Rafael Timóteo de Sousa

Multi-dimensional model order selection

Multi-dimensional model order selection (MOS) techniques achieve an improved accuracy, reliability, and robustness, since they consider all dimensions jointly during the estimation of parameters. Additionally, from fundamental identifiability results of multi-dimensional decompositions, it is known that the number of main components can be larger when compared to matrix-based decompositions. In this article, we show how to use tensor calculus to extend matrix-based MOS schemes and we also present our proposed multi-dimensional model order selection scheme based on the closed-form PARAFAC algorithm, which is only applicable to multi-dimensional data. In general, as shown by means of simulations, the Probability of correct Detection (PoD) of our proposed multi-dimensional MOS schemes is much better than the PoD of matrix-based schemes.

Autonomic trust reasoning enables misbehavior detection in OLSR

Ad Hoc networks do not rely on any centralized administration or fixed network infrastructure and their nodes establish a routing structure in a self-organized way, by means of an ad hoc routing protocol such as OLSR. Ad hoc route discovery and maintenance introduce specific security problems for routing protocols to prevent, detect or respond. Solutions to secure these routing protocols using some centralized units or trusted third-parties actually constrain the self-organization of ad hoc networks. In this paper, we propose for OLSR the integration of trust reasonings into each node behavior, so as to allow a self-organized trust-based control to help nodes to detect misbehavior attacks. Our analysis of OLSR brings out the trust rules that characterize this protocol and allows us to express formally the trust-related properties that can be verified by each node to assess the correct behavior of the other nodes. Simulation of OLSR with nodes reasoning on trust allows us to demonstrate the effectiveness of our approach and to compare trust-based routing choices with the bare OLSR reachability-based choices.

A modular architecture for distributed IDS in MANET

In this paper we propose a distributed and modular architecture for an intrusion detection system (IDS) dedicated to a mobile ad hoc network (MANET) environment. The main feature of our proposition relies on the use, on each node of the MANET, of a local IDS (LIDS) cooperating with other LIDSes through the use of mobile agents. The modular design is needed as a response to the extensibility requirements related to the complex contexts of MANET. The proposed solution has been validated by a proof-of-concept prototype, which is described in the paper. Two different types of attacks are presented and have been implemented, at the network level and at the application level. The detection of such attacks are formally described by specification of data collection, attack signatures associated with such data and alerts generation, emphasizing the relation of each of these detection steps with the modules in the designed architecture. The use of the management information base (MIB) as a primary data source for the detection process is discussed and modules for MIB data extraction and processing are specified and implemented in the prototype. Experiments exhibit fairly good results, the attacks being collaboratively detected in real-time.

IoT architecture to enable intercommunication through REST API and UPnP using IP, ZigBee and arduino

To provide better life quality for mankind through the use of electrical and electronic devices that surround the world, controlling and communication between these equipments must occur and it must happen in an automatic and transparent way. This paper proposes a model based on usual technology to enable the event reading and the controlling of electrical devices, already existent and later developed, through a RESTful API or UPnP technology in order to allow the easy development of applications that can effectively improve life by transparent interaction with regular people. Furthermore, it will be proposed two direct applications of these APIs and it will be shown how to extend it.

Analysis of the implicit trust within the OLSR protocol

Trust is an interesting criterion for analyzing and comparing network protocols. The goal of this paper is to explicit the different types of trust relations between entities which exchange routing information and establish a routing infra-structure based on the OLSR protocol. One such entity assumes the other entities will behave in a particular way and the relations coming from this trust behavior are expressed in this paper using a formal language. This approach highlights the process of trust construction in OLSR and allows the analysis of trust requirements for this protocol, as well as the expression of attacks related to the betrayal of trust relations. Besides, this analysis allows the description of indicators for OLSR entities to have a protective mistrust behavior when effectively acting based on trust relations

Proposal of a secure, deployable and transparent middleware for Internet of Things

This paper proposes a security architecture for an IoT transparent middleware. Focused on bringing real life objects to the virtual realm, the proposed architecture is deployable and comprises protection measures based on existent technologies for security such as AES, TLS and oAuth. This way, privacy, authenticity, integrity and confidentiality on data exchange services are integrated to provide security for generated smart objects and for involved users and services in a reliable and deployable manner.

Secure Cooperative Half-Duplex Cognitive Radio Networks With

In this paper, we study the secrecy performance of a half-duplex cognitive relay network in the presence of multiple eavesdroppers and multiple primary users. In particular, generic

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-th Best Relay Selection

th best relay selection schemes for opportunistic relay selection (ORS) and partial relay selection (PRS) are proposed. Exact closed-form and asymptotic expressions for secrecy outage probability (SOP) of the considered schemes are derived. The outcome shows that ORS is able to achieve full secrecy diversity order while PRS obtains unit diversity order. Besides, the order of the selected relay is proved to affect the secrecy diversity order in the ORS scheme but not the PRS scheme, while the number of primary users does not have influence on the diversity order. Additionally, the significance of the change in the number of relays on the SOP enhances at higher orders of selected relay. Nevertheless, increasing the number of eavesdroppers reduces the secrecy diversity gain of the considered system in both schemes.

Ontologic audit trails mapping for detection of irregularities in payrolls

This paper proposes the usage of an ontology indexation process via concept maps to generate evidences of irregularities in payrolls. The proposal uses audit indicators as an instrument for documenting evidences as well as for tracking the data from the moment in which it is provided and structured. Hence, this proposal includes a methodology for transforming basic, and sometimes unstructured, payroll data into useful information for taking decisions regarding irregularities within the payroll auditing process. By means of its implementation as a business intelligence application, the proposal is validated using the original data generated in the monthly payroll analysis of the Brazilian public sector employees. This application was developed in order to assist the activities of the Public Management Secretariat (SEGEP), belonging to the Brazilian Ministry of Planning, Budget and Management (MP).