White paper: A plan for cooperation between NASA and DARPA to establish a center for advanced architectures

Large, complex computer systems require many years of development. It is recognized that large scale systems are unlikely to be delivered in useful condition unless users are intimately involved throughout the design process. A mechanism is described that will involve users in the design of advanced computing systems and will accelerate the insertion of new systems into scientific research. This mechanism is embodied in a facility called the Center for Advanced Architectures (CAA). CAA would be a division of RIACS (Research Institute for Advanced Computer Science) and would receive its technical direction from a Scientific Advisory Board established by RIACS. The CAA described here is a possible implementation of a center envisaged in a proposed cooperation between NASA and DARPA

Refactoring preserves security

Refactoring allows changing a program without changing its behaviour from an observer’s point of view. To what extent does this invariant of behaviour also preserve security? We show that a program remains secure under refactoring. As a foundation, we use the Decentralized Label Model (DLM) for specifying secure information flows of programs and transition system models for their observable behaviour. On this basis, we provide a bisimulation based formal definition of refactoring and show its correspondence to the formal notion of information flow security (noninterference). This permits us to show security of refactoring patterns that have already been practically explored

Cellular automaton rules conserving the number of active sites

This paper shows how to determine all the unidimensional two-state cellular automaton rules of a given number of inputs which conserve the number of active sites. These rules have to satisfy a necessary and sufficient condition. If the active sites are viewed as cells occupied by identical particles, these cellular automaton rules represent evolution operators of systems of identical interacting particles whose total number is conserved. Some of these rules, which allow motion in both directions, mimic ensembles of one-dimensional pseudo-random walkers. Numerical evidence indicates that the corresponding stochastic processes might be non-Gaussian.Comment: 14 pages, 5 figure

Using theorem provers to increase the precision of dependence analysis for information flow control

Information flow control (IFC) is a category of techniques for enforcing information flow properties. In this paper we present the Combined Approach, a novel IFC technique that combines a scalable system-dependence-graph-based (SDG-based) approach with a precise logic-based approach based on a theorem prover. The Combined Approach has an increased precision compared with the SDG-based approach on its own, without sacrificing its scalability. For every potential illegal information flow reported by the SDG-based approach, the Combined Approach automatically generates proof obligations that, if valid, prove that there is no program path for which the reported information flow can happen. These proof obligations are then relayed to the logic-based approach. We also show how the SDG-based approach can provide additional information to the theorem prover that helps decrease the verification effort. Moreover, we present a prototypical implementation of the Combined Approach that uses the tools JOANA and KeY as the SDG-based and logic-based approach respectively

Integration of Static and Dynamic Analysis Techniques for Checking Noninterference

In this article, we present an overview of recent combinations of deductive program verification and automatic test generation on the one hand and static analysis on the other hand, with the goal of checking noninterference. Noninterference is the non-functional property that certain confidential information cannot leak to certain public output, i.e., the confidentiality of that information is always preserved. We define the noninterference properties that are checked along with the individual approaches that we use in different combinations. In one use case, our framework for checking noninterference employs deductive verification to automatically generate tests for noninterference violations with an improved test coverage. In another use case, the framework provides two combinations of deductive verification with static analysis based on system dependence graphs to prove noninterference, thereby reducing the effort for deductive verification

Quantum interface of an electron and a nuclear ensemble.

Coherent excitation of an ensemble of quantum objects underpins quantum many-body phenomena and offers the opportunity to realize a memory that stores quantum information. Thus far, a deterministic and coherent interface between a spin qubit and such an ensemble has remained elusive. In this study, we first used an electron to cool the mesoscopic nuclear spin ensemble of a semiconductor quantum dot to the nuclear sideband-resolved regime. We then implemented an all-optical approach to access individual quantized electronic-nuclear spin transitions. Lastly, we performed coherent optical rotations of a single collective nuclear spin excitation-a spin wave. These results constitute the building blocks of a dedicated local memory per quantum-dot spin qubit and promise a solid-state platform for quantum-state engineering of isolated many-body systems

Mitochondrial DNA: Hotspot for potential gene modifiers regulating hypertrophic cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is a prevalent and untreatable cardiovascular disease with a highly complex clinical and genetic causation. HCM patients bearing similar sarcomeric mutations display variable clinical outcomes, implying the involvement of gene modifiers that regulate disease progression. As individuals exhibiting mutations in mitochondrial DNA (mtDNA) present cardiac phenotypes, the mitochondrial genome is a promising candidate to harbor gene modifiers of HCM. Herein, we sequenced the mtDNA of isogenic pluripotent stem cell-cardiomyocyte models of HCM focusing on two sarcomeric mutations. This approach was extended to unrelated patient families totaling 52 cell lines. By correlating cellular and clinical phenotypes with mtDNA sequencing, potentially HCM-protective or -aggravator mtDNA variants were identified. These novel mutations were mostly located in the non-coding control region of the mtDNA and did not overlap with those of other mitochondrial diseases. Analysis of unrelated patients highlighted family-specific mtDNA variants, while others were common in particular population haplogroups. Further validation of mtDNA variants as gene modifiers is warranted but limited by the technically challenging methods of editing the mitochondrial genome. Future molecular characterization of these mtDNA variants in the context of HCM may identify novel treatments and facilitate genetic screening in cardiomyopathy patients towards more efficient treatment options

Diagnosis and Threat Detection Capabilities of the SERENITY Monitoring Framework

The SERENITY monitoring framework offers mechanisms for diagnosing the causes of violations of security and dependability (S&D) properties and detecting potential violations of such properties, called “threats”. Diagnostic information and threat detection are often necessary for deciding what an appropriate reaction to a violation is and taking pre-emptive actions against predicted violations, respectively. In this chapter, we describe the mechanisms of the SERENITY monitoring framework which generate diagnostic information for violations of S&D properties and detecting threats