Consistency in Multi-Viewpoint Architectural Design of Enterprise Information Systems

Different stakeholders in the design of an enterprise information system have their own view on that design. To help produce a coherent design this paper presents a framework that aids in specifying relations between such views. To help produce a consistent design the framework also aids in specifying consistency rules that apply to the view relations and in checking the consistency according to those rules. The framework focuses on the higher levels of abstraction in a design, we refer to design at those levels of abstraction as architectural design. The highest level of abstraction that we consider is that of business process design and the lowest level is that of software component design. The contribution of our framework is that it provides a collection of basic concepts that is common to viewpoints in the area of enterprise information systems. These basic concepts aid in relating viewpoints by providing: (i) a common terminology that helps stakeholders to understand each others concepts; and (ii) a basis for defining re-usable consistency rules. In particular we define re-usable rules to check consistency between behavioural views that overlap or are a refinement of each other. We also present an architecture for a tool suite that supports our framework. We show that our framework can be applied, by performing a case study in which we specify the relations and consistency rules between the RM-ODP enterprise, computational and information viewpoints

Theoretical models and numerical methods for the study of sub-cellular phenomena

Nella presente tesi si discute sia la transizione di denaturazione del DNA che la dinamica enzimatica di Michaelis-Menten, introducendo entrambi gli argomenti partendo dalla loro importanza dal punto di vista di una migliore comprensione dei fenomeni intra-cellulari. Vengono quindi presentati i risultati originali ottenuti. Si è effettuata un'analisi approfondita di dati numerici su un modello disordinato di Poland-Scheraga per la transizione di denaturazione del DNA in cui l'effetto di auto-evitamento è tenuto correttamente in considerazione, nella quale: i) sono state introdotte delle appropriate pseudo-temperature critiche dipendenti dalla sequenza, il che ha permesso intanto di ottenere una stima rifinita dell'esponente che caratterizza il comportamento al punto critico disordinato, in accordo con una transizione di fase di ordine maggiore del secondo; ii) sulla base di questa analisi si è inoltre potuto caratterizzare il lento approccio all'equilibrio termodinamico osservato introducendo un'appropriata lunghezza di crossover, definita come la lunghezza delle sequenze al di sopra della quale l'effetto del disordine diviene evidente (sia dal comportamento delle varie osservabili mediate sulle sequenze, sia da quello in particolare del parametro d'ordine e della suscettività in circa la metà delle singole sequenze); iii) infine, si è descritto in dettaglio uno scenario fenomenologico nell'ambito del quale la lunghezza di crossover viene messa in relazione con i parametri del modello, e quindi, attraverso il calcolo combinatoriale della probabilità di ottenere una regione rara di lunghezza L in una sequenza di lunghezza N, si possono ottenere delle predizioni sul comportamento di taglia finita per diversi valori dei parametri. Nel caso della dinamica enzimatica di Michaelis Menten, si è portato a termine un dettagliato studio analitico, partendo dall'approssimazione standard di stato quasi-stazionario, che chiarisce le similitudini e le differenze tra l'approccio alternativo che si è introdotto, basato su tecniche di gruppo di rinormalizzazione, ed il metodo perturbativo che si è soliti applicare a sistemi ad effetto strato come quello considerato: i) in particolare, si è arrivati al secondo ordine nello sviluppo nel parametro appropriato, ottenendo corrispondentemente per la prima volta le soluzioni interne a quest'ordine, che non erano note in letteratura; ii) sulla base dell'analisi del comportamento delle approssimazioni uniformi così ottenute, alcune delle cui caratteristiche appaiono iterabili, si è potuto predire anche una parte del contributo a quest'ordine delle soluzioni esterne, quindi delle approssimazioni uniformi che riproducono il comportamento numerico delle soluzioni meglio di quelle note in una larga parte della finestra di tempo in cui svolge il fenomeno, anche in un caso studiato particolarmente sfavorevole sia dal punto di vista dei valori delle costanti cinetiche che di quello del parametro di espansione, tendendo inoltre correttamente a zero asintoticamente; iii) il metodo introdotto risulta quindi efficace, e le verifiche che sono state fatte dovrebbero permettere la sua futura applicazione intanto alla dinamica enzimatica di Michaelis Menten nell'ambito dell'approssimazione totale di stato quasi-stazionario

The Weak Gravity Conjecture and Scalar Fields

We propose a generalisation of the Weak Gravity Conjecture in the presence of scalar fields. The proposal is guided by properties of extremal black holes in ${\cal N}=2$ supergravity, but can be understood more generally in terms of forbidding towers of stable gravitationally bound states. It amounts to the statement that there must exist a particle on which the gauge force acts more strongly than gravity and the scalar forces combined. We also propose that the scalar force itself should act on this particle stronger than gravity. This implies that generically the mass of this particle decreases exponentially as a function of the scalar field expectation value for super-Planckian variations, which is behaviour predicted by the Refined Swampland Conjecture. In the context of ${\cal N}=2$ supergravity the Weak Gravity Conjecture bound can be tied to bounds on scalar field distances in field space. Guided by this, we present a general proof that for any linear combination of moduli in any Calabi-Yau compactification of string theory the proper field distance grows at best logarithmically with the moduli values for super-Planckian distances.Comment: 25 pages. v2: Modified and extended section 4.1. v3: Clarifications added, published versio

Combining goal-oriented and model-driven approaches to solve the Payment Problem Scenario

Motivated by the objective to provide an improved participation of business domain experts in the design of service-oriented integration solutions, we extend our previous work on using the COSMO methodology for service mediation by introducing a goal-oriented approach to requirements engineering. With this approach, business requirements including the motivations behind the mediation solution are better understood, specified, and aligned with their technical implementations. We use the Payment Problem Scenario of the SWS Challenge to illustrate the extension

Modular Composition of Language Features through Extensions of Semantic Language Models

Today, programming or specification languages are often extended in order to customize them for a particular application domain or to refine the language definition. The extension of a semantic model is often at the centre of such an extension. We will present a framework for linking basic and extended models. The example which we are going to use is the RSL concurrency model. The RAISE specification language RSL is a formal wide-spectrum specification language which integrates different features, such as state-basedness, concurrency and modules. The concurrency features of RSL are based on a refinement of a classical denotational model for process algebras. A modification was necessary to integrate state-based features into the basic model in order to meet requirements in the design of RSL. We will investigate this integration, formalising the relationship between the basic model and the adapted version in a rigorous way. The result will be a modular composition of the basic process model and new language features, such as state-based features or input/output. We will show general mechanisms for integration of new features into a language by extending language models in a structured, modular way. In particular, we will concentrate on the preservation of properties of the basic model in these extensions

Fluctuating diamagnetism in underdoped high temperature superconductors

The fluctuation induced diamagnetism of underdoped high temperature superconductors is studied in the framework of the Lawrence-Doniach model. By taking into account the fluctuations of the phase of the order parameter only, the latter reduces to a layered XY-model describing a liquid of vortices which can be either thermally excited or induced by the external magnetic field. The diamagnetic response is given by a current-current correlation function which is evaluated using the Coulomb gas analogy. Our results are then applied to recent measurements of fluctuation diamagnetism in underdoped YBCO. They allow to understand both the observed anomalous temperature dependence of the zero-field susceptibility and the two distinct regimes appearing in the magnetic field dependence of the magnetization.Comment: 12 pages, 4 figures included, accepted for publication in PR

Effect of the Gribov horizon on the Polyakov loop and vice versa

We consider finite temperature SU(2) gauge theory in the continuum formulation, which necessitates the choice of a gauge fixing. Choosing the Landau gauge, the existing gauge copies are taken into account by means of the Gribov-Zwanziger (GZ) quantization scheme, which entails the introduction of a dynamical mass scale (Gribov mass) directly influencing the Green functions of the theory. Here, we determine simultaneously the Polyakov loop (vacuum expectation value) and Gribov mass in terms of temperature, by minimizing the vacuum energy w.r.t. the Polyakov loop parameter and solving the Gribov gap equation. Inspired by the Casimir energy-style of computation, we illustrate the usage of Zeta function regularization in finite temperature calculations. Our main result is that the Gribov mass directly feels the deconfinement transition, visible from a cusp occurring at the same temperature where the Polyakov loop becomes nonzero. In this exploratory work we mainly restrict ourselves to the original Gribov-Zwanziger quantization procedure in order to illustrate the approach and the potential direct link between the vacuum structure of the theory (dynamical mass scales) and (de)confinement. We also present a first look at the critical temperature obtained from the Refined Gribov-Zwanziger approach. Finally, a particular problem for the pressure at low temperatures is reported.Comment: 19 pages, 8 .pdf figures. v2: extended section 3 + extra references; version accepted for publication in EPJ