Session Communication and Integration

The scenario-based specification of a large distributed system is usually naturally decomposed into various modules. The integration of specification modules contrasts to the parallel composition of program components, and includes various ways such as scenario concatenation, choice, and nesting. The recent development of multiparty session types for process calculi provides useful techniques to accommodate the protocol modularisation, by encoding fragments of communication protocols in the usage of private channels for a class of agents. In this paper, we extend forgoing session type theories by enhancing the session integration mechanism. More specifically, we propose a novel synchronous multiparty session type theory, in which sessions are separated into the communicating and integrating levels. Communicating sessions record the message-based communications between multiple agents, whilst integrating sessions describe the integration of communicating ones. A two-level session type system is developed for pi-calculus with syntactic primitives for session establishment, and several key properties of the type system are studied. Applying the theory to system description, we show that a channel safety property and a session conformance property can be analysed. Also, to improve the utility of the theory, a process slicing method is used to help identify the violated sessions in the type checking.Comment: A short version of this paper is submitted for revie

Centrin 2 is required for mouse olfactory ciliary trafficking and development of ependymal cilia planar polarity

pre-printCentrins are ancient calmodulin-related Ca2-binding proteins associated with basal bodies. In lower eukaryotes, Centrin2 (CETN2) is required for basal body replication and positioning, although its function in mammals is undefined. We generated a germline CETN2 knock-out (KO) mouse presenting with syndromic ciliopathy including dysosmia and hydrocephalus. Absence of CETN2 leads to olfactory cilia loss, impaired ciliary trafficking of olfactory signaling proteins, adenylate cyclase III (ACIII), and cyclic nucleotide-gated (CNG) channel, as well as disrupted basal body apical migration in postnatal olfactory sensory neurons (OSNs). In mutant OSNs, cilia baseanchoring of intraflagellar transport components IFT88, the kinesin-II subunit KIF3A, and cytoplasmic dynein 2 appeared compromised. Although the densities of mutant ependymal and respiratory cilia were largely normal, the planar polarity of mutant ependymal cilia was disrupted, resulting in uncoordinated flow of CSF. Transgenic expression of GFP-CETN2 rescued the Cetn2-deficiency phenotype. These results indicate that mammalian basal body replication and ciliogenesis occur independently of CETN2; however, mouse CETN2 regulates protein trafficking of olfactory cilia and participates in specifying planar polarity of ependymal cilia

COVID-19 vaccination coverage and its cognitive determinants among older adults in Shanghai, China, during the COVID-19 epidemic

ObjectivesThis study aimed to examine the coverage of coronavirus disease 2019 (COVID-19) vaccination and its cognitive determinants among older adults.MethodsA cross-sectional study was conducted using a questionnaire to conduct a survey among 725 Chinese older adults aged 60 years and above in June 2022, 2 months after the mass COVID-19 outbreak in Shanghai, China. The questionnaire covered demographic characteristics, COVID-19 vaccination status, internal risk perception, knowledge, and attitude toward the efficacy and safety of COVID-19 vaccines.ResultsThe vaccination rate was 78.3% among the surveyed individuals. Self-reported reasons for unwillingness to get vaccinated (multiple selections) were “concerns about acute exacerbation of chronic diseases after vaccination (57.3%)” and “concerns regarding vaccine side effects (41.4%).” Compared to the unvaccinated group, the vaccinated group tended to have a higher score in internal risk perception (t = 2.64, P < 0.05), better knowledge of COVID-19 vaccines (t = 5.84, P < 0.05), and a more positive attitude toward the efficacy and safety of COVID-19 vaccines (t = 7.92, P < 0.05). The path analysis showed that the cognitive effect on vaccination behavior is relatively large, followed by the internal risk perception, and then the attitude toward COVID-19 vaccines. The more knowledgeable the participants were about COVID-19 vaccines, the more likely they were to receive the COVID-19 vaccines. In the multivariate logistic regression, the increased coverage of COVID-19 vaccination was associated with reduced age (OR = 0.53 95% CI 0.43–0.66, P < 0.001), being a resident in other places than Shanghai (OR = 0.40, 95% CI 0.17–0.92, P < 0.05), a shorter time of lockdown (OR = 0.33, 95% CI 0.13–0.83, P < 0.05), a history of other vaccines (OR = 2.58, 95% CI 1.45–4.60, P < 0.01), a fewer number of chronic diseases (OR = 0.49, 95% CI 0.38–0.62, P < 0.001), better knowledge about COVID-19 vaccines (OR = 1.60, 95% CI 1.17–2.19, P < 0.01), and a positive attitude toward COVID-19 vaccines (OR = 9.22, 95% CI 4.69–18.09, P < 0.001).ConclusionAcquiring accurate knowledge and developing a positive attitude toward COVID-19 vaccines are important factors associated with COVID-19 vaccination. Disseminating informed information on COVID-19 vaccines and ensuring efficacious communication regarding their efficacy and safety would enhance awareness about COVID-19 vaccination among older adults and consequently boost their vaccination coverage

On the expected discounted penalty function for the continuous-time compound binomial risk model

In this paper, we consider the expected discounted penalty function (i.e., the Gerber-Shiu function) for the continuous-time compound binomial risk model. A recursive equation and the Laplace transform of this function are obtained. Some properties related to the moment of the surplus immediately before ruin, the moment of the deficit at ruin and the Laplace transform of the ruin time are obtained by appropriate choices of parameters of the penalty function. Finally, an example is given for the case when the claim-size distribution is geometric.60J25 60G20

Semantic Analysis of Component-aspect Dynamism for Connector-based Architecture Styles

Architecture Description Languages usually specify software architectures in the levels of types and instances. Components instantiate component types by parameterization and type conformance. Behavioral analysis of dynamic architectures needs to deal with the uncertainty of actual configurations of components, even if the type-level architectural descriptions are explicitly provided. This paper addresses this verification difficulty for connector-based architecture styles, in which all communication channels of a system are between components and a connector. The contribution of this paper is two-fold: (1) We propose a process-algebraic model, in which the main architectural concepts (such as component type and component conformance) and several fundamental architectural properties (i.e.~deadlock-freedom, non-starvation, conservation, and completeness) are formulated. (2) We demonstrate that the state space of verification of these properties can be reduced from the entire universe of possible configurations to specific configurations that are fixed according to the type-level architectural descriptions. © 2012 IEEE

Effects of Key Parameters on Airfoil Aerodynamics Using Co-Flow Jet Active Flow Control

The Co-Flow Jet (CFJ) technique is an effective way to enhance the aerodynamics of airfoils. The present study is to comprehensively investigate the effects of CFJ key parameters, viz., the jet momentum coefficient, the injection slot location, the injection slot size, the suction slot location, the suction slot size, and the suction slot angle, on the airfoil aerodynamic characteristics based on the numerical method of Reynolds Averaged Navier-Stokes (RANS) equations coupled with the Spalart-Allmaras (S-A) turbulence model. The numerical method is validated by a CFJ6415 airfoil case, and a relatively good agreement with the experiment is achieved. The results show that a larger jet momentum coefficient is more conducive to lift enhancement, drag reduction, and stall margin enlargement. However, a relatively smaller jet momentum coefficient could increase the corrected aerodynamic efficiency at small angles of attack. The variation of the injection slot location is barely influential to the lift coefficient. With the increase of the injection slot size, the power coefficient first decreases and then increases, and the corrected aerodynamic efficiency first increases and then decreases. The drag coefficient increases monotonously as the suction slot location moves downstream. Furthermore, a relatively smaller suction slot size or a larger suction slot angle could better reduce the drag and enhance the CFJ airfoil aerodynamics

Effects of Key Parameters on Airfoil Aerodynamics Using Co-Flow Jet Active Flow Control

The Co-Flow Jet (CFJ) technique is an effective way to enhance the aerodynamics of airfoils. The present study is to comprehensively investigate the effects of CFJ key parameters, viz., the jet momentum coefficient, the injection slot location, the injection slot size, the suction slot location, the suction slot size, and the suction slot angle, on the airfoil aerodynamic characteristics based on the numerical method of Reynolds Averaged Navier-Stokes (RANS) equations coupled with the Spalart-Allmaras (S-A) turbulence model. The numerical method is validated by a CFJ6415 airfoil case, and a relatively good agreement with the experiment is achieved. The results show that a larger jet momentum coefficient is more conducive to lift enhancement, drag reduction, and stall margin enlargement. However, a relatively smaller jet momentum coefficient could increase the corrected aerodynamic efficiency at small angles of attack. The variation of the injection slot location is barely influential to the lift coefficient. With the increase of the injection slot size, the power coefficient first decreases and then increases, and the corrected aerodynamic efficiency first increases and then decreases. The drag coefficient increases monotonously as the suction slot location moves downstream. Furthermore, a relatively smaller suction slot size or a larger suction slot angle could better reduce the drag and enhance the CFJ airfoil aerodynamics

Corrosion mechanism of micro-arc oxidation treated biocompatible AZ31 magnesium alloy in simulated body fluid

AbstractThe rapid degradation of magnesium (Mg) based alloys has prevented their further use in orthopedic trauma fixation and vascular intervention, and therefore it is essential to investigate the corrosion mechanism for improving the corrosion resistance of these alloys. In this work, the effect of applied voltage on the surface morphology and the corrosion behavior of micro-arc oxidation (MAO) with different voltages were carried out to obtain biocompatible ceramic coatings on AZ31 Mg alloy. The effects of applied voltage on the surface morphology and the corrosion behavior of MAO samples in the simulated body fluid (SBF) were studied systematically. Scanning electron microscope (SEM) and X-ray diffractometer (XRD) were employed to characterize the morphologies and phase compositions of coating before and after corrosion. The results showed that corrosion resistance of the MAO coating obtained at 250V was better than the others in SBF. The dense layer of MAO coating and the corrosion precipitation were the key factors for corrosion behavior. The corrosion of precipitation Mg(OH)2 and the calcium phosphate (Ca–P) minerals on the surface of MAO coatings could enhance their corrosion resistance effectively. In addition, the mechanism of MAO coated Mg alloys was proposed