基于局部熵的Active Demons多模医学图像配准

针对Active Demons算法只能配准同模态图像,并且图像的灰度梯度不太明显时形变方向无法确定从而导致误配准的问题,提出了一种基于局部熵改进的Active Demons多模医学图像配准算法.该算法首先将原图像转换为局部熵图像,然后使用改进的Active Demons算法进行配准,该算法在Active Demons分母上分别加入浮动图像与参考图像的灰度梯度值平方.正则化变换时以双边滤波器代替高斯滤波器,使得图像边缘的细节信息保持较好.多模态医学图像配准的实验结果说明该方法精确度高,使图像质量得以提升.     

一种基于DCWPSO算法与FFD模型的心脏CT序列图像配准算法

为实现心脏CT图像不同序列间的自动配准,提出了综合动态调整惯性因子权重的粒子群算法(DCWPSO)和自由形变(FFD)模型的非刚体医学图像配准方法.在对比常用的单纯形算法和模拟退火(SA)算法的基础上,采用动态调整惯性因子权重的自适应粒子群算法求解全局配准参数,克服了基于梯度的优化方法耗费时间长的缺点.在全局配准的基础上以FFD模型的形式应用层次B样条进行非刚性局部配准,利用B样条层次加细策略提高了配准的精度.实验结果表明,所提方法能够得到更好的配准结果.     

基于多幅图像恢复单幅图像的快速算法实现

为解决传统的单幅图像恢复算法效果不理想的情况,现有理论利用多幅图像之间的信息互补这一条件,在图像配准的基础上,通过多幅退化图像对单幅图像进行恢复,比较流行的是使用M估计(M-estimation)对图像进行配准,然后利用L1范数进行图像融合,进而提升图像恢复的鲁棒性,但其收敛速度并不理想。为了实现算法的快速收敛,通过对下降算法的搜索梯度方向改善的探究,出了基于共轭梯度下降法(conjugate gradient descent, CGD)的图像恢复算法。在此基础上对CGD图像恢复算法进行改进,利用前后估计的值之间的差信息来优化迭代时的搜索方向,也就是在后面这次搜索梯度上面加前1次和前2次估计值的差,以此增大搜索梯度值,进一步缩短迭代到最小值的时间。仿真结果表明,所提出的改进算法比基于最速梯度下降法(batch gradient descent, BGD)的图像恢复算法的收敛速度更快。     

基于统计形变模型的多模医学图像非刚性配准方法研究

多模医学图像间可能存在复杂的非刚性形变,矫正这类形变需要采用具有较高自由度的非线性变换模型.直接求解非线性变换的高维参数,不仅会增加配准时间,而且也影响配准精度.为此,本文提出一种基于统计形变模型的配准算法,该算法利用统计形变模型对大量多模图像间的非刚性形变进行统计学习,利用由此建立的模型大幅减少变换模型的参数,达到提高图像配准效率和精度的目的.大量的实验结果表明：与基于传统自由形变模型的配准算法相比,本文提出的基于统计形变模型的配准算法其效率可以提高52%,同时目标配准误差平均减少0.503 2个像素.     

混合谱梯度方法及其在医学图像弹性配准中的应用

 大规模优化问题一直是理论研究领域的研究重点,求解无约束最优化问题的混合谱梯度方法将多元谱梯度方法和谱梯度方法有效地 结合在一起,综合了二者的优势,引入非单调线搜索后,形成了全局收敛的混合谱梯度算法,并用于医学图像弹性配准B样条参数 模型的求解。医学图像弹性配准是医学图像处理研究的热点和难点,其中的参数模型往往转化为无约束优化问题的求解,当参数数 目较大时传统的方法求解费时,而混合谱梯度算法较多地利用梯度信息,避免了梯度计算的浪费,与层次B样条结合可以极大地提 高参数配准的优化速度和精度,算法中的非单调线搜索还有助于避免局部最优。     

基于梯度信息和区域互信息的图像配准

针对红外图像和可见光图像的特性,提出了基于梯度信息和区域互信息的红外与可见光图像配准。为了提高配准的速度,采用分层配准方法:使用小波分解将原始图像分为两层,在小尺度层上使用梯度信息和PSO方法找到粗配准参数,大尺度层上使用区域互信息和Powell搜索。其中,Powell搜索的初始值为粗配准参数,最终实现红外图像和可见光图像的有效配准。仿真实验结果表明:该算法配准精度高、速度快、鲁棒性好。     

基于梯度互信息与均匀设计PSO的航拍图像配准

基于互信息的图像配准算法精度较高,且易于实现自动配准,适合于无人机航拍图像配准.但在利用粒子群算法搜索最佳配准参数时,随机分布的初始粒子群容易集中在参数空间的某一区域,使算法陷入局部极值而得不到准确的配准结果;针对这一问题,提出一种新的图像配准算法,算法采用均匀设计思想改进粒子群算法,使初始粒子群能够均匀分布在搜索空间中,从而获得最佳配准参数;同时采用梯度互信息作为相似性测度,降低算法陷入局部极值的可能性.实验表明,新的算法能够更快更优地得到理想的航拍图像配准结果,验证了算法的有效性.     

改进的人工鱼群算法和Powell法结合的医学图像配准

针对目前基于互信息图像配准的局部极值问题,提出了一种改进的人工鱼群算法和Powell算法结合的多分辨率医学图像配准算法.该算法采用新的相似性测度方法即归一化模糊加权互信息和归一化局部能量加权匹配度,利用多分辨率策略采用HPV插值,并采用改进的人工鱼群算法结合Powell算法完成医学图像的配准.采用改进的人工鱼群算法在图像的最低分辨率上进行全局优化,以全局最优值为初始值,结合Powell算法完成图像配准.这不仅基本解决了互信息函数和Powell算法的局部极值问题,还减少了数据的处理量,加快了配准速度.实验结果表明,文中算法与其他经典的配准算法相比,提高了配准的精确度和性能.     

基于Keren改进配准算法的IBP超分率重建

提出了一种基于Keren改进配准算法的迭代反投影(iterative back-projection,IBP)超分辨率重建算法.该算法克服了Keren迭代配准算法基于小角度旋转的局限,并在迭代运算过程中引入了权重因子和阈值.权重因子有效地控制了算法的收敛速度,提高算法的稳定性.阈值的引入使得算法效率更高,配准结果更加准确.通过Keren改进配准算法进行配准,再通过IBP算法对配准后图像序列进行超分辨率重建,仿真结果表明,基于Keren改进配准算法的IBP重建具有良好的超分辨率重建效果.     

fMRI时间序列图像的配准测度及其相关优化方法

随着脑功能成像技术的迅速发展，人们对fMRI时间序列图像的配准问题也越来越重视．通过配准测度的建立，图像的配准问题最终被归结为数学上的多参数优化问题．本文综述了目前较常用的配准方法，介绍了基于灰度值的图像配准的差值平方和测度与互信息、测度以及求解它们的优化方法：阻尼GaussNewton法、有记忆功能的模拟退火算法、改进的Powell算法和一类新的进化策略算法．这四种算法各有特点能有效地找到最佳配准参数，配准精度较高，且能收敛到全局最优点。     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

橡胶颗粒沥青混合料低温抗裂性试验研究

以AC-13级配为基础,将橡胶颗粒代替部分集料掺入混合料中,以低温弯曲试验为评价方法对不同橡胶颗粒掺量下沥青混合料的低温抗裂性进行研究,并引入应变能密度值对混合料的低温抗裂性进行综合评价.试验结果表明:橡胶颗粒沥青混合料试件的破坏微应变均超过2 300,满足冬寒区的技术指标;无论是否掺加橡胶颗粒,随着温度的下降,沥青混合料破坏时的最大弯拉强度增大,弯拉应变降低,劲度模量增大;弯曲应变能密度在胶粒掺量为1%左右时具有较大的弯曲应变能密度值,此时橡胶颗粒沥青混合料具有较好的低温抗裂性.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Quantitative trait loci （QTLs） for quality traits related to protein and starch in wheat

Quality traits in wheat （Triticum aestirum L.） were studied by quantitative trait locus （QTL） analysis in a recombinant inbred line （RIL） population, a set of 131 lines derived from Chuan 35050 × Shannong 483 cross （ChSh）. Grains from RILs were assayed for 21 quality traits related to protein and starch. A total of 35 putative QTLs for 19 traits with a single QTL explaining 7.99-40.52% of phenotypic variations were detected on 10 chromosomes, 1D, 2A, 2D, 3B, 3D, 5A, 6A, 6B, 6D, and 7B. The additive effects of 30 QTLs were positive, contributed by Chuan 35050, the remaining 5 QTLs were negative with the additive effect contributed by Shannong 483. For protein traits, 15 QTLs were obtained and most of them were located on chromosomes 1 D, 3B and 6D, while 20 QTLs for starch traits were detected and most of them were located on chromosomes 3D, 6B and 7B. Only 7 QTLs for protein and starch traits were co-located in three regions on chromosomes 1D, 2A and 2D. These protein and starch trait QTLs showed a distinct distribution pattern in certain regions and chromosomes. Twenty-two QTLs were clustered in 6 regions of 5 chromosomes. Two QTL clusters for protein traits were located on chromosomes 1D and 3B, respectively, three clusters for starch traits on chromosomes 3D, 6B and 7B, and one cluster including protein and starch traits on chromosome 1D.