907 resultados para mixed-model assembly line


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Purpose Encouraging office workers to 'sit less and move more' encompasses two public health priorities. However, there is little evidence on the effectiveness of workplace interventions for reducing sitting, even less about the longer term effects of such interventions and still less on dual-focused interventions. This study assessed the short and mid-term impacts of a workplace web-based intervention (Walk@WorkSpain, W@WS; 2010-11) on self-reported sitting time, step counts and physical risk factors (waist circumference, BMI, blood pressure) for chronic disease. Methods Employees at six Spanish university campuses (n=264; 42 +/- 10 years; 171 female) were randomly assigned by worksite and campus to an Intervention (used W@WS; n=129; 87 female) or a Comparison group (maintained normal behavior; n=135; 84 female). This phased, 19-week program aimed to decrease occupational sitting time through increased incidental movement and short walks. A linear mixed model assessed changes in outcome measures between the baseline, ramping (8 weeks), maintenance (11 weeks) and follow-up (two months) phases for Intervention versus Comparison groups. Results A significant 2 (group) x 2 (program phases) interaction was found for self-reported occupational sitting (F[3]=7.97, p=0.046), daily step counts (F[3]=15.68, p=0.0013) and waist circumference (F[3]=11.67, p=0.0086). The Intervention group decreased minutes of daily occupational sitting while also increasing step counts from baseline (446 +/- 126; 8,862 +/- 2,475) through ramping (+425 +/- 120; 9,345 +/- 2,435), maintenance (+422 +/- 123; 9,638 +/- 3,131) and follow-up (+414 +/- 129; 9,786 +/- 3,205). In the Comparison group, compared to baseline (404 +/- 106), sitting time remained unchanged through ramping and maintenance, but decreased at follow-up (-388 +/- 120), while step counts diminished across all phases. The Intervention group significantly reduced waist circumference by 2.1cms from baseline to follow-up while the Comparison group reduced waist circumference by 1.3cms over the same period. Conclusions W@WSis a feasible and effective evidence-based intervention that can be successfully deployed with sedentary employees to elicit sustained changes on "sitting less and moving more".

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In this paper we present livestock breeding developments that could be taken into consideration in the genetic improvement of farmed aquaculture species, especially in freshwater fish. Firstly, the current breeding objective in aquatic species has focused almost exclusively on the improvement of body weight at harvest or on growth related traits. This is unlikely to be sufficient to meet the future needs of the aquaculture industry. To meet future demands breeding programs will most likely have to include additional traits, such as fitness related ones (survival, disease resistance), feed efficiency, or flesh quality, rather than only growth performance. In order to select for a multi-trait breeding objective, genetic variation in traits of interest and the genetic relationships among them need to be estimated. In addition, economic values for these traits will be required. Generally, there is a paucity of data on variable and fixed production costs in aquaculture, and this could be a major constraint in the further expansion of the breeding objectives. Secondly, genetic evaluation systems using the restricted maximum likelihood method (REML) and best linear unbiased prediction (BLUP) in a framework of mixed model methodology could be widely adopted to replace the more commonly used method of mass selection based on phenotypic performance. The BLUP method increases the accuracy of selection and also allows the management of inbreeding and estimation of genetic trends. BLUP is an improvement over the classic selection index approach, which was used in the success story of the genetically improved farmed tilapia (GIFT) in the Philippines, with genetic gains from 10 to 20 per cent per generation of selection. In parallel with BLUP, optimal genetic contribution theory can be applied to maximize genetic gain while constraining inbreeding in the long run in selection programs. Thirdly, by using advanced statistical methods, genetic selection can be carried out not only at the nucleus level but also in lower tiers of the pyramid breeding structure. Large scale across population genetic evaluation through genetic connectedness using cryopreserved sperm enables the comparison and ranking of genetic merit of all animals across populations, countries or years, and thus the genetically superior brood stock can be identified and widely used and exchanged to increase the rate of genetic progress in the population as a whole. It is concluded that sound genetic programs need to be established for aquaculture species. In addition to being very effective, fully pedigreed breeding programs would also enable the exploration of possibilities of integrating molecular markers (e.g., genetic tagging using DNA fingerprinting, marker (gene) assisted selection) and reproductive technologies such as in-vitro fertilization using cryopreserved spermatozoa.

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介绍了NS2 2 5电动机起动器自动检测与校验生产线 ,指出低压电器产品的自动化生产及其检测是生产企业面临严重课题。自动化生产线充分利用计算机技术及其网络技术 ,实现工厂无人自动化生产 ,它充分利用现代检测技术 ,尤其是激光技术 ,解决生产中测量与标记问题。

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巡检机器人在越障时,需要完成机器人手臂的准确抓线控制.结合输电线的几何特征和摄像机成像原理,提出了一种基于单摄像机的立体视觉方法来确定输电线的位置和姿态.基于该定位方法及视觉伺服理论,建立机械手抓线伺服控制模型.利用自行研制的巡检机器人进行了视觉伺服抓线实验;实验结果验证了该方法的有效性.

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为了克服传统装配线的不足,在基于功能对象的产品族建模基础上,提出了主干线和装配模块相结合的可重构装配系统开放式组织结构。这种分形相似的组织结构具有能力柔性、鲁棒性、功能扩展能力等特点,并能通过模块的局部调整快速响应市场的需求。利用网络法,针对鲁棒性和增容性问题,提出了相应的重构优化算法。

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以某汽车变速箱装配生产线制造系统为背景,应用多Agent制造及Holon制造模式改造传统装配生产线以提升其柔性与重构能力·针对基于agent与holon混合思想的可重构装配生产线的基础框架与实现等理论提供分析验证环境,提出应用数字制造技术构建面向可重构装配线的数字仿真验证平台·在分析面向重构装配线的仿真平台功能特征的基础上,构建了数字仿真验证平台的框架·研究了仿真平台开发中的系统集成、可视化仿真、可重构装配线性能分析等关键技术,最后给出了仿真平台的实例系统·

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以大批量制造的生产线制造系统为背景,研究基于agent与holon智能制造思想体系的可重构生产线制造系统实现技术,以提高生产线柔性与可重构能力为目标·深入分析了多agent制造及holonic制造模式体系下智能单元自主决策、协商合作在制造系统环境中的实现与运行机制,在以机械加工线和装配线为代表的不同的工程实际背景与应用环境下该思想体系目前的具体应用情况与实现技术·指出该思想体系面向具体工程背景的有效实施应用是理论研究的关键·最后以某汽车变速器装配生产线制造系统为应用实例,从其规划设计与运行角度,分析了可重构生产线系统的框架设计及具体实现技术与方法·

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针对混装配线设计这一有约束的多目标优化问题,建立了数学模型。将基于Pareto的解的分级方法与Lp-范数形式的非线性机制相组合,构建了基于遗传退火算法多目标优化方法。重点阐述了个体编码、染色体检修、多目标处理机制等关键技术。设计了算法流程图,并开发了优化程序。该方法克服了加权和方法的不足,用模拟退火改善了遗传算法全局寻优性能。计算实例表明,随着迭代次数的增加,每代的非受控点逐渐收敛于Pareto最优边界,是一种混装线设计多目标优化的新方法。

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研究当前国内外变速箱试验系统的特点,基于现代汽车变速箱生产信息化、网络化和柔性化的要求,依托某变速箱装配线项目,针对其试验环线,提出一种具有并行结构的变速箱自动试验环线,并设计基于Device Net的控制系统,探究试验环线的智能控制。该系统已经进入实际应用,可较好地完成变速箱的性能检测以及试验后的数据分析。

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本文介绍了一种新型涂胶机控制系统的设计,详细描述了系统的原理和硬件功能。涂胶机是汽车变速箱装配流水线上最重要的部分之一。该机除具有自动涂胶功能、自动检测报警功能外,还能与装配管理系统联网,实现网络化管理与控制功能。整个系统采用运动控制器、伺服电机等控制部件,为变速箱涂胶提供了安全可靠的质量保证。

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本文介绍了目前第一条完全由国内生产的全自动托辊装配线及其制造信息系统。该套装系统除具有较高的自动化程度外,还充分利用先进的伺服控制技术,采用先进的SIMOTION运动控制系统,实现了托辊产品装配的柔性化。同时在软件及信息管理方面充分考虑到先进制造管理的理念,为企业的MES系统及管理信息系统的实施和升级提供了充分的接口,从而打造出一条具有较高科技含量和先进性的自动装配线。

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文章介绍了一种新型汽车变速箱压装机控制系统的设计,对系统的硬件组态及控制功能作了主要描述。汽车变速箱压装机是汽车变速箱装配流水线上的一台机电一体化专用自动装配设备,该机除具有自动压装功能、自动检测报警功能外,还能与装配管理系统联网,实现网络化管理与控制功能。整个系统采用了SLC500可编程控制器、触摸屏、安全光幕控制器等控制部件,为机床提供了安全可靠的装配质量保证。

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托辊在国民经济的各行各业扮演着十分重要的角色,尤其在矿业生产的输送过程中,托辊更是发挥着巨大的作用。本项目旨在为托辊的自动化装配线提供整套控制执行系统。本文根据沈阳机床集团所提出的装配线控制要求,在查阅大量相关文献基础上,分析了托辊装配的整个工艺过程,结合先进制造的理念和技术,研究设计出包括制造过程底层信息系统在内的装配线控制系统。本文主要完成了以下研究工作及相关的创新性成果: 系统的供配电设计。根据设备的配电要求及相关规范,对整套控制系统的供配电进行合理的设计。 整条装配线的协调控制及信息系统设计与实现。结合目前广泛采用的工业现场总线技术,设计了整套分层控制及信息系统。整套系统分为三层,在顶层设计有监控系统,该系统通过以太网与下层的单台机床控制器进行信息互换。通过OPC技术将底层控制器采集到的现场信息在上位机上以友好的图文界面显示出来,供操作人员监控。同时还将每台机床的相关信息及以往报警历史按时间进行归档,形成现场装配过程信息备份,供上层的分析与决策系统使用。 现场每台机床采用独立的现场控制器进行控制。因为整条装配线被设计定位为柔性装配线,所以在机床控制上采用了伺服控制技术,以实现针对不同装配产品型号对托辊的支撑及夹具进行准确定位。控制器采用集逻辑、工艺、伺服控制于一体的西门子SIMOTION控制器。该控制器完成整个机床的动作及工艺控制,同时在现场每台机床控制器都配备一个触摸屏作为现场级人机界面,供机床现场调试和人机交互之用。 论文从整体上阐述了装配线控制系统的整体架构,并结合在线检测机床对机床的控制进行了讨论,从多方面体现出该控制及信息系统的完整性和先进性。 该项目开发的托辊装配线控制及信息系统旨在实现托辊安全、快速地自动化装配。并以单台机床单元控制器为主体通过现场总线技术为上层信息管理系统提供信息接口,为整条线的管理功能智能化扩展提供一个良好的平台。

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Sk?t, L., Humphreys, J., Humphreys, M. O., Thorogood, D., Gallagher, J. A., Sanderson, R., Armstead, I. P., Thomas, I. D. (2007). Association of candidate genes with flowering time and water-soluble carbohydrate content in Lolium perenne (L.). Genetics, 177 (1), 535-547. Sponsorship: BBSRC RAE2008

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In 1966, Roy Geary, Director of the ESRI, noted “the absence of any kind of import and export statistics for regions is a grave lacuna” and further noted that if regional analyses were to be developed then regional Input-Output Tables must be put on the “regular statistical assembly line”. Forty-five years later, the lacuna lamented by Geary still exists and remains the most significant challenge to the construction of regional Input-Output Tables in Ireland. The continued paucity of sufficient regional data to compile effective regional Supply and Use and Input-Output Tables has retarded the capacity to construct sound regional economic models and provide a robust evidence base with which to formulate and assess regional policy. This study makes a first step towards addressing this gap by presenting the first set of fully integrated, symmetric, Supply and Use and domestic Input-Output Tables compiled for the NUTS 2 regions in Ireland: The Border, Midland and Western region and the Southern & Eastern region. These tables are general purpose in nature and are consistent fully with the official national Supply & Use and Input-Output Tables, and the regional accounts. The tables are constructed using a survey-based or bottom-up approach rather than employing modelling techniques, yielding more robust and credible tables. These tables are used to present a descriptive statistical analysis of the two administrative NUTS 2 regions in Ireland, drawing particular attention to the underlying structural differences of regional trade balances and composition of Gross Value Added in those regions. By deriving regional employment multipliers, Domestic Demand Employment matrices are constructed to quantify and illustrate the supply chain impact on employment. In the final part of the study, the predictive capability of the Input-Output framework is tested over two time periods. For both periods, the static Leontief production function assumptions are relaxed to allow for labour productivity. Comparative results from this experiment are presented.