Human resource allocation to multiple projects based on members’ expertise, group heterogeneity, and social cohesion

Project managers regularly allocate human resources to construction projects. This critical task is usually executed by fulfilling the minimum project staffing requirements, normally based around the quantity and competence of project members. However, research has shown that team performance can increase by up to 10% and 18%, respectively, as a consequence of the group members’ heterogeneity and social cohesion. There is currently no practical quantitative tool that incorporates these aspects, allowing project managers to achieve this task efficiently and objectively. A new quantitative model for the effective allocation of human resources to multiple projects, which takes group heterogeneity and social cohesion into account, is proposed. This model is easy to build, update, and use in real project environments with the use of a spreadsheet and a basic optimization engine (e.g., Excel Solver). A case study is proposed and solved with a genetic algorithm to illustrate the implementation of the model. Finally, a validation example is provided to exemplify how group heterogeneity and social cohesion condition academic achievement in an academic setting

Structural resistance of reinforced concrete buildings in areas of moderate seismicity and assessment of strategies for structural improvement

© 2017 by the authors. Moderate magnitude seismic events have occurred during the last decade in non-seismic areas and have highlighted that many existing buildings do not sufficiently resist these types of events. The objective of this work is to illustrate that most buildings dating from 2002-2010 constructed from wide beams, which were designed to previous earthquake resistance codes, do not offer a satisfactory seismic behaviour, and to identify which structural attributes can best help alleviate this problem. In this work the effect of a real earthquake of medium magnitude (Lorca, 2011) on buildings of three, five and eight stories with unidirectional frames of wide-beam concrete was assessed. The methodology included non-linear static (pushover) analyses and dynamic response simulations with the aim to understand the effect on the seismic performance of changing some of the geometrical and material parameters. Maximum displacements and capacity curves for the top floor of a set of representative buildings were evaluated and compared. In particular, capacity curves obtained from non-linear static (pushover) analysis are compared for different building configurations, as well as the maximum displacements obtained through non-linear dynamic analysis. This paper highlights the seismic vulnerability of buildings constructed between 2002 and 2010 and the results indicate that a higher density of infill walls (walls whose bricks are not part of the main structure) is the feature that most significantly improves the seismic behaviour of the structures analysed. Moreover, counterintuitively, incorporating stronger concrete and reinforcing steel and using alternative column arrangements only have a small positive effect on the seismic behaviour of these types of buildings

Economic scoring formulae in multi-Attribute construction auctions

Copyright © 2017 ISEC Press. Public tendering implies the free concurrence and competition of bidding companies that certify their solvency, so that those companies proposing the most attractive bid, both technically and economically, are awarded the contracts and carry them out according to the same terms and conditions that they proposed. Generally, there is high competition in public tendering, both concerning the number of bidders (constantly increasing), as well as the profit margin (constantly decreasing). On the other side, handling the procurement process, there is a contracting authority that spends public money while trying to fulfill a particular socio-economic objective. This paper will take the contracting authority's (auctioneer's) point of view which is in charge of devising and implementing the awarding criteria, as well as choosing the best bidder. Particularly, this paper will focus on some aspects of the Economic Scoring Formula (ESF) design. The ESF constitutes a set of mathematical expressions that transform the economic bids submitted by the bidders into scores, so that, eventually, the bidders can be ranked and the best one selected. We will conclude that, despite apparently simple, how ESF are configured eventually have profound consequences on bidding behavior and some bidding results, like a higher or lower bid dispersion

Be prepared for your next 30-second T&L conversation

Many relevant bits of our social and professional interactions happen within a few seconds after starting conversations with someone else. Additionally, within the academia, lecturers are frequently exposed to student’s complaints or alternative points of view which may challenge the way Teaching and Learning (T&L) is being managed. However, students may not speak up when they are asked for feedback, but in out-of-context situations instead. At that moment, the (unprepared) lecturer needs to come up with a good answer. No postponement is allowed and, generally, this lecturer will just have around 30 seconds to go over his/her major points in a clear and comprehensible manner. This paper reviews the reasons why some innovative teaching methods generally cause some level of discomfort among the students. Examples about the usual complaints that they raise are also analysed. Finally, a series of short dialogues involving both peers and students as locutors and exemplifying how these conversations generally evolve are included. By means of these short dialogues the reader can better prepare him/herself for key T&L-related difficult conversations. Anticipating these conversations is relevant because they involve delicate issues about the way the instructor approaches innovative teaching and how the students perceive them. Therefore, this paper provides reflections and additional tools for new lecturers who try to implement T&L innovations and that have to deal with some opposition among the students

Explaining the Bayes' theorem graphically

The Bayes’ theorem on conditional probabilities is normally presented to students in introductory courses/modules on Statistics and Probability. This because most STEM students will make use of conditional probabilities in their professional lives with or without noticing. However, maybe because of the unfamiliar notation or because of the variety of ways in which this theorem can be formulated, most students have trouble understanding it. Moreover, when it comes to practical applications and problem exercises, most students (who have generally memorised its manifold ways of rearranging the conditional probabilities formula along with a few applications) struggle even more to come up with correct solutions. By means of a completely graphical approach, this paper presents an alternative way of explaining the Bayes’ theorem to STEM students. By means of diagrams and schematics the students can see the conditional probabilities represented as areas in a square. Simple geometric operations with these areas (additions and multiplications mostly) allow them, not just to understand this theorem far quicker, but to apply it confidently in almost any possible problem configuration. Overall, this paper offers an alternative or complementary way of explaining this important theorem more clearly to students that take probability courses by conveying it graphically instead of with the traditional mathematical formulae. Through a representative case study, this paper deals provides first-hand evidence about how confusing to understand the Bayes’ theorem might be at first even in simple problems, and how the understanding of this theorem is dramatically improved when presenting it graphically

Non-linear time-cost trade-off models of activity crashing: Application to construction scheduling and project compression with fast-tracking

When shortening a project’s duration, activity crashing, fast-tracking and substitution are the three most commonly employed compression techniques. Crashing generally involves allocating extra resources to an activity with the intention of reducing its duration. To date, the activity time-cost relationship has for the most part been assumed to be linear, however, a few studies have suggested that this is not necessarily the case in practice. This paper proposes two non-linear theoretical models which assume either collaborative or non-collaborative resources. These models closely depict the two most common situations occurring during construction projects. The advantages of these models are that they allow for both discrete and continuous, as well as deterministic and stochastic configurations. Additionally, the quantity of resources required for crashing the activity can be quantified. Comparisons between the models and another recent fast-tracking model from the literature are discussed, and a Genetic Algorithm is implemented for a fictitious application example involving both compression techniques

Mathematical relationships between scoring parameters in capped tendering

Mathematical relationships between Scoring Parameters can be used in Economic Scoring Formulas (ESF) in tendering to distribute the score among bidders in the economic part of a proposal.Each contracting authority must set an ESF when publishing tender specifications and the strategy of each bidder will differ depending on the ESF selected and the weight of the overall proposal scoring.This paper introduces the various mathematical relationships and density distributions that describe and inter-relate not only the main Scoring Parameters but the main Forecasting Parameters in any capped tender (those whose price is upper-limited).Forecasting Parameters, as variables that can be known in advance before the deadline of a tender is reached, together with Scoring Parameters constitute the basis of a future Bid Tender Forecasting Model. © 2012 Elsevier Ltd. APM and IPMA

Efficiency of evolutionary algorithms in water network pipe sizing

© 2015, Springer Science+Business Media Dordrecht. The pipe sizing of water networks via evolutionary algorithms is of great interest because it allows the selection of alternative economical solutions that meet a set of design requirements. However, available evolutionary methods are numerous, and methodologies to compare the performance of these methods beyond obtaining a minimal solution for a given problem are currently lacking. A methodology to compare algorithms based on an efficiency rate (E) is presented here and applied to the pipe-sizing problem of four medium-sized benchmark networks (Hanoi, New York Tunnel, GoYang and R-9 Joao Pessoa). E numerically determines the performance of a given algorithm while also considering the quality of the obtained solution and the required computational effort. From the wide range of available evolutionary algorithms, four algorithms were selected to implement the methodology: a PseudoGenetic Algorithm (PGA), Particle Swarm Optimization (PSO), a Harmony Search and a modified Shuffled Frog Leaping Algorithm (SFLA). After more than 500,000 simulations, a statistical analysis was performed based on the specific parameters each algorithm requires to operate, and finally, E was analyzed for each network and algorithm. The efficiency measure indicated that PGA is the most efficient algorithm for problems of greater complexity and that HS is the most efficient algorithm for less complex problems. However, the main contribution of this work is that the proposed efficiency ratio provides a neutral strategy to compare optimization algorithms and may be useful in the future to select the most appropriate algorithm for different types of optimization problems

Viability of green roofs as a flood mitigation element in the central region of Chile

Population increase and urban development over the last 20 years in Chile have outgrown most rainwater drainage and evacuation systems. Many cities located in the central region suffer from frequent floods in some of their sectors during winter rainfall events. In addition, the lack of green spaces in these cities leads to biodiversity loss, increasing temperatures, greater energy demands, etc. Green roofs offer a solution that can mitigate climate change by reducing the runoff in cities with extensive, highly impermeable areas. This work analyses the installation of green roofs as a potential solution to the sectorial floods suffered by many cities in central Chile. The methodology includes the identification of conflictive sectors in the city of Curicó, hydrological modelling with the Storm Water Management Model (SWMM) software, the consideration of different distributions and types of green roof surfaces, and computational simulations to determine the feasibility of green roofs for preventing floods. The results show that, for moderate rainfall events, all studied sectors could avoid flooding if at least 50% of the surrounding area had green roofs (irrespective of the type of green roof). In contrast, in the presence of strong rainfall events, only some semi-extensive and extensive green roofs covering 60% to 95% of the surrounding area, respectively, could prevent floodin

Making the most of pre-class assignments

When teaching a course, the lecturer or teaching instructor may need that students read some material before coming to the next face-to-face session. Counting on students that have done their assignments and that have done them well, allows the lecturer to make quicker and deeper progress in the contact session. It also raises motivation and allows devoting more time to hands-on practice rather than lecturing, the latter being a method that has proven to reach very low retention levels among students. However, getting the students to read and work on their assignments is easier said than done, and many lecturers feel compelled to set in-class tests and quizzes in order to lure the students to fulfil their homework tasks. However, in-class tests and quizzes are also time-expensive, both inside and outside the classroom, and they are not exempt of other disadvantages. In this paper, we will go over some methods that Teaching and Learning research has found to promote high levels of student understanding and retention, but that are generally too time-consuming to implement them on a regular basis. Also, drawing on the authors’ experience and other research studies, we will present some alternative methods that are almost as effective as the former but require significantly lower time resources