Index Space Research Articles

Efficient structural graph clustering

Graph clustering is a fundamental problem widely experienced across many industries. The structural graph clustering (SCAN) method obtains not only clusters but also hubs and outliers. However, the clustering results closely depend on two sensitive parameters, ϵ and μ, while the optimal parameter setting depends on different graph properties and various user requirements. Moreover, all existing SCAN solutions need to scan at least the whole graph, even if only a small number of vertices belong to clusters. In this paper we propose an index-based method for SCAN. Based on our index, we cluster the graph for any ϵ and μ in O (Σ c ϵℂ | E C |) time, where ℂ is the result set of all clusters and | E C | is the number of edges in a specific cluster C. In other words, the time expended to compute structural clustering depends only on the result size, not on the size of the original graph. Our index's space complexity is bounded by O ( m ), where m is the number of edges in the graph. To handle dynamic graph updates, we propose algorithms and several optimization techniques for maintaining our index. We conduct extensive experiments to practically evaluate the performance of all our proposed algorithms on 10 real-world networks, one of which contains more than 1 billion edges. The experimental results demonstrate that our approaches significantly outperform existing solutions.

Velocidade periférica do disco em mecanismos dosadores de sementes de milho e soja

O objetivo deste trabalho foi avaliar o efeito da velocidade periférica do disco dosador de sementes em mecanismos dosadores pneumáticos e de disco alveolado horizontal, com as culturas do milho e soja, em ensaio de laboratório. Os tratamentos foram compostos por quatro velocidades periféricas (0,09, 0,18, 0,28 e 0,38m s-1) em combinação com quatro mecanismos dosadores (dois pneumáticos de pressão negativa e dois de disco alveolado horizontal) em delineamento blocos ao acaso com três repetições. Os mecanismos foram comparados por teste de médias e, para as velocidades periféricas, traçaram-se equações de regressão. Foram avaliados os percentuais de espaçamentos aceitáveis, múltiplos e falhos entre sementes por meio do espaçamento teórico nominal resultante de cada tratamento. O percentual de espaçamentos aceitáveis reduziu de maneira linear com o aumento da velocidade periférica do disco para ambas as culturas. Para a cultura do milho, os mecanismos dosadores pneumáticos apresentaram resultados superiores aos de disco alveolado nas velocidades periféricas mais elevadas. Para a cultura da soja, os dosadores pneumáticos apresentaram melhor desempenho na média dos tratamentos. De maneira geral, quanto menor a velocidade periférica do disco, melhor a regularidade de distribuição de sementes de milho e soja.

Relationship between alignment conditions of teeth in anterior segments and dental health.

The purpose of the study was to examine the association between alignment conditions of anterior teeth and dental health in 15-year-old adolescents. The study group consisted of 74 females and 70 males with 6 anterior teeth in both jaws. The following parameters were assessed: plaque index (P1I), gingival index (GI), probing depth (PD), space index (SpI), filled surfaces (FS), and the NONAS-i.e., the number of non-aligned proximal tooth surfaces in each jaw counted on model casts. Statistical examination of the data was performed using chi 2 tests of association and homogeneity and correlation coefficient analyses. In both sexes and both jaws, anterior tooth segments with none or few non-aligned teeth had a more favourable periodontal state than segments with an increased number of non-aligned teeth. Likewise, tooth segments with none or few non-aligned teeth had a reduced frequency of proximal fillings compared to segments with an increased number of non-aligned teeth. In males, the distribution of restorations in the anterior segment of the lower jaw was relatively homogeneous in the 3 groups.

Effects on dental health of spacing of teeth in anterior segments.

The purpose of the study was to examine the relationship between spacing and dental health in 15-year-old adolescents. The whole sample consisted of 156 subjects. Out of them, 74 females and 73 males with 6 anterior teeth made up the study group for examination of the upper jaw. 75 females and 75 males had 6 anterior teeth in the lower jaw and made up the study group for examination of the lower jaw. The Plaque Index (PlI) and the Gingival Index (GI) were recorded. Probing depths (PD) were measured as explained by Glavind & Løe. Filled surfaces (FS) were taken from the individual case sheets and controlled clinically. The spacing of the individuals was assessed by counting the number of proximal surfaces without visible contact with the adjacent proximal surfaces, on model casts. The sum of proximal surfaces without contact made up the Space Index (SpI) of the individual jaw. Parametric and non-parametric statistical methods were used to analyze the data. In both sexes and both jaws proximal surfaces without interdental contact had a more favourable periodontal condition than surfaces with contact. In the upper jaw of both sexes, proximal surfaces without interdental contact had a reduced number of filled surfaces compared to surfaces with contact. The linear relationship between SpI and FS was significant, i.e., an increased number of surfaces without contact was accompanied by a reduced number of filled surfaces. In the lower jaw, the differences between the SpI groups and the linear relationship between SpI and FS did not reach significance. In both sexes and both jaws, proximal surfaces without fillings had a more favourable periodontal state compared to surfaces with fillings. Indications are that the summation effect of the presence of interdental contact and the presence of fillings contributed to the differences in periodontal condition between surfaces with and without interdental contact.