Resource Leveling of an Industrial Building Using Genetic Algorithm Technique

Construction companies should schedule their projects in a manner that considers theefficient use of limited resources in order to complete a project within estimated budget, onschedule and in compliance with the specifications. In this context, the planning of resourcesbecomes crucial for a construction project, which can be accomplished by resource leveling.Resource leveling - also known as resource smoothing - is a method that attempts to reducethe fluctuations in resource usage in order to make the resource requirements as uniform aspossible while maintaining the original project duration. The studies dealing with resource leveling problems can be classified into two categories, which are; (1) analytical methods and(2) heuristic methods. Analytical methods may give optimal solutions on small-scaledproblems; however, they are inadequate in large-scaled problems. As a result of theweaknesses of analytical methods, many studies have been conducted in order to developmore efficient models by heuristic methods. Genetic algorithm-based resource leveling is oneof these models, which is developed to attain better solutions. The main objective of thisstudy is to handle the resource leveling problem of an industrial building using geneticalgorithms. In this context, a schedule for an industrial building is established using theCritical Path Method (CPM). The information about the logical constraints and the resourcesrequired to carry out activities were obtained through the interviews with civil engineers fromthe company, whose expertise is on industrial buildings. The proposed genetic algorithmbased resource leveling model attempts to improve the schedule. The developed modelprovided a decrease of 20% in the total resource-days required to complete the project. Thestudy is of benefit to participants of construction industry, because it makes them aware of the potential use of the combination of critical path method and genetic algorithms in order to solve the resource leveling problem

Motivation of civil engineers and architects in Turkey

Motivation is one of the key factors that stimulate individuals to improve their productivity. Therefore, motivation of construction workers has been debated with considerable interest by participants in the construction industry. However, motivating only construction workers, but ignoring the motivation of construction professionals, viz., architects and civil engineers, may not be enough to successfully complete a construction project. Although motivation of construction professionals may also enhance the performance of a construction project, this topic is mostly ignored in the motivation literature. This study attempts to fill this gap by (1) identifying the motivators that are of importance to architects and civil engineers and (2) exploring the statistical difference between architects’ and civil engineers’ motivators. For this purpose, a questionnaire survey was administered to Turkish architects and civil engineers to collect data on their perceptions of the importance of different motivators. The case of Turkey is investigated because several of the larger Turkish contractors undertake construction projects outside their home country. Statistical analysis was performed on the collected data to verify whether there are statistically significant differences in the perception of some motivators by architects and civil engineers. The study demonstrates the existence of a statistically significant difference between architects’ and civil engineers’ motivators. Identifying the architects’ and civil engineers’ motivators may help construction companies in motivating their architects and civil engineers more effectively, thus developing a quality workforce

Impacts of different objective functions on resource leveling in construction projects: a case study

A review of the recent literature on the models that focus on resource leveling in Critical Path Method networks shows that different objective functions have been used to optimize resource utilization. The main objective of this study is to investigate the impacts of using different objective functions on resource utilization histograms in Critical Path Method networks. For this purpose, nine different resource leveling objective functions were optimized via a genetic algorithm-based model. The model was developed using actual data obtained from a steel framed industrial building construction project. It was found that each of these objective functions generates different resource utilization histograms. In order to determine the improvement levels achieved by resource leveling using nine different objective functions, the improvement percentage in each parameter and the average improvement percentage for each objective function were calculated. Even though the objective function that involves the minimization of the sum of the square of the deviations in daily resource usage provided the best average improvement percentage in the studied case, another objective function(s) may provide better average improvement percentage in different projects. The contractor should consider all objective functions for resource leveling and select the one(s) that provides the best average improvement percentage

Detecting unbalanced bids via an improved grading-based model

Unbalanced bidding, also known as skewed bidding, is the process of increasing and/or decreasing the prices of various bid items without altering the total offered bid price. Bids can be unbalanced either mathematically (front-end loading) or materially (quantity error exploitation). Owners should be very careful when evaluating the tenders as awarding a contract to an unbalanced bid may result in severe cost overruns because the prices of those items do not reflect their true costs and markup allocations. Unbalanced bidding is still a contentious issue in the construction industry. While some researchers consider it as a legal bidding strategy in such a fierce competitive business environment, others view it as an unethical practice and claim that unbalanced bids should be disqualified. Studies regarding unbalanced bidding can be categorized into two groups: (1) the ones focusing on detecting or preventing this practice to help owners; and 2) the ones focusing on optimizing unbalanced bidding to help contractors. This study aims to develop a model, which consists of eight grading systems, to assist owners in detecting materially unbalanced bids. The proposed model is the improved version of the previous model, which was composed of five grading systems. In order to demonstrate how this grading-based model can be used by owners, an illustrative example is presented. It was found that owners can easily and successfully detect unbalanced bids via the proposed mode

The effect of adjunctive chlorhexidine mouthrinse on GCF MMP-8 and TIMP-1 levels in gingivitis : a randomized placebo-controlled study

Peer reviewe

Oral Health Status and Oral Hygiene Habits of an Adult Turkish Population on Dialysis

WOS: 000207968300005PubMed ID: 18399306Purpose: The present study was undertaken to evaluate the oral health status and oral hygiene habits of dialysis patients. Materials and Methods: A total of 145 patients on dialysis were evaluated in two centres. Evaluation included oral examination of soft and hard tissues and completion of a questionnaire that was used to gather information about demographic, socioeconomic, medical and dental status and oral hygiene attitudes of patients. Awareness of the importance of oral health was also determined by four yes/no questions within this questionnaire. Results: Of the 145 patients, 89(61.4%) were presently candidates for renal transplantation. Nineteen patients (13.1%) were edentulous and nearly half of the patients (n = 69, 47.6%) had 15 or fewer remaining teeth. Dentate patients who regularly brushed twice a day and flossed were few (n = 18, 14.3%; n = 3, 2.4%, respectively). In addition, plaque score was more than 50% in most of the dentate patients (93.7%). Gingival bleeding was reported by about two thirds of dentate patients (67.5%). None of the patients were referred to a dentist or were attending regular dental care. The percentage of patients who were aware of oral cavity-related infections and importance of oral hygiene following renal transplantation was very low (20.7% and 9.7%, respectively). Conclusions: Poor oral health, unsatisfactory daily oral hygiene habits and insufficient awareness of the importance of oral health is frequent among Turkish dialysis patients. Dentists and nephrologists should work in close cooperation in order to raise awareness and encourage regular dental controls