Non-reduced optimal observers for time-varying linear systems

A method is presented for constructing a nonreduced observer for a finite dimensional linear system. The systems considered are nth order, time-invariant or time-varying forced linear systems which are assumed to be bounded and uniformly completely state reconstructible. The observer dynamics are derived from an optimal estimation formulation which is related to the concept of observability. The cost functional used in this formulation includes a parameter which determines the relative weighting of the system output and the estimate of the initial system state. The result is a practical method of estimating the state of a linear system from noiseless measurements of the input and output. The results are also of theoretical significance in that a direct connection between reconstructibility and the existence of observers is established.     

Measuring the unmeasurable: a country's non-R&D expenditure on product and service innovation

Knowledge about non-R&D innovation expenditure, such as patenting and licensing, design, trial production, tooling-up, manpower training, market research and investment in fixed assets, is extremely sparse and questions about the latter were very poorly answered in the recent Community Innovation Survey (CIS). Using information regarding the quality of replies, we reach a tentative national estimate of 1992 innovation expenditure for all manufacturing and service industries in the Netherlands. Expenditure on product-related R&D represents about one quarter of total product (and service) innovation expenditure. Roughly half of the latter consists of investment in fixed assets, the latter being more important in services than in manufacturing.     

全球疫情技治的文化比较

新冠疫情全球爆发和防控,彰显科学技术之运用在应对公共卫生危机中的重要作用.不同国家和地区在疫情应对中的差别,反映出在技术文化尤其是技术治理方面的差异,包括技术范式、技术实践和疫期生活等方面的不同.同时,在意识形态和政治差异背景下,世界日益走向全球性技术治理,对此需要更深入的研究和反思.本文主要以中国、德国和美国的情况为例,比较世界不同国家和地区运用科技应对疫情的差异,理解世界技术文化的多元性,以期帮助提升各国技术治理的水平.     

What Makes for Great Data Journalism?

This study examines the quality of winners and finalists in major national and international data journalism awards. We completed a content analysis of data projects submitted by Canadian media to three journalism associations—the Online News Association, the Global Editors Network and the Canadian Association of Journalists—as far back as the first award in this category in 2012. Our research addresses how journalists executed what could be considered excellent data journalism. Our findings point to a lack of accepted standards regarding what is considered as excellence. The quality of the projects was limited by two key factors: the use of free online options such as Google Maps that were not easily customizable; and the number of practitioners who worked on the data projects largely within traditional journalism frameworks. The most used visual elements were dynamic maps, graphs and video. With respect to interactivity, all but one of the projects contained an interactive element. The most popular interaction techniques were inspection and filtering, considered entry-level techniques in the field of information visualization. These techniques suggest a need for collaborative interdisciplinary approaches to data journalism, and further study on the implications of tools such as Google Maps on practice.     

Parental expectations of children’s higher education participation in Australia

The role of parental expectations in determining children's higher education participation is important in understanding both participation and potential policy responses. Using a nationally representative longitudinal survey of Australian households, providing repeat observations on expectations for individual children, this study extends the literature in several respects. First, it examines the adaptation of parental expectations over a 4-year time frame. Second, it looks at how parental expectations for school children are associated with actual higher education outcomes in the future. Third, the longitudinal aspect of the dataset permits more robust analyses of factors that shape parental expectations. The findings indicate that parental expectations of their children's attendance at university are generally stable across time. Perceptions of children's academic achievement at school are shown to be the key influence in shaping parents' expectations, and behavioural issues at school adversely affect expectations. Australian parents from non-English-speaking backgrounds were more likely to form positive expectations of university participation by their children, consistent with studies from other countries. A more nuanced picture of the formation of expectations for sole-parent mothers is also presented. Positive effects of parental education and children's enrolment in a private school on parents' expectations, over and above any effect on school achievement, highlight these socioeconomic factors as potential causal channels for the intergenerational transmission of socioeconomic outcomes.     

The onset of deep recycling of supracrustal materials at the Paleo-Mesoarchean boundary

The recycling of supracrustal materials, and in particular hydrated rocks, has a profound impact on mantle composition and thus on the formation of continental crust, because water modifies the physical properties of lithological systems and the mechanisms of partial melting and fractional fractionation. On the modern Earth, plate tectonics offers an efficient mechanism for mass transport from the Earth''s surface to its interior, but how far this mechanism dates back in the Earth''s history is still uncertain. Here, we use zircon oxygen (O) isotopes to track recycling of supracrustal materials into the magma sources of early Archean igneous suites from the Kaapvaal Craton, southern Africa. The mean δ¹⁸O values of zircon from TTG (tonalite–trondhjemite–granodiorite) rocks abruptly increase at the Paleo-Mesoarchean boundary (ca. 3230 million years ago; Ma), from mantle zircon values of 5‰–6‰ to approaching 7.1‰, and this increase occurs in ≤3230 Ma rocks with elevated Dy/Yb ratios. The ¹⁸O enrichment is a unique signature of low-temperature water–rock interaction on the Earth''s surface. Because the later phase was emplaced into the same crustal level as the older one and TTG magmas would derive from melting processes in the garnet stability field (>40 km depth), we suggest that this evident shift in TTG zircon O isotopic compositions records the onset of recycling of the mafic oceanic crust that underwent seawater hydrothermal alteration at low temperature. The onset of the enhanced recycling of supracrustal materials may also have developed elsewhere in other Archean cratons and reflects a significant change in the tectonic realm during craton formation and stabilization, which may be important processes for the operation of plate tectonics on early Earth.