Human mobility synthesis using matrix and tensor factorizations

Human mobility prediction is of great advantage in route planning and schedule management. However, mobility data is a high-dimensional dataset in which multi-context prediction is difficult in a single model. Mobility data can usually be expressed as a home event, a work event, a shopping event and a traveling event. Previous works have only been able to learn and predict one type of mobility event and then integrate them. As the tensor model has a strong ability to describe high-dimensional information, we propose an algorithm to predict human mobility in tensors of location context data. Using the tensor decomposition method, we extract human mobility patterns with multiple expressions and then synthesize the future mobility event based on mobility patterns. The experiment is based on real-world location data and the results show that the tensor decomposition method has the highest accuracy in terms of prediction error among the three methods. The results also prove the feasibility of our multi-context prediction model.     

Impact of vehicle charging on Portugal's national electricity load profile in 2030

This study aims to explore the impact of light-duty passenger (LdP) electric vehicle (EV) charging on the Portuguese national load profile (LP) in 2030. The goal is to identify EV charging strategies that enable a sustainable configuration of the Portuguese LP under different potential levels of LdP EV penetration in 2030. The research offers Portuguese utilities and policymakers information regarding potential threats and solutions of different EV charging strategies on the national grid infrastructure in 2030. Furthermore, it proposes a methodology that can also be adopted in other countries to analyse similar problems. Low, medium, and high penetration scenarios were designated based on the number of LdP EVs. The low and medium penetration scenarios indicate that an intelligent grid is not necessary to perform charging activities. However, coordinating EV charging in the evening via a smart grid (SG) is imperative in the high penetration scenario, as unsustainable levels of power demand will otherwise be reached, compared with the current production and distribution capacity. Moreover, morning charging sessions must also be addressed, as they may induce new peaks of daily consumption given the significant amount of charging activity taking place within that period.     

空间的叙事--对张应鹏无锡南洋学院的一种阅读

空间不是一种苍白的存在,它直指建筑的生命意识;空间不是设计者的附庸,它以独立的思想与情感讲诉自己的故事。这种叙事是开放的,任何空间的参与者可以融入自己的话语,进行自己的解码与编排;这种叙事是流动的,无休无止,没有确切的来龙去脉;这种叙事是透明的,活动于空间内的人和物永远是真实的展露;这种叙事是感性的,只有善感的心灵才能感知它的存在。     

Job Search Networks and Strategies in Scattered-site Public Housing

How does poverty dispersal influence the job search tactics and networks of poor women? Using the results of interviews with 253 women living in dispersed and small clusters of public housing, this paper examines how job networks and search tactics may vary. The premise is that the mechanisms involved in connecting poor residents of more affluent areas with opportunity may consist of both social connections and new strategies for accessing opportunity. The paper finds that dispersed residents have job networks containing more diverse information. Second, dispersed residents more often used formal methods to find their most recent job. Third, dispersed residents seek better jobs, net of demographic controls, search method, and search outcome. The paper discusses the implications of these findings for the design of housing mobility and mixed-income housing programmes, the current policy emphasis at the US Department of Housing and Urban Development.     

Sub-micrometer particulate air pollution and cardiovascular mortality in Beijing, China

Background

While the link between particulate matter and cardiovascular mortality is well established, it is not fully investigated and understood which properties of the aerosol might be responsible for the health effects, especially in polluted mega-city areas.

Objectives

Our goal was to explore the association between daily cardiovascular mortality and different particle metrics in the sub-micrometer range in Beijing, China.

Methods

We obtained daily counts of cause-specific cardiovascular deaths in the Beijing urban area for the period March 2004 to August 2005. Concurrently, continuous measurements of particle number size distributions were performed. Particle number concentrations (NC) between 0.003 μm and 0.8 μm were converted to particle mass and surface area concentrations assuming spherical particles. Semi-parametric Poisson regression models adjusting for trend, seasonality, day of the week, and meteorology were used to estimate immediate, delayed and cumulative particle effects. Additionally, effect modification by air mass origin was investigated.

Results

We observed associations between daily cardiovascular mortality and particle NC for a 2-days delay. Moreover, nearly all particle metrics showed 2-days delayed associations with ischemic heart disease mortality. The strongest association was found for particle NC in the size range 0.03-0.1 μm (7.1% increase in daily mortality with a 95%-confidence interval of 2.9%-11.5%, per an increase of 6250 particles/cm³). Results for surface and mass concentrations with a lag of two days indicated effect modification by air mass origin, whereas effects of particle NC were not modified.

Conclusions

Results show an elevated risk of cardiovascular mortality in Beijing from short-term exposure to particulate air pollution in the sub-micrometer range. Results also indicate that locally produced smaller particles and regionally transported particles may exhibit different effects in Beijing.     

缝合城市机动性与可持续发展的裂痕——中欧大学联合城市规划设计竞赛之回顾

现代城市的发展很大程度上依赖高效运转的城市交通系统。城市交通的改善的确给我们带来了便利，促进了地区的发展，但大型城市变通设施割裂了城市的肌理，湮灭了城市的特性，我们的城市正在变成一堆堆构筑物的集合体，滚滚车流在带来商机的同时也带来了日益严重的环境问题，导致城市品质的退化。如何保持机动性与可持续发展之间的协调是我国城市普遍面临的巨大挑战，这既需要先进的理念，更需要不同专业知识、不同文化背景的专业人员的其同探讨。以“城市机动性和可持续发展”为主题由中欧四国六所大学联合举行的的城市规划设计竞赛，标志着一种全新的探讨。我们相信法国动态城市基金会的一系列学术活动必将会影响到城市交通规划的价值取向。     

Safe mobility for elderly drivers—Considerations based on expert and self-assessment

To further understand the needs of the growing population of elderly drivers and create solutions for safe mobility it is important to understand the driving scenarios and aspects in day to day traffic that may be of challenge for this group. More so, individual differences in how drivers perceive their own driving ability may have an effect on how individuals limit their mobility and/or increase their exposure to risk situations, with a potential negative effect on safety.     

Solution-processed high-performance photodetector based on a new triisopropylsilylethynyl anthracene derivative

A new triisopropylsilylethynyl anthracene derivative was synthesized with extended aromatic groups at the 2- and 6-positions of anthracene for application in a high-performance photodetector. To optimize charge transport characteristics and photodetection ability, single crystal with high aspect ratio was employed as photo-active semiconductor layer. When operated at room temperature under ambient conditions, the photodetector based on a single crystal showed a sensitive response to green light, with a responsivity >10 A/W and specific detectivity on the order of 10¹¹ Jones. Based on a systematic analysis of the photocurrent behavior as a function of the interfacial properties, illuminated optical power and the applied bias, the operating mechanism of the photodetector was found to be a gain-generation process.     

Photophysical and charge-transporting properties of the copolymer SuperYellow

Conjugated copolymers are important materials for organic light-emitting diodes. Here, an investigation of the photophysical and charge-transporting properties of the prototypical poly(p-phenylene vinylene) based copolymer SuperYellow (SY) is reported. The study also investigated the effect of processing conditions by comparing the properties of spin-coated and solution-cast films. For both types of films, the results of time-resolved fluorescence and photoluminescence quantum yield measurements are similar. The high photoluminescence quantum yield of 60% and its independence of processing conditions shows the effectiveness of the bulky side groups in preventing concentration quenching of fluorescence. Time of flight measurements of charge mobility in both spin-coated and solution-cast films also showed similar results, with mobilities in the range 10^?6–10^?7 cm²/V s for both films. These results provide important information about a widely used copolymer and show that a good polymer light-emitting diode material can have low mobility.