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221.
针对会计信息失真现象的泛滥,首先分析了会计信息失真的现状,在此基础上主要从经济学的角度分析了由于市场经济制度不完善、产权制度不完善和激励与约束机制不配套所带来的会计信息失真,最后提出从完善市场经济制度、完善产权制度和完善激励与约束机制等方面防范会计信息失真。  相似文献   
222.
Abstract

This research uses a novel integration paradigm to investigate whether target locations read in from long-term memory (LTM) differ from perceptually encoded inputs in spatial working-memory (SWM) with respect to systematic spatial error and/or noise, and whether SWM can simultaneously encompass both of these sources. Our results provide evidence for a composite representation of space in SWM derived from both perception and LTM, albeit with a loss in spatial precision of locations retrieved from LTM. More generally, the data support the concept of a spatial image in working memory and extend its potential sources to representations retrieved from LTM.  相似文献   
223.
ABSTRACT

The goal of this paper is to present a logic-based formalism for representing knowledge about objects in space and their movements, and show how this knowledge could be built up from the viewpoint of an observer immersed in a dynamic world. In this paper space is represented using functions that extract attributes of depth, size and distance from snapshots of the world. These attributes compose a novel spatial reasoning system named Depth Profile Calculus (DPC). Transitions between qualitative relations involving these attributes are represented by an extension of this calculus called Dynamic Depth Profile Calculus (DDPC). We argue that knowledge about objects in the world could be built up via a process of abduction on DDPC relations.  相似文献   
224.
天空飞行与地面风洞实验动态气动相关中的雷诺数影响   总被引:1,自引:0,他引:1  
近10余年来,在3个动态气动专题领域内,地面风洞自由飞实验与对应的天空飞行器的绕流雷诺数虽然相差1~2个量级,但风洞自由飞实验结果多次预测或再现了天空飞行器出现的对飞行安全、飞行性能产生严重影响、其它地面风洞实验方法难以预测或再现的这3个专题领域内的动态气动特性,这至少为3个专题领域内天地动态气动相关中的雷诺数影响,提供了一个新的理解。  相似文献   
225.
美育在思想政治教育中的地位与作用   总被引:1,自引:0,他引:1  
从德育和美育的关系,美育和功能讨论美育在思想政治教育中的作用,并针对当代大学生的审美误区,论述了美育在思想政治教育中的作用及进行审美教育的必要性与迫切性。  相似文献   
226.
双网格是一种基于离散几何的空间对象表示方法。与使用整数坐标系统的Realms不同,双网格使用了有限精度的有理数坐标系统。本文分析了Realms和双网格这两种空间对象表示方法对空间拓扑性的影响以及各自的优缺点,讨论了基于双网格和主存技术实现空间管理子系统的方法。本文还介绍了空间管理子系统与PostgreSQL的集成技术,并设计和实现了基于双网格的空间分析DBMS-SADBSⅡ。该系统能够有效地管理空间数据和非空间数据,并具有ROSE代数定义的全部空间分析操作功能。  相似文献   
227.
Qualitative spatial reasoning (QSR) is often claimed to be cognitively more plausible than conventional numerical approaches to spatial reasoning, because it copes with the indeterminacy of spatial data and allows inferences based on incomplete spatial knowledge. The paper reports experimental results concerning the cognitive adequacy of an important approach used in QSR, namely the spatial interpretation of the interval calculus introduced by Allen (1983). Knauff, Rauh and Schlieder (1995) distinguished between the conceptual and inferential cognitive adequacy of Allen's interval calculus. The former refers to the thirteen base relations as a representational system and the latter to the compositions of these relations as a tool for reasoning. The results of two memory experiments on conceptual adequacy show that people use ordinal information similar to the interval relations when representing and remembering spatial arrangements. Furthermore, symmetry transformations on the interval relations were found to be responsible for most of the errors, whereas conceptualneighborhood theory did not appear to correspond to cognitively relevant concepts. Inferential adequacy was investigated by two reasoning experiments and the results show that in inference tasks where the number of possible interval relations for the composition is more than one, subjects ignore numerous possibilities and interindividually prefer the same relations. Reorientations and transpositions operating on the relations seem to be important for reasoning performance as well, whereas conceptual neighborhood did not appear to affect the difficulty of reasoning tasks based on the interval relations.  相似文献   
228.
    
In recent investigations of Spatial Reasoning, SpatialKnowledge Representation, and Geographic Information Systems, asignificant effort has been spent by many scholars of the areaabout the problem of representing properties of spatial objects bymeans of logical theories.An analogous effort has been the problem of analyzingthe qualitative relations which can be established between twospace regions. These investigations have led to a generalframework of the field known by the term ``mereo-topology'.Though both the above mentioned approaches have proved to besuccessful in the investigation of formal and practically relevantaspects of spatial objects, no attempt has been carried out in the direction of integrating the approaches and looking at the relationshipbetween a general logical theory of space and mereo-topology from an analytical point of view, in particular for exploiting thecombinatorial behaviour of such an integrated model.This paper intends to fill the gap and analyze the behaviour ofspatial formulae of a logical theory of space as objects which canbe classified based on the behaviour they exhibit with respect tothe parts and supertparts of the regions where they are true. Wename these categories of behaviourinheritance modalities.  相似文献   
229.
针对现有异步空间配准算法在目标机动时无法准确估计传感器系统误差的问题,研究了一种基于内插外推时间配准的异步传感器空间配准算法.该算法首先采用内插外推时间配准算法实现两传感器的数据同步,随后根据时间配准结果构建伪量测方程.不同于其他文献根据目标状态向量和时间差求解加权系数,从而构造与目标运动状态无关的伪量测方程的方法,该算法的伪量测方程构建过程与目标状态向量无关,且可以证明由时间配准结果构造的伪量测也与目标状态无关.因此该算法可有效解决目标机动条件下的异步传感器空间配准问题.仿真实验验证了该算法在目标作蛇形机动的条件下仍然可准确地对传感器的系统误差进行估计.  相似文献   
230.
    
Empirical relations among age, general spatialability as assessed by psychometric tests,wayfinding-related skills as assessed byexperimental tasks in the laboratory,environmental layout learning as assessed in afield experiment, and wayfinding behavior asobserved in a field experiment were modeled ina study involving 120 younger and 120 olderadults. The best-fitting model showed thatage-related differences in learningenvironmental layout were significantly, butnot exclusively, mediated by a single abilityfactor defined by psychometric tests. Knowledge of environmental layout was theexclusive mediator between general spatialability and wayfinding behavior. Thus, agedifferences in psychometric test performancewere found to be a major factor in accountingfor aging-related decline in learningenvironmental layout, but other variables notassessed in this study also play a significantrole.  相似文献   
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