Krešimir Ćosić

Physiology-driven adaptive virtual reality stimulation for prevention and treatment of stress related disorders

The significant proportion of severe psychological problems related to intensive stress in recent large peacekeeping operations underscores the importance of effective methods for strengthening the prevention and treatment of stress-related disorders. Adaptive control of virtual reality (VR) stimulation presented in this work, based on estimation of the persons emotional state from physiological signals, may enhance existing stress inoculation training (SIT). Physiology-driven adaptive VR stimulation can tailor the progress of stressful stimuli delivery to the physiological characteristics of each individual, which is indicated for improvement in stress resistance. Following an overview of physiology-driven adaptive VR stimulation, its major functional subsystems are described in more detail. A specific algorithm of stimuli delivery applicable to SIT is outlined.

Real-Time Emotional State Estimator for Adaptive Virtual Reality Stimulation

The paper presents design and evaluation of emotional state estimator based on artificial neural networks for physiology-driven adaptive virtual reality (VR) stimulation. Real-time emotional state estimation from physiological signals enables adapting the stimulations to the emotional response of each individual. Estimation is first evaluated on artificial subjects, which are convenient during software development and testing of physiology-driven adaptive VR stimulation. Artificial subjects are implemented in the form of parameterized skin conductance and heart rate generators that respond to emotional inputs. Emotional inputs are a temporal sequence of valence/arousal annotations, which quantitatively express emotion along unpleasant-pleasant and calm-aroused axes. Preliminary evaluation of emotional state estimation is also performed with a limited set of humans. Human physiological signals are acquired during simultaneous presentation of static pictures and sounds from valence/arousalannotated International Affective Picture System and International Affective Digitized Sounds databases.

Design and implementation of a hardware-in-the- loop simulator for a semi-automatic guided missile system

Abstract Hardware in the loop (HIL) simulation based on modern digital signal processors is a cost-effective technology for the design and evaluation of various sophisticated weapon and industrial systems. In this article a HIL simulation is presented through the very complex problem of modernisation of the semi-automatic command to line of sight (SACLOS) missile system. The presented examples illustrate the importance of the HIL simulation technology for the cost-effective, non-destructive prototype development of such SACLOS systems. The key role of a flexible simulation platform consisting of 4 TMS320C40 digital signal processors for efficient real-time simulation of the implemented SACLOS subsystem models is also emphasised in this paper.

STIMONT: a core ontology for multimedia stimuli description

Affective multimedia documents such as images, sounds or videos elicit emotional responses in exposed human subjects. These stimuli are stored in affective multimedia databases and successfully used for a wide variety of research in psychology and neuroscience in areas related to attention and emotion processing. Although important all affective multimedia databases have numerous deficiencies which impair their applicability. These problems, which are brought forward in the paper, result in low recall and precision of multimedia stimuli retrieval which makes creating emotion elicitation procedures difficult and labor-intensive. To address these issues a new core ontology STIMONT is introduced. The STIMONT is written in OWL-DL formalism and extends W3C EmotionML format with an expressive and formal representation of affective concepts, high-level semantics, stimuli document metadata and the elicited physiology. The advantages of ontology in description of affective multimedia stimuli are demonstrated in a document retrieval experiment and compared against contemporary keyword-based querying methods. Also, a software tool Intelligent Stimulus Generator for retrieval of affective multimedia and construction of stimuli sequences is presented.

A methodology for digital real time simulation of dynamic systems using modern DSPs

Abstract The speedup factor in real time simulation of dynamic systems using multiprocessor resources depends on: the architecture of the multiprocessor system, type of interconnection between parallel processors, numerical methods and techniques used for discretization and task assignment and scheduling policy. The minimization of the number of processors needed for real time simulation requires the minimization of processors times for interprocessor communications and efficient scheduling policy. Therefore, this article presents a methodology for the real time simulation of dynamic systems including a new pre-emptive static assignment and scheduling policy. The advantages of applying digital signal processor with parallel architecture, for example TMS320C40, in real time simulation have been described. Some important issues in real time architectures necessary for efficient multiprocessor real time simulations, such as multiple I/O channels, concurrent I/O and CPU processing, direct high speed interprocessor communications, fast context switching, multiple busses, multiple memories, and powerful arithmetic units are inherent to this processor. These features minimize interprocessor communication time and maximize sustained CPU performance.

Workstation for integrated system design and development

Hardware in the loop simulation has been proven as a very cost effective method in design, development, modification and testing of sophisticated industrial control systems. The Workstation for Integrated System Design and Development presented in this article allows: highly efficient real time simulation of dynamic systems using the available multiprocessor resources, micropro cessor control system design and implementa tion using suitable software package for synthesis and code generation, testing and verification of microprocessor based controller using real time interaction with multiproces sor simulator. The hardware configuration of Workstation for ISDD is based on inexpensive general purpose single board computers, which are very attractive and more favorable in speed/cost ratio in relation to the other powerful single processor solution. The appropriate examples show the applicability of these multi-microprocessor resources in: real time simulation of linear time invariant systems, comparative analysis of different discretization techniques and digital control system design and testing.

A system for head-neck rehabilitation exercises based on serious gaming and virtual reality

Acute and chronic neck pain are common medical conditions, and the treatment typically includes physical therapy involving daily exercises. Insufficient motivation of people afflicted with neck pain to adhere to the prescribed exercise regimen may delay their recovery. Accordingly, in this work, we propose a system that motivates the users to perform neck exercises by engaging them in a serious exergame within virtual reality (VR) environment. The system measures the users’ neck movements via a few static and dynamic kinematic tests and a novel VR serious game, tailored to the neck range of motion of each individual user. The game is designed to make the users perform rehabilitative neck movements according to the prescribed exercise regimen while playing. The analysis of acquired data from VR hardware provides insight into flexibility of the neck during head movements and overall neck kinematics, which is valuable for assessment of pain-related stiffness, as well as for progress monitoring. In a user study performed with the proposed system and the Oculus Rift DK2 VR headset, we show that the users find exercising more interesting and engaging when using the proposed system, and that introducing visually rich VR environments makes the users more motivated to continue exercising.

Interactive scenario control in virtual environments

abstract The important needs of training, exposure, and adoption of specific skills and operating procedures in a safe and cost-effective way strongly encourage the use of virtual environments. A critical component in such environments is interactive control of events and objects that are presented to a trainee. In this paper, we present a platform named the Interactive Scene Control Environment that is composed of trainee and trainer supervision parts. The trainer supervision part enables interactive control of placement and behavior of the objects inserted in the trainees’ scene. The overall system architecture for such a platform is developed and a mechanism for scenario definition is proposed.

fMRI neural activation patterns induced by professional military training

Professional military training makes tough demands on soldiers’ perceptual and motor skills, as well as on their physical fitness and cognitive capabilities in the course of preparation for stressful operational environments. In this pilot study we attempted to identify difference in pattern of neural responses between extensively trained, professional mission-ready soldiers and novice soldiers during audiovisual simulation of mission conditions. We performed fMRI scanning on a few volunteers during presentation of semantically relevant video-clips of real combat from Afghanistan to evaluate influence of military training on mental responses of soldiers. We showed that for professional mission-ready soldiers a week before their deployment to Afghanistan, videoclips with deadly ambush combat induce greater overall brain activation compared to novice soldiers. Missionready soldiers showed greater activation in premotor/prefrontal cortex, posterior parietal cortex, and posterior temporal cortex. These results imply that fMRI technique could be used as challenging step forward in the multidimensional evaluation of military training influence on neural responses and operational capabilities of professional soldiers. This is extremely important not only for potential failure prevention and mere success of the mission, but even more for the survival and the well-being of the servicemen and servicewomen.

Emotionally Based Strategic Communications and Societal Stress-Related Disorders

This article discusses the potential of emotionally based strategic communications (EBSCs) as an extension of traditional strategic communications in prevention of societal stress-related disorders. The concept of EBSCs takes into consideration dominant emotional maps of a specific sociocultural environment in which communications take place. EBSCs may have a significant potential to transform mainly negative-dominant emotional maps of targeted social groups into more positive ones, as a precondition of building a more resilient and stress-resistant social environment. A better understanding of dominant emotional maps and their conditioning may facilitate restoration of more positive emotional maps by touching the right emotions of significant parts of the targeted social groups in the right way. Dominant emotional maps of societies afflicted by economic downturns, natural disasters, conflicts etc., are typically characterized by negatively valenced emotions. Persistent negatively valenced group-based dominant emotions may be used as a quantitative statistical measure of potential stress-related disorders and post-traumatic stress disorders among respected group members. The toxic power of extreme negative emotions, attitudes, actions, and behavior might be reduced by EBSCs as a communication method for transforming negative-dominant emotional maps into more positive ones. EBSCs are conceptualized as the positively valenced stimulation of a negatively emotionally affected group by an appropriate communication strategy to minimize dominant-negative emotional maps and behavior of the targeted group.