skip to main content


Search for: All records

Creators/Authors contains: "Baker, Nathan"

Note: When clicking on a Digital Object Identifier (DOI) number, you will be taken to an external site maintained by the publisher. Some full text articles may not yet be available without a charge during the embargo (administrative interval).
What is a DOI Number?

Some links on this page may take you to non-federal websites. Their policies may differ from this site.

  1. FPGAs have been shown to operate reliably within harsh radiation environments by employing single-event upset (SEU) mitigation techniques, such as configuration scrubbing, triple-modular redundancy, error correction coding, and radiation aware implementation techniques. The effectiveness of these techniques, however, is limited when using complex system-level designs that employ complex I/O interfaces with single-point failures. In previous work, a complex SoC system running Linux applied several of these techniques only to obtain an improvement of 14\(\times\)in mean time to failure (MTTF). A detailed post-radiation fault analysis found that the limitations in reliability were due to the DDR interface, the global clock network, and interconnect. This article applied a number of design-specific SEU mitigation techniques to address the limitations in reliability of this design. These changes include triplicating the global clock, optimizing the placement of the reduction output voters and input flip-flops, and employing a mapping technique called “striping.” The application of these techniques improved MTTF of the mitigated design by a factor of 1.54\(\times\)and thus provides a 22.8X\(\times\)MTTF improvement over the unmitigated design. A post-radiation fault analysis using BFAT was also performed to find the remaining design vulnerabilities.

     
    more » « less
    Free, publicly-accessible full text available September 30, 2025
  2. Amavilah, Voxi Heinrich (Ed.)
    Background

    The fast-changing labor market highlights the need for an in-depth understanding of occupational mobility impacted by technological change. However, we lack a multidimensional classification scheme that considers similarities of occupations comprehensively, which prevents us from predicting employment trends and mobility across occupations. This study fills the gap by examining employment trends based on similarities between occupations.

    Method

    We first demonstrated a new method that clusters 756 occupation titles based on knowledge, skills, abilities, education, experience, training, activities, values, and interests. We used the Principal Component Analysis to categorize occupations in the Standard Occupational Classification, which is grouped into a four-level hierarchy. Then, we paired the occupation clusters with the occupational employment projections provided by the U.S. Bureau of Labor Statistics. We analyzed how employment would change and what factors affect the employment changes within occupation groups. Particularly, we specified factors related to technological changes.

    Results

    The results reveal that technological change accounts for significant job losses in some clusters. This poses occupational mobility challenges for workers in these jobs at present. Job losses for nearly 60% of current employment will occur in low-skill, low-wage occupational groups. Meanwhile, many mid-skilled and highly skilled jobs are projected to grow in the next ten years.

    Conclusion

    Our results demonstrate the utility of our occupational classification scheme. Furthermore, it suggests a critical need for skills upgrading and workforce development for workers in declining jobs. Special attention should be paid to vulnerable workers, such as older individuals and minorities.

     
    more » « less
  3. FPGAs are increasingly being used in space and other harsh radiation environments. However, SRAM-based FPGAs are susceptible to radiation in these environments and experience upsets within the configuration memory (CRAM), causing design failure. The effects of CRAM upsets can be mitigated using triple-modular redundancy and configuration scrubbing. This work investigates the reliability of a soft RISC-V SoC system executing the Linux operating system mitigated by TMR and configuration scrubbing. In particular, this paper analyzes the failures of this triplicated system observed at a high-energy neutron radiation experiment. Using a bitstream fault analysis tool, the failures of this system caused by CRAM upsets are traced back to the affected FPGA resource and design logic. This fault analysis identifies the interconnect and I/O as the most vulnerable FPGA resources and the DDR controller logic as the design logic most likely to cause a failure. By identifying the FPGA resources and design logic causing failures in this TMR system, additional design enhancements are proposed to create a more reliable design for harsh radiation environments. 
    more » « less
  4. null (Ed.)