36,992 research outputs found
Household technology acceptance heterogeneity in computer adoption
Technology policy analysis and implementation relies on knowledge and understanding of the "adoption gap" in information technologies among different groups of consumers. Factors that explain the residential "digital divide" also need to be identified and quantified. Through the application of survey data we provide an enhanced understanding of the key factors involved in the choice of residential computer adoption. These choices are analysed using a discrete choice model that reveals that sociodemographic factors strongly influence the adoption of the residential computer. Moreover, we apply the basic findings of the Technology Adoption Model (TAM) into the discrete choice framework heteroscedastically to deepen our understanding of why some households choose not to have computers; above and beyond what may be explained by socio-demography alone. Generally, we find that computer adoption is sensitive to household digital division measures and that the model fit improves with the heteroscedastic addition of the TAM factors. These findings are important for market planners and policymakers who wish to understand and quantify the impact of these factors on the digital divide across different household types, as defined by the TAM model
Alternative Adaptive Filter Structures for Improved Radio Frequency Interference Cancellation in Radio Astronomy
In radio astronomy, reference signals from auxiliary antennas that receive
only the radio frequency interference (RFI) can be modified to model the RFI
environment at the astronomy receivers. The RFI can then be canceled from the
astronomy signal paths. However, astronomers typically only require signal
statistics. If the RFI statistics are changing slowly, the cancellation can be
applied to the signal correlations at a much lower rate than is required for
standard adaptive filters. In this paper we describe five canceler setups;
precorrelation and postcorrelation cancelers that use one or two reference
signals in different ways. The theoretical residual RFI and added noise levels
are examined and are demonstrated using microwave television RFI at the
Australia Telescope Compact Array. The RFI is attenuated to below the system
noise, a reduction of at least 20 dB. While dual-reference cancelers add more
reference noise than single-reference cancelers, this noise is zero-mean and
only adds to the system noise, decreasing the sensitivity. The residual RFI
that remains in the output of single-reference cancelers (but not
dual-reference cancelers) sets a nonzero noise floor that does not act like
random system noise and may limit the achievable sensitivity. Thus,
dual-reference cancelers often result in superior cancellation. Dual-reference
precorrelation cancelers require a double-canceler setup to be useful and to
give equivalent results to dual-reference postcorrelation cancelers.Comment: 11 pages created using emulateap
Entrepreneurs'' attitude towards the computer and its effect on e-business adoption
This paper presents research exploring further the concept that many SMEs do not adopt computer based technologies due to decision maker's negative attitudes towards computers generally. Importantly, by assessing the entrepreneur's belief structure, we provide quantitative evidence how SMEs, particularly micros, are affected. Earlier research that addresses technology acceptance model (TAM) suggests that TAM parameters are particularly influential factors of e-commerce adoption, as perceived by top managers of SMEs. The model we develop is tested using a sample of 655 enterprises. The information was gathered, via a telephone survey of UK SMEs, from decisions makers in the enterprise. Technically, the paper uses k-means cluster analysis to segment respondents using the TAM perceptions, ease of use, usefulness and enjoyment. Based on two determined segments we look at the differential rate of adoption of internet, and the potential adoption of new e-collaborative technologies like video conferencing and electronic whiteboards. The diffusion of internet for low IT utility (LIT) segments was considerably slower than in the high utility segment (HIT). Similarly, the anticipated adoption of e-collaboration technologies was much lower for LIT than HIT. Interestingly, we find that LIT is populated by more micro SMEs than HIT. The results we present are limited however as our sample is considerably underweight in micro SMEs, suggesting that the problem may be much larger in the economy than our model predicts. For policy makers, this research confirms the value of knowledge transfer programs to SMEs in the form of technology support. Our research shows that organisations which have dedicated IT support will tend to be more advanced technologically than those that do not. The implication for entrepreneurs is if they can be persuaded that a technological route is beneficial to them, and that suitable support can be provided via KT, then operational efficiency gains could be made. This paper contributes to knowle
The search for innovators and early adopters of e-collaborative technologies within small and medium sized enterprises in the UK
New product diffusion theory predicts that innovators and early adopters are critical to the success of new innovations. The rate at which enterprises adopt e-Science technologies must therefore rely upon reliable market intelligence so that the critical early stages of adoption are successfully navigated by developers and planners. Failure to understand attitudes towards new technologies can lead to even useful technologies being under-adopted. This paper applies a survey based methodology to develop estimates of demand for web based virtual Collaborative technologies. We show that approximately 76% of the 1029 firms that we interviewed are technologically ready to deploy these technologies. We also show that 10% of all firms are ready look at these technologies as solutions to collaborative problem solving
Search for the second forbidden beta decay of 8B to the ground state of 8Be
A significant decay branch of 8B to the ground state of 8Be would extend the
solar neutrino spectrum to higher energies than anticipated in the standard
solar models. These high-energy neutrinos would affect current neutrino
oscillation results and also would be a background to measurements of the hep
process. We have measured the delayed alpha particles from the decay of 8B,
with the goal of observing the two 46-keV alpha particles arising from the
ground-state decay. The 8B was produced using an in-flight radioactive beam
technique. It was implanted in a silicon PIN-diode detector that was capable of
identifying the alpha-particles from the 8Be ground state. From this
measurement we find an upper limit (at 90% confidence level) of 7.3 x 10^{-5}
for the branching ratio to the ground state. In addition to describing this
measurement, we present a theoretical calculation for this branching ratio.Comment: One reference corrected. Minor edits in tex
Synchronizing Sequencing Software to a Live Drummer
Copyright 2013 Massachusetts Institute of Technology. MIT allows authors to archive published versions of their articles after an embargo period. The article is available at
Multistep self-assembly of heteroleptic magnesium and sodium-magnesium benzamidinate complexes
Reaction of the magnesium bis-alkyl Mg(CH2SiMe3)(2) and the sodium amide NaHMDS (where HMDS = N(SiMe3)(2)) with benzonitrile yields the homometallic heteroleptic complex [PhC(NSiMe3)(2)Mg{mu-NC(CH2SiMe3)Ph}](2) (1). It appears that at least six independent reactions must have occurred in this one-pot reaction to arrive at this mixed benzamidinate ketimido product. Two benzonitrile solvated derivatives of Mg(CH2SiMe3)(2) (5a and 5b) have been synthesized, with 5a crystallographically characterized as a centrosymmetric (MgC)(2) cyclodimer. When, the components of 5a are allowed to react for longer, partial addition of the Mg-alkyl unit across the C N triple bond occurs to yield the trimeric species (Me3SiCH2)(2)Mg-3[mu-N=C(CH2SiMe3)Ph](4)center dot 2N CPh (6), with bridging ketimido groups and terminal alkyl groups. Finally, using the same starting materials as that which produced 1, but altering their order of addition, a magnesium bis-alkyl unit is inserted into the Na-N bonds of a benzamidinate species to yield a new sodium magnesiate complex, PhC(NSiMe3)(2)Mg(mu-CH2SiMe3)(2)Na center dot 2TMEDA (7). The formation of 7 represents a novel (insertion) route to mixed-metal species of this kind and is the first Such example to contain a bidentate terminal anion attached to the divalent metal center. All new species are characterized by H-1 and C-13 NMR spectroscopy and where appropriate by IR spectroscopy. The solid-state structures of complexes 1, 5a, and 7 have also been determined and are disclosed within
Middle managers in secondary schools: rhetoric and reality.
This thesis is concerned with contrasting the rhetoric and the reality experienced by
teacher middle managers. A significant number of teachers interviewed in the study see this
rhetoric as being generated at and promulgated from the 'centre. The thesis considers how this
centrally devised rhetoric influences teacher middle managers in secondary schools. The thesis
utilized a 'grounded theoryapproach. Class teachers, teacher middle managers and senior
managers in two secondary schools were interviewed using semi-structured interviews. These teachers were also observed as they interacted with colleagues in both formal and informal situations. Those teacher middle managers interviewed and observed were concerned about the need to give considerable amounts of time in order to carry out the many tasks they were expected to
undertake. The findings suggest that teacher middle managers perceive the public nature of teaching and consequently value the cknowledgement and approval of colleagues and pupils. The findings also suggest that teacher middle managers were keen to develop a balance between the demands made of them at home and school. Interview responses also suggest that class teachers and teacher middle managers seek certainty and control in their working lives but understand the need to compromise and develop coping strategies. Most significantly the findings suggest that teachers were seeking to hide (by using 'camouflage') from their senior managers and class teacher colleagues, the reality of their day-to-day teaching experiences. There is also some evidence that teacher middle managers are engaging in 'collusion' with class teacher colleagues and senior managers to expedite the meeting of bureaucratic 'targets' and rhetorical 'standards'
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