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271.
Jennifer D. Ruiz-Ramírez Jorge I. Euán-Ávila Víctor H. Rivera-Monroy 《Coastal management》2019,47(1):23-43
We evaluated the potential economic impacts of increasing sea level rise (SLR) along the Mexican Caribbean where there are major gaps in our understanding of the mechanisms controlling flooding duration and frequency associated to future ecological and economic impacts. We determined the negative economic impact of SLR on infrastructure in the largest urban centers (Cancun, Isla Mujeres, Playa del Carmen, Puerto Morelos and Cozumel) in the state of Quintana Roo (Mexico) that are considered the largest tourism “hot spots” (resort cities) in the country. The tourism industry in this coastal area injects >8 billion dollars year?1 to the Mexican economy. Our conservative economic assessment regarding the impact of SLR, under a 1?m scenario for all coastal cities is $330 million USD. Further projections for worst scenarios (SLR >2 m) show a non-linear trend where the cost of inaction can reach up to $1.4 billion USD (2?m SLR scenario) and $2.3 billion USD (3?m SLR scenario). This potential loss of infrastructure, as construction cost, is staggering and represents a robust baseline to start evaluating with more detail future impacts of climate variability and change on the Mexican Caribbean coastline. 相似文献
272.
273.
Patel Hersila H. Messiah Sarah E. Hansen Eric D’Agostino Emily M. 《Transportation》2021,48(5):2315-2333
Transportation - Transportation vulnerability, defined as lack of access to transportation resulting in financial, social, or health consequences, reduces quality of life. While research has... 相似文献
274.
Kyongsu Yi Karl Hedrick Seong-Chul Lee 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》1999,31(4):233-261
This paper presents methods for identifying the tire-road friction coefficient. The proposed methods are: an observer-based least square method and an observer/filtered-regressor-based method. These methods were designed assuming that some of the states are not available since physical parameter identification methods developed assuming that the system states are available are not attractive from a practical point of view. The observer is used to estimate signals which are difficult or expensive to measure. Using the estimated states of the system and the filtered-regressor, the parameter estimates are obtained. The proposed methods are evaluated on an eight state nonlinear vehicle/transmission simulation model with a Bakker-Pacejka's formula tire model. Vehicle tests have been performed on dry and wet roads to verify the performance of the methods. It has been shown through simulations and vehicle tests how the RPM sensors can be used with observer based identification methods to estimate the tire-road friction from measurements of engine rpm, transmission output speed and wheel speed. The proposed methods will be useful in the implementation and adaptation of vehicle collision warning/avoidance algorithm since the tire-road friction can be estimated only using the RPM sensors which are currently being used in production vehicles. 相似文献
275.
This paper presents a Geographic Information Systems (GIS) as a tool which can help highway engineers review a completed highway design to improve its constructability. The GIS can link different data sets together using geographical location as the common key between the data sets to perform various spatial operations. In this paper, the GIS is used to integrate various highway design data using a common milepost referencing system. The GIS allows the integration of the highway design information by establishing common spatial relationships between various highway design features and their geographical locations. The GIS can provide a comprehensive platform upon which all aspects of the highway project review process can be built. This paper also addresses the interface of GIS with the existing highway project data bases and computer-aided design files. The proposed GIS-based highway design review system can improve the constructability of the highway design at an early design review stage. 相似文献
276.
277.
Recent interpretations of carbon flux data and deep-sea processes have led to a reconsideration of the role of dissolved organic carbon (DOC) in supporting water column remineralization and other mid-water biogeochemical transformations (Suzuki et al., 1985; Cho and Azam, 1988; Karl et al., 1988; Christensen et al., 1989; Naqvi and Shailaja, 1993). To date, there have been no direct comparisons of particulate carbon flux data with water column metabolic rates. Here, for the first time, particulate carbon flux and respiratory electron transport activity (from which metabolic CO2 production is derived), have been monitored simultaneously for one year in the same area of the northwestern Mediterranean Sea. In the aphotic layer (200–1000 m), particulate organic carbon (POC) can support only 20% of the overall organic matter remineralization. Remineralization rates are consistent with recent calculations of DOC exported from the euphotic layer in this area, confirming the vital importance of DOC in maintaining deep-water metabolism. This finding would apply to other regions of mesotrophic and oligotrophic production and thus affect our understanding of carbon recycling in the water column, new production and O2 utilization. 相似文献
278.
Bruce D. Spear 《Transportation》1996,23(3):215-240
In 1992, the Federal Highway Administration awarded small research contracts to four teams of transportation researchers to design alternative approaches for improving the urban travel demand forecasting process. The purpose of these contracts was to enable each research team to explain how transportation planning models could and should be improved to meet the new forecasting requirements brought on by recent legislation, to address the impacts of new transportation technology, and to exploit the travel behavior theories and methodologies that have developed over the past two decades.This paper presents a summary and synthesis of the ideas which emerged from the four research reports. Its purpose is to identify common themes suggested by several of the research teams, to point out what appear to be critical elements missing from some approaches, and to combine the best aspects of the four approaches into a research plan for improving the current generation of travel demand models.Abbreviations CAAA
Clean Air Act Amendments
- FHWA
Federal Highway Administration
- GIS
Geographic Information System
- IIA
Independence of Irrelevant Alternatives
- IT
Information Technology
- IVHS
Intelligent Vehicle Highway System
- SUE
Stochastic User Equilibrium
- TCM
Transportation Control Measures
- UTPS
Urban Transportation Planning System
- VMT
Vehicle Miles of Travel
The paper was prepared as a report for the Federal Highway Administration. 相似文献
279.
Non-linear finite element analysis is used to assess the static collapse strength of a sample tubular T-joint configuration subjected to compressive brace loading. Two series of models are used to assess the effects of varying the chord length L, one series having simply supported chord ends and the other having fixed chord ends. It is shown that chord length and boundary conditions can have a significant influence on static collapse loads. The results are discussed in the light of current design procedures. 相似文献
280.
Jaehyung Lee Hong Hee Yoo Jang Moo Lee 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》1997,28(4):261-271
This paper presents a modeling method to analyze the frequency characteristics of a suspension system. The method employs the superelement and lumped methods for structural modeling of flexible bodies, and it is incorporated with a multibidy dynamics formulation in which joint nonlinearities can be considered effectively. To verify the accuracy of the results obtained by the modeling method, a quarter car test was made. Test results showed that the computational model provided fairly accurate frequency characteristics for the suspension system. Other useful conclusions were also drawn from this study. 相似文献