Combining Generic Programming and Service-Oriented Architectures for the Effective and Timely Development of Complex e-Learning Systems

Peer-reviewed

Automatització de l’estació FESTO MPS2000C

L’Escola Politècnica Superior de la Universitat de Vic disposa d’una cèl·lula de fabricació didàctica de la marca FESTO que simula un procés d’assemblatge d’una comanda. Aquesta cèl·lula esta composta per quatre estacions diferenciades que poden treballar de forma independent o de forma conjunta, l’estació palets, l’estació plaques, l’estació cinta i l’estació magatzem. Cada estació és un conjunt de sensors i actuadors controlats per mitjà d’un PLC, aquests estan interconnectats a través d’un bus industrial. L’objectiu d’aquest treball consisteix en realitzar la substitució dels PLC’s, decidir el funcionament que han de tenir les estacions, instal·lar una pantalla tàctil pel control del procés i realitzar la programació de tots els elements. Aquest projecte ha estat realitzat en cinc fases principals: 1. Estudi i coneixement de les estacions, en aquesta fase s’ha estudiat els diferents sensors i actuadors que les conformen, així com el funcionament d’aquestes amb el programa i PLC’s antics. 2. Instal·lació i cablejat dels nous PLC’s i de la pantalla tàctil. 3. Estudi sobre el nou funcionament que han de seguir les estacions. 4. Programació dels nous dispositius seguint el funcionament acordat. 5. Posada en marxa del sistema i realització de proves. 6. Realització de la memòria del projecte, on s’expliquen les característiques i el funcionament de totes les estacions i de la pantalla tàctil. La conclusió que s’ha extret d’aquest treball és que l’automatització d’un procés de fabricació tot i que suposa un esforç inicial a nivell de recursos, un cop realitzada la instal·lació suposa una millora de l’eficiència del sistema. És per això que la indústria cada cop més tendeix a automatitzar els seus processos, no només per millorar la competitivitat, sinó també per realitzar tasques que les persones no poden executar de forma eficient o segura.

Un análisis comparativo del papel del bucle fonológico versus la agenda visoespacial en el cálculo en niños de 7-8 años = A comparative analysis of the phonological loop versus the visuo-spatial sketchpad in mental arithmetic tasks in 7-8 y.o. children

En esta investigación se ha estudiado la relación entre dos subsistemas de la memoria de trabajo (buclefonológico y agenda viso-espacial) y el rendimiento en cálculo con una muestra de 94 niños españolesde 7-8 años. Hemos administrado dos pruebas de cálculo diseñadas para este estudio y seis medidassimples de memoria de trabajo (de contenido verbal, numérico y espacial) de la «Batería de Testsde Memoria de Treball» de Pickering, Baqués y Gathercole (1999), y dos pruebas visuales complementarias.Los resultados muestran una correlación importante entre las medidas de contenido verbaly numérico y el rendimiento en cálculo. En cambio, no hemos encontrado ninguna relación con las medidasespaciales. Se concluye, por lo tanto, que en escolares españoles existe una relación importanteentre el bucle fonológico y el rendimiento en tareas de cálculo. En cambio, el rol de la agenda viso-espaciales nulo

Performance evaluation of MPEG-4 Video encoder on Adres

Actualment un típic embedded system (ex. telèfon mòbil) requereix alta qualitat per portar a terme tasques com codificar/descodificar a temps real; han de consumir poc energia per funcionar hores o dies utilitzant bateries lleugeres; han de ser el suficientment flexibles per integrar múltiples aplicacions i estàndards en un sol aparell; han de ser dissenyats i verificats en un període de temps curt tot i l’augment de la complexitat. Els dissenyadors lluiten contra aquestes adversitats, que demanen noves innovacions en arquitectures i metodologies de disseny. Coarse-grained reconfigurable architectures (CGRAs) estan emergent com a candidats potencials per superar totes aquestes dificultats. Diferents tipus d’arquitectures han estat presentades en els últims anys. L’alta granularitat redueix molt el retard, l’àrea, el consum i el temps de configuració comparant amb les FPGAs. D’altra banda, en comparació amb els tradicionals processadors coarse-grained programables, els alts recursos computacionals els permet d’assolir un alt nivell de paral•lelisme i eficiència. No obstant, els CGRAs existents no estant sent aplicats principalment per les grans dificultats en la programació per arquitectures complexes. ADRES és una nova CGRA dissenyada per I’Interuniversity Micro-Electronics Center (IMEC). Combina un processador very-long instruction word (VLIW) i un coarse-grained array per tenir dues opcions diferents en un mateix dispositiu físic. Entre els seus avantatges destaquen l’alta qualitat, poca redundància en les comunicacions i la facilitat de programació. Finalment ADRES és un patró enlloc d’una arquitectura concreta. Amb l’ajuda del compilador DRESC (Dynamically Reconfigurable Embedded System Compile), és possible trobar millors arquitectures o arquitectures específiques segons l’aplicació. Aquest treball presenta la implementació d’un codificador MPEG-4 per l’ADRES. Mostra l’evolució del codi per obtenir una bona implementació per una arquitectura donada. També es presenten les característiques principals d’ADRES i el seu compilador (DRESC). Els objectius són de reduir al màxim el nombre de cicles (temps) per implementar el codificador de MPEG-4 i veure les diferents dificultats de treballar en l’entorn ADRES. Els resultats mostren que els cícles es redueixen en un 67% comparant el codi inicial i final en el mode VLIW i un 84% comparant el codi inicial en VLIW i el final en mode CGA.

Programa de gestió per la Pastisseria Mas

En els últims anys, el món de la informàtica ha evolucionat d'una manera inimaginable, tan a nivell de Hardware com de Software. Aquesta evolució ha donat lloc a la creació de moltes empreses dedicades a la programació, on una de les seves principals feines ha estat la realització de programes de gestió d'empreses. Moltes vegades, però, els programes estàndards no poden satisfer el total de les necessitats dels clients, sinó algunes d’aquestes i realitzar un programa personalitzat té un cost elevat. En el cas de la Pastisseria Mas de Navàs, una empresa familiar, per poder realitzar les tasques administratives utilitzen fulls de càlcul, concretament el Microsoft Excel, que permet portar els comptes d'una manera més o menys senzilla, ja que només són necessàries unes nocions bàsiques d'informàtica. El mateix passa amb les dades dels proveïdors, que les guarden en una Base de Dades del tipus Microsoft Access. Una altra de les mancances és el tema dels encàrrecs que es fa de manera manual. Per tant, l’objectiu d’aquest projecte, és realitzar un programa que els hi faciliti la seva activitat. Aquest programa els permetrà gestionar les dades que utilitzen, com la informació sobre els clients, personal, comandes... També s’ha desenvolupat una web que permet obtenir informació sobre les comandes que s’han realitzat. Aquesta aplicació està dissenyada per funcionar en l’entorn Windows XP i s’ha desenvolupat amb el compilador de CodeGear Rad Studio, concretament el C++ Builder 2009. A nivell de base de dades, he utilitzat MySQL i en el cas de la pàgina web, PHP i lamateixa base de dades. L’anàlisi i el disseny ha estat fet en UML.

Sistemes encastats en temps real

En l’actualitat, els sistemes electrònics de processament de dades són cada cop més significatius dins del sector industrial. Són moltes les necessitats que sorgeixen en el món dels sistemes d’autentificació, de l’electrònica aeronàutica, d’equips d’emmagatzemament de dades, de telecomunicacions, etc. Aquestes necessitats tecnològiques exigeixen ser controlades per un sistema fiable, robust, totalment dependent amb els esdeveniments externs i que compleixi correctament les restriccions temporals imposades per tal de que realitzi el seu propòsit d’una manera eficient. Aquí és on entren en joc els sistemes encastats en temps real, els quals ofereixen una gran fiabilitat, disponibilitat, una ràpida resposta als esdeveniments externs del sistema, una alta garantia de funcionament i una àmplia possibilitat d’aplicacions. Aquest projecte està pensat per a fer una introducció al món dels sistemes encastats, com també explicar el funcionament del sistema operatiu en temps real FreeRTOS; el qual utilitza com a mètode de programació l’ús de tasques independents entre elles. Donarem una visió de les seves característiques de funcionament, com organitza tasques mitjançant un scheduler i uns exemples per a poder dissenyar-hi aplicacions.

Implementació de la metodologia Scrum en una empresa de desenvolupament de Software

L’organització de la producció és sempre un factor clau en qualsevol empresa. No hi ha cap fórmula magistral que pugui servir per a tothom, perquè aquesta és molt depenent del sector i de la mida. Softvic S.A., l’empresa on treballo, em va demanar que implantés un sistema d’organització adequat a una empresa de desenvolupament de Software. Les empreses d’aquesta tipologia tenen dues característiques diferenciadores respecte una empresa de fabricació: les feines es fan una única vegada i es redefineixen freqüentment els projectes a fer al futur. És a dir, els requisits són inestables i requereixen rapidesa i flexibilitat. Actualment, Softvic S.A. ja té la ISO 9001:2008 al departament de programació. Aquesta ISO contempla com es creen les ordres de programació (OP) i ordres d’incidència (OI) i com es registra i avalua la feina realitzada. L’objectiu és implantar una metodologia que s’encarregui de la part anterior a aquesta, és a dir, definir les feines a fer en un període. Això s’ha d’integrar perfectament amb la part ja recolzada per la ISO. Per aquest fet es va escollir la metodologia Scrum que complia tots els requisits esmentats i estava contrastada per diferents empreses del món del Software. Primerament es van fer proves en les quals es guardava la informació en un Excel i s’imprimien manualment les feines a realitzar. Un cop es va haver decidit quina informació era útil i quina no en el cas de Softvic, es va crear una base de dades amb les taules i camps necessaris. Per treballar de forma més còmoda es va fer posteriorment un programa per a mantenir les dades i un formulari per imprimir etiquetes. A mesura que hem anat utilitzant la metodologia Scrum, hem anat ajustant aspectes cap on hem cregut convenient pel nostre cas en particular.

Programming and analysing measurement experiments using the PicoCricket system

The aim of this project is to get used to another kind of programming. Since now, I used very complex programming languages to develop applications or even to program microcontrollers, but PicoCricket system is the evidence that we don’t need so complex development tools to get functional devices. PicoCricket system is the clear example of simple programming to make devices work the way we programmed it. There’s an easy but effective way to programs mall devices just saying what we want them to do. We cannot do complex algorithms and mathematical operations but we can program them in a short time. Nowadays, the easier and faster we produce, the more we earn. So the tendency is to develop fast, cheap and easy, and PicoCricket system can do it.

La Adquisición de competencias básicas en educación primaria: una aproximación interdisciplinar desde la didáctica de la lengua y de las matemáticas

Este artículo trata de la aplicación de las competencias básicas en el currículum de Educación Primaria. El objetivo que persigue es ofrecer algunas estrategias para ayudar a los maestros a integrar las competencias básicas en los métodos de programación y evaluación. Con este fin, y para prever las posibles dificultades en la implementación de las competencias básicas, en la primera parte del artículo se analiza la situación actual a partir de la lectura de diversos documentos legales vigentes. A continuación, en la segunda parte del artículo se aportan algunas herramientas para facilitar esta integración desde las áreas de lengua y de matemáticas. Realizamos esta aproximación desde la didáctica de la lengua y de las matemáticas por su carácter instrumental para la adquisición de otros conocimientos

Learning Robot Motions from Visual Sensing

Learning from demonstration becomes increasingly popular as an efficient way of robot programming. Not only a scientific interest acts as an inspiration in this case but also the possibility of producing the machines that would find application in different areas of life: robots helping with daily routine at home, high performance automata in industries or friendly toys for children. One way to teach a robot to fulfill complex tasks is to start with simple training exercises, combining them to form more difficult behavior. The objective of the Master’s thesis work was to study robot programming with visual input. Dynamic movement primitives (DMPs) were chosen as a tool for motion learning and generation. Assuming a movement to be a spring system influenced by an external force, making this system move, DMPs represent the motion as a set of non-linear differential equations. During the experiments the properties of DMP, such as temporal and spacial invariance, were examined. The effect of the DMP parameters, including spring coefficient, damping factor, temporal scaling, on the trajectory generated were studied.

Promoting Programming Learning. Engagement, Automatic Assessment with Immediate Feedback in Visualizations

The skill of programming is a key asset for every computer science student. Many studies have shown that this is a hard skill to learn and the outcomes of programming courses have often been substandard. Thus, a range of methods and tools have been developed to assist students’ learning processes. One of the biggest fields in computer science education is the use of visualizations as a learning aid and many visualization based tools have been developed to aid the learning process during last few decades. Studies conducted in this thesis focus on two different visualizationbased tools TRAKLA2 and ViLLE. This thesis includes results from multiple empirical studies about what kind of effects the introduction and usage of these tools have on students’ opinions and performance, and what kind of implications there are from a teacher’s point of view. The results from studies in this thesis show that students preferred to do web-based exercises, and felt that those exercises contributed to their learning. The usage of the tool motivated students to work harder during their course, which was shown in overall course performance and drop-out statistics. We have also shown that visualization-based tools can be used to enhance the learning process, and one of the key factors is the higher and active level of engagement (see. Engagement Taxonomy by Naps et al., 2002). The automatic grading accompanied with immediate feedback helps students to overcome obstacles during the learning process, and to grasp the key element in the learning task. These kinds of tools can help us to cope with the fact that many programming courses are overcrowded with limited teaching resources. These tools allows us to tackle this problem by utilizing automatic assessment in exercises that are most suitable to be done in the web (like tracing and simulation) since its supports students’ independent learning regardless of time and place. In summary, we can use our course’s resources more efficiently to increase the quality of the learning experience of the students and the teaching experience of the teacher, and even increase performance of the students. There are also methodological results from this thesis which contribute to developing insight into the conduct of empirical evaluations of new tools or techniques. When we evaluate a new tool, especially one accompanied with visualization, we need to give a proper introduction to it and to the graphical notation used by tool. The standard procedure should also include capturing the screen with audio to confirm that the participants of the experiment are doing what they are supposed to do. By taken such measures in the study of the learning impact of visualization support for learning, we can avoid drawing false conclusion from our experiments. As computer science educators, we face two important challenges. Firstly, we need to start to deliver the message in our own institution and all over the world about the new – scientifically proven – innovations in teaching like TRAKLA2 and ViLLE. Secondly, we have the relevant experience of conducting teaching related experiment, and thus we can support our colleagues to learn essential know-how of the research based improvement of their teaching. This change can transform academic teaching into publications and by utilizing this approach we can significantly increase the adoption of the new tools and techniques, and overall increase the knowledge of best-practices. In future, we need to combine our forces and tackle these universal and common problems together by creating multi-national and multiinstitutional research projects. We need to create a community and a platform in which we can share these best practices and at the same time conduct multi-national research projects easily.

Early nutritional determinants in cardio-metabolic programming – A prospective randomized controlled dietary intervention study

Western societies have been faced with the fact that overweight, impaired glucose regulation and elevated blood pressure are already prevalent in pediatric populations. This will inevitably mean an increase in later manifestations of cardio-metabolic diseases. The dilemma has been suggested to stem from fetal life and it is surmised that the early nutritional environment plays an important role in the process called programming. The aim of the present study was to characterize early nutritional determinants associating with cardio-metabolic risk factors in fetuses, infants and children. Further, the study was designated to establish whether dietary counseling initiated in early pregnancy can modify this cascade. Healthy mother-child pairs (n=256) participating in a dietary intervention study were followed from early pregnancy to childhood. The intervention included detailed dietary counseling by a nutritionist targeting saturated fat intake in excess of recommendations and fiber consumption below recommendations. Cardio-metabolic programming was studied by characterizing the offspring’s cardio-metabolic risk factors such as over-activation of the autonomic nervous system, elevated blood pressure and adverse metabolic status (e.g. serum high split proinsulin concentration). Fetal cardiac sympathovagal activation was measured during labor. Postnatally, children’s blood pressure was measured at six-month and four-year follow-up visits. Further, infants’ metabolic status was assessed by means of growth and serum biomarkers (32-33 split proinsulin, leptin and adiponectin) at the age of six months. This study proved that fetal cardiac sympathovagal activity was positively associated with maternal pre-pregnancy body mass index indicating adverse cardio-metabolic programming in the offspring. Further, a reduced risk of high split proinsulin in infancy and lower blood pressure in childhood were found in those offspring whose mothers’ weight gain and amount and type of fats in the diet during pregnancy were as recommended. Of note, maternal dietary counseling from early pregnancy onwards could ameliorate the offspring’s metabolic status by reducing the risk of high split proinsulin concentration, although it had no effect on the other cardio-metabolic markers in the offspring. At postnatal period breastfeeding proved to entail benefits in cardio-metabolic programming. Finally, the recommended dietary protein and total fat content in the child’s diet were important nutritional determinants reducing blood pressure at the age of four years. The intrauterine and immediate postnatal period comprise a window of opportunity for interventions aiming to reduce the risk of cardio-metabolic disorders and brings the prospect of achieving health benefits over one generation.

Tool-supported invariant-based programming

The development of correct programs is a core problem in computer science. Although formal verification methods for establishing correctness with mathematical rigor are available, programmers often find these difficult to put into practice. One hurdle is deriving the loop invariants and proving that the code maintains them. So called correct-by-construction methods aim to alleviate this issue by integrating verification into the programming workflow. Invariant-based programming is a practical correct-by-construction method in which the programmer first establishes the invariant structure, and then incrementally extends the program in steps of adding code and proving after each addition that the code is consistent with the invariants. In this way, the program is kept internally consistent throughout its development, and the construction of the correctness arguments (proofs) becomes an integral part of the programming workflow. A characteristic of the approach is that programs are described as invariant diagrams, a graphical notation similar to the state charts familiar to programmers. Invariant-based programming is a new method that has not been evaluated in large scale studies yet. The most important prerequisite for feasibility on a larger scale is a high degree of automation. The goal of the Socos project has been to build tools to assist the construction and verification of programs using the method. This thesis describes the implementation and evaluation of a prototype tool in the context of the Socos project. The tool supports the drawing of the diagrams, automatic derivation and discharging of verification conditions, and interactive proofs. It is used to develop programs that are correct by construction. The tool consists of a diagrammatic environment connected to a verification condition generator and an existing state-of-the-art theorem prover. Its core is a semantics for translating diagrams into verification conditions, which are sent to the underlying theorem prover. We describe a concrete method for 1) deriving sufficient conditions for total correctness of an invariant diagram; 2) sending the conditions to the theorem prover for simplification; and 3) reporting the results of the simplification to the programmer in a way that is consistent with the invariantbased programming workflow and that allows errors in the program specification to be efficiently detected. The tool uses an efficient automatic proof strategy to prove as many conditions as possible automatically and lets the remaining conditions be proved interactively. The tool is based on the verification system PVS and i uses the SMT (Satisfiability Modulo Theories) solver Yices as a catch-all decision procedure. Conditions that were not discharged automatically may be proved interactively using the PVS proof assistant. The programming workflow is very similar to the process by which a mathematical theory is developed inside a computer supported theorem prover environment such as PVS. The programmer reduces a large verification problem with the aid of the tool into a set of smaller problems (lemmas), and he can substantially improve the degree of proof automation by developing specialized background theories and proof strategies to support the specification and verification of a specific class of programs. We demonstrate this workflow by describing in detail the construction of a verified sorting algorithm. Tool-supported verification often has little to no presence in computer science (CS) curricula. Furthermore, program verification is frequently introduced as an advanced and purely theoretical topic that is not connected to the workflow taught in the early and practically oriented programming courses. Our hypothesis is that verification could be introduced early in the CS education, and that verification tools could be used in the classroom to support the teaching of formal methods. A prototype of Socos has been used in a course at Åbo Akademi University targeted at first and second year undergraduate students. We evaluate the use of Socos in the course as part of a case study carried out in 2007.

Teaching mathematics and programming : new approaches with empirical evaluation

Programming and mathematics are core areas of computer science (CS) and consequently also important parts of CS education. Introductory instruction in these two topics is, however, not without problems. Studies show that CS students find programming difficult to learn and that teaching mathematical topics to CS novices is challenging. One reason for the latter is the disconnection between mathematics and programming found in many CS curricula, which results in students not seeing the relevance of the subject for their studies. In addition, reports indicate that students' mathematical capability and maturity levels are dropping. The challenges faced when teaching mathematics and programming at CS departments can also be traced back to gaps in students' prior education. In Finland the high school curriculum does not include CS as a subject; instead, focus is on learning to use the computer and its applications as tools. Similarly, many of the mathematics courses emphasize application of formulas, while logic, formalisms and proofs, which are important in CS, are avoided. Consequently, high school graduates are not well prepared for studies in CS. Motivated by these challenges, the goal of the present work is to describe new approaches to teaching mathematics and programming aimed at addressing these issues: Structured derivations is a logic-based approach to teaching mathematics, where formalisms and justifications are made explicit. The aim is to help students become better at communicating their reasoning using mathematical language and logical notation at the same time as they become more confident with formalisms. The Python programming language was originally designed with education in mind, and has a simple syntax compared to many other popular languages. The aim of using it in instruction is to address algorithms and their implementation in a way that allows focus to be put on learning algorithmic thinking and programming instead of on learning a complex syntax. Invariant based programming is a diagrammatic approach to developing programs that are correct by construction. The approach is based on elementary propositional and predicate logic, and makes explicit the underlying mathematical foundations of programming. The aim is also to show how mathematics in general, and logic in particular, can be used to create better programs.