136,564 research outputs found
Tracing technological development trajectories: A genetic knowledge persistence-based main path approach
The aim of this paper is to propose a new method to identify main paths in a
technological domain using patent citations. Previous approaches for using main
path analysis have greatly improved our understanding of actual technological
trajectories but nonetheless have some limitations. They have high potential to
miss some dominant patents from the identified main paths; nonetheless, the
high network complexity of their main paths makes qualitative tracing of
trajectories problematic. The proposed method searches backward and forward
paths from the high-persistence patents which are identified based on a
standard genetic knowledge persistence algorithm. We tested the new method by
applying it to the desalination and the solar photovoltaic domains and compared
the results to output from the same domains using a prior method. The empirical
results show that the proposed method overcomes the aforementioned drawbacks
defining main paths that are almost 10x less complex while containing more of
the relevant important knowledge than the main path networks defined by the
existing method.Comment: 20 pages, 7 figure
Separation of gas mixtures by centrifugation
Magnetohydrodynamic (MHD) centrifuge utilizing electric currents and magnetic fields produces a magnetic force which develops supersonic rotational velocities in gas mixtures. Device is superior to ordinary centrifuges because rotation of gas mixture is produced by MHD force rather than mechanical means
Wind and turbine characteristics needed for integration of wind turbine arrays into a utility system
Wind data and wind turbine generator (WTG) performance characteristics are often available in a form inconvenient for use by utility planners and engineers. The steps used by utility planners are summarized and the type of wind and WTG data needed for integration of WTG arrays suggested. These included long term yearly velocity averages for preliminary site feasibility, hourly velocities on a 'wind season' basis for more detailed economic analysis and for reliability studies, worst-case velocity profiles for gusts, and various minute-to-hourly velocity profiles for estimating the effect of longer-term wind fluctuations on utility operations. wind turbine data needed includes electrical properties of the generator, startup and shutdown characteristics, protection characteristics, pitch control response and control strategy, and electro-mechanical model for stability analysis
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Biological fieldwork provision in higher education
Fieldwork is regarded as an important component of many bioscience degree programmes. QAA benchmarks statements refer explicitly to the importance of fieldwork, although give no indication of amounts of field provision expected. Previous research has highlighted the importance of fieldwork to the learning of both subject-specific and transferable skills. However, it is unclear how the amount and type of fieldwork currently offered is being affected by the recent expansion in student numbers and current funding constraints. Here we review contemporary literature and report on the results of a questionnaire completed by bioscience tutors across 33 UK institutions. The results suggest, perhaps contrary to anecdotal evidence, that the amount of fieldwork being undertaken by students is not in decline and that on the whole, programmes contain reasonable amounts of fieldwork. The majority of programmes involved UK-based fieldwork, but a number of programmes also offered ‘exotic’ overseas fieldwork which was considered important in terms of student recruitment as well as exposing students to a diversity of field learning environments. Tutors were very clear about the benefits of fieldwork and the need to be proactive to maintain its provision
Comment on "Spectroscopic Evidence for Multiple Order Parameter Components in the Heavy Fermion Superconductor CeCoIn"
Recently, Rourke et al. reported point-contact spectroscopy results on the
heavy-fermion superconductor CeCoIn [1]. They obtained conductance spectra
on the c-axis surfaces of CeCoIn single crystals. Their major claims are
two-fold: CeCoIn has i) d-wave pairing symmetry and ii) two coexisting
order parameter components. In this Comment, we show that these claims are not
warranted by the data presented. [1] Rourke et al., Phys. Rev. Lett. 94, 107005
(2005).Comment: accepted for publication in Phys. Rev. Lett., final for
A RETAIL EVALUATION OF PROMOTIONAL TACTICS IN THE FOOD INDUSTRY
In an effort to ease communication between packaged goods manufacturers and retailers, this study investigates food retailers'Â’ preferences concerning the various promotional programs used in their stores. Through the use of a mail survey, retail executives from supermarket companies shared their perceptions of 22 specific promotional programs regarding each program'Â’s use, effectiveness, and attractiveness for future support. According to retailers, clear and consistent promotional performers include targeted direct mail, shipper displays, in-store coupons, in-ad coupons, and in-store demos and sampling. It is noted, however, that the use and perceived effectiveness of these programs may not always seem consistent. For example, retailers felt that promotions tied to local charities are relatively ineffective for increasing product movement or overall store sales, and yet this promotional tool is used by 92 percent of surveyed retailers. On the other hand, frequent shopper programs received favorable marks regarding program effectiveness, and yet they are not commonly used by retailers in this survey. Ultimately, the value that a retailer places on any given promotion is a function of that promotion'Â’s ability to meet stated retail objectives, which may extend beyond any hard sales statistics.Marketing,
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