Virtual Time Research Articles

Virtual trauma patient simulation design using the McGill Simulation Complexity Score (MSCS): a breakthrough in trauma education.

Virtual patient simulations are interactive, computer-based cases. We designed scenarios based on the McGill Simulation Complexity Score (MSCS), a previously described objective complexity score. We aimed to establish validity of the MSCS and introduce a novel learning tool in trauma education at our institution. After design of an easy and difficult patient scenario, we randomized medical students and residents to each perform 1 of the 2 scenarios. We conducted a 2-way analysis of variance of training level (medical student, resident) and scenario complexity (easy, difficult) to assess their effects on virtual time, the number of steps taken in the scenario, beneficial and harmful actions, and the ratio of beneficial over harmful actions. Virtual patient scenarios were successfully designed using the MSCS. Twenty-four medical students and 12 residents participated in the easy scenario (MSCS = 3), and 27 medical students and 12 residents did the difficult scenario (MSCS = 18). Though beneficial actions were similar between students and residents, sudents performed more harmful actions, particularly when the scenario was difficult. One virtual patient died in the easy scenario and 3 died in the difficult one (all medical students). Performance varied with level of complexity and there was significant interaction between level of training and number of steps, as well as with number of harmful actions. Decreasing performance with increasing level of complexity, as defined by the MSCS, suggests this score can accurately quantify difficulty. We established validity of the MSCS and showed its successful application on virtual patient scenario design.

CLINICAL EVALUATION OF INTRAOCULAR PRESSURE MEASUREMENTS USING DIFFERENT TONOMETERS IN PATIENTS OF VARIOUS REFRACTIVE ERRORS

Background: Intraocular pressure (IOP)is an important rst indicator of probability and suspicion of Glaucoma. The virtual IOP status is grossly inuenced by multiple factors including Refractive errors, corneal biomechanics ,central corneal thickness(CCT) and Scleral rigidity. Aim: To compare relative IOP measurements and its variability in Emmetropes, myopic and hypermetropic patients using Schiotz, Goldmann Applanation(GAT)and I-Care Rebound tonometer to establish an equation between virtual and real time IOP. Materials and Methods: This observational prospective study comprised of 100 subjects above the age of 18 years inclusive37 Emmetropes , 31 Hypermetropes and remaining 32 belonged to myopia . Statistical Analysis : Descriptive statistics were performed using SPSS for Windows version 17.0 to calculate the demographic characteristics of the study cohort. The data were expressed as mean values including the standard deviation (SD) and the 95% condence interval (CI). Mean IOP measurements between Schiotz, I-Care and GAT were compared by One way ANOVA along with Individual pair wise comparison by applying Post Hoc Tukey Test for comparison of IOP measurements using a particular method of Tonometry in individuals of myopia, hypermetropia and emmetropia. Results: The highest mean value of CCT 536.667 mum was in Hypermetropes whereas the lowest CCT value of 507.031mum was in myopic eyes with statistically signicant (P<0.05). The mean value for IOP in Emmetropes was16.665 mm Hg for Schiotz , 15.027 Hg for GAT and 15.081 mm Hg for I –Care .Whereas Hypermetropes revealed mean value of 15.055 mm Hg for Schiotz , 14.323 mm Hg for GAT and 14.065 mm Hg for I –Care . The mean value for IOP in Myopic eyes was 16.875 mm Hg for Schiotz , 14.375 mm Hg for GAT and 14.688 mm Hg for I –Care . Conclusion : The study had revealed higher mean value of IOP in Myopic eyes as compare to Emetropic and Hypermetropic subjects. IOP measurements by the Schiotz tonometer were signicantly higher as compare to GAT and I-Care tonometer. Whereas recordings by GAT and I Care tonometers were almost in agreement .Denitive correlation could not be established between pachymetry readings and adjusted IOP following GAT and I –Care tonometry .

Impact localization and force reconstruction for composite plates based on virtual time reversal processing with time-domain spectral finite element method

Composite structures are widely used in different industries as important load-carrying components due to their excellent performance. These structures are prone to be damaged under low-velocity impacts with invisible cracks. Hence, impact identification is a critical part of composite structural health monitoring. In this paper, an approach is developed, which is based on time-reversal (T-R) processing and time-domain spectral finite element method. The spatial and temporal focusing properties of T-R are utilized to locate the impact source and restore the impact force, respectively. Moreover, the impact energy is evaluated by establishing the function of impact force and kinetic energy at the impact moment. The proposed method is validated experimentally for different scenarios. The influences of the signal length and accuracy of the numerical model on the proposed method are discussed in detail. The results demonstrate that the proposed method can correctly locate the impact source in composite structures, and the identified impact force can reproduce the impact event efficiently. The impact localization is essentially independent of the effect of signal length while it is vulnerable to the mesh grid. Besides, the developed method has consistent results in the case of data perturbation of material properties in the numerical model, which shows its good robustness.

Nowcasting Daily Population Displacement in Ukraine through Social Media Advertising Data

AbstractIn times of crisis, real‐time data mapping population displacements are invaluable for targeted humanitarian response. The Russian invasion of Ukraine on February 24, 2022, forcibly displaced millions of people from their homes including nearly 6 million refugees flowing across the border in just a few weeks, but information was scarce regarding displaced and vulnerable populations who remained inside Ukraine. We leveraged social media data from Facebook's advertising platform in combination with preconflict population data to build a real‐time monitoring system to estimate subnational population sizes every day disaggregated by age and sex. Using this approach, we estimated that 5.3 million people had been internally displaced away from their baseline administrative region in the first three weeks after the start of the conflict. Results revealed four distinct displacement patterns: large‐scale evacuations, refugee staging areas, internal areas of refuge, and irregular dynamics. While the use of social media provided one of the only quantitative estimates of internal displacement in the conflict setting in virtual real time, we conclude by acknowledging risks and challenges of these new data streams for the future.

Using time travel in virtual reality (VR) to increase efficacy perceptions of influenza vaccination

Abstract This study examined the unique affordance of time travel in virtual reality (VR) to enhance the perceived efficacy of influenza vaccination. Effective vaccine communication hinges on raising awareness of the risk of contracting a contagious virus and spreading the infection to others. According to the extended-parallel process model, behavioral changes are achieved when an individual perceives sufficient levels of threat and efficacy to prevent negative health outcomes. Findings from a 2 (interactivity: active vs. passive) × 2 (virtual time travel: yes vs. no) between-subjects experiment (N = 178) indicated that virtual time travel to receive vaccination after experiencing negative consequences of influenza in VR increased participants’ perceived efficacy of vaccination for self-protection and community protection. Moreover, interactivity in VR enhanced vaccination intention, mediated by spatial presence, message involvement, and response efficacy.

A Parent-Targeted Group Intervention for Pediatric Pain Delivered In-Person or Virtually: Feasibility, Acceptability, and Effectiveness.

Parents play integral roles in their youth's chronic pain and can experience elevated distress related to caregiving. This study examined a cognitive-behavior therapy-based parent-targeted group intervention, including understudied/novel resilience/risk (eg, distress, parenting self-regulation), and compared the effect of in-person versus virtual delivery format. (1) Adequate feasibility and acceptability (enrolment>33%, attendance >60%, attrition <25%, satisfaction ratings >90%), with higher indicators of feasibility in the virtual groups; (2) Significant improvements in parent psychological flexibility, protectiveness, distress, and parenting self-regulation at posttreatment that were maintained at follow-up, with no difference between delivery type. Parents were enroled from an outpatient pediatric chronic pain clinic and participated in the group intervention in-person or virtually; questionnaires were completed at baseline, posttreatment, and 3-month follow-up. Enrolment (55% in-person, 65% virtual) and attendance (86% in-person, 93% virtual) were higher, and attrition was lower than expected (4% in-person, 7% virtual). Satisfaction was high (4.95/5 in-person, 4.85/5 virtual); on written feedback, parents enjoyed connecting with other parents (27/56, 48%) the most. The least preferred were the virtual format (5/36, 14%) and timing of the group (6/52, 12%). There were no differences between delivery formats in feasibility/acceptability. The intervention significantly improved parents' psychological flexibility, protectiveness, distress, and parenting self-regulation over time. A small group difference favored the in-person format for psychological flexibility, and an interaction effect for parenting self-regulation was found. This standalone parent-targeted group intervention had positive effects on parent outcomes delivered either in-person or virtually.

An unsupervised learning damage diagnosis method based on virtual impulse response function and time series models

As it contains the inherent properties of the structure and is insensitive to variation of the input, the transmissibility function (TF) is widely used for structural damage detection under ambient excitation. However, in TF-based methods, the selection of the optimal damage sensitivity band often requires access to vibration data under different operating conditions, which is not conducive to unsupervised learning. In order to accommodate unsupervised learning and extract more damage information, this paper proposes a data-driven unsupervised damage detection method based on the virtual impulse response function (VIRF) and time series model (TSM). In this method, the VIRF is used as a damage-sensitive feature (DSF), the TSM is used for low-dimensional feature extraction of the VIRF, and the distance metric of the model coefficients is used to detect the occurrence of anomalies. The study analyses the type of TSM applied to VIRF and uses the parameter adjusted cosine similarity (PACS) as a more accurate statistical distance tool for the model coefficients. The application of two well-known benchmark structure experiments verifies the accuracy and practicality of the proposed method in damage detection under minor operational variations and ambient excitations. The comparative analysis and detection results indicate that the proposed method is advantageous in qualitatively quantifying the extent of the damage. Structural anomalies can be detected in both linear and nonlinear damage scenarios.

Structure-Based Virtual Screening of Furan-1,3,4-Oxadiazole Tethered N-phenylacetamide Derivatives as Novel Class of hTYR and hTYRP1 Inhibitors.

Human tyrosinase (hTYR) is a key and rate-limiting enzyme along with human tyrosinase-related protein-1 (hTYRP1), which are among the most prominent targets of inhibiting hyper pigmentation and melanoma skin cancer. In the current in-silico computer-aided drug design (CADD) study, the structure-based screening of sixteen furan-1,3,4-oxadiazole tethered N-phenylacetamide structural motifs BF1-BF16 was carried out to assess their potential as hTYR and hTYRP1 inhibitors. The results revealed that the structural motifs BF1-BF16 showed higher binding affinities towards hTYR and hTYRP1 than the standard inhibitor kojic acid. The most bioactive lead furan-1,3,4-oxadiazoles BF4 and BF5 displayed stronger binding in affinities (-11.50 kcal/mol and -13.30 kcal/mol) than the standard drug kojic acid against hTYRP1 and hTYR enzymes, respectively. These were further confirmed by MM-GBSA and MM-PBSA binding energy computations. The stability studies involving the molecular dynamics simulations also provided stability insights into the binding of these compounds with the target enzymes, wherein it was found that they remain stable in the active sites during the 100 ns virtual simulation time. Moreover, the ADMET, as well as the medicinal properties of these novel furan-1,3,4-oxadiazole tethered N-phenylacetamide structural hybrids, also showed a good prospect. The excellent in-silico profiling of furan-1,3,4--oxadiazole structural motifs BF4 and BF5 provide a hypothetical gateway to use these compounds as potential hTYRP1 and hTYR inhibitors against melanogenesis.

Novel Control Theoretic Consensus-Based Time Synchronization Algorithm for WSN in Industrial Applications: Convergence Analysis and Performance Characterization

Fourth Industrial Revolution (IR4.0) depends heavily on the Internet of Things (IoT) and wireless sensor networks (WSNs). Through WSN, data in an industrial environment can be captured. Time synchronization is an important issue in WSN to ensure the correct sequence of the data collected. Besides, gauging on a common perceived time reference, local clocks on each node within any interconnected WSN should be able to initiate message exchanges. Referencing to an unsynchronized value of virtual global reference clock will render the nodes’ communication and applications in WSN useless. In this work, a newly improved control theoretic consensus-based time synchronization algorithm for WSN known as time synchronization using sliding-mode control and proportional, integral, and derivative (TSMPID) is proposed. The novel algorithm uses an augmented sliding-mode control (SMC) in the skew and relative skew estimation schemes, which is a useful switching action, to provide a salient feature in guaranteeing finite-time convergence in synchronized virtual time clock estimation. A proportional, integral, and derivative (PID) term has been introduced in the offset estimation to improve the estimation performance. The main purpose is to achieve global clock synchronization with lower computational effort and reduced synchronization error. TSMPID has the characteristics of being totally distributed, asynchronous, scalable across different network topological structures and robust to ad hoc nodes deployment. Ad hoc communication link node deployment scenarios are simulated comprising five, seven, and nine WSN nodes. TSMPID requires low energy and exhibits a much lesser consensus error spike in comparison to other recent prior-art time synchronization schemes.

Best Practices for Integration of Dissolution Data into Physiologically Based Biopharmaceutics Models (PBBM): A Biopharmaceutics Modeling Scientist Perspective

Dissolution is considered as a critical input into physiologically based biopharmaceutics models (PBBM)as it governs in vivo exposure. Despite many workshops, initiatives by academia, industry, and regulatory, wider practices are followed for dissolution data input into PBBM models. Due to variety of options available for dissolution data input into PBBM models, it is important to understand pros, cons, and best practices while using specific dissolution model. This present article attempts to summarize current understanding of various dissolution models and data inputs in PBBM software's and aims to discuss practical challenges and ways to overcome such scenarios. Different approaches to incorporate dissolution data for immediate, modified, and delayed release formulations are discussed in detail. Common challenges faced during fitting of z-factor are discussed along with novel approach of dissolution data incorporation using P-PSD model. Ways to incorporate dissolution data for MR formulations using Weibull and IVIVR approaches were portrayed with examples. Strategies to incorporate dissolution data for DR formulations wasdepicted along with practical aspects. Approaches to generate virtual dissolution profiles, using Weibullfunction, DDDPlus, and time scaling for defining dissolution safe space, and strategies to generate virtual dissolution profiles for justifying single and multiple dissolution specifications were discussed. Finally, novel ways to integrate dissolution data for complex products such as liposomes, data from complex dissolution systems, importance of precipitation, and bio-predictive ability of QC media for evaluation of CBA's impact were discussed. Overall, this article aims to provide an easy guide for biopharmaceutics modeling scientist to integrate dissolution data effectively into PBBM models.

Simultaneous multi-target ultrasound neuromodulation in freely-moving mice based on a single-element ultrasound transducer

Objective. Ultrasound neuromodulation has become an emerging method for the therapy of neurodegenerative and psychiatric diseases. The phased array ultrasonic transducer enables multi-target ultrasound neuromodulation in small animals, but the relatively large size and mass and the thick cables of the array limit the free movement of small animals. Furthermore, spatial interference may occur during multi-target ultrasound brain stimulation with multiple micro transducers. Approach. In this study, we developed a miniature power ultrasound transducer and used the virtual source time inversion method and 3D printing technology to design, optimize, and manufacture the acoustic holographic lens to construct a multi-target ultrasound neuromodulation system for free-moving mice. The feasibility of the system was verified by in vitro transcranial ultrasound field measurements, in vivo dual-target blood-brain barrier (BBB) opening experiments, and in vivo dual-target ultrasound neuromodulation experiments. Main results. The developed miniature transducer had a diameter of 4.0 mm, a center frequency of 1.1 MHz, and a weight of 1.25 g. The developed miniature acoustic holographic lens had a weight of 0.019 g to generate dual-focus transcranial ultrasound. The ultrasonic field measurements’ results showed that the bifocal’s horizontal distance was 3.0 mm, the −6 dB focal spot width in the x-direction was 2.5 and 2.25 mm, and 2.12 and 2.24 mm in the y-direction. Finally, the in vivo experimental results showed that the system could achieve dual-target BBB opening and ultrasound neuromodulation in freely-moving mice. Significance. The ultrasonic neuromodulation system based on a miniature single-element transducer and the miniature acoustic holographic lens could achieve dual-target neuromodulation in awake small animals, which is expected to be applied to the research of non-invasive dual-target ultrasonic treatment of brain diseases in awake small animals.

Development of the system for observing virtual real time lessons in physical education (SOVRTL-PE): A tool to support preservice teachers’ applied learning experiences

In tandem with increased reliance on virtual teaching in K-12 schools, the purpose of this study was to develop a systematic observation instrument – the System for Observing Virtual Real Time Lessons in Physical Education (SOVRTL-PE) – to support teacher candidates' development of distance-delivery teaching skills during preservice training. SOVRTL-PE is designed specifically to capture and measure recommended instructional practices for teaching synchronous online physical education (OLPE) lessons to students in K-12 school settings. Instrument development entailed steps taken to address validity and reliability. To address validity, we created an a priori conceptual framework from the literature on OLPE, drew from observations of OLPE lessons and conducted a Delphi survey. Steps taken to address reliability included devising a coding system, pilot testing the instrument, and establishing inter- and intra-observer reliability. Results supported the validity and reliability of SOVRTL-PE. This new instrument provides teacher education programs with an evidence-informed tool to optimize teacher candidates’ preparation for effectively conducting lessons when OLPE is a suitable alternative to in-person educational programming.

End-to-End Underwater Acoustic Communication Based on Autoencoder with Dense Convolution

To address the problems of the high complexity and poor bit error rate (BER) performance of traditional communication systems in underwater acoustic environments, this paper incorporates the theory of deep learning into a conventional communication system and proposes data-driven underwater acoustic filter bank multicarrier (FBMC) communications based on convolutional autoencoder networks. The proposed system is globally optimized by two one-dimensional convolutional (Conv1D) modules at the transmitter and receiver, it realizes signal reconstruction through end-to-end training, it effectively avoids the inherent imaginary interference of the system, and it improves the reliability of the communication system. Furthermore, dense-block modules are constructed between Conv1D layers and are connected across layers to achieve feature reuse in the network. Simulation results show that the BER performance of the proposed method outperforms that of the conventional FBMC system with channel equalization algorithms such as least squares (LS) estimation and virtual time reversal mirrors (VTRM) under the measured channel conditions at a certain moment in the Qingjiang River.

Challenges and Opportunities of Online Learning among Students of Central Mindanao University Philippines during COVID-19 Pandemic

The COVID-19 pandemic has affected how online learning is delivered and has become a serious worldwide health concern. This study sought to determine the opportunities and challenges of online learning faced by the undergraduate students of Central Mindanao University during the pandemic. To address this problem, a mixed research approach was used, combining a qualitative (narrative) and a quantitative non-experimental descriptive approach. The study found that the CMU students' opportunities for online learning are enhanced technical skills; avail learning resources from anywhere in the world, developed self-discipline, improved virtual classroom interaction, flexibility and time management, reduced educational cost, drive for self-motivation and lenient quality education were deemed to be beneficial. Online learning strengthened the students to analyze the subject matters thoroughly while responding in writing instead of discussing and freely picking and choosing from diverse learning approaches. However, its weaknesses are the critical communication gap between students and teachers, lack of focus, lack of social support, unhealthy online learning environment, lack of social support, technological constraints, and lack of time management. The challenges of online learning are slow and no internet connection, self-discipline, unhealthy online learning environment, fewer interactions with teachers and classmates, heavy workloads, dealing with subjects with laboratories, resistance to online learning, mental health, emotional and psychological anxieties, depression and financial constraints are found to be the challenges and barriers in online learning.

Stability Criterion and Frequency-domain Approximate Model Matching Based on V-Tiger

FRIT and VRFT are widely applied as representatives of Data-driven control, but the actual closed-loop response cannot be predicted. Recently, Data-driven prediction methods including V-Tiger that predict the actual closed-loop response have been proposed. V-Tiger predicts the virtual frequency response and virtual time response of a closed-loop system from one-shot experimental data to read the settling time and Nyquist locus, but these readings become difficult when the noise is large. Therefore, we propose (1) a stability criterion based on the virtual time response, (2) a noise reduction method that averages multiple virtual time responses using only one-shot experimental data, and (3) a control design method to minimize cost function in frequency domain to achieve robustness against noise.

An efficient privacy-preserving point-of-interest recommendation model based on local differential privacy

With the rapid development of point-of-interest (POI) recommendation services, how to utilize the multiple types of users’ information safely and effectively for a better recommendation is challenging. To solve the problems of imperfect privacy-preserving mechanism and insufficient response-ability to complex contexts, this paper proposes a hybrid POI recommendation model based on local differential privacy (LDP). Firstly, we introduce randomized response techniques k-RR and RAPPOR to disturb users’ ratings and social relationships, respectively and propose a virtual check-in time generation method to deal with the issue of missing check-in time after disturbance. Secondly, for simultaneously combining multiple types of information, we construct a hybrid model containing three sub-models. Sub-model 1 considers the effect of user preference, social relationship, forgetting feature, and check-in trajectory on similarity calculation. Sub-model 2 analyzes the geographical correlation of POIs. Sub-model 3 focuses on the categories of POIs. Finally, we generate the recommendation results. To test the performance of privacy-preserving and recommendation, we design three groups of experiments on three real-world datasets for comprehensive verifying. The experimental results show that the proposed method outperforms existing methods. Theoretically, our study contributes to the effective and safe usage of multidimensional data science and analytics for privacy-preserving POI recommender system design. Practically, our findings can be used to improve the quality of POI recommendation services.

SA81 Feasibility and Challenges of Virtual Time Trade-Off Interviews: The Case of the EQ-5D-3L Valuation Study in Jordan

SA81 Feasibility and Challenges of Virtual Time Trade-Off Interviews: The Case of the EQ-5D-3L Valuation Study in Jordan

The Areal Project: How Virtual Reality Application Could Enhance Patient's Quality Time during Transfusion Therapy in Adult Patients with Thalassemia and Sickle Cell Disease

Background Chronic red blood cell transfusion therapy (CTT) is an integral component of the management of Transfusion Dependent Thalassemia (TDT) and Sickle Cell Disease (SCD). CTT requires time and significantly impacts the quality of life of patients with TDT and SCD. In some cases, the environment in which transfusions are performed is uncomfortable and doesn't offer adequate spaces and facilities. And as a result, the patient experiences a condition of discomfort and tries with his own means to get distracted or "estranged". Hence, attention should be paid to psychological, emotional and social needs of patients on CTT in order to reduce the burden of the procedure with activities that are capable of engaging more the person. Aims From this need and the opportunities offered by the digital technologies available today, the AREAL project was designed by the Italian startup Softcare Studios in partnership with the pharma company Novartis and in collaboration with hemoglobinopathy specialized medical staff. Objectives of this pilot project were: i) collect feedback from patients with TDT and SCD and from healthcare professional workers regarding utility and feasibility of AREAL; ii) detect and evaluate changing in states of patient's anxiety and depression. Methods AREAL consists of three gaming activities enjoyed in virtual reality thanks to the use of suitable Virtual Reality (VR) viewers (Figure 1A) developed to immerse the patient in a sensorial stimulating scenario and designed to stimulate cognitive skills: activity 1 for short-term memory, activity 2 for task switching, activity 3 for problem solving. AREAL also integrates elements of patient education in therapy and recommended lifestyle habits to promote their well-being. Anxiety and depression were assessed by a self-assessment questionnaire, the Hospital Anxiety and Depression Scale (HADS), administered after each virtual session. Results The pilot group was composed by 70 subjects on CTT followed in 3 hospital centers in Italy (Genova, Napoli, Padova). The 57% were males, median age was 31 years (IQR: 21-40), 53 patients were affected by TDT and 6 by SCD. The total number of sessions collected is 129; 59 patients experienced two sessions and were included in the analysis for HADS. The average duration of game sessions lasted 17 minutes.Activity 1 was the most played and most rarely interrupted, followed by 2 and finally by 3, where 50% of sessions are been interrupted due to its difficulty. In Activity 1 patients recognized the goal of the game, which is to stimulate memory, and they liked its immediacy. Excessive facility, especially considering the repetition over time during the therapy, was emphasized by patients who suggested making the game more complicated. Compared to Activity 1, Activity 2 is more complicated and engaging, emerging as the overall favorite of the study patients. Undoubtedly, Activity 3 emerged as the most difficult one, both to play and to understand, also given its focus on problem solving. Based on the feedback from healthcare professionals learning to use the virtual application wasn't particularly difficult. The experience of the staff confirmed some of the critical issues also communicated by patients (such as the high difficulty of the third game activity and request for greater variability over time).Anxiety and depression were detected by HADS respectively in 13 and in 9 pts after first session, in 10 and in 4 pts after second session, suggesting a possible benefit of VR; the number of patients with borderline profile reduced from 8 to 3 both for anxiety and depression (Figure 1B). There were no significant differences of scores and/or percentages between sessions. Conclusions There is a significant need to iterate AREAL on the basis of different age groups, each with specific needs, preferences and level of confidence with technologies. From the collected feedback, AREAL was perceived as an innovative project and an opportunity to pay attention to the critical issues of the patients' therapeutic experience on CTT. However, it is needed to optimize the experience in order to free the operator from extra commitments as much as possible that could impact the quality of hospital work routine. AREAL seems to be an opportunity to reduce discomfort and anxiety during CCT in the subset of pts with a profile borderline for anxiety and depression but needs to tailor the intervention to specific subsets of patients. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Walking With the ISMRM in the Footprints of Our MR History.

Walking With the ISMRM in the Footprints of Our MR History.

Hybrid time synchronization protocol for large-scale wireless sensor networks

There are two common approaches to design a time synchronization protocol as reference-based and consensus-based. The first approach is mainly employed in protocols operating in large-scale wireless sensor networks (WSNs) because of its fast convergence. However, reference-based time synchronization protocols are vulnerable to node-failure in real-world applications. Although consensus-based time synchronization protocols do not experience the aforementioned problem, they are not suitable for operation in large-scale WSNs owing to their slow convergence. In this study, we propose a hybrid time synchronization protocol (HTSP) to utilize the advantages of both approaches. In particular, HTSP exploits a temporary reference node to significantly reduce the convergence time and employs average-based consensus during normal operation to cope with node failures. It is notable that each node in HTSP can seamlessly switch between the reference and consensus modes during its operation. Moreover, HTSP is a fully distributed protocol as it does not rely on any leader-election mechanism. Our simulation results demonstrated that HTSP outperforms flooding, gradient, and virtual link-based time synchronization protocols considering various types of network topologies and scales.