João Coelho Garcia

Instituto Superior Técnico · Computer Science and Engineering

This work proposes a new privacy-enhancing system that minimizes the disclosure of information in error reports. Error reporting mechanisms are of the utmost importance to correct software bugs but, unfortunately, the transmission of an error report may reveal users’ private information. Some privacy-enhancing systems for error reporting have been...

Abstract—Failure detection plays a central role in the engineering of distributed systems. Furthermore, many applications have timing constraints and require failure detectors that pro-vide quality of service (QoS) with some quantitative timeliness guarantees. Therefore, they need failure detectors that are fast and accurate.We introduce the Two Wi...

Software testing is often unable to detect all program flaws. These bugs are most commonly reported to programmers in error reports containing core dumps and/or execution traces that frequently reveal users' private information without providing all necessary informa-tion for effective debugging. Hence, these mechanisms are sparsely used due to use...

Wireless communications are one of the technical problems that must be addressed by cooperative robot teams. The wireless medium often becomes heavily loaded and the robots may take too long to successfully transmit information, resulting in outdated shared data or failures in cooperative behaviors that require synchronization among teammates. This...

Most computer applications are published with bugs, whose reproducibility is strictly dependent on the availabil-ity of detailed information about the real usage of the application. Unfortunately, this data collection process raises severe privacy issues, as error reports are very likely to include personal information. This represents a strong dis...

This chapter describes a novel approach to Grid and overlay network research that leverages distributed infrastructures and multi-core machines enabling increased simulation complexity and speed. We present its motivation, background, current shortcomings, and the core architectural concepts of the novel research proposed. This is an ongoing effort...

Optimistic replication is a fundamental technique for sup- porting concurrent work practices in mobile environments. However, due to sudden and frequent transitions to weakly connected situations, user experience when accessing repli- cated data is poor and discourages users from using the repli- cation service. While most research on optimistic re...

We describe COGITARE, a novel approach to grid and over-lay network research leveraging distributed infrastructures and multi-core machines for increased simulation complexity and speed. We present its motivation, background, current shortcomings and the core architectural concepts of the novel research proposed. This is an on-going effort to furth...

Computer mobility allows people to use computers in varied and changing environments. This variability forces applications to adapt thus requiring awareness of the computational and physical environment (e.g. information about power management, network connections, synchronization opportunities, storage, computation, location-based services, etc.)....

Computer mobility has the potential to let users take advantage of computers in new, varied and changing environments. Applications would be able to do much more for the user (e.g. providing hints concerning power management, network connection establishment, synchronization opportunities, update propagation, location-based services, etc.) if they...

Distributed cooperative engineering applications require consistent and long-term sharing of large volumes of data, which may cause conflicts due to concurrent read/write operations. Therefore designing concurrency control for underlying middleware systems is a difficult issue.Current transactional solutions, even if based on an optimistic approach...

This paper proposes a new approach to building a virtual enterprise (VE) software infrastructure that offers persistence, concurrent access, coherence and security on a distributed datastore based on the distributed shared-memory paradigm. The platform presented, persistent distributed store (PerDiS), is demonstrated with test applications that sho...

The need for sharing is well-known in a large number of distributed collaborative applications. These applications are difficult to develop for an environment in which network connections are slow and not reliable.For this purpose, we developed a platform called OBIWAN that: i) allows the application programmer to decide the mechanism by which obje...

Parallel operating systems are the interface between parallel computers (or computer systems) and the applications (parallel or not) that are executed on them. They translate the hardware’s capabilities into concepts usable by programming languages. Great diversity marked the beginning of parallel architectures and their operating systems. This div...

The PerDiS (Persistent Distributed Store) project addresses the issue of providing support for distributed collaborative engineering applications. We describe the design and implementation of the PerDiS platform, and its support for such applications. Collaborative engineering raises system issues related to the sharing of large volumes of fine-gra...

In this paper, we propose a new approach to build Virtual Enterprise software infrastructure that offers persistence, concurrent access, coherence and security on a distributed-shared data store based on distributed-shared memory paradigm.

In this paper, we propose a new approach to build a Virtual Enterprise software infrastructure that offers persistence, concurrent access, coherence and security on a distributed-shared data store based on distributed-shared memory paradigm.

Companies cooperating in the framework of a virtual enterprise have increasing demands for systems on which to base applications for their particular environment: groups of workers on distant independent LANs. In this paper, we present a transactional file system for a distributed persistent store designed to support cooperative engineering applica...

We present the design for a fault-tolerant persistent data storage in a wide-area distributed cooperative engineering environment. We discuss some of the current options in file system design and, in particular, the relation between file mobility and transaction protocols. We believe that file mobility, and consequently coherence protocols, global...

There has been research on syntactic level extensions to the Common Object Request Broker (CORBA) Interface Definition Language (IDL) in order to obtain persistence for CORBA application objects (e.g. CORBA Persistent Object Service). The purpose of this paper is to present an implementation of the CORBA POS, which provides efficient persistence an...