Human mobility models reveal the underlying mechanism of seasonal movements across China

Author(s):  
Bing Song ◽  
Xiao-Yong Yan ◽  
Suoyi Tan ◽  
Bin Sai ◽  
Shengjie Lai ◽  
...  

Understanding the spatial interactions of human mobility is crucial for urban planning, traffic engineering, as well as for the prevention and control of infectious diseases. Although many models have been developed to model human mobility, it is not clear whether such models could also capture the traveling mechanisms across different time periods (e.g. workdays, weekends or holidays). With one-year long nationwide location-based service (LBS) data in China, we investigate the spatiotemporal characteristics of population movements during different time periods, and make thorough comparisons for the applicability of five state-of-the-art human mobility models. We find that population flows show significant periodicity and strong inequality across temporal and spatial distribution. A strong “backflow” effect is found for cross-city movements before and after holidays. Parameter fitting of gravity models reveals that travels in different type of days consider the attractiveness of destinations and cost of distance differently. Surprisingly, the comparison indicates that the parameter-free opportunity priority selection (OPS) model outperforms other models and is the best to characterize human mobility in China across all six different types of days. However, there is still an urgent need for development of more dedicated models for human mobility on weekends and different types of holidays.

2019 ◽  
Vol 38 (2) ◽  
pp. 406-416 ◽  
Author(s):  
Marcel Mikeska ◽  
Jan Najser ◽  
Václav Peer ◽  
Jaroslav Frantík ◽  
Jan Kielar

Gas from the gasification of pellets made from renewable sources of energy or from lower-quality fuels often contains a number of pollutants. This may cause technical difficulties during the gas use in internal combustion gas engines used for energy and heat cogeneration. Therefore, an adequate system of gas cleaning must be selected. In line with such requirements, this paper focuses on the characterization and comparison of gases produced from different types of biomass during gasification. The biomass tested was wood, straw, and hay pellets. The paper gives a detailed description and evaluation of the measurements from a fix-bed gasifier for the properties of the produced gases, raw fuels, tar composition, and its particle content before and after the cleaning process. The results of elemental composition, net calorific value, moisture, and ash content show that the cleaned gases are suitable for internal combustion engine-based cogeneration systems, but unsuitable for gas turbines, where a different cleaning technology would be needed.


Electronics ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 33
Author(s):  
Enrique Hernández-Orallo ◽  
Antonio Armero-Martínez

One of the key factors for the spreading of human infections, such as the COVID-19, is human mobility. There is a huge background of human mobility models developed with the aim of evaluating the performance of mobile computer networks, such as cellular networks, opportunistic networks, etc. In this paper, we propose the use of these models for evaluating the temporal and spatial risk of transmission of the COVID-19 disease. First, we study both pure synthetic model and simulated models based on pedestrian simulators, generated for real urban scenarios such as a square and a subway station. In order to evaluate the risk, two different risks of exposure are defined. The results show that we can obtain not only the temporal risk but also a heat map with the exposure risk in the evaluated scenario. This is particularly interesting for public spaces, where health authorities could make effective risk management plans to reduce the risk of transmission.


2021 ◽  
Vol 11 (5) ◽  
pp. 590
Author(s):  
Raeghan L. Mueller ◽  
Jarrod M. Ellingson ◽  
L. Cinnamon Bidwell ◽  
Angela D. Bryan ◽  
Kent E. Hutchison

In recent years of expanding legalization, older adults have reported the largest increase in cannabis use of any age group. While its use has been studied extensively in young adults, little is known about the effects of THC in older adults and whether the risks of cannabis might be different, particularly concerning intoxication and cognition. The current study investigated whether age is associated with the deleterious effects of THC on cognitive performance and other behavioral measures before and after ad libitum self-administration of three different types of cannabis flower (THC dominant, THC + CBD, and CBD dominant). Age groups consisted of young adults (ages 21–25) and older adults (ages 55–70). Controlling for pre-use scores on all measures, the THC dominant chemovar produced a greater deleterious effect in younger adults compared with older adults in tests of learning and processing speed, whereas there were no differences between old and young in the effects of the other chemovars. In addition, the young group reported greater cannabis craving than the older group after using the THC chemovar. Consistent with some reports in the preclinical literature, the findings suggest that older adults may be less sensitive to the effects of THC on cognitive and affective measures.


Land ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 424
Author(s):  
Clara-Jane Blye ◽  
Elizabeth A. Halpenny ◽  
Glen T. Hvenegaard ◽  
Dee Patriquin

This study explores how knowledge was and is mobilized to advance the objectives of the Beaver Hills Biosphere Reserve, located in Alberta, Canada. Established in 2016, a 12-year collaborative effort worked to establish the biosphere reserve and achieve formal UNESCO designation. Subsequent efforts to grow the newly established biosphere reserve have accelerated in recent years. Our study documented how different types of knowledge were accessed, created, curated, and shared between partners during these two time periods. Focus group interviews were conducted with 14 participants, who are affiliated with Beaver Hills Biosphere Reserve partner organizations, and revealed the following findings: (1) not all knowledge is equally valued or understood; (2) partnerships are highly valued, and were essential to successful knowledge mobilization, but were stronger among individuals rather than organizations; (3) fear of the loss of autonomy and potential complications due to the establishment of a biosphere reserve slowed the exchange of information and engagement by some regional actors; and (4) knowledge mobilization is and was impeded by staff and agency capacity, finances, and time scarcity. This was further complicated by entrenched norms of practice, existing successful working relationships impeding the development of new partnerships, and embracing alternative forms of knowledge.


2021 ◽  
pp. 002224372110560
Author(s):  
Omid Rafieian ◽  
Hema Yoganarasimhan

Users are often exposed to a sequence of short-lived marketing interventions (e.g., ads) within each usage session in mobile apps. This study examines how an increase in the variety of ads shown in a session affects a user's response to the next ad. The authors leverage the quasi-experimental variation in ad assignment in their data and propose an empirical framework that accounts for different types confounding to isolate the effects of a unit increase in variety. Across a series of models, the authors consistently show that an increase in ad variety in a session results in a higher response rate to the next ad: holding all else fixed, a unit increase in variety of the prior sequence of ads can increase the click-through rate on the next ad by approximately 13\%. The authors then explore the underlying mechanism and document empirical evidence for an attention-based account. The paper offers important managerial implications since it identifies a source of interdependence across ad exposures that is often ignored in the design of advertising auctions. Further, the attention-based mechanism suggests that platforms can incorporate real-time attention measures to help advertisers with targeting dynamics.


Author(s):  
Peter McCormick

AbstractGiven the visibility and obvious importance of judicial power in the age of the Charter, it is important to develop the conceptual vocabulary for desribing and assessing this power. One such concept that has been applied to the study of appeal courts in the United States and Great Britain is “party capability”, a theory which suggests that different types of litigant will enjoy different levels of success as both appellant and respondent. Using a data base derived from the reported decisions of the provincial courts of appeal for the second and seventh year of each decade since the 1920s, this article applies party capability theory to the performance of the highest courts of the ten provinces; comparisons are attempted across regions and across time periods, as well as with the findings of similar studies of American and British courts.


2011 ◽  
Vol 4 (3) ◽  
pp. 15
Author(s):  
James A. Seifert ◽  
David E. Mielke

This study reports on the financial markets reaction to the defeasance of corporate debt and whether the market perceives a changes in risk as a result of this activity. The prices of seventeen bonds both before and after defeasance were analyzed using t-tests to determine if any significant price changes related to the act of defeasance occurred between these two time periods. Contrary to what might be expected no significant differences were found.


2021 ◽  
pp. 51-61
Author(s):  
A. Yu. Vasil'ev ◽  
V. V. Petrovskaya ◽  
E. A. Nichipor ◽  
V. G. Alpatova ◽  
N. N. Potrakhov ◽  
...  

During the course of this experimental study tomograms of extracted teeth were analyzed before and after filling the root canals with an endodontic material and fragments of broken metal instruments for root canal treatment. During the first stage of the experiment, untreated extracted teeth were scanned using conebeam computed tomography and microfocus cone-beam computed tomography. A comparative assessment of capabilities of the two methods of cone-beam computed tomography based on examination of untreated root canals was carried out. The second part of the study is dedicated to visualization of root canals that contain foreign high-density materials.


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