First encounters on Bethe Lattices and Cayley Trees

In this work we consider the first encounter problems between a fixed and/or mobile target A and a moving trap B on Bethe Lattices and Cayley trees. The survival probability (SP) of the target A on the both kinds of structures are analyzed analytically and compared. On Bethe Lattices, the results show that the fixed target will still prolong its survival time, whereas, on Cayley trees, there are some initial positions where the target should move to prolong its survival time. The mean first encounter time (MFET) for mobile target A is evaluated numerically and compared with the mean first passage time (MFPT) for the fixed target A. Different initial settings are addressed and clear boundaries are obtained. These findings are helpful for optimizing the strategy to prolong the survival time of the target or to speed up the search process on Cayley trees, in relation to the target's movement and the initial position configuration of the two walkers. We also present a new method, which uses a small amount of memory, for simulating random walks on Cayley trees.Comment: 25 pages, 11 figure

Measuring the stars and observing the less visible: Australia’s participation in the Astrographic Catalogue and Carte du Ciel

Australia’s 1887 decision to participate in a major international astronomical project to produce an Astrographic (Star) Catalogue and Carte du Ciel (Chart of the Sky) ultimately involved Adelaide, Sydney, Melbourne and Perth observatories. Participation in this project promised to bring international recognition of Australia’s capability in astronomy and access to the latest photographic technology and methods, within a network comprised of leading astronomers and observatories from around the globe. This was not a straightforward process; obtaining the resources required to successfully participate was fraught in terms of seeking support from governments that did not necessarily understand the significance of the projects, the lack of an appropriately trained workforce, and the sheer volume of work to catalogue the star-rich sky of the Southern Hemisphere. The challenges of participating in major and extensive international projects, during a period when astronomy within Australia wavered between state and federal control, were enormous. The techniques and technologies were not consolidated and often difficult to obtain, due to the impact of two world wars. Recessions and a major depression, along with colonial attitudes to science, made the resources required for progress at times unaffordable within meagre State Observatory budgets. The participating observatories have been examined through archival research to reveal not only the significance of this star catalogue to the development of astronomy in Australia, but the momentous and unacknowledged contribution made by women in its production. I have investigated the participation of seven women in the projects through in-depth interviews and primary sources, including log books of star positions and magnitudes and observation log books not previously recognised as their work. This thesis reveals the Astrographic Catalogue as pivotal to the introduction of women into paid astronomical work in Australia.«br /» The Astrographic Catalogue and Carte du Ciel are interrogated as products of colonialist ambitions to chart territory. Actor–network theory, centres of calculation and circulation models developed by sociology of science theorists, including Bruno Latour and Michel Callon, have been applied to analyse the control over the participating state observatories by colonial astronomy networks. My research has uncovered evidence of the interference of the Colonial Secretaries and Astronomers Royal, and the sometimes catastrophic impact of economic, social and political upheavals. This thesis argues that modernist ideals of automation and global standardisation provided momentum for the techniques of observation to change, and the eye of the astronomer was replaced by the eye of the human star measurer, predominantly women, who became the new point of contention at which individual variation occurred. I reveal that the involvement of women in Australia on the Astrographic Catalogue and Carte du Ciel was of greater significance than previously recognised; in addition, whilst they were restricted due to their gender, these women had agency in the scientific practice, workplace behaviour and employment conditions within the observatory. Furthermore, the creation of sex-specific roles in astronomy developed through the labour requirements of the large data sets for the Astrographic Catalogue, and the historical invisibility of women’s work in science, have had contemporary consequences for the status and participation of women in astronomy

Public policy alienation of public service workers: A conceptual framework

This paper theoretically examines identification problems with the implementation of public policies. When these identification problems occur, they might have significant impacts. For instance, the quality of the interaction between service workers and clients influence the effectiveness and legitimacy of public administration. the success of public policies for a great deal depends on the compliance and motivation of the service worker implementing them

Public policy alienation of public service workers

Nowadays, many public professionals face identification problems towards public policies they have to implement; that is, they experience policy alienation. This is troublesome, as for a proper implementation a minimal level of identification with the public policy is required. We use literature related to the identification problems of (public) service workers, for example Public Service Motivation (Perry, 2000), New Public Management (Pollitt & Bouckaert, 2004), technology (Zuboff, 2004) , street-level bureaucrats (Lipsky, 1980) and organization commitment (Steinhaus & Perry, 1996). But mainstream literature has not yet studied the problem of identification of the service worker with public policies. These disciplines will, however, be used to construct propositions for the identification problem. This paper seeks to fill this lacuna by using the concept of alienation, a concept originating from the sociology of work and organization. Literature from this discipline offers useful concepts for building our theoretical framework. All in all, the project offers a multidisciplinary approach, combining the research fields of public management, public policy sciences and the sociology of work and organization

Retraining Programs for Coal Workers in Transition: Lessons from Appalachia

The use of coal for energy in the United States is being pushed to historic lows for a number of reasons, including the ascent of natural gas as the fuel of choice, technological advancements, environmental regulations, mechanization of extraction and the rise of renewable sources of energy. Meanwhile, coal communities around the nation are left to grapple with the consequences of coal mine and power station closures, and consequent job losses. In response, the government, and some civil society organizations, have made available several retraining programs for unemployed coal workers. However, these initiatives have largely failed to attract and retain displaced workers in the coal mining regions. Helping coal country move forward has proved more difficult than anticipated, and this paper delves into the technical and practical aspects of some of the existing programs and organizations. The paper explored three case studies of retraining initiatives in the Appalachian region, which were created specifically to help former coal workers transition to a new sector. The research explores the effectiveness of Appalachian-born responses to the mining job crisis by comparing a selection of three case studies, and an analysis of the most successful elements is discussed

Learning by generation in computer science education

The use of generic and generative methods for the development and application of interactive educational software is a relatively unexplored area in industry and education. Advantages of generic and generative techniques are, among other things, the high degree of reusability of systems parts and the reduction of development costs. Furthermore, generative methods can be used for the development or realization of novel learning models. In this paper, we discuss such a learning model that propagates a new way of explorative learning in computer science education with the help of generators. A realization of this model represents the educational software GANIFA on the theory of generating finite automata from regular expressions. In addition to the educational system's description, we present an evaluation of this system.Facultad de Informátic