Search results for "frequency [modulation]"
showing 9 items of 569 documents
High-Frequency and Ultra-High Frequency Ultrasound: Musculoskeletal Imaging up to 70 MHz
2020
AbstractMusculoskeletal (MSK) ultrasound has well-established advantages, able to investigate very small structures with high resolution and a quick and real-time dynamic evaluation with the possibility of contralateral comparison. Thus ultrasound has kept its own almost exclusive fields of application in daily clinical practice, and it is considered the first-level imaging technique to assess tendons, bursae, and capsuloligamentous structures of small peripheral joints as well as peripheral nerves. Up to now, however, clinical MSK ultrasound imaging could not go beyond the first 1 to 2 cm under the skin, using high-frequency probes up to 18 to 20 MHz with spatial resolution just below mill…
Multi-domain Features of the Non-phase-locked Component of Interest Extracted from ERP Data by Tensor Decomposition
2020
The waveform in the time domain, spectrum in the frequency domain, and topography in the space domain of component(s) of interest are the fundamental indices in neuroscience research. Despite the application of time–frequency analysis (TFA) to extract the temporal and spectral characteristics of non-phase-locked component (NPLC) of interest simultaneously, the statistical results are not always expectedly satisfying, in that the spatial information is not considered. Complex Morlet wavelet transform is widely applied to TFA of event-related-potential (ERP) data, and mother wavelet (which should be firstly defined by center frequency and bandwidth (CFBW) before using the method to TFA of ERP…
Building and Testing a Comparative Interface on Northwest European Historical Parliamentary Debates : Relative Term Frequency Analysis of British Rep…
2022
Tensions between the people and parliament over representation are a normal feature of representative democracies. In this paper, we demonstrate how digital humanities analysis tools help in answering questions about the timing of debates on popular representation, tensions over its realization, and representatives’ changing perceptions on their parliamentary role. Our long-term approach to the conceptual history of political representation is based on the analysis of digitized parliamentary debates as nexuses of multi-sited political discourse. We combine computer-assisted distant and context-sensitive close reading to consider diachronic trends and synchronic political struggles surroundi…
High Frequency Data Acquisition System for Modelling the Impact of Visitors on the Thermo-Hygrometric Conditions of Archaeological Sites: A Casa di D…
2018
[EN] The characterization of the microclimatic conditions is fundamental for the preventive conservation of archaeological sites. In this context, the identification of the factors that influence the thermo-hygrometric equilibrium is key to determine the causes of cultural heritage deterioration. In this work, a characterization of the thermo-hygrometric conditions of Casa di Diana (Ostia Antica, Italy) is carried out analyzing the data of temperature and relative humidity recorded by a system of sensors with high monitoring frequency. Sensors are installed in parallel, calibrated and synchronized with a microcontroller. A data set of 793,620 data, arranged in a matrix with 66,135 rows and …
Time - frequency analysis in an open - air theater
2005
Acoustics measurements have been carried out along the steps of an ancient open-air theater. Source positions were fixed in several points in the orchestra while microphones, radially placed, were rotated sector by sector, spatially sampling the cavea. Measurements analysis allowed some speech and music sound quality index calculation for each source-microphone couple. Moving from the observation of acoustic quality indexes a time-frequency analysis of impulse response is presented in this paper. Timefrequency analysis of impulse response gives hints for new considerations about the sound field in this peculiar environment.
FPGA-piirien hyödyntäminen ultranopeassa automatisoidussa kaupankäynnissä
2012
Ultranopeassa automatisoidussa kaupankäynnissä (HFT) aika on rahaa ja jo millisekunnin etu kilpailijoihin nähden voi tuottaa suurenkin voiton. Optimoinnin HFT-järjestelmän joka osissa nopeuttavat järjestelmää. FPGA-piirien käyttö voi nopeuttaa HFT-järjestelmää huomattavasti. Erityisesti FPGA-piiri soveltuu markkinasyötteen käsittelyyn. FPGA-piireillä savutetaan 5-22 kertainen nopeus yleiskäyttöiseen suorittimeen nähden markkinasyötteen käsittelyssä In high-frequency trading (HFT) time is money. Even a one millisecond advance to other traders can bring huge wins to the HFT system. Optimazations in different parts of the HFT system can make system faster. Using FPGAs signifacantly decreases l…
Sensitivity Analysis and Frequency Dynamics of Grid-Connected Converters with Virtual Inertia
2021
For the participation in the frequency control of the system, power converters can be controlled with different strategies and methods, sharing the common concept of virtual inertia capability. In this work, a sensitivity analysis of two main categories of converter controls with virtual inertia is presented. The considered schemes are a grid-following current vector control with additional virtual inertia block and a grid-forming control scheme based on virtual synchronous machine concept. A proper basis for the comparison is first assessed providing an analytical correlation between the control parameters of the two schemes. For the two control strategies, the sensitivity analysis of the …
Energy Efficient Optimization for Wireless Virtualized Small Cell Networks With Large-Scale Multiple Antenna
2017
Wireless network virtualization is envisioned as a promising framework to provide efficient and customized services for next-generation wireless networks. In wireless virtualized networks (WVNs), limited radio resources are shared among different services providers for providing services to different users with heterogeneous demands. In this paper, we propose a resource allocation scheme for an orthogonal frequency division multiplexing-based WVN, where one small cell base station equipped with a large number of antennas serves the users with different service requirements. In particular, with the objective to obtain the energy efficiency in the uplink, a joint power, subcarrier, and antenn…
High frequency data entry: statistical findings at high frequency
2010
We introduce some of the most common types of high-frequency financial data: tick-by-tick data, trade andquote data, order bookdata, andmarket member data. We describe the types of variables that are usually available in the most popular high-frequency financial databases. We discuss the issues related to the handling of these data, including cleaning protocols, timing issues, and issues related to data size. We then briefly consider the issues related to the stylized facts detected in the empirical analysis of high- frequency data. Specifically, we consider (i) the irregular temporal spacing of the events at high frequency and its relevance for the econometric modeling of financial variables, (…