Reducing risks in the investigation, design and construction of large concrete dams

An overview of the GeoSafe 2016 Symposium topic is provided using the example of large concrete dams for purposes of illustration.It is essential that the risks associated with large dams be evaluated rigorously and managed proactively at all stages of their lives so that the risk of failure remains As Low As Reasonably Practicable(ALARP).Rock engineering features of large concrete dams that require particular attention,assessment and monitoring during the investigation,design,construction,initial filling,inservice operation,and subsequent repair and upgrade stages of the lives of concrete dams are identified and illustrated by examples from recorded experiences.A number of major concrete dam failures,including that of the St.Francis dam,California,U.S.A.,in 1928,have led to significant developments in rock mechanics and rock engineering knowledge and techniques,as well as in dam design and review processes.More recent advances include a range of analytical,numerical modelling,probabilistic,reliability,failure mode and risk assessment approaches.

Regional Design Storm and Flood Modelling—Risk Implications in Ungauged Catchments

Most planned developments in a catchment for control of excess water using a culvert, bridge or dam spillway are located at a site in a stream where there are no discharge measurements. Even though, for gauged catchments a number of established flood frequency models and rainfall-runoff models do exist, for ungauged catchments mostly regional flood frequency and event-based rainfall-runoff models are used, which depend on regional parameters. In this paper, a regional approach for design floods is presented and risk implication for design of drainage structures assessed. A case study in light of the above has been considered at four ungauged sites in the Limpopo Drainage Basin in north-eastern Botswana.

Risk Assessment at the Design Phase of Construction Projects in Ghana

The study was carried out exclusively in Ghana to explore the approaches employed by consultants in risk assessment at the design phase of projects in Ghana. One hundred and fourteen (114) consultants were selected out of a population of one hundred and eighty six (186) from three main professional associations in Ghana made up of the Ghana Institute of Architects, Ghana Institution of Engineers and the Ghana Institution of Surveyors (Quantity Surveying Division) practicing in Ghana for the study. Both primary and secondary data were collected. A descriptive survey was also used to observe and describe the presence, frequency or absence of characteristics of a phenomenon as it naturally occurred, in order to gain additional information. A questionnaire was also designed to collect data from the architects, engineers and quantity surveyors. The data was analyzed using Statistical Package for the Social Scientists (SPSS) 17.0. Descriptive and inferential statistics, such as frequency tables, percentages and cross tabulations were used in the data analysis and summaries. Simple tests of associations were undertaken by using Chi square and Cramer’s V statistics to compare relationships between variables. Again, relative importance index was also used to analyze some of the data by computing to deduce their rankings. The relative importance index was used to analyze some of the data by computing to deduce their rankings. The research revealed that majority of consultants had an average knowledge of risk management. Based on the findings it was recommended that consultants undergo advanced training in risk assessment. It was therefore suggested that consultancy firms should develop a set of laid down procedures for consultants to use in risk assessment in order that the use of intuition employed by majority is lessened. The challenges observed in risk assessment and the remedial steps suggested curtailing the detrimental effects of risks would be of wide importance to many developing economies.

Identifying Risk at the Conceptual Product Design Phase: A Web-Based Software Solution and Its Evaluation

This paper introduces a web-based application that enables engineers or designers to identify risks during the conceptual phase of a product design. This software application was developed based on the Risk in Early Design (RED) method developed by Author, Stone, and Tumer. The RED method demonstrates that risks can be identified in the early phase of product design by relating recorded historical failure information to product functions. Based on the concept of RED theory and current industry needs, the goals of a web-based RED application were defined. These goals are the intended benefits or functionalities that the web-based RED application would provide. In addition, a multi-level evaluation framework was adopted to determine how well the application meets the needs of various organizations. As part of the evaluation, a questionnaire was developed and administered to a sample industrial and academic user group. The results of the evaluation indicate that the web-based RED software application meets many of the goals to help an organization in performing product risk analysis.

Simulation and uniform design-based automatic generation of risk scenarios

This paper presents a methodology for automatically generating risk scenarios for dynamic reliability applications in which some dynamic characteristics(e.g.,the order,timing and magnitude of events,the value of relevant process parameters and initial conditions) have a significant influence on the evolution of the system.The main idea of the methodology is:(i) making the system model "express itself" through simulation by having the model driven by an elaborated simulation engine;(ii) exploiting uniform design to pick out a small subset of representative design points from the space of relevant dynamic characteristics;(iii) for each selected design point,employing a depth-first systematic exploration strategy to cover all possible scenario branches at each branch point.A highly dynamic example adapted from the literature(a chemical batch reactor) is studied to test the effectiveness of the proposed methodology.

Design Tide Hydrograph with A Given Risk Threshold by A Copula-Based Multivariate Method

This paper describes the development of a T-year design tide hydrograph （DTH）. A core innovation is that the proposed technique uses the design risk threshold and copula-based conditional risk probability to analyze the optimal combination of high waters and low waters of the DTH. A brief description of the method is presented. The in situ semi-diurnal tide data at the coast of Jiangsu Province in China are analyzed. Marginal distributions for high waters and low waters of tides are examined. Furthermore, the joint distributions, condition risk probabilities and risk thresholds of high waters and low waters are presented. Results of the DTH from the proposed method are compared with those from the traditional same-multiple enlarging design approach. It is demonstrated that the proposed method is preferable.

大数据平台在市域治安风险防控中的设计与应用

通过对大数据技术在市域治安风险防控应用中的现状与不足进行剖析,深度挖掘市域治安风险源头和应对方法.探讨了适用于市域治安风险防范的大数据平台设计的要素基础与设计基础,对市域治安风险防控大数据平台进行结构设计、流程设计和功能设计,给出了矛盾纠纷风险防控、平安校园风险防控、重点关注人员时空轨迹分析等功能的实现方法,深度分析了由矛盾纠纷引起刑事案的内在因素(变量)及各因素的特征.为大数据在市域治安风险防控中的应用提供支撑.

Design,Manufacture and Maintenance of Pressure Equipment Based on Accidents Survey

Most of the important units of pressure equipment have been manufactured successfully in China related to the national key construction projects,such as 10 million tons/year oil refinery,million tons/year ethylene,large coal chemical,etc.However,some of them failed to operate shortly after their putting into service.Some suffered severe damage even during the previous period of manufacture and installation.In this paper,cases of accident survey and failure analysis are given for some typical pressure vessels.It is found that many accidents are related to insufficient consideration of the design and manufacture of the equipment.These accidents occur fundamentally because of the Chinese design standards codes for pressure equipment without risk or life concepts and the support from a database for potential risk existing in their dynamic service.Most designers and manufacturers are unable to make correct design,materials selection and manufacturing process all due to a lack of engineering experience.In order to avoid the repetition of the accidents and improve the safety,reliability and economy of pressure equipment,a platform is suggested for design,manufacture and maintenance of pressure equipment in China based on accidents survey.In other words,some effective precautionary measures are taken at the design and manufacture stage,and the design methodology has to be based on service life requirement and desirable risk level.At the service stage some reasonable inspection/monitoring approaches should be utilized to control risks and ensure the equipment operating safely until its desired lifespan.Finally,the basic scheme and some key technologies are briefly given for the platform construction.The concept of risk and life based design,manufacture and maintenance proposed herein has important significance for improving and perfecting the codes and standards for design,manufacture and maintenance of Chinese pressure-bearing equipment,enhancing the life and reliability of Chinese pressure-bearing equipment and promoting the development of in-service maintenance technology that combines safety and economy.

Impact of Improving Design Factor over 0.72 on the Safety and Reliability of Gas Pipelines and Feasibility Justification

Many years experience of the operation of high stress (>72% specified minimum yield strength, SMYS) gas pipelines and statistical analysis results of pipeline incidents showed that the operating pipelines at stress levels over 72% SMYS have not presented problems in USA and Canada, and design factor does not control incidents or the safety of pipelines. Enhancing pipeline safety management level is most important for decreasing incident rate. The application history of higher design factors in the U.S and Canada was reviewed. And the effect of higher factors to the critical flaw size, puncture resistance, change of reliability with time, risk level and the arrest toughness requirements of pipeline were analyzed here. The comparison of pipeline failure rates and risk levels between two design factors (0.72 and 0.8) has shown that a change in design factor from 0.72 to 0.8 would bring little effect on failure rates and risk levels. On the basis of the analysis result, the application feasibility of design factor of 0.8 in China was discussed and the related suggestions were proposed. When an operator wishes to apply design factor 0.8 to gas pipeline, the following process is recommended: stress level of line pipe hydro test should be up to 100% SMYS, reliability and risk assessment at the design feasibility or conceptual stage should be conducted, Charpy impact energy should meet the need of pipeline crack arrest; and establish and execute risk based integrity management plan. The technology of pipeline steel metallurgy, line pipe fabrication and pipeline construction, and line pipe quality control level in China achieved tremendous progresses, and line pipe product standards and property indexes have come up to international advanced level. Furthermore, pipeline safety management has improved greatly in China. Consequently, the research for the feasibility of application of design factor of 0.8 in China has fundamental basis.

Highway Planning and Design in the Qinghai–Tibet Plateau of China: A Cost–Safety Balance Perspective

Engineering designs for mountainous highways emphasize compliance checking to ensure safety. However, relying solely on compliance checking may lead designers to minimize costs at the expense of high risk indicators, since the overall risk level of the highway design is unknown to the designers. This paper describes a method for the simultaneous consideration of traffic safety risks and the associated cost burden related to the appropriate planning and design of a mountainous highway. The method can be carried out in four steps: First, the highway design is represented by a new parametric framework to extract the key design variables that affect not only the life-cycle cost but also the operational safety. Second, the relationship between the life-cycle cost and the operational safety risk factors is established in the cost-estimation functions. Third, a fault tree analysis (FTA) is introduced to identify the traffic risk factors from the design variables. The safety performance of the design solutions is also assessed by the generalized linear-regression model. Fourth, a theory of acceptable risk analysis is introduced to the traffic safety assessment, and a computing algorithm is proposed to solve for a cost-efficient optimal solution within the range of acceptable risk, in order to help decision-makers. This approach was applied and examined in the Sichuan–Tibet Highway engineering project, which is located in a complex area with a large elevation gradient and a wide range of mountains. The experimental results show that the proposed approach significantly improved both the safety and cost performance of the project in the study area.

不确定性视角下灾难防控的社会支付意愿评估研究

灾难政策设计需要权衡政策实施的成本与收益。社会支付意愿常用来评估灾难防控政策收益,其依赖于灾难损失的大小。灾难概率和规模是刻画灾难损失的两个重要变量。因此,本文基于灾难概率与规模提出了一种评估灾难防控的社会支付意愿理论框架。首先分析了灾难概率与期望规模对社会支付意愿的影响。结果发现,随着灾难概率的增大,社会支付意愿增大,但是减少单位灾难概率的社会支付意愿是下降的。随着灾难规模的增大,社会支付意愿也增大,且减少单位灾难规模的社会支付意愿是上升的。这意味着,社会支付意愿对灾难规模更敏感,特别当灾难规模较大时,为减少灾难规模社会愿意支付更多成本。进一步,考虑到灾难规模的厚尾不确定性,研究了灾难规模不确定性对社会支付意愿的影响。结果发现,随着灾难规模不确定性的增大,社会支付意愿也是增大的,但是减少单位灾难规模不确定性的社会支付意愿是下降的。这为灾难政策设计时如何权衡灾难概率与灾难规模提供了重要参考。

Towards Development of a Security Risk Assessment Model for Saudi Arabian Business Environment Based on the ISO/IEC 27005 ISRM Standard

Security risk assessment refers to the process of identifying, analyzing, and evaluating potential security risks for an organization. An organization’s assets, personnel, and operations are protected through it as part of a comprehensive security program. Various security assessments models have been published in the literature to protect the Saudi organization’s assets, personnel, and operations. However, these models are redundant and were developed for specific purposes. Hence, the comprehensive security risk assessment model used to safeguard Saudi organizations’ assets, personnel, and operations is still omitted. Using a design science methodology, the objective of this study is to develop a comprehensive security risk assessment model called CSRAM to assess security risks in Saudi Arabian organizations based on the International Organization for Standardization and the International Electrotechnical Commission/Information security risk management (ISO/IEC 27005 ISRM) standard. CSRAM is made up of six stages: threat identification, vulnerability assessment, risk analysis, risk evaluation, risk treatment, and monitoring and review of the risk. The stages have many activities and tasks that need to be accomplished at each stage. Based on the results of the validation of the completeness of the CSRAM, we can say that the CSRAM covers the whole ISO/IEC 27005 ISRM standard, and it is complete.

Design Capability Identify under Asymmetric Information

Under the condition of asymmetric information,the Spence 's Job Market Signaling Model is generally applied to inspect the design capability of a designer and his labor and efforts to be invested; however,since the"prior probability"and "posterior probability"have great uncertainties,the practical effect of this model is poor. On the basis of analyzing reverse selection questions,this paper provides a design capability screening model,which can make a designer automatically expose his hidden information so that necessary actions can be taken as required by the owner to realize risk sharing. A calculation example is finally given to demonstrate that the new model is helpful for an owner to select a designer with high professional level and to lead the designer to work hard,so it is of significant application value.

Application of quality by design in the current drug development

Quality by Test was the only way to guarantee quality of drug products before FDA launched current Good Manufacturing Practice. To clearly understand the manufacture processes, FDA generalized Quality by Design(QbD) in the field of pharmacy, which is based on the thorough understanding of how materials and process parameters affect the quality profile of final products. The application of QbD in drug formulation and process design is based on a good understanding of the sources of variability and the manufacture process. In this paper,the basic knowledge of QbD, the elements of QbD, steps and tools for QbD implementation in pharmaceutics field, including risk assessment, design of experiment, and process analytical technology(PAT), are introduced briefly. Moreover, the concrete applications of QbD in various pharmaceutical related unit operations are summarized and presented.

Risk Assessment of Aircraft’s Lateral Veer-off the Runway Surface during Landing

This article presents a methodology to determine the risk of aircrafts lateral runway excursion during landing via mathematical risk modeling. In addition, the methodology is demonstrated by means of detailed calculation of the lateral runway excursion risk value during the landing of the aircraft Airbus A310-200, in view of the maximum landing weight and the appropriate range of landing velocities according to the International Civil Aviation Organization specification. Obviously, the calculation demonstrates that the developed math solutions and equations presented herein are powerful tools to evaluate the risk of lateral runway excursion of the majority of aircrafts and for any airport. The method is also applicable to assess the residual level of risk at any specific airport and its deviation compared to the recommended safety level. Consequently, the presented mathematical solutions to determine the risk rate of lateral runway excursion during landing offers airports’ operational and safety management departments a viable tool so that appropriate measurements could be adopted. Finally, it is a methodology not only to assess the risk but also to determine the appropriate runway width.

不确定需求条件下考虑风险公平的危险品运输网络设计问题

危险品运输事故具有低概率、高后果的特征,降低事故风险是危险品运输研究的重点。危险品运输产生风险的同时伴随着风险在空间上的分布不均衡,此前研究关注总风险最小和风险公平的权衡,但较少考虑不确定需求下的运输网络。运输需求波动可能引起风险增加,为了解决不确定需求下考虑风险公平的危险品网络设计问题,构建了危险品多起点-终点(OD)对运输网络设计的双层混合整数规划模型,上层和下层问题分别为监管者选择关闭路段以及承运人选择最优路径,并通过自适应遗传算法和局部搜索算法进行求解。通过实例分析发现,不同需求情景特别是部分OD对中断时产生不同的最优网络设计方案,采用的遗传算法相比局部搜索算法运行时间稍长情况下获得的解更优。

Revisiting support optimization at the Driskos tunnel usinga quantitative risk approach

With the scale and cost of geotechnical engineering projects increasing rapidly over the past few decades,there is a clear need for the careful consideration of calculated risks in design.While risk is typically dealt with subjectively through the use of conservative design parameters,with the advent of reliability-based methods,this no longer needs to be the case.Instead,a quantitative risk approach can be considered that incorporates uncertainty in ground conditions directly into the design process to determine the variable ground response and support loads.This allows for the optimization of support on the basis of both worker safety and economic risk.This paper presents the application of such an approach to review the design of the initial lining system along a section of the Driskos twin tunnels as part of the Egnatia Odos highway in northern Greece.Along this section of tunnel,weak rock masses were encountered as well as high in situ stress conditions,which led to excessive deformations and failure of the as built temporary support.Monitoring data were used to validate the rock mass parameters selected in this area and a risk approach was used to determine,in hindsight,the most appropriate support category with respect to the cost of installation and expected cost of failure.Different construction sequences were also considered in the context of both convenience and risk cost.

Estimation of Attributable Risk from Clustered Binary Data: The Case of Cross-Sectional and Cohort Studies

Effect sizes are estimated from several study designs when the subjects are individually sampled. When the samples are the aggregate cluster of individuals, the within cluster correlation must be accounted for to construct correct confidence intervals, and to conduct valid statistical inference. The purpose of this article is to propose and evaluate statistical procedures for the estimation of the variance of the estimated attributable risk in parallel groups of clusters, and in a design dividing each of k clusters into two segments creating multiple sub-clusters. The estimated variance is the first order approximation and is obtained by the delta method. We apply the methodology and propose a Wald type confidence interval on the difference between two correlated attributable risks. We also construct a test on the hypothesis of equality of two correlated attributable risks. We evaluate the power of the proposed test via Monte-Carlo simulations.

中国碳排放权交易机制与实践:基于微观企业股权资本成本的视角

碳排放权交易市场作为企业减排增效的重要机制,引发了资本市场投资者对企业碳排放问题的关注,进而可能影响投资者对企业的风险评估与价值判断。手工整理中国各试点碳市场的控排企业名录发现:碳排放权交易机制显著提升了控排企业的权益资本成本,主要机制为投资者碳风险关注,但该市场机制存在明显的效应边界。进一步发现,当碳市场的初始配额实施部分竞价拍卖和非履约主体交易更为活跃,产品市场竞争程度更高和企业所在城市空气污染更为严重,以及企业非财务绩效表现更好时,碳排放权交易机制对企业权益资本成本的提升作用更为明显。研究结论有助于更为全面的评估我国碳市场建设的经济后果,为该低碳环保政策的持续推广提供理论依据与经验参考。

基于风险补偿效应的银行转股型永续债优化设计与定价

效应是衡量金融产品设计成败的重要依据。研究对永续债内蕴的风险补偿效应进行剖析与量化,并以风险补偿效应的控制为依据对转股条款进行优化设计:特别考虑了“部分转股”的情景,即在轻度财务困境时可实施部分转股,弥补了现有条款“一刀切”式的全部转股方式的弊端。进一步,给出了与所设计的转股条款相适宜的各利益方权益价值的结构化定价方法,并构建了可体现各利益方激励相容性的确定转股比例的约束优化模型,以充分体现发行方与投资者之间的“共建共享”特征。数值分析结果表明:适宜的转股条款设计可较好地控制风险补偿效应,既兼顾了永续债投资者的利益,又保护了发行银行股东的权益,且有利于提高发行银行的价值;所设计的转股条款在多种情景下均具有良好的可实施性,进而有望为永续债市场的良性发展提供有益的决策参考。