Experience versus Talent Shapes the Structure of the Web

We use sequential large-scale crawl data to empirically investigate and validate the dynamics that underlie the evolution of the structure of the web. We find that the overall structure of the web is defined by an intricate interplay between experience or entitlement of the pages (as measured by the number of inbound hyperlinks a page already has), inherent talent or fitness of the pages (as measured by the likelihood that someone visiting the page would give a hyperlink to it), and the continual high rates of birth and death of pages on the web. We find that the web is conservative in judging talent and the overall fitness distribution is exponential, showing low variability. The small variance in talent, however, is enough to lead to experience distributions with high variance: The preferential attachment mechanism amplifies these small biases and leads to heavy-tailed power-law (PL) inbound degree distributions over all pages, as well as over pages that are of the same age. The balancing act between experience and talent on the web allows newly introduced pages with novel and interesting content to grow quickly and surpass older pages. In this regard, it is much like what we observe in high-mobility and meritocratic societies: People with entitlement continue to have access to the best resources, but there is just enough screening for fitness that allows for talented winners to emerge and join the ranks of the leaders. Finally, we show that the fitness estimates have potential practical applications in ranking query results

Noise characteristics of upper surface blown configurations: Analytical Studies

Noise and flow results of upper surface blown configurations were analyzed. The dominant noise source mechanisms were identified from experimental data. From far-field noise data for various geometric and operational parameters, an empirical noise prediction program was developed and evaluated by comparing predicted results with experimental data from other tests. USB aircraft compatibility studies were conducted using the described noise prediction and a cruise performance data base. A final design aircraft was selected and theory was developed for the noise from the trailing edge wake assuming it as a highly sheared layer

A risk-adjusted performance history of public and private market real estate investment, 1978-1997

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Urban Studies and Planning, 1999.Includes bibliographical references (leaves 51-54).Since the inception of the Real Estate Investment Trust ("REIT"), the relative efficiency of the public and private real estate markets has been the subject of debate. Consequently, a determination of the more efficient real estate investment vehicle will probably have a significant effect on the future flow of capital into all real estate assets. This thesis proposes to identify which real estate investment medium, public or private, has provided greater efficiency to its investors as measured by risk adjusted total return over the 20 year period from 1978-1997. The initial objective of this thesis was to create a publicly traded real estate equity index(the "Thesis index") for comparison to the existing National Association of Real Estate Investment Trusts ("NAREIT") equity index in an effort to replicate the returns of the latter. This equity Thesis index is an annual weighted compilation of the total returns of each existing equity REIT, as identified by a query of the Compustat database, for each given year from 1978 through 1997. Returns were calculated as of the calendar year end commencing in 1978 and continuing through calendar year end 1997. The core objective of this thesis was to ultimately compare the de-levered Thesis index to the existing National Council of Real Estate Investment Fiduciaries ("NCREIF") index in order to determine which index has provided a greater risk adjusted return over the time series in question. Given the disparities in the risk profiles of the underlying indices and the need to ensure a homogeneous comparison, adjustments to the Thesis index have been made in order to compensate for leverage in the REIT capital structure, for the presence of development risk in the current REIT asset base, and for the respective weight of each real estate asset class within the NCREIF index.by Mark P. Moriarty and Pennock J. Yeatman, IV.S.M

Frictional behaviour of simulated muscovite fault gouge at shear strains up to 120 and temperatures of 20-600 ºC

see Abstract Volum