Hierarchical Optimization Model Based on V2G Technology

Large-scale electric vehicle (EV) random access to the power grid, the load peak-valley difference will become larger, seriously affect the stable operation of the power grid. In this paper, a V2G based bi-level optimal scheduling model for EV charging and discharging is proposed. The upper model takes the minimum variance of the total load as the objective function, and the lower model takes the increase of user participation and the maximization of user revenue as the objective function. The multi-population genetic algorithm is used to analyze the model, and the results show that the model can not only smooth the load fluctuation, effectively reduce the load peak-valley difference, but also maximize the economic benefits of users participating in V2G service.

Spatio-Temporal Modeling of Immune Response to SARS-CoV-2 Infection

COVID-19 is a disease occurring as a result of infection by a novel coronavirus called SARS-CoV-2. Since the WHO announced COVID-19 as a global pandemic, mathematical works have taken place to simulate infection scenarios at different scales even though the majority of these models only consider the temporal dynamics of SARS-COV-2. In this paper, we present a new spatio-temporal within-host mathematical model of COVID-19, accounting for the coupled dynamics of healthy cells, infected cells, SARS-CoV-2 molecules, chemokine concentration, effector T cells, regulatory T cells, B-lymphocytes cells and antibodies. We develop a computational framework involving discretisation schemes for diffusion and chemotaxis terms using central differences and midpoint approximations within two dimensional space combined with a predict–evaluate–correct mode for time marching. Then, we numerically investigate the model performance using a list of values simulating the baseline scenario for viral infection at a cellular scale. Moreover, we explore the model sensitivity via applying certain conditions to observe the model validity in a comparison with clinical outcomes collected from recent studies. In this computational investigation, we have a numerical range of 104 to 108 for the viral load peak, which is equivalent to what has been obtained from throat swab samples for many patients.

In vivo analysis of hip joint loading on Nordic walking novices

Objective To evaluate the influence of Nordic walking (NW) on hip joint loads in order to determine whether it can be safely performed during postoperative physiotherapy in patients after orthopeadic surgery of the hip. Methods Internal hip joint loads were directly measured in vivo in 6 patients using instrumented hip prostheses during NW and ordinary walking (OW). All patients received training in two different NW techniques (double-poling and the diagonal technique) by a certified NW instructor. Measurements were conducted on a treadmill at a speed of 4 km/h on level ground, at 10% inclination and at 10% slope as well as on a level lawn at a self chosen comfortable speed. Resultant contact force (Fres), bending moment (Mbend) and torsional torque (Mtors) were compared between NW and OW as well as between both NW techniques. Results Joint loads showed a double peak pattern during all setups. Neither NW technique significantly influenced hip joint loads at the time of the first load peak during contralateral toe-off (CTO), which was also the absolute load peak, in comparison to OW. Compared to OW, double-poling significantly reduced Fres and Mbend at the time of the second load peak during the contralateral heel strike (CHS) on level ground both on the treadmill (− 6% and − 7%, respectively) and on the lawn (− 7% and − 9%). At 10% inclination, the diagonal technique increased Fres and Mbend at CHS (by + 6% and + 7%), but did not increase the absolute load peak at CTO. Conclusion Joint loads during NW are comparable to those of OW. Therefore, NW can be considered a low-impact activity and seems to be safe for patients that are allowed full weight bearing, e.g. during postoperative rehabilitation after THA.

Trajectory of viral load in a prospective population-based cohort with incident SARS-CoV-2 G614 infection

Importance: SARS-CoV-2 viral trajectory has not been well-characterized in documented incident infections. These data will inform SARS-CoV-2 natural history, transmission dynamics, prevention practices, and therapeutic development. Objective: To prospectively characterize early SARS-CoV-2 viral shedding in persons with incident infection. Design: Prospective cohort study. Setting: Secondary data analysis from a multicenter study in the U.S. Participants: The samples derived from a randomized controlled trial of 829 community-based asymptomatic participants recently exposed (<96 hours) to persons with SARS-CoV-2. Participants collected daily mid-turbinate swabs for SARS-CoV-2 detection by polymerase-chain-reaction and symptom diaries for 14-days. Persons with negative swab for SARS-CoV-2 at baseline who developed infection during the study were included in the analysis. Exposure: Laboratory-confirmed SARS-CoV-2 infection. Main outcomes and measures: The observed SARS-CoV-2 viral shedding characteristics were summarized and shedding trajectories were examined using a piece-wise linear mixed-effects modeling. Whole viral genome sequencing was performed on samples with cycle threshold (Ct)<34. Results: Ninety-seven persons (57% women, median age 37-years) developed incident infections during 14-days of follow-up. Two-hundred fifteen sequenced samples were assigned to 15 lineages that belonged to the G614 variant. Forty-two (43%), 18(19%), and 31(32%) participants had viral shedding for 1 day, 2-6 days, and >7 days, with median peak viral load Ct of 38.5, 36.7, and 18.3, respectively. Six (6%) participants had 1-6 days of observed viral shedding with censored duration. The peak average viral load was observed on day 3 of viral shedding. The average Ct value was lower, indicating higher viral load, in persons reporting COVID-19 symptoms than asymptomatic. Using the statistical model, the median time from shedding onset to peak viral load was 1.4 days followed by a median of 9.7 days before clearance. Conclusions and Relevance: Incident SARS-CoV-2 G614 infection resulted in a rapid viral load peak followed by slower decay and positive correlation between peak viral load and shedding duration; duration of shedding was heterogeneous. This longitudinal evaluation of the SARS-CoV-2 G614 variant with frequent molecular testing may serve as a reference for comparing emergent viral lineages to inform clinical trial designs and public health strategies to contain the spread of the virus.

The timing of natural killer cell response in coronavirus infection: a concise model perspective

Coronaviruses, including SARS-CoV, MERS-CoV, and SARS-CoV-2 cause respiratory diseases with remarkably heterogeneous progression. This in part reflects the viral ability to influence the cytokine secretion and thereby the innate immune system. Especially the viral interference of IFN-I signaling and the subsequent deficiency of innate immune response in the early phase have been associated with rapid virus replication and later excessive immune responses. We propose a mathematical framework to analyze IFN-I signaling and its impact on the interaction motif between virus, NK cells and macrophages. The model recapture divergent dynamics of coronavirus infections including the possibility for elevated secretion of IL-6 and IFN-γ as a consequence of exacerbated macrophage activation. Dysfunction of NK cells recruitment increase disease severity by leading to a higher viral load peak, the possibility for excessive macrophage activation, and an elevated risk of the cytokine storm. Thus the model predicts that delayed IFN-I signaling could lead to pathogenicity in the latter stage of an infection. Reversely, in case of strong NK recruitment from infected cells we predict a possible chronic disease state with moderate and potentially oscillating virus/cytokine levels.

Integrating External and Internal Load for Monitoring Fitness and Fatigue Status in Standard Microcycles in Elite Rink Hockey

The aims of this study were 3-fold: firstly, to present an integrative approach to external and internal load dynamics for monitoring fitness and fatigue status of specific in-court rink hockey training sessions in a standard microcycle; secondly, to assess the differences between training sessions and matches; the third and final aim was to assess the association between external and internal load metrics. The external load, using a local positioning system, and internal load, using the declared rate of perceived exertion, were measured during 23 in-season microcycles for nine top-level players. Training load data were analysed with regard to the number of days before or after a match [match day (MD) minus or plus]. In relation to the first aim, internal and external load metrics merged into a single integrated system using pooled data z-scores provided an invisible monitoring tool that places the players in the fitness-fatigue continuum throughout the different microcycle sessions. In this regard, MD-4 and MD-1 sessions tend to place, with a low dispersion, the players in a “low external and internal load” zone. On the contrary, in MD-3 and MD-2 sessions, as well as in MD, in which higher loads were recorded, most of the players were within a “high external and internal load” zone with a tendency towards dispersion towards the fitness or fatigue zones. Finally, and with regard to the second and third aims, an inverted “U-shape” load dynamic related to the specific goals of each training session was the main finding in terms of comparison between MD; a load peak between MD-3 and MD-2 sessions and a significant decrease in all the load variables in MD-1 sessions were found; and high-to-low correlations were found between external and internal load metrics. This study presents an integrative approach to the external and internal load of players for monitoring fitness and fatigue status during a standard microcycle in rink hockey that might provide team sport staff members with a deeper understanding of load distribution in the microcycle in relation to the match.

Performance of Ground Anchored Walls Subjected to Dynamic and Pseudo-Static Loading

This study investigates the response of pre-stressed anchored excavation walls under dynamic and pseudo-static loadings. A finite difference numerical model was developed using FLAC2D, and the results were successfully validated against full-scale experimental data. Analyses were performed on 10, and 20-m-height stabilized excavated slopes with 60° to 90° of inclination angle with the horizon to represent an applicable variety of wall geometries. In dynamic analysis, the statically stabilized models were subjected to 0.2 to 0.6g of the dynamic peak acceleration to evaluate the effect of ground acceleration on their performance. Furthermore, pseudo-static analyses were performed on the statically stabilized models with pseudo-static coefficients ranging from 0.06 to 0.22. The results revealed that ground anchored slopes generally showed acceptable performances under dynamic loading, while higher axial forces were induced to ground anchors in higher and steeper models. Furthermore, comparing the results of dynamic and pseudo-static analyses showed a good agreement between the two methods' predictions in the mobilized axial force along the ground anchors. Pseudo-static coefficients were then proposed to replicate dynamic results, considering the slope geometry and dynamic load peak acceleration. The results revealed that higher and steeper stabilized slopes required higher values of pseudo-static coefficients to match the dynamic predictions successfully. The results indicate that pseudo-static coefficient tend to increase with the increase in dynamic load peak acceleration in any given model. Doi: 10.28991/cej-2021-03091703 Full Text: PDF

CLOUD STORAGE DENGAN TEKNOLOGI KUBERNETES UNTUK PLATFORM COLLABORATIVE RESEARCH

Memberikan model alternatif untuk penerapan penelitian kolaboratif melalui layanan teknologi komputasi awan yang diim- plementasikan di lingkungan komputer lokal atau untuk menampung penyimpanan file di luar lokasi, penggunaan berbagi file cloud sangat bermanfaat dan mudah. Penggunaan teknologi ini harus diimplementasikan dan diuji keandalannya dalam skala yang baik sehingga jika akan dikembangkan lebih lanjut dapat segera diimplementasikan dan sesuai dengan lingkungan dan sumber daya jaringan yang ada. Penelitian ini berfokus pada implementasi dan pengujian performa kecepatan dan user request yang menghasilkan nilai A pada uji kecepatan pada GTMetrix dan load peak tertinggi connection time 0-5ms. Solusi terhadap penurunan performa dapat disolusikan dengan menggunakan model scaling dikombinasikan dengan proxy, dan load balancing.