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991.
992.
In this paper, we evaluate the adequacy of several performance measures for the evaluation of driving skills between different drivers. This work was motivated by the need for a training system that captures the driving skills of an expert driver and transfers the skills to novice drivers using a haptic-enabled driving simulator. The performance measures examined include traditional task performance measures, e.g., the mean position error, and a stochastic distance between a pair of hidden Markov models (HMMs), each of which is trained for an individual driver. The emphasis of the latter is on the differences between the stochastic somatosensory processes of human driving skills. For the evaluation, we developed a driving simulator and carried out an experiment that collected the driving data of an expert driver whose data were used as a reference for comparison and of many other subjects. The performance measures were computed from the experimental data, and they were compared to each other. We also collected the subjective judgement scores of the driver’s skills made by a highly-experienced external evaluator, and these subjective scores were compared with the objective performance measures. Analysis results showed that the HMM-based distance metric had a moderately high correlation between the subjective scores and it was also consistent with the other task performance measures, indicating the adequacy of the HMM-based metric as an objective performance measure for driving skill learning. The findings of this work can contribute to developing a driving simulator for training with an objective assessment function of driving skills. 相似文献
993.
Multifocus image fusion is the process of obtaining a single image from multiple partially focused images such that the newly formed image consists of the well-defined information extracted from each source image. This paper proposes the use of saliency of the source images based on Mutual Spectral Residual. Spectral Residual brings out the unique/salient features of an image in frequency domain. The idea of proposed mutual spectral residual is to emphasize the relative unique features of a source image with respect to the other source images. The relative unique features are utilized to form saliency maps for each source image. These saliency maps can clearly indicate the focused and defocused parts of an image. Based on the saliency maps obtained, the image fusion takes place in spatial domain. Visual inspection and quantitative evaluation of the fused images obtained by the proposed method, using different evaluation metrics, demonstrate its effectiveness over several existing image fusion methods. 相似文献
994.
Wenjuan Zhu Anup M. Vader Abhinav Chadda Ming C. Leu Xiaoqing F. Liu Jonathan B. Vance 《Virtual Reality》2013,17(2):125-136
This paper describes the development of a Wii remote (Wiimote)–based low-cost motion capture system and demonstrates its application for automated assembly simulation. Multiple Wiimotes are used to form a vision system to perform motion capture in 3D space. A hybrid algorithm for calibrating a multi-camera stereo vision system has been developed based on Zhang’s and Svoboda’s calibration algorithms. This hybrid algorithm has been evaluated and shown accuracy improvement over Svoboda’s algorithm for motion capture with multiple cameras. The captured motion data are used to automatically generate an assembly simulation of objects represented by CAD models in real time. The Wiimote-based motion capture system is practically attractive because it is inexpensive, wireless, and easily portable. Application examples have been developed for a single vision system with two Wiimotes to track the assembly of a microsatellite prototype frame and for an integrated vision system with four Wiimotes to track the assembly of a bookshelf. 相似文献
995.
Jonathan A. Czuba James L. Best Kevin A. Oberg Daniel R. Parsons P. Ryan Jackson Marcelo H. Garcia Peter Ashmore 《Journal of Great Lakes research》2011,37(3):480-493
An integrated multibeam echo sounder and acoustic Doppler current profiler field survey was conducted in July 2008 to investigate the morphodynamics of the St. Clair River at the outlet of Lake Huron. The principal morphological features of the upper St. Clair River included flow-transverse bedforms that appear weakly mobile, erosive bedforms in cohesive muds, thin non-cohesive veneers of weakly mobile sediment that cover an underlying cohesive (till or glacio-lacustrine) surface, and vegetation that covers the bed. The flow was characterized by acceleration as the banks constrict from Lake Huron into the St. Clair River, an approximately 1500-m long region of flow separation downstream from the Blue Water Bridge, and secondary flow connected to: i) channel curvature; ii) forcing of the flow by local bed topography, and iii) flow wakes in the lee side of ship wrecks. Nearshore, sand-sized, sediment from Lake Huron was capable of being transported into, and principally along, the banks of the upper St. Clair River by the measured flow. A comparison of bathymetric surveys conducted in 2007 and 2008 identifies that the gravel bed does undergo slow downstream movement, but that this movement does not appear to be generated by the mean flow, and could possibly be caused by ship-propeller-induced turbulence. The study results suggest that the measured mean flow and dredging within the channel have not produced major scour of the upper St. Clair River and that the recent fall in the level of Lake Huron is unlikely to have been caused by these mechanisms. 相似文献
996.
Roberto D. Ponce Felipe Vásquez Alejandra Stehr Patrick Debels Carlos Orihuela 《Water Resources Management》2011,25(10):2449-2466
This paper presents a contingent valuation study concerning landscape impacts generated by the construction of one dam (Baker
1) of the HIDROAYSEN hydropower project located in the Chilean Patagonia. A survey was used to collect information about citizens’
opinions towards the hydropower project in four major cities in Chile. Specifically, a One-and-One-Half-Bound (OOHB) willingness
to pay eliciting format was applied to capture citizens’ WTP. The economic loss, associated to the landscape impacts for people
living in urban areas of the country, is found to be approximately US$ 205 million, which is nearly 28% of the total investment.
Our results also show that the cities’ distance from the dam affects citizens’ willingness to pay. 相似文献
997.
Qiang Zhang Ben-De Wang Bin He Yong Peng Ming-Lei Ren 《Water Resources Management》2011,25(11):2683-2703
High accuracy forecasting of medium and long-term hydrological runoff is beneficial to reservoir operation and management.
A hybrid model is proposed for medium and long-term hydrological forecasting in this paper. The hybrid model consists of two
methods, Singular Spectrum Analysis (SSA) and Auto Regressive Integrated Moving Average (ARIMA). In this model, the time series
of annual runoff are first decomposed into several sub-series corresponding to some tendentious and periodic motions by using
SSA and then each sub-series is predicted, respectively, through an appropriate ARIMA model, and lastly a correction procedure
is conducted for the sum of the prediction results to ensure the superposed residual to be a pure random series. The annual
runoff data of two reservoirs in China are analyzed as case studies. The results have been compared with the predictions made
by ARIMA and Singular Spectrum Analysis-Linear Recurrent Formulae (SSA-LRF). It is shown that hybrid model has the best performance. 相似文献
998.
Assessment of Sustainable Yield of Karst Water in Huaibei,China 总被引:2,自引:1,他引:1
Dan Yin Longcang Shu Xunhong Chen Zhenlong Wang Mokhatar Eisa Mohammed 《Water Resources Management》2011,25(1):287-300
This paper presents the assessment of sustainable yield in the Huaibei karst water area of Anhui province, China. A review
of sustainable yield definition is introduced first in this paper, and sustainable development in karst areas is more difficult
due to the complicated hydrogeologic conditions. General hydrogeology of the study area is provided to characterize hydraulic
connections between the karst aquifer and an overlying porous aquifer. Groundwater level declines continuously due to over-exploitation
of the karst groundwater, and two layers of groundwater dropping funnel were formed in Huaibei. These problems not only threaten
the eco-geo-environment, but also compromise the water utilization which depends on the shallow porous water. A “critical
water level” is proposed in this study to assess the sustainable yield, and it is determined by the historical exploitation
data which represent the relationship between the karst water and the shallow porous water uses. A three layer Artificial
Neural Network (ANN) model is used to understand the complex relationship of the karst water level and its influencing factors.
Precipitation, exploitation and water level of latest period are chosen as the input nodes, seasonal records of water level
are simulated by the ANN model. The sustainable yield is calculated by the trail-and-error adjusting method, and is equal
to the pumping rate when the “critical water level” is maintained. The rate of 30.05 MCM/a is the sustainable yield for the
Huaibei karst area in 2008, and it is less than the real pumping rate of 35.92 MCM/a. This assessment is meaningful to the
management for the Huaibei karst water. 相似文献
999.
Optimizing Safe Yield Policy Implementation 总被引:1,自引:1,他引:0
The presented method enhances groundwater-mandated safe yield management. It is useful for settings that prevent sustained
yield or integrated management. To protect hydraulically connected surface water rights, the Utah government’s Cache Valley
groundwater management plan proposes that total pumping increase not exceed 84,431 m3/day. To determine how best to spatially distribute additional allowable pumping, stakeholders quantified limits defining
acceptable impacts on selected water resource indicators. A new simulation–optimization (S–O) algorithm used these limits
while computing optimal spatially distributed perennial yield or safe yield groundwater pumping extraction strategies. The
limits prevent unacceptable decreases in: head and net flow between aquifer and surface waters (rivers, surface/subsurface
drains, springs, lakes). The optimization objective function maximizes weighted pumping to provide water for 18 growing municipalities.
For 16 perennial yield scenarios, computed optimal pumping increases differ in protectiveness toward senior water rights,
and range from 16% to 103% of the state plan-proposed increase. Implementing a protective strategy would achieve 90% of the
storage changes needed to reach equilibrium within 23 years. Indicator potentiometric heads would reach equilibrium within
10–40 years. At equilibrium, an optimal Cache Valley perennial yield strategy acceptably minimizes net annual non-pumping
discharges. By comparison, multi-period 20-year transient groundwater mining optimizations allow more pumping in early years.
Pumping then must decline to satisfy seepage and head constraints through year 20. Adverse seepage impact would increase for
years thereafter. For situations governed by safe or perennial yield policy, equilibrium-based (steady-state) optimization
is very useful. It effectively develops optimal perennial yield strategies. 相似文献
1000.
Design of Barrages with Genetic Algorithm Based Embedded Simulation Optimization Approach 总被引:2,自引:2,他引:0
Raj Mohan Singh 《Water Resources Management》2011,25(2):409-429
Barrages are hydraulic structures constructed across rivers to divert flow into irrigation canals or power generation channels.
The most of these structures are founded on permeable foundation. The optimum cost of these structures is nonlinear function
of factors that cause the seepage forces under the structure. There is, however, no procedure to ascertain the basic barrage
parameters such as depth of sheet piles or cutoffs and the length and thickness of floor in a cost–effective manner. In this
paper, a nonlinear optimization formulation (NLOF), which consists of an objective function of minimizing total cost, is solved
using genetic algorithm (GA). The mathematical model that represents the subsurface flow is embedded in the NLOF. The applicability
of the approach has been illustrated with a typical example of barrage profile. The results obtained in this study shows drastic
cost savings when the proposed NLOF is solved using GA than that of using classical optimization technique and conventional
method. A parametric analysis has also been performed to study the effect of varying soil and hydrological conditions on design
parameters and on over all cost. 相似文献