Anna Morpurgo

What's the fun in informatics? working to capture children and teachers into the pleasure of computing

The importance of computer science education in secondary, and even primary school, has been pointed out by many authors. But too often pupils only experience ICT, both at home and at school, and confuse it with computer science. We organized a game-contest, the KangourouofInformatics, with the aim to attract all pupils (not only the talented ones), expose them to the scientific aspects of informatics in a fun way, and convey a correct conception of the discipline. Peculiarities of the game are its focus on team work and on engaging pupils in discovering what lays behind what they experience every day.

Informatics Education in Italian Secondary Schools

This article describes the state of informatics education in the Italian secondary schools, highlighting how the learning objectives set up by the Ministry of Education are difficult to meet, due to the fact that the subject is often taught by teachers not holding an informatics degree, the lack of suitable teaching material and the expectations of pupils and families, who tend to identify informatics with the use of computer applications.

Exploring the processing of formatted texts by a kynesthetic approach

We describe a teaching activity about word-processors we proposed to a group of 25 pupils in 9th/10th grades of an Italian secondary school. While the pupils had some familiarity with word-processor operations, they had had no formal instruction about the automatic elaboration of formatted texts. The proposed kinesthetic/tactile activities turned out to be a good way for conveying non-trivial abstract computing concepts.

How Challenging are Bebras Tasks?: An IRT Analysis Based on the Performance of Italian Students

This paper analyses the results of the 2014 edition of the Italian Bebras/Kangourou contest, exploiting the Item Response Theory statistical methodology in order to infer the difficulty of each of the proposed tasks starting from the scores attained by the participants. Such kind of analysis, enabling the organizers of the contest to check whether or not the difficulty perceived by pupils was substantially different from that estimated by those who proposed the tasks, is important as a feedback in order to gain knowledge to be used both in ranking participants and in organizing future editions of the contest. We show how the proposed analysis essentially highlights that the 63% of tasks was perceived at the same level of difficulty estimated by those who proposed them, but a 37% of tasks were either easier or more difficult than expected.

Is Coding the Way to Go

Recently, several actions aimed at introducing informatics concepts to young students have been proposed. Among these, the “Hour of Code” initiative addresses a wide audience in several countries worldwide, with the goal of giving everyone the opportunity to learn computer science. This paper compares Hour of Code with an alternative, yet similar, approach which we believe is more effective in exposing pupils to the scientific value of the informatics discipline.

Polynomial uniform convergence and polynomial-sample learnability

In this work we study the relationship between PAC learning and theproperty of uniform convergence. We define the concept of<?Pub Fmt italic>polynomial uniform convergence<?Pub Fmt /italic> ofrelative frequencies to probabilities in thedistribution–dependent context. Let<?Pub Fmt italic>X<subscrpt>n</subscrpt> =(0,1)<subscrpt>n</subscrpt><?Pub Fmt /italic>, let<?Pub Fmt italic>P<subscrpt>n</subscrpt><?Pub Fmt /italic> be aprobability distribution on<?Pub Fmt italic>X<subscrpt>n</subscrpt><?Pub Fmt /italic> and let<inline-equation><f>F<inf>n</inf>⊂2^x<inf>n</inf></f></inline-equation> be a class of events. The family{(<?Pub Fmt italic>X<subscrpt>n</subscrpt>, P<subscrpt>n</subscrpt>,F<subscrpt>n</subscrpt><?Pub Fmt /italic>)}n≥1 is said to bepolynomially uniformly convergent if, for all<?Pub Fmt italic>n<?Pub Fmt /italic>, the probability that the maximum difference (over<?Pub Fmt italic>F<subscrpt>n</subscrpt><?Pub Fmt /italic>) between therelative frequency and probability of an event exceed a given positiveε is at most δ (0 < δ < 1), when the sample on whichthe frequency is evaluated has size polynomial in<?Pub Fmt italic>n<?Pub Fmt /italic>, 1/ε, 1/δ. Givena<?Pub Fmt italic>t<?Pub Fmt /italic>-sample(<?Pub Fmt italic>x<subscrpt>1</subscrpt>,…,x<subscrpt>t</subscrpt><?Pub Fmt /italic>),let<?Pub Fmt italic>C<subscrpt>n</subscrpt><supscrpt>(t)</supscrpt>(x<subscrpt>1</subscrpt>,…,x<subscrpt>t</subscrpt><?Pub Fmt /italic>)be the Vapnik-Chervonenkis dimension (VCdim) of the set(x<subscrpt>1</subscrpt>,…x<subscrpt>t</subscrpt><inline-equation><f>∩</f></inline-equation> f | f <inline-equation><f><g>e</g></f></inline-equation> F<subscrpt>n</subscrpt> and<?Pub Fmt italic>M(n,t)<?Pub Fmt /italic> the expectation<?Pub Fmt italic>E(C<subscrpt>n</subscrpt><supscrpt>(t)</supscrpt>/t)<?Pub Fmt /italic>.The results we obtain are: <list><item>1. (X<subscrpt>n</subscrpt>,P<subscrpt>n</subscrpt>,F<subscrpt>n</subscrpt>)n≥1 is polynomially uniformly convergent iffthere exists β > 0 such that<?Pub Fmt italic>M(n,t)=O(n/t<supscrpt>β</supscrpt>)<?Pub Fmt /italic>. </item><item>2. The family {(X<subscrpt>n</subscrpt>,F<subscrpt>n</subscrpt>)}n≥1 is polynomially uniformly convergent forall probability distributions<?Pub Fmt italic>P<subscrpt>n</subscrpt><?Pub Fmt /italic> on<?Pub Fmt italic>X<subscrpt>n</subscrpt><?Pub Fmt /italic> iff VCdim(<?Pub Fmt italic>F<subscrpt>n</subscrpt><?Pub Fmt /italic>) isbounded by a polynomial <?Pub Fmt italic>p(n)<?Pub Fmt /italic> iff (X<subscrpt>n</subscrpt>, F<subscrpt>n</subscrpt>)≥1 ispolynomial–sample learnable. </item><item>3. If (X<subscrpt>n</subscrpt>, P<subscrpt>n</subscrpt>,F<subscrpt>n</subscrpt>) is polynomially uniformly convergent then(X<subscrpt>n</subscrpt>, P<subscrpt>n</subscrpt>, F<subscrpt>n</subscrpt>)≥1 is polynomial–sample learnable, butthere exist polynomial–sample learnable families(X<subscrpt>n</subscrpt>, P<subscrpt>n</subscrpt>, F<subscrpt>n</subscrpt>)≥1 which do not satisfy the property ofpolynomial uniform convergence. </item></list>

Nothing to Fear but Fear Itself: Introducing Recursion in Lower Secondary Schools

Recursion is a powerful conceptual tool, nevertheless it is often considered too abstract and technical to be effectively proposed in lower secondary school. Here we present our experience in introducing 8th graders to recursive strategies where the active observation of recursive algorithms execution allowed pupils to understand the main features of a recursive process, to convince themselves that it works, and to unveil the mystery of its effectiveness. In fact, by focusing on the self-similarity of the input data and the possibility to delegate blindly the solution of subproblems, pupils were able to recognize the heuristic potential of recursion. We started with an unplugged activity using LEGO bricks where a recursive algorithm was executed by pupils, and we continued with an activity supported by a software tool we developed ad-hoc. The undertaking was concluded by the abstract consolidation of the basic concepts and properties which had come out during the previous activities.

Promoting Computational Thinking Skills: Would You Use this Bebras Task?

Bebras, an international challenge organized on an annual basis in several countries (50 in 2016), has the goal of promoting informatics and computational thinking through attractive tasks. We analyzed Bebras tasks by considering the Computational Thinking (CT) skills each task promotes, starting from the operational definition of CT developed by the International Society for Technology in Education (ISTE) and the ACM-founded Computer Science Teachers Association (CSTA). We argue that such an approach is indeed well-suited to present Bebras tasks, especially with the goal to use them in curricular teaching: framing them as CT enablers helps in making explicit their educational potential, that can be appreciated also by teachers without a formal education in informatics and adapted to a wide range of ages and schools. We explored the viability of our approach by interviewing teachers of different kinds of schools. We propose to use these CT skills also as a tool to classify Bebras tasks, which results in a more uniform distribution of tasks, w.r.t. the one obtained by leveraging content topics.

A low-cost instrument for environmental particulate analysis based on optical scattering

This paper presents the design, realization and calibration of a portable instrument for real-time measurement (concentration and size distribution) of airborne dust particles. The measuring principle is the estimation of the light scattered by the particles under illumination. The proposed design is characterized by low hardware cost and simplicity of calibration but, nevertheless, it delivers significant performance in terms of size resolution. This result could be achieved by means of an accurate processing of the detected signal, which maximizes the signal/noise ratio in detecting the scattering peaks. In order to get this signal processing chain running in real time on a low-cost platform (an ARM7-based microcontroller board), computationally efficient algorithms have been developed for optimal filtering and peak detection. For the metrological calibration of the instrument, a simple method is proposed, which employs commonly available materials with known particle size distribution, instead of expensive monodispersed test particles. The experimental results show the effectiveness of the proposed calibration and the ability of the instrument to reach a sensitivity and a granulometric resolution comparable to those of more sophisticated instruments.

Learning Greedy Strategies at Secondary Schools: An Active Approach

We describe an extra-curricular learning unit for students of upper secondary schools, focused on the discovery of greedy strategies. The activity, based on the constructivistic methodology, starts by analyzing the procedure naturally arising when we aim at minimizing the total number of bills and coins used for giving change. This procedure is used as a prototype of greedy algorithms, whose strategies are formalized and subsequently applied to a more general scheduling problem with the support of an ad hoc developed software.