Improved Techniques for Video Compression and Communication

Thesis (Ph.D.)--University of Washington, 2016-06

A comparison between capillary and imaging techniques for sizing bubbles in flotation systems

This communication reports a laboratory and plant comparison between the University of Cape Town (UCT) device (capillary) and the McGill University bubble sizing method (imaging). The laboratory work was conducted on single bubbles to establish the accuracy of the techniques by comparing with a reference method (capture in a burette). Single bubble measurements with the McGill University technique showed a tendency to slightly underestimate (4% for a 1.3 mm bubble) and the UCT technique to slightly overestimate (1% for the 1.3 man bubble). Both trends are anticipated from fundamental considerations. In the UCT technique bubble breakup was observed when measuring a 2.7 mm bubble using a 0.5 mm ID capillary tube. A discrepancy of 11% was determined when comparing the techniques in an industrial-scale mechanical flotation cell. The possible sources of bias are discussed. (C) 2003 Elsevier Ltd. All rights reserved.

Regulation of antigen processing and presentation molecules in West Nile virus-infected human skin fibroblasts

Infection of humans with the West Nile flavivirus principally occurs via tick and mosquito bites. Here, we document the expression of antigen processing and presentation molecules in West Nile virus (WNV)-infected human skin fibroblast (HFF) cells. Using a new Flavivirus-specific antibody, 4G4, we have analyzed cell surface human leukocyte antigen (HLA) expression on virus-infected cells at a single cell level. Using this approach, we show that West Nile Virus infection alters surface HLA expression on both infected HFF and neighboring uninfected HFF cells. Interestingly, increased surface HLA evident on infected HFF cultures is almost entirely due to virus-induced interferon (IFN)alpha/beta because IFNalpha/beta-neutralizing antibodies completely prevent increased surface HLA expression. In contrast, RT-PCR analysis indicates that WNV infection results in increased mRNAs for HLA-A, -B, and -C genes, and HLA-associated molecules low molecular weight polypeptide-2 (LMP-2) and transporter associated with antigen presentation-1 (TAP-1), but induction of these mRNAs is not diminished in HFF cells cultured with IFNalpha/beta-neutralizing antibodies. Taken together, these data support the idea that that both cytokine-dependent and cytokine-independent mechanisms account for WNV-induced HLA expression in human skin fibroblasts. (C) 2004 Elsevier Inc. All rights reserved.

Thermal stability analysis of organo-silicates, using solid phase microextraction techniques

An analysis of thermal degradation products evolved during the melt processing of organo-layered silicates (OLS) was carried out via the use of a solid phase microextraction (SPME) technique. Two commerical OLSs and one produced in-house were prepared for comparision. The solid phase microextraction technique proved to be a very effective technique for investigating the degradation of the OLS at a specific processing temperature. The results showed that most available OLSs will degrade under typical conditions required for the melt processing of many polymers, including thermoplastic polyurethanes. It is suggested that these degradation products may lead to changes in the structure and properties of the final polymer, particularly in thermoplastic polyurethanes, which seem significantly succeptable to the presence of these products. It is also suggested that many commercially available OLSs are produced in such a way that results in an excess of unbound organic modifier, giving rise to a greater quantity of degradation products. All OLSs where compared and characterised by TGA and GC-MS. (c) 2004 Elsevier B.V. All rights reserved.

Comparison of gas hold-up distribution measurement in a flotation cell using capturing and conductivity techniques

This paper presents and interprets results of experimental measurements of the spatial gas hold-up distribution in a 3 (3) glass rectangular flotation cell at the JKMRC using two different techniques. The gas hold-up device with the capturing technique was developed at the JKMRC and has been used widely in the P9 project(1) while the one with conductivity technique was developed at the CSIRO Thermal and Fluids Engineering laboratory at Highett, Victoria, Australia. Measurements were conducted at more than 64 locations in the cell to determine the local gas hold-up distribution in the cell. Since the measurements using the two techniques were conducted at the same locations, the results may be compared with each other. The results indicate that the gas hold-up varies widely inside the flotation cell. The gas hold-up distributions measured by the two techniques are relatively similar except in some locations which can be reasonably explained. (c) 2006 Elsevier Ltd. All rights reserved.

Approximate processing of massive continuous quantile queries over high-speed data streams

Quantile computation has many applications including data mining and financial data analysis. It has been shown that an is an element of-approximate summary can be maintained so that, given a quantile query d (phi, is an element of), the data item at rank [phi N] may be approximately obtained within the rank error precision is an element of N over all N data items in a data stream or in a sliding window. However, scalable online processing of massive continuous quantile queries with different phi and is an element of poses a new challenge because the summary is continuously updated with new arrivals of data items. In this paper, first we aim to dramatically reduce the number of distinct query results by grouping a set of different queries into a cluster so that they can be processed virtually as a single query while the precision requirements from users can be retained. Second, we aim to minimize the total query processing costs. Efficient algorithms are developed to minimize the total number of times for reprocessing clusters and to produce the minimum number of clusters, respectively. The techniques are extended to maintain near-optimal clustering when queries are registered and removed in an arbitrary fashion against whole data streams or sliding windows. In addition to theoretical analysis, our performance study indicates that the proposed techniques are indeed scalable with respect to the number of input queries as well as the number of items and the item arrival rate in a data stream.

Early and mid Holocene tool-use and processing of taro (Colocasia esculenta), yam (Dioscorea sp.) and other plants at Kuk Swamp in the highlands of Papua New Guinea

Recent multidisciplinary investigations document an independent emergence of agriculture at Kuk Swamp in the highlands of Papua New Guinea. In this paper we report preliminary usewear analysis and details of prehistoric use of stone tools for processing starchy food and other plants at Kuk Swamp. Morphological diagnostics for starch granules are reported for two potentially significant economic species, taro (Colocasia esculenta) and yam (Dioscorea sp.), following comparisons between prehistoric and botanical reference specimens. Usewear and residue analyses of starch granules indicate that both these species were processed on the wetland margin during the early and mid Holocene. We argue that processing of taro and yam commences by at least 10,200 calibrated years before present (cal BP), although the taro and yam starch granules do not permit us to distinguish between wild or cultivated forms. From at least 6950 to 6440 cal BP the processing of taro, yam and other plants indicates that they are likely to have been integrated into cultivation practices on the wetland edge.

The economics of inclusion body processing

Many recombinant proteins are often over-expressed in host cells, such as Escherichia coli, and are found as insoluble and inactive protein aggregates known as inclusion bodies (IBs). Recently, a novel process for IB extraction and solubilisation, based on chemical extraction, has been reported. While this method has the potential to radically intensify traditional IB processing, the process economics of the new technique have yet to be reported. This study focuses on the evaluation of process economics for several IB processing schemes based on chemical extraction and/or traditional techniques. Simulations and economic analysis were conducted at various processing conditions using granulocyte macrophage-colony stimulating factor, expressed as IBs in E. coli, as a model protein. In most cases, IB processing schemes based on chemical extraction having a shorter downstream cascade demonstrated a competitive economic edge over the conventional route, validating the new process as an economically more viable alternative for IB processing.

Semantic caching for multiresolution spatial query processing in mobile environments

Spatial data are particularly useful in mobile environments. However, due to the low bandwidth of most wireless networks, developing large spatial database applications becomes a challenging process. In this paper, we provide the first attempt to combine two important techniques, multiresolution spatial data structure and semantic caching, towards efficient spatial query processing in mobile environments. Based on the study of the characteristics of multiresolution spatial data (MSD) and multiresolution spatial query, we propose a new semantic caching model called Multiresolution Semantic Caching (MSC) for caching MSD in mobile environments. MSC enriches the traditional three-category query processing in semantic cache to five categories, thus improving the performance in three ways: 1) a reduction in the amount and complexity of the remainder queries; 2) the redundant transmission of spatial data already residing in a cache is avoided; 3) a provision for satisfactory answers before 100% query results have been transmitted to the client side. Our extensive experiments on a very large and complex real spatial database show that MSC outperforms the traditional semantic caching models significantly

Effectiveness of document representation for classification

Conventionally, document classification researches focus on improving the learning capabilities of classifiers. Nevertheless, according to our observation, the effectiveness of classification is limited by the suitability of document representation. Intuitively, the more features that are used in representation, the more comprehensive that documents are represented. However, if a representation contains too many irrelevant features, the classifier would suffer from not only the curse of high dimensionality, but also overfitting. To address this problem of suitableness of document representations, we present a classifier-independent approach to measure the effectiveness of document representations. Our approach utilises a labelled document corpus to estimate the distribution of documents in the feature space. By looking through documents in this way, we can clearly identify the contributions made by different features toward the document classification. Some experiments have been performed to show how the effectiveness is evaluated. Our approach can be used as a tool to assist feature selection, dimensionality reduction and document classification.

Concept-based document readability in domain specific information retrieval

Domain specific information retrieval has become in demand. Not only domain experts, but also average non-expert users are interested in searching domain specific (e.g., medical and health) information from online resources. However, a typical problem to average users is that the search results are always a mixture of documents with different levels of readability. Non-expert users may want to see documents with higher readability on the top of the list. Consequently the search results need to be re-ranked in a descending order of readability. It is often not practical for domain experts to manually label the readability of documents for large databases. Computational models of readability needs to be investigated. However, traditional readability formulas are designed for general purpose text and insufficient to deal with technical materials for domain specific information retrieval. More advanced algorithms such as textual coherence model are computationally expensive for re-ranking a large number of retrieved documents. In this paper, we propose an effective and computationally tractable concept-based model of text readability. In addition to textual genres of a document, our model also takes into account domain specific knowledge, i.e., how the domain-specific concepts contained in the document affect the document’s readability. Three major readability formulas are proposed and applied to health and medical information retrieval. Experimental results show that our proposed readability formulas lead to remarkable improvements in terms of correlation with users’ readability ratings over four traditional readability measures.