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| 2. |
- Svensson, Bertil, 1948-, et al.
(författare)
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A running leap for embedded signal processing to future parallel platforms
- 2014
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Ingår i: WISE 2014 - Proceedings of the 2014 ACM International Workshop on Long-Term Industrial Collaboration on Software Engineering, Co-located with ASE 2014. - New York, NY, USA : Association for Computing Machinery, Inc. - 9781450330459 ; , s. 35-42
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Konferensbidrag (refereegranskat)abstract
- This paper highlights the collaboration between industry and academia in research. It describes more than two decades of intensive development and research of new hardware and software platforms to support innovative, high-performance sensor systems with extremely high demands on embedded signal processing capability. The joint research can be seen as the run before a necessary jump to a new kind of computational platform based on parallelism. The collaboration has had several phases, starting with a focus on hardware, then on efficiency, later on software development, and finally on taking the jump and understanding the expected future. In the first part of the paper, these phases and their respective challenges and results are described. Then, in the second part, we reflect upon the motivation for collaboration between company and university, the roles of the partners, the experiences gained and the long-term effects on both sides.
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| 3. |
- Essayas, Gebrewahid, 1984-, et al.
(författare)
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Realizing Efficient Execution of Dataflow Actors on Manycores
- 2014
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Ingår i: 2014 12th IEEE International Conference on Embedded and Ubiquitous Computing (EUC 2014). - Los Alamitos, CA : IEEE Computer Society. ; , s. 321-328, s. 321-328
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Konferensbidrag (refereegranskat)abstract
- Embedded DSP computing is currently shifting towards manycore architectures in order to cope with the ever growing computational demands. Actor based dataflow languages are being considered as a programming model. In this paper we present a code generator for CAL, one such dataflow language. We propose to use a compilation tool with two intermediate representations. We start from a machine model of the actors that provides an ordering for testing of conditions and firing of actions. We then generate an Action Execution Intermediate Representation that is closer to a sequential imperative language like C and Java. We describe our two intermediate representations and show the feasibility and portability of our approach by compiling a CAL implementation of the Two-Dimensional Inverse Discrete Cosine Transform on a general purpose processor, on the Epiphany manycore architecture and on the Ambric massively parallel processor array.
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| 4. |
- Gaspes, Verónica, 1963
(författare)
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A Type Theoretical Analysis of Some Aspects of Programming Languages
- 1997
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- We present three papers on the application of Martin-Löf's type theory to the analysis of programming languages. In the first paper, we present formal proofs in type theory of the combinatorial completeness of two calculi of combinators. The statement formulates the ability of the calculi to describe functions. The calculi we consider are that of untyped combinators and that of simply typed combinators. In the latter case the statement can be understood, through the Curry-Howard correspondence, as formulating the deductive completeness of the Hilbert style presentation of minimal logic. The formalization was carried out with the help of the proof editor Alf and is thus machine checked. The paper includes an appendix with an edited version of the implementation in Alf. In the second paper, we consider typed combinatory calculi and establish formally in type theory that all combinators have a normal form. Again the proofs were carried out with the help of Alf and thus machine checked. Both simply typed combinators and a combinator version of system T are considered. The proofs of normalization are then used to obtain an algorithm to compute normal forms. In the third paper, we present a formal version of the extension of type theory to include infinite objects as given by Per Martin-Löf. We also consider some programming examples and the relation of this extended theory to lazy functional languages. In carrying out the formal presentation, we made use of a presentation of type theory suitable for metamathematical studies which has been put forward by Per Martin-Löf. The monograph also includes a complete presentation of this.
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| 5. |
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| 6. |
- Gebrewahid, Essayas, 1984-, et al.
(författare)
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Cal2Many : A Framework to Compile Dataflow Programs for Manycores
- 2017
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- The arrival of manycore platforms has imposed programming challenges for mainstream embedded system developers. In this paper, we discuss the significance of actor-oriented dataflow languages and present our compilation framework for CAL Actor Language that leads to increased portability and retargetability. We demonstrate the applicability of our approach with streaming applications targeting the Epiphany many-core architecture. We have performed an in-depth analysis of MPEG-4 SP implemented on Epiphany using our framework and studied the effects of actor composition. We have identified hardware aspects such as increased off-chip memory bandwidth and larger local memories that could result in further performance improvements.
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| 7. |
- Gebrewahid, Essayas, 1984-, et al.
(författare)
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Programming Real-time Image Processing for Manycores in a High-level Language
- 2013
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Ingår i: Advanced Parallel Processing Technology. - Berlin Heidelberg : Springer Berlin/Heidelberg. - 9783642452925 ; , s. 381-395
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Konferensbidrag (refereegranskat)abstract
- Manycore architectures are gaining attention as a means to meet the performance and power demands of high-performance embedded systems. However, their widespread adoption is sometimes constrained by the need formastering proprietary programming languages that are low-level and hinder portability. We propose the use of the concurrent programming language occam-pi as a high-level language for programming an emerging class of manycore architectures. We show how to map occam-pi programs to the manycore architecture Platform 2012 (P2012). We describe the techniques used to translate the salient features of the language to the native programming model of the P2012. We present the results from a case study on a representative algorithm in the domain of real-time image processing: a complex algorithm for corner detectioncalled Features from Accelerated Segment Test (FAST). Our results show that the occam-pi program is much shorter, is easier to adapt and has a competitive performance when compared to versions programmed in the native programming model of P2012 and in OpenCL.
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| 8. |
- Gebrewahid, Essayas, 1984-
(författare)
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Tools to Compile Dataflow Programs for Manycores
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The arrival of manycore systems enforces new approaches for developing applications in order to exploit the available hardware resources. Developing applications for manycores requires programmers to partition the application into subtasks, consider the dependence between the subtasks, understand the underlying hardware and select an appropriate programming model. This is complex, time-consuming and prone to error. In this thesis, we identify and implement abstraction layers in compilation tools to decrease the burden of the programmer, increase program portability and scalability, and increase retargetability of the compilation framework. We present compilation frameworks for two concurrent programming languages, occam-pi and CAL Actor Language, and demonstrate the applicability of the approach with application case-studies targeting these different manycore architectures: STHorm, Epiphany, Ambric, EIT, and ePUMA. For occam-pi, we have extended the Tock compiler and added a backend for STHorm. We evaluate the approach using a fault tolerance model for a four stage 1D-DCT algorithm implemented by using occam-pi's constructs for dynamic reconguration, and the FAST corner detection algorithm which demonstrates the suitability of occam-pi and the compilation framework for data-intensive applications. For CAL, we have developed a new compilation framework, namely Cal2Many. The Cal2Many framework has a front end, two intermediate representations and four backends: for a uniprocessor, Epiphany, Ambric, and a backend for SIMD based architectures. Also, we have identied and implemented of CAL actor fusion and fission methodologies for efficient mapping CAL applications. We have used QRD, FAST corner detection, 2D-IDCT, and MPEG applications to evaluate our compilation process and to analyze the limitations of the hardware.
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| 9. |
- Taha, Walid, 1971-, et al.
(författare)
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A Core Language for Executable Models of Cyber-Physical Systems (Preliminary Report)
- 2012
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Konferensbidrag (refereegranskat)abstract
- Recently we showed that an expressive class of mathematical equations can be automatically translated into simulation codes. By focusing on the expressivity of equations formed from continuous functions, this work did not accommodate a wide range of discrete behaviors or a dynamic collection of components. However, the interaction between continuous and hybrid components in many cyber-physical domains is highly coupled, and such systems are often highly dynamic in both respects. This paper gives an overview of a proposed core language for capturing executable hybrid models of highly dynamic cyber-physical systems. © 2012 IEEE.
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| 10. |
- Taha, Walid, 1972-, et al.
(författare)
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Acumen : An Open-source Testbed for Cyber-Physical Systems Research
- 2016
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Ingår i: Internet of Things. IoT Infrastructures. - Heidelberg : Springer. - 9783319470627 - 9783319470634 ; , s. 118-130
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Konferensbidrag (refereegranskat)abstract
- Developing Cyber-Physical Systems requires methods and tools to support simulation and verification of hybrid (both continuous and discrete) models. The Acumen modeling and simulation language is an open source testbed for exploring the design space of what rigorous-but-practical next-generation tools can deliver to developers of Cyber-Physical Systems. Like verification tools, a design goal for Acumen is to provide rigorous results. Like simulation tools, it aims to be intuitive, practical, and scalable. However, it is far from evident whether these two goals can be achieved simultaneously.This paper explains the primary design goals for Acumen, the core challenges that must be addressed in order to achieve these goals, the "agile research method" taken by the project, the steps taken to realize these goals, the key lessons learned, and the emerging language design. © ICST Institute for Computer Sciences, Social Informatics and Telecommunications Engineering 2016.
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