Portable random number generators

Computers are deterministic devices, and a computer-generated random number is a contradiction in terms. As a result, computer-generated pseudorandom numbers are fraught with peril for the unwary. We summarize much that is known about the most well-known pseudorandom number generators: congruential generators. We also provide machine-independent programs to implement the generators in any language that has 32-bit signed integers-for example C, C++, and FORTRAN. Based on an extensive search, we provide parameter values better than those previously available.Programming (Mathematics) ; Computers

Stress-Minimizing Orthogonal Layout of Data Flow Diagrams with Ports

We present a fundamentally different approach to orthogonal layout of data flow diagrams with ports. This is based on extending constrained stress majorization to cater for ports and flow layout. Because we are minimizing stress we are able to better display global structure, as measured by several criteria such as stress, edge-length variance, and aspect ratio. Compared to the layered approach, our layouts tend to exhibit symmetries, and eliminate inter-layer whitespace, making the diagrams more compact

When the Shoe is on the Other Foot: Experimental Evidence on Valuation Disparities

The method of elicitation has an important effect on valuations. We investigate the effect of perspective on decision makersâ?? elicited values. We conduct experimental sessions in which participants act as sellers or buyers and replicate the disparity between willingness to accept and willingness to pay: sellers want to collect more and buyers want to pay less. We conduct additional sessions in which endowed decision makers provide values that are used to determine a price at which anonymous others transact. In these sessions, decision makersâ?? experimental earnings are not affected by valuations, but rather determined by their endowment. Decision makers appear to consider their standing relative to anonymous others in providing valuations, i.e., decision makersâ?? endowments affect their valuations. The results indicate that the disparity between willingness to accept and willingness to pay disappears when decision makersâ?? endowment ensures that they are at least as well off as anonymous others.

When the shoe is on the other foot: experimental evidence on evaluation disparities

Research provides evidence that the method chosen to elicit value has an important effect on a person’s valuation. We hypothesize that role has a crucial effect on decision makers’ elicited values: Buyers prefer to pay less and sellers prefer to collect more. We conduct experimental sessions and replicate the disparity between willingness to pay and willingness to accept. We conduct additional sessions in which role is stripped away: Endowed decision makers provide values that are used to determine a price at which anonymous others transact. Importantly, decision makers’ earnings in the experiment are not affected by the elicited values, but the endowments influence decision makers’ valuations. Our findings suggest that decision makers consider their relative standing, in comparison to anonymous others, in providing valuations. The disparity between willingness to pay and willingness to accept disappears when decision makers’ endowments ensure that they are at least as well off as other participants.

The social security rights of older international migrants in the European Union

Europe is now home to a significant and diverse population of older international migrants. Social and demographic changes have forced the issue of social security in old age onto the European social policy agenda in the last decade. In spite of an increased interest in the financial well-being of older people, many retired international migrants who are legally resident in the European Union face structured disadvantages. Four linked factors are of particular importance in shaping the pension rights and levels of financial provision available to individual older migrants: migration history, socio-legal status, past relationship to the paid labour market, and location within a particular EU Member State. Building on a typology of older migrants, the paper outlines the ways in which policy at both the European Union and Member State levels serves to diminish rather than enhance the social security rights of certain older international migrants

Integrating Dynamics and Wear Modelling to Predict Railway Wheel Profile Evolution

The aim of the work described was to predict wheel profile evolution by integrating multi-body dynamics simulations of a wheelset with a wear model. The wear modelling approach is based on a wear index commonly used in rail wear predictions. This assumes wear is proportional to Tγ, where T is tractive force and γ is slip at the wheel/rail interface. Twin disc testing of rail and wheel materials was carried out to generate wear coefficients for use in the model. The modelling code is interfaced with ADAMS/Rail, which produces multi-body dynamics simulations of a railway wheelset and contact conditions at the wheel/rail interface. Simplified theory of rolling contact is used to discretise the contact patches produced by ADAMS/Rail and calculate traction and slip within each. The wear model combines the simplified theory of rolling contact, ADAMS/Rail output and the wear coefficients to predict the wear and hence the change of wheel profile for given track layouts

Drawing Graphs within Restricted Area

We study the problem of selecting a maximum-weight subgraph of a given graph such that the subgraph can be drawn within a prescribed drawing area subject to given non-uniform vertex sizes. We develop and analyze heuristics both for the general (undirected) case and for the use case of (directed) calculation graphs which are used to analyze the typical mistakes that high school students make when transforming mathematical expressions in the process of calculating, for example, sums of fractions

Search for Sterile Neutrinos with a Radioactive Source at Daya Bay

The far site detector complex of the Daya Bay reactor experiment is proposed as a location to search for sterile neutrinos with > eV mass. Antineutrinos from a 500 kCi 144Ce-144Pr beta-decay source (DeltaQ=2.996 MeV) would be detected by four identical 20-ton antineutrino targets. The site layout allows flexible source placement; several specific source locations are discussed. In one year, the 3+1 sterile neutrino hypothesis can be tested at essentially the full suggested range of the parameters Delta m^2_{new} and sin^22theta_{new} (90% C.L.). The backgrounds from six nuclear reactors at >1.6 km distance are shown to be manageable. Advantages of performing the experiment at the Daya Bay far site are described

Response to Kamath et al 'A syncretic approach can yield dividends'

We welcome the response from Kamath et al. and their insight into the issues and culture within medicine in India, and their thoughts about how to address these issues. We also agree that a drama-based approach is not sufficient on its own to deal with entrenched power issues which affect students adversely. As we have indicated, we believe “a multipronged approach is needed to generate systemic change.” These authors similarly advocate that student mistreatment be dealt with “in a comprehensive manner” including a ‘grievance redressal system’ and other measures to withhold accreditation where there are issues of abuse of power. Nevertheless, we note that Kamath et al. have responded positively to our approach—as a part of that mix—and it would be of great interest to see whether drama-based workshops could support medical students developing embodied acting skills in their institution and whether they may have similar transformative effects. We’d like to refer the authors to an excellent Medical Humanities paper we referenced that outlined drama-based activities in medical education in India: Gupta S, Singh S. Confluence: understanding medical humanities through street theatre. Medical Humanities. 2011;37(2):127-128. Despite the above article, the authors note that medical education in India has not embraced the medical humanities. We would draw a distinction within the medical humanities between activities which are primarily studious (reading literature, studying medical history) and workshops that are based on participative and embodied activity. Our experience has indicated the effectiveness of drama-based workshops in addressing both the cognitive and emotive aspects of harmful practices and we believe that it is the embodied nature of acting skills workshops that is transformative