7 results
Search Results
2. Dynamics in the Fitness-Income plane: Brazilian states vs World countries.
- Author
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Operti, Felipe G., Pugliese, Emanuele, Jr.Andrade, José S., Pietronero, Luciano, and Gabrielli, Andrea
- Subjects
ALGORITHMS ,PHYSICAL fitness ,GROSS domestic product ,ECONOMICS - Abstract
In this paper we introduce a novel algorithm, called Exogenous Fitness, to calculate the Fitness of subnational entities and we apply it to the states of Brazil. In the last decade, several indices were introduced to measure the competitiveness of countries by looking at the complexity of their export basket. Tacchella et al (2012) developed a non-monetary metric called Fitness. In this paper, after an overview about Brazil as a whole and the comparison with the other BRIC countries, we introduce a new methodology based on the Fitness algorithm, called Exogenous Fitness. Combining the results with the Gross Domestic Product per capita (GDP
p ), we look at the dynamics of the Brazilian states in the Fitness-Income plane. Two regimes are distinguishable: one with high predictability and the other with low predictability, showing a deep analogy with the heterogeneous dynamics of the World countries. Furthermore, we compare the ranking of the Brazilian states according to the Exogenous Fitness with the ranking obtained through two other techniques, namely Endogenous Fitness and Economic Complexity Index. [ABSTRACT FROM AUTHOR]- Published
- 2018
- Full Text
- View/download PDF
3. Using Tensor Completion Method to Achieving Better Coverage of Traffic State Estimation from Sparse Floating Car Data.
- Author
-
Ran, Bin, Song, Li, Zhang, Jian, Cheng, Yang, and Tan, Huachun
- Subjects
TRAFFIC engineering ,ESTIMATION theory ,PROBLEM solving ,STATISTICAL correlation ,MISSING data (Statistics) - Abstract
Traffic state estimation from the floating car system is a challenging problem. The low penetration rate and random distribution make available floating car samples usually cover part space and time points of the road networks. To obtain a wide range of traffic state from the floating car system, many methods have been proposed to estimate the traffic state for the uncovered links. However, these methods cannot provide traffic state of the entire road networks. In this paper, the traffic state estimation is transformed to solve a missing data imputation problem, and the tensor completion framework is proposed to estimate missing traffic state. A tensor is constructed to model traffic state in which observed entries are directly derived from floating car system and unobserved traffic states are modeled as missing entries of constructed tensor. The constructed traffic state tensor can represent spatial and temporal correlations of traffic data and encode the multi-way properties of traffic state. The advantage of the proposed approach is that it can fully mine and utilize the multi-dimensional inherent correlations of traffic state. We tested the proposed approach on a well calibrated simulation network. Experimental results demonstrated that the proposed approach yield reliable traffic state estimation from very sparse floating car data, particularly when dealing with the floating car penetration rate is below 1%. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
4. Evaluating the influential priority of the factors on insurance loss of public transit.
- Author
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Zhang, Wenhui, Su, Yongmin, Ke, Ruimin, and Chen, Xinqiang
- Subjects
PUBLIC transit ,INSURANCE claims ,GREY relational analysis ,K-means clustering - Abstract
Understanding correlation between influential factors and insurance losses is beneficial for insurers to accurately price and modify the bonus-malus system. Although there have been a certain number of achievements in insurance losses and claims modeling, limited efforts focus on exploring the relative role of accidents characteristics in insurance losses. The primary objective of this study is to evaluate the influential priority of transit accidents attributes, such as the time, location and type of accidents. Based on the dataset from Washington State Transit Insurance Pool (WSTIP) in USA, we implement several key algorithms to achieve the objectives. First, K-means algorithm contributes to cluster the insurance loss data into 6 intervals; second, Grey Relational Analysis (GCA) model is applied to calculate grey relational grades of the influential factors in each interval; in addition, we implement Naive Bayes model to compute the posterior probability of factors values falling in each interval. The results show that the time, location and type of accidents significantly influence the insurance loss in the first five intervals, but their grey relational grades show no significantly difference. In the last interval which represents the highest insurance loss, the grey relational grade of the time is significant higher than that of the location and type of accidents. For each value of the time and location, the insurance loss most likely falls in the first and second intervals which refers to the lower loss. However, for accidents between buses and non-motorized road users, the probability of insurance loss falling in the interval 6 tends to be highest. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
5. Mediterranean California’s water use future under multiple scenarios of developed and agricultural land use change.
- Author
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Wilson, Tamara S., Sleeter, Benjamin M., and Cameron, D. Richard
- Subjects
WATER supply ,WATER use ,CLIMATE change ,AGRICULTURAL intensification ,URBANIZATION & the environment - Abstract
With growing demand and highly variable inter-annual water supplies, California’s water use future is fraught with uncertainty. Climate change projections, anticipated population growth, and continued agricultural intensification, will likely stress existing water supplies in coming decades. Using a state-and-transition simulation modeling approach, we examine a broad suite of spatially explicit future land use scenarios and their associated county-level water use demand out to 2062. We examined a range of potential water demand futures sampled from a 20-year record of historical (1992–2012) data to develop a suite of potential future land change scenarios, including low/high change scenarios for urbanization and agriculture as well as “lowest of the low” and “highest of the high” anthropogenic use. Future water demand decreased 8.3 billion cubic meters (Bm
3 ) in the lowest of the low scenario and decreased 0.8 Bm3 in the low agriculture scenario. The greatest increased water demand was projected for the highest of the high land use scenario (+9.4 Bm3 ), high agricultural expansion (+4.6 Bm3 ), and high urbanization (+2.1 Bm3 ) scenarios. Overall, these scenarios show agricultural land use decisions will likely drive future demand more than increasing municipal and industrial uses, yet improved efficiencies across all sectors could lead to potential water use savings. Results provide water managers with information on diverging land use and water use futures, based on historical, observed land change trends and water use histories. [ABSTRACT FROM AUTHOR]- Published
- 2017
- Full Text
- View/download PDF
6. Simulated bat populations erode when exposed to climate change projections for western North America.
- Author
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Hayes, Mark A. and Adams, Rick A.
- Subjects
BATS ,LACTATION ,FRINGED myotis ,CLIMATE change ,SPECIES diversity - Abstract
Recent research has demonstrated that temperature and precipitation conditions correlate with successful reproduction in some insectivorous bat species that live in arid and semiarid regions, and that hot and dry conditions correlate with reduced lactation and reproductive output by females of some species. However, the potential long-term impacts of climate-induced reproductive declines on bat populations in western North America are not well understood. We combined results from long-term field monitoring and experiments in our study area with information on vital rates to develop stochastic age-structured population dynamics models and analyzed how simulated fringed myotis (Myotis thysanodes) populations changed under projected future climate conditions in our study area near Boulder, Colorado (Boulder Models) and throughout western North America (General Models). Each simulation consisted of an initial population of 2,000 females and an approximately stable age distribution at the beginning of the simulation. We allowed each population to be influenced by the mean annual temperature and annual precipitation for our study area and a generalized range-wide model projected through year 2086, for each of four carbon emission scenarios (representative concentration pathways RCP2.6, RCP4.5, RCP6.0, RCP8.5). Each population simulation was repeated 10,000 times. Of the 8 Boulder Model simulations, 1 increased (+29.10%), 3 stayed approximately stable (+2.45%, +0.05%, -0.03%), and 4 simulations decreased substantially (-44.10%, -44.70%, -44.95%, -78.85%). All General Model simulations for western North America decreased by >90% (-93.75%, -96.70%, -96.70%, -98.75%). These results suggest that a changing climate in western North America has the potential to quickly erode some forest bat populations including species of conservation concern, such as fringed myotis. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
7. Using Tensor Completion Method to Achieving Better Coverage of Traffic State Estimation from Sparse Floating Car Data
- Author
-
Yang Cheng, Jian Zhang, Huachun Tan, Li Song, and Bin Ran
- Subjects
Computer science ,Aviation ,Intelligence ,lcsh:Medicine ,Social Sciences ,Transportation ,02 engineering and technology ,Geographical locations ,Mathematical and Statistical Techniques ,0202 electrical engineering, electronic engineering, information engineering ,Range (statistics) ,Computer Science::Networking and Internet Architecture ,Psychology ,lcsh:Science ,Intelligent transportation system ,Principal Component Analysis ,Multidisciplinary ,geography.geographical_feature_category ,Applied Mathematics ,Simulation and Modeling ,05 social sciences ,Floating car data ,Transportation Infrastructure ,Physical Sciences ,Engineering and Technology ,020201 artificial intelligence & image processing ,Algorithm ,Algorithms ,Statistics (Mathematics) ,Network analysis ,Research Article ,Optimization ,Computer and Information Sciences ,Research and Analysis Methods ,Civil Engineering ,Wisconsin ,0502 economics and business ,Computer Simulation ,Tensor ,Statistical Methods ,Traffic generation model ,050210 logistics & transportation ,geography ,business.industry ,lcsh:R ,Cognitive Psychology ,Biology and Life Sciences ,Computing Methods ,United States ,Roads ,ComputerSystemsOrganization_MISCELLANEOUS ,Multivariate Analysis ,North America ,Cognitive Science ,lcsh:Q ,State (computer science) ,People and places ,business ,Automobiles ,Mathematics ,Water well ,Neuroscience - Abstract
Traffic state estimation from the floating car system is a challenging problem. The low penetration rate and random distribution make available floating car samples usually cover part space and time points of the road networks. To obtain a wide range of traffic state from the floating car system, many methods have been proposed to estimate the traffic state for the uncovered links. However, these methods cannot provide traffic state of the entire road networks. In this paper, the traffic state estimation is transformed to solve a missing data imputation problem, and the tensor completion framework is proposed to estimate missing traffic state. A tensor is constructed to model traffic state in which observed entries are directly derived from floating car system and unobserved traffic states are modeled as missing entries of constructed tensor. The constructed traffic state tensor can represent spatial and temporal correlations of traffic data and encode the multi-way properties of traffic state. The advantage of the proposed approach is that it can fully mine and utilize the multi-dimensional inherent correlations of traffic state. We tested the proposed approach on a well calibrated simulation network. Experimental results demonstrated that the proposed approach yield reliable traffic state estimation from very sparse floating car data, particularly when dealing with the floating car penetration rate is below 1%.
- Published
- 2016
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