A compiler for parsing schemata

We present a compiler that can be used to automatically obtain efficient Java implementations of parsing algorithms from formal specifications expressed as parsing schemata. The system performs an analysis of the inference rules in the input schemata in order to determine the best data structures and indexes to use, and to ensure that the generated implementations are efficient. The system described is general enough to be able to handle all kinds of schemata for different grammar formalisms, such as context‐free grammars and tree‐adjoining grammars, and it provides an extensibility mechanism allowing the user to define custom notational elements. This compiler has proven very useful for analyzing, prototyping and comparing natural‐language parsers in real domains, as can be seen in the empirical examples provided at the end of the paper. Copyright © 2008 John Wiley & Sons, Ltd.     

Quantum programming languages

After giving a bird’s view of some existing quantum programming languages, this paper reports the recent results made by the quantum computation group of the State Key Laboratory for Novel Software Technology and the Department of Computer Science and Technology at Nanjing University, i.e., the quantum programming languages NDQJava, NDQFP and their processing systems.     

容错的网络声明式程序

介绍了基于递归规则的网络声明式语言Netlog的语法和分布式不动点语义,定义了强良好的程序,并证明了强良好的程序的计算结果对有限的消息丢失不敏感.     

Stability, Growth, and Decline in Adult Life Span Development of Declarative Memory: Cross-Sectional and Longitudinal Data From a Population-Based Study.

Five-year changes in episodic and semantic memory were examined in a sample of 829 participants (35-80 years). A cohort-matched sample (N=967) was assessed to control for practice effects. For episodic memory, cross-sectional analyses indicated gradual age-related decrements, whereas the longitudinal data revealed no decrements before age 60, even when practice effects were adjusted for. Longitudinally, semantic memory showed minor increments until age 55, with smaller decrements in old age as compared with episodic memory. Cohort differences in educational attainment appear to account for the discrepancies between cross-sectional and longitudinal data. Collectively, the results show that age trajectories for episodic and semantic memory differ and underscore the need to control for cohort and retest effects in cross-sectional and longitudinal studies, respectively. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Declarative Formalization of Reasoning Strategies: A Case Study on Heuristic Nonlinear Planning

We study the declarative formalization of reasoning strategies by presenting declarative formalizations of: (1) the SNLP algorithm for nonlinear planning, and (2) a particular algorithm for blocks world nonlinear planning proposed in this paper. The formal models of a heuristic forward chaining planner, which can take advantage of declarative formalizations of action selection strategies, and of a reasoning strategy based planner, which can use declarative formalizations of reasoning strategies, are proposed. The effectiveness of these systems is studied from formal and empirical points of view. Empirical results showing how the use of declarative formalizations of reasoning strategies can reduce the amount of search required for solving planning problems (with respect to state of the art planning systems) are presented.     

On Logical Foundations of Multilevel Secure Databases

It is envisaged that the application of the multilevel security (MLS) scheme will enhance flexibility and effectiveness of authorization policies in shared enterprise databases and will replace cumbersome authorization enforcement practices through complicated view definitions on a per user basis. However, the critical problem with the current model is that the belief at a higher security level is cluttered with irrelevant or inconsistent data as no mechanism for attenuation is supported. Critics also argue that it is imperative for MLS database users to theorize about the belief of others, perhaps at different security levels, an apparatus that is currently missing and the absence of which is seriously felt.The impetus for our current research is the need to provide an adequate framework for belief reasoning in MLS databases. In this paper, we show that these concepts can be captured in a F-logic style declarative query language, called MultiLog, for MLS deductive databases for which a proof theoretic, model theoretic and fixpoint semantics exist. This development is significant from a database perspective as it now enables us to compute the semantics of MultiLog databases in a bottom-up fashion. We also define a bottom-up procedure to compute unique models of stratified MultiLog databases. Finally, we establish the equivalence of MultiLog's three logical characterizations—model theory, fixpoint theory and proof theory.     

真稳定类与辩论语义

稳定类语义和辨论语义是逻辑程序语义学研究方面突出的两种语义统一框架理论,它们统一了一些很重要的语义,因为它们有着不同的直觉和概念,它们的相互关系并不清楚。我们在它们最基础的概念层次上证明了,常规逻辑程序句法下二者是等价的,它们有着同样的语义统一能力。基于这个结果,我们为有前途的辨论语义指明一种迭代构造的方法。     

面向AI的数据管理技术综述

人工智能技术因其强大的学习和泛化能力已被广泛应用于各种真实场景中.然而,现有的人工智能技术仍然面临着三大挑战:第一,现有的AI技术使用门槛高,依赖于AI从业者选择合适模型、设计合理参数、编写程序,因此很难被广泛应用到非计算机领域;第二,现有的AI算法训练效率低,造成了大量计算资源的浪费,甚至延误决策时机;第三,现有的A...     

智能主体在构件检索中的知识处理研究

分布式构件库系统中,智能主体可通过协作联合完成用户的检索要求。对构件检索来说,确定哪些构件库拥有目标构件是一个需要首先解决的数据源选择问题。智能主体拥有自己的知识库,并且需要具备学习能力,能更新其知识库以保持检索结果的有效性。文章讨论了可更新的主体,它可以将新的信息合并到给定的知识库中。我们提出了一种基于逻辑程序设计的知识表达和更新方法,该方法遵从声明式更新策略以执行更新任务。我们所提出的可更新主体具有清晰的语义,也能够以恰当的方式处理不一致的信息,从而较智能地解决了数据源选择问题。     

三维陈述式约束模型的自动生成

由于缺乏有效的自动生成约束模型的方法，三维变量化技术的进一步发展受到制约，通过转换边界表示和提取特征中的本质约束信息，自动生成三维陈述式约束模型，以InteSolid2.0为基础，实现了原型系统。