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Author(s):  
Xue Jia ◽  
Dan-Yang Lv ◽  
Yang Hu ◽  
Ji-Bo Wang ◽  
Zhi Wang ◽  
...  

This paper studies the slack due-window assignment scheduling problem with deterioration effects and a deterioration maintenance activity on a single-machine. The machine deteriorates during the machining process, and at a certain moment performs a deterioration maintenance activity, that is, the duration time of the maintenance activity is a linear function of the maintenance starting time. It is needed to make a decision on when to schedule the deteriorating maintenance activity, the optimal common flow allowances and the sequence of jobs to minimize the weighted penalties for the sum of earliness and tardiness, weighted number of early and delayed, and weighted due-window starting time and size. This paper proposes a polynomial time algorithm to solve this problem.


2022 ◽  
Vol 307 ◽  
pp. 79-87
Author(s):  
Leah Epstein ◽  
Asaf Levin

Author(s):  
Xiao Wu ◽  
Peng Guo ◽  
Yi Wang ◽  
Yakun Wang

AbstractIn this paper, an identical parallel machine scheduling problem with step-deteriorating jobs is considered to minimize the weighted sum of tardiness cost and extra energy consumption cost. In particular, the actual processing time of a job is assumed to be a step function of its starting time and its deteriorating threshold. When the starting time of a job is later than its deteriorating threshold, the job faces two choices: (1) maintaining its status in holding equipment and being processed with a base processing time and (2) consuming an extra penalty time to finish its processing. The two work patterns need different amounts of energy consumption. To implement energy-efficient scheduling, the selection of the pre-processing patterns must be carefully considered. In this paper, a mixed integer linear programming (MILP) model is proposed to minimize the total tardiness cost and the extra energy cost. Decomposition approaches based on logic-based Benders decomposition (LBBD) are developed by reformulating the studied problem into a master problem and some independent sub-problems. The master problem is relaxed by only making assignment decisions. The sub-problems are to find optimal schedules in the job-to-machine assignments given by the master problem. Moreover, MILP and heuristic based on Tabu search are used to solve the sub-problems. To evaluate the performance of our methods, three groups of test instances were generated inspired by both real-world applications and benchmarks from the literature. The computational results demonstrate that the proposed decomposition approaches can compute competitive schedules for medium- and large-size problems in terms of solution quality. In particular, the LBBD with Tabu search performs the best among the suggested four methods.


PLoS ONE ◽  
2021 ◽  
Vol 16 (12) ◽  
pp. e0261049
Author(s):  
Kathleen Campbell ◽  
Nicole Cosenza ◽  
Robert Meech ◽  
Michael Buhnerkempe ◽  
Jun Qin ◽  
...  

Objective Determine effective preloading timepoints for D-methionine (D-met) otoprotection from steady state or impulse noise and impact on cochlear and serum antioxidant measures. Design D-met started 2.0-, 2.5-, 3.0-, or 3.5- days before steady-state or impulse noise exposure with saline controls. Auditory brainstem response (ABRs) measured from 2 to 20 kHz at baseline and 21 days post-noise. Samples were then collected for serum (SOD, CAT, GR, GPx) and cochlear (GSH, GSSG) antioxidant levels. Study sample Ten Chinchillas per group. Results Preloading D-met significantly reduced ABR threshold shifts for both impulse and steady state noise exposures but with different optimal starting time points and with differences in antioxidant measures. For impulse noise exposure, the 2.0, 2.5, and 3.0 day preloading start provide significant threshold shift protection at all frequencies. Compared to the saline controls, serum GR for the 3.0 and 3.5 day preloading groups was significantly increased at 21 days with no significant increase in SOD, CAT or GPx for any impulse preloading time point. Cochlear GSH, GSSG, and GSH/GSSG ratio were not significantly different from saline controls at 21 days post noise exposure. For steady state noise exposure, significant threshold shift protection occurred at all frequencies for the 3.5, 3.0 and 2.5 day preloading start times but protection only occurred at 3 of the 6 test frequencies for the 2.0 day preloading start point. Compared to the saline controls, preloaded D-met steady-state noise groups demonstrated significantly higher serum SOD for the 2.5–3.5 day starting time points and GPx for the 2.5 day starting time but no significant increase in GR or CAT for any preloading time point. Compared to saline controls, D-met significantly increased cochlear GSH concentrations in the 2 and 2.5 day steady-state noise exposed groups but no significant differences in GSSG or the GSH/GSSG ratio were noted for any steady state noise-exposed group. Conclusions The optimal D-met preloading starting time window is earlier for steady state (3.5–2.5 days) than impulse noise (3.0–2.0). At 21 days post impulse noise, D-met increased serum GR for 2 preloading time points but not SOD, CAT, or GpX and not cochlear GSH, GSSG or the GSH/GSSG ratio. At 21 days post steady state noise D-met increased serum SOD and GPx at select preloading time points but not CAT or GR. However D-met did increase the cochlear GSH at select preloading time points but not GSSG or the GSH/GSSG ratio.


2021 ◽  
Vol 33 (3) ◽  
pp. 167-177
Author(s):  
Hussein Khmais Hussein

          The researcher, through his work as a coach in some Iraqi weightlifting clubs, noticed hesitation in time administration during training sessions of clubs and league. He noticed that so much time is spend on details not related to the training program thus, he aimed at identifying the variables of the research through designing data registration form that includes all these variables (delays like wearing Band-Aids, drinking water, starting time after coach’s whistle, exercises timing and, moving from one exercise to the other). A comparison was made between two different training administrations after the first beginning procedures, after it, and during two different times. The results showed significant differences between the two administrations in time investment in favor of the training procedure.


2021 ◽  
Vol 108 (Supplement_6) ◽  
Author(s):  
A Connelly ◽  
T Ton

Abstract Aim Providing high quality teaching has become increasingly difficult as social distancing and disrupted schedules caused by the COVID-19 pandemic make large in-person gatherings impractical. Yet the need and demand for this has only increased. We sought to use an innovative virtual + in-person format to facilitate delivery. Method We designed a 6-session ENT teaching programme for GP trainees over 3 evenings. Each session was consultant-led, delivered in-person in a large lecture theatre, and simultaneously broadcast on Microsoft Teams. The in-person element was intended to permit practical demonstrations, e.g., of the Dix-Hallpike test, to supplement presenter’s videos. Attendees could attend in-person or virtually. Sessions were timed to allow staff from the nearby hospital to join immediately after work. Results All attendees attended virtually. And all felt that the video demonstrations were sufficient, and that in-person replication was unnecessary. Course delivery was rated ‘very good’ or ‘excellent’ by 88% (n = 17), and the course overall was rated similarly by 94%. Several comments suggested that in future we focus on virtual delivery by shifting the starting time later to “allow a natural break after work”. Conclusions The COVID-19 pandemic has altered many aspects of our lives, and teaching delivery is not immune to this. The overwhelming preference for virtual attendance amongst our cohort suggests that many doctors are comfortable with, and even enthusiastic for, this change, and that teaching can still be effective. Future iterations of this course will likely emphasise the virtual element and record the sessions to allow for time-shifted viewing.


Atmosphere ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 952
Author(s):  
Lili Yang ◽  
Shuwen Zhang ◽  
Zhongwei Huang ◽  
Yanping Yang ◽  
Lina Wang ◽  
...  

As the main source of dust in Asia, China often suffers from dust events. The temporal and spatial characteristics of dust events change with the variations of geography, climate and human activities. Based on the criteria of selecting dust events proposed recently by the China Environmental Monitoring Station, the hourly concentration of PM10 and PM2.5 of 336 cities in China from 2015 to 2020 were used to study the temporal and spatial characteristics of dust events more accurately and objectively. The results showed that all of the dust events in China clearly decreased, but the strong dust events did not decrease. There were 334 cities that had dust events except Shenzhen and Dongguan, 299 cities were seriously polluted due to dust events, 134 cities encountered dust level III and 56 cities encountered dust level IV. The high frequencies of dust events were mainly distributed in Northern China, especially in Northwest China. The dust contribution of PM10 to the cities in Northwest China was more than 10% and about 5–10% for PM2.5. The most likely month for dust was May. The starting time of dust was bimodally distributed, and the most common starting time was 10:00–11:00 BJT, followed by 22:00–23:00 BJT. According to the PSCF (Potential Source Contribution Function) results, the dust potential source contribution of different cities mainly came from the northwest, and was mainly affected by Mongolia in addition to the local dust in China. In addition, Beijing was obviously affected by dust recirculation. This study is of great significance to the improvement of the forecast of dust weather and the warning of heavy pollution caused by dust events.


2021 ◽  
Author(s):  
Mai He ◽  
Li Li ◽  
Weisi Yan ◽  
Louis P. Dehner ◽  
Lucia F. Dunn

Abstract Objective:China’s COVID-19 statistics fall outside of recognized and accepted medical norms. Here we estimated the incidence, death and starting time of the COVID-19 outbreak in Wuhan and China based on cremation related information. Methods: Data sources included literature on COVID-19 in China, official Chinese government figures, and media reports. A range of estimates is presented by an exponential growth rate model. Results:For the cumulative infections and total deaths, under different assumptions of case fatality rates (from 2.5% to 10%) and doubling time 6.4 days, the estimates projected on February 7, 2020 in Wuhan range from 305,000 to 1,272,000 for infections and from 6,811 to 7,223 for deaths - on the order of at least 10 times the official figures (13,603 and 545). The implied starting time of the outbreak is October 2019. The estimates of cumulative deaths, based on both funeral urns distribution and continuous full capacity operation of cremation services up to March 23, 2020, give results around 36,000, more than 10 times of the official death toll of 2,524. Conclusions:Our study indicates a potential significant under- and delayed reporting in Chinese official data on the COVID-19 epidemic in Wuhan in early February, 2020.


2021 ◽  
Vol 9 (6) ◽  
pp. 242-255
Author(s):  
Y. V. Subba Rao

The starting time or commencement of , an annual festival, at the Lord Venkateswara Temple at , celebrated by (TTD) is a total deviation from injunction whereas an additional festival celebrated in an once in three years comes unaware in total conformity with prescription of the ‘ time” for the commencement of this most sacred and important temple ritual. The rectification of the deviation occurring due to the erroneous astronomical positions of planets, the Sun and the Moon, in the Luni-Solar Indian almanac (TTD ) is discussed here with a suggestion of rectification of in the “ Time” for the of the Planet and all life living on it.


2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Yushan Liu ◽  
Huijuan Dong ◽  
Liang Wang

The automatic segmentation and classification of an unknown motion data stream based on given motion classes constitute an important research problem with applications in computer vision, animation, healthcare, and sports sciences. In this paper, the scenario of trampoline motions is considered, where an athlete performs a routine consisting of sequence of jumps that belong to predefined motion classes such as somersaults. The purpose of this study was to make theoretical discussions on the turning starting time and starting technique of trampoline somersault based on image recognition and point out that the appropriate turning starting time of trampoline somersault is the event when the spring net of the trampoline recovers and applies force to the human body, and the overturning start exists in the latter half of the take-off action. It is considered that how to obtain the ideal full reaction force of the net facing the human body is the flip starting technique. This work analyzes the key steps and events for trampoline somersaults and the application of artificial intelligence for the recognition of actions in the healthcare and sports fields. The effectiveness of the proposed study is shown through experimental results. The study can facilitate the process of recognition of trampoline somersault.


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