Safety analysis of wheel brake system based on STAMP/STPA and Monte Carlo simulation

The wheel brake system safety is a complex problem which refers to its technical state, operating environment, human factors, etc., in aircraft landing taxiing process. Usually, professors consider system safety with traditional probability techniques based on the linear chain of events. However, it could not comprehensively analyze system safety problems, especially in operating environment, interaction of subsystems, and human factors. Thus,we consider system safety as a control problem based on the system-theoretic accident model, the processes(STAMP) model and the system theoretic process analysis(STPA) technique to compensate the deficiency of traditional techniques. Meanwhile,system safety simulation is considered as system control simulation, and Monte Carlo methods are used which consider the range of uncertain parameters and operation deviation to quantitatively study system safety influence factors in control simulation. Firstly,we construct the STAMP model and STPA feedback control loop of the wheel brake system based on the system functional requirement. Then four unsafe control actions are identified, and causes of them are analyzed. Finally, we construct the Monte Carlo simulation model to analyze different scenarios under disturbance. The results provide a basis for choosing corresponding process model variables in constructing the context table and show that appropriate brake strategies could prevent hazards in aircraft landing taxiing.

Acupuncture for cerebral palsy: a meta-analysis of randomized controlled trials

OBJECTIVE： To evaluate the efficacy and safety of acupuncture therapy for children with cerebral palsy. DATA SOURCES： We conducted electronic searches of PUBMED（1950/2017）, EMBASE（1974/2017）, Science Direct（1986/2017）, Academic Source Premier（1887/2017）, the Cochrane Library（Issue 4, April 2017）, Science Citation Index Expanded（1900/2017）, China National Knowledge Infrastructure（1915/2017）, China Biological Medicine（1990/2017-04）, Wan Fang（1980/2017）, VIP（1989/2017）, and Chinese Science Citation Database（1989/2017）. DATA SELECTION： We included randomized controlled trials that aimed to compare the effect of acupuncture plus rehabilitation training versus rehabilitation training alone. Data about functional motor abilities, daily activity/social participation, effective rate, intellectual development, and adverse effects were included. We used Revman 5.2 software for statistical analysis. OUTCOME MEASURES： The primary outcomes included functional motor abilities, daily activity, and effective rate. The secondary outcomes included intellectual development and adverse effects.RESULTS： Twenty-one studies with a total of 1718 participants met the inclusion criteria. The effect size of gross motor function（SMD = 0.64, 95% CI： 0.52 to 0.76, P 〈 0.00001; I^2 = 0%, P = 0.69; in 13 studies with 1144 patients） and the total effective rate（RR = 1.28, 95% CI： 1.20 to 1.37, P 〈 0.00001; I^2 = 18%, P = 0.27; in 12 studies with 1106 patients） suggested that acupuncture plus rehabilitation produced a significant improvement in gross motor function and a high total effective rate. The pooled fine motor function（SMD = 3.48, 95% CI： 2.62 to 4.34, P 〈 0.00001; I^2 = 64%, P = 0.10; in 2 studies with 193 patients）, modified Ashworth scale scores（SMD = –0.31, 95% CI： –0.52 to –0.11, P = 0.003; I^2 = 74%, P = 0.004; in 5 studies with 363 patients） and activities of daily living（SMD = 1.45, 95% CI： 1.20 to 1.71, P 〈 0.00001; I^2 = 78%, P = 0.004; in 4 studies with 313 patients） also indicated improvements in children with cerebral palsy. Publication bias was not observed. Only mild adverse events related to acupuncture were reported. CONCLUSION： Acupuncture plus rehabilitation training improved gross motor function, reduced muscle spasms, and enhanced daily life activities in children with cerebral palsy. However, this conclusion should be interpreted with caution due to the small number of randomized controlled trials available and the small sample sizes. More high-quality and large-scale studies are needed.

Early filiform needle acupuncture for poststroke depression: a meta-analysis of 17 randomized controlled clinical trials

OBJECTIVE： To evaluate the effectiveness and safety of filiform needle acupuncture for poststroke depression, and to compare acupuncture with the therapeutic efficacy of antidepressant drugs. DATA RETRIEVAL： We retrieved data from the Chinese National Knowledge Infrastructure （1979-2012）, Wanfang （1980-2012）, VIP （1989-2012）, Chinese Biomedical Literature （1975- 2012）, PubMed （1966-2012）, Ovid Lww （-2012）, and Cochrane Library （-2012） Database using the internet. SELECTION CRITERIA： Randomized controlled trials on filiform needle acupuncture versus antidepressant drugs for treatment of poststroke depression were included. Moreover, the in- cluded articles scored at least 4 points on the Jadad scale. Exclusion criteria： other acupuncture therapies as treatment group, not stroke-induced depression patients, score 〈 4 points, non-ran- domized controlled trials, or animal trials. MAIN OUTCOME MEASURES： These were the Hamilton Depression Scale scores, clinical ef- fective rate, Self-Rating Depression Scale scores, Side Effect Rating Scale scores, and incidence of adverse reaction and events. RESULTS： A total of 17 randomized controlled clinical trials were included. Meta-analysis results displayed that after 4 weeks of treatment, clinical effective rate was better in patients treated with fill- form needle acupuncture than those treated with simple antidepressant drugs [relative risk = 1.11, 95% confidence interval （C/）： 1.03-1.21, P = 0.01]. At 6 weeks, clinical effective rate was similar between filiform needle acupuncture and antidepressant drug groups. At 2 weeks after filiform needle acupuncture, Hamilton Depression Scale （17 items） scores were lower than in the antide- pressant drug group （mean difference = -2.34, 95%CI： -3.46 to -1.22, P 〈 0.000,1）. At 4 weeks, Hamilton Depression Scale （24 items） scores were similar between filiform needle acupuncture and antidepressant drug groups. Self-Rating Depression Scale scores were lower in filiform needle acupuncture group than in the antidepressant drug group. Side Effect Rating Scale was used in only two articles, and no meta-analysis was conducted. Safety evaluation of the 17 arti- cles showed that gastrointestinal tract reactions such as nausea and vomiting were very common in the antidepressant drug group. Incidence of adverse reaction and events was very low in the filiform needle acupuncture group. CONCLUSION： Early filiform needle acupuncture for poststroke depression can perfectly con- trol depression. Filiform needle acupuncture is safe and reliable. Therapeutic effects of filiform needle acupuncture were better than those of antidepressant drugs.

Safety control strategy for vertebral lamina milling task

Vertebral lamina milling task is one of the high-risk operations in spinal surgeries. The operation is to remove part of vertebral lamina and release the pressure on the spinal nerve. Because many important vessels and nerves are under the vertebral lamina, any incorrect operation may cause irreparable damage to patients. To improve the safety of lamina milling task, a fuzzy force control strategy is proposed in this paper. Primary experiments have been conducted on bone samples from different animals. The results show that, with the fuzzy force control strategy, the bone milling system can recognize all surgery states and halt the tool at the proper location, achieving satisfactory surgery performance.

Intelligent Diagnostic Method for Ageing Analysis of Transformer

The fuzzy method is proposed for ageing analysis of transformer. The fuzzy controller is used for various input and one output, strictly depends on the number of membership function and there rule base and the type of the defuzzification method. The ageing of transformers is influenced by short term and long term over loads, number and intensity of short circuits, incidence of lightning, and internal faults. The recent development of various techniques for detecting the incipient fault conditions have been improved to some extent;the life expectancy of transformers by resorting to corrective actions in time. The ageing behavior is likely to be different for different types of transformers. The life span of the transformer, thus depends initially on the design and quality of manufacture and later on service conditions and maintenance standard, these factors vary considerably and affect the useful span of service life which therefore needs to be taken into account for residual life assessment. During the natural ageing of transformers, the insulation of winding deteriorates. Cellulose insulation degrades due to heating or electrical breakdown which is dissolved in oil. Hence, the chemical analysis of the Transformer oil gives evidence of changes that are taking place in the winding insulation during operation. Deterioration in transformer cellulose decreases both its electrical and mechanical strength. In this paper a novel fuzzy based algorithm has been implemented on three samples of power transformer oil.

Direct and Inverse Kinematic Analysis of a Leg-wheeled Passive Wheel Mobile Robot - Ice-skater Robot

A new passive wheel type of leg-wheeled mobile robot based on rolling principle was introduced. To enhance the stability and maintain vertical to the ground of wheels, four passive wheels were installed at the end of four legs respectively and parallel mechanisms were used as legs. And an inertia coordinate system and a robot coordinate system were established, the related kinematic equation of the robot was gotten according to some assumptions after the configuration or the posture of wheels and legs was analyzed. At the same time, the turning conditions of the robot were also obtained. Based on the motion principle, the VSS-based logic control system was designed and the skating straight experiments and the turning experiments were conducted. And some conclusions were drawn.

Radiotherapy reliability analysis based on PSA method

The reliability of radiotherapy was evaluated and effective approaches were obtained in order to improve radiotherapy quality by using the Probabilistic Safety Assessment(PSA) method. This study investigated the feasibility of the PSA method being applied to radiotherapy through Image-guided Radiotherapy(IGRT) and chest tumor irradiation. A fault tree has been constructed after analyzing causal relationship of the events.After calculating Risk A, a total inaccuracy radiotherapy probability and the importance of all base events were obtained. The probability of inaccurate radiotherapy was 2.87%. Under the condition that the target delineation was perfectly right, the accuracy of radiotherapy significantly improved. With the calculation without Conebeam Computed Tomography(CBCT) being corrected before irradiation, the accuracy significantly decreased.The most important events were connected with the human factor. Improving human technical level could enhance radiotherapy quality control efficiently.

2021—2023年全国化工安全事故统计分析及防控措施

对2021年1月—2023年4月期间全国化工安全事故数量及死亡人数进行了数理统计,并从发生区域、所属行业、所在园区等级等方面分析了事故特征;从事故类别、事故作业情况、事故等级等方面分析了事故性质,探寻化工安全事故的特点及规律。通过分析发现:2021年1月—2023年4月全国化工安全事故多发生在精细化工企业,多以设备失效和检修作业为直接原因。基于分析结论提出了防范措施,为今后降低化工安全事故概率提供参考依据。

不同海况条件下舰载无人机着舰安全分析

针对无人机上舰的使用需求,本文对舰载无人机着舰开展了系统的研究。建立了机-舰-环境综合模型和舰载无人机全自动着舰引导控制系统;基于建立的舰载无人机着舰综合模型对不同海况下的着舰过程进行仿真分析,研究不同海况条件以及航母不同航速和遭遇角对着舰安全的影响。仿真研究表明:在复杂海况下,航母可通过适当提高航速以获得更高的着舰成功率,但过高的航速会导致舰尾流扰动加剧,使得着舰成功率显著下降;通过对仿真结果进行统计分析,给出了不同海况下的着舰安全范围,为无人机着舰辅助决策提供参考。

基于CLPN的系统安全性分析方法

随着安全性攸关系统的智能化、自动化发展,系统规模和复杂度急剧增加,传统基于链式/树式安全性因果模型的安全性分析方法在非线性致危因素、非失效致危因素分析方面存在很大的局限性,现代基于系统理论的安全性因果模型虽然在航空航天、核电能源等多个领域得到有效性验证,但目前该类方法尚缺乏严格统一的分析步骤和自动化分析工具。为此,提出复杂系统控制过程的建模工具——控制逻辑Petri网(CLPN),对控制过程中的活动及其之间的交互影响关系进行形式化描述,并对系统CLPN模型的可达图进行失效扩展,在不影响安全性分析的前提下尽量避免因失效事件建模造成的分析模型规模激增。基于CLPN模型,以系统理论事故模型与过程(STAMP)系统安全性因果模型危险因素分类为标准,在可达性分析的基础上对作为系统致危因素的危险控制活动进行探索,实现系统安全性的自动化分析。最后,通过实例分析和方法对比,对所提方法的可用性和有效性进行验证。实验结果表明,基于CLPN的系统安全性分析方法在结果完备性和分析效率方面具有较大的优势。

区域水库群防汛安全风险快速评估及预警

近年来极端气候事件频发,给人类自身安全和整个社会经济带来深刻影响,对区域防洪响应提出了更高层次的要求,区域水库群防汛安全风险快速评估方法需求日益增加。本文在传统风险分析评估的基础上,引入瑞利信号衰落模拟风险信号的传播,通过风险概率联合分布描述水库风险关联性,分析了区域水库群防汛风险分布影响,初步建立了定量的区域水库群风险率计算模式,并将其应用于“22·6”北江特大洪水过程,分析了韶关地区的区域水库风险情况,结果表明,区域风险分布符合实际,模型简单且计算效率较高,实现了对区域水库群防汛安全风险快速评估及预警,同时可为今后防御流域洪水及水旱灾害防御工作提供参考借鉴,以提高区域水库群应对极端气候条件下洪涝灾害的能力。

脉冲强光技术对食品加工品质的影响及安全控制技术研究进展

脉冲强光是一类新兴的非热处理技术,该装置以稀有气体被电离后释放高能量的脉冲光来降低固体表面或液态食品中的微生物负载量,从而延长食品的货架寿命,且对多种营养成分造成不明显的破坏,还可以改良部分食品的理化性质和感官品质,这弥补了传统热力杀菌方法与化学杀菌方法的缺陷。脉冲强光中的光化学效应、光热效应被认为是降低食品中微生物负载量的主要机制。综合多方面的研究,脉冲强光技术在食品加工和安全控制中均取得了较好的处理效果。该研究主要综述了脉冲强光技术在食品加工和安全控制方面的应用进展,评价了不同脉冲强光处理对食品品质中部分理化指标的变化情况,最后展望了脉冲强光技术的前景与该技术的部分不足之处,为脉冲强光技术在食品工业领域广泛应用提供参考。

A Logic-Based Safety Analysis Algorithm for Discretionary Access Control

For the issue of the discretionary access control（DAC） model safety analysis,a logic method is proposed.This method takes the GD model as the classic DAC model and Prolog as the basic language to describe system states and state transfer rules.A general program based on this logic method is proposed for DAC safety analysis,but this program may never be terminal for some safety analysis goal.The safety analysis algorithm is achieved by simplifying the general program according to the property of the DAC model state transfer rules.This safety analysis algorithm is easier to understand and implement than the previous algorithms and its time complexity is O（N＋M＋T）,in which N,M,and T are the numbers of the rights with copy flag,the policies for right transferring,and the policies for right permitting,respectively.

正念减压疗法和正念认知疗法安全性的meta分析

目的:探讨正念减压疗法(MBSR)和正念认知疗法(MBCT)相关不良事件及影响因素。方法:检索PubMed、CINAHL、Embase、WebofScience、Scopus、Proquest、ScienceDirect、PsycINFO数据库及未发表的研究报告和灰色文献中有关MBSR和MBCT不良事件或不良反应的随机对照试验,并追溯纳入文献的参考文献和相关期刊,检索时限截止到2022年6月1日。采用RevMan5.4软件进行meta分析,计算合并OR(95%CI)值。结果:共纳入15篇文献,包含2841名研究对象。Meta分析结果显示,MBSR或MBCT干预组和对照组发生不良事件或不良反应的差异有统计学意义(0R=2.48,95%CI=1.09~1.61;P<0.05);使用的正念干预方法(单独使用MBSR,OR=9.04,95%CI=5.34~15.30)、参与者合并基础疾病(合并精神疾病,OR=1.49,95%CI=1.12~1.97;合并躯体疾病,OR=8.65,95%CI=5.17~14.45)、练习强度(每次>2h,OR=1.43,95%CI=1.04~1.96)及正念师资水平(未经过规范培训,OR=1.96,95%CI=1.20~3.23)是影响MBSR和MBCT治疗过程中可能会出现相关不良事件或不良反应的因素。结论:正念减压治疗或正念认知治疗过程中可能会出现不良事件或不良反应。

新兴能源基础设施安全风险分析与防控体系

“双碳”背景下,随着终端电气化水平和氢能利用占比的逐步提高,新兴能源基础设施呈现爆发性增长趋势,与此同时,安全事故频发,安全问题不断凸显,制约了产业的健康发展。对以储能站、充电站、加氢站、综合能源站等为代表的新兴能源基础设施的主要安全风险要素进行了全面梳理,剖析了当前全环节、全链条安全风险认知、防控、监管方面存在的问题和挑战,并进一步总结了新兴能源基础设施安全风险及防控的共性现状和总体形势。在此基础上,从安全防控技术创新、多利益相关方监管、公共安全保障体系建设等维度提出了安全防控体系性框架和应对措施,为我国新兴能源基础设施的安全防控与保障提供支撑和参考。

胰高血糖素样肽1受体激动剂治疗合并超重或肥胖的2型糖尿病的疗效和安全性的Meta分析

目的系统评价胰高血糖素样肽1受体激动剂(GLP-1RA)治疗合并超重或肥胖2型糖尿病(T2DM)患者的有效性与安全性。方法计算机检索PubMed、Embase、Cochrane Library、Ovid、ClinicalTrial.gov、SinoMed、CNKI、WanFang Data和VIP数据库,搜集有关GLP-1RA治疗T2DM合并超重或肥胖患者的随机对照试验(RCT),检索时限均从2005年1月1日至2023年11月1日。由2位研究者独立筛选文献、提取资料并评价纳入研究的偏倚风险后,采用R软件进行Meta分析,并采用GRADE系统进行证据质量评价。结果共纳入71个RCT,包括29476例患者。Meta分析结果显示,相比于其他降糖药,GLP-1RA在改善糖化血红蛋白[WMD=-0.55,95%CI(-0.65,-0.45),P<0.001]、减重[WMD=-2.61,95%CI(-3.25,-1.97),P<0.001]方面均具有优势;GLP-1RA对空腹血糖的改善效果呈时间依赖性[16周以内:WMD=0.25,95%CI(-0.17,0.66),P=0.250;16~52周:WMD=-0.06,95%CI(-0.32,0.20),P=0.650;>52~104周:WMD=-1.67,95%CI(-1.91,-1.43),P<0.001];安全性方面,GLP-1RA的总体不良反应发生率较高[RR=1.11,95%CI(1.07,1.15),P<0.001];但低血糖发生率低于胰岛素[RR=0.58,95%CI(0.48,0.71),P<0.001],而与口服降糖药的差异无统计学意义[RR=0.83,95%CI(0.58,1.19),P=0.310]。GRADE系统评价显示,仅低血糖发生率的证据等级为中等,其余结局指标的证据水平均为低级。结论当前证据显示,对于T2DM合并肥胖或超重患者,GLP-1RA尤其是司美格鲁肽相比于安慰剂、胰岛素或口服降糖药,能更有效兼顾降糖和减重,虽总体不良反应较多,但可减少低血糖发生。

城市轨道交通全自动运行场景下的智能管控平台研究

[目的]现有运营机制主要为运营管理制度驱动人员进行操作管理,运营人员通过电话或对讲设备沟通信息,并使用各自独立的专业系统下达运营管控指令,在系统与系统之间只有少数固定的联动,这种模式下运营管理人员负荷较高,阻碍了运营管控效率的进一步提升。研究全自动运行中严重影响运营、乘客、设备设施等安全的场景,探索全自动运行运营安全管控机制和智能管控平台,提升全自动运行线路运营安全管控水平。[方法]采用智能化、数字化、信息化、高可信等技术手段将静态的运营规则和工作制度提升为动态的联动联控和应急处置管控措施的方法;构建服务于车站、车辆以及中心调度等多岗位信息共享、协同处置机制和智能管控平台,提高故障应急处置以及排故效率。[结果及结论]上海全自动运行线路的实践证明,搭建运营安全智能管控平台,加强运营安全监督、构建关键岗位协同处置机制、实现制度驱动系统安全高效地进行专业设施设备联动联控、智能辅助决策等功能,能更好地保障和提升全自动运行线路的应急处置效率和运营安全管控水平。

基于扎根理论与灰色关联分析的养殖户疫病规范防治素养提升研究

为了进一步提升养殖户疫病规范防治素养,保障疫病规范防治工作的有序开展,本研究以宁夏回族自治区中宁县、海原县、原州区和西吉县共25个肉牛养殖户的访谈资料为基础,运用扎根理论对21个养殖户的访谈资料进行开放式编码、主轴编码和选择性编码,利用剩余4个养殖户的访谈资料进行理论饱和度检验,构建养殖户疫病规范防治素养提升逻辑模型,同时对养殖户疫病规范防治素养关键提升因子进行灰色关联分析。结果表明:通过开放式编码、主轴编码和选择性编码,从中提炼出31个原始概念、17个初始范畴和5个主范畴。4个养殖户访谈资料的理论饱和度检验结果显示已达到理论性饱和。养殖户防疫认知、畜禽健康程度、周围环境作用、政府治理和市场治理5个主范畴是提升养殖户疫病规范防治素养的主要因子,其中养殖户防疫认知和畜禽健康程度是内在关键提升因子,周围环境作用、政府治理和市场治理是外在关键提升因子。通过对5个主范畴进行灰色关联分析,得到了养殖户疫病规范防治素养关键提升因子的排序为政府治理>周围环境作用>养殖户防疫认知>市场治理>畜禽健康程度。基于此,笔者提出注重畜禽健康程度,提高养殖户防疫认知;加大防疫宣传力度,改善养殖户周围环境;加强疫病防控措施,调整养殖户知识结构是提升养殖户疫病规范防治素养的有效途径。

基于安全性的电动垂直起降飞行器飞控系统架构设计

飞行控制系统作为电动垂直起降(electric vertical take-off and landing,eVTOL)飞行器的关键机载系统,需要具备和民机同样的安全性。为了设计满足eVTOL飞行器需求的飞控系统架构,根据适航规章梳理了安全性要求,并基于安全性要求介绍了eVTOL飞行器飞控系统飞控计算机、传感器和作动器余度设计技术,设计了一种基于安全性考虑的eVTOL飞行器飞控系统架构;分析了eVTOL飞行器旋翼构型下的典型功能危险,并采用故障树进行了安全性分析。结果表明,设计的飞控系统架构的典型功能危险能够满足失效概率的要求。