DSpace Coleção:https://rd.uffs.edu.br/handle/prefix/25182024-03-29T14:17:15Z2024-03-29T14:17:15ZSecure admission and execution of applications in noc-based many-cores systemsCaimi, Luciano Loreshttps://rd.uffs.edu.br/handle/prefix/32462019-11-06T17:18:06Z2019-01-01T00:00:00ZTítulo: Secure admission and execution of applications in noc-based many-cores systems
Autor(es): Caimi, Luciano Lores
Primeiro Orientador: Moraes, Fernando Gehm
Abstract/Resumen: The adoption of many-cores systems introduces the concern for data protection as a critical design requirement due to the resource sharing and the simultaneous executions of several applications on the platform. A secure application that processes sensitive data may have its security harmed by a malicious process. The literature contains several proposals to protect many-cores against attacks, focusing for example in the protection of the application execution or the access to shared memories. However, a solution covering the application lifetime, including its admission, execution and peripheral access, is a gap to be fulfilled. This Thesis discusses three security-related issues: the secure admission of applications, the prevention of resource sharing during their execution, and the safe access to external devices. This Thesis proposes a set of protocols and mechanisms, executed at runtime, to tackle these issues. The application admission authenticates trusty entities. An entity authenticated might deploy applications, requiring only a Message Authentication Code (MAC) verification to guarantee the application integrity. Secure applications are mapped into Opaque Secure Zones (OSZ), with the reservation of all Processing Elements (PEs)andcommunicationresources. AlltrafficflowsthatshouldcrosstheOSZ arererouted to the outside of the OSZ. Such isolation approach avoids Denial-of-Service (DoS), timing, and spoofing attacks and guarantees data confidentiality and integrity. External devices are also authenticated, enabling the use of a dedicated shared key to encrypt the peripheral exchange messages. Concerning the application admission, the dominant overhead corresponds to the MAC computation and verification steps, that results in the latency to start a secure application by a few milliseconds. Concerning the application execution, the evaluation shows a insignificant impact on the execution time of secure and non-secure applications, even in the presence of several broken paths and the respective rerouting and retransmission of messages. Protection of message header and payload during the peripheral access correspond to the main overhead in the communication latency. The concern is the trade-off between the cryptography cost (hardware or software) versus the additional latency in the communication. This Thesis advances the state-of-the-art on the NoC-based many-core systems research area since that encompasses security mechanism to entire application lifetime. The lightweight mechanism to mutual authentication between external entities and the many-core, and a Message Authentication Code to protect the application’
source code are innovations proposed in the Thesis. The protection of application execution without cryptographic mechanisms through the OSZ, avoiding both communication and computational resources sharing represent another contribution of this Thesis.
Instituição: Pontifícia Universidade Católica do Rio Grande do Sul
Tipo: Tese2019-01-01T00:00:00ZNovel procedures for graph edge-colouringZatesko, Leandro Mirandahttps://rd.uffs.edu.br/handle/prefix/25502019-03-11T11:35:57Z2018-01-01T00:00:00ZTítulo: Novel procedures for graph edge-colouring
Autor(es): Zatesko, Leandro Miranda
Primeiro Orientador: Carmo, Renato
Abstract/Resumen: The chromatic index of a graph G is the minimum number of colours needed to colour the edges of G in a manner that no two adjacent edges receive the same colour. By the celebrated Vizing’s Theorem, the chromatic index of any simple graph G is either its maximum degree ∆ or it is ∆+1, in which case G is said to be Class 1 or Class 2, respectively. Computing an optimal edge-colouring of a graph or simply determining its chromatic index are importantNP-hard problems which appear in noteworthy applications, like sensor networks, optical networks, production control, and games. In this work we present novel polynomial-time procedures for optimally edge-colouring graphs belonging to some large sets of graphs. For example, let X be the class of the graphs whose majors (vertices of degree ∆) have local degree sum at most ∆2−∆ (by ‘local degree sum’ of a vertex x we mean the sum of the degrees of the neighbours of x). We show that almost every graph is in X and, by extending the recolouring procedure used by Vizing’s in the proof for his theorem, we show that every graph in X is Class 1. We further achieve results in other graph classes, such as join graphs, circular-arc graphs, and complementary prisms. For instance, we show that a complementary prism can be Class 2 only if it is a regular graph distinct from the K2. Concerning join graphs, we show that if G1 and G2 are disjoint graphs such that |V(G1)|6|V(G2)|and ∆(G1) > ∆(G2), and if the majors of G1 induce an acyclic graph, thenthejoingraphG1∗G2 isClass1. Besidestheseresultsonedge-colouring,we present partial results on total colouring joingraphs,cobipartitegraphs,andcircular-arcgraphs, as well as a discussion on a recolouring procedure for total colouring.
Instituição: Universidade Federal do Paraná
Tipo: Tese2018-01-01T00:00:00ZAnálise de qualidade de Steering Behaviors e desempenho da Unity 5Spiller, Kevin Mitchellhttps://rd.uffs.edu.br/handle/prefix/20012021-01-22T12:55:32Z2018-01-01T00:00:00ZTítulo: Análise de qualidade de Steering Behaviors e desempenho da Unity 5
Autor(es): Spiller, Kevin Mitchell
Primeiro Orientador: Wuerges, Emílio
Abstract/Resumen: Artificial intelligence is a fascinating field and filled with practicable areas, one of these
areas is the area of digital games. In this area it is possible to find several techniques of artificial
intelligence, being one of them the steering behaviors, directional behaviors that aims to
help autonomous characters to move in a more realistic way, using simple techniques involving
vectors. In this paper we discuss three different steering behavior techniques that have been implemented
and modified in the Unity 5 game engine, such as Arrival, Collision Avoidance and
Wall Avoidance. This work aims to analyze the quality of these steering behaviors as well as
analyze the performance of this game engine. To achieve these objectives a number of quality
and performance metrics were collected and analyzed after simulations were performed in nine
scenarios adapted from a benchmark for Unity 5 that can represent real world scenarios. At
the end of the work it was possible to verify notable differences in quality metrics due to the
different scenarios, number of agents and behaviors, as well as to verify that the frame rate per
second is more sensitive to the number of agents and their behaviors while it was only partially
possible to prove that the total memory usage of the system is sensitive regarding the number
of game objects (agents, obstacles, etc.), number of agents and their behaviors.
Instituição: Universidade Federal da Fronteira Sul
Tipo: Monografia2018-01-01T00:00:00Z