The ever-increasing number of automobiles, especially private cars, has irrevocably altered social life, revolutionized travel experience, and reshaped the face of urban transportation systems. ...Existing research mainly focuses on trajectory data from floating cars, while human mobility and travel behavior by private cars are still little understood. To bridge this gap, we employ a private car trajectory data set collected from real-world urban environments. This article provides a new perspective on human mobility, with a focus on private cars, by investigating mobility patterns and capturing the spatiotemporal evolution of urban hot zones from people's arrive-stay-leave (ASL) behavior. Understanding these hot zones and travel behavior patterns is necessary when considering changes or improvements in urban networks. Decisions impacting the safety and emissions impacts of urban travel, including, for example, design improvements at curves or to reduce left-turn conflicts, improvements to pedestrian facilities, and the placement of alternative energy refueling stations, will rely on similar analyses across many different urban areas. Our article provides a proof of concept, and we then outline new research opportunities and challenges involving private car trajectory data.Along with the increased process of urbanization and industrialization, recent years have witnessed an ever-increasing number of automobiles, especially private cars <xref ref-type="bibr" rid="ref1">1 , also known as passenger cars , those with less than seven seats and usually registered to individuals for personal use. Compared to floating cars <xref ref-type="bibr" rid="ref2">2 , private cars constitute the vast majority of automobiles. For instance, the nationwide ownership of automobiles in China exceeded 263 million by the end of 2019 <xref ref-type="bibr" rid="ref3">3 , and more than 88% of these vehicles (225 million) were registered to individuals. As shown in <xref ref-type="fig" rid="fig1">Figure 1(a) , ownership of private cars exhibited a growing trend from 2013 to 2019. As seen in Sivak's technical report <xref ref-type="bibr" rid="ref4">4 , per capita car ownership in the United States was 0.756 in 2015 and increased to 0.766 by 2016. According to <xref ref-type="bibr" rid="ref5">5 , in the last two decades, private cars accounted for more than 75% of passenger transport activity in the European Union. As shown in <xref ref-type="fig" rid="fig1">Figure 1(b) , even though a slightly decreasing trend is expected by 2030, it is still expected to be larger than 72%.
Traditional student information systems were designed primarily to collect and manage records of course enrollment and credit hours earned, as well as other data elements needed to monitor each ...student's progress to graduation. Now, institutions want to monitor and improve the quality and equity of students' learning experiences in courses and the co-curriculum, especially in those experiences known as high-impact educational practices (HIPs), such as learning communities, service learning, and undergraduate research. Since the framework of traditional student information systems was not created with these data needs in mind, existing institutional data are often inadequate to effectively examine questions around HIPs on a campus. This article describes how institutions can engage in this work as they connect high-impact educational practices to student outcomes, both in and beyond traditional courses. The authors' goal is to redefine the data GIGO: great-in leads to great-out.
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484.
ACCESS Magazine Spring 2002 Chen, Chao; De Valois, Karen; Disch, Michael ...
IDEAS Working Paper Series from RePEc,
01/2002
Paper
We report new HST and ground-based observations of a damped Lyman-alpha
absorption system toward the QSO 0850+4400. The redshift of the absorption
system is z = 0.163770 and the neutral hydrogen ...column density of the
absorption system is log N = 19.81 cm**-2. The absorption system is by far the
lowest redshift confirmed damped Lyman-alpha absorption system yet identified,
which provides an unprecedented opportunity to examine the nature, impact
geometry, and kinematics of the absorbing galaxy in great detail. The
observations indicate that the absorption system is remarkable in three
respects: First, the absorption system is characterized by weak metal
absorption lines and a low metal abundance, possibly less than 4% of the solar
metal abundance. This cannot be explained as a consequence of dust, because the
neutral hydrogen column density of the absorption system is far too low for
obscuration by dust to introduce any significant selection effects. Second, the
absorption system is associated with a moderate-luminosity early-type S0
galaxy, although the absorption may actually arise in one of several very faint
galaxies detected very close to the QSO line of sight. Third, the absorbing
material moves counter to the rotating galaxy disk, which rules out the
possibility that the absorption arises in a thin or thick co-rotating gaseous
disk. These results run contrary to the expectation that low-redshift damped
Lyman-alpha absorption systems generally arise in the gas- and metal-rich inner
parts of late-type spiral galaxies. We suggest instead that mounting evidence
indicates that low-redshift galaxies of a variety of morphological types may
contain significant quantities of low metal abundance gas at large
galactocentric distances.
We report new HST and ground-based observations of a damped Lyman-alpha absorption system toward the QSO 0850+4400. The redshift of the absorption system is z = 0.163770 and the neutral hydrogen ...column density of the absorption system is log N = 19.81 cm**-2. The absorption system is by far the lowest redshift confirmed damped Lyman-alpha absorption system yet identified, which provides an unprecedented opportunity to examine the nature, impact geometry, and kinematics of the absorbing galaxy in great detail. The observations indicate that the absorption system is remarkable in three respects: First, the absorption system is characterized by weak metal absorption lines and a low metal abundance, possibly less than 4% of the solar metal abundance. This cannot be explained as a consequence of dust, because the neutral hydrogen column density of the absorption system is far too low for obscuration by dust to introduce any significant selection effects. Second, the absorption system is associated with a moderate-luminosity early-type S0 galaxy, although the absorption may actually arise in one of several very faint galaxies detected very close to the QSO line of sight. Third, the absorbing material moves counter to the rotating galaxy disk, which rules out the possibility that the absorption arises in a thin or thick co-rotating gaseous disk. These results run contrary to the expectation that low-redshift damped Lyman-alpha absorption systems generally arise in the gas- and metal-rich inner parts of late-type spiral galaxies. We suggest instead that mounting evidence indicates that low-redshift galaxies of a variety of morphological types may contain significant quantities of low metal abundance gas at large galactocentric distances.
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