A. D. Harris, R. A. Edden, K. Murphy, C. J. Evans, C. Y. Poon, N. Saxena, J. Hall, T. T. Liu, D. M. Bailey, and R. G. Wise Cardiff University Brain Research Imaging Centre (CUBRIC), Cardiff University, Cardiff, United Kingdom, Russell H Morgan Department of Radiology and Radiological Science, The Johns Hopkins University, Baltimore, Maryland, United States, Cardiff University Brain Imaging Rese...

Many of the applications of compressed sensing have been based on variable density sampling, where certain sections of the sampling coefficients are sampled more densely. Furthermore, it has been observed that these sampling schemes are dependent not only on sparsity but also on the sparsity structure of the underlying signal. This paper extends the result of (Adcock, Hansen, Poon and Roman, ar...

Intractable inference has been a major barrier to the wide adoption of statistical relational models. Existing exact methods suffer from a lack of scalability, and approximate methods tend to be unreliable. Sumproduct networks (SPNs; Poon and Domingos 2011) are a recently-proposed probabilistic architecture that guarantees tractable exact inference, even on many high-treewidth models. SPNs are ...

A strict orthogonal drawing of a graph G = (V,E) in R is a drawing of G such that each vertex is mapped to a distinct point and each edge is mapped to a horizontal or vertical line segment. A graph G is HV -restricted if each of its edges is assigned a horizontal or vertical orientation. A strict orthogonal drawing of an HV -restricted graph G is good if it is planar and respects the edge orien...

diatric Patients with Severe Acute Respiratory Syndrome and Correlation with Viral Load, Terence C.W. Poon, K.C. Allen Chan, Pak-Cheung Ng, Rossa W.K. Chiu, Irene L. Ang, Yu-kwan Tong, Enders K.O. Ng, Frankie W.T. Cheng, Albert M. Li, Ellis K.L. Hon, Tai-Fai Fok, and Y.M. Dennis Lo ( Centre for Emerging Infectious Diseases and Departments of 2 Clinical Oncology, 3 Chemical Pathology, and 4 Paed...

Let A and C be square complex matrices of size n, the C-determinantal range of A is the subset of the complex plane {det (A− UCU∗) : UU∗ = In}. If A,C are both Hermitian matrices, then by a result of M. Fiedler [11] this set is a real line segment. In this paper we study this set for the case when C is a Hermitian matrix. Our purpose is to revisit and improve two well-known results on this topi...

We conducted a global study of the long-term issuer ratings of nonfinancial firms from Standard and Poor's Ratings Services (S&P) for the period 1998–2003. Specifically, we focused on the solicited versus unsolicited ratings and sample-selection bias in the analysis. Unlike the literature, we adopted an improved method using Wooldridge’s instrumentalvariable approach to mitigate the concern of ...

About 2WT real numbers are needed to fully characterize a signal s(t) of effective duration T and bandwidth W ; we then say that the approximate dimension of the signal space is 2WT [1]. In a more general case, and in addition to time t, s(r, t) also depends on the position in space r. Such a model appears, for instance, in the electromagnetic analysis of waveguides or optical fibres [2]. The b...

Chie C. Poon Andrew C. Tam IBM Almaden Research Center 650 Harry Road San Jose, California 95120 Abstract. We investigate deformation of stainless steel and ceramic specimens with a precision of the order of tens of nanometers using a pulsed laser beam. Such a technique is useful, for example, in a process of removing distortions on magnetic head components to achieve a better contact between t...

Sumnary For any society or community, there is ample room for a prismatic view of its ~ome ~tnibution. Conventional measures of income (di¢~butionatl ~nequatitieh, such as the G~~ coe66~clent, may not depict a realistic picture accross the individual sectors of an income distributional spectrum. Stratification into poon, middle cea6~ and a66tuent sectors generally provides a better understandin...