Piia Nurkka
email: piia.nurkka@tut.fi

"Nobody other than me knows what I want": Customizing a sports watch

Keywords: customization, sports watch, satisfaction, user experience

In order for companies to effectively use customization as a design strategy, there should be understanding on what users would like to customize and why. This study explores the use of customization features of sports watch in order to assess the extent of customization, and to identify reasons for customization in this context. Survey data from 100 users of a sports watch were analyzed to understand how they use the different customization features: general preferences, functionality and appearance. The findings show that although the users vary in the use of customization, they state similar reasons for customization: control, ease-of-use, increased effectiveness, and better fit to personal preferences. The motivation to customize in this context is for the most part related to autonomy: to the sense of control the user has by having the tool to adapt the product according to own preferences, wants and needs.

Introduction

Customization features of technology are designed to provide users with control over appearance and functioning, thus increasing its personal relevance to an individual [START_REF] Oulasvirta | Motivations in personalisation behaviour[END_REF]. The ability to customize is a means to establish a closer connection between users and products thereby enabling them to determine appropriate product characteristics for themselves, and to meet their functional and hedonistic needs [START_REF] Weightman | People are doing it for themselves[END_REF].

Customization as a product feature is attractive with sensible promises of benefits to customers and companies alike. Customized and more accurate offerings can provide customers with superior value [START_REF] Sunikka | Applying text-mining to personalization and customization research literature -Who, what and where?[END_REF], facilitate positive experiences, and increase satisfaction with the product [START_REF] Sung | Pimp My Roomba": designing for personalization[END_REF]. Therefore, personalization may lead to positive brand associations and increase brand loyalty [START_REF] Oulasvirta | Motivations in personalisation behaviour[END_REF]. This can translate to increased cash flows and profitability for companies [START_REF] Ansari | E-customization[END_REF].

Research on customization of technological products has for the most part been confined to certain products, service contexts or points of views. For example, much research on customization of mobile and smart phones has been conducted (e.g. [START_REF] Häkkila | Personal customisation of mobile phones: a case study[END_REF][START_REF] Ventä | My phone is part of my soul[END_REF][START_REF] Tossell | An empirical analysis of smartphone personalisation: measurement and user variability[END_REF]). In addition, in a desk top context studies on customization can be found on PCs [START_REF] Blom | Theory of personalization of appearance: why users personalize their pcs and mobile phones[END_REF], software [START_REF] Page | User customization of a word processor[END_REF], and web site interfaces [START_REF] Marathe | What drives customization?: control or identity?[END_REF]. On the other hand, research has often focused on a certain type of customization, with dominance of appearance customization over functional. The different types of customization deliver different value for the user: appearance customization provides aesthetic value [START_REF] Blom | Personalization-a taxonomy[END_REF], whereas functional customization provides functional value improvements. Functional value, for instance as interaction efficiency [START_REF] Häkkila | Personal customisation of mobile phones: a case study[END_REF], may lead to fulfillment of basic human needs, such as control and autonomy [START_REF] Marathe | What drives customization?: control or identity?[END_REF].

This study explores the use of customization features of a sports watch. The aims were to identify the extent to which customization features are used, the kind of customization features used, and the reasons for their use of customization. In addition, we wanted to understand if and how users differ in relation to customization, and if customization affects satisfaction with the product. The study gives insight into customization in a new context and the results can be used to inform design of customization that aims at enhancing user experience.

The paper is organized as follows: Section 2 starts with the definition of customization used in this research, and then reviews the related work on the topic. Section 3 describes the current study. Section 4 presents the results of the study. First, the extent of customization is reviewed generally, and secondly, by the types of customization separately. Last, the reasons for customization are reported. Finally, the results and limitations of the study are discussed in Section 5.

Related work

2.1 Defining customization. In HCI and related literature different terms on the concept of customization have been used. The concept means a process that changes the functionality, interface, information content, or distinctiveness of a system to increase its personal relevance to an individual [START_REF] Blom | Theory of personalization of appearance: why users personalize their pcs and mobile phones[END_REF]. However, the definition does not state who the actor in the process is: the process can be either user or system initiated. Sunikka & Bragge [START_REF] Sunikka | Applying text-mining to personalization and customization research literature -Who, what and where?[END_REF] have reviewed the literature and suggest a personalization framework in which the user involvement in the process is at the basis and is what makes the distinction between the terms. Customization should be used if the personalization process is user (or customer) initiated, whereas personalization should be used if the system initiates the process. In user-initiated customization, the user himself manipulates aspects of his device or system or configures content of a website based on his individual needs and wants (e.g. changes the ringtone or installs a new application on a smartphone). On the contrary, in the system initiated personalization the system/device adapts content using information about the user or his behavior captured by the system/device. The personalization is implicit as the user may not be aware of it, whereas in customization the user controls the changes. Following Sunikka & Bragge's [START_REF] Sunikka | Applying text-mining to personalization and customization research literature -Who, what and where?[END_REF] suggestion, the term customization is used in this paper. Customization is defined as user-initiated modifications to the functionality, content or interface (functionality-based customization) or appearance of the device (appearance-based customization) to increase its personal relevance to an individual. When referring to the related literature, the term customization is used instead of personalization when the question is about userinitiated process even though the term personalization may have been used in the original work.

2.2

Use of customization features.

Research suggests customization brings many positive aspects. However, to what extent do users actually use the offered customization options? Häkkilä & Chatfield [START_REF] Häkkila | Personal customisation of mobile phones: a case study[END_REF] examined the process of customization of mobile phones with 60 users during the first months of usage. The results illustrate active customization of the phone, with most customization occurring shortly after using the new phone for the first time. They found 11 out of the measured 17 features were customized, and nearly all had customized the most commonly customized features: the ringing tone, audio profiles and background image. The least customized features were generally more complicated to configure. Customization happened not only with fun or style features, but also with functional phone settings. A strong motivation for customization was to make the device look and feel "own" by changing the appearance of it to match the user's personal style and to reflect his interaction preferences. Interestingly, Ventä et al [START_REF] Ventä | My phone is part of my soul[END_REF] report a contrary finding regarding the appearance customization of a mobile phone.

In their interview study of 40 mobile phone users, the users stated that they bought a phone with looks they liked, and thus did not want to modify it afterwards.

Furthermore, Tossell et al. [START_REF] Tossell | An empirical analysis of smartphone personalisation: measurement and user variability[END_REF] studied the customization of a smartphone with 24 participants during the first two months of usage. The aim was to examine the relationship between personalization, device usage and usability. The results show a high range of customization, but not across every customization feature measured. For instance, every user acquired a case for their smart phone, but the number of applications installed differed. In general, the results show there are differences between users in the use of customization: not all users customize their smartphones and females and males customize their smartphones di erently. A relation between customization extent and usability was found: those who customized their phones more tended to rate it as more usable. In addition, the users who customized more also used their device for greater periods of time on a broader range of applications.

In a study by Page et al [START_REF] Page | User customization of a word processor[END_REF] the typical customizations made on a word processor were identified. Most users had made changes to their general preferences settings when only few customized the visual appearance of the interface. However, almost all, ninety-two percent of the users, had customized their software in some way. Most of the customization was done to facilitate the participants' work practices, and consequently, users who used the software most did the most customization.

To sum up, users vary a lot on how many features they customize. Features relating to appearance customization are often among the most customized. However, customization is also performed to increase ease of use. Consequently, high level of customization may increase the time of use of the product.

2.3

Reasons and motivations to customize. Customization, by letting users modify their products and services, assumes users are active actors rather than passive consumers. The question why to customize has therefore attracted researchers. For example, Oulasvirta & Blom [START_REF] Oulasvirta | Motivations in personalisation behaviour[END_REF] applied modern theories of motivation to explain user behavior. According to them, analyzing motivations is necessary because they determine the personal relevance that an act of customization carries. However, users differ in how strongly they express different motivations for customization. Oulasvirta & Blom [START_REF] Oulasvirta | Motivations in personalisation behaviour[END_REF] claim there is no special need for customi-zation; rather there are context-independent basic needs that are idiosyncratically manifested motivations related to the use of a product's features. Specifically, users are willing to customize when the product involves and nurtures their psychological needs of autonomy, competence, and relatedness, taps into and extends their interests and preferences, and makes it possible for a user to transform a uniform technology to personally useful and enjoyable tool that can be used to improve and enjoy life and work. Thus, even though there is no need as such for customization, appropriate design of customization features is crucial: "It is through customization features that technology can help the user to align her inner motivational resources with her actions." [1, p.13].

In addition, Marathe & Sundar's [START_REF] Marathe | What drives customization?: control or identity?[END_REF] study on customization of a web portal reveals that customization has deep psychological value when users take time to engage in it and make changes according to their preferences. Specifically, their data show that customization is associated with two psychologically meaningful gratifications: sense of identity and sense of control. Their results demonstrate how customization leads to two distinct patterns of effects: while the effect of customization on sense of control was fully mediated by sense of identity, its effects on sense of identity was only partially mediated by sense of control. This finding leads to the conclusion that "having control is all about being able to express one's identity, but feeling a sense of identity has implications beyond feeling sense of control" [11, p.787]. From an interface design perspective, customization features should therefore offer possibilities for self-representation to express identity. UI designers need to consider what gratification each customization feature will imbue in the user: by fulfilling higher-order needs like enhancing identity and control, designer can create an interface that is an end in itself rather than a means.

2.4

Dispositions to customize and effects of customization. The theory of personalization of appearance (TPA), developed by Blom & Monk [START_REF] Sunikka | Applying text-mining to personalization and customization research literature -Who, what and where?[END_REF] and elaborated by Monk & Blom [START_REF] Monk | A theory of personalisation of appearance: quantitative evaluation of qualitatively derived data[END_REF], indicates the dispositions to personalize and the following effects of personalization on user. The theory has been derived from studies on the personalization of web portals, mobile phones and computer desktops. The dispositions are categorized as the user-, system-or context-dependent and each of them has individual dispositions. For example, user-dependent dispositions are: the frequency of use of the system, ownership of the system, knowledge of personalization and usage time. The system-dependent dispositions relate to the ease and cost of personalization and to the effectiveness of personalization items, i.e. their ability to elicit emotions or improve ease of us. Presence of a disposition may increase the personalization behavior, however, the authors do not explain how many or which of the dispositions are crucial for the personalization to happen. Nevertheless, personalization brings about socio-emotional effects on user. Authors have identified effects that can be divided into Cognitive, Enduring Emotional, Transient Emotional and Control Effects.

Study on customizing a sports watch

An online questionnaire was designed to provide information on the extent and the reasons to customize a sports watch (Figure 1.). In this section, first, the product and measured customization is explained, followed by the description of the online questionnaire, respondents and analysis of the data.

Customizing the sports watch

The product under investigation is a sports watch called Ambit produced by Suunto a Finnish developer and manufacturer of dive computers, heart rate monitors and outdoor sports instruments. The watch has an integrated GPS and the possibility to monitor heart rate. In addition, it has diverse set of specialized outdoor and training functions and is intended for (according to the marketing of the product) "the Outdoor Explorer" [14]. The product is a part of a cross-platform system in which the other part is an online training log site. The site can be used to store and manage exercise logs and to customize the device.

To form an understanding of the extent of customization with this type of device we first identified all the features or items that could be customized on the device. Altogether 28 different features were identified as customizable. However, some features (for example the seven items related to personal settings, e.g. body weight) might not be considered as customization items as such, but rather as essential features to adjust according to the user's characteristics in order for the product to work as intended. Therefore we used the following criteria in the selection of items to be included in the study: the items should concentrate on the top-level customization that are central to the product use, the items should represent the main activities of customization based on previous research [START_REF] Tossell | An empirical analysis of smartphone personalisation: measurement and user variability[END_REF][START_REF] Page | User customization of a word processor[END_REF] and at least some of the items should be customizable both on the device and on the online training log site. Due to the self-report method, it was important that it was reasonable to assume the users were aware of the customization options that were included in the questionnaire. Consequently, we concentrated on features that are explained in the user guide of the product in chapters 'Customizing Your Product' and 'Adjusting Your Settings'. Based on these criteria, ten different measures of customization in three different categories (functionality, general preferences and appearance) were chosen to be included. Top-level customization in this study refers literally to the highest level of customization, namely to the degree whether customization was committed or not on the chosen categories and their main sub-categories. For example, the extent of customization within a default exercise mode (e.g. how many displays and which data fields were customized) is out of the scope of this study.

Customizing the Functionality. Customizing the functionality of the device can only be done on the online training log site. The customization of the functionality of the device happens on two levels: first by choosing what exercise modes are stored on the device and second, by determining what is being measured and shown on the screen during the particular exercise. Consequently, this type of customization defines (part of) the content, and affects the interface of the device when using it during exercising. For example, less exercises stored in the device improves getting access to the functionality, and less screens attached to an exercises decrease the need for scrolling and therefore improves usability.

As a default there are eight different exercise modes stored in the device: alpine skiing, cycling, indoor training, mountaineering, running, trail running, trekking, and other sports (see Figure 2 for a screenshot of customizing the mode for running). The default modes can be used as they are, or they can be customized in the online training log, after which they need to be downloaded on to the device again. In addition, new modes for new exercises can be created from scratch and later modified if needed. In order to measure the top-level customization of functionality we asked if the user had:

Edited displays to default exercise modes Added displays to default exercise modes Deleted default exercise modes Created new exercise modes Edited new exercise modes Customizing General Preferences. Customizing general preferences was included because this type of customization can be performed both on the device and the online training log site. In addition, customizing general preferences has been found to be one of the main customization activities [START_REF] Page | User customization of a word processor[END_REF]. Of the options for general preferences, customizing formats of time, date and units was included in this study. Customizing the time and the date affects how the display looks, and customizing the unit system affects how the data is displayed while exercising. As a default, the device had as a time format 24 h, as a date format dd.mm.yy and the unit system was set to metric. Thus, if the user was satisfied with these formats, no customizing was needed. In the study, the user was asked if he had: Customized time format (12h or 24h) Customized date format (dd.mm.yy or mm/dd/yy) Customized unit system (metric, imperial or advanced) Customizing the Appearance. According to previous research customizing the appearance is an important type of customization and is deeply rooted in the use of certain products [START_REF] Monk | A theory of personalisation of appearance: quantitative evaluation of qualitatively derived data[END_REF]. However, with the device, there are limited possibilities for customization: the display can be inverted from dark to light, and vice versa (both on the device and on the online training log) and the strap can be changed. Customization of the appearance of the device was measure with the two measures:

Invert the display Change of strap

3.2

Customization questionnaire The study was carried out as a part of larger research project investigating long term user experience during six months of product usage. During the research project, each month the respondents answered a questionnaire in English on their product usage and experiences with the product. The customization questionnaire reported in this paper was included in the third survey (third month into the study). Some basic demographic data (e.g. age and nationality) and data on sports activities collected at the recruitment phase of the study are included here. In addition, data on exercise habits, product usage and satisfaction with the product collected in each survey are combined with the customization data.

The 21 questions related to customization consisted of both closed and open-ended question, and were on the last page of the questionnaire. At top of the page, a description of customization was given. Multiple choice questions were used to find out about the extent of customization: the respondents were asked to mark from the list of ten customization items all the ones they had used during the total time of product usage. Closed-ended questions with a 7-point interval scaling (1-7; 7 signifying strong agreement) were used to evaluate the importance of customization, the ease of customization and the effects of customization (e.g. product being more useful and personal after customization). Open-ended questions were used to probe about the knowledge of customization of the product before taking it into use and the reasons for customizing the product. In addition, the respondents were encouraged to comment freely after questions.

Respondents

The respondents for the six month long study were selected among the customers who responded positively to the e-mail invitation to take part in the study by answering a short questionnaire with basic demographic, product purchase and usage questions. The invitation was sent to 521 registered owners of the product of which 190 (36%) expressed their interest to take part. 121 were chosen to take part based on three criteria: 1. Short usage time of the product; 2. Nationality; and 3. First come first served. As an incentive to take part, a respondent would receive a product of Suunto worth up to 269 USD after completing all six surveys.At the time of the data collection for this paper (third survey), the number of respondents had dropped to 110 (21 % of the whole sample getting an invitation). A further ten respondents and their responses were removed from the analysis due to missing data leaving the sample size to 100 respondents.

3.4

Analysis. For the quantitative data, nonparametric tests were selected due to the nonparametric (distribution-free) nature of the gathered data. The CHI Square was used in pairwise comparisons of categorical variables and Spearman's was used in calculating correlations. A content analysis was performed to analyze the participants' descriptions of their main reasons for customizing the device. In the analysis, the basic needs of autonomy, competence and relatedness, and the motivations relating to them were used as the guiding framework [START_REF] Oulasvirta | Motivations in personalisation behaviour[END_REF]. Sports watch usage. The respondents were asked how often they use the device as a daily watch and in exercising (Table 1). Although the device is mainly targeted for use during different exercising activities, over half of the respondents (56) use it daily as a daily watch. However, diverse use of the device is common: majority of the respondent (67 respondents) falls under a usage profile in which the watch is used at least several times a week both in exercising and as a daily watch. 16 participants use the device daily both as a time piece and in exercising. On the other hand, there are respondents who tend to use the watch more specifically for exercising: 21 respondents, who use the watch several times a week in exercising, use it only up to once a week as a daily watch. In addition, there are 8 respondents who mainly use the watch as a daily watch and only up to once a week in exercising. Furthermore, 4 respondents use the watch rarely in either use on a weekly basis.

4.2

The Extent of Customization Table 2 gives the percentages of the 100 respondents that reported having customized that particular item. The most popular item to be customized was to invert the display. Almost as popular was the functionality related customization of editing displays to default exercise modes. However, overall, the rate of customizing was high with every item with the exception of customizing the appearance by changing the strap which was done by only one respondent. Customization score. The customization score represents the number of the customization features the respondents reported having used. On average, the respondents had used 5.6 (STD 2.2, median 6, mode 7) of the ten customization features measured in this study. The high mean score indicates relatively comprehensive use of the features available, and may suggest general interest to customize in this context. However, the wide range of customization (range 0 -9 items) and high variability across items measured among the respondents suggests there are differences in customization behavior. Grouping the respondent based on the number of items customized show there are four main groups (Table 3) that can be divided to low customization group and high customization group with the average customization score as a divider.

Table 3. Groups of respondents based on the number of items customized

Customization group Number of items customized Frequency

Low customization 0-3 19

4-5 27

High customization 6-7 34

8-9 20

Earlier studies have found differences in customization extent, for example, originating from gender [START_REF] Tossell | An empirical analysis of smartphone personalisation: measurement and user variability[END_REF] and the presence of dispositions [START_REF] Blom | Theory of personalization of appearance: why users personalize their pcs and mobile phones[END_REF]. The effect of gender was impossible to measure in this study due to small amount of females in the sample. However, user related dispositions 'Frequency of Use of Product' and 'Knowledge of Customization', and system related disposition 'Ease of Customization' were taken into account in this study. A Chi Square test was performed to determine if there was a difference between usage frequency of the device in exercising and use as a daily watch and customization score (low customization/high customization group). The test indicated a significant difference with usage in exercising ( 2 = 7.19, df = 2, p <.05). However, the test failed to indicate a significant difference with usage as a daily watch ( 2 = 2.74, df = 3, p= .433). The results indicate that use of the device in exercising may urge customization. Furthermore, a Chi square test was performed to determine if there was a difference between knowledge of customization and customization score. The respondents were categorized based on their knowledge of customization in three groups: 'Being able to customize was one of the purchase decisions', 'I knew about customization before purchase' and 'I did not know about customization before purchase'. However, the test failed to indicate a significant difference ( 2 = 2.72, df = 4, p= 0.605). Correlation (Spearman's ) was calculated to study the relationships between the ease of customizing the functionality and the customization score. There was a weak correlation between customizing the functionality and customization score (Spearman's r=.209, p<.05). This correlation indicates that there is a relation between the ease of customization of exercise modes and customization behavior, but it is impossible to say if ease of customization caused more customization. It may as well be the opposite: by customizing more the respondents may have enhanced skills in customizing and therefore it is perceived as easy.

In the following paragraphs the use of each of the different types of customization will be discussed separately.

Functionality-based customization. Customization of functionality was measured by three items relating default exercise modes (editing displays, adding displays and deleting modes), and two items relating to new modes (creating and editing).

The possibility to customize the default exercise modes was used extensively: 87 respondents had utilized at least one of the customization options provided. 50 respondents had used all the three options given, 21 had edited and added displays, 6 had only edited displays, 5 had edited displays and deleted modes, 2 had deleted modes, 2 had only added displays and one had only added displays and deleted modes. 68 respondents reported having used the customization option to create a new exercise mode, and 48 had also edited the new mode. 38 respondents had customized all three default modes and created new modes. It was more popular to customize the default exercise modes than to create their own. A Chi Square test was performed to determine if there was a difference between the usage frequency of the device in exercising and the use of functionality customization items. The test with create new mode indicated a significant difference ( 2(2) = 6.16, p <.05) suggesting that the respondent who use the device more in exercising create more new exercise modes.

General preferences. Formats were also actively customized: altogether 71 respondents had customized at least one of the formats. To be precise, 35 respondents had customized all three formats; 27 respondents had customized just one of the formats (time by 13 respondents, unit by 11 and date by three), and nine respondents had customized combination of two formats. Altogether eight different combinations to customize (or not to customize) the three formats were found.

There are different conventional ways to present formats in different countries and we expected respondents from countries where the default formats are commonly used not to customize them. A cultural analysis was performed due to the unexpected high number of respondents who customized the formats. Among the 19 different nationalities there were 10 from countries (origins of 51 respondents) in where the same as the default date, time and unit formats set on the device are commonly used. In eight cultures (origins of 37 respondents) partly same as default formats are used: for example in Australia the dd.mm.yy style of date format and metric system is used, but for the time, the 12h format is used. In some countries, like Canada and Philippines (origins of 7 respondents), different notations, especially with regard to date and time, are used concurrently depending on the language of the citizen. In contrast, in US (12 respondents) none of the default formats are used suggesting a need for customization of formats for American respondents in our study.

Based on the clarification of the conventions in different countries, we investigated the customization of each format separately per respondent by comparing the respondent's nationality to the reported customization of the formats. The base line was the assumption that a respondent would use formats customary to his culture. This analysis aimed at investigating the possible effect of culture on the reported customization of formats by revealing frequencies of respondents who 1) customized according to expectations based on cultural notation and 2) customized contrary to cultural notation. Some respondents were left out from the analysis due to uncertainty of commonly used notations in their countries of origin: British and Canadian respondents (14) were left out from the analysis of time, Canadian, Filipino, and South African respondents [START_REF] Page | User customization of a word processor[END_REF] were left out from the analysis of date, and British were left out from the analysis of units. The results indicate individual preferences differ from cultural conventions with approximately third of the respondents. The difference from cultural conventions is further highlighted when investigating the customization of the formats with the biggest nationality groups further. For example, five out of twelve of the Dutch respondents had done some customization: one had customized the date and time format, one the date and unit, two had customized the unit and one the time. Further, five out of ten of the Finnish respondents had customized all the formats, one had changed the time and one the date. This leaves only three who had kept the default formats that are the common notation in Finland. In addition, half of the American respondents (6/12) had customized all formats, two the date and time, one time and date, one time and unit, one the date, and one had not customized any.

To understand the reason for customizing the general preferences contrary to cultural conventions, we looked into the responses to the open-ended question asking reasons for customizing the device (Analyzed more thoroughly in section 4.5). Since the question was general, only nine respondents specifically mentioned reasons to customizing the formats. Nevertheless, the responses show that convenience in a context or in use situation and willingness to experience and try out new things may trigger the customization of formats: "I change the unit system for pacing a friend during a 100miler in the USA. I used the imperial system instead of the metric so we didn't have to do the conversion all the times" (ID64, Canadian)"; "I liked trying different formats and using US formats vs European (…)" (ID43, American).

Customization of Appearance. There were only two possibilities to customize the appearance of the device: by changing the strap and by inverting the display from light to dark or vice versa. The latter was the most often customized item.

Only one respondent had changed the strap. Analysis of the free text comments showed that many respondents were not aware of the possibility to change the strap but would be interested in it. On the other hand, there was couple of respondents who were not interested in customizing the appearance at all: "No need to customize look. This one is perfect." (ID91).

4.3

Reasons to customize

In the analysis of qualitative data on reasons to customize, two responses were excluded due to answers relating more to the need for new customized features than reasons to customize. The analysis was based on Oulasvirta & Blom [START_REF] Oulasvirta | Motivations in personalisation behaviour[END_REF] who suggest the Self-Determination Theory (STD) [START_REF] Deci | The ''what'' and ''why'' of goal pursuits: Human needs and the self-determination of behaviour[END_REF] as a framework to understand customization. The reasons were categorized into the motivations relating to the attainment of three basic needs, autonomy, competence and relatedness.

Four respondents claimed they have not engaged in customization (yet) or that they are happy with their settings. These four respondents were on the low customization group (0-3 items customized). The responses from the remaining 94 respondents gave 157 reasons to customize: each reason given was categorized and thus, the average amount of reasons per respondents was 1.6. The results are presented below first with Figure 3 presenting frequencies of the reasons as motivation categories. After that the main findings on each motivation is described separately with quotes from the respondents. A category "Looks" was included in the analysis outside the analysis framework since responses relating to the improving the appearance did not fit to any of the categories. Autonomy. The given reasons to customize were clearly most often related to control and the motivation relating to autonomy. This was highlighted by the use of wordings like "I want", "I need", "I like to have". The feeling of control was often related to ease-of-use and/or effectiveness of use. In addition, respondents often described the specific needs in relation to their activities: the importance to see the relevant information easily in a glance and without the hassle of going through different screens. At the same time, they recognized customization as "mandatory" in order to make the device personal. Some respondents engaged in customization just for fun or to try out. Competence. Motivations to customize relating to the basic need of competence are to do with acquiring skills, differentiating oneself by preferences and interests and engaging in action. Often the competence motivations were mentioned along with control and the benefits of customization was acknowledged. In some responses the ability to customize or to learn from the act of customization was seen as beneficial to the individual. Relatedness and the Looks. Customization of the device was clearly not driven by motivations of emotional or identity expression. There were many who claimed the reason for customization was to make the information provided by the device more personal but only two respondents claimed they customized the device (and not only the information) to make it their own. Three respondents specifically said they had changed the display color to improve the looks although most respondents had used the feature.

"I have changed to the dark display because it looks better. I have customized the exercise mode to also allow me to measure other activities and display I like to have while I am performing said exercise. I set the time format to military time (24 hrs) which is my preferred way to tell time." (ID77) "Needed to customize the watch to make it feel more personal, to make it feel like it belongs to me. To make the intepretation of information from the watch easier." (ID106)

Summary. Both the low and high customization groups expressed for the most part similar reasons to customize. The main differences with them were that in the high customization group's responses control appeared more, whereas the low customization group mentioned motivations relating exploration more often.

4.4

Importance and effects of customization. Importance of customization and effects of customization (customization makes the product more personal and useful) was measured by asking an agreement to corresponding statements with a 7-point scale (1-7; 7 signifying strong agreement). In addition, the respondents had possibility leave comments on a free text field. Correlations (Spearman's ) were calculated to study the relationships between the state-ments and customization score. Table 6 presents the basic descriptives and correlations with customization score. Generally, the respondents showed high agreement with all statements. Regarding the importance of customization, the results suggest it is more important for the respondents to customize the exercise modes than the basic functionality or appearance. In addition, the ability of customization to make the product more useful was appreciated:

"I like to customize my gadgets for my preference. It's like new every time I customize it." (ID101)

There was a positive correlation between all statements and customization score. This correlation indicates that respondents who expressed stronger agreement with the statements had customized the product more.

4.5

Satisfaction. Satisfaction with the device was measured with a simple question: "How satisfied are you with your Suunto Ambit?" with a 7 -point scale (1-7; 7 signifying strong satisfaction). The respondents reported very high satisfaction with an average score of 5.97 (STD 1.2, median 6, mode 6). Correlation (Spearman's ) was calculated to study the relationships between satisfaction and customization score but no correlation between the measures was found (Spearman's r=-.013).

Discussion

The current results show the users of a sports watch customize their device extensively albeit a high customization group and a low customization group could be distinguished. There was only one respondent who had not customized his device at all and only one customization option (appearance-related: strap change) was used by only one respondent. However, little use seemed to be due to unawareness of the respondents about the option, and not because it was not appreciated. Customization of appearance (invert the display) was the most often customized item followed by the four main items of functionality customization. Functionality-based customization was rated as the most important, and customization was seen as an instrument that makes the product more useful. The respondents seemed to have practical reasons for customization: those who used the device more in exercising had also customized it more extensively. However, we cannot say if more customization resulted in more use (in exercising), a phenomenon seen with smartphones [START_REF] Tossell | An empirical analysis of smartphone personalisation: measurement and user variability[END_REF], rather, the product may be contrasted to a work tool: in Page et al [START_REF] Page | User customization of a word processor[END_REF] study on a word processor persons who used the software most, had customized most. This was also the case here: the respondents who used the device more in exercising, had customized it more. However, the finding does not allow proposing a cause-and-effect relationship between the variables. Rather, it may point to the fact that using the device more in exercising, the user becomes more aware of his needs with regard to measuring his performance and capabilities of operating the device during the particular exercise (e.g. contextual factors). Therefore, more needs for customization arouses, and more customization on the device is likely to be performed. The sport a user does may have an effect on customization needs.

In previous research the emphasis has often been on the customization of the appearance (e.g [START_REF] Blom | Theory of personalization of appearance: why users personalize their pcs and mobile phones[END_REF][START_REF] Monk | A theory of personalisation of appearance: quantitative evaluation of qualitatively derived data[END_REF]) because customization of appearance is the way to make the device look and feel "own" [START_REF] Häkkila | Personal customisation of mobile phones: a case study[END_REF]. The results of this study suggest that customization of appearance is not the only condition to feel that a product is personal. Being able to customize the main functionality of the products, to better fit it to the individual needs (in an activity important for the individual), can bring about the feeling of the product being personal. In fact, the findings by Marathe & Sundar [START_REF] Marathe | What drives customization?: control or identity?[END_REF] on the effect of customization on sense of control seem to fit here: having control is a way to express one's identity. Furthermore, it the results indicate that the respondents got a product with looks they liked and thus, customization of appearance was not so important at least in order to express identity.

Control was the main motivation to customize with other motivations relating to autonomy following. No major differences between the respondents in different customization groups were found, but high customizers expressed some more control, whereas low customizers expressed more motivations relating to exploration. Overall, the results suggest that customization can be explained by the three basic needs, autonomy, competence and relatedness, with motivations in this context deriving mostly from the need for autonomy. Customization features are valued due to the sense of control the user has by having the tool to adapt the product according to own preferences, wants and needs. This sense of control was seen as a reason to customize in every customization type, not only in functionality customization.

The respondents who did not customize or customized minimally raise the question on their reasons for not customizing. In line with the results from Tossell et al. [START_REF] Tossell | An empirical analysis of smartphone personalisation: measurement and user variability[END_REF], it was learned that non-customizers have reasons for their behavior: there was not a need for it, the options were not suitable or the user was not aware of the possibilities. We feel the reasons for non-customizing may point to directions to further develop the customization features or, at least, improve the information about them.

Finally, we did not find correlation between satisfaction and customization extent despite it seems logical. A reason for this may be the overall high satisfaction with the product, and the insight that a user does not need to customize extensively to be satisfied with a product as long as his personal needs will be fulfilled and he can feel to be in control. Furthermore, a small matter, like the inversion of display color may be enough for a pleasurable experience.

Design Implications. Customization is a product feature that enables differentiation from competitors. However, available options should be easily found and recognized by the users or they may be unused despite their interest in using them. It seems there cannot be too many options: the more the better. The user should have the full control in deciding what is customized, but recommendations, for example, relating to contextual factors might be in order.

Limitations and future studies. There are certain limitations with this study. First, as the data was collected with an online questionnaire we cannot be sure how seriously the respondents took their reporting task, and since no observation was possible, the results are solely based on self-reports. In addition, it is not known if the respondents fully understood the concept of customization. On the other hand, the method seems appropriate for studying the top-level customization, and respondents with missing data were excluded from the analysis. Another limitation relates to the respondents that were drawn from the company's customer base. A customer interacting with a company might avoid giving negative feedback especially in a study with an incentive. However, the respondents were informed that the study is a research project conducted in a university and for example, all the communication with the respondents was from the university. In addition, reaching the respondents would have been quite difficult without the help from the company. Finally, the study reviewed the top-level customization of a sports watch: if more features were included to be measured, there might be more variety in the customization profiles.

In future studies, the aim will be to explore the true effect of customization on satisfaction and user experience by collecting data with repeated measures from the first usage (before any customization is performed) into couple of months use. With repeated measures the change in satisfaction and user experience could be compared to the extent of customization. At the same time, the process of customization could be explored: how often is customization performed and why, are the customized features actually used, and what kinds of effects arise from the process. Similarly, the preferred ways to do customization could be investigated. Another point of direction could be to study customization of a couple of products from the same user to explore the customization behavior and gain understanding in customization and motivation to customize in different context.

Conclusions

This study gives insight into customization in a new context. Previous studies have for the most part concentrated on the customization of appearance; this study introduces functional customization as an important part of product experience. This study explores the use of customization features of sports watch in order to assess the extent of customization, and identify reasons for customization in this context. Survey data from 100 users of a sports watch were analyzed to understand how they use the different customization features: general preferences, functionality and appearance. The findings show that in this context customization was extensive, but a high and a low customization groups were found. Despite the differences in customization extent, the users state similar reasons for customization: control, ease-of-use, increased effectiveness, and better fit to personal preferences. The motivation to customize in this context is for the most part related to autonomy: to the sense of control the user has by having the tool to adapt the product according to own preferences, wants and needs.

Fig. 1 .

 1 Fig. 1. One the left, the two different variants of the sports watch: the black with dark display and the silver with light display. On the right, a screen capture of the customization of running mode on the online training log

Fig. 2 .

 2 Fig. 2.Reasons to customize categorized in motivation types relating to autonomy (black), competence (grey) and relatedness (white). The graph presents number of reasons given by the respondents for each motivation type

"

  No company could make a watch which suits everybody, so customizing is mandatory for me. Nobody other than me knows what I want." (ID21) "The main reason is that I want to decide what information is important to me while I exercise. I also want to control what buttons and how often I have to push a button in order to get the information I need." (ID54) "Just to try out how it works, to have kayaking in the menu, and for having specific details on the watch display for different exercises to make it easier to use."(ID36)

4 Results 4.1 Characterizing the user Demographic information

  Running was the favorite sport with 47 replies (includes 27 replies mentioning trail running specifically). Other top three sport activities were hiking and biking (off road, mountain or road) both with 14 mentions and skiing (off-piste, alpine or Nordic pole) with 7 mentions. On average, the participants exercise 4.3 times per week (STD 2.08, median 4, mode 3,).

. The 100 respondents consisted of 93 males and 7 females, and their age varied between 22 and 64 years, with the mean age being 41 years (two modes: 37 and 45 years). 49 respondents had owned the device for three months and 51 respondents for four months. Over half of the respondents were from Europe (58 respondents), but the sample consisted nationalities from almost every continent: North America 18, Oceania 11, Asia 10, and (South) Africa 3. There were 17 different nationalities among the respondents. The four biggest nationality groups were Dutch with 13 respondents, Americans with 12 respondents, Finnish with 10 respondents and Australians with 9 respondents. 34 respondents have English as their mother tongue. Sport activities. Since the product is targeted for training and especially outdoors activities, we were interested in what activities the respondents engage in. From the list of 18 types of sports (with an open text for 'other' option), the respondent marked each sport he does. The respondents are active: on average they engage in seven different sports (range 2 -16, mode 6), and altogether 46 different sports were mentioned. The most often mentioned sports were hiking (81), road running (70), trail running (60), road bicycling (60), going to the gym (49) and mountain biking (42). Thefavorite sport was asked with an open-ended question.

Table 1 .

 1 Frequencies of the respondets using the watch in exercising and as a daily watch.

			Using the watch in exercising
			Less than once week or not at all	Once a week
		Not at all		2	3		5
	Using the	Less than once week or not at all	1		7	1	9
	watch as a	Once a week		1	10		11
	daily watch	Several times a week		1	13	5	19
		Daily	2	5	33	16	56
		Total	3	9	66	22	100

Table 2 .

 2 The percentage of the respondents who customized the particular item

	Customization type	Item	Percentage
	Appearance	Invert the display	83 %
	Functionality	Edit displays to default exercise modes	82 %
	Functionality	Add displays to default exercise modes	74 %
	Functionality	Create new exercise modes	68 %
	Functionality	Delete default exercise modes	58 %
	General preferences	Customizing Time format (12h or 24h)	56 %
	General preferences	Customizing Unit system (metric, imperial or advanced)	51 %
	Functionality	Edit new exercise modes	48 %
	General preferences	Customizing Date format (dd.mm.yy or mm/dd/yy)	43 %
	Appearance	Change of strap	1 %

Table 4 .

 4 Customization behavior based on cultural notations

		Date (n=90)	Time (n=86)	Units (n=92):
	According to expectations	62%,	65%,	55%,
	Against expectations	38%	35%	46%

Table 5 .

 5 Basic descriptives and correlations of customization score with statements relating to effects of customization

	Statement	Descriptives	Cust. score
	Being able to customize the exercise modes is important to me.	6.7 (STD.63, median 7, mode 7)	.340**
	Being able to customize the formats of time, date and units is important to me.	5.9 (STD1.8, median 6, mode 6)	.328**
	Being able to customize the looks of the product is important to me.	5.1 (STD1.7, median 5, mode 7)	.228*
	Being able to customize makes the product more useful.	6.7 (STD.68, median 7, mode 7)	.337**
	I feel the product is more personal after customi-zation.	6.5 (STD.80, median 7, mode 7)	.347**
	**. Correlation is significant at the 0.01 level (2-tailed), *. Correlation is significant at the 0.05 level (2-tailed).

Acknowledgments. The author thanks Suunto and especially Tiina Taskinen for cooperation and enabling of the study, researcher Tiina Koponen (Human-Centered Technology, Tampere University of Technology) for her invaluable contributions to help carrying out this study and assistant professors Timo Partala and Satu Jumisko-Pyykkö (Human-Centered Technology, Tampere University of Technology), for their comments on the manuscript. This research was supported by the Finnish Doctoral Program in User-Centered Information Technology (UCIT) and the Finnish Funding Agency for Technology and Innovation (Tekes) through the project DELUX.


Paolo Burzacca
email: paolo.burzacca@isti.cnr.it

Fabio Paternò
email: fabio.paterno@isti.cnr.it

Analysis and Visualization of Interactions with Mobile Web Applications

Keywords: Tools for Remote Evaluation, Web Applications, Mobile HCI

We present a novel solution for intelligent analysis and visualization of user interactions with Web applications through mobile devices in order to help identify usability issues. The proposed tool is also able to support comparison of optimal use with actual user interactions. We also report on an example application of our tool to the evaluation of a real mobile Web site.

Introduction

Logging tools for supporting usability evaluation have long been investigated in the context of desktop access. However, such tools cannot be simply re-proposed as they are for mobile devices, given their specific characteristics in terms of relevant events and usability issues. Indeed, mobile devices are becoming ever richer in terms of sensors, such as accelerometers, GPS, and so on. In addition, because of the limited screen size mobile devices have specific usability problems, such as tedious activities in zooming in and out for viewing the desired piece of information or touch/based interactions that select the wrong elements [START_REF] Nebeling | W3Touch: Metrics-based Web Content Adaptation for Touch[END_REF].

Remote evaluation supports the analysis of the user behavior in real contexts of use, and this is important with mobile applications that can be accessed in varying contexts. Various tools for capturing logs of user interactions have been proposed but theye were limited in various aspects. Thus, there is a need for improvements in tools able to support remote usability evaluation, in particular when mobile devices are considered. For example, WebQuilt [START_REF] Waterson | In the lab and out in the wild: remote web usability testing for mobile devices[END_REF] only performed proxy-based logging and, thus, it was not able to gather detailed information regarding user interactions and the surrounding environment. Other approaches exploiting client-based logging [START_REF] Carta | Support for Remote Usability Evaluation of Web Mobile Applications[END_REF] [START_REF] Santana | Summarizing observational client-side data to reveal web usage patterns[END_REF] provided reports of the data collected not easy to interpret. The evaluation of the interactions with mobile application by comparing task models with the logs associated with real use was investigated in [START_REF] Santana | Summarizing observational client-side data to reveal web usage patterns[END_REF]. In the tool that we present here we propose a novel approach in which the logs of the actual use are compared with an optimal log created by a user interface expert.

The Environment for Remote Evaluation

The proposed environment aims to support remote evaluation of Web applications accessed through any type of device. In this paper we focus on the specific aspects related to mobile access. In order to perform a usability evaluation there are three main phases: preparation, during which the evaluators define the tasks that should be performed during the test and provide examples of optimal performance of such tasks; test, during which the users access the application from any device through a proxy server that includes the logging scripts and stores the logs in the backend; and the final usability analysis, which is based on the information collected beforehand and exploits visualizations that facilitate the identification of potential usability problems.

The usability server includes a proxy through which users should access the Web applications. Such logging can detect any type of event, even events defined by the evaluators. The backend part supports functionalities able to provide useful visualizations of logs through interactive, configurable timelines, and intelligent comparison of actual behaviour with optimal interaction sequences.

One of the activities to carry out during the preparation phase of a user test by the evaluators is the creation of the task list. For each task the evaluator has to provide the name, description, if it has to be started from a specific page then its URL should be specified, whether it can be skipped, whether its performance depends on some other task. For the interaction with end users the choice was to interfere as less as possible with the access to the applications. Thus, the only interaction is given by the task panel, which provides some basic instructions at the beginning of the session, and is used to indicate the start and the end of a task performance, and the next task to accomplish. Thus, the user starts the test through the public user interface, and the proxy includes the control panel, which contains instructions regarding the task, and it allows users to start/finish/jump the task, with minimal intrusiveness.

In our environment the logging is performed through an infrastructure that has been designed for this purpose. We use a log model in which each event is defined by <timestamp, element, id, event, which, extra>, timestamp indicates when the event occurred; element is the DOM element associated to the event; id is the unique identifier of the element; event indicates the event type (e.g. click, touchstart, scroll,...); which indicates the value of the event object (e.g. what character has been entered when pressing a key or what mouse button has been pressed); extra is used to provide additional information, when necessary, such as URL page and window size for the on load page event, GPS coordinates for GPS events, screen coordinates for mousemove or click events. The events recorded include: all the standard events, touch events, events related to accelerometer and GPS, DOM Mutation events, basic semantic events (pageview, starttask, closetask, …). We also manage semantic events that are used in our environment in order to provide more information that can be useful for the evaluators. Thus, we have a set of basic semantic events mainly associated with the task panel access or the task performance. In addition, it is possible to define custom semantic events, which are composition of basic events or standard events on specific parameters with specific event names.

3

The Timelines and Other Visual Information

Timelines are used to represent information gathered from the logs. Previous solutions [START_REF] Carta | Support for Remote Usability Evaluation of Web Mobile Applications[END_REF] have provided rather static and limited representations of such timelines, we have thus designed new solutions to represent and manipulate them.

The tool allows evaluators to access the list of available timelines from a given user test ordered by time of the corresponding log files. The first timeline is that generated by the evaluator to store an optimal performance of the given task (Figure 1 shows an example), and it is used as a comparison reference for assessing the performance of the various users, and identifying possible usability problems. Each timeline expands temporally from left to right. For each timeline some useful data are shown: an identifier, an incremental number associated with the corresponding task, when the corresponding log was detected, and the overall duration of the user session. In addition, some information regarding the device used is provided. For this purpose, during the user test the environment takes the user agent and uses it to retrieve more detailed information from a Device Description Repository (we have used WURFL1 ).

Our environment provides the evaluator with various interactive functionalities useful to ease the comparison of logs and their analysis. The timeline visualization is completely dynamic and interactive. All timelines and events can be selected in order to apply specific operations to them. The initial representation of the timeline shows all the events in the log. This can be confusing and complicate the analysis because not all the events may be relevant. Thus, the tool provides evaluators with the possibility of interactively filtering the events through a panel with one check-box for each event category (e.g. form events, keyboard events, touch events, ..).

The events shown are represented through a label and a coloured small circle. The timelines also include some vertical black lines among the events indicating when a page change has occurred. When an event is selected then the corresponding information (e.g. when it occurred, in which element it occurred, ..) is shown. It is also possible to search for a given event, in this case only the occurrences of such event are shown. In case multiple timelines are shown then they are lined according to the first occurrence of the searched event. In order to facilitate the comparison of various logs the tool allows the evaluator to line up the timelines according to when users started to navigate on a given page as well (Figure 1 shows an example). This facilitates the comparison of how different users interacted within the same page. The tool has a zoom feature for adjusting the time scale, thereby allowing the evaluator to expand or contract the events in the timelines. Indeed, it often happens to find many events grouped in very small time intervals, and thus they have overlapping, confusing representations, which can be improved through this feature.

While the timelines provide an effective interactive dynamic representations of the users' sessions, we also introduced an event analyzer with the goal to provide an overall summarizing representation of what happened during the test. The evaluator can select an event category and the tool shows a list of bar charts showing the number of occurrences of such events for each session. The tool also provides the possibility of more explicit comparisons among various sessions. For example, it is possible to compare through bar charts the navigation time across the various pages that have been accessed by the considered sessions.

In addition to time-related information, another useful piece of information is the path followed by the user during the navigation. It is not immediate and intuitive to extract such information from the timelines. Thus, our environment also provides the possibility to show visual storyboards, which also easily highlight possible cycles during the navigation. As you can see in Figure 2, each page is represented by a rectangle with an identifier, the visit time, and an arrow indicating the next page accessed.

Fig. 2. An example representation provided by the visual storyboard

If a page is visited multiple times then the time is the sum of all the visit times. The arrows are annotated with numbers indicating their temporal order. The rectangles indicating the pages navigated have different colours depending whether they have been accessed in all the considered sessions or not. For each page that can be analysed it is also possible to show its screen dump captured during the user session, graphically annotated in order to indicate where the user interactions occurred.

Automatic Log Analysis

In our environment we have also investigated the possibility of providing more automatic support in the log analysis, still through comparison of the user logs with the optimal log initially provided by the evaluator. For this purpose, we have applied the Sequence Alignment Method (SAM) to the comparison of logs of user interactions. Previously, it has been applied to identify navigation patterns in Web applications [START_REF] Hay | Mining Navigation Patterns Using a Sequence Alignment Method[END_REF]. We have investigated how to exploit it in order to help identifying potential usability problems. In general, the SAM approach aims to calculate the differences among two sequences of elements. The difference between sequences is represented by the number of operations necessary to make them equal, where each operation has a different weight, which depends on its importance. The operations available for equalizing two sequences are reordering, insertion, and deletion.

In our logs we have information related to both pages accessed and events generated. Thus, when we apply the SAM analysis we distinguish the distance in terms of both types of elements. Actually, in the events we also distinguish between custom semantic events and the others. In the end, the distance between two logs is calculated by summing the distance of these three sequences, where the composing distances have different weights to reflect their different importance for the usability analysis. Indeed, the differences in pages accessed is more important, since if the users have visited pages different from those accessed in the optimal session, then they have probably not accomplished their task correctly. For the custom semantic events, most analysis is limited to check whether they occur in the sequence considered. For the other events they are considered the same if they occur in the same page and on the same user interface element. The weights associated with the elements compared and the type of SAM operation play an important role in determining the final result. Since it is difficult, and probably not possible, to find general weights that always provide the most meaningful results, we decided to allow evaluators to customize them. For example, in the page sequences comparison an evaluator should consider the application type considered and its navigation model: if the task can be accomplished through different paths within the Web application then the weights for the page sequences differences should be low because some differences are probably not indicating any particular problem. The tool also provides some useful information regarding the differences among the sequences. For example, in the case of the page sequences the tool also indicates the pages that differ in the two sessions. As Figure 3 shows, for such pages it also indicates the page previously accessed, which is useful to allow the evaluator to understand from which page the user has taken the wrong path.

An Example Application

In order to validate our environment we considered an example application, the mobile version of an airline Web site 2 . We first asked some end users to test it through our logging infrastructure and report on its usability issues, then we asked some evaluators to use the information provided by our tool to identify the application usability problems in order to check whether they would have found similar problems.

The application was accessed remotely by the users without any direct support from the evaluators. Users only received at the beginning some information by email about the purpose of the test and how to start it. Users were free to choose the mobile device used for the test and the exact time and location to carry it out.

The test was carried out by seven users, the average age was 32, and they had not used our tool beforehand. The test consisted in performing five tasks chosen in such a way to consider the various aspects characterising Web access. For each task we defined some custom semantic events to have more control in the analysis of the user logs. The first task was to search for a flight from Paris to London with intermediate stop in Frankfurt for a precise day in economy basic fare. In this way the users had to choose among various options and go through various steps to complete the task. We defined a custom semantic event with the selection of the One Way option to better check that users selected it. The second task was to find information about the lounge in Frankfurt. Here the most difficult part was to find the page regarding lounges. Actually, for this purpose two different paths across the Web site were possible, and we included two custom semantic events to easily identify which one was taken. The third task was to find the time for a flight from Munich to Cracow in a given date. The flight should have been direct, and the last available on the indicated date. Also in this case we introduced a couple of custom semantic events. The fourth task was to find how to reach the Frankfurt airport from Strasburg by bus. In this task there was no form to fill in. The fifth task was to find information about the Boeing 737-300. We introduced one custom semantic event to check the path followed.

Regarding the first task, some users complained that the Web site had the one way option clearly visible and highlighted, thus erroneously leading them to think that it was selected, and they only realized that this was not the case when the application asked them to select the return date. In the second task one user indicated a problem with a pull-down menu to select the class because it was displayed partly off the screen. In the third task the users had some difficulties in specifying all the options requested. For the fourth task the only problem seemed to be the long navigation required to reach the page to complete it. Similar issues were reported also for the fifth task in which some users found complications because of a misleading link label.

Regarding the use of our environment for the test, the users generally appreciated its ease of use and lack of intrusiveness. They only found that the automatic creation of the screendump at each page change caused some delay in the interaction. Some users suggested the possibility of creating more detailed user profiles, which can be considered during the analysis phase.

Then, we compared the direct user feedback regarding the mobile application with results obtained with the support of our tool. We thus asked a group with knowledge in usability evaluation to use it in order to identify possible usability problems. We provided them with a short tutorial regarding the tool. We then briefly explained how its various features can be exploited. Then, the evaluators considered each task and the associated user logs in order to identify possible usability problems. We involved six people (three males and three females), average age was 34, all of them with experience in usability evaluation for both desktop and mobile applications, mainly through laboratory user tests or feedback through interviews, questionnaires, and focus groups, thus with little experience in remote usability evaluation, even if they found the approach useful and interesting. They had never used our tool beforehand.

In general, the evaluators found the tool user interface clear and well-structured. They liked the timelines management and the possibility of searching events and pages in them. The evaluators considered how all the users carried out each task through the information provided by the tool. For the first task (Find flight from Paris to London) they soon noticed some long session durations. The occurrence of the second custom semantic event revealed some issues, since it often appeared consistently later than in the optimal session. Likewise, the last custom semantic event associated with the correct flight selection often occurred in an anomalous manner. Some evaluators used the possibility of lining up the timelines according to the pages accessed in the optimal session. This was useful to confirm that in the access to the first two pages the sessions were similar. However, at the page related to the flight selection, the users' behaviour became substantially different. For example, while in the optimal selection the one way option was immediately selected, in some user sessions the user triggered various keyboard events beforehand. This implies that such users made a search without selecting the one way option and then got the request from the application to indicate the date for the return flight. In this case, the involved users either went back to the previous page or stopped their activities for a while. Then, in the end the one way selection event occurred, indicating that they eventually understood the mistake.

In the analysis of the second task (Find information about the lounge in Frankfurt) the evaluators noticed that the users all started from the same page and finished at the right one, but the intermediate pages differed. Indeed, when they searched for the custom semantic event associated with the loading of the page Miles More, they noticed that only one user passed through it. Such differences were well highlighted by the storyboard. The usability issue was that there were two possible ways to accomplish the task, and the shorter was not immediately apparent to the users. Indeed, the path followed in the optimal session requires a link selection (Miles & More) to access information about the lounges, and this was not intuitive.

In the analysis of the third task (Find the flight from Munich to Cracow) the evaluators' analyses focused on the search for the occurrence of the Timetable Page loaded event. Only one user missed that event. Then, the evaluators compared the time taken from when the corresponding page was loaded to when that specific event occurred. For this purpose, some of them combined the search for pages with that for events so as to filter the events to display only the relevant one and align the display according to the flight timetable page in order to compare how long users visited that page. In order to analyse the use of the pull-down menus, the evaluators focused the analysis on the change event in the timetable page and it was thus possible to detect that the use of these elements was not optimal. Some users did not use the filters to narrow the query results and so it took longer to find the requested piece of information. In particular, the usability problem detected was the lack of meaningful labels in the form elements for filtering according to time and flight type.

For the accomplishment of the last task (Find information on Boeing 737-300) the evaluators noticed that the optimal session took about 90 seconds going through six pages while the user sessions usually took about the double of the time. They compared the paths followed in the navigation by the users and found that they sometimes took the wrong direction and then they had to get back to find the right one. The analysis moved to the screendumps of the pages where such deviations occurred and found that users had to select the link "On Board" to access the relevant part of the Web site but that text was not particularly meaningful to understand this.

In general, the use of the environment was satisfying, and improved over time. The comparison of the issues indicated by the end users and those detected in the evaluation through the tool provided similar results.

Conclusions and Future Work

We have presented novel solutions for the interactive visualization and analysis of logs associated with users interactions with Web mobile applications in order to better support they remote usability evaluation. We also carried out a user test on an example application that showed that the tool can be used in real remote tests.

Future work will be dedicated to further applying the environment to the evaluation of mobile Web applications, and investigating the integration of the intelligent log analysis with an automatic analysis of the accessed Web pages to check whether they have been implemented according to usability and accessibility guidelines.

Fig. 1 .

 1 Fig. 1. An example of a set of timelines aligned according to one page access.

Fig. 3 .

 3 Fig. 3. An example of SAM analysis report on the pages accessed

http://wurfl.sourceforge.net/

http://mobile.lufthansa.com


Fatoumata Camara
email: fcamara@objetdirect.com

Gaëlle Calvary
email: gaelle.calvary@imag.fr

Rachel Demumieux
email: rachel.demumieux@orange.ch

The PEW Framework for Worth Mapping

Keywords: Interactive systems design, worth, Worth Maps (WMs)

In Human Computer Interaction, it is more and more clear that usability is not enough. In order to take into account the other criteria that may be relevant for design, G. Cockton introduced the notion of "worth" and the Worth Centered Design (WCD) framework for its operationalization. The WCD framework structures the development process and provides designers with a set of tools, including Worth Maps (WMs). Worth maps connect systems attributes to human ones, and as such represent a promising tool. However, they remain understudied and under-experimented. This paper presents the results of our experience with WMs. More precisely, it proposes the PEW (Perceived and Expected Worth) framework for worth mapping, reports findings from a study conducted with 5 experts regarding many aspects of WMs, and discusses future directions for research.

Introduction

The need to go beyond traditional criteria (e.g., usefulness, usability, learnability) in interactive systems design has been identified since years. For instance, the notion of emotional usability was formulated by Logan already in 1994 [START_REF] Logan | Behavioral and emotional usability: Thomson Consumer Electronics[END_REF].

With the advent of ambient computing, this concern is becoming more and more important. Indeed, nowadays, the user is provided with the opportunity to interact with a large number of systems serving different purposes, using different kinds of devices, in different settings. This diversity of types of systems and of contexts of use has then given good opportunities to point other criteria relevant to consider in interactive systems design. For instance, from interviews that followed the field trial of the "Whereabouts clock" (a physical device that displays family members current location) elements such as reassurance, connectedness, expression of identity, and social touch emerged [START_REF] Brown | Locating Family Values: A Field Trial of the Whereabouts Clock[END_REF].

More recently, many works have investigated additional criteria for interactive systems design through new notions such as the new usability [START_REF] Thomas | Introduction to the new usability[END_REF], the User eXperience (UX), or worth. The work presented here is related to the last aforementioned notion, worth, initially introduced as 'value' by G. Cockton in 2004 [6], as well as the WCD framework for worth operationalization. The WCD framework structures the development process around 4 phases [START_REF] Cockton | Designing worth is worth designing[END_REF]: (1) study of needs, wants, and unfelt needs (for worth elicitation), ( 2) design (for the system design and implementation), and (3) evaluation (for worth accomplishment) that my lead to iteration. G. Cockton also proposes a set of tools, including Worth Maps, for supporting the WCD.

From a theoretical point of view, the WCD appeared to be well suited for the design of next generations of interactive systems. For instance, in [START_REF] Vanden Abeele | User eXperience Laddering with preschoolers: unveiling attributes and benefits of cuddly toy interfaces[END_REF], the authors argue that "the framework is particularly relevant for designing pleasurable, enjoyable and entertaining interaction." However, despite having this potential, the WCD has not received much attention from community. Indeed, the relevant literature regarding worth and the WCD framework has been essentially produced by Cockton (and colleagues). This notice motivated our work.

Our final goal is to promote the WCD through lessons of experience from a complete operationalization of the framework and the development/improvement of tools for supporting the method. In an earlier work, we have investigated the worth of a system named Cocoon (study of needs, wants, and unfelt needs). This work allows us a better understanding of the notion of worth. In a further step, we have engaged in worth mapping sessions (prior to design and implementation) for the so-called system in collaboration with five experts involved in interactive systems design. This paper reports our experience with worth maps. Outcomes from this experience are twofold:

(1) we propose a framework for worth mapping, so called the PEW (Perceived and Expected Worth) framework; (2) we provide insights regarding WMs representation, construction, and interest.

2

Background literature

Worth

Worth is anything that motivates the user to buy, learn, use, or recommend an interactive product, and ideally most or all of these [START_REF] Cockton | Designing worth is worth designing[END_REF].

The WCD begins by the identification of worthies and supports several starting points (e.g. field study [START_REF] Cockton | Evolving and augmenting worth mapping for family archives[END_REF], sentence completion [START_REF] Cockton | Supporting Worth Mapping with Sentence Completion[END_REF]). In order to study the worth of Cocoon, a mobile and context-aware system that automatically pushes personal information (e.g. related to a maternity where a relative was born) and impersonal information (e.g. an historical building) to the user, we conducted 19 semi-directed individual interviews using storyboards. In order to surface elements beyond traditional criteria considered in Human-Computer Interaction (HCI) design, interviews focus not only on the "what" (features) and slightly the "how" (interface and interaction) but also on the "why" (motivations). Outcomes allowed a further understanding of worth.

 Worth is multidimensional

Outcomes from interviews revealed that worth is related to several aspects. Most of classes of elements identified from the analysis of existing WMs (see section 2.2) emerged from interviews: features (e.g. contextual information push), qualities (e.g. easy to use), consequences from usage (e.g. discovery of new places and new stories), and worthwhile outcomes (e.g. social impacts: maintain of ties). Interviews also revealed that associations of the aforementioned elements may activate the user' personal values such as family, friendship, freedom, and so on.

 Worth is twofold

During interviews, participants mentioned: ─ The positive side of Cocoon (i.e. what would motivate them to buy, learn, use, or recommend the system). We called this positive side: the "perceived worth". ─ The negative side of Cocoon (i.e. what would not make them buy, learn, use, or recommend the system): aversions, missing or poorly addressed features. We called elements that compensate this negative side: the "expected worth". For example, the two following verbatim are examples of aversions that the possibility of controlling the number of notifications from Cocoon compensates: "I don't want to receive information everywhere otherwise I would have too much information"; "Can you imagine? I would be notified every time I pass near a building in order to inform me that a relative worked here."

Intuitively, there is no expected worth in a perfect system and the goal of design should be to transform the expected worth to perceived worth.

 Worth is related to the system As we mentioned above, worth is also related to personal values. However, interestingly, interviews revealed that it is tied to the system from a user's point of view. Consequently, "worth" is "worth of the system."

Worth Maps

WMs are inspired from Hierarchical Value Maps (HVMs) [START_REF] Reynolds | Laddering Theory, Method, Analysis and Interpretation[END_REF] used in Marketing to study customer motivations for purchase. An HVM is a diagrammatic integration of separately elicited Means-End-Chains (MEC) [START_REF] Gutman | A Means-End Chain Model Based on Consumer Categorization Processes[END_REF]. A MEC links a product attributes (concrete/abstract) to its desirable and undesirable consumption consequences (functional/psychosocial) that are in turn linked to values (instrumental/terminal). WMs revisit HVMs in several points which are detailed in [START_REF] Cockton | Evolving and augmenting worth mapping for family archives[END_REF]. In HCI, WMs connect system-oriented attributes to user-oriented ones, thus shifting from "designing as crafting to designing as connecting" [START_REF] Cockton | Supporting Worth Mapping with Sentence Completion[END_REF]. From an analysis of existing WMs, we have identified the following classes of system-oriented attributes: materials, features, qualities (of features); and the following classes of user-oriented attributes: usage consequences (i.e. actions, feelings, UX), worthwhile outcomes, aversions, and adverse outcomes.

WMs follow a vertical representation. The system-oriented attributes connected to user-oriented ones are placed above aversions and adverse outcomes. However, it is important to note the negative side (aversions and adverse outcomes) are not generally shown on WMs because they are supposed to be overcome by the upper side elements: "the benefits are worth the costs". Thus, a WM models an ideal system.

WMs support design in different ways. First, they represent a means to ensure that the system satisfies users' expectations (credibility [START_REF] Cockton | Getting there: six meta-principles and interaction design[END_REF]). Second, WMs maintain the design team focused on the design goals (commitment [START_REF] Cockton | Getting there: six meta-principles and interaction design[END_REF]) relevant evaluation criteria can be instantiated according to associations highlighted in WM [START_REF] Cockton | Putting Value into E-valu-ation[END_REF]. As such, WMs represent a support for evaluation.

3

Worth Mapping for Cocoon

Individual interviews with experts

An initial version of the framework was produced on the basis of results from the study of worth of Cocoon and an analysis of existing literature regarding HVMs and WMs. This framework and an instantiated WM for Cocoon were then submitted to five people involved in interactive systems design as support for discussions during semi-structured individual interviews.

Interviews were conducted with: a project manager (7 years of experience), a User Interface (UI) and interaction designer (9 years of experience), a psychologist (12 years of experience), a graphic designer (15 years of experience), and a software engineer (11 years of experience). Participants worked for the research and development department of a telecommunication company and are used to work together within agile development teams.

Each interview lasted approximately 45 minutes. Interviews followed two goals: (1) assessing the understandability and the interest of WMs, (2) assessing the understandability and applicability of our framework. In order to reach these goals, interviews were structured around the following themes:  role(s) of the participant in the design process;  communication means and supports used in the participant's design team;  systems evaluations goals;  understandability and interests of WM (using Cocoon WM as example for illustration purpose);  understandability and applicability of the worth mapping framework (using the initial framework).

Results

Interviews were recorded using a Dictaphone and analyzed using a speech analysis. Results are summarized below.

 The framework for mapping Perceived and Expected Worth

The resulting framework, so called the PEW framework, (see Fig. 1) is only slightly different from the initial one. Indeed, regarding this aspect, participants' suggestions were mostly related to the form rather than to the content.

The major contribution of our framework is in reflecting the actual system (instead of an ideal one), at a given time (from a user's point of view) by making explicit both positive (perceived worth) and negative (expected worth) associations. This introduces implicitly another use of WMs as support to evaluation based on comparison of WMs representing the system at different design stages.

Our framework also suggests a vertical representation for WMs. Following existing representation patterns, the framework suggests representing positive associations (perceived worth) up and negative ones (expected worth) down. The Native Software and Hardware Components (NSHC) of the device hosting interaction may support features: they represent a key class of elements for WMs. As they are shared by both perceived and expected worth, they naturally come in the middle. It is important to note the linkage among the user-oriented attributes is simplified on the proposed framework: a hierarchy may exist (see Fig. 2).

Participants of interviews investigating WMs use and interest for interactive systems design suggest that boxes borders and links width corresponds to their importance. Thus, relevant elements can be visually identified at first glance.

 WMs construction

Regarding construction of WMs two points appeared to be critical: worth elicitation and the base support for worth mapping. For instance, the psychologist asked whether WMs should be constructed manually from scratch (on the basis of worth elements). According to her, the worth mapping process may require too much time to be applicable in realistic design processes. Indeed, the study of users' deep motivations requires a careful analysis. Moreover, our experience shows that the construction of WMs from scratch is a fastidious task.

Participants then proposed the ontology for worth associating already elicited worth elements to different types of system, device, user, or features as well as tools that support construction of WMs. They also suggested that WMs are interactive and the developer suggested involving users in the construction of WMs.

 WMs interest

Outcomes from discussions with interactive systems design experts highlighted additional interests of WMs for designing.

─ WMs as support to UI and interaction design According to the interaction designer, WMs may support UI and interaction design through qualities. For instance, an expected quality of modularization (see Fig. 2) suggests organizing the UI using different blocks.

─ WMs as support to graphic design

According to the graphic designer, WMs may support his design activity through user-oriented attributes and, especially, through UX elements. More precisely, a WM would inspire him in the choice of the design "ambiance": color, graphical elements, etc. For instance, according to him, he will not hesitate to use joyful colors for Cocoon as the study of worth revealed amusement as an UX element (see Fig. 2).

─ WMs as support to system implementation According to the software engineer, WMs may provide software developers with directions for coding through functional qualities (e.g. rapidity (response time)).

─ WMs as support to communication

Interviews were conducted with experts addressing different aspects of design. Yet, WMs appeared to be useful for each of them. All the five participants and, particularly the project manager, agreed that WMs may represent a common support for multidisciplinary teams, giving them an overview of the system regarding different aspects.

WMs as support to implementation was less stressed out by the software engineer than WMs as support to interaction and graphic design. However, the software engineer appreciates that WMs convey "what is important to the user". According to him, as he is not heavily involved in user studies, that "gives meaning to his work".

Conclusion and Future Work

This paper presents results of a preliminary work on worth maps in interactive systems design. To our best knowledge, this work represents the first attempt of the WCD framework operationalization by a research team not including the method author.

This paper provides a better understanding of the notion of worth, proposes the PEW framework, and highlights additional interests of WMs for HCI design.

More interestingly, this work highlights numerous directions for future research. In the short term, we will validate the applicability of our framework from its use by other design teams. At the same time, we will conduct further investigations regarding WMs different uses, elicited from this work, for supporting design activities through the development of Colibri, an Advanced Planning System (APS).

In the long term, we will explore the ontology for worth and focus on the development of tools, such as LadderUX i , for WMs construction.

Fig. 1 .

 1 Fig. 1. The PEW framework

Fig. 2 .

 2 Fig. 2. The WM of Cocoon (partial) -The chain highlighted in blue can be read as follows: the contextual information push feature supported by the GPS of the mobile device presents the quality of being diverse (because serves the user with different types of information, personal and impersonal); this diversity enhances discovery of new things which results in a gain of general knowledge for the user.

Acknowledgement

We warmly thank the national SYSEO project (ANR 2010-2014) for its support to this work.