报告题目一：The Hiemstra-Jones Test Revisited

报告人：惠永昌博士

报告时间：2017.07.06 14:40~15:30

报告地点：文科楼222

报告摘要：The famous Hiemstra-Jones (HJ) test developed by Hiemstra and Jones (1994) plays a significant role in studying nonlinear causality. In the last two decades there are numerous applications and theoretical extensionsbased on this pioneering work. However several works pointed out that counter-intuitive results are obtained from the HJtest and some researchers found that the HJ test is seriously over rejecting through simulation study. In this paper, we reinvestigateHJ's creative work in 1994 and found that their proposed estimators of the probabilities over different time intervals were not consistent to the target ones proposed in their criterion.To test the HJ's novel hypothesis on Granger causality, we shall propose new estimators of the probabilities defined in HJ's paper and reestablish the asymptoticproperties which will induce new tests similar to HJ's ones. Some simulation work will also be presented to support our new findings.

报告人简介：惠永昌，博士，西安交通大学副教授，硕士生导师，于2013年在东北师范大学获得博士学位，主持国家自然科学基金、中央高校基金等项目4项，作为研究骨干参与国家自然科学基金重大项目1项、面上项目2项，公开发表学术论文10余篇，其中在Journal of Financial Econometrics,Quantitative Finance等国际权威期刊上发表SCI检索论文7篇。曾先后于香港中文大学、香港浸会大学做研究助理工作；目前为西安交通大学统计系主任，主要从事时间序列、金融计量等方面的研究。

报告题目二：遥感图像的高光谱解混技术研究

报告人：刘军民博士

报告时间：2017.07.06 15:40~16:30

报告地点：文科楼222

报告摘要:高光谱遥感是一种信息获取与分析的高科技探测技术。它利用成像光谱仪，在电磁波谱的紫外、可见光、近红外等区域，获取许多非常窄且光谱连续的图像数据，即：高光谱图像。高光谱图像不仅具有遥感技术探测范围大、受地面条件限制少、信息量大的优点，而且克服了多光谱遥感技术在波段数、波段范围、精细信息表达等方面的局限性。但是，由于传感器空间分辨率的限制和地物的复杂多样性，混合像元普遍存在于高光谱图像中。混合像元的普遍存在严重阻碍了高光谱图像在现实中的应用。高光谱解混技术是处理混合像元问题的主要手段之一。本报告介绍高光谱遥感的应用背景、高光谱解混问题，并从凸面几何、统计推断、稀疏回归等方面出发讲述一些相关的处理方法和技术，最后对相关研究方向进行展望。

报告人简介：刘军民，博士，西安交通大学副教授，硕士生导师。分别于2006年和2009年在宁夏大学数学计算机学院获得学士和硕士学位，2013年在西安交通大学获得博士学位；于2011/09-2012/04在香港中文大学地理资源管理系做研究助理工作，于2014/09-2015/09在美国马里兰大学College Park分校从事访问研究； 于2013/07-2017/04在西安交通大学电信学院计算机科学系从事博士后工作研究。目前主要从事数据挖掘、机器学习、智能计算方法及其在遥感图像处理、人脸、手写体数字识别、图像分类等方面的基础理论与应用研究。截止2016年6月，在国内外学术期刊上发表论文20余篇，其中SCI检索16篇，IEEE系列期刊6篇；主持和参加国家自然科学基金973项目，面上项目，青年项目，博士后项目等十余项；担任IEEE TIP， IEEE TSP， IEEE TGRS，IEEE NNLS，IEEE SPL，IEEE GRSL，IEEE JSTARS，IJRS，Neural Networks等十余个国际权威期刊的审稿工作；曾获教育部博士研究生学术新人奖、首届“徐宗本应用数学论文奖”等奖励；研究成果谷歌学术引用280余次，其中单篇英文最高引用40次。

报告题目三：Adaptive Mixed-Hybrid and Penalty Discontinuous Galerkin method for two-phase flow in heterogeneous media

报告人：陈洁博士

报告时间：2017.07.06 16:40~17:30

报告地点：文科楼222

报告摘要:In this talk, we present a hybrid method, which consists of a mixed-hybrid finite element (MHFE) method with BDM1 space and a penalty discontinuous Galerkin (PDG) method, for the approximation of a fractional flow formulation of a two-phase flow problem in heterogeneous media with discontinuous capillary pressure. The fractional flow formulation is comprised of a wetting phase pressure equation and a wetting phase saturation equation which are coupled through a total velocity and the saturation affected coefficients. For the wetting phase pressure equation, the continuous MHFE method with BDM1 can be utilized due to a fundamental property that the wetting phase is continuous. While it can reduce the computational cost by using less degrees of freedom and avoiding the post-processing of velocity reconstruction, this method can also keep several good properties of the discontinuous Galerkin (DG) method, which are important to the fractional flow formulation, such as the local mass balance, continuous normal flux and capability of handling the discontinuous capillary pressure. For the wetting phase saturation equation, the PDG method is utilized due to its capability of handling the discontinuous jump of the wetting phase saturation. Furthermore, an adaptive algorithm for the hybrid method together with the centroidal Voronoi Delaunay triangulation (CVDT) technique is proposed. Four two dimensional numerical examples are presented to illustrate the features of proposed numerical method, such as the optimal convergence order, the accurate and efficient velocity approximation, and the applicability to the simulation of water flooding in oil field and the oil-trapping or barrier effect phenomena.

报告人简介：陈洁，博士，西安交通大学副教授，硕士生导师，分别于2004年和2007年在南京大学数学系获得学士和硕士学位，2011年在南洋理工大学获得博士学位；于2011/08-2012/10在香港科技大学做博士后研究，于2012/11-2013/03在阿普杜拉国王大学做博士后研究；2013/04进入西安交通大学数学与统计学院工作。研究方向是计算流体力学,油藏模拟。在Mathematics of Computation, Journal of computational physics, International Journal for Numerical Methods in Engineering等国际知名SCI期刊上发表论文十余篇，主持青年基金、博士后特等资助、CMG基金等7项科研项目，总金额160余万元。