网络协议并行实现系统

析网络协议并行实现的必要性，探讨端系统与互连设备并行协议系统的实现体系结构和开发途径，通过示例展示了协议并行化技术的应用前景。     

纯函数式I/O的操作语义

目前被人们广泛采用的处理函数式Ｉ／Ｏ的机制有三种，ＭｏｎａｄＤｉａｌｏｇｕｅ，ＣＰＳ，本文采用ＣＣＳ的理论和方法，把互模拟等价作为Ｉ／Ｏ程序的相等关系，描述了这三种Ｉ／Ｏ机制的操作语义，推导出这三种Ｉ／Ｏ机制相互之间的转换关系，从而证明了这三种Ｉ／Ｏ机制在语义上是等价的。     

项重写的图实现

图重写能够有效地实现项重写。文章从项重写的图实现的角度出发，研究了图重写模拟项重写的正确性和完备性：在无环出现的情况下，图重写对一切项重写下正确；在无环出现的条件下，图重写对左线性合流的项重写是完备的。     

Asymptotic properties of keys and functional dependencies in random databases

Practical database applications give the impression that sets of constraints are rather small and that large sets are unusual and are caused by bad design decisions. Theoretical investigations, however, show that minimal constraint sets are potentially very large. Their size can be estimated to be exponential in terms of the number of attributes. The gap between observation in practice and theory results in the rejection of theoretical results. However, practice is related to average cases and is not related to worst cases.

The theory used until now considered the worst-case complexity. This paper aims to develop a theory for the average-case complexity. Several probabilistic models and asymptotics of corresponding probabilities are investigated for random databases formed by independent random tuples with a common discrete distribution. Poisson approximations are studied for the distributions of some characteristics for such databases where the number of tuples is sufficiently large. We intend to prove that the exponential complexity of key sets and sets of functional dependencies is rather unusual and almost all minimal keys in a relation have a length which depends mainly on the size of the relation.     

接枝染色工艺——提高直接翠蓝GL的上染率

本技术用接枝剂 CS 在纤维素纤维上接枝改性,使直接翠蓝 GL 对纤维的直接性增加,使该染料的上染百分率提高,从而达到降低成本、减少三废、提高产品质量的目的。     

ZS整理剂对涤棉和涤粘中长织物的后加工

目前染整厂对含纤维素纤维的织物,一般采用氨基树脂加工。本文叙述了为减少加工车间的甲醛气体的弥漫,改用新型树脂后取得了超过原工艺的整理效果。     

Existence and multiplicity of positive periodic solutions for a class of higher-dimension functional differential equations with impulses

This paper deals with the existence of multiple periodic solutions for n-dimensional functional differential equations with impulses. By employing the Krasnoselskii fixed point theorem, we obtain some easily verifiable sufficient criteria which extend previous results.     

A compact fixpoint semantics for term rewriting systems

This work is motivated by the fact that a “compact” semantics for term rewriting systems, which is essential for the development of effective semantics-based program manipulation tools (e.g. automatic program analyzers and debuggers), does not exist. The big-step rewriting semantics that is most commonly considered in functional programming is the set of values/normal forms that the program is able to compute for any input expression. Such a big-step semantics is unnecessarily oversized, as it contains many “semantically useless” elements that can be retrieved from a smaller set of terms. Therefore, in this article, we present a compressed, goal-independent collecting fixpoint semantics that contains the smallest set of terms that are sufficient to describe, by semantic closure, all possible rewritings. We prove soundness and completeness under ascertained conditions. The compactness of the semantics makes it suitable for applications. Actually, our semantics can be finite whereas the big-step semantics is generally not, and even when both semantics are infinite, the fixpoint computation of our semantics produces fewer elements at each step. To support this claim we report several experiments performed with a prototypical implementation.     

Modular inference of subprogram contracts for safety checking

Contracts expressed by logic formulas allow one to formally specify expected behavior of programs. But writing such specifications manually takes a significant amount of work, in particular for uninteresting contracts which only aim at avoiding run-time errors during the execution. Thus, for programs of large size, it is desirable to at least partially infer such contracts. We propose a method to infer contracts expressed as boolean combinations of linear equalities and inequalities by combining different kinds of static analyses: abstract interpretation, weakest precondition computation and quantifier elimination. An important originality of our approach is to proceed modularly, considering subprograms independently.