User���s Guide to C2R: A Set of C Language Output Routines Compatible with the R Statistics Language

C2R is a collection of C routines for saving complex data structures into a file that can be read in the R statistics environment with a single command.1 C2R provides both the means to transfer data structures significantly more complex than simple tables, and an archive mechanism to store data for future reference. We developed this software because we write and run computationally intensive numerical models in Fortran, C++, and AD Model Builder. We then analyse results with R. We desired to automate data transfer to speed diagnostics during working-group meetings. We thus developed the C2R interface to write an R data object (of type list) to a plain-text file. The master list can contain any number of matrices, values, dataframes, vectors or lists, all of which can be read into R with a single call to the dget function. This allows easy transfer of structured data from compiled models to R. Having the capacity to transfer model data, metadata, and results has sharply reduced the time spent on diagnostics, and at the same time, our diagnostic capabilities have improved tremendously. The simplicity of this interface and the capabilities of R have enabled us to automate graph and table creation for formal reports. Finally, the persistent storage in files makes it easier to treat model results in analyses or meta-analyses devised months���or even years���later. We offer C2R to others in the hope that they will find it useful. (PDF contains 27 pages)

RcppArmadillo : accelerating R with high-performance C++ linear algebra

The R statistical environment and language has demonstrated particular strengths for interactive development of statistical algorithms, as well as data modelling and visualisation. Its current implementation has an interpreter at its core which may result in a performance penalty in comparison to directly executing user algorithms in the native machine code of the host CPU. In contrast, the C++ language has no built-in visualisation capabilities, handling of linear algebra or even basic statistical algorithms; however, user programs are converted to high-performance machine code, ahead of execution. A new method avoids possible speed penalties in R by using the Rcpp extension package in conjunction with the Armadillo C++ matrix library. In addition to the inherent performance advantages of compiled code, Armadillo provides an easy-to-use template-based meta-programming framework, allowing the automatic pooling of several linear algebra operations into one, which in turn can lead to further speedups. With the aid of Rcpp and Armadillo, conversion of linear algebra centered algorithms from R to C++ becomes straightforward. The algorithms retains the overall structure as well as readability, all while maintaining a bidirectional link with the host R environment. Empirical timing comparisons of R and C++ implementations of a Kalman filtering algorithm indicate a speedup of several orders of magnitude.

The Credit Act Advisory System (CAAS) : conversion from an expert system prototype to a C++ commercial system

CAAS is a rule-based expert system, which provides advice on the Victorial Credit Act 1984. It is currently in commercial use, and has been developed in conjunction with a law firm. It uses an object-oriented hybrid reasoning approach. The system was initially prototyped using the expert system shell NExpert Object, and was then converted into the C++ language. In this paper we describe the advantages that this methodology has, for both commercial and research development.

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C programs for solving the time-dependent Gross-Pitaevskii equation in a fully anisotropic trap

Funda����o de Amparo �� Pesquisa do Estado de S��o Paulo (FAPESP)

Tool support for generating passive C++ test oracles from object-z specifications

A test oracle provides a means for determining whether an implementation behaves according to its specification. A passive test oracle checks that the correct behaviour has been implemented, but does not implement the behaviour itself. In previous work, we have presented a method that allows us to derive passive C++ test oracles from formal specifications written in Object-Z. We describe the "Warlock" prototype tool that supports the method. Warlock is built on top of an existing Object-Z type checker and generates oracle code for a substantial subset of the Object-Z language. We describe the architecture of Warlock and its application to a number of Object-Z specifications. We also discuss its current limitations.

Elliptic curves, group law, and efficient computation

This thesis is about the derivation of the addition law on an arbitrary elliptic curve and efficiently adding points on this elliptic curve using the derived addition law. The outcomes of this research guarantee practical speedups in higher level operations which depend on point additions. In particular, the contributions immediately find applications in cryptology. Mastered by the 19th century mathematicians, the study of the theory of elliptic curves has been active for decades. Elliptic curves over finite fields made their way into public key cryptography in late 1980���s with independent proposals by Miller [Mil86] and Koblitz [Kob87]. Elliptic Curve Cryptography (ECC), following Miller���s and Koblitz���s proposals, employs the group of rational points on an elliptic curve in building discrete logarithm based public key cryptosystems. Starting from late 1990���s, the emergence of the ECC market has boosted the research in computational aspects of elliptic curves. This thesis falls into this same area of research where the main aim is to speed up the additions of rational points on an arbitrary elliptic curve (over a field of large characteristic). The outcomes of this work can be used to speed up applications which are based on elliptic curves, including cryptographic applications in ECC. The aforementioned goals of this thesis are achieved in five main steps. As the first step, this thesis brings together several algebraic tools in order to derive the unique group law of an elliptic curve. This step also includes an investigation of recent computer algebra packages relating to their capabilities. Although the group law is unique, its evaluation can be performed using abundant (in fact infinitely many) formulae. As the second step, this thesis progresses the finding of the best formulae for efficient addition of points. In the third step, the group law is stated explicitly by handling all possible summands. The fourth step presents the algorithms to be used for efficient point additions. In the fifth and final step, optimized software implementations of the proposed algorithms are presented in order to show that theoretical speedups of step four can be practically obtained. In each of the five steps, this thesis focuses on five forms of elliptic curves over finite fields of large characteristic. A list of these forms and their defining equations are given as follows: (a) Short Weierstrass form, y2 = x3 + ax + b, (b) Extended Jacobi quartic form, y2 = dx4 + 2ax2 + 1, (c) Twisted Hessian form, ax3 + y3 + 1 = dxy, (d) Twisted Edwards form, ax2 + y2 = 1 + dx2y2, (e) Twisted Jacobi intersection form, bs2 + c2 = 1, as2 + d2 = 1, These forms are the most promising candidates for efficient computations and thus considered in this work. Nevertheless, the methods employed in this thesis are capable of handling arbitrary elliptic curves. From a high level point of view, the following outcomes are achieved in this thesis. - Related literature results are brought together and further revisited. For most of the cases several missed formulae, algorithms, and efficient point representations are discovered. - Analogies are made among all studied forms. For instance, it is shown that two sets of affine addition formulae are sufficient to cover all possible affine inputs as long as the output is also an affine point in any of these forms. In the literature, many special cases, especially interactions with points at infinity were omitted from discussion. This thesis handles all of the possibilities. - Several new point doubling/addition formulae and algorithms are introduced, which are more efficient than the existing alternatives in the literature. Most notably, the speed of extended Jacobi quartic, twisted Edwards, and Jacobi intersection forms are improved. New unified addition formulae are proposed for short Weierstrass form. New coordinate systems are studied for the first time. - An optimized implementation is developed using a combination of generic x86-64 assembly instructions and the plain C language. The practical advantages of the proposed algorithms are supported by computer experiments. - All formulae, presented in the body of this thesis, are checked for correctness using computer algebra scripts together with details on register allocations.

Scheduling techniques to optimise rail operations

In Australia, railway systems play a vital role in transporting the sugarcane crop from farms to mills. The sugarcane transport system is very complex and uses daily schedules, consisting of a set of locomotives runs, to satisfy the requirements of the mill and harvesters. The total cost of sugarcane transport operations is very high; over 35% of the total cost of sugarcane production in Australia is incurred in cane transport. Efficient schedules for sugarcane transport can reduce the cost and limit the negative effects that this system can have on the raw sugar production system. There are several benefits to formulating the train scheduling problem as a blocking parallel-machine job shop scheduling (BPMJSS) problem, namely to prevent two trains passing in one section at the same time; to keep the train activities (operations) in sequence during each run (trip) by applying precedence constraints; to pass the trains on one section in the correct order (priorities of passing trains) by applying disjunctive constraints; and, to ease passing trains by solving rail conflicts by applying blocking constraints and Parallel Machine Scheduling. Therefore, the sugarcane rail operations are formulated as BPMJSS problem. A mixed integer programming and constraint programming approaches are used to describe the BPMJSS problem. The model is solved by the integration of constraint programming, mixed integer programming and search techniques. The optimality performance is tested by Optimization Programming Language (OPL) and CPLEX software on small and large size instances based on specific criteria. A real life problem is used to verify and validate the approach. Constructive heuristics and new metaheuristics including simulated annealing and tabu search are proposed to solve this complex and NP-hard scheduling problem and produce a more efficient scheduling system. Innovative hybrid and hyper metaheuristic techniques are developed and coded using C# language to improve the solutions quality and CPU time. Hybrid techniques depend on integrating heuristic and metaheuristic techniques consecutively, while hyper techniques are the complete integration between different metaheuristic techniques, heuristic techniques, or both.

Child-related factors that influence teacher-child relationships using an Australian national sample

This study assessed the extent to which child-related factors had an impact on teacher-child relationships in Australian childcare settings. Analyses used data from Growing Up in Australia: The Longitudinal Study of Australian Children (LSAC). The sample consisted of 1577 two to three year old children (M= 33.9 months, SD=2.93; 51.5% male). Two separate hierarchical multiple regression analyses were conducted to examine the relation between teachers��� perceptions of their relationships with children and (a) gender, (b), indigenous status, (c), language background other than English, (d), socio-economic position, (e) special health care needs, (f) expression and receptive language concerns, (g) psychosocial competence and problems and (h) temperament factors (approach, persistence and reactivity). Results indicated that special health care needs, receptive language concerns and all three temperament scales (approach, persistence and reactivity) significantly predicted conflict in teacher-child relationships. Close relationships were predicted by being female, indigenous status, higher socio-economic position, not having a special health care need and no expressive language concerns.

A mobilidade eletrofor��tica e o perfil de potencial da membrana celular

O objetivo do presente trabalho foi estudar o comportamento dos potenciais superficiais e do perfil de potencial atraves da membrana de eritr ocito em func ao da forca i onica e das cargas superficiais, usando um modelo que leva em conta as cargas el etricas do glicoc alix e das proteınas citoplasm aticas, al em das cargas superficiais da bicamada lipıdica e os efeitos dos eletr olitos divalentes. Programas especıficos em linguagem C foram elaborados para o c alculo desses potenciais, tomando como dados num ericos resultados experimentais de medidas de mobilidade eletrofor etica de eritr ocitos para diferentes valores de forca i onica. Neste c alculo, o metodo para tratamento dos dados eletrofor eticos indicado por Hsu et al.[57] foi incluıdo em nosso modelo. A equac ao de Poisson-Boltzmann nao linear foi resolvida por computac ao num erica, usando o metodo de Runge-Kutta de quarta ordem, obtendo-se os perfis de potencial. Os resultados mostraram que a estimativa da densidade de carga el etrica na superfıcie de c elulas usando a equac ao cl assica de Helmholtz-Smoluchowski conduz a valores que nao conseguem refletir as forcas que regem o comportamento eletrofor etico das mesmas. O presente modelo gerou valores de potenciais superficiais e perfis de potencial para a membrana do eritr ocito bem distintos daqueles obtidos anteriormente para um modelo descrito por uma equac ao de Poisson-Boltzmann linear. Nossos resultados confirmam que a avaliac ao de parametros el etricos superficiais da membrana de eritr ocito, envolvendo dados oriundos de eletroforese, deve incluir c alculos hidrodin amicos al em de eletroest aticos, como sugerido por Hsu et al. [57].

Control de vuelo de un cuadric��ptero AR-Drone

[ES]En este TFG se obtendr�� un algoritmo de generaci��n de trayectorias para el cuadric��ptero AR-Drone capaz de conseguir trazados lo m��s r��pidos posibles teniendo en cuenta la din��mica del modelo y las limitaciones del entorno. As�� mismo se propondr�� un control primitivo para la detecci��n de obst��culos. Mediante las comunicaciones con el cuadric��ptero y el control de los par��metros caracter��sticos del medio, se establecer�� usando el lenguaje C# los bucles de programaci��n necesarios para discriminar todas las trayectorias desfavorables y obtener una que se adecue a nuestros criterios.

Implementa����o paralela do algoritmo iterativo de busca do par��metro de regulariza����o ��timo para o funcional de Tikhonov no problema de restaura����o de imagens

O uso de t��cnicas com o funcional de Tikhonov em processamento de imagens tem sido amplamente usado nos ��ltimos anos. A ideia b��sica nesse processo �� modificar uma imagem inicial via equa����o de convolu����o e encontrar um par��metro que minimize esse funcional afim de obter uma aproxima����o da imagem original. Por��m, um problema t��pico neste m��todo consiste na sele����o do par��metro de regulariza����o adequado para o compromisso entre a acur��cia e a estabilidade da solu����o. Um m��todo desenvolvido por pesquisadores do IPRJ e UFRJ, atuantes na ��rea de problemas inversos, consiste em minimizar um funcional de res��duos atrav��s do par��metro de regulariza����o de Tikhonov. Uma estrat��gia que emprega a busca iterativa deste par��metro visando obter um valor m��nimo para o funcional na itera����o seguinte foi adotada recentemente em um algoritmo serial de restaura����o. Por��m, o custo computacional �� um fator problema encontrado ao empregar o m��todo iterativo de busca. Com esta abordagem, neste trabalho �� feita uma implementa����o em linguagem C++ que emprega t��cnicas de computa����o paralela usando MPI (Message Passing Interface) para a estrat��gia de minimiza����o do funcional com o m��todo de busca iterativa, reduzindo assim, o tempo de execu����o requerido pelo algoritmo. Uma vers��o modificada do m��todo de Jacobi �� considerada em duas vers��es do algoritmo, uma serial e outra em paralelo. Este algoritmo �� adequado para implementa����o paralela por n��o possuir depend��ncias de dados como de Gauss-Seidel que tamb��m �� mostrado a convergir. Como indicador de desempenho para avalia����o do algoritmo de restaura����o, al��m das medidas tradicionais, uma nova m��trica que se baseia em crit��rios subjetivos denominada IWMSE (Information Weighted Mean Square Error) �� empregada. Essas m��tricas foram introduzidas no programa serial de processamento de imagens e permitem fazer a an��lise da restaura����o a cada passo de itera����o. Os resultados obtidos atrav��s das duas vers��es possibilitou verificar a acelera����o e a efici��ncia da implementa����o paralela. A m��todo de paralelismo apresentou resultados satisfat��rios em um menor tempo de processamento e com desempenho aceit��vel.

Otimiza����o do problema de localiza����o de instala����es aplicado ao com��rcio e distribui����o de combust��veis

Um dos problemas mais relevantes em organiza����es de grande porte �� a escolha de locais para instala����o de plantas industriais, centros de distribui����o ou mesmo pontos comerciais. Esse problema log��stico �� uma decis��o estrat��gica que pode causar um impacto significativo no custo total do produto comercializado. Existem na literatura diversos trabalhos que abordam esse problema. Assim, o objetivo desse trabalho �� analisar o problema da localiza����o de instala����es proposto por diferentes autores e definir um modelo que seja o mais adequado poss��vel ao mercado de distribui����o de combust��veis no Brasil. Para isso, foi realizada uma an��lise do fluxo de refino e distribui����o praticado neste segmento e da forma����o do respectivo custo de transporte. Foram consideradas restri����es como capacidade de estoque, gama de produtos ofertados e n��veis da hierarquia de distribui����o. A partir dessa an��lise, foi definido um modelo matem��tico aplicado �� redu����o dos custos de frete considerando-se a carga tribut��ria. O modelo matem��tico foi implementado, em linguagem C, e permite simular o problema. Foram aplicadas t��cnicas de computa����o paralela visando reduzir o tempo de execu����o do algoritmo. Os resultados obtidos com o modelo Single Uncapacited Facility Location Problem (SUFLP) simulado nas duas vers��es do programa, sequencial e paralela, demonstram ganhos de at�� 5% em economia de custos e redu����o do tempo de execu����o em mais de 50%.

Development of multi-channel gated integrator and PXI-DAQ system for nuclear detector arrays

A multi-channel gated integrator and PXI based data acquisition system have been developed for nuclear detector arrays with hundreds of detector units. The multi-channel gated integrator can be controlled by a programmable Cl controller. The PXI-DAQ system consists of NI PXI-1033 chassis with several PXI-DAQ cards. The system software has a user-friendly GUI which is written in C language using LabWindows/CVI under Windows XP operating system. The performance of the PXI-DAQ system is very reliable and capable of handling event rate up to 40 kHz. (C) 2010 Elsevier B.V. All rights reserved.