Papers by Granit Luzhnica
Proceedings of the 2016 ACM International Symposium on Wearable Computers - ISWC '16, 2016
ACM CHI Conference on Human Factors in Computing Systems Proceedings (CHI 2019), 2019
This paper proposes methods of optimising alphabet encoding for skin reading in order to avoid pe... more This paper proposes methods of optimising alphabet encoding for skin reading in order to avoid perception errors. First, a user study with 16 participants using two body locations serves to identify issues in recognition of both individual letters and words. To avoid such issues, a two-step optimisation method of the symbol encoding is proposed and validated in a second user study with eight participants using the opti-mised encoding with a seven vibromotor wearable layout on the back of the hand. The results show signiicant improvements in the recognition accuracy of letters (97%) and words (97%) when compared to the non-optimised encoding.
Proceedings of the 2018 International Symposium on Wearable Computers (ISWC 2018), 2018
This paper investigates the effects of using passive haptic learning to train the skill of compre... more This paper investigates the effects of using passive haptic learning to train the skill of comprehending text from vibrotactile patterns. The method of transmitting messages, skin-reading, is effective at conveying rich information but its active training method requires full user attention, is demanding, time-consuming, and tedious. Passive haptic learning offers the possibility to learn in the background while performing another primary task. We present a study investigating the use of passive haptic learning to train for skin-reading.
Vibrotactile skin-reading uses wearable vibrotactile displays to convey dynamically generated tex... more Vibrotactile skin-reading uses wearable vibrotactile displays to convey dynamically generated textual information. Such wearable displays have potential to be used in a broad range of applications. Nevertheless, the reading process is passive, and users have no control over the reading flow. To compensate for such drawback, this paper investigates what kind of interactions are necessary for vibrotactile skin reading and the modalities of such interactions. An interaction concept for skin reading was designed by taking into account the reading as a process. We performed a formative study with 22 participants to assess reading behaviour in word and sentence reading using a six-channel wearable vibrotactile display. Our study shows that word based interactions in sentence reading are more often used and preferred by users compared to character-based interactions and that users prefer gesture-based interaction for skin reading. Finally, we discuss how such wearable vibrotactile displays could be extended with sensors that would enable recognition of such gesture-based interaction. This paper contributes a set of guidelines for the design of wearable haptic displays for text communication.
This paper investigates sensitivity based prioritisation in the construction of tactile patterns.... more This paper investigates sensitivity based prioritisation in the construction of tactile patterns. Our evidence is obtained by three studies using a wearable haptic display with vibrotactile motors (tactors). Haptic displays intended to transmit symbols often suffer the tradeoff between throughput and accuracy. For a symbol encoded with more than one tactor simultaneous onsets (spatial encoding) yields the highest throughput at the expense of the accuracy. Sequential onset increases accuracy at the expense of throughput. In the desire to overcome these issues, we investigate aspects of prioritisation based on sensitivity applied to the encoding of haptics patterns. First, we investigate an encoding method using mixed intensities, where different body locations are simultaneously stimulated with different vibration intensities. We investigate whether priori-tising the intensity based on sensitivity improves identification accuracy when compared to simple spatial encoding. Second, we investigate whether prioritising onset based on sensitivity affects the identification of overlapped spatiotemporal patterns. A user study shows that this method significantly increases the accuracy. Furthermore, in a third study, we identify three locations on the hand that lead to an accurate recall. Thereby, we design the layout of a haptic display equipped with eight tactors, capable of encoding 36 symbols with only one or two locations per symbol.
This paper investigates the communication of natural language messages using a wearable haptic di... more This paper investigates the communication of natural language messages using a wearable haptic display. Our research spans both the design of the haptic display, as well as the methods for communication that use it. First, three wearable configurations are proposed basing on haptic perception fundamentals. To encode symbols, we devise an overlapping spatiotemporal stimulation (OST) method, that distributes stimuli spatially and temporally with a minima gap. An empirical study shows that, compared with spatial stimulation , OST is preferred in terms of recall. Second, we propose an encoding for the entire English alphabet and a training method for letters, words and phrases. A second study investigates communication accuracy. It puts four participants through five sessions, for an overall training time of approximately 5 hours per participant. Results reveal that after one hour of training, participants were able to discern 16 letters, and identify two-and three-letter words. They could discern the full English alphabet (26 letters, 92% accuracy) after approximately three hours of training, and after five hours participants were able to interpret words transmitted at an average duration of 0.6s per word.
Lecture Notes in Computer Science, 2011
ABSTRACT
ABSTRACT Reflective learning is an important activity of knowledgeworkers in order to improve fut... more ABSTRACT Reflective learning is an important activity of knowledgeworkers in order to improve future working-behaviours. The insights gained by reflective learning are based on re-experiencing and re-evaluating past working situations. One time- and cost-effective way to support reflective learning is the employment of applications that collect data about working processes, store the data in user profiles, and visualise it in order to provide timely feedback to the employees. However, a single application can only capture part of the data that might be relevant for reflection and the parallel use of several applications leads to high demands on the user regarding the interpretation of relationships between several single visualizations. A combined visualisation of data captured by different apps should enhance the support for reflection about the working behaviour and experiences. This paper introduces an overlapping user profile application, which combines and aggregates data captured by various applications. The goal of this overlapping application is to provide higher-level reflection possibilities by combining visualisations of different application data in order to better induce and support reflective learning at work. A first proof-of-concept of such an approach indicates that a combined user profile application and especially it’s visualisations can be beneficial with regard to reflective learning and can enhance the awareness about the multiple aspects of a user’s work life.
This paper explores the recognition of hand gestures based on a data glove equipped with motion, ... more This paper explores the recognition of hand gestures based on a data glove equipped with motion, bending and pressure sensors. We se- lected 31 natural and interaction-oriented hand gestures that can be adopted for general-purpose control of and communication with computing systems. The data glove is custom-built, and contains 13 bend sensors, 7 motion sensors, 5 pressure sensors and a magne- tometer. We present the data collection experiment, as well as the design, selection and evaluation of a classification algorithm. As we use a sliding window approach to data processing, our algorithm is suitable for stream data processing. Algorithm selection and feature engineering resulted in a combination of linear discriminant anal- ysis and logistic regression with which we achieve an accuracy of over 98.5% on a continuous data stream scenario. When removing the computationally expensive FFT-based features, we still achieve an accuracy of 98.2%.
Conference Presentations by Granit Luzhnica
Haptic displays are commonly limited to transmitting a discrete set of tactile motives. In this p... more Haptic displays are commonly limited to transmitting a discrete set of tactile motives. In this paper, we explore the transmission of real-valued information through vibrotactile displays. We simulate spatial continuity with three perceptual models commonly used to create phantom sensations: the linear , logarithmic and power model. We show that these generic models lead to limited decoding precision, and propose a method for model personalization adjusting to idiosyncratic and spatial variations in perceptual sensitivity. We evaluate this approach using two haptic display layouts: circular, worn around the wrist and the upper arm, and straight, worn along the forearm. Results of a user study measuring continuous value decoding precision show that users were able to decode continuous values with relatively high accuracy (4.4% mean error), circular layouts performed particularly well, and per-sonalisation through sensitivity adjustment increased decoding precision.
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Papers by Granit Luzhnica
Conference Presentations by Granit Luzhnica