2,157 research outputs found
Sustainable Fault-handling Of Reconfigurable Logic Using Throughput-driven Assessment
A sustainable Evolvable Hardware (EH) system is developed for SRAM-based reconfigurable Field Programmable Gate Arrays (FPGAs) using outlier detection and group testing-based assessment principles. The fault diagnosis methods presented herein leverage throughput-driven, relative fitness assessment to maintain resource viability autonomously. Group testing-based techniques are developed for adaptive input-driven fault isolation in FPGAs, without the need for exhaustive testing or coding-based evaluation. The techniques maintain the device operational, and when possible generate validated outputs throughout the repair process. Adaptive fault isolation methods based on discrepancy-enabled pair-wise comparisons are developed. By observing the discrepancy characteristics of multiple Concurrent Error Detection (CED) configurations, a method for robust detection of faults is developed based on pairwise parallel evaluation using Discrepancy Mirror logic. The results from the analytical FPGA model are demonstrated via a self-healing, self-organizing evolvable hardware system. Reconfigurability of the SRAM-based FPGA is leveraged to identify logic resource faults which are successively excluded by group testing using alternate device configurations. This simplifies the system architect\u27s role to definition of functionality using a high-level Hardware Description Language (HDL) and system-level performance versus availability operating point. System availability, throughput, and mean time to isolate faults are monitored and maintained using an Observer-Controller model. Results are demonstrated using a Data Encryption Standard (DES) core that occupies approximately 305 FPGA slices on a Xilinx Virtex-II Pro FPGA. With a single simulated stuck-at-fault, the system identifies a completely validated replacement configuration within three to five positive tests. The approach demonstrates a readily-implemented yet robust organic hardware application framework featuring a high degree of autonomous self-control
inSense: A Variation and Fault Tolerant Architecture for Nanoscale Devices
Transistor technology scaling has been the driving force in improving the size, speed, and power consumption of digital systems. As devices approach atomic size, however, their reliability and performance are increasingly compromised due to reduced noise margins, difficulties in fabrication, and emergent nano-scale phenomena. Scaled CMOS devices, in particular, suffer from process variations such as random dopant fluctuation (RDF) and line edge roughness (LER), transistor degradation mechanisms such as negative-bias temperature instability (NBTI) and hot-carrier injection (HCI), and increased sensitivity to single event upsets (SEUs). Consequently, future devices may exhibit reduced performance, diminished lifetimes, and poor reliability.
This research proposes a variation and fault tolerant architecture, the inSense architecture, as a circuit-level solution to the problems induced by the aforementioned phenomena. The inSense architecture entails augmenting circuits with introspective and sensory capabilities which are able to dynamically detect and compensate for process variations, transistor degradation, and soft errors. This approach creates ``smart\u27\u27 circuits able to function despite the use of unreliable devices and is applicable to current CMOS technology as well as next-generation devices using new materials and structures. Furthermore, this work presents an automated prototype implementation of the inSense architecture targeted to CMOS devices and is evaluated via implementation in ISCAS \u2785 benchmark circuits. The automated prototype implementation is functionally verified and characterized: it is found that error detection capability (with error windows from 30-400ps) can be added for less than 2\% area overhead for circuits of non-trivial complexity. Single event transient (SET) detection capability (configurable with target set-points) is found to be functional, although it generally tracks the standard DMR implementation with respect to overheads
Optimizing Scrubbing by Netlist Analysis for FPGA Configuration Bit Classification and Floorplanning
Existing scrubbing techniques for SEU mitigation on FPGAs do not guarantee an
error-free operation after SEU recovering if the affected configuration bits do
belong to feedback loops of the implemented circuits. In this paper, we a)
provide a netlist-based circuit analysis technique to distinguish so-called
critical configuration bits from essential bits in order to identify
configuration bits which will need also state-restoring actions after a
recovered SEU and which not. Furthermore, b) an alternative classification
approach using fault injection is developed in order to compare both
classification techniques. Moreover, c) we will propose a floorplanning
approach for reducing the effective number of scrubbed frames and d),
experimental results will give evidence that our optimization methodology not
only allows to detect errors earlier but also to minimize the
Mean-Time-To-Repair (MTTR) of a circuit considerably. In particular, we show
that by using our approach, the MTTR for datapath-intensive circuits can be
reduced by up to 48.5% in comparison to standard approaches
SOTIF-Compliant Scenario Generation Using Semi-Concrete Scenarios and Parameter Sampling
The SOTIF standard (ISO 21448) requires scenario-based testing to verify and
validate Advanced Driver Assistance Systems and Automated Driving Systems but
does not suggest any practical way to do so effectively and efficiently.
Existing scenario generation approaches either focus on exploring or exploiting
the scenario space. This generally leads to test suites that cover many known
cases but potentially miss edge cases or focused test suites that are effective
but also contain less diverse scenarios. To generate SOTIF-compliant test
suites that achieve higher coverage and find more faults, this paper proposes
semi-concrete scenarios and combines them with parameter sampling to adequately
balance scenario space exploration and exploitation. Semi-concrete scenarios
enable combinatorial scenario generation techniques that systematically explore
the scenario space, while parameter sampling allows for the exploitation of
continuous parameters. Our experimental results show that the proposed concept
can generate more effective test suites than state-of-the-art coverage-based
sampling. Moreover, our results show that including a feedback mechanism to
drive parameter sampling further increases test suites' effectiveness.Comment: accepted at IEEE ITSC 202
Mapping the Structure and Evolution of Software Testing Research Over the Past Three Decades
Background: The field of software testing is growing and rapidly-evolving.
Aims: Based on keywords assigned to publications, we seek to identify
predominant research topics and understand how they are connected and have
evolved.
Method: We apply co-word analysis to map the topology of testing research as
a network where author-assigned keywords are connected by edges indicating
co-occurrence in publications. Keywords are clustered based on edge density and
frequency of connection. We examine the most popular keywords, summarize
clusters into high-level research topics, examine how topics connect, and
examine how the field is changing.
Results: Testing research can be divided into 16 high-level topics and 18
subtopics. Creation guidance, automated test generation, evolution and
maintenance, and test oracles have particularly strong connections to other
topics, highlighting their multidisciplinary nature. Emerging keywords relate
to web and mobile apps, machine learning, energy consumption, automated program
repair and test generation, while emerging connections have formed between web
apps, test oracles, and machine learning with many topics. Random and
requirements-based testing show potential decline.
Conclusions: Our observations, advice, and map data offer a deeper
understanding of the field and inspiration regarding challenges and connections
to explore.Comment: To appear, Journal of Systems and Softwar
Concepts in Testing of Autonomous Systems: Academic Literature and Industry Practice
Testing of autonomous systems is extremely important as many of them are both
safety-critical and security-critical. The architecture and mechanism of such
systems are fundamentally different from traditional control software, which
appears to operate in more structured environments and are explicitly
instructed according to the system design and implementation. To gain a better
understanding of autonomous systems practice and facilitate research on testing
of such systems, we conducted an exploratory study by synthesizing academic
literature with a focus group discussion and interviews with industry
practitioners. Based on thematic analysis of the data, we provide a
conceptualization of autonomous systems, classifications of challenges and
current practices as well as of available techniques and approaches for testing
of autonomous systems. Our findings also indicate that more research efforts
are required for testing of autonomous systems to improve both the quality and
safety aspects of such systems.Comment: 8 pages, 5 figures, conferenc
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