Florian Frische
email: frische@offis.de

Andreas Lüdtke
email: luedtke@offis.de

The Difference Matters: Benchmarking Visual Performance of a Cognitive Pilot Model

Keywords: Human Performance Modelling, -Validation, -Analysis, Goodnessof-Fit Measures

In this paper we introduce an approach to objectively validate visual performance of a cognitive pilot model using benchmarks of human performance. A study with 16 human airline pilots and two competing models has been conducted in order to validate visual performance of the models applying these benchmarks. The study shows that human performance benchmarks can support analysts with a powerful and easy to use method for validation of human performance models. The benchmark is part of a largerscale method, which will be developed in order to evaluate human factors issues of future HCI-concepts in early stages of system design.

Introduction

The European project HUMAN 1 aims at developing virtual pilots, in order to improve the human error analysis of new cockpit systems. The virtual pilots should allow simulation-based testing of new cockpit system designs in early design phases. This enables simulating a huge number of scenarios in accelerated time in order to identify potential problems in the operation of new systems (e.g. human errors due to clumsy automation [START_REF] Wiener | Human factors of advanced technology (glass cockpit) transport aircraft[END_REF]) and to derive necessary improvements. The virtual pilots in HUMAN are based on a cognitive architecture named CASCaS (Cognitive Architecture for Safety Critical Task Simulation) [START_REF] Lüdtke | Cognitive modelling of pilot errors and error recovery in ight management tasks[END_REF] which is an implementation of the information processing paradigm of human cognition (similar to ACT-R [START_REF] Anderson | An integrated theory of the mind[END_REF] and MIDAS [START_REF] Gore | Increasing aviation safety using human performance modeling tools: An air man-machine design and analysis system application[END_REF]).

Pilots flying modern aircrafts are confronted with many information (e.g. weather conditions, flight plans, air traffic and automation modes) that are mainly presented on visual displays. Consequently, pilots' vision is the main cognitive resource (apart from auditive and haptic resources) for gathering information about the aircraft and the outside world. Thus, a sophisticated and thoroughly validated visual perception model is a pre-condition for simulating pilot-like interaction with visual interfaces.

Evaluating the predictive power of visual performance models is very complex and time consuming because human visual performance [START_REF] Anderson | An integrated theory of the mind[END_REF] is very variable between different pilots as well as within a single pilot and ( 2) is a combination of different aspects, such as glance duration, glance frequency and scanpaths. Methods, techniques and tools are needed that can easily be applied by analysts to evaluate model performance.

In HUMAN we validated the performance of CASCaS by comparing data produced by the model with data produced by human pilots in experimental simulator studies, both flying the same scenarios. We developed a benchmark approach that is used in combination with traditional validation techniques. Benchmarks are commonly understood as an analysis method to objectively compare characteristics of subjects with characteristics of a reference subject. The measures considered for the analysis usually characterize the overall power of the system with regard to a target question [START_REF] Zhang | Application-specific benchmarking[END_REF]. Our benchmark approach provides a catalogue of objective measurement criteria allowing (1) to compare the fitness of competing models, (2) to find the best fitting model and (3) to decide objectively if the predictive power of a model is sufficient for the desired application.

In this paper we will briefly introduce our benchmark approach, which we call Human Performance Benchmarking and present results of two CASCaS versions that have been compared in order to find the best fitting model. The paper is organized as follows: In Section 2 we present related work in the area of human model validation. Next, in Section 3 our approach will be introduced. In Section 4 we present exemplary results of a first application of the Human Performance Benchmarking. Finally, in Section 5, we will summarize the paper and point out potential improvements of our approach, identified based on the study results. The Human Performance Benchmarks are part of a larger-scale method, on which we are currently working in order to evaluate human factors issues of future HCI-concepts in early stages of system design.

Related Work

Different measures, mainly of descriptive statistics, have been used in order to demonstrate the fit of model performance to human performance based on quantitative data (see e.g. [START_REF] Frische | Modelling and validating pilot visual attention allocation during the interaction with an advanced ight management system[END_REF], [START_REF] Salvucci | Modeling driver behavior in a cognitive architecture[END_REF] and [START_REF] Ball | Comparing three variants of a computational process model of basic aircraft maneuvering[END_REF]). These measures can be categorized in three types:

Measures of central tendency 2. Measures of dispersion 3. Measures of association

The most common type of measure used in the area of model validation are measures of central tendency, e.g. mean, median and mode. Measures of central tendency describe the center or middle of a given data distribution by mapping multiple performance values on a single value. Thus, measures of central tendency are not sufficient to describe the variability in human performance. Measures of central tendency in combination with measures of dispersion are used to describe the local fit between human and model performance data, see e.g. [START_REF] Salvucci | Modeling driver behavior in a cognitive architecture[END_REF] and [START_REF] Frische | Modelling and validating pilot visual attention allocation during the interaction with an advanced ight management system[END_REF]. Combining mean (as measure of central tendency) and standard deviation (as measure of dispersion) allows to quantify the average case and variability of human and model behavior based on given data samples. Fig. 1A shows an example for measuring distribution of gaze on areas of interest. The combination of mean and standard deviation provides a qualification of local fitness between datasets. Nevertheless, they do not quantifiy fitness. Quantification is especially needed if analysts have to validate different versions of a model in order to find the best fitting one. Measures of association are used to quantify the relation between model data and human data by calculating the trend fitness between the two datasets. Fig. 1B shows an example for comparing the rank order of the pilots' gaze distribution. Here, Pearson is used to quantify the consistency of the rank order for the two data sets. Nevertheless, measures of association do not take into account the variability within human performance. Quantifications calculated based on measures of association provide only poor evaluation of the fitness between model and human data because they do not consider behavioural variability. It is not possible to draw any conclusion about the final predictive power of the model. Thus, a measure is needed which on the one hand considers variability in human performance and on the other hand quantifies model performance in comparison to human performance. First approaches to provide such a measure have been researched by Schunn and Wallach, and by Gluck. Schunn and Wallach provided a measure for quantification of local fitness in [START_REF] Schunn | Evaluating goodness-of-fit in comparison of models to data[END_REF]. They recommend using the root mean square deviation (RMSD) as a measure of local fitness. RMSD calculates the difference between a set of related performance values and merges them on a single value of predictive power. Thus, RMSD allows comparing performance of different variants of a model on a quantitative basis. However, the problem analysts are faced with when using this approach for validation of local fitness is analog to the problem when using Pearson, that is the absence of taking into account human performance variability. This problem has been tackled by Gluck et al. in [START_REF] Gluck | A computational process model of basic aircraft maneuvering[END_REF]. They proposed an approach to validate a pilot model, taking into account the between-subject differences of a set of human performance datasets instead of absolute performance values. The betweensubject differences served as a reference in order to actually evaluate the goodness-offit of a pilot model m. For a group of human subjects S, they calculated the difference in performance of each individual subject s k to the average performance of S\s k using RMSD. The result was a set of difference values describing the natural variability of human performance which has been used to evaluate the difference between m and S. When analysing visual data, one of the characteristics most frequently described is the glance distribution on a set of pre-defined areas of interest. Here, RMSD for local fitness and Pearson for trend fitness can be used to calculate the difference between two subjects. Consequently, for a group of n human subjects, the result can be described as a bi-directional complete graph K n (see Fig. 2) where K denotes the graph and n depicts the number of nodes. Edges i↔j are labeled with a value v ij representing the difference (RMSD or Pearson) between s i and s j . Thus, the graph completely describes the differences between human subjects (difference graph). The same approach can be used for measuring differences between human subjects and human performance models. Human Performance Benchmarks use difference graphs as the basis in order to validate visual performance of human models tackling quantification of visual performance and taking behavioural variability into account.

Human Performance Benchmarking

Benchmarks are commonly understood as an analysis method objectively comparing characteristics of subjects with characteristics of a reference subject. The measures considered for the analysis usually characterize the overall power of the system with regard to a target question [START_REF] Zhang | Application-specific benchmarking[END_REF]. A benchmark is a quantitative test evaluating the characteristics observed and matching results on a scale which is independent from the characteristics. Thus, results of different characteristics can be aggregated and evaluated on different levels of abstraction. This allows analysts to identify strengths and weaknesses of systems objectively based on data. The similarity evaluation in step 4 can be defined as a function sim c (m,S) evaluating for each c, if the performance of a given m is human-like, where human-like performance is determined by S. Our first version of this function is a naive boolean function returning true if mean m is covered by CI S and false if mean m is not covered by CI S :

     else false CI mean true s m sim S m c | | ) , ( (1)
In step 5, fit m is calculated. We define fit m as the sum of true similarity evaluations divided by the sum of all (true or false) similarity evaluations. Thus, the range of fit m is [0;1], where 0 means no fitness and 1 means total fitness. Based on fit m , analysts can decide if a model's performance is sufficient for the desired application or not. A model is sufficient, if fit m ≥ thres, where thres is a pre-defined threshold parameter. The application of this algorithm allows considering performance variability in terms of between-subject differences provided by difference graphs (step 1) which are used to calculate an interval CI S which represents the variability (step 2). In addition, the algorithm allows quantification of fitness by applying sim c (m,S) (step 4) and calculating fit m (step 5) as a measure of model fitness. In the following Section, we will present exemplary validation results of an application of Human Performance Benchmarks in order to preliminary assess the approach.

Results

Experiments with 16 human airline pilots have been conducted in order to collect reference data for the validation of the visual performance data of our pilot model.

Performance data of human pilots and two competing model versions (m 1 and m 2 ) have been validated based on data of glance distributions during three flight phases (cruise (1), approach (2) and final approach (3)), see Fig. 3A. Accordingly, the benchmark has been used to quantify performance and to objectively evaluate fitness of m 1 and m 2 for three performance characteristics c 1 (glance distribution during cruise phase), c 2 (glance distribution during approach phase) and c 3 (glance distribution during final approach phase):

Step 1: We computed the corresponding difference graph for c 1 , c 2 and c 3 taking into account the 16 subject pilots S and m 1 and m 2 . Due to size limitations the graphs are not shown here.

Step 2: We computed CI S for c 1 , c 2 and c 3 . The results are shown in Fig. 3B.

Step 3: We calculated mean m1 and mean m2 . The results are shown in Fig. 3B.

Step 4: We evaluated the similarity between m 1 and S, and between m 2 and S. The results are shown in Table 1. According to the similarity function defined in Section 3, Fig. 3B shows that only m 1 receives a true evaluation (sim c2 (m 1 ,S) = true).

Step 5: Results of step 4 have been used to calculate the overall fitness value of m 1 and m 2 . The results are shown in Table 1. For the datasets analysed in this study, the overall fitness value of model 1 is .33 and the evaluation of model 2 is 0. The fitness values can be used to evaluate if these models are sufficient for the desired application based on a comparison of each fitness value to thres. (e.g., if analysts define thres = .3, then m 1 would be sufficient).

Summary and Future Work

In this paper, we presented an approach (called Human Performance Benchmarking) for quantitative evaluation of goodness-of-fit for human performance models based on quantitative performance data. The approach considers variability in human performance and uses these performance differences as a model evaluation reference. A first naive evaluation function has been presented, which evaluates the model fitness in context of these reference data. The benchmarking approach has been applied within a study with aircraft pilots focusing on gaze data. The results have been presented and issues requiring improvements have been identified. The first issue is that the evaluation function is very simple and results may be misleading for models that perform just within the human performance intervals. Evaluation of these models would be similar to those that perform much better and would considerably differ from models that perform slightly worse. We plan to improve the evaluation function by weighting the distance to the center of the distribution. The second issue is that the function works fine for deterministic models (same input -same output) but models like CASCaS produce performance variance as well. We have not yet taken variability in model performance into account. We plan solving this issue by considering CI m instead of mean m for a set of model runs and to compare CI m to CI S .

Fig. 1 .

 1 Fig. 1. Comparison of glance distribution of pilots in a flight simulator study conducted at German Aerospace Center (DLR). Chart A depitcts a common bar chart used to visualize local fitness including the mean and standard deviation for each area of interest. Chart B depicts the mean glance distribution as line chart (which is more intuitive for analysing trend consistency) including Pearson (r) as a quantification of trend fitness. However, variability of pilot behavior has to be considered during cockpit design, because the design has to be safe and usable for different types of pilots. Measures of dispersion are used to describe the between-subjects variability and the within-subject variability. Typical measures of dispersion are range, standard deviation and confidence intervals. Finally, measures of association are used (1) to describe the relation of data points of a sample to data points of another sample, or (2) to describe the relation between parameters within a sample. Typical measures of association are Pearson's correlation coefficient (in the following referred to as Pearson) and Spearman's or Kendall's rank order correlation. All three types of measures are frequently used to validate models of human performance with different strength and weaknesses.Measures of central tendency in combination with measures of dispersion are used to describe the local fit between human and model performance data, see e.g.[START_REF] Salvucci | Modeling driver behavior in a cognitive architecture[END_REF] and[START_REF] Frische | Modelling and validating pilot visual attention allocation during the interaction with an advanced ight management system[END_REF]. Combining mean (as measure of central tendency) and standard deviation (as measure of dispersion) allows to quantify the average case and variability of human and model behavior based on given data samples. Fig.1Ashows an example for measuring distribution of gaze on areas of interest. The combination of mean and standard deviation provides a qualification of local fitness between datasets. Nevertheless, they do not quantifiy fitness. Quantification is especially needed if analysts have to validate different versions of a model in order to find the best fitting one. Measures of association are used to quantify the relation between model data and human data by calculating the trend fitness between the two datasets. Fig.1Bshows an example for comparing the rank order of the pilots' gaze distribution. Here, Pearson is used to quantify the consistency of the rank order for the two data sets. Nevertheless, measures of association do not take into account the variability within human performance. Quantifications calculated based on measures of association provide only poor evaluation of the fitness between model and human data because

Fig. 2 .

 2 Fig. 2. Difference graph describing the individual performance differences of human subjects (square) to each other as well as the differences between human subjects and a model (circle), or between competing model versions. The intention of our benchmark for visual performance is providing a goodness-of-fit evaluation for different characteristics C (such as glance distribution, glance frequency or scanpaths) for a set of competing models M with regard to a set of human subjects S. Our benchmark algorithm calculates an individual fitness value for each model m  M. Fitness values can be used (1) to compare the fitness of competing models, (2) to find the best fitting model and (3) to decide objectively if the predictive power of a certain model is sufficient for the desired application. In the following, the algorithm used to calculate a model's fitness value is presented: 1. For all c  C, calculate difference graph for m and S 2. For all c  C, calculate confidence interval CI S of individual difference values in S 3. For all c  C, calculate the mean mean m of differences between m and S 4. For all c  C, evaluate similarity between m and S 5. Calculate overall fitness value fit m of m based on similarity evaluations of each c

Fig. 3 .

 3 Fig. 3. Chart A depicts the glance distributions (AOIs: Advanced Human Machine Interface (AHMI), Primary Flight Display (PFD), Navigation Display (ND), Engine Display (ED), Electronic Flight Control Unit (EFCU) and Window (WND)) of a human population (mean and standard deviation) and two concurring models for three flight phases (cruise (C), approach (A) and final approach (F). Chart B depicts the mean values and confidence intervals (95\%) of human pilots and the mean values of model 1 and model 2, which have been calculated based on the difference graphs for the flight phases.

Table 1 .

 1 Results of benchmarking reveal that m 1 receives a higher overall fitness value than m 2

	Model	Cruise	Approach	Final Approach	Overall Fitness Value
	m 1	false	true	false	.33
	m 2	false	false	false	.0

7th Framework Programme, see http://www.human.aero for further information about the project

Acknowledgments

The work described in this paper is funded by the European Commission in the 7th Framework Programme, Transportation under the number FP7 -211988.


Larissa Pschetz
email: l.pschetz@dundee.ac.uk

Time affordances and physical mobility in the context of ubiquitous technologies

Keywords:

This research aims to use design demonstrators to speculatively explore the relation between perceived time affordances and physical mobility in the context of ubiquitous technologies.

Introduction

Recent interconnections of physical movement and communication systems are increasingly detaching geographic locations from underlying concepts of distance and co-presence [START_REF] Cresswell | On the Move[END_REF]. As handheld devices allow a large number of activities to be performed on the go, individuals are encouraged to undertake longer hours of travel, and distance becomes ever more irrelevant. As a result, networks start to be structured more around individuals than around places, homes and contexts [START_REF] Elliott | Mobile Lives[END_REF]. Daily schedules can be negotiated dynamically and become increasingly desynchronised from work, community and place, and hence from each other [START_REF] Southerton | Harried and hurried: time shortage and the coordination of everyday life[END_REF]. Technological developments not only contribute to free networks from geographical boundaries, but also set less utilitarian roles for spatial cognition [START_REF] Burnettand | The effect of vehicle navigation systems on the formation of cognitive maps[END_REF] -as GPS-devices specifically and general automated travel technology enable people to navigate in completely unfamiliar settings with no prior planning [START_REF] Rajamani | Vehicle Dynamics and Control[END_REF].

Mobility thus is less constrained by geographic distances and is increasingly detached from spatial cues. It is however still and increasingly bound to individuals' schedules and personal relation to time [START_REF] Elliott | Mobile Lives[END_REF]. Though there has been a lively debate among social scientists [START_REF] Wajcman | Life in the fast lane? towards a sociology of technology and time[END_REF] on possible new notions of time provided by new technologies, there has been little research on relations between time perception and human mobility, and even less on the practical consequences of such notions for the design of new technologies. In HCI, supporting physical mobility is mostly associated to improving mobile infrastructure (e.g. accessibility [START_REF] Nilsson | Ability by mobility[END_REF], privacy [START_REF] Tarasewich | Protecting private data in public[END_REF] and services [START_REF] O'hara | Everyday practices with mobile video telephony[END_REF]), or to facilitating wayfinding e.g. [START_REF] Leshed | In-car gps navigation: engagement with and disengagement from the environment[END_REF]. While the first focuses on setting up the context of ubiquitous computing, the second approaches only one immediate aspect of physical mobility. As asserted by sociologist John Urry [START_REF] Adey | Mobilities, meetings, and futures: an interview with John Urry[END_REF], demand for travel and movement tend to be treated as "either self-explanatory or exogenous to the system". Therefore, the present research intends to extend the current HCI discussion by considering physical mobility within a broader context. In particular, it will investigate the social ecologies around time perception and how it influences individual movements.

Research hypothesis

The main hypothesis of this research is that physical mobility patterns in ubiquitous technological contexts are more strongly influenced by perceived time affordances than by geographic constraints. The idea is that, in highly technological contexts, individuals' movements are triggered, delayed and paced, not by notions of geographic distances nor by difficulties in localising routes, but by the perception that a schedule can be negotiated, meeting times can be squeezed, or that a place can be reached within a certain period of time. Technologies provoke multidimensional practices of time and new meanings of temporality [START_REF] Hörning | Do technologies have time?[END_REF], which consequently influence movement.

The challenge of this research is to harness technology that not only recognises, but celebrates the fact that perceived time affordances can vary greatly according to different social backgrounds and access to different technologies.

Methodology

The chosen methodology can be divided in four different phases as follows:

1) Development of demonstrators. Based on literature review and ethnographybased methods [START_REF] Macaulay | Ethnography, theory and systems design: from intuition to insight[END_REF], major influences of current technological devices on physical mobility have been initially identified. By emphasizing time as the main driver for physical movement, mobility was then speculatively projected [START_REF] Kerridge | Does speculative design contribute to public engagement of science and technology?[END_REF] into different scenarios, which did not intend to fit or present an accurate account of reality. Instead, it attempted to exaggerate critical aspects of pre-defined subjects in order to stimulate discussion. Such speculations were then translated into concrete products [START_REF] Zimmerman | An analysis and critique of research through design: towards a formalization of a research approach[END_REF] that embodied these critical aspects in order to let participants experience alternative situations and later discuss their experiences. The design process consisted in exploratory and playful experimentations [START_REF] Gaver | Alternatives: exploring information appliances through conceptual design proposals[END_REF] with different kinds of hardware and information technology services, in which methods such as experience prototyping [START_REF] Buchenau | Experience prototyping[END_REF] and the already cited scenarios [START_REF] Bødker | Scenarios in user-centred design: setting the stage for reflection and action[END_REF] were included. I will now present two examples of demonstrators developed in the context of this research.

a) The Family Clock speculates on the increasingly temporal flexibility provided by handheld devices. A family shares a clock whose rhythm is set collectively by its members according to their individual pace of life. The physical clock is placed in a common room, while its time is sped up or delayed throughout the day via family members' mobile phones until it reaches equilibrium. The clock allows families to choose their own temporal state, which can be slightly slower or faster than universal time.

b) The Transportation Clocks address issues of distance and social attachment. A pair of clocks constantly displays the time necessary to reach each other based on pubic transportation schedules. Serving as a dynamic souvenir of the person, its aim is not to fulfil utilitarian purposes, but to present a more personal way of perceiving time and distance, which in turn is expected to prompt discussion on the way these dimensions are generally perceived.

2) Experience evaluation. The developed design demonstrators will be presented to groups of users in order to discuss the relevance of each embodied subject. Though the circumstances of such assessment vary according to each demonstrator, participants will be asked to carry the artefacts or keep them at their homes for extended periods of time. During this period they will be asked to keep a written, visual or spoken diary of their impressions. Prompts developed based on ethnographic practices [START_REF] Macaulay | Ethnography, theory and systems design: from intuition to insight[END_REF] will be provided to support the records. These practical experiments will be followed by focus groups or semi-structured interviews, which will allow us to understand the rationale behind methods adopted to record impressions, as well as formal features, potential for raising discussion, and the relevance of issues embodied by each designed artefact.

3) Refinements. It is expected that the evaluation phase will provide insights for refinements or for the development of new demonstrators, in an attempt to increase the complexity of proposed subjects. These refinements, in turn, will lead to new evaluations, in an iterative process.

4) Guidelines definition.

Based on the insights gained at the evaluation phase, a set of guidelines will be defined to allow future researchers to either reproduce or apply the knowledge generated in the process.

Expected contributions

This research will provide design-led evidence to support speculations on the future of physical mobility. By looking beyond the solving of problems related to mobility, towards an approach that explores the opportunities presented by existing and emerging technologies, the research expects to expand the scope of current HCI analysis on spatial mobility, generating new knowledge for mobility technology through: a) discursive accounts of user experiences of artefacts that play with perceptions of time and movement, b) a design based lens for looking deeply at mobility opportunities, c) a series of prototypes and artefacts that demonstrate and enable discussion on these opportunities, d) a set of design guidelines for implementing a future that has a rich and ubiquitous use of mobility technology.

Supervisors: Jon Rogers (j.rogers@dundee.ac.uk), Chris Speed (c.speed@eca.ac.uk), and Richard Banks (rbanks@microsoft.com)

Acknowledgement. This work was supported by Microsoft Research through its PhD Scholarship Programme.


Juan Miguel López

Afra Pascual

Llucia Masip

Toni Granollers
email: tonig@diei.udl.cat

Xavier Cardet
email: xcardet@alumnes.udl.cat

Influence of Web Content Management Systems in Web Content Accessibility

Keywords: Web Content Management Systems, Authoring Tool Accessibility Guidelines, Web Content Accessibility Guidelines

Web Content Management Systems (CMS) are traditionally used in institutions to allow web content management by people without technical skills. This study intends to check the influence of the CMS in the accessibility of the contents they handle. First, an accessibility analysis of six widely used CMS is performed base don the Authoring Tool Accessibility Guidelines (ATAG). Second, an accessibility analysis of a series of city council web pages managed by abovementioned CMS by using Web Content Accessibility Guidelines (WCAG). Results of the study show that although web pages managed by the CMS with a better degree of ATAG fulfilment provide better accessibility, there is no direct correlation between results obtained in both evaluations. Information about what aspects cause accessibility errors in the CMS and the impact of such aspects in accessible web content management is also provided.

Introduction

Currently, there are powerful legal requirements to take accessibility into account as a requirement for developing web sites. For instance, these kinds of regulations have been performed on European Union countries [1]. It is important to note that these legal frameworks do not only affect public administration, but also corporations that develop software or provide services for their use in civil service.

Nowadays there is a wide range of institutions that use CMS to manage their web content. They are especially useful as they allow users without technical skills to introduce eliminate or modify web content, but it does have some risks regarding accessibility [2] [3]. Furthermore, CMS generally do not generate accessible web content by default and allow users to perform few modifications to improve the accessibility of the web content they manage. These kinds of modifications are frequently insufficient to allow websites to be accessible for people with disabilities [START_REF] Schulz | Web Compliance Management: Barrier-Free Websites Just by Simply Pressing the Button? Accessibility and the Use of Content-Management-Systems[END_REF].

Study

Six CMS were selected for the study. The selection was based on the CMS to be open source, commonly used in civil service and general purpose systems. Selected CMS were: Plone, Joomla!, Typo3, EzPublish, OpenCMS and Drupal. First, an accessibility analysis of the CMS on their default installations was performed based on the Authoring Tool Accessibility Guidelines (ATAG) [START_REF] Treviranus | Authoring Tool Accessibility Guidelines 1.0[END_REF]. In order to complete the study, a web content accessibility analysis was performed on a sample of 90 worldwide town council web pages, 15 of them managed by each CMS. Web Content Accessibility Guidelines (WCAG) [START_REF] Chisolm | Web Content Accessibility Guidelines 1.0[END_REF] were used for analysing the accessibility of each web page using the evaluation methodology established by the World Wide Web Consortium [7]. A total of three evaluators performed the study, each of them evaluating two CMS. Although it would have been desirable that every CMS would have been evaluated by more that one evaluator, the complexity of CMS led to estimate positively the fact that evaluators had a high level of knowledge regarding CMS to be evaluated. The results obtained by these evaluators were estimated to be more useful compared to the ones that people without such knowledge should provide. Evaluators also had deep knowledge on both accessibility guidelines used in this study.

Table 1. Quantitative results of the ATAG evaluation for every selected CMS Table 1 summarizes the results obtained in the ATAG evaluation, grouped by CMS. Rows are organized by the type of ATAG priority. Columns are labelled as: "C" (indicates the number of guidelines that were correctly fulfilled), "Ac" (indicates the number of guidelines with almost all requirements satisfied or bugs need to be fixed) or I (indicates the number of guidelines that were not correctly fulfilled). Guidelines with relative priority were evaluates separately, although it must be taken into account that they can be interpreted as different priority depending on the case. Table 2 resumes the results obtained in performed web accessibility evaluations. Due to space constraints, results are expressed by means of the number of accessibility errors for the different analysed guidelines, grouped by priorities. It must be taken into account that the table sums up all errors located for the 15 web pages analysed per CMS. On the other hand, Table 3 shows the mean ("M") and the standard deviation ("St") of the accessibility errors detected for the 15 web pages analysed per CMS, ordered by priority.

Priority Drupal EzPublish Joomla! OpenCMS Plone Typo3 C A c I C A c I C A c I C A c I C A c I C A c I 1 3 2

Discussion and Conclusions

Regarding quantitative results corresponding to the six analysed CMS, Drupal and Plone show more complete features regarding accessibility in their default installation. Anyhow, none of them achieved an "A" level of compliance regarding ATAG fulfilment. One of the main issues arising from the study is that the web editors used by default in analysed CMS do not allow generating accessible content. In this sense, they must be reconfigured, be discarded or allow installing web content editors external to the CMS so users can generate accessible web content. Another relevant aspect is the need to change default CMS templates, as they cause web elements' layout not to be accessible. The need to improve documentation regarding the accessibility that CMS provide is another aspect to assess.

Regarding the quantitative analysis of the web content accessibility of the sample of analysed web pages, it is remarkable the fact that a minimum number of web pages reaches even the "A" compliance level established by WCAG 1.0 [START_REF] Chisolm | Web Content Accessibility Guidelines 1.0[END_REF], despite the legality regarding accessibility that analysed web pages should fulfil. Interestingly, it is worth noting that only 1 web page managed by Plone and 9 managed by Drupal achieve such compliance level. Accessibility errors found in these web pages are due to a series of reasons:

1. Most priority 1 errors were due to the lack of a proper alternative text in images (WCAG 1.1 checkpoint) 2. A large number of web pages used absolute measures instead of relative ones to position elements in web pages (WCAG 3.4 checkpoint). 3. Use of device-dependent events (associated only to mouse events by) and lack of redundancy for these cases. 4. The fact that default installation of most CMS (except for Plone and Drupal) did not provide by default a clear content and layout separation has led to accessibility errors in almost all the web paged managed by them (WCAG 3.3 and 11.2 checkpoints).

The results of CMS accessibility evaluation show no direct correlation with the results of web accessibility evaluation. For instance, Plone shows relatively good results regarding ATAG fulfilment, but poor results regarding the accessibility of web pages managed using this CMS compared to other CMS. However, web pages managed using Drupal and EzPublish show less accessibility errors compared to the rest.

This work intends to highlight the necessity of the CMS to manage adequately the accessibility of the contents they manage. One interesting conclusion derived from this work is that all analysed CMS can be configured so they can be accessible. In order to do so, it is necessary to modify internal CMS classes and templates that adjust web content in an accessible way. Besides, the use of web content editors external to the CMS can allow managing accessible web code. There is also the option of including plugins in all the CMS that can be used to manage concrete aspects and can be used as tools to improve accessibility. Anyhow, all these solutions require deep and exhaustive knowledge regarding each CMS. There are some resources that allow improving CMS accessibility [START_REF] Connor | Choosing an Accessible CMS[END_REF] [9], but they do not provide a clear methodological approach in providing different concrete solutions. Furthermore, it is important to provide accessibility monitoring systems to check the accessibility of managed web content [START_REF] López | Engineering Accessibility in Web Content Management System Environments[END_REF].

Table 2 .

 2 Sum of detected accessibility errors for all web pages of each analysed CMS

	Priority Drupal EzPublish Joomla! OpenCMS Plone Typo3
	1	20	26	32	83	248	39
	2	341	167	566	1265	422	571
	3	83	98	219	168	169	105

Table 3 .

 3 Mean and standard deviation of detected accessibility errors for all web pages of each analysed CMS

	Priority	Drupal	EzPublish	Joomla!	OpenCMS	Plone	Typo3
		M	S t	M	S t	M	S t	M	St	M	St	M	St
	1	1,3 2,4 1,7 2,7 2,1 2,6 5,5 14,5 16,5 15,5 2,6 4,5
	2	22,7 32,3 11,1 14,1 37,7 44,1 84,3 98,2 27,8 30,5 38,1 70,7
	3	5,5 4,1 6,5 6,9 14,6 16,8 11,2 13,4 12	12	7,0 9,4

Acknowledgements. This work has been partially funded by Spanish Ministry of Science and Innovation through TIN2008-06228 and TIN2008-06596-C02-01 research projects. Llucia Masip is the recipient of a pre-doctoral fellowship from the University of Lleida.


Juan Pablo Hourcade
email: juanpablo-hourcade@uiowa.edu

Natasha E Bullock-Rest
email: natasha.bullock.rest@gmail.com

Janet C Read
email: jcread@uclan.ac.uk

Yoram Chisik
email: ychisik@gmail.com

HCI for Peace: Promoting Peace and Preventing War Through Computing Technology

Keywords: Peace, war, pervasive computing, conflict

Our aim in this SIG is to discuss the role human-computer interaction can play in bringing about peace by influencing socio-economic factors that affect the likelihood of conflict as well personal values involved in making decisions to support conflict.

Introduction

The increasing pervasiveness of computing devices provides human-computer interaction researchers with new opportunities to influence socio-economic and personal factors that affect the likelihood of war and peace. With this in mind, we have started an initiative called HCI for Peace to highlight and celebrate research with peace as its explicit goal. We also hope to form a community of researchers with an interest in using computing technologies to promote peace and prevent war in order to coordinate efforts, share ideas and have a greater impact. Our world can be no brighter than the worlds we dream of.

We have already begun building a community through activities at the CHI conference. During CHI 2010, 500 attendees wore peace ribbons on their name badges and engaged in discussions with others on the role human-computer interaction can play in promoting peace and preventing conflict. During CHI 2011, we are scheduled to present a full paper with a call for constructive action on peace [START_REF] Hourcade | HCI for Peace: A Call for Constructive Action[END_REF], and we will also have a panel discussion. In addition, we have setup a website at hciforpeace.org where we feature interviews and stories on human-computer interaction research for peace.

The INTERACT conference provides us with a unique opportunity to extend our discussions and our community internationally. Through a SIG, we expect to be able to gain new perspectives and bring more voices into the community.

Why Peace?

Peace is a very practical goal to pursue. One reason for this is that war is very expensive. For example, the United States spends roughly 2 billion USD every week on the conflicts in Iraq and Afghanistan [START_REF] Stiglitz | The Three Trillion Dollar War: The True Cost of the Iraq Conflict[END_REF]. War can also have a devastating economic impact on poorer countries, with most of the poorest countries in the world currently or recently involved in armed conflicts [START_REF] Stewart | Root causes of violent conflict in developing countries[END_REF]. The most horrible costs though are in terms of human lives, and in the trauma inflicted on those who survive.

Discussion

In our previous work [START_REF] Hourcade | HCI for Peace: A Call for Constructive Action[END_REF], we have approached the topic of peace and conflict by reviewing empirical studies on the causes of armed conflict at a socio-economical level. We have also looked into research on moral decisions at a personal level and how these can affect decisions to support war or to kill in the battlefield. Based on this review we have identified human-computer interaction research that is already being conducted and that could be conducted to positively affect both socio-economic factors and personal decisions. Recent events have made these discussions more concrete, with computer technologies, for example, playing a crucial role in (mostly peacefully) toppling dictatorships in Egypt and Tunisia earlier this year [START_REF] Khan | Lessons Learned from the Arab Spring Revolutions[END_REF]. Hosting a SIG will enable us to get new perspectives and discuss alternative ways of approaching research on peace.

A SIG will also be an opportunity to discuss some difficult questions. For example, what role can human-computer interaction realistically play in conflict prevention and resolution? How can we measure the effect of projects on peace and conflict? How can we identify the best situations in which computing technologies can play a positive role? How do we address multiple perspectives during a conflict? We hope these questions will generate fruitful discussions and produce useful ideas.


Tihomir Orehovački
email: tihomir.orehovacki@foi.hr

Prof. Dragutin Kermek

Development of a Methodology for Evaluating the Quality in Use of Web 2.0 Applications *

Keywords: Web 2.0, Quality in Use, Usability, User Experience, Subjective and Objective Measures, Evaluation Methodology

Quality in use is comprised of two seemingly different though interlocking concepts: usability and user experience. Consequently, complementary evaluation of pragmatic and hedonic attributes could significantly affect the acceptance of software applications. However, in the context of Web 2.0 applications this topic has still not attracted enough attention from the HCI community. Therefore we present a research aimed at developing a methodology that would facilitate the analysis and comparison of evaluated Web 2.0 applications.

Introduction

Quality in use is considered to be one of the most important factors that affect a wide acceptance of software applications. It is comprised of two seemingly different but rather complementary concepts [START_REF]Systems and software engineering -Systems and software Quality Requirements and Evaluation (SQuaRE) -System and software quality models[END_REF]. Usability refers to the product-centred evaluation of pragmatic attributes through the use of both subjective and objective measuring instruments. On the other hand, user experience (UX) consists of applying subjective measuring instruments on the assessment of hedonic attributes [START_REF] Hassenzahl | User experience -a research agenda[END_REF]. HCI literature contains a number of different models, methods, and standards aimed at evaluating the quality and usability of software applications like information systems, web sites, web portals and alike. However, the existing research related to the evaluation of Web 2.0 applications in general is fairly scarce. We strongly believe that this is accounted for by the inadequacy of current approaches for their evaluation, as confirmed by several recent studies. According to the research in Hart et al. [START_REF] Hart | Exploring the Facebook Experience: A New Approach to Usability[END_REF], the popular social networking site Facebook should not be an example of a success story because it complies with only two of ten heuristics originally proposed by Nielsen [START_REF] Nielsen | Heuristic evaluation[END_REF]. Hart et al. also reported that attributes such as ease of use, usefulness and playfulness have a major impact on user behavioural intentions. A study into usability evaluation [START_REF] Silva | Usability -Not as we know it![END_REF] revealed that YouTube had also met only two heuristics. Thompson and Kemp [START_REF] Thompson | Web 2.0: extending the framework for heuristic evaluation[END_REF] argued that the emphasis on user experience is one of the main reasons why Web 2.0 applications such as Flickr, Wikipedia and YouTube have a large number of active users. Moreover, they extended the Nielsen's set of traditional heuristics with two additional heuristics although the validity of that modified set has not been empirically confirmed. The findings stated above motivated us to initiate a research on the development of an evaluation methodology that would extend the concept of quality in use in the context of Web 2.0 applications.

Research Questions

In line with the above, we outline the following research questions: a. What are the most important subjective and objective quality attributes that contribute to users' satisfaction and loyal behaviour? b. How can these quality attributes be measured? In particular, are the existing measuring instruments suitable for evaluating the quality in use of Web 2.0 applications? c. Can these quality attributes be translated into a set of heuristics that would facilitate the assessment of Web 2.0 applications? d. Can these quality attributes be converted into a set of guidelines that would contribute to improved design of Web 2.0 applications and their testing? e. Which methods, techniques and procedures should constitute an evaluation methodology that simplifies an analysis and comparison of Web 2.0 applications?

Methodology

Our research is divided into three parts: theoretical background, pilot study and main research. Until now, the theoretical part and the pilot study have been completed. In the theoretical part, a literature review was prepared according to the methodology proposed by Webster and Watson [START_REF] Webster | Analyzing the past to prepare for the future: writing a literature review[END_REF]. An analysis of recent relevant research in the field of web quality and usability assessment resulted in a set of attributes that may have a significant role in the evaluation of the quality in use of Web 2.0 applications [START_REF] Orehovački | Proposal for a Set of Quality Attributes Relevant for Web 2.0 Application Success[END_REF]. Based on their theoretical similarities, the attributes were initially placed into six different categories: system quality, service quality, information quality, performance, effort, and acceptability. In addition, based on the type of the measuring instrument to be used for data collection (a questionnaire or a tool for logging actual use), the attributes were grouped into subjective and objective quality attributes. The validity and reliability of questionnaire items was evaluated according to the guidelines suggested by Straub et al. [START_REF] Straub | Validation Guidelines for IS Positivist Research[END_REF].

The aim of the pilot study was to test the suitability of the measuring instruments for evaluating the quality in use of Web 2.0 applications. The participants in the pilot study were students who used Web 2.0 applications to perform various educational activities. In the first experiment, two methods were employed in order to gather both quantitative (questionnaire) and qualitative (retrospective thinking aloud, RTA) data about the perceived quality of cloud based applications for collaborative writing [START_REF] Orehovački | Perceived Quality of Cloud Based Applications for Collaborative Writing[END_REF]. In the second experiment [START_REF] Orehovački | Exploring the Quality in Use of Web 2.0 Applications: The Case of Mind Mapping Services[END_REF], the research methodology was extended with the logging actual use method. The subjective assessment of Web 2.0 applications for mind mapping was conducted with the use of a questionnaire and RTA while the objective data about mouse movements, mouse clicks, keystrokes and time on task were gathered by means of the Mousotron tool [START_REF]Blacksun Software[END_REF]. An analysis of the data obtained from both experiments revealed a list of matching attributes that influence users' satisfaction and loyal behaviour regardless of the type of application used, including ease of use, effectiveness, reliability, interactivity, customizability, and navigability.

The remaining part of the research is structured as follows. Firstly, two different groups of experts (HCI researchers and web developers) will categorize quality attributes using the Q-sorting method [START_REF] Thomas | Q-Sorting and MIS Research: A Primer[END_REF]. Secondly, a scenario-based evaluation of Web 2.0 applications with different functionalities will be conducted. Data will be collected using a questionnaire (perceived quality in use) and a tool for logging actual use (estimated quality in use). Participants in the study will be recruited from different departments of two Croatian universities. The data obtained from the experts will be used in the development of a conceptual model that will be composed of two submodels: a measurement and a structural model, respectively. The former will take into account relationships between each latent variable (category) and corresponding manifest variables (attributes), while the latter will take into account the relationships among the latent variables. The validation of the conceptual model will be carried out with Partial Least Squares (PLS) path analysis in accordance with the catalogue of criteria discussed in [START_REF] Esposito | Handbook of Partial Least Squares: Concepts, methods, and applications[END_REF]. Measurement models will be assessed by means of content validity, indicator reliability, construct reliability, convergent validity and discriminant validity. On the other hand, the structural model will be evaluated in terms of its effect size and predictive validity. Based on the outcomes of the Q-sorting and the PLS analysis, a tree with logical relationships between categories and attributes will be specified and elementary criteria for each attribute will be defined. The final estimate (score) of quality in use will be calculated using a stepwise process of logic aggregation of preferences [START_REF] Dujmović | Preferential Neural Networks[END_REF].

Expected Contributions

The scientific contribution of the research is two-fold. From a theoretical perspective, the knowledge and experience in the field of quality and usability evaluation of Web 2.0 applications will be systematized. The most important quality attributes that significantly affect users' satisfaction and loyalty will be identified. Moreover, it will be determined whether the weight of each attribute varies depending on the Web 2.0 application type and the context of use.

From a practical point of view, the new methodology will offer a number of benefits. Firstly, it is expected to enable the evaluation of Web 2.0 applications using both subjective and objective measuring instruments, which may alleviate possible shortcomings of their separate use. Secondly, through the combination of several data collection methods, the process of detection of problems in Web 2.0 application usage will be facilitated and accelerated. It is noteworthy that, apart from the HCI experts and users, web developers (programmers, designers, architects) will also take part in the research (which so far, to our knowledge, has been rather rare). Thirdly, based on the results obtained from the practical use of the methodology, a new set of heuristics aimed for the evaluation of Web 2.0 applications will be created. In addition, the research will result in a series of guidelines and recommendations for the development of Web 2.0 applications. Finally, the afore-described methodology will enable the "transformation" of a lot of quantitative data into a single score, which would facilitate the analysis and comparison of evaluated Web 2.0 applications.


Luis A Rojas

José A Macías
email: j.macias@uam.es

End-User Support for Information Architecture Analysis in Interactive Web Applications

Keywords: Information Architecture, End-User Development, Analysis and Design of Interactive Web Systems

Information Architects analyze conceptual models and descriptions concerning non-functional requirements that will be later on used by Analysts and Software Engineers to design software artifacts. However, this flow of information is sometimes difficult to automate due to conceptual knowledge differences in the information processed by each expert. To facilitate this flow, in this paper we propose a CASE tool called InterArch. Our tool bridges the gap between both professionals, and it automatically generates UML diagrams for Analysts from the conceptual diagrams created by the Information Architect.

Introduction

The Information Architecture (IA) is defined as the science of structuring, organizing and managing information, where labeling, findability and usability are specifically important for a good information performance [START_REF] Erlin | The evolution of Information Architecture. Information Technology, ITSim[END_REF]. Its main objective is to facilitate, as much as possible, the comprehension and assimilation of the information [START_REF] Elaine | Information interaction: Providing a framework for information architecture[END_REF], as well as to execute tasks in user-defined information spaces [START_REF] Morville | Information Architecture for the World Wide Web. O'Reilly Media[END_REF].

The Information Architect attempts to find a bridge between the conceptual knowledge proposed by users in the problem domain and the design information that Software Engineers require to design the final interface in the solution domain. This gap frequently means that some degree of interoperability and alignment between the output generated by the Information Architect and the input expected by the Software Engineer is necessary in order to accomplish the whole software design. Furthermore, automating this flow of information could benefit from reducing both time and costs in software projects, also allowing each expert to focus on their own work and optimizing the transfer of knowledge among both professionals [START_REF] Macías | Providing end-user facilities to simplify ontology-driven web application authoring[END_REF].

In order to address this problem, we have designed a CASE tool called InterArch, which allows experts in the problem domain to focus on content development and browsing. This way, our tool automatically generates UML content classes for Software Engineers from the conceptual models crated by Information Architects, thus automatically specifying the right elements for the solution domain.

Proposed Solution

Most common products that Information Architects have to create to carry out the IA of an interactive web applications correspond to blueprints, wireframes, content models and controlled vocabularies [START_REF] Erlin | The evolution of Information Architecture. Information Technology, ITSim[END_REF][START_REF] Morville | Information Architecture for the World Wide Web. O'Reilly Media[END_REF]. From all this products, content models are particularly important for Analysts and Software Engineers, and they are very likely to be automatically processed in order to generate content classes and objects that define the solution in the application domain. This is the reason why we have focused on these essential products in favor of an explicit automation to provide useful input for the Software Engineer.

To address this challenge, our tool is based on two essential points: first, InterArch enables Information Architects to concentrate on conceptual-design tasks in the problem domain. Second, based on the initial analysis carried out by Information Architects, InterArch automatically generates UML diagrams for Analysts and Software Engineers, specifying elements that have a direct correspondence with the information content. UML information is generated in a transportable text-like format called XMI1 that improve interoperability and can be processed by a great deal of existing CASE tools in order to accomplish the rest of the phases in the software project lifecycle.

A CASE Tool for the Information Architect

InterArch comprises a set of processes that are responsible for the management and transformation of information models in a visual environment for the IA analysis. These processes include: visual modeling of the conceptual elements required by the information professionals, transformation of the visual model into an intermediate model, and textual-transportable generation of the analysis of the information using UML diagrams. In a nutshell, these processes aim to take the input -i.e., the visual diagrams created by the Information Architect, and generate the output comprising UML diagrams for Analysts and Software Engineers.

The main idea behind these architectural components is to enable Information Architect to work in the visual processing of diagrams in a transparent way, but also featuring an interpretation overlay that recognizes the different correlations between such analysis diagrams and the UML classes required by Software Engineers. The transformation of the visual model is achieved through a set of relations and association rules which are applied to the conceptual model in order to generate the corresponding UML diagrams in XMI format.

A Worked Example

In order to describe our tool in detail, we provide a specific example using InterArch.

Let us suppose that the Information Architect is working on a content model including information about the composition and prices of products in order to carry out the IA analysis of an on-line shop. This situation corresponds to the diagram depicted in Figure 1.

Fig.2. UML Class Diagram generated by InterArch

To generate UML diagrams based on IA diagrams, transformation rules are applied in order to find out meaningful relationships. Carrying on with the example (see Figure 1), element Component will be first generated as a main class, also considering the descendant elements that will be processed by applying the following rule: terminal elements, and direct descendants from the main element, will become attributes for class Component. If these elements also have descendants, they will directly become new classes related to Component. This rule is recursively applied for all descendant elements in order to generate new classes, attributes and relationships. This way the application of this rule generates, for instance, a class Component with five attributes: partNumber, partName, partType, description and price. As for the class methods, three methods for each attribute that represents an aggregate class are generated by default (get, set and new). Figure 2 shows the final visualization of the UML classes generated including all the elements.

Conclusion and Future Work

In this paper, we propose an approach that provides an automatic solution to bridge the gap between high-level conceptual representations of content and the UML analysis and design classes needed to implement such content.

Our research is based on the EUD (End-User Development) paradigm [START_REF] Klann | End-User Development. D1.1 Roadmap[END_REF][START_REF] Macías | Providing end-user facilities to simplify ontology-driven web application authoring[END_REF], where the main idea is to help end-users create or customize applications easily. More specifically, our work is based on EUSE (End-User Software Engineering), whose aim is to involve non-expert users, as often happens with Information Architects, in particular issues of the development process in software analysis and design [START_REF] Lieberman | End-User Development[END_REF].

As future work, we expect to provide new features, such as the generation and customization of rich design elements like design and content components. Also, we expect to carry out a usability evaluation, in order to study the trade-off between ease of use and expressiveness by involving professional Information Architects.

Figure 1

 1 depicts the user interface of InterArch, whose main parts are labeled with A, B and C. Part A includes a tool bar that implements functionalities concerning files, edition, format and style and others. Part B represents the main authoring environment used by the Information Architect. Finally, part C shows the icon library to enrich the visual composition of diagrams developed by the Information Architect.

Fig. 1 .

 1 Fig. 1. InterArch User Interface

XMI is the OMG-defined standard for the exchange of UML diagrams, www.omg.org.

Acknowledgements. The work reported in this paper is being supported by the Spanish Ministry of Science and Technology, project ID: TIN2008-02081/TIN, the Madrid Research Council, project ID: S2009/TIC-1650 and, together with the UAM, project ID: CCG10-UAM/TIC-5772.


Sandra Burri
email: burri@hum.aau.dk

Henrik Schärfe
email: scharfe@hum.aau.dk

Jens Vilhelm Dinesen
email: jdinesen@hum.aau.dk

Towards a Context Oriented Approach to Ethical Evaluation of Interactive Technologies

Keywords: Ethics, Persuasive Design, Løgstrup, PLOT, e-Learning, Learning Objects

This paper explores and develops the notion of applying the ethical perspective of Danish philosopher and theologian K.E. Løgstrup, when designing and developing interactive technologies. The ethical reflections presented in this paper are currently considered in the development of Persuasive Learning Designs within the EU funded PLOT project, thus enabling this paper to support the argumentation with a practical example of integrating ethical considerations into the different stages of a design process.

Introduction

This paper explores and develops the notion of applying the ethical perspective of Danish philosopher and theologian K.E. Løgstrup, when designing and developing interactive technologies. The paper builds on previous research, in which the relevance of Løgstrup's ontological approach to ethics has been established [START_REF] Gram-Hansen | Towards an Approach to Ethics and HCI Development, based on Løgstrup's Ideas[END_REF], and provides a practical example of participatory design where this particular approach to ethics appears to offer valuable philosophical insight and considerations.

Previous research has raised the argument that the often applied utilitarian and deontological evaluation methods are insufficient when evaluating interactive computer technologies, as they fail to include reflections regarding the social reality of the users and the context in which the technology is applied and fail to acknowledge the mutual ethical responsibility between the designer and the user. This is problematic as designers are not necessarily able to foresee all possible use scenarios and should as such not be held solely responsible for unethical consequences of applying a technology [START_REF] Albrechtslund | Ethics and Technology Design[END_REF][START_REF] Gram-Hansen | Persuasive Everyware -Persuasive Design Funderet i Kairos[END_REF] In order to meet these shortcomings, Gram-Hansen suggests that the ontological perspectives and reflections presented by K.E. Løgstrup may be a beneficial supplement to ethical evaluations of interactive computer systems [START_REF] Gram-Hansen | Towards an Approach to Ethics and HCI Development, based on Løgstrup's Ideas[END_REF].

Løgstrup finds, that ethics, rather than being based on reason, is founded in what he calls sovereign expressions of life, which includes benevolence, open speech, trust, love and compassion -in other words human features that are generally considered ethically praiseworthy. He furthermore argues that we are born into ethics as a result of the dependency which exists between humans. As soon as humans interact, they influence each other's lives, and it is by interaction that ethics and ethical responsibility emerges. Furthermore, Løgstrup stresses that the perception of ethics is based on the contextual reality of the individual, i.e. ethics is considered an intuitive result of human nature, rather than moral rule based on reason, and the distinction between ethical and unethical actions are dependent on the specific situation and the social reality of the people involved in the interaction.

Considering Løgstrup's ethics when evaluating interactive technologies is not unproblematic. Firstly because Løgstrup argues that the perception of the ethical action is based on the intuition and social reality of the person performing an actionmaking it impossible for others to evaluate the action. And secondly because the notions of ethics which are presented by Løgstrup, originate from reflections concerning humans who are physically located at the same place thus sharing a common understanding for the characteristics which define the specific context. The ability to interact through technology has ended the necessity of interacting parties actually meeting, and when the interaction takes place between the designer and the user, they will most often not be found at the same place. As a result, the ethical perspective presented by Løgstrup cannot stand alone in the evaluation of interactive technologies, but should be applied as a third perspective in collaboration with utilitarianism and deontology. Løgstrup's contribution serves as a context oriented perspective, providing reflections and discussions which are as essential in interaction through technologies as they are for physical interaction between humans. In particular, Løgstrup offers valuable viewpoints concerning key concepts such as trust, credibility and interaction.

Whilst acknowledging that Løgstrup's ethical reflections are not exclusively applicable as an evaluation method, this paper will argue that the inclusion of key concepts and notions presented by Løgstrup may be highly beneficial to the design process -particularly if the process includes elements of value sensitive design (VSD) and participatory design. In order to exemplify how Løgstrup's ethical perspectives may be included in a design process, a selection of key concepts and core notions are considered in practice in the development of Persuasive Learning Designs within the EU project PLOT.

Putting theory to practice in the EU project PLOT

The EU funded PLOT project (Persuasive Learning Objects and Technologies) was initiated in November 2010 and aims to develop a pedagogical framework for active engagement, based on persuasive design, as well as to demonstrate its value by creating tools and exemplars of adaptable, reusable learning resources. This pedagogical framework will incorporate persuasive design principles, which determine how to design ICT that can change people's behaviour and/or attitudes. The Persuasive Learning Designs on one hand incorporate known and well-tested didactic principles, and on the other hand offer implementation particularly designed to embody persuasive principles such as guided choices, simulations, competitions, and possibilities to share the experience with peers. The impact will be to generate more effective active e-learning resources and will give teachers the necessary tools to both create new and adapt existing resources to suit their needs. This will improve the quality of e-learning resources available for both teachers and students across [START_REF] Schärfe | [END_REF].

The PLOT partner group consists of designers, developers, experts in learning and in persuasive design, as well as representatives from the four project work cases. As such, the partner group consists of both technical experts and members with little or no technical proficiency. Within the development process, this causes some classical difficulties in relation to common language and common understanding of the work process. Amongst the challenges to be met within PLOT, is the development of Persuasive Learning Designs for each of the four work cases. Each work case represents different learning material and different challenges, and do as a result require individual attention and consideration if the learning designs are to comply with not only learning theory but also with the notion of persuasive technologies and persuasive design.

In order to acquire the necessary contextual information about the four cases, the PLOT partners were asked to participate in an Inspiration Card Workshop which was held during the Euro PLOT consortium meeting on May 10 th and 11 th 2011. The aim of the workshop was to create a social context in which the individual case representatives were given the opportunity to explain and elaborate upon their individual challenges in teaching and learning, and for the additional members of the consortium to ask questions and reflect upon the different case scenarios.

The workshop setup was inspired by previous work of Halskov and Dalsgaard [START_REF] Halskov | Inspiration card workshops[END_REF] and Davis [START_REF] Davis | Generating Directions for Persuasive Technology Design with the Inspiration Card Workshop[END_REF], but was executed in a narrower and more focused version by applying technology cards. These cards were primarily examples from the Design With Intent Toolkit, which was developed by Dan Lockton, which focuses entirely on intentional design in technologies. [START_REF] Lockton | Persuasive Technology in a Wider Context in Persuasive[END_REF] In practice, the members of the consortium were divided into two groups, which each had case representatives from two cases as well as partners representing design and development teams. Supported by the inspiration cards, each of the cases were explained and discussed. In order to ensure direction within the discussions, the groups where required to complete the workshop by creating a poster for each case which described one of the challenges they were facing, and a suggestion to its solution.

Workshop results

The notion of the workshop was to facilitate mutual understanding between the individual partners, which was not only vital to the case oriented development of Persuasive Learning Designs, but could also motivate a reciprocal responsibility between case representatives and project developers, that may be considered the very foundation of future ethical interactions.

During the workshop it became apparent that the approach did impose a greater mutual understanding between the members of the consortium, and that the inspiration cards served as inspiration during discussions as well as a mean to ensure that the topics discussed were the ones relevant to the development of persuasive learning designs.

More importantly however, the workshop constituted a contextual reality in which we as designers where able to include several of Løgstrup's key concepts in our development process. The workshop initiated interaction between developers and designers in a way which influenced the natural power balance between the participants and created a context in which terminology and professional background was less important compared to the ability to actively engage in discussion and idea development.

As mentioned, this particular approach is easily linked to the notions of VSD and participatory design, which are commonly credited as ways of ensuring the ethicality of the product being developed [START_REF] Davis | Design methods for ethical persuasive computing[END_REF]. However, by adding Løgstrup's approach to ethics to this established methodological perspective, designers and developers who initiate and engage in participatory design processes, are provided with a philosophical foundation for the ethical evaluation, as well as a number of key concepts to consider as the participatory activities are defined. Whether development participation consists of workshops, interviews or agile development methods, interaction, reciprocal responsibility and the perception of power balance are of vital importance, and may in all cases be supported and nuanced by considering the philosophical works of K.E. Løgstrup.


Dzmitry Aliakseyeu

Jon Mason

Bernt Meerbeek
email: bernt.meerbeek@philips.comh.a.v.essen

Harm Van Essen

Serge Offermans
email: s.a.m.offermans@tue.nl

Andrés Lucero
email: andres.lucero@nokia.com

User Interaction Techniques for Future Lighting Systems

Keywords: Lighting, User Interaction, LED, Smart lighting

LED-based lighting systems have introduced radically new possibilities in the area of artificial lighting. Being physically small the LED can be positioned or embedded into luminaires, materials and even the very fabric of a building or environment. Together with new functionality and flexibility comes complexity; the simple light switch is not anymore sufficient to control our light. This workshop explores new ways of interacting with light. The goal is to define directions for new forms of user interaction that will be able to support the emerging LED-based lighting systems.

Introduction

The Light Emitting Diode (LED) has caused a profound change within the lighting industry. This is due in part to the LED's key properties of being physically small, highly efficient, digitally controlled and soon, very cheap to manufacture. Being physically small the LED can be positioned or embedded into luminaires, materials and even the very fabric of a building or environment [START_REF] Price | Light Fantastic[END_REF]. The price to pay for all this functionality and flexibility is complexity. In the past, the single light bulb was controlled using a single switch; on and off. LED-based lighting systems can easily consist of hundreds separate light sources, with each source having many individually controllable parameters including colour, intensity, and saturation. With this high complexity, end-users cannot be expected to fully control all aspects of the lighting system. One direction that is being explored is to enrich lighting systems with sensor networks that will enable automatic lighting control that is based on contextual information [START_REF] Bhardwaj | Smart lighting using LED luminaries[END_REF]. However in many situations, such as setting up an atmospheric light, an explicit user interaction will still be required. Moreover, as functionality and complexity of light systems grow, the mapping between the sensors data and the desired light outcome will become fuzzy and will require an explicit user interaction for fine tuning the outcome or for adjusting the mapping between sensor input and light output. Thirdly, explicit interaction can be desired to allow users to feel in control while interacting with intelligent lighting systems. The light switch therefore in many situations will need to be replaced by novel forms of interactions that offer richer interaction possibilities such as tangible, multi-touch, or gesture-based user interfaces. As proliferation of LED light continues, it becomes more important to go beyond scattered design efforts [START_REF] Bhardwaj | Smart lighting using LED luminaries[END_REF][START_REF] Lucero | Reducing Complexity of Interaction with Advanced Bathroom Lighting at Home. I-COM[END_REF] and systematically study user interaction with emerging lighting systems. The goal of this workshop is to take the first steps in this direction.

Goals of the workshop

The focus of this workshop is on formulating key research challenges for user interaction with future lighting systems, creating initial design guidelines, and proposing novel interaction techniques for these systems. The goals of the workshop: 1. Make a first step toward expanding the design space of interactive technologies to include new forms of decorative, ambient, and task lighting. 2. Identify key challenges of UI for controlling new forms of lighting systems. 3. Establish a link with existing interaction paradigms that can be (re-)used for control of future lighting systems. During the workshop, we would like to address and discuss the following questions:  What design opportunities for interactive technology exist in the context of the new forms of lighting?  What forms and types of (existing) interaction are suited for emerging lighting systems (in particular tangible, gesture and multi-display interaction techniques)?  What forms of interaction are best suited for a global control (e.g. atmosphere)

and what for a point control (e.g. task lighting)?  How to balance between explicit user control and internal system control?  How to use a lighting infrastructure as ambient displays and how to combine it with its primary function i.e. illumination?  What is the impact of the proposed interaction techniques for complex lighting systems in other domains? What is the generalizability of these techniques? To address the workshop questions we are inviting researchers to submit position papers that discuss or present new forms of interaction techniques for lighting. This topic deals with the research and design of new forms of user interaction or adaptation of existing ones to emerging lighting systems. The topic should attract researchers and designers working on new forms of interaction, LED lighting, smart lighting systems and who are interested in exploring UI for new emerging types and forms of luminaires and lighting systems.