Mental spatial transformations of objects and perspective

This study sought evidence for the independenceof two classes of mental spatialtransformation: object-based spatialtransformations and egocentric perspectivetransformations. Two tasks were designed toselectively elicit these two transformationsusing the same materials, participants, andtask parameters: one required same-differentjudgments about pairs of pictures, while theother required left-right judgments aboutsingle pictures. For pictures of human bodies,the two tasks showed strikingly differentpatterns of response time as a function ofstimulus orientation. Moreover, acrossindividuals, the two tasks had differentrelationships to psychometric tests of spatialability. The chronometric and individualdifference data converge withneuropsychological and neuroimaging data insuggesting that different mental spatialtransformations are performed by dissociableneural systems.     

Influence of Map Design,Individual Differences,and Environmental Cues on Wayfinding Performance

This exploratory study investigated the effects of map design, individual differences, and environmental cues on wayfinding performance in an outdoor recreational area. Six maps, with three contour representations and two color codes, were used to determine how map design influences wayfinding. Four individual differences: gender, experience in map usage (experience vs. novice), handedness, and cultural difference (local vs. international), were used to predict wayfinding performance. The study area consisted of a trail park with ten junctions, where three of the junctions had signs, as environmental cues to aid users. Multiple regression analyses and logistic regression analysis were performed to predict the total time of completion, time for decision-making, accuracy of decision-making, and total time deviated from route. Results showed that only cultural difference and signage significantly predicted decisionmaking accuracy, and cultural difference was a significant predictor of total time deviated from route. Design implications for use of cues and wayfinding are discussed. In addition, recommendations for maps, trail networks, and environmental design are provided.     

Wayfinding Performance in and the Spatial Knowledge of a Color-coded Building for Adults and Children

The study reported here investigates the effect color has on the performance in a wayfinding task,the wayfinding strategies used and the acquisition of survey knowledge of a total of sixty participants: twenty second graders,sixth graders, and adults each. All participants had to find their way to a goal in a virtual environment with either a colored or a gray ground. After that,they had to find the shortest way from the start position to the goal in two consecutive trials,to draw a sketch map of the maze,and to mark the position of the goal figure in an overview of the maze. The results showed that color helped all participants to improve their performance in the wayfinding task, influenced the use of some wayfinding strategies but did not improve the acquisition of survey knowledge. Furthermore, there was a developmental achievement from second graders to adults. The results implicate firstly that children and adults similarly rely on the structuring of space through color when navigating through an unfamiliar large-scale environment,and secondly that there is a dissociation between wayfinding behavior and spatial knowledge.     

Learning Routes from Visualizations for Indoor Wayfinding: Presentation Modes and Individual Differences

Abstract

Participants (N = 78) studied a visualization of a route through a complex building and walked that route in the real building without further assistance. Erroneous turns on the route as well as indicators of uncertainty such as hesitations were assessed. Three types of route visualizations were compared: (1) an allocentric, map-based visualization with the route indicated in floor maps, (2) an ordered sequence of pictures of decision points shown from the egocentric perspective, and (3) an animation showing a virtual walk of the route from the egocentric perspective. In addition to the experimental variation, gender differences, differences in visual-spatial abilities and differences in self-reported wayfinding strategies were considered as predictor variables. Wayfinding performance did not differ between allocentric (map) and egocentric (decision point pictures and animation) visualizations. However, wayfinding performance was better with animated than with static egocentric visualizations. Individual differences in the ability to encode visual-spatial information from the visualization played a critical role for route learning. Self-reported sense of direction related to egocentric wayfinding strategies also predicted wayfinding performance. Gender differences were attributable to differences in visual-spatial abilities and egocentric wayfinding strategies. Interactions between visualizations and individual differences were not found. It is concluded that animations of virtual walks are suitable to convey route information in complex buildings. Successful acquisition of route knowledge from maps is possible but might depend on the comprehensibility of the structure of the building.     

Taxonomy of Human Wayfinding Tasks: A Knowledge-Based Approach

Abstract

Although the term “Wayfinding” has been defined by several authors, it subsumes a whole set of tasks that involve different cognitive processes, drawing on different cognitive components. Research on wayfinding has been conducted with different paradigms using a variety of wayfinding tasks. This makes it difficult to compare the results and implications of many studies. A systematic classification is needed in order to determine and investigate the cognitive processes and structural components of how humans solve wayfinding problems. Current classifications of wayfinding distinguish tasks on a rather coarse level or do not take the navigator's knowledge, a key factor in wayfinding, into account. We present an extended taxonomy of wayfinding that distinguishes tasks by external constraints as well as by the level of spatial knowledge that is available to the navigator. The taxonomy will help to decrease ambiguity of wayfinding tasks and it will facilitate understanding of the differentiated demands a navigator faces when solving wayfinding problems.     

Selection of Salient Features for Route Directions

People navigating in unfamiliar environments rely on wayfinding directions, either given by people familiar with the place, or given by maps or wayfinding services. The essential role of landmarks in human route communication is well-known. However, mapping the human ability to select landmarks ad hoc for route directions to a computational model was never tried before. Wayfinding services manage the problem by using predefined points of interest. These points are not automatically identified, and they are not related to any route. In contrast, here a computational model is presented that selects salient features along a route where needed, e.g., at decision points. We propose measures to formally specify the salience of a feature. The observed values of these measures are subject to stochastical tests in order to identify the most salient features from datasets. The proposed model is implemented and checked for computability with a use case from the city of Vienna. It is also crosschecked with a human subject survey for landmarks along a given route. The survey provides evidence that the proposed model selects features that are strongly correlated to human concepts of landmarks. Hence, integrating the selected salient features in wayfinding directions will produce directions with lower cognitive workload and higher success rates, compared to directions based only on geometry, or on geometry and static points of interest.     

Influence of estimation errors on wayfinding-decisions in unknown street networks – analyzing the least-angle strategy

The least-angle strategy is a common wayfinding method that can be applied in unknown environments if the target direction is known. The strategy is based on the navigator's heuristic to select the street segment at an intersection which is most in line with the target direction. To use this strategy, the navigator needs to know the angles between the target direction and the street segments leading out from the intersection. If the direct view to the target is blocked and the target vector cannot be perceived, the target direction that is needed for the decision process is based on the agent's believed position and orientation (estimated through path integration). The agent's believed position and target direction are distorted by human errors in estimation of distances and directions, mainly affecting the path integration process. In this paper we examine how human estimation errors of distance and rotation influence the decision behavior in the wayfinding process in an unknown street environment. To demonstrate the geometrical consequences for a specific test case, we use a simulated software agent which navigates in a simulated street environment.     

Wayfinding Through Orientation

Dominant approaches in computer-assisted wayfinding support adhere to the deeply problematic principles of turn-by-turn navigation. In this article, we suggest a new approach called “Wayfinding Through Orientation,” which supports the acquisition of spatial knowledge and cognitive mapping for advancing the user’s spatial orientation. Being oriented on one’s way is a prerequisite to enabling people to verify instructions and to incorporate new spatial information into their existing knowledge structure. In three studies described in this article we first present empirical evidence that people can be supported in survey knowledge acquisition through suitable wayfinding instructions. Consequently, we explore orientation information in human wayfinding instructions. Finally, we outline how orientation information can be communicated within a prototypically implemented navigation assistance system.     

航天器公用空间搭载试验平台设计

我国航天器搭载试验包括空间材料实验、航天医学实验和航天新技术验证试验,具有数据量大、需要实时传输、工作模式多样等特点。文章根据试验项目的需求,设计了应用于低轨道航天器的支持各类空间搭载试验项目的公用试验平台。地面测试验证和在轨运行情况表明,该平台在不影响飞行器平台安全的同时,满足了对试验项目的工作控制、遥测监视及试验数据传输管理的任务要求。     

Timing and sex effects on the “Spatial Orientation Test”: A World War II map reading test

The present study aimed to document the psychometric properties of a recently declassified map reading test used in World War II, known as the Spatial Orientation Test (SOT), which measures mostly the ability to match map and aerial images. We also examined the influence of timing conditions and sex of the participants as correlates of performance. A total of 101 participants (41 males, 60 females) completed the SOT, along with other spatial tests and spatial affect scales (tapping spatial anxiety and confidence). Results showed a significant male advantage on this rediscovered map reading test. Additionally, timing affected overall performance but not the magnitude of sex differences. Finally, significant correlations were found between the SOT and other spatial tests and scales. The processes underlying this test and its potential for future use are discussed.     

Conceptual study and key technology development for Mars Aeroflyby sample collection

Conceptual study of Mars Aeroflyby Sample Collection (MASC) is conducted as a part of the next Mars exploration mission currently entertained in Japan Aerospace Exploration Agency. In the mission scenario, an atmospheric entry vehicle is flown into the Martian atmosphere, collects the Martian dust particles as well as atmospheric gases during the guided hypersonic flight, exits the Martian atmosphere, and is inserted into a parking orbit from which a return system departs for the earth to deliver the dust and gas samples. In order to accomplish a controlled flight and a successful orbit insertion, aeroassist orbit transfer technologies are introduced into the guidance and control system. System analysis is conducted to assess the feasibility and to make a conceptual design, finding that the MASC system is feasible at the minimum system mass of 600 kg approximately. The aerogel, which is one of the candidates for the dust sample collector, is assessed by arcjet heating tests to examine its behavior when exposed to high-temperature gases, as well as by particle impingement tests to evaluate its dust capturing capability.     

新一代运载火箭增压输送系统交叉输送技术研究

介绍了液体运载火箭和航天飞行器推进剂交叉输送技术的概念。分析了贮箱间和管路间两种交叉输送系统的原理和工作特点，以及国外如美国第二代航天飞机、三级并联火箭飞行器、宇宙神运载火箭，以及欧空局阿里安4LP运载火箭采用的交叉输送技术。阐明了交叉输送连接器和交叉增压等关键技术。对所研制的蝶型活门进行的气动螺栓分离和气动分离，以及以水为介质的交叉输送系统小比例系统试验结果表明，两种分离方案均能实现可靠分离，系统工作正常。推进剂交叉输送技术可用于改善捆绑式运载火箭和航天飞机的布局和性能。     

An Analysis of the Navigation Metaphor—And Why It Works for the World Wide Web

People use spatial metaphors when they talk about activities on the World Wide Web, such as navigating the Web, reaching one's goal, visiting a Web site, or moving back to a previous Web page. These expressions are mappings from the physical world to an application domain. We analyze why Web users conceptualize clicking on a sequence of Web links as navigation. The semantics of an object or an activity in its source domain can be defined over its behavior with a set of axioms. We propose that these axioms must also be satisfied in the target domain for an object or activity to yield a sound metaphor. We use a first-order algebraic specification language to define the semantics of navigation in the real world as a set of axioms, specify a Web navigating agent as algebra, and demonstrate that there exists a morphism between both specifications, which means that the Web agent behaves according to the set of wayfinding axioms. This suggested method is another step towards a formally grounded explanation of metaphorical mappings.     

“嫦娥一号”卫星真空热试验中的技术关键

"嫦娥一号"卫星是我国第一颗绕月探测卫星,由于其所处特殊的热环境,造成热控设计的复杂性,随之带来的是对卫星系统热控和真空热试验提出了很高的要求。该卫星在2005-2006年一年多的时间里完成了大量的整星、系统级及大部件的真空热试验,对现有的空间环境模拟试验技术是一个严峻的考验。文章分别从外热流模拟装置设计技术、热试验支架设计技术、数据测量与控制技术等方面所做的技术创新及其在"嫦娥一号"卫星系列真空热试验中的应用情况作了简要介绍。     

环境压强对NEPE推进剂单向拉伸力学行为的影响

采用单向拉伸实验,研究了不同温度、不同拉速、不同环境压强对NEPE推进剂力学行为的影响。结果表明,环境压强对NEPE推进剂力学行为的影响存在一个阈值,超过该阈值后,环境压强对最大强度的影响不大,对最大伸长率无明显影响规律。同时,采用双剪强度理论,建立了NEPE推进剂最大剪应力强度与环境压强的关系。结果表明,两者呈现较好的线性关系,根据关系式得出,在低温下推进剂最大剪应力强度对环境压强更敏感,并对该关系式的其他应用进行了简要分析。采用SEM法观测结果表明,环境压强主要在抑制颗粒脱湿、降低空穴方面有较强作用。