on the cytogenetics of twin offspring from an interspecies cross in marmosets (Callitrichinae, Platyrrhini), resulting from a pairing between a female Common marmoset (Callithrix jacchus, 2n = 46) and a male Pygmy marmoset (Cebuella pygmaea, 2n = 44). We analyzed their karyotypes by multi-directional chromosome painting employing human, Saguinus oedipus and Lagothrix lagothricha chromosome-specific probes. Both hybrid individuals had a karyotype with a diploid chromosome number of 2n = 45. As a complementary tool, interspecies comparative genomic hybridization (iCGH) was performed in order to screen for genomic imbalances between the hybrids and their parental species, and between Callithrix argentata and S. oedipus, respectively. Copyright (C) 2005 S. Karger AG, Basel
Cutting tool tracking and recognition based on infrared and visual imaging systems using principal component analysis (PCA) and discrete wavelet transform (DWT) combined with neural networks
The implementation of computerised condition monitoring systems for the detection cutting tools’ correct installation and fault diagnosis is of a high importance in modern manufacturing industries. The primary function of a condition monitoring system is to check the existence of the tool before starting any machining process and ensure its health during operation. The aim of this study is to assess the detection of the existence of the tool in the spindle and its health (i.e. normal or broken) using
infrared and vision systems as a non-contact methodology. The application of Principal Component Analysis (PCA) and Discrete Wavelet Transform (DWT) combined with neural networks are investigated using both types of data in order to establish an effective and reliable novel software program for tool tracking and health recognition. Infrared and visual cameras are used to locate and track the cutting tool during the machining process using a suitable analysis and image processing algorithms. The capabilities of PCA and Discrete Wavelet Transform (DWT) combined with neural networks are investigated in recognising the tool’s condition by comparing the characteristics of the tool to those of known conditions in the training set. The experimental results have shown high performance when using the infrared data in comparison to visual images for the selected image and signal processing algorithms
Assembly and Disassembly Planning by using Fuzzy Logic & Genetic Algorithms
The authors propose the implementation of hybrid Fuzzy Logic-Genetic
Algorithm (FL-GA) methodology to plan the automatic assembly and disassembly
sequence of products. The GA-Fuzzy Logic approach is implemented onto two
levels. The first level of hybridization consists of the development of a Fuzzy
controller for the parameters of an assembly or disassembly planner based on
GAs. This controller acts on mutation probability and crossover rate in order
to adapt their values dynamically while the algorithm runs. The second level
consists of the identification of theoptimal assembly or disassembly sequence
by a Fuzzy function, in order to obtain a closer control of the technological
knowledge of the assembly/disassembly process. Two case studies were analyzed
in order to test the efficiency of the Fuzzy-GA methodologies
Machining stability and machine tool dynamics
Machining is a common manufacturing process in industry due to its high flexibility and ability to produce parts which excellent quality. The productivity and quality in machining operations can be limited by several process constraints one of which is the self-excited chatter vibrations. Under certain conditions, the process may become unstable yielding oscillations with high amplitudes which result in poor surface finish and damage to the cutting tool, part and the machine tool itself. Stability analysis of the dynamic cutting process can be used to determine chatter-free machining conditions with high material removal rate. Since chatter is a result of the dynamic interactions between the process and the structures both cutting and machine tool dynamics are important elements of the stability analysis. In this paper, methods developed for stability analysis of cutting processes and machine tool dynamics will be presented. Implications of these methods in the selection of process parameters and machine tool design will be also discussed with example applications
Role and Discipline Relationships in a Transdisciplinary Biomedical Team: Structuration, Values Override and Context Scaffolding
Though accepted that "team science" is needed to tackle and conquer the
health problems that are plaguing our society significant empirical evidence of
team mechanisms and functional dynamics is still lacking in abundance. Through
grounded methods the relationship between scientific disciplines and team roles
was observed in a United States National Institutes of Health-funded (NIH)
research consortium. Interviews and the Organizational Culture Assessment
Instrument (OCAI) were employed.. Findings show strong role and discipline
idiosyncrasies that when viewed separately provide different insights into team
functioning and change receptivity. When considered simultaneously,
value-latent characteristics emerged showing self-perceived contributions to
the team. This micro/meso analysis suggests that individual participation in
team level interactions can inform the structuration of roles and disciplines
in an attempt to tackle macro level problems.Comment: Presented at COINs13 Conference, Chile, 2013 (arxiv:1308.1028
Towards an Intelligent Workflow Designer based on the Reuse of Workflow Patterns
In order to perform process-aware information systems we need sophisticated methods and concepts for designing and modeling processes. Recently, research on workflow patterns has emerged in order to increase the reuse of recurring workflow structures. However, current workflow modeling tools do not provide functionalities that enable users to define, query, and reuse workflow patterns properly. In this paper we gather a suite for both process modeling and normalization based on workflow patterns reuse. This suite must be used in the extension of some workflow design tool. The suite comprises components for the design of processes
from both legacy systems and process modeling
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