Thread-local, step-local proof obligations for refinement of state-based concurrent systems

This paper presents a proof technique for proving refinements for general state-based models of concurrent systems that reduces proving forward simulations to thread-local, step-local proof obligations. Instances of this proof technique should be applicable to systems specified with ASM rules, B events, or Z operations. To exemplify the proof technique, we demonstrate it with a simple case study that verifies linearizability of a lock-free implementation of concurrent hash sets by showing that it refines an abstract concurrent system with atomic operations. Our theorem prover KIV translates programs to a set of transition rules and generates proof obligations according to the technique

Shell-Model Study of Shears Bands in Light Pb Nuclei

Spherical shell-model calculations have been performed in the configuration space ( s1/2h9/2i13/2) and (p1/2p3/2f5/2i13/2) for protons and neutrons, respectively, in order to interpret the sequences of strong dipole transitions found in neutron-deficient Pb isotopes. Regular dipole bands are found if several high-j protons and high-j neutron holes are interacting with neutrons in the low-spin (fp) orbitals. The calculated B(M1) values are in the order of several µN2 for the deltaJ=1 transitions, and the crossover E2 transitions are very weak. The mechanism generating the dipole bands is found to be the same as in the tilted axis cranking mean-field description

Flashix: modular verification of a concurrent and crash-safe flash file system

The Flashix project has developed the first realistic verified file system for Flash memory. This paper gives an overview over the project and the theory used. Specification is based on modular components and subcomponents, which may have concurrent implementations connected via refinement. Functional correctness and crash-safety of each component is verified separately. We highlight some components that were recently added to improve efficiency, such as file caches and concurrent garbage collection. The project generates 18K of C code that runs under Linux. We evaluate how efficiency has improved and compare to UBIFS, the most recent flash file system implementation available for the Linux kernel

Towards Low-Jitter and Energy-Efficient Data Processing in Cyber-Physical Information Systems

Cyber-physical systems build the backbone of today\u27s information systems and implement, for example, complex control applications that strictly rely on sensor data. Thus, it is inherently important for cyber-physical systems to provide a reliable data path throughout the entire system: from the sensor nodes to the data post-processing infrastructure in networked environments (e.g., edge and cloud infrastructure). This paper analyzes system-level aspects of the data path of cyber-physical systems (i.e., storage components and file systems) and reveals limitations of current technologies. To improve the current state of the art, we present the implementation of an embedded file system with low jitter which improves predictability characteristics of cyber-physical systems