The impact of size and position of reference electrode on the localization of biphasic electrotactile stimulation on the fingertips

Development of haptic interfaces to enrich augmented and virtual reality with the sense of touch is the next frontier for technological advancement of these systems. Among available technologies, electrotactile stimulation enables design of high-density interfaces that can provide natural-like sensation of touch in interaction with virtual objects. The present study investigates the human perception of electrotactile sensations on fingertips, focusing on the sensation localization in function of the size and position of reference electrode. Ten healthy subjects participated in the study, with the task to mark the sensations elicited by stimulating the index fingertip using an 8-pad electrode. The test systematically explored several configurations of the active (position) and reference (position and size) electrode pads. The results indicated that there was a spreading of perceived sensations across the fingertip, but that they were mostly localized below the active pad. The position and size of the reference electrode were shown to affect the location of the perceived sensations, which can potentially be exploited as an additional parameter to modulate the feedback. The present study demonstrates that the fingertip is a promising target for the delivery of high-resolution feedback.The work in this study was performed within the TACTILITY project, which has received funding by European Union’s Horizon 2020 framework programme for research and innovation H2020-ICT-2018-2020/H2020-ICT 2018-3 under grant agreement no. 85671

Remote Health-Monitoring of First Responders over TETRA Links

In this paper, we present a system for remote health-monitoring of first responders over TETRA radio links. The system features a smart garment that periodically records and sends physiological parameters of first responders to a remote agent, which processes the recordings and feeds back the health-status notifications and warnings in the form of electrotactile stimuli. The choice of TETRA as the connectivity solution is driven by its routine use by first responders all over the world, thus representing a convenient and economically-effective connectivity basis. Although the support for data communications in TETRA is rather limited and in practice reduced to the Short Data Service, we show that TETRA can serve the intended purpose in the considered scenario, achieving tolerable delay and message-loss performance. Moreover, when the system is examined and optimized in terms of the peak Age-of-Information, a metric suitable to characterize the quasi-periodic nature of the monitoring process, its performance becomes rather favorable, enabling timely monitoring of the first responders' health status

Encoding of spatial patterns using electrotactile stimulation via a multi-pad electrode placed on the torso

Publisher Copyright: © 2022 The Authors. Artificial Organs published by International Center for Artificial Organ and Transplantation (ICAOT) and Wiley Periodicals LLC.Background: Tactile stimulation can be used to convey information to a user in different scenarios while avoiding overloading other senses. Tactile messages can be transmitted as spatial patterns, potentially allowing for a high information throughput. The aim of the present study was to design and test different encoding schemes to determine the best approach for conveying spatial patterns. Methods: Encoding schemes with simultaneous (SIM) and sequential pad activation (SEQ) were evaluated, including four SEQ variants designed to potentially facilitate the recognition. In SEQ-col and SEQ-row, the column and row of the activated pad were signified using different frequencies, while SEQ-all and SEQ-all-fast included the activation of all pads where those belonging to the pattern were indicated by changes in frequency (ON pads). The success rate (SR) of the pattern identification and the response time were quantified in 15 participants who recognized 20 patterns delivered through a 3 × 2 pad matrix placed on the lateral torso. Results: SIM was not a feasible method to present the patterns (median, 15%; IQR, 5%). The SR improved with SEQ (median, 60%; IQR, 20%) and further increased with additional cues, particularly with SEQ-row (median, 78.3%; IQR, 23.3%) and SEQ-all (median, 96.7%; IQR, 5%). Importantly, the stimulation time of SEQ-all could be decreased without a substantial drop in accuracy (SEQ-all-fast: median, 89.2%; IQR, 19.2%). Conclusions: The spatiotemporal stimulation with sequential activation of all pads (SEQ-all) seems to be the method of choice when conveying tactile messages as spatial patterns. This is an important outcome for increasing the information bandwidth of communication through the tactile channel.The present study was supported by the project SIXTHSENSE funded by the European Union's Horizon 2020 research and innovation program under grant agreement No. 883315.Peer reviewe

PARAMETARSKO GENERISANJE I PRORAČUN EFIKASNOSTI SOLARNIH PRIJEMNIKA UPOTREBOM NAPREDNIH CAD ALATA

In this paper, the implementation of the solar collectors efficiency calculation in the automatic generation of so-lar collectors was carried out using advanced CAD tools. The mathematical model, developed by the authors in previ-ous research, was used. Within this research an algorithm for generating and calculating solar collectors has been developed that is suitable for the geometrical characteristics of the: absorber with circular cross-sectional pipes, ab-sorber with rectangular cross-sectional pipes and absorbers with square cross-section pipes. The results of this re-search show the importance of using advanced CAD tools in the design of solar collectors. The use of these solutions leads to a significant reduction in the design of solar collectors. The application of this approach is very easy for prac-tical purposes.Publishe

DETERMINING GEOMETRICAL PARAMETERS OF EXTERNAL WALLS ON LOW-RISE RESIDENTIAL BUILDINGS WITH GABLE AND PITCHED ROOFS AND OPTIMIZATION OF ITS ECOLOGICAL PARAMETERS

This paper analyzes the influence of the implementation of an optimization process in the process of designing residential buildings in order to improve their performance. Optimization parameters which are interesting for this research are building orientation, window area, gable and pitched roofs and overhang. Based on acquired results, this paper gives conclusions on CO2 emissions and discomfort of lowrise residential buildings.Publishe

A NEW MODIFICATION OF GENETIC ALGORITHM FOR SOLVING ENGINEERING OPTIMIZATION PROBLEMS

Today, for solving complex engineering problems it is necessary to use optimization methods. Popular methods for finding optimal characteristics are heuristic methods, and the most predominant in use is the genetic algorithm. This paper presents a new modification of the genetic algorithm (iGA) and its testing on complex engineering problems. Results are compared to relevant results from literature for genetic algorithm and other modern optimization methods. The developed modification represents a contribution for practical optimization of engineering problems.Publishe

DETERMINATION OF GEOMETRIC PARAMETERS FOR THE OPTIMAL UTILIZATION OF SOLAR COLLECTORS

U ovom radu izvršeno je određivanje geometrijskih parametara prijemnika sunčeve energije optimizacionim metodama. Razvijen je matematički model za određivanje povoljnih geometrijskih karakteristika prijemnika sunčeve energije u cilju maksimizacije njihovog iskorišćenja. Optimalno rešenje kreirano je za geometrijske karakteristike prijemnika sunčeve energije sa cevima kružnog poprečnog preseka i prijemnika sunčeve energije sa cevima pravougaonog poprečnog preseka. Izvršena je uporedna analiza iskorišćenja oba tipa prijemnika sunčeve energije. Rezultatima ovog istraživanja predstavljen je značaj primene optimizacije i parametarskog modeliranja u projektovanju prijemnika sunčeve energije. Ova rešenja mogu se jednostavno primeniti u praksi. Na kraju rada su razmotreni rezultati i smernice za dalja istraživanja.Publishe

COMPARATIVE ANALYSIS OF ANALYTICAL CALCULATION AND OPTIMIZATION ON GEARBOX DIMENSIONS AND VOLUME

For the purposes of this research analytical and numerical calculations of gearboxes have been done. In the process of numerical calculation optimization was implemented. Optimization was done according to four different criteria: length, width, height and volume, whose values are compared to the analytical calculations according to the aforementioned criteria individually. This approach shows better gearbox performance which vary from 3% to 47% depending on the analytical calculation. The analytical calculations were conducted using suggestions from ISO standards, Petrisevic, GOST standards, and Kudrijavcev. For optimization, the Complex Box method has been used and an original software has been developed for these purposes. All real constraints have been taken into account in order to have the optimal results be usable in real applications.Publishe

Anatomic and MRI bases for medullary infarctions with patients' presentation

Objective: There is a low incidence of the medullary infarctions and sparse data about the vascular territories, as well as a correlation among the anatomic, magnetic resonance imaging (MRI) and neurologic signs. Materials and methods: Arteries of the 10 right and left sides of the brain stem were injected with India ink, fixed in formalin and microdissected. The enrolled 34 patients with medullary infarctions underwent a neurologic, MRI and Doppler examination. Results: Four types of the infarctions were distinguished according to the involved vascular territories. The isolated medial medullary infarctions (MMIs) were present in 14.7%. The complete MMIs comprised one bilateral infarction (2.9%), whilst the incomplete and partial MMIs were observed in 5.9% and 8.9%, respectively. The anterolateral infarctions (ALMIs) were very rare (2.9%). The complete and incomplete lateral infarctions (LMIs), noted in 35.3%, comprised 11.8% and 23.6%, respectively, that is, the anterior (5.9%), posterior (8.9%), deep (2.9%), and peripheral (5.9%). Dorsal ischemic lesions (DMIs) occurred in 11.8%, either as a complete (2.9%), or isolated lateral (5.9%) or medial infarctions (2.9%). The remaining ischemic regions belonged to various combined infarctions of the MMI, ALMI, LMI and DMI (35.3%). The infarctions most often affected the upper medulla (47.1%), middle (11.8%), or both (29.5%). Several motor and sensory signs were manifested following infarctions, including vestibular, cerebellar, ocular, sympathetic, respiratory and auditory symptoms. Conclusions: There was a good correlation among the vascular territories, MRI ischemia features, and neurologic findings regarding the medullary infarctions.Peer reviewe