Contract-Based General-Purpose GPU Programming

Using GPUs as general-purpose processors has revolutionized parallel computing by offering, for a large and growing set of algorithms, massive data-parallelization on desktop machines. An obstacle to widespread adoption, however, is the difficulty of programming them and the low-level control of the hardware required to achieve good performance. This paper suggests a programming library, SafeGPU, that aims at striking a balance between programmer productivity and performance, by making GPU data-parallel operations accessible from within a classical object-oriented programming language. The solution is integrated with the design-by-contract approach, which increases confidence in functional program correctness by embedding executable program specifications into the program text. We show that our library leads to modular and maintainable code that is accessible to GPGPU non-experts, while providing performance that is comparable with hand-written CUDA code. Furthermore, runtime contract checking turns out to be feasible, as the contracts can be executed on the GPU

Multidomain Simulation Model for Analysis of Geometric Variation and Productivity in Multi-Stage Assembly Systems

Nowadays, the new era of industry 4.0 is forcing manufacturers to develop models and methods for managing the geometric variation of a final product in complex manufacturing environments, such as multistage manufacturing systems. The stream of variation model has been successfully applied to manage product geometric variation in these systems, but there is a lack of research studying its application together with the material and order flow in the system. In this work, which is focused on the production quality paradigm in a model-based system engineering context, a digital prototype is proposed to integrate productivity and part quality based on the stream of variation analysis in multistage assembly systems. The prototype was modelled and simulated with OpenModelica tool exploiting the Modelica language capabilities for multidomain simulations and its synergy with SysML. A case study is presented to validate the potential applicability of the approach. The proposed model and the results show a promising potential for future developments aligned with the production quality paradigm

Status of the differential transformation method

Further to a recent controversy on whether the differential transformation method (DTM) for solving a differential equation is purely and solely the traditional Taylor series method, it is emphasized that the DTM is currently used, often only, as a technique for (analytically) calculating the power series of the solution (in terms of the initial value parameters). Sometimes, a piecewise analytic continuation process is implemented either in a numerical routine (e.g., within a shooting method) or in a semi-analytical procedure (e.g., to solve a boundary value problem). Emphasized also is the fact that, at the time of its invention, the currently-used basic ingredients of the DTM (that transform a differential equation into a difference equation of same order that is iteratively solvable) were already known for a long time by the "traditional"-Taylor-method users (notably in the elaboration of software packages --numerical routines-- for automatically solving ordinary differential equations). At now, the defenders of the DTM still ignore the, though much better developed, studies of the "traditional"-Taylor-method users who, in turn, seem to ignore similarly the existence of the DTM. The DTM has been given an apparent strong formalization (set on the same footing as the Fourier, Laplace or Mellin transformations). Though often used trivially, it is easily attainable and easily adaptable to different kinds of differentiation procedures. That has made it very attractive. Hence applications to various problems of the Taylor method, and more generally of the power series method (including noninteger powers) has been sketched. It seems that its potential has not been exploited as it could be. After a discussion on the reasons of the "misunderstandings" which have caused the controversy, the preceding topics are concretely illustrated.Comment: To appear in Applied Mathematics and Computation, 29 pages, references and further considerations adde

Systolic array synthesis by static analysis of program dependencies

Journal ArticleWe present a technique for mapping recurrence equations to systolic arrays. While this problem has been studied in fairly great detail, the recurrence equations that are analysed here are a generalization of those studied previously. In a n earlier paper (14] we have showed how systolic arrays can be synthesized from such generalized recurrence equations by a combination of affine transformations and explicit pipelining. This paper extends the results in two directions. Firstly, a multistage pipelining technique is proposed, which permits the synthesis of systolic arrays with irregular data flow. Secondly we develop analysis techniques for the synthesis of systolic arrays whose computation is governed by control signals in a systematic manner which is amenable to mechanization. The full paper also discusses how these techniques can be applied to the mapping problem for more general architectures

Probabilistic structural mechanics research for parallel processing computers

Aerospace structures and spacecraft are a complex assemblage of structural components that are subjected to a variety of complex, cyclic, and transient loading conditions. Significant modeling uncertainties are present in these structures, in addition to the inherent randomness of material properties and loads. To properly account for these uncertainties in evaluating and assessing the reliability of these components and structures, probabilistic structural mechanics (PSM) procedures must be used. Much research has focused on basic theory development and the development of approximate analytic solution methods in random vibrations and structural reliability. Practical application of PSM methods was hampered by their computationally intense nature. Solution of PSM problems requires repeated analyses of structures that are often large, and exhibit nonlinear and/or dynamic response behavior. These methods are all inherently parallel and ideally suited to implementation on parallel processing computers. New hardware architectures and innovative control software and solution methodologies are needed to make solution of large scale PSM problems practical

Refinement and variability techniques in model transformation of software requirements

Tese de Doutoramento em Tecnologias e Sistemas de InformaçãoThis thesis begins with analyzing user functional requirements (as use cases) from the perspective of detail. In that sense, it investigates the applicability of the UML (Unified Modeling Language) «include» relationship to the representation of use case refinement and proposes another relationship for that purpose. It also clarifies the process of modeling use cases with UML when refinement is involved and provides for some guidelines in order to conduct that process. Afterwards, the work of this thesis on use case modeling is expanded to the field of SPLs (Software Product Lines) by means of exploring the UML «extend» relationship. It talks about alternative, specialization and option use cases as the representation of the three variability types this thesis proposes to be translated into stereotypes to mark use cases. Then, this thesis incorporates the refinement of logical architectures with variability support from use cases also with variability support in the 4SRS (Four Step Rule Set) transition method for model transformation of analysis artifacts (use cases) into design artifacts (logical architectures represented as UML component diagrams). The model transformation the 4SRS guides in a stepwise way, from use cases into logical architectures, is based on a software development pattern that addresses architecture. This thesis yields a multilevel and multistage pattern classification that grounds the use of that pattern to generate system functional requirements (as logical architectures). Lastly, the 4SRS transition method is modeled with the SPEM (Software & Systems Process Engineering Metamodel) and formalized as a small software development process dedicated at transitioning from the analysis to the design of software. After that, this thesis presents a case study on the automation of the 4SRS and thoroughly elaborates on the transformation rules that support the model transformations of the 4SRS.Esta tese começa por analisar requisitos funcionais de utilizador (enquanto casos de utilização) sob a perspectiva do detalhe. Nesse sentido, esta tese investiga a aplicabilidade da relação UML (Unified Modeling Language) «include» para a representação do refinamento de casos de utilização e propõe outra relação para esse fim. Esta tese também clarifica o processo de modelação de casos de utilização com a UML quando esse processo envolve refinamento e fornece algumas diretrizes para a condução desse processo. De seguida, o trabalho desta tese em modelação de casos de utilização é expandido para o campo das linhas de produtos de software através da exploração da relação UML «extend». Esse trabalho fala de casos de utilização alternativos, de especialização e opcionais como a representação dos três tipos de variabilidade que esta tese propõe que sejam traduzidos em estereótipos para a marcação de casos de utilização. Depois, esta tese incorpora o refinamento de arquitecturas lógicas com suporte à variabilidade a partir de casos de utilização também com suporte à variabilidade no método de transição 4SRS (Four Step Rule Set) para a tranformação de modelos de artefatos de análise (casos de utilização) em modelos de artefatos de design (arquitecturas lógicas representadas como diagramas de components UML). A transformação de modelos que o 4SRS guia por passos, de casos de utilização em arquitecturas lógicas, baseia-se num padrão de desenvolvimento de software que visa arquitetura. Esta tese produz uma classificação multinível e multietapa de padrões, que sustenta a utilização desse padrão na geração de requisitos funcionais de sistema (enquanto arquitecturas lógicas). Por fim, o método de transição 4SRS é modelado com o SPEM (Software & Systems Process Engineering Metamodel) e formalizado como um pequeno processo de desenvolvimento de software dedicado a transitar da análise para o design the software. Depois disso, esta tese apresenta um estudo de caso sobre a automatização do 4SRS e elabora minuciosamente acerca das regras de transformação que apoiam as transformações de modelos do 4SRS

Development framework pattern for pervasive information systems

During last decade, the world watched a social acceptance of computing and computers, enhanced information technology devices, wireless networks, and Internet; they gradually became a fundamental resource for individuals. Nowadays, people, organizations, and the environment are empowered by computing devices and systems; they depend on services offered by modern Pervasive Information Systems supported by complex software systems and technology. Research on software development for PIS-delivered information, on issues and challenges on software development for them, and several other contributions have been delivered. Among these contributions are a development framework for PIS, a profiling and framing structure approach, and a SPEM 2.0 extension. This chapter, revisiting these contributions, provides an additional contribution: a pattern to support the use of the development framework and profiling approach on software development for PIS. This contribution completes a first series of contributions for the development of PIS. This chapter also presents a case study that allowed demonstrating the applicability of these contribution

Object approach computation by a giant neuron and its relation with the speed of escape in the crab Neohelice

Upon detection of an approaching object, the crab Neohelice granulata continuously regulates the direction and speed of escape according to ongoing visual information. These visuomotor transformations are thought to be largely accounted for by a small number of motion-sensitive giant neurons projecting from the lobula (third optic neuropil) towards the supraesophageal ganglion. One of these elements, the monostratified lobula giant neuron of type 2 (MLG2), proved to be highly sensitive to looming stimuli (a 2D representation of an object approach). By performing in vivo intracellular recordings, we assessed the response of the MLG2 neuron to a variety of looming stimuli representing objects of different sizes and velocities of approach. This allowed us to: (1) identify some of the physiological mechanisms involved in the regulation of the MLG2 activity and test a simplified biophysical model of its response to looming stimuli; (2) identify the stimulus optical parameters encoded by the MLG2 and formulate a phenomenological model able to predict the temporal course of the neural firing responses to all looming stimuli; and (3) incorporate the MLG2-encoded information of the stimulus (in terms of firing rate) into a mathematical model able to fit the speed of the escape run of the animal. The agreement between the model predictions and the actual escape speed measured on a treadmill for all tested stimuli strengthens our interpretation of the computations performed by the MLG2 and of the involvement of this neuron in the regulation of the animal's speed of run while escaping from objects approaching with constant speed.Fil: Oliva, Damian Ernesto. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Tomsic, Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Fisiología, Biología Molecular y Neurociencias. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Fisiología, Biología Molecular y Neurociencias; Argentin

Deep learning in medical image registration: introduction and survey

Image registration (IR) is a process that deforms images to align them with respect to a reference space, making it easier for medical practitioners to examine various medical images in a standardized reference frame, such as having the same rotation and scale. This document introduces image registration using a simple numeric example. It provides a definition of image registration along with a space-oriented symbolic representation. This review covers various aspects of image transformations, including affine, deformable, invertible, and bidirectional transformations, as well as medical image registration algorithms such as Voxelmorph, Demons, SyN, Iterative Closest Point, and SynthMorph. It also explores atlas-based registration and multistage image registration techniques, including coarse-fine and pyramid approaches. Furthermore, this survey paper discusses medical image registration taxonomies, datasets, evaluation measures, such as correlation-based metrics, segmentation-based metrics, processing time, and model size. It also explores applications in image-guided surgery, motion tracking, and tumor diagnosis. Finally, the document addresses future research directions, including the further development of transformers