SLT-Resolution for the Well-Founded Semantics

Global SLS-resolution and SLG-resolution are two representative mechanisms for top-down evaluation of the well-founded semantics of general logic programs. Global SLS-resolution is linear for query evaluation but suffers from infinite loops and redundant computations. In contrast, SLG-resolution resolves infinite loops and redundant computations by means of tabling, but it is not linear. The principal disadvantage of a non-linear approach is that it cannot be implemented using a simple, efficient stack-based memory structure nor can it be easily extended to handle some strictly sequential operators such as cuts in Prolog. In this paper, we present a linear tabling method, called SLT-resolution, for top-down evaluation of the well-founded semantics. SLT-resolution is a substantial extension of SLDNF-resolution with tabling. Its main features include: (1) It resolves infinite loops and redundant computations while preserving the linearity. (2) It is terminating, and sound and complete w.r.t. the well-founded semantics for programs with the bounded-term-size property with non-floundering queries. Its time complexity is comparable with SLG-resolution and polynomial for function-free logic programs. (3) Because of its linearity for query evaluation, SLT-resolution bridges the gap between the well-founded semantics and standard Prolog implementation techniques. It can be implemented by an extension to any existing Prolog abstract machines such as WAM or ATOAM.Comment: Slight modificatio

Linear Tabulated Resolution Based on Prolog Control Strategy

Infinite loops and redundant computations are long recognized open problems in Prolog. Two ways have been explored to resolve these problems: loop checking and tabling. Loop checking can cut infinite loops, but it cannot be both sound and complete even for function-free logic programs. Tabling seems to be an effective way to resolve infinite loops and redundant computations. However, existing tabulated resolutions, such as OLDT-resolution, SLG- resolution, and Tabulated SLS-resolution, are non-linear because they rely on the solution-lookup mode in formulating tabling. The principal disadvantage of non-linear resolutions is that they cannot be implemented using a simple stack-based memory structure like that in Prolog. Moreover, some strictly sequential operators such as cuts may not be handled as easily as in Prolog. In this paper, we propose a hybrid method to resolve infinite loops and redundant computations. We combine the ideas of loop checking and tabling to establish a linear tabulated resolution called TP-resolution. TP-resolution has two distinctive features: (1) It makes linear tabulated derivations in the same way as Prolog except that infinite loops are broken and redundant computations are reduced. It handles cuts as effectively as Prolog. (2) It is sound and complete for positive logic programs with the bounded-term-size property. The underlying algorithm can be implemented by an extension to any existing Prolog abstract machines such as WAM or ATOAM.Comment: To appear as the first accepted paper in Theory and Practice of Logic Programming (http://www.cwi.nl/projects/alp/TPLP

浅谈基层医院电子病历系统实施过程中存在的问题及对策

The paper, which took Yanggu People’s hospital’s EPR system in the information construction as a case，analyzed domestic EPR system’s current situation， summarized the problems of the EPR system in its implementation process, and some changes to our hospitals it brought.本文以阳谷县人民医院信息化建设中电子病历系统的实施为例，比较和分析国内医院电子病历实施现状，总结了电子病历系统在实施过程中所发生的问题，以及给我院带来的一些变化

Ray solvable linear systems and ray S2NS matrices

AbstractRay solvable linear systems and ray S2NS matrices are complex generalizations of the sign solvable linear systems and S2NS matrices. We use the determinantal ray unique matrices (instead of ray nonsingular matrices) as a generalization of SNS matrices, to generalize some fundamental results of S2NS matrices from the real case to complex case, such as the graph theoretical characterization, the inverse ray patterns and the upper bound of the number of nonzero entries of S2NS matrices. The well known characterization of the sign solvable linear systems (in terms of the L-matrices and S∗ matrices) is also generalized to ray solvable linear systems, and the relationships between the ray S∗-matrices and real S∗-matrices are investigated. Some examples are also given to illustrate that some results, such as the characterization of the sign inconsistent linear systems, do not carry over to the complex case

Time-optimal variational control of bright matter-wave soliton

Motivated by recent experiments, we present the time-optimal variational control of bright matter-wave soliton trapped in a quasi-one-dimensional harmonic trap by manipulating the atomic attraction through Feshbach resonances. More specially, we first apply a time-dependent variational method to derive the motion equation for capturing the soliton's shape, and secondly combine inverse engineering with optimal control theory to design the atomic interaction for implementing time-optimal decompression. Since the time-optimal solution is of bang-bang type, the smooth regularization is further adopted to smooth the on-off controller out, thus avoiding the heating and atom loss, induced from magnetic field ramp across a Feshbach resonance in practice