Consistency in UML and B multi-view specifications

20We present the notion of {\\it consistency relation} in UML and B multi-view specifications. It is defined as a semantic relation between both views. It provides us with a sound basis to define the notion of development operator. An operator models a development step; it separates the design decisions from their expression in the specification formalisms. Operator correctness is defined as a property which guarantees that the application of an operator on a consistent specification state yields a consistent new state. An operator can be proven once and for all to be correct. A classical case-study, the Generalized Railroad Crossing (GRC), demonstrates how the different notions can be put in practice to provide specifiers with a realistic development model

Researching COVID to enhance recovery (RECOVER) pregnancy study: Rationale, objectives and design

Importance Pregnancy induces unique physiologic changes to the immune response and hormonal changes leading to plausible differences in the risk of developing post-acute sequelae of SARS-CoV-2 (PASC), or Long COVID. Exposure to SARS-CoV-2 during pregnancy may also have long-term ramifications for exposed offspring, and it is critical to evaluate the health outcomes of exposed children. The National Institutes of Health (NIH) Researching COVID to Enhance Recovery (RECOVER) Multi-site Observational Study of PASC aims to evaluate the long-term sequelae of SARS-CoV-2 infection in various populations. RECOVER-Pregnancy was designed specifically to address long-term outcomes in maternal-child dyads. Methods RECOVER-Pregnancy cohort is a combined prospective and retrospective cohort that proposes to enroll 2,300 individuals with a pregnancy during the COVID-19 pandemic and their offspring exposed and unexposed in utero, including single and multiple gestations. Enrollment will occur both in person at 27 sites through the Eunice Kennedy Shriver National Institutes of Health Maternal-Fetal Medicine Units Network and remotely through national recruitment by the study team at the University of California San Francisco (UCSF). Adults with and without SARS-CoV-2 infection during pregnancy are eligible for enrollment in the pregnancy cohort and will follow the protocol for RECOVER-Adult including validated screening tools, laboratory analyses and symptom questionnaires followed by more in-depth phenotyping of PASC on a subset of the overall cohort. Offspring exposed and unexposed in utero to SARS-CoV-2 maternal infection will undergo screening tests for neurodevelopment and other health outcomes at 12, 18, 24, 36 and 48 months of age. Blood specimens will be collected at 24 months of age for SARS-CoV-2 antibody testing, storage and anticipated later analyses proposed by RECOVER and other investigators. Discussion RECOVER-Pregnancy will address whether having SARS-CoV-2 during pregnancy modifies the risk factors, prevalence, and phenotype of PASC. The pregnancy cohort will also establish whether there are increased risks of adverse long-term outcomes among children exposed in utero

How to Synthesize Relational Database Transactions From EB 3 Attribute Definitions?

Abstract. EB 3 is a trace-based formal language created for the specification of information systems (IS). Attributes, linked to entities and associations of an IS, are computed in EB 3 by recursive functions on the valid traces of the system. In this paper, we show how to synthesize relational database transactions that correspond to EB 3 attribute definitions. Thus, each EB 3 action is translated into a transaction. EB 3 attribute definitions are analysed to determine the key values affected by each action. To avoid problems with the sequencing of SQL statements in the transactions, temporary variables and/or tables are introduced for these key values.

apis 1 -Automatic Production of Information Systems

The objective of the apis research project is to develop a case tool that generates executable information systems (IS) from formal specifications (abstract models). In other words, apis aims at automating as much as possible the production of IS by lifting the level of abstraction at which software designers work. Instead of spending most of their time designing, programming and testing at a very low level of abstraction, software designers will be able to concentrate on specifying and validating; the apis case tool will take care of generating an executable system from the specification. The foundations of the case tool are abstract models of IS (formal functional specifications) and algorithms that generates an executable system from these models (modelbased interface development environment -MB-IDE), and specification interpretation. The apis project has to a) define a comprehensive set of integrated models for information systems, b) develop new algorithms for specification interpretation and code generation, and c) implement them in a case tool. The eb 3 specification language will be the foundation for the models The apis project will be the first to study the automation of information systems production from formal specifications. The success of the apis project would represent a significant breakthrough in terms of productivity and quality in IS development. apis could cut up to 50 % of the cost of IS development, because it would relieve software designers from design, programming and testing. Consequently, it would also avoid faults introduced during these activities. Background and Related Work Information Systems IS are generally characterized by large data structures which are modified or queried by several users in concurrency. The difficulty of these systems typically resides in managing complex relationships between data structures, in complex calculations involving several data structures, in processing large volume of data, and in preserving data integrity through concurrent updates by several users. IS typically have little hard real-time constraints or interprocess communication. An IS can be decomposed in three parts: i) the functional behavior (also called business logic), ii) the user interface , and iii) the database. The functional behavior defines the transactions of the system, which are of two types: a) update transactions modify the internal state of the system which is stored in a database, b) inquiry transactions display information about the system state (database). The recent technological developments in IS mostly apply to the programming phase. Database management systems (DBMS), key elements of IS, now offer sophisticated distribution and concurrency control mechanisms, support very large databases, and offer sophisticated querying facilities. Technical breakthroughs like INTERNET, JAVA, CORBA, COM, EJB, frameworks and others make it easier to program distributed information systems or deploy them on the web on various platforms. Some DBMS case tools can generate forms to update-modify-delete records in a table, but this is insufficient to build a real GUI for an information system. 1 Egyptian mythology -a god depicted as a bull, symbolizing fertility and strength in war [OED]. Drawings by Pablo Picasso, 1945

Supplementing a UML development process with B

This paper discusses our experiences of using UML and B together through an illustrative case study. Our approach to using UML and B centers around stereotyping UML classes in order to identify which classes should be modelled in B. We discuss the tensions between the notations, and the compromises that need to be reached in order for B to supplement a UML development. The case study begins from the initial conception of a library system and its use case view in order to demonstrate how the classes were identified

Applying CSP parallel to B to information systems

CSP parallel to B is a formal approach which combines state and event-based descriptions of a system. It enables the automatic verification of dynamic properties using model checking techniques. In this paper we identify a variation on the standard CSP parallel to B architecture so that it is more applicable to support the specification of information systems. We specify a library system using this new architecture. We examine several safety and liveness requirements and demonstrate that we can compositionally verify them using FDR. If a property fails to model check we identify an abstraction technique which enables us to pinpoint the cause of the failure