Open set segmentation is a relatively new and unexplored task, with just a handful of methods proposed to model such tasks. We propose a novel method called CoReSeg that tackles the issue using class conditioned reconstruction of the input images according to their pixelwise mask. Our method conditions each input pixel to all known classes, expecting higher errors for pixels of unknown classes. It was observed that the proposed method produces better semantic consistency in its predictions than the baselines, resulting in cleaner segmentation maps that better fit object boundaries. CoReSeg outperforms state-of-the-art methods on the Vaihingen and Potsdam ISPRS datasets, while also being competitive on the Houston 2018 IEEE GRSS Data Fusion dataset. Our official implementation for CoReSeg is available at: https://github.com/iannunes/CoReSeg.

Petrobras is Brazil's largest publicly-held company, operating in the oil, natural gas, and energy industry. Internal efforts enabled Petrobras to identify Digital Transformation (DT) opportunities to further promote their operational excellence. While addressing these opportunities typically requires Research and Development (R&D) uncertainties that could lead traditional R&D cooperation terms to be negotiated in years, there are time-to-market constraints for fast-paced deliveries to experiment solution options. Having this in mind, they partnered up with PUC-Rio to establish a new DT initiative. [Goal] The goal of this paper is to present the Lean R&D approach, tailored within the new initiative to meet the aforementioned DT needs. [Method] We designed Lean R&D integrating the following building blocks: (i) Lean Inceptions, to allow stakeholders to jointly outline a Minimal Viable Product (MVP); (ii) parallel technical feasibility assessment and conception phases, allowing to `fail fast'; (iii) scrum-based development management; and (iv) strategically aligned continuous experimentation to test business hypotheses. We report on first experiences of applying Lean R&D in practice. [Results] Lean R&D enabled addressing research-related uncertainties early and to efficiently deliver valuable MVPs within fast-paced four months cycles. [Conclusions] In our first experiences Lean R&D showed itself suitable for supporting DT initiatives. However, more formal case studies are needed. The business strategy alignment and the continuous support of a highly qualified research team were considered key success factors.

Phase unwrapping is the process of recovering a continuous phase signal from an original signal wrapped in the ([Formula: see text]] interval. It is a critical step of coherent signal processing, with applications such as synthetic aperture radar, acoustic imaging, magnetic resonance, X-ray crystallography, and seismic processing. In the field of computational optics, this problem is classically treated as a norm-minimization problem, in which one seeks to minimize the differences between the gradients of the original wrapped signal and those of the continuous unwrapped signal. When the [Formula: see text]–norm is considered, the number of differences should be minimized, leading to a difficult combinatorial optimization problem. We propose an approximate model for the [Formula: see text]–norm phase unwrapping problem in two dimensions (2D), in which the singularities of the wrapped phase image are associated with a graph where the vertices have −1 or [Formula: see text] polarities. The objective is to find a minimum-cost balanced spanning forest where the sum of the polarities is equal to zero in each tree. We introduce a set of primal and dual heuristics, a branch-and-cut algorithm, and a hybrid metaheuristic to efficiently find exact or heuristic solutions. These approaches move us one step closer to optimal solutions for 2D [Formula: see text]–norm phase unwrapping; such solutions were previously viewed, in the signal processing literature, as highly desirable but not achievable.

The Team Orienteering Problem is a routing problem on a graph with durations associated to the arcs and profits assigned to visiting the vertices. A fixed number of identical vehicles, with a limited total duration for their routes, is given. The total profit gathered by all routes is to be maximized. We devise an extended formulation where edges are indexed by the time they are placed in the route. A new class of inequalities, min cut, and the triangle clique cuts of Pessoa et. al., 2007 are added. The resulting formulation is solved by column generation. Branching is done following the work of Boussier et al. 2007, to which the branch-cut-and-price algorithm here proposed is compared. A few new upper bounds were obtained. Overall the presented approach has shown to be very competitive.

Abstract This article presents a robust branch‐cut‐and‐price algorithm for the heterogeneous fleet vehicle routing problem (HFVRP), vehicles may have distinct capacities and costs. The columns in the formulation are associated to q‐routes, a relaxation of capacitated elementary routes that makes the pricing problem solvable in pseudopolynomial time. Powerful new families of cuts are also proposed, which are expressed over a very large set of variables. Those cuts do not increase the complexity of the pricing subproblem. Experiments are reported where instances with up to 75 vertices were solved to optimality, a major improvement with respect to previous algorithms. © 2009 Wiley Periodicals, Inc. NETWORKS, 2009

This paper presents a search architecture that combines classical search techniques with spread activation techniques applied to a semantic model of a given domain. Given an ontology, weights are assigned to links based on certain properties of the ontology, so that they measure the strength of the relation. Spread activation techniques are used to find related concepts in the ontology given an initial set of concepts and corresponding initial activation values. These initial values are obtained from the results of classical search applied to the data associated with the concepts in the ontology. Two test cases were implemented, with very positive results. It was also observed that the proposed hybrid spread activation, combining the symbolic and the sub-symbolic approaches, achieved better results when compared to each of the approaches alone.

Abstract VLSI layout applications yield instances of the Steiner tree problem over grid graphs with holes, which are considered hard to be solved by current methods. In particular, preprocessing techniques developed for Steiner problems over general graphs are not likely to reduce, significantly, such VLSI instances. We propose a new preprocessing procedure, extending earlier ideas from the literature and improving their application, so as to make them effective for VLSI problems. We report significant reductions within reasonable computational times, obtained with the application of this procedure to 116 instances of the SteinLib. These reductions allowed a branch and cut to solve 28 of 32 open instances of the SteinLib, some with more than 10,000 vertices and 20,000 edges. © 2002 Wiley Periodicals, Inc.

Nilsson recently introduced a rigorous semantic generalization of logic in which the truth values of sentences are probability values. This led to state precisely several basic problems of artificial intelligence, a paradigm of which is probabilistic satisfiability (PSAT): determine, given a set of clauses and probabilities that these clauses are true, whether these probabilities are consistent. We consider several extensions of this model involving intervals on probability values, conditional probabilities and minimal modifications of probability values to ensure satisfiability. Investigating further an approach of G. Georgakopoulos, D. Kavvadias and C. H. Papadimitriou, we propose a column generation algorithm which allows to solve exactly all these extensions. Computational experience shows that large problems, with up to 140 variables and 300 clauses, may be solved in reasonable time. INFORMS Journal on Computing, ISSN 1091-9856, was published as ORSA Journal on Computing from 1989 to 1995 under ISSN 0899-1499.