机动车保有量增加引发的环境污染与交通拥堵日趋严重,人们对于缓解交通拥堵的交通流预测方法研究逐渐重视.本文对厦门市城市道路的RFID(Radio frequency identification)数据预处理后进行相似性分析,选取相似性系数和不稳定系数为指标...机动车保有量增加引发的环境污染与交通拥堵日趋严重,人们对于缓解交通拥堵的交通流预测方法研究逐渐重视.本文对厦门市城市道路的RFID(Radio frequency identification)数据预处理后进行相似性分析,选取相似性系数和不稳定系数为指标来表征路段交通流的相似度,并判断阈值以及对应交通状态下的路段交通转移量,最终以数据相似性为基础,建立交通流预测模型.选取10条城市道路RFID数据验证,其平均绝对误差为0.061,证明本文提出模型的可行性.展开更多
Background Magnetic resonance spectroscopy （MRS） is one method that can examine noninvasively the alive specimen of the organ, metabolism of the organ and cell, and the biochemistry change. MRS provides the biochemi...Background Magnetic resonance spectroscopy （MRS） is one method that can examine noninvasively the alive specimen of the organ, metabolism of the organ and cell, and the biochemistry change. MRS provides the biochemistry information that may be used to diagnose tumors or differentiate the malignant tumor from benign. The objective of this study is to investigate the benign and malignant bone and soft tissue tumors by 1H-MR spectroscopy （^1H-MRS） on a 3 Tesla MR scanner, then to assess the usefulness of ^1H-MRS in diagnosing bone and soft tissue tumors and distinguishing benign from malignant tumors.Methods Fifty-six patients with bone and soft tissue tumors proved clinically and pathologically were examined with ^1H-MRS. ^1H-MRS was performed to study malignant musculoskeletal tumors, benign tumors and normal muscle adjacent to lesions to analyze the characteristics, and single-voxel point-resolved spectroscopy sequence was used. Proton brain exam-single voxel of ^1H-MRS which directly appeared in the spectrum, was observed to find the peak height of choline compounds （Cho） opposite to the creatine （Cr）, and whether there was a Cho peak. Metabolite values were calculated automatically from the area under each metabolite peak by the Functool 3.1 software. Metabolite ratios of Cho/Cr were manually calculated. Then according to the results, it was judged whether there existed benign or malignant tumors. The Kappa statistical test was used to analyze the MRS results, the histopathology data and the surgical situation. Statistics processing was performed using the software packaqe SPSS11.5 for Windows.Results ^1H-MRS spectra style of bone and soft tissue tumors was different from that of normal muscle, and differences also existed between benign and malignant tumors. Choline level in malignant tumor was markedly higher than that in benign tumors. Cho/Cr in malignant tumor was higher than in benign tumor significantly （P〈0.05）. The true positive rate of bone and soft tissue between benign and malignant tumors was 34/36, the true negative rate was 15/18, the false positive rate was 3/18 and the false negative rate was 2/36. Therefore in the group, sensitivity of the ^1H-MRS was 94% （34/36）, specificity was 83% （15/18）, positive predictive value was 92% （34/37）, negative predictive value was 88% （15/17） and the accuracy rate was 91% （49/54）. The MRS results and the histopathology inspection conclusions had very good uniformity. The K value was 0.76±0.10 （P 〈0.01）.Conclusions The increase of Cho level measured by ^1H-MRS is related to the bone and soft tissue malignant tumor. Cho/Cr in malignant tumor was higher than in benign tumor, so they will play a vital role in the diagnosis and differential diagnosis of bone and soft tissue tumors.展开更多
文摘机动车保有量增加引发的环境污染与交通拥堵日趋严重,人们对于缓解交通拥堵的交通流预测方法研究逐渐重视.本文对厦门市城市道路的RFID(Radio frequency identification)数据预处理后进行相似性分析,选取相似性系数和不稳定系数为指标来表征路段交通流的相似度,并判断阈值以及对应交通状态下的路段交通转移量,最终以数据相似性为基础,建立交通流预测模型.选取10条城市道路RFID数据验证,其平均绝对误差为0.061,证明本文提出模型的可行性.
文摘Background Magnetic resonance spectroscopy （MRS） is one method that can examine noninvasively the alive specimen of the organ, metabolism of the organ and cell, and the biochemistry change. MRS provides the biochemistry information that may be used to diagnose tumors or differentiate the malignant tumor from benign. The objective of this study is to investigate the benign and malignant bone and soft tissue tumors by 1H-MR spectroscopy （^1H-MRS） on a 3 Tesla MR scanner, then to assess the usefulness of ^1H-MRS in diagnosing bone and soft tissue tumors and distinguishing benign from malignant tumors.Methods Fifty-six patients with bone and soft tissue tumors proved clinically and pathologically were examined with ^1H-MRS. ^1H-MRS was performed to study malignant musculoskeletal tumors, benign tumors and normal muscle adjacent to lesions to analyze the characteristics, and single-voxel point-resolved spectroscopy sequence was used. Proton brain exam-single voxel of ^1H-MRS which directly appeared in the spectrum, was observed to find the peak height of choline compounds （Cho） opposite to the creatine （Cr）, and whether there was a Cho peak. Metabolite values were calculated automatically from the area under each metabolite peak by the Functool 3.1 software. Metabolite ratios of Cho/Cr were manually calculated. Then according to the results, it was judged whether there existed benign or malignant tumors. The Kappa statistical test was used to analyze the MRS results, the histopathology data and the surgical situation. Statistics processing was performed using the software packaqe SPSS11.5 for Windows.Results ^1H-MRS spectra style of bone and soft tissue tumors was different from that of normal muscle, and differences also existed between benign and malignant tumors. Choline level in malignant tumor was markedly higher than that in benign tumors. Cho/Cr in malignant tumor was higher than in benign tumor significantly （P〈0.05）. The true positive rate of bone and soft tissue between benign and malignant tumors was 34/36, the true negative rate was 15/18, the false positive rate was 3/18 and the false negative rate was 2/36. Therefore in the group, sensitivity of the ^1H-MRS was 94% （34/36）, specificity was 83% （15/18）, positive predictive value was 92% （34/37）, negative predictive value was 88% （15/17） and the accuracy rate was 91% （49/54）. The MRS results and the histopathology inspection conclusions had very good uniformity. The K value was 0.76±0.10 （P 〈0.01）.Conclusions The increase of Cho level measured by ^1H-MRS is related to the bone and soft tissue malignant tumor. Cho/Cr in malignant tumor was higher than in benign tumor, so they will play a vital role in the diagnosis and differential diagnosis of bone and soft tissue tumors.
