Pedro Salgueiro

Using constraints for intrusion detection: the NeMODe system

In this work we present NeMODe a declarative system for Computer Network Intrusion detection which provides a declarative Domain Specific Language for describing computer network intrusion signatures that could spread across several network packets, which allows to state constraints over network packets, describing relations between several packets, and providing several back-end detection mechanisms which relies on Constraint Programming (CP) methodologies to find those intrusions.

A DSL for intrusion detection based on constraint programming

Intrusion Detection Systems (IDS) are increasingly important in computer networks, allowing the early diagnosis and detection of anomalous situations, which could otherwise put network performance at risk or even compromise the security or integrity of user data. In this work we present NeMODe, a domain specific language for network intrusion detection that allows to describe network intrusions that spread across several network packets, relying on Constraint Programming(CP), a programming methodology that starts with a declarative description of the desirable network situations and, based on that description, a set of parameterizations for network intrusion detection mechanisms will execute to find those intrusions.

Network monitoring with constraint programming: preliminary specification and analysis

Network Monitoring and Intrusion Detection Systems plays an important role in todays computer networks health, allowing the diagnosis and detection of anomalous situations on the network that could damage the performance and put the security of users data in risk if not detected or diagnosed in time to take any necessary measures. In this paper we present a preliminary specification and analysis of a network monitoring and intrusion detection concept system based on constraint programming, implemented on several constraint solver systems. This concept allows to describe the desirable network situations through constraints on network entities, allowing a more expressive and clear way of describing network situations.

University of Évora in QA@CLEF-2004

The approach followed by the University of Evora team when building a system for participation in the CLEF 2004 question answering task for Portuguese is described. The system is based on two steps: for each question, a first search selects a set of potentially relevant documents; each of these documents is then analysed to obtain a semantic representation and the answer to the initial query. This approach was applied to the QA@CLEF test set for Portuguese with interesting results that have allowed us to identify the strong and weak features of our system.

A distribution-oriented approach to support landscape connectivity for ecologically distinct bird species

Managing landscape connectivity is a widely recognized overarching strategy for conserving biodiversity in human-impacted landscapes. However, planning the conservation and management of landscape connectivity of multiple and ecologically distinct species is still challenging. Here we provide a spatially-explicit framework which identifies and prioritizes connectivity conservation and restoration actions for species with distinct habitat affinities. Specifically, our study system comprised three groups of common bird species, forest-specialists, farmland-specialists, and generalists, populating a highly heterogeneous agricultural countryside in the southwestern Iberian Peninsula. We first performed a comprehensive analysis of the environmental variables underlying the distributional patterns of each bird species to reveal generalities in their guild-specific responses to landscape structure. Then, we identified sites which could be considered pivotal in maintaining current levels of landscape connectivity for the three bird guilds simultaneously, as well as the number and location of sites that need to be restored to maximize connectivity levels. Interestingly, we found that a small number of sites defined the shortest connectivity paths for the three bird guilds simultaneously, and were therefore considered key for conservation. Moreover, an even smaller number of sites were identified as critical to expand the landscape connectivity at maximum for the regional bird assemblage as a whole. Our spatially-explicit framework can provide valuable decision-making support to conservation practitioners aiming to identify key connectivity and restoration sites, a particularly urgent task in rapidly changing landscapes such as agroecosystems.

Modelling distributed network attacks with constraints

NeMODe is a declarative system for computer network intrusion detection, providing a declarative domain specific language for describing network intrusion signatures which can span several network packets, by stating constraints over network packets, describing relations between several packets in a declarative and expressive way. It provides several back-end detection mechanisms, all based on a constraint programming framework, to perform the detection of the desired signatures. In this work, we demonstrate how to model and perform the detection of distributed network attacks using each of the detection mechanisms provided by NeMODe, based in Gecode, adaptive search and MiniSat to perform the detection of the specific intrusions. We also use the sliding network traffic window version of the adaptive search back-end detection mechanism to simulate live network traffic and evaluate the performance of the system in conditions near to real life networks.

Bird Collisions in a Railway Crossing a Wetland of International Importance (Sado Estuary, Portugal)

Many studies have evaluated bird mortality in relation to roads and other human structures, but little is known about the potential impacts of railways. In particular, it is uncertain whether railways are an important mortality source when crossing wetlands heavily used by aquatic birds. Here we analyze bird collisions in a railway that crosses the Nature Reserve of the Sado Estuary (Portugal) over an annual cycle, documenting bird mortality and the flight behaviour of aquatic birds in relation to a bowstring bridge. During monthly surveys conducted on 16.3 km of railway, we found 5.8 dead birds/km/10 survey days in the section crossing wetland habitats (6.3 km), while <0.5 dead birds/km/10 survey days were found in two sections crossing only forested habitats. Most birds recorded were small songbirds (Passeriformes), while there was only a small number of aquatic birds (common moorhen, mallard, flamingo, great cormorant, gulls) and other non-passerines associated with wetlands (white stork). During nearly 400 h of observations, we recorded 27,000 movements of aquatic birds across the Sado bridge, particularly in autumn and winter. However, only <1% of movements were within the area of collision risk with trains, while about 91% were above the collision risk area, and 8% were below the bridge. Overall, our case study suggests that bird collisions may be far more numerous in railways crossing wetland habitats than elsewhere, although the risk to aquatic birds may be relatively low. Information from additional study systems would be required to evaluate whether our conclusions apply to other wetlands and railway lines.

An interactive web-based tool for breast reduction surgery simulation

In this work, we present a 3D web-based interactive tool for numerical modeling and simulation approach to breast reduction surgery simulation, to assist surgeons in planning all aspects related to breast reduction surgery before the actual procedure takes place, thereby avoiding unnecessary risks. In particular, it allows the modeling of the initial breast geometry, the definition of all aspects related to the surgery and the visualization of the post-surgery breast shape in a realistic environment.