938 resultados para System-based
Resumo:
A prototype fibre-optic system using interferometric wavelength-shift detection, capable of multiplexing up to 32 fibre-optic Bragg grating strain and temperature sensors with identical characteristics, has been demonstrated. This system is based on a spatially multiplexed scheme for use with fibre-based low-coherence interferometric sensors, reported previously. Four fibre-optic Bragg grating channels using the same fibre grating have been demonstrated for measuring quasi-static strain and temperature.
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It is proposed an agent approach for creation of intelligent intrusion detection system. The system allows detecting known type of attacks and anomalies in user activity and computer system behavior. The system includes different types of intelligent agents. The most important one is user agent based on neural network model of user behavior. Proposed approach is verified by experiments in real Intranet of Institute of Physics and Technologies of National Technical University of Ukraine "Kiev Polytechnic Institute”.
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We experimentally demonstrated a highly sensitive twist sensor system based on a 45° and an 81° tilted fibre grating (TFG). The 81°-TFG has a set of dual-peaks that are due to the birefringence induced by its extremely tilted structure. When the 81°-TFG subjected to twist, the coupling to the two peaks would interchange from each other, providing a mechanism to measure and monitor the twist. We have investigated the performance of the sensor system by three interrogation methods (spectral, power-measurement and voltage-measurement). The experimental results clearly show that the 81°-TFG and the 45°-TFG could be combined forming a full fibre twist sensor system capable of not just measuring the magnitude but also recognising the direction of the applied twist.
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Architecture and learning algorithm of self-learning spiking neural network in fuzzy clustering task are outlined. Fuzzy receptive neurons for pulse-position transformation of input data are considered. It is proposed to treat a spiking neural network in terms of classical automatic control theory apparatus based on the Laplace transform. It is shown that synapse functioning can be easily modeled by a second order damped response unit. Spiking neuron soma is presented as a threshold detection unit. Thus, the proposed fuzzy spiking neural network is an analog-digital nonlinear pulse-position dynamic system. It is demonstrated how fuzzy probabilistic and possibilistic clustering approaches can be implemented on the base of the presented spiking neural network.
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Liquid-level sensing technologies have attracted great prominence, because such measurements are essential to industrial applications, such as fuel storage, flood warning and in the biochemical industry. Traditional liquid level sensors are based on electromechanical techniques; however they suffer from intrinsic safety concerns in explosive environments. In recent years, given that optical fiber sensors have lots of well-established advantages such as high accuracy, costeffectiveness, compact size, and ease of multiplexing, several optical fiber liquid level sensors have been investigated which are based on different operating principles such as side-polishing the cladding and a portion of core, using a spiral side-emitting optical fiber or using silica fiber gratings. The present work proposes a novel and highly sensitive liquid level sensor making use of polymer optical fiber Bragg gratings (POFBGs). The key elements of the system are a set of POFBGs embedded in silicone rubber diaphragms. This is a new development building on the idea of determining liquid level by measuring the pressure at the bottom of a liquid container, however it has a number of critical advantages. The system features several FBG-based pressure sensors as described above placed at different depths. Any sensor above the surface of the liquid will read the same ambient pressure. Sensors below the surface of the liquid will read pressures that increase linearly with depth. The position of the liquid surface can therefore be approximately identified as lying between the first sensor to read an above-ambient pressure and the next higher sensor. This level of precision would not in general be sufficient for most liquid level monitoring applications; however a much more precise determination of liquid level can be made by linear regression to the pressure readings from the sub-surface sensors. There are numerous advantages to this multi-sensor approach. First, the use of linear regression using multiple sensors is inherently more accurate than using a single pressure reading to estimate depth. Second, common mode temperature induced wavelength shifts in the individual sensors are automatically compensated. Thirdly, temperature induced changes in the sensor pressure sensitivity are also compensated. Fourthly, the approach provides the possibility to detect and compensate for malfunctioning sensors. Finally, the system is immune to changes in the density of the monitored fluid and even to changes in the effective force of gravity, as might be obtained in an aerospace application. The performance of an individual sensor was characterized and displays a sensitivity (54 pm/cm), enhanced by more than a factor of 2 when compared to a sensor head configuration based on a silica FBG published in the literature, resulting from the much lower elastic modulus of POF. Furthermore, the temperature/humidity behavior and measurement resolution were also studied in detail. The proposed configuration also displays a highly linear response, high resolution and good repeatability. The results suggest the new configuration can be a useful tool in many different applications, such as aircraft fuel monitoring, and biochemical and environmental sensing, where accuracy and stability are fundamental. © (2015) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
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An enhanced fiber sensing system used for distributed bending and key-position sensing is reported by integrating WFBGs, LPFG and OTDR, which also achieves strain and temperature sensitivities up to 0.047mv/με and 0.675mv/°C respectively. © 2014 OSA.
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In view of the increasingly complexity of services logic and functional requirements, a new system architecture based on SOA was proposed for the equipment remote monitoring and diagnosis system. According to the design principles of SOA, different levels and different granularities of services logic and functional requirements for remote monitoring and diagnosis system were divided, and a loosely coupled web services system was built. The design and implementation schedule of core function modules for the proposed architecture were presented. A demo system was used to validate the feasibility of the proposed architecture.
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Incomplete pairwise comparison matrix was introduced by Harker in 1987 for the case in which the decision maker does not fill in the whole matrix completely due to, e.g., time limitations. However, incomplete matrices occur in a natural way even if the decision maker provides a completely filled in matrix in the end. In each step of the total n(n–1)/2, an incomplete pairwise comparison is given, except for the last one where the matrix turns into complete. Recent results on incomplete matrices make it possible to estimate inconsistency indices CR and CM by the computation of tight lower bounds in each step of the filling in process. Additional information on ordinal inconsistency is also provided. Results can be applied in any decision support system based on pairwise comparison matrices. The decision maker gets an immediate feedback in case of mistypes, possibly causing a high level of inconsistency.
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With the exponential increasing demands and uses of GIS data visualization system, such as urban planning, environment and climate change monitoring, weather simulation, hydrographic gauge and so forth, the geospatial vector and raster data visualization research, application and technology has become prevalent. However, we observe that current web GIS techniques are merely suitable for static vector and raster data where no dynamic overlaying layers. While it is desirable to enable visual explorations of large-scale dynamic vector and raster geospatial data in a web environment, improving the performance between backend datasets and the vector and raster applications remains a challenging technical issue. This dissertation is to implement these challenging and unimplemented areas: how to provide a large-scale dynamic vector and raster data visualization service with dynamic overlaying layers accessible from various client devices through a standard web browser, and how to make the large-scale dynamic vector and raster data visualization service as rapid as the static one. To accomplish these, a large-scale dynamic vector and raster data visualization geographic information system based on parallel map tiling and a comprehensive performance improvement solution are proposed, designed and implemented. They include: the quadtree-based indexing and parallel map tiling, the Legend String, the vector data visualization with dynamic layers overlaying, the vector data time series visualization, the algorithm of vector data rendering, the algorithm of raster data re-projection, the algorithm for elimination of superfluous level of detail, the algorithm for vector data gridding and re-grouping and the cluster servers side vector and raster data caching.
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The objective of this study was to develop a GIS-based multi-class index overlay model to determine areas susceptible to inland flooding during extreme precipitation events in Broward County, Florida. Data layers used in the method include Airborne Laser Terrain Mapper (ALTM) elevation data, excess precipitation depth determined through performing a Soil Conservation Service (SCS) Curve Number (CN) analysis, and the slope of the terrain. The method includes a calibration procedure that uses "weights and scores" criteria obtained from Hurricane Irene (1999) records, a reported 100-year precipitation event, Doppler radar data and documented flooding locations. Results are displayed in maps of Eastern Broward County depicting types of flooding scenarios for a 100-year, 24-hour storm based on the soil saturation conditions. As expected the results of the multi-class index overlay analysis showed that an increase for the potential of inland flooding could be expected when a higher antecedent moisture condition is experienced. The proposed method proves to have some potential as a predictive tool for flooding susceptibility based on a relatively simple approach.
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2016 is the outbreak year of the virtual reality industry. In the field of virtual reality, 3D surveying plays an important role. Nowadays, 3D surveying technology has received increasing attention. This project aims to establish and optimize a WebGL three-dimensional broadcast platform combined with streaming media technology. It takes streaming media server and panoramic video broadcast in browser as the application background. Simultaneously, it discusses about the architecture from streaming media server to panoramic media player and analyzing relevant theory problem. This paper focuses on the debugging of streaming media platform, the structure of WebGL player environment, different types of ball model analysis, and the 3D mapping technology. The main work contains the following points: Initially, relay on Easy Darwin open source streaming media server, built a streaming service platform. It can realize the transmission from RTSP stream to streaming media server, and forwards HLS slice video to clients; Then, wrote a WebGL panoramic video player based on Three.js lib with JQuery browser playback controls. Set up a HTML5 panoramic video player; Next, analyzed the latitude and longitude sphere model which from Three.js library according to WebGL rendering method. Pointed out the drawbacks of this model and the breakthrough point of improvement; After that, on the basis of Schneider transform principle, established the Schneider sphere projection model, and converted the output OBJ file to JS file for media player reading. Finally implemented real time panoramic video high precision playing without plugin; At last, I summarized the whole project. Put forward the direction of future optimization and extensible market.
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At present, in large precast concrete enterprises, the management over precast concrete component has been chaotic. Most enterprises take labor-intensive manual input method, which is time consuming and laborious, and error-prone. Some other slightly better enterprises choose to manage through bar-code or printing serial number manually. However, on one hand, this is also labor-intensive, on the other hand, this method is limited by external environment, making the serial number blur or even lost, and also causes a big problem on production traceability and quality accountability. Therefore, to realize the enterprise’s own rapid development and cater to the needs of the time, to achieve the automated production management has been a big problem for a modern enterprise. In order to solve the problem, inefficiency in production and traceability of the products, this thesis try to introduce RFID technology into the production of PHC tubular pile. By designing a production management system of precast concrete components, the enterprise will achieve the control of the entire production process, and realize the informatization of enterprise production management. RFID technology has been widely used in many fields like entrance control, charge management, logistics and so on. RFID technology will adopt passive RFID tag, which is waterproof, shockproof, anti-interference, so it’s suitable for the actual working environment. The tag will be bound to the precast component steel cage (the structure of the PHC tubular pile before the concrete placement), which means each PHC tubular pile will have a unique ID number. Then according to the production procedure, the precast component will be performed with a series of actions, put the steel cage into the mold, mold clamping, pouring concrete (feed), stretching, centrifugalizing, maintenance, mold removing, welding splice. In every session of the procedure, the information of the precast components can be read through a RFID reader. Using a portable smart device connected to the database, the user can check, inquire and management the production information conveniently. Also, the system can trace the production parameter and the person in charge, realize the traceability of the information. This system can overcome the disadvantages in precast components manufacturers, like inefficiency, error-prone, time consuming, labor intensity, low information relevance and so on. This system can help to improve the production management efficiency, and can produce a good economic and social benefits, so, this system has a certain practical value.
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Abstract-The immune system is a complex biological system with a highly distributed, adaptive and self-organising nature. This paper presents an artificial immune system (AIS) that exploits some of these characteristics and is applied to the task of film recommendation by collaborative filtering (CF). Natural evolution and in particular the immune system have not been designed for classical optimisation. However, for this problem, we are not interested in finding a single optimum. Rather we intend to identify a sub-set of good matches on which recommendations can be based. It is our hypothesis that an AIS built on two central aspects of the biological immune system will be an ideal candidate to achieve this: Antigen - antibody interaction for matching and antibody - antibody interaction for diversity. Computational results are presented in support of this conjecture and compared to those found by other CF techniques.
Resumo:
The immune system is a complex biological system with a highly distributed, adaptive and self-organising nature. This paper presents an Artificial Immune System (AIS) that exploits some of these characteristics and is applied to the task of film recommendation by Collaborative Filtering (CF). Natural evolution and in particular the immune system have not been designed for classical optimisation. However, for this problem, we are not interested in finding a single optimum. Rather we intend to identify a sub-set of good matches on which recommendations can be based. It is our hypothesis that an AIS built on two central aspects of the biological immune system will be an ideal candidate to achieve this: Antigen-antibody interaction for matching and idiotypic antibody-antibody interaction for diversity. Computational results are presented in support of this conjecture and compared to those found by other CF techniques.
Resumo:
The immune system is a complex biological system with a highly distributed, adaptive and self-organising nature. This paper presents an Artificial Immune System (AIS) that exploits some of these characteristics and is applied to the task of film recommendation by Collaborative Filtering (CF). Natural evolution and in particular the immune system have not been designed for classical optimisation. However, for this problem, we are not interested in finding a single optimum. Rather we intend to identify a sub-set of good matches on which recommendations can be based. It is our hypothesis that an AIS built on two central aspects of the biological immune system will be an ideal candidate to achieve this: Antigen-antibody interaction for matching and idiotypic antibody-antibody interaction for diversity. Computational results are presented in support of this conjecture and compared to those found by other CF techniques.