Encontrados 58 documentos, a visualizar página 1 de 6
Extending RBAC model to control sequences of CRUD expressions
Pereira, Óscar Mortágua; Regateiro, Diogo Domingues; Aguiar, Rui L.In database applications, access control is aimed at requests are mainly formalized by Create, Read, Update and Delete (CRUD)expressions. The supervision process can be formalized at a high level, such as based on the RBAC model, but in the end the relevant aspect is the data being accessed through each CRUD expression. In critical database applications access control can be enforced not on a CRUD by CRUD bas...
Scalable semantic aware context storage
Antunes, Mário; Gomes, Diogo; Aguiar, RuiIn recent years the Internet has grown by incorporating billions of small devices, collecting real-world information and distributing it though various systems. As the number of such devices grows, it becomes increasingly difficult to manage all these new information sources. Several context representation schemes have tried to standardize this information, however none of them have been widely adopted. Instead...
A concurrent tuple set architecture for call level interfaces
Mortágua, Óscar; Aguiar, Rui; Santos, Maribel YasminaCall Level Interfaces (CLI) are low level API aimed at providing services to connect two main components in database applications: client applications and relational databases. Among their functionalities, the ability to manage data retrieved from databases is emphasized. The retrieved data is kept in local memory structures that may be permanently connected to the host database. Client applications, beyond the...
A Concurrent Tuple Set Architecture for Call Level Interfaces
Pereira, Óscar M.; Aguiar, Rui L.; Santos, Maribel YasminaCall Level Interfaces (CLI) are low level API aimed at providing services to connect two main components in database applications: client applications and relational databases. Among their functionalities, the ability to manage data retrieved from databases is emphasized. The retrieved data is kept in local memory structures that may be permanently connected to the host database. Client applications, beyond the...
Reusable Business Tier Architecture driven by a wide typed service
Pereira, Óscar M.; Aguiar, Rui L.; Santos, Maribel YasminaCall Level Interfaces (CLI) are difficult to use mainly in intensive database applications with many Create, Read, Update and Delete (CRUD) expressions. As low level API, they are not suited to promote the development process of business tiers as reusable components, leading to the need of writing additional source code whenever a new CRUD expression is needed. To tackle this gap, this paper proposes an archite...
Runtime values driven by access control policies : statically enforced at the l...
Pereira, Óscar M.; Aguiar, Rui L.; Santos, Maribel YasminaAccess control is a key challenge in software engineering, especially in relational database applications. Current access control techniques are based on additional security layers designed by security experts. These additional security layers do not take into account the necessary business logic leading to a separation between business tiers and access control mechanisms. Moreover, business tiers are built fro...
Runtime values driven by access control policies: statically enforced at the le...
Pereira, Óscar Mortágua; Aguiar, Rui L.; Santos, Maribel YasminaAccess control is a key challenge in software engineering, especially in relational database applications. Current access control techniques are based on additional security layers designed by security experts. These additional security layers do not take into account the necessary business logic leading to a separation between business tiers and access control mechanisms. Moreover, business tiers are built fro...
A Cross-System Approach for Multimedia Services with IP Multicast in 4G Networks
Gomes, Diogo; Aguiar, Rui L.; Sargento, SusanaThe increased demand for multimedia services by mobile end users in recent years have driven both Broadcast and Wireless Network operators to develop new systems and architectures for the deployment of such services. The proposed solutions are nonetheless limited either in terms of QoS or Capabilities to deliver new interactive services. This paper highlights strengths and drawbacks of the existing technologies...
A sectored receiver for infrared wireless networks
Alves, L. N.; Aguiar, Rui L.; Vasconcelos, Eduardo de; Cura, Jose LuisThis paper presents an experimental sectored receiver for infrared wireless networks. The receiver comprises two sectors, each with a switched gain front-end and a signal-to-noise ratio estimator. These are then interconnected with a best-sector selector unit, able to compensate the gain switching characteristics of the front-ends. The circuit has been designed in a 0.8 μm CMOS technology.
Asynchronous design pattern for many-core and cloud operating systems
Santos, Bruno; Barraca, João Paulo; Aguiar, Rui L.One of the key aspects for many-core and cloud operating systems is message passing communication. The networking aspect of this mechanism requires a high degree of concurrency to handle communicating with thousands of cores simultaneously in an efficient and scalable manner. Non-blocking interfaces allows us to efficiently use a core and gives us concurrency without multiple threads, this also minimizes contex...
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