A Praxical Solution of the Symbol Grounding Problem

This article is the second step in our research into the Symbol Grounding Problem (SGP). In a previous work, we defined the main condition that must be satisfied by any strategy in order to provide a valid solution to the SGP, namely the zero semantic commitment condition (Z condition). We then showed that all the main strategies proposed so far fail to satisfy the Z condition, although they provide several important lessons to be followed by any new proposal. Here, we develop a new solution of the SGP. It is called praxical in order to stress the key role played by the interactions between the agents and their environment. It is based on a new theory of meaning—Action-based Semantics (AbS)—and on a new kind of artificial agents, called two-machine artificial agents (AM2). Thanks to their architecture, AM²s implement AbS, and this allows them to ground their symbols semantically and to develop some fairly advanced semantic abilities, including the development of semantically grounded communication and the elaboration of representations, while still respecting the Z condition.

Meaning in Artificial Agents: The Symbol Grounding Problem Revisited

The Chinese room argument has presented a persistent headache in the search for Artificial Intelligence. Since it first appeared in the literature, various interpretations have been made, attempting to understand the problems posed by this thought experiment. Throughout all this time, some researchers in the Artificial Intelligence community have seen Symbol Grounding as proposed by Harnad as a solution to the Chinese room argument. The main thesis in this paper is that although related, these two issues present different problems in the framework presented by Harnad himself. The work presented here attempts to shed some light on the relationship between John Searle’s intentionality notion and Harnad’s Symbol Grounding Problem.     

汉字在标识符号中的应用

汉字的创造始于朴素、单纯、生动、有趣的"物观取象"造字理念。汉字作为一种特殊形态比单纯的图形更富表现力。象形文字的图形化特征。使字意传达到图形成为可能,并具有极强的可塑性。将汉字及其笔画视为图形要素,多角度寻求形式美的现代要素。符号是思维的主体。"思维需要形状,而形状又必须从某种媒介中获取",符号化的汉字图形正是利用一定的媒介来代表或指示事物,成为可以互为转化的信息传播载体。     

Parallel Pattern-Based Systems for Computational Biology: A Case Study

Computational biology research is now faced with the burgeoning number of genome data. The rigorous postprocessing of this data requires an increased role for high-performance computing (HPC). Because the development of HPC applications for computational biology problems is much more complex than the corresponding sequential applications, existing traditional programming techniques have demonstrated their inadequacy. Many high level programming techniques, such as skeleton and pattern-based programming, have therefore been designed to provide users new ways to get HPC applications without much effort. However, most of them remain absent from the mainstream practice for computational biology. In this paper, we present a new parallel pattern-based system prototype for computational biology. The underlying programming techniques are based on generic programming, a programming technique suited for the generic representation of abstract concepts. This allows the system to be built in a generic way at application level and, thus, provides good extensibility and flexibility. We show how this system can be used to develop HPC applications for popular computational biology algorithms and lead to significant runtime savings on distributed memory architectures.     

一种基于双代理架构的嵌入式Internet计算模型

随着芯片技术的发展以及互联网的个性化、移动化趋势,嵌入式Internet系统逐渐成为研究的热点。文章根据嵌入式系统的特点,提出了基于浏览界代理／智能代理服务器(双代理)的嵌入式Internet计算模型。该模型通过采用静态、动态缓存管理、页面压缩、协议优化等方法避开了嵌入式系统的弱点。从试验数据看,该模型较为有效地减少了数据传输量,达到了节约有限带宽、提高响应时间的目的。     

Computational expressiveness of Genetic Systems

We introduce Genetic Systems, a formalism inspired by genetic regulatory networks and suitable for modeling the interactions between the genes and the proteins, acting as regulatory products.The generation of new objects, representing proteins, is driven by genetic gates: a new object is produced when all the activator objects are available in the system, and no inhibitor object is available. Activators are not consumed by the application of such an evolution rule. Objects disappear because of degradation: each object is equipped with a lifetime, and the object decays when such a lifetime expires.We investigate the computational expressiveness of Genetic Systems: we show that they are Turing equivalent by providing encodings of Random Access Machines in Genetic Systems.     

A Computational Method for Determining Strong Stabilizability of n-D Systems

This paper describes an algorithm for the following problem: given two multivariate complex or real polynomials f and g , decide whether there exist complex or real polynomials h and k such that both k and fh + gk have no zero in the unit polydisc. This problem, known as strong stabilizability, is fundamental in control theory, with important applications in designing stable feedback systems with a stable compensator. Our algorithm for solving the problem is formulated based on the cylindrical algebraic decomposition(cad) of an algebraic variety. While recent applications of cad to systems and control have been focused on those problems which have a quantifier elimination formulation, our method is novel in that it explicitly computes some topological properties of an algebraic variety based on the cad to solve the problem for which a quantifier elimination formulation is not readily available.     

高速系统的接地策略与电源抗干扰研究

在高速系统的设计与实现中,各种分布参数的影响,地线排布,电源去耦等实际问题最为突出,也是造成系统设计失败的重要原因,本文针对高速系统的接地策略与电源抗干扰问题阐述的一些基本的实现策略与技术。     

Scientific Theories of Computational Systems in Model Checking

Model checking, a prominent formal method used to predict and explain the behaviour of software and hardware systems, is examined on the basis of reflective work in the philosophy of science concerning the ontology of scientific theories and model-based reasoning. The empirical theories of computational systems that model checking techniques enable one to build are identified, in the light of the semantic conception of scientific theories, with families of models that are interconnected by simulation relations. And the mappings between these scientific theories and computational systems in their scope are analyzed in terms of suitable specializations of the notions of model of experiment and model of data. Furthermore, the extensively mechanized character of model-based reasoning in model checking is highlighted by a comparison with proof procedures adopted by other formal methods in computer science. Finally, potential epistemic benefits flowing from the application of model checking in other areas of scientific inquiry are emphasized in the context of computer simulation studies of biological information processing.     

Computational Logic in Multi-Agent Systems: Recent Advances and Future Directions

Starting from the early days of multi-agent systems research, considerable effort has been devoted to giving formal foundations to agent technologies. Work done in this direction, based on computational logic, is an attempt to bridge an existing gap, between theoretical frameworks and their practical implementations. In the last two editions of the workshop on Computational Logic in Multi-Agent Systems, CLIMA'01 and CLIMA'02, two discussion panels have been organized, aimed at bringing researchers together and exchanging ideas on a number of topics. In this article, we elaborate on the outcome of such panels, to draw some considerations about the recent advances and future directions of Computational Logic in Multi-Agent Systems.     

Brittle Software: A Programming Paradox

Software provides the means to both approximate reality in functional models and alter these models as reality or our perceptions of it change. Unfortunately, three of our software engineering concepts have limited software's representation and adaptability. Consequently, many of us who are using these concepts are developing not software but brittleware, systems that are rigid and difficult to modify.     

Evolutionary Adaptation of Nonlinear Dynamical Systems in Computational Neuroscience

We propose evolutionary analysis by synthesis as a powerful tool in computational neuroscience. We present applications of evolution strategies to the adaptation of dynamical systems for brain modeling. First, we compare evolutionary and gradient-based optimization of dynamic neural fields on an artificial benchmark problem. Then we adjust a few-neuron model developed for explaining our recent findings in a neurobiological experiment, in which we studied the processing of temporal sequences of stimuli in the cortex.     

A Survey of Artificial Cognitive Systems: Implications for the Autonomous Development of Mental Capabilities in Computational Agents

This survey presents an overview of the autonomous development of mental capabilities in computational agents. It does so based on a characterization of cognitive systems as systems which exhibit adaptive, anticipatory, and purposive goal-directed behavior. We present a broad survey of the various paradigms of cognition, addressing cognitivist (physical symbol systems) approaches, emergent systems approaches, encompassing connectionist, dynamical, and enactive systems, and also efforts to combine the two in hybrid systems. We then review several cognitive architectures drawn from these paradigms. In each of these areas, we highlight the implications and attendant problems of adopting a developmental approach, both from phylogenetic and ontogenetic points of view. We conclude with a summary of the key architectural features that systems capable of autonomous development of mental capabilities should exhibit     

Limited Computational Ability and Approximation of Dynamical Systems

This paper addresses problems due to approximation of dynamical systems. Theapproach presented here is based on the notion of the shadowing property ofa dynamical system and on the use of pseudotrajectories to approximate trueorbits. In particular, specific results in the case of attractors and thenotion of generalized shadowing are reviewed. The evidence described may berelevant for a wide range of economic models, whenever agents that havelimited computational ability, such as agents relying on digital computers,are concerned. The final section presents two sample applications to economicmodels.     

Computational Methods for Verification of Stochastic Hybrid Systems

Stochastic hybrid system (SHS) models can be used to analyze and design complex embedded systems that operate in the presence of uncertainty and variability. Verification of reachability properties for such systems is a critical problem. Developing sound computational methods for verification is challenging because of the interaction between the discrete and the continuous stochastic dynamics. In this paper, we propose a probabilistic method for verification of SHSs based on discrete approximations focusing on reachability and safety problems. We show that reachability and safety can be characterized as a viscosity solution of a system of coupled Hamilton-Jacobi-Bellman equations. We present a numerical algorithm for computing the solution based on discrete approximations that are derived using finite-difference methods. An advantage of the method is that the solution converges to the one for the original system as the discretization becomes finer. We also prove that the algorithm is polynomial in the number of states of the discrete approximation. Finally, we illustrate the approach with two benchmarks: a navigation and a room heater example, which have been proposed for hybrid system verification.     

射频识别系统的可靠性及计算模型

为全面、客观评价射频识别(radio frequency identification,RFID)系统可靠性性能,在分析RFID系统工作原理的基础上,给出基于标签识别率的RFID系统的可靠性定义和三种可靠性指标测度定义,分析了这三种可靠性指标测度间的关系;分析了影响RFID系统可靠性的关键因素,包括无线信道误码率对识别率的影响、标签碰撞对识别率的影响,由此提出了RFID系统可靠性计算的一般模型.仿真结果表明:提出的RFID系统可靠性计算的一般模型是合适、可行的,有利于RFID系统可靠性分析、设计和性能评估.