Karl Küpfmüller, 1928: an early time-domain, closed-loop, stability criterion

Karl Küpfmüller was a German engineer who worked for eight years during the 1920s at Siemens & Halske in Berlin. During that time he carried out fundamental work on telegraphy and telephony, network theory, and the systems theory of electrical signal transmission. Like his contemporary in the US, Harry Nyquist, he derived fundamental results in information transmission and closed-loop modelling. In contrast to Nyquist, though, his name is not well-known in the English-speaking world. Indeed, little has appeared in English about him or his work – although his pioneering results in systems theory informed later American work, particularly through the contributions of Ernst Guillemin, a prolific writer of highly influential student texts and a great engineering educator at MIT, who was well-acquainted with the ideas of Küpfmüller (and other German electrical engineers)

Circular, No. 2

The information in this circular is intended for the use of settlers and homesteaders in Alaska who are interested in the more general growing of hardy flowering bulbs in the Territory. Alaska is very poor in native ornamental plants, and although the Alaska agricultural experiment stations do not specialize in flower growing, the Sitka station in 1923 began -an experiment which was later extended to the stations in the interior, to determine the possibility of growing bulbous plants in the Territory. The experiment has demonstrated that hardy flowering bulbs, including narcissus, tulips, English iris, gladiolus, the Regal lily, and hyacinths can be propagated on a commercial scale in Alaska. Lovers of these beautiful flowers should grow their own bulbs so far as possible, as some varieties can no longer be obtained in commercial quantities from foreign countries on account of the risk of introducing pests. Narcissus bulbs, shipped interstate by American growers, are required by a Federal quarantine to be inspected and certified to be free from pests and diseases, and certain States have placed similar restrictions on the sale of other kinds of bulbs.Narcissus: Forcing daffodils, Varieties -- Tulips: Varieties -- English iris: Gladiolus -- The Regal lily -- Tests in the interior -- General cultural directions -- Dutch method of planting -- Bibliograph

Automatic bandwidth selection for circular density estimation

Given angular data θ1,…,θn[0,2π) a common objective is to estimate the density. In case that a kernel estimator is used, bandwidth selection is crucial to the performance. A “plug-in rule” for the bandwidth, which is based on the concentration of a reference density, namely, the von Mises distribution is obtained. It is seen that this is equivalent to the usual Euclidean plug-in rule in the case where the concentration becomes large. In case that the concentration parameter is unknown, alternative methods are explored which are intended to be robust to departures from the reference density. Simulations indicate that “wrapped estimators” can perform well in this context. The methods are applied to a real bivariate dataset concerning protein structure

A great disappearing act: the electronic analogue computer

One historian of technology has called the analogue computer 'one of the great disappearing acts of the Twentieth Century'. This paper will look briefly at the origins, development and decline of the electronic analogue computer .

ICT support at the British Open University for student projects at a distance

In recent years the British Open University has been providing increasing ICT support to distance learners carrying out projects within the Faculty of Technology and elsewhere in the University. This paper reports briefly on three generic research tools ..

Circular, No. 1

Later editions and revisions included.This circular is designed to give prospective settlers in Alaska, and particularly homesteaders, information on subjects which will be of more or less vital interest to them. It is designed also to call their attention to many factors in the situation on which they should be informed before settling in a new and comparatively little-known territory.Climate: Coast region, Interior climate -- Agricultural areas: Character of the land, The soil -- Where to locate -- How to obtain a farm -- Transportation -- The chances for work and wages paid -- Cost of living -- What crops can be grown -- Live stock: The brown bear -- General information: Population, Judicial divisions, Land districts, National Forests, Telegraph and cable lines, Railroads, Schools, Game laws, Fisheries, Matanuska Valley -- Problems confronting early settlers in the Matanuska Valle

The prevalence of envelope wages in the Baltic Sea region

Purpose - The purpose of this paper is to evaluate in the Baltic Sea region the prevalence of an illegitimate wage arrangement whereby formal employers pay their formal employees both an official declared wage as well as a supplementary undeclared (envelope) wage. Design/methodology/approach - A 2007 Eurobarometer survey is reported that evaluates envelope wage practices in 27 European Union (EU) member states. This paper focuses upon the 4,031 face-to-face interviews conducted in four countries from the Baltic Sea region that are now member states of the EU, namely Estonia, Latvia, Lithuania and Poland. Findings - Some one in eight formal employees in these four countries from the Baltic Sea region received an undeclared "envelope" wage from their formal employer during the past 12 months which on average amounted to 45 per cent of their gross wage packet. Although this practice is concentrated in smaller businesses, the construction industry, and amongst younger people, manual workers and lower income groups in these four countries, it is by no means confined to specific pockets of the economic landscape. Rather, it exists throughout these countries in all business types and employee groups. Research limitations/implications - The existence and commonality of envelope wages reveals the need to transcend the dichotomous depiction of formal and informal jobs as always separate and discrete and to recognise how they can be inextricably interwoven. Practical implications - This paper outlines a range of potential policy measures for tack-ling envelope wages and calls for their piloting and evaluation. Originality/value - The first cross-national evaluation of the incidence and nature of envelope wages in the Baltic Sea region and what needs to be done to tackle this practice

Conjoined Events

Many existing synchronous message-passing systems support choice: engaging in one event XOR another. This paper introduces the AND operator that allows a process to engage in multiple events together (one AND one more AND another; all conjoined), engaging in each event only if it can atomically engage in all the conjoined events. We demonstrate using several examples that this operator supports new, more ?exible models of programming. We show that the AND operator allows the behaviour of processes to be expressed in local rules rather than system-wide constructs. We give an optimised implementation of the AND operator and explore the performance effect on standard communications of supporting this new operator

Agricultural entrepreneurship and sustainability - is it a good or bad fit?

In today’s Dutch agriculture emphasis is put on entrepreneurship, social responsibility and sustainability. But do these fit together? In economic theories entrepreneurs are seen as movers of the markets, seekers of profit opportunities and innovators. Not all farmers however meet these conditions and if they do, there is no guarantee that this goes with socially responsible entrepreneurship and sustainability. In a sociological explorative study a multiform group of 20 pig and 21 dairy farmers – both male and female – were asked about their views on animal welfare and other features of sustainable farming. The group consisted of conventional, organic and free range farmers with different farming styles. Their farms varied in levels of scale, intensity, degree of specialization and participation in quality assurance schemes. In the indepth interviews, it became clear that the farmers focus on different aspects of sustainability and that multi-dimensional sustainability is not a self-evident aim for all farmers. An economically viable farm is important for all farmers, although farmers with idealist motives stress this aspect less than other farmers. Social sustainability at the level of the farm (work load and schedule, division of tasks, balance work/ family life/ social life) is accentuated by conventional farmers on large scaled specialized farms. At a higher level of social sustainability (fair trade, fair prices, poverty reduction), in particular organic and biodynamic farmers stress that farmers have to take the responsibility to contribute to social equity. The latter group puts also emphasis on their responsibility towards the ecosystem. They, for instance, focus on sustainable cattle, mineral management and nature and landscape conservation. The interviewed large scale conventional farmers on the other hand, see energy production as a potentially profitable option to contribute to ecological sustainability. This means that agricultural entrepreneurs do not ‘automatically’ take all aspects of sustainability – people, planet and profit – into account. Policy makers who think they can stimulate sustainable agriculture by promoting agricultural entrepreneurship should be aware of this

Auto-Mobiles: Optimised Message-Passing

Some message-passing concurrent systems, such as occam 2, prohibit aliasing of data objects. Communicated data must thus be copied, which can be time-intensive for large data packets such as video frames. We introduce automatic mobility, a compiler optimisation that performs communications by reference and deduces when these communications can be performed without copying. We discuss bounds for speed-up and memory use, and benchmark the automatic mobility optimisation. We show that in the best case it can transform an operation from being linear with respect to packet size into constant-time