EGCL: an extended G-Code Language with flow control, functions and mnemonic variables

In the context of computer numerical control (CNC) and computer aided manufacturing (CAM), the capabilities of programming languages such as symbolic and intuitive programming, program portability and geometrical portfolio have special importance -- They allow to save time and to avoid errors during part programming and permit code re-usage -- Our updated literature review indicates that the current state of art presents voids in parametric programming, program portability and programming flexibility -- In response to this situation, this article presents a compiler implementation for EGCL (Extended G-code Language), a new, enriched CNC programming language which allows the use of descriptive variable names, geometrical functions and flow-control statements (if-then-else, while) -- Our compiler produces low-level generic, elementary ISO-compliant Gcode, thus allowing for flexibility in the choice of the executing CNC machine and in portability -- Our results show that readable variable names and flow control statements allow a simplified and intuitive part programming and permit re-usage of the programs -- Future work includes allowing the programmer to define own functions in terms of EGCL, in contrast to the current status of having them as library built-in functions

An��lise gr��fica de estruturas porosas sobre a ��tica da estereologia

In this work we developed a computer simulation program for physics porous structures based on programming language C + + using a Geforce 9600 GT with the PhysX chip, originally developed for video games. With this tool, the ability of physical interaction between simulated objects is enlarged, allowing to simulate a porous structure, for example, reservoir rocks and structures with high density. The initial procedure for developing the simulation is the construction of porous cubic structure consisting of spheres with a single size and with varying sizes. In addition, structures can also be simulated with various volume fractions. The results presented are divided into two parts: first, the ball shall be deemed as solid grains, ie the matrix phase represents the porosity, the second, the spheres are considered as pores. In this case the matrix phase represents the solid phase. The simulations in both cases are the same, but the simulated structures are intrinsically different. To validate the results presented by the program, simulations were performed by varying the amount of grain, the grain size distribution and void fraction in the structure. All results showed statistically reliable and consistent with those presented in the literature. The mean values and distributions of stereological parameters measured, such as intercept linear section of perimeter area, sectional area and mean free path are in agreement with the results obtained in the literature for the structures simulated. The results may help the understanding of real structures.

Tighter, Neater, Safer C and C++

Report published in the Proceedings of the National Conference on "Education and Research in the Information Society", Plovdiv, May, 2016

Code pattern analysis of object-oriented programming languages

Code patterns, including programming patterns and design patterns, are good references for programming language feature improvement and software re-engineering. However, to our knowledge, no existing research has attempted to detect code patterns based on code clone detection technology. In this study, we build upon the previous work and propose to detect and analyze code patterns from a collection of open source projects using NiPAT technology. Because design patterns are most closely associated with object-oriented languages, we choose Java and Python projects to conduct our study. The tool we use for detecting patterns is NiPAT, a pattern detecting tool originally developed for the TXL programming language based on the NiCad clone detector. We extend NiPAT for the Java and Python programming languages. Then, we try to identify all the patterns from the pattern report and classify them into several different categories. In the end of the study, we analyze all the patterns and compare the differences between Java and Python patterns.

Refining specifications to logic programs

The refinement calculus provides a framework for the stepwise development of imperative programs from specifications. In this paper we study a refinement calculus for deriving logic programs. Dealing with logic programs rather than imperative programs has the dual advantages that, due to the expressive power of logic programs, the final program is closer to the original specification, and each refinement step can achieve more. Together these reduce the overall number of derivation steps. We present a logic programming language extended with specification constructs (including general predicates, assertions, and types and invariants) to form a wide-spectrum language. General predicates allow non-executable properties to be included in specifications. Assertions, types and invariants make assumptions about the intended inputs of a procedure explicit, and can be used during refinement to optimize the constructed logic program. We provide a semantics for the extended logic programming language and derive a set of refinement laws. Finally we apply these to an example derivation.

A refinement calculus for logic programs

Existing refinement calculi provide frameworks for the stepwise development of imperative programs from specifications. This paper presents a refinement calculus for deriving logic programs. The calculus contains a wide-spectrum logic programming language, including executable constructs such as sequential conjunction, disjunction, and existential quantification, as well as specification constructs such as general predicates, assumptions and universal quantification. A declarative semantics is defined for this wide-spectrum language based on executions. Executions are partial functions from states to states, where a state is represented as a set of bindings. The semantics is used to define the meaning of programs and specifications, including parameters and recursion. To complete the calculus, a notion of correctness-preserving refinement over programs in the wide-spectrum language is defined and refinement laws for developing programs are introduced. The refinement calculus is illustrated using example derivations and prototype tool support is discussed.

Agents as multi-threaded logical objects

In this paper we describe a distributed object oriented logic programming language in which an object is a collection of threads deductively accessing and updating a shared logic program. The key features of the language, such as static and dynamic object methods and multiple inheritance, are illustrated through a series of small examples. We show how we can implement object servers, allowing remote spawning of objects, which we can use as staging posts for mobile agents. We give as an example an information gathering mobile agent that can be queried about the information it has so far gathered whilst it is gathering new information. Finally we define a class of co-operative reasoning agents that can do resource bounded inference for full first order predicate logic, handling multiple queries and information updates concurrently. We believe that the combination of the concurrent OO and the LP programming paradigms produces a powerful tool for quickly implementing rational multi-agent applications on the internet.

An SPSS R-Menu for Ordinal Factor Analysis

Exploratory factor analysis is a widely used statistical technique in the social sciences. It attempts to identify underlying factors that explain the pattern of correlations within a set of observed variables. A statistical software package is needed to perform the calcula- tions. However, there are some limitations with popular statistical software packages, like SPSS. The R programming language is a free software package for statistical and graphical computing. It o ers many packages written by contributors from all over the world and programming resources that allow it to overcome the dialog limitations of SPSS. This paper o ers an SPSS dialog written in the R programming language with the help of some packages, so that researchers with little or no knowledge in programming, or those who are accustomed to making their calculations based on statistical dialogs, have more options when applying factor analysis to their data and hence can adopt a better approach when dealing with ordinal, Likert-type data.

Analisador de vibra����es de dois canais baseado em computador

O presente trabalho teve como principal objectivo o desenvolvimento de um analisador de vibra����es de dois canais baseado em computador, para a realiza����o de diagn��stico no ��mbito do controlo de condi����o de m��quinas. Foi desenvolvida uma aplica����o num computador comum, no software LabVIEW, que atrav��s de transdutores de acelera����o do tipo MEMS conectados via USB, faz a recolha de dados de vibra����o e procede ao seu processamento e apresenta����o ao utilizador. As ferramentas utilizadas para o processamento de dados s��o ferramentas comuns encontradas em v��rios analisadores de vibra����es dispon��veis no mercado. Estas podem ser: gr��ficos de espectro de frequ��ncia, sinal no tempo, cascata ou valores de n��vel global de vibra����o, entre outras. Apesar do analisador desenvolvido n��o apresentar inova����o nas ferramentas de an��lise adoptadas, este pretende ser distinguido pelo baixo custo, simplicidade e car��cter did��ctico. Este trabalho vem evidenciar as vantagens, desvantagens e potencialidades de um analisador desta natureza. S��o tiradas algumas conclus��es quanto �� sua capacidade de diagn��stico de avarias, capacidades como ferramenta did��ctica, sensores utilizados e linguagem de programa����o escolhida. Como conclus��es principais, o trabalho revela que os sensores escolhidos n��o s��o os indicados para efectuar o diagn��stico de avarias em ambiente industrial, contudo s��o ideais para tornar este analisador numa boa ferramenta did��ctica e de treino.

Processing XML with Java ��� a performance benchmark

Over time, XML markup language has acquired a considerable importance in applications development, standards definition and in the representation of large volumes of data, such as databases. Today, processing XML documents in a short period of time is a critical activity in a large range of applications, which imposes choosing the most appropriate mechanism to parse XML documents quickly and efficiently. When using a programming language for XML processing, such as Java, it becomes necessary to use effective mechanisms, e.g. APIs, which allow reading and processing of large documents in appropriated manners. This paper presents a performance study of the main existing Java APIs that deal with XML documents, in order to identify the most suitable one for processing large XML files

Performance analysis of Java APIS for XML processing

Over time, XML markup language has acquired a considerable importance in applications development, standards definition and in the representation of large volumes of data, such as databases. Today, processing XML documents in a short period of time is a critical activity in a large range of applications, which imposes choosing the most appropriate mechanism to parse XML documents quickly and efficiently. When using a programming language for XML processing, such as Java, it becomes necessary to use effective mechanisms, e.g. APIs, which allow reading and processing of large documents in appropriated manners. This paper presents a performance study of the main existing Java APIs that deal with XML documents, in order to identify the most suitable one for processing large XML files.

Group decision making and Quality-of-information in e-Health systems

Knowledge is central to the modern economy and society. Indeed, the knowledge society has transformed the concept of knowledge and is more and more aware of the need to overcome the lack of knowledge when has to make options or address its problems and dilemmas. One���s knowledge is less based on exact facts and more on hypotheses, perceptions or indications. Even when we use new computational artefacts and novel methodologies for problem solving, like the use of Group Decision Support Systems (GDSSs), the question of incomplete information is in most of the situations marginalized. On the other hand, common sense tells us that when a decision is made it is impossible to have a perception of all the information involved and the nature of its intrinsic quality. Therefore, something has to be made in terms of the information available and the process of its evaluation. It is under this framework that a Multi-valued Extended Logic Programming language will be used for knowledge representation and reasoning, leading to a model that embodies the Quality-of-Information (QoI) and its quantification, along the several stages of the decision-making process. In this way, it is possible to provide a measure of the value of the QoI that supports the decision itself. This model will be here presented in the context of a GDSS for VirtualECare, a system aimed at sustaining online healthcare services.

Modelo SIG para apoio �� an��lise de sistemas de transportes e usos do solo

Disserta����o de natureza cient��fica para obten����o do grau de Mestre em Engenharia Civil

Constru����o de interfaces em Flex para sistemas de experimenta����o remota

Os laborat��rios de experimenta����o remota est��o normalmente associados a tecnologias ou solu����es propriet��rias, as quais restringem a sua utiliza����o a determinadas plataformas e obrigam ao uso de software espec��fico no lado do cliente. O ISEP possui um laborat��rio de experimenta����o remota, baseado em instrumenta����o virtual, usado no apoio ao ensino da electr��nica e constru��do sobre uma plataforma NIELVIS da National Instruments. O software de controlo da plataforma recorre �� linguagem gr��fica de programa����o LabVIEW. Esta �� uma ferramenta desenvolvida pela National Instruments que facilita o desenvolvimento de aplica����es de sistemas de experimenta����o remota, mas que possui v��rias limita����es, nomeadamente a necessidade de instala����o do lado do cliente de um plug-in, cuja disponibilidade se encontra limitada a determinadas vers��es de sistemas operativos e de Web Browsers. A experi��ncia anterior demonstrou que estas quest��es limitam o n��mero de clientes com possibilidade de acesso ao laborat��rio remoto, para al��m de, em alguns casos, se ter verificado n��o ser transparente a sua instala����o e utiliza����o. Neste contexto, o trabalho de investiga����o consistiu no desenvolvimento de uma solu����o que permite a gera����o de interfaces que possibilitam o controlo remoto do sistema implementado, e que, ao mesmo tempo, s��o independentes da plataforma usada pelo cliente.

Suporte �� computa����o paralela e distribu��da em Java: API e comunica����o entre n��s cooperantes

Este trabalho �� uma parte do tema global ���Suporte �� Computa����o Paralela e Distribu��da em Java���, tamb��m tema da tese de Daniel Barciela no mestrado de Engenharia Inform��tica do Instituto Superior de Engenharia do Porto. O seu objetivo principal consiste na defini����o/cria����o da interface com o programador, assim como tamb��m abrange a forma como os n��s comunicam e cooperam entre si para a execu����o de determinadas tarefas, de modo a atingirem um ��nico objetivo global. No ��mbito desta disserta����o foi realizado um estudo pr��vio relativamente aos modelos te��ricos referentes �� computa����o paralela, assim como tamb��m foram analisadas linguagens e frameworks que fornecem suporte a este mesmo tipo de computa����o. Este estudo teve como principal objetivo a an��lise da forma como estes modelos e linguagens permitem ao programador expressar o processamento paralelo no desenvolvimento das aplica����es. Como resultado desta disserta����o surgiu a framework denominada Distributed Parallel Framework for Java (DPF4j), cujo objetivo principal �� fornecer aos programadores o suporte para o desenvolvimento de aplica����es paralelas e distribu��das. Esta framework foi desenvolvida na linguagem Java. Esta disserta����o contempla a parte referente �� interface de programa����o e a toda a comunica����o entre n��s cooperantes da framework DPF4j. Por fim, foi demonstrado atrav��s dos testes realizados que a DPF4j, apesar de ser ainda um prot��tipo, j�� demonstra ter uma performance superior a outras frameworks e linguagens que possuem os mesmos objetivos.