Self-emergence of a common lexicon by evolution in teams of autonomous agents

In multi-agent systems, the study of language and communication is an active field of research. In this paper we present the application of evolutionary strategies to the self-emergence of a common lexicon in a population of agents. By modeling the vocabulary or lexicon of each agent as an association matrix or look-up table that maps the meanings (i.e. the objects encountered by the agents or the states of the environment itself) into symbols or signals we check whether it is possible for the population to converge in an autonomous, decentralized way to a common lexicon, so that the communication efficiency of the entire population is optimal. We have conducted several experiments aimed at testing whether it is possible to converge with evolutionary strategies to an optimal Saussurean communication system. We have organized our experiments alongside two main lines: first, we have investigated the effect of the population size on the convergence results. Second, and foremost, we have also investigated the effect of the lexicon size on the convergence results. To analyze the convergence of the population of agents we have defined the population's consensus when all the agents (i.e. 100% of the population) share the same association matrix or lexicon. As a general conclusion we have shown that evolutionary strategies are powerful enough optimizers to guarantee the convergence to lexicon consensus in a population of autonomous agents.     

Array automata and operations on array languages

Array automata acting on scenes (two dimensional tapes) are defined. The set of scenes accepted by array automata are proved to be equivalent to the set of arrays generated by array grammars. Certain operators like substitution, homomorphic replication and insertion are extended to sets of arrays. These operators yield interesting classes of pictures.     

Smooth Shape‐Aware Functions with Controlled Extrema

Functions that optimize Laplacian‐based energies have become popular in geometry processing, e.g. for shape deformation, smoothing, multiscale kernel construction and interpolation. Minimizers of Dirichlet energies, or solutions of Laplace equations, are harmonic functions that enjoy the maximum principle, ensuring no spurious local extrema in the interior of the solved domain occur. However, these functions are only C⁰ at the constrained points, which often causes smoothness problems. For this reason, many applications optimize higher‐order Laplacian energies such as biharmonic or triharmonic. Their minimizers exhibit increasing orders of continuity but lose the maximum principle and show oscillations. In this work, we identify characteristic artifacts caused by spurious local extrema, and provide a framework for minimizing quadratic energies on manifolds while constraining the solution to obey the maximum principle in the solved region. Our framework allows the user to specify locations and values of desired local maxima and minima, while preventing any other local extrema. We demonstrate our method on the smoothness energies corresponding to popular polyharmonic functions and show its usefulness for fast handle‐based shape deformation, controllable color diffusion, and topologically‐constrained data smoothing.     

浅析受贿罪讯问中的逻辑错误

犯罪嫌疑人的供述是认定受贿罪的“证据之王”,而讯问中逻辑错误的常见、多发,却严重削弱了其证明力,给反贪工作造成不必要的损失。为此,侦查人员在讯问中必须杜绝预期理由、混淆论题、不正当的复杂问语、推不出、论题含混等逻辑错误。     

A Monadic Semantics for Core Curry

We give a deterministic, big-step operational semantics for the essential core of the Curry language, including higher-order functions, call-by-need evaluation, non-determinism, narrowing, and residuation. The semantics is structured in modular monadic style, and is presented in the form of an executable interpreter written in Haskell. It uses monadic formulations of state, non-determinism, and resumption-based concurrency.     

Introducing QoS awareness in distributed programming: QTcl

A number of distributed applications require communication services with quality of service (QoS) guarantees. Building global‐scale distributed systems with predictable properties is one of the great challenges for computer systems engineering in the new century. Work undertaken within the Internet Engineering Task Force has led to the definition of novel architectural models for the Internet with QoS support. According to these models, the network has to be appropriately configured in order to provide applications with the required performance guarantees. In next‐generation networks, enabling applications to interact with the underlying QoS services is of primary importance. Hence, several special‐purpose application programming interfaces (APIs) have been defined to let applications negotiate QoS parameters across QoS‐capable networks. However, so far, none of these APIs are available in different operating environments. We believe that such features should be embedded in programming environments for distributed applications. In this work we present how we included QoS control features in Tcl, a programming language that has been widely adopted for the development of distributed multimedia applications. Our work has led to the implementation of QTcl, an extended Tcl interpreter that provides programmers with a new set of primitives, in full compliance with the standard SCRAPI programming interface for the RSVP protocol. QTcl in highly portable, in that it enables standard QoS negotiation to be performed in a seamless fashion on the most common operating systems. Copyright © 2003 John Wiley & Sons, Ltd.     

A residualizing semantics for the partial evaluation of functional logic programs

Recent proposals for multi-paradigm declarative programming combine the most important features of functional, logic and concurrent programming into a single framework. The operational semantics of these languages is usually based on a combination of narrowing and residuation. In this paper, we introduce a non-standard, residualizing semantics for multi-paradigm declarative programs and prove its equivalence with a standard operational semantics. Our residualizing semantics is particularly relevant within the area of program transformation where it is useful, e.g., to perform computations during partial evaluation. Thus, the proof of equivalence is a crucial result to demonstrate the correctness of (existing) partial evaluation schemes.