Bike-Sharing Fleet Allocation Optimization Based on Demand Gap and Cycle Rebalancing Strategies

In Bike-Sharing System (BSS), the initial number of bikes at station will affect the time interval and the amount of rebalancing, which is usually empirically determined and does not reflect the characteristics of consumer demand in finer time granularity, thus possibly leading to biased conclusions. In this paper, a fleet allocation method considering demand gap is first proposed to calculate the initial number of bikes at each station. Then, taking the number of demand gap periods as the decision variable, an optimization model is built to minimize the total rebalancing amount. Furthermore, the research periods are divided into multiple subcycles, the single-cycle and multicycle rebalancing strategies are presented, and the additional subcycle rebalancing method is introduced to amend the number of bikes between subcycles to decrease the rebalancing amount of the next subcycle. Finally, our methods are verified in effectively decreasing the rebalancing amount in a long-term rebalancing problem.

Characteristics of Canadian Veterans reimbursed for cannabis for medical purposes: Life After Service Survey 2016

LAY SUMMARY This research explored the demographic, military service, and health characteristics associated with cannabis for medical purposes (CMP) reimbursements among Veterans Affairs Canada (VAC) clients and respondents of the Life After Service Survey 2016 (LASS). Of the initial number of indicators selected contained in LASS 2016 survey, some specific variables were significantly associated with CMP reimbursement, from which physical/mental health and well-being indicators, such as anxiety, posttraumatic stress disorder (PTSD), depression, bowel ulcer, traumatic brain injury, chronic pain, needing help with tasks, psychological distress, and having three of more conditions of the PTSD diagnosis, were positively associated with CMP. Moreover, unemployment, having low income (< $5,000), a difficult adjustment, being very dissatisfied with life, having low social support, a weak community belonging, and reporting high stress also increased the odds of being reimbursed. These results will help to identify a preliminary profile of VAC clients with higher need for CMP reimbursement.

Large Fork-Join Queues with Nearly Deterministic Arrival and Service Times

In this paper, we study an N server fork-join queue with nearly deterministic arrival and service times. Specifically, we present a fluid limit for the maximum queue length as [Formula: see text]. This fluid limit depends on the initial number of tasks. In order to prove these results, we develop extreme value theory and diffusion approximations for the queue lengths.

Collective Reactions to Epidemic Threat: Attachment and Cultural Orientations Predict Early COVID-19 Infection and Mortality Rates and Trajectories

Hypotheses on culture-level attachment and individualism/collectivism relationships with COVID-19 infection and death rates during a period at the beginning of the epidemic were tested in data from 53 countries and 50 U.S. states. Results from multilevel growth curve analyses showed group-average anxious attachment predicted a lower initial number of cases and deaths cross-culturally and in the United States, while avoidant attachment predicted a higher initial number of COVID-19 infections in the United States and a higher initial number of deaths in both studies. Yet, during this period, culture-level anxious attachment was associated with a higher growth rate of infections and deaths, while a lower growth rate of infections and deaths was observed in countries and U.S. states with higher individualism and avoidance. The research provides new insights into attachment and culture relationships and points to different mechanisms that may explain initial and growth rate trajectories at the beginning of the epidemic.

Implementation of Multiple-Representation Approaches Based on E-Module to Reduce Misconceptions of Prospective Physics Teachers During the Covid-19 Pandemic

One of the problems that are often found in universities, especially in physics subjects, is the existence of misconceptions in students (learners). This study aims to determine the effectiveness of using the multiple-representation approach Based on E-Module in reducing the misconceptions of prospective physics teachers during the Covid-19 pandemic. The method used is quantitative research with a one-group pretest-posttest design. The sample consisted of 25 prospective physics teachers at one of the universities in the city of Mataram. The instrument used in this research is an open-ended three-tier test. A total of 10 test items with 30 questions were used in this study. The test was given twice, namely before and after treatment. The test results data were then analyzed using descriptive statistics to determine the decrease in the percentage of students who experienced misconceptions. Based on the results of data analysis shows that there is a decrease in the percentage of students who experience misconceptions by 31.89% from the initial number of 57.19 to 25.30%. This decrease in misconceptions was also followed by an increase in the percentage of students who understood the concept from 18.14 to 72.38%. Thus, it can be concluded that the application of the multiple representation approach assisted by E-Modules can be used as an alternative to reduce misconceptions and improve understanding of the concept of prospective physics teachers in the COVID-19 pandemic

Recombination of Poly(Acrylic Acid) Radicals in Acidic Aqueous Solutions: A Pulse Radiolysis Study

Carbon-centered radicals have been randomly generated on the chains of poly(acrylic acid), PAA, the simplest synthetic anionic polyelectrolyte, by pulse-irradiating its dilute, oxygen-free aqueous solutions by 6 MeV electron beam. In some experiments, oligo(acrylic acid), OAA, and propionic acid, PA, were used as PAA models. Recombination kinetics of PAA radicals has been followed by fast spectrophotometry. A strong pH dependence of radical lifetime on pH, and thus on the linear charge density due to deprotonated carboxylate groups, has been confirmed, while a weaker amplitude of pH dependence was observed for OAA and PA. Decay kinetics of PAA radicals in the protonated state, at pH 2, have been studied in some detail. At moderate doses of ionizing radiation, resulting in a moderate average initial number of radicals per chain, ZR0, the decay can be satisfactorily described by a second-order kinetic model, but a somewhat better fit is obtained by using a dispersive kinetics approach. While for a constant polymer concentration the reciprocal half-lives are proportional to the initial radical concentrations, such a data series for different PAA concentrations do not overlap, indicating that the overall radical concentration is not the decisive factor controlling the kinetics. Arranging all data, in the form of second-order rate constants, as a function of the average initial number of radicals per chain allows one to obtain a common dependence. The latter seems to consist of two parts: a horizontal one at low ZR0 and another one of positive slope at higher ZR0. This is interpreted as two kinetic regimes where two distinct reactions dominate, intermolecular and intramolecular recombination, respectively. Comparison of the low ZR0 data with calculations based on the translational diffusion model indicate that the latter is not the rate-controlling process in intermolecular recombination of polymer radicals; segmental diffusion is the more likely candidate.

Modeling and analysis of COVID-19 infected persons during repeated waves in Japan

A model for estimating the number of COVID-19 infected persons (infecteds) is proposed based on the exponential function law of the SIR model. This model is composed of several equations expressing the number of infecteds, considering the onset after an incubation period, infectivity, wavy infection persistence with repeated infection spread and convergence with insufficient quarantine. This model is applied to the infection in Japan, which is currently suffering from the 5th wave, and the initial number of infecteds and various related parameters are calculated by curve fitting of the cumulative number of infecteds to the total cases in the database. As a minimum boundary of the number of infecteds for the infection continuation up to the 5th wave, the initial number of infecteds at the outbreak of infection is more than an order of magnitude higher than the actual initial cases. A convergence ratio (cumulative number of infecteds / total cases) at the end of the first wave is obtained as 1.5. The quarantine rate and social distancing ratio based on the SIQR model are evaluated, and the social distancing ratio increases sharply just after the government's declaration of emergency. The quarantine rate closely equals the positive rate by PCR tests, meaning that the number of infecteds, which had been unknown, is on the order of almost the same as the number of tests.

Standardizing Components and Rotating Workers Using GT-Based Algorithm—A Case Study

In both manufacturing and remanufacturing systems, exploiting bulk buying and avoiding delivery delays due to material shortages are crucial. One method that aids in these processes is component standardization. Additionally, company managers seek to reduce labor costs and mitigate the risk of sudden worker resignation or absence due to, for example, reasons associated with the COVID-19 pandemic. The aforementioned problems could be solved using the sorting algorithm proposed in this study. The concept of the proposed algorithm is based on group technology. One numerical example and two case studies are presented to demonstrate the utility of the proposed algorithm. The first example suggested that the performance of the algorithm proposed in this study is superior to another one in the literature. The second one demonstrated that the algorithm in this work achieves component standardization by reducing an initial number of 12 components down to 6. The final case study provides an effective means of grouping workers with similar operational abilities and suggests how to assign new tasks to other skilled workers if a worker resigns suddenly or cannot attend work due to pandemic prevention measures.

Influence of the Initial Cell Number on the Growth Fitness of Salmonella Enteritidis in Raw and Pasteurized Liquid Whole Egg, Egg White, and Egg Yolk

Salmonella growth in egg and egg products has been widely studied, but there are still some aspects that are not fully known. The objective of this work was to study the influence of the initial cell number on the growth fitness of Salmonella Enteritidis in raw and pasteurized egg products. Growth curves of five Salmonella Enteritidis strains in raw and pasteurized egg products, starting from different initial numbers, were obtained and fitted to the Baranyi and Roberts model. The results revealed that lower initial numbers led to longer lag phases (λ) and lower maximum specific growth rates (μmax) in raw liquid whole egg. Similar results were observed in raw egg white (except for one strain). Conversely, no influence (p > 0.05) of the initial concentration on Salmonella growth parameters in raw egg yolk was observed. On the other hand, no influence of the initial number of cells on Salmonella growth fitness in commercial pasteurized liquid whole egg was observed. The results obtained demonstrate that the disappearance of this initial-dose dependency phenomenon was dependent on the intensity of the thermal treatment applied. Finally, the influence of the initial number was, in general, lower in pasteurized than in raw egg white, but large differences among strains were observed.