Biblio

Background: Researchers and practitioners have been using code complexity metrics for decades to predict how developers comprehend a program. While it is plausible and tempting to use code metrics for this purpose, their validity is debated, since they rely on simple code properties and rarely consider particularities of human cognition. Aims: We investigate whether and how code complexity metrics reflect difficulty of program comprehension. Method: We have conducted a functional magnetic resonance imaging (fMRI) study with 19 participants observing program comprehension of short code snippets at varying complexity levels. We dissected four classes of code complexity metrics and their relationship to neuronal, behavioral, and subjective correlates of program comprehension, overall analyzing more than 41 metrics. Results: While our data corroborate that complexity metrics can-to a limited degree-explain programmers' cognition in program comprehension, fMRI allowed us to gain insights into why some code properties are difficult to process. In particular, a code's textual size drives programmers' attention, and vocabulary size burdens programmers' working memory. Conclusion: Our results provide neuro-scientific evidence supporting warnings of prior research questioning the validity of code complexity metrics and pin down factors relevant to program comprehension. Future Work: We outline several follow-up experiments investigating fine-grained effects of code complexity and describe possible refinements to code complexity metrics.

With the advancement of Artificial Intelligence technology to make smart devices, understanding how humans develop trust in virtual agents is emerging as a critical research field. Through our research, we report on a novel methodology to investigate user's trust in auditory assistance in a Virtual Reality (VR) based search task, under both high and low cognitive load and under varying levels of agent accuracy. We collected physiological sensor data such as electroencephalography (EEG), galvanic skin response (GSR), and heart-rate variability (HRV), subjective data through questionnaire such as System Trust Scale (STS), Subjective Mental Effort Questionnaire (SMEQ) and NASA-TLX. We also collected a behavioral measure of trust (congruency of users' head motion in response to valid/ invalid verbal advice from the agent). Our results indicate that our custom VR environment enables researchers to measure and understand human trust in virtual agents using the matrices, and both cognitive load and agent accuracy play an important role in trust formation. We discuss the implications of the research and directions for future work.

What makes a security visualization effective? How do we measure visualization effectiveness in the context of investigating, analyzing, understanding and reporting cyber security incidents? Identifying and understanding cyber-attacks are critical for decision making - not just at the technical level, but also the management and policy-making levels. Our research studied both questions and extends our Security Visualization Effectiveness Measurement (SvEm) framework by providing a full-scale effectiveness approach for both theoretical and user-centric visualization techniques. Our framework facilitates effectiveness through interactive three-dimensional visualization to enhance both single and multi-user collaboration. We investigated effectiveness metrics including (1) visual clarity, (2) visibility, (3) distortion rates and (4) user response (viewing) times. The SvEm framework key components are: (1) mobile display dimension and resolution factor, (2) security incident entities, (3) user cognition activators and alerts, (4) threat scoring system, (5) working memory load and (6) color usage management. To evaluate our full-scale security visualization effectiveness framework, we developed VisualProgger - a real-time security visualization application (web and mobile) visualizing data provenance changes in SvEm use cases. Finally, the SvEm visualizations aims to gain the users' attention span by ensuring a consistency in the viewer's cognitive load, while increasing the viewer's working memory load. In return, users have high potential to gain security insights in security visualization. Our evaluation shows that viewers perform better with prior knowledge (working memory load) of security events and that circular visualization designs attract and maintain the viewer's attention span. These discoveries revealed research directions for future work relating to measurement of security visualization effectiveness.

Techno-stress has been a problem in recent years with a development of information technology. Various studies have been reported about a relationship between key typing and psychosomatic state. Keystroke dynamics are known as dynamics of a key typing motion. The objective of this paper is to clarify the mechanism between keystroke dynamics and physiological responses. Inter-stroke time (IST) that was the interval between each keystroke was measured as keystroke dynamics. The physiological responses were heart rate variability (HRV) and respiration (Resp). The system consisted of IST, HRV, and Resp was applied multidimensional directed coherence in order to reveal a causal correlation. As a result, it was observed that strength of entrainment of physiological responses having fluctuation to IST differed in surround by the noise and a cognitive load. Specifically, the entrainment became weak as a cognitive resource devoted to IST was relatively increased with the keystroke motion had a robust rhythm. On the other hand, the entrainment became stronger as a cognitive resource devoted to IST was relatively decreased since the resource also devoted to the noise or the cognitive load.