Papers by Demos Angelides
Journal of Construction Research, 2005
The Build-Operate-Transfer (BOT) project development scheme allows realization of public works th... more The Build-Operate-Transfer (BOT) project development scheme allows realization of public works through private financing. This context is full of risks due to the great number of stakeholders from different disciplines involved. The contribution of this paper is the provision of a comprehensive list of the legal risks, associated with the BOT projects in their lifecycle. The framework of legal risks is discussed, the justification for each risk is presented and the content of each individual risk is elaborated. Furthermore, a risk classification ...
The construction industry, is mostly concerned with one – of – a – kind projects. This, naturally... more The construction industry, is mostly concerned with one – of – a – kind projects. This, naturally, creates difficulties for effective management control. Nevertheless, production costs need to be monitored and controlled, if the anticipated level of profit is to be realized. One of the most difficult things to control is the variance associated with materials. All supplies and materials add to the cost parameter of the project. Thus, greater attention to controlling the materials may pay significant dividends in the form of increased profit. This paper deals with monitoring and controlling the cost of materials during project execution. Reference and review will be made to the special characteristics of the construction industry as far as the cost parameters is concerned, during project development. Then, definition of materials and its cost elements and characteristics will be given. The proposed approach for controlling this cost category is based on a spreadsheet application. The component spreadsheets are identified and analyzed and their use is explained. Special consideration will be given to the description of the information content of each spreadsheet. These spreadsheets integrate the cost parameters with time and project advancement, so that the project manager could acquire an objective view of the cost deployment.
Journal of Fluids and Structures, 2012
Abstract In this paper, “wet” hydroelastic analysis is performed in order to investigate numerica... more Abstract In this paper, “wet” hydroelastic analysis is performed in order to investigate numerically the hydroelastic performance of a free, flexible, mat-shaped Floating Breakwater (FB) that consists of a grid of flexible floating modules connected flexibly in both horizontal directions. The investigation is conducted in the frequency domain under the action of oblique incident waves. A framework for this analysis is proposed, which includes three components: (a) a 3-D structural model for an initial “dry” eigenvalue analysis, (b) a 3-D hydrodynamic model for the hydroelastic analysis and (c) an iterative procedure, in terms of natural frequencies, for a “wet” eigenvalue analysis. The iterative procedure is applied in order to solve a nonlinear “wet” eigenvalue problem (resulting from the frequency dependency of the added mass) that enables the calculation of “wet” natural frequencies and “wet” mode shapes. The latter ones are used in the 3-D hydrodynamic model in order to perform the hydroelastic analysis. Results are compared with numerical and experimental results of other investigators. The investigation of the FB hydroelastic performance is implemented for different combinations of translational and rotational stiffness of the FB connectors. The effect of the connectors' stiffness on the generalized response, the effectiveness and the hydroelastic response of the FB are analyzed and demonstrated.
IASME …, 2005
Abstract: The European Union over the last decade has demonstrated a persistent will to promote c... more Abstract: The European Union over the last decade has demonstrated a persistent will to promote coastal zone management. A framework of Directives, demonstration programs, research and networks funding and efforts to motivate national resources has identified and promoted ...
Resilient systems present an inherent ability of recovering from a certain damage state reached d... more Resilient systems present an inherent ability of recovering from a certain damage state reached due to the application of a significant stress. The quantification of a system’s resilience is a difficult task to perform because of: a) the system’s complexity, b) the uncertain characteristics of the excitation force, c) the lack of specific elements to measure for an accurate assessment of a system’s resilience, and d) the lack of robust tools for quantifying a system’s resilience. Therefore, a decision maker requires both a methodology and the tools to decide for the most effective risk-response strategy. This paper presents such a methodology for a risk-based decision making for resilient systems. The proposed methodology involves the consideration of the following parameters: i) the variability of impact upon risk occurrence, ii) the available response strategies, and iii) the preference of the decision maker with regard to the criticality of the various impacts upon risk occurrenc...
World Academy of Science, Engineering and Technology, International Journal of Environmental, Chemical, Ecological, Geological and Geophysical Engineering, 2012
The Želazny Most tailing pond is one of the largest facilities worldwide for waste disposal from ... more The Želazny Most tailing pond is one of the largest facilities worldwide for waste disposal from the copper mines located in South-West Poland. A potential failure of the dam would allow more than 10 million cubic meters of contaminated slurry to flow to the valley, causing immense environmental problems to the surrounding area. Thus, the determination of the strength properties of the dam's soils and their variability is of utmost importance. An extensive site investigation consisting of more than 480 cone penetration tests (CPTs) with or without pore water pressure measurements were conducted within a period of 13 years to study the mechanical properties of the tailings body. The present work investigates the point variability of the soil strength parameters (effective friction angle ’) of the three soil layers consisting the dam's slope as well as the spatially-averaged variation of ’ over the slope’s slip surface; this information is based on the well-established relatio...
In this paper, 3D linear "Dry" and "Wet" Mode Superposition Approaches (DMSA ... more In this paper, 3D linear "Dry" and "Wet" Mode Superposition Approaches (DMSA and WMSA) for the frequency domain hydroelastic analysis of Floating Structures (FSs) are compared and assessed. The Present WMSA (PWMSA) enables the consideration of "wet" natural frequencies and "wet" mode shapes through the appropriate solution of a nonlinear (due to frequency dependency of the added mass) "wet" eigenvalue problem. The Present DMSA (PDMSA) is derived from PWMSA by excluding the effect of the surrounding fluid on the mode shapes'/natural frequencies' calculation. The two approaches are initially compared from a physical and a mathematical point of view and their main differences are highlighted. Although in PWMSA the "wet" mode shapes are expressed as a linear combination of the "dry" ones, this expression enables the implementation of a hydroelastic analysis with the advantage of approximating more accurately t...
The built environment is expected to face major renewal and development across the wider Europe a... more The built environment is expected to face major renewal and development across the wider Europe and especially in the new member states of the European Union. The increasing societal demands for an environmentally friendly urban development as well as a variety of global issues, such as lifecycle sustainability and climate change impacts, require an integrative planning, design and construction of built systems based on lifecycle performance management. The vehicle to achieve these goals may be a European virtual knowledge and information framework for performance and risks associated with built systems. The major needs for establishing such a framework, the objectives and benefits, and the anticipated scientific deliverables are presented here. The collaboration with ongoing research projects with similar orientation is discussed. This paper accentuates the importance of and contributes towards a European approach for the development of built systems, based on shared understanding ...
Resilient systems present an inherent ability of recovering from a certain damage state reached d... more Resilient systems present an inherent ability of recovering from a certain damage state reached due to the application of a significant stress. The quantification of a system's resilience is a difficult task to perform because of: a) the system's complexity, b) the uncertain characteristics of the excitation force, c) the lack of specific elements to measure for an accu- rate assessment of a system's resilience, and d) the lack of robust tools for quantifying a sys- tem's resilience. Therefore, a decision maker requires both a methodology and the tools to decide for the most effective risk-response strategy. This paper presents such a methodology for a risk-based decision making for resilient systems. The proposed methodology involves the consideration of the following parameters: i) the variability of impact upon risk occurrence, ii) the available response strategies, and iii) the preference of the decision maker with regard to the criticality of the various impacts...
Operational …, 2006
Civil engineering projects include several uncertainties and risks, due to the special characteri... more Civil engineering projects include several uncertainties and risks, due to the special characteristics of construction industry. Time and cost are two parameters that could potentially lead to successful and conforming to regulations production of projects. It is imperative to estimate correctly the development and the final outcome of these parameters. Various tools have been applied in order to create trustworthy estimations. In this paper, a prototype system will be presented, which aims at predicting the final cost, based on information available at the bidding stage. The methodology will be based on a combination of regression analysis and case based reasoning in order to produce models for the prediction of final cost. These models will incorporate a process view and will depend on activity based costing methodology to estimate the process cost.
Applied Ocean Research, 2005
... The simplified approach of Jain [12] for the calculation of the mooring lines' s... more ... The simplified approach of Jain [12] for the calculation of the mooring lines' stiffness ... The floating body analysis is based on three-dimensional panel method utilizing Green's theorem. ... mooring lines, special attention is given to the computation of mooring lines' stiffness and drag ...
Environmental Security in Harbors and Coastal Areas: Management using Comparative Risk Assessment and Multi-Criteria Decision Analysis, 2007
Coastal zones are dynamically evolving systems comprising three components, i.e. the marine, the ... more Coastal zones are dynamically evolving systems comprising three components, i.e. the marine, the coastal, and the land subsystem. This is a typical division of a coastal zone and the only common feature that two different coastal zones may present. Concerning other features such as landscape morphology, ecological habitats, land uses, residential development and economic activities, etc., coastal zones present a multivariate environment with various characteristics. In general, there may be three different typologies of coastal zones based on morphological criteria. However, the number of coastal zones types is extremely increased when the specific conditions met in each one of these types are taking into consideration. Several types of human settlements and habitats along with various processes of human and natural origin render an environment with many inter-dependencies and risks.
Electronics
Offshore wind turbine (OWT) installations are continually expanding as they are considered an eff... more Offshore wind turbine (OWT) installations are continually expanding as they are considered an efficient mechanism for covering a part of the energy consumption requirements. The assessment of the energy potential of OWTs for specific offshore sites is the key factor that defines their successful implementation, commercialization and sustainability. The data used for this assessment mainly refer to wind speed measurements. However, the data may not present homogeneity due to incomplete or missing entries; this in turn, is attributed to failures of the measuring devices or other factors. This fact may lead to considerable limitations in the OWTs energy potential assessment. This paper presents two novel methodologies to handle the problem of incomplete and missing data. Computational intelligence algorithms are utilized for the filling of the incomplete and missing data in order to build complete wind speed series. Finally, the complete wind speed series are used for assessing the ene...
Journal of Management in Engineering, May 1, 1999
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Papers by Demos Angelides
realization of this framework will provide a sound base for sustainable coastal zone management in Greece.
The identification, classification and presentation of a comprehensive list of this type of risks shall provide B.O.T. project practitioners with a useful tool in the effort of setting up successfully a B.O.T. concession agreement. The presented approach provides a practical insight into 27 financial risks, which are associated with the Β.Ο.Τ. projects in their lifecycle. This is achieved through proper justification and description of the content of each risk. Furthermore, a categorization of the risks is presented, according to the stage they occur and the sources of their origin. The findings of this research would facilitate the risk analysis process that is being conducted by risk managers prior to bid for a B.O.T. project and during the negotiation period.