Isometric Sliced Inverse Regression for Nonlinear Manifolds Learning

[[abstract]]Sliced inverse regression (SIR) was developed to find effective linear dimension-reduction directions for exploring the intrinsic structure of the high-dimensional data. In this study, we present isometric SIR for nonlinear dimension reduction, which is a hybrid of the SIR method using the geodesic distance approximation. First, the proposed method computes the isometric distance between data points; the resulting distance matrix is then sliced according to K-means clustering results, and the classical SIR algorithm is applied. We show that the isometric SIR (ISOSIR) can reveal the geometric structure of a nonlinear manifold dataset (e.g., the Swiss roll). We report and discuss this novel method in comparison to several existing dimension-reduction techniques for data visualization and classification problems. The results show that ISOSIR is a promising nonlinear feature extractor for classification applications.[[incitationindex]]SCI[[booktype]]紙本[[booktype]]電子

Do we really care about absorbed radiation dose?

info:eu-repo/semantics/publishe

Sorting out Neighbourhood Effects Using Sibling Data

Previous research has reported evidence of intergenerational transmission of both neighbourhood status and social and economic outcomes later in life; parents influence where their children live as adults and how well they do later in life in terms of their income. However, interactions between the individual, the childhood family and neighbourhood context and the neighbourhood experiences after leaving the parental home are often overlooked which might bias estimates of neighbourhood effects. It is likely that part of the effects attributed to neighbourhoods, are actually effects of the family in which someone was brought up. This study uses a sibling design to disentangle family and neighbourhood effects on income, and synthetic sibling pairs are used as a control group. The sibling design allows us to separate the effects of childhood family and neighbourhood contexts, but also between childhood neighbourhood effects and effects of the adult neighbourhood experiences. Using data from Swedish registers we show that the neighbourhood effect from both childhood and adult neighbourhood exposure is biased upwards by the influence of the family context. This leads to the conclusion that part of what appeared to be a neighbourhood effect was in fact a lasting family effect. Interestingly, we find that there is a long lasting effect of the family context on income later in life, and that this effect is strong regardless the individual neighbourhood pathway later in life

Oxygen/steam gasification of wood

Yields from fixed-bed gasification of stoker fuel, pressed planar shavings, are presented for air/steam operation and oxygen/steam operation at four different compositions. The wood carbon distributes between gas products and liquid products in the respective ranges of 75 to 80 wt% and 20 to 25 wt%. The cold gas efficiencies, defined as the combustible energy in the gas divided by the heat of combustion of the wood, were 60% for operation with an air-to-steam weight ratio of 10, 52%, 61%, 59%, and 52% for operation with oxygen-to-steam weight ratios of 1/2, 1, 2, and 4 respectively. The other energy inputs to the system are less than the energy output in tar products so that the above efficiencies are about the same as the overall efficiencies. Concentrations of the gas at various heights in the fixed bed are presented. Conclusions about the height of the various zones can be inferred. Temperature profiles are also presented. Stoker fuel was used instead of wood chips because its bulk density was greater by a factor of 4. Limitations on the maximum volumetric input rate were such that only 50 lb/hr of wood chips could be added. Since gasification rates exceeded this amount, stoker fuel was used. Rates for stoker fuel gasification are presented for the different conditions. The results indicate that the maximum weight fraction of methanol from dry wood is 0.45 at an oxygen-to-steam weight ratio of 1 with reforming of the methane in the product gas, or a yield of 135 gallons of methanol per ton of dry wood. The maximum methane yield is obtained at the same oxygen-to-steam weight ratio of 1 and is 8600 scf/dry ton (270 NM/sup 3//dry MT)

Three Generations of Intergenerational Transmission of Neighbourhood Context

The literature on intergenerational contextual mobility has shown that neighbourhood status is partly "inherited" from parents to children where children who spend their childhood in deprived neighbourhoods are more likely to live in such neighbourhoods also as adults. It has been suggested that such transmission of neighbourhood status also is relevant from multiple generation approach. To our knowledge, however, this has only been confirmed by simulations and not empirical research. This study uses actual empirical data covering 25 years and the full Swedish population to investigate intergenerational similarities in neighbourhood status of three generations of Swedish women. Findings suggest that the neighbourhood environments of Swedish women are correlated with the neighbourhood statuses of their mothers and, to some extent, grandmothers. We also find an effect of distance where intergenerational transmission is stronger for those remaining close. Whereas women whose mothers and grandmothers live in high-income areas benefit from staying close, women whose mothers and grandmothers live in low-income areas do better if they live further away. These results are robust over two different analytical strategies – comparing neighbourhood status of the three generations at similar ages and at the same point in time – and two different spatial scales. We argue that the finding of such effects in (relatively egalitarian) Sweden implies that similar, and possibly stronger, patterns are likely to exist in other countries as well.OLD Urban Renewal and Housin

Experienced and Inherited Disadvantage: A Longitudinal Study of Early Adulthood Neighbourhood Careers of Siblings

Longer term exposure to high poverty neighbourhoods can affect individual socio-economic outcomes later in life. Previous research has shown strong path dependence in individual neighbourhood histories. A growing literature shows that the neighbourhood histories of people is linked to the neighbourhoods of their childhood and parental characteristics. To better understand intergenerational transmission of living in deprived neighbourhoods it is important to distinguish between inherited disadvantage (socio-economic position) and contextual disadvantage (environmental context in which children grow up). The objective of this paper is to come to a better understanding of the effects of inherited and contextual disadvantage on the neighbourhood careers of children once they have left the parental home. We use a quasi-experimental family design exploiting sibling relationships, including real sibling pairs, and "synthetic siblings" who are used as a control group. Using rich register data from Sweden we find that real siblings live more similar lives in terms of neighbourhood experiences during their independent residential career than synthetic sibling pairs. This difference reduces over time. Real siblings are still less different than synthetic pairs but the difference gets smaller with time, indicating a quicker attenuation of the family effect on residential outcomes than the neighbourhood effectOLD Urban Renewal and Housin

Inherited and Spatial Disadvantages: A Longitudinal Study of Early Adult Neighborhood Careers of Siblings

Understanding how inequalities are transmitted through generations and restrict upward spatial mobility has long been a concern of geographic research. Previous research has identified that the neighborhood in which someone grows up is highly predictive of the type of neighborhood he or she will live in as an independent adult. What remains largely unknown is the relative contribution of geography compared to the contribution of the family context in forming these individual life outcomes. The aim of this article is to better understand the role of the spatial–temporal contexts of individuals in shaping later life outcomes, by distinguishing between inherited disadvantage (socioeconomic position) and spatial disadvantage (the environmental context in which children grow up). We use a sibling design to analyze the neighborhood careers of adults after they have left the parental home, separating out the roles of the family from that of the neighborhood in determining residential careers. We employ rich Swedish Register data to construct a quasi-experimental family design to analyze residential outcomes for sibling pairs and contrast real siblings against a control group of “contextual siblings.” We find that real siblings live more similar lives in terms of neighborhood experiences during their independent residential careers than contextual sibling pairs but that this difference decreases over time. The results show the importance of geography, revealing long-lasting stickiness of spatial–temporal contexts of childhood.Urban Studie