No description available.

No description available.

Thesis (M.B.A.)--University of Hong Kong, 1991.

356 Leaves printed single pages, preliminary pages i-xxii and numbered pages. Includes bibliography. List of tables, list of figures and abbreviations. / Thesis (PhD)--University of Stellenbosch, 2004. / ENGLISH ABSTRACT:Decisions affecting construction projects are often characterised by uncertainty. One of the sources of this uncertainty is the unit costs used in detail cost estimates. Analytical techniques are available to model these uncertainties, but information is required to quantify it. Historical data is the preferred source of information, but due to unavailability and unreliability it hampers the application of the analytical techniques. Changes in the construction environment necessitate the improvement of data sources and the utilisation thereof in a structured, comprehensive and integrated manner. The purpose of this study is to determine how decision-making can be improved by enhanced information capturing and usage of relevant data for improved cost calculations. This is achieved by investigating the various components of an information system, viz. dataflow, data source, data application, and shown how an integrated development of each of these components with processmodelling, database development and quantitative risk analysis can lead to improved decision-making. This is achieved by the conceptual redevelopment and development of information systems for decision support in two different construction environments, viz. road and dam construction, respectively. During the research it was found that processmodelling can contribute to the improvement of dataflow in the fragmented construction environment, but that shortcomings exist in the processmodelling tools. A method, based on set and graph theory, was developed to address it. It was also found that database development provides the opportunity to improve the quality of data stored in electronic format. A comprehensive database model to store all information relevant to construction costs, specifications and legal documents with the required error checking mechanisms was developed. The benefit of modelling the global uncertainty of project cost estimates with probabilistic techniques such as Monte Carlo simulation and the Limit State Cost Function, whilst including the effects of correlation, is also shown. The information gained from historical data-analysis, besides the application in the probabilistic techniques, was used to identify properties such as impact, variability and correlation. It was found in the study that a shortage of descriptive information, whether it be at project or item level, is predominately the source of variability in unit cost data after errors have been removed. In order to identify the information that would contribute to the lowering of variability a method was developed by using influence factors and unit cost correlation mechanisms to identify the most influential factors for data capturing. This led to the development of an ideal data-application model in which all the relevant data used in the different cost-estimation phases, viz. long term, conceptual and detail, would be captured and used. Based on what was found, a generic information system development model was proposed that indicated the interaction of all the aspects that were investigated. Two of the model’s foremost properties are its self-triggering process and incremental development (improvement). On top of this development model a development process was designed that can be used for the structured, comprehensive and integrated development/redevelopment of an information system for cost calculation. / AFRIKAANSE OPSOMMING:Besluite in konstruksieprojekte word gereeld gekenmerk deur onsekerheid. Een van die bronne van onsekerheid is die eenheidtariewe wat tydens detailkosteberekeninge gebruik word. Analitiese tegnieke is beskikbaar om die onsekerhede te modelleer. Inligting word egter benodig om die onsekerhede mee te kwantifiseer. Die voorkeur bron van inligting is historiese data, maar weens onbeskikbaarheid en lae akkuraatheid daarvan striem dit die aanwending van die analitiese tegnieke. Veranderde omstandighede in die konstruksiebedryf noodsaak egter die verbetering van databronne en aanwending daarvan op ’n gestruktureerde, omvattende en geïntegreerde wyse. Die doel van hierdie studie is om te bepaal hoe besluitneming verbeter kan word deur inligtingversameling en benutting van relevante data vir konstruksiekosteberekeninge te verbeter. Dit word gedoen deur die onderskeie aspekte wat deel vorm van ’n inligtingstelsel, nl. die datavloei, datastoring en aanwending te ondersoek en te toon hoe geïntegreerde ontwikkeling van elk van hierdie aspekte met behulp van prosesmodellering, databasisontwikkeling en kwantitatiewe risiko-analise, ’n bydrae kan maak tot verbeterde besluitneming. Dit word gedoen deur twee verskillende omgewings, nl. padbou en dambou, as moontlike toepassingsomgewings te gebruik vir onderskeidelik die herontwikkeling en ontwikkeling van so ’n inligtingstelsel vir besluitneming. Tydens die ondersoeke is dit gevind dat prosesmodellering ’n waardevolle bydrae kan lewer tot die verbetering van datavloei in die gefragmenteerde konstruksie-omgewing, maar dat tekortkominge in die modelleringsprogramme bestaan. ’n Metode, gebaseer op versameling- en grafiekteorie, is ontwikkel om hierdie aspekte aan te spreek. Dit is ook gevind dat databasisontwikkeling die geleentheid bied om die kwaliteit van elektronies gestoorde databronne te verbeter. ’n Datamodel wat omvattend genoeg is om al die inligting wat met konstruksiekoste, spesifisering en regsdokumente verbandhou te stoor, is ontwikkel met die nodige fout-onderskeppingsmeganismes. Die nut van probabilistiese tegnieke soos Monte Carlo-simulasie en die Limietstaat Kostefunksie om die globale onsekerheid van projekte se kosteberamings te modelleer en die effek van korrelasie op die resultate in ag te neem, is ook getoon. Die inligting afkomstig van historiese data-ontleding, naas die aanwending in die probabilistiese tegnieke, is gebruik om die eienskappe soos impak, veranderlikheid en korrelasiemeganismes, te bepaal. Dit is in die studie gevind dat ’n tekort aan beskrywende inligting, hetsy op projek- of itemvlak, die oorwegende bron van veranderlikheid is nadat foutiewe data verwyder is. Om egter die beskrywende inligting te bepaal wat ’n bydrae kan maak tot die verlaging van hierdie veranderlikheid is ’n metode ontwikkel met behulp van invloedfaktore en eenheidtariefkorrelasiemeganismes om die mees omvangryke faktore te bepaal vir onderskepping. Dit het aanleiding gegee tot die ontwikkeling van ’n ideale data-aanwendingmodel waarin al die relevante inligting vir die verskillende fases van kosteberekening, nl. langtermyn, konseptueel en detail, onderskep en gebruik word. Gebaseer op dit wat gevind is, is ’n generiese inligtingstelsel ontwikkelingmodel voorgestel wat die interaksie van al die aspekte wat ondersoek is ten opsigte van mekaar toon. Twee van die hoofkenmerke van hierdie model is die selfvoerende proses en die inkrementele ontwikkeling van die stelsel. Op hierdie ontwikkelingmodel is ’n ontwikkelingproses gebou wat gebruik kan word vir die gestruktureerde, omvattende en geïntegreerde ontwikkeling/herontwikkeling van ’n inligtingstelsel vir kosteberekeninge.

It has been suggested that projects in the construction industry are subject to risks more than other industries. However, there is often little parity in allocation of risks in the construction industry. Usually, project participants allocate risks by aversion where owners tend to shift risks to the primary contractor, who in turn transfers them to the subcontractors. As a result of this, risks are not necessarily allocated/ re-allocated to the party that is best able to manage them efficiently and effectively. Risk allocation can significantly influence the behavior of the project participants and hence affects project schedule, cost and performance. Inappropriate risk allocation has led to adversarial relationships between contracting participants and has consequently increased project cost. The objective of this dissertation is to shed light on the current practices of risk allocation in the construction industry. The dissertation consists of three sections. The first section investigates and evaluates the problems of the current practice of risks allocation and their impacts on project performance. The second section investigates, identifies, and classifies barriers to optimal risk allocation. The third section looks into allocating construction risk from a more cooperative and rational perspective. The goal is to provide the construction industry with a rational decision-making mechanism that will provide an alternative to the current practice of typically allocating risks by aversion. To meet the objectives, structured survey questionnaires for Sections One and Two were used. The first survey found that the current practice of risk allocation has four major problems. These problems include: 1. Dispute, claims and tension leads to adversarial relationships. 2. Competitive relationship leads to aggressive relationships. 3. Subjective pricing of risk leading to higher contingency. 4. Allocation by aversion that leads to misallocation of risks. The second survey found thirteen barriers to optimal risk allocation, which were classified into three main categories: behavioral, technical, and organizational barriers. Lack of an efficient risk allocation mechanism ranks at the top of the identified barriers. These findings were linked, in causal-effects relationships, to formulate an analytic model for the current practice of risk allocation. This dissertation uses the research findings and the rational decision-making process to develop a practical mechanism for optimizing risk allocation. The developed mechanism was then fine-tuned and validated by a Delphi expert panel technique. The developed mechanism should aid construction industry professionals and construction project participants in making rational and economical risk allocation decisions to alleviate the identified above-mentioned problems, overcome the identified barriers, and improve project efficiency by minimizing the negative impacts of the current practice of risk allocation on project cost, schedule and overall project performance. / Graduation date: 2013 / Access restricted to the OSU Community at author's request from Jan. 4, 2013 - July 4, 2013