Vagueness: where degree-based approaches are useful, and where we can do without

The vagueness of a property becomes apparent when more than one level of granularity is addressed in a discourse. For instance, the adjective “tall” can be used to distinguish just two kinds of persons—those who are tall as opposed to those who are not. This coarse distinction contrasts with any finer one, in particular with the finest possible one, on which we specify sizes, beyond all limits of precision, by real numbers. We understand vagueness as a relative notion, causing a problem when information on a coarse level is to be transferred to a fine level. Under this viewpoint there is no problem to accept that, depending on the application, reasoning under vagueness may require different formal frameworks. In this paper, we consider the same kind of vague properties in two different contexts. We first discuss a version of the sorites paradox. In this case, it is necessary to combine reasoning on two levels of granularity in a single formalism. Following established practice, we choose an approach based on numerical degrees. Second, we consider generalised Aristotelian syllogisms. In this case, degree-based solutions are unnecessarily rich in structure and are not found adequate. We give preference to a formalism that stays entirely on the coarse level of argumentation. We conclude that there is no reason to call for a uniform formalism to cope with the problem of vagueness. In particular, degree-based approaches are usually applicable, but there can be simpler alternatives. Different problems may call for different solutions, and choosing diversity does not mean that we approach the problem of vagueness incoherently.     

Barriers common to mobile and disabled web users

World Wide Web accessibility and best practice audits and evaluations are becoming increasingly complicated, time consuming, and costly because of the increasing number of conformance criteria which need to be tested. In the case of web access by disabled users and mobile users, a number of commonalities have been identified in usage, which have been termed situationally-induced impairments; in effect the barriers experienced by mobile web users have been likened to those of visually disabled and motor impaired users. In this case, we became interested in understanding if it was possible to evaluate the problems of mobile web users in terms of the aggregation of barriers-to-access experienced by disabled users; and in this way attempt to reduce the need for the evaluation of the additional conformance criteria associated with mobile web best practice guidelines. We used the Barrier Walkthrough (BW) method as our analytical framework. Capable of being used to evaluate accessibility in both the disabled and mobile contexts, the BW method would also enable testing and aggregation of barriers across our target user groups.We tested 61 barriers across four user groups each over four pages with 19 experts and 57 non-experts focusing on the validity and reliability of our results. We found that 58% of the barrier types that were correctly found were identified as common between mobile and disabled users. Further, if our aggregated barriers alone were used to test for mobile conformance only four barrier types would be missed. Our results also showed that mobile users and low vision users have the most common barrier types, while low vision and motor impaired users experiencing similar rates of severity in the barriers they experienced. We conclude that the aggregated evaluation results for blind, low vision and motor impaired users can be used to approximate the evaluation results for mobile web users.     

Improving deaf users' accessibility in hypertext information retrieval: are graphical interfaces useful for them?

This paper explores the effect of substituting textual links for graphical ones on the performance of deaf signers in hypertext information retrieval (HIR). Both deaf and hearing users found more targets, were faster and became less disoriented in the verbal hypertext interface than in the graphical one. Deaf users were outperformed by hearing users in all conditions except in short paths with the graphical interface. The results and its applied consequences, which would be also relevant to other users with similar problems than those of deaf signers (elderly people, people with dyslexia, people navigating in a website using a foreign language or people with low literacy) are discussed in relation to the CoLiDeS model of web interaction (Kitajima et al. 2000) and to the overgeneralisation of 'Picture superiority effect' (Nelson et al. 1976).     

Assessing information quality of e-learning systems: a web mining approach

E-learning systems provide a promising solution as an information exchanging channel. Improved technologies could mean faster and easier access to information but do not necessarily ensure the quality of this information; for this reason it is essential to develop valid and reliable methods of quality measurement and carry out careful information quality evaluations. This paper proposes an assessment model for information quality in e-learning systems based on the quality framework we proposed previously: the proposed framework consists of 14 quality dimensions grouped in three quality factors: intrinsic, contextual representation and accessibility. We use the relative importance as a parameter in a linear equation for the measurement scheme. Formerly, we implemented a goal-question-metrics approach to develop a set of quality metrics for the identified quality attributes within the proposed framework. In this paper, the proposed metrics were computed to produce a numerical rating indicating the overall information quality published in a particular e-learning system. The data collection and evaluation processes were automated using a web data extraction technique and results on a case study are discussed. This assessment model could be useful to e-learning systems designers, providers and users as it provides a comprehensive indication of the quality of information in such systems.     

Automatic cleaning and segmentation of web images based on colors to build learning databases

This article proposes a method to segment Internet images, that is, a group of images corresponding to a specific object (the query) containing a significant amount of irrelevant images. The segmentation algorithm we propose is a combination of two distinct methods based on color. The first one considers all images to classify pixels into two sets: object pixels and background pixels. The second method segments images individually by trying to find a central object. The final segmentation is obtained by intersecting the results from both. The segmentation results are then used to re-rank images and display a clean set of images illustrating the query. The algorithm is tested on various queries for animals, natural and man-made objects, and results are discussed, showing that the obtained segmentation results are suitable for object learning.     

Website accessibility: a survey of local e-government websites and legislation in Northern Ireland

The provision of accessible websites is a legal requirement under the Disability Discrimination Act 1995, which applies throughout Great Britain and Northern Ireland, and the Equality (disability, etc.) (Northern Ireland) Order 2000. A survey of local e-government websites indicated that few local councils in the devolved administration of Northern Ireland offered websites which were adequately usable by people with a disability, yet most citizen-government transactions occur at the local level. Design for all has obvious commercial benefits, but it has also become a legal obligation, and application of accessible design principles should improve the online experience of all users.     

Displaced and dismayed: how ICTs are helping refugees and migrants,and how we can do better

ABSTRACT

Employing ICT platforms has the potential to improve efforts to assist displaced people, or to liberate them in being more able to help each other, or both. And while platform development has resulted in a patchwork of initiatives – an electronic version of ‘letting a thousand flowers bloom’ – there are patterns emerging as to which flowers grow and have ‘staying power’ as compared to ones that wilt and die. Using a partial application of grounded theory, we analyze 47 platforms, categorizing the services they provide, the functionalities they use, and the extent to which end users are involved in initial design and ongoing modification. We found that 23% offer one-way communication, 72%, provide two-way communication, 74% involve crowdsourcing and 43% use artificial intelligence. For future developers, we offer a preliminary list of what leads to a successful ICT initiative for refugees and migrants. Finally, we list ethical considerations for all stakeholders.     

Getting it from the Web: why and how online resources are used by independent undergraduate learners

Abstract Undergraduate students access the Internet for a range of purposes, many unrelated to their studies. Increasingly, learners are using the Internet to find information and resources for coursework, whether or not this is promoted or endorsed by their teachers. This article reports an interview study that investigated why and how independent learners use Web‐based resources, exploring not only the academic context of the courses studied, but also any relevant personal, domestic and employment‐related circumstances. Factors were identified, which enhanced or competed with study activities, acting as incentives or disincentives for learners. The findings suggest that it is not technologies per se, but a combination of various contextual factors, that determine students' use of Web resources for learning. Of the academic factors that emerged from the interviews, assessment requirements and pedagogic approach were particularly important.