Ig Ibert Bittencourt

Maria Cecília Baranauskas

Diego Dermeval
email: diegodermeval@dsc.ufcg.edu.br

Juliana Braga
email: juliana.braga@ufabc.edu.br

Roberto Pereira
email: rpereira@ic.unicamp.br

Designing for Different Users and Multiple Devices: a roadmap towards inclusive environments

Keywords: Inclusive Environments, Portability, User Interface Design, Inclusiveness, Diversity, Multiple Devices

The Web can be understood as an ecosystem of interconnected technological resources organized by rules, strategies, organizational structures, and mainly people. Such ecosystem is improving the potential to access knowledge everywhere and at any time. However, for different reasons, this technological extension is not reaching everybody yet. Those without access to knowledge are mainly people with disabilities or living in underserved communities. Nevertheless, the extension of Web technologies to different types of devices (such as mobile phones, tablets, TV) and their connections have the potential to increase the solutions to reach people with different needs through different devices. For this reason, several research and industrial studies have been proposed to design interfaces for multiple devices considering differences among users. In this paper, we present results of a systematic review on literature to build a roadmap towards inclusive environments. Additionally, the study also suggests existing tools to support the design of accessible applications for multiple devices. A significant result of this review is the lack of studies addressing underserved communities.

Introduction

Several organizations around the world have undertaken work programs to establish electronic communication via Web technologies. The Web can be understood as an ecosystem of interconnected technological resources organized by rules, strategies, organizational structures, and mainly people. As a result, this ecosystem is improving the potential of access to knowledge everywhere and at any time, and is becoming a way to tackle the challenge of providing a participative and universal access to knowledge. Universal access has been considered one of the great challenges of several International Communities around the world [START_REF] Medeiros | Grand research challenges in computer science in Brazil[END_REF] [START_REF] Calvary | A Unifying Reference Framework for multi-target user interfaces[END_REF]. This challenge is about the use of technologies to ensure access to knowledge in a participative and personalized way for the citizen, taking into account the diversity of people and, consequently, different 1 users' needs encompassing disability issues as well as social problems (e.g., people living in underserved2 communities).

The accessibility challenge regards ensuring access to information and functionalities to all potential users of technology. As a matter of fact, a valuable body of research and best practices has been developed to address Web accessibility. However, the challenges of Web accessibility have increased substantially due both to the extension of Web technologies to different kind of devices (e.g., mobile phones, tablets, TV) and to their possibility of interactions. On one hand, the Web movement beyond desktop to different devices increased the challenges of accessibility. On the other hand, this movement amplified the possibilities to ensure access to information independently of the place or the knowledge domain. For this reason, many research and industrial studies have been proposed to design interfaces for multiple devices and different userssuch as [START_REF] Calvary | A Unifying Reference Framework for multi-target user interfaces[END_REF] [3] [4] -; however, no systematic review has been conducted to provide an overview of the design of inclusive environments for different users and multiple devices.

The goal of this paper is to present results of a systematic review about interface design approaches addressing multiple devices and different users, and, at the same time, to identify the tools available to build accessible applications aiming to reach people with different disabilities and/or living in underserved communities.

This paper is organized as follows: Section 2 describes the research method of the study; Section 3 gives an overview of the studies included in the work; Section 4 presents the main results of this systematic review with a discussion on the reported results. Finally, Section 5 summarizes this work, presents our conclusions and points out future works.

2

The Method

The research in this work was undertaken as a systematic literature review (SLR) to provide a repeatable and formal process to document relevant papers about portability on inclusive social web. As a result of identifying, interpreting and evaluating their data, it is possible to find evidence on which to base conclusions according to the research questions. The conclusions are commonly used to support or contradict claims made by researchers, identify gaps in existing research, provide motivation for new research, and supply a context for the new research [START_REF] Kitchenham | Procedures for performing systematic reviews[END_REF].

According to [START_REF] Kitchenham | Procedures for performing systematic reviews[END_REF], a systematic review is composed by three phases (planning, conducting, and reporting) divided into several steps, which are: 1) Planning the Review (Identification of the need for a systematic review; Development of a review protocol); 2) Conducting the Review (Identification of research; Selection of the studies; Study Quality assessment; Data extraction and monitoring; Data analysis; Data synthesis); 3) Reporting the review (Report-writing).

Review Questions

The goals of this systematic review were: i) to summarize the research in this topic; and ii) to present a roadmap towards inclusive environments. As the goal of this systematic review was to gather knowledge about the design of inclusive environments for different users and multiple devices, the high-level question of this study was:

How researchers are designing applications for different users and multiple devices?

Based on this research question, other two more specific questions were raised. The questions and their motivations are described in Table 1. This question provides a starting point to understand how designers conduct the interface specification for multiple devices. The answer to this question is important to understand how people with different conditions are being considered in the interface design process.

RQ2. Which tools are being used to support the design of inclusive applications for multiple devices?

This question presents the different solutions (i.e., software, frameworks, authoring tools, architectures, and so on) to build portable applications for all. The answer to this question is important to identify the different solutions regarding the adopted software engineering practice.

2.2

Sources and Search Selection Criteria

The first step to perform our review was to define the search selection criteria. Due to the fact that this review has several sources to consider, two kinds of search strategies were considered (based on [START_REF] Beecham | Motivation in Software Engineering: A systematic literature review, Inform[END_REF]), which were automatic and manual search. Automatic search was done according to the specification of the search terms (i.e., search string). Although automatic search covers a large range of relevant papers, it is also important to search in specific and specialized sources to improve the coverage. For this reason, a manual search in some of the most important conferences and journals of the Human-Computer Interaction area was taken into account.

Hereafter, the search terms definition and the digital libraries (DLs) selection regarding the automatic search are explained. According to the research questions aforementioned, a set of relevant terms was defined, such as: cross-device, disabilities, underserved communities, design interfaces, approaches, multiple devices, different users, tools, and inclusive. After that, these terms were categorized and their related terms were identified. The terms were identified based on: i) expertise of the authors; ii) analysis of terms present in a HCI systematic review available at [START_REF] Almeida | Accessibility in Rich Internet Applications: People and Research[END_REF]; iii) TagCloud for HCI presented in Fig. 1 and iv) suggested topics for contributions to the Interact 2013 Conference. The related terms for the main words are described as follows:

 Tool = environment, framework, authoring, architecture, software, ambient, "reference model";  Disabilities = Inclusive, inclusiveness, inclusivity, accessibility, disability, assistive, underserved, "marginalized communities", "design for all", "universal access", elderly, "older adults", diversity;  Multiple Device = "cross-device", multimodal, migration, "different devices", "device-independent", "migratory interfaces", "distributed interfaces", "plastic user interfaces", "flexible user interfaces", "flexible interfaces", "distributed user interfaces", portability, "portable web applications", "portable systems", interoperability;  Interaction design = "adaptable interface", "adaptable user interfaces", "interaction resources", "responsive web design", "universal design", "inclusive design", "process model", "adaptable model", "system design", "meta-design".

By contrast, the set of digital libraries was defined according to the most popular and traditional DLs. However, the SpringerLink digital library was excluded due to search restrictions and its intersection with others DLs. OR "universal access" OR "universal design" OR "designing for diversity" OR "design for diversity" OR "design diversity" OR diversity) AND ("Multiple Device" OR "Cross-device" OR "Multimodal" OR migration OR "different devices" OR "device-independent" OR "migratory interfaces" OR "distributed interfaces" OR "plastic user interfaces" OR "flexible user interfaces" OR "flexible interfaces" OR "distributed user interfaces" OR portability OR "portable web applications" OR "portable systems" OR "information interoperability" OR "knowledge interoperability") AND ("Interaction design" OR "adaptable interface" OR "adaptable user interfaces" OR "interaction resources" OR "responsive web design" OR "universal design" OR "inclusive design" OR "process model" OR "adaptable model" OR "meta-design" OR "meta design" OR metadesign OR "participative design"))

Moreover, in order to perform the manual search, two relevant conferences and journals in the Human-Computer Interaction area were considered (see Table 2). It is important to note that other Journals and Conferences could have been considered for manual search, but the Journals were chosen based on their Impact Factor. In addition, we could not have access to the library of some journals, such as the International Journal of Human-Computer Interaction. With regards to conferences, we initially added the ACM SIGCHI Conference on Human Factor in Computing Systems, but the list of published articles in this conference would represent half of the whole search space, unbalancing the study.

Inclusion and Exclusion Criteria

The aim of defining a criterion is to really identify those primary studies that provide direct evidence about the research questions and also to reduce the likelihood of bias [START_REF] Kitchenham | Procedures for performing systematic reviews[END_REF]. Regarding the inclusion criteria, articles written in the last ten years related to any of the research questions were considered. The exclusion criteria involve papers not related to the research questions, papers which were not in English, short papers 3 , duplicate studies and papers before 2002 4 . The summarized inclusion and exclusion criteria are presented in Table 3.

Data Extraction

After the definition of the search and the selection processes, a data extraction process was performed by reading the abstract and screening the full-text of each one of the selected papers. In order to guide this data extraction, the data collection from Biolchini et al. [START_REF] Biolchini | Systematic Review in Software Engineering[END_REF] was adapted as follows:

─

Overview of the Included Studies

This section presents the included studies according to the automatic and manual search (see Fig. 2). Firstly, the automatic search was conducted at each digital library. Then, an iterative process was applied to exclude the not relevant papers based on the exclusion criteria. The exclusion criteria were applied according to the analysis of the abstract, full-text screening and finally the duplicate papers. In a similar way, the process was applied to the manual search. The automatic and manual query was conducted in the period between December 4 th (2012) and January 11 th (2013) and the data was extracted by two people. The results per each digital library, conference and journal are shown in Fig. 3.

Fig. 3 (Manual search) presents that the IFIP Interact (31%; 14 studies) and the W4A -Cross-disciplinary Conference on Web Accessibility (27%; 12 studies)were the largest vehicles of relevant studies about portability on inclusive web. However, other vehicles were identified as relevant when the automatic search was applied, such as the ACM SIGCHI Conference on Human Factors in Computing Systems (6.25%; 8 studies), the ACM SIGACCESS conference on Computers and accessibility (4.69%, 6 studies)and the ICCHP -International Conference on Computers Helping People With Special Needs (4.69%; 6 studies). Since this review began on December 2012, a possible cause of this decreasing in 2012 is that some papers were still under publication process, thus it is natural that some papers were not available online yet. Therefore, we can see, in general, an increase in the number of publications (based on their linear progression). The significant increase of publications on portability in inclusive web reflects the need for convergence of technologies and, at the same time, the importance of deploying inclusive solutions.

The study holds contributions from 35 countries located in all the continents. Although all the continents are represented in the included papers, there is a concentration in the Americas (26.34%) and Europe (62.44%). Table 4 presents the publications per authors country. Furthermore, according to the distribution of the included papers, most of the related papers were published in conferences (66%) instead of journals (34%), considering both the automatic and manual search.

Results

As described in Section 2, three research questions drove this systematic review.

Based on the research questions, the string search was built and the type of data extraction defined. According to the data extraction, the addressed conditions of most users were Blind or Visual Impairment (24%; 58 studies), Mental (14%; 34 studies) and Motor (14%; 34 studies). One of the important points about this information is that although the number of deaf people or with hearing impairment is relatively high in the general population, the number of studies addressing this disability in the review was very low (see Fig. 5). The following subsections present and discuss the results for the research questions. Moreover, a specific subsection discusses the works that address underserved communities, due to the reduced amount of papers identified for this audience in the study. In the end of this section, threats to the validity of this review are also discussed.

Inclusive Applications for Multiple Devices

Table 5 presents the distribution of papers according to device type. Most of the solutions were proposed for mobile phones (29.84%; 94 studies) and Web (18.73%; 59 studies). It is worth noting that the number of solutions for tablets is still small (8.25%; 26 studies); this may happen especially because tablets have started to become popular more recently than mobile phones. Nevertheless, an increasing in their use is expected since they have the potential to provide access to underserved communities. Although there are 29 studies in other categories of Device Types, 21 studies (6.67%) are not related or did not define the device. Table 6 presents the distribution per tool type. Frameworks and platforms are in the top of the list, while the Software Product Line (SPL) approach is not mentioned, suggesting a gap between the Human Computer Interaction and the Software Engineering issues. SPL is one of the most sophisticated concepts in the Software Engineering area with regard to software reuse and flexibility, since it allows a strategic reuse that provides a platform which can be easily adapted according to users' specific needs in a specific domain [START_REF] Pohl | Software Product Line Engineering[END_REF]. In addition, it can be noticed that half of the papers that presented tools provide an inclusive solution (50%). However, only 15% of the selected papers proposed inclusive tools for multiple devices, as illustrated in Fig. 6. It is important to observe that by inclusive tools we mean support tools to generate inclusive applications. Additionally, most of the inclusive tools for multiple devices are Frameworks (37%) and Platforms (32%). The list of papers that propose inclusive tools for multiple devices is presented in Table 7 5 (papers which did not define the tool type were not included). Fig. 7 presents the type of empirical study applied to evaluate the tools. More than 50% of the works applied evaluation by an empirical case study. In addition, only 25% of the works applied some kind of experiment. By contrast, survey studies were 5%. It is also important to identify which of these studies address the design for diversity. For this reason, Table 8 presents them grouped by tools for one target audience and for diversity. As a result, only 4.54% (6 studies) of the inclusive tools for multiple devices (see Fig. 6) address inclusive tools for different users, while 7.63% (10 studies) address tools for one target device.

Interface Design Approaches for Diversity

The distribution of the included studies according to the Interface Design approaches (Table 9) shows that more than 50% of the studies apply User-centered, participatory or automatically generated approach. However, more than 15 interface design approaches were identified, which turned the data classification, organization, and analysis much sparse. Moreover, as presented in Table 10, only few studies (13.79%; 20 studies) present a design approach considering user diversity in the application development. Conversely, although there are 19 studies addressing Interface Design approaches for diversity, only 3 (three) studies also addressed multiple devices, as depicted in Table 11. Among these studies, two of them apply automatic interface generation and the other two use participatory design. Besides, two studies evaluated their tools by some kind of experimental research, while the other two papers performed evaluation by an empirical case study.

Solutions for Underserved Communities

This section discusses the studies with a focus on underserved communities. Indeed, only 12 studies addressed this topic which is also the less discussed target audience identified in this systematic reviewrepresenting only 5% (see Fig. 5). The full list of studies attending underserved communities is presented in Table 12. It is worth noting that less than half of the underserved people studies involve researchers from countries where the researches were developed. Another important point to highlight is the reduced number of studies about underserved people coming from the HCI community, which means there is a need for cooperative work from different communities with the Human-Computer Interaction community.

As a roadmap regarding studies about underserved communities, most of the studies proposed the use of mobile devices as the best technology. The main reason seems to be that underserved communities have bad access to electricity, internet, and so on. Moreover, we realized that several studies with regards underserved communities refer also to illiterate people. In addition, the most common user interface type was based on Voice or Web. Although Voice approach is commonly used, it does not solve the problem of illiteracy. Another important point is that only 2 studies proposed a software solution, while the others proposed a reference model or a new hardware. Finally, only four studies address the context of developing country.

Discussion and Other Related Work

This section focuses on how the systematic review tackled the three research questions and discusses about the important conclusions obtained from the analysis of the papers included in this review. As a result of this review, it was possible to identify the interface design approaches and the tools according to specific user conditions and also to specific devices.

With regards to the RQ1 (Which interface design approaches are being used to address multiple devices and users with different conditions?), only a very limited number of papers (3 studies, as presented in Table 11) was identified from the whole list of studies (see Fig. 2), representing 1.70%. One important point is that the Interface design approaches were only the Automatically Generated Interface (from 2012) and the Participatory Design (from 2008 and 2011). This means that the studies were focused on ID approaches to tackle the first phases of software development lifecycle (before software implementation), while other part of the studies were focused on implementation, test, and deployment phases. Only one study raised (SIEEE11) the importance of user involvement during software evolution.

Concerning RQ2 (Which tools are being used to support the design of inclusive applications for multiple devices?), six studies presented solutions for the design of inclusive applications for multiple devices (see Table 8), representing 3.41% of the whole data extraction (see Fig. 2). According to the data, the types of technologies used to design inclusive applications for multiple devices were Platform (from 2007), the Framework (from 2011 and 2012) and the Application (from 2009). Thus, only three types of technologies were proposed. New strategic approaches for reuse and flexibility were not addressed, such as the Software Product Line. In comparison to the Software Engineering approaches used by the identified studies, the SPL may support higher reduction in software development costs, higher increase of software quality, faster time to market and higher reduction in maintenance efforts [START_REF] Pohl | Software Product Line Engineering[END_REF]. In this way, with these advantages, it is intriguing that this approach has never been used in the design of tools to support the development of such applications. Thus, this information could demonstrate some level of detachment between HCI and Software Engineering. In contrast, it may also demonstrate that the software engineering methodologies need to advance in order to take into account inclusiveness as a very important non-functional requirement. Through the analysis of the papers included in this review, it could also be noticed the interest of several studies to evolve Web technologies. Indeed, some of these studies have explored the Semantic Web and Ontologies technologies to automatize interface generation.

Furthermore, the results reported in this review also show that the underserved audience is still under addressed by inclusive design studies (see Table 12). By contrast, the number of studies that attends the elder audience is substantial (Fig. 5)which reveals the concern of researchers with the older population. Considering the devices used in the studies, the large presence of mobile phones in these studies can be highlighted (see Table 5). It can also be noted a smaller amount of works focusing on Tablets (compared to mobile phones); however it is expected an increase in the number of studies which address this kind of device as well as smartphones because both devices are becoming more and more popular. Additionally, it can be perceived a trending convergence of devices in the studies. All the identified inclusive design works for multiple devices (Table 7) were published in the last seven years.

For the best of our knowledge, there is no previous systematic review that answers the research questions of this work. Nevertheless, some analyzed studies present secondary studies (surveys) that address HCI aspects for the design of multiple devices and different kinds of disabilities (e.g., [START_REF] Loureiro | Multi-touch as a Natural User Interface for elders: A survey[END_REF] [12] [13]).

Threats to Validity

This section discusses the threats to validity that might have affected the results of this systematic review. The review protocol was validated to ensure that the research was as correct, complete and objective as possible. However, possible limitations in two moments of the review process were identified: in the publication selection and in the data extraction.

The search for publications was performed in two major steps: (i) automatic search and (ii) manual search. In step (i) there is a limitation because the search string could not be used in SpringerLink library, which possibly leads to a reduction in the considered studies. In step (ii), it was identified a limitation concerning the papers included in the review. The manual search was performed only on a limited set of journals and conferences and it was expected that relevant studies published in other journals or conferences would be captured through the automatic search realized in the previous step. However, it cannot be guaranteed that all related papers published are included in this review. Moreover, it is possible that some kind of inaccuracy or misclassification have occurred in the data extraction performed in this systematic review, mainly because the data extraction was done individually by the researchers.

Conclusions

Web movement beyond desktop to different devices increased the challenges for accessibility, while, at the same time, this movement amplified the possibilities to ensure access to information for all. This paper presented a systematic review on the design for different users and multiple devices. Thus, a roadmap towards inclusive environments was drawn based on the extracted data in order to answer two research questions: "RQ1. Which interface design approaches are being used to address multiple devices and users with different conditions?" and "RQ2. Which tools are being used to support the design of inclusive applications for multiple devices?". A systematic review protocol was defined and the automatic and manual search returned a total of 4061 studies between 2002 and 2012. After applying the exclusion/inclusion criteria, it led to the inclusion of 176 studies in the review.

The results indicated that: i) the HCI community is presenting solutions for the software development lifecycle until the software deployment, but only few researches are considering software evolution and interaction design during use time; ii) there is a gap between the software engineering and the HCI communities regarding the subject, because some more recent software engineering approaches for development and maintenance are not in the analyzed work yet; in the same way that software engineering approaches need to consider inclusiveness as an important non-functional requirement; iii) a connection between the HCI and the Semantic Web and ontologies communities could be identified. Some included studies explored Semantic Web and ontologies technologies to automate user interface generation; iv) it is important for the HCI community to increase the number of studies addressing underserved people and also to interact with local research communities addressing this problem; v) there is a growing curve on the number of publications on the subject addressed by this work, in the last decade.

As further work, we expect to: i) diminish the threats to validity, ii) analyze the studies according to each disability, iii) analyze each ID approach based on software development lifecycle, iv) evaluate each provided tool by developing inclusive envi-ronments, v) propose new ID approaches to cover software development, maintenance, and dynamic evolution, and finally, vi) extend the study to consider other research questions and more papers of relevant authors identified in this systematic review.

Fig. 1 .

 1 Fig. 1. TagCloud for HCI [8].

Fig. 2 .

 2 Fig. 2. Search process and selected studies.

Fig. 3 .

 3 Fig. 3. Automatic and Manual results.

  From a temporal point of view, it is noticed in the trend curve an increasing number of publications in the context of this review since 2003 (see Fig.4). It is important to note that there are no works from the year 2002. The first study was published only in 2003. By contrast, there is a decrease in the number of publications in some years(2008, 2009, and 2012).

Fig. 4 .

 4 Fig. 4. Distribution of publications per year.

Fig. 5 .

 5 Fig. 5. Distribution of publications per target audience.

Fig. 6 .

 6 Fig. 6. Graphic about inclusive tools for multiple devices.

Fig. 7 .

 7 Fig. 7. Type of Empirical Study of the Inclusive Tools for Multiple Devices

Table 1 .

 1 Research Questions and Motivations.

	Research Question	Motivation
	RQ1. Which interface design approaches are
	being used to address multiple devices and
	users with different conditions?

Table 2 .

 2 Relevant journals and conferences on the Human-Computer Interaction area.

	Journals
	1. International Journal of Human Computer Studies
	2. Interacting with Computers
	Conferences
	1. IFIP INTERACT
	2. Cross-Disciplinary Conference on Web Accessibility

Table 3 .

 3 Inclusion and exclusion criteria.

	Studies published since 2002
	Exclusion criteria
	Short-papers
	Non peer-reviewed studies
	Studies that are not related to research questions
	Duplicated studies
	Studies before 2002
	Non English papers

Inclusion criteria

Peer-reviewed studies that provided answers to the research questions Studies that focus on design approaches for multiple devices Studies that focus on design approaches for different users' needs Studies that focus on assistive technologies for different users' needs

Table 4 .

 4 Publications per country

	Country	Works	Total (%)
	United States of America	29	14.15%
	United Kingdom	27	13.17%
	Brazil	16	7.80%
	Spain	15	7.32%
	Portugal	11	5.37%
	Belgium	10	4.88%
	Italy	10	4.88%
	France	9	4.39%
	Germany	9	4.39%
	Greece	7	3.41%
	Japan	7	3.41%
	Austria	6	2.93%
	Finland	6	2.93%
	Canada	5	2.44%
	Australia	4	1.95%
	Sweden	4	1.95%
	South Korea	3	1.46%
	Norway	3	1.46%
	South Africa	3	1.46%
	Others	21	10.34%

Table 5 .

 5 Distribution per device type

	Device type	Works	Total (%)
	Mobile Phones	94	29.84%
	Web	59	18.73%
	Desktop	49	15.56%
	PDA	44	13.97%
	Tablet	26	8.25%
	TV	14	4.44%
	Others	29	9.21%

Table 6 .

 6 Distribution per tool type

	Tool type	Works	Total (%)
	Framework	29	16.48%
	Application	24	13.64%
	Reference Model	21	11.93%
	Platform	20	11.36%
	Architecture	7	3.98%
	Authoring	4	2.27%
	MDA	3	1.70%

Table 7 .

 7 List of support tools to generate inclusive tools for multiple devices.

	Study Ref.	Paper Title	Technology Type
	SACM19	Distributed Intelligence: Extending the Power of the Unaided, Individual Human Mind	Platform
	SACM20	Towards Ubiquitous Accessibility: Capability-based Profiles and Adapta-tions, Delivered via the Semantic Web	Platform
	SACM27	MyUI: Generating Accessible User Interfaces from Multimodal Design Patterns	Framework
	SACM62	The Potential of Adaptive Interfaces as an Accessibility Aid for Older Web Users	Platform
	SACM68	Accessibility of Dynamic Adaptive Web TV Applications	Framework

Attuning speech-enabled interfaces to user and context for inclusive design: technology, methodology and practice Application

Table 8 .

 8 List of inclusive studies for multiple devices based on the target audience.

	Technology Type	For one Target Audience	For Diversity
	Framework	SACM27; SACM75; SIEEE07	SACM68; SIEEE11; SIEEE30; SScopus38
	Platform	SACM19; SACM20; SACM62; SACM70; SSD13
	Application	-	SScopus80; SScopus85
	API	SIEEE10	-
	Architecture	SScopus69	-

Table 9 .

 9 Distribution per Interface Design Approach

	ID Approach	Works	Total (%)
	User-Centered	31	19.62%
	Automatically Generated	27	17.09%
	Participatory	25	15.82%
	Model-Based	17	10.76%
	Task-Centered	15	9.49%
	User-Sensitive Inclusive Design	10	6.33%
	Design Per Target Device	9	5.70%
	Ethnographic	9	5.70%
	Scenario-Based	7	4.43%
	Others	8	5.06%

Table 10 .

 10 Distribution per focus on diversity

	ID Approach	No Disability For one Target Audience For Diversity
	Participatory	4.83%	6.90%	4.14%
	Automatically Generated	11.03%	4.83%	3.45%

Table 11 .

 11 List of studies from Table10for Diversity and Multiple Devices.

	Study Ref.	Paper Title	ID Approach	Study Type
	SACM68	Accessibility of Dynamic Adaptive Web TV Applications	Automatically Generated	Case Study
	SIEEE11	A Framework for Designing Flexible Systems	Participatory	Case Study
	SScopus85	Attuning speech-enabled interfaces to user and context for inclusive design: technology, meth-odology and practice	Participatory	Controlled Experiment

Table 12 .

 12 List of studies addressing underserved communities.

	Study Reference	Paper Title	Countries
	SACM30	Comparing Semiliterate and Illiterate Users' Ability to Tran-sition from Audio+Text to Text-Only Interaction	Canada and India
	SACM41	Designing with Mobile Digital Storytelling in Rural Africa	Australia and South Africa
	SACM52	Universal Accessibility As A Multimodal Design Issue	Spain and Serbia and Montenegro
	SACM58	Cultural Coding and De-Coding as Ways of Participation: Digital Media for Marginalized Young People	USA and Belgium
	SACM86	Technology-Supported Cross-Cultural Collaborative Learn-ing in the Developing World	USA

In this paper, we consider the term "different users" or "different conditions" as the users with disabilities (sensorial impairment, motor impairment, and cognitive impairment), social problems (underserved or illiterate people) and ageing (elderly).

In this paper, we consider the term underserved as the people or communities living in areas without good access to technology and/or internet, such as rural areas and low income areas in the periphery of large cities.

Short-papers were excluded because they usually represent ongoing research.

Due to the rapid evolvement of web technologies and hardware devices, the older inclusive solutions for multiple devices lack the benefits and potential of current devices. For this reason, we decided to limit our review to the last decade.

The list of the papers is available at http://www.nees.com.br/interact

Acknowledgements

This work has been supported by the Brazilian Institutions: Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), processes: 150113/2013-7 and 560044/2010-0 (EcoWeb Project).


Maria Claudia Buzzi
email: claudia.buzzi@iit.cnr.it

Marina Buzzi
email: marina.buzzi@iit.cnr.it

Barbara Leporini
email: barbara.leporini@isti.cnr.it

Maria Teresa Paratore
email: maria.paratore@iit.cnr.it

Vibro-Tactile Enrichment Improves Blind User Interaction with Mobile Touchscreens

Keywords: Accessibility, usability, mobile accessibility, haptic UIs, blind

Interaction via mobile devices is a challenge for blind users, who often encounter severe accessibility and usability problems. The main issues are due to the lack of hardware keys, making it difficult to quickly reach an area or activate functions, and to the new way of interacting via touchscreen. A touchscreen has no specific reference points detectable by feel, so a blind user cannot easily understand exactly where (s)he is positioned on the interface nor readily find a specific item/function. Alternative ways to provide content are mainly vocal and may be inadequate in some situations, e.g., noisy environments. In this study we investigate enriching the user interfaces of touchscreen mobile devices to facilitate blind users' orientation. We propose a possible solution for improving interaction based on the vibro-tactile channel. After introducing the idea behind our approach, two implemented Android Apps including the enriched user interfaces are shown and discussed.

Introduction

In recent years, the development of more sophisticated smartphones with touchscreens has changed interaction modalities, while the use of hardware keys to quickly reach or activate specific functions has been decreasing. Touchscreens are completely smooth, so detecting specific user interface (UI) parts and elements is difficult for someone who cannot see the screen. Alternative ways to provide content visible on the touchscreen are mainly based on vocal channels through a voice TTS (Text-to-Speech), which may not always be enough for fully accessible and usable interaction. Vocal feedback may not work well in noisy environments; moreover, in some situations (e.g. during classes, meetings, speeches) users may prefer something more 'silent'. Several aspects of interacting with a touchscreen can be improved to make screen exploration more satisfactory for the blind. In this paper we focus on a tactile-based solution to improve mobile interface exploration by blind users when interacting via touchscreen. The tactile channel is more immediate and direct for the blind --cortical brain areas normally reserved for vision may be activated by tactile stimuli [START_REF] Sadato | Activation of the primary visual cortex by Braille reading in blind[END_REF]. In this perspective, a possible solution for improving interaction based on the vibrotactile channel is presented. After an introduction to related works in the field and to the main usability issues encountered when a blind person interacts with a touchscreen, our approach will be discussed and described through examples.

Related Work

Several studies in the literature describe the importance of providing a user with appropriate mechanisms and techniques for better orientation on the user interface. In [START_REF] Goble | The travails of visually impaired web travellers[END_REF], the authors conducted a pilot study to investigate analogies between the real world and Web navigation. For the authors, organized content can benefit a reader only if (s)he is able to move around it with accuracy and agility, and is able to quickly discover and absorb its organization. Kane et al. compared how blind and sighted people use touchscreen gestures, and proposed guidelines for designing accessible touchscreens. Blind subjects preferred gestures that use screen corners, edges, and multi-touch, enabling quicker and easier identification, and suggested new gestures in well-known spatial layouts, such as a qwerty keyboard [START_REF] Kane | Usable gestures for blind people: understanding preference and performance[END_REF]. This study observed that referencing points are particularly useful and preferred by blind users to better move around the interface. Arroba et al. proposed a methodology for making mobile touchscreen platforms accessible for visually impaired people based on a functional gesture specification, a set of guidelines to assure consistency of mobile platforms and the customization of input application [START_REF] Arroba | A Methodology for Developing Accessible Mobile Platforms over Leading Devices for Visually Impaired People[END_REF]. These studies offered guidelines valuable for further developments.

Recently, Bonner at al. developed an accessible eyes-free text entry system that offers multi-touch input and audio output. The system, implemented on Apple's iPhone and tested with ten users, showed better performance in terms of speed, accuracy and user preference with respect to the text entry component of VoiceOver [START_REF] Bonner | No-Look Notes: Accessible eyesfree multi-touch text entry[END_REF]. This solution focuses only on the text-entry providing audio feedback, which may not work well in some situations.

Koskinen et al. investigated the most pleasant tactile clicks, comparing piezo actuators vs a vibration motor, finding that subjectively the first was preferred [START_REF] Koskinen | Feel-good touch: finding the most pleasant tactile feedback for a mobile touch screen button[END_REF]. In agreement with previous studies, results showed that tactile feedback improves the usability of virtual buttons pressed with the fingers, since the user is able to feel the object of interaction. Brewster and Brown proposed the use of a new type of tactile output: structured tactons, or tactile icons, i.e., abstract messages that can be used to communicate information. A tacton is characterized by parameters such as frequency, amplitude and duration of a tactile pulse, but also rhythm and location [START_REF] Brewster | Tactons: structured tactile messages for non-visual information display[END_REF]. Using tactons could enhance accessibility of mobile devices for blind users as well as for sighted people in motion. Qian et al. identified the salient features of tactons when integrated with a mobile phone interface. Findings indicated that the best results use simple static rhythms, with differences in each pulse's duration. However, to ensure accurate perception, the dimensions in which paired tactons differ should be limited [START_REF] Qian | Towards identifying distinguishable tactons for use with mobile devices[END_REF]. Yatani and Truong proposed the use of multiple vibration motors embedded in the back of the mobile touchscreen device to convey tactile feedback, providing semantic information about the touched object. They showed that users can accurately distinguish ten vibration patterns, and that the proposed system enables better interaction in an eyes-free setting than devices without tactile feedback or using only a single vibration motor [START_REF] Yatani | SemFeel: a user interface with semantic tactile feed-back for mobile touch-screen devices[END_REF]. However, these solutions mainly rely on hardware add-ons for providing haptic feedback while our approach offers a non-invasive/intrusive software solution, that has no impact on the usual interaction of blind users.

Other studies have investigated the use of tactile aids to enhance blind user interaction on touchscreen devices. In a preliminary study, Magnusson et al. investigated the use of haptic and speech feedback to make a digital map on a touchscreen more accessible [START_REF] Magnusson | Pointing for non-visual orientation and navigation[END_REF], developing a prototype application that uses vibration to help blind users understand a map layout. This solution requires a time-consuming pre-processing of each map [START_REF] Poppinga | TouchOver Map: Audio-Tactile Exploration of Interactive Maps[END_REF]. Our approach is conceptually similar to this last work since we use a mix of audio and vibration for easily detecting areas of interest on the user interface. However, despite all this research, to the best of the authors' knowledge, effective adhoc enrichment of general-purpose touchscreen user interfaces via software for easier orientation of blind persons has not yet been presented.

Interacting with a Touch Mobile Device: Usability Issues

To identify main accessibility and usability issues encountered by blind users when interacting with touchscreen mobile devices, we evaluated the interaction with Android-based and Apple mobile devices. In both cases, the inspection was carried out by all the authors (one of whom is blind) interacting with the touchscreen via screen reader (TalkBack on Android devices, VoiceOver on Apple ones) and gestures. Throughout the evaluation process, sighted authors avoided looking at the screen by activating the "screen curtain"1 functionality. More details on the applied methodology are available in [START_REF] Leporini | Interacting with mobile devices via VoiceOver: usability and accessibility issues[END_REF]. In the following we summarize the main issues observed:

 Lack of logical navigation order, to ensure the content is correctly sequentialized: the problem occurs when trying to navigate content and elements sequentially via swipe gestures ("next" -flick right -and "previous" -flick left). In this case some incongruences regarding the correct logical order occur when visiting or expanding an item.  Unsuitable handling of focus: the problem especially occurs when editing a text field within a form composed of several control UI elements. When activating an edit field by a double tap, the system focus moves onto that field and the screen reader announces the editing modality. By exploring and clicking on the virtual keyboard letters, the focus moves on the keyboard and the user loses the editing focus point. (S)He is unable to quickly check what was edited because to do this, it is necessary to explore the UI again. This issue also arises when filling in a group of form elements. This process disorients the user and can make the action difficult and frustrating.

 Lack of orientation on the UI: the user can explore content on the screen by either (1) going forward and backward in a sequential order through swipe gestures, or (2) touching a point on the screen and then proceeding through the next and previous flick. This means that the user may encounter some difficulty or frustration when reading content. For instance, when reading a mail, the user has to read the message header before catching its content, unless (s)he is able to click in the exact starting point of the text of message. When clicking, the focus moves onto the clicked place and the user can start the reading from there.

The Proposed Solution

To address the usability issues discussed in the previous section, we propose an approach based on the use of haptic technology. Our proposal aims to support blind users as they explore and interact with content on a touchscreen. Preserving the original UI layout, this solution provides extra information and feedback for better and easy identification of the UI elements or parts.

For instance, for the Web, the W3C WAI-ARIA (Accessible Rich Internet Applications) suite2 suggests the use of landmarks and region roles to allow developers to divide the Web page content into several parts, to create the logical partitioning of UI areas. In this way, the user is able to quickly obtain an overview of the page structure. Unfortunately this standard is still rarely applied. Moving from web to mobile devices, phone apps --as well as any system application --could greatly enhance applying a similar strategy to the main UI parts. In our study we decided to apply the "Logical partitioning" of UI elements to touchscreen interfaces of mobile devices to make the main parts of the UI easily and rapidly detectable. To this aim, we use reference cues (haptic mechanism) to help the user recognize those parts. Reference cues are particularly important for blind users in order to better orient themselves and move around a real and virtual space [START_REF] Goble | The travails of visually impaired web travellers[END_REF]. Depending on the UIs, haptic tags are added to help a blind user localize a specific part or elements on the interface.

To test our approach, we developed a prototype for an Android device, specifically a Samsung Galaxy Nexus running Android 4.2. The solution proposed herein leverages Android's support for accessibility and aims to provide developers with a simple yet versatile tool that can be used to improve the UI usability for blind users. We will describe our approach in practice through some examples in Section 5.

Methodology

According to the Model-View-Controller (MVC) software design pattern, logic and presentation must be strongly separated. Any Android application should be 'natively' MVC-compliant, since Android development guidelines require UIs to be described entirely by means of XML files. We took advantage of this principle to develop a simple add-on that can be used to enrich our UIs. We defined a graphical object with customizable behaviour in terms of accessibility. The goal is to offer developers a flexible tool for enriching UIs in order to improve their accessibility. XML attributes define the accessibility property of a cue and allow customizing any cue through spoken messages, sounds and vibrations. This improvement is nearly seamless since it will only require modifying an XML file to configure the cue's parameters. In the following, we refer to this kind of cue as CAC: Customizable Accessibility Cue. The XML snippet shown below represents a typical CAC, provided with a spoken message, a vibrating pattern and a sound. Once it is inserted into a layout XML file, it is rendered by Android as a 'reactive' colored ball, as shown in Fig. 1.

<org.cnr.iit.accessible.CustomAccessibleButton android:id="@+id/ballBtn01" android:layout_width="fill_parent" android:layout_height="20dp" android:layout_gravity="top" android:layout_margin="5dp" android:paddingTop="10dp" cnr:customMsg="custom spoken message" cnr.vibPattern="0,100,100,100" cnr:customSound="mySound" /> Fig. 1. A vibrating and speaking cue also associated with a sound, graphically rendered on a UI by a colored ball.

Applying the methodology to real cases

The proposed solution described above was tested on two real applications: a dial pad and an email client. The procedure was aimed at identifying the most suitable areas to put the cues and related feedback: a single event or a combination of events chosen from among a single vibration, vibrating pattern, speaking feedback and sound feedback, to better identify the different logical areas for each UI. We also improved the applications from other points of view, whenever their usability could be further improved. The main goal was to 'mark' the critical interaction areas by adding the customizable accessibility cues (CACs) to the layout XML files.

In the first prototype, the CACs to mark each logical session were points placed on the left side of the screen. A preliminary test with a blind user highlighted that this solution could have been misleading, since the hints were available only when exploring a narrow area of the screen. To resolve this issue, each CAC on the UI was 'stretched' (by means of proper dimension attributes) to become a horizontal strip. A pilot test was carried out with two blind users in order to assess and improve the proposed approach on two applications. The users were asked to perform five tasks using the Samsung Galaxy Nexus provided by the authors; the test was carried out in a laboratory applying the Think Aloud protocol. We first introduced users to our general idea of marking the main UI parts to support the exploration. No specific indication on how those markers were placed or implemented (audio and tactile) was given. The valuable feedback we received allowed us to refine both the haptic cue, size and vibration time, and the feedback provided, to enhance user interaction experience. All of the tests were performed after having enabled and suitably configured the Android's screen reader TalkBack.

5.1

The dial pad

In order to choose the better locations of the CACs, we identified the main interaction areas: the status bar (battery indicator, mobile network, time, etc.); numeric display area (where the number the user is dialing is visible), numeric keyboard (to dial the number), call and delete buttons; navigation bar (home and back buttons). Then we placed four CACs to separate these five areas. The uppermost and the lowest were associated with a sound both to highlight the boundaries of the part of the UI strictly related to the dial pad, and at the same time, marking the status --at the top --and the navigation --at the bottom --bars. These hints helped avoid accidentally pressing of one of the smartphone's built-in soft-keys that compose the status and the navigation bars. The intermediate cues were placed to highlight the other areas: the beginning and end of the numeric keyboard is marked by means of a vibrating pattern, thus making it easy to detect also the numeric display area and the call and delete buttons. Blind users performed two tasks: (1) dialing a call and (2) checking the phone number on the numeric display area. Blind users were able to perform the tasks and reach the desired areas easily and rapidly. While performing our tests, we noticed that other enhancements could be made to improve the usability when dialing a number: the app was modified in order to have each number announced, both when hovering over the relative button and when double clicking it, i.e., when the number was selected. In order to check the correctness of the dialed numbers, a "spoken message event" was added when hovering over the number display.

5.2

The email client K-9 is an open-source email client based on the Email application shipped with the initial release of Android. The application is quite complex and offers a complete environment in which to organize and compose emails. Once the appropriate XML layout files were identified, we introduced the cues according to the principle of highlighting main/critical interaction areas. The application was tested by two blind users considering three tasks: (1) browsing the list of incoming emails (2) reading an email and (3) composing an email. When browsing the inbox (1) it was necessary to border the UI to highlight the email list, with one CAC on the top and one on the bottom of the list. When reading an email (2) it was necessary to mark the email text; the cues were positioned as in (1). In the 'Compose' UI (3) a cue was placed before the softkeyboard to separate it from the editing area. These cues were all associated with the same sound since they share the same function of 'UI border'. Following the suggestions of the two blind users who tested the applications, other improvements were made to enhance the usability of text fields: a sound was associated with the event of a text field getting the focus, thus becoming suitable for filling. Moreover, to favor their detection, the text fields were announced by a 100-msecvibration -normally --or a 300-msec-vibration --if the text field held the focus.

Conclusions

In this work we discussed how the principle of the "Logical partitioning of UI elements" can be applied to a mobile interface in order to enhance touchscreen interaction for blind users. The proposed solution is based on a customizable combination of haptic and audio feedback that can be placed programmatically on UIs with usability problems. Only vocal feedback may not work well in noisy environments or cannot be used during classes, meetings, speeches, etc. The Customizable Accessibility Cue (CAC), a flexible add-on for enriching the UIs with spoken messages, sounds and vibrations, was developed. To test our approach, we considered two Android applica-tions, a telephone and an email client. A pilot test was conducted with two blind persons, who provided enthusiastic and positive feedback concerning the usefulness of the proposed solution, and useful feedback for refining on the UIs. Future work will include some improvement of the methodology, e.g., expanding the number of UIs and identifying the potential best set of CACs for each UI; using different short sounds to announce useful information, such as focus shifting from one area to another, or to provide an additional confirm for number editing on the phone keypad, etc. Furthermore, we need to make a user test with a group of blind persons in order to evaluate their performance interacting with both the simple and enriched user interfaces, gathering quantitative data for evaluating and improving the proposed solution, which is potentially applicable to touchscreens of any device.

Fig. 2 .

 2 Fig. 2. The telephone app with the CACs introduced to improve its usability.

Fig. 3 .

 3 Fig. 3. Position of the CACs delimiting interaction areas in three UIs of K-9, respectively: mail browsing, single message view, mail composer.

http://www.apple.com/accessibility/iphone/vision.html

http://www.w3.org/WAI/intro/aria