采用组合增强的YOLOX-ViT协同识别温室内番茄花果

番茄花果的协同识别是温室生产管理调控的重要决策依据,针对温室番茄栽培密度大,植株遮挡、重叠等因素导致的现有识别算法精度不足问题,该研究提出一种基于级联深度学习的番茄花果协同识别方法,引入图像组合增强与前端ViT分类网络,以提高模型对于小目标与密集图像检测性能。同时,通过先分类识别、再进行目标检测的级联网络,解决了传统检测模型因为图像压缩而导致的小目标模糊、有效信息丢失问题。最后,引入了包括大果和串果在内的不同类型番茄品种数据集,验证了该方法的可行性与有效性。经测试,研究提出的目标检测模型的平均识别率均值（mean average precision,m AP）为92.30%,检测速度为28.46帧/s,其中对小花、成熟番茄和未成熟番茄识别平均准确率分别为87.92%、92.35%和96.62%。通过消融试验表明,与YOLOX、组合增强YOLOX相比,改进后的模型m AP提高了2.38～6.11个百分点,相比于现有YOLOV3、YOLOV4、YOLOV5主流检测模型,m AP提高了16.56～23.30个百分点。可视化结果表明,改进模型实现了对小目标的零漏检和对密集对象的无误检,从而达到...     

坝基防渗治理的多目标模糊决策方法

提出了污水库坝基防渗治理方案的模糊决策方法.从多目标系统模糊决策基本理论出发,根据酸性污水库坝防渗加固工程的要求,选择治理可靠性、安全性、工程投资、施工工期、施工难易程度以及对环境的影响等6个指标,建立了防渗加固方案优选的评价体系.根据工程评价特点,采用变异系数法和专家调查法相结合的方法确定评价指标的权重,构造出酸性污水库坝防渗加固方案优选的决策与评价模型.利用该模型对矿山酸性污水库坝的防渗加固方案进行多目标优选决策.所得结果与实际建设一致,表明了该方法的可行性和有效性.     

基于差分GPS技术的淤地坝泥沙淤积量估算

淤地坝是黄土高原水土流失治理中的一项重要措施。但是早期建设的淤地坝缺乏监测资料,对现已淤满坝地拦截泥沙量的估算成为当前研究中的一个难点问题。该文选取延安宝塔区羊圈沟小流域1979年修建的淤地坝为研究对象,采用高精度差分GPS技术,测量坝地淤积面平均高程和淤地面积,结合1977年1︰10 000地形图,建立高程—面积/淤积量曲线,得出羊圈沟淤地坝淤积泥沙方量为155 849.2 m3,并通过计算得到建坝至淤满期内（1979－2004年）年平均土壤侵蚀模数4 052.1 t·km-2·a-1,属于中度侵蚀。差分GPS技术的应用为准确估算淤地坝泥沙淤积量提供了技术支撑,可以弥补历史上侵蚀产沙数据,而且对定量评价水土流失及其治理效益提供了依据。     

梯级泵站供水系统水资源优化调度模型研究

采用系统分析理论 ,研究了梯级泵站供水系统的水资源优化调度问题 ,建立了具有提调水量和泄弃水量两个决策变量及多级泵站、多个水库、多个供水片的多目标水资源优化调度模型 ,给出了自优化模拟调度方法。经实例研究表明 ,模型是可行和实用的     

堤坝白蚁防治方法比较研究

我国堤坝白蚁防治,提出和使用过多种方法,该文对其中的５种方法加以比较,结果认为要彻底消灭堤坝白蚁,目前最有效的应是“三环节,八程序”的新技术。     

Implications of piscine predator control on the federally listed fountain darter

One strategy for protecting the federally listed fountain darter, Etheostoma fonticola (Jordan & Gilbert), during low flow conditions is the removal of piscine carnivores [in this case, largemouth bass, Micropterus salmoides (Lacepède)]. However, headwater spring communities of the Comal and San Marcos rivers include another potential predator [red swamp crayfish, Procambarus clarkii (Girard)]. Removal of piscine carnivores could produce cascading effects by increasing crayfish consumption of benthic fish. The purpose of this study was to evaluate if piscine carnivore removal will lessen predatory pressure or induce a trophic cascade with crayfish increasing and causing declines in fountain darter. The numbers of fountain darter consumed were quantified among three predator treatments (red swamp crayfish only, largemouth bass only and red swamp crayfish and largemouth bass combined) and vegetation treatments (vegetated and non‐vegetated) at three temperature regimes (18, 22, 27°C). Vegetation had no effect on fountain darter predation. Among temperature trials, largemouth bass only and red swamp crayfish and largemouth bass combined consumed similar numbers of fountain darter, and red swamp crayfish only consumed the least numbers of fountain darter, except at 22°C. Largemouth bass did not consume more red swamp crayfish than fountain darter. Therefore, largemouth bass removal appears to be a viable option for reducing fountain darter predation during periods of low flow.     

Worldwide status of burbot and conservation measures

Although burbot ( Lota lota Gadidae) are widespread and abundant throughout much of their natural range, there are many populations that have been extirpated, endangered or are in serious decline. Due in part to the species' lack of popularity as a game and commercial fish, few regions consider burbot in management plans. We review the worldwide population status of burbot and synthesize reasons why some burbot populations are endangered or declining, some burbot populations have recovered and some burbot populations do not recover despite management measures. Burbot have been extirpated in much of Western Europe and the United Kingdom and are threatened or endangered in much of North America and Eurasia. Pollution and habitat change, particularly the effects of dams, appear to be the main causes for declines in riverine burbot populations. Pollution and the adverse effects of invasive species appear to be the main reasons for declines in lacustrine populations. Warmer water temperatures, due either to discharge from dams or climate change, have been noted in declining burbot populations at the southern extent of their range. Currently, fishing pressure does not appear to be limiting burbot populations world-wide. We suggest mitigation measures for burbot population recovery, particularly those impacted by dams and invasive species.     

Shedding light on the migratory patterns of the Amazonian goliath catfish,Brachyplatystoma platynemum,using otolith 87Sr/86Sr analyses

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