Digital filter design using root moments for sum-of-all-pass structures from complete and partial specifications

Published versio

An algebraic approach to the estimation of the order of FIR filters from complete and partial magnitude and phase specifications

Published versio

iIRSL dating of K-feldspar and its application to Fajiagouwan, Salawusu site in Central China

Dating Protocols Improvements: abstract no. P19published_or_final_versio

Latent Topic Text Representation Learning on Statistical Manifolds

The explosive growth of text data requires effective methods to represent and classify these texts. Many text learning methods have been proposed, like statistics-based methods, semantic similarity methods, and deep learning methods. The statistics-based methods focus on comparing the substructure of text, which ignores the semantic similarity between different words. Semantic similarity methods learn a text representation by training word embedding and representing text as the average vector of all words. However, these methods cannot capture the topic diversity of words and texts clearly. Recently, deep learning methods such as CNNs and RNNs have been studied. However, the vanishing gradient problem and time complexity for parameter selection limit their applications. In this paper, we propose a novel and efficient text learning framework, named Latent Topic Text Representation Learning. Our method aims to provide an effective text representation and text measurement with latent topics. With the assumption that words on the same topic follow a Gaussian distribution, texts are represented as a mixture of topics, i.e., a Gaussian mixture model. Our framework is able to effectively measure text distance to perform text categorization tasks by leveraging statistical manifolds. Experimental results on text representation and classification, and topic coherence demonstrate the effectiveness of the proposed method

Reasoning about topological and cardinal direction relations between 2-dimensional spatial objects

Increasing the expressiveness of qualitative spatial calculi is an essential step towards meeting the requirements of applications. This can be achieved by combining existing calculi in a way that we can express spatial information using relations from multiple calculi. The great challenge is to develop reasoning algorithms that are correct and complete when reasoning over the combined information. Previous work has mainly studied cases where the interaction between the combined calculi was small, or where one of the two calculi was very simple. In this paper we tackle the important combination of topological and directional information for extended spatial objects. We combine some of the best known calculi in qualitative spatial reasoning, the RCC8 algebra for representing topological information, and the Rectangle Algebra (RA) and the Cardinal Direction Calculus (CDC) for directional information. We consider two different interpretations of the RCC8 algebra, one uses a weak connectedness relation, the other uses a strong connectedness relation. In both interpretations, we show that reasoning with topological and directional information is decidable and remains in NP. Our computational complexity results unveil the significant differences between RA and CDC, and that between weak and strong RCC8 models. Take the combination of basic RCC8 and basic CDC constraints as an example: we show that the consistency problem is in P only when we use the strong RCC8 algebra and explicitly know the corresponding basic RA constraints

A chronological framework for colluviation during the last 110 kyr in KwaZulu/Natal

Luminescence dating techniques have been applied to colluvial sediments of the Masotcheni Formation. The ages obtained suggest that colluvial deposition occurred during late Oxygen Isotope Stage 5, after the peak of the Last Interglacial (Sub-stage 5e). Further colluvial deposition seems to have commenced early in Stage 3, following a period of donga erosion. A soil was then formed during Stage 3 in the top of this deposit at two of the sites, and this was covered by more colluvial deposits before Stage 3 ended. Evidence for late Holocene colluviation is also presented. -from Authorspublished_or_final_versio

Indoor Positioning Techniques Based on Wireless LAN

As well as delivering high speed internet, Wireless LAN (WLAN) can be used as an effective indoor positioning system. It is competitive in terms of both accuracy and cost compared to similar systems. To date, several signal strength based techniques have been proposed. Researchers at the University of New South Wales (UNSW) have developed several innovative implementations of WLAN positioning systems. This paper describes the techniques used and details the experimental results of the research

Late-onset bloodstream infection and perturbed maturation of the gastrointestinal microbiota in premature infants

Late-onset bloodstream infection (LO-BSI) is a common complication of prematurity, and lack of timely diagnosis and treatment can have life-threatening consequences. We sought to identify clinical characteristics and microbial signatures in the gastrointestinal microbiota preceding diagnosis of LO-BSI in premature infants.Daily faecal samples and clinical data were collected over two years from 369 premature neonates (<32 weeks gestation). We analysed samples from 22 neonates who developed LO-BSI and 44 matched control infants. Next-generation sequencing of 16S rRNA gene regions amplified by PCR from total faecal DNA was used to characterise the microbiota of faecal samples preceding diagnosis from infants with LO-BSI and controls. Culture of selected samples was undertaken, and bacterial isolates identified using MALDI-TOF. Antibiograms from bloodstream and faecal isolates were compared to explore strain similarity.From the week prior to diagnosis, infants with LO-BSI had higher proportions of faecal aerobes/facultative anaerobes compared to controls. Risk factors for LO-BSI were identified by multivariate analysis. Enterobacteriaceal sepsis was associated with antecedent multiple lines, low birth weight and a faecal microbiota with prominent Enterobacteriaceae. Staphylococcal sepsis was associated with Staphylococcus OTU faecal over-abundance, and the number of days prior to diagnosis of mechanical ventilation and of the presence of centrally-placed lines. In 12 cases, the antibiogram of the bloodstream isolate matched that of a component of the faecal microbiota in the sample collected closest to diagnosis.The gastrointestinal tract is an important reservoir for LO-BSI organisms, pathogens translocating across the epithelial barrier. LO-BSI is associated with an aberrant microbiota, with abundant staphylococci and Enterobacteriaceae and a failure to mature towards predominance of obligate anaerobes

SEARCHING FOR DEBRIS DISKS AROUND SEVEN RADIO PULSARS

We report on our searches for debris disks around seven relatively nearby radio pulsars, which are isolated sources that were carefully selected as targets on the basis of our deep Ks-band imaging survey. The Ks images obtained with the 6.5m Baade Magellan Telescope at Las Campanas Observatory are analyzed together with the Spitzer/IRAC images at 4.5 and 8.0μm and the WISE images at 3.4, 4.6, 12, and 22μm. No infrared counterparts of these pulsars are found, with flux upper limits of ∼μJy at near-infrared (λ < 10μm) and ∼10–1000μJy at mid-infrared wavelengths (λ > 10 μm). The results of this search are discussed in terms of the efficiency of converting the pulsar spin-down energy to thermal energy and X-ray heating of debris disks, with a comparison made of the two magnetars 4U 0142+61 and 1E 2259+586, which are suggested to harbor a debris disk.published_or_final_versio