Urban nighttime leisure space mapping with nighttime light images and POI data

Urban nighttime leisure spaces (UNLSs), important urban sites of nighttime economic activity, have created enormous economic and social benefits. Both the physical features (e.g., location, shape, and area) and the social functions (e.g., commercial streets, office buildings, and entertainment venues) of UNLSs are important in UNLS mapping. However, most studies rely solely on census data or nighttime light (NTL) images to map the physical features of UNLSs, which limits UNLS mapping, and few studies perform UNLS mapping from a social function perspective. Point-of-interest (POI) data, which can reflect social activity functions, are needed. As a result, a novel methodological UNLS mapping framework, that integrates NTL images and POI data is required. Consequently, we first extracted high-NTL intensity and high-POI density areas from composite data as areas with high nightlife activity levels. Then, the POI data were analyzed to identify the social functions of leisure spaces revealing that nighttime leisure activities are not abundant in Beijing overall, the total UNLS area in Beijing is 31.08 km(2), which accounts for only 0.2% of the total area of Beijing. In addition, the nightlife activities in the central urban area are more abundant than those in the suburbs. The main urban area has the largest UNLS area. Compared with the nightlife landmarks in Beijing established by the government, our results provide more details on the spatial pattern of nighttime leisure activities throughout the city. Our study aims to provide new insights into how multisource data can be leveraged for UNLS mapping to enable researchers to broaden their study scope. This investigation can also help government departments better understand the local nightlife situation to rationally formulate planning and adjustment measures

Chiral-Phosphoramide-Catalyzed Enantioselective Allylation Reactions: Mechanistic, Structural and Preparative Studies

403 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2003.The method of generating chiral Lewis acids with a combination of SiCl 4 and chiral phosphoramides has been applied in the formal hetero-Diels-Alder reaction and modest to high selectivities have been obtained.U of I OnlyRestricted to the U of I community idenfinitely during batch ingest of legacy ETD

Chiral-Phosphoramide-Catalyzed Enantioselective Allylation Reactions: Mechanistic, Structural and Preparative Studies

403 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2003.The method of generating chiral Lewis acids with a combination of SiCl 4 and chiral phosphoramides has been applied in the formal hetero-Diels-Alder reaction and modest to high selectivities have been obtained.U of I OnlyRestricted to the U of I community idenfinitely during batch ingest of legacy ETD

Development of a Cyclosporin derivative and of its synthesis as cyclophilin inhibitor with excellent anti-HCV potency

Synthetic modification of cyclosporine A at P3-P4 positions led to the discovery of NIM258, a next generation cyclophilin inhibitor with excellent anti-HCV potency, decreased transporter inhibition and pharmacokinetics suitable for coadministration with other drugs. Herein, we disclosed the evolution of the synthetic strategy to NIM258 from the original medicinal chemistry route, designed for late diversification, to a convergent and robust development synthesis. The chiral centers in P4 fragment was constructed by an asymmetric chelated Claisen rearrangement in the presence of quinidine as chiral ligand. Identification of advanced cyrstalline intermediates enabled practical supply of advanced compounds. Finally, the macrocyclization was carried out at 10% weight concentration by an unprecedented “slow release” concept

Long-Term Trends and Variability of Hydroclimate Variables and Their Linkages with Climate Indices in the Songhua River

The long-term trends and variability of hydroclimate variables are critical for water resource management, as well as adaptation to climate change. Three popular methods were used in this study to explore the trends and variability of hydroclimate variables during last 122 years in the Songhua River (SHR), one of most important river systems in China. Results show the followings: (1) There was an obvious pattern of decadal oscillations, with three positive and three negative precipitation and streamflow anomalies. The lengths of these phases vary from 11 to 36 years. (2) Annual temperature demonstrated a statistically significant increasing trend in the last 122 years, and the trend magnitude was 0.30 °C/10 years in the last 50–60 years, being larger than that of the global surface temperature. It has increased much faster since 1970. (3) Monthly precipitation in the winter season in recent years was almost the same as that in earlier periods, but a significantly increasing monthly streamflow was observed due to snowmelt under a warming climate. (4) A statistically significant correlation between hydroclimate variables and climate indices can be determined. These results could be used to make better water resource management decisions in the SHR, especially under future climate change scenarios

Distance-Based Congestion Pricing with Day-to-Day Dynamic Traffic Flow Evolution Process

This paper studies the distance-based congestion pricing in a network considering the day-to-day dynamic traffic flow evolution process. It is well known that, after an implementation or adjustment of a new congestion toll scheme, the network environment will change and traffic flows will be nonequilibrium in the following days; thus it is not suitable to take the equilibrium-based indexes as the objective of the congestion toll. In the context of nonequilibrium state, prior research proposed a mini–max regret model to solve the distance-based congestion pricing problem in a network considering day-to-day dynamics. However, it is computationally demanding due to the calculation of minimal total travel cost for each day among the whole planning horizon. Therefore, in order to overcome the expensive computational burden problem and make the robust toll scheme more practical, we propose a new robust optimization model in this paper. The essence of this model, which is an extension of our prior work, is to optimize the worst condition among the whole planning period and ameliorate severe traffic congestions in some bad days. Firstly, a piecewise linear function is adopted to formulate the nonlinear distance toll, which can be encapsulated to a day-to-day dynamics context. A very clear and concise model named logit-type Markov adaptive learning model is then proposed to depict commuters’ day-to-day route choice behaviors. Finally, a robust optimization model which minimizes the maximum total travel cost among the whole planning horizon is formulated and a modified artificial bee colony algorithm is developed for the robust optimization model