Examples of noncommutative manifolds: complex tori and spherical manifolds

We survey some aspects of the theory of noncommutative manifolds focusing on the noncommutative analogs of two-dimensional tori and low-dimensional spheres. We are particularly interested in those aspects of the theory that link the differential geometry and the algebraic geometry of these spaces.Comment: Survey article. Final version. To appear in the proceedings volume of the "International Workshop on Noncommutative Geometry", IPM, Tehran 200

Traffic Congestion and Infant Health: Evidence from E-ZPass

We exploit the introduction of electronic toll collection, (E-ZPass), which greatly reduced both traffic congestion and vehicle emissions near highway toll plazas. We show that the introduction of E-ZPass reduced prematurity and low birth weight among mothers within 2km of a toll plaza by 10.8% and 11.8% respectively relative to mothers 2-10km from a toll plaza. There were no immediate changes in the characteristics of mothers or in housing prices near toll plazas that could explain these changes. The results are robust to many changes in specification and suggest that traffic congestion contributes significantly to poor health among infants.

The Use of Public Plazas in China and the United States: Measuring the Differences Using Direct Observation in Boston and Chongqing

China’s development during the last several decades has happened at an amazing speed, and public plazas in China have changed considerably. For example, public dancing has become a very popular activity in most public plazas, and many more people than before are using these new plazas. However, some plazas are less popular than others. Therefore it is important to know what are the elements that affect people’s use of China’s public plazas? In the United States, William H. Whyte’s research proposed seven elements in public space that affect people. This study tried to answer the following questions: 1) Do William H. Whyte’s seven elements also apply to China? 2) How are urban public plazas used differently in the United States and China

Granger causality analysis on PLUS highway traffic network

PLUS Malaysia Berhad (PMB) is the largest toll expressway operator in Malaysia and South East Asia. Based on this reputation, PLUS handled thousands of vehicles every day. It covers the in-coming and out-coming traffic burdens from the northern areas to the southern areas. In order to manage these traffic burdens, toll plazas are located along this highway. Previous studies revealed that some of these toll plazas are important in managing the traffic burdens. This study analyze the importance of Skudai (SKD) toll plaza in Johor from 2009 until 2013. The causal relationship between SKD toll plaza with other toll plazas in Johor is studied to determine if there is any potential correlation or relationship of SKD with other toll plazas by using the Granger causality analysis. The findings show that there is a bidirectional Granger causality between SKD and Tangkak (TGK) as well as Machap (MAC) toll plazas. Meanwhile, there is only a unidirectional Granger causality between SKD and Yong Peng Utara (YPU) and Yong Peng Selatan (YPS) toll plazas. These results benefit the PLUS highway management to identify which potential toll plazas that can increase the traffic burden out from SKD toll plaza

Microscopic Simulation On The Operation And Capacity Of Toll Plaza In Malaysia

Microscopic traffic simulation software has several applications, such as performance evaluation, plan improvements, traffic operation control, design, and transportation facility management. This study presents the application of the well-known traffic simulation software VISSIM in the operation of toll plazas in Malaysia. This study evaluates the overall toll operation of two types of closed system toll plazas in the Malaysian expressway to gain insight into the variables that influence toll operations, which in turn affect the actual capacity of toll plazas in terms of average and maximum queue length. VISSIM was used to build toll plaza models for the mainline and ramp toll plazas which are Juru and Jawi respectively, to study their toll operations and actual capacities. In order to simulate the toll operations at toll plazas, microscopic data were obtained for each vehicle arriving and departing the toll plazas through video recordings. Video recordings were taken from two sources. The first source was from the installed CCTV and the second source was from the PLUS CCTV cameras at the tollbooths. The collected field data of the Juru and Jawi toll plazas differed in terms of number of lanes, lane configuration, toll base fee, expressway location, traffic demand, and traffic composition characteristics. The toll plaza models were then calibrated according to the measure of effectiveness and key parameter to match real world toll operations at toll plazas. Results revealed that service time is the most important parameter for evaluating the toll operation of toll plazas. Moreover, service time for entry is much lower than the service time for exit. The findings indicated that the percentage of heavy vehicles in traffic flow has a significant impact on the queue lengths at the Juru and Jawi toll plazas. Apart from that, the models were used to predict the operation of toll plazas in the future upon implementation of full electronic toll collection (ETC). The results indicated that the implementation of full ETC at the entry of both the Juru and Jawi toll plazas did not improve the operations of the toll plazas. However, the implementation of full ETC at the exit significantly improved the toll operations. But, the implementation of full ETC at the exit of the Jawi toll plaza has negatively influenced the queue lengths of Touch 'n Go and Smart TAG lanes due to the location of the signalised intersection which is near to Jawi toll plaza. The study has managed to contribute to two major findings at the traffic operations at toll plaza. The first contribution is on the prediction of traffic operation at the toll plaza in the future after the implementation of full electronic toll collection system at conventional toll plazas. The second contribution is on the estimation of the actual capacity of the conventional toll plazas

In partnership? pedestrian plazas in New York City

Traditional public spaces —such as public parks, streets, and public squares—have long been part of the urban landscape. In today’s congested cities, however, creating such public spaces is difficult because they require capital investment, vacant land, and ongoing maintenance. Possibly in response to these obstacles, new types of urban public spaces have emerged. Pedestrian plazas, one of these new types, is the topic of this research, with a focus on the New York City Plaza Program, which was the first such program in the U.S. For this research, the design, management, and use characteristics of five completed pedestrian plazas were examined, with attention also given to the partnerships behind the creation and maintenance of these plazas. The role the partners played in the plaza program was also investigated to understand its impact on the design, management, maintenance, and use of pedestrian plazas. The five case study plazas are located in neighborhoods without sufficient public space, as determined by the Department of Transportation, which runs the program. The following data collection strategies were used: site observations, user surveys, and interviews with government officials and sponsor partners. This research demonstrates that although pedestrian plazas are relatively small and are located immediately adjacent to roadways, they fulfill an important role in urban neighborhoods that otherwise lack sufficient public space for recreation. The type and diversity of activities vary between the plazas, depending on features of their design, maintenance, and management. The findings suggest that partnerships between the City and community organizations in the New York City Plaza Program play a prominent role in shaping design, maintenance, and management strategies, which affect their use. Neighborhood residents use the case study pedestrian plazas in a variety of ways, including for gathering with friends and family, people-watching, chatting, eating and drinking, and attending programmed events. Some plazas are typically frequented by the same people on a daily basis and become popular gathering places whereas other plazas are more often used for shorter periods of time for eating lunch, meeting someone, and taking a brief rest

Examining the Relationship Between Key Visual Characteristics of Urban Plazas and Aesthetic Response

This is the Published Version made available with the permission of the publisher.Urban plazas as public spaces occur in every town and city around the world; however, some plazas are more user-friendly and successful than others. This study examined that “aesthetics” also have a significant impact to determine the extent of success of urban plazas and urban open spaces in combination with other quantitative factors, such as centrality of location, provision of services, and amenities. In addition, this research sought to focus on the relationship between visual characteristics and aesthetic response to urban plazas. Photo elicitation and focus interviews were conducted to identify key visual characteristics as well as to examine aesthetic responses to those characteristics. Eight plazas and designed urban open spaces in Dhaka, Bangladesh, featured in the main study, and research methods included a structured questionnaire to collect data and used semantic differential rating scales as a measuring instrument. Outcomes from this research indicate that a positive aesthetic response was linked to specific visual characteristics of urban plazas, suggesting that this information could be used to more effectively refurbish existing and design new urban plazas as public spaces.The author(s) received financial support from Endeavor Postgraduate Award (EPA), an Australian Government Funding for the research

Planning for safety in public spaces : efforts and outcomes regarding the use, perceptions, and safety of women in plazas in Viña del Mar, Chile

Although many studies have been conducted on public spaces, safety, and gender worldwide, little has been published on Latin America, much less Viña del Mar, Chile. Additionally, the plaza has played a central role in Latin American societies for centuries, yet few contemporary studies exist. This work examines the use and perceptions of plazas and safety in two main plazas in Viña del Mar: Plaza Vergara and Plaza O’Higgins. I uncover the feelings, motivations, and perceptions underpinning the uses manifested in these plazas with a focus on the differences between men and women. Fear of violence is a common theme among women and is manifested in the ways in which women use plazas, particularly as compared to men. In addition to gaining a fuller understanding of the social life of plazas, my study synthesizes recommendations expressed by female residents of Viña del Mar for improving plazas and other public spaces. My hope is that this study will encourage greater consideration of gender when planning public spaces in Viña del Mar and beyond.Community and Regional Plannin