Using event-B and Modelica to evaluate thermal management strategies in many core systems

Dynamic thermal management is an increasingly critical and complex part of the run-time management of manycore systems. Methods of controlling temperature include thread migration, dynamic voltage and frequency scaling and power gating using various strategies and combinations of each. In the PRiME project we are developing run-time management systems to sustain the scaling of many-core systems. As part of this development we are investigating the relative benefits of different thermal management strategies by co-simulating a Modellica model of the characteristics of a many-core device with a discrete Event-B model of the run-time manager. The results enable us to efficiently design more elaborate experiments on real hardware platforms in order to validate the run time management

MODELFY: A Model-driven Solution for Decision Making based on Fuzzy Information

There exist areas, such as the disease prevention or inclement weather protocols, in which the analysis of the information based on strict protocols require a high level of rigor and security. In this situation, it would be desirable to apply formal methodologies that provide these features. In this scope, recently, it has been proposed a formalism, fuzzy automaton, that captures two relevant aspects for fuzzy information analysis: imprecision and uncertainty. However, the models should be designed by domain experts, who have the required knowledge for the design of the processes, but do not have the necessary technical knowledge. To address this limitation, this paper proposes MODELFY, a novel model-driven solution for designing a decision-making process based on fuzzy automata that allows users to abstract from technical complexities. With this goal in mind, we have developed a framework for fuzzy automaton model design based on a Domain- Specific Modeling Language (DSML) and a graphical editor. To improve the interoperability and functionality of this framework, it also includes a model-to-text transformation that translates the models designed by using the graphical editor into a format that can be used by a tool for data analysis. The practical value of this proposal is also evaluated through a non-trivial medical protocol for detecting potential heart problems. The results confirm that MODELFY is useful for defining such a protocol in a user-friendly and rigorous manner, bringing fuzzy automata closer to domain expert

Extending relational model transformations to better support the verification of increasingly autonomous systems

Over the past decade the capabilities of autonomous systems have been steadily increasing. Unmanned systems are moving from systems that are predominantly remotely operated, to systems that include a basic decision making capability. This is a trend that is expected to continue with autonomous systems making decisions in increasingly complex environments, based on more abstract, higher-level missions and goals. These changes have significant implications for how these systems should be designed and engineered. Indeed, as the goals and tasks these systems are to achieve become more abstract, and the environments they operate in become more complex, are current approaches to verification and validation sufficient? Domain Specific Modelling is a key technology for the verification of autonomous systems. Verifying these systems will ultimately involve understanding a significant number of domains. This includes goals/tasks, environments, systems functions and their associated performance. Relational Model Transformations provide a means to utilise, combine and check models for consistency across these domains. In this thesis an approach that utilises relational model transformation technologies for systems verification, Systems MDD, is presented along with the results of a series of trials conducted with an existing relational model transformation language (QVT-Relations). These trials identified a number of problems with existing model transformation languages, including poorly or loosely defined semantics, differing interpretations of specifications across different tools and the lack of a guarantee that a model transformation would generate a model that was compliant with its associated meta-model. To address these problems, two related solvers were developed to assist with realising the Systems MDD approach. The first solver, MMCS, is concerned with partial model completion, where a partial model is defined as a model that does not fully conform with its associated meta-model. It identifies appropriate modifications to be made to a partial model in order to bring it into full compliance. The second solver, TMPT, is a relational model transformation engine that prioritises target models. It considers multiple interpretations of a relational transformation specification, chooses an interpretation that results in a compliant target model (if one exists) and, optionally, maximises some other attribute associated with the model. A series of experiments were conducted that applied this to common transformation problems in the published literature

Event-B in the Institutional Framework: Defining a Semantics, Modularisation Constructs and Interoperability for a Specification Language

Event-B is an industrial-strength specification language for verifying the properties of a given system’s specification. It is supported by its Eclipse-based IDE, Rodin, and uses the process of refinement to model systems at different levels of abstraction. Although a mature formalism, Event-B has a number of limitations. In this thesis, we demonstrate that Event-B lacks formally defined modularisation constructs. Additionally, interoperability between Event-B and other formalisms has been achieved in an ad hoc manner. Moreover, although a formal language, Event-B does not have a formal semantics. We address each of these limitations in this thesis using the theory of institutions. The theory of institutions provides a category-theoretic way of representing a formalism. Formalisms that have been represented as institutions gain access to an array of generic specification-building operators that can be used to modularise specifications in a formalismindependent manner. In the theory of institutions, there are constructs (known as institution (co)morphisms) that provide us with the facility to create interoperability between formalisms in a mathematically sound way. The main contribution of this thesis is the definition of an institution for Event-B, EVT, which allows us to address its identified limitations. To this end, we formally define a translational semantics from Event- B to EVT. We show how specification-building operators can provide a unified set of modularisation constructs for Event-B. In fact, the institutional framework that we have incorporated Event-B into is more accommodating to modularisation than the current state-of-the-art for Rodin. Furthermore, we present institution morphisms that facilitate interoperability between the respective institutions for Event-B and UML. This approach is more generic than the current approach to interoperability for Event-B and in fact, allows access to any formalism or logic that has already been defined as an institution. Finally, by defining EVT, we have outlined the steps required in order to include similar formalisms into the institutional framework. Hence, this thesis acts as a template for defining an institution for a specification language

Action semantics of unified modeling language

The Uni ed Modeling Language or UML, as a visual and general purpose modeling language, has been around for more than a decade, gaining increasingly wide application and becoming the de-facto industrial standard for modeling software systems. However, the dynamic semantics of UML behaviours are only described in natural languages. Speci cation in natural languages inevitably involves vagueness, lacks reasonability and discourages mechanical language implementation. Such semi-formality of UML causes wide concern for researchers, including us. The formal semantics of UML demands more readability and extensibility due to its fast evolution and a wider range of users. Therefore we adopt Action Semantics (AS), mainly created by Peter Mosses, to formalize the dynamic semantics of UML, because AS can satisfy these needs advantageously compared to other frameworks. Instead of de ning UML directly, we design an action language, called ALx, and use it as the intermediary between a typical executable UML and its action semantics. ALx is highly heterogeneous, combining the features of Object Oriented Programming Languages, Object Query Languages, Model Description Languages and more complex behaviours like state machines. Adopting AS to formalize such a heterogeneous language is in turn of signi cance in exploring the adequacy and applicability of AS. In order to give assurance of the validity of the action semantics of ALx, a prototype ALx-to-Java translator is implemented, underpinned by our formal semantic description of the action language and using the Model Driven Approach (MDA). We argue that MDA is a feasible way of implementing this source-to-source language translator because the cornerstone of MDA, UML, is adequate to specify the static aspect of programming languages, and MDA provides executable transformation languages to model mapping rules between languages. We also construct a translator using a commonly-used conventional approach, in i which a tool is employed to generate the lexical scanner and the parser, and then other components including the type checker, symbol table constructor, intermediate representation producer and code generator, are coded manually. Then we compare the conventional approach with the MDA. The result shows that MDA has advantages over the conventional method in the aspect of code quality but is inferior to the latter in terms of system performance

A system development methodology for embedded applications

In recent years, Singapore’s manufacturing sector has contributed more than a quarter of the total Gross Domestic Product (GDP) and has established global leadership positions in several manufacturing areas such as electronics, Information Technology (IT) and industrial automation. The Singapore Economic Review Committee (ERC) recommendation states that “software and embedded systems that drive products are one of the most important technologies for the manufacturing sector. “ With the increasing adoption of automated and intelligent products, embedded systems have emerged as a crucial technology for Singapore. However, the development of embedded applications is not a trivial undertaking as it can usually involve multi-discipline parties and different application platforms. Most embedded application developments use either vendor specific or desktop based methodologies. Vendor specific methodologies constrain the company to rely on the specific vendor's solutions, whereas desktop-based methodologies are not well suited to embedded application development. Therefore, this research aims to develop a standard-based system development methodology for embedded applications. The research programme comprises 5 stages. The first stage reviews the existing system development methodologies for embedded applications. The next stage formulates the proposed conceptual methodology followed by the development of the proof-of-concept tool to demonstrate the merits of the proposed approach. The methodology is then tested and evaluated respectively by using industrial experiments and feedback from a workshop. The final stage refines the methodology based on the feedback and presents the final system development methodology. The research has provided a sound foundation which future research in methodology for embedded applications to develop further.Eng

A system development methodology for embedded applications

In recent years, Singapore’s manufacturing sector has contributed more than a quarter of the total Gross Domestic Product (GDP) and has established global leadership positions in several manufacturing areas such as electronics, Information Technology (IT) and industrial automation. The Singapore Economic Review Committee (ERC) recommendation states that “software and embedded systems that drive products are one of the most important technologies for the manufacturing sector. “ With the increasing adoption of automated and intelligent products, embedded systems have emerged as a crucial technology for Singapore. However, the development of embedded applications is not a trivial undertaking as it can usually involve multi-discipline parties and different application platforms. Most embedded application developments use either vendor specific or desktop based methodologies. Vendor specific methodologies constrain the company to rely on the specific vendor's solutions, whereas desktop-based methodologies are not well suited to embedded application development. Therefore, this research aims to develop a standard-based system development methodology for embedded applications. The research programme comprises 5 stages. The first stage reviews the existing system development methodologies for embedded applications. The next stage formulates the proposed conceptual methodology followed by the development of the proof-of-concept tool to demonstrate the merits of the proposed approach. The methodology is then tested and evaluated respectively by using industrial experiments and feedback from a workshop. The final stage refines the methodology based on the feedback and presents the final system development methodology. The research has provided a sound foundation which future research in methodology for embedded applications to develop further.Eng