A simple algorithm for the adaptation of scores and power behavior of the corresponding rank test

The purpose of this paper is twofold:On one hand we want to give a very simple algorithm for evaluating a special rank estimator of the type given in Behnen, Neuhaus, and Ruymgaart (1983) for the approximate optimal choice of the scores-generating function of a two-sample linear rank test for the general testing problem H_o:F=G versus H₁:F ≤ G, F ≠ G, in order to demonstrate that the corresponding adaptive rank statistic is simple enough for practical applications. On the other hand we prove the asymptotic normality of the adaptive rank statistic under H (leading to approximate critical values) and demonstrate the adaptive behavior of the corresponding rank test by a Monte Carlo power simulation for sample sizes as low as m=10, n=10.     

On the Ghoudi,Khoudraji, and Rivest test for extreme‐value dependence

Ghoudi, Khoudraji & Rivest [The Canadian Journal of Statistics 1998;26:187–197] showed how to test whether the dependence structure of a pair of continuous random variables is characterized by an extreme‐value copula. The test is based on a U‐statistic whose finite‐ and large‐sample variance are determined by the present authors. They propose estimates of this variance which they compare to the jackknife estimate of Ghoudi, Khoudraji & Rivest ( 1998 ) through simulations. They study the finite‐sample and asymptotic power of the test under various alternatives. They illustrate their approach using financial and geological data. The Canadian Journal of Statistics © 2009 Statistical Society of Canada     

Infant Perception of Surface Texture and Relative Height as Distance Information: A Preferential‐Reaching Study

Two preferential‐reaching experiments explored 5‐ and 7‐month‐olds’ sensitivity to pictorial depth cues. In the first experiment, infants viewed a display in which texture gradients, linear perspective of the surface contours, and relative height in the visual field provided information that two objects were at different distances. Five‐ and 7‐month‐old infants reached preferentially for the apparently nearer object under monocular but not binocular viewing conditions, indicating that infants in both age groups respond to pictorial depth cues. In the second experiment, texture gradients and linear perspective of the surface contours were eliminated from the experimental display, making relative height the sole pictorial depth cue. Seven‐month‐olds again reached more often for the apparently nearer object under monocular, but not binocular viewing conditions. By contrast, the 5‐month‐olds’ reaching behavior did not differ between viewing conditions. These results indicate that 7‐month‐olds respond to the depth cue of relative height but provide no evidence of responsiveness to relative height in 5‐month‐olds. Both age groups responded more consistently to pictorial depth in Experiment 1 than in Experiment 2.     

On vertex-parity edge-colorings

A vertex signature \(\pi \) of a finite graph G is any mapping \(\pi \,{:}\,V(G)\rightarrow \{0,1\}\). An edge-coloring of G is said to be vertex-parity for the pair \((G,\pi )\) if for every vertex v each color used on the edges incident to v appears in parity accordance with \(\pi \), i.e. an even or odd number of times depending on whether \(\pi (v)\) equals 0 or 1, respectively. The minimum number of colors for which \((G,\pi )\) admits such an edge-coloring is denoted by \(\chi '_p(G,\pi )\). We characterize the existence and prove that \(\chi '_p(G,\pi )\) is at most 6. Furthermore, we give a structural characterization of the pairs \((G,\pi )\) for which \(\chi '_p(G,\pi )=5\) and \(\chi '_p(G,\pi )=6\). In the last part of the paper, we consider a weaker version of the coloring, where it suffices that at every vertex, at least one color appears in parity accordance with \(\pi \). We show that the corresponding chromatic index is at most 3 and give a complete characterization for it.     

Broadcasting multiple messages in the 1-in port model in optimal time

In the 1-in port model, every vertex of a synchronous network can receive at most one message in each time unit. We consider simultaneous broadcasting of multiple messages from the same source or from distinct sources in such networks with an additional restriction that every received message can be sent out to neighbors only in the next time unit and never to already informed vertex. We use a general concept of level-disjoint partitions developed for this scenario. Here we introduce a subgraph extension technique for efficient spreading information within this concept. Surprisingly, this approach with so called biwheels leads to simultaneous broadcasting of optimal number of messages on a wide class of graphs in optimal time. In particular, we provide tight results for bipartite tori, meshes, hypercubes, Knödel graphs, circulant graphs. We also propose several open problems and conjectures.     

Uncovering CSR meaning networks: A cross-national comparison of Turkey and Slovenia

This study addressed an important question about the meaning of corporate social responsibility (CSR), and how it is measured. Based on a comparison of the meaning networks of CSR in two countries with fundamentally different cultural and socioeconomic backgrounds, we argue that there is a need for an institutional perspective when studying CSR associations and expectations in a particular society. Thus empirical study involved the use of three methods the word-association technique, social network analysis, and blockmodeling using Pajek software; to provide deep insight into the structure of CSR associations. The findings suggest that the two societies have diverse collective cognitive structures regarding CSR. In Turkey, the philanthropic understanding of CSR is highly dominant, while the Slovenian social meaning of CSR is multidimensional. The findings point to the social construction of the concept of CSR with implications both for academic research and practice.     

Ties,sites and irregularities: pitfalls and benefits in using respondent-driven sampling for surveying a homeless population

Respondent-driven sampling (RDS) is a survey method for hidden populations and, as such, it offers a suitable approach for sampling the homeless. Surprisingly, the practical use of RDS in surveying homeless populations has only sporadically been described in the professional literature so far, and the specifics of using RDS for sampling this group have not been reflected in depth. The goal of the article is to investigate how three specific concerns, namely the transitional character of social ties among the homeless, problems with locating the interview site, and the irregular use of coupons, affect the sampling process. The findings of the article are based on experience using RDS for creating two independent samples of homeless persons in two Czech cities. Worries of poor referral effectiveness were disproved, but poor validity of the network size indicator, tendency towards irregular use of coupons, and negative effects arising from selecting service centres for the homeless as survey sites were confirmed.     

Exploring the value of involving experts-by-experience in social work research: experiences from Slovenia and the UK

The evidence base for the methodological validity of conducting participatory research is becoming established. This article reviews the experiences of two researchers undertaking Ph.D. studies in Slovenia and UK, respectively, and considers the value of involving service users and carers in social work research. The Slovenian research involved user-researchers who developed research tools and undertook qualitative research. The first author explores the co-researchers’ impact on the research process and its outcomes, identifying both individual and collective empowerment of the co-researchers. The English study involved people from diverse backgrounds, who developed a recovery training programme for carers of people with schizophrenia. The second author describes how the steering group, and the carers who participated in the programme were impacted by the research process and experienced a sense of empowerment and how they influenced the development of new knowledge through the reflexive cycle. The authors draw out the commonalities and differences in our research that add to the existing evidence base supporting the development of participatory inquiry. We conclude by affirming the value of user participation in research in leading to the empowerment of users, the development of new research perspectives, and in contributing to theory in social work research and practice.     

The humanitarian crisis of migration versus the crisis of humanitarianism: current dimensions and challenges for social work practice*

People who comprise today’s mass migrations are the embodiment of an increasingly hurtful planetary interconnectedness between towering inequalities and hegemonies and human lives. The humanitarian crisis has turned into a fundamental crisis of humanitarianism. The crisis of humanitarianism builds up by the state borders increasingly militarized, equipped with one manner or the other of securitization, seeking to externalize the migrating people. Further, the governments seek to institutionalize and spatially segregate the people, whilst the resident population is subjected to programmatic inciting of racism and xenophobia. Racist eurocentrism pictures the West as democratic, and migrant people as non-democratic; it does not distinguish between individuals and political regimes; does not take into consideration the emergency situations from which they flee: it is thus a form of armed humanitarianism. The Balkan countries which were part of the Balkan Refugee route have become prison countries, custodians of the EU border. They conserve the image of the dangerous Balkans and consolidate Balkanism. A complex social work response includes individual, institutional, curricular, and research levels of reflection and intervention.     

Cross-entropy method for estimation of posterior expectation in Bayesian VAR models

In this article, an importance sampling (IS) method for the posterior expectation of a non linear function in a Bayesian vector autoregressive (VAR) model is developed. Most Bayesian inference problems involve the evaluation of the expectation of a function of interest, usually a non linear function of the model parameters, under the posterior distribution. Non linear functions in Bayesian VAR setting are difficult to estimate and usually require numerical methods for their evaluation. A weighted IS estimator is used for the evaluation of the posterior expectation. With the cross-entropy (CE) approach, the IS density is chosen from a specified family of densities such that the CE distance or the Kullback–Leibler divergence between the optimal IS density and the importance density is minimal. The performance of the proposed algorithm is assessed in an iterated multistep forecasting of US macroeconomic time series.