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Delineation of an Urban Community Life Circle Based on a Machine-Learning Estimation of Spatiotemporal Behavioral Demand 被引量:3
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作者 LI Chunjiang XIA Wanqu CHAI Yanwei 《Chinese Geographical Science》 SCIE CSCD 2021年第1期27-40,共14页
Delineating life circles is an essential prerequisite for urban community life circle planning. Recent studies combined the environmental contexts with residents’ global positioning system(GPS) data to delineate the ... Delineating life circles is an essential prerequisite for urban community life circle planning. Recent studies combined the environmental contexts with residents’ global positioning system(GPS) data to delineate the life circles. This method, however, is constrained by GPS data, and it can only be applied in the GPS surveyed communities. To address this limitation, this study developed a generalizable delineation method without the constraint of behavioral data. According to previous research, the community life circle consists of the walking-accessible range and internal structure. The core task to develop the generalizable method was to estimate the spatiotemporal behavioral demand for each plot of land to acquire the internal structure of the life circle, as the range can be delineated primarily based on environmental data. Therefore, behavioral demand estimation models were established through logistic regression and machine learning techniques, including decision trees and ensemble learning. The model with the lowest error rate was chosen as the final estimation model for each type of land. Finally, we used a community without GPS data as an example to demonstrate the effectiveness of the estimation models and delineation method. This article extends the existing literature by introducing spatiotemporal behavioral demand estimation models, which learn the relationships between environmental contexts, population composition and the existing delineated results based on GPS data to delineate the internal structure of the community life circle without employing behavioral data. Furthermore, the proposed method and delineation results also contributes to facilities adjustments and location selections in life circle planning, people-oriented transformation in urban planning, and activity space estimation of the population in evaluating and improving the urban policies. 展开更多
关键词 community life circle spatiotemporal behavioral demand demand estimation model decision tree ensemble learning
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DEMAND ESTIMATION AND ASSORTMENT PLANNING IN WIRELESS COMMUNICATIONS 被引量:2
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作者 Xiaoyu Ma Tianhu Deng Boxiong Lan 《Journal of Systems Science and Systems Engineering》 SCIE EI CSCD 2016年第4期398-423,共26页
This paper provides an efficient and useful approach for demand estimation and assortment planning of cell phone cards in wireless communication industry. We use maximum likelihood estimation to estimate the primary d... This paper provides an efficient and useful approach for demand estimation and assortment planning of cell phone cards in wireless communication industry. We use maximum likelihood estimation to estimate the primary demand and substitution probability of each cell phone card based on historical sales data. This estimation model is nonlinear, so we transform it to a mixed integer linear programming model by logarithmic transformations and piecewise'linear approximation. On the basis of the estimation results, we can make assortment planning. Considering the resource of cell phone cards is limited, we jointly optimize the assortment and quantity planning of cell phone cards. In numerical study, we apply our approach to a large mobile service provider in China and frod our approach can increase the revenue of this mobile service provider by 23.69%. Sensitivity analysis shows the mobile service provider should provide more assortments to increase revenue when the types of cell phone cards that can be assigned to each store are limited. 展开更多
关键词 demand estimation substitution behavior assortment planning OPTIMIZATION wireless communications
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An improved modal pushover analysis procedure for estimating seismic demands of structures 被引量:5
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作者 毛建猛 翟长海 谢礼立 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2008年第1期25-31,共7页
The pushover analysis (POA) procedure is difficult to apply to high-rise buildings, as it cannot account for the contributions of higher modes. To overcome this limitation, a modal pushover analysis (MPA) procedur... The pushover analysis (POA) procedure is difficult to apply to high-rise buildings, as it cannot account for the contributions of higher modes. To overcome this limitation, a modal pushover analysis (MPA) procedure was proposed by Chopra et al. (2001). However, invariable lateral force distributions are still adopted in the MPA. In this paper, an improved MPA procedure is presented to estimate the seismic demands of structures, considering the redistribution of inertia forces after the structure yields. This improved procedure is verified with numerical examples of 5-, 9- and 22-story buildings. It is concluded that the improved MPA procedure is more accurate than either the POA procedure or MPA procedure. In addition, the proposed procedure avoids a large computational effort by adopting a two-phase lateral force distribution.. 展开更多
关键词 seismic demand estimation pushover analysis improved modal pushover analysis two-phase lateral forcedistribution capacity curve
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Trade-off between accuracy, cost, and QoS using a beacon-on-demand strategy and Kalman filtering over a VANET
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作者 Zineb Squalli Houssaini Imane Zaimi +2 位作者 Maroua Drissi Mohammed Oumsis Said El Alaoui Ouatik 《Digital Communications and Networks》 SCIE 2018年第1期13-26,共14页
Vehicular Ad-hoc Networks (VANETs) have been suggested as an active and powerful field of research to mitigate environmental problems and challenges. The main challenge in a VANET is to ensure routing with a good Qu... Vehicular Ad-hoc Networks (VANETs) have been suggested as an active and powerful field of research to mitigate environmental problems and challenges. The main challenge in a VANET is to ensure routing with a good Quality of Service (QoS). The Greedy Perimeter Stateless Routing (GPSR) protocol is one of the most promising position- based routing mechanisms used to overcome this challenge. Its effectiveness depends entirely on the information on a node's mobility and the precision of this information. By broadcasting periodic beaconing within trans- mission boundary ranges, GPSR can manage neighbors' mobility information and maintain up-to-date lists of neighbours. Nevertheless, information on the position of a neighboring vehicle quickly becomes outdated, which negatively influences the efficiency of the routing. In order to monitor information mobility and to increase the QoS in this challenging area, position estimation needs to he considered. Thus, in this study, we examine the position estimation problem, and propose an improvement to the GPSR protocol, named KF-GPSR, where each vehicle estimates in real time the position of its neighbors using the Kalman filter algorithm. Indeed, by employing this strong estimation technique, it is possible to reduce consid- erably the frequency of exchanged beacon packets, while maintaining high position accuracy. For greater reliability, we also propose an extension to KF-GPSR, called BOD-KF-GPSR, that uses the "beacon-on-demand" process only if a node needs to rediscover its neighborhood. Simulation experiments using the network simulator NS-2 are presented to demonstrate the ability and usefulness of our two proposals. Here, we compare the pro- posed protocols against diverse common protocols: GPSR, AODV, DSR, and ZRP. The results show that BOD-KF- GPSR achieves a significant enhancement in terms of its packet delivery ratio, routing cost, normalized routing load, end-to-end delay, and throughput. 展开更多
关键词 VANET I(alman filter GPSR Beacon on demand estimation Routing QoS
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Bilding Dmage Level Based According to Distance Image Contrast.
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作者 Liwei Chen 《International Journal of Technology Management》 2015年第10期76-79,共4页
Estimation method of building damage level was introduced for the accurate and effective estimation of damage extent and relief goods demand according to long-distance image contrast. In order to obtain completion deg... Estimation method of building damage level was introduced for the accurate and effective estimation of damage extent and relief goods demand according to long-distance image contrast. In order to obtain completion degree of building edge extracted from long-distance images before and after disaster, the concentration ratio was analyzed with Hough transformation. Based on the maximum posterior probability, estimation method of affected population was designed to accurately estimate victim population, which can be directly reflected by fugitive population. Moreover, on basis of escape route and fugitive population, demand assignment algorithm by backward calculation was designed to improve rescue efficiency. 展开更多
关键词 emergency rescue demand estimation Hough transformation maximum posterior probability
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Technical review of electric vehicle charging distribution models with considering driver behaviors impacts
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作者 Wei Lin Heng Wei +1 位作者 Lan Yang Xiangmo Zhao 《Journal of Traffic and Transportation Engineering(English Edition)》 EI CSCD 2024年第4期643-666,共24页
Amassive market penetration of electric vehicles(EVs)associated with nonnegligible energy consumption and environmental issues has imposed a big challenge on evaluating electrical power distribution and related transp... Amassive market penetration of electric vehicles(EVs)associated with nonnegligible energy consumption and environmental issues has imposed a big challenge on evaluating electrical power distribution and related transportation facilities improvement in response to the largescale EV charging service need.Strategical deployment of EV charging stations including location and determination ofnumber of slowcharging stations and fast charging stationshas become an emerging concern and one of the most pressing needs in planning.This paper conducts a comprehensive survey of EV charging demand and distribution models with consideration of realistic driver behaviors impacts.This is currently a shortage in academic literature,but indeed has drawn practical attention in the strategic planning process.To address the need,this paper presents an in-depth literature review of relevant studies that have identified different types of EV charging facilities,needs or concerns that are considered into EV charging demand and distribution modeling,alongside critical impacting factor identification,mathematical relationshipsof the contributing factorsandEVchargingdemand and distribution modeling.Key findings from the current literature are summarized with strategies for optimized plan of charging station deployments(i.e.,location and related number of charging station),in an attempt to provide a valuable reference for interested readers. 展开更多
关键词 Charging demand estimation Strategic charging station deployment Electric vehicle Driver behavior
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Code Sharing and Merger: Continental, Delta and Northwest
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作者 Caixia Shen 《Frontiers of Economics in China-Selected Publications from Chinese Universities》 2015年第4期643-663,共21页
When Delta joined the code share between Continental and Northwest in 2003, these three legacy carriers formed the only three-way U.S. domestic code sharing partnership. In 2008, Delta and Northwest announced their in... When Delta joined the code share between Continental and Northwest in 2003, these three legacy carriers formed the only three-way U.S. domestic code sharing partnership. In 2008, Delta and Northwest announced their intention to merge. The merger was granted by the Department of Justice six months later. This paper analyzes the effects of the three-way code share and the effects of the merger between these two previous code sharing partners. I find both competitive effects and anti-competitive effects of code sharing, i.e., mean market price decrease in non-hub markets and price increase in hub-to-hub markets. Meanwhile, passenger volume increases significantly. Moreover, rivals' responses are to move price in the same direction as code sharing partners. I find an increase in Herfindahl-Hirschman Index (HHI) and a reduction in traffic after the merger. Specifically, HHI increases for over 1,000 points in markets where merging airlines were either duopolistic or with a third carrier. Pre-merger code sharing markets experience an increase in HHI due to the disappearance of the code sharing contract. Low cost carrier entry mitigates merger effects. 展开更多
关键词 AIRLINE code sharing regulation demand estimation
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