Index Conditions of Resolution

In this paper, the following results are proved: (1) Using both deletion strategy and lock strategy, resolution is complete for a clause set where literals with the same predicate or proposition symbol have the same index. (2) Using deletion strategy, both positive unit lock resolution and input lock resolution are complete for a Horn set where the indexes of positive literals are greater than those of negative literals. (3) Using deletion strategy, input half-lock resolution is complete for a Horn set. Keywords Resolution - index strategy - deletion strategy - unit resolution - input resolution Xiaochun Cheng had his Ph.D in 1996. He has been working as a lecturer at The University of Reading since 2000. He is a guest professor at North East Normal University and at Beijing Normal University. His research interests include theoretical and applied aspects on decision support systems, knowledge-based systems, intelligent systems.

Representation of the ENSO Combination Mode and its Asymmetric SST Response in Different Resolutions of HadGEM3

Previous studies have revealed a combination mode （C-mode） occurring in the Indo-Pacific region, arising from nonlinear interactions between ENSO and the western Pacific warm pool annual cycle. This paper evaluates the simulation of this C-mode and its asymmetric SST response in HadGEM3 and its resolution sensitivity using three sets of simulations at horizontal resolutions of N96, N216 and N512. The results show that HadGEM3 can capture well the spatial pattern of the C-mode associated surface wind anomalies, as well as the asymmetric response of SST in the tropical Pacific, but it strongly overestimates the explained variability of the C-mode compared to the ENSO mode. The model with the three resolutions is able to reproduce the distinct spectral peaks of the C-mode at the near annual combination frequencies, but the performance in simulating the longer periods is not satisfactory, presumably due to the unrealistic simulation of the ENSO mode. Increasing the horizontal resolution can improve the consistency between atmospheric and oceanic representations of the C-mode, but not necessarily enhance the accuracy of C-mode simulation compared with observation.

Approximate Reasoning in Fuzzy Resolution

Resolution is an useful tool for mechanical theorem proving in modelling the refutation proof procedure, which is mostly used in constructing a “proof” of a “theorem”. An attempt is made to utilize approximate reasoning methodology in fuzzy resolution. Approximate reasoning is a methodology which can deduce a specific information from general knowledge and specific observation. It is dependent on the form of general knowledge and the corresponding deductive mechanism. In ordinary approximate reasoning, we derive from A→B and by some mechanism. In inverse approximate reasoning, we conclude from A→B and using an altogether different mechanism. An important observation is that similarity is inherent in fuzzy set theory. In approximate reasoning methodology-similarity relation is used in fuzzification while, similarity measure is used in fuzzy inference mechanism. This research proposes that similarity based approximate reasoning-modelling generalised modus ponens/generalised modus tollens—can be used to derive a resolution—like inference pattern in fuzzy logic. The proposal is well-illustrated with artificial examples.

The Systemic Immune Inflammatory Index Predicts No-Reflow Phenomenon after Primary Percutaneous Coronary Intervention in Older Patients with STEMI

Purpose:Coronary no-reflow phenomenon(NRP),a common adverse complication in patients with ST-segment eleva-tion myocardial infarction(STEMI)treated by percutaneous coronary intervention(PCI),is associated with poor patient prognosis.In this study,the correlation between the systemic immune-inflammation index(SII)and NRP in older patients with STEMI was studied,to provide a basis for early identification of high-risk patients and improve their prognosis.Materials and methods:Between January 2017 and June 2020,578 older patients with acute STEMI admitted to the Department of Cardiology of Hebei General Hospital for direct PCI treatment were selected for this retrospective study.Patients were divided into an NRP group and normal-flow group according to whether NRP occurred during the operation.Clinical data and the examination indexes of the two groups were collected.Logistic regression was used to analyze the independent predictors of NRP,and the receiver operating characteristic curve was used to further analyze the ability of SII to predict NRP in older patients with STEMI.Results:Multivariate logistic analysis indicated that hypertension(OR=2.048,95%CI:1.252–3.352,P=0.004),lymphocyte count(OR=0.571,95%CI:0.368–0.885,P=0.012),platelet count(OR=1.009,95%CI:1.005–1.013,P<0.001),hemoglobin(OR=1.015,95%CI:1.003–1.028,P=0.018),multivessel disease(OR=2.237,95%CI:1.407–3.558,P=0.001),and SII≥1814(OR=3.799,95%CI:2.190–6.593,P<0.001)were independent predictors of NRP after primary PCI in older patients with STEMI.Receiver operating characteristic curve analysis demonstrated that SII had a high predictive value for NRP(AUC=0.738;95%CI:0.686–0.790),with the best cut-off value of 1814,a sensitivity of 52.85%and a specificity of 85.71%.Conclusion:For older patients with STEMI undergoing primary PCI,SII is a valid predictor of NRP.

基于超分辨率重建与机器学习的油菜苗情监测方法

为优化养分管理和确保植株正常生长,以无人机遥感技术高效且非破坏采集田间作物苗情信息,监测油菜苗期的叶面积指数(LAI)与叶绿素相对含量(SPAD)。针对无人机因飞行高度与图像分辨率相互制约,监测效率与监测精度难以兼顾的问题,采用超分辨率重建方法,融合较低飞行高度拍摄高分辨率影像,重建较高飞行高度拍摄影像,建模完成后可通过拍摄飞行影像监测LAI和SPAD。试验设置3个氮肥梯度、3个播期、3个种植密度处理,在苗期利用无人机分别采集20m及40m 2个飞行高度的油菜苗影像,采用SRRestnet方法,对40m影像进行超分辨率重建。基于20m、40m及40m重建影像中提取的3种特征组合,利用偏最小二乘回归(PLSR)、随机森林(RF)、支持向量回归(SVR)3种机器学习方法对LAI和SPAD进行监测。结果表明,超分辨率重建后的图像在表型苗情监测中表现出良好效果,PLSR监测LAI、RF监测SPAD的监测精度最高,且40m重建图像的作业效率相比于20m图像提高48.6%。

重大突发事件下中国金融风险跨市场多周期溢出效应研究

在重大突发事件频发的背景下,从多周期角度考察中国金融风险的跨市场溢出效应,对于防范化解重大金融风险具有重要意义。采用小波多分辨分析、DY溢出指数与风险溢出网络模型,从静态和动态角度测度了重大突发事件的短期、中期、长期内我国金融市场间风险溢出的强度和方向,识别不同事件不同周期下的风险中心及演变规律。研究发现:从静态角度来看,中国金融市场平均风险溢出水平呈现随周期增加而增加的趋势,“欧债危机”时期的风险总溢出最小,市场在各个时期不同周期下的风险净溢出情况不同,净风险溢出、溢入市场不断变化;从动态角度来看,重大突发事件冲击下金融市场总体风险传染水平呈现先上升后逐渐平稳并回落的趋势,短期总溢出指数最低,中期最高,但在某些时期,短期总溢出水平可能高于中长期;不同重大突发事件、不同周期下风险的承担中心、风险在各金融市场间的传染路径均会发生变化。因此,在强化金融市场风险监管时,需要建立全流程风险防控体系以实现风险的有效处置,针对不同事件、不同周期的反应差异,实现金融风险的精准识别与重点管理。

2001—2020年渭北黄土台塬区农业干旱变化特征及影响因素分析

为明晰渭北黄土台塬区2001—2020年间农业干旱的时空变化特征及影响因素,利用MODIS遥感数据构建了Ts-NDVI特征空间,计算出温度植被干旱指数(TVDI),以揭示干旱的时空演变规律。同时,借助地理探测器分析了干旱与自然因素及人类活动之间的关联,确定了影响TVDI空间分异性的关键因子。结果表明:该区域平均每年有65.04%的区域遭受不同程度的干旱,多年平均TVDI值为0.52,整体处于中旱状态,且春季干旱尤为严重;2001—2020年,该区域TVDI值呈现波动下降趋势,并表现出强持续性特征,约有91.38%的区域干旱情况得到缓解或保持稳定;TVDI的空间分异性显著,主要受到高程、气温、人口密度和NDVI等多个因子的综合影响;在不同年份,影响TVDI的主导因子组合有所变化,这反映出自然因素和人类活动对干旱影响的复杂性。需综合运用气候监测、生态恢复、优化农业生产结构和提高水资源利用效率等措施,以更精准地预测和缓解干旱对区域农业生产和社会经济的影响。

基于管制指令的飞行冲突调配评估方法的研究

通过分析飞行冲突的预测与调配过程,根据飞行计划内的航迹和按调配规则调配后的航迹的对比明确飞行冲突危险指数概念,以此构建以有效性、准确性和及时性三个指标为基准的飞行冲突调配评估指标体系和评估指标的计算过程。飞行冲突评估指标体系及对比分析方法对飞行冲突的调配过程进行了量化,提高了决策结果的可信度,实现了在飞行冲突调配过程中对管制指令的分析。

基于IGGⅢ抗差估计的GNSS部分模糊度固定改进算法

针对滑坡等复杂环境下GNSS观测数据受高遮挡、多路径等因素影响,易使模糊度固定成功率降低进而导致定位可靠性变差的问题,提出一种基于IGGⅢ抗差估计的GNSS部分模糊度固定改进算法。通过引入抗差估计算法,削弱粗差对参数估计的影响,提升浮点模糊度精度;此外,为避免残余误差对后续整周模糊度解算产生影响,采用基于条件方差矩阵法的部分模糊度固定改进策略,进一步提升模糊度固定成功率。实验结果表明,相比于全模糊度固定方法,该算法可显著提高模糊度固定率,3个测站分别提升5.9%、52.7%、48.0%;同时,相比于传统的卡尔曼滤波算法,改进的抗差估计算法可明显改善模糊度固定错误的情况,极大提升GNSS定位精度,水平方向RMS优于1cm,高程方向RMS优于2cm。

2000—2020年“一江两河”地区耕地集约利用变化

耕地利用集约度是提高粮食产量、缓解人地矛盾,实现农业可持续发展的重要保障。本文基于高空间分辨率遥感影像获取的耕地数据,采用综合指标评价模型,探究了2000—2020年“一江两河”地区耕地的集约利用变化及驱动机制。结果表明:(1)近20 a来“一江两河”地区耕地利用集约度有所提升,但总体水平偏低。2020年耕地利用集约度较2000年提高了38.2%,这一提升主要归因于农资投入、技术投入和开发利用水平的增加。(2)各区县间耕地利用集约度变化差异大,在空间上呈现出高集约度区域由东部向西部迁移且范围扩大的变化特征,东西区域间耕地利用集约度差异缩小,低集约度的区县数量减少。(3)灌溉指数、耕地面积比重和耕地质量对“一江两河”耕地利用集约度的独立影响最显著,社会经济因素、农业科技因素和政策环境因素与耕地资源禀赋交互作用下对耕地利用集约度的影响程度增大。基于上述结果,提出以下政策建议:应持续推进“一江两河”地区农业科技创新,重点关注区域差异,实现高集约度地区可持续发展,低集约度地区全要素投入,同时充分发挥农业政策和经济的协同作用,协调促进“一江两河”地区耕地利用集约度提升。

基于不同流向算法的地形湿度指数模型差异性分析

土壤侵蚀是全球性的主要环境问题之一,不但会导致土壤退化、土地生产力降低和耕地面积减少,直接影响农业生产的食品安全,而且随径流泥沙转移对异地生态环境带来严重的影响。文章选取冬季云南元谋秃秃脊梁子地区的侵蚀沟区作为研究对象,基于高精度无人机航摄所得的数字高程模型(DEM),利用4种流向算法(Rho8、D8、Dinf和MFD-md)得到地形湿度指数(TWI)在3种分辨率下的运算结果,分析不同流向算法的地形湿度指数模型的差异性。研究结果表明:不同流向算法的差异主要集中在侵蚀沟坡面细沟区域;单流向算法可以有效展示沟道坡面细沟,多流向算法可以展示研究区整体汇水趋势;分辨率越高,算法的差异会越明显。文章进一步指出地形湿度指数对流向算法、DEM分辨率参数具有强烈的依赖性。

高分辨率遥感影像在违法用地检测中的应用方法研究

针对目前高分辨率遥感影像变化检测中存在的问题,本文提出了一种基于地物分布特征的违法用地变化检测方法。为了提高违法用地检测精度与稳健性,在变化检测模型中加入违法用地判别特征知识,针对不同的影像光谱-空间特征区域使用不同的变化检测方法。选择杭州市某地两组高分辨率遥感影像进行试验,结果表明相比于其他两种方法,本文方法在违法用地检测中的精度更高,能够快速实现疑似违法用地图斑的定位,将本文方法作为违法用地相关类变化检测作业的辅助可有效降低人工工作量,提高作业效率。

Dynamic Drought Monitoring in Guangxi Using Revised Temperature Vegetation Dryness Index

Moderate resolution imaging spectroradiometer （MODIS） data are very suitable for vast extent, long term and dynamic drought monitoring for its high temporal resolution, high spectral resolution and moderate spatial resolution. The composite Enhanced Vegetation Index （EVI） and composite land surface temperature （Ts） obtained from MODIS data MOD11A2 and MOD13A2 were used to construct the EVI-Ts space. And Temperature Vegetation Dryness Index （TVDI） was calculated to evaluate the agriculture drought in Guangxi province, China in October of 2006. The results showed that the drought area in Guangxi was evidently increasing and continuously deteriorating from the middle of September to the middle of November. The TVDI, coming from the EVI-Ts space, could effectively indicate the spatial distribution and temporal evolution of drought, so that it could provide a strong technical support for the forecasting agricultural drought in south China.

Development of a large-scale remote sensing ecological index in arid areas and its application in the Aral Sea Basin

The Aral Sea Basin in Central Asia is an important geographical environment unit in the center of Eurasia.It is of great significance to the ecological protection and sustainable development of Central Asia to carry out dynamic monitoring and effective evaluation of the eco-environmental quality of the Aral Sea Basin.In this study,the arid remote sensing ecological index(ARSEI)for large-scale arid areas was developed,which coupled the information of the greenness index,the salinity index,the humidity index,the heat index,and the land degradation index of arid areas.The ARSEI was used to monitor and evaluate the eco-environmental quality of the Aral Sea Basin from 2000 to 2019.The results show that the greenness index,the humidity index and the land degradation index had a positive impact on the quality of the ecological environment in the Aral Sea Basin,while the salinity index and the heat index exerted a negative impact on the quality of the ecological environment.The eco-environmental quality of the Aral Sea Basin demonstrated a trend of initial improvement,followed by deterioration,and finally further improvement.The spatial variation of these changes was significant.From 2000 to 2019,grassland and wasteland(saline alkali land and sandy land)in the central and western parts of the basin had the worst ecological environment quality.The areas with poor ecological environment quality are mainly distributed in rivers,wetlands,and cultivated land around lakes.During the period from 2000 to 2019,except for the surrounding areas of the Aral Sea,the ecological environment quality in other areas of the Aral Sea Basin has been improved in general.The correlation coefficients between the change in the eco-environmental quality and the heat index and between the change in the eco-environmental quality and the humidity index were–0.593 and 0.524,respectively.Climate conditions and human activities have led to different combinations of heat and humidity changes in the eco-environmental quality of the Aral Sea Basin.However,human activities had a greater impact.The ARSEI can quantitatively and intuitively reflect the scale and causes of large-scale and long-time period changes of the eco-environmental quality in arid areas;it is very suitable for the study of the eco-environmental quality in arid areas.

Numerical Modelling of the Topographic Wetness Index: An Analysis at Different Scales

A variety of landscape properties have been modeled successfully using topographic indices such as topographic wetness index (TWI), defined as ln(a/tanβ), where a is the specific upslope area and β is the surface slope. In this study, 25 m spatial resolution from digital elevation models (DEM) data were used to investigate the scale-dependency of TWI values when converting DEMs to 50 and 100 m. To investigate the impact of different spatial resolution, the two lower resolution DEMs were interpolated to the original 25 m grid size. In addition, to compare different flow-direction algorithms, a second objective was to evaluate differences in spatial patterns. Thus the values of TWI were compared in two different ways: 1) distribution functions and their statistics;and 2) cell by cell comparison of DEMs with the same spatial resolution but different flow- directions. As in previous TWI studies, the computed specific upstream is smaller, on average, at higher resolution. TWI variation decreased with increasing grid size. A cell by cell comparison of the TWI values of the 50 and 100 m DEMs showed a low correlation with the TWI based on the 25 m DEM. The results showed significant differences between different flow-diretction algorithms computed for DEMs with 25, 50 and 100 m spatial resolution.

基于深度学习的图像超分辨率研究综述

超分辨率(SR)是一类重要的数字图像处理技术,其根据一个观测者得到的低分辨率(LR)图像重建并输出一个相应的高分辨率(HR)图像,从而提高现代数字图像的分辨率。SR在数字图像压缩与传输、医学成像、遥感成像、视频感知与监控等学科中的研究与应用价值巨大。随着深度学习的快速发展,结合最新的深度学习方法,可以为SR问题提供创新性的解决方案。首先回顾SR的背景意义、发展过程以及将深度学习应用于SR的技术价值。其次简要介绍传统SR算法的基本方法、分类和优缺点;按照不同的实现技术和网络类型对基于深度学习的SR方法进行了分类介绍,重点分析对比了卷积神经网络(CNN)、残差网络(ResNet)和生成对抗网络(GAN)在SR中的应用。然后介绍主要评价指标和解决策略,并对不同的SR算法在标准数据集中的性能表现进行对比。最后总结基于深度学习的SR算法,并对未来发展趋势进行展望。

梯田对侵蚀地形指标的影响——以黄土丘陵第2副区为例

[目的]探究人工地形(梯田)对地形指标的影响,分析修建梯田对土壤侵蚀过程的影响,为土壤侵蚀评价中梯田措施因子的确定提供科学依据。[方法]通过无人机航空摄影测量,获取纸坊沟流域高精度DEM数据,通过模拟原始坡面数据和构建水平梯田数据,并对这些数据提取坡度、坡长、坡度坡长因子、单位汇水面积和地形湿度指数,分析了这些因子的变化情况,认识梯田对侵蚀地形的影响。[结果](1)梯田的修建使得坡度减缓、坡长截断、LS因子变小,随着梯田面积占比的增加,坡度、坡长、LS因子均呈减小趋势;梯田区,坡度、坡长、LS因子大致沿等高线呈条带状分布,非梯田区,坡度、坡长、LS因子从分水线向下逐渐增加,到沟底又逐渐变缓。(2)梯田的修建使得单位汇水面积减小、地形湿度指数变大;单位汇水面积的空间格局与坡长比较类似,较高部位单位汇水面积较小、低洼部位较大;梯田区地形湿度指数与坡度有相反的空间分布格局,非梯田区地形湿度指数与单位汇水面积类似。(3)微观尺度上,坡长、LS因子、单位汇水面积以及地形湿度指数均沿田面坡降方向呈增加趋势,在修建梯田或维护梯田时,应尽量保持田面水平或有微小反坡。(4)根据梯田对LS因子的影响,研究区梯田的工程措施因子值可取0.26~0.37。[结论]修建梯田对黄土高原丘陵地区水土保持有较大贡献,可为黄土高原丘陵区修建梯田和土壤侵蚀评价提供参考。

基于高分辨率遥感的耕地质量指标与评价进展

耕地质量作为反映耕地不同性状的综合性指标,对农业可持续发展有重要意义,文章综述了高分辨率遥感数据在耕地质量评价中的应用情况。当前耕地质量评价信息采集技术中存在监测范围小、监测时间跨度短、成本高、效率较低等问题,难以实现耕地质量的快速、准确评价。高空间分辨率、高时间分辨率、高光谱分辨率的遥感影像为长时序、大范围的耕地质量评价提供了技术支撑和数据基础。文章总结了国内外应用高分辨率遥感数据对地形特征、田间基础设施、生物多样性、土壤性状、农田环境状况等指标识别方法。文章在介绍耕地质量等级评价方法基础上,归纳了植被指数协同评价法,结合主成分分析法提出了基于高分辨率遥感的耕地质量评价方法,探索基于高分辨率遥感的耕地质量评价指标获取方法和评价体系,以期为快速、准确耕地质量评价研究提供参考。

植被指数在北京城市园林绿化覆盖率提取中的应用

为快速准确地获取城市园林绿化覆盖率,以北京市西城区的陶然亭街道为对象,基于高分辨率遥感影像,探讨了多种植被指数在城市园林绿化覆盖率提取中的可行性。结果表明:随着遥感影像空间分辨率的提高,有助于减少可见光植被指数提取结果中的地物误分,但基于0.5 m与0.8 m空间分辨率遥感影像的可见光植被指数所提取的绿化覆盖率均与实际值相差较大,因此不建议将其应用于园林绿化覆盖率提取研究中。而基于0.8 m空间分辨率遥感影像的归一化植被指数的绿化覆盖率提取比较适用于内部建筑高度较低的区域,可作为园林绿化资源普查工作的重要参考。在此基础上,还应用归一化植被指数,获取到北京2019年北京城市核心区(东城区和西城区)的绿化覆盖率为23.82%。

利用0.5 m分辨率卫星数据提取深圳市内浅水水体

以国产高景卫星影像为数据源,选取了深圳市内海岸浅水区、水库浅水区作为研究对象,针对浅水区域因底质的影响使近岸水体与沿岸土沙光谱反射率较为接近,导致水体边界提取难度大、精度差的难题,利用改进的变异系数法筛选水体指数,再结合DEM数据修正水体边界线并去噪,较精确地获取了浅水区水体边界。结果表明,本文方法对0.5 m分辨率卫星影像上的海岸浅水区、水库浅水区判别的总体精度分别为98.57%、91.10%,浅水区域水体提取的精度和稳定性得到了明显提高。