Discrete-time dynamic modeling for software and services composition as an extension of the Markov chain approach

Discrete Time Markov Chains (DTMCs) and Continuous Time Markov Chains (CTMCs) are often used to model various types of phenomena, such as, for example, the behavior of software products. In that case, Markov chains are widely used to describe possible time-varying behavior of “self-adaptive” software systems, where the transition from one state to another represents alternative choices at the software code level, taken according to a certain probability distribution. From a control-theoretical standpoint, some of these probabilities can be interpreted as control signals and others can just be observed. However, the translation between a DTMC or CTMC model and a corresponding first principle model, that can be used to design a control system is not immediate. This paper investigates a possible solution for translating a CTMC model into a dynamic system, with focus on the control of computing systems components. Notice that DTMC models can be translated as well, providing additional information

A compositional method for reliability analysis of workflows affected by multiple failure modes

We focus on reliability analysis for systems designed as workflow based compositions of components. Components are characterized by their failure profiles, which take into account possible multiple failure modes. A compositional calculus is provided to evaluate the failure profile of a composite system, given failure profiles of the components. The calculus is described as a syntax-driven procedure that synthesizes a workflows failure profile. The method is viewed as a design-time aid that can help software engineers reason about systems reliability in the early stage of development. A simple case study is presented to illustrate the proposed approach

Concetto e Sistema in Kant. Immaginazione Trascendentale ed Unità della Ragione.

La tesi affronta le tematiche relative all'immaginazione trascenrdentale all'interno delle due edizioni della deduzione trascendentale dei concetti puri dell'intelletto ed in riferimento al capitolo sullo schematismo nella Critica della region pura di Kant. Scopo del lavoro è cogliere le differenti funzioni dell'immaginazione e valutare in base ad esse l'intero equilibrio teorico della deduzione come momento di attuazione del progetto sistematico della Ragione. Pensando lo schematismo come un esigenza sistematica vedremo in che misura l'immaginazione svolga un ruolo per determinare l'unità della Ragione nella sua stessa articolazione in facoltà

The attitude – behaviour gap in eWOM: the paradoxical Generation Z

This paper exploits bigdata to explore to what extent Generation Z customers engage in discussing sustainability practices carried out by their service providers when posting a review online. The study identifies the attention Gen Z pays to the environmental and social domains of sustainability, including trend over time and their association with ratings (i.e. customer satisfaction). Text analytics with a specific dictionary developed for the study of sustainability are applied on a dataset of 500.000 hotel reviews, covering six European cities and 10 years. Results reveal how, despite Gen Z is portrayed as the most socially and environmentally conscious generation, often bringing sustainability into their consumption practices, the story is rather different with regards to their discourse online. Gen Z tend to discuss fewer on sustainable practices comparing to other generational cohorts, while the social and environmental dimensions are differently associated with their ratings

On the probabilistic symbolic analysis of programs

Recently we have proposed symbolic execution techniques for the probabilistic analysis of programs. These techniques seek to quan- tify the probability of a program to satisfy a property of interest under a relevant usage profile. We describe recent advances in prob- abilistic symbolic analysis including handling of complex floating- point constraints and nondeterminism, and the use of statistical techniques for increased scalability

The how and why of consumers' co-creation: evidence from the Fiat 500 case study

In the current business environment firms need to continuously renew their products to keep up with their competitive advantage. Increasingly, customers' needs are atomized and they change at an unprecedented pace. Thus, some companies have started to tap consumer knowledge over the internet. These companies are using the web and social media to build virtual spaces to connect with actual and potential customers in order to engage them at different stages of the new product development process. In such virtual spaces, consumers spontaneously decide to contribute with their knowledge, ideas and activities to company's cocreation initiatives. In marketing research, there is a dearth of studies on how companies are involving ordinary consumers in their innovation processes through internet applications. Moreover, few studies have investigated the implications of cocreation activities on innovation outputs and brand image. Thus, this study has adopted a single case study approach and has explored the how and why of cocreation in the Fiat 500 open innovation project (‘500 wants you'), and the results achieved in terms of innovation generated and impact on the corporate brand image

Caterina, Alexa and the Others

What will the future identity of design be? Perhaps that of making man-machine communication even more fluid through the development of more intuitive interfaces and objects that prolong us, capable of inducing the emotion of non-reality or on the contrary will tend to restore strength to the material, to the tangible aspects and to the real emotions? Artificial intelligence is meaningless, it cannot therefore give sense or meaning to what it learns, so the strategic vision of design will remain a human responsibility just as creativity will always belong to that side of the human, that artificial intelligence cannot understand and undermine. We can therefore conclude that yes, probably in future, many works will be carried out by robots, but still instructed by man.2n

Iterative test suites refinement for elastic computing systems

Elastic computing systems can dynamically scale to continuously and cost-effectively provide their required Quality of Service in face of time-varying workloads, and they are usually implemented in the cloud. Despite their wide-spread adoption by industry, a formal definition of elasticity and suitable procedures for its assessment and verification are still missing. Both academia and industry are trying to adapt established testing procedures for functional and non-functional properties, with limited effectiveness with respect to elasticity. In this paper we propose a new methodology to automatically generate test-suites for testing the elastic properties of systems. Elasticity, plasticity, and oscillations are first formalized through a convenient behavioral abstraction of the elastic system and then used to drive an iterative test suite refinement process. The outcomes of our approach are a test suite tailored to the violation of elasticity properties and a human-readable abstraction of the system behavior to further support diagnosis and fix