Timed CCP compositionally embeds Argos and Lustre

We prove that both the synchronous data-flow language Lustre restricted to types with finite values and the synchronous state-oriented language Argos are embedded in the synchronous paradigm Timed Concurrent Constraint Programming (tccp). In fact, for each of the two languages we provide a tccp language encoding it compositionally with respect to the syntax of programs and linearly with respect to the size of programs. Besides giving results of expressiveness for tccp, our encodings permit us to obtain a language tailored for programming reactive systems where both control handling aspects and data processing aspects are relevant.Author partially supported by MIUR progetto cofinanziato Modelli Formali per la Sicurezza e il Tempo and by ESPRIT Working Group Constraint Programming for Time Critical Applications, Project Number 23677Accepted in revised form 22 October 2003 by M. Broy, G. Lüttgen and M. Mendler     

Datalog extension for nested relations

The nested relational model allows relations that are not in first normal form. This paper gives an extension of Datalog rules for nested relations. In our approach, nested Datalog is a natural extension of Datalog introduced for the relational data model. A nested Datalog program has a hierarchical structure of rules and subprograms to manipulate relation values of nested relations. We introduce a new category of predicate symbols, the variable predicate symbols to refer to tuples of subrelations. The notion of soundness, safety and consistency is defined to avoid undesirable nested Datalog programs. The evaluation of nested Datalog is given in terms of the nested relational algebra. Finally, we relate the expressive power of nonrecursive nested Datalog to the power of nested relational algebra and safe nested tuple relational calculus.     

建筑师手记：创意中央的材料表意 方度国际建筑师事务所合伙人徐驰专访

文章记录了建筑师徐驰在南京＂创意中央项目＂的实践,通过对不同材料基本属性、构造方式、建造手段、表情达意方面的多种尝试,反映其在长期执业实践中,对材料表意的不断思考。     

PaL diagrams: A linear diagram-based visual language

Linear diagrams have recently been shown to be more effective than Euler diagrams when used for set-based reasoning. However, unlike the growing corpus of knowledge about formal aspects of Euler and Venn diagrams, there has been no formalisation of linear diagrams. To fill this knowledge gap, we present and formalise Point and Line (PaL) diagrams, an extension of simple linear diagrams containing points, thus providing a formal foundation for an effective visual language. We prove that PaL diagrams are exactly as expressive as monadic first-order logic with equality, gaining, as a corollary, an equivalence with the Euler diagram extension called spider diagrams. The method of proof provides translations between PaL diagrams and sentences of monadic first-order logic.     

On the expressiveness of second-order spider diagrams

Existing diagrammatic notations based on Euler diagrams are mostly limited in expressiveness to monadic first-order logic with an order predicate. The most expressive monadic diagrammatic notation is known as spider diagrams of order. A primary contribution of this paper is to develop and formalise a second-order diagrammatic logic, called second-order spider diagrams, extending spider diagrams of order. A motivation for this lies in the limited expressiveness of first-order logics. They are incapable of defining a variety of common properties, like ‘is even’, which are second-order definable. We show that second-order spider diagrams are at least as expressive as monadic second-order logic. This result is proved by giving a method for constructing a second-order spider diagram for any regular expression. Since monadic second-order logic sentences and regular expressions are equivalent in expressive power, this shows second-order spider diagrams can express any sentence of monadic second-order logic.     

On the expressive power of KLAIM-based calculi

We study the expressive power of variants of KLAIM, an experimental language with programming primitives for network-aware programming that combines the process algebra approach with the coordination-oriented one. KLAIM has proved to be suitable for programming a wide range of distributed applications with agents and code mobility, and has been implemented on the top of a runtime system written in Java. In this paper, the expressivity of its constructs is tested by distilling from it a few, more and more foundational, languages and by studying the encoding of each of them into a simpler one. The expressive power of the considered calculi is finally tested by comparing one of them with asynchronous π$\pi$-calculus.     

“信、达、雅”翻译原则在文学翻译中的应用

翻译过程中译者应遵循翻译原则,尽管翻译原则的研究极其重要,这种标准却是很难界定的,对于翻译标准的讨论也层出不穷,通过对国内外翻译标准的梳理并研究,借助文学翻译作为载体和研究对象,重点研究“信、达、雅”翻译原则在文学翻译中的应用和指导意义,避免局限于理论的翻译原则,增强翻译研究的实践意义。     

漆画语言中的抽象表现

漆画在今天作为一种纯粹的艺术形式，被越来越多的人所熟知和喜爱。萁独特的语言形式和审美取向有着无限的可能性与创造力。它特殊的质料语言形成了多种类型的抽象造型元素，这些抽象造型元素造就了漆画中别具一格的形式语言。而漆画语言的这种特点。也正是抽象形式在漆画创作中别具表现力的原因。于自身材料的特性自然绝妙的去发生适于滚画表现的图式特征使得漆画语言具有了无可比拟的抽象表现力。     

Comparing disjunctive modal transition systems with an one-selecting variant

An expressive class of abstractions for labeled transition systems is that of disjunctive modal transition systems (DMTS), featuring may- and must transitions as well as disjunctive hypertransitions (OR). In order to describe exclusive choice adequately, we develop a variant of DMTSs called 1-selecting modal transition systems (OMTS) that, roughly speaking, interprets hypertransitions exclusively (XOR). These abstract models, DMTSs and OMTSs, are compared with respect to their expressive power. By giving transformations or showing their non-existence, we show that the two setting can express the same sets of labeled transition systems, but 1-selecting modal transition systems have a richer refinement preorder.     

On the expressibility of priority

This short note offers results confirming that the priority operator of Baeten, Bergstra and Klop cannot be expressed using positive rule formats for operational semantics. Although expected, this inexpressibility result does not seem to have appeared before in the literature.