Jorge A. Perez - FCT New University of Lisbon

Jorge A. Perez
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Name
Jorge A. Perez
Affiliation
FCT New University of Lisbon
City
Lisbon
Country
Portugal

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Computer Science - Logic in Computer Science (14)
 
Computer Science - Programming Languages (12)
 
Computer Science - Databases (3)
 
Computer Science - Cryptography and Security (3)
 
Computer Science - Distributed; Parallel; and Cluster Computing (2)
 
Computer Science - Learning (2)
 
Computer Science - Data Structures and Algorithms (1)
 
Computer Science - Computers and Society (1)

Publications Authored By Jorge A. Perez

Under a reversible semantics, computation steps can be undone. This paper addresses the integration of reversible semantics into process languages for communication-centric systems, equipped with behavioral types. In prior work, we introduced a monitors-as-memories approach to seamlessly integrate reversible semantics into a process model in which concurrency is governed by session types (a class of behavioral types), covering binary (two-party) protocols with synchronous communications. Read More

Intruders detection in computer networks has some deficiencies from machine learning approach, given by the nature of the application. The principal problem is the modest display of detection systems based on learning algorithms under the constraints imposed by real environments. This article focuses on the machine learning approach for network intrusion detection in batch and data stream environments. Read More

Data mining has been widely used to identify potential customers for a new product or service. In this article is done a study of previous work relating to the application of data mining methodologies for software projects, specifically for direct marketing projects. Several data sets of demographic and historical customer purchases data available for evaluation of algorithms in this area, some of them very new and current are described. Read More

Network intrusion detection is one of the most visible uses for Big Data analytics. One of the main problems in this application is the constant rise of new attacks. This scenario, characterized by the fact that not enough labeled examples are available for the new classes of attacks is hardly addressed by traditional machine learning approaches. Read More

2016Jun
Affiliations: 1IMT School for Advanced Studies Lucca, Italy, 2University of Groningen, The Netherlands

Much research has studied foundations for correct and reliable communication-centric systems. A salient approach to correctness uses session types to enforce structured communications; a recent approach to reliability uses reversible actions as a way of reacting to unanticipated events or failures. This note develops a simple observation: the machinery required to define asynchronous semantics and monitoring can also support reversible protocols. Read More

With the massive data challenges nowadays and the rapid growing of technology, stream mining has recently received considerable attention. To address the large number of scenarios in which this phenomenon manifests itself suitable tools are required in various research fields. Instance-based data stream algorithms generally employ the Euclidean distance for the classification task underlying this problem. Read More

This volume contains the proceedings of DCM 2015, the 11th International Workshop on Developments in Computational Models held on October 28, 2015 in Cali, Colombia. DCM 2015 was organized as a one-day satellite event of the 12th International Colloquium on Theoretical Aspects of Computing (ICTAC 2015). Several new models of computation have emerged in the last few years, and many developments of traditional computational models have been proposed with the aim of taking into account the new demands of computer systems users and the new capabilities of computation engines. Read More

2016Feb
Affiliations: 1University of Novi Sad, Serbia, 2University of Novi Sad, Serbia, 3University of Novi Sad, Serbia, 4University of Groningen, The Netherlands, 5IMT Institute for Advanced Studies Lucca, Italy

Security requirements in distributed software systems are inherently dynamic. In the case of authorization policies, resources are meant to be accessed only by authorized parties, but the authorization to access a resource may be dynamically granted/yielded. We describe ongoing work on a model for specifying communication and dynamic authorization handling. Read More

Today's software systems are highly distributed and interconnected, and they increasingly rely on communication to achieve their goals; due to their societal importance, security and trustworthiness are crucial aspects for the correctness of these systems. Behavioural types, which extend data types by describing also the structured behaviour of programs, are a widely studied approach to the enforcement of correctness properties in communicating systems. This paper offers a unified overview of proposals based on behavioural types which are aimed at the analysis of security properties. Read More

2015Aug
Affiliations: 1University of Glasgow, United Kingdom, 2University of Groningen, The Netherlands

Besides respecting prescribed protocols, communication-centric systems should never "get stuck". This requirement has been expressed by liveness properties such as progress or (dead)lock freedom. Several typing disciplines that ensure these properties for mobile processes have been proposed. Read More

2015Aug
Affiliations: 1University of Novi Sad, Serbia, 2University of Novi Sad, Serbia, 3University of Groningen, The Netherlands

We compare mechanisms for compensation handling and dynamic update in calculi for concurrency. These mechanisms are increasingly relevant in the specification of reliable communicating systems. Compensations and updates are intuitively similar: both specify how the behavior of a concurrent system changes at runtime in response to an exceptional event. Read More

The Web of Linked Data is composed of tons of RDF documents interlinked to each other forming a huge repository of distributed semantic data. Effectively querying this distributed data source is an important open problem in the Semantic Web area. In this paper, we propose LDQL, a declarative language to query Linked Data on the Web. Read More

This work proposes tractable bisimulations for the higher-order pi-calculus with session primitives (HOpi) and offers a complete study of the expressivity of its most significant subcalculi. First we develop three typed bisimulations, which are shown to coincide with contextual equivalence. These characterisations demonstrate that observing as inputs only a specific finite set of higher-order values (which inhabit session types) suffices to reason about HOp} processes. Read More

2014Aug
Affiliations: 1Univerzitet u Novom Sadu, Serbia, 2Univerzitet u Novom Sadu, Serbia, 3Univerzitet u Novom Sadu, Serbia, 4University of Groningen, The Netherlands, 5LaSIGE, Faculdade de Ciências, Universidade de Lisboa, Portugal

Protocol specifications often identify the roles involved in communications. In multiparty protocols that involve task delegation it is often useful to consider settings in which different sites may act on behalf of a single role. It is then crucial to control the roles that the different parties are authorized to represent, including the case in which role authorizations are determined only at runtime. Read More

We present initial results on a comprehensive model of structured communications, in which self- adaptation and security concerns are jointly addressed. More specifically, we propose a model of self-adaptive, multiparty communications with secure information flow guarantees. In this model, security violations occur when processes attempt to read or write messages of inappropriate security levels within directed exchanges. Read More

Relating the specification of the global communication behavior of a distributed system and the specifications of the local communication behavior of each of its nodes/peers (e.g., to check if the former is realizable by the latter under some safety and/or liveness conditions) is a challenging problem addressed in many relevant scenarios. Read More

Grid computing (GC) systems are large-scale virtual machines, built upon a massive pool of resources (processing time, storage, software) that often span multiple distributed domains. Concurrent users interact with the grid by adding new tasks; the grid is expected to assign resources to tasks in a fair, trustworthy way. These distinctive features of GC systems make their specification and verification a challenging issue. Read More

In recent work, we have developed a session types discipline for a calculus that features the usual constructs for session establishment and communication, but also two novel constructs that enable communicating processes to be stopped, duplicated, or discarded at runtime. The aim is to understand whether known techniques for the static analysis of structured communications scale up to the challenging context of context-aware, adaptable distributed systems, in which disciplined interaction and runtime adaptation are intertwined concerns. In this short note, we summarize the main features of our session-typed framework with runtime adaptation, and recall its basic correctness properties. Read More

2012Oct
Affiliations: 1University of Bologna, 2INRIA Rhone Alpes, 3FCT New University of Lisbon, 4University of Bologna

We propose the concept of adaptable processes as a way of overcoming the limitations that process calculi have for describing patterns of dynamic process evolution. Such patterns rely on direct ways of controlling the behavior and location of running processes, and so they are at the heart of the adaptation capabilities present in many modern concurrent systems. Adaptable processes have a location and are sensible to actions of dynamic update at runtime; this allows to express a wide range of evolvability patterns for concurrent processes. Read More

2010Feb
Affiliations: 1IT University of Copenhagen, 2École Polytechnique - Universidad Javeriana Cali, 3University of Bologna

We present a unified framework for the declarative analysis of structured communications. By relying on a (timed) concurrent constraint programming language, we show that in addition to the usual operational techniques from process calculi, the analysis of structured communications can elegantly exploit logic-based reasoning techniques. We introduce a declarative interpretation of the language for structured communications proposed by Honda, Vasconcelos, and Kubo. Read More

In the recent years, a lot of attention has been paid to the development of solid foundations for the composition and inversion of schema mappings. In this paper, we review the proposals for the semantics of these crucial operators. For each of these proposals, we concentrate on the three following problems: the definition of the semantics of the operator, the language needed to express the operator, and the algorithmic issues associated to the problem of computing the operator. Read More

SPARQL is the W3C candidate recommendation query language for RDF. In this paper we address systematically the formal study of SPARQL, concentrating in its graph pattern facility. We consider for this study a fragment without literals and a simple version of filters which encompasses all the main issues yet is simple to formalize. Read More