Papers by Christos Katsanos
Teleoperation of an agricultural robotic system requires effective and efficient human-robot inte... more Teleoperation of an agricultural robotic system requires effective and efficient human-robot interaction. This paper investigates the usability of different interaction modes for agricultural robot teleoperation. Specifically, we examined the overall influence of two types of output devices (PC screen, head mounted display), two types of peripheral vision support mechanisms (single view, multiple views), and two types of control input devices (PC keyboard, PS3 gamepad) on observed and perceived usability of a teleoperated agricultural sprayer. A modular user interface for teleoperating an agricultural robot sprayer was constructed and field-tested. Evaluation included eight interaction modes: the different combinations of the 3 factors. Thirty representative participants used each interaction mode to navigate the robot along a vineyard and spray grape clusters based on a 2 × 2 × 2 repeated measures experimental design. Objective metrics of the effectiveness and efficiency of the human-robot collaboration were collected. Participants also completed questionnaires related to their user experience with the system in each interaction mode. Results show that the most important factor for human-robot interface usability is the number and placement of views. The type of robot control input device was also a significant factor in certain dependents, whereas the effect of the screen output type was only significant on the participants’ perceived workload index. Specific recommendations for mobile field robot teleoperation to improve HRI awareness for the agricultural spraying task are presented.
Proceedings of the 19th Panhellenic Conference on Informatics - PCI '15, 2015
A considerable interest in using web 2.0 technologies, such as wikis, in education is observed re... more A considerable interest in using web 2.0 technologies, such as wikis, in education is observed recently.
Despite the advantages of the wiki technology, a number of questions concerning design of appropriate
activities and their learning effectiveness remain open. In this paper, we present the results of three activities
involving first-year University students using wikis to learn basic concepts related to information technology.
Three activities of different classes were designed and delivered to the students using the framework
proposed by West and West (2009). In all studies, one-group pretest–posttest design was adopted and results
illustrated significant improvement in learning outcomes, in particular for students with low initial
performance. The average students’ questionnaire score jumped from 39.0/100 to 57.3/100. No significant
effect of both students’ role in the activity and their school stream on learning gain was observed. Finally,
regardless of the activity’s class and learning goal a persistent pattern of high learning gain was observed.
Perceived usability affects greatly student's learning effectiveness and overall learning experie... more Perceived usability affects greatly student's learning effectiveness and overall learning experience, and thus is an important requirement of educational software. The System Usability Scale (SUS) is a well-researched and widely used questionnaire for perceived usability evaluation. However, surprisingly few studies have used SUS to evaluate the perceived usability of learning management systems (LMSs). This paper presents an empirical evaluation of the SUS questionnaire in the context of LMSs' perceived usability evaluation. Eleven studies involving 769 students were conducted, in which participants evaluated the usability of two LMSs (eClass and Moodle) used within courses of their curriculum. It was found that the perceived usability of the evaluated LMSs is at a satisfactory level (mean SUS score 76.27). Analysis of the results also demonstrated the validity and reliability of SUS for LMSs' evaluation, and that it remains robust even for small sample sizes. Moreover, the following SUS attributes were investigated in the context of LMSs evaluation: gender, age, prior experience with the LMS, Internet self-efficacy, attitude towards the Internet and usage frequency of the LMS.
This paper investigates gender differences in stress recognition in human computer interaction (H... more This paper investigates gender differences in stress recognition in human computer interaction (HCI) for both objective (i.e., skin conductance) and subjective (i.e., valence-arousal VA ratings) metrics. To this end, 31 healthy participants, 18 females, performed five HCI tasks, while their skin conductance was recorded. These selected HCI tasks were the ones listed as the most stressful, by a group of typical computer users, who were involved in a face to face pre-experiment interview for the identification of stressful cases in computer interaction. After each task, participants rated their interaction experience using the valence-arousal scale. The collected data were split based on participants' gender. Skin conductance signals were analyzed using seven popular machine learning classifiers. In both groups the best stress recognition accuracy for all tasks was achieved by Linear Discriminant Analysis LDA; Males: Mean=94.8% and SD=1.5%, Females: Mean=98.9% and SD=0.3%. Self-reported data analysis revealed a significant difference on how both genders communicate their emotions using the arousal scale. Our findings tend to suggest that gender does not affect skin conductance data during subtle HCI tasks. However subjective ratings such as arousal of emotional experience must be utilized carefully.
Proceedings of the 11th Biannual Conference on Italian SIGCHI Chapter - CHItaly 2015, 2015
Thirty-one healthy participants performed five stressful HCI tasks (stimuli) while their skin con... more Thirty-one healthy participants performed five stressful HCI tasks (stimuli) while their skin conductance signals were monitored. The selected interaction tasks were most frequently listed as stressful by 15 interviewees, who were typical computer users. At the end of each task, participants expressed their perceived emotional experience using the dimensional Valence-Arousal (VA) rating space. The obtained VA ratings were used to define nine rectangular regions in the VA space, labeled as "stress". Next, five popular machine learning classifiers were employed to identify stress based on the associated skin conductance signals per tested region. Results showed sufficient cross-region stress recognition accuracy; L-SVM: Mean=62.3%, SD=9.3%. Our findings support that the VA scale may be used for stress self-assessments in the context of subtle interaction events, which are typically expected in most HCI tasks.
Lecture Notes in Computer Science, 2015
This paper reports an experiment for stress recognition in humancomputer interaction. Thirty-one ... more This paper reports an experiment for stress recognition in humancomputer interaction. Thirty-one healthy participants performed five stressful HCI tasks and their skin conductance signals were monitored. The selected tasks were most frequently listed as stressful by 15 typical computer users who were involved in pre-experiment interviews asking them to identify stressful cases of computer interaction. The collected skin conductance signals were analyzed using seven popular machine learning classifiers. The best stress recognition accuracy was achieved by the cubic support vector machine classifier both per task (on average 90.8%) and for all tasks (Mean=98.8%, SD=0.6%). This very high accuracy demonstrates the potentials of using physiological signals for stress recognition in the context of typical HCI tasks. In addition, the results allow us to move on a first integration of the specific stress recognition mechanism in PhysiOBS, a previously-proposed software tool that supports researchers and practitioners in user emotional experience evaluation.
The InfoScent Evaluator (ISEtool) is a semi-automated tool developed by the HCI Group of the Univ... more The InfoScent Evaluator (ISEtool) is a semi-automated tool developed by the HCI Group of the University of Patras. The aim of the tool is to facilitate the identification of navigability and findability impasses in the user's interaction with a Web site. ISETool evaluates the semantic appropriateness of the hyperlinksʼ descriptions presented in a Web site based upon Information Foraging Theory, and using semantic similarity measures (e.g. Latent Semantic Analysis - LSA) to exploit computationally the theoretical model. The basic underlying assumption in ISEtool is that users have some information goal and their surfing patterns through the site are guided by information 'scent'. Information scent is defined as the imperfect perception of the value, cost, or access path of information sources obtained from proximal cues (i.e. snippets of information), such as WWW links (Card et al 2001, Pirolli 2007). Semantic similarity measures are used to quantify this concept of infor...
Usability of interactive web forms is a critical aspect of the overall user experience. The video... more Usability of interactive web forms is a critical aspect of the overall user experience. The video presents a short demo of KLM Form Analyzer (KLM-FA), a tool to automatically evaluate web form filling tasks is presented. The tool carries out Keystroke Level Model symbolic calculations of the time required to fill a specific web form in a straightforward and automatic manner. Moreover, it calculates the form completion time according to different interaction strategies or users' characteristics. In addition, Fitts' law is computationally realized to calculate the exact time required to move the cursor to the form elements. Preliminary case studies illustrated the tool capability to support both designers and evaluators in an efficient and effective manner. To download and try the tool or learn more you can visit http://klmformanalyzer.weebly.com
The Automated Card Sorting tool (AutoCardSorter) is an automated tool that supports the design an... more The Automated Card Sorting tool (AutoCardSorter) is an automated tool that supports the design and evaluation of the information architecture of information-rich applications, like most Web sites. AutoCardSorter is inspired by the Card Sorting user method and employs semantic similarity measures (e.g. Latent Semantic Analysis - LSA)) to calculate the semantic similarity of different Web pages and clustering algorithms (e.g. Hierarchical Clustering Algorithms) to cluster accordingly the information space. The tool also implements statistically-based heuristics (e.g. Elbow Criterion) to support the user in determining the number of categories. AutoCardSorter is aimed at providing the necessary flexibility and efficiency to the practitioners to design or evaluate the information architecture of a web site. Such an automated approach could substantially accelerate the design and evaluation lifecycle, by providing valuable insight and increasing the possibility to explore alternative des...
Proceeding of the twenty-sixth annual CHI conference on Human factors in computing systems - CHI '08, 2008
In this paper, we describe an innovative tool that supports the design and evaluation of the info... more In this paper, we describe an innovative tool that supports the design and evaluation of the information architecture of a Web site. The tool uses Latent Semantic Analysis and hierarchical clustering algorithms to provide optimal information navigation schemes in an automated manner. The proposed, tool-based, approach addresses the problem of reasonable content structuring, which established techniques such as card sorting also address. A real world case study depicted substantial effectiveness gain, without expense in the quality of results. We argue that such an approach could facilitate information-rich applications design, like most Web sites, by reducing time and resources required.
In this paper, the effectiveness of a framed wiki-based learning activity is investigated. A one-... more In this paper, the effectiveness of a framed wiki-based learning activity is investigated. A one-group pretest-posttest design was adopted to examine the impact of the activity. The study involved 139 first year university students of a Greek Education Department using wikis to learn general information about Web 2.0 and its applications, in the context of an introductory ICT course. Study results showed significant improvement in learning outcomes, both for students with low and high initial performance. In addition, it was found that students benefited from the activity regardless of their role in the project. Furthermore, results showed that students with a higher number of logged wiki edits had a significantly higher learning gain compared to those that were less active. These findings suggest that properly designed, framed wiki-based activities have great potential in higher education.
As computing is changing parameters, apart from effectiveness and efficiency in human-computer in... more As computing is changing parameters, apart from effectiveness and efficiency in human-computer interaction, such as emotion have become more relevant than before. In this paper, a new tool-based evaluation approach of user's emotional experience during human-computer interaction is presented. The proposed approach combines user's physiological signals, observation data and self-reported data in an innovative tool (PhysiOBS) that allows continuous and multiple emotional states analysis. To the best of our knowledge, such an approach that effectively combines all these user-generated data in the context of user's emotional experience evaluation does not exist. Results from a preliminary evaluation study of the tool were rather encouraging revealing that the proposed approach can provide valuable insights to user experience practitioners.
Introducing semi-automatic teleoperation of an agricultural robotic system can enable improved pe... more Introducing semi-automatic teleoperation of an agricultural robotic system can enable improved performance, overcoming the complexity that current autonomous robots face due to the dynamic and unstructured agriculture environment. A teleoperated robot can both leverage the farmers' knowledge and experience while keeping them safe and also help the robot manage the unpredictability of the environment in the field. In this paper we describe the construction of such a teleoperated agricultural robot sprayer that is controlled through a Reality-Based Interaction interface. Two different user interfaces for teleoperating a vineyard spraying robot were experimentally evaluated. In the first condition, participants were provided with a single view (one camera) for teleoperating the robot, whereas in the second condition they had additional views (multiple cameras) supporting peripheral vision and targeted spraying. Analysis of the collected data showed that users in the additional views condition sprayed significantly more grapes and teleoperated the robot with significantly less collisions with obstacles, compared to users who did not have these aids, but also required significantly more time. Participants' perceived usability assessments were not affected by the availability of these additional views.
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Papers by Christos Katsanos
Despite the advantages of the wiki technology, a number of questions concerning design of appropriate
activities and their learning effectiveness remain open. In this paper, we present the results of three activities
involving first-year University students using wikis to learn basic concepts related to information technology.
Three activities of different classes were designed and delivered to the students using the framework
proposed by West and West (2009). In all studies, one-group pretest–posttest design was adopted and results
illustrated significant improvement in learning outcomes, in particular for students with low initial
performance. The average students’ questionnaire score jumped from 39.0/100 to 57.3/100. No significant
effect of both students’ role in the activity and their school stream on learning gain was observed. Finally,
regardless of the activity’s class and learning goal a persistent pattern of high learning gain was observed.
Despite the advantages of the wiki technology, a number of questions concerning design of appropriate
activities and their learning effectiveness remain open. In this paper, we present the results of three activities
involving first-year University students using wikis to learn basic concepts related to information technology.
Three activities of different classes were designed and delivered to the students using the framework
proposed by West and West (2009). In all studies, one-group pretest–posttest design was adopted and results
illustrated significant improvement in learning outcomes, in particular for students with low initial
performance. The average students’ questionnaire score jumped from 39.0/100 to 57.3/100. No significant
effect of both students’ role in the activity and their school stream on learning gain was observed. Finally,
regardless of the activity’s class and learning goal a persistent pattern of high learning gain was observed.