Guaranteed Cost Attitude Tracking Control for Uncertain Quadrotor Unmanned Aerial Vehicle Under Safety Constraints

In this paper,guaranteed cost attitude tracking con-trol for uncertain quadrotor unmanned aerial vehicle(QUAV)under safety constraints is studied.First,an augmented system is constructed by the tracking error system and reference system.This transformation aims to convert the tracking control prob-lem into a stabilization control problem.Then,control barrier function and disturbance attenuation function are designed to characterize the violations of safety constraints and tolerance of uncertain disturbances,and they are incorporated into the reward function as penalty items.Based on the modified reward function,the problem is simplified as the optimal regulation problem of the nominal augmented system,and a new Hamilton-Jacobi-Bellman equation is developed.Finally,critic-only rein-forcement learning algorithm with a concurrent learning tech-nique is employed to solve the Hamilton-Jacobi-Bellman equa-tion and obtain the optimal controller.The proposed algorithm can not only ensure the reward function within an upper bound in the presence of uncertain disturbances,but also enforce safety constraints.The performance of the algorithm is evaluated by the numerical simulation.

UAVs cooperative task assignment and trajectory optimization with safety and time constraints

This paper proposes new methods and strategies for Multi-UAVs cooperative attacks with safety and time constraints in a complex environment.Delaunay triangle is designed to construct a map of the complex flight environment for aerial vehicles.Delaunay-Map,Safe Flight Corridor(SFC),and Relative Safe Flight Corridor(RSFC)are applied to ensure each UAV flight trajectory's safety.By using such techniques,it is possible to avoid the collision with obstacles and collision between UAVs.Bezier-curve is further developed to ensure that multi-UAVs can simultaneously reach the target at the specified time,and the trajectory is within the flight corridor.The trajectory tracking controller is also designed based on model predictive control to track the planned trajectory accurately.The simulation and experiment results are presented to verifying developed strategies of Multi-UAV cooperative attacks.

Healthcare Staff Perceptions of Patient Safety Culture in Nursing Home Settings—A Cross-Sectional Study

In nursing homes, knowledge about patient safety culture is still limited. This study investigates staff perceptions of patient safety culture in Norwegian nursing homes, measured with the Nursing Home Survey on Patient Safety Culture (NHSOPSC). 466 (69%) staff from 12 different nursing homes participated. The total percentages of positive responses for each patient safety culture dimension and differences in perceptions according to staff’s educational background and position were calculated. Multiple linear regression analysis was used to test if the NHSOPSC dimensions predicted participants’ ratings of the question “Please give this nursing home an overall rating on patient safety”. The proportion of positive responses was high, with six of ten dimensions having an average percentage above 70%. “Supervisor expectations and actions promoting patient safety” (88%), “feedback and communication about incidents” (87%), and a “non-punitive response to mistakes” (78%) had high average scores, while “staffing” (46%) and “training and skills” (56%) had the lowest average scores. Managers reported higher scores on all dimensions, except for “compliance with procedures” compared with other staff groups. Educational level had less influence on staff’s perceptions of patient safety culture than management position. The ten NHSOPSC dimensions explained 47.2% of the variance for the overall rating question “Please give this nursing home an overall rating on patient safety” (F [10, 384] = 34.39, p < 0.001). “Management and organizational learning” had the strongest unique contribution (28.1%). This study suggests that staff working at the bedside have confidence in their nursing managers’ attention to patient safety issues and that a non-punitive environment is prevalent in Norwegian nursing homes.

Attitudes and actions of hospitalized patients on management of their safety：a cross-sectional study

Background and aims： Patient plays an important role in preventing the adverse events （AEs） and harms occurredduring medical care; however, the incidence of AEs and harms can be effectively reduced if patients actively andsuccessfully participate in their care. Organizations of safety management for patients and authorities of health systemagree that involve patients into the management on their care can obviously prevent medical error; whereas, the attitudesand actual actions of hospitalized patients for the view remain controversial. In this study, we aimed to explored patients’attitudes and actual actions participate in their own safety and whether patients with positive attitude are more likely totake action than others？ Methods： In the present cross-sectional study, convenience sampling method was adopted torecruit a sample size consist of 2052 patients from two teaching hospitals affiliated to Medical College of ShantouUniversity located in Shantou China. We used a questionnaire consist of 7 items to investigate the attitudes and actualactions of hospitalized patients participating in their care. Then the actual actions between patients with positive andnegative attitudes were analyzed using descriptive analysis and independent t-test. Results： Most patients have a positiveattitude on engaging in their safety management activity. Although most patients have positive attitude, fewer can takeactual actions. Patients with positive attitude are more likely to take actions, but there are not statistical significantdifference for positive and negative attitudes patients in terms of some items, such as “Ask doctor or nurse to wash theirhands” and “Ask nurse or doctor to confirm your identity”, etc. Conclusions： Positive attitude is an important factor thatimproves the rate of participating in the medical care activity for patients. Based on the results of current study,interventions that improve the attitude of patient are needed to improve patients’ attitude and what is more important ishow to convert attitude into actual action. When making plan of interventions, cultural background of patients need to betaken into account.

Assessment of knowledge,cultural beliefs,and behavior regarding medication safety among residents in Harbin,China

BACKGROUND Medication misuse or overuse is significantly associated with poor health outcomes.Information regarding the knowledge,cultural beliefs,and behavior about medication safety in the general population is important.AIM To conduct a survey on medication habits and explored the potential factors impacting medication safety.METHODS The current survey included adults from 18 districts and counties in Harbin,China.A questionnaire on medication safety was designed based on knowledge,cultural beliefs,and behavior.Both univariate and multivariate analyses were used to explore the factors that impacted medication safety.RESULTS A total of 394 respondents completed the questionnaires on medication safety.The mean scores for knowledge,cultural beliefs,and behavior about medication safety were 59.41±19.33,40.66±9.24,and 60.97±13.69,respectively.The medication knowledge score was affected by age(P=0.044),education(P<0.001),and working status(P=0.015).Moreover,the cultural beliefs score was significantly affected by education(P<0.001).Finally,education(P=0.003)and working status(P=0.011)significantly affected the behavior score.CONCLUSION The knowledge,cultural beliefs,and behavior about medication safety among the general population was moderate.Health education should be provisioned for the elderly,individuals with a low education level,and the unemployed to improve medication safety in Harbin,China.

Stability evaluation method of large cross-section tunnel considering modification of thickness-span ratio in mechanized operation

Purpose-This study aims to research the large cross-section tunnel stability evaluation method corrected after considering the thickness-span ratio.Design/methodology/approach-First,taking the Liuyuan Tunnel of Huanggang-Huangmei High-Speed Railway as an example and taking deflection of the third principal stress of the surrounding rock at a vault after tunnel excavation as the criterion,the critical buried depth of the large section tunnel was determined.Then,the strength reduction method was employed to calculate the tunnel safety factor under different rock classes and thickness-span ratios,and mathematical statistics was conducted to identify the relationships of the tunnel safety factor with the thickness-span ratio and the basic quality(BQ)index of the rock for different rock classes.Finally,the influences of thickness-span ratio,groundwater,initial stress of rock and structural attitude factors were considered to obtain the corrected BQ,based on which the stability of a large cross-section tunnel with a depth of more than 100 m during mechanized operation was analyzed.This evaluation method was then applied to Liuyuan Tunnel and Cimushan No.2 Tunnel of Chongqing Urban Expressway for verification.Findings-This study shows that under different rock classes,the tunnel safety factor is a strict power function of the thickness-span ratio,while a linear function of the BQ to some extent.It is more suitable to use the corrected BQ as a quantitative index to evaluate tunnel stability according to the actual conditions of the site.Originality/value-The existing industry standards do not consider the influence of buried depth and span in the evaluation of tunnel stability.The stability evaluation method of large section tunnel considering the correction of overburden span ratio proposed in this paper achieves higher accuracy for the stability evaluation of surrounding rock in a full or large-section mechanized excavation of double line high-speed railway tunnels.

基于RRT算法的移动机器人安全光滑路径生成

在多障碍物复杂工厂环境中,针对快速探索随机树算法(RRT)生成的路径存在冗余点、贴近障碍物且存在锯齿状转折的问题,改进得到了安全-光滑RRT(Safe-SmoothRRT)路径规划算法。首先,引入目标偏置策略;其次,该算法利用融合目标点引力思想的新节点扩展方式以及改进的近邻点度量策略以减少树的盲目扩展,提高生长的目标性;随后,引入节点安全约束,将安全节点加入树中;改进路径简化方法,剔除冗余点的同时兼顾了安全性;最后通过B样条局部平滑来改善路径的平滑性。在MATLAB仿真实验中分别与标准RRT算法、自适应目标偏向性RRT算法和改进RRT算法相比,在平均路径长度方面最大下降了7.1%,在平均有效节点数方面最大下降了64.1%,且所得路径始终与障碍物保持一定的安全距离,结果表明改进算法有效提升了路径的光滑性和安全性。

技术市场发展能否促进企业技术要素配置——基于中国上市公司样本的实证研究

技术市场是企业配置技术要素的重要场域,它通过支撑企业技术创新全过程和促进产业结构升级两条路径影响企业技术要素配置水平。市场中用户的厚度和交易安全性一方面对企业提供效用激励,另一方面调节用户风险感知程度,进而在机制上影响企业的市场交易行为。基于上市企业数据实证分析的结论表明:技术市场厚度和安全度与上市企业技术要素配置正相关,但这种正相关受到融资约束的调节。在较高融资约束水平的情况下,技术市场安全对企业技术要素配置水平的影响作用更显著;而低融资约束情况下,技术市场厚度对企业技术要素配置水平的影响更显著。

基于公式化限额和最小裕度最大化的电网热稳定限额计算

编制热稳定控制限额是电网调度控制中心的重要工作,也是保障电网安全运行的重要手段。针对新能源大规模并网后潮流不确定性大导致热稳定限额制定难度增大的问题,以预想故障分析为基础计算潮流转移关系并建立电网安全约束,进而提出了基于公式化限额和最小裕度最大化的三阶段电网热稳定限额计算方法,实现了热稳定限额的批量自动计算。第1阶段对输电通道限额进行初始化,第2阶段对故障后易过载的通道按照故障后不超瓶颈设备短时载流能力制定公式化限额要求,第3阶段对转移关系约束存在耦合的通道集合逐次按最小裕度最大化原则计算通道控制限额。对输电资源紧张的通道同时采用公式化限额和通道控制限额要求可以减小保守性,充分释放通道输电能力;对其余通道只采用通道控制限额要求,可减少并简化控制要求。以某区域电网2023年夏季高峰运行方式为例,限额自动计算结果与稳定规程的一致性较好,验证了所提方法的有效性。

基于模型预测的膝关节置换手术机器人柔顺控制

针对半主动型膝关节置换手术机器人的柔顺跟随医生意图运动和手术安全范围约束问题,提出了一种模型预测导纳控制算法.首先,为了提高算法运行效率,使用斯特林插值方法对机械臂动力学模型进行线性化,并作为预测模型,该方法计算简单且求解精度高;其次,基于导纳模型力柔顺控制机理识别操作医生的力意图生成机械臂期望运动轨迹;然后,设计虚拟状态,提高模型预测控制算法的显式处理约束能力,利用模型预测控制的滚动优化和反馈校正特性提高控制鲁棒性;最后,结合成机械臂模型预测导纳控制器.设计三环PID(Proportional integral derivative)控制对照试验,验证了模型预测控制算法的轨迹跟踪性能更好,可以更好的实现期望的导纳动态,从而得到更优的柔顺效果.在此基础上,进一步验证模型预测导纳控制器在具有强耦合性、复杂系统参数结构特性的机械臂上的主动约束效果.结果表明模型预测导纳控制算法能实现比传统三环PID控制更好的柔顺性,且具备满足膝关节置换手术需求的安全性.本文有望促进半主动手术机器人的实际应用.

Intelligent Power Grid Load Transferring Based on Safe Action-Correction Reinforcement Learning

When a line failure occurs in a power grid, a load transfer is implemented to reconfigure the network by changingthe states of tie-switches and load demands. Computation speed is one of the major performance indicators inpower grid load transfer, as a fast load transfer model can greatly reduce the economic loss of post-fault powergrids. In this study, a reinforcement learning method is developed based on a deep deterministic policy gradient.The tedious training process of the reinforcement learning model can be conducted offline, so the model showssatisfactory performance in real-time operation, indicating that it is suitable for fast load transfer. Consideringthat the reinforcement learning model performs poorly in satisfying safety constraints, a safe action-correctionframework is proposed to modify the learning model. In the framework, the action of load shedding is correctedaccording to sensitivity analysis results under a small discrete increment so as to match the constraints of line flowlimits. The results of case studies indicate that the proposed method is practical for fast and safe power grid loadtransfer.

电力市场环境下可靠性机组组合机制

完善的双边现货市场是实现电力市场优化资源配置功能的关键,可靠性机组组合是双边现货市场环境下满足日内发电容量充裕度等可靠性要求的重要手段。探讨集中式市场环境下可靠性机组组合的组织方式、出清模型与结算机制。总结国内外各典型电力市场中可靠性机组组合相关机制设计,得到可靠性机组组合机制设计的一般思路。通过算例分析对比各可靠性机组组合出清模型下的市场绩效。基于数值仿真与理论分析结果为中国可靠性机组组合机制设计提供建议。

氨冷库充注量优化及安全评估的研究进展

为了降低氨冷库充注量、提高冷库安全性,本文从氨制冷系统的充注量和安全管控两个方面进行了分析,发现可以从优化换热器、辅助设备、采用直接膨胀供液方式、低循环倍率的氨泵供液以及间接制冷等方面降低氨充注量,制冷剂的充注量的测量、故障诊断是制冷系统高效稳定运行的有力保障。此外,比较分析了应用于氨制冷系统的多种安全评估方法的优缺点,评估方法选取合理与否会直接影响最终的预测结果。最后,对制约降氨技术推广的因素进行了客观分析,并提出了相应的建议。

考虑安全性风险的电热氢系统优化配置方法

电热氢系统作为一种高效的综合能源供用系统受到广泛关注。然而,氢气的燃爆特性导致了其面临着安全性挑战。为此,提出了考虑安全性风险的电热氢系统优化配置方法。首先,分析电热氢系统的安全性,对电解槽和燃料电池的工作范围和工作温度进行约束;然后,基于氢气的非理想气体压强公式对储氢罐压强进行更为准确地约束,并基于TNT当量法量化了储氢罐的安全性风险;最后,通过安全风险系数,将储氢罐的安全风险折算进目标函数中,建立了以系统投资成本、运行成本和安全性风险为优化目标的电热氢系统优化配置模型,并利用禁忌混沌量子粒子群算法进行求解。算例结果表明,在考虑安全性风险的情况下,通过合理的容量设计,可以在提高系统经济性的同时有效降低系统安全风险,进而验证了该优化设计方法的有效性。

计及同步机惯性与储能虚拟惯性价值的电能、惯性及一次调频联合优化出清模型

高比例新能源发电并网将导致电力系统同步机惯性和频率响应资源减少,大扰动下电力系统频率安全问题凸显。目前,现货市场缺乏机制来激励惯性资源供应,而同步机惯性和储能虚拟惯性本身具有一定价值,因此可以考虑将他们纳入现货市场进行出清,以有效地维持系统频率稳定。为此,该文首先探讨同步发电机和储能提供惯性与一次调频的区别,并基于储能虚拟惯性延时推导两阶段响应过程的频率安全约束;其次,提出计及同步机惯性“块状”特性与储能能量预留系数的电能、惯性及一次调频日前出清模型,获取同步机惯性和虚拟惯性价值;最后,基于算例验证所提模型的有效性,并讨论不同参数设置对于出清结果的影响。

省间中长期市场连续运营下考虑耦合安全约束的电力交易联合优化出清模型

为提高省间中长期电力市场连续运营效率,设计了考虑耦合安全约束的省间中长期交易联合出清模型。在交易准备环节、预出清环节、联合出清环节递进考虑了各类安全约束,包括发电机组能力约束、输电通道能力约束、省级送出受入节点能力约束和电力电量平衡约束。在出清成交结果阶段,以调减电量最小为目标,将同一批次进入安全校核且存在时空交集的多笔交易联合出清,高效地处理了各类安全约束特别是耦合性安全约束对交易结果产生的影响,提高了交易结果的可执行性,通过算例验证了联合优化出清方式的有效性。算例结果表明,联合出清方式能够在满足各类安全约束的条件下高效出清形成成交结果,有利于购售方市场主体共同承担安全约束影响,保障发电输电能力充分利用和市场主体利益。

化工安全仪表系统SIL验证的工程应用

化工厂安全仪表系统在项目投入使用前,必须进行安全完整性等级(SIL)验证工作,以此来验证安全仪表功能是否达到设计的风险降低要求。以某化工厂安全仪表系统SIL验证为例,研究SIL验证在工程中的应用,包括验证的步骤、方法;并讨论检验测试覆盖率(CTI)、检验测试间隔(TI)等参数对验证结果的影响,通过合理地调整这些参数可以使验证结果得到优化。

考虑源网荷储协调优化的安全约束机组组合

应对高渗透率的风电光伏不确定性要求充分发挥各种资源的灵活性,因此从传统的柔性资源,如具有快速上升/下降旋转储备的火电机组和输电线路传输切换出发,提出了一种具有多个柔性资源的安全约束机组组合模型。该模型将需求响应、输电线路传输切换及公共储能集成在一个集成方案中,通过协调优化源网荷储侧的这些柔性资源,以应对风电光伏出力和系统元件偶发故障的不确定性。针对这一大而复杂的计算问题,提出了一种新的加速分解技术,旨在提高模型求解效率,减少迭代次数和CPU计算时间。

屈曲约束支撑在抗震设防裂度为9度地区的施工技术

我国已建或在建的房屋建筑工程,无论是民用建筑还是工业建筑,由于国内各地地震频发,导致对房屋结构的抗震能力需要着重考虑。笔者基于西昌市马道城中村棚户区改造项目中的商业综合楼的设计与建设,阐述了屈曲约束支撑在9度地震设防烈度地区的应用。

Two-echelon inventory model with service level constraint and controllable lead time sensitive to order quantity

The decision-making and optimization of two-echelon inventory coordination were analyzed with service level constraint and controllable lead time sensitive to order quantity.First,the basic model of this problem was established and based on relevant analysis,the original model could be transformed by minimax method.Then,the optimal order quantity and production quantity influenced by service level constraint were analyzed and the boundary of optimal order quantity and production quantity was given.According to this boundary,the effective method and tactics were put forward to solve the transformed model.In case analysis,the optimal expected total cost of two-echelon inventory can be obtained and it was analyzed how service level constraint and safety factor influence the optimal expected total cost of two-echelon inventory.The results show that the optimal expected total cost of two-echelon inventory is constrained by the higher constraint between service level constraint and safety factor.