Application of CREAM human reliability model to cargo loading process of LPG tankers

The storage and handling processes of liquefied petroleum gas (LPG) constitutes a complex operational environment in the maritime mode of transportation. The LPG cargo is carried by specially designed ships called LPG tankers. The LPG cargo loading and discharging operations have always potential hazards. Thus, the crew on-board LPG tankers should be fully aware of operational risks during the cargo handling process, which includes various critical tasks such as drying, inerting, gassing-up, cooling, and reliquefaction. During these stages, human reliability (operation without failure) plays a crucial role in sustainable transportation of cargo. Human reliability analysis (HRA), related to various parameters such as the human factor, technology, and ergonomics, is always a critical consideration as regards maritime safety and environment. The main focus of the research is to systematically predict human error potentials for designated tasks and to determine the required safety control levels on-board LPG ships. The paper adopted CREAM (Cognitive reliability and error analysis method) basic and extended versions in order to assess human reliability along with the cargo loading process on-board LPG tanker ships. Specifically, the model is demonstrated with an operational case study. Consequently, the research provides should contribute to maritime safety at sea and prevention of human injury and loss of life on-board LPG ship.     

NaI（Tl）多道谱仪测量固体样品时实验数据准确性分析

通过对同一样品中的放射性核素含量进行多次等精度测量,对结果的可靠性进行分析和出现离散的数据进行数据舍弃检验。在放射性测量过程中除考虑统计误差外,同时也应考虑仪器的、人为的及偶然因素导致的系统误差,从而提高测量精度。     

基于信息加工模型的管制员差错分类与分析

在Wickens的人类信息加工模型的基础上,加入注意功能、情景意识、内部和外部操作成形因素,建立了管制员信息处理模型。按照该模型,空中交通管制人为差错可按照认知领域分为感知与警觉性差错、短时记忆差错、长时记忆差错、判断与计划差错、响应选择差错和响应执行差错;影响管制员操作的情境条件可分为外部操作成形因素和内部操作成形因素。对以往空管人为差错的分析表明,在信息加工层面分类的人为差错更宜于确定差错的心理致因。基于该理论模型的差错分类系统可以改进人为差错分析的有效性和一致性,从而提高差错管理的有效性。     

Unveiling the liaison between human capital,trade openness,and environmental sustainability for BRICS economies: Robust panel-data estimation

Global warming and greenhouse gas emissions pose severe threats to environmental sustainability. A sustainable environment is a prerequisite for long-term socioeconomic growth and human survival. Green technology is brought about by a country's economic and financial openness, and education provides knowledge to the public and labor, contributing to environmental sustainability. Thus, this research aims to unveil the liaison between human capital, trade openness, and environmental quality for Russia, Brazil, India, China, and South Africa (BRICS) countries from 1998 to 2018. Several econometric methods, including the Driscoll–Kraay standard errors and the Dumitrescu–Hurlin causality approaches, reveal long-run and causal relationships among the modelled indicators. The Driscoll–Kraay standard error results show that human capital is negatively related to carbon dioxide emissions (CO₂ emissions). Imposing high tariffs and excise duties, changing tax structures, discouraging the inflow of polluted commodities, and encouraging green trade can help BRICS combat high environmental pollution. The results show that a one-point increase in human capital in models 1 and 2 can reduce CO₂ emissions by 1.5279 and 0.1538 points, respectively. In contrast, a 1% growth in trade can lead to a rise in CO₂ emissions of 0.3731% and 0.2384%, respectively. Similarly, financial development and energy consumption result in high CO₂ emissions in the long run. Moreover, a feedback effect of the human capital index on CO₂ emissions is discovered. As a result of the findings, the government and responsible authorities should provide financial support and encourage investments in the region's energy-resourceful and sustainable green projects.     

基于VaR的我国煤炭行业金融安全影响因素分析

从金融科学、安全科学角度,提出煤炭行业金融安全的定义,认为煤炭企业融资和投资过程中的金融安全管理是我国能源安全的重要保证。可以从宏观经济状况、融资状况和投资条件3个方面分析影响煤炭行业金融安全的因素。采用金融安全管理中的VaR风险估价方法将煤炭行业金融安全影响指标进行定量化描述,运用Eviews软件构建误差修正模型分析各个影响指标与煤炭行业金融安全之间的长期、短期经济关系,明确二者之间的影响机制。CPI、资金成本率和借款率对煤炭行业金融安全的短期波动有影响;从长期来看,GDP、资金成本率和借款率指标与煤炭金融安全有着正相关关系,CPI、资产负债率和汇率与煤炭金融安全有着负相关关系。     

Inverse modeling to estimate LNAPL plume release timing

Methodologies are presented for dating releases of light nonaqueous phase liquids (LNAPLs) using an inverse modeling approach with simple analytical models. Models for LNAPL plume migration are presented to predict LNAPL plume velocity in the unsaturated and saturated zones as a function of basic soil and fluid properties. A relative mobility factor is introduced for LNAPL movement at the water table that depends primarily on the van Genuchten n parameter (related to the breadth of the soil pore size distribution) and the magnitude of water table fluctuations. Estimated LNAPL plume velocities compare reasonably with more rigorous numerical models, which may be used in cases where data availability warrant the greater effort entailed.Two methods of estimating release timing and its uncertainty are investigated. A direct estimation method is described that determines travel time for a single observed travel distance based on estimated soil and fluid properties. Release date uncertainty may be determined using the first order (FO) or Monte Carlo (MC) methods. The second method for estimating release date involves nonlinear parameter estimation utilizing distance vs. time measurements and other data.A case study is presented for a field site where independent estimates of release timing were obtained from a numerical modeling analysis. Release timing estimates based on direct inversion of the analytical timing model agree well with the numerical analysis. Results for a second field site indicate that release date confidence limits estimated by the FO method, assuming log-normally distributed travel times, are close to values determined by the MC method, which makes no assumption regarding the form of the travel time probability distribution.Results for a hypothetical problem indicate that LNAPL velocity and travel time may be accurately estimated if sufficient data on travel distance vs. time are available. Incorporating prior information on relevant soil and fluid properties into the objective function reduces the uncertainty in release date if prior estimates are accurate. However, biased prior estimates may lead to over- or underestimation of release date uncertainty. Simultaneous estimation of soil and fluid properties and release date is possible if prior information is available to condition the parameter estimates.     

河流污染物通量估算方法分析(Ⅰ)——时段通量估算方法比较分析

通过对河流时段通量所采用的估算方法的误差比较分析,说明了实测河流断面时段通量中时间平均离散通量的贡献;并讨论了污染源的点源、非点源类型的差别对选择年通量估算方法的影响.通过实例探讨了河流长时间通量估算方法的使用范围,对估算方法的取舍原则进行了分析.      

APPLICATION OF GREY MODEL TOWARD RUNOFF FORECASTING1

ABSTRACT: A reliable forecasting model is essential in real‐time flood forecasting for reducing natural damage. Efforts to develop a real‐time forecasting model over the past two decades have been numerous. This work applies the Grey model to forecast rainfall and runoff owing to the model's relative ability to predict the future using a small amount of historical data. Such a model significantly differs from the stochastic and deterministic models developed previously. Ten historical storm events from two catchment areas in northern Taiwan are selected to calibrate and verify the model. Results in this study demonstrate that the proposed models can reasonably forecast runoff one to four hours ahead, if the Grey error prediction method is further used to update the output of the model.     

农业科技资源与农业经济发展关系实证

农业科技资源是实现农业发展方式转变和农业可持续发展的重要因素,发展现代农业也迫切需要将农业科技资源转化为现实生产力.为了分析农业科技资源与农业经济发展之间的动态关系,作者选取中国1990-2008年的统计数据,运用协整分析和格兰杰因果关系检验,考察了农业研究与开发机构科技活动经费支出、农业技术人员及农业机械总动力与农业经济增长的内在关系.实证结果表明:农业科技资源与农业经济发展之间存在协整关系,即长期稳定的均衡关系,但在短期内会偏离长期均衡.当偏离均衡时,长期对短期偏离均衡的调整力度为59.8%;存在从农业研究与开发机构科技活动经费支出、农业技术人员到农业经济发展的单向格兰杰因果关系,而反向关系得不到实证支持.但农业机械总动力与农业经济发展之间存在显著的双向格兰杰因果关系.因此,增加农业科技活动经费支出、培养农业技术人才、提高农业机械利用效率是促进农业经济发展的重要路径选择.     

对低浓度环境样品监测的质量控制

通过环境监测中对低浓度环境样品监测所经过的每个步骤可能引入的误差进行分析,找出产生误差的原因,并提出相应的减小或消除误差的措施。