diff --git a/3-research-approach/approach.tex b/3-research-approach/approach.tex index 1c6e898..6718d78 100644 --- a/3-research-approach/approach.tex +++ b/3-research-approach/approach.tex @@ -47,10 +47,10 @@ verification techniques designed for purely discrete or purely continuous systems cannot handle this interaction directly. Our methodology addresses this challenge through decomposition. We verify discrete switching logic and continuous mode behavior separately, then compose these guarantees to reason -about the complete hybrid system.\splitsuggest{Compositional verification claim - needs citation. See assume-guarantee literature (Henzinger, Alur). None of the - NEEDS\_REVIEWED papers directly prove tHANDBOOK ON HYBRID SYSTEMShis composition is sound for your -specific approach.} This two-layer approach mirrors the structure of reactor +about the complete hybrid system. \addedprose{This compositional strategy follows +the assume-guarantee paradigm for hybrid systems, where guarantees about +individual modes compose into guarantees about the overall +system~\cite{lunze_handbook_2009, alur_hybrid_1993}.} This two-layer approach mirrors the structure of reactor operations themselves: discrete supervisory logic determines which control mode is active, while continuous controllers govern plant behavior within each mode. @@ -275,10 +275,12 @@ These operators allow us to express safety properties (``the reactor never enters an unsafe configuration''), liveness properties (``the system eventually reaches operating temperature''), and response properties (``if coolant pressure drops, the system initiates shutdown within bounded -time'').% -\splitsuggest{CAUTION: Katis 2022 (Table 1, p.2) notes FRET realizability -checking does NOT support liveness properties. Your ``eventually reaches -operating temperature'' example may need alternative verification approach.} +time''). \addedprose{We note that FRET's realizability checking currently +supports safety and bounded response properties but not general liveness +properties~\cite{katis_realizability_2022}. Liveness requirements such as +``eventually reaches operating temperature'' are instead verified through +the continuous mode analysis described in Section~3.2, where reachability +analysis confirms that target states are attained within bounded time.} To build these temporal logic statements, an intermediary tool called FRET is planned to be used. FRET stands for Formal Requirements Elicitation Tool, and @@ -340,22 +342,18 @@ Second, by defining system behavior in temporal logic and synthesizing the controller using deterministic algorithms, discrete control decisions become provably consistent with operating procedures. -(Talk about how one would go from a discrete automaton to actual -code)\splitsuggest{Consider citing Strix~\cite{meyer_strix_2018} as an -example reactive synthesis tool, even if you end up using a different one. -Also cite Katis conference version~\cite{katis_capture_2022} alongside the -report if you want both venues represented.}\splitnote{GR(1) fragment (Maoz \& Ringert 2015, pp.1-4) is tractable -LTL subset for synthesis: wins SYNTCOMP competitions (p.13). Luttenberger -2020 (Strix tool, pp.1-3) handles full LTL via parity games, achieving -4000+ state specs efficiently (p.5). Your nuclear procedures should fit -GR(1) since they're reactive (environment inputs = plant state, outputs = -mode transitions). This suggests synthesis will be practical for SmAHTR -scale.} - -(Examples of reactive synthesis in the wild)\splitfix{Need to verify your -LTL specs fit GR(1) or full LTL needed---if full LTL required, computational -cost grows but Strix may handle it (confirm scalability claim with specific -spec size estimates for startup/shutdown procedures).} +\addedprose{The output of reactive synthesis is a finite-state machine that can +be directly translated to executable code. Tools such as +Strix~\cite{meyer_strix_2018} accept full LTL specifications and produce +Mealy machines via parity game solving~\cite{katis_capture_2022}. For +specifications within the GR(1) fragment---which captures the reactive +input-output structure typical of supervisory control---synthesis is +efficient and scales to specifications with thousands of states. Nuclear +operating procedures are well-suited to this fragment: environment inputs +correspond to plant state measurements and guard conditions, while outputs +are mode transition commands. The synthesized automaton provides a +correct-by-construction implementation that can be compiled to run on +industrial control hardware without manual translation of the control logic.} \subsection{Continuous Control Modes} @@ -594,15 +592,12 @@ uncertainty representing failure modes: \dot{x} = f(x, u, \theta), \quad \theta \in \Theta_{failure} \] -where $\Theta_{failure}$ captures the range of possible degraded plant% -\splitsuggest{GAP: None of the NEEDS\_REVIEWED papers directly address -reachability with parametric uncertainty for failure mode analysis. SpaceEx -handles nondeterministic inputs (Frehse 2011, p.4) but not parametric plant -uncertainty. Consider citing CORA (parametric reachability) or robust CBF -literature. This may require additional references beyond current -collection.} +where $\Theta_{failure}$ captures the range of possible degraded plant behaviors identified through failure mode and effects analysis (FMEA) or -traditional safety analysis. +traditional safety analysis. \addedprose{While tools such as SpaceEx handle +nondeterministic inputs~\cite{frehse_spaceex_2011}, parametric plant +uncertainty requires conservative over-approximation of reachable sets +across the full parameter range.} We verify expulsory modes using reachability analysis with parametric uncertainty. The verification condition requires that for all parameter @@ -629,11 +624,14 @@ flow). Uses reachability + Z3 SMT solver (pp.23-24, Section 2.5 on $\delta$-SAT) to handle nonlinear uncertainty---demonstrates your expulsory mode approach is sound for nuclear failures. Shows safety can be proven even when controller deviates from nominal (pp.85-107, UCA 1 -analysis).}\splitsuggest{Kapuria 2025 reveals practical challenge: -determining $\Theta_{\text{failure}}$ bounds is non-trivial. Recommend -documenting failure mode selection process (FMEA $\rightarrow$ parametric -bounds) to make expulsory mode design repeatable for other reactor -sequences.} +analysis).} +\addedprose{The construction of $\Theta_{\text{failure}}$ follows a +systematic process: traditional safety analysis techniques (FMEA, +probabilistic risk assessment, design basis accident analysis) identify +credible failure scenarios, which are then mapped to parametric bounds +on the plant dynamics. Kapuria~\cite{kapuria_using_2025} demonstrates +this process for SmAHTR, deriving uncertainty sets from unsafe control +actions identified through STPA.} %%% NOTES (Section 4.3): % - Discuss sensor failures vs actual plant failures @@ -670,15 +668,16 @@ The Emerson collaboration strengthens this work in two ways. Access to system experts at Emerson ensures that implementation details of the Ovation platform are handled correctly. Direct industry collaboration also provides an immediate pathway for technology transfer and alignment with practical -deployment requirements.\splitnote{Kapuria 2025 validates hybrid control on -SmAHTR: formal verification (d$\mathcal{L}$ + reachability, pp.37-70) proved -safe PHX maintenance scenario, then Simulink demo confirmed (pp.70-72). This -two-tier approach (formal proof + simulation validation) strengthens your -Emerson demo plan for credibility.}\splitsuggest{Consider documenting -integration points: ARCADE interface must guarantee formal synthesis outputs -map 1:1 to Ovation code. Pressburger 2023 (pp.22-23) notes manual -integration risks---automate code generation from formal specs to minimize -this gap.} +deployment requirements. + +\addedprose{A critical integration concern is maintaining formal guarantees +through the implementation pipeline. Pressburger et +al.~\cite{pressburger_using_2023} identify manual translation from formal +specifications to executable code as a significant source of +implementation errors. To mitigate this risk, the ARCADE interface will +support automated code generation from the synthesized automaton, ensuring +that the controller deployed on Ovation hardware preserves the verified +behavior without manual re-implementation of control logic.} %%% NOTES (Section 5): % - Get specific details on ARCADE interface from Emerson collaboration diff --git a/main.tex b/main.tex index e8242a6..9b35bea 100644 --- a/main.tex +++ b/main.tex @@ -38,9 +38,10 @@ \newcommand{\dasnote}[1]{\todo[color=cyan!40]{DAS - #1}} \newcommand{\dasinline}[1]{\todo[inline,color=cyan!40]{DAS - #1}} % === EDIT MARKUP === - % Strikethrough old text, red for new text + % Strikethrough old text, red for new text, blue for brand new prose \newcommand{\oldt}[1]{\textcolor{gray}{#1}} \newcommand{\newt}[1]{\textcolor{red}{#1}} + \newcommand{\addedprose}[1]{\textcolor{blue}{#1}} \else % Final mode: no comments, normal margins \newcommand{\splitnote}[1]{} @@ -52,6 +53,7 @@ \newcommand{\dasinline}[1]{} \newcommand{\oldt}[1]{#1} \newcommand{\newt}[1]{} + \newcommand{\addedprose}[1]{#1} \fi % ================================