scholarly journals Choosing the number of groups in a latent stochastic blockmodel for dynamic networks

2018 ◽  
Vol 6 (4) ◽  
pp. 469-493 ◽  
Author(s):  
RICCARDO RASTELLI ◽  
PIERRE LATOUCHE ◽  
NIAL FRIEL

AbstractLatent stochastic blockmodels are flexible statistical models that are widely used in social network analysis. In recent years, efforts have been made to extend these models to temporal dynamic networks, whereby the connections between nodes are observed at a number of different times. In this paper, we propose a new Bayesian framework to characterize the construction of connections. We rely on a Markovian property to describe the evolution of nodes' cluster memberships over time. We recast the problem of clustering the nodes of the network into a model-based context, showing that the integrated completed likelihood can be evaluated analytically for a number of likelihood models. Then, we propose a scalable greedy algorithm to maximize this quantity, thereby estimating both the optimal partition and the ideal number of groups in a single inferential framework. Finally, we propose applications of our methodology to both real and artificial datasets.

2018 ◽  
Vol 18 (01) ◽  
pp. 1850001
Author(s):  
NAOKI TAKEUCHI ◽  
SATOSHI FUJITA

Scale-free networks have several favorable properties as the topology of interconnection networks such as the short diameter and the quick message propagation. In this paper, we propose a method to construct scale-free networks in a semi-deterministic manner. The proposed algorithm extends the Bulut's algorithm for constructing scale-free networks with designated minimum degree k and maximum degree m, in such a way that: (1) it determines the ideal number of edges derived from the ideal degree distribution; and (2) after connecting each new node to k existing nodes as in the Bulut’s algorithm, it adjusts the number of edges to the ideal value by conducting add/removal of edges. We prove that such an adjustment is always possible if the number of nodes in the network exceeds [Formula: see text]. The performance of the algorithm is experimentally evaluated.


2021 ◽  
Vol 9 (3) ◽  
pp. 153
Author(s):  
Murilo Alceu de Águas ◽  
Joaquim José Frazão ◽  
Leonardo Mariano do Nascimento ◽  
João Paulo Souza Carneiro ◽  
Ariel Muncio Compagnon ◽  
...  

Lowlands represent a significant portion of agricultural areas in the world. Thus, understanding the spatial variability of the chemical and granulometric characteristics of hydromorphic soils can contribute to improving soil management and fertility. The objective of this work was to characterize spatial dependence, spatialized chemical attributes, granulometry, and the ideal number of samples in irrigated hydromorphic soil. Soil sampling was conducted in a grid of 10x10 m, in the layers of 0–0.1 and 0.1–0.2 m, totalling 432 composite samples. The evaluated attributes are as follows: pH in water, H+Al, SOM, Ca, Mg, Al, P, K, CTC, V%, Cu, Fe, Zn, Mn, clay, silt, and sand. The texture of the area was classified as loamy–sandy and free in the 0–0.1 and 0.1–0.2 m layers, respectively. The coefficient of variation of the attributes ranged from 2.71% (0–0.1m) to 149.07% (0.1–0.2m). All the attributes studied exhibited moderate to strong spatial dependence. The sample grid with a sampling interval of 20 m referring to the 0–0.1 m layer proved to be adequate. The ideal number of simple samples per composite is 19 for granulometry and macronutrients, and 28 for the micronutrients in the 0–0.1 m layer.


2018 ◽  
Author(s):  
Nicolyn Charlot ◽  
Rhonda Nicole Balzarini ◽  
Lorne Campbell

Research has shown that ideal romantic standards predict future partner characteristics and influence existing relationships, but how standards develop and change among single individuals has yet to be explored. Using the Ideal Standards Model, the present study sought to determine whether repeated experiences of romantic rejection and acceptance over time influence ideal standards, ideal flexibility, and self-perceived mate value (N = 208). Per expectations, results suggest repeated experiences of rejection result in decreases in ideal standards and self-perceived mate value and increases in ideal flexibility, though no effects emerged for acceptance. Given the predictive nature of ideal standards and the influence rejection has on such, findings from this study contribute to a greater understanding of relationship formation processes. OSF: osf.io/qy93h/


2018 ◽  
Vol 7 (4.30) ◽  
pp. 5 ◽  
Author(s):  
Zun Liang Chuan ◽  
Azlyna Senawi ◽  
Wan Nur Syahidah Wan Yusoff ◽  
Noriszura Ismail ◽  
Tan Lit Ken ◽  
...  

The grassroots of the presence of missing precipitation data are due to the malfunction of instruments, error of recording and meteorological extremes. Consequently, an effective imputation algorithm is indeed much needed to provide a high quality complete time series in assessing the risk of occurrence of extreme precipitation tragedy. In order to overcome this issue, this study desired to investigate the effectiveness of various Q-components of the Bayesian Principal Component Analysis model associates with Variational Bayes algorithm (BPCAQ-VB) in missing daily precipitation data treatment, which the ideal number of Q-components is identified by using The Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) algorithm. The effectiveness of BPCAQ-VB algorithm in missing daily precipitation data treatment is evaluated by using four distinct precipitation time series, including two monitoring stations located in inland and coastal regions of Kuantan district, respectively. The analysis results rendered the BPCA5-VB is superior in missing daily precipitation data treatment for the coastal region time series compared to the single imputation algorithms proposed in previous studies. Contrarily, the single imputation algorithm is superior in missing daily precipitation data treatment for an inland region time series rather than the BPCAQ-VB algorithm.   


2018 ◽  
Vol 7 (2.29) ◽  
pp. 967
Author(s):  
Nuraini Aisiyah ◽  
Kusmiarto .

This paper aims to describe the role of Diploma I Cadastral Surveying and Mapping Program of National Land College (DI PPK- STPN) in fulfilling the needs of Cadastral Surveyor Assistant in Indonesia. DI PPK-STPN was established in 1996 in Yogyakarta with the aim to meet the needs of Cadastral Surveyor Assistant in Adjudication Program. Previously, in Indonesia, the candidate of Cadastral Surveyor Assistant was educated through the short course program. The method is descriptive, informative, which describes ability and competence owned by alumni of Diploma I PPK-STPN. Identification of the number of alumni of Diploma I PPK-STPN can describe the number of Cadastral Surveyor Assistant of Indonesia. By looking at the number of alumni of Diploma I PPK-STPN, we can see the level of adequacy of the needs of Cadastral Surveyor Assistant in the acceleration program of land registration in Indonesia. To achieve the ideal number of Cadastral Surveyor Assistant in Indonesia, the existence of DI PPK-STPN is still needed.  


2017 ◽  
Vol 52 (8) ◽  
pp. 690-693 ◽  
Author(s):  
Victor Dias Pirovani ◽  
Dirceu Pratissoli ◽  
Marcel Oliveira Tibúrcio ◽  
José Romário de Carvalho ◽  
Alixelhe Pacheco Damascena ◽  
...  

Abstract: The objective of this work was to determine the ideal number for field release of Trichogramma galloi and T.pretiosum for controlling Duponchelia fovealis (Lepidoptera: Crambidae) in strawberry (Fragaria x ananassa). The experiment was carried out in a greenhouse, where the strawberry cultivar 'Oso Grande' was infected with 100 eggs of D.fovealis distributed on the leaf surface area of each plant. A total of 1, 2, 4, 8, 16, 32, 64, and 128 female parasitoids were released per egg of D. fovealis. The greatest level of egg parasitism, with no differences for the species of Trichogramma, was observed at the densities of four and eight parasitoids per egg of D.fovealis, considered ideal for field release.


2019 ◽  
Vol 112 (3) ◽  
pp. e96-e97
Author(s):  
Sydney Chang ◽  
Dmitry Gounko ◽  
Joseph A. Lee ◽  
Melissa Bell ◽  
Margaret Daneyko ◽  
...  

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