The rapid transformation of the industrial sector requires strategies to integrate digitalization and monitoring. While these advancements promote data-driven optimization of manufacturing processes, they raise concerns regarding employee data privacy. This study shifts the focus from the prevalent technological perspective to the perspectives of employees, critically examining the factors influencing their willingness to share data. Employing a Choice-Based Conjoint Analysis with n = 132 participants, our research suggests a strong preference for exclusive control over access to personal data, particularly health-related information, indicating that privacy concerns typically eclipse the advantages offered by data sharing in the workplace. Using latent class analysis, we distinguish between two employee groups characterized by distinct privacy attitudes: “Data Protectors” and “Team Players.” These findings underline the need to further investigate the influence of employee diversity, including demographics, attitudes, and job functions, to effectively optimize communication strategies and address diverse privacy expectations.

The consequences of an aging society pose one of the major challenges of our time. Technology solutions that alleviate the strain on the overburdened healthcare system can effectively support individuals needing assistance. Still, technology acceptance is a crucial variable in understanding what drives users to utilize such applications. This study examined the role of trust and privacy in the accepted use of ambient technologies for health-related purposes. Using an online survey we collected data from N = 102 respondents. Findings revealed that participants are willing to use ambient technology for health. Benefits and barriers are traded off, whereby the advantages outweigh the perceived barriers. Trust conditions to be fulfilled include data security, technical soundness, and health-related aspects. Having control over personal information results as the most important privacy aspect, followed by the supervision of social contacts. Regression analyses revealed perceived motives and barriers, technical soundness, and health-related trust to be significant predictors of acceptance.

Many initiatives aim at answering the challenges of the fourth industrial revolution (Industry 4.0). A key aspect of these initiatives is the connectivity of the different industrial entities. Communication and information exchange between entities usually flows in two dimensions; a vertical one, that spans the different levels of abstraction within the company, and a horizontal one connecting the different entities in the supply chain. In contrast, the Internet of Production (IoP) presents the World Wide Lab (WWL) allowing an extra dimension of communication, which we call the cross-company dimension. Hence, the WWL integrates the different entities within and across potentially competing labs and companies. The WWL leverages and aggregates accessible production data fostering an exchange of information, that prevents redundant experimentation and increases quality of data-driven models by including data from diverse manufacturing settings. This paper discusses work done towards this vision and technical, economic, social, legal, and ethical challenges the WWL faces and provides a roadmap towards infrastructuring the WWL.

Research on video-based Ambient Assisted Living (AAL) technologies is increasing due to their potential of providing abundant sensory information about a person in need of support. Acceptance of these visual sensors is limited among potential users as perceptions of barriers persist, most importantly privacy concerns. The current study aimed to investigate potential users’ behavioural intention to use video-based AAL and their evaluations of relevant benefits and barriers during activities of daily living in their own homes. Special focus was on exploring the influences of individual differences (demographics and psychometrics) on evaluation patterns. In total, evaluations of 122 participants (age range: 17-81 years) were assessed through an online survey. The results are in line with previous findings on perceived benefits and barriers and their relevance to the acceptance of AAL technology. Beyond that, the results revealed significant relationships and impacts of individual differ ences, i.e., privacy perception, self-consciousness, and body consciousness, on the perceived barriers and indirectly also on the acceptance of video-based AAL technology. Further, three clusters of potential users were identified, differing significantly in their evaluation of video-based AAL technology as well as in their individual characteristics, i.e., privacy perception and self-consciousness. The findings of this study are useful to derive recommendations for user-tailored development and communication of video-based AAL technology.

The vision of the Internet of Production (loP) is focused on optimizing manufacturing processes, with the help of Industry 4.0 technologies (14Ts). However, considering global megatrends such as climate change and the need to achieve the Sustainable Development Goals (SDGs), it is a growing imperative for the manufacturing industry to become more sustainable. This opens the door to transforming the IoP into an Internet of Sustainable Production (loSP). Accordingly, this paper proposes a novel four-step loSP-framework that establishes an Information System (IS) allowing researchers and practitioners to acknowledge and adapt to the interconnected nature of sustainability. Further, to test its applicability, an inter- and cross-disciplinary perspective is adopted to illustrate case-related challenges, opportunities, and pathways - revealed by the proposed framework - in the example of a digital economy for sustainability data, strategic design of global production networks, human-robot collaboration, digital photonic production, and the textile industry. Together, the framework demonstrates the usefulness of generating holistic information on the interconnected nature of sustainability derived from process-specific and contextualized data, while simultaneously assessing the framework's utilization for sustainability, as well as the sustainability of its use.

Addressing demographic change, assistive technologies are developed to support people in need of care. So far, little is known about the impact of context-related individual perceptions on the adoption of such technologies. The present study investigates the extent of relationships between (a) aging-, care-, and health-related perceptions and (b) the perception and acceptance of using assistive technologies. In an online survey (N = 1123), the participants assessed individual perceptions of aging, care, health, perceived benefits, barriers, and acceptance of an assistive system. Using structural equation modeling the relationships between individual attitudes and acceptance were investigated. Results revealed that perceptions of care were related to acceptance, perceived barriers, and benefits. Positive perceptions of aging were related to perceived benefits and care. Moreover, perceived vitality correlated with perceptions of aging and perceived benefits. The study provided insights into individual perceptions of aging, care, and health as well as their relationships with assistive technology’s acceptance.

Smart technologies for aging-in-place address the desire of older adults to live at home independently. Concurrently, they can support the challenged healthcare systems in times of demographic change. Much has already been understood about which factors influence the technology acceptance by future users. Thereby, privacy concerns have been highlighted as a decisive barrier. However, less is yet known about how acceptance is influenced: the central workings of acceptance genesis, the weighing between barriers and benefits and resulting trade-offs have only been focused in very few studies. To gain a deeper understanding of the weighing and trade-offs between privacy barriers and security benefits, an Adaptive Choice-Based Conjoint analysis was carried out using the example of emergency detection technologies (n = 274). The results indicate that if smart technologies offer life-saving security benefits in situations of need, privacy concerns are outweighed. The most important factor for the acceptance decision is the reliability followed by the fall risk. Privacy-related aspects were less important for acceptance decisions. Additionally, the study reveals important data on preferences for system characteristics as well as acceptance thresholds—non-negotiable no-go’s or must-haves. This information helps to understand users’ desires in order to tailor smart technologies to their specific needs.

Digital shadows play a central role for the next generation industrial internet, also known as Internet of Production (IoP). However, prior research has not considered systematically how human actors interact with digital shadows, shaping their potential for success. To address this research gap, we assembled an interdisciplinary team of authors from diverse areas of human-centered research to propose and discuss design and research recommendations for the implementation of industrial user interfaces for digital shadows, as they are currently conceptualized for the IoP. Based on the four use cases of decision support systems, knowledge sharing in global production networks, human-robot collaboration, and monitoring employee workload, we derive recommendations for interface design and enhancing workers’ capabilities. This analysis is extended by introducing requirements from the higher-level perspectives of governance and organization.

Ambient Assisted Living (AAL) technologies have a high potential to combat healthcare challenges while supporting older adults to live independently at their own home. Despite the general positive uptake of such technology, perceptions of barriers of acceptance persist, a major one regards privacy. With an explorative qualitative approach, the current study aimed at investigating participantsc̀ognitive representations of a scenario in which AAL is installed in the own home as a support at an older age. Special focus was on eliciting participantsìmplications for privacy in this scenario and to understand the individual requirements of using AAL technology at home. Opinions of 12 participants (age range: 23-81 years) from Germany and Switzerland were assessed through semi-structured interviews. The paper presents descriptive results and emerging themes of the mapping approach. The results show the usefulness of the method to understand thought processes of potential users regarding pri vacy preferences and technology usage. Findings might be useful to inform technical designers as well as lawmakers to consider these usage requirements during technology or law development.

Due to a demographic change of the society, health care worker shortage and rising co- and multimorbidity within older adults, constant care at home and at care facilities face a difficult task to combat these challenges. Medical AAL technology offers many opportunities to relieve health care workers and assist older adults with difficulties in managing activities of daily life (ADL). This study has adopted an exploratory interview method to explore the users’ perceptions of trust in the medical context and specifically, related to medical AAL technologies. Eleven participants ranging from 20 years to 87 years old (M = 52.27; SD = 24.2) were interviewed and, in line with previous results in the literature, results revealed three categories of influences, namely user factors, technology factors, and context factors. This implies a network of trust dependent on various external and internal influences. These findings have practical implications for clinicians, developers, policy makers and legal professionals.

With the advent of automation in road traffic, vehicle interaction design is undergoing a major shift and facing new challenges. In this paper, we adopted a user-centered design approach to identify suitable interface types for the interaction between automated light vehicles for urban last-mile deliveries and their human operator. In an exploratory co-creation workshop, we first identified possible interface types with laypeople and logistics employees (N=8). Based on the workshop insights, we surveyed user acceptance of various interface options (e.g., app, voice, and gesture control), the situation- and user-dependency of interface acceptance, and the users’ motivations for preferring specific interface types (online survey study: N=188). The analysis revealed that ease of use, road safety, and compatibility were the most mentioned reasons for preferring a particular interface type. Additionally, results showed that app and voice control were, on average, perceived as most desirable. However, none of the queried interface types was assessed as a perfect fit for each interaction situation and user.

The ongoing digitization and novel smart technologies can deliver enormous benefits to society and individuals. However, smart services often require the vast collection of data conflicting with users’ privacy. The integration of privacy concerns into acceptance research is needed to portray and predict user decisions in smart technologies. To allow a privacy-integrated prediction of users’ technology acceptance, we apply the privacy calculus theory to adoption behavior. We test the new model in three usage contexts, autonomous driving (transportation), activity trackers (fitness), and cardiac device remote monitoring (medical treatment). Using an online questionnaire, 624 German participants evaluated all three technologies. The model fits well in all contexts, although also context-related differences in the weighing of perceived benefits and privacy concerns showed. It is concluded that the trade-off between perceived benefits and privacy concerns is a central keystone not only for the willingness to disclose information but also for technology acceptance.

The Industrial Internet-of-Things (IIoT) promises significant improvements for the manufacturing industry by facilitating the integration of manufacturing systems by Digital Twins. However, ecological and economic demands also require a cross-domain linkage of multiple scientific perspectives from material sciences, engineering, operations, business, and ergonomics, as optimization opportunities can be derived from any of these perspectives. To extend the IIoT to a trueInternet of Production, two concepts are required: first, a complex, interrelated network of Digital Shadows which combine domain-specific models with data-driven AI methods; and second, the integration of a large number of research labs, engineering, and production sites as a World Wide Lab which offers controlled exchange of selected, innovation-relevant data even across company boundaries. In this article, we define the underlying Computer Science challenges implied by these novel concepts in four layers:Smart human interfacesprovide access to information that has been generated bymodel-integrated AI. Given the large variety of manufacturing data, newdata modelingtechniques should enable efficient management of Digital Shadows, which is supported by aninterconnected infrastructure. Based on a detailed analysis of these challenges, we derive a systematized research roadmap to make the vision of the Internet of Production a reality.

Digital Shadows as the aggregation, linkage and abstraction of data relating to physical objects are a central vision for the future of production. However, the majority of current research takes a technocentric approach, in which the human actors in production play a minor role. Here, the authors present an alternative anthropocentric perspective that highlights the potential and main challenges of extending the concept of Digital Shadows to humans. Following future research methodology, three prospections that illustrate use cases for Human Digital Shadows across organizational and hierarchical levels are developed: human-robot collaboration for manual work, decision support and work organization, as well as human resource management. Potentials and challenges are identified using separate SWOT analyses for the three prospections and common themes are emphasized in a concluding discussion.

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An aging society characterized by rising numbers of people in need of assistance and care poses tremendous challenges for care services, hospitals, families, and the whole society. Using assisting technologies represents a potential support and relief for aged individuals, people in need of care, and their caregivers. Despite their advantages, existing concerns and barriers regarding these technologies (e.g., data security, privacy) impede the user’s acceptance. Beyond that, acceptance and the perception of technology-related benefits and barriers depend on the diversity of the future users: e.g., their cultural background as well as attitudes toward aging and care. Applying an online questionnaire, this article aims at an exemplary comparison of Turkish and German participants’ perceptions and acceptance of using lifelogging cameras as technical application. This study investigates how participants of the two countries handle and evaluate the topics aging and care, and to what extent these attitudes are connected with the perception and acceptance of assisting technologies. Findings revealed significant differences between Turkish and German participants’ attitudes, their perceptions of benefits and barriers as well as acceptance of lifelogging cameras. The results indicated that assisting technologies have to be tailored specifically to the respective users.

Increasing numbers of older individuals in the societies pose great challenges for countries affected by the demographic change. The rapid development in the technological sector, on the other hand, enables various applications to make everyday life easier for older and disabled people and to maintain their autonomy for longer. This study examines the acceptance and privacy perceptions of a video-based technology for lifelogging in home environments among German and Turkish users, using a multi-method empirical research approach. Results expose an overall differing acceptance of using lifelogging cameras between German and Turkish participants and suggest that the consideration of the varying culture-bound demands is necessary. The findings of this study support the understanding of requirements for a successful implementation of a video-based assistive technology in private environments to optimally address the needs of the future users, drawing attention to the important cultural influences that affect its acceptance.

Lifelogging technologies have the potential to facilitate and enrich the everyday life of younger as well as older people. On the one hand, tracking and logging of data about activities and behavior support an active lifestyle. On the other hand, tracking medical data and movements support increasing safety by detecting, e.g., emer-gencies or falls. From a technical perspective, a variety of technologies enable lifelogging and are already available on the market. Instead, there is very little knowledge about the perception and acceptance of lifelog-ging technologies from users’ socio-ethical perspective. Hence, this paper presents research results from four online survey studies (n = 1107) aiming at covering a broad range of lifelogging applications and reaching di-verse target groups. Being based on insights gathered from the quantitative data collection, this paper derives guidelines for integrating ethical and social perspectives in lifelogging technology development and emphasiz-es gaps within the research landscape regarding its perception and acceptance.

Ambient Assisted Living (AAL) Technologies may help address the challenges that the ageing populations pose on the health care systems by supporting older adults in ageing-in-place, improving independence, and quality of care.Technology acceptance by the potential users and particularly privacy concerns are decisive obstacles to the widespread use of AAL.In order to examine privacy perceptions in detail, 86 participants (50% older than 50 years) evaluated AAL technologies and privacy concerns in a questionnaire approach.Additionally, with Maximum Difference Scaling the importance of AAL system characteristics to privacy perceptions by the users was investigated.Overall, the attitude towards AAL is positive, privacy concerns regarding the misuse of data, feeling of surveillance, and obtrusiveness of the technology are prevalent but not tremendous.Who has access to the data is by far the most important characteristic of an AAL system for the users' privacy.Prominence of the system, sensor location, and sensor types are least important.The results contribute an important understanding of how AAL technologies need to be designed to respect users privacy.

Shifts in demographic developments have led to changed needs and requirements in healthcare.Rising life expectancy and improved medical healthcare enable a more independent and healthier lifestyle of (older) persons, but also changes expectations and perceptions of aging, and health-supporting technologies.Knowledge about attitudes towards aging, medical assistive technologies, and impacting user factors (especially age and health status) is limited with regard to a broad sample of participants.In the present study (N=585), we therefore examined in an online-survey current attitudes towards aging and quality of life in older age, as well as perceptions and acceptance of health-supporting technologies, taking age and health status as user factors into account.Results revealed significant effects of age and health condition on the perception of life quality in older age.In addition, positive perceptions of aging, technology acceptance, as well as benefits and barriers were significantly influenced by the respondents' age.In contrast, health status significantly affected the negative perceptions of aging.Under impacts of age and health condition as user factors, results of the study allow a deeper understanding of changing patterns of perceived aging and prevailing opinions regarding acceptance of medical technology.

Industry 4.0 and the Internet of Production can increase efficiency and effectiveness of workflows in manufacturing companies and production networks. Despite ubiquitous automation, people are essential in socio-technical cyber-physical production systems due to unique cognitive capabilities, as final arbitrators, or for ethical and legal reasons. However, the design of interfaces between the human-in-the-loop and production systems poses challenges not yet been sufficiently elaborated in research and practice. We present two behavioural studies in the context of inter-company collaboration that show why considering the human-in-the-loop is crucial: The first study shows that information complexity and individual differences shape the overall decision quality. With increasing information complexity, the decision speed decreases and the decision accuracy descends. Consequently, a fine balance between necessary, abundant, and superfluous information must be found. The second experiment studies human decision making in complex environments using a business simulation. We found that correct decision aids can augment the human-in-the-loop's decision making and that these can increase usability, trust, and proft. Yet, incorrect decision support has the opposite effect. Guidelines for designing socio-technical cyber-physical production systems and a research agenda conclude this article.

Today more and more people use social networks and so the differences in personalities of users become more diversified. The same holds true for available news content. To test if regular news and fake news are distributed similarly and to what extent this depends on the personality and behavior of individuals, we conducted a mixed-method study. Through an online questionnaire we measured personality traits of individuals in social networks, how they behave, and how they are connected to each other. Using this data, we developed an agent-based model of an online social network. Using our model, an average of 92% of regular news and 98% of fake news were disseminated to the whole network. Network density turned out to be more important for dissemination than the differences in personality and behavior of individuals. Thus the spread of fake news can not only be addressed by focusing on the personality of individual users and their associated behavior. Systemic approaches---integrating both human and algorithm---must be considered to effectively combat fake news.

Connected autonomous driving can be a key for safety enhancement in road traffic and long-term reduction of driver-induced accidents with personal injury.Though, its acceptance is challenging, because of perceived restrictions on data security and privacy concerns.Hence, in this study, the focus was on users' perception of data privacy in autonomous and connected driving.For this purpose, a two-tiered research approach was conducted, based on semi-structured interviews (N=7) and an online questionnaire (N=100).Special attention was given to data storage and processing, data distribution, as well as personal usage purposes as predictors for the use intention.Results showed that the driver was most likely accepted as data decision maker, whereas the own car was preferred as data receiver.Besides, evaluation profiles indicated user diverse attitudes concerning the willingness to use autonomous driving regularly.These study outcomes contribute to a deeper understanding of user requirements in the context of mobility acceptance.

Due to the ageing population healthcare systems face monumental economic and social challenges. To respond to them, e-Health technologies and services are developed that seek to improve the quality of care and to support the monitoring and management of chronic diseases. One decisive factor for the widespread use of these technologies is user acceptance. As many e-Health technologies are essentially based on the storage, analysis, and transmission of large amounts of health-related data, privacy concerns can be a serious impediment to the successful adoption. However, privacy concerns are not included in traditional technology acceptance models. In this study, the impact of privacy concerns on the acceptance of e-Health technologies is studied. Also benefits and the formation of privacy concerns through trust in data protection, perceived data sensitivity, and the individual disposition to value privacy are examined. N = 253 participants with chronic health conditions evaluated two exemplary e- Health technologies: fitness trackers and remote monitoring of implanted cardiac devices. Structural equation modelling shows that privacy concerns are indeed an important barrier to the adoption of e-Health technologies and are influenced by the perceived data sensitivity, trust in data protection, and the individual disposition to value privacy. Users' privacy perceptions and concerns should be taken into account when designing e-Health technologies.

With the advent of artificial intelligence (AI) methods, smart decision support systems (DSSs) are becoming ubiquitous. Such systems help reduce complexity for operators by automating data integration tasks and recommending actions. However, these systems are sometimes flawed. It is not sufficiently understood whether, when and why operators comply with such systems in erroneous or correct cases. We empirically investigate compliance with correct and defective DSSs, the influence of correct and erroneous DSS's on performance and subjective factors related to compliance. In the study, a business game was used as an experimental setting in which 40 users took part. The impact of system correctness on user acceptance, trust, compliance and overall performance was investigated. The results show that the defective system reduces trust in automation (−47%), reduces usefulness (−58%), reduces acceptance (−62%) and reduces overall performance (−32%). Overall, the defective system was less user-friendly (−27%). Nevertheless, users who rated the system's usability higher, outperformed users who rated it lower. Usability is therefore an intermediary that compensates for the negative influence of erroneous DSSs.

The use of recommendation systems is widespread in online commerce. Depending on the algorithm that is used in the recommender system different types of data are recorded from user interactions. Typically, better recommendations are achieved when more detailed data about the user and product is available. However, users are often unaware of what data is stored and how it is used in recommendation. In a survey study with 197 participants we introduced different recommendation techniques (collaborative filtering, content-based recommendation, trust-based and social recommendation) to the users and asked participants to rate what type of algorithm should be used for what type of product category (books, mobile phones, contraceptives). We found different patterns of preferences for different product categories. The more sensitive the product the higher the preference for content-based filtering approaches that could work without storing personal data. Trust-based and social approaches utilizing data from social media were generally rejected.

In virtual environments, the space that can be explored by real walking is limited by the size of the tracked area. To enable unimpeded walking through large virtual spaces in small real-world surroundings, redirection techniques are used. These unnoticeably manipulate the user's virtual walking trajectory. It is important to know how strongly such techniques can be applied without the user noticing the manipulation-or getting cybersick. Previously, this was estimated by measuring a detection threshold (DT) in highly-controlled psychophysical studies, which experimentally isolate the effect but do not aim for perceived immersion in the context of VR applications. While these studies suggest that only relatively low degrees of manipulation are tolerable, we claim that, besides establishing detection thresholds, it is important to know when the user's immersion breaks. We hypothesize that the degree of unnoticed manipulation is significantly different from the detection threshold when the user is immersed in a task. We conducted three studies: a) to devise an experimental paradigm to measure the threshold of limited immersion (TLI), b) to measure the TLI for slowly decreasing and increasing rotation gains, and c) to establish a baseline of cybersickness for our experimental setup. For rotation gains greater than 1.0, we found that immersion breaks quite late after the gain is detectable. However, for gains lesser than 1.0, some users reported a break of immersion even before established detection thresholds were reached. Apparently, the developed metric measures an additional quality of user experience. This article contributes to the development of effective spatial compression methods by utilizing the break of immersion as a benchmark for redirection techniques.

We investigate priming and anchoring effects on perceptual tasks in visualization. Priming or anchoring effects depict the phenomena that a stimulus might influence subsequent human judgments on a perceptual level, or on a cognitive level by providing a frame of reference. Using visual class separability in scatterplots as an example task, we performed a set of five studies to investigate the potential existence of priming and anchoring effects. Our findings show that-under certain circumstances-such effects indeed exist. In other words, humans judge class separability of the same scatterplot differently depending on the scatterplot(s) they have seen before. These findings inform future work on better understanding and more accurately modeling human perception of visual patterns.

This paper presents the results of an online questionnaire (N=130) focusing on the impact of initial information for novel systems in two different automation levels. Willingness to share data and privacy concerns were compared between partial and conditional automation. With initial information on system limits manipulated between participants, differences in a priori attitudes and information relevance were analyzed. General attitude towards automation was positive. Willingness to share data when using automation was independent of ADAS experience and automation level. All driver-related data were not considered as sharable. Information relevance was highest for information on the anticipation of take-over situations, with information on certainty of successful situation management being significantly more important if system limits were unspecific. Results provide input for studies analyzing the influence of initial information and online information on take-over performance as well as on willingness to share data when receiving higher levels of automation in return.

Ubiquitous computing strives to reach the calm computing state where sensors and actuators disappear from the foreground of our surroundings into the fabric of everyday objects. Despite the great progress in embedded technology, artificial interfaces, such as remote controls and touch screens, remain the dominant media for interacting with smart everyday objects. Motivated by recent advancements in smart textile technologies, we investigate the usability and acceptance of fabric-based controllers in the smart home environment. In this article we describe the development and evaluation of three textile interfaces for controlling a motorized recliner armchair in a living room setting. The core of this contribution is the empirical study with twenty participants that contrasted the user experience of three textile-based interaction techniques to a standard remote control. Despite the slightly lower reliability of the textile interfaces, their overall acceptance was higher. The study shows that the hedonic quality and attractiveness of textile interfaces have higher impact on user acceptance compared to pragmatic qualities, such as efficiency, fluidity of interaction, and reliability. Attractiveness profits from the direct and nearly invisible integration of the interaction device into textile objects such as furniture.

This work aims at an evaluation of vehicle-to-infrastructure (V2X)-technology through the users' perspective. The technical opportunities of connected vehicles are affected by the acceptance of the technology and possible draw-backs on the privacy and data-security side. With a three-tiered research approach, this work identified beforehand argument lines in focus group discussions, which enabled a quantitative approach to evaluate positively and negatively perceived features of V2X-technology. Also gender related differences can be displayed. Further, the results of the second quantitative study indicate that although users who already have experience with driver assistance systems are more willing to share (personal) data to use V2X-technology, the overall sample is very reserved with respect to sharing driver-related data. Future research on user diversity and cultural differences is outlined.

How can you discover something new, that matches your interest? Recommender Systems have been studied since the 90ies. Their benefit comes from guiding a user through the density of the information jungle to useful knowledge clearings. Early research on recommender systems focuses on algorithms and their evaluation to improve recommendation accuracy using F-measures and other methodologies from signal-detection theory. Present research includes other aspects such as human factors that affect the user experience and interactive visualization techniques to support transparency of results and user control. In this paper, we analyze all publications on recommender systems from the scopus database, and particularly also papers with such an HCI focus. Based on an analysis of these papers, future topics for recommender systems research are identified, which include more advanced support for user control, adaptive interfaces, affective computing and applications in high risk domains.

The paper will show, how different types of users are evaluating privacy and data security differently according to contextual differentiating traffic situations. The focus is hereby on an analysis of user types to see, if general attributes towards data capture can be identified. User requirements are investigated in age, gender, experience with driver assistance systems and technical affinity. Several significant effects like the influence of prior experience increasing the willingness to share data in an traffic optimizing scenario could be revealed. But results show also an undeniable reluctance towards sharing private data with other traffic participants or companies. Traffic management such as police or the infrastructure itself are however entrusted with various personal information and data.

In mobile augmented reality (AR) applications, highly complex computing tasks such as position tracking and 3D rendering compete for limited processing resources. This leads to unavoidable system latency in the form of temporal delay and reduced display update rates. In this paper we present a user study on the influence of these system parameters in an AR point'n'click scenario. Our experiment was conducted in a lab environment to collect quantitative data (user performance as well as user perceived ease of use). We can show that temporal delay and update rate both affect user performance and experience but that users are much more sensitive to longer temporal delay than to lower update rates. Moreover, we found that the effects of temporal delay and update rate are not independent as with longer temporal delay, changing update rates tend to have less impact on the ease of use. Furthermore, in some cases user performance can actually increase when reducing the update rate in order to make it compatible to the latency. Our findings indicate that in the development of mobile AR applications, more emphasis should be put on delay reduction than on update rate improvement and that increasing the update rate does not necessarily improve user performance and experience if the temporal delay is significantly higher than the update interval.

Over the last years, public transport has become both more prominent and more diverse. Because of the complex structure of today’s public transport networks, an electronic guidance is effectively required. Usually different transport modalities and service providers offer their own application to which the traveler has to adapt after changing between services. Additionally a current trend in mobile applications is the customization of GUI elements which leads to appealing looks but usually also to cluttered presentation of information. Both these problems cause a high cognitive stress on the traveler using the mobile application, especially while conducting other activities at the same time. Our approach to mitigate these issues is to create a mobile application applying the Gamification principle Cascading Information Theory to simplify the usage and additionally to use a back-end which allows to integrate data from various services hereby unifiying the presentation. A prototype of the application was evaluated in an initial user test for comparing our approach to the most popular mobile travel application in Germany.

Journal Article Evaluation of a Mobile Projector-Based Indoor Navigation Interface Get access Ming Li, Ming Li * 1Computer Graphics Group, RWTH Aachen University, Aachen, Germany *Corresponding author: [email protected] Search for other works by this author on: Oxford Academic Google Scholar Katrin Arning, Katrin Arning 2Human Computer Interaction Center, RWTH Aachen University, Aachen, Germany Search for other works by this author on: Oxford Academic Google Scholar Oliver Sack, Oliver Sack 2Human Computer Interaction Center, RWTH Aachen University, Aachen, Germany Search for other works by this author on: Oxford Academic Google Scholar Jiyoung Park, Jiyoung Park 3Ewha Womans University, Seoul, Korea Search for other works by this author on: Oxford Academic Google Scholar Myoung-Hee Kim, Myoung-Hee Kim 3Ewha Womans University, Seoul, Korea Search for other works by this author on: Oxford Academic Google Scholar Martina Ziefle, Martina Ziefle 2Human Computer Interaction Center, RWTH Aachen University, Aachen, Germany Search for other works by this author on: Oxford Academic Google Scholar Leif Kobbelt Leif Kobbelt 1Computer Graphics Group, RWTH Aachen University, Aachen, Germany Search for other works by this author on: Oxford Academic Google Scholar Interacting with Computers, Volume 26, Issue 6, November 2014, Pages 595–613, https://doi.org/10.1093/iwc/iwt053 Published: 06 November 2013 Article history Received: 12 January 2013 Revision received: 09 September 2013 Accepted: 16 September 2013 Published: 06 November 2013

Location-based services, which can be applied in navigation systems, are a key application in mobile and ubiquitous computing. Combined with indoor localization techniques, pico projectors can be used for navigation purposes to augment the environment with navigation information. In the present empirical study (n = 24) we explore users' perceptions, workload and navigation performance when navigating with a mobile projector in comparison to a mobile screen as indoor navigation interface. To capture user perceptions and to predict acceptance by applying structural equation modeling, we assessed perceived disorientation, privacy concerns, trust, ease of use, usefulness and sources of visibility problems. Moreover, the impact of user factors (spatial abilities, technical self-efficacy, familiarity) on acceptance was analyzed. The structural models exhibited adequate predictive and psychometric properties. Based on real user experience, they clearly pointed out a) similarities and device-specific differences in navigation device acceptance, b) the role of specific user experiences (visibility, trust, and disorientation) during navigation device usage and c) illuminated the underlying relationships between determinants of user acceptance. Practical implications of the results and future research questions are provided.

This paper describes the first results on a sensor floor, which can be integrated in home environments to assist old and frail persons living independently at home. The sensor floor works with a dense array of piezo elements. Its purpose is not only to monitor the inhabitant's position within the room but also to analyze impact patterns for later activation of stable rescue procedures in case of fall or other emergency events. Algorithms were developed to gain information on steps of persons in the room from the piezo impulses. The sensors are invisibly integrated in the room's floor, which is part of a living lab (the Future Care Lab) developed and built within the eHealth project at RWTH Aachen University.

The present study examined the PDA menu navigation performance of younger and older adults. The research focus was directed to the understanding of the combination and interaction of user characteristics with PDA menu navigation performance. In order to detail individual factors that influence user's performance, users' age, spatial ability, verbal memory, the confidence to use technical devices and computer-expertise were studied and related to performance outcomes. Younger and older adults, experienced with the usage of different technical devices, but PDA novices, had to complete four common tasks in the digital diary of an emulated PDA and users' effectiveness and efficiency were surveyed. Even though the users of both age groups had a comparably high computer experience, participants had considerable difficulties to solve the PDA tasks successfully. Especially older adults were strongly disadvantaged when navigating through the PDA menu. Among the user characteristics which were revealed to be essential for performance, spatial abilities were the best predictor to explain PDA performance. In addition, an adequate mental representation of the PDA data structure was decisive for navigation performance, especially in the older adult group.

This paper investigates the feasibility and usefulness of completely icon-based menus in mobile devices. The underlying research was arranged in four steps: (1) Employing the sign production method, users' prototypic mental concepts for the pictorial representation of verbal menu terms were obtained. (2) Having selected and implemented the most prototypic ideas their potential was evaluated in the second step using the matching and the naming method. (3) In the third step an icon-based menu was constructed, programmed and implemented. (4) Finally, the utility of this prototype vis-a-vis a text-based menu was investigated on an experimental basis in a menu search task. The icon- based menu is shown to produce a significantly higher learnability thus outweighing initial differences. In general, results demonstrate that icon-based menus are basically viable and successfully applicable, if a users-centered procedure is pursued and if icons represent prototypical semantic knowledge.

Prior computer expertise represents one of the most important predictors of performance when interacting with ICT (Information and Communication Technologies) and acquiring computer skills. Due to demographic changes, the older adult will become increasingly important as a potential user. However, there is a lack of instruments for the assessment of computer expertise in older adults, especially for novice users with restricted prior computer knowledge. A computer expertise (CE) questionnaire for older adults was developed, analysed (Study I) and validated (Study II). Item-analysis showed that the CE-questionnaire is particularly appropriate for the computer knowledge level of older adults and measures computer expertise sufficiently. Furthermore, it was found that computer experience (in terms of frequency of computer usage) is a poor predictor of actual computer performance, which has important implications for the theoretical conceptualization of computer expertise and its assessment.

Prior computer expertise represents one of the most important predictors of performance when interacting with ICT (Information and Communication Technologies) and acquiring computer skills. Due to demographic changes, the older adult will become increasingly important as a potential user. However, there is a lack of instruments for the assessment of computer expertise in older adults, especially for novice users with restricted prior computer knowledge. A computer expertise (CE) questionnaire for older adults was developed, analysed (Study I) and validated (Study II). Item-analysis showed that the CE-questionnaire is particularly appropriate for the computer knowledge level of older adults and measures computer expertise sufficiently. Furthermore, it was found that computer experience (in terms of frequency of computer usage) is a poor predictor of actual computer performance, which has important implications for the theoretical conceptualization of computer expertise and its assessment.

Icons are often considered as language free and therefore assumed to be especially suited for inter-cultural usage. This article examines if icons within the mobile context are inter-culturally comprehensible. The study was carried out in Kerala, South India. Fifty-eight participants of a wide age range (17–75 years) volunteered to take part. The icons under study were representatives for common mobile phone functions and were partly taken from real interfaces and were partly self-created. Icons varied in their concreteness/abstractness and their visual complexity. A naming method was adopted: Participants had first to evaluate what a specific icon pictured (pictorial transparency) and, directly after, they had to indicate the icon's meaning in the context of mobile communication (semantic transparency and comprehensibility). Results showed that the comprehensibility of icons mainly depend on two major characteristics, which can be regarded as culture-unspecific. No matter which cultural background users have, the more details an icon contains and the more concrete an icon is, the more it is correctly interpreted. However, we identified also cultural influences on the comprehensibility of specific icons, showing that icon design also should consider cultural specificities.

In this paper we describe an experiment, in which we examined older and younger adults when interacting with a simulated PDA (personal digital assistant). Independent variables were users' age (young vs. older) and device interface (hyperlink vs. no hyperlink). Dependent variables were the effectiveness and efficiency of menu navigation. To understand how user characteristics influence performance, spatial ability, verbal memory, computer expertise and technical self-confidence were determined. Technology experienced young and older adults (benchmark testing) took part. They had to solve four tasks either with hyperlink interface or without hyperlinks in the interface. The method to collect, to automatically analyze and to structure the data according to interaction sequences and presumed user intentions is a novel approach supported by the open source software tool Clever [12]. The tool is briefly described; more details can be found in [23]. Results revealed that hyperlink interfaces showed overall higher effectiveness. However, the impact of hyperlinks for efficiency was age-related. Younger adults strongly benefit from having hyperlinks. The contrary was the case for older adults, who showed higher menu disorientation when using hyperlinks.

The present study investigates the impact of different key solutions of mobile phones on users' effectiveness and efficiency using the devices. In the first experiment, 36 children (9 – 14 years) and in the second experiment 45 young adults (19 – 33 years) completed four common phone tasks twice consecutively on three simulated phones that had identical menus, but different key solutions. An approach was undertaken to quantify the complexity of keys in three models, incorporating different factors contributing to the keys' complexity (number of key options, number of modes and number of modes with a semantically dissimilar meaning), in order to predict users' performance decrements. As a further main factor, the degree of the users' locus of control (LOC) was measured and interactions with performance outcomes were studied. As dependent measures, the number of inefficient keystrokes, the number of tasks solved and the processing time were determined. Results showed a significant effect of control key solutions on users' efficiency and effectiveness for both children and young adults. Moreover, children's LOC values significantly interacted with performance: children with low LOC values showed the lowest performance and no learnability, especially when using keys with a high complexity. From the three factors contributing to the complexity of keys, keys exerting different functions with semantically inconsistent meanings had the worst effect on performance. It is concluded that in mobile user interface design keys with semantically inconsistent meanings should be generally avoided.

The current study was concerned with the basic question of how to overcome users' disorientation when navigating through hierarchical menus in small-screen technical devices, as for example mobile phones. In these devices, menu functions are typically organized in a tree structure. Two different navigation aids were implemented into a computer simulation of a real mobile phone (Siemens S45®). The interface of the first navigation aid (the "category" aid) showed the name of the current category as well as a list of its contents. The interface of the other navigation aid (the "tree" aid) was identical to the first except that it also showed the parents and parent–parents of the current of the category and it indented the subcategories to emphasize the hierarchical structure. For the study, 16 younger (23–28 years) and 16 older adults (46–60 years) had to solve 9 common phone tasks twice consecutively to measure learnability. To gain further insight into user characteristics modulating navigation performance and possibly interacting with the utility of the navigation aids, we assessed users' verbal memory and spatial abilities. Dependent variables were task effectiveness (number of tasks solved) and efficiency (time on task, number of returns in menu hierarchy, and returns to the top). The results reveal a consistent and significant advantage of the tree aid for both age groups, an advantage that was larger for users with lower spatial abilities and older adults. In general, older adults had lower verbal memory and spatial abilities, which were found to account for their lower navigation performance. We assume that the strong advantage of the tree aid is due to the spatial information on the menu structure, which thus conveys survey knowledge. This allows users to form an adequate mental representation of the menu. It is recommended to add a navigation aid providing survey knowledge into the displays of small-screen devices to achieve better overall performance.

In this experiment, older and younger novice mobile phone users were examined when using handsets of different complexity. The independent variables were user age (young: 20 – 35 years; old: 50 – 64 years) and cognitive complexity of two mobile phones (Nokia 3210; Siemens C35i). The cognitive complexity of the phones was defined by the number of production rules applied when processing the four experimental tasks. Dependent variables were effectiveness and efficiency as taken from user protocols and the reported ease of use. The less complex phone (Nokia) performed significantly better than the complex one (Siemens). However, the benefit from the lower complexity was much larger than theoretically predicted. Thus, defining cognitive complexity of technical devices by the number of production rules does not account for the real difficulties which users experience. Older users had a lower navigation performance than younger users, however their performance matched younger users' when using mobiles with low complexity.

The study focuses on usability, ease of use and learnability of three different mobile phones (Nokia 3210, Siemens C35i, Motorola P7389). The first independent variable refers to the complexity of the menu (depth/breadth of the menu tree) and navigation keys (number/functionality). The Nokia phone had the lowest and the Motorola the highest complexity, with the Siemens phone ranging between them. The second independent variable was user expertise: 30 novices and 30 experts solved six telephone tasks. In order to assess effects of learnability, tasks were presented twice. Differences between the mobile phones regarding effectiveness, efficiency and learnability were found: The best performance was shown by Nokia users. The remaining two phones did not differ significantly, although the most complex phone was superior to the phone of medium complexity which had the lowest performance. Moreover, an effect of expertise was confirmed, though suboptimal interfaces were identified as lessening the advantage of expertise. Specific weaknesses of the tested phones are discussed.