Dynamic changes of the ecological environment quality in a river basin: a case study of the main stream of Songhua river basin

This paper reports the investigation and analysis of the status and dynamic changes of ecological environment quality in the main stream of Songhua river basin. The evaluation index system was established and the eco-environment quality in the year of 2000 and 2008 was studied in depth. Based on our research, the trend of dynamic changes of the eco-environment quality and its origins have been further discussed: In the year of 2000, the range of evaluation index covered from 0.31 to 0.47. Harbin and Yichun was relatively better than the rest of study areas. In the year of 2008, except districts of Daqing and Qitaihe, the environmental quality of Songhua river basin has entirely improved, wherein the evaluation index of the eco-environment covered from 0.31 to 0.57. Particularly, the eco-environment quality of Hegang and Shuangyashan has obtained significant improvement, whereas the improvement of Jiamusi was not obvious. According to the evaluation results, the environmental quality in the study area has an upward trend with the average growth rate 0.13% per year.     

广州市疏浚淤泥固化技术与工艺探讨

就疏浚淤泥的固化处置方法进行了论述,并结合广州市疏浚淤泥固化处置项目,主要探讨了广州市疏浚淤泥固化技术原理、固化剂以及工艺和设备,并对淤泥固化技术工程应用和固化效果进行了研究.     

曲线坐标系下考虑植被影响的三维水沙数学模型

建立曲线坐标系下的三维水流泥沙湍流运动模型模拟弯曲渠道内布置水生植被后的水流结构和河床变形分布,计算了试验室60o弯道内流经植被的水流流速平面结构和断面分布以及不同植被布置情况对水流泥沙运动和床面变形的影响。数值结果较好地再现了试验规律。计算结果表明在弯道内布置植被会改变水流流速分布情况:植被覆盖区域的水流流速降低、弯道内二次流减弱和泥沙运动减弱,而非植被覆盖区域的水流流速增大、断面二次流依然存在且泥沙运动加剧。通过比较两种水生植被布置条件下的床面变形情况,发现合理布置植被可以减缓凹岸的泥沙侵蚀,但也会加剧凸岸的泥沙淤积。     

云南省干旱及演变趋势分析

在收集云南省历史旱情、灾情资料以及1949—2009年的旱灾统计资料的基础上,分析云南省干旱周期的年际变化规律,空间分布规律以及干旱演变趋势,提出工程和非工程的抗旱措施,为云南省的抗旱减灾、制定抗旱调度方案提供科学依据。     

验前信息在反舰导弹靶场试验中的应用研究

针对反舰导弹靶场试验时如何把验前积累大量的先验信息科学合理利用,根据反舰导弹不同种类的验前信息,确定其分布类型并采用参数和非参数检验方法进行相容性检验,使经过预处理的验前信息能够为试验所用,并通过实例验证了该方法的科学可行性。该方法对验前信息在反舰导弹靶场试验及结果评定中的应用具有一定意义。     

Skeleton-based intrinsic symmetry detection on point clouds

We present a skeleton-based algorithm for intrinsic symmetry detection on imperfect 3D point cloud data. The data imperfections such as noise and incompleteness make it difficult to reliably compute geodesic distances, which play essential roles in existing intrinsic symmetry detection algorithms. In this paper, we leverage recent advances in curve skeleton extraction from point clouds for symmetry detection. Our method exploits the properties of curve skeletons, such as homotopy to the input shape, approximate isometry-invariance, and skeleton-to-surface mapping, for the detection task. Starting from a curve skeleton extracted from an input point cloud, we first compute symmetry electors, each of which is composed of a set of skeleton node pairs pruned with a cascade of symmetry filters. The electors are used to vote for symmetric node pairs indicating the symmetry map on the skeleton. A symmetry correspondence matrix (SCM) is constructed for the input point cloud through transferring the symmetry map from skeleton to point cloud. The final symmetry regions on the point cloud are detected via spectral analysis over the SCM. Experiments on raw point clouds, captured by a 3D scanner or the Microsoft Kinect, demonstrate the robustness of our algorithm. We also apply our method to repair incomplete scans based on the detected intrinsic symmetries.     

On Detectability and Observability of Discrete‐Time Stochastic Markov Jump Systems with State‐Dependent Noise

This paper mainly studies the notions of detectability and observability for discrete‐time stochastic Markov jump systems with state‐dependent noise. Two concepts, called “W‐detectability” and “W‐observability,” for such systems are introduced, and are shown to coincide with the other concepts on detectability and observability reported recently in literature. Moreover, some criteria and interesting properties for both W‐detectability and W‐observability are obtained.     

An improved ant colony optimization for scheduling identical parallel batching machines with arbitrary job sizes

In this paper we consider the problem of scheduling parallel batching machines with jobs of arbitrary sizes. The machines have identical capacity of size and processing velocity. The jobs are processed in batches given that the total size of jobs in a batch cannot exceed the machine capacity. Once a batch starts processing, no interruption is allowed until all the jobs are completed. First we present a mixed integer programming model of the problem. We show the computational complexity of the problem and optimality properties. Then we propose a novel ant colony optimization method where the Metropolis Criterion is used to select the paths of ants to overcome the immature convergence. Finally, we generate different scales of instances to test the performance. The computational results show the effectiveness of the algorithm, especially for large-scale instances.     

Multiconsensus of second order multiagent systems with directed topologies

A novel multiconsensus problem is introduced in multiagent systems. The states of multiple agents in each subnetwork asymptotically converge to a consistent value with information exchanges among subnetworks. The multiconsensus problem of second order multiagent systems with directed topologies is studied. Three linear protocols are proposed to solve the multiconsensus problem. Necessary and sufficient conditions are derived based on matrix theory. Simulations are provided to demonstrate the effectiveness of the theoretical results.