A Survey of Underwater Multi-Robot Systems

As a cross-cutting field between ocean development and multi-robot system (MRS), the underwater multi-robot system (UMRS) has gained increasing attention from researchers and engineers in recent decades. In this paper, we present a comprehensive survey of cooperation issues, one of the key components of UMRS, from the perspective of the emergence of new functions. More specifically, we categorize the cooperation in terms of task-space, motion-space, measurement-space, as well as their combination. Further, we analyze the architecture of UMRS from three aspects, i.e., the performance of the individual underwater robot, the new functions of underwater robots, and the technical approaches of MRS. To conclude, we have discussed related promising directions for future research. This survey provides valuable insight into the reasonable utilization of UMRS to attain diverse underwater tasks in complex ocean application scenarios.      

故障装备检测任务分解模型评估

为解决故障装备检测过程存在的突出问题,提高检测任务的执行效率,降低任务执行过程中的复杂程度,在掌握一般检测任务执行过程的基础上,总结了现有故障装备检测过程中常见任务的不同类型;以检测过程中相互间具有约束关系的任务分解为研究对象,借鉴任务关联矩阵(TAM)等相关概念,提出了基于检测任务分解的评估方法和过程模型,从检测周期和资源占用2个角度实现了对检测任务分解程度的定性分析,对任务内聚性、耦合性以及均衡性的定量计算,最后通过实例验证了该方法和模型的可行性,为评估不同检测任务分解方案提供了参考。     

LabWindows/CVI多线程技术的应用

LabWindows/CVI多线程技术可保证并发任务的顺利执行。多线程技术解决了并发任务之间的冲突问题,能大幅提高工作效率。针对多个线程之间数据共享与传递,提供了良好的数据保护机制。文中对数据保护的机制与具体实现方法进行了阐述,结合多线程技术完成了仪器自动控制界面开发,试验证明,多线程技术的优势在并发任务系统中得到良好的体现。     

异构分布式系统中一种新型主副版本调度算法

针对异构分布式系统中处理器数量相对较少时优先级约束条件带来的副版本调度易失败问题，提出一种新型高可靠性主副版本调度算法（HRPB）。任务模型以有向无环图（DAG）表示，该算法共计调度主、副两个版本的任务。在任务优先级排序阶段，根据任务执行时间及截止时限来制定新指标平均最晚开始时间（ALST）进行排序；在任务处理器分配阶段，采取多一重备份策略以解决处理器数量相对较少时优先级约束条件带来的副版本调度易失败问题，并且改进了副版本调度时的可靠性指标计算方法。通过随机生成DAG图进行算法仿真测试，实验结果表明，HRPB比eFRD具有更优的副版本调度成功率、更高的系统可靠性。     

Chosen postures during specific sitting activities

This research study analysed the interaction between people's postures and activities while in semi-public/leisure situations and during transportation (journey by train). In addition, the use of small electronic devices received particular emphasis. Video recordings in German trains and photographs in Dutch semi-public spaces were analysed using a variation of Branton and Grayson's (An evaluation of train seats by observation of sitting behaviour. Ergonomics, 10 (1), (1967), 35–51) postural targeting forms and photos. The analysis suggests a significant relationship between most activities and the position of the head, trunk and arms during transportation situations. The relationship during public situations is less straightforward. Watching, talking/discussing and reading were the most observed activities for the transportation and leisure situations combined. Surprisingly, differences in head, trunk, arm and leg postures were not significant when using small electronic devices. Important issues not considered in this study include the duration of the activities, the gender and age of observed subjects and the influence of the time of day. These are interesting issues to consider and include for future research.

Statement of Relevance: This study shows what activities people choose to carry out and their related postures when not forced to a specific task (e.g. driving). The results of this study can be used for designing comfortable seating in the transportation industry (car passenger, train, bus and aircraft seats) and semi-public/leisure spaces.     

谈业主方在项目各阶段的重点管理任务——装载机项目管理工作简析

随着国内工程机械行业的发展,工程机械厂房建设规模越来越大,论文结合装载机项目管理的实际情况,简要分析了业主方在项目管理各阶段的重点管理任务,并对项目管理实施过程中部分管理做法的优劣做简要分析。     

Workforce planning and deployment for a hospital reservation call center with abandonment cost and multiple tasks

We consider a hospital reservation call center where operators handle multiple tasks. We take into account operator labor costs, caller waiting costs, and abandonment costs for lost calls. Instead of relying on the traditional method of queueing theory for call center management, we present a method that obtains expected caller waiting time and expected abandonment rate directly by introducing the inbound-load parameter. We develop a framework that combines workforce planning and operator deployment for a mixed call center in a single mathematical programming model. This paper also demonstrates how the proposed methodology can be applied in practice, with a case study based on actual operational data. Our primary conclusion is that the method presented in this research can significantly reduce both expected total cost (by 55.1% in our case study) and abandonment rate (from 15% to 2.1% in our case study). In addition, we demonstrate, using a sensitivity analysis, that our methodology will be more effective in an environment where the unit penalty cost of an abandoned call is relatively high among competitive hospitals.     

Effects of psychosocial and individual factors on physiological risk factors for upper extremity musculoskeletal disorders while typing

Psychosocial factors are hypothesized to contribute to work-related musculoskeletal disorder (WMSD) development, although previous research has been largely epidemiological or has focused primarily on the shoulders, back and neck. The objective of this study was to quantify the effects of mental workload and time pressure on perceived workload and physiological responses of the distal upper extremity. A total of 18 typists completed nine 5-min typing sessions representing three levels of time pressure and mental workload. Levels were manipulated by adjusting typing speed and by requiring participants to perform arithmetic tasks while typing. Outcomes were measured in muscle activation levels, wrist postures and movements, key strike force and subjective assessments of workload. In general, increased time pressure increased muscle activation, key strike force and wrist deviations; and increased mental workload increased key strike force. Mental workload and time pressure mediated physical risk factors during typing to increase WMSD risk for the distal upper extremity.     

Classification of brain hemodynamic signals arising from visual action observation tasks for brain–computer interfaces: A functional near-infrared spectroscopy study

A brain–computer interface (BCI) is a way of translating an individuals’ thoughts to control a computer or an external mechanical device. Studying brain activities in a reproducible manner, this study explores the possibility of using real-time functional-near infrared spectroscopy (fNIRS) to detect brain hemodynamic features for BCI commands. Sixteen channel brain activities associated with two distinct mental tasks were measured from seven healthy subjects. The tasks represented neural activities arising from a visual observation of a motor action related to hand movements of the subjects. Sensitive signatures of task relevant neural activities were further extracted from hemodynamic signals in the prefrontal cortex of the brain, and subsequently were translated into pre-determined computer commands using a set of algorithms. The decoded commands allowed volunteer subjects to control an external device in real-time through their mental intentions. The obtained results demonstrate the potential of the current study as an alternative fNIRS-BCI paradigm.     

从"5.12"地震看应急性非战争军事行动装备保障建设

应急性非战争军事行动装备保障的主要特点有：准备时间短，要求实施联合装备保障；任务多样化，保障内容具有复杂性；专业性强，被保障对象具有针对性。根据应急性非战争军事行动装备保障建设应贯彻的指导思想与基本原则，分析其基本对策，包括：加强非战争军事行动装备保障演练、健全军民一体社会化装备保障机制、加强特种装备的开发与研制等。