Schedule health assessment of construction projects

Several factors can contribute to the success of construction projects. A sound and good quality construction schedule is considered to be one of them. The quality of schedules has been a research topic only for a few efforts and amongst them construction-oriented research is even more rare. Methodical grounds for assessing schedule quality have been studied via literature study for the development of appropriate solutions to assess the quality of construction schedules. These findings combined with the experiences from practical implementations have resulted in the definition of a metric to measure schedule quality for construction projects. It includes 75 schedule requirements classified into 5 groups: general requirements, construction process, schedule mechanics, cost and resources and control process. This structure forms a core for the developed method to assess construction schedule quality termed as Schedule Health Assessment. The developed method has also the purpose of assisting project planners to produce and maintain good quality schedules starting from the project initiation until its completion, as via using the method to detect deficiencies of project schedules and other critical issues having importance with respect to schedule maintenance.     

Retrofit cost-effectiveness: Estonian apartment buildings

The economic viability and investment cost of the energy retrofit of apartment buildings are analysed through different energy efficiency levels. To analyse retrofit policy cost-optimal energy efficiency levels and investment costs, a baseline of measured actual energy usage of apartment buildings was created and then individual energy-saving measures and retrofit packages were composed. The cost-optimal level over a 20-year period for apartment building retrofit was a low-energy-building energy performance level, with an investment cost of €150–170/m². Retrofit to low energy building level would be economically viable but the investment capability of apartment owner associations is found to be insufficient for the necessary investments to achieve low-energy-building energy performance. Therefore, it is necessary to determine what levels of financial support can encourage retrofit to occur. The analysis of the current retrofit shows that subsides will increase investment by apartment owner associations into energy efficiency improvements. The target group for energy efficiency retrofit subsidies should be apartment buildings that reach low energy building performance level or at least match the energy performance requirement for new buildings.     

New developments in hematopoietic stem cell expansion

In the present study we investigated the effects of various doses of gamma-irradiation, followed by induction of granulocytic differentiation with all-trans-retinoic acid (ATRA), on proliferative rate, differentiation capability and oxidative metabolism of leukaemic cells from two different myeloid leukaemia cell lines, HL-60 and PLB-985. Regarding the effects of such combined treatment on the proliferative capabilities of HL-60 and PLB-985 cell lines, we showed that their growth kinetics were similar after 2 Gy gamma-irradiation combined with ATRA. However, with doses >2 Gy, the behaviour of the cell lines differed largely. Indeed, HL-60 appeared to be more radiosensitive than PLB-985 regarding cell viability and proliferation. Besides, whatever dose of irradiation (2, 5 or 10 Gy) was applied, ATRA was still able to induce differentiation of HL-60 and PLB-985 into granulocytes that retained the capacity to produce superoxide anion. The results of these in vitro studies suggest that leukaemia cell lines retain their ability to respond to ATRA, a granulocytic-differentiating inducer following high doses of irradiation. This may have implications for the use of radiation therapy in combination with ATRA for the treatment of extramedullary infiltrations of myeloid leukaemias in humans.     

HMGI-C, a member of the high mobility group family of proteins, is expressed in hematopoietic stem cells and in leukemic cells

The human HMGI-C gene encoding a member of the high mobility group protein family normally is expressed only during embryonic/fetal development but in none of the adult tissues tested so far. Recently, the HMGI-C gene has attracted a lot of interest since its rearrangements seem to underlie the development of frequent benign mesenchymal tumors. We have therefore checked CD34 positive hematopoietic stem cells and their normal and malignant descendants for HMGI-C expression. CD34 positive stem cells from healthy donors and the leukemia samples tested were positive while all peripheral blood samples from healthy volunteers were negative. We have concluded that the expression of the HMGI-C gene in leukemia seems to be a secondary effect due to abnormal stem cell proliferation and might be a sensitive tumor marker for particular types of leukemia.     

Across-path DN gradient in Landsat TM imagery of Amazonian forests: A challenge for image interpretation and mosaicking

An analysis of tropical rain forest covering Amazonian lowlands has highlighted a systematic across-path, east–west radiometric gradient within Landsat TM imagery. Visual assessment of 45 and quantitative analysis of 20 Amazonian Landsat-4 and -5 TM scenes show that the gradient is band dependent and pronounced in visible light bands 1 to 3 but significant also in IR bands 4 to 7. The results show that the scan line location of a pixel explains a considerable amount of the DN variation of forests in the width of the entire scene (B1: 70%, B2: 52%, B3: 44%, B4: 34%, B5: 46%, B7: 39%). In digital numbers, the difference between east and west side of a scene may be small (9, 4, 3, 10, 9, 3, respectively) but these differences become significant if the images are to be mosaicked, or the data are used for mapping relatively subtle differences of natural forests. Apparently, the gradient is a result of at least three factors: 1) shadows caused by the undulating terrain, 2) anisotropic reflectance of the varying surfaces, and 3) atmospheric scattering. The phenomenon becomes more significant when the sun is high and the scanning line is close to solar azimuth direction—a condition more easily encountered in lower latitudes of the earth.     

Fast and Stable Polynomial Equation Solving and Its Application to Computer Vision

This paper presents several new results on techniques for solving systems of polynomial equations in computer vision. Gröbner basis techniques for equation solving have been applied successfully to several geometric computer vision problems. However, in many cases these methods are plagued by numerical problems. In this paper we derive a generalization of the Gröbner basis method for polynomial equation solving, which improves overall numerical stability. We show how the action matrix can be computed in the general setting of an arbitrary linear basis for ?[x]/I. In particular, two improvements on the stability of the computations are made by studying how the linear basis for ?[x]/I should be selected. The first of these strategies utilizes QR factorization with column pivoting and the second is based on singular value decomposition (SVD). Moreover, it is shown how to improve stability further by an adaptive scheme for truncation of the Gröbner basis. These new techniques are studied on some of the latest reported uses of Gröbner basis methods in computer vision and we demonstrate dramatically improved numerical stability making it possible to solve a larger class of problems than previously possible.     

The dynamics of IT boundary objects,information infrastructures,and organisational identities: the introduction of 3D modelling technologies into the architecture,engineering, and construction industry

In recent years, more companies engage in collaborative cross-organisational practices to achieve their business objectives. To cooperate effectively across boundaries requires organisations to overcome the tension between their distinct backgrounds and the need to create shared understandings with their partners for collaboration. This requires the creation of shared artefacts such as boundary objects. Whereas the past work on boundary objects has highlighted their role as translation devices, we examine them in relation to the information infrastructures within which they are embedded, and the identities of the organisations that use them. We propose a model that outlines the relationships among the three concepts and illustrate its dynamics by presenting two case studies that describe the introduction of three-dimensional modelling technologies into the architecture, engineering, and construction industry. Based on the case studies we suggest that boundary objects, in addition to facilitating cross-organisational communication, also help to form organisational identities. We further suggest the occurrence of a process whereby changes in boundary objects enable changes in information infrastructures and identities in one organisation. These changes, in turn, create the conditions for change in bordering organisations through shared boundary objects and boundary practices.     

The brave new world of design requirements

Despite its success over the last 30 years, the field of Requirements Engineering (RE) is still experiencing fundamental problems that indicate a need for a change of focus to better ground its research on issues underpinning current practices. We posit that these practices have changed significantly in recent years. To this end we explore changes in software system operational environments, targets, and the process of RE. Our explorations include a field study, as well as two workshops that brought together experts from academia and industry. We recognize that these changes influence the nature of central RE research questions. We identify four new principles that underlie contemporary requirements processes, namely: (1) intertwining of requirements with implementation and organizational contexts, (2) dynamic evolution of requirements, (3) emergence of architectures as a critical stabilizing force, and (4) need to recognize unprecedented levels of design complexity. We recommend a re-focus of RE research based on a review and analysis of these four principles, and identify several theoretical and practical implications that flow from this analysis.     

Action based model of information system

The paper discusses some weaknesses in recently suggested models for information system specification. An augmenting, formal model of an information system is composed basing on the view that an information system essentially has a mediating role in the organizational discourse. This view permits the application of the speech act theory, and recent results in the organization theory. These general theories are adapted for information systems yielding a formal interpretation. It does not focus on the technical specification but on the formal structure of social interaction through an information system.     

Reel-to-reel inline atmospheric plasma deposition of hydrophobic coatings

Plasma deposition equipment was developed and installed at a pilot extrusion coating line for reel-to-reel substrates. Hexamethyldisiloxane was used as a siloxane precursor for the atmospheric plasma deposition of siloxane coatings on substrates of three different categories: paper, polyethylene-coated paper, and textile materials (woven cotton fabric and polypropylene nonwoven). SEM, H₂O contact angle measurements, heat sealability, and water vapor barrier measurements were carried out to characterize the composition and surface structure of the samples. The potential of the method and the equipment was shown by the coatings, ranging to micrometer scale. With selected samples, hydrophobic coating was shown to form at speeds up to 100 m/min.