This paper proposes and validates a model-driven software engineering technique for spreadsheets. The technique that we envision builds on the embedding of spreadsheet models under a widely used spreadsheet system, so that models and their conforming instances are developed under the same environment. In practice, this convenient environment enhances evolution steps at the model level while the corresponding instance is automatically co-evolved. Finally, we have designed and conducted an empirical study with human users in order to assess our technique in production environments. The results of this study are promising and suggest that productivity gains are realizable under our model-driven spreadsheet development setting.

We investigated imidazolium-based ionic liquid (IL) interactions with human serum albumin (HSA) to discern the level of cation interactions towards protein stability. STD-NMR spectroscopy was used to observe the imidazolium IL protons involved in direct binding and to identify the interactions responsible for changes in Tm as accessed by differential scanning calorimetry (DSC). Cations influence protein stability less than anions but still significantly. It was found that longer alkyl side chains of imidazolium- based ILs (more hydrophobic) are associated with a higher destabilisation effect on HSA than short-alkyl groups (less hydrophobic). The reason for such destabilisation lies on the increased surface contact area of the cation with the protein, particularly on the hydrophobic contacts promoted by the terminus of the alkyl chain. The relevance of the hydrophobic contacts is clearly demonstrated by the introduction of a polar moiety in the alkyl chain: a methoxy or alcohol group. Such structural modification reduces the degree of hydrophobic contacts with HSA explaining the lesser extent of protein destabilisation when compared to longer alkyl side chain groups: above [C2mim]+. Competition STD-NMR experiments using [C2mim]+, [C4mim]+ and [C2OHmim]+ also validate the importance of the hydrophobic interactions. The combined effect of cation and anion interactions was explored using 35Cl NMR. Such experiments show that the nature of the cation has no influence on the anion–protein contacts, still the nature of the anion modulates the cation–protein interaction. Herein we propose that more destabilising anions are likely to be a result of a partial contribution from the cation as a direct consequence of the different levels of interaction (cation–anion pair and cation–protein).

This paper presents ES-SQL, an embedded tool for visually constructing queries over spreadsheets. This tool provides an expressive query environment which has knowledge on the business logic of spreadsheets, and by this knowledge it assists the user in defining the intended queries.

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During the last years several projects and studies have improved the knowledge about Textile Reinforced Mortar (TRM) technology. TRM has already been used in strengthening masonry and reinforced concrete structural elements such as walls, arches, columns and beams. This material is presented as a real alternative to the use of fibre-reinforced polymers (FRP) in situations where these composites have presented some drawbacks or their use is banned. Textile Reinforced Mortar show a complex mechanical behaviour derived from the heterogeneity of the constituent materials. This paper aims to deepen the knowledge of this composite material in terms of tensile behaviour. Following this scope, this paper presents an experimental campaign focused on thirty one TRM specimens reinforced with four different reinforcing ratios. The results are analysed and contrasted with two distinct models. i) the Aveston-Cooper-Kelly theory (ACK) which is based on a tri-linear analytical approach; and ii) a nonlinear numerical simulation with a 3D Finite Element code. The Finite Element Analysis (FEA) of the TRM tensile tests also showed no significant dependence on the basalt-to-mortar interface, i.e., the choice of a bond-slip curve in order to reproduce the bond stresses and slippages along the interface is irrelevant and it can be simply considered as rigid interface.

Nowadays, modern analysis of Civil Engineering structures implies the use of increasingly sophisticated computer models, designed not only to predict the response of actual structures to different loadings, but also to simulate the effects of eventual modifications in their structural configuration. Nevertheless, it is often discovered that, when the numerical simulations are compared with experimental data, the degree of correlation is weak preventing the use of the FE models with confidence in further analyses. In such cases, FE updating techniques are available to correct the FE models, based on dynamic response records of the real structures. These updating processes usually consist of four phases: a preliminary FE modeling, an experimental modal identification, a manual sensitivity analysis and, finally, an updating of the FE model. The present paper presents all four phases of a successful updating process for the FE model of a footbridge structure. It is shown how the last phase of the process can be performed fully automatically, by coupling an optimization routine with a commercial FE analysis program.

This paper presents a tool, dubbed FaultySheet Detective, for aiding in spreadsheet fault localization, which combines the detection of bad smells with a generic spectrum-based fault localization algorithm.

Let \(\alpha\) and \(\beta\) be orientation-preserving diffeomorphisms (shifts) of \(\mathbb{R}_+=(0,\infty)\) onto itself with the only fixed points \(0\) and \(\infty\), where the derivatives \(\alpha'\) and \(\beta'\) may have discontinuities of slowly oscillating type at \(0\) and \(\infty\). For \(p\in(1,\infty)\), we consider the weighted shift operators \(U_\alpha\) and \(U_\beta\) given on the Lebesgue space \(L^p(\mathbb{R}_+)\) by \(U_\alpha f=(\alpha')^{1/p}(f\circ\alpha)\) and \(U_\beta f= (\beta')^{1/p}(f\circ\beta)\). We apply the theory of Mellin pseudodifferential operators with symbols of limited smoothness to study the simplest singular integral operators with two shifts \(A_{ij}=U_\alpha^i P_++U_\beta^j P_-\) on the space \(L^p(\mathbb{R}_+)\), where \(P_\pm=(I\pm S)/2\) are operators associated to the Cauchy singular integral operator \(S\), and \(i,j\in\mathbb{Z}\). We prove that all \(A_{ij}\) are Fredholm operators on \(L^p(\mathbb{R}_+)\) and have zero indices.

Nowadays there is a clear increase of products or tailored solutions with the goal of better adept to the needs of
clients. In another context there is a wide growth of computers’ presence in the class rooms, in order to assist
the teacher to captivate and motivate the students using educational games. However not all teachers have the
advanced computer knowledge that would allow them to personalize games, which would benefit children by
providing tailored solutions to their specific needs. Having this problem into consideration it was designed/idealized a system that relies on a framework of game creation that allows a user with less informatics skills to create a game based on a model. Although there are many games of this type it would be useful and innovative for a teacher to be able to create a game that is personalized to the students’ needs and according to the skills that they wish to develop. This system consists in an interface where the user has to follow some established steps, in order to achieve a file containing all the game features, which is later imported to
a framework. That system allows the creation of different games, as long as these games come under the same game mechanics.

GAMES AND THE LEARNING OF MATHEMATICS OUTSIDE THE CLASSROOM
H. Rocha

Universidade Nova de Lisboa, Faculdade de Ciências e Tecnologia (PORTUGAL)

Playing games is a recreational activity that is also highly recognized as a potentially rich activity for the teaching and learning. It is an activity that involves the recognition and observance of rules, as well as the development of strategies to achieve victory. It is thus an activity that encourages compliance with rules but also the development of learning and therefore has a socializing character while stimulating critical thinking and analysis of situations. This is why many authors think about playing games as a problem-solving activity with great potential for the learning of mathematics. However, a review of the literature suggests that mathematical learning does not always occur, pointing to the relevance of the specific features of the game and the circumstances in which it is used. Looking to contribute to a better understanding of these issues, the project that was the basis of this study focuses on the use of games by middle school students, intending to promote their mathematical learning in a voluntary and informal context, outside the classroom. The games were available in MatLab, a room of the school supervised by mathematics teachers, which students could visit in their leisure time. In this communication I intend to analyze how the visits to MatLab contributed to the mathematical learning of students, considering the influence of specific characteristics of the games and the atmosphere created in MatLab, given the students’ previous mathematical knowledge.

The study adopts a qualitative and interpretative methodological approach, undertaking two student case studies. Data collection was completed over three months and included observation of twenty visits of these students to MatLab. Data collection was made through the development of a logbook, audio record of the students’ visits and two interviews to the students and to their teacher. Data analysis was based on the evidence gathered in the light of the problem under study.

The conclusions reached stress the importance of certain features of the games to promote student engagement, leading to a desire for self-improvement, very important for the development of sustained learning. Computer games have proven to have a stronger potential to engage students than board games. Nevertheless, the most important characteristics of a game seem to be related to the possibility of playing at different mathematical levels (without getting blocked by lack of knowledge) and to the possibility of keep getting better marks (without the existence of a maximum level from which evolution is not possible). In what concerns to achievement in mathematics’ classes, the students’ teacher reports an improvement in mathematics knowledge (more evident in the average achiever student) as well as an increase in students’ involvement in class work (more evident in the low achiever student).

keywords: game-based learning, mathematics, informal learning.

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This paper presents a graphical interface to query model-driven spreadsheets, based on experience with previous work and empirical studies in querying systems, to simplify query construction for typical end-users with little to no knowledge of SQL. We briefly show our previous text based model-driven querying system. Afterwards, we detail our graphical model-driven querying interface, explaining each part of the interface and showing an example. To validate our work, we executed an empirical study, comparing our graphical querying approach to an alternative querying tool, which produced positive results.

Given a monoid defined by a presentation, and a homotopy base for the derivation graph associated to the presentation, and given an arbitrary subgroup of the monoid, we give a homotopy base (and presentation) for the subgroup. If the monoid has finite derivation type (FDT), and if under the action of the monoid on its subsets by right multiplication the strong orbit of the subgroup is finite, then we obtain a finite homotopy base for the subgroup, and hence the subgroup has FDT. As an application we prove that a regular monoid with finitely many left and right ideals has FDT if and only if all of its maximal subgroups have FDT. We use this to show that a finitely presented regular monoid with finitely many left and right ideals satisfies the homological finiteness condition FP3 if all of its maximal subgroups satisfy the condition FP_3.