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Commercial off-the-shelf (COTS) microcontrollers can be useful for non-critical processing on spaceborne platforms. Many of these microprocessors are inexpensive and consume little power. However, the software running on these processors is vulnerable to radiation upsets, which can cause unpredictable program execution or corrupt data. Space missions cannot allow these errors to interrupt functionality or destroy gathered data. As a result, several techniques have been developed to reduce the effect of these upsets. Some proposed techniques involve altering the processor hardware, which is impossible for a COTS device. Alternately, the software running on the microcontroller can be modified to detect or correct data corruption. There have been several proposed approaches for software mitigation. Some take advantage of advanced architectural features, others modify software by hand, and still others focus their techniques on specific microarchitectures. However, these approaches do not consider the limited resources of microcontrollers and are difficult to use across multiple platforms. This thesis explores fully automated software-based mitigation to improve the reliability of microcontrollers and microcontroller software in a high radiation environment. Several difficulties associated with automating software protection in the compilation step are also discussed. Previous mitigation techniques are examined, resulting in the creation of COAST (COmpiler-Assisted Software fault Tolerance), a tool that automatically applies software protection techniques to user code. Hardened code has been verified by a fault injection campaign; the mean work to failure increased, on average, by 21.6x. When tested in a neutron beam, the neutron cross sections of programs decreased by an average of 23x, and the average mean work to failure increased by 5.7x.

Modern society is unquestionably heavily reliant on supply of electricity. Hence, the power system is one of the important infrastructures for future growth. However, the power system of today was designed for a stable radial flow of electricity from large power plants to the customers and not for the type of changes it is presently being exposed to, like large scale integration of electric vehicles, wind power plants, residential photovoltaic systems etc. One aspect of power system control particular exposed to these changes is the design of power system control and protection functionality. Problems occur when the flow of electricity changes from a unidirectional radial flow to a bidirectional. Such an implication requires redesign of control and protection functionality as well as introduction of new information and communication technology (ICT). To make matters worse, the closer the interaction between the power system and the ICT systems the more complex the matter becomes from a reliability perspective. This problem is inherently cyber-physical, including everything from system software to power cables and transformers, rather than the traditional reliability concern of only focusing on power system components. The contribution of this thesis is a framework for reliability analysis, utilizing system modeling concepts that supports the industrial engineering issues that follow with the imple-mentation of modern substation automation systems. The framework is based on a Bayesian probabilistic analysis engine represented by Probabilistic Relational Models (PRMs) in com-bination with an Enterprise Architecture (EA) modeling formalism. The gradual development of the framework is demonstrated through a number of application scenarios based on substation automation system configurations. This thesis is a composite thesis consisting of seven papers. Paper 1 presents the framework combining EA, PRMs and Fault Tree Analysis (FTA). Paper 2 adds primary substation equipment as part of the framework. Paper 3 presents a mapping between modeling entities from the EA framework ArchiMate and substation automation system configuration objects from the IEC 61850 standard. Paper 4 introduces object definitions and relations in coherence with EA modeling formalism suitable for the purpose of the analysis framework. Paper 5 describes an extension of the analysis framework by adding logical operators to the probabilistic analysis engine. Paper 6 presents enhanced failure rates for software components by studying failure logs and an application of the framework to a utility substation automation system. Finally, Paper 7 describes the ability to utilize domain standards for coherent modeling of functions and their interrelations and an application of the framework utilizing software-tool support. / <p>QC 20140505</p>

In the presence of ionizing particles and other high-energy atomic sources, many electronic and computer systems fail. Single event upsets (SEUs) can be mitigated through hardware and/or software methods. Previous research at BYU has introduced COAST, a compiler-based tool that can automatically add software protection schemes to improve fault coverage of programs. This thesis will expand on the work already done with the COAST project by proving its effectiveness across multiple platforms and benchmarks. The ability to automatically add fault protection to arbitrary user programs will be very valuable for many application designers. The results presented herein show that mean work to failure (MWTF) of an application can increase from 1.2x – 36x when protected by COAST. In addition to the results based on bare metal applications, in this thesis we will show that it is both possible and profitable to protect a real-time operating system with COAST. We present experimental results which show that our protection scheme gives a 2x – 100x improvement in MWTF. We also present a fault injection framework that allows for rapid and reliable testing of multiple protection schemes across different benchmarks. The code setup used in this paper is publicly available. We make it public in the hope that it will be useful for others doing similar research to have a concrete starting point.

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The criticality of the applications modeled by the real-time software places stringent requirements on software quality before deploying into real use. Though automated test tools can be used to run a large number of tests efficiently, the functionality of any test tool is not complege without providing a means for analyzing the test results to determine potential problem sub-domains and sub-domains that need to be covered, and estimating the reliability of the modeled system. This thesis outlines a solution strategy and implementation of that strategy for deriving quantitative metrics from domain testing of real-time control software tested via simulation. The key portion of this thesis addresses the combinatorial problems involved with effective evaluation of test coverage and provides the developer with reliability metrics from testing of the software to gain confidence in the test phase of development. The two approaches for reliability analysis- time domain and input domain approaches are studied and a hybrid approach that combines the strengths of both these approaches is proposed. A Reliability analysis Test Tool (RATT) has been developed to implement the proposed strategies. The results show that the metrics are practically feasible to compute and can be applied to most real-time software.

The key objective of database systems is to reliably manage data, whereby high query throughput and low query latency are core requirements. To satisfy these requirements, database systems constantly adapt to novel hardware features. Although it has been intensively studied and commonly accepted that hardware error rates in terms of bit flips increase dramatically with the decrease of the underlying chip structures, most database system research activities neglected this fact, leaving error (bit flip) detection as well as correction to the underlying hardware. Especially for main memory, silent data corruption (SDC) as a result of transient bit flips leading to faulty data is mainly detected and corrected at the DRAM and memory-controller layer. However, since future hardware becomes less reliable and error detection as well as correction by hardware becomes more expensive, this free ride will come to an end in the near future. To further provide a reliable data management, an emerging research direction is employing specific and tailored protection techniques at the database system level. Following that, we are currently developing and implementing an adopted system design for state-of-the-art in-memory column stores. In our lightning talk, we will summarize our current state and outline future work.

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