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1.
Despite the fact that progress in face recognition algorithms over the last decades has been made, changing lighting conditions and different face orientation still remain as a challenging problem. A standard face recognition system identifies the person by comparing the input picture against pictures of all faces in a database and finding the best match. Usually face matching is carried out in two steps: during the first step detection of a face is done by finding exact position of it in a complex background (various lightning condition), and in the second step face identification is performed using gathered databases. In reality detected faces can appear in different position and they can be rotated, so these disturbances reduce quality of the recognition algorithms dramatically. In this paper to increase the identification accuracy we propose original geometric normalization of the face, based on extracted facial feature position such as eyes. For the eyes localization lbllowing methods has been used: color based method, mean eye template and SVM (Support Vector Machine) technique. Experimental investigation has shown that the best results for eye center detection can be achieved using SVM technique. The recognition rate increases statistically by 28% using face orientation normalization based on the eyes position. 相似文献
2.
Kopustinskas A Adaskevicius R Krusinskas A Kopustinskiene DM Liobikas J Toleikis A 《Computer methods and programs in biomedicine》2006,82(3):231-237
We have developed an easy-to-use computer-based system for recording, displaying, storing and analyzing signals generated by Clark-type oxygen electrodes. A user-friendly interface of Windows-based program BioMed significantly increases the productivity of investigations. It allows to process, control, present and archive the experimental data in real time. A 12-bit analog-to-digital-converter, analog and digital filters, a possibility to zoom the obtained respiratory curves and calculation of the respiration rates by a linear regression method increase the resolution of the estimated oxygen consumption rates. The new system enables to register even small changes, such as 3-5 ngatoms O/min, in respiration rates of biological objects -- enzymes, mitochondria and permeabilized muscle fibers. The system has been developed and is regularly used for the respirometric investigations at the Laboratory of Biochemistry, Institute for Biomedical Research, Kaunas University of Medicine. 相似文献
3.
Rimvydas Rukšėnas Paul Curzon Ann Blandford 《Innovations in Systems and Software Engineering》2008,4(2):143-160
In this paper we are concerned with security issues that arise in the interaction between user and system. We focus on cognitive
processes that affect security of information flow from the user to the computer system and the resilience of the whole system
to intruder attacks. For this, we extend our framework developed for the verification of usability properties by introducing
two kinds of intruder models, an observer and an active intruder, with the associated security properties. Finally, we consider
small examples to illustrate the ideas and approach. These examples demonstrate how our framework can be used (a) to detect
confidentiality leaks, caused by a combination of an inappropriate design and certain aspects of human cognition, and (b)
to identify designs more susceptible to cognitively based intruder attacks. 相似文献
4.
Matthias Diethelm Andreas Schiller Maciej Kawecki Andrius Deviis Balthasar Blülle Sandra Jenatsch Evelyne Knapp Quirin Grossmann Beat Ruhstaller Frank Nüesch Roland Hany 《Advanced functional materials》2020,30(33)
In light‐emitting electrochemical cells (LECs), the position of the emission zone (EZ) is not predefined via a multilayer architecture design, but governed by a complex motion of electrical and ionic charges. As a result of the evolution of doped charge transport layers that enclose a dynamic intrinsic region until steady state is reached, the EZ is often dynamic during turn‐on. For thick sandwich polymer LECs, a continuous change of the emission color provides a direct visual indication of a moving EZ. Results from an optical and electrical analysis indicate that the intrinsic zone is narrow at early times, but starts to widen during operation, notably well before the electrical device optimum is reached. Results from numerical simulations demonstrate that the only precondition for this event to occur is that the mobilities of anions (μa) and cations (μc) are not equal, and the direction of the EZ shift dictates μc > μa. Quantitative ion profiles reveal that the displacement of ions stops when the intrinsic zone stabilizes, confirming the relation between ion movement and EZ shift. Finally, simulations indicate that the experimental current peak for constant‐voltage operation is intrinsic and the subsequent decay does not result from degradation, as commonly stated. 相似文献
5.
Mantas Ziaunys Andrius Sakalauskas Kamile Mikalauskaite Vytautas Smirnovas 《International journal of molecular sciences》2021,22(22)
Protein aggregate formation is linked with multiple amyloidoses, including Alzheimer‘s and Parkinson‘s diseases. Currently, the understanding of such fibrillar structure formation and propagation is still not sufficient, the outcome of which is a lack of potent, anti-amyloid drugs. The environmental conditions used during in vitro protein aggregation assays play an important role in determining both the aggregation kinetic parameters, as well as resulting fibril structure. In the case of alpha-synuclein, ionic strength has been shown as a crucial factor in its amyloid aggregation. In this work, we examine a large sample size of alpha-synuclein aggregation reactions under thirty different ionic strength and protein concentration combinations and determine the resulting fibril structural variations using their dye-binding properties, secondary structure and morphology. We show that both ionic strength and protein concentration determine the structural variability of alpha-synuclein amyloid fibrils and that sometimes even identical conditions can result in up to four distinct types of aggregates. 相似文献
6.
Process models are used to formulate knowledge about process behaviour. They are applied, e.g., to predict the process' future behaviour and for state estimation when reliable on-line measuring techniques to monitor the key variables of the process are not available. There are different sources of information available for modelling, which provide process knowledge in different representations. Some elements or aspects may be described by physically based mathematical models and others by heuristically obtained rules of thumb, while some information may still be hidden in the process data recorded during previous runs of the process. Heuristic rules are conveniently processed with fuzzy expert systems, while artificial neural networks present themselves as a powerful tool for uncovering the information within the process data without the need to transform the information into one of the other representations. Artificial neural networks and fuzzy technology are increasingly being employed for modelling biotechnological processes, thus extending the traditional way of process modelling by mathematical equations. However, a sufficiently comprehensive combination of all these techniques has not yet been put forward. Here, we present a simple way of combining all the available knowledge relating to a given process. In a case study, we demonstrate the development of a hybrid model for state estimation and prediction on the example of a yeast production process. The model was validated during a cultivation performed in a standard pilot-scale fermenter. 相似文献
7.
Design of a stable adaptive controller for driving aerobic fermentation processes near maximum oxygen transfer capacity 总被引:3,自引:2,他引:1
In many industrial fermentation processes oxygen availability is the main limiting factor for product production. Typically the dissolved oxygen (DO) concentration decreases continuously at the beginning of the batch until it reaches a critical level where the oxygen transfer rate is very close to the vessel's maximum transfer capacity. The process may be further driven close to this sensitive operating point with a controller that manipulates the carbon source feed rate. This operating strategy is linked with important productivity issues and is still frequently realised in open-loop at production scale. The main purpose of the present study is to derive an effective closed-loop control solution and to demonstrate its economical advantage in relation to the open-loop form of operation. A stable model reference adaptive controller (MRAC) was designed based on a phenomenological model of the process. The implementation requires two on-line measurements: the DO tension and oxygen transfer rate (OTR) between gas–liquid phases, which are nowadays standard and easily available in production facilities. The controller performance is accessed with a simulation case study. The main results show that the adaptive controller is precise, stable and robust to disturbances and to inaccuracies like variability in raw materials typical in fermentations run in complex media. The controller is simple, easy to implement, and could possibly improve productivity in processes for which oxygen transfer capacity is limiting growth and product production. 相似文献
8.
Azhar Fakharuddin Weiming Qiu Guillaume Croes Andrius Deviis Rokas Gegevi
ius Alexander Vakhnin Cedric Rolin Jan Genoe Robert Gehlhaar Andrey Kadashchuk Vidmantas Gulbinas Paul Heremans 《Advanced functional materials》2019,29(37)
Perovskite light emitting diodes (PeLEDs) have reached external quantum efficiencies (EQEs) over 21%. Their EQE, however, drops at increasing current densities (J) and their lifetime is still limited to just a few hours. The mechanisms leading to EQE roll‐off and device instability require thorough investigation. Here, improvement in EQE, EQE roll‐off, and lifetime of PeLEDs is demonstrated by tuning the balance of electron/hole transport into a mixed 2D/3D perovskite emissive layer. The mixed 2D/3D perovskite layer induces exciton confinement and beneficially influences the electron/hole distribution inside the perovskite layer. By tuning the electron injection to match the hole injection in such active layer, a nearly flat EQE for J = 0.1–200 mA cm?2, a reduced EQE roll‐off until J = 250 mA cm?2, and a half‐lifetime of ≈47 h at J = 10 mA cm?2 is reached. A model is also proposed to explain these improvements that account for the spatial electron/hole distributions. 相似文献
9.
Danutė Vaičiukynienė Ruben Paul Borg Andrius Kielė Aras Kantautas 《Ceramics International》2018,44(11):12573-12579
Recently, alkali-activated materials have shown great potential for use in the construction industry. The aim of this research was to study the properties of alkali-activated clay and the effect of incorporating AlF3 production waste from a fertilizer production plant. The AlF3 production waste, which was rich in alumina and silica, contributed to improved mechanical behaviour for all the mixtures investigated. This demonstrated the potential for use of this waste material. It was also noted that the dosage of Na2O, Al2O3, and SiO2 are significant factors that influence the binding mechanism and properties of alkali-activated clay samples. The raw materials, precursors, and alkali-activated samples were investigated by X-ray diffraction, fluorescence spectroscopy, and scanning electron microscopy. The highest compressive strength (17.50?MPa) was observed for alkali-activated clay samples containing 25% AlF3 production waste, with an increase in compressive strength of up to 64% compared to the samples without the AlF3 production waste. Deleterious natrite was shown to form in the samples without the production waste, which could be the reason for the lower observed mechanical properties of such samples. 相似文献
10.
Azhar Fakharuddin Marius Franckevičius Andrius Devižis Andrius Gelžinis Jevgenij Chmeliov Paul Heremans Vidmantas Gulbinas 《Advanced functional materials》2021,31(15):2010076
Heterogeneous organic-inorganic halide perovskites possess inherent non-uniformities in bandgap that are sometimes engineered and exploited on purpose, like in quasi-2D perovskites. In these systems, charge carrier and excitation energy migration to lower-bandgap sites are key processes governing luminescence. The question, which of them dominates in particular materials and under specific experimental conditions, still remains unanswered, especially when charge carriers comprise excitons. In this study transient absorption (TA) and transient photoluminescence (PL) techniques are combined to address the excited state dynamics in quasi-2D and other heterogeneous perovskite structures in broad temperature range, from room temperature down to 15 K. The data provide clear evidence that charge carrier transfer rather than energy migration dominates in heterogeneous quasi-2D perovskite films. 相似文献