SPEM 2.0 extension for pervasive information systems

Pervasive computing is a research field of computing technology that aims to achieve a new computing paradigm. In this paradigm, the physical environment has a high degree of pervasiveness and availability of computers and other information technology (IT) devices, usually with communication capabilities. Pervasive Information Systems (PIS), composed by these kinds of devices, bring issues that challenge software development for them. Model-Driven Development (MDD), strongly focusing and relying on models, has the potential to allow: the use of concepts closer to the domain and the reduction of semantic gaps; higher automation and lower dependency to technological changes; higher capture of expert knowledge and reuse; an overall increased productivity. Along with the focus and use of models, software development processes are fundamental to efficient development efforts of successful software systems. For the description of processes, Software & Systems Process Engineering Meta-Model Specification (SPEM) is the current standard specification published by the Object Management Group (OMG). This paper presents an extension to SPEM (version 2.0) Base Plug-In Profile that includes stereotypes needed to support a suitable structural process organization for MDD approaches aiming to develop software for PIS. A case study is provided to evaluate the applicability of the extension

Development framework pattern for pervasive information systems

During last decade, the world watched a social acceptance of computing and computers, enhanced information technology devices, wireless networks, and Internet; they gradually became a fundamental resource for individuals. Nowadays, people, organizations, and the environment are empowered by computing devices and systems; they depend on services offered by modern Pervasive Information Systems supported by complex software systems and technology. Research on software development for PIS-delivered information, on issues and challenges on software development for them, and several other contributions have been delivered. Among these contributions are a development framework for PIS, a profiling and framing structure approach, and a SPEM 2.0 extension. This chapter, revisiting these contributions, provides an additional contribution: a pattern to support the use of the development framework and profiling approach on software development for PIS. This contribution completes a first series of contributions for the development of PIS. This chapter also presents a case study that allowed demonstrating the applicability of these contribution

On the Performance Estimation and Resource Optimisation in Process Petri Nets

Many artificial systems can be modeled as discrete dynamic systems in which resources are shared among different tasks. The performance of such systems, which is usually a system requirement, heavily relies on the number and distribution of such resources. The goal of this paper is twofold: first, to design a technique to estimate the steady-state performance of a given system with shared resources, and second, to propose a heuristic strategy to distribute shared resources so that the system performance is enhanced as much as possible. The systems under consideration are assumed to be large systems, such as service-oriented architecture (SOA) systems, and modeled by a particular class of Petri nets (PNs) called process PNs. In order to avoid the state explosion problem inherent to discrete models, the proposed techniques make intensive use of linear programming (LP) problems

Implanted muon spin spectroscopy on 2-O-adamantane: a model system that mimics the liquid

The transition taking place between two metastable phases in 2-O-adamantane, namely the [Formula: see text] cubic, rotator phase and the lower temperature P21/c, Z  =  4 substitutionally disordered crystal is studied by means of muon spin rotation and relaxation techniques. Measurements carried out under zero, weak transverse and longitudinal fields reveal a temperature dependence of the relaxation parameters strikingly similar to those exhibited by structural glass[Formula: see text]liquid transitions (Bermejo et al 2004 Phys. Rev. B 70 214202; Cabrillo et al 2003 Phys. Rev. B 67 184201). The observed behaviour manifests itself as a square root singularity in the relaxation rates pointing towards some critical temperature which for amorphous systems is located some tens of degrees above that shown as the characteristic transition temperature if studied by thermodynamic means. The implications of such findings in the context of current theoretical approaches concerning the canonical liquid-glass transition are discussed.Postprint (author's final draft

Uncovering the spatial structure of mobility networks

The extraction of a clear and simple footprint of the structure of large, weighted and directed networks is a general problem that has many applications. An important example is given by origin-destination matrices which contain the complete information on commuting flows, but are difficult to analyze and compare. We propose here a versatile method which extracts a coarse-grained signature of mobility networks, under the form of a $2\times 2$ matrix that separates the flows into four categories. We apply this method to origin-destination matrices extracted from mobile phone data recorded in thirty-one Spanish cities. We show that these cities essentially differ by their proportion of two types of flows: integrated (between residential and employment hotspots) and random flows, whose importance increases with city size. Finally the method allows to determine categories of networks, and in the mobility case to classify cities according to their commuting structure.Comment: 10 pages, 5 figures +Supplementary informatio

From mobile phone data to the spatial structure of cities

Pervasive infrastructures, such as cell phone networks, enable to capture large amounts of human behavioral data but also provide information about the structure of cities and their dynamical properties. In this article, we focus on these last aspects by studying phone data recorded during 55 days in 31 Spanish metropolitan areas. We first define an urban dilatation index which measures how the average distance between individuals evolves during the day, allowing us to highlight different types of city structure. We then focus on hotspots, the most crowded places in the city. We propose a parameter free method to detect them and to test the robustness of our results. The number of these hotspots scales sublinearly with the population size, a result in agreement with previous theoretical arguments and measures on employment datasets. We study the lifetime of these hotspots and show in particular that the hierarchy of permanent ones, which constitute the "heart" of the city, is very stable whatever the size of the city. The spatial structure of these hotspots is also of interest and allows us to distinguish different categories of cities, from monocentric and "segregated" where the spatial distribution is very dependent on land use, to polycentric where the spatial mixing between land uses is much more important. These results point towards the possibility of a new, quantitative classification of cities using high resolution spatio-temporal data.Comment: 14 pages, 15 figure

Model-driven development for pervasive information systems

This chapter focus on design methodologies for pervasive information systems (PIS). It aims to contribute for the efficiency and effectiveness on software development of ubiquitous services/applications supported on pervasive information systems. Pervasive information systems are composed of conveniently orchestrated embedded or mobile computing devices that offer innovative ways to support existing and new business models. Those systems are characterized as having a potential large number of interactive heterogeneous embedded/mobile computing devices that collect, process, and communicate information. Additionally, they are target of high rates of technological innovations. Therefore, changes on requirements or in technology demands for frequent modifications on software at device and system levels. Software design and evolution for those requires suitable approaches that cope with such demands and characteristics of pervasive information systems. Model-driven development approaches (which essentially centre the focus of development on models, and involves concepts such as Platform-Independent Models, Platform-Specific Models, model transformations, and use of established standards) currently in research at academic and industrial arenas to design of large systems, offer potential benefits that can be applied to design and evolution of these pervasive information systems. In this chapter, we raise issues and propose strategies related to the software development of PIS using a model-driven development perspective

Model-driven methodologies for pervasive information systems development

This paper intends to introduce the concept of pervasive information systems (PIS) and the issues that arise from the software development for pervasive information systems. The model driven approach is generally described and its benefits to the software design are identified. Finally, some future directions for the usage of model driven methodologies within the development of PIS are highlighted, presenting some specific problems that nowadays that kind of methodologies have not yet been able to overcome

Model-driven software development for pervasive information systems implementation

Model-driven development (MDD) conceptions and techniques essentially centre the focus of development on models. They are subject of current research as they allow enhanced productivity, technological platform independence and longevity of software artifacts. Another area of current research is the ubiquitous/pervasive computing area. This field of computing research focuses on the widespread adoption of embedded or mobile heterogeneous computing devices, which, when properly orchestrated, globally compose pervasive information systems (PIS). This work intends to clarify how should be MDD concepts and techniques structurally consolidated into an approach to software development for PIS. It involves two projects as case studies. From these case studies, it will be proposed methodological insights to design approaches for software development of PIS. While clarifying several issues pertaining to MDD for PIS, it shall promote other research works based on issues needing further study

Sittin'On the Dock of the (WiFi) Bay: On the Frame Aggregation under IEEE 802.11 DCF

It is well known that frame aggregation in Internet communications improves transmission efficiency. However, it also causes a delay that for some real-time communications is inappropriate, thus creating a trade-off between efficiency and delay. In this paper, we establish the conditions for frame aggregation under the IEEE 802.11 DCF protocol to be beneficial on average delay. To do so, we first describe the transmission time in IEEE 802.11 in a stochastic framework and then we calculate the optimal value of the frames that, when aggregated, saves transmission time in the long term. Our findings, discussed with numerical experimentation, show that frame aggregation reduces transmission congestion and transmission delays