Rodrigo Ferreira

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We study the relationship between Concurrent Separation Logic (CSL) and the assume-guarantee (A-G) method (a.k.a. rely-guarantee method). We show in three steps that CSL can be treated as a specialization of the A-G method for well-synchronized concurrent programs. First, we present an A-G based program logic for a low-level language with built-in locking(More)
In this paper, we formalize relaxed memory models by giving a parameterized operational semantics to a concurrent programming language. Behaviors of a program under a relaxed memory model are defined as behaviors of a set of related programs under the sequentially consistent model. This semantics is parameterized in the sense that different memory models(More)
The ENCOURAGE project aims at rationalizing energy usage in building by implementing a smart energy grid based on intelligent scheduling of energy consuming appliances, renewable energy production, and inter-building energy trading. This paper presents the reference architecture proposed in the context of the ENCOURAGE project, and relates it with the goals(More)
In this paper we propose a method to develop an omnidirectional kick (behavior) for a humanoid robot. This behavior uses a path planning module to create a trajectory that the foot must follow to propel the ball in the intended direction. Two additional modules were required when performing the movement: Inverse kinematics module which computes the value of(More)
Ocular toxoplasmosis can result in recurrent uveitis. Studies have shown that a correlation between active ocular toxoplasmosis and the presence of anti-Toxoplasma gondii secretory IgA (SIgA) in tears. This study compares anti-T. gondii SIgA levels in patients' tears during the acute and inactive phases of toxoplasmic uveitis. Twenty-nine positive tear(More)
Cloud computing datacenters provide thousands to millions of virtual machines (VMs) on-demand in highly dynamic environments, requiring quick placement of requested VMs into available physical machines (PMs). Due to the randomness of customer requests, the Virtual Machine Placement (VMP) should be formulated as an online optimization problem. This work(More)
Formal reasoning about concurrent programs is usually done with the assumption that the underlying memory model is sequentially consistent, i.e. the execution outcome is equivalent to an interleaving of instructions according to the program order. However, memory models in reality are weaker in order to accommodate compiler and hardware optimizations. To(More)
To any graph G one can associate a toric variety X(PG), obtained as a blowup of projective space along coordinate subspaces corresponding to connected subgraphs of G. The polytope of this toric variety is the graph associahedron of G, a class of polytopes that includes the permutohedron, associahedron, and stellahedron. We show that the space X(PG) is(More)
The aim of this paper is to show how the use of a fuzzy logic system associated to the amount estimation of items in stock can reduce the required amount of spare items of a purchase order, making it possible to determine with greater precision the minimum purchase lot for an order and so minimizing storage costs. Keeping lower the average stock levels(More)