Spatiotemporal Co-occurrence Pattern (STCOP) Mining

2018 ◽  
pp. 55-69
Author(s):  
Berkay Aydin ◽  
Rafal A. Angryk
Keyword(s):  
Occurrence Pattern

scholarly journals A Social Recommendation Based on Metric Learning and Users’ Co-Occurrence Pattern

Symmetry ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 2158
Author(s):  
Xin Zhang ◽  
Jiwei Qin ◽  
Jiong Zheng
Keyword(s):  
Matrix Factorization ◽  
Triangle Inequality ◽  
Metric Learning ◽  
Social Recommendation ◽  
Rating Data ◽  
Fine Grained ◽  
Information Metric ◽  
Occurrence Pattern ◽  
Public Datasets ◽  
Occurrence Patterns

For personalized recommender systems, matrix factorization and its variants have become mainstream in collaborative filtering. However, the dot product in matrix factorization does not satisfy the triangle inequality and therefore fails to capture fine-grained information. Metric learning-based models have been shown to be better at capturing fine-grained information than matrix factorization. Nevertheless, most of these models only focus on rating data and social information, which are not sufficient for dealing with the challenges of data sparsity. In this paper, we propose a metric learning-based social recommendation model called SRMC. SRMC exploits users’ co-occurrence patterns to discover their potentially similar or dissimilar users with symmetric relationships and change their relative positions to achieve better recommendations. Experiments on three public datasets show that our model is more effective than the compared models.

Variation of cyanobacteria occurrence pattern and environmental factors in Lake Juam

2019 ◽  
Vol 37 (4) ◽  
pp. 640-651
Author(s):  
Hyeonsu Chung ◽  
Misun Son ◽  
Hui-Seong Ryu ◽  
Chang Hee Park ◽  
Rury Lee ◽  
...  
Keyword(s):  
Environmental Factors ◽  
Occurrence Pattern

scholarly journals OrthoVenn2: a web server for whole-genome comparison and annotation of orthologous clusters across multiple species

2019 ◽  
Vol 47 (W1) ◽  
pp. W52-W58 ◽  
Author(s):  
Ling Xu ◽  
Zhaobin Dong ◽  
Lu Fang ◽  
Yongjiang Luo ◽  
Zhaoyuan Wei ◽  
...  
Keyword(s):  
Web Server ◽  
Venn Diagram ◽  
Orthologous Group ◽  
Genome Comparison ◽  
Species Number ◽  
Whole Genome ◽  
Functional Annotations ◽  
Occurrence Pattern ◽  
Multiple Species ◽  
User Friendly

Abstract OrthoVenn is a powerful web platform for the comparison and analysis of whole-genome orthologous clusters. Here we present an updated version, OrthoVenn2, which provides new features that facilitate the comparative analysis of orthologous clusters among up to 12 species. Additionally, this update offers improvements to data visualization and interpretation, including an occurrence pattern table for interrogating the overlap of each orthologous group for the queried species. Within the occurrence table, the functional annotations and summaries of the disjunctions and intersections of clusters between the chosen species can be displayed through an interactive Venn diagram. To facilitate a broader range of comparisons, a larger number of species, including vertebrates, metazoa, protists, fungi, plants and bacteria, have been added in OrthoVenn2. Finally, a stand-alone version is available to perform large dataset comparisons and to visualize results locally without limitation of species number. In summary, OrthoVenn2 is an efficient and user-friendly web server freely accessible at https://orthovenn2.bioinfotoolkits.net.

Habitat filtering of six coexisting Heliconia species in a lowland tropical rain forest in Amazonian Ecuador

2019 ◽  
Vol 35 (2) ◽  
pp. 91-94 ◽  
Author(s):  
Elizabeth L. Tokarz ◽  
Pablo Álvia ◽  
Renato Valencia ◽  
Simon A. Queenborough
Keyword(s):  
Rain Forest ◽  
National Park ◽  
Distribution Patterns ◽  
Common Species ◽  
Habitat Filtering ◽  
Yasuni National Park ◽  
Amazonian Ecuador ◽  
Amazonian Rain Forest ◽  
Random Manner ◽  
Occurrence Pattern

AbstractHerbaceous plants are often under-studied in tropical forests, despite their high density and diversity, and little is known about the factors that influence their distribution at microscales. In a 25-ha plot in lowland Amazonian rain forest in Yasuní National Park, Ecuador, we censused six species of Heliconia (Heliconiaceae) in a stratified random manner across three topographic habitat types. We observed distribution patterns consistent with habitat filtering. Overall, more individuals occurred in the valley (N = 979) and slope (N = 847) compared with the ridge (N = 571) habitat. At the species level, Heliconia stricta (N = 1135), H. spathocircinata (N = 309) and H. ortotricha (N = 36) all had higher abundance in the valley and slope than ridge. Further, H. vellerigera (N = 20) was completely absent from the ridge. Conversely, H. velutina (N = 903) was most common in the drier ridge habitat. The two most common species (H. stricta and H. velutina) had a reciprocal or negative co-occurrence pattern and occurred preferentially in valley versus ridge habitats. These results suggest that taxa within this family have different adaptations to the wetter valley versus the drier ridge and that habitat partitioning contributes to coexistence.

A Cyclotron Theory for the Beaming Pattern of Jupiter’s Decametric Radio Emission

1981 ◽  
Vol 4 (2) ◽  
pp. 221-226 ◽  
Author(s):  
R. G. Hewitt ◽  
D. B. Melrose ◽  
K. G. Rönnmark
Keyword(s):  
Magnetic Field ◽  
Radio Emission ◽  
Observational Data ◽  
Theoretical Interpretation ◽  
Theoretical Interest ◽  
Hollow Cone ◽  
The Past ◽  
Jovian Magnetosphere ◽  
Half Angle ◽  
Occurrence Pattern

Ground-based observations of Jupiter’s decametric radio emission (DAM) have been reviewed by Ellis (1965), Warwick (1967, 1970) and Carr and Gulkis (1969). A startling feature of DAM is the modulating effect of Io, and interpretation of the Io effect has dominated theoretical discussions of DAM until quite recently, specifically until the fly-by s of Voyagers 1 and 2. The Voyager data showed that the DAM appears as nested arcs in the frequency-Jovian longitude plane (Warwick et al. 1979, Boischot et al. 1981). The interpretation of this arc structure has been of primary theoretical interest over the past two years. The most widely adopted explanation is that the emission from each point is confined to the surface of a hollow cone (Goldstein and Thieman 1981). This idea is not new: emission on the surface of a cone was discussed by Ellis and McCulloch (1963); Dulk (1967) derived detailed parameters for the cone (half angle 79° width 1°) from the occurrence pattern of DAM; and Goldreich and Lynden-Bell (1969) presented a theoretical interpretation of it. More recently Goldstein et al. (1979) used observational data on the Jovian magnetic field in deriving properties of the required emission cone. It seems that one requires the properties of the emission cone to vary with position in the Jovian magnetosphere to account for the nested arc pattern (Goldstein and Thieman 1981; Gurnett and Goertz 1981).

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