Several types of types in programming languages

Types are an important part of any modern programming language, but we often forget that the concept of type we understand nowadays is not the same it was perceived in the sixties. Moreover, we conflate the concept of "type" in programming languages with the concept of the same name in mathematical logic, an identification that is only the result of the convergence of two different paths, which started apart with different aims. The paper will present several remarks (some historical, some of more conceptual character) on the subject, as a basis for a further investigation. The thesis we will argue is that there are three different characters at play in programming languages, all of them now called types: the technical concept used in language design to guide implementation; the general abstraction mechanism used as a modelling tool; the classifying tool inherited from mathematical logic. We will suggest three possible dates ad quem for their presence in the programming language literature, suggesting that the emergence of the concept of type in computer science is relatively independent from the logical tradition, until the Curry-Howard isomorphism will make an explicit bridge between them.Comment: History and Philosophy of Computing, HAPOC 2015. To appear in LNC

A Comparative Content Analysis Of African American And Caucasian Role Portrayals In Broadcast Television Entertainment Programming

This study examines the nature and number of character portrayals in broadcast entertainment programming. More specifically, the portrayals of African American characters are examined and compared to Caucasian portrayals. The goal of this study is to determine what, if any, stereotypes may still be prevalent on broadcast television and if there are any discrepancies between portrayals of African American and Caucasian characters. A content analysis methodology was utilized to code 577 character occurrences from broadcast television entertainment programs popular with African Americans and Caucasian audiences. Each character occurrence was evaluated using thirty-two schematic differential items with regard to portrayal attributes, physical characteristics, behavioral characteristics, appearance characteristics, and the five factor model of personality elements. T-test and z-score analysis were used to determine significant differences between items. Results determined that African American characters were not portrayed in a negative manner when compared to Caucasian characters. African American characters were underrepresented on television but were within 2% of their population rate. However, in programming watched by African Americans, they were overrepresented. The most common significantly different characteristics found between African American and Caucasian characters on broadcast entertainment programming were hair color, skin color, amount of makeup and amount of accessories

The regional model for Mediterranean agriculture

AgriPoliS is a multi-agent mixed integer linear programming (MIP) model, spatially explicit, developed in C++ language and suitable for long-term sim- ulations of agricultural policies. Beyond the mixed integer programming core, the model main feature is the interaction among a set of heterogeneous farm- ers and between them and the environment in which they operate. In this paper we describe an extension of the model allowing AgriPoliS to deal with typical characters of the Mediterranean agriculture. In particular AgriPoliS was extended to allow a generic number of products and soil types, included perennial crops and products with quality differentiation. Furthermore, it can explicitly take into account irrigation.Mediterranean Agriculture; Common Agricultural Policy; Agent-based Models

On Computing the Maximum Parsimony Score of a Phylogenetic Network

Phylogenetic networks are used to display the relationship of different species whose evolution is not treelike, which is the case, for instance, in the presence of hybridization events or horizontal gene transfers. Tree inference methods such as Maximum Parsimony need to be modified in order to be applicable to networks. In this paper, we discuss two different definitions of Maximum Parsimony on networks, "hardwired" and "softwired", and examine the complexity of computing them given a network topology and a character. By exploiting a link with the problem Multicut, we show that computing the hardwired parsimony score for 2-state characters is polynomial-time solvable, while for characters with more states this problem becomes NP-hard but is still approximable and fixed parameter tractable in the parsimony score. On the other hand we show that, for the softwired definition, obtaining even weak approximation guarantees is already difficult for binary characters and restricted network topologies, and fixed-parameter tractable algorithms in the parsimony score are unlikely. On the positive side we show that computing the softwired parsimony score is fixed-parameter tractable in the level of the network, a natural parameter describing how tangled reticulate activity is in the network. Finally, we show that both the hardwired and softwired parsimony score can be computed efficiently using Integer Linear Programming. The software has been made freely available

Graph kernels between point clouds

Point clouds are sets of points in two or three dimensions. Most kernel methods for learning on sets of points have not yet dealt with the specific geometrical invariances and practical constraints associated with point clouds in computer vision and graphics. In this paper, we present extensions of graph kernels for point clouds, which allow to use kernel methods for such ob jects as shapes, line drawings, or any three-dimensional point clouds. In order to design rich and numerically efficient kernels with as few free parameters as possible, we use kernels between covariance matrices and their factorizations on graphical models. We derive polynomial time dynamic programming recursions and present applications to recognition of handwritten digits and Chinese characters from few training examples

Educational Games for Learning Programming Languages

A concept of educational game for learning programming languages is presented. The idea of learning programming languages and improving programming skills through programming game characters’ behavior is described. The learning course description rules for using in games are suggested. The concept is implemented in a game for learning C# programming language. A common game architecture is modified for using in the educational game. The game engine is built on the base of the graphical engine Ogre3D and extended with game logic. The game has been developed as an industry level commercial product and is planned for sale to educational institutions

A path following algorithm for the graph matching problem

We propose a convex-concave programming approach for the labeled weighted graph matching problem. The convex-concave programming formulation is obtained by rewriting the weighted graph matching problem as a least-square problem on the set of permutation matrices and relaxing it to two different optimization problems: a quadratic convex and a quadratic concave optimization problem on the set of doubly stochastic matrices. The concave relaxation has the same global minimum as the initial graph matching problem, but the search for its global minimum is also a hard combinatorial problem. We therefore construct an approximation of the concave problem solution by following a solution path of a convex-concave problem obtained by linear interpolation of the convex and concave formulations, starting from the convex relaxation. This method allows to easily integrate the information on graph label similarities into the optimization problem, and therefore to perform labeled weighted graph matching. The algorithm is compared with some of the best performing graph matching methods on four datasets: simulated graphs, QAPLib, retina vessel images and handwritten chinese characters. In all cases, the results are competitive with the state-of-the-art.Comment: 23 pages, 13 figures,typo correction, new results in sections 4,5,