The web proxy location problem in general tree of rings networks

The Web proxy location problem in general networks is an NP-hard problem. In this paper, we study the problem in networks showing a general tree of rings topology. We improve the results of the tree case in literature and get an exact algorithm with time complexity O(nhk), where n is the number of nodes in the tree, h is the height of the tree (the server is in the root of the tree), and k is the number of web proxies to be placed in the net. For the case of networks with a general tree of rings topology we present an exact algorithm with O(kn ²) time complexity.This research has been supported by NSF of China (No. 10371028) and the Educational Department grant of Zhejiang Province (No. 20030622).     

On Combining Wavelets Expansion and Sparse Linear Models for Regression on Metabolomic Data and Biomarker Selection

Wavelet thresholding of spectra has to be handled with care when the spectra are the predictors of a regression problem. Indeed, a blind thresholding of the signal followed by a regression method often leads to deteriorated predictions. The scope of this article is to show that sparse regression methods, applied in the wavelet domain, perform an automatic thresholding: the most relevant wavelet coefficients are selected to optimize the prediction of a given target of interest. This approach can be seen as a joint thresholding designed for a predictive purpose. The method is illustrated on a real world problem where metabolomic data are linked to poison ingestion. This example proves the usefulness of wavelet expansion and the good behavior of sparse and regularized methods. A comparison study is performed between the two-steps approach (wavelet thresholding and regression) and the one-step approach (selection of wavelet coefficients with a sparse regression). The comparison includes two types of wavelet bases, various thresholding methods, and various regression methods and is evaluated by calculating prediction performances. Information about the location of the most important features on the spectra was also obtained and used to identify the most relevant metabolites involved in the mice poisoning.     

Strukturelle Kränkungen als Thema im Coaching

In this article hurts in the workplace are discussed, which are not aggressions of one person against another person. Rather they are effects of structural conditions in organizations or effects of legal processes in societies. The author presents three case studies with examples of such hurts and she postulates, that the Coach has to reflect political conditions in his work.     

Einstellungen gegenüber ?lteren Besch?ftigten

The ??Beliefs About Older Workers Questionnaire?? (Hassell und Perrewe, Journal of Organizational Behavior 16(5):457?C468, 1995) was developed to analyze beliefs about older workers and comprises 27 questions. In this article we present a German version of the ??Beliefs About Older Workers Questionnaire??. We design two versions of the questionnaire, one for beliefs about older female and one for beliefs about older male workers. We report results of a study in which the German questionnaires for male and female workers were administered and tested for the first time. We observed neutral to slightly negative beliefs about older workers. The study identified impacts of the gender of subjects and objects on beliefs about older workers. However, these were rather small. Organizations could profit from instruments like the presented questionnaire to identify age stereotypes and the need for accordant measures. Repeated application of the questionnaire or simultaneous application in other organizational units or organizations would enable organizations to evaluate applied measures or to learn from good practice in other organizational units or organizations.     

Warum und wodurch Coaching wirkt

The contribution reviews the state oft the art of the research on general success factors in the coaching process. Research in the field of psychotherapy on basic variables of client centered counseling and general therapeutic change mechanisms set an example. Results of first studies on these and modified factors show that the coaching outcome depends on observed esteem and emotional support by the coach, resource activation and support of transfer into practice. Process analysis of nonverbal interactions between coach and client demonstrate that goal attainment influence goal attainment. Finally, the paper focuses on limitations, of the studies, scientific and practical conclusions as well as future perspectives.     

Exclusion and vulnerability on public transit: experiences of transit dependent riders in Portland,Oregon

In urban areas, the inequitable distribution of transit systems and services has been shown to reproduce safety and environmental risks – potentially exacerbating preexisting inequities. Thus, how vulnerable populations access and utilize public transportation is of critical concern to urban scholars. This paper utilizes focus group data to explore how transit-dependent (particularly low-income) riders engage with the public transit system in Portland, Oregon. We illustrate specific ways in which transit-dependent riders experience marginalization and exclusion. We find that certain groups, particularly mothers with young children and those with disabilities are not well served by a public infrastructure oriented toward an ‘ideal rider’ who is an economically stable, able-bodied, white, male commuter. We conclude that a public infrastructure meant to serve all riders equitably, yet which fails to consider the unique experiences of marginalized transit users risks further amplifying existing social vulnerabilities and reinforcing gender, racial, and class inequalities.