Explicating Affordances: A Conceptual Framework for Understanding Affordances in Communication Research

This study aims to clarify inconsistencies regarding the term affordances by examining how affordances terminology is used in empirical research on communication and technology. Through an analysis of 82 communication‐oriented scholarly works on affordances, we identify 3 inconsistencies regarding the use of this term. First, much research describes a particular affordance without engaging other scholarship addressing that affordance. Second, several studies identify “lists” of affordances without conceptually developing individual affordances within those lists. Third, the affordances perspective is evoked in situations where the purported affordance does not meet commonly accepted definitions. We conclude with a set of criteria to aid scholars in evaluating their assumptions about affordances and to facilitate a more consistent approach to its conceptualization and application.     

Afforded actions as a behavioral assessment of physical presence in virtual environments

A particular affordance was used as a potential candidate for behavioral assessment of physical presence in virtual environments. The subjects’ task was to walk through a virtual aperture of variable widths. In the case of presence, the subjects’ body orientation, while walking, was hypothesized to be adapted to the width of the aperture and to their own shoulder width. Results show that most subjects adapted their behavior to both their body architecture and the virtual width constraints. These subjects exhibited a behavioral transition from frontal walking to body rotation while walking through broad to narrow apertures. The same behavioral transition has already been documented in real environments (Warren and Whang in J Exp Psychol Human Percept Perform 13(3):371–383, 1987). This behavioral adjustment is thus assumed to be an objective indication of presence. Beyond these results, the present study suggests that every afforded action could be a potential tool for sensorimotor assessment of physical presence. Parts of this research have been first presented at the 11th Annual International Workshop of Presence, Padova, Italy, 16-18 October 2008.     

In-car speed estimations with real,virtual, and no view

Car handling, and hence, safety, is affected by the way we estimate speed. Speed, however, is often underestimated in degraded visual environments, including virtual environments such as driving simulators. In simulators the visual and physical motion are typically incongruent as limited by quality and amplitude, respectively, which may cause a negative transfer of training. To improve the (training) quality of simulators and make them feel more real, it would be helpful to fill a knowledge gap on in-car speed perception as affected by real and virtual views, within a single group of subjects. We did so by testing whether estimations of speed in terms of km/h could be a valid metric for that purpose.We therefore exposed 17 subjects, seated as passengers in the front of a car on a straight road to four experimental conditions: (1) driving with a real out-the-window view, (2) driving with a live video view, (3) standing still watching pre-recorded video's, and (4) driving with eyes closed. Field-of-view was made equal in all conditions. Speeds tested ranged between 20 and 60 km/h.On average, speed was estimated 5 km/h less than actual, while we did not find a statistically significant difference between the four conditions tested.These results seem to contradict previous observations on motion perception, in particular in simulators, that have been ascribed to the quality of the visuals used. This finding may yet be explained by the assumption that speed estimations in terms of km/h are dominated by (conscious) cognitive processes, while visual-vestibular coherence between visual and physical motion, is dominated by (unconscious) sensorial driven perceptual processes. This disqualifies perceived speed as a valid metric for studying motion perception related to the optimisation of simulators.     

Trajectory of Affordances: Insights from a case of telemedicine in Nepal

Although Affordance Theory has become increasingly influential in the Information Systems (IS) literature, the exact process through which the affordances of IT are actualised is less studied. In this paper, we build on a realist ontology of affordance and an interpretive epistemology of how affordances are perceived and actualised to trace the process of actualisation. On the basis of insights drawn from a case study of a telemedicine project in a remote mountainous region of Nepal, we develop a concept, which we call the “Trajectory of Affordances.” Trajectory of Affordances captures the complex relations between affordances of IT and the role of goal‐oriented actors who perceive and then play a vital role in actualising them, using capabilities that are enabled by facilitating conditions to take the necessary action. Trajectory of Affordances shows that the affordances of IT can travel from perception to actualisation through multiple paths, sometimes clustering together, and in the process, often lead to the emergence of new affordances.     

BiOSS: A system for biomedical ontology selection

In biomedical informatics, ontologies are considered a key technology for annotating, retrieving and sharing the huge volume of publicly available data. Due to the increasing amount, complexity and variety of existing biomedical ontologies, choosing the ones to be used in a semantic annotation problem or to design a specific application is a difficult task. As a consequence, the design of approaches and tools addressed to facilitate the selection of biomedical ontologies is becoming a priority. In this paper we present BiOSS, a novel system for the selection of biomedical ontologies. BiOSS evaluates the adequacy of an ontology to a given domain according to three different criteria: (1) the extent to which the ontology covers the domain; (2) the semantic richness of the ontology in the domain; (3) the popularity of the ontology in the biomedical community. BiOSS has been applied to 5 representative problems of ontology selection. It also has been compared to existing methods and tools. Results are promising and show the usefulness of BiOSS to solve real-world ontology selection problems. BiOSS is openly available both as a web tool and a web service.     

Evaluating ontologies: Towards a cognitive measure of quality

Ontologies are formal specifications of shared conceptualizations of a domain. Important applications of ontologies include distributed knowledge-based systems, such as the semantic web, and the evaluation of modelling languages, e.g. for business process or conceptual modelling. These applications require formal ontologies of good quality. The quality of a formal ontology requires both a good conceptualization of a domain and a good specification of the conceptualization. In this paper, we focus on the latter aspect, and present a method to test how well a specification of a formal ontology corresponds to a conceptualization of a domain held by ontology users. Our experimental method is based on principles of cognitive psychology. We present two experiments to demonstrate our method using upper-level ontologies.     

Perception and biomechanics data in a manual handling task: a comparative study

This paper explores the use of subjective perception tasks and its correlations with biomechanical data in the evaluation of manual material handling. Three main dimensions were considered for perception: physical regroups sensations issued from a specific body area; operative regroups feelings related to the execution of the task; and performance regroups feelings that involve a judgement on the execution or reflect overall sensations. The following questions were then explored. To what extent are perception data related to biomechanics data? Do both approaches lead to similar conclusions or interpretations when effect of practice, format and off-centre were tested? How can they complement one another? The task consisted of transferring 50 series of three 15 kg loads in order to verify the impact of free practice, format (box/cylinder) and load centre of gravity position. Eleven subjects rated perception on a CR-10 scale (Borg 1982 Borg, G. A.V. 1982. Psychophysical bases of perceived exertion. Medicine and Science in Sports and Exercise, 14: 377–381. [Crossref], [PubMed], [Web of Science ®] , [Google Scholar]) after each series. The session was completed with an interview on perception. The net resulting moment was systematically found to be the best correlated with data perception. While all physical and performance items corresponded in various ways to biomechanics data, perceptions associated with operative dimension appeared to be less related with biomechanical data. As regards the impact of practice, format and off-centre, both approaches would lead to the same conclusions, except for the effect of the off-centre. Verbal data add rational information about how or why perception can or cannot be reflected in biomechanics data. How both approaches can be matched more closely in manual handling is discussed.     

Lab-on-a-chip: a component view

Miniaturization is being increasingly applied to biological and chemical analysis processes. Lab-on-a-chip systems are direct creation of the advancement in the miniaturization of these processes. They offer a host of exciting applications in several areas including clinical diagnostics, food and environmental analysis, and drug discovery and delivery studies. This paper reviews lab-on-a-chip systems from their components perspective. It provides a categorization of the standard functional components found in lab-on-a-chip devices together with an overview of the latest trends and developments related to lab-on-a-chip technologies and their application in nanobiotechnology. The functional components include: injector, transporter, preparator, mixer, reactor, separator, detector, controller, and power supply. The components are represented by appropriate symbols allowing designers to present their lab-on-a-chip products in a standard manner. Definition and role of each functional component are included and complemented with examples of existing work. Through the approach presented in this paper, it is hoped that modularity and technology transfer in lab-on-a-chip systems can be further facilitated and their application in nanobiotechnology be expanded     

An app a day keeps a customer connected: Explicating loyalty to brands and branded applications through the lens of affordance and service-dominant logic

The rise of mobile apps is compelling ambitious companies to rush to market their own branded apps in hopes of building customers’ brand loyalty. By applying service-dominant logic, the lens of affordance, and two brand perceptions (brand competence and brand warmth), this study explores critical determinants of app continuance intention and brand loyalty among app users. Five affordances of branded apps are linked to value-in-use, which contributes both directly and indirectly to the two loyalty-related outcomes, through either brand competence or brand warmth. Data collected from 634 app users support all proposed hypotheses. Theoretical and practical implications are discussed.     

Ontology learning: state of the art and open issues

Ontology is one of the fundamental cornerstones of the semantic Web. The pervasive use of ontologies in information sharing and knowledge management calls for efficient and effective approaches to ontology development. Ontology learning, which seeks to discover ontological knowledge from various forms of data automatically or semi-automatically, can overcome the bottleneck of ontology acquisition in ontology development. Despite the significant progress in ontology learning research over the past decade, there remain a number of open problems in this field. This paper provides a comprehensive review and discussion of major issues, challenges, and opportunities in ontology learning. We propose a new learning-oriented model for ontology development and a framework for ontology learning. Moreover, we identify and discuss important dimensions for classifying ontology learning approaches and techniques. In light of the impact of domain on choosing ontology learning approaches, we summarize domain characteristics that can facilitate future ontology learning effort. The paper offers a road map and a variety of insights about this fast-growing field.     

CroMatcher: An ontology matching system based on automated weighted aggregation and iterative final alignment

In order to perform ontology matching with high accuracy, while at the same time retaining applicability to most diverse input ontologies, the matching process generally incorporates multiple methods. Each of these methods is aimed at a particular ontology component, such as annotations, structure, properties or instances. Adequately combining these methods is one of the greatest challenges in designing an ontology matching system. In a parallel composition of basic matchers, the ability to dynamically set the weights of the basic matchers in the final output, thus making the weights optimal for the given input, is the key breakthrough for obtaining first-rate matching performance. In this paper we present CroMatcher, an ontology matching system, introducing several novelties to the automated weight calculation process. We apply substitute values for matchers that are inapplicable for the particular case and use thresholds to eliminate low-probability alignment candidates. We compare the alignments produced by the matchers and give less weight to the matchers producing mutually similar alignments, whereas more weight is given to those matchers whose alignment is distinct and rather unique. We also present a new, iterative method for producing one-to-one final alignment of ontology structures, which is a significant enhancement of similar non-iterative methods proposed in the literature. CroMatcher has been evaluated against other state-of-the-art matching systems at the OAEI evaluation contest. In a large number of test cases it achieved the highest score, which puts it among the state-of-the-art leaders.     

Graph separators: a parameterized view

Graph separation is a well-known tool to make (hard) graph problems accessible to a divide-and-conquer approach. We show how to use graph separator theorems in combination with (linear) problem kernels in order to develop fixed parameter algorithms for many well-known NP-hard (planar) graph problems. We coin the key notion of glueable select&verify graph problems and derive from that a prospective way to easily check whether a planar graph problem will allow for a fixed parameter algorithm of running time for constant c. One of the main contributions of the paper is to exactly compute the base c of the exponential term and its dependence on the various parameters specified by the employed separator theorem and the underlying graph problem. We discuss several strategies to improve on the involved constant c.     

流程可定制本体匹配框架:RiMOM2

本体作为语义Web中的语义表示形式,是语义Web体系结构中的核心元素,是实现知识共享、协同工作的关键。然而现实世界中本体自身与生俱来的分布性和异构性,又极大地限制了数据的共享与集成。为了实现知识的共享、数据的集成,近年来针对本体匹配方法的研究得到了广泛的重视。随着本体匹配研究的深入,许多有效的本体匹配方法被提出。RiMOM2正是一种集成了多种有效本体匹配方法的多策略本体匹配框架。它尽可能地向初级用户隐藏不必要的阂值设定和参数设置,而向高级用户提供匹配流程的可定制功能,以期针对不同用户实现一种既能适用于普遍本体匹配任务,操作简易,又能达到具有针对性匹配效果的本体匹配工具。同时该框架具有匹配方法组件的易扩展性。     

Articulating User Needs in Collaborative Design: Towards an Activity-Theoretical Approach

This paper analyses the collaborative design ofa high-technology product, a neuromagnetometerused in the analysis of the activity of thehuman cortex. The producer, Neuromag Company istrying to transform the device from a basicresearch instrument into a means of clinicalpractice. This transition is analyzed as asimultaneous evolution of the product,producer-user network and user activities. Thenetwork is analyzed as a network of activitysystems. Each activity has a historicallyformed object and a motive of its own, as wellas a system of cultural means and expertise. Weuse these to explain and understand theinterests and points of view of the actors inrelation to the product and the contradictionsof the producer-user network. It is suggestedthat the emerging user needs of collectiveactors must be analyzed at three levels. At thefirst level, the use value of the product, itscapacity of solving the vital problems andchallenges of developing user activities, ischaracterized. The second-level analysisconcerns the creation and development of thenecessary complementary tools and services thatmake the implementation and use of the productpossible. This task presupposes collaborationbetween several communities of the innovationnetwork. The third level is the situatedpractical use of the product. In ourexperience, it is advantageous that researcherscontribute with their data to a dialogue inwhich the user needs are articulated.     

Action research and knowledge co-generation: a not so dangerous liaison with conventional social research

The article reflects on experience of action research in the context of regional development, where there has been pressure to produce practical results. The epistemological status of Action Research is explored, in contrast to conventional social science research. The article concludes that an ongoing relationship with conventional social research is necessary.An earlier version of this paper has been presented at the workshop: Innovation and Regional Development Kingston University 10th December 2004     

Adam revisited: a weighted past gradients perspective

Adaptive learning rate methods have been successfully applied in many fields, especially in training deep neural networks. Recent results have shown that adaptive methods with exponential increasing weights on squared past gradients (i.e., ADAM, RMSPROP) may fail to converge to the optimal solution. Though many algorithms, such as AMSGRAD and ADAMNC, have been proposed to fix the non-convergence issues, achieving a data-dependent regret bound similar to or better than ADAGRAD is still a challenge to these methods. In this paper, we propose a novel adaptive method weighted adaptive algorithm (WADA) to tackle the non-convergence issues. Unlike AMSGRAD and ADAMNC, we consider using a milder growing weighting strategy on squared past gradient, in which weights grow linearly. Based on this idea, we propose weighted adaptive gradient method framework (WAGMF) and implement WADA algorithm on this framework. Moreover, we prove that WADA can achieve a weighted data-dependent regret bound, which could be better than the original regret bound of ADAGRAD when the gradients decrease rapidly. This bound may partially explain the good performance of ADAM in practice. Finally, extensive experiments demonstrate the effectiveness of WADA and its variants in comparison with several variants of ADAM on training convex problems and deep neural networks.     

Reusing ontologies on the Semantic Web: A feasibility study

Technologies for the efficient and effective reuse of ontological knowledge are one of the key success factors for the Semantic Web. Putting aside matters of cost or quality, being reusable is an intrinsic property of ontologies, originally conceived of as a means to enable and enhance the interoperability between computing applications. This article gives an account, based on empirical evidence and real-world findings, of the methodologies, methods and tools currently used to perform ontology-reuse processes. We study the most prominent case studies on ontology reuse, published in the knowledge-/ontology-engineering literature from the early nineties. This overview is complemented by two self-conducted case studies in the areas of eHealth and eRecruitment in which we developed Semantic Web ontologies for different scopes and purposes by resorting to existing ontological knowledge on the Web. Based on the analysis of the case studies, we are able to identify a series of research and development challenges which should be addressed to ensure reuse becomes a feasible alternative to other ontology-engineering strategies such as development from scratch. In particular, we emphasize the need for a context- and task-sensitive treatment of ontologies, both from an engineering and a usage perspective, and identify the typical phases of reuse processes which could profit considerably from such an approach. Further on, we argue for the need for ontology-reuse methodologies which optimally exploit human and computational intelligence to effectively operationalize reuse processes.     

Touching annotations: A visual metaphor for navigation of annotation in digital documents

Direct touch manipulation interactions with technology are now commonplace and significant interest is building around their use in the culture and heritage domain. Such interactions can give people the opportunity to explore materials and artefacts in ways that would otherwise be unavailable. These are often heavily annotated and can be linked to a large array of related digital content, thus enriching the experience for the user. Research has addressed issues of how to present digital documents and their related annotations but at present it is unclear what the optimal interaction approach to navigating these annotations in a touch display context might be.In this paper we investigate the role of two alternative approaches to support the navigation of annotations in digitised documents in the context of a touch interface. Through a control study we demonstrate that, whilst the navigation paradigm displays a significant interaction with the type of annotations task performed, there is no discernible advantage of using a natural visual metaphor for annotation in this context. This suggests that design of digital document annotation navigation tools should account for the context and navigation tasks being considered.