Problems in the extreme value analysis

Engineering design for structural safety is largely based on the statistics of natural hazards. These statistics are utilized by applying the theory of extremes, which predicts a cumulative distribution function of the extreme events. The parameters of this distribution are found by a fit to the historical extremes and the probabilities of potentially disastrous events are then calculated. It is pointed out here that this procedure often results in underestimation of the risk. This is because wrong probability plotting positions are widely used and because theoretical extreme value distributions are asymptotic only, so that in many cases they bring misleading information to the analysis. The means to avoid these problems in the extreme value analysis are outlined.     

A comparison of methods of extreme wind speed estimation

The paper presents a comparative assessment of methods for extreme value analysis of the US wind speed data using four different methods, namely Standard Gumbel, Modified Gumbel, Peaks-Over-Threshold (POT) and Method of Independent Storms (MIS). The analysis highlights the influence of methodological assumptions on the estimates of design wind speed corresponding to 50-year and 500-year return period. The results demonstrate that the MIS method leads to more stable quantile estimates than the POT method.     

Combination of the peaks-over-threshold and bootstrapping methods for extreme value prediction

The paper investigates the application of the peaks-over-threshold (POT) method in combination with the bootstrapping method for estimating extreme values, in particular, long return period characteristic values of environmental loads, e.g. wind loads, on the basis of observed data. Attention is focused on the effect different statistical estimators of the parameters inherent in the POT method have on the predicted characteristic values. The accuracy of the predicted long return period characteristic values provided by the different methods will be evaluated by application to synthetic data where the relevant characteristic values can be calculated. The bootstrapping method is advocated as a practical tool for estimating confidence intervals on the provided point estimates of the long return period values.     

The estimation of extreme quantiles of wind velocity using L-moments in the peaks-over-threshold approach

The paper evaluates the effectiveness of the method of L-moments for estimating parameters of the Pareto distribution model of peaks over a sufficiently high threshold, and compares its performance against a widely used method of de Haan (de Haan L. Extreme value statistics. In: Galambos J, Lechner J, Simin E, editor. Extreme value theory and applications, vol. 1. 1994. p. 93–122). Monte Carlo simulations and actual wind speed data collected at various stations in the United States have been utilized in this study. In the de Haan method, the first two moments of peaks of log-transformed data are used for the parameter estimation, whereas the L-moment method utilizes linear combinations of expectations of order statistics of peaks in the original data. Despite the procedural differences, the paper shows that the de Haan and two L-moments based estimates of the tail shape parameter are in fairly close agreement in simulated data as well as in the US wind speed data. Furthermore, higher order estimates of the shape parameter are obtained using the L-skewness of peaks data. Such estimates appear to provide a more stable upper bound, which can be useful in identifying meaningful values of design quantiles.     

浅谈价值管理在设计阶段的应用

简单介绍了建设工程项目价值管理及价值管理在设计阶段应用的要求，阐述了经验分析法、百分比法、ABC分析法等几种价值管理在设计阶段应用的方法，并对价值管理研究的应用——新建建筑中的价值进行了分析，以使设计全面体现建设工程项目的价值。     

方案设计在建筑设计中的价值与应用分析

随着我国经济的快速发展,建筑行业得到了极大的发展,逐渐成为我国经济组成中的支柱性产业。建筑方案的设计作为工程项目建设过程中的一个关键阶段,可以说其将会直接决定建筑工程的建设质量。     

野值诊断技术在大坝安全监测资料分析中的应用

大坝安全监测中常会出现偏离目标真值的野值。为有效检测观测数据质量和诊断野值,分析了野值产生的原因,在此基础上,研究了野值诊断的两种技术,即基于数理统计的残差分析和基于概率的随机模糊诊断技术。为验证方法的合理性,将其运用到燕山水库施工期监测资料的分析中,取得到了较好的结果。     

浅谈价值工程在设计方案优选中的应用

阐述了价值工程的含义、特点及一般工作程序,分析了建筑工程在设计阶段实施价值工程的意义,介绍了价值工程在新建项目设计方案优选中的应用实例,通过功能分析和功能评价以及方案评选,最终选定了最优方案。     

论价值管理在施工组织设计中的应用

介绍了价值管理的概念和价值管理的工作计划,论述了价值管理应用于施工组织设计的方案选择与优化,并结合工程实例探讨了价值管理在改扩建工程施工组织设计中的应用,以完善施工方案。     

Eastern Black Sea Region—A sample of modular design in the vernacular architecture

Rural settlements of Eastern Black Sea Region have an original architectural charateristics which are shaped by the climate and topographic conditions, local materials, and the social living style. But, this characteristic structure which is covering the vernacular houses, has been started to lose its specifications because of new buildings which are unconsidering the importance of local conditions and the architecture. The target of this study is to design model houses which are in accord with the vernacular architecture and climatic–topographic conditions, and will answer varying needs of the modern life. The realizations of these designs (with a prefabricated system which is easily carried, buildable on inclined topography, and simply installed) is important due to the regional conditions. Therefore, local texture will be saved, and a contemporary system will be adapted with the vernacular architecture.     

Monitoring of traffic action local effects in highway bridge deck slabs and the influence of measurement duration on extreme value estimates

In recent years, monitoring has offered a viable complement or even alternative to traditional analytical safety verification approaches. However, there still remains a lack of guidance for the use of monitored data in safety verification work. Limited resources often necessitate relatively short time frames for safety verification of problematic bridges. While the duration of monitoring is always an important consideration, it is rarely examined explicitly in terms of its influence on the predicted characteristic action effects. This work gives a novel approach for determining if a monitoring regime is sufficiently long to obtain a reliable extreme value estimate of the action effect. A case study of a highway bridge in Switzerland, with one year of continuous high-frequency measurements, is used to exemplify the approaches developed. The focus is on direct measurement of the traffic action effects in the bridge's deck slab reinforcement. A comprehensive statistical approach for determination of site-specific, element-specific extreme traffic action effects is presented.     

市政桥梁设计中的常见问题分析

桥梁设计是一项复杂性高且专业性强的工作,在设计时需要考虑多方面因素的影响。如果设计考虑不全面,将导致工程事故的发生。本文分析了我国市政桥梁设计时遇到的问题,并提出了相应的解决措施。     

Risk analysis of fire and evacuation events in the European railway transport network

According to international and national guidance (ISO 23932 [1] and the Fire Engineering Design Brief (FEDB)), the selection of the design fire scenario (DFS) is one of the major steps of fire safety engineering methodology. Once the DFS is chosen, its fire performance is evaluated through a fire analysis method in order to meet the fire safety objectives. Two DFS have been previously pre-selected by railway fire safety experts, during the Transfeu project, on the basis of their relevance and feedback. The relative fire risk analysis aims to test how valid and representative are the pre-selected DFS. Its method consists in finding a large number of possible fire sequences, from fire start to fire spread, in railway transportation. To identify these events succession, risk analysis tools such as events trees are used. The fire risk analysis result is a matrix of relative occurrence probabilities versus relative severities. The positions of the pre-selected DFS in the matrix are compared with the large number of fire scenarios. The method and results of the fire risk analysis are discussed in this paper. The main result is that the pre-selected DFS have a serious risk. These DFS are then used in a detailed quantitative assessment to predict the impact of fire on people in a train vehicle.     

Probabilistic assessment of the occupant load density in retail buildings

The occupant load density is a crucial parameter for the design of the means of egress in buildings. In retail buildings the occupant load density is highly influenced by the individual׳s choice and the necessity of a person to visit the store. This causes a high variability of the occupant load density in time. An accurate representation of this variability will provide a basis for enhancing fire safety design. In this paper, a probabilistic approach is used to describe the variability of the occupant load density over a year, based on long-term data of customer frequencies in combination with methods from the queuing theory the distribution of the occupant load density is derived for four different types of retail chains. It is shown that the type of a retail chain has a large influence on the distribution of the occupant load density and that the exceedance probability of current design values in different standards is very small. A method is proposed to derive design values for a performance based design on the basis of probabilistic models for the occupant load density. In addition, the developed probabilistic models describing the number of occupants in a store, allow the assessment of the occupant load density for other types of retail chains, even with incomplete data.     

Generating value across academic and professional design practice in the Internet of Things

ABSTRACT

This article accounts for how value in design research can be derived from knowledge exchange that occurs through the collaborative discourse of doing design. To demonstrate this point, the article details the arc and impact of a design research collaboration that extended over several years with design practitioners in the field of internet-connected devices. As a result of this ongoing collaborative work, a programmatic set of design ideals and intentions concerning how to construct a more transparent and ethical relationship with technology was shaped. We examine this sustained and transformative collaboration as a series of knowledge exchanges. Within each particular collaborative project, worldviews and knowledge are exchanged among design researchers and practitioners, enabling them to traverse ‘through practices’ of academic and professional design. To unpack these exchanges and how they built and fed into each other, the article examines how collaboration unfolded and produced value on two levels: first on the scale of the academics and practitioners directly involved in a project; and secondly on the scale of the larger international community of design practitioners concerned with Internet-connected devices, with whom we had shared our work.     

异形柱框架体系设计轴压比限值研究

从异形柱大、小偏心受压界限破坏条件出发,导出了钢筋混凝土异形柱轴压比限值的计算公式,分析了等刚度矩形截面柱轴压比限值存在的问题,并对异形柱轴压比设计值提出了建议。     

Assessing public projects' value for money: An empirical study of the usefulness of cost–benefit analyses in decision-making

Value for money, as measured by cost–benefit analyses (CBAs), is a crucial part of the business case for major public investment projects. However, the literature points to a range of challenges and weaknesses in CBAs that may cause their degree of usefulness in decision-making to be limited. The paper presents an empirical study of CBA practice in Norway, a country that has made considerable efforts to promote quality and accountability in CBAs of public projects. The research method is qualitative, based on a case study of 58 projects. The results indicate that the studied CBAs are largely of acceptable quality and heeded by decision-makers. Appraisal optimism seems to have been reduced by the introduction of external quality assurance of CBAs. However, there is need for a more consistent assessment of the non-monetized benefits, and distinguishing them from other decision perspectives such as the achievement of political goals. The paper offers a set of practical recommendations to increase CBA usefulness further.     

建筑结构设计中常见问题与解决措施分析

本文通过对建筑结构设计中的基本内容的探讨，对建筑在进行结构设计过程中的注意事项以及设计原则进行全方面具体的了解，从中找出在建筑结构设计中一些常见的问题，并针对这些问题提出一些相应的解决措施，希望能给相关人员一些有用的参考意见。     

大型汽车配件仓库的性能化防火设计

通过介绍性能化分析方法在某大型汽车零配件仓库防火设计的具体应用，分析了仓库存在的火灾危险性和危害性，以说明性能化防火设计方法解决此类大型汽车配件仓库防火安全设计的可行性。