22,651 research outputs found
Abstract Interpretation with Unfoldings
We present and evaluate a technique for computing path-sensitive interference
conditions during abstract interpretation of concurrent programs. In lieu of
fixed point computation, we use prime event structures to compactly represent
causal dependence and interference between sequences of transformers. Our main
contribution is an unfolding algorithm that uses a new notion of independence
to avoid redundant transformer application, thread-local fixed points to reduce
the size of the unfolding, and a novel cutoff criterion based on subsumption to
guarantee termination of the analysis. Our experiments show that the abstract
unfolding produces an order of magnitude fewer false alarms than a mature
abstract interpreter, while being several orders of magnitude faster than
solver-based tools that have the same precision.Comment: Extended version of the paper (with the same title and authors) to
appear at CAV 201
A Simulation Tool for tccp Programs
The Timed Concurrent Constraint Language tccp is a declarative synchronous concurrent language, particularly suitable for modelling reactive systems. In tccp, agents communicate and synchronise through a global constraint store. It supports a notion of discrete time that allows all non-blocked agents to proceed with their execution simultaneously.
In this paper, we present a modular architecture for the simulation of tccp programs. The tool comprises three main components. First, a set of basic abstract instructions able to model the tccp agent behaviour, the memory model needed to manage the active agents and the state of the store during the execution. Second, the agent interpreter that executes the instructions of the current agent iteratively and calculates the new agents to be executed at the next time instant. Finally, the constraint solver components which are the modules that deal with constraints.
In this paper, we describe the implementation of these components and present an example of a real system modelled in tccp.Universidad de MĂĄlaga. Campus de Excelencia Internacional AndalucĂa Tech
A Concurrency-Agnostic Protocol for Multi-Paradigm Concurrent Debugging Tools
Today's complex software systems combine high-level concurrency models. Each
model is used to solve a specific set of problems. Unfortunately, debuggers
support only the low-level notions of threads and shared memory, forcing
developers to reason about these notions instead of the high-level concurrency
models they chose.
This paper proposes a concurrency-agnostic debugger protocol that decouples
the debugger from the concurrency models employed by the target application. As
a result, the underlying language runtime can define custom breakpoints,
stepping operations, and execution events for each concurrency model it
supports, and a debugger can expose them without having to be specifically
adapted.
We evaluated the generality of the protocol by applying it to SOMns, a
Newspeak implementation, which supports a diversity of concurrency models
including communicating sequential processes, communicating event loops,
threads and locks, fork/join parallelism, and software transactional memory. We
implemented 21 breakpoints and 20 stepping operations for these concurrency
models. For none of these, the debugger needed to be changed. Furthermore, we
visualize all concurrent interactions independently of a specific concurrency
model. To show that tooling for a specific concurrency model is possible, we
visualize actor turns and message sends separately.Comment: International Symposium on Dynamic Language
Towards Efficient Abstractions for Concurrent Consensus
Consensus is an often occurring problem in concurrent and distributed
programming. We present a programming language with simple semantics and
build-in support for consensus in the form of communicating transactions. We
motivate the need for such a construct with a characteristic example of
generalized consensus which can be naturally encoded in our language. We then
focus on the challenges in achieving an implementation that can efficiently run
such programs. We setup an architecture to evaluate different implementation
alternatives and use it to experimentally evaluate runtime heuristics. This is
the basis for a research project on realistic programming language support for
consensus.Comment: 15 pages, 5 figures, symposium: TFP 201
Ensuring Equitable Treatment for People of Color Receiving Audiology Care
Abstract 1- Introduction: As health care providers, serving patients equitably may require concurrent caring for the concerns and demands of family members as well. When striving to provide equitable care to patients of all backgrounds, familial participation throughout an appointment can play a substantial role. Case Presentation: An older adult male patient who used English as a second language presented with moderate, sloping to severe, mixed hearing loss, bilaterally. Hearing aid options were counseled and discussed in detail with the patient and his spouse. Discussion: The patientâs wife played an active role throughout the appointment and served as a valuable advocate. This case serves to remind us that, in some cultures, family participation in the healthcare of a relative is more commonly observed and expected. Conclusion: Family- centered healthcare is a key component for the delivery of a culturally welcoming environment, and this should be a priority for all health professionals.
Abstract 2- Introduction: For patients of color with limited-English proficiency (LEP), cultural safety includes undisputed access to interpreting services during healthcare appointments, whether that be provided through a professional interpreter or a relative. As healthcare providers, we are both ethically and legally bound to have interpreting services available for patients to utilize. Case Presentation: An older adult female patient who used English as a second language presented with severe sloping to profound hearing loss in the right ear and a profound hearing loss in the left. Hearing aid options were presented and discussed in detail with the patient and her adult daughter, who acted as the patientâs interpreter. Discussion: While the patientâs daughter was sufficient in completing the appointment despite the extensive language barrier, some might suggest that a professional interpreter would be beneficial. By the same token, others might argue that using a family member as an interpreter would enhance cultural safety. Conclusion: The advantages and disadvantages of using a professional interpreter over a family member can be largely contended, but the central principle remains: an interpreter must be present in an appointment with a LEP patient
Concurrent constraint programming with process mobility
We propose an extension of concurrent constraint programming with primitives for process migration within a hierarchical network, and we study its semantics. To this purpose, we first investigate a "pure " paradigm for process migration, namely a paradigm where the only actions are those dealing with transmissions of processes. Our goal is to give a structural definition of the semantics of migration; namely, we want to describe the behaviour of the system, during the transmission of a process, in terms of the behaviour of the components. We achieve this goal by using a labeled transition system where the effects of sending a process, and requesting a process, are modeled by symmetric rules (similar to handshaking-rules for synchronous communication) between the two partner nodes in the network. Next, we extend our paradigm with the primitives of concurrent constraint programming, and we show how to enrich the semantics to cope with the notions of environment and constraint store. Finally, we show how the operational semantics can be used to define an interpreter for the basic calculus.
Transforming specifications of observable behaviour into programs
A methodology for deriving programs from specifications of observable
behaviour is described. The class of processes to which this methodology
is applicable includes those whose state changes are fully definable by labelled
transition systems, for example communicating processes without
internal state changes. A logic program representation of such labelled
transition systems is proposed, interpreters based on path searching techniques
are defined, and the use of partial evaluation techniques to derive
the executable programs is described
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