关系数据库中MVD超图的讨论

本文提出了ＭＶＤ超图的概念，给出了正向ＭＶＤ超图、逆向ＭＶＤ超图的定义。深入讨论了逆向ＭＶＤ超图、逆向准路（结点）、可人发准路结点、不可分准路结点及最小不可分准路结点等。在此基础上，给出了求解最小不可分结点的闭包算法。     

Immuno-Expression of Endoglin and Smooth Muscle Actin in the Vessels of Brain Metastases. Is There a Rational for Anti-Angiogenic Therapy?

Despite ongoing clinical trials, the efficacy of anti-angiogenic drugs for the treatment of brain metastases (BM) is still questionable. The lower response rate to anti-angiogenic therapy in the presence of BM than in metastatic disease involving other sites suggests that BM may be insensitive to these drugs, although the biological reasons underlining this phenomenon are still to be clarified. With the aim of assessing whether the targets of anti-angiogenic therapies are actually present in BM, in the present study, we analyzed the microvessel density (MVD), a measure of neo-angiogenesis, and the vascular phenotype (mature vs. immature) in the tumor tissue of a series of BM derived from different primary tumors. By using immunohistochemistry against endoglin, a specific marker for newly formed vessels, we found that neo-angiogenesis widely varies in BM depending on the site of the primary tumor, as well as on its histotype. According to our results, BM from lung cancer displayed the highest MVD counts, while those from renal carcinoma had the lowest. Then, among BM from lung cancer, those from large cell and adenocarcinoma histotypes had significantly higher MVD counts than those originating from squamous cell carcinoma (p = 0.0043; p = 0.0063). Of note, MVD counts were inversely correlated with the maturation index of the endoglin-stained vessels, reflected by the coverage of smooth muscle actin (SMA) positive pericytes (r = −0.693; p < 0.0001). Accordingly, all the endoglin-positive vessels in BM from pulmonary squamous cell carcinoma and renal carcinoma, displayed a mature phenotype, while vessels with an immature phenotype were found in highly vascularized BM from pulmonary large cell and adenocarcinoma. The low MVD and mature phenotype observed in BM from some primary tumors may account for their low sensitivity to anti-angiogenic therapies. Although our findings need to be validated in correlative studies with a clinical response, this should be taken into account in therapeutic protocols in order to avoid the adverse effects of useless therapies.     

一种用于多视视频加深度联合编码的错误隐藏算法

ATM(AVC-based test model)测试模型实现了多视视频加深度(MVD)格式的联合编码,使得数据的压缩效率更高。然而,较高的压缩效率使得码流对传输错误非常敏感,极易产生错误扩散现象。针对ATM测试模型的编码顺序,提出一种用于MVD联合编码的错误隐藏算法。算法充分利用视点内、视点间及纹理视频与深度视频间的相关性,针对每个视点的不同特征提出了适应其视频特性的不同隐藏算法。实验表明,本文提出的算法可以在不增加算法复杂度的情况下,有效提高视频的主客观质量。     

COBie标准在建筑工程数字化交付中的应用

COBie标准作为从建设方向运维方交付数据的信息交换标准,近年来已经逐步成熟并得到软件厂商的广泛支持,在国外的工程项目中逐步进行实际应用。上海市的BIM标准也参考COBie标准提出了建设-运维信息交换模板。COBie标准是基于IFC的信息交换标准,即按照施工-运营阶段之间的信息交换需求(IDM),从IFC中抽取了一个子集(COBie MVD)。COBie在建筑工程数字化交付中的应用需要考虑业主需求的数据完备性,以及不同项目参与方的数据采集录入流程和不同业务环境下的软件支持。COBie标准的应用对于BIM建模、数据采集流程都有相应的要求,并且在IFC环境或者Revit等特定软件环境下有不同的应用流程。COBie使设施运维人员、使用者和业主可以更轻松地访问与设施空间、设备有关的数据和文档,将基于纸张的交付过程转换为基于BIM的数字化交付,具有广阔的推广应用前景。     

存在多值依赖(MVD)的XML文档的规范化

讨论了在XML文档中存在多值依赖的情况下,如何规范XML文档,从而使XML文档有更小的冗余,以及更新、删除、插入异常。并在此基础上提出了一个规范化算法,来规范存在多值依赖的XML文档。并给出了算法的说明。     

基于直方图平移的视频密文域大容量可逆信息隐藏

针对视频密文域可逆信息隐藏（RDH）嵌入容量不高的问题,提出一种基于直方图平移的视频密文域大容量可逆信息隐藏方案。首先,利用流密码算法对4×4亮度帧内预测模式和运动矢量差值（MVD）的符号位进行加密,形成视频密文域;其次,构造MVD的二维直方图,设计关于（0,0）对称的直方图平移算法;最后,在MVD密文域中进行直方图平移,实现可分离的视频密文域可逆信息隐藏。实验结果表明,与对比方案相比,所提方案的嵌入容量平均提升263.3%,加密视频的平均峰值信噪比（PSNR）最高不超过15.956 dB,含密的解密视频的平均PSNR均能达到30 dB以上。所提方案可以有效提升嵌入容量,适用于更多类型的视频序列。     

An ontology-based analysis of the industry foundation class schema for building information model exchanges

Robust knowledge sharing frameworks between different stakeholders in a building project is of high priority. Industry Foundation Classes (IFC) provides a rich schema for interoperability through object-based transactions. However, IFC lacks semantic clarity in mapping entities and relationships, resulting in multiple definitions to map the same information between different federated models. The objective of this research is to examine IFC from a perspective of an ontological framework, which can make the IFC definitions more formal, consistent and unambiguous. Different methods of ontological approaches to engineering knowledge are reviewed. Various issues such as the need for a logical framework, the current semantic approaches in the AEC/FM industry, and advantages of building an ontology structure are addressed. A comparative study of the ontology and segments of the existing IFC schema definition are performed. This exercise reveals the ambiguous nature of current IFC definitions and proposes reforms such that data exchanges would be more semantically robust. An ontology would structure the overall interoperability of BIM tools by providing a formal and consistent taxonomy and classification structure for extending IFC and for defining subsets as model view definitions (MVD).     

Depth Similarity Enhanced Image Summarization Algorithm for Hole-Filling in Depth Image-Based Rendering

In free viewpoint video （FVV） and 3DTV, the depth image-based rendering method has been put forward for rendering virtual view video based on multi-view video plus depth （MVD） format. However, the projection with slightly different perspective turns the covered background regions into hole regions in the rendered video. This paper presents a depth enhanced image summarization generation model for the hole-filling via exploiting the texture fidelity and the geometry consistency between the hole and the remaining nearby regions. The texture fidelity and the geometry consistency are enhanced by drawing texture details and pixel-wise depth information into the energy cost of similarity measure correspondingly. The proposed approach offers significant improvement in terms of 0.2dB PSNR gain, 0.06 SSIM gain and subjective quality enhancement for the hole-filling images in virtual viewpoint video.     

H.264视频完整性认证的水印算法

提出一种适用于H.264压缩标准的视频完整性认证水印算法,通过对运动矢量残差MVD分量进行调制嵌入水印.考虑到视频的运动性,将水印嵌入到绝对值较大的残差分量中,并且在调制过程中限制对宏块的选择条件,从而降低水印嵌入对视频质量的影响.实验结果表明,本算法能够对视频是否遭受篡改,即视频内容的完整与否进行认证,并且水印嵌入后对视频质量和码率仅有微弱的影响.     

多单元高压变频器中点漂移法分析

本文介绍了级联多单元高压变频器使用中点漂移法解决单元故障时提高输出电压的方法。分析了不同故章模式下的处理措施和该方法的优缺点。对比分析了对称切除方式的差别。