基于fastText算法的行业分类技术

随着中国经济的高速发展和技术创新能力的不断提升,高效的组织、分类信息是提供个性化行业管理和跟踪分析的基础。根据行业信息特点和发展规律,提出了一种基于fastText算法的行业分类模型。首先,构建行业分类关键词库,通过特征词库进行分词和权重计算。然后,构建分类器模型,实现中文行业的自动分类。最后,实验选取了80 000个包含企业经营范围、企业信息、舆论信息的测试文档,结果表明,所提模型结果高于Bayes、决策树、KNN等分类算法,取得了较好的应用效果。      

民机自然层流机翼研究进展

新世纪航空市场对能耗、噪音等限制性要求继续加强,新一代民用飞机需要在气动减阻方面取得重大突破,自然层流机翼技术成为研究热点.总结了层流技术类别,回顾了自然层流机翼的主要研究历程,介绍了当前正在开展的欧洲TELFONA计划和美国ERA计划中的自然层流机翼的研究进展,概述了自然层流机翼应用情况和自然层流短舱,分析了自然层流机翼的实际应用难题,展望了自然层流技术在新一代民用飞机中的应用.     

Interlaced optimal-REQUEST and unscented Kalman filtering for attitude determination

 Aimed at low accuracy of attitude determination because of using low-cost components which may result in non-linearity in integrated attitude determination systems, a novel attitude determination algorithm using vector observations and gyro measurements is presented. The various features of the unscented Kalman filter (UKF) and optimal-REQUEST (quaternion estimator) algorithms are introduced for attitude determination. An interlaced filtering method is presented for the attitude determination of nano-spacecraft by setting the quaternion as the attitude representation, using the UKF and optimal-REQUEST to estimate the gyro drifts and the quaternion, respectively. The optimal-REQUEST and UKF are not isolated from each other. When the optimal-REQUEST algorithm estimates the attitude quaternion, the gyro drifts are estimated by the UKF algorithm synchronously by using the estimated attitude quaternion. Furthermore, the speed of attitude determination is improved by setting the state dimension to three. Experimental results show that the presented method has higher performance in attitude determination compared to the UKF algorithm and the traditional interlaced filtering method and can estimate the gyro drifts quickly.     

钛合金表面等离子喷涂ZrO2-NiCoCrAIY梯度涂层的抗热震行为

ZrO2-梯度涂层的成分沿厚度方向呈连续梯度化分布,提高了涂层与基体的粘结强度和涂层的内聚强度,其抗热震性能优于双层涂层.在较大热冲击应力作用下,梯度涂层整体自基体表面剥落而失效;在较小热冲击应力作用下,由于NiCoCrAIY底层与TC4合金基体发生了热相互作用,改善了涂层与基体的结合状况,梯度涂层纵向断裂并部分自基体表面剥落而失效.     

西安卫星测控中心的软件过程改进实践

为了提高航天测控软件的开发效率,保证软件产品质量,西安卫星测控中心启动了基于GJB 5000-2003 2级等级的软件过程改进工作,并于2008年通过了军用软件研制能力2级正式评价。本文介绍了西安卫星测控中心的软件过程改进实践,阐述了软件过程改进实践中取得的经验体会。     

Dispersion-free quantum clock synchronization via fiber link

We proposed a fiber-based quantum clock synchronization protocol by employing the dispersion cancellation feature of the frequency anti-correlated entangled source under the quantum interference measurement. It is shown that, the accuracy of the synchronization is mainly dependent on the bandwidth of the frequency entangled biphoton spectrum and on the temperature variation induced fluctuations in both the reference fiber coiling and the fiber link. With this proposal, synchronization between two clocks at a distance of ten kilometers can be implemented with an accuracy below a picosecond.     

支线货运无人机的发展现状、运行方式与关键技术分析

支线货运无人机为偏远地区、山地、高原、海岛和城市快捷货运等提供了一种更经济、更高效的物资运输方式,并在应急救援和前线补给中发挥着重要作用。本文回顾了支线货运无人机的国内外发展现状,对比了支线货运无人机与有人机、陆地交通之间的竞争优势,论述了当前技术条件下支线货运无人机相对安全的运行方式——点对点管道飞行,并分析了支线货...     

红外头罩电弧风洞试验状态的量化新判据

提出了一种红外空空弹红外头罩电弧风洞试验状态的量化新判据.研究表明:热应力是导弹高速飞行时头罩应力的最大影响因素,可用最大热应力作为电弧风洞试验状态的确定判据取代目前国内现有试验状态确定判据.通过准确的气动热应力计算,可保证红外头罩的电孤风洞试验状态与飞行环境的一致.     

卫星遥感图像分块小波变换编码方案

提出一种分块小波变换（ＢｌｏｃｋｉｎｇＷａｖｅｌｅｔｓＴｒａｎｓｆｏｒｍ）方案。该数据压缩方案可节省存储时间，为星上应用提供了可能性。利用各基带之间的自相似性，对小波系数采用改进型零树编码（ＩｍｐｒｏｖｅｄＺｅｒｏｔｒｅｅＥｎｃｏｄｉｎｇ），可有效的提高压缩比。