测量噪声相关情况下的航迹融合和测量融合

研究了测量噪声相关情况下的航迹融合和测量融合问题,根据线性无偏最小方差估计理论,推导了噪声相关情况下的多传感器跟踪系统的航迹融合和测量融合算法.经Monte Carlo仿真表明,文中给出的考虑噪声相关的航迹融合和测量融合算法的跟踪精度均高于相应的不考虑噪声相关的传统算法,且附加的计算量很小.     

体外大鼠成骨细胞对破骨细胞形成的影响

目的通过将鼠成骨细胞与破骨细胞直接共培养的实验方法,研究成骨细胞对破骨细胞分化及功能成熟的影响。方法按照M-CSF 30μg/L、RANKL 50μg/L的浓度对鼠骨髓单个核细胞诱导培养6 d,与原代培养3 d的鼠成骨细胞按细胞数量1∶1直接共培养,加入1,25-(OH)2D31×10-8mol/L和PGE21×10-6mol/L,利用形态学观察、TRAP染色、骨吸收陷窝检测等方法对共培养细胞进行鉴定。结果成骨细胞与破骨细胞共培养时,成骨细胞有明显的生长优势;染色后显微镜下可见大量呈单层排列的成骨细胞,偶见TRAP( )的破骨细胞。结论成骨细胞对破骨细胞分化及功能成熟的影响与两者的相对数量有关。本实验中,由于成骨细胞快速生长,当其数量多于破骨细胞时,可能使1,25-(OH)2D3对成骨细胞RANKL表达的上调作用不足,且PGE2对成骨细胞OPG表达的下调作用不足,从而主要表现为对破骨细胞形成及分化的抑制作用。     

关于公路建设项目经济评价的几点思考

经济评价是通过财务评价和国民经济评价,分析项目的经济合理性和财务合理性,并作为项目是否建设的重要决定要素之一。交通量预测、评价指标的选取、征地补偿费用与土地机会成本、国民经济效益等计量的正确与否将直接影响项目经济评价的结果。     

城市道路交通拥挤识别方法研究

界定了交通拥挤的概念及属性,总结了交通拥挤的识别方法和流程,介绍了识别交通拥挤的主要算法和模型。     

数字图像技术在露石混凝土路面中的应用

应用数字图像技术,将普通数码相机拍摄的露石水泥混凝土路面照片进行处理,根据图像的灰度值变化分析得到露石混凝土路表面的构造深度,并通过与常规方法的比较表明,此方法测量的路表面构造深度结果可靠,操作简单,可以在分析露石混凝土路面粗糙的表面特征上应用。     

十堰汽配竞争策略分析

我国汽配产业整体竞争能力呈下滑趋势。面临很大的竞争压力。十堰作为我国汽配产业起步较早的城市,随着东风公司迁都武汉,以及其零部件全球采购策略的贯彻,使得十堰市零部件产业面临着转型。因此,提升十堰汽配的核心竞争力是下一步工作的重点。文章描述了我国汽配产业的现状,分析了十堰汽配的竞争能力,并提出了十堰汽配的竞争策略。     

A total generalized optimal velocity model and its numerical tests

A car-following model named total generalized optimal velocity model （TGOVM） was developed with a consideration of an arbitrary number of preceding vehicles before current one based on analyzing the previous models such as optimal velocity model （OVM）, generalized OVM （GOVM） and improved GOVM （IGOVM）. This model describes the physical phenomena of traffic flow more exactly and realistically than previous models. Also the performance of this model was checked out by simulating the acceleration and deceleration process for a small delay time. On a single circular lane, the evolution of the traffic congestion was studied for a different number of headways and relative velocities of the preceding vehicles being taken into account. The simulation results show that TGOVM is reasonable and correct.     

Energy-aware load-balaning fault-tolerant routing scheme for ad hoc sensor networks

Most routing protocols for sensor networks try to extend network lifetime by minimizing the energy consumption, but have not taken the network reliability into account. An energy-aware, load-balancing and fault-tolerant routing scheme, termed as ELFR was propsed to adapt to the harsh environment. First a network robustness model was presented. Based on this model, the route discovery phase was designed to make the sensors to construct into a hop-leveled network which is mesh structure. A cross-layer design was adopted to measure the transmission delay so as to detect the failed nodes. The routing scheme works with acknowledge （ACK） feedback mechanism to transfer control messages to avoid producing extra control overhead messages. When nodes fail, the new healthy paths will be selected locally without rerouting. Simulation results show that our scheme is much robust, and it achieves better energy efficiency, load balancing and maintains good end-to-end delay.     

Joint distortion model for progressive image transmission using error correcting arithmetic codes

A novel joint source channel distortion model was proposed, which can essentially estimate the average distortion in progressive image transmission. To improve the precision of the model, the redundancy generated by a forbidden symbol in the arithmetic codes is used to distinguish the quantization distortion and the channel distortion, all the coefficients from the first error one to the end of the sequence are set to be a value within the variance range of the coefficients instead of zero, then the error propagation coming from the entropy coding can be essentially estimated, which is disregarded in the most conventional joint source channel coding （JSCC） systems. The precision of the model in terms of average peak-signal-to-noise has been improved about 0.5 dB compared to classical works. An efficient unequal error protection system based on the model is developed, and can be used in the wireless communication systems.     

公交优先是上海城市交通发展战略的唯一选择

土地资源的紧张和环境保护的压力,是上海交通发展的瓶颈。解决上海交通发展瓶颈唯一正确的选择,就是全面实施“公交优先”的发展战略。具体措施包括以下方面。