2,216 research outputs found
On affine usages in signal-based communication
We describe a type system for a synchronous pi-calculus formalising the
notion of affine usage in signal-based communication. In particular, we
identify a limited number of usages that preserve affinity and that can be
composed. As a main application of the resulting system, we show that typable
programs are deterministic
On Observing Dynamic Prioritised Actions in SOC
We study the impact on observational semantics for SOC of priority mechanisms which combine dynamic priority with local pre-emption. We define manageable notions of strong and weak labelled bisimilarities for COWS, a process calculus for SOC, and provide alternative characterisations in terms of open barbed bisimilarities. These semantics show that COWS’s priority mechanisms partially recover the capability to observe receive actions (that could not be observed in a purely asynchronous setting) and that high priority primitives for termination impose specific conditions on the bisimilarities
Relating two standard notions of secrecy
Two styles of definitions are usually considered to express that a security
protocol preserves the confidentiality of a data s. Reachability-based secrecy
means that s should never be disclosed while equivalence-based secrecy states
that two executions of a protocol with distinct instances for s should be
indistinguishable to an attacker. Although the second formulation ensures a
higher level of security and is closer to cryptographic notions of secrecy,
decidability results and automatic tools have mainly focused on the first
definition so far.
This paper initiates a systematic investigation of the situations where
syntactic secrecy entails strong secrecy. We show that in the passive case,
reachability-based secrecy actually implies equivalence-based secrecy for
digital signatures, symmetric and asymmetric encryption provided that the
primitives are probabilistic. For active adversaries, we provide sufficient
(and rather tight) conditions on the protocol for this implication to hold.Comment: 29 pages, published in LMC
Batalin-Vilkovisky Integrals in Finite Dimensions
The Batalin-Vilkovisky method (BV) is the most powerful method to analyze
functional integrals with (infinite-dimensional) gauge symmetries presently
known. It has been invented to fix gauges associated with symmetries that do
not close off-shell. Homological Perturbation Theory is introduced and used to
develop the integration theory behind BV and to describe the BV quantization of
a Lagrangian system with symmetries. Localization (illustrated in terms of
Duistermaat-Heckman localization) as well as anomalous symmetries are discussed
in the framework of BV.Comment: 35 page
Resource Control for Synchronous Cooperative Threads
We develop new methods to statically bound the resources needed for the
execution of systems of concurrent, interactive threads. Our study is concerned
with a \emph{synchronous} model of interaction based on cooperative threads
whose execution proceeds in synchronous rounds called instants. Our
contribution is a system of compositional static analyses to guarantee that
each instant terminates and to bound the size of the values computed by the
system as a function of the size of its parameters at the beginning of the
instant. Our method generalises an approach designed for first-order functional
languages that relies on a combination of standard termination techniques for
term rewriting systems and an analysis of the size of the computed values based
on the notion of quasi-interpretation. We show that these two methods can be
combined to obtain an explicit polynomial bound on the resources needed for the
execution of the system during an instant. As a second contribution, we
introduce a virtual machine and a related bytecode thus producing a precise
description of the resources needed for the execution of a system. In this
context, we present a suitable control flow analysis that allows to formulte
the static analyses for resource control at byte code level
Improving Upper Extremity Motor Skills in Girls with Rett Syndrome Using Virtual Reality
Introduction: Rett Syndrome is a genetic disorder that limits a girl's ability to use her upper extremities for daily activities, such as dressing and playing. One possible intervention to improve upper extremity function in this population is virtual reality, which can be used to increase activity demands during therapy sessions.
Objectives: To determine the feasibility of using internet-based virtual reality intervention for Rett Syndrome (RTT-IVR), to decrease hand wringing/mouthing and increase hand and arm movements away from the midline by identifying attributes and limitations to the proposed intervention.
Materials and Methods: Using FAAST Software and Microsoft Kinect sensor, RTT-IVR was trialed with 6 girls with RTT. Upper extremity movements were used to play free Internet games as means of increasing repetitions and purposeful arm movements. Data regarding attributes and limitations of the RTT-IVR intervention were collected via observation and post-session parent interviews.
Results: Interviews and observation revealed successful game play when games were motivating, clearly established cause and effect, and matched level of cognitive ability of the participant. Limitations include technological glitches regarding Kinect sensor sensitivity and identifying appropriate games for each participant's interests and abilities.
Conclusion: Internet based virtual reality interventions for girls with RTT should be highly individualized to increase motivation and success of intervention
Violence against aged people: a new issue?
O envelhecimento da população mundial é um fato concreto e de conhecimento público. O Brasil inicia seu processo de transição demográfica seguindo o padrão mundial: o aumento do número de idosos com possibilidade de atingir elevadas faixas etárias, o que traz a necessidade de pesquisas nesse campo, devido à demanda apresentada por essa nova parcela da população. A questão da violência doméstica contra idosos tem se ampliado e sugere necessidade de maior campo de investigação nessa área, dado o risco suposto ao qual essa população mais idosa está submetida. O objetivo deste artigo é verificar os estudos relacionados ao tema já realizados no Brasil e em diferentes países, com enfoque epidemiológico. O trabalho apresenta diversos pontos de abordagem da violência contra idosos, considerando questões relacionadas à cultura do envelhecimento, ações de políticas públicas, atuação de equipes de saúde, definição do termo abordado, aspectos legais e éticos da violência contra o idoso. Tal estudo permite ao pesquisador analisar os diferentes aspectos que envolvem a temática, demonstrando a necessidade de pesquisas específicas direcionadas ao tema.The world population is getting older and this is a very well known fact. The demographic transition of the Brazilian population is just beginning, and follows the world pattern: an increase in the number of older persons with an actual chance of reaching higher ages. As a consequence, there is the need of new studies to supply data about this new aspect of the population demands. Household violence against old persons has been growing and this strongly recommends that special research studies should be conducted, in view of the risk to which these individuals are exposed. The objective of this study is to list and analyze Brazilian and international studies related to aged persons, in light of an epidemiological point of view. The article presents many ways of approaching violence against old people, considering the culture of aging, actions of public policies, the practice of health teams, and legal and ethical aspects of violence against aged people. Such a study allows the researcher to analyze different aspects of the theme, showing the need of specific research on the elderly
The Effects of Virtual Reality on the Upper Extremity Skills of Girls with Rett Syndrome: A Single Case Study
Introduction: Rett Syndrome (RTT) is a genetic disorder primarily seen in females that inhibits the use of a girl's hands in everyday activities. A girl with RTT spends the majority of her day engaged in stereotypical hand wringing/mouthing movements at midline of the body. The probable cause behind the neurological effects of RTT is a mutation in the gene that encodes for methyl-CpG protein 2 (MeCP2). The hand wringing/mouthing behaviors preclude a girl with RTT from using the upper extremities in purposeful tasks such as school work, play skills, and other activities of daily living.Objectives: To develop a virtual reality (VR)-based therapeutic intervention that 1) decreases upper extremity stereotypies (repetitive movements that serve no function) that interfere with purposeful arm and hand use and 2) promotes purposeful, goal-directed arm function; improve upper extremity motor skills in girls with RTT.Materials and Methods: Using FAAST Software and Microsoft Kinect sensor, one girl with RTT participated in a 12-week IVR intervention (1 hour/session, 3 sessions/week, 36 total hours). Pre- and post-assessments were administered to examine any changes in upper extremity function.Results: The VR intervention led to improvements in use of the upper extremities to complete self-care activities, an increased number of reaches completed in a 15-minute period, and decreased time engaged in stereotypical hand movements.Conclusion: Future work will add additional support to determine the effectiveness of virtual reality as an intervention for girls with RTT
Flood loss modelling with FLF-IT: a new flood loss function for Italian residential structures
The damage triggered by different flood events costs the Italian economy millions of euros each year. This cost is likely to increase in the future due to climate variability and economic development. In order to avoid or reduce such significant financial losses, risk management requires tools which can provide a reliable estimate of potential flood impacts across the country. Flood loss functions are an internationally accepted method for estimating physical flood damage in urban areas. In this study, we derived a new flood loss function for Italian residential structures (FLF-IT), on the basis of empirical damage data collected from a recent flood event in the region of Emilia-Romagna. The function was developed based on a new Australian approach (FLFA), which represents the confidence limits that exist around the parameterized functional depth–damage relationship. After model calibration, the performance of the model was validated for the prediction of loss ratios and absolute damage values. It was also contrasted with an uncalibrated relative model with frequent usage in Europe. In this regard, a three-fold cross-validation procedure was carried out over the empirical sample to measure the range of uncertainty from the actual damage data. The predictive capability has also been studied for some sub-classes of water depth. The validation procedure shows that the newly derived function performs well (no bias and only 10 % mean absolute error), especially when the water depth is high. Results of these validation tests illustrate the importance of model calibration. The advantages of the FLF-IT model over other Italian models include calibration with empirical data, consideration of the epistemic uncertainty of data, and the ability to change parameters based on building practices across Italy
- …