Yeliz Yesilada

Yeliz Yesilada
Middle East Technical University, Northern Cyprus Campus · Computer Engineering

PhD

About

165
Publications
23,172
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Publications

Publications (165)
Article
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 be...
Article
Small devices such as personal digital assistants (PDAs) are widely used to access the World Wide Web (Web). However, accessing the Web from small devices is affected by poor interface bandwidth, such as small keyboards and limited pointing devices. There is little empirical work investigating the input difficulties caused by such insufficient faci...
Article
Conventional thought from the Semantic Web community equates the use of ontologies with the representation of the meaning of content. Here, we skew this viewpoint by describing our ontology, Web Authoring for Accessibility (WAfA), which investigates the way ontologies can describe the semantic structure of documents. By understanding the way hetero...
Article
Previous studies have defined a new type of impairment in which an able-bodied user's behaviour is impaired by both the characteristics of a device and the environment in which it is used. This behavioural change is defined as a situationally-induced impairment and is often associated with small devices used in a mobile setting or constrained envir...
Article
Table mining on the web is an open problem, and none of the previously proposed techniques provides a complete solution. Most research focuses on the structure of the HTML document, but because of the nature and structure of the web, it is still a challenging problem to detect relational tables. Web Content Accessibility Guidelines (WCAG) also cove...
Article
Eye-tracking studies typically collect enormous amount of data encoding rich information about user be5 haviours and characteristics on the web. Eye-tracking data has been proved to be useful for usability and accessibility 6 testing and for developing adaptive systems. The main objective of our work is to mine eye-tracking data with machine 7 lear...
Article
Full-text available
A major limitation of the international well-known standard web accessibility guidelines for people with cognitive disabilities is that they have not been empirically evaluated by using relevant user groups. Instead, they aim to anticipate issues that may arise following the diagnostic criteria. In this paper, we address this problem by empirically...
Article
Eye-tracking research enables us to understand how users interact with visual stimuli. It has widely been used to understand user interaction with web pages for various purposes, such as to assess the usability and accessibility of web pages. However, individual eye movement sequences (i.e. scanpaths) tend to be complicated and differ from each oth...
Article
Understanding visual complexity as it relates to websites has been an emergent area for many years. However, predicting the visual complexity of a website as perceived by users has been a real challenge. Perception is important because it influences user engagement, dictating if they will find it dull, engaging, or too complex. While others have su...
Conference Paper
Eye tracking is a growing field of research that is widely used to understand user behaviours and cognitive strategies. Eye-trackers typically collect an enormous amount of data that needs to be analysed, processed and interpreted to draw some conclusions. Collected data is typically examined with either commonly used statistical tools such as SPSS...
Article
Small screen and wearable devices play a key role in most of our daily tasks and activities. However, depending on the context, users can easily experience situationally induced impairments and disabilities (SIIDs). Previous studies have defined SIIDs as a new type of impairment in which an able-bodied user’s behaviour is impaired by the context in...
Article
The purpose of this study is to test whether visual processing differences between adults with and without highfunctioning autism captured through eye tracking can be used to detect autism. We record the eye movements of adult participants with and without autism while they look for information within web pages. We then use the recorded eye-trackin...
Conference Paper
Autism diagnostic procedure is a subjective, challenging and expensive procedure and relies on behavioral, historical and parental report information. In our previous, we proposed a machine learning classifier to be used as a potential screening tool or used in conjunction with other diagnostic methods, thus aiding established diagnostic methods. T...
Conference Paper
Health conditions, both chronic and acute, are often accompanied by disability-like impairments that might affect mobility, cognition, or perception. These impairments are often pernicious because they are difficult to isolate, vary in intensity and extent over time, and are under-investigated. Here, we make the case that solutions to these impairm...
Article
Web pages are composed of different kinds of elements (menus, adverts, etc.). Segmenting pages into their elements has long been important in understanding how people experience those pages and in making those experiences “better.” Many approaches have been proposed that relate the resultant elements with the underlying source code; however, they d...
Thesis
Eye tracking studies typically collect an enormous amount of data that encodes a lot of information about the users’ behavior and characteristics on the web. However, there are not many studies that mine such data to learn and discover user characteristics and profiles. The main goal of this study is to mine eye tracking data by machine learning me...
Conference Paper
Full-text available
People with autism often exhibit different visual behaviours from neurotypical users. To explore how these differences are exhibited on the Web, we model visual behaviour by combining pupillary response, which is an unobtrusive measure of physiological arousal, with eye-tracking scan paths that indicate visual attention. We evaluated our approach w...
Chapter
Accessibility has, at its heart, the aim of removing developer and content creator preconceptions as to the technology, people, working environment, and use their systems support. The move to mobile has been nothing but positive for the accessibility of people with a visual disability. Similarly in the next 10 years as the Web becomes a utility, im...
Article
Full-text available
Ensuring web accessibility for all is not an easy task and requires the awareness, understanding and practices of people with different roles. User experience professionals (UXPs) play an important role in ensuring web accessibility for all. However, in Turkey, there is no research concerning the status of the awareness, understanding and common pr...
Conference Paper
Anecdotal evidence suggests there is a disjoint between the interaction experiences of sighted and visually disabled web users. However, we propose the converse and suggest that this disjoint is created by the lack of understanding of the interplay between the two domains. Current research shows that there is one single locus of attention at a give...
Conference Paper
To accommodate the needs of web users with high-functioning autism, a designer's only option at present is to rely on guidelines that: i) have not been empirically evaluated and ii) do not account for the different levels of autism severity. Before designing effective interventions, we need to obtain an empirical understanding of the aspects that s...
Article
Unobtrusive activity recognition is known to be the most preferred solution for monitoring daily activities of elderly people. In this paper, Scanpath Trend Analysis (STA) is employed for unobtrusive activity recognition of elderly people living alone. Binary sensor data is used and each activity is considered as a sequence of sensor points for thi...
Conference Paper
Full-text available
Situationally-induced impairments and disabilities (SIIDs) make it difficult for users of interactive computing systems to perform tasks due to context (e.g., listening to a phone call when in a noisy crowd) rather than a result of a congenital or acquired impairment (e.g., hearing damage). SIIDs are a great concern when considering the ubiquitousn...
Preprint
When we interact with small screen devices, sometimes we make errors, due to our abilities/disabilities, contextual factors that distract our attention or problems related to the interface. Recovering from these errors may be time consuming or cause frustration. Predicting and learning these errors based on the previous user interaction and context...
Preprint
Full-text available
The workshop paper can be downloaded from here https://dl.acm.org/citation.cfm?id=3299029 and the proceedings for the workshop can be found here https://arxiv.org/html/1904.05382
Article
Anecdotal evidence suggests that people with autism may have different processing strategies when accessing the web. However, limited empirical evidence is available to support this. This paper presents an eye tracking study with 18 participants with high-functioning autism and 18 neurotypical participants to investigate the similarities and differ...
Conference Paper
Full-text available
Eye tracking studies are increasingly used for understanding how people interact with web pages. However, these studies are typically costly and time-consuming. Some of the main reasons are the difficulty in finding participants, the cost of equipment and the need for a separate session for each participant. Due to these reasons, eye tracking studi...
Conference Paper
Full-text available
Understanding what role a visual element plays in a web page can have a significant impact in the accessibility of that page. From an accessibility conformance testing perspective, several WCAG techniques require role identification of some visual elements during the testing process. This has prevented automatic accessibility evaluation tools from...
Conference Paper
Full-text available
The ASD diagnosis requires a long, elaborate, and expensive procedure, which is subjective and is currently restricted to behavioural, historical, and parent-report information. In this paper, we present an alternative way for detecting the condition based on the atypical visual-attention patterns of people with autism. We collect gaze data from tw...
Article
Full-text available
User studies are typically difficult, recruiting enough users is often problematic and each experiment takes a considerable amount of time to be completed. In these studies, eye tracking is increasingly used which often increases time, therefore, the lower the number of users required for these studies the better for making these kinds of studies m...
Conference Paper
Web pages are usually designed for visual interaction and typically supported with visual blocks on web pages. For instance, menu, header, main content and footer are used as the main visual blocks of web pages. These visual elements are separated with spaces which are used as way-edges. For example, the space between the menu and main content is a...
Article
Web pages typically include many visual elements such as header and footer to support interaction with the user. However, if web pages do not comply with web accessibility guidelines, and these visual elements are not explicitly encoded in the underlying source code, they become inaccessible in alternative presentations, such as audio. This article...
Conference Paper
Mobile devices and also the web have become essential in our daily lives. Although mobile devices nowadays are technically much stronger than the desktops in the past, they still have some limitations regarding the battery size, processing power, and device memory. Additionally , the development of battery capacity is slow and increasing at around...
Conference Paper
Web-based interactive systems can be verified and validated with eye tracking which provides valuable insights for understanding user interactions. However, individual eye movements (scanpaths) tend to be complicated and different from each other. Existing algorithms focus on clustering multiple scanpaths into a single representative path, but do n...
Conference Paper
Battery capacity (energy density) is increasing at around 3% per year. However, the increasing requirements of the mobile platform is placing higher demands on this capacity. In this case, there are three options: decrease our expectations of the mobile platform, increase the capacity and therefore size and weight of our batteries, or create energy...
Conference Paper
Elements related to cognitive disability are given lower priority in web accessibility guidelines due to limited understanding of the requirements of neurodiverse web users. Meanwhile, eye tracking has received a lot of interest in the accessibility community as a way to understand user behaviours. In this study, we combine results from information...
Article
Full-text available
We present an experiment comparing performance of 20 novice evaluators of accessibility carrying out Web Content Accessibility Guidelines 2.0 conformance reviews working individually to performance obtained when they work in teams of two. They were asked to first carry out an individual assessment of a web page. Later on, they were matched randomly...
Article
Eye tracking studies have widely been used in improving the design and usability of web pages and in the research of understanding how users navigate them. However, there is limited research in clustering users’ eye movement sequences (i.e., scanpaths) on web pages to identify a general direction they follow. Existing research tends to be reduction...
Conference Paper
Eye tracking has been widely used to investigate user interactions with the Web to improve user experience. In our previous work, we developed an algorithm called Scanpath Trend Analysis (STA) that analyses eye movement sequences (i.e., scanpaths) of multiple users on a web page and identifies their most commonly followed path in terms of the visua...
Conference Paper
Full-text available
In this paper, we introduce a new concept called trending scanpath that represents the most popular scanpath among users.
Article
This year was the 17th edition of the ACM SIGACCESS International Conference on Computers and Accessibility (ASSETS 2015)¹. ASSETS 2015 took place in Lisbon, which is the capital of Portugal and is known as the city of seven hills (A Cidade das Sete Colinas). The conference was very well attended around 170 participants from all over the world. The...
Conference Paper
The number of users required for usability studies has been a controversial issue over 30 years. Some researchers suggest a certain number of users to be included in these studies. However, they do not focus on eye tracking studies for analysing eye movement sequences of users (i.e., scanpaths) on web pages. We investigate the effects of the number...
Article
Amaç: Web gündelik hayatımızda önemli bir rol oynamaktadır. Ancak web sayfaları, engellilerin ihtiyaçları gözetilerek tasarlanmadığından dolayı engelli kullanıcılar için erişilebilir değildir. Literatürde kullanıcı deneyimi araştırmalarının sayısı gün geçtikçe artmakla birlikte, bu çalışmalar engelli bireylerin ihtiyaçlarına odaklanmamaktadır. Ayrı...
Article
Full-text available
Eye tracking has commonly been used to investigate how users interact with web pages, with the goal of improving their usability. This article comprehensively revisits the techniques that could be applicable to eye tracking data for analysing user scanpaths on web pages. It also uses a third-party eye tracking study to compare these techniques. Thi...
Article
Yeliz Yesilada is an Assistant Professor at Middle East Technical University Northern Cyprus Campus (METU NCC) since 2009. She has previously worked as a postdoctoral research fellow in the School of Computer Science at the University of Manchester. She has received her B.Sc. in Computer Engineering from the Eastern Mediterranean University, Cyprus...
Article
Full-text available
Web pages are typically decorated with different kinds of visual elements that help sighted people complete their tasks. Unfortunately, people accessing web pages in constrained environments, such as visually disabled and small screen device users, cannot benefit from them. In our previous work, we show that tracking the eye movements of sighted us...
Conference Paper
Experiential transcoding aims to transcode web pages into more accessible forms based on the understanding of users' experience. Previous studies show that transcoding can improve interaction of both disabled and small screen device users. However, there is not much research in understanding the effects of experiential transcoding. In this paper, w...
Conference Paper
Full-text available
Large websites are difficult to evaluate for Web Accessibility compliance due to the shear number of pages, the inaccuracy of current Web evaluation engines, and the W3C stated need to include human evaluators within the testing regime. This makes evaluating large websites all-but technically unfeasible. Therefore, sampling of the pages becomes a c...
Article
Full-text available
Hypertext 2015 will be held in Cyprus from September 2 to 4. This newsletter article briey introduces the conference and also the venue. We hope to meet you all in Cyprus in September! http://ht.acm.org/ht2015/ https://www.facebook.com/Hypertext2015 https://twitter.com/Hypertext2015
Article
The equality of access – accessibility – is difficult to quantify, define, or agree upon. Our previous work analysed the responses of web accessibility specialists in regard to a number of pre-defined definitions of accessibility. While uncovering much, this analysis did not allow us to quantify the communities’ understanding of the relationship ac...
Conference Paper
Full-text available
Web pages are typically decorated with different kinds of visual elements that help sighted people complete their tasks. Unfortunately, this is not the case for people accessing web pages in constraint environments such as visually disabled or small screen device users. In our previous work, we show that tracking the eye movements of sighted users...
Conference Paper
Web pages are typically designed for visual interaction – they include many visual elements to guide the reader. However, when they are accessed in alternative forms such as in audio, these elements are not available and therefore they become inaccessible. This paper presents our ontology-based heuristic approach that automatically identifies visua...
Conference Paper
Web pages consist of different visual segments, serving different purposes. Typical structural segments are header, right or left columns and main content. Segments can also have nested structure which means some segments may include other segments. Understanding these segments is important in properly displaying web pages for small screen devices...
Conference Paper
Existing re-engineering, namely transcoding, techniques improved disabled and mobile Web users experience by making Web pages more accessible in constrained environments such as on small screen devices and in audio presentation. However, none of these techniques use eye tracking data to transcode Web pages based on understanding and predicting user...
Article
Full-text available
Performing controlled user experiments on small devices in naturalistic mobile settings has always proved to be a difficult undertaking for many Human Factors researchers. Difficulties exist, not least, because mimicking natural small device usage suffers from a lack of unobtrusive data to guide experimental design, and then validate that the exper...
Conference Paper
The W4A Camp is an all day event set up to discuss accessibility research. Participants decide the topics to be discussed and they also organise the session during morning devoted to the camp. It is an ad-hoc unconference born from the desire for people to share and learn in an open environment. It is an intense event with discussions, demos and in...
Article
Transcoding web pages for ease of use for small screen device users and for disabled users have been researched extensively. However, there has been very little research on transcoding web pages based on understanding and predicting users' experiences. In this paper, we discuss the concept of experience-based transcoding, called "experiential trans...
Conference Paper
Full-text available
Mobile interaction presents challenges that go beyond the traditional desktop contexts. These difficulties become even greater when considering people with disabilities or people without disabilities that experience situational impairments. Further, mobile devices and interfaces have been evolving at an astonishing rate which leads to increasing di...
Conference Paper
Full-text available
The main goal of this study is to develop an algorithm to identify a common scanpath in a given eye-tracking data. This paper provides a set of guidelines on how to develop such an algorithm. To develop these guidelines, we have conducted experiments with existing algorithms and investigated their strengths and weaknesses. The main purpose of creat...
Chapter
The usability evaluation of small devices (i.e., mobile phones and PDAs) is an emerging area of research. Compared with desktop computers, designing a usability evaluation for small devices is more challenging. Context of use, such as environmental disturbance and a user’s physical activities affect the evaluation results. However, these parameters...
Article
Mobile computing devices, such as smart phones, offer benefits that may be especially valuable to older adults (age 65+). Yet, older adults have been shown to have difficulty learning to use these devices. In the research presented in this article, we ...
Article
Full-text available
Representations of domain knowledge range from those that are ontologically formal, semantically rich to those that are ontologi- cally informal and semantically weak. Representations of knowledge are important in many tasks, one of which is the support of travel around information spaces through the identification and linking of concepts in a fiel...
Conference Paper
Full-text available
Access is what the web is 'about', it is the motivation behind its creation, and it is the rationale behind HTML. The desire to provide all users at CERN with the ability to access all documents was Tim Berners-Lee's primary goal, and this goal must also be carried through to equal access for all users. But this equality of access -- accessibility...
Article
The Web Content Accessibility Guidelines (WCAG) 2.0 separate testing into both “Machine” and “Human” audits; and further classify “Human Testability” into “Reliably Human Testable” and “Not Reliably Testable”; it is human testability that is the focus of this paper. We wanted to investigate the likelihood that “at least 80% of knowledgeable human e...
Article
Web site-evaluation methodologies and validation engines take the view that all accessibility guidelines must be met to gain compliance. Problems exist in this regard, as contradictions within the rule set may arise, and the type of impairment or its severity is not isolated. The Barrier Walkthrough (BW) method goes someway to addressing these issu...
Article
Web accessibility means that disabled people can effectively perceive, understand, navigate, and interact with the web. Web accessibility evaluation methods are needed to validate the accessibility of web pages. However, the role of subjectivity and of expertise in such methods is unknown and has not previously been studied. This article investigat...
Chapter
Full-text available
Web accessibility conjures the vision of designers, technologists, and researchers valiantly making the World--Wide--Web (Web) open to disabled users. While this maybe true in part, the reality is a little different. Indeed, Web accessibility is actually about correcting our past mistakes by making the current Web fulfill the original Web vision of...
Article
The usability evaluation of small devices i.e., mobile phones and PDAs is an emerging area of research. Compared with desktop computers, designing a usability evaluation for small devices is more challenging. Context of use, such as environmental disturbance and a user's physical activities affect the evaluation results. However, these parameters a...