| 41. |
- Krenz-Bååth, René, 1974-
(författare)
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Dominator-based Algorithms in Logic Synthesis and Verification
- 2007
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Today's EDA (Electronic Design Automation) industry faces enormous challenges. Their primary cause is the tremendous increase of the complexity of modern digital designs. Graph algorithms are widely applied to solve various EDA problems. In particular, graph dominators, which provide information about the origin and the end of reconverging paths in a circuit graph, proved to be useful in various CAD (Computer Aided Design) applications such as equivalence checking, ATPG, technology mapping, and power optimization. This thesis provides a study on graph dominators in logic synthesis and verification. The thesis contributes a set of algorithms for computing dominators in circuit graphs. An algorithm is proposed for finding absolute dominators in circuit graphs. The achieved speedup of three orders of magnitude on several designs enables the computation of absolute dominators in large industrial designs in a few seconds. Moreover, the computation of single-vertex dominators in large multiple-output circuit graphs is considerably improved. The proposed algorithm reduces the overall runtime by efficiently recognizing and re-using isomorphic structures in dominator trees rooted at different outputs of the circuit graph. Finally, common multiple-vertex dominators are introduced. The algorithm to compute them is faster and finds more multiple-vertex dominators than previous approaches. The thesis also proposes new dominator-based algorithms in the area of decomposition and combinational equivalence checking. A structural decomposition technique is introduced, which finds all simple-disjoint decompositions of a Boolean function which are reflected in the circuit graph. The experimental results demonstrate that the proposed technique outperforms state-of-the-art functional decomposition techniques. Finally, an approach to check the equivalence of two Boolean functions probabilistically is investigated. The proposed algorithm partitions the equivalence check employing dominators in the circuit graph. The experimental results confirm that, in comparison to traditional BDD-based equivalence checking methods, the memory consumption is considerably reduced by using the proposed technique.
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| 42. |
- Kumar, Shashi, et al.
(författare)
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A network on chip architecture and design methodology
- 2002
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Ingår i: VLSI 2002. - : IEEE conference proceedings. - 0769514863 ; , s. 105-112
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Konferensbidrag (refereegranskat)abstract
- We propose a packet switched platform for single chip systems which scales well to an arbitrary number of processor like resources. The platform, which we call Network-on-Chip (NOC), includes both the architecture and the design methodology. The NOC architecture is a m x n mesh of switches and resources are placed on the slots formed by the switches. We assume a direct layout of the 2-D mesh of switches and resources providing physical- architectural level design integration. Each switch is connected to one resource and four neighboring switches, and each resource is connected to one switch. A resource can be a processor core, memory, an FPGA, a custom hardware block or any other intellectual property (LP) block, which fits into the available slot and complies with the interface of the NOC. The NOC architecture essentially is the onchip communication infrastructure comprising the physical layer, the data link layer and the network layer of the OSI protocol stack. We define the concept of a region, which occupies an area of any number of resources and switches. This concept allows the NOC to accommodate large resources such as large memory banks, FPGA areas, or special purpose computation resources such as high performance multiprocessors. The NOC design methodology consists of two phases. In the first phase a concrete architecture is derived from the general NOC template. The concrete architecture defines the number of switches and shape of the network, the kind and shape of regions and the number and kind of resources. The second phase maps the application onto the concrete architecture to form a concrete product.
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| 43. |
- Kyriakakis, Eleftherios, et al.
(författare)
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Implementation of a Fault-Tolerant, Globally-Asynchronous-Locally-Synchronous, Inter-Chip NoC Communication Bridge on FPGAs
- 2017
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Ingår i: Proceeding of the 2017 IEEE nordic circuits and systems conference (norcas). - : IEEE. ; , s. -6
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Konferensbidrag (refereegranskat)abstract
- Network-on-Chip (NoC) architectures were introduced to help mitigate the bottleneck and scalability issues faced by the traditional bus interconnect in Multi-Processor System-On Chip (MPSoC). Nowadays, many embedded systems host a significant number of micro-controllers and processors (i.e. vehicles, airplanes, satellites, etc.) and as this number continues to increase, traditional bus solutions will start to fail on those platforms as well. NoCs not only offer a scalable solution for MPSoC interconnects but they can also provide a uniform platform of communication to embedded systems with multiple off-chip, often heterogeneous, processors. This leads to the need for investigation on inter-chip communication bridges suitable for transmitting flits/packets across chips and possibly across clock domains. This paper investigates an inter-chip communication link, of an MPSoC NoC architecture which is extended with an off-chip, heterogeneous processor (node) and proposes a scalable, fault-tolerant, globally asynchronous locally synchronous bridge for inter-chip communication. The proposed bridge is implemented on a prototype board of the SEUD KTH experiment where it successfully enables the communication of a NoC distributed over two FPGAs. The inter-chip bridge is verified in-circuit achieving transfer speeds up to 24 MByte/s (approximate to 1.5 Mflit/s) and its ability to correct single bit errors is demonstrated in simulation.
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| 44. |
- Kyriakakis, Eleftherios, et al.
(författare)
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Mitigating Single-Event Upsets in COTS SDRAM using an EDAC SDRAM Controller
- 2017
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Ingår i: Proceedings of the 2017 IEEE NORDIC CIRCUITS AND SYSTEMS CONFERENCE (NORCAS). - : IEEE.
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Konferensbidrag (refereegranskat)abstract
- From deep space missions to low-earth orbit satellites, the natural radiation of space proves to be a hostile environment for electronics. Memory elements in particular are highly susceptible to radiation charge that if latched can cause single-event upsets (SEU, bit-flips) which lead to data corruption and even mission critical failures. On Earth, SDRAM devices are widely used as a cost-effective, high performance storage elements in almost every computer system. However, their physical design makes them highly susceptible to SEUs. Thus, their usage in space application is limited and usually avoided, requiring the use of radiation hardened components which are generally a few generations older and often much more expensive than COTS. In this paper, an off-chip SEU/MBU mitigation mechanism is presented that aims to drastically reduce the probability of data corruption inside a commercial-off-the-shelf (COTS) synchronous dynamic random access memory (SDRAM) using a triple modular redundant (TMR) scheme for data and periodic scrubbing. The proposed mitigation technique is implemented in a novel controller that will be used by the single-event upset detector (SEUD) experiment aboard the KTH MInature STudent (MIST) satellite project.
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| 45. |
- Landernäs, Krister
(författare)
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Implementation of digital-serial LDI/LDD allpass filters
- 2006
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In this thesis, digit-serial implementation of recursive digital filters is considered. The theories presented can be applied to any recursive digital filter, and in this thesis we study the lossless discrete integrator (LDI) allpass filter. A brief introduction regarding suppression of limit cycles at finite wordlength conditions is given, and an extended stability region, where the second-order LDI allpass filter is free from quantization limit cycles, is presented.The realization of digit-serial processing elements, i.e., digit-serial adders and multipliers, is studied. A new digit-serial hybrid adder (DSHA) is presented. The adder can be pipelined to the bit level with a short arithmetic critical path, which makes it well suited when implementing high-throughput recursive digital filters.Two digit-serial multipliers which can be pipelined to the bit level are considered. It is concluded that a digit-serial/parallelmultiplier based on shift-accumulation(DSAAM) is a good candidate when implementing recursive digital systems, mainly due to low latency. Furthermore, our study shows that low latency will lead to higher throughput and lower power consumption.Scheduling of recursive digit-serial algorithms is studied. It is concluded that implementation issues such as latency and arithmetic critical path are usually required before scheduling considerations can be made. Cyclic scheduling using digit-serial arithmetics is also considered. It is shown that digit-serial cyclic scheduling is very attractive for high-throughput implementations.
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| 46. |
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| 47. |
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| 48. |
- Lenz, Alina, et al.
(författare)
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SAFEPOWER project : Architecture for Safe and Power-Efficient Mixed-Criticality Systems
- 2016
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Ingår i: 19TH EUROMICRO CONFERENCE ON DIGITAL SYSTEM DESIGN (DSD 2016). - : IEEE. - 9781509028160 ; , s. 294-300
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Konferensbidrag (refereegranskat)abstract
- With the ever increasing industrial demand for bigger, faster and more efficient systems, a growing number of cores is integrated on a single chip. Additionally, their performance is further maximized by simultaneously executing as many processes as possible not regarding their criticality. Even safety critical domains like railway and avionics apply these paradigms under strict certification regulations. As the number of cores is continuously expanding, the importance of cost-effectiveness grows. One way to increase the cost-efficiency of such System on Chip (SoC) is to enhance the way the SoC handles its power resources. By increasing the power efficiency, the reliability of the SoC is raised, because the lifetime of the battery lengthens. Secondly, by having less energy consumed, the emitted heat is reduced in the SoC which translates into fewer cooling devices. Though energy efficiency has been thoroughly researched, there is no application of those power saving methods in safety critical domains yet. The EU project SAFEPOWER(1) targets this research gap and aims to introduce certifiable methods to improve the power efficiency of mixed-criticality real-time systems (MCRTES). This paper will introduce the requirements that a power efficient SoC has to meet and the challenges such a SoC has to overcome.
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| 49. |
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| 50. |
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