2,140 research outputs found

    Colour consistency in computer vision : a multiple image dynamic exposure colour classification system : a thesis presented to the Institute of Natural and Mathematical Sciences in fulfilment of the requirements for the degree of Master of Science in Computer Science at Massey University, Albany, Auckland, New Zealand

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    Colour classification vision systems face difficulty when a scene contains both very bright and dark regions. An indistinguishable colour at one exposure may be distinguishable at another. The use of multiple cameras with varying levels of sensitivity is explored in this thesis, aiding the classification of colours in scenes with high illumination ranges. Titled the Multiple Image Dynamic Exposure Colour Classification (MIDECC) System, pie-slice classifiers are optimised for normalised red/green and cyan/magenta colour spaces. The MIDECC system finds a limited section of hyperspace for each classifier, resulting in a process which requires minimal manual input with the ability to filter background samples without specialised training. In experimental implementation, automatic multiple-camera exposure, data sampling, training and colour space evaluation to recognise 8 target colours across 14 different lighting scenarios is processed in approximately 30 seconds. The system provides computationally effective training and classification, outputting an overall true positive score of 92.4% with an illumination range between bright and dim regions of 880 lux. False positive classifications are minimised to 4.24%, assisted by heuristic background filtering. The limited search space classifiers and layout of the colour spaces ensures the MIDECC system is less likely to classify dissimilar colours, requiring a certain ‘confidence’ level before a match is outputted. Unfortunately the system struggles to classify colours under extremely bright illumination due to the simplistic classification building technique. Results are compared to the common machine learning algorithms Naïve Bayes, Neural Networks, Random Tree and C4.5 Tree Classifiers. These algorithms return greater than 98.5% true positives and less than 1.53% false positives, with Random Tree and Naïve Bayes providing the best and worst comparable algorithms, respectively. Although resulting in a lower classification rate, the MIDECC system trains with minimal user input, ignores background and untrained samples when classifying and trains faster than most of the studied machine learning algorithms.Colour classification vision systems face difficulty when a scene contains both very bright and dark regions. An indistinguishable colour at one exposure may be distinguishable at another. The use of multiple cameras with varying levels of sensitivity is explored in this thesis, aiding the classification of colours in scenes with high illumination ranges. Titled the Multiple Image Dynamic Exposure Colour Classification (MIDECC) System, pie-slice classifiers are optimised for normalised red/green and cyan/magenta colour spaces. The MIDECC system finds a limited section of hyperspace for each classifier, resulting in a process which requires minimal manual input with the ability to filter background samples without specialised training. In experimental implementation, automatic multiple-camera exposure, data sampling, training and colour space evaluation to recognise 8 target colours across 14 different lighting scenarios is processed in approximately 30 seconds. The system provides computationally effective training and classification, outputting an overall true positive score of 92.4% with an illumination range between bright and dim regions of 880 lux. False positive classifications are minimised to 4.24%, assisted by heuristic background filtering. The limited search space classifiers and layout of the colour spaces ensures the MIDECC system is less likely to classify dissimilar colours, requiring a certain ‘confidence’ level before a match is outputted. Unfortunately the system struggles to classify colours under extremely bright illumination due to the simplistic classification building technique. Results are compared to the common machine learning algorithms Naïve Bayes, Neural Networks, Random Tree and C4.5 Tree Classifiers. These algorithms return greater than 98.5% true positives and less than 1.53% false positives, with Random Tree and Naïve Bayes providing the best and worst comparable algorithms, respectively. Although resulting in a lower classification rate, the MIDECC system trains with minimal user input, ignores background and untrained samples when classifying and trains faster than most of the studied machine learning algorithms

    Thin plate buckling mitigation and reduction challenges for naval ships

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    Thin plate buckling or distortion on ship structures is an ongoing issue for shipbuilders. It has been identified that a significant number of factors can be put in place based on prior knowledge and good practice. Additionally, research work aimed at reducing thin plate distortion has been relatively prolific, particularly in the area of simulation modelling. However, the uptake in the research findings by industry has been relatively low. A number of these findings are discussed and their application considered. For any further reductions in thin plate distortion to be generated there is a clear need for better interaction between the research institutes and the industry

    Functional specialization of the yeast Rho1 GTP exchange factors

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    Rho GTPases are regulated in complex spatiotemporal patterns that may be dependent, in part at least, on the multiplicity of their GTP exchange factors (GEFs). Here, we examine the extent of and basis for functional specialization of the Rom2 and Tus1 GEFs that activate the yeast Rho1 GTPase, the ortholog of mammalian RhoA. First, we find that these GEFs selectively activate different Rho1-effector branches. Second, the synthetic genetic networks around ROM2 and TUS1 confirm very different global in vivo roles for these GEFs. Third, the GEFs are not functionally interchangeable: Tus1 cannot replace the essential role of Rom2, even when overexpressed. Fourth, we find that Rom2 and Tus1 localize differently: Rom2 to the growing bud surface and to the bud neck at cytokinesis; Tus1 only to the bud neck but in a distinct pattern. Finally, we find that these GEFs are dependent on different protein co-factors: Rom2 function and localization is largely dependent on Ack1, a SEL1 domain containing protein; Tus1 function and localization is largely dependent on the Tus1-interacting protein Ypl066w (which we name Rgl1). We have revealed a surprising level of diversity among the Rho1 GEFs that contributes another level of complexity to the spatiotemporal control of Rho1

    Der Streit um Christa Wolf : eine Untersuchung ihrer Rolle als Geheimer Informator der Stasi, als Mittelpunkt des Literaturstreits und als Autorin des Romans, Der geteilte Himmel : a thesis presented in partial fulfilment of the requirements for the degree of Master of Arts in German at Massey University

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    1990 saw the beginning of the 'Literaturstreit' (the Literary Controversy) in East and West Germany. The 'Literaturstreit' was sparked off by the publication of Christa Wolf's short narrative Was bleibt in June 1990. Wolf's insistence that the narrative had been written back in 1979, when she was under Stasi surveillance, and that she had revised it in 1989 prior to publication, brought a barrage of criticism from prominent critics from all over the world. The 'Literaturstreit' was further fired by the publication of the Stasi files in 1993, which revealed Christa Wolf's involvement with the Stasi. In the first part of this thesis the Stasi files are investigated in order to determine the nature of the information given to the Stasi by Christa Wolf and to establish her actual involvement with them. In order to establish a picture of her character at the time in which she was recruited by the Stasi, the first chapter examines two curricula vitae written by herself and letters, reports and assessments regarding Christa Wolf written by colleagues and Stasi agents. The second chapter takes a close look at the actual process used by the Stasi to recruit Wolf as a "Secret Informer". It is my intention in the second part of this thesis to compare the picture of Christa Wolf seen in the Stasi files with the picture of her established in her narrative Der geteilte Himmel and with the picture of her which emerges through the criticisms levelled at her during the 'Literaturstreit'. Chapter Three outlines the major issues of the 'Literaturstreit' and events leading to it and summarizes the main critical arguments against Christa Wolf during this time. The focus of chapter Four is an examination of Christa Wolf's novel Der geteilte Himmel. published in 1963. The reason behind the choice of this novel is that it is the literary work which was published shortly after Christa Wolfs involvement with the Stasi and was presumably written - at least in part - while she was still officially in their employ. It is concluded that Christa Wolf is not the naive or self-consumed person portrayed in the Stasi files who is afraid to express her beliefs and make judgements. She appears to have felt obliged to work for the Stasi due to the position that she held at the time, but she may also have seen it as an opportunity for her to gain insight into the real situation in the party and in its institutions. The comparison between the Christa Wolf as portrayed in the Stasi files, the Christa Wolf as seen by the critics in the 'Literaturstreit' and the Christa Wolf who expresses herself through the literary text is revealing. However, despite the differences - legitimate or otherwise - that emerge, her faith in the real values of true Socialism remains constant

    Control of actin turnover by a salmonella invasion protein.

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    Salmonella force their way into nonphagocytic host intestinal cells to initiate infection. Uptake is triggered by delivery into the target cell of bacterial effector proteins that stimulate cytoskeletal rearrangements and membrane ruffling. The Salmonella invasion protein A (SipA) effector is an actin binding protein that enhances uptake efficiency by promoting actin polymerization. SipA-bound actin filaments (F-actin) are also resistant to artificial disassembly in vitro. Using biochemical assays of actin dynamics and actin-based motility models, we demonstrate that SipA directly arrests cellular mechanisms of actin turnover. SipA inhibits ADF/cofilin-directed depolymerization both by preventing binding of ADF and cofilin and by displacing them from F-actin. SipA also protects F-actin from gelsolin-directed severing and reanneals gelsolin-severed F-actin fragments. These data suggest that SipA focuses host cytoskeletal reorganization by locally inhibiting both ADF/cofilin- and gelsolin-directed actin disassembly, while simultaneously stimulating pathogen-induced actin polymerization

    Crystallization and preliminary X-ray diffraction studies of the oxygenating subunit of 3,6-diketocamphane monooxygenase from Pseudomonas putida.

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    Journal ArticleResearch Support, Non-U.S. Gov'tThe oxygenating constituent of the 3,6-diketocamphane monooxygenase isozyme from Pseudomonas putida NCIMB 10007 has been crystallized under two different conditions. Crystals were initially grown from polyethylene glycol (PEG) 8000 and sodium acetate using the vapour-phase diffusion method. The crystals were of orthorhombic P212121 space group, with cell dimensions a = 55.8, b = 94.5 and c = 163.7 A and diffracted to 2.8 A resolution. More recently, improved crystals, which diffracted beyond 2 A, have been grown from ammonium sulfate. These crystals also belong to the orthorhombic P212121 space group, with cell dimensions of a = 54.6, b = 93.2 and c = 154. 1 A. A full native data set to 2.5 A resolution has been collected from the ammonium sulfate grown crystals.BBSR

    Deciphering interplay between Salmonella invasion effectors

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    Bacterial pathogens have evolved a specialized type III secretion system (T3SS) to translocate virulence effector proteins directly into eukaryotic target cells. Salmonellae deploy effectors that trigger localized actin reorganization to force their own entry into non-phagocytic host cells. Six effectors (SipC, SipA, SopE/2, SopB, SptP) can individually manipulate actin dynamics at the plasma membrane, which acts as a ‘signaling hub’ during Salmonella invasion. The extent of crosstalk between these spatially coincident effectors remains unknown. Here we describe trans and cis binary entry effector interplay (BENEFIT) screens that systematically examine functional associations between effectors following their delivery into the host cell. The results reveal extensive ordered synergistic and antagonistic relationships and their relative potency, and illuminate an unexpectedly sophisticated signaling network evolved through longstanding pathogen–host interaction

    The pharmacokinetics of anthocyanins and their metabolites in humans

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    Background and Purpose: Anthocyanins are phytochemicals with reported vasoactive bioactivity. However, given their instability at neutral pH, they are presumed to undergo significant degradation and subsequent biotransformation. The aim of the present study was to establish the pharmacokinetics of the metabolites of cyanidin-3-glucoside (C3G), a widely consumed dietary phytochemical with potential cardioprotective properties. Experimental Approach: A 500 mg oral bolus dose of 6,8,10,3′,5′-13C5-C3G was fed to eight healthy male participants, followed by a 48 h collection (0, 0.5, 1, 2, 4, 6, 24, 48 h) of blood, urine and faecal samples. Samples were analysed by HPLC-ESI-MS/MS with elimination kinetics established using non-compartmental pharmacokinetic modelling. Key Results: Seventeen 13C-labelled compounds were identified in the serum, including 13C5-C3G, its degradation products, protocatechuic acid (PCA) and phloroglucinaldehyde (PGA), 13 metabolites of PCA and 1 metabolite derived from PGA. The maximal concentrations of the phenolic metabolites (Cmax) ranged from 10 to 2000 nM, between 2 and 30 h (tmax) post-consumption, with half-lives of elimination observed between 0.5 and 96 h. The major phenolic metabolites identified were hippuric acid and ferulic acid, which peaked in the serum at approximately 16 and 8 h respectively. Conclusions and Implications: Anthocyanins are metabolized to a structurally diverse range of metabolites that exhibit dynamic kinetic profiles. Understanding the elimination kinetics of these metabolites is key to the design of future studies examining their utility in dietary interventions or as therapeutics for disease risk reduction

    Echocardiographic chamber quantification in a healthy Dutch population

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    Aim For accurate interpretation of echocardiographic measurements normative data are required, which are provided by guidelines. For this article, the hypothesis was that these cannot be extrapolated to the Dutch population, since in Dutch clinical practice often higher values are found, which may not be pathological but physiological. Therefore this study aimed to 1) obtain and propose normative values for cardiac chamber quantification in a healthy Dutch population and 2) determine influences of baseline characteristics on these measurements. Methods Prospectively recruited healthy subjects, aged 20–72 years (at least 28 subjects per age decade, equally distributed for gender) underwent physical examination and 2D and 3D echocardiography. Both ventricles and atria were assessed and volumes were calculated. Results 147 subjects were included (age 44 ± 14 years, 50% female). Overall, feasibility was good for both linear and volumetric measurements. Linear and volumetric parameters were consistently higher than current guidelines recommend, while functional parameters were in line with the guidelines. This was more so in the older population. 3D volumes were higher than 2D volumes. Gender dependency was seen in all body surface area (BSA) corrected volumes and with increasing age, ejection fractions decreased. Conclusion This study provides 2D and 3D echocardiographic reference ranges for both ventricles and atria de-rived from a healthy Dutch population. BSA indexed volumes are gender-dependent, age did not influence ventricular volumes and a rise in blood pressure was independently associated with increased right ventricular volumes. The higher volumes found may be indicative for the Dutch population being the tallest in the world
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