927 resultados para Difference frequency generation (DFG)


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I am suspicious of tools without a purpose - tools that are not developed in response to a clearly defined problem. Of course tools without a purpose can still be useful. However the development of first generation CAD was seriously impeded because the solution came before the problem. We are in danger of repeating this mistake if we do not clarify the nature of the problem that we are trying to solve with the next generation of tools. Back in the 1980s I used to add a postscript slide at the end of CAD conference presentations and the applause would invariably turn to concern. The slide simple asked: can anyone remember what it was about design that needed aiding before we had computer aided design?

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The aim of this study was to characterise and quantify the fungal fragment propagules derived and released from several fungal species (Penicillium, Aspergillus niger and Cladosporium cladosporioides) using different generation methods and different air velocities over the colonies. Real time fungal spore fragmentation was investigated using an Ultraviolet Aerodynamic Particle Sizer (UVASP) and a Scanning Mobility Particle Sizer (SMPS). The study showed that there were significant differences (p < 0.01) in the fragmentation percentage between different air velocities for the three generation methods, namely the direct, the fan and the fungal spore source strength tester (FSSST) methods. The percentage of fragmentation also proved to be dependant on fungal species. The study found that there was no fragmentation for any of the fungal species at an air velocity ≤ 0.4 m/s for any method of generation. Fluorescent signals, as well as mathematical determination also showed that the fungal fragments were derived from spores. Correlation analysis showed that the number of released fragments measured by the UVAPS under controlled conditions can be predicted on the basis of the number of spores, for Penicillium and Aspergillus niger, but not for Cladosporium cladosporioides. The fluorescence percentage of fragment samples was found to be significantly different to that of non-fragment samples (p < 0.0001) and the fragment sample fluorescence was always less than that of the non-fragment samples. Size distribution and concentration of fungal fragment particles were investigated qualitatively and quantitatively, by both UVAPS and SMPS, and it was found that the UVAPS was more sensitive than the SMPS for measuring small sample concentrations, and the results obtained from the UVAPS and SMAS were not identical for the same samples.

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Online technological advances are pioneering the wider distribution of geospatial information for general mapping purposes. The use of popular web-based applications, such as Google Maps, is ensuring that mapping based applications are becoming commonplace amongst Internet users which has facilitated the rapid growth of geo-mashups. These user generated creations enable Internet users to aggregate and publish information over specific geographical points. This article identifies privacy invasive geo-mashups that involve the unauthorized use of personal information, the inadvertent disclosure of personal information and invasion of privacy issues. Building on Zittrain’s Privacy 2.0, the author contends that first generation information privacy laws, founded on the notions of fair information practices or information privacy principles, may have a limited impact regarding the resolution of privacy problems arising from privacy invasive geo-mashups. Principally because geo-mashups have different patterns of personal information provision, collection, storage and use that reflect fundamental changes in the Web 2.0 environment. The author concludes by recommending embedded technical and social solutions to minimize the risks arising from privacy invasive geo-mashups that could lead to the establishment of guidelines for the general protection of privacy in geo-mashups.

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What began as the “account manager’s conscience” has grown to be top-of-mind in Australian advertising today. Account planning is a hybrid discipline which uses research to bring the consumer voice to the campaign process during strategy generation, creative development and evaluation. In Australia, account planning is subjected to the “Vegemite Factor” where planners are spread too thinly across accounts and much of the market is dominated by freelance researchers and planners. This unique environment has shaped many different perceptions of account planning in Australia. These are compared with an international definition of account planning and the current research. While many basic tenants of the definition are shared by Australian advertising professionals, the difference appears to be in the ongoing nature, team approach and level of commitment. In Australia, account planners seem to be more facilitators of the strategic direction, than directors of it. Instead of exerting a sustained influence across the campaign, most energy appears to be expended at the start of campaign development, rather than extending through to its evaluation.

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PURPOSE: To explore the effects of glaucoma and aging on low-spatial-frequency contrast sensitivity by using tests designed to assess performance of either the magnocellular (M) or parvocellular (P) visual pathways. METHODS: Contrast sensitivity was measured for spatial frequencies of 0.25 to 2 cyc/deg by using a published steady- and pulsed-pedestal approach. Sixteen patients with glaucoma and 16 approximately age-matched control subjects participated. Patients with glaucoma were tested foveally and at two midperipheral locations: (1) an area of early visual field loss, and (2) an area of normal visual field. Control subjects were assessed in matched locations. An additional group of 12 younger control subjects (aged 20-35 years) were also tested. RESULTS: Older control subjects demonstrated reduced sensitivity relative to the younger group for the steady (presumed M)- and pulsed (presumed P)-pedestal conditions. Sensitivity was reduced foveally and in the midperiphery across the spatial frequency range. In the area of early visual field loss, the glaucoma group demonstrated further sensitivity reduction relative to older control subjects across the spatial frequency range for both the steady- and pulsed-pedestal tasks. Sensitivity was also reduced in the midperipheral location of "normal" visual field for the pulsed condition. CONCLUSIONS: Normal aging results in a reduction of contrast sensitivity for the low-spatial-frequency-sensitive components of both the M and P pathways. Glaucoma results in a further reduction of sensitivity that is not selective for M or P function. The low-spatial-frequency-sensitive channels of both pathways, which are presumably mediated by cells with larger receptive fields, are approximately equivalently impaired in early glaucoma.

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CFO and I/Q mismatch could cause significant performance degradation to OFDM systems. Their estimation and compensation are generally difficult as they are entangled in the received signal. In this paper, we propose some low-complexity estimation and compensation schemes in the receiver, which are robust to various CFO and I/Q mismatch values although the performance is slightly degraded for very small CFO. These schemes consist of three steps: forming a cosine estimator free of I/Q mismatch interference, estimating I/Q mismatch using the estimated cosine value, and forming a sine estimator using samples after I/Q mismatch compensation. These estimators are based on the perception that an estimate of cosine serves much better as the basis for I/Q mismatch estimation than the estimate of CFO derived from the cosine function. Simulation results show that the proposed schemes can improve system performance significantly, and they are robust to CFO and I/Q mismatch.

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Much of the literature on clusters has focused on the economic advantages of clusters and how these can be achieved in terms of competition, regional development and local spillovers. Some studies have focused at the level of the individual firm however human resource management (HRM) in individual clustered firms has received scant attention. This paper innovatively utilises the extended Resource Based View (RBV) of the firm as a framework to conceptualise the human resource processes of individual firms within a cluster. RBV is argued as a useful tool as it explains external rents outside a firm’s boundaries. The paper concludes that HRM can assist in generating rents for firms and clusters more broadly when the function supports valuable interfirm relationships important for realising inter-firm advantages.

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The implementation of ‘good governance’ in Indonesia’s regional government sector became a central tenet in governance research following the introduction of the national code for governance in 2006. The code was originally drafted in 1999 as a response to the Asian financial crises and many cases of unearthed corruption, collusion, and nepotism. It was reviewed in 2001 and again in 2006 to incorporate relevant political, economical, and social developments. Even though the national code exists along with many regional government decrees on good governance, the extent of implementation of the tenets of good governance in Indonesia’s regional government is still questioned. Previous research on good governance implementation in Indonesian regional government (Mardiasmo, Barnes and Sakurai, 2008) identified differences in the nature and depth of implementation between various Indonesian regional governments. This paper analyses and extends this recent work and explores key factors that may impede the implementation and sustained application of governance practices across regional settings. The bureaucratic culture of Indonesian regional government is one that has been shaped for over approximately 30 years, in particular during that of the Soeharto regime. Previous research on this regime suggests a bureaucratic culture with a mix of positive and negative aspects. On one hand Soeharto’s regime resulted in strong development growth and strong economic fundamentals, resulting in Indonesia being recognised as one of the Asian economic tigers prior to the 1997 Asian financial crises. The financial crises however revealed a bureaucratic culture that was rife with corruption, collusion, and nepotism. Although subsequent Indonesian governments have been committed to eradicating entrenched practices it seems apparent that the culture is ingrained within the bureaucracy and eradication of it will take time. Informants from regional government agree with this observation, as they identify good governance as an innovative mechanism and to implement it will mean a deviation from the “old ways.” Thus there is a need for a “changed” mind set in order to implement sustained governance practices. Such an exercise has proven to be challenging so far, as there is “hidden” resistance from within the bureaucracy to change its ways. The inertia of such bureaucratic cultures forms a tension against the opportunity for the implementation of good governance. From this context an emergent finding is the existence of a ‘bureaucratic generation gap’ as an impeding variable to enhanced and more efficient implementation of governance systems. It was found that after the Asian financial crises the Indonesian government (both at national and regional level) drew upon a wider human resources pool to fill government positions – including entrants from academia, the private sector, international institutions, foreign nationals and new graduates. It suggested that this change in human capital within government is at the core of this ‘inter-generational divide.’ This divergence is exemplified, at one extreme, by [older] bureaucrats who have been in-position for long periods of time serving during the extended Soeharto regime. The “new” bureaucrats have only sat in their positions since the end of Asian financial crisis and did not serve during Soeharto’s regime. It is argued that the existence of this generation gap and associated aspects of organisational culture have significantly impeded modernising governance practices across regional Indonesia. This paper examines the experiences of government employees in five Indonesian regions: Solok, Padang, Gorontalo, Bali, and Jakarta. Each regional government is examined using a mixed methodology comprising of on-site observation, document analysis, and iterative semi-structured interviewing. Drawing from the experiences of five regional governments in implementing good governance this paper seeks to better understand the causal contexts of variable implementation governance practices and to suggest enhancements to the development of policies for sustainable inter-generational change in governance practice across regional government settings.