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Commercial microwave link (MWL) used by mobile telecom operators for data transmission can provide hydro-meteorologically valid rainfall estimates according to studies in the past decade. For the first time, this study investigated a new method, the MSG technique, that uses Meteosat Second Generation (MSG) satellite data to improve MWL rainfall estimates. The investigation, conducted during daytime, used MSG optical (VIS0.6) and near IR (NIR1.6) data to estimate rain areas along a 15 GHz, 9.88 km MWL for classifying the MWL signal into wet–dry periods and estimate the baseline level. Additionally, the MSG technique estimated a new parameter, wet path length, representing the length of the MWL that was wet during wet periods. Finally, MWL rainfall intensity estimates from this new MSG and conventional techniques were compared to rain gauge estimates. The results show that the MSG technique is robust and can estimate gauge comparable rainfall estimates. The evaluation scores every three hours of RMSD, relative bias, and r2 based on the entire evaluation period results of the MSG technique were 2.61 mm h−1, 0.47, and 0.81, compared to 2.09 mm h−1, 0.04, and 0.84 of the conventional technique, respectively. For convective rain events with high intensity spatially varying rainfall, the results show that the MSG technique may approximate the actual mean rainfall estimates better than the conventional technique.
Kingsley K. Kumah; Joost C. B. Hoedjes; Noam David; Ben H. P. Maathuis; H. Oliver Gao; Bob Z. Su. The MSG Technique: Improving Commercial Microwave Link Rainfall Intensity by Using Rain Area Detection from Meteosat Second Generation. Remote Sensing 2021, 13, 3274 .
AMA StyleKingsley K. Kumah, Joost C. B. Hoedjes, Noam David, Ben H. P. Maathuis, H. Oliver Gao, Bob Z. Su. The MSG Technique: Improving Commercial Microwave Link Rainfall Intensity by Using Rain Area Detection from Meteosat Second Generation. Remote Sensing. 2021; 13 (16):3274.
Chicago/Turabian StyleKingsley K. Kumah; Joost C. B. Hoedjes; Noam David; Ben H. P. Maathuis; H. Oliver Gao; Bob Z. Su. 2021. "The MSG Technique: Improving Commercial Microwave Link Rainfall Intensity by Using Rain Area Detection from Meteosat Second Generation." Remote Sensing 13, no. 16: 3274.
The purpose of this study is to define a holistic and effective architectural approach for implementing a safe and profitable pilot UAM airport shuttling system, which is extensible to the best available data at a given time. The proposition of this research is to leverage a system of autonomous UAVs capable of vertical takeoff and landing (VTOL) to transport passengers and cargo between airports and defined destinations in different urban cities in the United States: Atlanta, Los Angeles, and Dallas. The study comprises of defining a standard set of metrics to consider, developing a system model for defined case studies, and performing tradespace analyses to quantifiably evaluate alternative ways of achieving the most desirable architecture outcomes. This study models and evaluates 1,620 enumerable architectures and analyzes numerous tradespaces to examine the correlation and interrelationships between decision variables and performance metrics. Among the metrics, this analysis focuses on the interrelationships between Annual Profit, Mean Time Between Incident (MTBI), Upfront Cost, and Passengers Shuttled Per Day. The resulting analysis ranks architectures on the True and Fuzzy Pareto Front that is used to determine essential and quasi-necessary features in relation to these interrelationships. Based on the various stakeholders and their unique needs, the model recommends Los Angeles as the pilot city and for the system to leverage a FIFO queuing system, a smartphone interface, and a hybrid energy source that utilizes electric energy.
Emily Lewis; Jesse Ponnock; Qamar Cherqaoui; Scott Holmdahl; YuS Johnson; Alfred Wong; H. Oliver Gao. Architecting urban air mobility airport shuttling systems with case studies: Atlanta, Los Angeles, and Dallas. Transportation Research Part A: Policy and Practice 2021, 150, 423 -444.
AMA StyleEmily Lewis, Jesse Ponnock, Qamar Cherqaoui, Scott Holmdahl, YuS Johnson, Alfred Wong, H. Oliver Gao. Architecting urban air mobility airport shuttling systems with case studies: Atlanta, Los Angeles, and Dallas. Transportation Research Part A: Policy and Practice. 2021; 150 ():423-444.
Chicago/Turabian StyleEmily Lewis; Jesse Ponnock; Qamar Cherqaoui; Scott Holmdahl; YuS Johnson; Alfred Wong; H. Oliver Gao. 2021. "Architecting urban air mobility airport shuttling systems with case studies: Atlanta, Los Angeles, and Dallas." Transportation Research Part A: Policy and Practice 150, no. : 423-444.
Vehicle electrification, automation, and shared mobility – also referred to as the transportation three revolutions (3Rs) – are the emerging trends in future mobility. This study performed a comprehensive integrated analysis to investigate the potential future development of passenger transportation in the United States. A technical-economic mobility model, a chemical transport model, and a health impact assessment tool were utilized. This study first adopted several assumptions for vehicle sales under the impact of the 3Rs, and made projections to 2050 for vehicle stocks, distance travel, energy use, and carbon dioxide (CO2) emissions. This study then quantified the impacts of changing emissions on concentrations of fine particulate matter and associated health benefits. Compared to a projected 2050 business-as-usual case, the wide use of electrification could lead to reductions of ~50% in petroleum consumption and ~75% in CO2 emissions, and obtain health benefits of 5500 prevented premature deaths, corresponding to $58 billion annually. The net energy impacts of automation are highly uncertain, and the improved efficiency from automation might be offset by an increase in travel. Sharing would bring additional benefits. The combination of the 3Rs could maximize the energy savings, carbon mitigations, and health benefits. The results of this study suggest that policies/incentives are needed to promote the transition from single-occupied conventional vehicles to shared electric vehicles.
Shuai Pan; Lewis M. Fulton; Anirban Roy; Jia Jung; Yunsoo Choi; H. Oliver Gao. Shared use of electric autonomous vehicles: Air quality and health impacts of future mobility in the United States. Renewable and Sustainable Energy Reviews 2021, 149, 111380 .
AMA StyleShuai Pan, Lewis M. Fulton, Anirban Roy, Jia Jung, Yunsoo Choi, H. Oliver Gao. Shared use of electric autonomous vehicles: Air quality and health impacts of future mobility in the United States. Renewable and Sustainable Energy Reviews. 2021; 149 ():111380.
Chicago/Turabian StyleShuai Pan; Lewis M. Fulton; Anirban Roy; Jia Jung; Yunsoo Choi; H. Oliver Gao. 2021. "Shared use of electric autonomous vehicles: Air quality and health impacts of future mobility in the United States." Renewable and Sustainable Energy Reviews 149, no. : 111380.
Ming Xu; Glen T. Daigger; Chuanwu Xi; Jianguo Liu; Jiuhui Qu; Pedro J. Alvarez; Pratim Biswas; Yongsheng Chen; Dana Dolinoy; Ying Fan; Huaizhu Oliver Gao; Jiming Hao; Hong He; Daniel M. Kammen; Maria Carmen Lemos; Fudong Liu; Nancy G. Love; Yonglong Lu; Denise L. Mauzerall; Shelie A. Miller; Zhiyun Ouyang; Jonathan T. Overpeck; Wei Peng; Anu Ramaswami; Zhiyong Ren; Aijie Wang; Brian Wu; Ye Wu; Junfeng Zhang; Chunmiao Zheng; Bing Zhu; Tong Zhu; Wei-Qiang Chen; Gang Liu; Shen Qu; Chunyan Wang; Yutao Wang; Xueying Yu; Chao Zhang; Hongliang Zhang. U.S.–China Collaboration is Vital to Global Plans for a Healthy Environment and Sustainable Development. Environmental Science & Technology 2021, 55, 9622 -9626.
AMA StyleMing Xu, Glen T. Daigger, Chuanwu Xi, Jianguo Liu, Jiuhui Qu, Pedro J. Alvarez, Pratim Biswas, Yongsheng Chen, Dana Dolinoy, Ying Fan, Huaizhu Oliver Gao, Jiming Hao, Hong He, Daniel M. Kammen, Maria Carmen Lemos, Fudong Liu, Nancy G. Love, Yonglong Lu, Denise L. Mauzerall, Shelie A. Miller, Zhiyun Ouyang, Jonathan T. Overpeck, Wei Peng, Anu Ramaswami, Zhiyong Ren, Aijie Wang, Brian Wu, Ye Wu, Junfeng Zhang, Chunmiao Zheng, Bing Zhu, Tong Zhu, Wei-Qiang Chen, Gang Liu, Shen Qu, Chunyan Wang, Yutao Wang, Xueying Yu, Chao Zhang, Hongliang Zhang. U.S.–China Collaboration is Vital to Global Plans for a Healthy Environment and Sustainable Development. Environmental Science & Technology. 2021; 55 (14):9622-9626.
Chicago/Turabian StyleMing Xu; Glen T. Daigger; Chuanwu Xi; Jianguo Liu; Jiuhui Qu; Pedro J. Alvarez; Pratim Biswas; Yongsheng Chen; Dana Dolinoy; Ying Fan; Huaizhu Oliver Gao; Jiming Hao; Hong He; Daniel M. Kammen; Maria Carmen Lemos; Fudong Liu; Nancy G. Love; Yonglong Lu; Denise L. Mauzerall; Shelie A. Miller; Zhiyun Ouyang; Jonathan T. Overpeck; Wei Peng; Anu Ramaswami; Zhiyong Ren; Aijie Wang; Brian Wu; Ye Wu; Junfeng Zhang; Chunmiao Zheng; Bing Zhu; Tong Zhu; Wei-Qiang Chen; Gang Liu; Shen Qu; Chunyan Wang; Yutao Wang; Xueying Yu; Chao Zhang; Hongliang Zhang. 2021. "U.S.–China Collaboration is Vital to Global Plans for a Healthy Environment and Sustainable Development." Environmental Science & Technology 55, no. 14: 9622-9626.
Before a car-following model can be applied in practice, it must first be validated against real data in a process known as calibration. This paper discusses the formulation of calibration as an optimization problem and compares different algorithms for its solution. The optimization consists of an arbitrary car following model, posed as either an ordinary or delay differential equation, being calibrated to an arbitrary source of trajectory data that may include lane changes. Typically, the calibration problem is solved using gradient free optimization. In this work, the gradient of the optimization problem is derived analytically using the adjoint method. The computational cost of the adjoint method does not scale with the number of model parameters, which makes it more efficient than evaluating the gradient numerically using finite differences. Numerical results are presented that show that quasi-Newton algorithms using the adjoint method are significantly faster than a genetic algorithm and also achieve slightly better accuracy of the calibrated model.
Ronan Keane; H. Oliver Gao. Fast Calibration of Car-Following Models to Trajectory Data Using the Adjoint Method. Transportation Science 2021, 55, 592 -615.
AMA StyleRonan Keane, H. Oliver Gao. Fast Calibration of Car-Following Models to Trajectory Data Using the Adjoint Method. Transportation Science. 2021; 55 (3):592-615.
Chicago/Turabian StyleRonan Keane; H. Oliver Gao. 2021. "Fast Calibration of Car-Following Models to Trajectory Data Using the Adjoint Method." Transportation Science 55, no. 3: 592-615.
Over the last two decades, prevalent technologies and Internet of Things (IoT) systems have been found to have potential for carrying out environmental monitoring. The data generated from these infrastructures are readily available and have the potential to provide massive spatial coverage. The costs involved in using these data are minimal since the records are already generated for the original uses of these systems. Commercial microwave links, which provide the underlying framework for data transfer between cellular network base stations, are one example of such a system and have been found useful for monitoring rainfall. Wireless infrastructure of this kind is deployed widely by communication providers across Africa and can thus be used as a rainfall monitoring device to complement the sparse proprietary resources that currently exist or to substitute for them where alternatives do not exist. Here we focus this approach’s potential to acquire valuable information required for agricultural needs across Africa using Kenya as an example.
Noam David; Yanyan Liu; Kingsley Kumah; Joost Hoedjes; Bob Su; H. Gao. On the Power of Microwave Communication Data to Monitor Rain for Agricultural Needs in Africa. Water 2021, 13, 730 .
AMA StyleNoam David, Yanyan Liu, Kingsley Kumah, Joost Hoedjes, Bob Su, H. Gao. On the Power of Microwave Communication Data to Monitor Rain for Agricultural Needs in Africa. Water. 2021; 13 (5):730.
Chicago/Turabian StyleNoam David; Yanyan Liu; Kingsley Kumah; Joost Hoedjes; Bob Su; H. Gao. 2021. "On the Power of Microwave Communication Data to Monitor Rain for Agricultural Needs in Africa." Water 13, no. 5: 730.
Lane changing dynamics are an important part of traffic microsimulation and are vital for modeling weaving sections and merge bottlenecks. However, there is often much more emphasis placed on car following and gap acceptance models, whereas lane changing dynamics such as tactical, cooperation, and relaxation models receive comparatively little attention. This paper develops a general relaxation model which can be applied to an arbitrary parametric or nonparametric microsimulation model. The relaxation model modifies car following dynamics after a lane change, when vehicles can be far from equilibrium. Relaxation prevents car following models from reacting too strongly to the changes in space headway caused by lane changing, leading to more accurate and realistic simulated trajectories. We also show that relaxation is necessary for correctly simulating traffic breakdown with realistic values of capacity drop.
Ronan Keane; H. Oliver Gao. A formulation of the relaxation phenomenon for lane changing dynamics in an arbitrary car following model. Transportation Research Part C: Emerging Technologies 2021, 125, 103081 .
AMA StyleRonan Keane, H. Oliver Gao. A formulation of the relaxation phenomenon for lane changing dynamics in an arbitrary car following model. Transportation Research Part C: Emerging Technologies. 2021; 125 ():103081.
Chicago/Turabian StyleRonan Keane; H. Oliver Gao. 2021. "A formulation of the relaxation phenomenon for lane changing dynamics in an arbitrary car following model." Transportation Research Part C: Emerging Technologies 125, no. : 103081.
Background: Cycling to work has been promoted as a green commute in many countries because of its reduced congestion relative to that of cars and its reduced environmental impact on air pollution. However, cyclists might be exposed to higher air pollution, causing adverse health effects. Few studies have examined the respiratory effects of traffic-related air pollution exposure during short-term cycling, especially in developing countries with heavy air pollution. The aim of this study was to assess the impact of air pollution exposure on lung function while cycling in traffic. Methods: Twenty-five healthy adults in total cycled on a specified route in each of three Chinese cities during four periods of a day. Lung function measures were collected immediately before and after cycling. Real-time particulate matter (PM) and the particle number count (PNC) for particles with different sizes were measured along each cycling route, while ambient sulfur dioxide (SO2), nitrogen dioxide (NO2), ozone (O3), and carbon monoxide (CO) levels were measured at the nearest stations. Mixed-effect models were used to estimate the impact of short-term air pollution exposure on participants’ lung function measures during cycling. Results: We found that an interquartile increase in particulate matter consisting of fine particles (PM1, aerodynamic diameter £ 1 mm; and PM2.5, aerodynamic diameter £ 2.5 mm) was associated with a significant decrease in forced vital capacity (FVC) (PM1, –5.61%, p = 0.021; PM2.5, –5.57%, p = 0.022). Interquartile increases in the 99th percentile of PNC for fine particles (aerodynamic diameter 0.3–0.4 mm) also had significant negative associations with FVC (0.3 mm, –5.13%, p = 0.041; 0.35 mm, –4.81%, p = 0.045; 0.4 mm, –4.59%, p = 0.035). We also observed significant inverse relationships between ambient CO levels and FVC (–5.78%, p = 0.015).Conclusions: Our results suggest that short-term exposure to fine particles and CO while cycling in traffic contributes to a reduction in FVC of cyclists.
Lejian He; Laijun Zhao; Yonghong Liu; Zhaowen Qiu; H. Oliver Gao. Respiratory Effects of Particulate Matter Exposure During Short-Term Cycling Among Healthy Adults in Three Chinese Cities. 2020, 1 .
AMA StyleLejian He, Laijun Zhao, Yonghong Liu, Zhaowen Qiu, H. Oliver Gao. Respiratory Effects of Particulate Matter Exposure During Short-Term Cycling Among Healthy Adults in Three Chinese Cities. . 2020; ():1.
Chicago/Turabian StyleLejian He; Laijun Zhao; Yonghong Liu; Zhaowen Qiu; H. Oliver Gao. 2020. "Respiratory Effects of Particulate Matter Exposure During Short-Term Cycling Among Healthy Adults in Three Chinese Cities." , no. : 1.
Reducing carbon emissions of food supply chains has increasingly received attention from businesses and policymakers. In order to propose sound policies aimed at lowering such emissions, policy makers favor tools that are informative in the economic and environmental dimensions simultaneously. In this study we offer a systems-based approach which is intended to do just that by developing a spatially and temporally disaggregated price equilibrium mathematical model for a food production and distribution system and applying it to the U.S. apple supply chain. We considered three emission reduction interventions: a carbon tax, a land-sparing incentive, and new emission-reduction technologies. We find that R&D which leads to storage technologies with lower carbon emission rates has the greatest potential for emission reduction. Carbon taxes also has the potential to reduce emissions, but at the cost of decreasing apple production and increasing consumer price. These results are unexpected and important, particularly since several countries are implementing carbon taxes and/or land sparing/sharing strategies.
Faisal M. Alkaabneh; Jun Lee; Miguel I. Gómez; Huaizhu Oliver Gao. A systems approach to carbon policy for fruit supply chains: Carbon tax, technology innovation, or land sparing? Science of The Total Environment 2020, 767, 144211 .
AMA StyleFaisal M. Alkaabneh, Jun Lee, Miguel I. Gómez, Huaizhu Oliver Gao. A systems approach to carbon policy for fruit supply chains: Carbon tax, technology innovation, or land sparing? Science of The Total Environment. 2020; 767 ():144211.
Chicago/Turabian StyleFaisal M. Alkaabneh; Jun Lee; Miguel I. Gómez; Huaizhu Oliver Gao. 2020. "A systems approach to carbon policy for fruit supply chains: Carbon tax, technology innovation, or land sparing?" Science of The Total Environment 767, no. : 144211.
Understanding the temporal and spatial variation of air quality (AQ) impact due to congestion pricing is important since the health and economic benefits of air quality improvements depend on the distribution of traffic-related air pollution. Aiming to improve our knowledge of the AQ impacts from congestion pricing, this study integrates a disaggregate agent-based travel demand model with a hyper-local air quality model to examine emissions, air quality, and exposure. Studying congestion pricing schemes in NYC, we find that daily single-occupancy-vehicle trips to the charging area decreases by 14.5% and 24.3% under the low and high charging schemes, respectively. Correspondingly, the PM2.5 concentration decreases by 5–25% in the Central Manhattan areas in the low-toll scenario, and by more than 10% across almost all of New York City areas in the high-toll scenario. Our results indicate non-linear relations between the adaptation of travel behavior and the resulting air quality/exposure impacts.
Mohammad Tayarani; Amirhossein Baghestani; Mahdieh Allahviranloo; H. Oliver Gao. Spatial/temporal variability in transportation emissions and air quality in NYC cordon pricing. Transportation Research Part D: Transport and Environment 2020, 89, 102620 .
AMA StyleMohammad Tayarani, Amirhossein Baghestani, Mahdieh Allahviranloo, H. Oliver Gao. Spatial/temporal variability in transportation emissions and air quality in NYC cordon pricing. Transportation Research Part D: Transport and Environment. 2020; 89 ():102620.
Chicago/Turabian StyleMohammad Tayarani; Amirhossein Baghestani; Mahdieh Allahviranloo; H. Oliver Gao. 2020. "Spatial/temporal variability in transportation emissions and air quality in NYC cordon pricing." Transportation Research Part D: Transport and Environment 89, no. : 102620.
The COVID-19 pandemic has significantly affected human health and the economy. The implementation of social distancing practices to combat the virus spread, however, has led to a notable improvement in air quality. This study compared the surface air quality monitoring data from the United States Environmental Protection Agency (U.S. EPA)’s AirNow network during the period 20 March–5 May in 2020 to those in 2015–2019 from the Air Quality System (AQS) network over the state of California. The results indicated changes in fine particulate matter (PM2.5) of −2.04 ± 1.57 μg m−3 and ozone of −3.07 ± 2.86 ppb. If the air quality improvements persist over a year, it could potentially lead to 3970–8900 prevented premature deaths annually (note: the estimates of prevented premature deaths have large uncertainties). Public transit demand showed dramatic declines (~80%). The pandemic provides an opportunity to exhibit how substantially human behavior could impact on air quality. To address both the pandemic and climate change issues, better strategies are needed to affect behavior, such as ensuring safer shared mobility, the higher adoption of telecommuting, automation in the freight sector, and cleaner energy transition.
Shuai Pan; Jia Jung; Zitian Li; Xuewei Hou; Anirban Roy; Yunsoo Choi; H. Gao. Air Quality Implications of COVID-19 in California. Sustainability 2020, 12, 7067 .
AMA StyleShuai Pan, Jia Jung, Zitian Li, Xuewei Hou, Anirban Roy, Yunsoo Choi, H. Gao. Air Quality Implications of COVID-19 in California. Sustainability. 2020; 12 (17):7067.
Chicago/Turabian StyleShuai Pan; Jia Jung; Zitian Li; Xuewei Hou; Anirban Roy; Yunsoo Choi; H. Gao. 2020. "Air Quality Implications of COVID-19 in California." Sustainability 12, no. 17: 7067.
Accurate rainfall detection and estimation are essential for many research and operational applications. Traditional rainfall detection and estimation techniques have achieved considerable success but with limitations. Thus, in this study, the relationships between the gauge (point measurement) and the microwave links (MWL) rainfall (line measurement), and the MWL to the satellite observations (area-wide measurement) are investigated for (area-wide) rainfall detection and rain rate retrieval. More precisely, we investigate if the combination of MWL with Meteosat Second Generation (MSG) satellite signals could improve rainfall detection and rainfall rate estimates. The investigated procedure includes an initial evaluation of the MWL rainfall estimates using gauge measurements, followed by a joint analysis of the rainfall estimates with the satellite signals by means of a conceptual model in which clouds with high cloud top optical thickness and large particle sizes have high rainfall probabilities and intensities. The analysis produced empirical thresholds that were used to test the capability of the MSG satellite data to detect rainfall on the MWL. The results from Kenya, during the “long rains” of 2013, 2014, and 2018 show convincing performance and reveal the potential of MWL and MSG data for area-wide rainfall detection.
Kingsley Kumah; Joost Hoedjes; Noam David; Ben Maathuis; H. Gao; Bob Su. Combining MWL and MSG SEVIRI Satellite Signals for Rainfall Detection and Estimation. Atmosphere 2020, 11, 884 .
AMA StyleKingsley Kumah, Joost Hoedjes, Noam David, Ben Maathuis, H. Gao, Bob Su. Combining MWL and MSG SEVIRI Satellite Signals for Rainfall Detection and Estimation. Atmosphere. 2020; 11 (9):884.
Chicago/Turabian StyleKingsley Kumah; Joost Hoedjes; Noam David; Ben Maathuis; H. Gao; Bob Su. 2020. "Combining MWL and MSG SEVIRI Satellite Signals for Rainfall Detection and Estimation." Atmosphere 11, no. 9: 884.
When making infrastructure policies, decision makers insufficiently consider negative consequences for the environment or health. This lack of multi-sectorial awareness in policymaking triggers poor public health outcomes. To illustrate this issue, this interdisciplinary work presents evidence for the association of road infrastructure investment (as infrastructure policy) with the incidences of deaths due to transport accidents, chronic obstructive pulmonary disease, and pneumonia using nationally aggregated data from the Organisation for Economic Co-operation and Development for 27 countries over an 18-year period (1995–2012). We conduct an explorative analysis using descriptive statistics and fixed-effects panel-data regression models that include the interaction of the policy variable with the Environmental Policy Stringency Index, which proxies the awareness of negative consequences of policies. We show that countries which never achieved a score of 3 or higher for the Environmental Policy Stringency Index had higher levels of standardized death rates. This is supported by Pearson's correlation coefficients and by the results of t-tests for deaths due to transport accidents. Following the fixed-effects analysis, we find that an increase in road infrastructure investment of 1% of gross domestic product is associated, on average, with about three additional deaths per 100,000 population due to transport accidents and about 18 fewer deaths per 100,000 population due to chronic obstructive pulmonary disease using standardized death rates. A one unit increase in the Environmental Policy Stringency Index is related to about 7 fewer deaths per 100,000 population due to chronic obstructive pulmonary diseases. Marginal effects of the interaction of road infrastructure investment and the Environmental Policy Stringency Index are significant for standardized death rates due to transport accidents and chronic obstructive pulmonary disease. Multi-sectorial awareness in infrastructure policy mediates health effects for deaths due to transport accidents and chronic obstructive pulmonary disease.
Liza Von Grafenstein; H. Oliver Gao. Infrastructure policy and public health: Evidence from OECD countries. Science of The Total Environment 2020, 750, 141157 .
AMA StyleLiza Von Grafenstein, H. Oliver Gao. Infrastructure policy and public health: Evidence from OECD countries. Science of The Total Environment. 2020; 750 ():141157.
Chicago/Turabian StyleLiza Von Grafenstein; H. Oliver Gao. 2020. "Infrastructure policy and public health: Evidence from OECD countries." Science of The Total Environment 750, no. : 141157.
The evidence linking food insecurity, poor nutrition, and increased risk of chronic health problems, combined with the high cost of health-care systems to treat food insecurity, poses significant health threats and presents challenges to the food bank system. Food bank personnel and policy makers must proactively seek new policies and practices that combat food insecurity and the diseases associated with it (diabetes and malnutrition, for instance). We develop a framework for optimizing resource allocation by food banks among the agencies they serve. Our framework explicitly considers the effectiveness and efficiency measures of the resource allocation problem faced by food banks and implicitly considers the equity performance measure. We measure effectiveness based on the nutritional value of the allocation decisions, efficiency as the utility of the agencies served, and equity as fairness in the allocation of food among those agencies. To this end, we develop a dynamic programming model where the primary decision is how much of each product to allocate/distribute. To deal with the high-dimensional state space in the dynamic program, we construct approximations to the value function that are parameterized by a small number of parameters. Computational experiments using real-world data obtained from one of the food banks in New York State, which serves about 19,000 individuals per week, demonstrate the performance of the approach. Specifically, when compared against the policy currently implemented in practice, our algorithm demonstrates a 7.73% improvement in total utility. Furthermore, when compared against the offline model, where randomness is revealed upfront, the gap between our algorithm and the offline model is less than 9.50%. On the effectiveness side, our framework demonstrates a 3.0% improvement in the nutrition of the served population.
Faisal Alkaabneh; Ali Diabat; Huaizhu Oliver Gao. A unified framework for efficient, effective, and fair resource allocation by food banks using an Approximate Dynamic Programming approach. Omega 2020, 100, 102300 .
AMA StyleFaisal Alkaabneh, Ali Diabat, Huaizhu Oliver Gao. A unified framework for efficient, effective, and fair resource allocation by food banks using an Approximate Dynamic Programming approach. Omega. 2020; 100 ():102300.
Chicago/Turabian StyleFaisal Alkaabneh; Ali Diabat; Huaizhu Oliver Gao. 2020. "A unified framework for efficient, effective, and fair resource allocation by food banks using an Approximate Dynamic Programming approach." Omega 100, no. : 102300.
Emergency response systems should respond to disasters in a timely and cost-effective manner. One of the most complicated tasks facing managers is debris management. During post-disaster operations, response teams must make road network connections between supplier nodes and demand (population) nodes in order to protect human health and safety. The effectiveness of response operations depends on positioning of relief supplies in anticipation of new clearance equipment requests at new locations, as well as with relocation of clearance equipment items to rebalance the use of items post disaster. To solve this problem, a novel dynamic post-disaster debris clearance problem is introduced—one that features non-myopic positioning of clearance equipment items based on a queuing formulation that is compatible with the maximum-weighted flow problem under incomplete information proposed by Çelik et al., (2015). By including a clearance equipment positioning strategy, we improve the strategy of the stochastic debris clearance problem, with a new framework on dynamically optimizing the post-disaster debris clearance strategy with limited observable information about the disaster-relief resources located on the road network. The proposed dynamic debris clearance approach sets out to satisfy the need for debris clearance and relief services by using the connection between the demand nodes and the supplier nodes in a case where information on the disaster region is only partially observable. An empirical study of Hurricane Harvey in the City of Houston was performed to obtain concepts into the impacts of dynamic programming model and parameters in order to supply the needed relief via a positioning strategy for clearance equipment items.
Hamid R. Sayarshad; Xinpi Du; H. Oliver Gao. Dynamic post-disaster debris clearance problem with re-positioning of clearance equipment items under partially observable information. Transportation Research Part B: Methodological 2020, 138, 352 -372.
AMA StyleHamid R. Sayarshad, Xinpi Du, H. Oliver Gao. Dynamic post-disaster debris clearance problem with re-positioning of clearance equipment items under partially observable information. Transportation Research Part B: Methodological. 2020; 138 ():352-372.
Chicago/Turabian StyleHamid R. Sayarshad; Xinpi Du; H. Oliver Gao. 2020. "Dynamic post-disaster debris clearance problem with re-positioning of clearance equipment items under partially observable information." Transportation Research Part B: Methodological 138, no. : 352-372.
We propose a novel non-myopic smart parking mechanism which aims to decrease the cruising time spent in searching for parking, with the assumption of elastic demand for both on-street parking lots and parking garages. A non-myopic atomic game is formulated to address competition for parking through assignment of vehicles to candidate parking facilities that takes into account the differences in travel times for the vehicles from their point of origin to the parking facilities and the differences in walking times for the drivers from the parking facilities to their final destination, as well as dynamic pricing, cruising times, and occupancies of the parking facilities. This study integrates a socially efficient price that accounts for the waiting times of drivers in their search for parking. We incorporate a game model into the social optimum problem by considering the competition of drivers for parking spaces where the drivers’ preferences are reflected in a collective decision such as social welfare. Using actual parking data for the city of San Francisco, we found that under our proposed dynamic parking system the average social welfare per vehicle improved by up to 54% compared to other parking strategies.
Hamid R. Sayarshad; Shahram Sattar; H. Oliver Gao. A scalable non-myopic atomic game for a smart parking mechanism. Transportation Research Part E: Logistics and Transportation Review 2020, 140, 101974 .
AMA StyleHamid R. Sayarshad, Shahram Sattar, H. Oliver Gao. A scalable non-myopic atomic game for a smart parking mechanism. Transportation Research Part E: Logistics and Transportation Review. 2020; 140 ():101974.
Chicago/Turabian StyleHamid R. Sayarshad; Shahram Sattar; H. Oliver Gao. 2020. "A scalable non-myopic atomic game for a smart parking mechanism." Transportation Research Part E: Logistics and Transportation Review 140, no. : 101974.
Traffic congestion is a major challenge in metropolitan areas due to economic and negative health impacts. Several strategies have been tested all around the globe to relieve traffic congestion and minimize transportation externalities. Congestion pricing is among the most cited strategies with the potential to manage the travel demand. This study aims to investigate potential travel behavior changes in response to cordon pricing in Manhattan, New York. Several pricing schemes with variable cordon charging fees are designed and examined using an activity-based microsimulation travel demand model. The findings demonstrate a decreasing trend in the total number of trips interacting with the central business district (CBD) as the price goes up, except for intrazonal trips. We also analyze a set of other performance measures, such as Vehicle-Hours of Delay, Vehicle-Miles Traveled, and vehicle emissions. While the results show considerable growth in transit ridership (6%), single-occupant vehicles and taxis trips destined to the CBD reduced by 30% and 40%, respectively, under the $20 pricing scheme. The aggregated value of delay for all vehicles was also reduced by 32%. Our findings suggest that cordon pricing can positively ameliorate transportation network performance and consequently, improve air quality by reducing particular matter inventory by up to 17.5%. The results might facilitate public acceptance of cordon pricing strategies for the case study of NYC. More broadly, this study provides a robust framework for decision-makers across the US for further analysis on the subject.
Amirhossein Baghestani; Mohammad Tayarani; Mahdieh Allahviranloo; H. Oliver Gao. Evaluating the Traffic and Emissions Impacts of Congestion Pricing in New York City. Sustainability 2020, 12, 3655 .
AMA StyleAmirhossein Baghestani, Mohammad Tayarani, Mahdieh Allahviranloo, H. Oliver Gao. Evaluating the Traffic and Emissions Impacts of Congestion Pricing in New York City. Sustainability. 2020; 12 (9):3655.
Chicago/Turabian StyleAmirhossein Baghestani; Mohammad Tayarani; Mahdieh Allahviranloo; H. Oliver Gao. 2020. "Evaluating the Traffic and Emissions Impacts of Congestion Pricing in New York City." Sustainability 12, no. 9: 3655.
A novel approach to dynamic switching service design based on a new queuing approximation formulation is introduced to systematically control conventional buses and enable provision of flexible on-demand mobility services. This new approach guides smart vehicles in a service area that needs last mile transit services via either traditional buses, which provide fixed-route services, or flexible-route on-demand mobility services. We also include dynamic pre-positioning of idle vehicles in anticipation of new customer arrivals, and relocation of vehicles to rebalance the use of vehicles in the system, which can have a sizable effect on energy and environmental conservation. Using a New York City transit dataset, the proposed strategy for non-myopic switching between flexible-route and fixed-route service and re-positioning of idle vehicles improves social welfare by up to 32%, while the impact of the proposed strategy on vehicle miles traveled is shown to be as high as 53% over that of the current transit service.
Hamid R. Sayarshad; H. Oliver Gao. Optimizing dynamic switching between fixed and flexible transit services with an idle-vehicle relocation strategy and reductions in emissions. Transportation Research Part A: Policy and Practice 2020, 135, 198 -214.
AMA StyleHamid R. Sayarshad, H. Oliver Gao. Optimizing dynamic switching between fixed and flexible transit services with an idle-vehicle relocation strategy and reductions in emissions. Transportation Research Part A: Policy and Practice. 2020; 135 ():198-214.
Chicago/Turabian StyleHamid R. Sayarshad; H. Oliver Gao. 2020. "Optimizing dynamic switching between fixed and flexible transit services with an idle-vehicle relocation strategy and reductions in emissions." Transportation Research Part A: Policy and Practice 135, no. : 198-214.
Electric vehicles (EVs) have a key aspect in reducing the greenhouse gas effect, maintenance, and energy expenditures of drivers. A type of integration of the electric vehicle (EV) charging infrastructure is emerging based on the premise of battery swapping. Drivers can exchange their empty batteries quickly with full batteries from any battery swapping station. The limited battery capacities of electric taxis require visiting the swapping stations during pickup and drop-off tours, which entails choosing the route more effectively to avoid customer delay. We propose the dynamic routing of electric taxis with a look-ahead policy using a Markov decision process (MDP) for assigning an electric taxi fleet to customers with the assumption of elastic demand. This is the first model that focuses on the design of a non-myopic routing of electric taxis that considers the limited battery capacity through serving customers, detours of the taxi drivers to battery swapping stations (BSS), and integration of customers delay and the system cost into a dynamic non-myopic pricing policy under the objective of maximizing social benefit. Using battery recharging locations and taxicab trip data in New York City, we showed an improvement in the average of social welfare, due to use of clean and smart taxi routes based on the proposed dynamic non-myopic routing policy by up to 8% compared to the routing problem without a look-ahead policy.
Hamid R. Sayarshad; Vahid Mahmoodian; H. Oliver Gao. Non-myopic dynamic routing of electric taxis with battery swapping stations. Sustainable Cities and Society 2020, 57, 102113 .
AMA StyleHamid R. Sayarshad, Vahid Mahmoodian, H. Oliver Gao. Non-myopic dynamic routing of electric taxis with battery swapping stations. Sustainable Cities and Society. 2020; 57 ():102113.
Chicago/Turabian StyleHamid R. Sayarshad; Vahid Mahmoodian; H. Oliver Gao. 2020. "Non-myopic dynamic routing of electric taxis with battery swapping stations." Sustainable Cities and Society 57, no. : 102113.
The advent of autonomous driving technologies has created a crucial need for upgrading conventional traffic control and lane management strategies in large cities. In this research, we design an optimal lane management strategy for corridors with a heterogeneous demand of human-driven, autonomous, and communicant autonomous vehicles (HVs, AVs, and CAVs). In a monocentric city setting, we dynamically control the inflow of the network by optimizing the size of CAV platoons in the corridors based on the instantaneous condition of the integrated system. These corridors can potentially have three types of lanes for vehicles with different levels of automation technology. We model the multiple lane type corridors as sets of parallel bottlenecks with general distributions of multiclass demand. The dynamics of the congestion in the network is also modeled using the macroscopic network fundamental diagram (MNFD). To study the impacts of the rise in the penetration rate of AVs and CAVs on the performance of the system, we derive a closed-form representation of the model. We show that the increase of the delay in the network with the rise in the penetration rate of AVs and CAVs can have a stable, an unstable, or a hybrid pattern. To optimize the system, we minimize a weighted summation of the experienced delay in the corridors and the total travel time in the urban network by optimizing the number of lanes of each type and the dynamic size of the CAV platoons. The results of the San Francisco case study show that implementing an optimal lane management strategy can reduce the experienced delay in the corridors up to 78% with a rise in the AV/CAV penetration rate. By dynamically controlling the size of the CAV platoons in the automated highway of the Bay Bridge, we limit the increase of the travel time in the downtown network as low as 5%.
Mahyar Amirgholy; Mehrdad Shahabi; H. Oliver Gao. Traffic automation and lane management for communicant, autonomous, and human-driven vehicles. Transportation Research Part C: Emerging Technologies 2020, 111, 477 -495.
AMA StyleMahyar Amirgholy, Mehrdad Shahabi, H. Oliver Gao. Traffic automation and lane management for communicant, autonomous, and human-driven vehicles. Transportation Research Part C: Emerging Technologies. 2020; 111 ():477-495.
Chicago/Turabian StyleMahyar Amirgholy; Mehrdad Shahabi; H. Oliver Gao. 2020. "Traffic automation and lane management for communicant, autonomous, and human-driven vehicles." Transportation Research Part C: Emerging Technologies 111, no. : 477-495.