Search results for "Signal processing"
showing 10 items of 2451 documents
A comprehensive survey of multi-view video summarization
2021
[EN] There has been an exponential growth in the amount of visual data on a daily basis acquired from single or multi-view surveillance camera networks. This massive amount of data requires efficient mechanisms such as video summarization to ensure that only significant data are reported and the redundancy is reduced. Multi-view video summarization (MVS) is a less redundant and more concise way of providing information from the video content of all the cameras in the form of either keyframes or video segments. This paper presents an overview of the existing strategies proposed for MVS, including their advantages and drawbacks. Our survey covers the genericsteps in MVS, such as the pre-proce…
Multicast delivery of file download services in 3G mobile networks with MBMS
2008
This article investigates the efficient transmission of file download services to several users simultaneously in 3G mobile networks with HSDPA (High-Speed Downlink Packet Access) and MBMS (Multimedia Broadcast Multicast Services). HSDPA supports high speed point-to-point (p-t-p) transmissions (up to several Mb/s), whereas with MBMS the same content can be transmitted with a point-to-multipoint (p-t-m) connection to multiple users in a unidirectional fashion. Multicast delivery can be implemented through only p-t-p transmissions with HSDPA, a single p-t-m transmission with MBMS, or using both jointly in a hybrid approach by employing HSDPA for error repair of the MBMS p-t-m transmission. We…
Real-time acquisition of wideband signals data using non-uniform sampling
2009
Wideband signal acquisition often faces a problem of bulk data recording. It is a critical factor in real-time systems. The paper discusses an approach that deals with this problem incorporating Digital Alias-free Signal Processing and Virtual Instrumentation technologies. Such combination is advantageous for real-time applications and useful in the development of measurement and software defined radio systems. Non-uniform sampling technique allows considerably decrease the data of wideband signals so, that they can be transferred in real-time to a typical PC through high-speed PCI Express communication interface. The experimental prototype system has been developed and obtained results are…
Elementary transformation analysis for Array-OL
2009
Array-OL is a high-level specification language dedicated to the definition of multidimentional intensive signal processing applications. It allows to specify both the task parallelism and the data parallelism of these applications on focusing on their complex multidimensional data access patterns. Several tools exist for implementing an Array-OL specification as a data parallel program. While Array-OL can be used directly, it is often convenient to be able to deduce part of the specification from a sequential version of the application. This paper proposes such an analysis and examines its feasibility and its limits.
Versatile metal-wire waveguides for broadband terahertz signal processing and multiplexing.
2022
AbstractWaveguides play a pivotal role in the full deployment of terahertz communication systems. Besides signal transporting, innovative terahertz waveguides are required to provide versatile signal-processing functionalities. Despite fundamental components, such as Bragg gratings, have been recently realized, they typically rely on complex hybridization, in turn making it extremely challenging to go beyond the most elementary functions. Here, we propose a universal approach, in which multiscale-structured Bragg gratings can be directly etched on metal-wires. Such an approach, in combination with diverse waveguide designs, allows for the realization of a unique platform with remarkable str…
A multimedia approach to the efficient implementation and use of emergency plans
2004
Because of the complexity of emergency procedures, the stressful situations during which they're executed, the emergency plan must be meticulously designed so that safety managers can quickly find needed information. Regardless of the complex procedures it describes and the trying situations where it would be used, the plan's success is always measured by how effective the evacuation is. Thus, safety-conscious organizations continually try to improve their emergency procedures and the way they present them in the emergency plan. Integrating incoming information during an emergency and correlating this information with the plan's procedures is a manual task for many safety managers. The dang…
Unificación de enseñanzas relacionadas con el Tratamiento Digital de Señales en la Universitat de València
2011
Teaching Digital Signal Processing (DSP) at the University of Valencia takes place in several subjects with a great overlap in contents. This work proposes an approach to unify DSP contents, so that it is possible to extract the contents corresponding with each subject. Moreover, the proposal is based on a repository that contains the common contents; the repository is hosted on a virtual learning environment, being Moodle and DotLRN the two platforms under study. The final implemented solution consists in an HTMLrepository formed by a number of basic teaching units. These basic units are packaged in a standard IMS-CP format, making up the materials of the different subjects.
High power analysis and design of dual-mode channel filters
2009
In this paper, we present two dual-mode channel filter topologies which are able to withstand more than 600 W in Ku-Band. The two different designs (one with elliptical cavities and the other one with rectangular cavities) implement the same transfer function: four order, elliptical response centered in 12 GHz, with 40 MHz bandwidth and two transmission zeros. It is shown that the critical dimensions for the power-handling of these filters are the dimensions of the input-output irises. In fact, in order to rigorously obtain these conclusions and to reach these high-power levels (including margins), it is essential to use the advanced numerical techniques described in the paper to predict th…
Assessing directional interactions among multiple physiological time series: The role of instantaneous causality
2012
This paper deals with the assessment of frequency domain causality in multivariate (MV) time series with significant instantaneous interactions. After providing different causality definitions, we introduce an extended MV autoregressive modeling approach whereby each definition is described in the time domain in terms of the model coefficients, and is quantified in the frequency domain by means of novel measures of directional connectivity. These measures are illustrated in a theoretical example showing how they reduce to known indexes when instantaneous causality is trivial, while they describe peculiar aspects of directional interaction in the presence of instantaneous causality. The appl…
Assessing Frequency Domain Causality in Cardiovascular Time Series with Instantaneous Interactions
2009
Summary Background: The partial directed coherence (PDC) is commonly used to assess in the frequency domain the existence of causal relations between two time series measured in conjunction with a set of other time series. Although the multivariate autoregressive (MVAR) model traditionally used for PDC computation accounts only for lagged effects, instantaneous effects cannot be neglected in the analysis of cardiovascular time series. Objectives: We propose the utilization of an extended MVAR model for PDC computation, in order to improve the evaluation of frequency domain causality in the presence of zero-lag correlations among multivariate time series. Methods: A procedure for the identif…