A normal probability integral and some applications

The integral of a two-dimensional normal distribution over a wedge-shaped domain has many application in reliability analysis. A simple approximation suitable for many technical applications, and several more accurate representations by fitted polynomials and by tables are given. Application is illustrated for system reliability analysis; disaggregations of failure according to human error, random error or “act of God”; estimation of errors in the normal tail approximation; and fast probability integration of piecewise normal distributions.     

Particulate forms of radium and barium in uranium mine waste waters and receiving river waters

A method of selective dissolution was used for analysis of particulate forms of radium and barium in a system consisting of uranium mine waste waters purified by coprecipitation with barium sulphate and of adjacent river waters. Four particulate forms of both the elements were distinguished: “loosely bound”, “acid soluble”, Ba(Ra)SO₄ and “in crystalline detritus”. It was found that the distribution of radium and barium between dissolved and particulate forms in waste waters depended on the time interval elapsing between the sampling and membrane filtration of the waters. No such dependence occurred in river water. The main particulate form of radium and barium in the system was Ba(Ra)SO₄. River water upstream of the mine water discharge contained radium mainly in “acid soluble” form or “in crystalline detritus” and barium as BaSO₄ or “crystalline detritus”. In unpurified mine effluents, a large part of radium and barium was present as “crystalline detritus”. Abundance of the “loosely bound” form was very low in all the samples analyzed. The bond of radium in bottom sediments was approximately the same as that in the solids suspended in waste waters. Suitability and accuracy of the selective dissolution method for analysis of surface and waste waters has been demonstrated by the analysis of the results and by radiotracer experiments.     

Aquatic contamination and ecological risk. An attempt to a conceptual framework

The aim of this paper has been to introduce a conceptual model concerning the causal relationships determining the “road between dose and response” of toxic substances in aquatic environments. The paper is focused on metals and utilizes mercury as a type element. The approach puts special emphasis on the environmental factors regulating the potential effects of contaminants and stresses the importance of sedimentology in ecotoxicology. The approach discusses concepts like ecological effect, dose and sensitivity. A potential ecological risk index to be used in practical environmental control programs must also be based upon tested and comparatively inexpensive standard methods. Such an index should account for “biological contact area”, “biological contact time” and “additive effects”. A fundamental concept in this approach is the residual term, which describes the fact that it is impossible in ecological contexts to reach a complete understanding.     

Evaluating intelligent buildings according to level of service systems integration

The intelligent building is supposed to provide the environment and means for an optimal utilization of the building, according to its designation. This extended function of a building can be achieved only by means of an extensive use of building service systems, such as HVAC; electric power; communication; safety and security; transportation; sanitation, etc. Building intelligence is not related to the sophistication of service systems in a building, but rather to the integration among the various service systems, and between the systems and the building structure. Systems' integration can be accomplished through teamwork planning of the building, starting at the initial design stages of the building. This paper examines some existing buildings claimed to be “intelligent”, according to their level of systems' integration.     

Bayesian frameworks for integrating QRA and SRA methods

Lately there has been an increasing interest in using Structural Reliability Analysis (SRA) methods in Quantitative Risk Analysis (QRA). The Bayesian approach seems to be the most applied framework for the integrated analyses. It is, however, not clear what the Bayesian approach really means. There exist alternative Bayesian approaches, and the integration of SRA methods and QRA is very much dependent on what is the basis. The purpose of this paper is to contribute to a clarification and give some guidance with respect to the choice of approach. The starting point is our experience from the petroleum sector, but the discussion is to large extent general. We conclude that the most suitable framework for integrating SRA methods in QRA is to adopt the “fully Bayesian approach” with focus on observable quantities and use of subjective probabilities.     

Soil Stabilization with Cement Grouts

“New” advertizable injection methods of enhancing the bearing capacity of soils by the “ geomass” and “geocomposite” methods with use of high-pressure injection of cement and cement-sand grouts, as well as stabilization of sandy soils with “microdur” cement are analyzed. Significant drawbacks of the “geomass-geocomposite” methods, which do not permit prediction and operational monitoring of results of changes in the physico-mechanical properties of the soils in a mass, are noted.__________Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 2, pp. 24–28, March–April, 2005.     

Bridge design with reserve and residual reliability constraints

System reliability is evolving as an important design method for selecting components and topology. It should be used to investigate the original intact structure behavior as well as providing sufficient reserve capacity under likely accident and damage scenarios. Highway bridges are an area of special concern since effort to optimize the cost of construction may not provide adequate redundant capacity. The paper describes an example in which a typical girder bridge structure is optimized (both size and girder spacing) to achieve target system performance. System reliability constraints are imposed on the behavior of the intact structure under highway loads. Also, residual system reliability constraints are imposed to control safety under specified accident scenarios corresponding to damage and “lost” members due to corrosion, fatigue, fire or accidental collisions. An optimal design framework for controlling safety under all these life cycle situations is thus provided.     

The capital budgeting evaluation practices (2004) of building contractors in Hong Kong

This paper reports the investigation results of capital budgeting evaluation practices of Hong Kong building contractors. The survey aims to identify the popularity of various techniques for capital budgeting evaluation and to measure the changes of the practices longitudinally by comparing the results of the current study (2004) with those of the similar surveys conducted in 1994 and 1999. The current survey results revealed that the “formal financial evaluation” was the most popular technique for capital budget evaluation. The “payback period” was the mostly used investment appraisal technique. For risk appraisal techniques, “shortening payback period” occupied the first position. The “planning programming” remained as the most popular management science technique. Moreover, a comparison of the practices of large contracting firms was carried out to view the changes over the last 10 years. The results showed that the practice of capital budget evaluation was emphasized. The popularity of employing investment appraisal and risk analysis techniques was dropping. In addition, the capital budgeting evaluation techniques examined were fitted into a discriminant function analysis (DFA), which allowed contracting firms to be classified in accordance with their predominant characteristics in the practices. The classification result was 89.1% of all cases were correctly classified.     

A continuum of organizations formed to carry out projects: Temporary and stationary organization forms

Projects are carried out by temporary organizations. These organizations can function independently or in cooperation with stationary organizations. To enable efficient project and program management, these differences in organization structure have to be considered. This paper therefore contrasts organizations formed to carry out activities at project sites based on forms of employment, work processes and resource networks used. Findings indicate that temporary organizations that are dominated by stationary “parent” organizations often rely on its abilities to secure access to crucial resources and to identify suitable work processes. “Pure” or virtually “pure” temporary organizations instead rely on their employees’ skills and contacts to develop suitable routines and gain access to resources.     

Urban planning and a Europe transformed: The landscape politics of scale in Valencia

This paper explores how urban planning in a European, regional capital—Valencia—is shaped by economic globalization and political restructuring. Employing the vocabulary and concepts of the emerging literature on scale, this paper examines how planning efforts—like Valencia’s massive new redevelopment project, the City of the Arts and Sciences—are driven by the wider “re-scaling” or “re-territorialization” of the European political economy. This is a case study that moves beyond abstract theorizations about scale to the complex details of planning strategy in a regional context. More, it argues that an analytical shift from abstract theory to the empirical detail of a European city reveals two basic points. First, the re-scaling of Europe is more contested locally than this literature would suggest, negotiated politically as planners attempt to “re-scale” urban spaces. Second, the planned re-scaling of the city is about more than just space, but is also about the cultural landscape. Planned efforts to transform cities like Valencia in the image of global capitalism or European integration must navigate these complex, cultural politics. Theories of European re-scaling must account for the cultural politics in which planning is embedded, since planners must surely do so.     

Preferences for and attitudes towards street flowers and trees in Sapporo, Japan

The benefits of street vegetation, in particular the importance of trees, for urban dwellers have been given wide attention. There is, however, a lack of research on flowers as an element of street vegetation. This paper explores preferences for various street-planting models, particularly those with different compositions of flowers, with or without trees. Eighty-one residents of Sapporo evaluated 59 photomontage simulations and answered a questionnaire concerning their attitudes to street flowers. Results revealed trees to be the factor with the greatest influence on preference. Among possible elements for the space beneath trees from a choice including soil, grass, hedge and flowers, flowers were the most favoured. In particular, low and ordered compositions of brightly coloured flowers were the most preferred. Tall flowers were not found to be either attractive or appropriate for streetscapes in this case study. A factor analysis of the variables related to attitudes towards street flowers revealed the following five factors: “psychological benefits and aesthetic value”, “natural–environmental”, “practical concerns”, “effort to maintain” and “non-aesthetic”. The highest rated items were all related to the aesthetic and psychological benefits of street flowers. Flowers were the most preferred element beneath street trees and were seen as not only contributing to the aesthetic quality of a street but as also having a positive influence on psychological well-being.     

The green hydrogen paradigm shift: Energy generation for stations to vehicles

The change from a global economy dependent upon fossil fuels to renewable fuels for the hydrogen economy is occurring now. Not in 50–60 years, but the hydrogen economy exists today. This is a “paradigm shift” of such significance and so dramatic as to underlie the making of the Third Industrial Revolution. And more importantly, the Third Industrial Revolution includes three “pillars”: distributed as on-site renewable energy generation, “green” hydrogen and advanced storage devices. Each of these pillars is not an adjustment or economic cycle or business bubble. Indeed, the hydrogen economy is global with the European Union and the nation-state of California taking the lead toward sustainable energy infrastructures.This paper addresses that paradigm shift, but also the immediate economic and business development for any region or nation-state. More significantly, when the production of hydrogen is derived from renewable energy resources, not only are there societal benefits (no pollution and atmospheric impact), but also sustainable economic development and job growth. Some of the immediate evidence can be seen in California where “civic markets” are indeed working, but also with the combination of infrastructures into hybrid systems. Herein the combination of hydrogen for stationary power with transportation fuel needs is expediting the paradigm change into sustainable economic feasibility today, not in 50 years or the next century.     

Resilient cities: meaning, models, and metaphor for integrating the ecological, socio-economic, and planning realms

Urban designers, ecologists, and social scientists have called for closer links among their disciplines. We examine a promising new tool for promoting this linkage—the metaphor of “cities of resilience.” To put this tool to best use, we indicate how metaphor fits with other conceptual tools in science. We then present the two opposing definitions of resilience from ecology, and give reasons why one is more appropriate for linking with design. Additional specific tools and insights that are emerging from, or being increasingly used in, ecology can further support the linkage with urban design. These include recognizing the role of spatial heterogeneity in both ecological and social functioning of urban areas, the integrating power of watersheds, social and ecological patch dynamics of cities, the utility of spatial mosaic models to capture function, the use of an integrated “human ecosystem” modeling framework, and the consequent perspective of metropolitan areas as integrated ecological-social systems. Three additional tools are related to the adaptability of people and human institutions. First is the recognition of a “learning loop” in metropolitan ecosystems in which people respond to and affect ecological change, the use of urban design as experiments whose ecological and social outcomes can be measured, and finally the potency of a dialog between professionals and citizens, communities, and institutions, to support both research and design. The metaphor of resilience, and its technical specifications, draw these diverse strands for linking ecology and planning together.     

Adaptive hybrid conditional expectation approaches for reliability estimation

Conditional expectation is a simulation procedure that can be used to estimate the reliability of structures. It involves selecting an important random variable, using Monte Carlo simulation to generate sets of sample outcomes of the remaining “unimportant” random variables, estimating the conditional failure probability for each set of sample outcomes and using the average conditional failure probability as the estimate of the failure probability. This direct conditional expectation approach can be extremely effective, but only if the selected important random variable is much more important than the combined effect of the remaining random variables.In this paper, the concept of using importance sampling to generate the unimportant random variables is introduced. With a good sampling density, this greatly improves the efficiency for cases in which the selected important random variable does not dominate. To select such a density, however, one needs informations about the important regions of the failure domain. Typically, such information is not available a priori, and the direct application of this concept is limited.This concept can, however, be used in an adaptive format and two such adaptive hybrid conditional expectation approaches are developed in this paper. They are based on the idea that, as one generates sample outcomes and calculates the conditional failure probabilities at these outcomes, the knowledge of the failure domain increases. If one keeps modifying the importance sampling density to reflect this increasing state of knowledge, one can develop a good sampling density and simultaneously estimate the failure probability efficiently.Examples are used to demonstrate the efficacy of these approches and study the influence of factors like failure probability level and relative importance of random variables. Also discussed are issues such as the efficiency of the new methods (compared to FORM) and the applications to problems involving unions and intersections.     

Etude de l'evolution de la qualite des eaux de riviere

In France, the creation of a “Ministère de l'Environnement et du Cadre de Vie” and “Agences Financieres de Bassin” has made it possible to obtain information on the water quality of rivers and on the measures necessary to improve water quality. Particularly in the Adour-Garonne Basin, much information is now available. The methodology needed to draw conclusions concerning the quality of the rivers and to show the effectiveness of control measures has been developed.This method has been tested in two catchments (Fig. 1): L'Adour (15,000 km²) and La Dordogne (24,000 km²). The steps that were necessary before this method could be used were: critical assessment of the available data; identification and measurements of pollution sources. This called for the collection of information, annual statistics for each sampling station and information concerning the value and importance of measured parameters.Detailed information is available from 1971 and 1976 and this is shown by maps and graphical representations of the variations in the value of different parameters (Fig. 2).Statistical analysis has also been carried out on the information available for the period 1971–1976.Two methods were used: analysis of the principal components, the method most used being shown by Figs 3 and 4 and the “STATIS” method developed recently which treats the whole data “At 3 indices” (Fig. 5).Research has been carried out on the causal relations between the water quality and the sources of pollution.A simple graphical method is proposed to explain the effect of a strongly preponderant pollutant source. It allows easy visualisation of the change in the relationship between two series of variables (Fig. 8).In general cases of several sources of pollution a simplified method using BOD exclusively has been developed. It consists in comparing the values measured in the river and the estimates obtained from inflows of various sources and those from upstream basins (Fig. 9).The application of this method has made it possible to distinguish local or general tendencies in reference to the intervention realised by the “Agence Financiere de Bassin”.Attention has been given to the variations obtained between laboratories and research information and the necessity to extend application of the statistical method to parameters other than BOD₅.Comparable action is being taken for the whole basin of the Rhone (French). The information obtained for “L'Adour and La Dordogne” has led to a study not only of the concentration of pollutants but two types of flow, with flow measurements and concentration being taken into account in order to eliminate hydraulic effects.     

Growth of psychrophilic and mesophilic, aquatic bacterial isolates at the environmental temperature

The majority (80.4%) of the bacteria isolated from the sediment-water interface of Bethel Lake, a highly productive lake which experiences extremes of temperature due to season, when the in situ temperature was 9°C were mesophiles. The remaining 19.6% of the bacteria were facultative psychrophiles, but the absence of obligate psychrophiles was peculiar to this sampling. A number of the facultative psychrophiles were capable of growth at 37°C. Nine distinct mesophilic “working types” and 11 distinct psychrophilic “working types” were obvious according to the criteria of colony morphology and colour, cell morphology and arrangement, Gram reaction, gelatin liquefaction, starch hydrolysis, cellulose digestion, chitin decomposition, and Tween 80 hydrolysis. The psychrophilic isolates were more versatile than the mesophilic isolates with regard to utilization of the substrates. Comparison of the growth of the psychrophilic and mesophilic types at the in situ temperature at the time of sampling did not reveal a direct relationship between numerical predominance and growth rate at the environmental temperature.     

Performance of “ductless” personalized ventilation in conjunction with displacement ventilation: Impact of disturbances due to walking person(s)

The performance of the novel “ductless” personalized ventilation in conjunction with displacement ventilation (DV) was compared with the performance of DV alone under realistic conditions involving disturbances due to walking of one or two persons. An office room with two workstations was arranged in a full-scale test room. Two thermal manikins were used as sedentary occupants at the workstations. Two pollution sources, namely exhaled air by one of the manikins and passive pollution on the table in front of the same manikin were simulated. The performance of the ventilation systems was evaluated with regard to the quality of inhaled air and thermal comfort of the seated “occupants”. The walking person(s) caused mixing of the clean and cool air near the floor with the polluted and warmer air at higher levels and disturbed the displacement principle which resulted in a decrease of the inhaled air quality. The performance of the “ductless” PV under the tested conditions was better as opposed to DV alone. Thus in practice the “ductless” PV will be superior to DV alone as regards perceived quality of inhaled air. The location of a walking person was found to be important. Person(s) walking close to the displacement diffuser will cause greater disturbance.     

From Concentration to De-concentration — Migration Patterns in the Post-socialist City

The paper analyses the changing patterns of migration in the transition process from a “Socialist” into a “Capitalist” city against the background of “Modernization Theory”. Based on the example of Erfurt, a former district capital and now capital of the new federal state of Thuringia, an overview is given of basic population development trends before and after the unification of the two Germanys. A more detailed analysis of different urban areas (historic centre, city extensions of the industrial period, Socialist housing areas, new suburban housing areas) reveals a general turn-around of migration streams: Before 1990 the urban population showed a steady increase, while after reunification a dramatic loss could be observed. This decrease is caused both by emigration to areas in former West Germany, as well as by the beginning suburbanisation process. The latter is also fostered by the growing number of West – East migrants across the former internal German border. The findings are summarised in a model of the post-Socialist urban area.     

A Bayesian method for establishing fatigue design curves

From a reliability viewpoint, the simple conventional procedure for establishing design S−N curves from laboratory fatigue test data suffers from two important limitations. Firstly, the calculated fatigue reliability on the design curve only reflects the observed “physical” uncertainty associated with the fatigue process itself. “Statistical” uncertainties, connected with estimating the parameters of the fatigue model, are not considered. Secondly, it is not possible to account for fatigue run-outs (non-failures) in a rational manner.A new procedure, based on Bayesian statistical inference, is presented which is capable of handling both the above problems. Its use is illustrated via the analysis of some typical fatigue data sets and a number of general points arising from the results are discussed.     

The new three-dimensional subsidence influence function denoted by n–k–g

This study presents a three-dimensional development of the n–k–g influence function with the aim of predicting subsidence phenomena and characterizing the shape and dimensions of the corresponding trough. The parameters “n” and “k” characterize the ground and “g” is related to the gravity. This function depends on two physical concepts: the first is gravity, which characterizes the forces acting on the ground, and the second, the convergence of the roof and floor of the mine workings due to the stress state of the ground. Caving in of the roof generates direct subsidence, and the swelling of the floor, indirect subsidence, which allow us to establish the shape of the trough.The physical concepts introduced are fundamental in the mathematical implementation of the n–k–g influence function, allowing a more intuitive interpretation of the subsidence trough and notably facilitating the work of calibration, validation and sensitivity analysis. These concepts likewise allow the scope of application of influence functions to be extended to non-horizontal seams, also taking into account the quality of the rock mass and the presence of preferential sliding directions, in both the roof and the floor of the seam.In the development of this paper, we shall first see the physical concepts considered, to then present the three-dimensional implementation of our n–k–g influence function. We shall see the results obtained when calibrating the proposed numerical model with real data obtained from subsidence measurements in a coalmine in the Coal Basin of Asturias, situated in the North of Spain.