Evaluation of control over the microbiological contamination of carcasses in a lamb carcass dressing process operated with or without pasteurizing treatment

The aim of this study was to quantify the hygienic status of a lamb slaughterhouse by means of multivariate statistical analysis, to demonstrate how the microbiological data could be exploited to improve the lamb slaughter process by constructing control charts and to evaluate the potential effect of an intervention step such as steam application on the microbiological quality of lamb carcasses. Results showed that pelt removal and evisceration were hygienically uncontrolled. TVC and Enterobacteriaceae progressively increased from the stage ‘after pelt removal of hind and forelegs/before final pulling’ to the stage ‘after evisceration/before pluck removal’ thus indicating possible deposition of microorganisms during these operations. It seems that the processing stages of freshly produced carcasses were better distinguished by Enterobacteriaceae, with evisceration contributing mostly to the final Enterobacteriaceae counts. Application of steam during the lamb slaughter process reduced microbial counts without adverse effects on the organoleptic characteristics of the carcasses. Moreover, the construction of control charts showed that decontamination with steam contributed to the maintenance of an in control process compared to that before the application of steam, suggesting the potential use of steam as an intervention step during the lamb slaughter process.     

Project cash flow analysis in the presence of uncertainty in activity duration and cost

The inherent uncertainty and imprecision in project scheduling have motivated the proposal of several fuzzy set theory based extensions of activity network scheduling techniques. Building upon these, a cash flow calculation methodology for projects including activities with fuzzy durations and/or costs is proposed in this paper. According to the proposed approach, the project cash flow is represented by an S-surface (as opposed to the traditional S-curve) ensuing by connecting S-curves at different risk possibility levels. The methodology is exemplified by estimating the working capital requirements in a real world road construction project. Furthermore, the benefits of the methodology and its subsequent computerization are discussed. It is believed that the proposed approach may also be useful for both evaluating project proposals during feasibility studies and for performing earned value analysis for project monitoring and control.     

Fuzzy Repetitive Scheduling Method for Projects with Repeating Activities

In projects with repeating activities (such as multistory buildings, highways, or pipelines consisting of reiterating identical or similar units) and in which the activity unit production rates are characterized by uncertainty or imprecision, fuzzy set theory and the well-established repetitive scheduling method (RSM) can be combined to ensure uninterrupted usage of resources between similar activities in different units. The reason for this approach is that in practice the application of RSM may be hindered by several considerations, for example, repetitive units may be slightly different from each other, the performance of construction crews may vary, and there may be complex resource matching and sharing between activities and work sites. The proposed methodology is termed fuzzy repetitive scheduling method (F-RSM), and it requires a generalization of RSM in which schedules are represented by two- or three-dimensional graphs and whereby the concepts of a control segment and the controlling sequence area are introduced. The resulting methodology addressing the original RSM scheduling problem is presented in this paper.     

A New Approach To The Development Of Computer-Aided Estimating Systems For The Construction Industry

Estimators display a diversity of approaches to their task of predicting the cost of a construction project. To design and build individualized, computer-aided estimating software products to reflect this diversity is however expensive. This paper describes a new method of designing and building such products which is quick, easy and hence inexpensive. The method relies upon embedding a core estimating product into a set of software tools which can be used to reshape and enhance the core functionality. The tools have been designed to minimize the requisite technical knowledge of the user, principally through the use of declarative features. The individualistic nature of estimating is therefore reflected in this new method of developing estimating products. These resultant products are therefore more acceptable to practising estimators.     

A compromise programming model for site selection of borrow pits

Road fill construction requires soil for filling low areas; this soil is obtained from temporary mineral workings known as ‘borrow pits’ (BP). Between a number of possible BPs, the appropriate site should be selected based upon conflicting econo‐technical and environmental criteria aiming at achieving optimal BP performance while minimizing the adverse impacts to human and natural resources. For solving this problem a model for BP selection has been developed by this research using compromise programming (CP). The model incorporates a hierarchical structure integrating criteria and sub‐criteria whose relative importance is set by the decision makers. Possible alternative BP sites are subsequently assessed on all these sub‐criteria. Based upon this analysis, the model determines the distance of each of the possible alternatives from the utopia (ideal) point; the option with the minimum distance is considered the best compromise. The relevant concepts are exemplified through the presentation of a case study concerning the BP site selection for an Egnatia Motorway section in northwest Greece. The main conclusion that can be drawn from this work is that the CP approach is appropriate and valid for BP selection and, furthermore, it may also be used for other multiple objective construction‐related site selection problems.