光热-光电集成型太阳能孵化机设计

传统孵化机局限性很大,一旦停电,胚胎将会死亡,严重影响孵化效率。为了克服上述缺点,提出一种以太阳能光热为主、光电为辅的孵化机设计方案。采用集热管加热太阳能热水器中的水,并送至孵化箱内部的铜制“暖气片”;通过控制器控制电磁阀、通风风扇、加湿管等保持孵化箱内适宜的孵化环境;“暖气片”中的水温下降后再由水管排至冷水箱中,并用泵把冷水箱中的水打入热水器,形成对水的循环利用;将太阳能电池板发出的电储存在蓄电池里面,用来为控制器及灯泡等供电,或在阴雨天气为孵化机的加热片加温。该孵化机符合国家新能源发展政策,节能环保。     

面向装备制造业的开放式技术集成创新模式——以大连机床集团为例

针对装备制造企业的自主创新能力提升问题,以大连机床集团为例,分析了大连机床集团开放式技术集成创新的模式,研究表明：企业具有较高的技术监测、消化吸收以及技术集成能力,能够根据组织情景的变化利用已有的技术存量,并在装备产品开发的系统集成层面学习建构知识,提高企业自身产品建构能力,从而实现开发具有主要知识产权高端装备产品的重要突破.     

半主动动力吸振镗杆系统的颤振抑制机理

深孔镗削过程中,针对影响工件加工精度和表面质量的颤振现象,建立单自由度切削颤振系统的动力学模型,利用谐波平衡法求得机床主轴转速与极限切削宽度的关系式,并绘制了机床主轴转速与极限切削宽度的稳定性图,结合半主动动力吸振镗杆刚度和阻尼系数的可控性,分析了机床结构刚度及阻尼系数大小对颤振抑制的影响。研究结果表明:机床颤振频率随着主轴转速呈分段线性变化,增大机床结构的刚度和阻尼,系统的稳定性区域在一定范围内相应的增大。为今后进行半主动动力吸振镗杆具体模型的建立和相关参数的选取提供了理论依据,具有实际意义。     

数字化控制系统人机交互的复杂性对人因失误的影响研究

根据现场调研和视频观察,对数字化控制系统与传统的模拟控制系统进行了对比分析,发现数字化控制系统人机交互具有操纵员角色转变、认知负荷大、硬控制向软控制转变、人机界面交互更加丰富的特征.通过人机交互复杂性的关键因子,即操纵员因素、任务因素、界面管理因素以及操作因素,分析了它们对人因失误的影响,以期为降低人机交互的复杂性提供理论支持.     

What do refugees want? Reading refugee lip-sewing protests through a critical lens

Through a close reading of lip-sewing protests by refugees over the past two decades, this article develops a theoretical framework for understanding lip sewing as a form of protest and political agency. I consider various lip-sewing protests by refugees and the strategic use of speechlessness and corporeality in these protests to uncover the conditions in which contemporary refugees are imbricated. I argue that this unusual form of protest, as well as the demands that protesters make on states and international institutions through dissensus, reflects the existence of a new kind of refugee that has emerged in response to the contemporary refugee management system that criminalizes displacement.     

基于WT-SVM-非参数方法的农业保险费率研究--以山东省棉花保险为例

构建了 WT-SVM-非参数方法农作物保险费率厘定模型,即首先采用小波分析法(WT)获得已知年份作物趋势单产;接着用支持向量机(SVM)对所得趋势单产进行拟合并预测,得到未来所保年份作物趋势单产;再接着运用非参数核密度法拟合作物损失概率分布;最后根据单产分布模型法计算作物保险费率.以山东省棉花保险为例验证模型的有效性,结果表明:WT-SVM-非参数方法能够有效提高农作物保险费率厘定精度;山东省目前收取的棉花保险费率稍低.     

贵金属期货价格预测方法及实证研究

本文融合了二次分解与极限学习机的优势,提出了VMD-Res.-EEMD-ELM贵金属期货价格预测模型,选择变分模态分解(VMD)作为主要的分解技术,生成模态分量序列(VMFi)和残差序列(Res.),采用集合经验模态分解(EEMD)对残差序列进行二次分解,并使用具有良好泛化能力的极限学习机(ELM)对各分量进行预测,最后叠加各模态分量和残差的预测值形成收益率的最终预测结果。所提出的模型不仅充分发挥了二次分解技术的优势,而且解决了传统变分模态分解组合预测模型未考虑残差影响因素的问题。实证研究表明,本文所提出的组合模型能够全面捕捉黄金、白银期货价格日收益率序列的特征,方向性预测准确率分别为83.33%和93.33%,误差指标MAE分别为0.15和0.11,经比较本文所提出的模型具有良好的预测性能。     

蠕动式点胶机的精确点胶研究

为了改善传统点胶机不易控制流量的问题,在分析蠕动泵的基础上,建立蠕动泵的模型并进行理论流量的推导;然后对蠕动泵的步进电机进行分析,提出采用ATmega2560微控制器外接驱动器A4988细分驱动技术方案,对蠕动泵步进电机控制系统进行设计;对单个点胶过程提出采用S型曲线规划Z轴的运动,实验证实采用蠕动泵进行点胶达到了良好的点胶效果,本研究提高了点胶质量。     

On kernel machine learning for propensity score estimation under complex confounding structures

Post marketing data offer rich information and cost-effective resources for physicians and policy-makers to address some critical scientific questions in clinical practice. However, the complex confounding structures (e.g., nonlinear and nonadditive interactions) embedded in these observational data often pose major analytical challenges for proper analysis to draw valid conclusions. Furthermore, often made available as electronic health records (EHRs), these data are usually massive with hundreds of thousands observational records, which introduce additional computational challenges. In this paper, for comparative effectiveness analysis, we propose a statistically robust yet computationally efficient propensity score (PS) approach to adjust for the complex confounding structures. Specifically, we propose a kernel-based machine learning method for flexibly and robustly PS modeling to obtain valid PS estimation from observational data with complex confounding structures. The estimated propensity score is then used in the second stage analysis to obtain the consistent average treatment effect estimate. An empirical variance estimator based on the bootstrap is adopted. A split-and-merge algorithm is further developed to reduce the computational workload of the proposed method for big data, and to obtain a valid variance estimator of the average treatment effect estimate as a by-product. As shown by extensive numerical studies and an application to postoperative pain EHR data comparative effectiveness analysis, the proposed approach consistently outperforms other competing methods, demonstrating its practical utility.     

Measures of backtracking and bi-directional flow in one dimensional machine location problems

In many modern manufacturing settings, management simplifies the workflow of jobs to the greatest extent possible by avoiding a job-shop structure in favour of a generalized flow line (GFL) in which all jobs flow in a single direction (Conway et al., 1967, Theory of Scheduling (Addison-Wcsley)). Heuristics may be used to assign machines to appropriate locations in the attempt to achieve a GFL. Materials that must be transported upstream in a production line are said to ‘backtrack’. Since no backtracking occurs in a GFL, the relative amount of backtracking that does occur is an indication of the degree to which the ideal (and most productive) case is achieved. Several measures of the backtracking of materials are developed in this paper to assess the degree to which a configuration approaches the GFL. The measure for backtracking is extended to bi-directional flow problems which may occur when a GFL is not achievable because of the job routing.