Perceiving affordances in virtual reality: influence of person and environmental properties in perception of standing on virtual grounds

We evaluated the perception of affordances in virtual environments (VE). In our work, we considered the affordances for standing on a virtual slanted surface. Participants were asked to judge whether a virtual slanted surface supported upright stance. The objective was to evaluate whether this perception was possible in virtual reality (VR) and comparable to previous works conducted in real environments. We found that the perception of affordances for standing on a slanted surface in virtual reality is possible and comparable (with an underestimation) to previous studies conducted in real environments. We also found that participants were able to extract and to use virtual information about friction in order to judge whether a slanted surface supported an upright stance. Finally, results revealed that the person’s position on the slanted surface is involved in the perception of affordances for standing on virtual grounds. Taken together, our results show quantitatively that the perception of affordances can be effective in virtual environments and influenced by both environmental and person properties. Such a perceptual evaluation of affordances in VR could guide VE designers to improve their designs and to better understand the effect of these designs on VE users.     

A part affordance-based approach for capturing detailed design knowledge

Design knowledge reuse is widely accepted as an effective strategy for designers to develop robust artifacts with less time and lower cost. However, there has been very little research on how to help designers capture detailed design knowledge for reuse. As a result, most detailed design knowledge still has to remain in designers’ memories as tacit knowledge, which can easily get lost due to oblivion or the mobility of designers. Therefore, this paper attempts to develop a part affordance-based approach for externalizing and capturing detailed design knowledge for effective reuse. It first introduces a part model for representing the detailed design-related information. Based on the relational theory for design, the concept, part affordance, is then employed to help designers externalize and capture various lifecycle factors that are implicit in a detailed design. Based on the affordance constraint axiom, a systematic approach is then proposed for deriving tacit design knowledge from captured part affordances through the analysis of extreme working situations. The proposed approach has been implemented as the Design Knowledge-Capturing System (DKCS). A fixture design case has been employed to illustrate the proposed approach.     

Agent-based simulation of affordance-based human behaviors in emergency evacuation

Complex cognitive processes corresponding to human control behaviors cannot be easily inferred using (1) a logical rule-based model, (2) a statistical model, or (3) an analytical predictive model. Predicting human behaviors in complex and uncertain environments like emergency evacuation is considered almost impossible (at least NP hard) in systems theory. In this paper, we explore simulating human behaviors using affordance-based finite state automata (FSA) modeling, based on the ecological concept of affordance theory. To this end, we introduce the conceptual and generic framework of affordance-based human behavior simulation developed through our previous work. Following the generic framework, formal simulation models of affordance-based human behaviors are developed, especially for emergency evacuation, to mimic perception-based dynamic human actions interacting with emergent environmental changes, such as fire. A “warehouse fire evacuation” case is used to demonstrate the applicability of the proposed framework. The human action planning algorithms in the simulation model are developed and implemented using the Adjusted Floor Field Indicators, which represent not only the evacuee’s prior knowledge of the floor layout but the perceivable information about dynamic environmental changes. The results of our simulation study verify that the proposed framework accurately simulates human fire evacuation behavior. The proposed framework is expected to capture the natural manner in which humans behave in emergency evacuation and enhance the simulation fidelity of analyses and predictions of perceptual human behaviors/responses in the systems by incorporating cognitive intent into human behavior simulations.     

Case studies of applying Gibson's ecological approach to mobilerobots

Gibson's ecological approach to perception has recently received significant attention in the robotics literature, The approach relies on the identification and application of affordances for a behaviour. However, determining suitable affordances has been treated as an art rather than a science. This paper presents a methodology for deciding whether an affordance-based approach should be pursued for a specific behaviour and for isolating a reliable affordance. Three case studies on three mobile robots are presented which used this methodology successfully. The case studies illustrate the advantages and limitations of affordances, as well as offer practical insights into applying the ecological approach     

Effects of different interaction modes on fatigue and reading effectiveness with mobile phones

Reading on touchscreen mobile devices is common in modern society. However, it is difficult to determine which interaction mode has the best reading effect when reading texts of different lengths. Using memory tests, eye-movement data analysis, and task load scale, we studied the effects of paging and vertical scrolling modes on the memory level, visual fatigue, task load, and reading speed of 28 participants reading both long and short texts. The results showed that vertical scrolling has a better memory effect than paging mode when reading short texts, but there was no difference in effect when reading long texts; the blink frequency in paging mode is higher than in scrolling mode whether reading long or short texts; no significant differences were found in reading speed in scrolling or paging mode when reading short or long texts; and in task load, the mental and temporal demands in scrolling mode were lower than in paging mode whether reading long or short texts. Considering that most current mobile readings do not differ in interaction mode according to the length of reading material, our conclusions provide valuable design recommendations to designers working on mobile reading apps.     

Goal emulation and planning in perceptual space using learned affordances

In this paper, we show that through self-interaction and self-observation, an anthropomorphic robot equipped with a range camera can learn object affordances and use this knowledge for planning. In the first step of learning, the robot discovers commonalities in its action-effect experiences by discovering effect categories. Once the effect categories are discovered, in the second step, affordance predictors for each behavior are obtained by learning the mapping from the object features to the effect categories. After learning, the robot can make plans to achieve desired goals, emulate end states of demonstrated actions, monitor the plan execution and take corrective actions using the perceptual structures employed or discovered during learning. We argue that the learning system proposed shares crucial elements with the development of infants of 7–10 months age, who explore the environment and learn the dynamics of the objects through goal-free exploration. In addition, we discuss goal emulation and planning in relation to older infants with no symbolic inference capability and non-linguistic animals which utilize object affordances to make action plans.     

Service robots in hospitals: new perspectives on niche evolution and technology affordances

Changing demands in society and the limited capabilities of health systems have paved the way for robots to move out of industrial contexts and enter more human-centered environments such as health care. We explore the shared beliefs and concerns of health workers on the introduction of autonomously operating service robots in hospitals or professional care facilities. By means of Q-methodology, a mixed research approach specifically designed for studying subjective thought patterns, we identify five potential end-user niches, each of which perceives different affordances and outcomes from using service robots in their working environment. Our findings allow for better understanding resistance and susceptibility of different users in a hospital and encourage managerial awareness of varying demands, needs, and surrounding conditions that a service robot must contend with. We also discuss general insights into presenting the Q-methodology results and how an affordance-based view could inform the adoption, appropriation, and adaptation of emerging technologies.     

The Impact of Tangible User Interfaces on Designers' Spatial Cognition

ABSTRACT

Most studies on tangible user interfaces for the tabletop design systems are being undertaken from a technology viewpoint. Although there have been studies that focus on the development of new interactive environments employing tangible user interfaces for designers, there is a lack of evaluation with respect to designers' spatial cognition. In this research we study the effects of tangible user interfaces on designers' spatial cognition to provide empirical evidence for the anecdotal views of the effect of tangible user interfaces. To highlight the expected changes in spatial cognition while using tangible user interfaces, we compared designers using a tangible user interface on a tabletop system with 3D blocks to designers using a graphical user interface on a desktop computer with a mouse and keyboard. The ways in which designers use the two different interfaces for 3D design were examined using a protocol analysis method. The result reveals that designers using 3D blocks perceived more spatial relationships among multiple objects and spaces and discovered new visuo-spatial features when revisiting their design configurations. The designers using the tangible interfaces spent more time in relocating objects to different locations to test the moves, and interacted with the external representation through large body movements implying an immersion in the design model. These two physical actions assist in designers' spatial cognition by reducing cognitive load in mental visual reasoning. Further, designers using the tangible interfaces spent more time in restructuring the design problem by introducing new functional issues as design requirements and produced more discontinuities to the design processes, which provides opportunity for reflection and modification of the design. Therefore this research shows that tangible user interfaces changes designers' spatial cognition, and the changes of the spatial cognition are associated with creative design processes.     

Combining social media affordances for organising collective action

Social media provide new opportunities for supporting the dynamics of collective action (CA), allowing for the mobilisation of people into debates and involving them in new forms of collective decision making. Although current studies focus on opportunities offered by social media for collective action, there is still a need to deepen the understanding of how social media support the organisation of CA and to study the effects of individual actions performed on social media in complex organisational settings. We here explore how social media are used to manage CA by the Italian political movement Movimento Cinque Stelle, using the concept of affordances as the conceptual framing. Based on the qualitative case analyses, our study contributes to the knowledge base by identifying a typology of nine affordances supporting CA and exploring how the combined actualisations of some affordances of the typology create antecedents of the fundamental processes of CA. On the basis of the study analysis, we suggest a model to describe how social media support CA through affordances, their combinations, and the creation of antecedents and then formulate implications for research and practice.     

Web designers and web users: Influence of the ergonomic quality of the web site on the information search

Despite rapid growth in the number of web sites, there is still a significant number of ergonomic problems which hinder web users. Many studies focus on analysing cognitive processes and difficulties experienced by web users, but very few are interested in web designers’ difficulties or in comparing their respective activities. Towards this end, the two experimental studies presented in this article compare the strategies developed both by professional web designers and (novice vs. experienced) web users while searching for information on web sites of varying ergonomic quality. More precisely, we investigated whether web designers can effectively use their own strategies as web users when designing web sites. We presented a comparison of novice web users, experienced web users and professional web designers searching behavior and cognitive load when using ergonomic and non-ergonomic web sites. In addition, we asked web designers to predict the strategy used by novice web users. Based on the results obtained in the two experiments, we conclude that web designers are not able to predict strategies of novice users and do not behave like novice users. Consequently, ways for supporting web designers in developing a user-centered activity are necessary, and certain ways are suggested at the end of this article.     

Perceptual foundations in the design of visual displays

This paper discusses how perception affects the relationship between screen design and memory and cognition. The effects of visual grouping, location of material, distinctiveness of elements and arrangement in layouts, and motion are discussed and analyzed. The perceptual and cognitive principles explored can be applied to the design of any visual display. This information provides designers with a perceptual framework for maximizing learning conditions.     

分布式多计算机系统中的存储扩充问题及其解决办法

在大规模分布式多计算机系统中,内外存之间容量的差距正在减小,这极大地影响了操作系统中存储管理的设计和实现。操作系统设计得必须解决在外存存量不足的情况下如何实施存储扩充。提出了指令对文件直接寻址的概念及其实现方法,并分析了指令对文件直接寻址如何解决了这个问题。     

A Design Thinking Rationality Framework: Framing and Solving Design Problems in Early Concept Generation

The concept of “Design Thinking” opens up debate regarding the prevalent human–computer interaction design practice. This article focuses specifically on the cognitive processes of designers during their early design activities. Two groups of designers—experts and novices—were asked to develop a fictitious vacuum cleaner. We then examined the different ways in which these groups manage their design thinking processes and how the groups choose design concepts. The empirical study revealed that expert designers are effective at framing design problems. They make quick decisions (through the use of the affect heuristic) but are more wedded to their own previously developed design concepts, which they do not change in subsequent design stages. In contrast, novice designers are less skilled in framing new design problems but better able to renounce their initial design concepts. These diverse design thinking approaches are linked to potential problems. We then discuss how to address these concerns in conjunction with empathy for the artifact (i.e., artifact empathy via the mediated self) or user (i.e., user empathy via the simulated self), problem framing with second-order semantic connotations, and irrationality when analyzing design solutions. Finally, we propose a design thinking rationality framework that can establish a designer's view of design activities and thereby assist designers educated in both creative and rational design decisions.     

Looking for powerful abstractions [object oriented technology]

In this paper the author explores the ways that have helped him to become a better designer. Designers must be able to see the problem out there in the real world and solve it by applying the right tools and technologies. Like artists, object designers need to see in special ways to create good solutions - call this modeling or designing. Object technology is just one tool in a very rich toolbox and author discusses the fundamental design skill of finding objects. Finding the right level of abstraction takes practice and experimentation. There are times when both concrete classes and their common abstraction add value to a design, and there are times when they don't. To find good classes, experienced designers make distinctions based on significant behavior differences.     

Comprehending product warning information: age-related effects and the roles of memory, inferencing, and knowledge

Two experiments were conducted to determine if age affects comprehension for explicit and implied warning information and, if so, to reveal the nature of such effects. Experiment 1 measured younger (18-23 years) and older (65-75 years) adults' comprehension for real-world warnings via a verification test presented immediately after reading the warnings or after a delay. In Experiment 2, younger (18-22 years) and older (64-76 years) participants also read fabricated warnings that were inconsistent with real-world knowledge. In both experiments, older adults frequently failed to infer the correct hazard and safety information. The older adults also had trouble understanding warning information even when it was explicitly stated (when no inferences were required), especially when memory demands were high and product-specific knowledge could not be used. That many of the older adults did not understand commonly used product warnings indicates that the wording on many household products is not conducive to being understood by everyone who uses them. Actual or potential applications of this research include the recommendation that designers of product labels, warnings, and instructions should consider minimizing memory load and maximizing opportunities for knowledge application when designing consumer warnings.     

Affordances in the design of enactive systems

Enactive interfaces must incorporate intuitive activity that characterizes naturalistic perception. However, the manner in which information is presented is not more important than the contents: what information is presented. In this contribution, we address the contents of perception. We argue that people perceive affordances, that is, the possible actions that are available in any given situation. We further argue that enactive interfaces should be designed to optimize presentation of information about the possible actions that are available to a person using the enactive interface. The design of enactive interfaces might be guided by an extension of the theory of ecological interface design (Vicente in Hum Factors 44:62–78, 2002) to include multimodal information that is accessed through fast, intuitive exploratory movement. We review two empirical studies that illustrate our arguments. Careful analysis of affordances, together with our increasing understanding of the enactive perception of affordances, should influence the design of enactive interfaces.     

Using Task-Induced Pupil Diameter and Blink Rate to Infer Cognitive Load

Minimizing user cognitive load is suggested as an integral part of human-centered design, where a more intuitive, easy to learn, and adaptive interface is desired. In this context, it is difficult to develop optimal strategies to improve the design without first knowing how user cognitive load fluctuates during interaction. In this study, we investigate how cognitive load measurement is affected by different task types from the perspective of the load theory of attention, using pupil diameter and blink measures. We induced five levels of cognitive load during low and high perceptual load tasks and found that although pupil diameter showed significant effects on cognitive load when the perceptual load was low, neither blink rate nor pupil diameter showed significant effects on cognitive load when the perceptual load was high. The results indicate that pupil diameter can index cognitive load only in the situation of low perceptual load and are the first to provide empirical support for the cognitive control aspect of the load theory of attention, in the context of cognitive load measurement. Meanwhile, blink is a better indicator of perceptual load than cognitive load. This study also implies that perceptual load should be considered in cognitive load measurement using pupil diameter and blink measures. Automatic detection of the type and level of load in this manner helps pave the way for better reasoning about user internal processes for human-centered interface design.     

Tracking in object action space

In this paper we focus on the joint problem of tracking humans and recognizing human action in scenarios such as a kitchen scenario or a scenario where a robot cooperates with a human, e.g., for a manufacturing task. In these scenarios, the human directly interacts with objects physically by using/manipulating them or by, e.g., pointing at them such as in “Give me that…”. To recognize these types of human actions is difficult because (a) they ought to be recognized independent of scene parameters such as viewing direction and (b) the actions are parametric, where the parameters are either object-dependent or as, e.g., in the case of a pointing direction convey important information. One common way to achieve recognition is by using 3D human body tracking followed by action recognition based on the captured tracking data. For the kind of scenarios considered here we would like to argue that 3D body tracking and action recognition should be seen as an intertwined problem that is primed by the objects on which the actions are applied. In this paper, we are looking at human body tracking and action recognition from a object-driven perspective. Instead of the space of human body poses we consider the space of the object affordances, i.e., the space of possible actions that are applied on a given object. This way, 3D body tracking reduces to action tracking in the object (and context) primed parameter space of the object affordances. This reduces the high-dimensional joint-space to a low-dimensional action space. In our approach, we use parametric hidden Markov models to represent parametric movements; particle filtering is used to track in the space of action parameters. We demonstrate its effectiveness on synthetic and on real image sequences using human-upper body single arm actions that involve objects.     

Observing Human-Object Interactions: Using Spatial and Functional Compatibility for Recognition

Interpretation of images and videos containing humans interacting with different objects is a daunting task. It involves understanding scene/event, analyzing human movements, recognizing manipulable objects, and observing the effect of the human movement on those objects. While each of these perceptual tasks can be conducted independently, recognition rate improves when interactions between them are considered. Motivated by psychological studies of human perception, we present a Bayesian approach which integrates various perceptual tasks involved in understanding human-object interactions. Previous approaches to object and action recognition rely on static shape/appearance feature matching and motion analysis, respectively. Our approach goes beyond these traditional approaches and applies spatial and functional constraints on each of the perceptual elements for coherent semantic interpretation. Such constraints allow us to recognize objects and actions when the appearances are not discriminative enough. We also demonstrate the use of such constraints in recognition of actions from static images without using any motion information.