Predictive Power Control of Grid and Rotor Side converters in Doubly Fed Induction Generators Based Wind Turbine

This paper presents a new control scheme for grid and rotor side for doubly fed induction generator (DFIG) using model based predictive control. The control strategy minimizes quality functions, which represent the desired behavior of the converter. The technique developed uses predictive direct power control to control the rotor and grid side converter. The main advantages of this method are no need of linear controllers, coordinates transformations or modulators for converter and inverter. Simulation results demonstrate robust, precise, and fast dynamic behavior of system

Predictive Power Control of Grid and Rotor Side converters in Doubly Fed Induction Generators Based Wind Turbine

This paper presents a new control scheme for grid and rotor side for doubly fed induction generator (DFIG) using model based predictive control. The control strategy minimizes quality functions, which represent the desired behavior of the converter. The technique developed uses predictive direct power control to control the rotor and grid side converter. The main advantages of this method are no need of linear controllers, coordinates transformations or modulators for converter and inverter. Simulation results demonstrate robust, precise, and fast dynamic behavior of system.DOI:http://dx.doi.org/10.11591/ijece.v3i3.347

Direct Power Control for AC/DC/ACConverters in Doubly Fed Induction Generators Based Wind Turbine

In this paper direct power control (DPC) strategy is applied to control a doubly fed induction generator (DFIG) based wind energy generation system. A three level NPC ac/dc/ac converter is controlled by direct power control method. The rotor side converter is controlled by a novelle switching table based a double active power hysteresis band method. The selects appropriates voltage vector based on the instantaneous errors between the reference and estimated values of active and reactive powers and rotor flux position. Also the grid side is controlled by direct power control based a grid voltage position to ensures a constant DC voltage, Simulation results on a demonstrate robust, precise, and fast dynamic behavior of system.DOI:http://dx.doi.org/10.11591/ijece.v2i3.284

Negotiating and delegating obligations

International audienceIn this paper, we describe a security model where users are allowed to control their obligations partially or totally, depending on the security policy. The main motivation of our work is to design more flexible systems that take into account users' requirements in order to avoid obligation violations and therefore sanctions. In our model, users are able to negotiate or delegate their obligations in the case of incapacity to fulfill them. This is an important aspect to be considered, since it is common that, at work or in everyday life, a user may need to negotiate the fulfillment of a given obligation, or also need the help of others to perform a task on his/her behalf. This may be due to several reasons such as absence, vacation, conflict of interest, lack of time, of resource, of competence or simply for the sake of efficiency. In our model, we propose an approach to deal with the negotiation and the delegation of obligations based on the concept of contexts

Misconfiguration Management of Network Security Components

Many companies and organizations use firewalls to control the access to their network infrastructure. Firewalls are network security components which provide means to filter traffic within corporate networks, as well as to police incoming and outcoming interaction with the Internet. For this purpose, it is necessary to configure firewalls with a set of filtering rules. Nevertheless, the existence of errors in a set of filtering rules is very likely to degrade the network security policy. The discovering and removal of these configuration errors is a serious and complex problem to solve. In this paper, we present a set of algorithms for such a management. Our approach is based on the analysis of relationships between the set of filtering rules. Then, a subsequent rewriting of rules will derive from an initial firewall setup -- potentially misconfigured -- to an equivalent one completely free of errors. At the same time, the algorithms will detect useless rules in the initial firewall configuration.Comment: 9 pages, 4 figures, 10 references, 7th International Symposium on System and Information Security (SSI), Sao Paulo, Brazi

Aggregating and Deploying Network Access Control Policies

The existence of errors or inconsistencies in the configuration of security components, such as filtering routers and/or firewalls, may lead to weak access control policies -- potentially easy to be evaded by unauthorized parties. We present in this paper a proposal to create, manage, and deploy consistent policies in those components in an efficient way. To do so, we combine two main approaches. The first approach is the use of an aggregation mechanism that yields consistent configurations or signals inconsistencies. Through this mechanism we can fold existing policies of a given system and create a consistent and global set of access control rules -- easy to maintain and manage by using a single syntax. The second approach is the use of a refinement mechanism that guarantees the proper deployment of such a global set of rules into the system, yet free of inconsistencies.Comment: 9 page

Agent-based self-management of MPLS DiffServ-TE domain

MPLS DiffServ-TE presents the solution awaited so much by the network service providers by allowing a differentiation of services and a traffic engineering based on a fast packet switching technology. However, the management of such a network is not a simple function and could not be done manually. In this paper, we propose a novel architecture based on the Multi-Agent Systems (MAS) capable of managing automatically MPLS DiffServ-TE domains. Based on the network states, our intelligent agents take the appropriate decisions. They, for example, reconfigure the network accordingly5th IFIP International Conference on Network Control & Engineering for QoS, Security and MobilityRed de Universidades con Carreras en Informática (RedUNCI

Access and privacy control enforcement in RFID middleware systems: Proposal and implementation on the Fosstrak platform

International audienceRadio Frequency IDentification (RFID) technology offers a new way of automating the identification and storing of information in RFID tags. The emerging opportunities for the use of RFID technology in human centric applications like monitoring and indoor guidance systems indicate how important this topic is in term of privacy. Holding privacy issues from the early stages of RFID data collection helps to master the data view before translating it into business events and storing it in databases. An RFID middleware is the entity that sits between tag readers and database applications. It is in charge of collecting, filtering and aggregating the requested events from heterogeneous RFID environments. Thus, the system, at this point, is likely to suffer from parameter manipulation and eavesdropping, raising privacy concerns. In this paper, we propose an access and privacy controller module that adds a security level to the RFID middleware standardized by the EPCglobal consortium. We provide a privacy policy-driven model using some enhanced contextual concepts of the extended Role Based Access Control model, namely the purpose, the accuracy and the consent principles. We also use the provisional context to model security rules whose activation depends on the history of previously performed actions. To show the feasibility of our privacy enforcement model, we first provide a proof-of-concept prototype integrated into the middleware of the Fosstrak platform, then evaluate the performance of the integrated module in terms of execution time

A service dependency modeling framework for policy-based response enforcement

International audienceThe use of dynamic access control policies for threat response adapts local response decisions to high level system constraints. However, security policies are often carefully tightened during system design-time, and the large number of service dependencies in a system architecture makes their dynamic adaptation di±cult. The enforcement of a single re- sponse rule requires performing multiple con¯guration changes on multi- ple services. This paper formally describes a Service Dependency Frame- work (SDF) in order to assist the response process in selecting the pol- icy enforcement points (PEPs) capable of applying a dynamic response rule. It automatically derives elementary access rules from the generic access control, either allowed or denied by the dynamic response pol- icy, so they can be locally managed by local PEPs. SDF introduces a requires/provides model of service dependencies. It models the service architecture in a modular way, and thus provides both extensibility and reusability of model components. SDF is de¯ned using the Architecture Analysis and Design Language, which provides formal concepts for mod- eling system architectures. This paper presents a systematic treatment of the dependency model which aims to apply policy rules while minimizing con¯guration changes and reducing resource consumption