Comparing Evaluation Methods for Encumbrance and Walking on Interaction with Touchscreen Mobile Devices

In this paper, two walking evaluation methods were compared to evaluate the effects of encumbrance while the preferred walking speed (PWS) is controlled. Users frequently carry cumbersome objects (e.g. shopping bags) and use mobile devices at the same time which can cause interaction difficulties and erroneous input. The two methods used to control the PWS were: walking on a treadmill and walking around a predefined route on the ground while following a pacesetter. The results from our target acquisition experiment showed that for ground walking at 100% of PWS, accuracy dropped to 36% when carrying a bag in the dominant hand while accuracy reduced to 34% for holding a box under the dominant arm. We also discuss the advantages and limitations of each evaluation method when examining encumbrance and suggest treadmill walking is not the most suitable approach to use if walking speed is an important factor in future mobile studies

SemanticLock: An authentication method for mobile devices using semantically-linked images

We introduce SemanticLock, a single factor graphical authentication solution for mobile devices. SemanticLock uses a set of graphical images as password tokens that construct a semantically memorable story representing the user`s password. A familiar and quick action of dragging or dropping the images into their respective positions either in a \textit{continous flow} or in \textit{discrete} movements on the the touchscreen is what is required to use our solution. The authentication strength of the SemanticLock is based on the large number of possible semantic constructs derived from the positioning of the image tokens and the type of images selected. Semantic Lock has a high resistance to smudge attacks and it equally exhibits a higher level of memorability due to its graphical paradigm. In a three weeks user study with 21 participants comparing SemanticLock against other authentication systems, we discovered that SemanticLock outperformed the PIN and matched the PATTERN both on speed, memorability, user acceptance and usability. Furthermore, qualitative test also show that SemanticLock was rated more superior in like-ability. SemanticLock was also evaluated while participants walked unencumbered and walked encumbered carrying "everyday" items to analyze the effects of such activities on its usage

Searching on the Go: The Effects of Fragmented Attention on Mobile Web Search Tasks

Smart phones and tablets are rapidly becoming our main method of accessing information and are frequently used to perform on-the-go search tasks. Mobile devices are commonly used in situations where attention must be divided, such as when walking down a street. Research suggests that this increases cognitive load and, therefore, may have an impact on performance. In this work we conducted a laboratory experiment with both device types in which we simulated everyday, common mobile situations that may cause fragmented attention, impact search performance and affect user perception. Our results showed that the fragmented attention induced by the simulated conditions significantly affected both participants' objective and perceived search performance, as well as how hurried they felt and how engaged they were in the tasks. Furthermore, the type of device used also impacted how users felt about the search tasks, how well they performed and the amount of time they spent engaged in the tasks. These novel insights provide useful information to inform the design of future interfaces for mobile search and give us a greater understanding of how context and device size affect search behaviour and user experience

Searching on the go : the effects of fragmented attention on mobile web search tasks

Smart phones and tablets are rapidly becoming our main method of accessing information and are frequently used to perform on-the-go search tasks. Mobile devices are commonly used in situations where attention must be divided, such as when walking down a street. Research suggests that this increases cognitive load and, therefore, may have an impact on performance. In this work we conducted a laboratory experiment with both device types in which we simulated everyday, common mobile situations that may cause fragmented attention, impact search performance and affect user perception. Our results showed that the fragmented attention induced by the simulated conditions significantly affected both participants' objective and perceived search performance, as well as how hurried they felt and how engaged they were in the tasks. Furthermore, the type of device used also impacted how users felt about the search tasks, how well they performed and the amount of time they spent engaged in the tasks. These novel insights provide useful information to inform the design of future interfaces for mobile search and give us a greater understanding of how context and device size affect search behaviour and user experience

The impact of encumbrance on mobile interactions

Part 1: Long and Short Papers (Continued); International audience; This paper investigates the effects of encumbrance (holding different types of objects while using mobile devices) to understand the interaction difficulties that it causes. An experiment was conducted where participants performed a target acquisition task on a touchscreen mobile phone while carrying different types of bags and boxes. Mobility was also evaluated since people carry items from one place to another. Motion capture hardware was used to track hand and arm postures to examine how holding the different types of objects caused excessive movement and instability therefore resulting in performance to decline. The results showed encumbrance and mobility caused target accuracy to decrease although input while holding the box under the non-dominant arm was more accurate and exerted quicker targeting times than holding no objects. Encumbrance affected the dominant hand more than the non-dominant hand as targeting error significantly increased and caused greater hand instability. The issues caused by encumbrance suggest the topic requires more attention from researchers and users would benefit greatly if better interaction techniques and applications are developed to counteract the problems. Document type: Part of book or chapter of boo

Retracing trajectories: the embodied experience of cycling, urban sensescapes and the commute between ‘neighbourhood’ and ‘city’ in Utrecht, NL

This paper looks into the experience of “passing through different territories of the city” (Sennett, 2006, p. 3). Despite their importance for making sense of the city as a whole, these experiences are often not acknowledged in urban planning. This paper compares the everyday, embodied experiences of commuter cyclists with the planners’ perspective on Utrecht. ‘On the ground’ data was collected via ride-alongs with 15 inhabitants of the Leidsche Rijn neighbourhood. Our analysis reveals cycling trajectories composed of diverse sensescapes. It paints a much more complex picture of intra-urban divisions and connections than the planners’ perspective of the ‘new’ Leidsche Rijn neighbourhood separated from the ‘old’ city by major infrastructure lines

The effects of encumbrance and mobility on interactions with touchscreen mobile devices

Mobile handheld devices such as smartphones are now convenient as they allow users to make calls, reply to emails, find nearby services and many more. The increase in functionality and availability of mobile applications also allow mobile devices to be used in many different everyday situations (for example, while on the move and carrying items). While previous work has investigated the interaction difficulties in walking situations, there is a lack of empirical work in the literature on mobile input when users are physically constrained by other activities. As a result, how users input on touchscreen handheld devices in encumbered and mobile contexts is less well known and deserves more attention to examine the usability issues that are often ignored. This thesis investigates targeting performance on touchscreen mobile phones in one common encumbered situation - when users are carrying everyday objects while on the move. To identify the typical objects held during mobile interactions and define a set of common encumbrance scenarios to evaluate in subsequent user studies, Chapter 3 describes an observational study that examined users in different public locations. The results showed that people carried different types of bags and boxes the most frequently. To measure how much tapping performance on touchscreen mobile phones is affected, Chapter 4 examines a range of encumbrance scenarios, which includes holding a bag in-hand or a box underarm, either on the dominant or non-dominant side, during target selections on a mobile phone. Users are likely to switch to a more effective input posture when encumbered and on the move, so Chapter 5 investigates one- and two- handed encumbered interactions and evaluates situations where both hands are occupied with multiple objects. Touchscreen devices afford various multi-touch input types, so Chapter 6 compares the performance of four main one- and two- finger gesture inputs: tapping, dragging, spreading & pinching and rotating, while walking and encumbered. Several main evaluation approaches have been used in previous walking studies, but more attention is required when the effects of encumbrance is also being examined. Chapter 7 examines the appropriateness of two methods (ground and treadmill walking) for encumbered and walking studies, justifies the need to control walking speed and examines the effects of varying walking speed (i.e. walking slower or faster than normal) on encumbered targeting performance. The studies all showed a reduction in targeting performance when users were walking and encumbered, so Chapter 8 explores two ways to improve target selections. The first approach defines a target size, based on the results collected from earlier studies, to increase tapping accuracy and subsequently, a novel interface arrangement was designed which optimises screen space more effectively. The second approach evaluates a benchmark pointing technique, which has shown to improve the selection of small targets, to see if it is useful in walking and encumbered contexts

Planning for plurality of streets:a spheric approach to micromobilities

Micromobilities have proliferated over recent years, enabled by technological advances. Together they present opportunities to flip urban mobility into a new system, beyond car dominance, towards inclusivity, diversity, and sustainability. We propose a theoretical framework to compare these vehicles and assess their potential in urban space. The notion of Sphere and the conceptions associated with it guide the development of our framework, enabling classification and analysis of micromobilities evaluating their impacts on their immediate environment and their capacities to cohabit with other modes of transport. The discursive analysis of 53 interviewees is used to corroborate our framework, particularly investigating the spheric characteristics of mobility experiences using various modes in diverse urban settings in Switzerland. This paper first adopts a historical perspective, exploring the emergence of vehicular innovations that developed in response to the early problems faced by the car system in cities and traces the evolution of these innovations through to the recent proliferation of micromobilities. Then the framework and interviews are described. Finally, we discuss the socio-spatial implications of the classification of transport modes based on their spheric properties, with a view to enabling new perspectives and potentially new socio-spatial relations towards the plurality of streets