A bi-objective genetic algorithm approach to risk mitigation in project scheduling

A problem of risk mitigation in project scheduling is formulated as a bi-objective optimization problem, where the expected makespan and the expected total cost are both to be minimized. The expected total cost is the sum of four cost components: overhead cost, activity execution cost, cost of reducing risks and penalty cost for tardiness. Risks for activities are predefined. For each risk at an activity, various levels are defined, which correspond to the results of different preventive measures. Only those risks with a probable impact on the duration of the related activity are considered here. Impacts of risks are not only accounted for through the expected makespan but are also translated into cost and thus have an impact on the expected total cost. An MIP model and a heuristic solution approach based on genetic algorithms (GAs) is proposed. The experiments conducted indicate that GAs provide a fast and effective solution approach to the problem. For smaller problems, the results obtained by the GA are very good. For larger problems, there is room for improvement

A biobjective genetic algorithm approach to project scheduling under risk

A problem of risk mitigation in project scheduling is formulated as a bi-objective optimization problem, where the expected makespan and the expected total cost are both to be minimized. The expected total cost is the sum of four cost components: overhead cost, activity execution cost, cost of reducing risks and penalty cost for tardiness. Risks for activities are predefined. For each risk at an activity, various levels are defined, which correspond to the results of different preventive measures. Only those risks with a probable impact on the duration of the related activity are considered here. Impacts of risks are not only accounted for through the expected makespan but are also translated into cost and thus have an impact on the expected total cost. An MIP model and a heuristic solution approach based on genetic algorithms (GAs) is proposed and tested. The experiments conducted indicate that GAs provide a fast and effective solution approach to the proble m. For smaller problems, the results obtained by the GA are very good. For larger problems, there is room for improvement

Practical Implementation of Contract Administration Performance Model in Qatar Construction Projects

Globally, the performance of Construction Contract Administration (CCA) is becoming of significant interest as the industry suffers from notable delays, cost overruns, and disputes as a consequence of poor contract administration practices. In Qatar, the pace of projects will continue after hosting the FIFA 2022 World Cup to achieve the 2030 Qatar National Vision and beyond, therefore, monitoring of the proper CCA implementation and performance is necessary. Due to the wide scope and complicated nature of CCA, there is yet no consensus on how to assess its performance. This study briefly presents a systematic, operational, and multi-dimensional construction Contract Administration Performance Framework (CAPF) consisting of 93 CCA key measures/ tasks categorized in 11 CCA dimensions/process groups. The proposed framework is validated by structural equation modeling and subsequently, the Contract Administration Performance Model (CAPM) model was established. Through this study, the CAPM and its components are briefly explained, and then implemented on a real-world sample of 13 small, medium, and major construction projects in Qatar covering both public and private sectors, and then the performance is benchmarked. It is found that the model provides an operational basis for measuring the CCA Group Performance Indices (GPI), the overall Construction Contract Administration Performance Index (CCAPI) and support the identification of underperforming groups. The benchmarking value for the CCAPI (77.5%) demonstrates that the level of CCA performance is good. Also, the benchmarking values of GPI (range 74.3% to 87.8%) are good, except risk management (GPI= 50.5%), which needs an improvement program

A model of Black Sea circulation with strait exchange (2008–2018)

The Bosphorus exchange is of critical importance for hydrodynamics and hydroclimatology of the Black Sea. In this study, we report on the development of a medium-resolution circulation model of the Black Sea, making use of surface atmospheric forcing with high space and time resolution, climatic river fluxes and strait exchange, enabled by adding elementary details of strait and coastal topography and seasonal hydrology specified in an artificial box on the Marmara Sea side. Particular attention is given to circulation, mixing and convective water mass formation processes in the model, which are then compared with observations. Open boundary conditions relaxed to seasonal hydrology specified in the artificial box are found to enable Bosphorus exchange with a proper upper layer, lower layer and net fluxes comparable to the observed ranges. These improvements at the artificial boundary and in the interior evolution of the Black Sea allow the study to capture daily, seasonal to decadal climatic variability and change observed in the Black Sea in the last few decades.publishedVersio

Construction safety risk assessment with introduced control levels

It is of great importance to facilitate the risk assessment process in construction projects because risk assessment is a requirement in most legislation and safety standards. A great majority of construction SMEs (Small and Medium Enterprises) are not familiar with risk assessment concepts and methods. In particular, SMEs are very likely to have difficulty finding the qualified personnel or time to carry out a proper risk assessment. The method introduced in this paper has some distinct features. The method introduces a new method of risk assessment, replacing the traditional definition of probabilities with control levels because they are easier to implement and yield more accurate risk scores. The method was practically applied on 22 construction SMEs. From the practical application, it was observed that the method was found to be user friendly and the SMEs found it easy to update their risk strategies during various construction stages in their projects. The proposed risk assessment method introduces a powerful and practical control level strategy which would develop a safer, healthier and more competitive workplace for construction SMEs

Assessment of abnormally low tenders: a multinomial logistic regression approach

This study was performed in order to reveal factors affecting abnormally low tenders (ALTs) and to minimize negative effects of them. A thorough literature review was carried out to observe past research about the reasons of and possible solutions to ALTs. A questionnaire was prepared and submitted to construction professionals to capture negative impacts of ALTs based on the interviews with experts and past literature. 430 companies responded to the questionnaire. The data analysis was carried out by the multinomial logistic regression statistical tool. Having quality control systems and restricted procedure with prequalification procurement systems were main significant factors to reduce ALTs. Based on all significant factors, recommendations were made to construction professionals and companies to reduce adverse effects of ALTs. First published online: 18 Sep 201

International Conference on Civil Infrastructure and Construction (CIC 2020)

This is the proceedings of the CIC 2020 Conference, which was held under the patronage of His Excellency Sheikh Khalid bin Khalifa bin Abdulaziz Al Thani in Doha, Qatar from 2 to 5 February 2020. The goal of the conference was to provide a platform to discuss next-generation infrastructure and its construction among key players such as researchers, industry professionals and leaders, local government agencies, clients, construction contractors and policymakers. The conference gathered industry and academia to disseminate their research and field experiences in multiple areas of civil engineering. It was also a unique opportunity for companies and organizations to show the most recent advances in the field of civil infrastructure and construction. The conference covered a wide range of timely topics that address the needs of the construction industry all over the world and particularly in Qatar. All papers were peer reviewed by experts in their field and edited for publication. The conference accepted a total number of 127 papers submitted by authors from five different continents under the following four themes: Theme 1: Construction Management and Process Theme 2: Materials and Transportation Engineering Theme 3: Geotechnical, Environmental, and Geo-environmental Engineering Theme 4: Sustainability, Renovation, and Monitoring of Civil InfrastructureThe list of the Sponsors are listed at page 1

Assessing the risk perception of cost overrun through importance rating

Cost overrun in construction projects is a common issue affecting project performance. After a review of the literature, a list of 39 cost overrun attributes were gathered and presented in a survey. The survey was distributed online to construction professionals. 101 complete responses were received and analyzed by importance index, frequency index, cost index, frequency adjusted cost index, Spearman’s rank correlation, student’s t-test, risk assessment and factor analysis. The results of the survey revealed that the main causes of cost overrun in construction industry include inaccurate cost estimation, improper planning and scheduling, unrealistic contract duration and requirements, frequent changes to the scope of work, frequent design changes, inadequate labor/skill availability, inflation on costs of machinery, labor, material and transportation