Human-Computer-Interaction (HCI) is a key topic on the Accessibility area, namely in what concerns a Smart-City environment, where humans have to interact with artefacts spread all around one particular city. In the last decade HCI has experienced a significant evolution towards a desired fully natural user interface, for example in what concerns the ability to recognize a wide range of hand gestures in real-time. Some efforts have lately been made in the hardware sector in order to deploy sensors that may gather information about the human body movements, as detailed as possible. One example of this effort is the Kinect Sensor from Microsoft. Nevertheless, although these solutions provide a solution for the body movement, they lack on the details, namely the hands, given their small dimension compared to the body as a whole. In other words, the SDKs provided by the vendors of these devices usually lack on the needed details concerning hand movements that would be needed for an accurate hand gesture recognition implementation. This paper presents an extension to the Kinect SDK based on a contour analysis for the estimation of the hand position. This algorithms are then used to provide the creation of a gesture library that might be used afterwards.

Heterogeneity is omnipresent in today’s commodity computational systems, which comprise at least one multi-core Central Processing Unit (CPU) and one Graphics Processing Unit (GPU). Nonetheless, all this computing power is not being exploited in mainstream computing, as the programming of these systems entails many details of the underlying architecture and of its distinct execution models. Current research on parallel programming is addressing these issues but, still, the systems’ heterogeneity is exposed at language level.
This paper proposes a uniform framework, grounded on the Single Operation Multiple Data model, for the programming of such heterogeneous systems. The model is declarative, empowering the compiler to generate code for multiple architectures from the same source. To this extent, we designed a simple extension of the Java programming language that embodies the model, and developed a compiler that generates code for both multi-core CPUs and GPUs. A performance evaluation attests the validity of the approach that, despite being based on a simple programming model, is able to deliver performance gains on par with hand-tuned data parallel multi-threaded Java applications.

Abstract The strain rate dependent mechanical behaviour was studied for the common out-of-autoclave aerospace textile composite 5-harness-satin carbon�epoxy. End-loaded 15 � , 30 � and 45 � off-axis and 90 � compression tests were carried out at three different strain rate levels ( 4 � 10 - 4 s - 1 , 200 s - 1 and 1000 s - 1 ) to determine the effect of strain rate for transverse compression and combined transverse compression/in-plane shear loading. The dynamic tests were carried out on a split-Hopkinson pressure bar, where high speed photography and digital image correlation allowed a detailed study of the specimen deformation and failure process. Quasi-static reference tests were carried out on an electro-mechanical test machine using the same specimen type and a static \{DIC\} system. Pronounced strain rate effects on the axial stress�strain response were observed for all specimen types. Failure envelopes for the combined s 22 c - t 12 stress state were derived from the experimental data and compared with the maximum stress criterion, which appears well suited to approximate the experimental failure envelope at all strain rate levels. It was observed that the failure envelope was simply scaled up with increasing strain rate, while the overall shape was found to be strain rate independent.

Semantic Sensor Web is a new trend of research integrating Semantic Web technologies with sensor networks. It uses Semantic Web standards to describe both the data produced by the sensors, but also the sensors and their networks, which enables interoperability of sensor networks, and provides a way to formally analyze and reason about these networks. Since sensors produce data at a very high rate, they require solutions to reason efficiently about what complex events occur based on the data captured. Nevertheless, besides detecting complex events, sensor based applications also need to execute actions in response to these events, and in some cases, to execute these actions in a transactional way. In this paper we propose TRev as a solution to combine the detection of complex events with the execution of transactions for these domains. TRev is an abstract logic to model and execute reactive transactions. The logic is parametric on a pair of oracles defining the basic primitives of the domain, which makes it suitable for a wide range of applications. In this paper we provide oracle instantiations combining RDF/OWL and relational database semantics for TRev Afterwards, based on these oracles, we illustrate how TRev can be useful for these domains.

Abstract This paper proposes a hybrid methodology for the evaluation of integrated inductors sensitivity against technological/geometrical parameters variation. The obtained results are used in an optimization-based design environment for integrated inductors, as a way of guaranteeing that obtained solutions are robust against parameter variation. For the inductor characterization, a lumped element model is used, where each element value is evaluated through physics based equations. The sensitivity of the inductor characterization to parameter variations is evaluated at two levels. At the physical level, the sensitivity of the model element values to technological/geometrical parameters variations is computed through an equation-based strategy. Then, the sensitivity of the inductor characterization to the model parameter variations is obtained through a simulation-based approach, where the Richardson extrapolation technique is used for the calculation of the partial derivatives. Several examples considering the evaluation of sensitivity of both inductance and quality factor of two inductors in \{UMC130\} technology are presented. Obtained results are compared against Monte-Carlo simulations.

Eggshells from the three extant crocodilian species Crocodylus mindorensis (Philippine Crocodile), Paleosuchus palpebrosus (Cuvier's Smooth-fronted Caiman or Musky Caiman) and Alligator mississippiensis (American Alligator or Common Alligator) were prepared for thin section and scanning electron microscope analyses and are described in order to improve the knowledge on crocodilian eggs anatomy and microstructure, and to find new apomorphies that can be used for identification. Both extant and fossil crocodilian eggs present an ornamentation that vary as anastomo-, ramo- or the here newly described rugosocavate type. The angusticaniculate pore system is a shared character for Crocodylomorpha eggshells and some dinosaurian and avian groups. Previously reported signs of incubated crocodilian eggs were found also on our only fertilised and hatched egg. Paleosuchus palpebrosus presents unique organization and morphology of the three eggshell layers, with a relatively thin middle layer characterised by dense and compact tabular microstructure.

This study intends to characterize how the teacher uses and integrates the different representations provided by the graphing calculator on the process of teaching and learning functions at the secondary level. Specifically, it intends to understand the balance established between the use of the different representations, and the way these representations are articulated. The conclusions reached point to an active use of the graphic and algebraic representations and to a scarce use of the tabular representation. The conclusions also point to a flexible articulation between the two representations usual used, assuming different forms and frequently an interactive approach, repeatedly switching between representations.

THE IMPACT OF THE CULTURAL CONTEXT ON THE PROFESSIONAL PRACTICE OF THE TEACHER

H. Rocha

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

The professional knowledge is a key element of the teacher’s practice. This knowledge is naturally influenced by the teacher’s beliefs and conceptions and by his training, but the context where he develops his practice is perhaps the most decisive influence. At this level, the school where the teacher works and his colleagues are a powerful influence, but the characteristics of his students are even a stronger influence. The cultural diversity of the students and specifically the linguistic diversity are highly relevant elements. A classroom where different languages converge is always a complex context which requires a deeper professional knowledge with inevitable repercussions over the teacher’s practice.

This study focuses on a teacher working with a mathematics’ class of foreign students with heavy linguistic limitations on the language of instruction and it intends to analyze the impact of this context on the teacher’s practice. In particular, it intends to analyze how this context interferes with the characteristics of the tasks proposed by the teacher and with the way how mathematical concepts are presented to the students.

The study adopts a qualitative and interpretative methodological approach, undertaking one teacher case study. Data were collected during one school year by semi-structured interviews, class observation, and documental data gathering. All interviews and classes observed were audio taped and transcribed. Data analysis was conducted in an interpretative way.

The conclusions reached point to an increase on the appreciation of mechanization, to a large reduction in the use of problematic situations and to a presentation of Mathematics as calculation, disconnected from any application, and where reasoning appears as a marginal element or is even missing. The use of several examples becomes a key element of the practice of this teacher. The main finding of this study suggests that language limitations caused a strong impact on the practice of a teacher who considers the understanding and the development of reasoning from the discussion around mathematical ideas as central to the teaching of this subject. It was also possible to identify that the need to find a way to communicate reinforced the formalism of the mathematical language, placing it in the center of the learning process.

Keywords: cultural context, teacher’s practice, mathematics.

http://docentes.fct.unl.pt/lblm/files/jbic-2015-20-821.pdf

The usual difficulties of students regarding the choice of an appropriate window when using the graphing calculator in the study of functions and the importance of the teachers’ knowledge to overcoming them, led to this study. The main goal was to characterize the way teachers address the viewing window in the classroom, trying to infer aspects of the Knowledge for Teaching Mathematics with Technology that can justify that practice. The conclusions reached point to the importance of a set of specific knowledge where I highlight the knowledge of the students’ difficulties, the knowledge of mathematical content necessary to understand the impact of the viewing window on the graphic, and the knowledge of teaching strategies that address both the students’ difficulties and the relevant mathematical knowledge.

We prove that if the Hardy-Littlewood maximal operator is bounded on a separable Banach function space \(X(\mathbb{R}^n)\) and on its associate space \(X'(\mathbb{R}^n)\) and a maximally modulated Calderón-Zygmund singular integral operator \(T^{\Phi}\) is of weak type \((r,r)\) for all \(r\in(1,\infty)\), then \(T^{\Phi}\) extends to a bounded operator on \(X(\mathbb{R}^n)\). This theorem implies the boundedness of the maximally modulated Hilbert transform on variable Lebesgue spaces \(L^{p(\cdot)}(\mathbb{R})\) under natural assumptions on the variable exponent \(p:\mathbb{R}\to(1,\infty)\). Applications of the above result to the boundedness and compactness of pseudodifferential operators with \(L^\infty(\mathbb{R},V(\mathbb{R}))\)-symbols on variable Lebesgue spaces \(L^{p(\cdot)}(\mathbb{R})\) are considered. Here the Banach algebra \(L^\infty(\mathbb{R},V(\mathbb{R}))\) consists of all bounded measurable \(V(\mathbb{R})\)-valued functions on \(\mathbb{R}\) where \(V(\mathbb{R})\) is the Banach algebra of all functions of bounded total variation.

Abstract A modified Iosipescu specimen is proposed to measure the mode İI\} intralaminar fracture toughness and the corresponding crack resistance curve of fibre reinforced composites. Due to the impossibility of scaling the specimen, a modification of the classical size effect method is proposed. The calculation of the crack driving force curves is performed using the Finite Element Method. The classical Iosipescu shear feature was used and tests were coupled with digital image correlation to support the proposed approach. Experiments were performed on IM7/8552 material system and the R-curve was obtained. The steady-state value of the fracture toughness of the ply is found to be equal to R 0 ss = 34.4  kJ/m2.

Abstract This work addresses the experimental identification of mode I cohesive law of wood bonded joints. The approach combines the double cantilever beam (DCB) test with both digital image correlation (DIC) and embedded fibre Bragg grating (FBG) sensors. The spectrum geometric mean of the \{FBG\} reflected spectral response was determined, and the wavelength evolution was used to define the fracture process zone (FPZ) development phase. This evaluation allowed a consistent selection of experimental range of over which the identification procedure of mode I cohesive law is build up. Mode I crack length, Resistance-curve and cohesive law parameters are characterised and discussed. The strain energy release rate (GI) is determined from the P�d curve by the compliance-based beam method (CBBM). The crack tip opening displacement (wI) is determined by post-processing displacements measured by DIC. The cohesive law in mode I (sI�wI) is then obtained by numerical differentiation of the GI�wI relationship.

Abstract Several analyses of diversity through geological time use global, synoptic databases, and this practice often makes it difficult to distinguish true signals in changing diversity from regional-scale sampling and/or geological artefacts. Here we investigate how echinoid diversity changed through the Mesozoic of the Lusitanian basin in Portugal based on a comprehensive, revised database, and seek to distinguish biological signal from geological or environmental constraints. The observed diversity pattern is far from having a defined trend, showing many fluctuations that appear to be linked with gaps in the geological record. This study revealed that, independently of the method used, whether correlation tests or model fitting, the diversity signal is not completely explained by the studied sampling proxies. Among the different proxies, marine facies variation in combination with outcrop area best explains the palaeodiversity curve.

Supply Chain Design problems often result into multiperiod stochastic mixed integer problems that are hard to solve. In this paper we propose a metaheuristic algorithm as a specialization for two- stage problems of the so-named Fix-and-Relax Algorithm presented previously for solving large- scale multiperiod stochastic mixed 0-1 optimization problems under a time stochastic dominance risk averse strategy, so-named TSD. Some computational experience is presented.