Social Network Analysis

https://www.linkgroup.hu/docs/13PharmTher.pdf

Structure and dynamics of molecular networks: A novel paradigm of drug discovery: A comprehensive review

What manner of organization is the National Bureau of Economic Research? How does it select research topics? Who does the work and what kind of tasks do they perform? Where do the funds come from? How does the National Bureau safeguard the scientific quality of its findings? How are the results disseminated? Visitors to the National Bureau often ask these and similar questions; perhaps the answers will be of interest to readers of the American Statistician. The National Bureau of Economic Research is a private non-profit corporation, formed, according to its charter, "to conduct, or assist in the making of exact and impartial investigations in the field of economic, social and industrial science, and to this end to cooperate with governments, universities, learned societies, and individuals." Hence it is not a government agency, nor an adjunct of a university, nor does it sell research services. The revenue from the only products it does sell, publications, barely covers the printing costs. Its funds are contributed by philanthropic foundations, by trade and professional organizations, by business concerns, trade unions, and individuals. Contributions are usually on a yearly basis, but some grants cover several years. Some of the funds are earmarked for specific studies; the balance goes to support a general program of research. The National Bureau is governed by a Board of Directors numbering about thirty, selected to represent various institutions and diverse points of view on economic problems. Over the years since the Bureau was founded in 1920 this body of men has made a significant contribution to the development of scientific inquiry in economics, both within the National Bureau and outside. Such outstanding economists as Wesley C. Mitchell, George E. Roberts, Allyn A. Young, Edwin F. Gay, Thomas S. Adams, and John R. Commons have been among its members. At the present time professors from a dozen universities are on the Board. Also, Directors from each of the following organizations are elected: American Statistical Association, American Economic Association, American Farm Economic Association, Economic History Association, American Institute of Accountants, American Management Association, Congress of Industrial Organizations, and American Federation of Labor. Finally, there is a group of Directors at Large, men from varied walks of life with an abiding interest in economic research. The Board serves an important function not only in shaping the broad lines of the research program but also in safeguarding the quality of the results. Matters of policy requiring prompt action are handled by an Executive Committee of eleven, elected by the Board from its membership. Arthur F. Burns, the Director of Research, is the member of the Committee who is directly responsible for the research program. The members of the research staff, numbering about twenty-five, direct the individual studies, and are aided in their work by upwards of forty-five research assistants. A staff of typists, bookkeepers, mimeograph operators, etc., brings the total payroll of the National Bureau to roughly a hundred persons. William J. Carson, the Executive Director, handles the Bureau's finances, accounts, and other administrative matters. Not all the employees of the National Bureau work at the main office at 1819 Broadway, New York City. DuLr Financial Research Program is housed at "Hillside," an estate about 10 miles north of Manhattan overlooking the HuLdson River. Other National BureauL investigators are to be fotund at various universities throughout the United States, since cooperative arrangements are maintained with a number of universities that permit their facultv members to engage in National Butreau studies. Government agencies, too, cooperate in similar ways. Such cooperative relationships are a vital feature of our work, and we try to foster them in many ways. The growing acceptance on the part of universities of the view that research is part of the job of a faculty member has helped to make these efforts productive. For example, for a number of years we have appointed promising young men or women holding university positions as Research Associates for one year. The objective is to enable scholars to pursue their research interests in fields in which the National Bureau also has an interest. Since 1930 twenty-six Research Associates, coming from eighteen American colleges or universities and two foreign universities, have been appointed under the plan. The work of several committees is another example of cooperation for the purpose of advancing research. Two committees, one on financial and the other on fiscal research, help to guide our studies in these areas. They are composed of experts from universities, government agencies, and private business. In 1935 the Universities-National Bureau Committee was established for the express purpose of promoting contact

The National Bureau of Economic Research

Purpose - The aim of this paper is to present a sampling method using virtual networks to study "hard-to-reach" populations. In the ambit of social research, the use of new technologies is still questioned because the selection bias is an obstacle to carry on scientific research on the Internet. In this regard, the authors' hypothesis is that the use of social networking sites (Web 2.0) can be effective for the study of "hard-to-reach" populations. The main advantages of this technique are that it can expand the geographical scope and facilitates the identification of individuals with barriers to access. Therefore, the use of virtual networks in non-probabilistic samples can increase the sample size and its representativeness. Design/methodology/approach - To test this hypothesis, a virtual method was designed using Facebook to identify Argentinean immigrant entrepreneurs in Spain (214 cases). A characteristic of this population is that some individuals are administratively invisible in national statistics because they have double nationality (non-EU and EU). The use of virtual sampling was combined with an online questionnaire as a complementary tool for Web 2.0 research in behavioural sciences. Findings - The number of cases detected by Facebook and the virtual response rate is higher than traditional snowball technique. The explanation is that people increase their level of confidence because the researcher shows his personal information (Facebook's profile) and also participates in their groups of interest (Facebook's groups). Moreover, the online questionnaires administration allows the quality of the information to be controlled and avoids duplication of cases. Originality/value - The present article is the first that uses Facebook as an instrument to study immigrants. Therefore its adoption represents a great challenge in the social research field because there are many barriers of access and search. It also proposes a novel mix of traditional methodologies updated with the use of new virtual possibilities of studying hard to reach populations, especially in areas of social research where the contributions of these methods are less developed.

Social research 2.0: virtual snowball sampling method using Facebook

Journal Of The American Statistical Association V-27

In directed networks, reciprocal links have dramatic effects on dynamical processes, network growth, and higher-order structures such as motifs and communities. While the reciprocity of binary networks has been extensively studied, that of weighted networks is still poorly understood, implying an ever-increasing gap between the availability of weighted network data and our understanding of their dyadic properties. Here we introduce a general approach to the reciprocity of weighted networks, and define quantities and null models that consistently capture empirical reciprocity patterns at different structural levels. We show that, counter-intuitively, previous reciprocity measures based on the similarity of mutual weights are uninformative. By contrast, our measures allow to consistently classify different weighted networks according to their reciprocity, track the evolution of a network's reciprocity over time, identify patterns at the level of dyads and vertices, and distinguish the effects of flux (im)balances or other (a)symmetries from a true tendency towards (anti-)reciprocation.

/pdf/reciprocity-of-weighted-networks-2q6tgvbwzg.pdf

Reciprocity of weighted networks

The rebound effect: An evolutionary perspective

Evaluation of the energy efficiency evolution in the European road freight transport sector

Evaluation of the environmental sustainability of a micro CHP system fueled by low-temperature geothermal and solar energy

In this review we establish various connections between complex networks and symmetry. While special types of symmetries (e.g., automorphisms) are studied in detail within discrete mathematics for particular classes of deterministic graphs, the analysis of more general symmetries in real complex networks is far less developed. We argue that real networks, as any entity characterized by imperfections or errors, necessarily require a stochastic notion of invariance. We therefore propose a definition of stochastic symmetry based on graph ensembles and use it to review the main results of network theory from an unusual perspective. The results discussed here and in a companion paper show that stochastic symmetry highlights the most informative topological properties of real networks, even in noisy situations unaccessible to exact techniques.

Franco Ruzzenenti

Papers

Reciprocity of weighted networks

The rebound effect: An evolutionary perspective

Evaluation of the energy efficiency evolution in the European road freight transport sector

Evaluation of the environmental sustainability of a micro CHP system fueled by low-temperature geothermal and solar energy

Complex Networks and Symmetry I: A Review