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A Galach & Z Kotulski

Risk assessment in disaster recovery strategies development

Abstract: The paper describes the model for selecting disaster recovery strategies for information system. The risk assessment covers the threats and vulnerabilities related to the problem of losing the availability of information processes in the particular information system model. The analysis takes under consideration the relationships between the components of information system in order to find the risk of availability lost propagation within the system. That is the basis for finding the candidate disaster recovery strategies, which have to fulfil these basic requirements. Such an approach allows sifting these ones, which are basically not suitable for the security requirements of the information system. The preliminary accepted strategies are to be analyzed regarding to the estimated cost of implementation and maintenance. The next phase covers the detailed analysis of confidentiality and integrity risks in the candidate strategies. The level of risk related to the confidentiality and integrity of information processed in the disaster situation using given strategy is to be estimated.

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Full text: content.pdf (232,912 bytes) (available to registered users only)

Series: w78:2005 (browse)
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Permission to reproduce these papers has been graciously provided by the Technische Universität Dresden.


Cooper G, Rezgui Y, Hayes P, Jackson M,

Notification and change propagation support in aconcurrent, multi-actor environment

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Full text: content.pdf (62,899 bytes) (available to registered users only)

Series: w78:1997 (browse)
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Engdahl S

Product identification systems for construction and facility management

Abstract: This paper presents a study of the concept of a common construction product identification system with a focus on the establishment of principles for its use within computer integrated construction and facility management processes. An analysis of current systems for product identification utilized within the Swedish sector of construction and facility management is presented in an addition with a discussion of the concept of object and class identification in information systems development. The study is a part of the industry doctorate research project ‘Product information in computer-integrated construction and facility management processes’, which aims at studying methods for handling product information and contribute to the development of computer based systems for product information management. A main hypothesis within this project is that an information platform enabling efficient integration of IT in handling construction product information is composed of an identification-, classification-, and an attribute system. These components should be mutually independent and implemented as sector wide standards. This study specifically deals with the first component, a common system for identification of construction products. During recent years an increasing amount of research has been dedicated to define methods to integrate and utilize information technology in handling the vast amount of information used, created and transferred within construction and facility management processes. In Sweden, the focus has been on classification systems and product models as central means for establishing a framework for information handling. A common system for product identification would in general facilitate handling of product information in computer integrated construction and facility management processes. Specific advantages would be to enable; - Dynamic invocation of distributed components (e.g. CORBA) representing the product via a link relation residing in a database connected to the Internet. - Direct product information retrieval in case of a present identifier on a product, catalogue page or advertisement. - Exactness in production follow-up, i.e. when consumed production resources are registered. A common system for product identification is considered to be relatively easy to define and implement in comparison with common standards for product classification, attributes and product models, since the latter ones are aspect dependent and involve numerous actors and divergent interests. The purpose of this study is to identify and analyze current systems for product identification used within the Swedish sector of construction and to demonstrate the role of such systems in IT based environments for handling construction product information. The study shows that separate actors within the building process so far have developed systems for product identification without support for the process as a whole. Among the systems analyzed is EAN-13 regarded as most suitable since it is international, non-sector specific, in correspondence with a barcode standard for automatic data capture and has the widest propagation. However, the EAN-13 system, like the other systems, lacks explicit norms that guarantee valid identification in a historical perspective especially required for product information management within facility management processes. EAN-13’s main disadvantage in the construction context is its total focus on trade items, thus its deficient handling of standard product units, which is the common view for actors outside the sector of trading. The conclusion implies that a common system for product identification with characteristics of being international, non-sector specific, without property or class referencing attributes and with explicit criteria regarding changes of identifiers as a result of property alteration would be most advantageous and that such system is a central component in an information platform with means for achieving efficient utilization of IT. None of the systems in current use is featured with all these characteristics.

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Full text: content.pdf (527,797 bytes) (available to registered users only)

Series: w78:2001 (browse)
Cluster: papers of the same cluster (result of machine made clusters)
Class: class.retrieve (0.020441) class.software-software (0.015031) class.bestPractise (0.012129)
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Permission to reproduce these documents have been graciously provided by CSIR Building and Construction Technology. The assistance of the editors, Mr. Gustav Coetzee and Mr. Frances Boshoff, is gratefully appreciated.


Howard R W

Reverse propagation of data for building management

Abstract: Lifetime data for the management of buildings is becoming more feasible and is now expected by more facilities managers. It should be possible to extract the data related to the building fabric and systems from that generated during design and construction. For this to be just what the users require and in the form they require it, depends upon their involvement at an early stage of a project. Reverse propagation can then enable their wishes to influence the data collected so that redundant data is not produced and does not cause confusion. New forms of procurement such as partnering, allow this early involvement; alternatively there must be standards to define the general form of management data. In Denmark the CIS-CAD system defines a simple format being tested on a series of projects. It extracts information needed for statutory authorities and management, and examples are given based on continuing experience of its use. The principles of reverse propagation are discussed and the trend in databases to allow input from both ends of the process. This will eventually allow a more precise and economic definition of the building model and core data needed for management.

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Full text: content.pdf (108,012 bytes) (available to registered users only)

Series: w78:1999 (browse)
Cluster: papers of the same cluster (result of machine made clusters)
Class: class.economic (0.014458) class.represent (0.010812) class.store (0.010747)
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Permission to reproduce these papers has been graciously provided by the Research Press of the National Research Council of Canada. The support of the editors, particularly Dr. Dana Vanier, is gratefully appreciated.


Mahmoud K M

Fracture behavior of welded steel bridge components

Abstract: This paper presents the investigation of fracture behavior of welded steel bridge components. The interaction between a macroscopic crack and continuously distributed microscopic damage in a power-law hardening material is studied by accounting for void accumulation in the vicinity of the crack-tip. The damage is assumed to be concentrated to a small circular zone centered at the crack-tip, where growth and coalescence of microvoids are invoked. A component, loaded in Mode-I under plane strain condition, is considered. The deformation theory of plasticity is employed to obtain the stress, strain and displacement fields ahead of the tip of the crack, where a damage variable, D, is introduced to describe the mechanical effect of distributed microscopic damage. Only isotropic damage is considered in this paper. For monotonic loading, the external applied stress for small-scale and large-scale yielding solutions is found to be proportional to a0 -1/ (n+1), where a0 is half the initial crack length and n is the strain-hardening exponent of the material. This reduces to Griffith's classical result for elastic material. For fatigue crack propagation under small-scale yielding, the effects of initial crack size, final crack size and the cyclic stress level on the service life of welded steel bridge components are assessed and found to be in good agreement with Paris power-law for fatigue crack growth.

Keywords: fracture behavior, bridge components, damage mechanics, microvoids, Mode-I, HRR singularity

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Full text: content.pdf (914,147 bytes) (available to registered users only)

Series: itaec:2003 (browse)
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Nassar K, Gunnarsson H G, Hilal L A

Parametric cost estimate of forming and placing of concrete using neural network

Abstract: Neural Networks have found their way to many applications in construction. One of the most common applications of neural networks in construction is to develop parametric estimates of construction projects or specific construction operations. Due to their versatility and ability to handle fuzziness, they have performed well in estimating specific construction operations for which cost is dependent on specific parameters. This paper presents a back-propagation Neural Network (NN) for the development of a parametric cost-estimating model of concrete forming and placement using a commercial forming system (Steel-Ply ). The main objective is to develop a neural network cost-estimation model and verify its accuracy using actual data. Actual project data, from a local contractor in western Illinois, was used to develop the NN model. The model was developed and optimized on a spreadsheet format. Parameters considered include the season of the operation, the wall thickness and height, the method of placement, and the shape index of the structure. The same data used to develop the NN cost-estimating model is used to perform a linear regression analysis to predict the cost of forming concrete. Outputs of the developed NN model were compared with estimates obtained from multiple linear regression models. The results indicate that the back-propagation NN model can be used satisfactorily to estimate the forming and placing of concrete. Furthermore, practitioners as well as students can use the developed NN model to learn about mechanism of neural networks.

Keywords: cost, estimating, parametric estimating, Neural Networks, construction, concrete forming, spreadsheet modeling, linear regression

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Series: itaec:2003 (browse)
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T. Celik, Y. Baalousha & F. Ibisevic

Developing a forecasting model for the prediction of inflation rates for use in life cycle cost analysis

Abstract: Life cycle cost (LCC) is a technique that satisfies the requirements of owners for adequate analysis of total costs. Inflation rate may be considered as one of the main parameters that may have an effect on a LCC analysis of a project. Therefore it is necessary during the life cycle cost analysis to carry out a detailed analysis and predict inflation rates for the future.This paper outlines the development of an artificial neural network model for forecasting the inflation rates for the project period. The artificial neural network back propagation algorithm is implemented by using Mat lab Package. The model trained by 25 inflation index values and tested with 25 inflation index values, by comparing the two sets, the error rates was found as 0.022. LCC spreadsheet was developed in Microsoft Excel, taking into consideration all costs that may be in-curred during the project life and predicted inflation rate.

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Full text: content.pdf (164,180 bytes) (available to registered users only)

Series: w78:2009 (browse)
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Vladimir Bazjanac

Space Boundary Requirements for Modeling of Building Geometry for Energy and Other Performance Simulation

Abstract: CAD models of buildings represent architects’ views of buildings. Data definitions that represent a given building conform to the internal data structure of the CAD software that is used to define the building and typically include data which facilitate the representation of the building in CAD, but do not necessarily by themselves define anything about the building. CAD representations of buildings are based on detailed definitions of building geometry; those definitions thus contain significant amounts of information needed by CAD tools but not used by other types of tools – those tools need only rudimentary definitions of building geometry to operate.Building energy performance simulation tools, as well as many other types of simulation and analysis tools (like acoustics and fire propagation simulation tools) have their own internal data models of building geometry. Such internal data models represent views of building geometry typically used by the disciplines served by these simulation and analysis tools, and are usually much simpler than the geometry data models of CAD tools. Consequently, CAD building geometry representations must be “simplified” and “reduced” before they can be directly used by other (non-CAD) tools.Most simulation and analysis tools define building geometry as systems of surfaces (i.e. surfaces that delineate walls, slabs, roofs, columns, beams, windows and doors) which are all part of the definition of spaces identified in the model of the building. Such surfaces are called “space boundaries” and are the critical part of the building geometry definitions for non-CAD tools. This paper clarifies and systematizes what a “simplified” building geometry for building energy performance and similar simulation and analysis tools must contain, and should help prevent misunderstandings and misrepresentations often encountered in the AECOO industry today. It describes the five “levels” of space boundaries, why and how they are defined, and how they are used by simulation and analysis tools. The paper discusses the 55 test cases pertinent to semi-automated modeling of building geometry for energy performance simulation that were developed to test space boundaries defined and exported in IFC format by model based CAD tools. It also discusses the process and tools that check instances of IFC definitions of building geometry exported by CAD tools.

Keywords: space boundaries, building geometry, IFC, performance simulation, testing and verification

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Full text: content.pdf (916,247 bytes) (available to registered users only)

Series: w78:2010 (browse)
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