The precision of formal specifications allows us to prove program correctness. Even if formal methods are not used throughout the software project, formalisation improves our understanding of the problem. Formal specifications are amenable to automated analysis and consistency checking. However using them is challenging. Customers do not understand formal notations. Specifiers have difficulty tackling large problems. Once systems are built, formal specifications quickly become outdated during software maintenance. A method of developing formal specifications using concrete scenarios is proposed to tackle the disadvantages just mentioned. A concrete scenario describes system behaviour with successive steps. The pre- and post-states of scenario steps are expressed with actual data rather than variables. Concrete scenarios are expressed in a natural language or formal notation. They increase customer involvement in the creation of formal specifications. Scenarios may be ranked by priorities allowing specifiers to focus on a small part of the system. Formal specifications are constructed incrementally. New requirements are also captured in concrete scenarios which guide the modification of formal specifications. On one hand, concrete scenarios assist the creation and maintenance of formal specifications. On the other hand, they facilitate program correctness proofs without using conventional formal specifications. This is achieved by adding implementation details to customer scenarios. The resulting developer scenarios, encapsulating decisions of data structures and algorithms, are generalised to operation schemas. With the implementation details, the schemas written in formal notations are programs rather than specifications.

The first Part of the thesis explains from first principles the concept of "logic programming" and its practical application in the programming language Prolog. Prolog is a simple but powerful language which encourages rapid, error-free programming and clear, readable, concise programs. The basic computational mechanism is a pattern matching process ("unification") operating on general record structures ("terms" of logic). IThe ideas are illustrated by describing in detail one sizable Prolog program which implements a simple compiler. The advantages and practicability of using Prolog for "real" compiler implementation are discussed. The second Part of the thesis describes techniques for implementing Prolog efficiently. In particular it is shown how to compile the patterns involved in the matching process into instructions of a low-level language. This idea has actually been implemented in a compiler (written in Prolog) from Prolog to DECsystem-10 assembly language. However the principles involved are explained more abstractly in terms of a "Prolog Machine". The code generated is comparable in speed with that produced by existing DEC10 Lisp compilers. Comparison is possible since pure Lisp can be viewed as a (rather restricted) subset of Prolog. It is argued that structured data objects, such as lists and trees, can be manipulated by pattern matching using a "structure 'sharing" representation as efficiently as by conventional selector and constructor functions operating on linked records in "heap" storage. Moreover the pattern matching formulation actually helps the implementor to produce a better implementation.

Conditions under which compositions of component systems form a well-defined system-of-systems are here formulated at a fundamental level. Statement of what defines a well-defined composition and sufficient conditions guaranteeing such a result offers insight into exemplars that can be found in special cases such as differential equation and discrete event systems. For any given global state of a composition, two requirements can be stated informally as: (1) the system can leave this state, i.e., there is at least one trajectory defined that starts from the state; and (2) the trajectory evolves over time without getting stuck at a point in time. Considered for every global state, these conditions determine whether the resultant is a well-defined system and, if so, whether it is non-deterministic or deterministic. We formulate these questions within the framework of iterative specifications for mathematical system models that are shown to be behaviorally equivalent to the Discrete Event System Specification (DEVS) formalism. This formalization supports definitions and proofs of the afore-mentioned conditions. Implications are drawn at the fundamental level of existence where the emergence of a system from an assemblage of components can be characterized. We focus on systems with feedback coupling where existence and uniqueness of solutions is problematic.

As optical designs become more sophisticated and incorporate aspheric and free form surfaces, the need to specify limits on mid-spatial frequency manufacturing errors becomes more critical, particularly as we better understand the effects of these errors on image quality. While there already exist methods based on Fourier analysis to specify these errors in most commercial interferometry software, the method of calculation and the power spectral density (PSD) results remain obscure to many in the optical design and manufacturing field. We suggest that the structure functions (SF) contains the same information as in the Fourier based PSD but in a way that is much more transparent to analysis, interpretation and application as a specification. The units of measure are more familiar and the concept behind the analysis is simpler to understand. Further, the information contained in the structure function (or PSD) allows a complete specification of an optical surface from the finest measurable detail of roughness to the overall figure. We discuss the origin of the structure function in the field of astronomy to describe the effects of air turbulence on image quality, the simple mathematical definition of the structure function and its easy means of calculation and how its results should be scaled depending on the location of the optical surface in a system from pupil to image plane. Finally, we give an example of how to write a specification of an optical surface using the structure function.

Introduction: Despite rapid developments across multiple areas of research and practice, an organizational-level theory of Crowdsourcing has yet to emerge. Objectives: Therefore, this thesis has two major objectives; 1) specify the boundaries, constructs, and relationships of an organizational-level theory of Crowdsourcing, and 2) begin the theoretical validation process by operationalizing the theory for new exploratory, explanatory, and conceptual research. Methods: In respect to the first objective, an organizational-level theory of Crowdsourcing is created through inductive processes based upon observations of the real-world, and the extant organizational literature. In respect to the second objective, a mixed-methods research design is implemented to present three separate studies that use the theoretical perspective as a lens to operationalize new exploratory, explanatory, and conceptual Crowdsourcing research. Results: The Crowd Capital perspective is introduced, and defines three new constructs for the Crowdsourcing research; Dispersed Knowledge, Crowd Capability, and Crowd Capital. Crowd Capital theory is shown to be a valid theoretical contribution in the management research by illustrating the perspective’s incremental originality and scientific utility. Conclusion: The thesis develops and validates an organizational-level theory explaining how and why organizations implement Crowdsourcing, and through the exploratory and explanatory operationalizations of the Crowd Capital perspective, this work contributes to the empirical knowledge-base in the Crowdsourcing research. Further, this thesis contributes methodologically by illustrating and implementing a mixed-methods research design for theory validation in the Crowdsourcing research, while also supplying managers and executives with detailed guidance on the trade-offs inherent to the different modalities of Crowdsourcing. Thesis Organization: This thesis is organized in a monograph format comprised of eight chapters; 1) Introduction, 2) Literature review, 3) Theoretical model, 4) Methodology, 5) Exploratory research, 6) Explanatory research, 7) Conceptual research, and 8) Conclusion. As an outcome of this thesis, three journal articles and five conference proceedings have been accepted in peer-reviewed outlets1, and the author has been awarded a mini-track about Crowdsourcing at one of the most prestigious conferences in the field. The articles and the conference mini-track details are listed in Appendix A & B at the end of the dissertation.

Development of the nervous system is a highly organized process that utilizes genetic mechanisms conserved across the animal kingdom. Components of the nervous system such as inhibitory GABAergic neural networks are common among most multicellular animals. The nematode Caenorhabditis elegans, utilizes similar genetic pathways to that of mice and humans to develop its GABAergic neural networks. These GABAergic neural networks are composed of two types of GABAergic motor neurons: the VD and DD sub-classes. The GABAergic differentiation of both these sub-classes requires the conserved transcription factor, Pitx/UNC-30. The VD sub-class is differentiated from the DD motor neurons by the expression of another transcription factor, COUP TFII/UNC-55. The transcriptional mechanisms regulating the expression of Pitx/UNC-30 and Coup TFII are unknown. We sought to determine how Pitx/UNC-30 and COUP TF-II/UNC-55 were transcriptionally regulated in an attempt to understand how mechanisms of GABAergic fate specification and class specification may be connected. We hypothesized there would be different mechanisms regulating the GABAergic differentiation and sub-class specification of the two sub-classes of GABAergic motor neurons. To test this, we dissected the transcriptional mechanisms responsible for the expression of Pitx/UNC-30 and COUP TFII/UNC-55. We found that different isoforms of the Hox cofactor Meis/UNC-62 stabilize and activate the expression of UNC-55. Furthermore, we conclude that Pitx/UNC-30 expression is regulated differently between the two motor neuron sub-classes by Meis/UNC-62, Hox-B7/MAB-5 and NeuroD/CND-1, each of which are vital to the development of different components of the nervous system in vertebrates. Our findings suggest that the GABAergic identity and the sub-class specification of neurons are under the control of multiple conserved transcription factors responsible for neuron fate determination and post mitotic identities.

Characterization of the effect of physical properties on the performance such as stiffness and drainage of unbound granular materials is necessary in order to incorporate them in pavement design. The stiffness, deformation and permeability behaviour of unbound granular materials are the essential design inputs for Mechanistic-Empirical Pavement Design Guide as well as empirical design methods. The performance based specifications are aimed to design, and construct a durable and cost effective material throughout the design life of a pavement. However, the specification varies among jurisdiction depending on the historical or current practice, locally available materials, landform, climate and drainage. A literature review on the current unbound granular materials virgin and recycled concrete aggregate base construction specification has been carried out in this study. Resilient modulus, permanent deformation and permeability tests have been carried out on seven gradations of materials from locally available sources. Resilient modulus stiffness of unbound granular material at two different conditioning stress level have been compared in the study. The long term deformation behaviour has also been characterized from results of the permanent deformation test using shakedown approach, dissipated energy approach and a simplified approach. The results show improvement in resilient modulus and permanent deformation for the proposed specification compared to the currently used materials as a results of reduced fines content, increased crush count and inclusion of larger maximum aggregate size into the gradation. A significant effect of particle packing on permeability of granular materials have also been found, in addition to the effect of fines. / October 2016

Le travail présenté dans cette thèse est une contribution aux méthodes formelles de spécification et de vérification. Les spécifications formelles sont utilisées pour décrire un logiciel, ou plus généralement un système, d'une manière mathématique sans ambiguïté. Des techniques de vérification formelle sont définies sur la base de ces spécifications afin d'assurer l'exactitude d'un système donné. Cependant, les méthodes formelles ne sont souvent pas pratiques et facile à utiliser dans des systèmes réels. L'une des raisons est que de nombreux formalismes de spécification ne sont pas assez riches pour couvrir à la fois les exigences orientées données et orientées comportement. Certains langages de spécification ont été proposés pour couvrir ce genre d'exigences. Le langage Circus se distingue parmi ces langues par une syntaxe et une sémantique riche et complètement intégrées.L'objectif de cette thèse est de fournir un cadre formel pour la spécification et la vérification de systèmes complexes. Les spécifications sont écrites en Circus et la vérification est effectuée soit par des tests ou par des preuves de théorèmes. Des environnements similaires de spécification et de vérification ont déjà été proposés dans la littérature. Une spécificité de notre approche est de combiner des preuves de théorème avec la génération de test. En outre, la plupart des méthodes de génération de tests sont basés sur une caractérisation syntaxique des langages étudiés. Notre environnement est différent car il est basé sur la sémantique dénotationnelle et opérationnelle de Circus. L'assistant de preuves Isabelle/HOL constitue la plateforme formelle au-dessus de laquelle nous avons construit notre environnement de spécification et de vérification.La première contribution principale de notre travail est l'environnement formel de spécification et de preuve Isabelle/Circus, basé sur la sémantique dénotationnelle de Circus. Sur la base d’Isabelle/HOL nous avons fourni une intégration vérifiée d’UTP, la base de la sémantique de Circus. Cette intégration est utilisée pour formaliser la sémantique dénotationnelle du langage Circus. L'environnement Isabelle/Circus associe à cette sémantique des outils de parsing qui aident à écrire des spécifications Circus. Le support de preuve d’Isabelle/HOL peut être utilisé directement pour raisonner sur ces spécifications grâce à la représentation superficielle de la sémantique (shallow embedding). Nous présentons une application de l'environnement à des preuves de raffinement sur des processus Circus (impliquant à la fois des données et des aspects comportementaux).La deuxième contribution est l'environnement de test CirTA construit au-dessus d’Isabelle/Circus. Cet environnement fournit deux tactiques de génération de tests symboliques qui permettent la vérification de deux notions de raffinement: l'inclusion des traces et la réduction de blocages. L'environnement est basé sur une formalisation symbolique de la sémantique opérationnelle de Circus avec Isabelle/Circus. Plusieurs définitions symboliques et tactiques de génération de test sont définies dans le cadre de CirTA. L'infrastructure formelle permet de représenter explicitement les théories de test ainsi que les hypothèses de sélection de test. Des techniques de preuve et de calculs symboliques sont la base des tactiques de génération de test. L'environnement de génération de test a été utilisé dans une étude de cas pour tester un système existant de contrôle de message. Une spécification du système est écrite en Circus, et est utilisé pour générer des tests pour les deux relations de conformité définies pour Circus. Les tests sont ensuite compilés sous forme de méthodes de test JUnit qui sont ensuite exécutées sur une implémentation Java du système étudié. / The work presented in this thesis is a contribution to formal specification and verification methods. Formal specifications are used to describe a software, or more generally a system, in a mathematical unambiguous way. Formal verification techniques are defined on the basis of these specifications to ensure the correctness of the resulting system. However, formal methods are often not convenient and easy to use in real system developments. One of the reasons is that many specification formalisms are not rich enough to cover both data-oriented and behavioral requirements. Some specification languages were proposed to cover this kind of requirements. The Circus language distinguishes itself among these languages by a rich syntax and a fully integrated semantics.The aim of this thesis is to provide a formal environment for specifying and verifying complex systems. Specifications are written in Circus and verification is performed either by testing or by theorem proving. Similar specifications and verification environment have already been proposed. A specificity of our approach is to combine supports for proofs and test generation. Moreover, most test generation methods are based on a syntactic characterization of the studied languages. Our proposed environment is different since it is based on the denotational and operational semantics of Circus. The Isabelle/HOL theorem prover is the formal platform on top of which we built our specification and verification environment.The first main contribution of our work is the Isabelle/Circus specification and proof environment based on the denotational semantics of Circus. On top of Isabelle/HOL we provide a machine-checked shallow embedding of UTP, the semantics basis of Circus. This embedding is used to formalize the denotational semantics of the Circus language. The Isabelle/Circus environment associates to this semantics some parsing facilities that help writing Circus specifications. The proof support of Isabelle/HOL can be used directly to reason on these specifications thanks to the shallow embedding of the semantics. We present an application of the environment to refinement proofs on Circus processes (involving both data and behavioral aspects). The second main contribution is the CirTA testing framework build on top of Isabelle/Circus. The framework provides two symbolic test generation tactics that allow checking two notions of refinement: traces inclusion and deadlocks reduction. The framework is based on a shallow symbolic formalization of the operational semantics of Circus using Isabelle/Circus. Several symbolic definition and test generation tactics are defined in the CirTA framework. The formal infrastructure allows us to represent explicitly test theories as well as test selection hypothesis. Proof techniques and symbolic computations are the basis of test generation tactics. The test generation environment was used for a case study to test an existing message monitoring system. A specification of the system is written in Circus, and used to generate tests following the defined conformance relations. The tests are then compiled in forms of JUnit test methods and executed against a Java implementation of the monitoring system.This thesis is a step towards, on one hand, the development of sophisticated testing tools making use of proof techniques and, on the other hand, the integration of testing and proving within formally verified software developments.

Master of Science / Department of Computing and Information Sciences / John Hatcliff / With the increase in development of safety and security critical systems, it is important to have more sophisticated methods for engineering such systems. It can be difficult to understand and verify critical properties of these systems because of their ever growing size and complexity. Even a small error in a complex system may result in casualty or significant monetary loss. Consequently, there is a rise in the demand for scalable and accurate techniques to enable faster development and verification of high assurance systems. This thesis focuses on discovering dependencies between various parts of a system and leveraging that knowledge to infer information flow properties and to verify security policies specified for the system. The primary contribution of this thesis is a technique to build dependence graphs for languages which feature abstraction and refinement. Inter-procedural slicing and inter-procedural chopping are the techniques used to analyze the properties of the system statically. The approach outlined in this thesis provides a domain-specific language to query the information flow properties and to specify security policies for a critical system. The spec- ified policies can then be verified using existing static analysis techniques. All the above contributions are integrated with a development environment used to develop the critical system. The resulting software development tool helps programmers develop, infer, and verify safety and security systems in a single unified environment.

Um novo modelo para a especificação de hiperdocumentos denominado HMBS - Hyperdocument Model Based on Statecharts - é proposto. O HMBS adota como modelo formal subjacente a técnica Statecharts, cuja estrutura e semântica operacional são utilizadas para especificar a estrutura organizacional e a semântica de navegação de hiperdocumentos grandes e complexos. A definição do HMBS, bem como a semântica de navegação adotada, são apresentadas. Na definição apresenta-se como o modelo permite separar as informações referentes a estrutura organizacional e navegacional das representações físicas do hiperdocumento. Também são discutidas características do modelo que possibilitam ao autor analisar a estrutura do hiperdocumento, encorajando a especificação de hiperdocumentos estruturados. Para provar e validar a viabilidade prática do uso do HMBS num contexto real foi desenvolvido um ambiente de autoria e navegação de hiperdocumentos denominado HySCharts - Hyperdocumenf System based on Statecharts. Esse ambiente fornece facilidades de prototipação rápida e simulação interativa de hiperdocumentos. Para ilustrar como o modelo HMBS e o HySCharts podem ser utilizados no contexto de uma abordagem de projeto sistemática é utilizada como estudo de caso a especificação de um hiperdocumento que apresenta o Parque Ecológico de São Carlos / A new model for hyperdocument specification called HMBS - Hyperdocument Model Based on Statecharts - is proposed. HMBS uses the Statechart formalism as its underlying model. Statecharts structure and operational semantics are used to specify the organizational structure and the browsing semantics of large and complex hyperdocuments. The definition of HMBS is presented and its browsing semantics is described. It is shown how the model allows the separation of information related to the organizational and navigational structure from the hyperdocument\'s physical representation. Model features that allow authors to analyze the hyperdocument structure, encouraging the specification of structured hyperdocuments are also discussed. As a proof of concept and also to evaluate the feasibility of using HMBS in real-life applications a system called HySCharts - Hyperdocument System based on StateCharts - was developed. HySCharts is composed by an authoring and a browsing environments, supporting rapid prototyping and interactive simulation of hyperdocuments. A case study is presented that uses the specification of a hyperdocument introducing the Ecological Park of São Carlos to illustrate the use of HMBS and of the HySCharts environment integrated into a systematic design approach