基于多源数据融合的网络风险评估

鉴于网络安全事件采集的多源性,提出了基于多源数据融合的网络风险评估方法。旨在研究如何处理具有不确定因素的海量的多源数据以及如何对网络进行风险评估。把D-S证据理论应用于风险评估的数据融合阶段,同时结合主机攻击成功发生率和主机内部脆弱性及相应的权重值,计算出某一个时段网络的整体风险值,使网络管理员可以动态地调整安全控制措施的优先级。试验结果表明了该方法的可行性和有效性。     

潜艇通信浮标系统通信效能评估指标体系研究

从通信浮标的系统功能特性和潜艇通信保障军事需求出发,结合潜艇作战的特殊性,以业务性能指标和战术性能指标为基础构建了通信浮标指标体系模型。该模型可以对潜艇使用通信浮标时对通信浮标的基本通信保障能力进行较为全面的评估。     

基于BP神经网络的桥梁技术状态评估

用养护规范中17个评价指标作为输入层网络神经元,把桥梁损伤等级参数作为输出层神经元,建立了桥梁评估3层BP神经网络模型。选用湖北省110座旧桥的评估数据作为训练样本,后10个作为测试样本,经过2068次迭代运算的网络训练,得到了误差满足精度要求的收敛网络。将待评估的桥梁参数输入训练好的网络,得到评估桥梁的技术状态等级。     

自升式移动平台结构安全评估研究

文章介绍了自升式移动平台结构安全评估的目的、依据和流程,重点论述了结构技术状况评估和结构计算的内容,并通过实例对其进行了说明。结构安全评估要确定平台目前的结构技术状况,找出结构存在的问题,提出解决的方案,为平台管理者的科学决策提供依据。评估要求建立平台的数据库,可为今后平台的应急响应提供及时的服务。结构安全评估对平台的安全运营和科学管理具有重要意义。     

基于贝叶斯网络的船舶人因安全性评估模型

针对舰船系统特点,设计了相应的人因安全性调查问卷,确定人因安全性影响因素、节点状态和条件概率.建立基于贝叶斯网络的船舶人因安全性量化评估模型,据此对影响安全性的因素进行灵敏度分析.结果表明,提出的安全性量化评估模型和分析方法正确、可行、有效.     

基于心理安全距离的行人风险评价及预警算法研究

为实现在机非混行的交通环境下,对动态、随机弱势道路使用者的准确风险评估,基于行车安全场理论提出了考虑行人心理安全距离的碰撞行人风险评价模型.首先通过考虑行驶车辆是否会危及行人的心理安全,提出了心理安全距离的概念,包括心理安全通行距离和心理安全制动距离2个方面,并通过问卷调研挖掘其可能的影响因素进行数值分析;接着将心理安...     

内转塔单点系泊系统风险评估与设计维护建议

内转塔系泊系统广泛应用于海洋石油FPSO或液化天然气FLNG中。在我国南海海域油田开发中,内转塔系泊系统发挥了重要作用,并已逐渐成为主要的FPSO系泊方式。本文对"海洋石油111"FPSO内转塔系泊系统的失效模式、主要风险因素等进行了分析。通过风险评估确认了主要风险点,对该系统的设计和维护提出了相应的建议。     

Adding temporal information to direct-demand models: Hourly estimation of bicycle and pedestrian traffic in Blacksburg,VA

Cycling and walking are environmentally-friendly transport modes, providing alternatives to automobility. However, exposure to hazards (e.g., crashes) may influence the choice to walk or cycle for risk-averse populations, minimizing non-motorized travel as an alternative to driving. Most models to estimate non-motorized traffic volumes (and subsequently hazard exposure) are based on specific time periods (e.g., peak-hour) or long-term averages (e.g., Annual Average Daily Traffic), which do not allow for estimating hazard exposure by time of day. We calculated Annual Average Hourly Traffic estimates of bicycles and pedestrians from a comprehensive traffic monitoring campaign in a small university town (Blacksburg, VA) to develop hourly direct-demand models that account for both spatial (e.g., land use, transportation) and temporal (i.e., time of day) factors. We developed two types of models: (1) hour-specific models (i.e., one model for each hour of the day) and (2) a single spatiotemporal model that directly incorporates temporal variables. Our model results were reasonable (adj-R² for the hour-specific [spatiotemporal] bicycle model: ∼0.47 [0.49]; pedestrian model: ∼0.69 [0.72]). We found correlation among non-motorized traffic, land use (e.g., population density), and transportation (e.g., on-street facility) variables. Temporal variables had a similar magnitude of correlation as the spatial variables. We produced spatial estimates that vary by time of day to illustrate spatiotemporal traffic patterns for the entire network. Our temporally-resolved models could be used to assess exposure to hazards (e.g. air pollution, crashes) or locate safety-related infrastructure (e.g., striping, lights) based on targeted time periods (e.g., peak-hour, nighttime) that temporally averaged estimates cannot.     

无资料旧桥重型交通车辆安全评估检测研究

某待安全评估桥梁是一座无法找到设计及检测资料的4跨简支T梁桥,由于工程建设的需要,在工程实施期间作为交通疏解要道,该桥计划需要通行包括泥头车、平板车等在内的重型交通车辆。为保障施工期间桥梁使用安全性能并获取承载能力数据,以该无资料旧桥通行重型车辆安全评估检测为背景,首先从理论上计算判断通行的可行性,然后通过试验对理论计算的通行能力进行论证,最终得到了安全评估结果。文中采用的安全评估方法可为类似项目提供有益参考。     

A causal encounter model of traffic collision avoidance system operations for safety assessment and advisory optimization in high-density airspace

The traffic collision avoidance system (TCAS) acts as a proverbially accepted last-resort means to resolve encounters effectively, while it also has been proven to potentially induce a collision in the hectic air traffic. Thus, new research considering the impact on safety is required to increase the airspace capacity based on a comprehensive analysis and accurate flight evaluation. In this paper, a causal encounter model is proposed to extend the TCAS logic considering the horizontal resolution manoeuvres, which could be used as the auxiliary supports when a potential collision is predicted in the vertical dimension. Based on the generated state space, the model developed in the graphical modelling and analysis software (GMAS), not only provides a better comprehension of the potential collision occurrences for risk assessment by representing the cause-effect relationship of each action, but also aids the pilots in the involved aircraft to make a cooperative and optimal option. Quantitative simulation results are conducted to validate the feasibility and effectiveness of the encounter model with horizontal resolution. The resulting collision scenarios are further investigated to illustrate that the risk rate of TCAS logic failures is expected to reduce by shortening the pilot's response delay, and the computational efficiency is competent in dealing with multi-threat scenarios.