Antônio Tadeu A. Gomes

Network anomaly detection using nonextensive entropy

Detection is a crucial step towards efficiently diagnosing network traffic anomalies within an autonomous system (AS). We propose the adoption of nonextensive entropy - a one-parameter generalization of Shannon entropy - to detect anomalies in network traffic within an AS. Experimental results show that our approach based on nonextensive entropy outperforms previous ones based on classical entropy while providing enhanced flexibility, which is enabled by the possibility of fine-tuning the sensitivity of the detection mechanism.

DICHOTOMY: A Resource Discovery and Scheduling Protocol for Multihop Ad hoc Mobile Grids

There has been a good amount of research over the past few years on the integration of mobile devices into computational grids. Little of it, however, has addressed the more challenging issue of dynamically establishing spontaneous, multihop ad hoc mobile grids, and then only in preliminary form. In such grids, resource discovery and scheduling have been traditionally approached separately in the literature. In our view, this is an inappropriate dichotomy as regards multihop ad hoc mobile grids. In this paper, we propose a resource discovery and scheduling protocol for mobility (DICHOTOMY), which allows resource provisioning to be scheduled among the most resourceful nodes in the mobile grid, while mitigating the overhead of discovery messages exchanged among them. Our experimental results in a testbed and in a simulation platform show that the protocol provides efficient load balancing between nodes under an increasing number of requests, and scales well with respect to an increasing number of nodes in comparison with traditional broadcast-based solutions for service discovery.

NETKIT: a software component-based approach to programmable networking

While there has already been significant research in support of openness and programmability in networks, this paper argues that there remains a need for generic support for the integrated development, deployment and management of programmable networking software. We further argue that this support should explicitly address the management of run-time reconfiguration of systems, and should be independent of any particular programming paradigm (e.g. active networking or open signaling), programming language, or hardware/ operating system platform. In line with these aims, we outline an approach to the structuring of programmable networking software in terms of a ubiquitously applied software component model that can accommodate all levels of a programmable networking system from low-level system support, to in-band packet handling, to active networking execution environments to signaling and coordination.

Modeling QoS provision on adaptable communication environments

This paper proposes an approach for representing and programming QoS functions in communication systems. It presents a model that gives adequate support for defining: (i) communication environments and their adaptation mechanisms, and (ii) frameworks that delineate QoS-specific abstractions that appear within any communication environment.

Towards a ubiquitous healthcare system for acute myocardial infarction patients in Brazil

After an acute myocardial infarction (AMI), the sooner the patient is approached, the greater are the chances that pharmacological therapy (using thrombolytics) be more effective than surgical intervention. Nevertheless, the thrombolytic therapy may have hazard effects on AMI patients that present any contraindication to it. As a consequence, paramedics usually hesitate about applying the thrombolytic therapy - preferring to immediately transfer patients to coronary care units (CCUs) - unless cardiologists support their decision. To cope with this scenario, we envision a ubiquitous telemedicine system for supporting cardiologists and paramedics in (i) the remote decision upon the eligibility of AMI patients to the thrombolytic therapy and (ii) the remote monitoring of patients being transferred, so-called In this paper, we present AToMS (AMI teleconsultation & monitoring), a system that makes extensive use of (possibly heterogeneous) wireless communication technology to allow its use by a paramedic at the location where the AMI patient is first assisted, thus reducing the delay between the onset of symptoms and the eventual application of proper treatment. All exchanged messages among paramedics and cardiologists are recorded, thus rendering a fully auditable system

Intra-domain IP traceback using OSPF

Denial of service (DoS) attacks are a serious threat to the appropriate operation of services within network domains. In this paper, we propose a system that creates an overlay network to provide intra-domain IP traceback to deal with this threat. The Main contribution of our proposal with respect to previous work is its ability to provide partial and progressive deployment of the traceback system throughout a monitored network domain. We build the overlay network using the OSPF routing protocol through the creation of an IP Traceback Opaque LSA (Link State Advertisement). We also investigate and evaluate the performance of partial and progressive deployment of the proposed system, showing its suitability even for large network domains.

Mitigating Reply Implosions in Query-Based Service Discovery Protocols for Mobile Wireless Ad Hoc Networks

Providing service discovery in an efficient and scalable way in ad hoc networks is a challenging problem, in particular for multihop scenarios, due to the large number of potential participant nodes and the scarce resources in these networks. In this paper, we propose and evaluate an approach to mitigate the reply implosion problem in query-based service discovery protocols for multihop mobile ad hoc networks. Our simulation results show the scalability and efficiency of the proposed solution. We demonstrate that the proposed scheme considerably reduces the number of transmissions without compromising the efficiency of the service discovery in scenarios of pedestrian mobility.

Experiences of the Brazilian national high‐performance computing network on the rapid prototyping of science gateways

Arguably, an important amount of scientific software development time is likely to be employed on user interfaces. In particular, science gateways have gained increasing interest from the e‐Science community. These gateways allow hiding the complexity of the underlying resources that give support to the management of scientific data and to the execution of scientific applications. Based on our previous experience with the development of science gateways for diverse application domains in the Brazilian national high‐performance computing network (SINAPAD), we have devised a rapid prototyping strategy to lower the barrier for scientific application developers to launch new science gateways. This strategy is based on two main tools. The first tool implements a gateway engine that can be configured by a small set of XML files. Such files completely define the desired functionality of a specific science gateway in the gateway engine. The gateway engine also offers other features not commonly found in related technologies, such as file sharing, data provenance tracking, and restricted anonymous access to underlying computational resources. The second tool implements both an editor and a packager for the aforementioned engine. This tool allows the developer to rapidly deploy and launch a new science gateway in ordinary Web application containers. In this paper, we present our results with the use of both tools in the SINAPAD network. We also discuss about the current limitations of both tools, as well as how we have been dealing with such limitations to provide a more comprehensive toolset to developers. Copyright

Rapid prototyping of active measurement tools

We propose a platform for the rapid prototyping of active measurement tools to collect network characteristics. Our proposal, named FLAME (Flexible Lightweight Active Measurement Environment), allows the prototyping of active measurement tools that depend or not on cooperative destination nodes. FLAME provides its users with basic active measurement primitives-corresponding to basic building blocks-upon which sophisticated active measurement tools can be prototyped quickly, practically, and efficiently through scripts in the Lua scripting language. This platform is based on the distributed deployment of measurement agents in some network nodes. These agents can send and receive probes in response to Lua scripts sent by a user console. Such agents also publish the measurement data in a standardized way in a repository that a central manager keeps, thus simplifying the management and analysis of such data. We validate the FLAME platform as well as show its flexibility and accuracy through experiments on a local testbed and also on Planet-lab. We also evaluate the proposed platform as compared to previous work in terms of the easing of development due to prototype scripting as well as the achieved memory footprint. In conclusion, we discuss different possibilities for further developments built upon the basic functionality of the proposed platform.

Performance evaluation of a discovery and scheduling protocol for multihop ad hoc mobile grids

Despite the many research efforts addressing the integration of mobile nodes into grids, only a few of them have considered the establishment of mobile grids over wireless ad hoc networks (hereafter,mobile ad hoc grids). Clearly, such grids need specialized resource discovery and scheduling mechanisms. To the best of our knowledge, though, the research on these mechanisms for mobile ad hoc grids is still preliminary. Besides, and more importantly, it has approached discovery and scheduling as separate mechanisms, which, we argue, is not suitable for mobile ad hoc grids. In this paper, we propose the integration of resource discovery and scheduling for mobile ad hoc grids into a single protocol called DICHOTOMY (Discovery and sCHeduling prOTOcol for MobilitY). This protocol allows computational tasks to be distributed appropriately in a mobile ad hoc grid, while mitigating the overhead of discovery messages exchanged among the nodes. Our experiments show that the protocol: (i) does proper scheduling, allowing an efficient load balancing among the nodes and helping with lowering the average completion time of tasks; (ii) keeps the discovery efficiency at acceptable levels in mobility scenarios and (iii) scales very well with respect to an increasing number of nodes, both in the total amount of energy savings due to packet transmissions and the distribution of such savings among the nodes.