Geometric sensitivity of patient-specific finite element models of the spine to variability in user-selected anatomical landmarks

Software to create individualised finite element (FE) models of the osseoligamentous spine using pre-operative computed tomography (CT) data-sets for spinal surgery patients has recently been developed. This study presents a geometric sensitivity analysis of this software to assess the effect of intra-observer variability in user-selected anatomical landmarks. User-selected landmarks on the osseous anatomy were defined from CT data-sets for three scoliosis patients and these landmarks were used to reconstruct patient-specific anatomy of the spine and ribcage using parametric descriptions. The intra-observer errors in landmark co-ordinates for these anatomical landmarks were calculated. FE models of the spine and ribcage were created using the reconstructed anatomy for each patient and these models were analysed for a loadcase simulating clinical flexibility assessment. The intra-observer error in the anatomical measurements was low in comparison to the initial dimensions, with the exception of the angular measurements for disc wedge and zygapophyseal joint (z-joint) orientation and disc height. This variability suggested that CT resolution may influence such angular measurements, particularly for small anatomical features, such as the z-joints, and may also affect disc height. The results of the FE analysis showed low variation in the model predictions for spinal curvature with the mean intra-observer variability substantially less than the accepted error in clinical measurement. These findings demonstrate that intra-observer variability in landmark point selection has minimal effect on the subsequent FE predictions for a clinical loadcase.

From impact assessment to user-friendly risk management decision-making

In earlier cultures and societies, hazards and risks to human health were dealt with by methods derived from myth, metaphor and ritual. In modem society however, notions of hazard and risk have been transformed from the level of a folk discourse to that of an expert centred concept (Plough & Krimsky, 1987). With the professionalization of risk and hazard analysis came a preferred framework for decision making based on a range of 'technical' methodologies (Giere, 1991 ). This is especially true for decision processes relating to risk assessment and management, and impact assessment. Such approaches however, often entail narrow technical-based theoretical assumptions about human behaviour and the natural world, and the· methods used. They therefore carry 'in-built' error factors that contribute considerable uncertainty to the results.

Histories of user-generated content : between formal and informal media economies

Debates about user-generated content (UGC) often depend on a contrast with its normative opposite, the professionally produced content that is supported and sustained by commercial media businesses or public organisations. UGC is seen to appear within or in opposition to professional media, often as a disruptive, creative, change-making force. Our suggestion is to position UGC not in opposition to professional or "producer media", or in hybridised forms of subjective combination with it (the so-called "pro-sumer" or "pro-am" system), but in relation to different criteria, namely the formal and informal elements in media industries. In this article, we set out a framework for the comparative and historical analysis of UGC systems and their relations with other formal and informal media activity, illustrated with examples ranging from games to talkback radio. We also consider the policy implications that emerge from a historicised reading of UGC as a recurring dynamic within media industries, rather than a manifestation of consumer agency specific to digital cultures.

Aspect-based model of user experience

Traditional HCI design and evaluation methods merely focus on functional and usability aspects of a product. Although these aspects are important, they do not guarantee product’s success, especially the consumer product. Many consumer products are now part of user’s everyday activities – that support fun, pleasure, entertainment, etc. Secondly, in today’s consumer market many of the products have become similar in terms of their technology, functionality, price and quality. In response, many companies have started designing products with added emotional and experiential values. This has challenged designer’s to explore and visualize directions in product design field that could evoke intended and desired experiences amongst its users. Subjective product qualities such as fun, pleasure, entertainment, etc. are not the part of a product, but they are better thought of as the outcome of user’s interaction with the product...

Measuring Online user engagement : the limitations of Web analytics

The ability to identify and assess user engagement with transmedia productions is vital to the success of individual projects and the sustainability of this mode of media production as a whole. It is essential that industry players have access to tools and methodologies that offer the most complete and accurate picture of how audiences/users engage with their productions and which assets generate the most valuable returns of investment. Drawing upon research conducted with Hoodlum Entertainment, a Brisbane-based transmedia producer, this chapter outlines an initial assessment of the way engagement tends to be understood, why standard web analytics tools are ill-suited to measuring it, how a customised tool could offer solutions, and why this question of measuring engagement is so vital to the future of transmedia as a sustainable industry.

Improvement of a dynamic accumulator at ICICS 07 and its application in multi-user keyword-based retrieval on encrypted data

A dynamic accumulator is an algorithm, which merges a large set of elements into a constant-size value such that for an element accumulated, there is a witness confirming that the element was included into the value, with a property that accumulated elements can be dynamically added and deleted into/from the original set. Recently Wang et al. presented a dynamic accumulator for batch updates at ICICS 2007. However, their construction suffers from two serious problems. We analyze them and propose a way to repair their scheme. We use the accumulator to construct a new scheme for common secure indices with conjunctive keyword-based retrieval.

Effects of intrinsic and extrinsic motivation on user-generated content

User-generated content where content is created and shared among consumers is of key importance to marketers. This study investigates consumer intrinsic and extrinsic motivation to understand why people create user-generated branded video content. Specifically, we examine the role of altruism (individual difference – intrinsic motivation), social benefits (extrinsic reward), and economic incentives (extrinsic reward) on intentions to create user-generated content. Results show that extrinsic rewards (economic incentives) result in more positive intentions to create user-generated content than intrinsic motivations. However, an effect for altruism is also evident revealing that high altruism consumers are more likely to create positive user-generated content. The implication of these findings is that marketers wanting to encourage user-generated content about their brands should target high altruism consumers and offer economic incentives for content creation.

Detection of dynamic primary user with cooperative spectrum sensing

In this paper we demonstrate that existing cooperative spectrum sensing formulated for static primary users cannot accurately detect dynamic primary users regardless of the information fusion method. Performance error occurs as the sensing parameters calculated by the conventional detector result in sensing performance that violates the sensing requirements. Furthermore, the error is accumulated and compounded by the number of cooperating nodes. To address this limitation, we design and implement the duty cycle detection model for the context of cooperative spectrum sensing to accurately calculate the sensing parameters that satisfy the sensing requirements. We show that longer sensing duration is required to compensate for dynamic primary user traffic.

The drive towards user-centred engineering in automotive design

Falling sales in Europe and increasing global competition is forcing automotive manufacturers to develop a customer-based approach to differentiate themselves from the similarly technologically-optimised crowd. In spite of this new approach, automotive firms are still firmly entrenched in their reliance upon technology-driven innovation, to design, develop and manufacture their products, placing customer focus on a downstream sales role. However the time-honoured technology-driven approach to vehicle design and manufacture is coming into question, with the increasing importance of accounting for consumer needs pushing automotive engineers to include the user in their designs. The following paper examines the challenges and opportunities for a single global automotive manufacturer that arise in seeking to adopt a user-centred approach to vehicle design amongst technical employees. As part of an embedded case study, engineers from this manufacturer were interviewed in order to gauge the challenges, barriers and opportunities for the adoption of user-centred design tools within the engineering design process. The analysis of these interviews led to the proposal of the need for a new role within automotive manufacturers, the “designeer”, to bridge the divide between designers and engineers and allow the engineering process to transition from a technology-driven to a user- centred approach.

User-led innovation in call center knowledge work

So called “knowledge work” is seen as integral to post-industrial society and, for some, information and communications technologies (ICTs) are critical enablers of the associated practices. Many still propose the technologically deterministic route of rolling out ICTs and expecting that users will, and indeed can, “download” what they know into a system that can then be used in a number of ways. This approach is usually underpinned by the predominant assumption that the system will be developed by one group (developers) and used by another group (users). In this paper, we report on an exploratory case study of the enactment of ICT supported knowledge work in a human resources contact center which illustrates the negotiable boundary between the developer and user in local level innovation processes. Drawing upon ideas from the social shaping of technology, we examine how discussions regarding producer-user relations in innovation processes require a degree of greater sophistication as we show how users often develop (or produce) technologies and work practices in situ—in this case, to enable knowledge work practices and contribute to the project of constructing the knowledge component of professional identity. Much has been made of contextualizing the user; further work is required to contextualize the developer as a user and understand the social actors in ICT innovation environments who straddle both domains

Secondary user relations in emerging mobile computing environments

Mobile technologies are enabling access to information in diverse environ.ments, and are exposing a wider group of individuals to said technology. Therefore, this paper proposes that a wider view of user relations than is usually considered in information systems research is required. Specifically, we examine the potential effects of emerging mobile technologies on end-­‐user relations with a focus on the ‘secondary user’, those who are not intended to interact directly with the technology but are intended consumers of the technology’s output. For illustration, we draw on a study of a U.K. regional Fire and Rescue Service and deconstruct mobile technology use at Fire Service incidents. Our findings provide insights, which suggest that, because of the nature of mobile technologies and their context of use, secondary user relations in such emerging mobile environments are important and need further exploration.

Using the Event Analysis of Systemic Teamwork (EAST) to explore conflict between different road user groups when making right hand turns at urban intersections

Collisions between different types of road users at intersections form a substantial component of the road toll. This paper presents an analysis of driver, cyclist, motorcyclist and pedestrian behaviour at intersections that involved the application of an integrated suite of ergonomics methods, the Event Analysis of Systemic Teamwork (EAST) framework, to on-road study data. EAST was used to analyse behaviour at three intersections using data derived from an on-road study of driver, cyclist, motorcyclist and pedestrian behaviour. The analysis shows the differences in behaviour and cognition across the different road user groups and pinpoints instances where this may be creating conflicts between different road users. The role of intersection design in creating these differences in behaviour and resulting conflicts is discussed. It is concluded that currently intersections are not designed in a way that supports behaviour across the four forms of road user studied. Interventions designed to improve intersection safety are discussed.

Utilizing voting systems for ranking user tweets

Twitter is a very popular social network website that allows users to publish short posts called tweets. Users in Twitter can follow other users, called followees. A user can see the posts of his followees on his Twitter profile home page. An information overload problem arose, with the increase of the number of followees, related to the number of tweets available in the user page. Twitter, similar to other social network websites, attempts to elevate the tweets the user is expected to be interested in to increase overall user engagement. However, Twitter still uses the chronological order to rank the tweets. The tweets ranking problem was addressed in many current researches. A sub-problem of this problem is to rank the tweets for a single followee. In this paper we represent the tweets using several features and then we propose to use a weighted version of the famous voting system Borda-Count (BC) to combine several ranked lists into one. A gradient descent method and collaborative filtering method are employed to learn the optimal weights. We also employ the Baldwin voting system for blending features (or predictors). Finally we use the greedy feature selection algorithm to select the best combination of features to ensure the best results.

Acceptability-based QoE management for user-centric mobile video delivery : a field study evaluation

Effective Quality of Experience (QoE) management for mobile video delivery – to optimize overall user experience while adapting to heterogeneous use contexts – is still a big challenge to date. This paper proposes a mobile video delivery system to emphasize the use of acceptability as the main indicator of QoE to manage the end-to-end factors in delivering mobile video services. The first contribution is a novel framework for user-centric mobile video system that is based on acceptability-based QoE (A-QoE) prediction models, which were derived from comprehensive subjective studies. The second contribution is results from a field study that evaluates the user experience of the proposed system during realistic usage circumstances, addressing the impacts of perceived video quality, loading speed, interest in content, viewing locations, network bandwidth, display devices, and different video coding approaches, including region-of-interest (ROI) enhancement and center zooming