Recent Publications

Campos JC, Ribeiro AN, Borges M.  2006.  A push infrastructure for mobile application deployment in mobile environments. Proceedings of the Conference on Mobile and Ubiquitous Systems (CMUS),. Abstractcsmu_mborges_rev2.pdf

Mobile devices tend to be a synonym of variety. Variety both in hardware capabilities and software act as restrictions to software development and deployment. Other restrictions arise from their condition of mobility, environmental conditions such as bandwidth, coverage availability, lighting and availability of services. In that perspective, this work intends to explore the possibility of a model of application deployment and execution that minimizes these issues - software gets pushed through an infrastructure and interaction between the user and the application is expected to have a behaviour between these two modes: purely client based and purely online based.
Debnath N, Garis A, Riesco D, Montejano G.  2006.  Defining Patterns Using UML Profiles. Proceedings of the IEEE International Conference on Computer Systems and Applications. 1-4244-0211-5:1147–1150. Abstractaiccsa06.pdf

Sometimes, UML is not enough expressive to describe patterns property. UML profiles allow extending UML syntax and semantic for modeling elements of particular domains. As profiles extend UML vocabulary, and design patterns define for designers a common vocabulary, so it is possible using profile for defining a pattern vocabulary in UML. Profiles can be used for solve particular problems in different domains. This work shows the way for defining design patterns with profile, proposing architecture in levels. It shows how the definition of a profile for a particular pattern is, and how an UML tool can be enough for introduce profile for patterns. It analyzes the advantages of using profiles to define, document, and visualize design patterns.
Corsini P, Masci P, Vecchio A.  2006.  Configuration and tuning of sensor network applications through virtual sensors. PerCom Workshops. :316–320. Abstract

Writing software for sensor networks requires full understanding of the physical phenomenon under observation. Nevertheless, in many cases knowing the details of the area of operation is difficult or unfeasible. This leads to the necessity of configuring and tuning the application executed on the sensor nodes even after the network has been deployed. We present a solution where a layer of computation is inserted between the application and the sensing equipment. This layer acts like a tiny interpreter and can be used to customize the behavior of already running applications. Experimental validation of the architecture and examples of use are also shown.
Corsini P, Masci P, Vecchio A.  2006.  VirtuS: a configurable layer for post-deployment adaptation of sensor network. ICWMC. :8. Abstract

Post-deployment adaptation of sensor networks is usually a necessity for several reasons, ranging from trivial deterioration of sensing hardware to unsatisfactory implementation of application logic. In this paper we present the architecture of VirtuS, a software component that can be incorporated into existing applications and remotely programmed to customize the behavior of sensor networks after deployment. Scenarios of use and experimental validation of the architecture are also included.
Avvenuti M, Corsini P, Masci P, Vecchio A.  2006.  Increasing the efficiency of preamble sampling protocols for wireless sensor networks. Proceedings of the First Mobile Computing and Wireless Communication International Conference, 2006. MCWC 2006.. :117–122. Abstract

Applications designed for event driven monitoring represent a challenging class of applications for wireless sensor networks. They are a special kind of monitoring applications, since they usually need low data rates, but also require mechanisms for low latency and asynchronous communication. In this paper we will focus on optimizations at the MAC layer that enable low energy consumption when contention-based protocols are adopted. We present B-MAC+, an enhanced version of a widely adopted MAC protocol, and we show that substantial improvements, in terms of network lifetime, can be reached over the original protocol.
Corsini P, Masci P, Vecchio A.  2006.  Experiences with the TinyOS Communication Library. Wireless Information Systems. :47-55. Abstract

TinyOS is a useful resource for developers of sensor networks. The operating system includes ready-made software components that enable rapid generation of complex software architectures. In this paper we describe the lessons gained from programming with the TinyOS communication library. In particular, we try to rationalize existing functionalities, and we present our solutions in the form of a communication library, called TComm-Lib.
Masci P.  2006.  Detecting data leakage in malicious Java applets. ReSIST Student Seminar. :81–84. Abstract

Web applets are programs dynamically loaded and executed inside the Internet browser of users' machine. They are used to extend the functionalities of web pages. Web applets can be associated with specific profiles granting access to information of users. As a consequence, web applets may possibly disclose, intentionally or by error, confidential information on public channels. We propose a technique to analyze the compiled code of web applets before execution. The technique is based on abstract interpretation. Data is associated with security levels and an iterative analysis is performed to trace information flows.
Preguiça N, Moreno CB, Martins JL, Shapiro M, Almeida PS, Domingos H, Fonte V, Duarte S, others.  2005.  Few: File management for portable devices. International Workshop on Software Support for Portable Storage (IWSSPS). Abstractfew-iwssps2005-final2.pdf

In recent years, an increasing number of portable devices with large amounts of storage have become widely used. In this paper, we present the early design of the FEW system, a system that aims to ease file management in the new mobile environment. To this end, the system will manage file replicas stored in fixed and portable storage devices. It will provide an automatic mechanism to establish new file replicas by analyzing file system activity. The system will automatically and incrementally synchronize all file replicas exploring the available network connectivity and the availability of portable storage devices. To merge concurrent updates, operational transformation techniques will be used.
Campos JC.  2005.  Model based web interfaces' analysis. HCI International 2005 - 11th International Conference on Human-Computer Interaction (posters section). Abstract0fcfd508e7e264007c000000.pdf

Tools exist that look at the usability of sites from a static perspective – for example, looking for broken links. Other tools analyse web server's logs to understand how users behave when using the site. While these tools are helpful, they can only be applied after development and deployment. This paper investigates how a model checking based approach can be applied to web sites' design to reason about their behavioral properties from the early stages of development. The goal is that analysis of possible interactions between users and a site might be performed before actual development and deployment of the site.
Campos JC, Fernandes A.  2005.  Testing AudioBrowser. HCI International - 11th International Conference on Human-Computer Interaction (posters section). Abstracthciint05-ab_af.pdf

We are developing AudioBrowser, a browser for visually impaired users. This paper presents a usability analysis study that was carried out on the first version of the browser. Due to the lack of availability of visually impaired users not involved with the tool's design, we had to resort to simulate a visual impaired situation with regular sighted users. Although this may seem unrealistic we believe that this is actually a worst case scenario.The problems identified during this study are described, and proposals for the next version of the tool are put forward.

Mano A, Campos JC.  2005.  A study on usability criteria regarding interfaces for children. Interact 2005 Workshop on Child Computer Interaction: Methodological Research. :32-35. Abstractinteract05-kids.pdf

Building an application's interface is always an attempt to match the software functions with the users' mental model. This task is complicated enough when an adult is designing the interface to other adults. When the users are children, the challenge is harder still. How can the users' mental model be predicted? This communication deals with a study that aims to answer this question, going from the characteristics of the children cognitive thought to the discovery of efficient design guidelines for interfaces.
Teixeira L, Costa Ó, Pereira V, Leão CP, Soares F, Restivo M, Chouzal F, Mendes J, Campos JC.  2005.  Laboratórios virtuais: duas aplicações no ensino de engenharia. 7º Simpósio Internacional de Informática Educativa – SIIE. Abstractp479-teixeira.pdf

Este projecto insere-se no âmbito dos estágios curriculares de final de curso da licenciatura em Matemática e Ciências de Computação da Universidade do Minho e da disciplina de Laboratório de Automação do 5ºano da licenciatura de Engenharia Mecânica Faculdade de Engenharia da Universidade do Porto. O trabalho proposto, numa base de ensino/aprendizagem colaborativo e multidisciplinar, assenta também na prática assistido por projecto. Este projecto consiste no desenvolvimento de objectos de aprendizagem através da construção e disponibilização de simuladores e conteúdos de suporte em ambiente Web. Foram desenvolvidas aplicações baseadas em sistemas reais: medição e controlo do nível de um sistema de tanques em circuito fechado e medição da deformação de uma estrutura. Visa, também, a implementação dos sistemas experimentais, respectiva sensorização, actuação e controlo para integração num projecto de Laboratórios Remotos . Os Laboratórios Virtuais e os Laboratórios Remotos têm sido alvo de particular atenção no âmbito do ensino a distância, como meio complementar ao ensino tradicional ou na sua utilização integrada em redes de parceiros partilhando as capacidades laboratoriais distintas de diferentes instituições.

Barbosa MB, Farshim P.  2005.  Efficient Identity-Based Key Encapsulation to Multiple Parties. 10th IMA International Conference on Cryptography and Coding . 3796:428-441. Abstractmidkem.pdf

We introduce the concept of identity based key encapsulation to multiple parties (mID-KEM), and define a security model for it. This concept is the identity based analogue of public key KEM to multiple parties. We also analyse possible mID-KEM constructions, and propose an efficient scheme based on bilinear pairings. We prove our scheme secure in the random oracle model under the Gap Bilinear Diffie-Hellman assumption.
Barbosa MB, Page D.  2005.  On the Automatic Construction of Indistinguishable Operations. 10th IMA International Conference on Cryptography and Coding . 3796:233-247. Abstractpaper_2.pdf

An increasingly important design constraint for software running on ubiquitous computing devices is security, particularly against physical methods such as side-channel attack. One well studied methodology for defending against such attacks is the concept of indistinguishable functions which leak no information about program control flow since all execution paths are computationally identical. However, constructing such functions by hand becomes laborious and error prone as their complexity increases. We investigate techniques for automating this process and find that effective solutions can be constructed with only minor amounts of computational effort.
Soares L, Pereira JO.  2005.  Experimental Performability Evaluation of Middleware for Large-Scale Distributed Systems. 7th International Workshop on Performability Modeling of Computer and Communication Systems - PMCCS. Abstractminhassf-pmccs05_jop.pdf

We present a tool for experimental evaluation of distributed software that enables performability tests to be incorporated in the agile development of complex middleware systems. The proposed approach combines simulation with the profiling of key components and is achieved by an extension to a standard simulation kernel and reflection, thus leveraging existing simulation models and easing the integration of existing components. The evaluation of database replication middleware in large-scale systems is used to illustrate the approach.