896 resultados para lean implementation time


Relevância:

40.00% 40.00%

Publicador:

Resumo:

Thesis (Master's)--University of Washington, 2016-06

Relevância:

40.00% 40.00%

Publicador:

Resumo:

Complementing our recent work on subspace wavepacket propagation [Chem. Phys. Lett. 336 (2001) 149], we introduce a Lanczos-based implementation of the Faber polynomial quantum long-time propagator. The original version [J. Chem. Phys. 101 (1994) 10493] implicitly handles non-Hermitian Hamiltonians, that is, those perturbed by imaginary absorbing potentials to handle unwanted reflection effects. However, like many wavepacket propagation schemes, it encounters a bottleneck associated with dense matrix-vector multiplications. Our implementation seeks to reduce the quantity of such costly operations without sacrificing numerical accuracy. For some benchmark scattering problems, our approach compares favourably with the original. (C) 2004 Elsevier B.V. All rights reserved.

Relevância:

40.00% 40.00%

Publicador:

Resumo:

A restricted maximum likelihood analysis applied to an animal model showed no significant differences (P > 0.05) in pH value of the longissimus dorsi measured at 24 h post-mortem (pH24) between high and low lines of Large White pigs selected over 4 years for post-weaning growth rate on restricted feeding. Genetic and phenotypic correlations between pH24 and production and carcass traits were estimated using all performance testing records combined with the pH24 measurements (5.05–7.02) on slaughtered animals. The estimate of heritability for pH24 was moderate (0.29 ± 0.18). Genetic correlations between pH24 and production or carcass composition traits, except for ultrasonic backfat (UBF), were not significantly different from zero. UBF had a moderate, positive genetic correlation with pH24 (0.24 ± 0.33). These estimates of genetic correlations affirmed that selection for increased growth rate on restricted feeding is likely to result in limited changes in pH24 and pork quality since the selection does not put a high emphasis on reduced fatness.

Relevância:

40.00% 40.00%

Publicador:

Resumo:

Communication has become an essential function in our civilization. With the increasing demand for communication channels, it is now necessary to find ways to optimize the use of their bandwidth. One way to achieve this is by transforming the information before it is transmitted. This transformation can be performed by several techniques. One of the newest of these techniques is the use of wavelets. Wavelet transformation refers to the act of breaking down a signal into components called details and trends by using small waveforms that have a zero average in the time domain. After this transformation the data can be compressed by discarding the details, transmitting the trends. In the receiving end, the trends are used to reconstruct the image. In this work, the wavelet used for the transformation of an image will be selected from a library of available bases. The accuracy of the reconstruction, after the details are discarded, is dependent on the wavelets chosen from the wavelet basis library. The system developed in this thesis takes a 2-D image and decomposes it using a wavelet bank. A digital signal processor is used to achieve near real-time performance in this transformation task. A contribution of this thesis project is the development of DSP-based test bed for the future development of new real-time wavelet transformation algorithms.

Relevância:

40.00% 40.00%

Publicador:

Resumo:

In this thesis, novel analog-to-digital and digital-to-analog generalized time-interleaved variable bandpass sigma-delta modulators are designed, analysed, evaluated and implemented that are suitable for high performance data conversion for a broad-spectrum of applications. These generalized time-interleaved variable bandpass sigma-delta modulators can perform noise-shaping for any centre frequency from DC to Nyquist. The proposed topologies are well-suited for Butterworth, Chebyshev, inverse-Chebyshev and elliptical filters, where designers have the flexibility of specifying the centre frequency, bandwidth as well as the passband and stopband attenuation parameters. The application of the time-interleaving approach, in combination with these bandpass loop-filters, not only overcomes the limitations that are associated with conventional and mid-band resonator-based bandpass sigma-delta modulators, but also offers an elegant means to increase the conversion bandwidth, thereby relaxing the need to use faster or higher-order sigma-delta modulators. A step-by-step design technique has been developed for the design of time-interleaved variable bandpass sigma-delta modulators. Using this technique, an assortment of lower- and higher-order single- and multi-path generalized A/D variable bandpass sigma-delta modulators were designed, evaluated and compared in terms of their signal-to-noise ratios, hardware complexity, stability, tonality and sensitivity for ideal and non-ideal topologies. Extensive behavioural-level simulations verified that one of the proposed topologies not only used fewer coefficients but also exhibited greater robustness to non-idealties. Furthermore, second-, fourth- and sixth-order single- and multi-path digital variable bandpass digital sigma-delta modulators are designed using this technique. The mathematical modelling and evaluation of tones caused by the finite wordlengths of these digital multi-path sigmadelta modulators, when excited by sinusoidal input signals, are also derived from first principles and verified using simulation and experimental results. The fourth-order digital variable-band sigma-delta modulator topologies are implemented in VHDL and synthesized on Xilinx® SpartanTM-3 Development Kit using fixed-point arithmetic. Circuit outputs were taken via RS232 connection provided on the FPGA board and evaluated using MATLAB routines developed by the author. These routines included the decimation process as well. The experiments undertaken by the author further validated the design methodology presented in the work. In addition, a novel tunable and reconfigurable second-order variable bandpass sigma-delta modulator has been designed and evaluated at the behavioural-level. This topology offers a flexible set of choices for designers and can operate either in single- or dual-mode enabling multi-band implementations on a single digital variable bandpass sigma-delta modulator. This work is also supported by a novel user-friendly design and evaluation tool that has been developed in MATLAB/Simulink that can speed-up the design, evaluation and comparison of analog and digital single-stage and time-interleaved variable bandpass sigma-delta modulators. This tool enables the user to specify the conversion type, topology, loop-filter type, path number and oversampling ratio.

Relevância:

40.00% 40.00%

Publicador:

Resumo:

Using the NEODAAS-Dundee AVHRR receiving station (Scotland), NEODAAS-Plymouth can provide calibrated brightness temperature data to end users or interim users in near-real time. Between 2000 and 2009 these data were used to undertake volcano hot spot detection, reporting and time-average discharge rate dissemination during effusive crises at Mount Etna and Stromboli (Italy). Data were passed via FTP, within an hour of image generation, to the hot spot detection system maintained at Hawaii Institute of Geophysics and Planetology (HIGP, University of Hawaii at Manoa, Honolulu, USA). Final product generation and quality control were completed manually at HIGP once a day, so as to provide information to onsite monitoring agencies for their incorporation into daily reporting duties to Italian Civil Protection. We here describe the processing and dissemination chain, which was designed so as to provide timely, useable, quality-controlled and relevant information for ‘one voice’ reporting by the responsible monitoring agencies.

Relevância:

40.00% 40.00%

Publicador:

Resumo:

Using the NEODAAS-Dundee AVHRR receiving station (Scotland), NEODAAS-Plymouth can provide calibrated brightness temperature data to end users or interim users in near-real time. Between 2000 and 2009 these data were used to undertake volcano hot spot detection, reporting and time-average discharge rate dissemination during effusive crises at Mount Etna and Stromboli (Italy). Data were passed via FTP, within an hour of image generation, to the hot spot detection system maintained at Hawaii Institute of Geophysics and Planetology (HIGP, University of Hawaii at Manoa, Honolulu, USA). Final product generation and quality control were completed manually at HIGP once a day, so as to provide information to onsite monitoring agencies for their incorporation into daily reporting duties to Italian Civil Protection. We here describe the processing and dissemination chain, which was designed so as to provide timely, useable, quality-controlled and relevant information for ‘one voice’ reporting by the responsible monitoring agencies.

Relevância:

40.00% 40.00%

Publicador:

Resumo:

Increased complexity in large design and manufacturing organisations requires improvements at the operations management (OM)–applied service (AS) interface areas to improve project effectiveness. The aim of this paper is explore the role of Lean in improving the longitudinal efficiency of the OM–AS interface within a large aerospace organisation using Lean principles and boundary spanning theory. The methodology was an exploratory longitudinal case approach including exploratory interviews (n = 21), focus groups (n = 2), facilitated action-research workshops (n = 2) and two trials or experiments using longitudinal data involving both OM and AS personnel working at the interface. The findings draw upon Lean principles and boundary spanning theory to guide and interpret the findings. It was found that misinterpretation, and forced implementation, of OM-based Lean terminology and practice in the OM–AS interface space led to delays and misplaced resources. Rather both OM and AS staff were challenged to develop a cross boundary understanding of Lean-based boundary (knowledge) objects in interpreting OM requests. The longitudinal findings from the experiments showed that the development of Lean Performance measurements and lean Value Stream constructs was more successful when these Lean constructs were treated as boundary (knowledge) objects requiring transformation over time to orchestrate improved effectiveness and in leading to consistent terminology and understanding between the OM–AS boundary spanning team.

Relevância:

40.00% 40.00%

Publicador:

Resumo:

Idag är det vanligt att företagen konkurrerar med produkter som innefattar en fysisk vara som har utvidgats med olika tjänster för att kunna tillfredsställa kundens behov. I takt med detta ökar produkternas komplexitet och högre krav ställs på leverantörerna. Denna utveckling har lett till att många företag som tillverkar produkter med hög variation måste arbeta helt kundorderstyrt för att kunna tillgodose kundernas ökande krav. Företagen som tillverkar dessa komplexa produkter har en tillverkning som karaktäriseras av hög variation och låg volym vilket benämns med förkortningen HVLV. Utmaningen för dessa HVLV-företag ligger i att ha en hög produktmixflexibilitet med så låg resursanvändning som möjligt. För att effektivisera verksamheten har många företag därför intresserat sig för Lean production som har visat sig vara ett framgångsrikt koncept för tillverkande företag runt om i världen som effektiviserat sin produktion. Ett flertal artiklar har uppmärksammat begränsningar vid implementeringen av Lean production i HVLV-miljöer. Artiklar pekar vidare på behovet av ytterligare forskning kring Lean productions applicerbarhet i HVLV-miljöer och detta var uppkomsten till examensarbetets bakgrund och syfte. En fallstudie har genomförts på Tibrokök som är ett företag med en helt kundorderstyrd produktion som kännetecknas av HVLV. Med hjälp av fallstudien syftar examensarbetet till att undersöka om verktygen processkartläggning inkl. tidsstudier och layoutflödesdiagram kan bidra till att skapa förutsättningar för implementering av Lean production i en enskild tillverkningsprocess i en HVLV-miljö. Trots att verktygen har behövt anpassas något så anses de ha varit användbara och bidragande till skapandet av förutsättningar för implementering av Lean production i denna HVLV-miljö. Detta eftersom vi kunde identifiera många orsaker till slöseri samt ta fram ett förslag som skapar effektiviseringar av Tibroköks ytbehandlingsprocess i det framtida läget.

Relevância:

40.00% 40.00%

Publicador:

Resumo:

Esta dissertação foi desenvolvida no âmbito do 2º ano do Mestrado em Engenharia Mecânica – Ramo de Gestão Industrial no Instituto Superior de Engenharia do Porto. Este projeto realizou-se em ambiente industrial, nomeadamente na Tubembal, S.A. uma empresa localizada no concelho da Trofa, distrito do Porto. Esta empresa dedica-se à transformação de papel e comércio de embalagens, produz tubos e cantoneiras de cartão e é atualmente a maior empresa do sector na Península Ibérica. Esta dissertação baseia-se na aplicação de ferramentas Lean, numa perspetiva de melhoria de um ambiente produtivo industrial, melhorando o desempenho dos processos existentes e consequentemente a produtividade da empresa em estudo, com o objetivo de a tornar mais competitiva num ambiente global. A metodologia Lean tem como principal objetivo a eliminação de desperdício em toda a cadeia de valor e neste sentido surge como fundamental numa cultura de melhoria contínua e focalização no cliente, que se pretende instalar nesta empresa. Foi realizada uma análise profunda a toda a cadeia de valor como forma de identificar os maiores desperdícios e posteriormente apresentadas medidas para combater estes mesmos desperdícios, podendo assim reduzir custos. No projeto de melhoria apresentado à organização constam como principais ações, a implementação da metodologia 5S’s como ferramenta essencial para mudança de hábitos dos funcionários e integração e envolvimento de todos num mesmo projeto comum, na busca da melhoria contínua. Procedeu-se ainda à simulação de algumas propostas de reorganização do layout de forma a encontrar aquela que minimizasse os custos com movimentações e garantisse um fluxo controlado e em segurança dos produtos e pessoas dentro da fábrica. As propostas apresentadas mostram que a reorganização do layout da fábrica pode trazer ganhos significativos para a empresa, redução direta no tempo perdido em deslocações e maior disponibilidade dos meios e consequente direta redução dos custos. Todas as propostas apresentadas visam a adaptação da empresa a um modelo mais dinâmico de negócio, capaz de responder rápida e eficazmente aos seus clientes, adaptando-se ao mercado e garantindo a sua sustentabilidade num futuro próximo.

Relevância:

40.00% 40.00%

Publicador:

Resumo:

New generation embedded systems demand high performance, efficiency and flexibility. Reconfigurable hardware can provide all these features. However the costly reconfiguration process and the lack of management support have prevented a broader use of these resources. To solve these issues we have developed a scheduler that deals with task-graphs at run-time, steering its execution in the reconfigurable resources while carrying out both prefetch and replacement techniques that cooperate to hide most of the reconfiguration delays. In our scheduling environment task-graphs are analyzed at design-time to extract useful information. This information is used at run-time to obtain near-optimal schedules, escaping from local-optimum decisions, while only carrying out simple computations. Moreover, we have developed a hardware implementation of the scheduler that applies all the optimization techniques while introducing a delay of only a few clock cycles. In the experiments our scheduler clearly outperforms conventional run-time schedulers based on As-Soon-As-Possible techniques. In addition, our replacement policy, specially designed for reconfigurable systems, achieves almost optimal results both regarding reuse and performance.

Relevância:

40.00% 40.00%

Publicador:

Resumo:

This thesis presents a system for visually analyzing the electromagnetic fields of the electrical machines in the energy conversion laboratory. The system basically utilizes the finite element method to achieve a real-time effect in the analysis of electrical machines during hands-on experimentation. The system developed is a tool to support the student's understanding of the electromagnetic field by calculating performance measures and operational concepts pertaining to the practical study of electrical machines. Energy conversion courses are fundamental in electrical engineering. The laboratory is conducted oriented to facilitate the practical application of the theory presented in class, enabling the student to use electromagnetic field solutions obtained numerically to calculate performance measures and operating characteristics. Laboratory experiments are utilized to help the students understand the electromagnetic concepts by the use of this visual and interactive analysis system. In this system, this understanding is accomplished while hands-on experimentation takes place in real-time.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

This research work analyses techniques for implementing a cell-centred finite-volume time-domain (ccFV-TD) computational methodology for the purpose of studying microwave heating. Various state-of-the-art spatial and temporal discretisation methods employed to solve Maxwell's equations on multidimensional structured grid networks are investigated, and the dispersive and dissipative errors inherent in those techniques examined. Both staggered and unstaggered grid approaches are considered. Upwind schemes using a Riemann solver and intensity vector splitting are studied and evaluated. Staggered and unstaggered Leapfrog and Runge-Kutta time integration methods are analysed in terms of phase and amplitude error to identify which method is the most accurate and efficient for simulating microwave heating processes. The implementation and migration of typical electromagnetic boundary conditions. from staggered in space to cell-centred approaches also is deliberated. In particular, an existing perfectly matched layer absorbing boundary methodology is adapted to formulate a new cell-centred boundary implementation for the ccFV-TD solvers. Finally for microwave heating purposes, a comparison of analytical and numerical results for standard case studies in rectangular waveguides allows the accuracy of the developed methods to be assessed.