In this paper, a new method for mobile robot map building based on grey system theory is presented, by which interpretation and integration of sonar readings can be solved robustly and efficiently. The conception of &...In this paper, a new method for mobile robot map building based on grey system theory is presented, by which interpretation and integration of sonar readings can be solved robustly and efficiently. The conception of 'grey number is introduced to model and handle the uncertainty of sonar reading. A new data fusion approach based on grey system theory is proposed to construct environment model. Map building experiments are performed both on a platform of simulation and a real mobile robot. Experimental results show that our method is robust and accurate.展开更多
A typical electronic communication system, such as GPS receiver, unmanned aerial vehicle's (UAV's) data link, and radar, faces multi-dimensional and complicated electromagnetic interference in operating environmen...A typical electronic communication system, such as GPS receiver, unmanned aerial vehicle's (UAV's) data link, and radar, faces multi-dimensional and complicated electromagnetic interference in operating environment. To measure the anti- interference performance of the electronic communication system in the complicated electromagnetic interference environment, a method of multi-dimensional and complicated electromagnetic interference hardware-in-the-loop simulation in an anechoic room is proposed. It takes into account the characteristics of interference signals and the positional relationship among interference, the receiver and the transmitter of the electronic communication system. It uses the grey relational method and the angular domain mapping error correction method to control the relevant parameters, the microwave switch and so on, thus achieving the approximately actual mapping of the outdoor multi-dimensional and complicated electromagnetic interference in the anechoic room. To verify the effectiveness of this method, the multi-dimensional and complicated electromagnetic interference of the UAV's data link is simulated as an example. The results show that the degree of correlation between the calculated signal to interference ratio of the data link receiver in the actual scene and the measured signal to interference ratio of the data link receiver simulated with this method in the anechoic room is 0.968 1, proving that the method is effective for simulating the complicated electromagnetic interference.展开更多
Background:Voxel-based morphometry(VBM)using structural brain MRI has been widely used for the assessment of impairment in Alzheimer’s disease(AD),but previous studies in VBM studies on AD remain inconsistent.Objecti...Background:Voxel-based morphometry(VBM)using structural brain MRI has been widely used for the assessment of impairment in Alzheimer’s disease(AD),but previous studies in VBM studies on AD remain inconsistent.Objective:We conducted meta-analyses to integrate the reported studies to determine the consistent grey matter alterations in AD based on VBM method.Methods:The PubMed,ISI Web of Science,EMBASE and Medline database were searched for articles between 1995 and June 2014.Manual searches were also conducted,and authors of studies were contacted for additional data.Coordinates were extracted from clusters with significant grey matter difference between AD patients and healthy controls(HC).Meta-analysis was performed using a new improved voxel-based meta-analytic method,Effect Size Signed Differential Mapping(ES-SDM).Results:Thirty data-sets comprising 960 subjects with AD and 1195 HC met inclusion criteria.Grey matter volume(GMV)reduction at 334 coordinates in AD and no GMV increase were found in the current meta-analysis.Significant reductions in GMV were robustly localized in the limbic regions(left parahippocampl gyrus and left posterior cingulate gyrus).In addition,there were GM decreases in right fusiform gyrus and right superior frontal gyrus.The findings remain largely unchanged in the jackknife sensitivity analyses.Conclusions:Our meta-analysis clearly identified GMV atrophy in AD.These findings confirm that the most prominent and replicable structural abnormalities in AD are in the limbic regions and contributes to the understanding of pathophysiology underlying AD.展开更多
As fossil fuel stocks are being depleted,alternative sources of energy must be explored.Consequently,traditional thermal power plants must coexist with renewable resources,such as wind,solar,and hydro units,and all-da...As fossil fuel stocks are being depleted,alternative sources of energy must be explored.Consequently,traditional thermal power plants must coexist with renewable resources,such as wind,solar,and hydro units,and all-day planning and operation techniques are necessary to safeguard nature while meeting the current demand.The fundamental components of contemporary power systems are the simultaneous decrease in generation costs and increase in the available transfer capacity(ATC)of current systems.Thermal units are linked to sources of renewable energy such as hydro,wind,and solar power,and are set up to run for 24 h.By contrast,new research reports that various chaotic maps are merged with various existing optimization methodologies to obtain better results than those without the inclusion of chaos.Chaos seems to increase the performance and convergence properties of existing optimization approaches.In this study,selfish animal tendencies,mathematically represented as selfish herd optimizers,were hybridized with chaotic phenomena and used to improve ATC and/or reduce generation costs,creating a multi-objective optimization problem.To evaluate the performance of the proposed hybridized optimization technique,an optimal power flow-based ATC was enforced under various hydro-thermal-solar-wind conditions,that is,the renewable energy source-thermal scheduling concept,on IEEE 9-bus,IEEE 39-bus,and Indian Northern Region Power Grid 246-bus test systems.The findings show that the proposed technique outperforms existing well-established optimization strategies.展开更多
基金This project was supported by the National High-Tech Research and Development Plan (2001AA422140) National Science Foundation (69889501, 60105005).
文摘In this paper, a new method for mobile robot map building based on grey system theory is presented, by which interpretation and integration of sonar readings can be solved robustly and efficiently. The conception of 'grey number is introduced to model and handle the uncertainty of sonar reading. A new data fusion approach based on grey system theory is proposed to construct environment model. Map building experiments are performed both on a platform of simulation and a real mobile robot. Experimental results show that our method is robust and accurate.
基金supported by the National Natural Science Foundation of China(61571368)the certain Ministry Foundation(2014607B006)
文摘A typical electronic communication system, such as GPS receiver, unmanned aerial vehicle's (UAV's) data link, and radar, faces multi-dimensional and complicated electromagnetic interference in operating environment. To measure the anti- interference performance of the electronic communication system in the complicated electromagnetic interference environment, a method of multi-dimensional and complicated electromagnetic interference hardware-in-the-loop simulation in an anechoic room is proposed. It takes into account the characteristics of interference signals and the positional relationship among interference, the receiver and the transmitter of the electronic communication system. It uses the grey relational method and the angular domain mapping error correction method to control the relevant parameters, the microwave switch and so on, thus achieving the approximately actual mapping of the outdoor multi-dimensional and complicated electromagnetic interference in the anechoic room. To verify the effectiveness of this method, the multi-dimensional and complicated electromagnetic interference of the UAV's data link is simulated as an example. The results show that the degree of correlation between the calculated signal to interference ratio of the data link receiver in the actual scene and the measured signal to interference ratio of the data link receiver simulated with this method in the anechoic room is 0.968 1, proving that the method is effective for simulating the complicated electromagnetic interference.
基金by grants from the National Natural Science Foundation of China(81471309,81371406,81171209)the Natural Science Foundation of Beijing(No.7152096)+3 种基金the Shandong Provincial Outstanding Medical Academic Professional ProgramShandong Provincial Collaborative Innovation Center for Neurodegenerative DisordersQingdao Key Health Discipline Development FundQingdao Outstanding Health Professional Development Fund.
文摘Background:Voxel-based morphometry(VBM)using structural brain MRI has been widely used for the assessment of impairment in Alzheimer’s disease(AD),but previous studies in VBM studies on AD remain inconsistent.Objective:We conducted meta-analyses to integrate the reported studies to determine the consistent grey matter alterations in AD based on VBM method.Methods:The PubMed,ISI Web of Science,EMBASE and Medline database were searched for articles between 1995 and June 2014.Manual searches were also conducted,and authors of studies were contacted for additional data.Coordinates were extracted from clusters with significant grey matter difference between AD patients and healthy controls(HC).Meta-analysis was performed using a new improved voxel-based meta-analytic method,Effect Size Signed Differential Mapping(ES-SDM).Results:Thirty data-sets comprising 960 subjects with AD and 1195 HC met inclusion criteria.Grey matter volume(GMV)reduction at 334 coordinates in AD and no GMV increase were found in the current meta-analysis.Significant reductions in GMV were robustly localized in the limbic regions(left parahippocampl gyrus and left posterior cingulate gyrus).In addition,there were GM decreases in right fusiform gyrus and right superior frontal gyrus.The findings remain largely unchanged in the jackknife sensitivity analyses.Conclusions:Our meta-analysis clearly identified GMV atrophy in AD.These findings confirm that the most prominent and replicable structural abnormalities in AD are in the limbic regions and contributes to the understanding of pathophysiology underlying AD.
文摘As fossil fuel stocks are being depleted,alternative sources of energy must be explored.Consequently,traditional thermal power plants must coexist with renewable resources,such as wind,solar,and hydro units,and all-day planning and operation techniques are necessary to safeguard nature while meeting the current demand.The fundamental components of contemporary power systems are the simultaneous decrease in generation costs and increase in the available transfer capacity(ATC)of current systems.Thermal units are linked to sources of renewable energy such as hydro,wind,and solar power,and are set up to run for 24 h.By contrast,new research reports that various chaotic maps are merged with various existing optimization methodologies to obtain better results than those without the inclusion of chaos.Chaos seems to increase the performance and convergence properties of existing optimization approaches.In this study,selfish animal tendencies,mathematically represented as selfish herd optimizers,were hybridized with chaotic phenomena and used to improve ATC and/or reduce generation costs,creating a multi-objective optimization problem.To evaluate the performance of the proposed hybridized optimization technique,an optimal power flow-based ATC was enforced under various hydro-thermal-solar-wind conditions,that is,the renewable energy source-thermal scheduling concept,on IEEE 9-bus,IEEE 39-bus,and Indian Northern Region Power Grid 246-bus test systems.The findings show that the proposed technique outperforms existing well-established optimization strategies.