CODEWEAVE: exploring fine-grained mobility of code

This paper is concerned with an abstract exploration of code mobility constructs designed for use in settings where the level of granularity associated with the mobile units exhibits significant variability. Units of mobility that are both finer and coarser grained than the unit of execution are examined. To accomplish this, we take the extreme view that every line of code and every variable declaration are potentially mobile, i.e., it may be duplicated or moved from one program context to another on the same host or across the network. We also assume that complex code assemblies may move with equal ease. The result is CODEWEAVE, a model that shows how to develop new forms of code mobility, assign them precise meaning, and facilitate formal verification of programs employing them. The design of CODEWEAVE relies greatly on Mobile UNITY, a notation and proof logic for mobile computing. Mobile UNITY offers a computational milieu for examining a wide range of constructs and semantic alternatives in a clean abstract setting, i.e., unconstrained by compilation and performance considerations traditionally associated with programming language design. Ultimately, the notation offered by CODEWEAVE is given exact semantic definition by means of a direct mapping to the underlying Mobile UNITY model. The abstract and formal treatment of code mobility offered by CODEWEAVE establishes a technical foundation for examining competing proposals and for subsequent integration of some of the mobility constructs both at the language level and within middleware for mobility

Reasoning About Context-Awareness in the Presence of Mobility

Context-awareness is emerging as an important computing paradigm designed to address the special needs of applications that must accommodate or exploit the highly dynamic environments that occur in the presence of physical or logical mobility. A number of formal models are available for reasoning about concurrency. Models designed to capture the specifics of mobility are fewer but still well represented (e.g., Mobile Ambients, π-Calculus, and Mobile UNITY). These models do not, however, provide constructs necessary for explicit modeling of context-aware interactions. This paper builds upon earlier efforts on state-based formal reasoning about mobility and explores the process by which a model such as Mobile UNITY can be transformed to explicitly capture context-awareness. Starting with an ex-amination of the essential features of context-aware systems, this paper explores a range of constructs designed to facilitate a highly decoupled style of programming among context-aware components. The result of this exploration is a model called Context UNITY

Reasoning About Context-Awareness in the Presence of Mobility

Context-awareness is emerging as an important computing paradigm designed to address the special needs of applications that must accommodate or exploit the highly dynamic environments that occur in the presence of physical or logical mobility. A number of formal models are available for reasoning about concurrency. Models designed to capture the specifics of mobility are fewer but still well represented (e.g., Mobile Ambients, π-Calculus, and Mobile UNITY). These models do not, however, provide constructs necessary for explicit modeling of context-aware interactions. This paper builds upon earlier efforts on state-based formal reasoning about mobility and explores the process by which a model such as Mobile UNITY can be transformed to explicitly capture context-awareness. Starting with an ex-amination of the essential features of context-aware systems, this paper explores a range of constructs designed to facilitate a highly decoupled style of programming among context-aware components. The result of this exploration is a model called Context UNITY

A Principled Exploration of Coordination Models

Coordination is a style of interaction in which information exchange among independent system components is accomplished by means of high-level constructs designed to enhance the degree of decoupling among participants. A de-coupled mode of computation is particularly important in the design of mobile systems which emerge dynamically through the composition of independently developed components meeting under unpredictable circumstances and thrust into achieving purposeful cooperative behaviors. This paper examines a range of coordination models tailored for use in mobile computing and shows that the constructs they provide are reducible to simple schema definitions in Mobile UNITY. Intellectually, this exercise contributes to achieving a better operational-level understanding of the relation among several important classes of models of mobility. Pragmatically, this work demonstrates the immediate applicability of Mobile UNITY to the formal specification of coordination constructs supporting mobile computing. Moreover, the resulting schemas are shown to be helpful in reducing the complexity of the formal verification effort

Supporting Context-Aware Application Development in Ad Hoc Mobile Networks

Some of the most dynamic systems being built today consist of physically mobile hosts and logically mobile agents. Such systems exhibit frequent configuration changes and a great deal of resource variability. Applications executing under these circumstances need to react continuously and rapidly to changes in operating conditions and must adapt their behavior accordingly. Applications with these capabilities are referred to as context-aware. Much of the current work on context-aware computing relies on information directly available to an application via context sensors on its local host, e.g., user profile, host location, time of day, resource availability, and quality of service measurements. The work reported in this dissertation starts by building a new perspective on context-awareness, in which the context includes, in principle, any information available in the ad hoc network but is restricted, in practice, to specific projections of the overall context. This work reports on the design and implementation of a middleware model that brings this notion of context to the application programmer. Another important aspect of the software engineering process is the ability to reason formally about the programs we create. This dissertation details initial steps to create formal reasoning mechanisms dedicated to the needs of context-aware applications. The results of this work simplify application development in ad hoc mobile networks from a design and implementation perspective and through formal reasoning

Mobile learning: benefits of augmented reality in geometry teaching

As a consequence of the technological advances and the widespread use of mobile devices to access information and communication in the last decades, mobile learning has become a spontaneous learning model, providing a more flexible and collaborative technology-based learning. Thus, mobile technologies can create new opportunities for enhancing the pupils’ learning experiences. This paper presents the development of a game to assist teaching and learning, aiming to help students acquire knowledge in the field of geometry. The game was intended to develop the following competences in primary school learners (8-10 years): a better visualization of geometric objects on a plane and in space; understanding of the properties of geometric solids; and familiarization with the vocabulary of geometry. Findings show that by using the game, students have improved around 35% the hits of correct responses to the classification and differentiation between edge, vertex and face in 3D solids.This research was supported by the Arts and Humanities Research Council Design Star CDT (AH/L503770/1), the Portuguese Foundation for Science and Technology (FCT) projects LARSyS (UID/EEA/50009/2013) and CIAC-Research Centre for Arts and Communication.info:eu-repo/semantics/publishedVersio

LIME: A Coordination Middleware Supporting Mobility of Agents and Hosts

LIME (Linda in a Mobile Environment) is a middleware supporting the development of applications that exhibit physical mobility of hosts, logical mobility of agents, or both. LIME adopts a coordination perspective inspired by work on the Linda model. The context for computation, represented in Linda by a globally accessible, persistent tuple space, is refined in LIME to transient sharing of identically-named tuple spaces carried by individual mobile units. Tuple spaces are also extended with a notion of location and programs are given the ability to react to specified states. The resulting model provides a minimalist set of abstractions that promise to facilitate rapid and dependable development of mobile applications. In this paper, we illustrate the model underlying LIME, provide a formal semantic characterization for the operations it makes available to the application developer, present its current design and implementation, and discuss lessons learned in developing applications that involve physical mobility

The Political Economy of Intergenerational Income Mobility

The intergenerational elasticity of income is considered one of the best measures of the degree to which a society gives equal opportunity to its members. While much research has been devoted to measuring this reduced-form parameter, less is known about its underlying structural determinants. Using a model with exogenous talent endowments, endogenous parental investment in children and endogenous redistributive institutions, we identify the structural parameters that govern the intergenerational elasticity of income. The model clarifies how the interaction between private and collective decisions determines the equilibrium level of social mobility. Two societies with similar economic and biological fundamentals may have vastly different degrees of intergenerational mobility depending on their political institutions. We offer empirical evidence in line with the predictions of the model. We conclude that international comparisons of intergenerational elasticity of income are not particularly informative about fairness without taking into account differences in politico-economic institutions.public education, intergenerational mobility, political institutions

Competition for Migrants in a Federation: Tax or Transfer Competition?

The paper provides an equilibrium analysis of how countries compete for migrants. The type of competition (tax or transfer competition) depends on whether the competing countries have similar policy preferences. With symmetric preferences, countries compete in taxes for migrants. With asymmetric preferences, migration competition takes place in income support levels. The results are robust to the degree of mobility and to whether high-income or low-income households are mobile. The results are relevant, e.g., for federal policies that tackle inefficient migration competition and for evaluating whether a country may wish to adopt unilateral ‘migration-purchase’ policies.migration, redistribution, income taxation, government strategy, endogenous type of competition

Virtual Reality Games for Motor Rehabilitation

This paper presents a fuzzy logic based method to track user satisfaction without the need for devices to monitor users physiological conditions. User satisfaction is the key to any product’s acceptance; computer applications and video games provide a unique opportunity to provide a tailored environment for each user to better suit their needs. We have implemented a non-adaptive fuzzy logic model of emotion, based on the emotional component of the Fuzzy Logic Adaptive Model of Emotion (FLAME) proposed by El-Nasr, to estimate player emotion in UnrealTournament 2004. In this paper we describe the implementation of this system and present the results of one of several play tests. Our research contradicts the current literature that suggests physiological measurements are needed. We show that it is possible to use a software only method to estimate user emotion