P ER VA SI V E computingPublished by the IEEE CS n 1536-1268/08/$25.00 © 2008 IEEE s o f t w a r e a r c h i t e c t u r e toward a General software infrastructure for ubiquitous computing This general software architecture is designed to support ubiquitous computing's fundamental challenges, helping the community develop and assess middleware and frameworks for this area. Cristiano André da Costa Federal University of Rio Grande do Sul Adenauer Corrêa Yamin Catholic University of Pelotas Cláudio Fernando Resin Geyer Federal University of Rio Grande do SulT he most profound technologies are those that disappear. They weave themselves into the fabric of everyday life until they are indistinguishable from it." 1 Mark Weiser's visionary statement summarizes what's expected from pervasive or ubiquitous computing (ubicomp): user access to the computational environment, everywhere and at all times, by means of any device. The difficulty lies in how to develop applications that will continually adapt to the environment and remain working as people move or change devices. 2 The more traditional mobility goal of providing computation "all the time, everywhere" 3 is considered a reactive approach to information access. However, it represents a proactive step toward ubicomp. For this purpose, we need a new class of software, but the limited number of languages and tools available still hinders this field's development. 4 Ubiquitous applications need middleware to interface between many different devices and end-user applications. 3 The aim is to hide environment complexity by isolating applications from the explicit management of protocols, distributed memory access, data replication, communication faults, and so on. Middleware can also solve heterogeneity problems related to architectures, operating systems, network technologies, and even programming languages, promoting their interoperation. On the other hand, a framework is an environment, comprising APIs, user interfaces, and tools, that simplifies software development and management in a specific domain. We can use frameworks to develop middleware and to build software that runs on that middleware.Our proposed general architectural model for ubicomp supports frameworks and middleware while considering all the challenges we believe significant in the field. Here, we highlight the numerous requirements that are essential to the area and that software infrastructure should cover. ubiquitous computing challengesPrevious studies present issues that are unique or still open in ubicomp (see the "Related Work in Ubiquitous Computing" sidebar). Table 1 summarizes the main issues.Heterogeneity is a concern derived from distributed systems. Ubicomp software must hide infrastructure differences from users and manage the required conversions from one environment to another, addressing protocol mismatches. In this scenario, developers using a device-independent approach have to create application logic only once. Another related issue inherited from distributed systems is scalabili...

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Wearable devices emerged from the advancement of communication technology and the miniaturization of electronic components. These devices periodically monitor the user's vital signs and generally have a short battery life. This work introduces ODIN, a model for optimized vital signs collection based on adaptive rules. Analyzing vital sign values requires preciseness, so the adaption of these collected data allows a personalized analysis of the user's health condition. The comparison with related works indicates that ODIN is the only model that presents context-aware-adaptive vital signs collection. The implementation of a prototype allowed to perform three evaluations of ODIN. The first evaluation used simulations in different scenarios, with the adaptive approach increasing battery life by 119% through the analysis of input data compared to data collection without adaptivity. The second evaluation applied the prototype to a database of real physiologic data, which allowed reduced data collection when the user has regular vital signs. This reduction optimized battery consumption by 66% compared to collection without adaptivity. Finally, the third evaluation applied ODIN through an Arduino and a heart rate monitor (Polar H7). The average power saved across mobile devices was 21%. Consequently, the adaptive strategy presented in this work allows the optimization of computational resources during the collection and analysis of vital signs. This optimization occurs because of the reduction in energy expenditure and the reduction in the amount of data that needs to be collected and stored.

The simulation of algorithms from quantum computing is currently the most affordable solution for development of new applications. Due to the high computational cost of such simulation, solutions towards novel features that increase the performance are always desired. This work proposes an extension for the D-GM's simulation framework, establishing the support for GPU-aware distributed quantum simulation. The project explores the concepts of heterogeneous computing, merging distributed and GPU computing in a single programming environment. Our results comprehend the distributed simulation of systems comprised by Hadamard transformations up to 21 qubits. Detailed analysis and a performance comparison between PyCUDA and JCUDA frameworks for our application are discussed. This work is a significant step towards the ultimate goal of our project, which is the hybrid simulation of quantum algorithms, i.e., exploring multi-core CPUs and GPUs distributed along a cluster, achieving scalability when larger systems are simulated.

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ISAM is a proposal directed to supporting physical and logical mobility, context-awareness, dynamic adaptation and the execution of large-scale distributed applications. In order to achieve its goals, ISAM uses, as strategy, an integrated environment that provides: (a) a programming language; (b) an execution environment; (c) a context recognition server. The integration is accomplished through an adaptation process that uses a multilevel collaborative model, in which both the system and the application contribute for that. In this paper we discuss the main components used to implement the ISAM features, and we also present a distributed application that explores some of this features.