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139 lines
4.6 KiB
Markdown
139 lines
4.6 KiB
Markdown
# Outline of State of the Art
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## Writing is thinking, and this is like journaling
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This research is really about using techniques that we
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already have to make hybrid systems that from the jump are
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provably adherent to requirements and in general that we can
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say what they're gonna do fo sho. Does that make any sense?
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The critical technologies to do this are as follows, in no
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particular order: discrete system theory and reactive
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synthesis, temporal logics, reachability for hybrid systems.
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Things that are adjacent to what I'm doing but aren't what
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I'm doing include stuff by Platzer and all the differential
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dynamic logic stuff. His stuff looks like another way of
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conquering this problem but adds a whole lot of complexity
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and makes synthesis ambiguous. Great at checking, but what
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does that mean for designing?
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I feel like I should get more sources on designing hybrid
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systems. I think there are some books out there about this
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maybe.
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----
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**Outline**
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----
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## 1. Hybrid Control Systems Foundations
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- **Classical hybrid systems theory** (Branicky, Liberzon,
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Morse - switching systems)
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- **Hybrid automata and modeling** (Henzinger, Alur, Dill)
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- **Stability analysis for switching systems** (Shorten,
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Narendra, Lin & Antsaklis)
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**Key points to include:**
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- Definition of hybrid systems and why they're needed for
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complex control
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- Challenges in stability analysis when switching between
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controllers
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- Gap between individual mode stability and overall system
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stability
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- Motivate why traditional control theory alone is
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insufficient
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## 2. Discrete Controller Synthesis
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- **Reactive synthesis from temporal logic** (Pnueli, Bloem,
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Ehlers)
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- **Tools like Strix, TuLiP, SLUGS** - emphasize their
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discrete-only assumptions
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- **LTL/GR(1) synthesis** and why these assume instantaneous
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transitions
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**Key points to include:**
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- Power of temporal logic for specifying complex behaviors
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- Success of reactive synthesis in discrete domains
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- Correctness-by-construction guarantees from synthesis
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tools
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- Critical limitation: assumption of instantaneous state
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changes
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- Why this breaks down for physical systems with continuous
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dynamics
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## 3. Continuous System Verification
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- **Reachability analysis** (Girard, Le Guernic, Althoff -
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especially for nonlinear systems)
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- **Linear system verification** (Boyd, Dullerud - classical
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control meets verification)
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- **Set-based methods** (Mitchell, Tomlin for
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Hamilton-Jacobi reachability)
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**Key points to include:**
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- Mature tools for analyzing continuous dynamics
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- Reachability as the fundamental verification problem
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- Computational challenges for nonlinear systems
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- Gap: these are analysis tools, not synthesis tools
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- They tell you if a controller works, but don't help design
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it
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## 4. Existing Hybrid Verification Approaches
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- **Platzer's differential dynamic logic** (as you noted -
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good for verification, unclear for synthesis)
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- **SpaceEx, Flow*, dReach** - model checking tools that
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don't synthesize
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- **Contract-based design** (Benveniste,
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Sangiovanni-Vincentelli)
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**Key points to include:**
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- Current approaches focus on verification after design
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- Platzer's dL: powerful for proving correctness, but
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synthesis unclear
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- Model checking tools require pre-designed controllers
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- Contract-based approaches: compositional but still
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verification-focused
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- Missing: unified synthesis framework that handles both
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discrete and continuous
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## 5. The Gap You're Filling
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- **Why discrete synthesis + continuous verification hasn't
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been unified**
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- **Challenges with non-instantaneous transitions**
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- **The synthesis vs. verification divide**
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**Key points to include:**
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- Fundamental mismatch: discrete synthesis assumes instant
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transitions
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- Physical reality: transitions take time and follow
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continuous trajectories
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- Current workflow: synthesize discrete, design continuous,
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then verify
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- Your contribution: unified framework for
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correct-by-construction hybrid synthesis
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- Nuclear startup as ideal testbed: well-defined continuous
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dynamics + explicit procedural requirements
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## Key Sources to Hunt Down
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**Foundational hybrid systems:**
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- Branicky's "Multiple Lyapunov functions and other analysis
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tools"
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- Liberzon's "Switching in Systems and Control"
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- Antsaklis & Koutsoukos survey papers
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**Reactive synthesis:**
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- Ehlers & Topcu on GR(1) synthesis
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- Recent Strix papers (Meyer, Sickert, Luttenberger)
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- Wongpiromsarn's work on TuLiP
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**Hybrid verification:**
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- Althoff's reachability analysis work
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- Girard's papers on abstraction-based verification
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- Any recent survey on hybrid system verification tools
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**Nuclear/critical systems control:**
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- Look for papers on autonomous nuclear plant operation
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- Regulatory papers on control system requirements (might be
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more engineering sources)
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