Leader-following coordination of multi-agent systems with information feedback

Based on the strategy of information feedback from followers to the leader, flocking control of a group of agents with a leader is studied. The leader tracks a pre-defined trajectory and at the same time the leader uses the feedback information from followers to the leader to modify its motion. The advantage of this control scheme is that it reduces the tracking errors and improves the robustness of the team cohesion to followers＇ faults. The results of simulation are provided to illustrate that information feedback can improve the performance of the system.

On String Stable Control of Platoon of Automated Vehicles with Predecessor-successor Information Framework

For the constant distance spacing policy,the existing researches of the string stability focus on the single-predecessor information framework（SPIF） and predecessor-successor information framework（PSIF）.The research results demonstrated that the string stability could not be guaranteed with the SPIF,and then the PSIF was proposed to resolve this string instability.But the issue,whether the string stability can be guaranteed when applying the PSIF,is still controversial.Meanwhile,most of the previous researches on the string stability were conducted without consideration of the parasitic time delays and lags.In this paper,the practical longitudinal vehicle dynamics model is built with consideration of the parasitic time delays and lags existing in the actuators,sensors or the communication systems.Secondly,the detailed theoretical analysis of string stability in frequency domain is conducted to demonstrate that the classical linear control laws can not ensure the string stability when applying both the symmetrical PSIF（SPSIF） and asymmetrical PSIF（APSIF）.Thirdly,a control law,which adds the position and velocity information of the leading vehicle,is proposed to guarantee string stability for small/medium platoon,and the other control law,which adds the acceleration information of the controlled vehicle,is proposed to guarantee string stability for large platoon as well as small/medium platoon.Finally,the comparative simulation is conducted to confirm the conducted analysis and the proposed control laws.The conducted research completes the means to analyze the string stability in frequency domain,provides the parameters＇ reference for the design and implementation of the practical automatic following controllers,and improves the reliability and stability of the platoon of automatic vehicles.

缺乏位置信息的视觉移动机器人leader-following编队控制

针对视觉移动机器人编队在缺乏位置信息情况下的控制问题,提出一种基于视觉的leader-following编队反馈控制方法。该方法利用leader标志物特征点在follower摄像机像平面上的坐标信息设计了观测器,对leader与follower间的相对位置进行估计,基于相对位置估计量与它们速度的关系,设计出leader-following编队反馈控制器,通过Lyapunov理论证明了闭环系统的稳定性。仿真结果表明,该控制方法能有效解决缺乏位置信息情况下视觉移动机器人编队的控制问题。

Effects of information transmission delay and channel blocking on synchronization in scale-free Hodgkin-Huxley neuronal networks

In this paper,we investigate the evolution of spatiotemporal patterns and synchronization transitions in dependence on the information transmission delay and ion channel blocking in scale-free neuronal networks.As the underlying model of neuronal dynamics,we use the Hodgkin-Huxley equations incorporating channel blocking and intrinsic noise.It is shown that delays play a significant yet subtle role in shaping the dynamics of neuronal networks.In particular,regions of irregular and regular propagating excitatory fronts related to the synchronization transitions appear intermittently as the delay increases.Moreover,the fraction of working sodium and potassium ion channels can also have a significant impact on the spatiotemporal dynamics of neuronal networks.As the fraction of blocked sodium channels increases,the frequency of excitatory events decreases,which in turn manifests as an increase in the neuronal synchrony that,however,is dysfunctional due to the virtual absence of large-amplitude excitations.Expectedly,we also show that larger coupling strengths improve synchronization irrespective of the information transmission delay and channel blocking.The presented results are also robust against the variation of the network size,thus providing insights that could facilitate understanding of the joint impact of ion channel blocking and information transmission delay on the spatiotemporal dynamics of neuronal networks.

Verifying the Effects of an Education Program Leveraging Information Technology to Promote Cervical Cancer Screening in Women Aged 20 - 29—A One-Year Longitudinal Study

The purpose of this research is to implement an IT-based education program in order to promote cervical cancer screenings for women aged 20 - 29 years, as well as to examine the results of said program. This is a longitudinal/comparative study of two groups, one for which the program was implemented (the intervention group), and the other for which it was not (the control group). The program consisted of attending a health lecture and encouragement to be screened one month, six months, and one year later sent through IT-based methods. The target was unmarried women aged 20 - 29 who had neither previously given birth nor had been screened for cervical cancer in a period one year prior. They were divided into two groups, the intervention group (n = 142) and control group (n = 145). The effectiveness of the program was assessed via an initial survey and further surveys six months and one year later. Results were based on the Japanese version of the Health Belief Model Scale for Cervical Cancer and the Pap Smear Test (HBMSCCPST), knowledge scores in the categories of Healthy Lifestyles, Cervical Cancer, Cervical Cancer Screening, and screening behavior. A two-way ANOVA of the HBMSCCPST subscales and knowledge scores in the initial, six-month, and one-year surveys was performed, showing interaction in Cervical Cancer (p = 0.00). Main effects were observed in Cervical Cancer Screening (p = 0.00) and Healthy Lifestyles (p = 0.00). Regarding the amount of change from the initial survey, knowledge scores in the Cervical Cancer (p = 0.027) and Cervical Cancer Screening (p = 0.016) categories were significantly higher in the intervention group than in the control group. There was no significant difference in cervical cancer screening rates (p = 0.26) between the two groups. However, a small-degree effect size was observed for Benefits, Seriousness, and Susceptibility subscales in both examinees and non-examinees. Although the educational program of this study was effective in improving the knowledge of women in their twenties, there was little improvement in HBMSCCPST and it did not lead to the promotion of cervical cancer screening. In order to raise interest in cervical cancer screening, it is necessary to consider useful content to guide women to consult with healthcare professionals, a long-term population approach, and organizational structure of consultation.

The Second International Workshop on Geographical Information System Held in Beijing,August 9-11,1990

TheThe Second International Workshop on Geographical Information System(2nd IWGIS Beijing’90)was held recently in Beijing under the auspices of the Laboratory of Resources and Environment Information System(LREIS)and cosponsorship of the Chinese Academy of Sciences,National Natural Science Foundation of China,National Remote Sensing Centre of China,Geographical Society of China,and International Development Research Centre of Canada(IDRC).

Efficiency promotion for an on-ramp system based on intelligent transportation system information

Effect of cars with intelligent transportation systems （ITSs） on traffic flow near an on-ramp is investigated by car-following simulations. By numerical simulations, the dependences of flux on the inflow rate are investigated for various proportions of cars with ITSs. The phase diagrams as well as the spatiotemporal diagrams are presented to show different traffic flow states on the main road and the on-ramp. The results show that the saturated flux on the main road increases and the free flow region is enlarged with the increase of the proportion of cars with ITS. Interestingly, the congested regions of the main road disappear completely when the proportion is larger than a critical value. Further investigation shows that the capacity of on-ramp system can be promoted by 13% by using the ITS information, and the saturated flux on the on-ramp can be kept at an appropriate value by adjusting the proportion of cars with ITS.

Developing architecture of a traveler information system for dynamic equilibrium in traffic networks

Having criticized the current architecture of Advanced Traveler Information Systems （ATISs）, this work discusses a new base of requirements to develop a new paradigm for traffic information systems. It mainly integrates three dimensions within a traffic system： drivers＇ pattern of behavior and preferences, urban traffic desires, and capabilities of traffic information service providers. Based on the above, functional segments from several related backgrounds are brought together to structure a new architecture, called Interactive Traveler Information System （ITIS）. The main interactive feature of this new architecture is a two-way communication track between drivers and the traffic information system provider-in fact, a decision on choosing a road at a particular time for an individual will be made based on the utility of both sides. This new configuration consists of driver-side smartphone application, centric traffic prediction, and decision-maker units, which will shape a new approach of decision-making processes. These all work together to satisfy the designated goal of ITIS, which is preserving the Wardrop equilibrium condition in the traffic network level. Finally, we concentrate on a comparison study, which shows a differentiation between performance of the proposed ITIS and the current ATIS model in a real situation. This has been done with simulations of analogical scenarios. The most noticeable advantage of the proposed architecture is not being limited to a saturation limit, and the positive effect of increasing system penetration in the performance of the newly introduced information system. In conclusion, new research subjects are suggested to be carried out.

Towards delivery of situational information in distributed environments

In the distributed environment,robots should be able to provide users with adaptive services automatically according to the situational information changing dynamically which is obtained from both users and their environments.The workflow depends on situational information obtained from physical environments and provides context-aware services automatically based on the information retrieved.And the workflow in the business processes and the distributed computing environments have supported the automation of services by connecting tasks.The workflow needs to specify ubiquitous situational information as state-transition constraints.However,the delivery and use of sensor data in the workflow is a difficult problem for the robot system.In order to bridge the gap between applications and low-level constructs and to acquire raw situational information for the execution of the context-aware workflow in the robot systems,this paper presents an approach which can achieve the sensor data transmission between a sensing server and a robot system easily.

带落角约束的新型领弹-从弹固定时间协同制导律

针对多导弹以期望角度协同攻击机动目标问题,提出了一种新型领弹-从弹固定时间协同制导律。根据弹目相对运动关系建立了领弹-从弹协同制导模型;基于固定时间滑模控制理论设计了视线法向上的制导律,实现了领弹和从弹以期望的攻击角度对机动目标进行精准打击。在从弹视线方向上,基于一致性误差函数和固定时间滑模趋近律,设计了一种从弹视线方向制导律,充分利用了导弹间的信息交互,实现了从弹与领弹的剩余时间在固定时间内快速趋于一致。数值仿真和对比试验结果表明:所提制导律对时间协同和角度约束的控制精度高,避免了奇异和抖振现象,收敛速度快且收敛时间上界与初始状态无关,充分地验证了所提制导律的有效性和优越性。

AIC与BIC在亲体-补充量模型选择中的应用及比较

由于渔业资源评估中补充量的剧烈变动、亲体量的测量误差以及时间序列的偏差常常使亲体 补充量(SR)关系模型的确定存在很大偏差问题。本文以7种SR(Stock Recruitment)模型的模拟数据作为观测数据,研究了AIC(AkaikeInfor mationCriterion)与BIC(BayesianInformationCriterion)在SR模型选择中的应用。作为例证,文中采用AIC和BIC对8组实际的SR数据进行了SR模型的选择,并对其结果进行了比较。参数的估计方法为最大似然法(Maximumlikelihoodmethod)。结果表明,AIC和BIC在SR模型选择中是有效的。但是,对于嵌套模型,BIC可能比AIC更有效。

信息-动机-行为技巧模型在创伤下肢截肢病人延续性护理中的应用

[目的]建立以信息-动机-行为技巧模型(IMB)为基础的创伤下肢截肢病人随访管理模式,改善截肢术后病人的生存状态。[方法]将62例因创伤导致的下肢截肢病人随机分为观察组和对照组各31例,对照组采用常规出院管理模式,观察组采用以IMB为基础的出院病人管理模式。比较两组病人进行康复锻炼的依从性、干预前后健康状况调查问卷(SF-36)得分及跌倒效能量表(mFES)得分。[结果]观察组病人进行康复锻炼依从性明显高于对照组(P<0.01)。干预后观察组病人的SF-36总分、躯体健康相关生活质量、心理健康相关生活质量及mFES总分、室内跌倒效能评分、室外跌倒效能评分均明显高于对照组(P<0.05)。[结论]基于IMB模型提供的信息、动机和行为干预,能够明显提升下肢截肢病人进行康复锻炼的依从性,改善病人的生存质量,促进病人康复。

2015-2016年河北省沧州市疑似预防接种异常反应监测

目的分析2015-2016年河北省沧州市疑似预防接种异常反应(AEFI)的发生特征,评价AEFI信息管理系统运转情况。方法通过全国AEFI信息管理系统收集2015年1月1日-2016年12月31日报告的AEFI个案数据,采用描述性流行病学方法对相关指标进行流行病学分析。结果 2015-2016年沧州市共报告AEFI病例3 701例,报告发生率为49.54/10万,以<2岁、2~7岁年龄段为主,分别占78.47%和21.24%。一般反应3 675例,占报告病例的99.30%,以发热、红肿、硬结为主;异常反应23例,占报告病例的0.62%。AEFI个案发生在接种后当天或第2天,占报告病例的96.65%,治愈和好转占99.32%。AEFI县乡覆盖率均为100%,及时报告率为99.78%,个案表完整调查率、AEFI及时调查率和AEFI分类率均为100%。结论沧州市AEFI信息管理系统运转正常,监测指标和监测敏感性较高。

基于Zooming-Panning模式的可视化信息浏览技术的研究

对目前已有的多种浏览技术作了深入细致的研究和分析。针对Zooming-Panning技术在具体的技术实现上不够全面,既不能保证可视化表示的结构具有一致性,也不能使可视化表示具有良好的显示效果这一情况,依据几何光学的有关原理,实现了一个能够对可视化表示动态跟踪调节的跟随因子,用于补充该技术在实现上的不足,并同时把该技术提出的两个标准扩充为三个,形成的结果称为基于自约束路径的Zooming-Panning浏览技术。实践证明,基于自约束路径的Zooming-Panning技术具有良好的浏览效果。

Event-triggered Tracking Consensus with Packet Losses and Time-varying Delays

This paper mainly investigates the event-triggered tracking control for leader-follower multi-agent systems with the problems of packet losses and time-varying delays when both the first-order and the second-order neighbors' information are used. Event-triggered control laws are adopted to reduce the frequency of individual actuation updating under the sampleddata framework for discrete-time agent dynamics. The communication graph is undirected and the loss of data across each communication link occurs at certain probability, which is governed by a Bernoulli process. One numerical example is given to demonstrate the effectiveness of the proposed methods. It is found that the tracking consensus is sped up by using the second-order neighbors' information when packet losses and time-varying delays occur. © 2014 Chinese Association of Automation.

非处罚性监管改善了上市公司信息环境吗?--基于分析师行为视角的考察

本文以2015-2019年沪深A股非金融类上市公司数据为样本,考察交易所问询函监管对分析师行为的影响。研究发现,被交易所问询函监管的公司,分析师跟踪数目更多,分析师盈余预测乐观度更低、准确度更高、分歧度更小;交易所问询函包含的问题数越多,需要中介机构或独立董事发表专业核查意见,涉及内部控制、收入等明确内容以及关联交易或并购等重大事项时,分析师跟踪数目更多,盈余预测乐观度更低、准确度更高、分歧度更小;分析师声誉越高、行业专长越高,对被问询的上市公司的盈余预测准确度越高、分歧度越小;交易所问询函监管会使分析师预测修正频率增加,有利于提高盈余预测准确度、降低分歧度,还能通过分析师渠道发挥一定的溢出效应,促进分析师整体盈余预测乐观度的降低、准确度的提升。所以,交易所问询函监管能够通过分析师渠道发挥外部治理效应,对改善我国上市公司信息环境具有重要意义。