Life quality time allocation index – an equilibrium economy consistent version of the current life quality index

The definition the life quality index for a country as originally suggested by Nathwani, Lind and Pandey is based on the gross domestic product (GDP), the expected life in good health at birth, and the fraction of life time the anonymous citizen of the country is occupied with money making work. The LQI is invented to serve as a mean to evaluate how much money that reasonably can be allocated to safety improving investments by simply requiring constancy of the LQI. By choosing that the importance of increments in the two first variables should be measured relative to the current values of the variables themselves, the relative increment of the LQI becomes defined as a convex combination of the two relative increments. The combination parameter is obtained by an optimality argument about the anonymous citizen’s distribution of his or her time between free time and work time. In the original definition this equilibrium economy principle is applied under the assumption that the GDP is directly proportional to the work time fraction. This direct proportionality has been relaxed by the first author in two earlier papers with an essential effect on the combination parameter. The present paper presents a further development casting the definition into dimensionless quantities that make the index get a pure unit of time and not the somewhat obscure unit as a power product of a money unit and a time unit. To avoid confusion, this new variant of the LQI is called the life quality time allocation index (LQTAI). Moreover, the Danish data from the period from 1948 to 2003 show good agreement with the relation between the productivity and the work time as obtained from the optimality argument. The data fitting leads to an estimate of the combination coefficient of c = 0.092 together with a reduction factor of r = 0.92 to be applied to the total life expectation at birth to obtain the expected life in good health. Among other infinitely many choices of (c, r) there are (0.085, 1.0) and (0.1, 0.85).     

The derivation and calibration of the life-quality index (LQI) from economic principles

The life-quality index (LQI) is a versatile tool to support the effective implementation of programs and practices for managing risk to life safety. The LQI allows a transparent and consistent basis for determination of the net benefit arising from projects, programs, standards and policies undertaken at some cost to improve safety or enhance the quality of life. The paper shows that the LQI model is in harmony with well-established principles of economics, utility theory and recent developments to quantify the progress of nations through indicators of human development. The initial calibration of the LQI was based on a simplifying assumption of a linear relation between the GDP and work time. In this paper, we modify the calibration using empirical data for GDP and work time and link the LQI model to well-established economic principles and theory of production. The proposed improvements to the model eliminate a systematic bias associated with estimation of societal willingness to pay for safety. In addition, it provides a rigorous basis for program evaluation to assist decision-makers in directing expenditures where they may most effective.     

Life quality index for the estimation of societal willingness-to-pay for safety

The engineering and management of human safety is an important societal objective that includes extensive efforts by governments, both legislative and administrative, to enhance the health and safety of the public. Although the achievement of safety goals depend primarily on individuals and organizations responsible for safety, much support is drawn from expertise in diverse scientific and engineering disciplines. The activities range from structural safety (dams, tunnels, bridges to tall buildings) to safe operation of hazardous industrial installations (energy generation facilities, LNG terminals, petrochemical plants) to transportation systems (airline, rail, car safety) to technologies designed to minimize adverse impacts on the environment. All these activities are crucially concerned with risk: with the likelihood and the probable effects of various measures on life and health. We have developed a unified rationale and a clear basis for effective strategic management of risk across diverse sectors. Safety is an important objective in society but it is not the only one. The allocation of society's resources devoted to safety must be continually appraised in light of competing needs, because there is a limit on the resources that can be expended to extend life. The paper presents the Life Quality Index (LQI) as a tool for the assessment of risk reduction initiatives that would support the public interest and enhance safety and quality of life. The paper provides an intuitive reformulation of the LQI as equivalent to a valid utility function that is consistent with the principles of rational decision analysis. The LQI is further refined to consider the issues of discounting of life years, competing background risks, and population age and mortality distribution. The LQI is applied to quantify the societal willingness-to-pay, which is an acceptable level of public expenditure in exchange for a reduction in the risk of death that results in improved life-quality.     

Decision modeling and acceptance criteria

This paper is partly tutorial by presenting well known classical decision theory in a slightly untraditional form, but it does also present thinking and results that have not been published in the engineering literature before. The paper introduces the mathematical modeling basis for rational formulation of decision criteria and public acceptance criteria connected to risk analysis of technical operations that may endanger human life and property. Public restrictions on the decisions concerning the design, construction and managing of the technical operation have in the past been imposed on the basis of the frequency and severity of experienced adverse events. No clear rationale to decide how restrictive the public should be in setting a boundary for allowable risk seems to have been applied. To clarify this problem, focus is on the difficulty of simultaneously having two decision makers, the owner that tries to optimize the net gain of the operation, and the public that has somewhat different preferences than the owner, but also strong interests in the success of the owner. The principles of rational decision are needed for appreciation of the problem. Recognizing that there is an insurance compensation value of a human life and a public money equivalent of a human life, where the last value usually is considerably larger than the first value, it is possible from the decision analysis to determine an upper limit that the public should impose on the ratio of the owner's expected loss rate to the expected gain rate. The public money equivalent of a human life is assessed by use of a recently in (Nathwani JS, Lind NC, Pandey MD. Affordable safety by choice: the life quality method. Waterloo, Ontario, Canada: Institute for risk Research, University of Waterloo, 1997) suggested Life Quality Index (LQI) that combines wealth in terms of Gross Domestic Product per person, life expectancy at birth, and yearly work time into a single number. The philosophy behind the published evaluations is that the prevention of a loss of a life is counteracted by a cost such that the LQI remains unchanged (Skjong R, Ronold K. Societal indicators and risk acceptance. In: 17th International Conference on Offshore Mechanics and Arctic Engineering, number OMAE98-1488. ASME; 1998; Rackwitz R. Optimization and risk acceptability based on the Life Quality Index. Structural Safety 2002;24:297–331.).     

基于LQI的隧道工程人员安全风险控制决策模型

在社会指数LQI理论的基础上分析得到最优安全成本ICAF,针对我国隧道工程特点提出隧道工程安全风险增强系数,依据ALARP原则建立了基于LQI的隧道工程人员安全风险控制决策模型,并以英国Jubilee线工程为例阐述了基于该模型的隧道工程人员安全风险控制决策流程.     

Model of observed stochastic balance between work and free time supporting the LQTAI definition

A balance differential equation between free time and money-producing work time on the national economy level is formulated in a previous paper in terms of two dimensionless quantities, the fraction of work time and the total productivity factor defined as the ratio of the Gross Domestic Product to the total salary paid in return for work. Among the solutions there is one relation that compares surprisingly well with the relevant sequences of Danish data spanning from 1948 to 2003, and also with similar data from several other countries except for slightly different model parameter values. Statistical analysis reveals a data structure that allows the formulation of a simple stochastic model for the development of the data sequences with the year. Simulations with the stochastic model show sample curve behavior of the same fluctuating appearance as the factual data. This indicates that there are no other significant systematically balance influencing parameters on the macro economical level than those considered in the definition in the previous paper of the Life Quality Time Allocation Index.     

A comprehensive model for streamlining low-energy building design

Building designers are often limited in their ability to reduce the environmental impact of buildings, due to a lack of information on the environmental performance of building components as well as inconsistencies in the way in which this information is derived. Whilst numerous tools exist to help facilitate the low-energy building design process, these typically require large investments of time and money that are often beyond those available within any particular project. This paper describes an approach for streamlining the design process to reduce building life cycle energy consumption. Building assemblies are ranked based on an assessment of the life cycle energy requirements associated with their use within a building. This facilitates early stage assessment, negating the need for a resolved design before the relative energy requirements of alternate design solutions are known. Previous work assessed the initial and recurring embodied energy as well as the operational energy requirements for heating and cooling associated with the use of a range of building assemblies, using a simplified house model. This paper presents a sensitivity analysis of variations to the floor area, shape and orientation of this model, to test the reliability and applicability of the ranking approach across a broad range of circumstances. It was found that these variations did not influence the ranked order of the assemblies in terms of their life cycle energy requirements. Thus, the ranking of assemblies appears to provide an appropriate approach for streamlining the selection of construction elements during the building design process.     

Stability Chart for Zero Tensile Strength Hoek-Brown Materials—The Variational Solution and its Engineering Implications

Most conventional slope stability calculations are based on the linear Mohr-Coulomb failure criterion. A substantial amount of experimental evidence suggests however that failure criterion of most soils is not linear particularly in the range of small normal stresses. Particulate media like soils usually have very small tensile strength; and the present work focuses attention on zero tensile strength materials obeying a limiting form of the non-linear Hoek and Brown empirical strength criterion. Previous investigations of the effect of strength function non-linearity on results of slope stability calculations were based on limiting equilibrium procedures that include various approximations and static assumptions. The present study presents complete results (safety factors and failure modes) of a rigorous variational limiting equilibrium analysis which does not include kinematical or static assumptions. Linear and non-linear failure criteria depend on different strength parameters and significant comparison of the effect of strength function non-linearity on stability of slopes is possible only for a given state of experimental information (i.e. a given data set). By performing such a comparison it is shown that strength function non-linearity has very significant effect on the results of slope stability calculations for relatively steep and very gentle slope inclinations. In both of these inclination ranges the non-linear analysis results in conservative slope design compared with the conventional Mohr-Coulomb criterion. In the range of intermediate slope inclinations, analysis based on the Mohr-Coulomb criterion is acceptable, resulting in more conservative results than the present non-linear analysis.     

围岩稳定性评判方法适用范围探讨

基于修正芬纳公式建立了围岩稳定性评判新方法,该方法基于轴对称模型建立径向位移解析表达式。轴对称的基本假定就是圆形洞室,静水压力和均匀初始应力场,各向同性和均匀围岩条件。通过系统分析轴对称假定条件的偏差范围对围岩稳定性判断方法的适用范围进行研究。基于经典的遵循莫尔-库仑屈服准则理想线弹塑性围岩中的洞室开挖问题,分析了各项异性和非均匀性的初始应力场及城门洞型洞室对洞壁变形的影响。研究结果对围岩稳定性评判方法的合理使用范围、精度与轴对称围岩条件提出了量化评价范围。     

基于标准计算平台的建筑生命周期碳评价

在相关研究基础上,该文提出建筑碳评价应当建立在通用计算平台上,以实现建筑各生命周期以及上下游产业碳评价标准的相互兼容,为全生命周期建筑碳评价提供更大的可能性和更好的操作性。通过对PAS2050的分析介绍,该文提出选择以广泛接受的PAS2050相关评价标准作为基准平台进行建筑碳评价。文中就评价边界与计算单位、不予计算的碳排放范围、碳储存、以及碳排放时间加权因子等方面对基于PAS2050的建筑碳评价方法及其特点进行了介绍。该文认为,PAS2050系列规范将陆续推出,其中针对建筑碳评价的相关标准将会成为建筑碳评价的国际性标准,填补低碳建筑量化评价标准方面的空白。     

H/YBT-1型摇摆试验台支承设计

对 Ｈ／ ＹＢＴ－１型摇摆试验台是一大型模拟试验系统、可实现纵、横摆两个自由度的摆动运动。本文对其支承结构设计、润滑与密封的合理选择进行了论述。同时，根据该试验台的工作特点和具体工况，确定轴承寿命计算方法，并全面计算了轴承的运行寿命和磨损寿命。     

Life cycle inventory of buildings: A contribution analysis

A companion paper presented the life cycle inventory (LCI) calculation model for buildings as a whole, developed within a global methodology to optimise low energy buildings simultaneously for energy, environmental impact and costs without neglecting the boundary conditions for thermal comfort and indoor air quality. This paper presents the results of a contribution analysis of the life cycle inventory of four typical Belgian residential buildings. The analysis shows the relative small importance of the embodied energy of a building compared to the energy consumption during the usage phase. This conclusion is even more valid when comparing the embodied energy of energy saving measures with the energy savings they realise. In most studied cases, the extra embodied energy for energy saving measures is gained back by the savings in less than 2 years. Only extremely low energy buildings might have a total embodied energy higher than the energy use of the utilisation phase. However, the sum of both remains small and the energy savings realised with these dwellings are large, compared to the energy consumption of average dwellings.     

Using life cycle assessment to derive an environmental index for light-frame wood wall assemblies

Following a life cycle assessment (LCA) approach, this study aims at defining an appropriate performance index to consider environmental impact in the development of a multicriteria evaluation comparing factory-built wood-frame exterior walls. The investigation is applied to a case study comparing five wall assemblies for the exterior wall of a residential building in Quebec City (Canada). For the five alternatives, the life cycle inventory (LCI) provided by the ATHENA™ Environmental Impact Estimator software is aggregated using three different life cycle impact assessment (LCIA) methods: IMPACT 2002+, Eco-indicator 99 and TRACI. The relative impacts of assembly components and of the operation energy source on the environmental performance of the assemblies are investigated by comparing midpoint and endpoint indicators calculated with the three LCIA methods. The study concludes to the acceptability, in this specific context, of using the climate change indicator as an appropriate environmental index.     

海峡两岸结构抗震设计方法比较与探讨

国内抗震规范中所采用的符号及名称与台湾的抗震规范多有不同,但是其含义本质上是相同的,对二者的对比讨论将有助于更好地了解两规范的内容,并为将来的抗震规范修正工作打下基础。本文在几个假定的基础上,对比了台北和高雄两地抗震设计与国内抗震设计方法上的不同。     

Optimum insulation thickness of residential roof with respect to solar-air degree-hours in hot summer and cold winter zone of china

Thermal protection of building envelope is one of the most effective ways for building energy conservation. In this study, the determination of optimum insulation thickness for residential roof with different surface colors is studied based on life cycle cost analysis and solar-air degree-hours in four typical cities of hot summer and cold winter zone of China. Four insulation materials including expanded polystyrene, extruded polystyrene, foamed polyurethane and foamed polyvinyl chloride are analyzed. The solar-air degree-hours are calculated considering night time operation and 24-h operation of the cooling and heating equipments. Life cycle total costs (LCT), life cycle savings (LCS) and payback period resulting from the use of optimum insulation thickness are calculated. Depending on different cities, insulation materials and roof surface colors, optimum insulation thicknesses of a typical roof vary from 0.065 to 0.187 m and payback periods vary from 0.9 to 2.3 years for 24-h operation of cooling and heating equipments; optimum insulation thicknesses are between 0.051 and 0.149 m and the payback periods are between 1.1 and 2.8 years for night time operation. At last, the effects of present worth factor, thermal resistance and climate on the optimum thicknesses are studied which is very useful for practical use to estimate the optimum thickness of insulation material.     

RELIABILITY BASED OPTIMAL INSPECTION AND MAINTENANCE FOR PIPELINE UNDER CORROSION

Nondestructive inspection tools used for pipeline inspection are uncertain in detecting corrosion pits and in sizing detected defects. Probability-based optimal inspection schedule analysis must taken these uncertainties into account. In this paper, the probability of time to failure is formulated as integral equations with domain of integration expressed as unions and intersections of domains of failure, defect detection, defect nondetection and maintenance criterion. The rate of defect detection as a function of defect size and the maintenance criterion are used as filters to eliminate the defects that are not fit for service in an expected remaining service life after inspection. Simulation procedure is given to estimate the probability distribution of time to failure by using the integral equations. To facilitate the probabilistic analysis, a standard uniformly distributed variate is introduce and used in defining the domain of detected defect and the domain of nondetected defect. The advantages of using the proposed simulation procedure are discussed. Optimal inspection schedules are selected based on the minimum value of the maximum probability of time to failure before inspections and before the time at the end of service life. Effect of inspection quality and maintenance criterion on probability of time to failure and on selecting optimal inspection schedule is presented through an illustrative application study.     

3D mode discrete element method with the elastoplastic model

The three-dimensional mode-deformable discrete element method (3MDEM) is an extended distinct element approach under the assumptions of small strain, finite displacement, and finite rotation of blocks. The deformation of blocks is expressed by the combination of the deformation modes in 3MDEM. In this paper, the elastoplastic constitutive relationship of blocks is implemented on the 3MDEM platform to simulate the integrated process from elasticity to plasticity and finally to fracture. To overcome the shortcomings of the conventional criterion for contact fracturing, a new criterion based on plastic strain is introduced. This approach is verified by two numerical examples. Finally, a cantilever beam is simulated as a comprehensive case study, which went through elastic, elastoplastic, and discontinuous fracture stages.     

Transient heat conduction in multi-layer walls: An efficient strategy for Laplace's method

Enhancing load calculation tools into building simulation programs requires an in-depth revision and fine tuning of the load calculation assumptions prior to the addition of the HVAC system modelling routines. It is of special interest the analysis of transient heat conduction through multi-layer walls where, in order to improve the coupling between the passive elements of the building and the HVAC systems, an improvement of the time resolution in the calculation becomes critical. Several methods have been historically used, although recently Laplace's method has been displaced by the State Space method.This paper proposes a new strategy for fine time resolution on the calculation of the response factors through Laplace's method considering a comparison with the performance of the State Space method when used to calculate conduction transfer functions. Our analysis shows that in order to achieve similar accuracy with both approaches, the State Space method requires significant additional computational time.     

信息与建筑环境养生

信息是物体系统结构的有序性及其能量的有序性或可用程度的量度。生命是高度有序的有机体,这种有序靠生命不断从外界吸收信息、物质、能量来维持。任何生命信息的缺失或过载都会损害人的健康。笔者根据人与物质、能量、信息的相互关系、研究了各种信息的特点以及信息和人作用的关系模型,最后笔者分析了信息与建筑环境的关系,并进一步阐述了由笔者提出的养生建筑环境的内涵。