一种基于学习的非线性人脸图像超分辨率算法

提出了一种单幅人脸图像的超分辨率重构算法。该算法采用马尔可夫网络模型描述重构机制,对输入的低分辨率图像,以及训练用高分辨率图像和对应的低分辨率图像进行分块,并使图像基本对齐,构造训练图像集。针对简化马尔可夫网络计算的需要以及训练集人脸图像的差异,在采用块坐标限位操作的基础上,使用了一种非线性样本搜索算法,降低了搜索空间复杂度,提高了匹配效率和相关性。算法利用搜索到的高分辨率图像分块样本,直接输出超分辨率图像。分析和实验表明,与传统学习算法相比,该方法具有输出质量好、效率高的特点。     

A signal theory approach to the space and frequency variant filtering performed by the human visual system

A mathematical representation is given of the processing performed by the peripheral nervous cells of the human visual system. This representation consists essentially of a set of shift-variant convolutions, implying non-uniform resolutions in both the space and frequency domains. A remarkable property of such “convolutions” is the form-invariance of their outputs with respect to (size) linear scalings of the inputs. It is shown that this latter property is a necessary support of the hypothesis according to which the visual system translates linear scalings of the (retinal) inputs into shifts of the (cortical) outputs.     

Proactive multipath routing with a predictive mechanism in software‐defined networks

With the growth of network traffic volume, link congestion cannot be avoided efficiently with conventional routing protocols. By utilizing the single shortest‐path routing algorithm from link state advertisement information, standard routing protocols lack of global awareness and are difficult to be modified in a traditional network environment. Recently, software‐defined network (SDN) provided innovative architecture for researchers to program their own network protocols. With SDN, we can divert heavy traffic to multiple paths in order to resolve link congestion. Furthermore, certain network traffics come in periodic fashion such as peak hours at working days so that we can leverage forecasting for resource management to improve its performance. In this paper, we propose a proactive multipath routing with a predictive mechanism (PMRP) to achieve high‐performance congestion resolution. PMRP has two main concepts: (a) a proactive mechanism where PMRP deploys M/M/1 queue and traffic statistics to simulate weighted delay for possible combinations of multipaths placement of all subnet pairs, and leverage genetic algorithm for accelerating selection of optimized solution, and (b) a predictive mechanism whereby PMRP uses exponential smoothing for demand traffic volumes and variance predictions. Experimental results show a 49% reduction in average delay as compared with single shortest routing, and a 16% reduction in average delay compared with utilization & topology‐aware multipath routing (UTAMP). With the predictive mechanism, PMRP can decrease an additional 20% average delay. Furthermore, PMRP reduces 93% of flow table usage on average as compared with UTAMP.     

叶绿素荧光量子产量的MODIS遥感算法

从荧光量子产量的原理出发,利用 MODIS 卫星数据建立了一种估算量子产量的算法--φ算法.通过 2006 年 3 月 23 日渤海和北黄海的 MODIS 数据计算了荧光量子产量,并与叶绿素荧光效率(cFE)产品进行了比较.结果表明,φ算法是一种更精确的荧光量子产量的估算算法,它有效地避免了 CFE 存在的几个误差来源:包括未考虑浮游植物的"包裹效应"、使用 412nm 的离水辐亮度反演的浮游植物吸收系数以及积分深度过浅.CFE在大部分海域出现负值,还出现了某些高估点;在有效数据范围内,两者存在明显的线性相关关系.φ算法估算的量子产量最高值在0.05左右,这与其它海区测量的值域范围基本一致.除辽东湾东北部和部分近岸水域外,大部分离岸水域在0.001～0.02的范围内.通过对φ算法的误差来源分析,认为发展一种新的反演 678nm 比吸收系数和平均吸收系数的波段比值算法是可行的,也是改进φ算法精度的有效方法.     

一种适用于集群无人机超分辨的波束域方位估计算法

为了提升对集群无人机目标的分辨能力,提出了一种波束域方位超分辨估计算法。该方法不仅可以避免传统的稀疏表示类测角方法的计算复杂度高和需要选取超参数问题,而且在单快拍数、入射信号空间角度间隔较小等非理想情况下都具备很好的分辨能力,与相控阵雷达波束形成、距离?多普勒域处理的流程相适配。通过仿真试验,可以说明：该方法可以帮助雷达提前将密集目标分辨开,进而实现对于集群的规模（个数）、轮廓等信息进行准确估计,具有很强的应用价值。     

基于Gabor变换的地震资料高分辨率处理方法研究

日益复杂的勘探目标对地震资料的分辨率提出了更高的要求,常规的反褶积和反Q滤波等高分辨率处理方法往往需要精确的先验信息,同时忽略了低频成分的补偿,不能满足实际生产需要。文中采用基于时频变换的高分辨率处理方法,在Gabor时频变换的基础上,引入倒频谱。利用倒频谱的思想,在时频域对振幅谱进行对数改造,保持相位谱不变,同时采用平滑处理以补偿低频成分,联合实现高分辨率处理。将该算法应用到雷克子波、薄层、楔形体模型以及实际地震数据中,结果显示子波持续时间减小,低于调谐厚度的薄层得到识别,频带拓宽,分辨率得到了提高,验证了该方法的有效性。最后,探究了时窗宽度对处理结果的影响,结果表明,为了达到更好的高分辨率处理效果,Gabor变换的高斯窗宽度应不低于子波的持续时间。     

Molecular Weight Measurement of UG8 Asphaltene Using APCI Mass Spectroscopy

Abstract

Asphaltene molecular weight has been a controversial issue in the past several decades and continues on nowadays. From industrial application point of view, asphaltene molecular weight is important for setting up a heavy oil refining strategy so that the process is efficient and economically viable. If the measured average molecular weight of asphaltene is high and is the true molecular weight, then substantial amount of energy will be needed, in order to break the molecule into light products during refining process. This is likely not an economical option. On the other, if the measured high molecular weight is due to self-association and the true molecular weight is low (e.g., less than 1500 Da), it will be energetically attractive to refiners to develop heavy oil cracking technology. Vapor pressure osmometry (VPO) has been routinely used for measuring molecular weight. However, it measures the apparent molecular weight and is likely not the true molecular weight. In order to unambiguously measure the molecular weight, it is necessary to develop a convincing technology and a reliable experimental procedure that allows one to measure the molecular weight accurately and consistently. We chose the Atmospheric Pressure Chemical Ionization (APCI) technique and Atmospheric Pressure Photo Ionization (APPI) to measure UG8 asphaltene. Both APCI and APPI have mild ionization processes and have been applied to many unstable drug compounds such as proteins and peptides with reliable outcomes. In addition, we measured the sample on two APPI instruments to compare the results. We also demonstrated how one can choose wrong set of operating parameters and lead to erroneous results. The relevant parameters for APCI and APPI are temperature, voltage, and sample concentration. We chose 0.01 mg/mL as the concentration, much below any known critical aggregation concentration. As for temperature and ionization voltage, we varied systematically varied (T = 300–600°C; V = 30–150 V) in order to demonstrate the consistency of the methods and how one can easily make mistake. Through these measurements, an average molecular weight of 400 to 900 Da was obtained for UG8 asphaltene.     

反舰导弹突击岛礁区舰船末制导雷达开机距离和角度研究

为从战术层面提高雷达制导反舰导弹导引头截获岛礁区舰船的能力,在分析雷达导引头截获岛礁区舰船必要条件的基础上,建立了导弹、目标舰船与岛礁的位置关系模型,推导得到末制导雷达开机距离、攻击方位同岛目距离差、角度差的关系表达式,为判断是否满足截获条件提供了依据,并进行了仿真分析.研究成果为优化雷达制导反舰导弹攻击岛礁区目标舰船的作战使用奠定了基础.     

扫描拉曼埃分辨显微术:一种新的分子化学结构解析方法

针尖增强拉曼光谱(TERS)技术由于其超高的空间分辨与灵敏的化学识别能力,在纳米尺度的结构表征和物理化学性质的分析中发挥着重要作用。本文首先回顾了高分辨TERS技术的近期发展与应用,并对高分辨成像的潜在物理机理进行了简要概述,接着介绍一种由超高分辨TERS成像衍生出来的新的分子化学结构解析方法―扫描拉曼埃分辨显微术(SRP),最后对SRP技术的进一步发展进行了展望。     

Simple method of calibration of conventional sodar antenna system

The accurate estimation of sodar antenna parameters, back-scattering cross-section and a knowledge of acoustic absorption in the atmospheric air are needed in case structure parameters are to be computed. In the paper a simple method using a theoretical antenna directivity pattern, together with measurements of transduction characteristics of the acoustic transducer has been suggested. The method has been used for two sodars belonging to the Russian Academy (Sodar Latan-I) and the National Physical Laboratory, New Delhi, The theoretically and experimentally determined directivities of the Sodar Transducer Systems have been compared and it has been found that they coincide rather satisfactorily within the angles at which the paraboloids of sodars are seen from their respective foci. Computed thermal structure parameter values using Sodar Latan-I based on the above approach have been found to be comparable with the values computed from microthermal data collected simulaneously at the same place