在轨跟踪与数据中继卫星测控关键技术(上)

根据卫星轨道根数，研究了跟踪与数据中继卫星（TDRS）对用户星的精确跟踪规律，并据此分析了TDRS对卫星平台姿态和天线运动范围的要求。介绍了TDRS测控中的关键技术，如螺旋扫描算法在TDRS搜索用户星时的应用、TDRS对近地卫星的覆盖率、TDRS跟踪多用户星的资源分配准则、星蚀和日凌计算，以及轨道位置保持控制策略等。相关控制策略的正确性已在我国地球同步轨道卫星的在轨测控应用中得到了证实，可用于未来TDRS的工程测控和业务应用。     

柔索牵引式力觉交互机器人工作空间分析

为了在地面上实现航天员的虚拟作业训练,基于柔索牵引式并联机器人,研究了与VR技术结合的柔索牵引式力觉交互机器人的力螺旋可行工作空间。建立平面柔索的静力学模型,分析竖直平面内4柔索3自由度末端执行器不同位姿及人机交互力下的力螺旋可行工作空间,对比分析了柔索牵引式力觉交互机器人在实际应用中交叉柔索不同布局方式、外力旋量和末端执行器不同结构参数对力螺旋可行工作空间的影响。确定了合理的柔索牵引式力觉交互机器人的力螺旋可行工作空间、合理的柔索布局、末端执行器的结构参数。因为柔索牵引式力觉交互机器人具有工作空间大、可以提供较大的力及力矩、刚度可变、安全性高、人机交互性强等优点,因此可以满足航天员虚拟作业训练的需求。     

Effect of salt stress on growth and physiology in amaranth and lettuce: Implications for bioregenerative life support system

Growing plants can be used to clean waste water in bioregenerative life support system (BLSS). However, NaCl contained in the human urine always restricts plant growth and further reduces the degree of mass cycle closure of the system (i.e. salt stress). This work determined the effect of NaCl stress on physiological characteristics of plants for the life support system. Amaranth (Amaranthus tricolor L. var. Huahong) and leaf lettuce (Lactuca sativa L. var. Luoma) were cultivated at nutrient solutions with different NaCl contents (0, 1000, 5000 and 10,000 ppm, respectively) for 10 to 18 days after planted in the Controlled Ecological Life Support System Experimental Facility in China. Results showed that the two plants have different responses to the salt stress. The amaranth showed higher salt-tolerance with NaCl stress. If NaCl content in the solution is below 5000 ppm, the salt stress effect is insignificant on above-ground biomass output, leaf photosynthesis rate, Fv/Fm, photosynthesis pigment contents, activities of antioxidant enzymes, and inducing lipid peroxidation. On the other hand, the lettuce is sensitive to NaCl which significantly decreases those indices of growth and physiology. Notably, the lettuce remains high productivity of edible biomass in low NaCl stress, although its salt-tolerant limitation is lower than amaranth. Therefore, we recommended that amaranth could be cultivated under a higher NaCl stress condition (<5000 ppm) for NaCl recycle while lettuce should be under a lower NaCl stress (<1000 ppm) for water cleaning in future BLSS.     

SpaceMocap：在轨人体运动捕捉系统

SpaceMocap是一套基于多RGB-D相机的计算机视觉航天员运动捕捉系统。地面准备阶段，扫描航天员模型，并分别标定彩色相机的内参数。在轨采集阶段，3~4台相机布置在舱内角落，同步采集航天员任务视频。地面处理阶段，通过相机外参数标定和ICP方法实现点云融合，采用深度神经网络对人体关节点位置进行检测并初始化位姿参数，再用改进的ICP方法进行位姿求精，实现序列图像中关节角度跟踪。本系统搭载TG-2升空，对SZ-11航天员的任务视频进行了采集和处理，首次获取了在轨航天员的姿态(包括中性体位)、占位空间、运动参数等重要数据。结果表明，运动捕捉的模型与点云具有良好的重合度，关节点位置与关节角度具有较高的跟踪精度。SpaceMocap是我国首个在轨运动捕捉系统，它小型、轻质，具有计算机视觉特有的非接触测量、直观、高精度优势，无需在人体上粘贴任何标志，具有良好的抗遮挡能力，完全适用于微重力、狭小空间环境下的在轨应用 。     

Software defect prevention based on human error theories

Software defect prevention is an important way to reduce the defect introduction rate.As the primary cause of software defects,human error can be the key to understanding and preventing software defects.This paper proposes a defect prevention approach based on human error mechanisms:DPeHE.The approach includes both knowledge and regulation training in human error prevention.Knowledge training provides programmers with explicit knowledge on why programmers commit errors,what kinds of errors tend to be committed under different circumstances,and how these errors can be prevented.Regulation training further helps programmers to promote the awareness and ability to prevent human errors through practice.The practice is facilitated by a problem solving checklist and a root cause identification checklist.This paper provides a systematic framework that integrates knowledge across disciplines,e.g.,cognitive science,software psychology and software engineering to defend against human errors in software development.Furthermore,we applied this approach in an international company at CMM Level 5 and a software development institution at CMM Level 1 in the Chinese Aviation Industry.The application cases show that the approach is feasible and effective in promoting developers' ability to prevent software defects,inde pendent of process maturity levels.     

Initial design of laboratories for sustainable habitation

An effective and self-sustainable artificial habitat design is essential for human spaceflight and expansion of mankind into orbit or towards other celestial bodies. There are two approaches that need to be implemented in future sustainable habitats: the use of re-cycling technologies in order to gain experience in closed-loop processes and the primary production of resource materials using In Situ Resource Utilisation (ISRU) principles. Various products will be provided and, where applicable, recycled in such a system taking into account basic human factors requirements such as crew work load capacity, safety and well-being, namely:     

浅谈中小企业如何引进和留住人才

作为资本有限的中小企业,不可能拿出大笔资金用于培训和招揽人才,但作为中小企业的经营者,在头脑中必须要有人才第一的观念,想尽一切办法去引进人才,留住人才,只有这样才能更好地适应新环境,促进新发展.     

密闭容器试验用人体代谢模拟装置

文章简要介绍了人体代谢地面模拟装置的原理、结构组成和应用结果。为在密闭容器中进行地面模拟试验,考核产品性能提供了一个较为可靠而全面的模拟环境。     

政府采购合同法律性质探析

政府采购合同以民事合同为表现形式,反映了平等主体间的财产关系,具有私法性质。它的本质是通过合同实现政府意志和社会公共利益,有不同于民事合同的实质性特点。政府采购合同是政府进行宏观调控,更好发挥财政手段配置社会资源的效用,实现效益与社会公平的必要途径。     

Application of reliability technologies in civil aviation: Lessons learnt and perspectives

We consider reliability engineering in modern civil aviation industry, and the related engineering activities and methods. We consider reliability in a broad sense, referring to other system characteristics that are related to it, like availability, maintainability, safety and durability. We covered the entire lifecycle of the equipment, including reliability requirement identification, reliability analysis and design, verification and validation of reliability requirements (typically involved in the equipment design and development phase), quality assurance (which typically enters in the manufacturing phase), and fault diagnosis and prognosis and maintenance (which are connected to the operation phase). Lessons learnt from reliability engineering practices in civil aviation industry are given, which might serve as reference for reliability managers and engineers, also from other industries with high reliability requirements.