Fred Y. Ye

h-Degree as a basic measure in weighted networks

We introduce the h-degree of a node as a basic indicator for weighted networks. The h-degree (dh) of a node is the number dh if this node has at least dh links with other nodes and the strength of each of these links is greater than or equal to dh. Based on the notion of h-degree other notions are developed such as h-centrality and h-centralization, leading to a new set of indicators characterizing nodes in a network.

Probing the h-core: an investigation of the tail–core ratio for rank distributions

The set of citations received by a set of publications consists of citations received by articles in the h-core and citations received by articles in the h-tail. Denoting the cardinalities of these fours sets as C, P, CH and CT we introduce the tail-core ratio (CT/CH) and show that in practical cases this ratio tends to increase. Introducing further the k-index, defined as k = (C/P)/(CT/CH), we show that this index decreases in most practical cases. A power law model is in accordance with these practical observations.

The Triple Helix of university-industry-government relations at the country level and its dynamic evolution under the pressures of globalization

Using data from the Web of Science (WoS), we analyze the mutual information among university, industry, and government addresses (U-I-G) at the country level for a number of countries. The dynamic evolution of the Triple Helix can thus be compared among developed and developing nations in terms of cross-sectional coauthorship relations. The results show that the Triple Helix interactions among the three subsystems U-I-G become less intensive over time, but unequally for different countries. We suggest that globalization erodes local Triple Helix relations and thus can be expected to have increased differentiation in national systems since the mid-1990s. This effect of globalization is more pronounced in developed countries than in developing ones. In the dynamic analysis, we focus on a more detailed comparison between China and the United States. Specifically, the Chinese Academy of the (Social) Sciences is changing increasingly from a public research institute to an academic one, and this has a measurable effect on Chinas position in the globalization.

The phenomenon of all-elements-sleeping-beauties in scientific literature

The phenomenon of all-elements-sleeping-beauties in science is revealed by four special cases. The ‘sleeping beauties’ prick their fingers on the ‘spindles’ so that they fall into sleep then are awakened by their ‘princes’. The authors speculate that the phenomenon could happen in scientific literatures with high quality.

The power law model and total career h-index sequences

Three variations on the power law model proposed by Egghe are fitted to four groups of h-index time series: publication-citation data for authors, journals and universities; and patent citation data for firms. It is shown that none of the power law models yields an adequate description of total career h-index sequences.

A study of the “heartbeat spectra” for “sleeping beauties”

We first introduced interesting definitions of “heartbeat” and “heartbeat spectrum” for “sleeping beauties”, based on van Raans variables. Then, we investigated 58,963 papers of Nobel laureates during 1900–2000 and found 758 sleeping beauties. By proposing and using Gs index, an adjustment of Gini coefficient, to measure the inequality of “heartbeat spectrum”, we observed that publications which possess “late heartbeats” (most citations were received in the second half of sleeping period) have higher awakening probability than those have “early heartbeats” (most citations were received in the first half of sleeping period). The awakening probability appears the highest if an articles Gs index exists in the interval [0.2, 0.6).

An investigation on mathematical models of the h-index

Based on two large data samples from ISI databases, the author evaluated the Hirsch model, the Egghe-Rousseau model, and the Glänzel-Schubert model of the h-index. The results support the Glänzel-Schubert model as a better estimation of the h-index at both journal and institution levels. If hc, hp and hpc stand for the Hirsch estimation, Egghe-Rousseau estimation, and Glänzel-Schubert estimation, respectively, then an inequality hp < h ∼ hpc < hc holds in most cases.

A quantitative relationship between per capita GDP and scientometric criteria

There exists a quantitative relationship, which can be expressed as G=kF(lgP)N, where G is per capita GDP, F gross expenditure on R&D as % of GDP, P patent applications, N Internet users per 10,000 inhabitants, and k a constant ranging from 0.4 to 1.2 in most countries. The mechanism of the relationship is explained in the paper.

Exploring the directed h-degree in directed weighted networks

Most networks in information science appear as weighted networks, while many of them (e.g. author citation networks, web link networks and knowledge flow networks) are directed networks. Based on the definition of the h-degree, the directed h-degree is introduced for measuring both weighted networks and directed networks. After analyzing the properties and derived measures of the directed h-degree an actual application of LIS journals citation network is worked out.

Power‐law link strength distribution in paper cocitation networks

A network is constructed by nodes and links, thus the node degree and the link strength appear as underlying quantities in network analysis. While the power‐law distribution of node degrees is verified as a basic feature of numerous real networks, we investigate whether the link strengths follow the power‐law distribution in weighted networks. After testing 12 different paper cocitation networks with 2 methods, fitting in double‐log scales and the Kolmogorov‐Smirnov test (K‐S test), we observe that, in most cases, the link strengths also follow the approximate power‐law distribution. The results suggest that the power‐law type distribution could emerge not only in nodes and informational entities, but also in links and informational connections.