土壤水分自动观测数据质量控制与评估系统阈值研究方法

详细介绍了自动土壤水分数据质量控制系统中阈值的确定方法,通过对河南省历年人工观测的不同地域不同深度土壤水分数据的统计分析,结合河南省布设的GStarDNZ型土壤水分观测仪业务运行后的数据极值情况确定了各站点各层土壤水分数据的阈值。自动土壤水分数据智能评判软件采用有效的阈值,不仅可以对土壤水分观测仪器的运行状态进行监控,而且大大提高了土壤水分数据的可信度。     

Queueing model based resource optimization for multimedia cloud

Multimedia cloud is a specific cloud computing paradigm, focusing on how cloud can effectively support multimedia services. For multimedia service providers (MSP), there are two fundamental concerns: the quality of service (QoS) and the resource cost. In this paper, we investigate these two fundamental concerns with queueing theory and optimization methods. We introduce a queueing model to characterize the service process in multimedia cloud. Based on the proposed queueing model, we study resource allocation problems in three different scenarios: single-service scenario, multi-service scenario, and priority-service scenario. In each scenario, we formulate and solve the response time minimization problem and the resource cost minimization problem, respectively. We conduct extensive simulations with practical parameters of Windows Azure. Simulation results demonstrate that the proposed resource allocation schemes can optimally allocate cloud resources for each service to achieve the minimal response time under a certain budget or guarantee the QoS provisioning at the minimal resource cost.     

Brain MR image segmentation based on local Gaussian mixture model and nonlocal spatial regularization

Brain Magnetic Resonance (MR) images often suffer from the inhomogeneous intensities caused by the bias field and heavy noise. The most widely used image segmentation algorithms, which typically rely on the homogeneity of image intensities in different regions, often fail to provide accurate segmentation results due to the existence of bias field and heavy noise. This paper proposes a novel variational approach for brain image segmentation with simultaneous bias correction. We define an energy functional with a local data fitting term and a nonlocal spatial regularization term. The local data fitting term is based on the idea of local Gaussian mixture model (LGMM), which locally models the distribution of each tissue by a linear combination of Gaussian function. By the LGMM, the bias field function in an additive form is embedded to the energy functional, which is helpful for eliminating the influence of the intensity inhomogeneity. For reducing the influence of noise and getting a smooth segmentation, the nonlocal spatial regularization is drawn upon, which is good at preserving fine structures in brain images. Experiments performed on simulated as well as real MR brain data and comparisons with other related methods are given to demonstrate the effectiveness of the proposed method.     

Content-based image retrieval using H.264 intra coding features

Efficient multimedia retrieval has become a vital issue because more audio and video data are now available. This paper focuses on content-based image retrieval (CBIR) in the compression domain (CPD). The retrieval features are extracted based on I-frame coding information in H.264. This paper proposes using a local mode histogram as the texture feature to match images and applying the residual coefficients to filter non-confident modes. The geometrical correspondence between two images is also considered. The experimental results show that the proposed method can substantially reduce computational and memory resource consumption, and provides similar performance compared with methods that extract features from decompressed images.     

基于粒形分析的再生细骨料颗粒特性和制备砂浆性能研究

运用数字图像技术分析再生细骨料的颗粒形貌参数,以此为基础对再生细骨料的堆积密度、吸水率、压碎值等颗粒特性开展研究,并对再生细骨料制备水泥砂浆的工作性能和力学性能进行了分析。实验结果表明,再生细骨料与同级配的标准砂和天然河砂相比,钝度、长宽比、坚固度和球度等指标均相对较低,压碎值和吸水率显著增加;使用再生细骨料制备水泥砂浆时,质量替代量达到30%时流动度明显下降,质量替代量达到40%时抗压强度和峰值应力显著下降。     

黄河下游游荡性河段清水下泄期河道断面形态的调整过程

为预测小浪底水库运用后下游河道断面形态调整趋势，以1960～1964年三门峡水库清水下泄期定位观测资料为基础，结合物理模型试验，研究了清水下泄过程中黄河下游游荡性典型河段河势变化趋势、河道横断面形态的调整过程及其模式。研究表明，若缺乏较完善的整治工程体系的约束，尽管在上游水库建成运用后的清水下泄初期，河势会趋于相对归顺，但冲刷后期将会出现明显的坐湾摆动现象，游荡性并不能改变；横断面调整过程的模式基本上为“下切+展宽—下切—下切+局部河段展宽”；为利于河槽形成窄深断面，上游水库下泄流量不宜过小且历时不能过长，同时，流量变幅不宜过大。     

黄河下游平滩河槽形态与水沙搭配之关系

概括总结了对黄河下游断面几何特征与水沙关系(断面河相关系)的研究现状,基于"记忆"效应提出了几何特征与前期水沙的公式,利用1969～1996年水沙资料以及1973～1996年花园口～利津河段统测断面资料进行了统计分析,建立了花园口～高村、高村～艾山、艾山～利津河段平滩几何特征与前期水沙参数的(沿程河相)关系,认为各河段断面平滩几何特征与前期(前4年)水沙搭配条件有关,前期冲淤对断面形态的影响可以通过水沙搭配来反映,边界条件对断面形态的影响可以通过水沙参数的指数来反映.     

植物甾醇油酸酯-虾青素复合脂质体的制备工艺优化

为了改善虾青素的水溶性和稳定性,探索植物甾醇酯用于构建负载虾青素脂质体的可行性,以大豆磷脂为主要膜材,采用薄膜-超声法制备植物甾醇油酸酯-虾青素复合脂质体(L-PA)。以包封率为评价指标,通过单因素试验和Box-Behnken响应面试验优化L-PA的制备工艺。结果表明：L-PA制备的最佳工艺条件为植物甾醇油酸酯与大豆磷脂质量比1∶10、磷酸盐缓冲液pH 7.4、超声时间4 min、吐温80与大豆磷脂质量比1∶2、有机相与水相体积比1∶4、虾青素与大豆磷脂质量比1∶50,在此条件下L-PA的包封率为95.24%。因此,植物甾醇油酸酯可用于构建负载虾青素的脂质体。     

Projection based statistical feature extraction with multispectral images and its applications on the Yellow River mainstream line detection

Mainstream line is significant for the Yellow River situation forecasting and flood control. An effective statistical feature extraction method is proposed in this paper. In this method, a between-class scattering matrix based projection algorithm is performed to maximize between-class differences, obtaining effective component for classification; then high-order statistics are utilized as the features to describe the mainstream line in the principal component obtained. Experiments are performed to verify the applicability of the algorithm. The results both on synthesized and real scenes indicate that this approach could extract the mainstream line of the Yellow River automatically, and has a high precision in mainstream line detection. Communication author: Zhang Haichao, born in 1986, male, Ph.D. candidate.