A Comparative Study of Various Supervised Learning Approaches to Selective Omission in a Road Network     

Qi Zhou  Zhilin Li 《The Cartographic journal》2017,54(3):254-264

Selective omission is necessary for road network generalisation. This study investigates the use of supervised learning approaches for selective omission in a road network. To be specific, at first, the properties to measure the importance of a road in the network are viewed as input attributes, and the decision of such a road is retained or not at a specific scale is viewed as an output class; then, a number of samples with known input and output are used to train a classifier; finally, this classifier can be used to determine whether other roads to be retained or not. In this study, a total of nine supervised learning approaches, i.e., ID3, C4·5, CRT, Random Tree, support vector machine (SVM), naive Bayes (NB), K-nearest neighbour (KNN), multilayer perception (MP) and binary logistic regression (BLR), are applied to three road networks for selective omission. The performances of these approaches are evaluated by both quantitative assessment and visual inception. Results show that: (1) in most cases, these approaches are effective and their classification accuracy is between 70% and 90%; (2) most of these approaches have similar performances, and they do not have any statistically significant difference; (3) but sometimes, ID3 and BLR performs significantly better than NB and SVM; NB and KNN perform significantly worse than MP, SVM and BLR.  相似文献   

中国对虾生物能量学研究Ⅰ——温度、体重、盐度和摄食状态对耗氧率和排氨率的影响   总被引：2，自引：0，他引：2  

张硕  董双林  王芳 《中国海洋大学学报(自然科学版)》1998,(2)

实验于１９９６年５月～９月对３种规格养殖中国对虾在不同条件下的耗氧率和排氨率进行了测定。结果表明,温度、体重、盐度和摄食状态对其代谢有显著影响。耗氧率（ＱＯ）和排氨率（ＱＮ）与温度正相关,ｌｎＱＯ＝０．０５８Ｔ－２．８９４;ｌｎＱＮ＝０．０７６Ｔ＋１．１１６;而与体重呈负相关,ＱＯ＝０．５１５Ｗ－０．１２６;ＱＮ＝２５．０５Ｗ－０．１９９。在盐度５～３５范围内,中国对虾（３．０２５ｇ±０．０８８ｇ）的耗氧率和排氨率在盐度２８时最小。中国对虾（３．１３ｇ±０．０７２ｇ）摄食沙蚕和配合饲料,在饱食状态下耗氧率比饥饿状态下分别提高了８３．９％和２９．３％,排泄率增加了１１３．８％和９３．６％,表明摄食时蛋白质代谢增加显著。  相似文献   

Movement and Home Ranges of Dugongs Around the Lease Islands, East Indonesia   总被引：1，自引：0，他引：1  

Hans H. de  Iongh  Paul  Langeveld Mark  van der Wal 《Marine Ecology》1998,19(3):179-193

Abstract. Four individual dugongs Dugong dugong , MÜLLER, 1776 were tracked with buoyant, tethered. conventional and satellite radio transmitters. The dugongs three adult females and one immature male were encircled with a net at a catch site near Haruku Island, East Indonesia, and tracked for between 41 and 285 days. The animals showed individualistic patterns of movement, moving between 2 and 3 core areas, travelling between 17 and 65 km from the site of capture. One adult female spent most of the time at two distinct inshore seagrass beds separated by about 17 km; she made five trips between the two sites. Two other females made separate trips to two distinct sites, one of them returning to the catch site at Haruku Island. The immature male journeyed between two areas about 65 km apart. completing the journey in four days. The patterns of movement confirmed a practice of regular recropping of restricted grazing swards by small, loose feeding assemblages rather than fixed herds with a strong social bond. Mean home ranges covered 4.1 km² 50% harmonic mean and 43.4 km² 95% harmonic mean.  相似文献   

The total‐to‐selective extinction ratio determined from near IR photometry of OB stars     

W. Wegner 《Astronomische Nachrichten》2003,324(3):219-237

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Effect of Copper on Activity and Feeding in the Subtidal Prosobranch Babylonia lutosa (Lamarck) (Gastropoda: Buccinidae)     

S. G. Cheung  L. S. Wong 《Marine pollution bulletin》1999,39(1-12):106-111

Individuals of the subtidal gastropod Babylonia lutosa were exposed to three sublethal concentrations of copper (0.02, 0.06 and 0.20 ppm) for four weeks. The percentage of normally active individuals (body extended and moving with the foot attached) decreased and the percentage of snails retracted (body extended, foot not attached, unable to move) and in a distressed stage (body retracted within the shell) increased with increase in copper concentration. Exposure to copper also decreased significantly the ability of an individual to move, and to burrow, but the effect was only observed in week 1, individuals were fully recovered in week 2. Feeding, however, was not affected, both in terms of the percentage number of individuals which fed, and the time spent feeding. Results were discussed with respect to the potential of using this animal as a bioassay tool in monitoring the effect of environmental perturbations on the subtidal community in Hong Kong.  相似文献   

南海西北部水域斑节对虾资源的调查研究   总被引：2，自引：0，他引：2  

钟振如  李辉权  张月平  陈敏 《热带海洋学报》1999,18(3):58

1989－1991年对南海西北部水域进行斑节对虾Penaeusmonodon资源专项调查。结果表明,斑节对虾的密集分布区在海南岛东部和南部海区,其现存资源量为82．6万尾,周年有体长30mm以下的幼虾出现。主要产卵期在9－12月。产卵场在海南岛东部和南部水深30-60m的海区。  相似文献   

Patterns of RNA/DNA ratios in larval fish and their relationship to survival in the field   总被引：1，自引：1，他引：0  

Pepin  P.; Evans  G. T.; Shears  T. H. 《ICES Journal of Marine Science》1999,56(5):697-706

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Growth histories derived from otolith microstructure of three Norwegian cod stocks co-reared in mesocosms; effect of initial size and prey size changes   总被引：2，自引：1，他引：1  

Suthers  I. M.; Van Der Meeren  T.; Jorstad  K. E. 《ICES Journal of Marine Science》1999,56(5):658-672

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水声学方法对黄河口水下底坡失稳现象研究     

阎通  李萍  杨作升  庞重光 《中国海洋大学学报(自然科学版)》1999,(2)

对黄河三角洲东北部地区的高分辨率水声学资料进行了综合研究。根据所记录的破坏土体变形程度、运动产生的平面形状和地貌特征形态,对土体失稳过程进行分类：浅表土体变形、塌陷凹坑、滑坡和沉积物重力流。结果表明：（１）浅表土体形变的变形程度最低,出现在研究区斜坡上部平滑海底,主要为绳网状泄水构造和表层拉张裂隙。（２）塌陷凹坑在研究区内广泛出现,是局部土体液化后发生了垂直沉降的结果。（３）滑坡多发生在水下斜坡的中上部,由弧形塌陷区、狭窄的冲沟通道和负地形沉积物堆积区组成。滑坡陡坎后缘发现拉张裂隙。（４）沉积物重力流是土体发生变形程度最大,搬运距离最长的土体破坏变形形式。局部区域多次受到沉积物重力流切割和充填作用。  相似文献   

Macroinvertebrate community structure and feeding interactions along a pollution gradient in Gilgel Gibe watershed,Ethiopia: Implications for biomonitoring     

《Limnologica》2017

Feeding interactions among functional feeding groups (FFGs) of macroinvertebrates are robust indicators of aquatic ecosystem interactions. They provide information regarding organic matter processing, habitat condition and trophic dynamics. In tropical rivers with pronounced wet and dry seasons, macroinvertebrate based ecological monitoring tools are explicitly focused on metrics and indices, while ignoring interactions of FFGs. Therefore, the objective of this study was to investigate the functional feeding type metrics, diversity indices and feeding interactions among FFGs of macroinvertebrates along the water pollution gradient in Gilgel Gibe watershed, Ethiopia. Water quality parameters and macroinvertebrate community attributes were assessed for samples collected from upstream sites (15 sites), urban-impacted stretches (12 sites) and wetland-affected river zones (7 sites) of the watershed during the rainy (July) and dry (February) seasons. To understand the effect of pollution on the feeding interactions, stable carbon and nitrogen isotopes were analyzed. Macroinvertebrate-based diversity indices and functional feeding type metric showed deterioration of ecological integrity at the urban-impacted sites and substantial recovery in the wetland-affected downstream sites. Omnivorous feeding behavior of macroinvertebrates was noted for the upstream sites, whereas clear trophic guilds of FFGs were suggested for the wetland-affected river zones by the stable isotope results. The results of pollution gradient analysis and feeding interactions among FFGs revealed that the urban-impacted sites showed weaker interactions when compared to upstream and wetland influenced sites. This affirms the potential importance of feeding interactions among FFGs of macroinvertebrates in water quality monitoring.  相似文献