17,967 research outputs found

    Reducing Spatial Data Complexity for Classification Models

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    Intelligent data analytics gradually becomes a day-to-day reality of today's businesses. However, despite rapidly increasing storage and computational power current state-of-the-art predictive models still can not handle massive and noisy corporate data warehouses. What is more adaptive and real-time operational environment requires multiple models to be frequently retrained which fiirther hinders their use. Various data reduction techniques ranging from data sampling up to density retention models attempt to address this challenge by capturing a summarised data structure, yet they either do not account for labelled data or degrade the classification performance of the model trained on the condensed dataset. Our response is a proposition of a new general framework for reducing the complexity of labelled data by means of controlled spatial redistribution of class densities in the input space. On the example of Parzen Labelled Data Compressor (PLDC) we demonstrate a simulatory data condensation process directly inspired by the electrostatic field interaction where the data are moved and merged following the attracting and repelling interactions with the other labelled data. The process is controlled by the class density function built on the original data that acts as a class-sensitive potential field ensuring preservation of the original class density distributions, yet allowing data to rearrange and merge joining together their soft class partitions. As a result we achieved a model that reduces the labelled datasets much further than any competitive approaches yet with the maximum retention of the original class densities and hence the classification performance. PLDC leaves the reduced dataset with the soft accumulative class weights allowing for efficient online updates and as shown in a series of experiments if coupled with Parzen Density Classifier (PDC) significantly outperforms competitive data condensation methods in terms of classification performance at the comparable compression levels

    Stasis-theory in Homeric commentary

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    (i) Analysis of the small number of references to the rhetorical theory of stasis (issue-theory) in the Homeric scholia shows that they assume a modified version of the theory of Athenaeus, a contemporary and rival of Hermagoras of Temnos. (ii) In his discussion of Agamemnon's speech in Iliad 3.456-60 Eustathius follows the discussion in Plutarch Quaestiones convivales 9.13, rather than that in the scholia. It is shown that this is justified on technical grounds. The interpretation in the scholia does not fit Agamemnon's speech, and must have originated in a discussion of the attested Homeric 'problem' concerning claims that the Trojans had broken their oath

    Multiparameter vision testing apparatus

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    Compact vision testing apparatus is described for testing a large number of physiological characteristics of the eyes and visual system of a human subject. The head of the subject is inserted into a viewing port at one end of a light-tight housing containing various optical assemblies. Visual acuity and other refractive characteristics and ocular muscle balance characteristics of the eyes of the subject are tested by means of a retractable phoroptor assembly carried near the viewing port and a film cassette unit carried in the rearward portion of the housing (the latter selectively providing a variety of different visual targets which are viewed through the optical system of the phoroptor assembly). The visual dark adaptation characteristics and absolute brightness threshold of the subject are tested by means of a projector assembly which selectively projects one or both of a variable intensity fixation target and a variable intensity adaptation test field onto a viewing screen located near the top of the housing

    Postmortem iris recognition and its application in human identification

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    Iris recognition is a validated and non-invasive human identification technology currently implemented for the purposes of surveillance and security (i.e. border control, schools, military). Similar to deoxyribonucleic acid (DNA), irises are a highly individualizing component of the human body. Based on a lack of genetic penetrance, irises are unique between an individual’s left and right iris and between identical twins, proving to be more individualizing than DNA. At this time, little to no research has been conducted on the use of postmortem iris scanning as a biometric measurement of identification. The purpose of this pilot study is to explore the use of iris recognition as a tool for postmortem identification. Objectives of the study include determining whether current iris recognition technology can locate and detect iris codes in postmortem globes, and if iris scans collected at different postmortem time intervals can be identified as the same iris initially enrolled. Data from 43 decedents involving 148 subsequent iris scans demonstrated a subsequent match rate of approximately 80%, supporting the theory that iris recognition technology is capable of detecting and identifying an individual’s iris code in a postmortem setting. A chi-square test of independence showed no significant difference between match outcomes and the globe scanned (left vs. right), and gender had no bearing on the match outcome. There was a significant relationship between iris color and match outcome, with blue/gray eyes yielding a lower match rate (59%) compared to brown (82%) or green/hazel eyes (88%), however, the sample size of blue/gray eyes in this study was not large enough to draw a meaningful conclusion. An isolated case involving an antemortem initial scan collected from an individual on life support yielded an accurate identification (match) with a subsequent scan captured at approximately 10 hours postmortem. Falsely rejected subsequent iris scans or "no match" results occurred in about 20% of scans; they were observed at each PMI range and varied from 19-30%. The false reject rate is too high to reliably establish non-identity when used alone and ideally would be significantly lower prior to implementation in a forensic setting; however, a "no match" could be confirmed using another method. Importantly, the data showed a false match rate or false accept rate (FAR) of zero, a result consistent with previous iris recognition studies in living individuals. The preliminary results of this pilot study demonstrate a plausible role for iris recognition in postmortem human identification. Implementation of a universal iris recognition database would benefit the medicolegal death investigation and forensic pathology communities, and has potential applications to other situations such as missing persons and human trafficking cases

    Biometric Security for Cell Phones

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    Cell phones are already prime targets for theft. The increasing functionality of cell phones is making them even more attractive. With the increase of cell phone functionality including personal digital assistance, banking, e-commerce, remote work, internet access and entertainment, more and more confidential data is stored on these devices. What is protecting this confidential data stored on cell phones? Studies have shown that even though most of the cell phone users are aware of the PIN security feature more than 50% of them are not using it either because of the lack of confidence in it or because of the inconvenience. A large majority of those users believes that an alternative approach to security would be a good idea.biometrics, security, fingerprint, face recognition, cell phones

    Angle stability and outflow in dual blade ab interno trabeculectomy with active versus passive chamber management.

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    PurposeTo compare intraoperative angle stability and postoperative outflow of two ab interno trabeculectomy devices that excise the trabecular meshwork with or without active aspiration and irrigation. We hypothesized that anterior segment optical coherence tomography (AS-OCT) allows for a quantitative comparison of intraoperative angle stability in a microincisional glaucoma surgery (MIGS) pig eye training model.MethodsTwelve freshly enucleated porcine eyes were measured with AS-OCT at baseline, at the beginning of the procedure and at its conclusion to determine the anterior chamber depth (ACD) and the nasal angle α in degrees. The right and left eye of pairs were randomly assigned to an active dual blade goniectome (aDBG) and a passive dual blade goniectome (pDBG) group, respectively. The aDBG had irrigation and aspiration ports while the pDBG required surgery under viscoelastic. We performed the procedures using our MIGS training system with a standard, motorized ophthalmic operating microscope. We estimated outflow by obtaining canalograms with fluorescent spheres.ResultsIn aDBG, the nasal angle remained wide open during the procedure at above 90° and did not change towards the end (100±10%, p = 0.9). In contrast, in pDBG, ACD decreased by 51±19% to 21% below baseline (p<0.01) while the angle progressively narrowed by 40±12% (p<0.001). Canalograms showed a similar extent of access to the outflow tract with the aDBG and the pDBG (p = 0.513). The average increase for the aDBG in the superonasal and inferonasal quadrants was between 27 to 31% and for the pDBG between 15 to 18%.ConclusionAS-OCT demonstrated that active irrigation and aspiration improved anterior chamber maintenance and ease of handling with the aDBG in this MIGS training model. The immediate postoperative outflow was equally good with both devices

    Automated knowledge capture in 2D and 3D design environments

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    In Life Cycle Engineering, it is vital that the engineering knowledge for the product is captured throughout its life cycle in a formal and structured manner. This will allow the information to be referred to in the future by engineers who did not work on the original design but are wanting to understand the reasons that certain design decisions were made. In the past, attempts were made to try to capture this knowledge by having the engineer record the knowledge manually during a design session. However, this is not only time-consuming but is also disruptive to the creative process. Therefore, the research presented in this paper is concerned with capturing design knowledge automatically using a traditional 2D design environment and also an immersive 3D design environment. The design knowledge is captured by continuously and non-intrusively logging the user during a design session and then storing this output in a structured eXtensible Markup Language (XML) format. Next, the XML data is analysed and the design processes that are involved can be visualised by the automatic generation of IDEF0 diagrams. Using this captured knowledge, it forms the basis of an interactive online assistance system to aid future users who are carrying out a similar design task

    Utilizing Microelectromechanical Systems (MEMS) Micro-Shutter Designs for Adaptive Coded Aperture Imaging (ACAI) Technologies

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    The Air Force has long relied on surveillance for intelligence and strategic purposes. Most surveillance systems rely on a lensing system to acquire their images, most of which are in either the visible or infrared wavelengths. Because lensing systems can be expensive, obtrusive, or hard to maintain, researchers have designed adaptive coded aperture imaging (ACAI) as a replacement system. Coded aperture imaging (CAI) has been used in both the astronomical and medical communities for years due to its ability to image light at short wavelengths and thus replacing conventional lenses. Where CAI is limited, researchers have discovered that adaptive coded aperture imaging can recover what is lost. ACAI uses a reconfigurable coding mask and digital signal processing to recover the original scene from the detector. In this effort, a prototype of MEMS microshutters has been designed and fabricated onto a 3 mm x 3 mm square of silicon substrate using the PolyMUMPS™ process. This prototype is a line-drivable array using thin flaps of polysilicon to cover and uncover an 8 x 8 array of 20 µm apertures and is the first known microshutter array to incorporate a line-drivable array driven by physical actuation. A characterization of the micro-shutters to include mechanical, electrical and optical properties is provided. This prototype, its actuation scheme, and other designs for individual microshutters have been modeled and studied for feasibility purposes, and this revealed that the actuation scheme failed in its design due to oversights in the design process and lack of space for each gear actuator. Because of conformality in the PolyMUMPS™ process, none of the microshutters could physically move, but optical analysis with a 632 nm HeNe laser revealed that they will not undergo upward deflection when exposed to irradiance sources of less than 0.5 W. The microshutters were also designed to transmit less than 20% of irradiated light and initial testing confirmed that fact. In addition, microshutters fabricated from an Al-Au alloy on a quartz wafer were characterized and showed that wedge-style shutters are functional, if not ideal for an ACAI array

    The Economic Theory of Production Conceals Opportunities for Sustainability Improvement

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    In analyses of action options regarding sustainability, the economic theory of production is often used as a conceptual starting point. We contend that this theory is deficient, even counterproductive. Especially, we argue that effective options exist for sustainability improvement that are not visible in this theory, and thus will not be taken into consideration when comparing alternative options based on it. We argue that the fundamental problem of the economic theory of production is that it cannot explain the formation of either cost or value in an adequate way. This situation seems to have been caused by the foci and assumptions of the “marginalist turn” of economics, starting from 1870, especially the denial to consider any internal organization of production other than that caused by prices and costs, the assumption of optimal efficiency, and the assumption of ends as given. The shortcomings of the economic theory of production are demonstrated through a case study on plasterboard (also known as drywall) installation. We show how practices for installation of these products, as advocated in lean construction, would not have been suggested or visible in a “sustainability” analysis based on economic theory
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