Selecting a reference frame

Reference frames are representations that parse space. In the case of spatial terms, reference frames mediate the mapping of linguistic expressions onto spatial configurations of objects. In the sentence ``The fly is above the cat,' ``above' is defined with respect to a reference frame that is imposed on the cat. Different types of reference frames can be used to define spatial terms, each based on a different source of information. For example, gravity, the orientation of objects in the scene or the orientation of the viewer can all be used to set the orientation of a reference frame. When these reference frames disagree (because the viewer is reclining or because the objects in the scene are overturned), there are competing definitions for the spatial term, resulting in the need for reference frame selection. The purpose of this paper is to review a line of research that examines reference frame selection in the context of spatial language. This work shows that all reference frames are initially active and assign a direction to a spatial term. Moreover, this activation is automatic, and is followed by the selection of a single reference frame, with selection accompanied by inhibition of the non-selected frames. Parallels between reference frame selection in language and in perception and attention are discussed.     

Prioritized Spatial Updating in the Intrinsic Frame of Reference

In order to maintain valid situation awareness, people need to update the spatial representations of their surroundings as objects, including themselves, move. The present study investigates the properties of spatial updating in the intrinsic frame of reference, where spatial relations are represented with respect to an external object (other than the viewer self) with an intrinsic reference direction. Three experiments were conducted using a task of direction pointing. It was found that given a relatively stable intrinsic reference direction, responses to a small number of salient objects were faster than responses to non-salient objects (Experiment 1 and Experiment 3). The salience effect disappeared when the intrinsic reference direction was no longer stable (Experiment 2). Furthermore, all three experiments revealed a type of orientation dependence similar to that found in egocentric spatial updating. Our results indicate that spatial updating in the intrinsic reference system can be easy only if a fixed reference direction is maintained and the number of objects that need to be tracked is limited.     

The Psychological Validity of Qualitative Spatial Reasoning in One Dimension

One of the central questions of spatial reasoning research is whether the underlying processes are inherently visual, spatial, or logical. We applied the dual task interference paradigm to spatial reasoning problems in one dimension, using Allen's interval calculus, in order to make progress towards resolving this argument. Our results indicate that spatial reasoning with interval relations is largely based on the construction and inspection of qualitative spatial representations, or mental models, while no evidence for logical proofs of derivations or the involvement of visual representations and processes was found.     

Children's control of reference systems in spatial tasks: Foundations of spatial cognitive skill?

Two experiments are presented, one that focused on the abilities of 3- through 8-year-old children to use frames of reference as means for solving a search task in a small-scale perceived space and one that focused on the abilities of 8- through 11-year-old children to use different frames of reference to answer questions about the locations of objects in an environment they had read about. Experiment 1 revealed developmental improvement in the consistent application of object-, place-, and viewer-based frames of reference, with scale of space impacting the pattern of age-related improvement. Experiment 2 showed that young readers' first successes with switching from one reference system to another in representational space involved a vantage point perspective, a viewer-based ``gaze tour' of a small-scale area. Although disparate in focus and method, the studies point to the need for a new theoretical framework for examining developmental issues in the application of spatial frames of reference.     

Space,Language and Ontology: A Response to Davis

Abstract

Ernest Davis' article “Qualititative Spatial Reasoning in Interpreting Text and Narrative” discusses challenges that the interpretation of natural language appears to raise for the formalization of commonsense spatial reasoning. Davis finds these to be of “surprising logical complexity,” but also “erratic” in that they do not show a logical structuring of the problem space that could guide productive research. In this response I argue that much of the apparent lack of structure Davis laments is due to the very style of formal modeling he pursues. By augmenting logical considerations with substantial input from other disciplines and by adopting a heterogeneous and modular approach to formalization, I suggest that the problem space is by no means as ill-structured as Davis presents it.     

Qualitative Spatial Reasoning in Interpreting Text and Narrative

Abstract

Simple natural language texts and narratives often raise problems in commonsense spatial knowledge and reasoning of surprising logical complexity and geometric richness. In this article, I consider a dozen short texts—five taken from literature, the remainder contrived as illustrations—and discuss the spatial reasoning involved in understanding them. I conclude by summarizing their common features, and by tentatively drawing some morals for research in this area.     

Mereological inheritance

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.     

Egocentric frames of reference used for the retrieval of survey knowledge learned by map and navigation

Two experiments are reported that use a ``point-to-unseen-targets' task to study the role of egocentric reference frames in the retrieval of survey knowledge learned from either studying a map or navigating an environment. In Experiment 1, performance was generally consistent with the hypothesis that map knowledge is retrieved using a frame of reference centered on the eye, characterized by (a) a fixed orientation in a ``frontal representational plane' and (b) equal access to spatial relations both in front of, or above, and behind, or below, a right-left retrieval axis. The results of Experiment 2 were consistent with the hypothesis that environment knowledge is retrieved within a frame of reference centered on the body, characterized by (a) flexible orientation within a ``transverse representational plane' and (b) privileged access to spatial relations located in front of the right-left retrieval axis in representational space. Both types of knowledge function as if they preserve information about the Euclidean angles connecting elements in physical space.     

改进模拟退火算法的喷管动力学模型修正

为获得液体火箭发动机喷管高精度的结构动力学有限元模型，提出一种基于改进模拟退火算法（Improved Simulation Annealing Algorithm，ISAA）的有限元模型修正方法。首先，将复杂的薄壁夹层板喷管等效为复合材料层合壳，建立喷管的参数化有限元模型；在此基础上，以结构模态参数为参考基，构造出联合使用模态频率及模态振型的目标函数，并运用灵敏度分析提取设计变量，从而建立其优化模型；提出带记忆、局部搜索功能的改进模拟退火算法，运用ISAA在设计空间进行多目标全局寻优；最后，采用基于MSC Patran/Nastran软件平台二次开发的结构动力学模型修正软件ZDXZ V1.0进行模型修正，并对模型修正方法的有效性进行了校验。结果表明，修正后喷管的前3阶计算模态频率与试验值相对误差小于2%，振型相关性最小MAC值大于0.9，大大提升了喷管模型的动力学符合性，模型精度满足工程应用要求；表明所述模型修正策略的有效性，该方法具有高效、强鲁棒性等特点，适合于大型复杂结构的模型修正。     

Environmental reference systems for large-scale spaces

Human navigation in well-known environments is guided by stored memory representations of spatial information. In three experiments (N = 43) we investigated the role of different spatial reference systems when accessing information about familiar objects at different locations in the city in which the participants lived. Our results indicate that two independent reference systems underly the retrieval of spatial knowledge. Environmental characteristics, e.g., the streets at an intersection, determine which headings are easier to imagine at a given location and lead to differences in accessibility of spatial information (orientation-specific behavior). In addition, access to spatial information depends on the relative direction of a location with respect to the imagined heading, such that information about locations imagined in front of oneself is easier to access than about locations towards the back. This influence of an egocentric reference system was found for environmental knowledge as well as map-based knowledge. In light of these reference system effects, position-dependent models of spatial memory for large-scale environments are discussed. To account for the simultaneous effect of an environmental and an egocentric reference system, we present a 2-level model of spatial memory access.     

Spatial Reference in Linguistic Human-Robot Interaction: Iterative,Empirically Supported Development of a Model of Projective Relations

The aim of our research is to enable spontaneous and efficient spatial reference to objects in human-robot interaction situations. This paper presents the iterative, empirically based design of a robotic system that uses a computational model for identifying objects on the basis of a range of spatial reference systems. The efficiency of the system is evaluated by two successive empirical studies involving uninformed users. The linguistic analysis points to the striking variability in speakers' spontaneous strategies and preferences, and it motivates a number of modifications of the computational model.     

Who are the SETI sceptics?

Search for ExtraTerrestrial Intelligence (SETI) is now more than half a century old and has provoked enough discussion on technical, philosophical, and popular level, much of it critical. Historically, the criticism of SETI has been strong enough to heavily influence the course of research, so that there is a significant interest in discerning the nuances and fine points of critical argumentation. In this paper, I outline the two major forms of SETI scepticism, “fundamentalist” and “instrumentalist,” which are often conflated in the published literature, both technical and popular. Precise delineation between these two types of scepticism is important for future research as a part of a wider taxonomic project, the build-up of SETI theory, as well as for smooth joining of SETI with the ongoing astrobiological revolution. Resolving the confusion in this respect is likely to lead to an improved atmosphere and heightened public image of future SETI searches and related activities.     

Mental representation of spatial cues in microgravity: Writing and drawing tests

Humans have mental representation of their environment based on sensory information and experience. A series of experiments has been designed to allow the identification of disturbances in the mental representation of three-dimensional space during space flight as a consequence of the absence of the gravitational frame of reference. This NASA/ESA-funded research effort includes motor tests complemented by psychophysics measurements, designed to distinguish the effects of cognitive versus perceptual-motor changes due to microgravity exposure. Preliminary results have been obtained during the microgravity phase of parabolic flight. These results indicate that the vertical height of handwritten characters and drawn objects is reduced in microgravity compared to normal gravity, suggesting that the mental representation of the height of objects and the environment change during short-term microgravity. Identifying lasting abnormalities in the mental representation of spatial cues will establish the scientific and technical foundation for development of preflight and in-flight training and rehabilitative schemes, enhancing astronaut performance of perceptual-motor tasks, for example, interaction with robotic systems during exploration-class missions.     

模型修正中一种特殊广义逆的性质与功能

本文对一种特殊的广义逆矩阵在模型修正中使用时可能具有的性质与功能给予了间接的论证,从而为这种广义逆的进一步应用给予了提示。该论证表明,这种广义逆不仅具有增补方程个数的作用,而且还具有对修正模型的参考基增补高阶理论模态信息的功能。通过本文论证,文[2][4]之解的唯一性问题明确解决了,即为一个实用完备模态空间中的确定解。     

资源三号卫星廊坊地区遥感数据的融合处理

本文以资源三号卫星河北省廊坊地区2A级全色遥感影像和多光谱影像数据为基础,采用遥感数字图像处理软件ERDASIMAGINE进行了研究区域的提取,并对提取的感兴趣区进行了几何校正,即图像配准处理,然后进行了融合处理,分别采用了空间增强的分辨率融合算法、改进IHS分辨率融合算法以及小波分辨率融合算法,通过和融合前的影像进行对比,融合后的影像既保留了多光谱影像的丰富的波谱信息,同时具有了全色影像的高空间分辨率的特征,最后对比三种融合算法,得出改进的IHS分辨率融合算法效果最佳。     

基于不完整正弦基础激励响应数据的模型修正方法

文章直接应用航天器正弦振动试验所获取的结构动力学特性响应数据,开展了模型修正方法的研究。在试验数据不完整时,需进行模型缩聚。首先对比分析了Guyan缩聚和IRS缩聚方法的优缺点和适用范围;然后以缩聚后模型为基础,推导了基于基础激励响应数据的模型修正方法;最后以GARTEUR桁架结构的不完整的基础激励试验数据为基础对归一化的结构参数进行修正。结果表明:IRS缩聚模型修正后对模态频率具有良好的复现能力和预示能力,对响应曲线的修正也得到了明显改善。     

Monitoring Object Orientation: Effects of Layout Complexity,Viewpoint Changes,and Object Function

Spatial short-term memory for single target positions is subject to distortions which depend on the spatial layout of visual landmarks. Here, participants had to reproduce the positions of briefly presented targets in the context of three-landmark configurations presented in various orientations. Symmetry properties of distortional patterns were determined by the intrinsic reference system of the landmark configuration as well as by the environment-or body-centered vertical axis. Symmetry was best about the cardinal axes of the landmark system irrespective of their orientation, but symmetry of non-cardinal axes was enhanced when these axes were aligned with the extrinsic vertical. Results are inconsistent with most current models of spatial memory distortions but in line with models explaining distortions in terms of attentional processes in topographical neuronal networks.