Seeing the Forest or the Trees? Shifting Categorical Effects in Map Memory

People use spatial and nonspatial information to structure memory for an environment. Two experiments explored interactions between spatial and social categories on map memory when mediated by retrieval (Experiment 1) and encoding (Experiment 2) demands. Participants studied a map depicting business locations (including proprietors' race). In Experiment 1, participants completed two memory tasks, one globally focused and the other locally focused. The global task compressed, while the local task expanded, within-category similarity. Furthermore, processing styles carried over to the subsequent task. Experiment 2 emphasized either the spatial or social category during encoding, which increased that category's weighting in memory. These results extend the work of Maddox, Rapp, Brion, and Taylor, suggesting that retrieval and encoding demands can shift how these categories affect spatial memory.     

Heading south with a north-up map: A choice processing analysis of map alignment effects

This study employed an information accumulation model of choice reaction times to investigate alignment effects in mental representations of maps. University students studied a map from a single orientation (with north at the top). In a subsequent two-choice reaction time task, the students’ spatial knowledge of the map was assessed employing spatial left/right judgments, which were made from imagined perspectives that were either north-aligned or south-aligned. Data showed a standard alignment effect, favoring north- over south-aligned trials. To examine the locus of this effect, data were fit using the Linear Ballistic Accumulator (LBA) model of speeded decisions (Brown & Heathcote, 2008). Of interest were three model parameters: drift rate, the speed at which evidence accumulates toward a response; response threshold, the amount of evidence demanded from the decision maker before selecting a response; and non-decision time, the time consumed by pre- and postdecisional processes. The best-fitting model suggested that non-decision time accounted for the alignment effect. The difference in non-decision time between north and south-aligned judgments suggests a mental alignment stage on south-aligned trials, accounting for the longer reaction times for judgements misaligned with the presented north orientation of the map.     

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.     

Initial moments of adaptation to microgravity of human orientation behavior, in parabolic flight conditions

The first ethological studies of astronauts' adaptation to microgravity dealt with the behavioral strategies observed during short-term space missions. No attempts had however been made to consider the initial moments of adaptation dynamics, when the subject is first submitted to conditions allowing body orientations in the full three dimensions of space. The present experimental approach was both longitudinal and transversal. It consisted of analysing, during a goal-directed orientation task in parabolic flight, the orientation behavior of 12 subjects with a past experience of 0, 30 or more than 300 parabolas. During each microgravity phase, the subjects were asked to orientate their bodies and touch, with the dominant hand, four coloured targets arranged inside the aircraft.

Results showed that for inexperienced subjects, the time between two target contacts was longer than experienced subjects. They often failed to reach all targets in the series during the first parabolas. They showed right-left confusion and a preference for the “up-down” vertical body orientation. Their performance, described by the efficiency of orientation in all three dimensions, improved over time and according to the level of experience. The results are discussed for the spontaneous, preliminary and integrative stages of adaptation, emphasizing new relationships between the body references and those of the surroundings. Such experiences lead the subject to develop a new mental representation of space.     

基于GPU的干涉测量VDIF格式数据编帧方法*

为提高深空测控网VLBI基带转换器灵活性和多种数据格式适应能力,设计一种基于GPU的VDIF格式数据编帧方法。基于CUDA并行运算架构开发符合VDIF规范的帧头计算模块、多通道单线程编帧模块和多通道多线程编帧模块。为了实现编帧过程效率的优化,设计基于纹理缓存查找表的数据量化方法和基于流式架构的多帧信号异步编帧方法。试验验证表明,设计的编帧方法结果正确,高效可靠,有望为我国深空测控干涉测量数据记录系统参与国际VLBI联合观测提供有效的支持。     

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.     

The dialogic model: representing human diversity in messages to extraterrestrials

A Dialogic Model of constructing a unified reply message is suggested in which differences between perspectives are valued, rather than minimized. In this model, a diversity of views is seen as a virtue. Consensus in the broad sense of agreeing to include multiple perspectives is encouraged, while consensus in the narrow sense of everyone agreeing about all parts of the message is seen as overly restrictive, if not impossible. In the Dialogic Model, even perspectives that are irreconcilable with one another might be included in a single reply. Drawing upon multiple perspectives allows us to expand beyond our own preconceptions, gives extraterrestrials several ways to understand our views of the world, and portrays the breadth of human concerns.Seven benefits of beginning work on a reply message immediately are identified: (1) concretely understanding the challenge of creating an adequate reply; (2) helping decode messages from extraterrestrials; (3) creating interstellar compositions as a new form of art; (4) having a reply ready in case we receive a message; (5) providing a sense of concrete accomplishment; (6) preparing for an active search strategy; and (7) gaining public support for SETI.     

Human Path Integration by Optic Flow

Path integration or 'dead reckoning' is the ability to keep track of relative position using self-motion signals that convey information about speed and direction of movement. Most animal species, including humans, exhibit some degree of path integration capability and neurophysiological studies have demonstrated that self-motion signals are sufficient to update internal representations of both position and orientation. In the present study, human subjects were required to monitor their position or orientation on the basis of unstructured optic flowfields. Trials were conducted at different speeds to examine the accuracy of path integration and rates of random error accumulation, and at two different head azimuths to prevent a confounding strategy of position updating based primarily on tracking changes in the angular declination of distant landmarks with respect to the horizon. Participants integrated the speed of visual motion to update accurately a representation of their position and orientation within the environment. Consistent with the characteristics of real-world path integration, errors accumulated linearly with the magnitude of position and orientation estimation. We conclude that coherent optic flowfields provide a sufficient basis for humans to keep track of their position and orientation relative to remembered landmarks.     

基于目标加速度方向观测的微分对策制导律

针对延迟信息条件下的机动目标拦截问题,研究了一种考虑目标加速度方向观测的微分对策制导律。首先,针对引入目标方向观测信息末制导博弈问题,建立了微分对策数学模型。随后,利用状态依赖黎卡提方程求解微分对策问题,得到包含无延迟目标机动项的微分对策制导律,可以更为有效地拦截机动目标。最后,在延迟信息条件下,利用目标加速度方向观测的方法补偿延迟的目标加速度,再将补偿后的目标加速度信息取代无延迟的目标加速度,得到延迟信息条件下考虑目标加速度方向观测的微分对策制导律。仿真结果表明,新的制导律可以在延迟信息条件下有效地拦截机动目标。     

Estimate of accuracy of determining the orientation of the star sensor system according to the experimental data

The BOKZ-M60 star sensor (Unit for Measuring Star Coordinates) is intended for determining the parameters of the orientation of the axes of the intrinsic coordinate system relative to the axes of the inertial system by observations of the regions of the stellar sky. It is convenient to characterize an error of the single determination of the orientation of the intrinsic coordinate system of the sensor by the vector of an infinitesimal turn of this system relative to its found position. Full-scale ground-based tests have shown that, for a resting sensor the root-mean-square values of the components of this vector along the axes of the intrinsic coordinate system lying in the plane of the sensor CCD matrix are less than 2″ and the component along the axis perpendicular to the matrix plane is characterized by the root-mean-square value of 15″. The joint processing of one-stage readings of several sensors installed on the same platform allows us to improve the indicated accuracy characteristics. In this paper, estimates of the accuracy of systems from BOKZ-M60 with two and four sensors performed from measurements carried out during the normal operation of these sensors on the Resurs-P satellite are given. Processing the measurements of the sensor system allowed us to increase the accuracy of determining the each of their orientations and to study random and systematic errors in these measurements.     

An Artificial Neural Network That Uses Coarse Allocentric Coding of Direction to Represent Distances Between Locations in a Metric Space

An artificial neural network was trained to rate the distances between all possible pairs taken from a set of thirteen different cities on the map of Alberta. After learning to solve this problem, the internal structure of the network was analyzed. It was found that in spite of the fact that the network was trained to rate distances, the hidden units in the network were not sensitive to distance at all. Instead, it was found that each hidden unit could be located at a particular latitude and longitude on the map of Alberta, and that at this location each hidden unit was associated with a specific heading. Each hidden unit measured the bearing of each city relative to the hidden unit's heading, and when a stimulus was presented to the network, the hidden units combined the two city bearings and generated an activity level based on this combination. The output units of the network generated an accurate distance rating by combining the directional signals that were being computed by the hidden units. These results are discussed in terms of their implications for theories about cognitive maps, in particular the modularization of distance measurements from directional measurements.     

Multiple Systems for Spatial Imagery: Transformations of Objects and Bodies

Problem-solving often requires imagining spatial changes. Object-based transformations allow imagining an object in a different orientation. Perspective transformations allow imagining changes in one's viewpoint. Three experiments tested the hypothesis that these two transformations are dissociable and specialized for different situations, by manipulating instructions and task parameters and measuring response times, errors, and introspective reports. Human experience with small objects such as telephones and clothes irons consists mostly of manipulation or observed manipulation, which is characterized by object-based transformations. Consistent with this experience, when participants made judgments about small manipulable objects, they showed a strong tendency to use object-based transformations. Experience with human bodies is more varied, including both object-like interactions and interactions in which one must estimate another's perspective. Accordingly, when making judgments about pictures of bodies, participants' selection of a spatial transformation depended on the type of judgment that needed to be made. When instructions violated these natural mappings, performance was impaired. These data argue for the view that multiple spatial transformation systems evolved to solve different spatial reasoning problems.     

Navigation in outdoor environments as an embodied,social, cultural,and situated experience: An empirical study of orienteering

This study investigated novices' “lived experiences” of navigation within the sport of orienteering from an enactive and phenomenological approach. The objective was to qualitatively characterize elements of task-related situations that were meaningful for orienteers. The results showed that the participants continuously made judgments about the reliability of their estimations about whether they were on “the right route” on the course. When the participants judged that they were only approximately on the right route or were unable to locate themselves, elements of the situation other than map and terrain features became meaningful for them. These results demonstrate that, for novice orienteers, navigation activity must extend beyond navigation as a logical, computational way-finding problem to include embodied, social, cultural and situated dimensions.     

Experiments to Examine the Situated Nature of Geoscientific Concepts

ABSTRACT

Ontologies are being developed in many geoscientific domains. They are typically populated with two types of concepts: upper-level concepts that apply across many or all domains, and domain concepts that apply only within a specific domain. Previous work has refined this distinction by identifying a particular type of domain concept, called a situated concept, which is dependent on specific processes (natural, social, scientific, or possibly machine) for its meaning and is instantiated amongst entities within a specific geographical and historical context. In this paper we present new support for situated geoscientific concepts, building on our previous research that argues for the importance of situations in the development and use of concepts related to geoscientific field mapping. The new results are obtained by using statistical techniques to further analyze three geologists' field data over time, to better test the hypothesis that the concepts developed by the geologists to classify objects on the map are in fact situated. The field data are compared to each other, and to the concepts developed by the team. Differences found between and within individuals' data for three map concepts provide strong support for the idea that the concepts are variably influenced by data, theory, and natural and human situations. From this increased corroboration of situated concepts we suggest two implications for domain ontologies: (1) a delineation between situated domain concepts and non-situated domain concepts; and (2) recognition that representation of reliable meaning involves the capture of historical and geographical context for situated concepts.     

External Cue Effects on Memory for Spatial Location within a Rotated Task Field

Abstract

We propose a mathematical model of the Path Integration (PI) process. Its core assumption is that orientations of a path are summarized by circular probability distributions. We compare our model with classical, deterministic models of PI and find that, although they are indistinguishable in terms of information encoded, the probabilistic model is more parsimonious when considering navigation strategies. We show how sensory events can enrich the probability distributions memorized, resulting in a continuum of navigation strategies, from PI to stimulus-triggered response. We analyze the combination of circular probability distributions (e.g., multicue fusion), and demonstrate that, contrary to the linear case, adding orientation cues does not always increase reliability of estimates. We discuss experimental predictions entailed by our model.     

Discovering the basic strategic orientation of big space agencies

The aim of this paper is to identify the basic strategic orientations of some of the world's main space agencies. This study focuses on the Brazilian, French, European, Japanese, Indian and Russian agencies. Basic strategic orientations indicate the real space exploration objectives of large countries. This is useful because there are some ambiguous areas in the formal strategic documents published by these agencies. The results highlight the common objectives of the agencies studied, which is to have an important role in international political leadership even considering the specific objectives related to the economic and social contexts of the individual countries.     

单次任务中主动清除多块碎片的仿真分析

针对国内外空间活动产生的碎片,文章采用多脉冲推力作用下的轨道机动仿真方法,在主要考虑总速度增量为2 km/s的约束条件下,计算碎片清除所需要的速度增量、任务时间以及清除个数。仿真结果表明,单次任务可以清除12块分布比较集中的碎片。研究结果可为我国今后空间碎片清扫任务的设计提供参考依据。     

Relationships between orientation, movement and posture in weightlessness: preliminary ethological observations

Weightlessness in man induces changes in astronaut orientations and consequently in his patterns of movements and postures. An ethological method has been used to describe the "overall" spontaneous behaviour of astronauts as seen from video recordings made during Space Flights. The work has consisted in analysing the relationships between orientation, movement and posture as an indication of a motor adaptative reorganization in such a situation. The results obtained lead us to consider three different aspects: (1) Orientation references. The astronaut orientates himself with reference to the Space Shuttle's internal structure; the increase of visual activity confirms the choice of the retinal vertical as frame of reference. (2) Motor coordination. The main data reveals a decrease in motor stereotypes by the diversity of motor acts observed and the importance of the link between orientation and posture described as follows: slightly inclined forward position, with legs flexed at about 135 degrees. (3) Cognitive references. There appears to be a new organization of the cognitive image of the body scheme, the missing vestibular information being supplied by peripheral vision instead which could play a role in the astronaut's perception of his own movement.