Inductive transfer for learning Bayesian networks

In several domains it is common to have data from different, but closely related problems. For instance, in manufacturing, many products follow the same industrial process but with different conditions; or in industrial diagnosis, where there is equipment with similar specifications. In these cases it is common to have plenty of data for some scenarios but very little for others. In order to learn accurate models for rare cases, it is desirable to use data and knowledge from similar cases; a technique known as transfer learning. In this paper we propose an inductive transfer learning method for Bayesian networks, that considers both structure and parameter learning. For structure learning we use conditional independence tests, by combining measures from the target task with those obtained from one or more auxiliary tasks, using a novel weighted sum of the conditional independence measures. For parameter learning, we propose two variants of the linear pool for probability aggregation, combining the probability estimates from the target task with those from the auxiliary tasks. To validate our approach, we used three Bayesian networks models that are commonly used for evaluating learning techniques, and generated variants of each model by changing the structure as well as the parameters. We then learned one of the variants with a small dataset and combined it with information from the other variants. The experimental results show a significant improvement in terms of structure and parameters when we transfer knowledge from similar tasks. We also evaluated the method with real-world data from a manufacturing process considering several products, obtaining an improvement in terms of log-likelihood between the data and the model when we do transfer learning from related products.     

The effects of socioeconomic status, race, and parenting on language development in early childhood.

The authors examined the associations between socioeconomic status (SES), race, maternal sensitivity, and maternal negative-intrusive behaviors and language development in a sample selected to reduce the typical confound between race and SES (n = 146). Mother–child interactions were observed at 12 and 24 months (coded by randomly assigned African American and European American coders); language abilities were assessed at 18, 24, 30, and 36 months. For receptive language, race was associated with ability level, and maternal sensitivity and negative-intrusive parenting were related to rate of growth. For expressive communication, race, SES, and maternal sensitivity were associated with rate of growth; race moderated the association between negative-intrusive parenting and rate of growth such that the relation was weaker for African American than for European American children. The results highlight the importance of sensitive parenting and suggest that the association between negative-intrusive parenting and language development may depend upon family context. Future work is needed concerning the race differences found, including examining associations with other demographic factors and variations in language input experienced by children, using culturally and racially validated indices of language development. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

国际放射防护委员会新建议书准备工作的进展

国际放射防护委员会（ＩＣＲＰ）使用的低水平电离辐射照射的致癌危险已经受到了挑战,有人说它太高,同时也有人说它太低。本文说明,流行病学的证据总是在低剂量受到限制,因此,为了评价生物学危险,理解致癌的细胞机制就愈加重要。从而,通过分析,找出为什么会对ＩＣＲＰ提出挑战,特别是对线性无阈响应模型提出挑战的原因。通过对这些问题的认真考虑,ＩＣＲＰ主委员会现正研究一种经修改的简化方法,它是建筑在着眼于个体的哲     

Development or a Korotkov Sound Processor for Automatic Identification of Auscultatory Events?Part II Decision Logic Specifications and Operational Verification

An electronic Korotkov sound processor has been developed for the automatic identification of the systolic and diastolic Korotkov sound transitions. This processor incorporates separate circuitry for systolic and diastolic decisions, each with its own defined preprocessing bandpass filter. The decision logic is designed to provide amplitude normalization both within and between subjects, and physiological testing was performed, to optimize the required critical-decision logic parameters. The accuracy of this processor design was evaluated using 32 normal subjects at rest and under orthostatic and ergometric stress conditions. The processor was shown to be quite accurate in its identification of the auscultatory systolic or diastolic event for passive subject conditions; processor accuracy was reduced for subjects participating in ergometric stress.     

An invariant subspace‐based approach to the random eigenvalue problem of systems with clustered spectrum

The repeated or closely spaced eigenvalues and corresponding eigenvectors of a matrix are usually very sensitive to a perturbation of the matrix, which makes capturing the behavior of these eigenpairs very difficult. Similar difficulty is encountered in solving the random eigenvalue problem when a matrix with random elements has a set of clustered eigenvalues in its mean. In addition, the methods to solve the random eigenvalue problem often differ in characterizing the problem, which leads to different interpretations of the solution. Thus, the solutions obtained from different methods become mathematically incomparable. These two issues, the difficulty of solving and the non‐unique characterization, are addressed here. A different approach is used where instead of tracking a few individual eigenpairs, the corresponding invariant subspace is tracked. The spectral stochastic finite element method is used for analysis, where the polynomial chaos expansion is used to represent the random eigenvalues and eigenvectors. However, the main concept of tracking the invariant subspace remains mostly independent of any such representation. The approach is successfully implemented in response prediction of a system with repeated natural frequencies. It is found that tracking only an invariant subspace could be sufficient to build a modal‐based reduced‐order model of the system. Copyright © 2012 John Wiley & Sons, Ltd.     

Ultrananocrystalline Diamond-Coated Microporous Silicon Nitride Membranes for Medical Implant Applications

Ultrananocrystalline diamond (UNCD) exhibits excellent biological and mechanical properties, which make it an appropriate choice for promoting epidermal cell migration on the surfaces of percutaneous implants. We deposited a ~150 nm thick UNCD film on a microporous silicon nitride membrane using microwave plasma chemical vapor deposition. Scanning electron microscopy and Raman spectroscopy were used to examine the pore structure and chemical bonding of this material, respectively. Growth of human epidermal keratinocytes on UNCD-coated microporous silicon nitride membranes and uncoated microporous silicon nitride membranes was compared using the 3-(4,5-dimethylthiazol-2-yl)2,5-diphenyltetrazolium bromide (MTT) assay. The results show that the UNCD coating did not significantly alter the viability of human epidermal keratinocytes, indicating potential use of this material for improving skin sealing around percutaneous implants.     

Researchers on the pier: Academics’ use of a local internet gateway

This paper describes the establishment of an Internet gateway local to the University of Sussex, firstly as a Gopher and more recently as a World Wide Web server. There follows an account of a project currently underway to assess the practical value of Internet resources to research and the consequential training and support requirements. This assessment is planned to determine the value of a local gateway to academic researchers at Sussex and the roles specific to a local gateway that such comprehensive resources as Yahoo and BUBL cannot fulfil. The project is using an interview‐based methodology to gain an understanding of researchers’ views of Internet resource provision, and these interviews are being analysed with the help of the NUD*IST qualitative data analysis software package. The account is of research in progress, and hence does not conclude with the set of pragmatic policy proposals that forms its key objective. Instead, some indication is given of the broad early findings of the project     

Atmospheric correction over land for MERIS

A three-stage atmospheric correction is proposed for the Medium Resolution Imaging Spectrometer (MERIS) from a validated formulation of the signal. We correct first for the gaseous transmittance. Assuming the ozone correction is well defined, we illustrate the need to include a correction for water vapour continuum which covers most of the MERIS bands. The water vapour transmittance can be computed from the water vapour content obtained from a twoband ratio at 900nm and 890nm. We demonstrate that a direct association between the transmittance in a given band and the two band ratio is more accurate due to the removal of the coupling between absorption and scattering. Secondly, the Rayleigh correction depends on the barometric pressure determined here from a two band ratio method with the oxygen A band. Good accuracy is obtained for the pressure when accounting for the coupling between scattering and gas absorption, which mostly depends on the surface reflectance. The Rayleigh reflectance is computed from a Fourier series decomposition in which primary scattering is corrected for multiple scattering by a multiplicative factor which is derived from a polynomial regression versus the optical thickness. A similar formulation of the signal is proposed for the aerosol reflectances from 12 predefined aerosol models. The aerosol correction relies on a characterization of the aerosol over Dense Dark Vegetation for which an identification criteria is proposed along with standard reflectance values in the blue and in the red.     

Particle breakdown dynamics of heterogeneous foods during mastication: Peanuts embedded inside different food matrices

Heterogeneous foods are widely consumed but little is known about the dynamics of their breakdown during mastication. To investigate these dynamics the particle size and bolus mass at regular stages of the chewing sequence were investigated using a single subject, who was carefully selected according to strict mastication and dental criteria. A standardized volume of both a gelatine gel and chocolate matrix containing roasted peanuts was chewed and expectorated after a specified number of chews or at the point of swallowing. The mass of various components of the bolus was determined along with peanut particle parameters (d₅₀, broadness (b), and specific surface area) at each interval.Results showed that for this subject the type of matrix influenced the pathway that the peanut particles (embedded inside each matrix) were broken down. The d₅₀ of peanut particles within the bolus of the gelatine gel were greater than within the bolus of the chocolate throughout the chewing sequence until the point of swallowing. At the point of swallowing, the d₅₀ of peanut particles inside the bolus of the gelatine gel and chocolate were the same. The broadness value (b) and specific surface area of the peanut particles in the bolus of the chocolate were greater than those in the bolus of the gelatine gel throughout the chewing sequence. The matrices also induced different dynamic trends in the mass of bolus components during the chewing sequence.