Relevant bibliographies by topics / Frequency-to-time transformation

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  1. Journal articles
  2. Dissertations / Theses
  3. Books
  4. Book chapters
  5. Conference papers

Academic literature on the topic 'Frequency-to-time transformation'

Author: Grafiati
Published: 4 June 2021
Last updated: 1 February 2022

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Journal articles on the topic "Frequency-to-time transformation"

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Shankar, S. "Talking Time to Frequency Transformation." IEEE Potentials 31, no. 6 (November 2012): 16–21. http://dx.doi.org/10.1109/mpot.2012.2201336.

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Ménager, L., J. L. Le Gouët, and I. Lorgeré. "Time-to-frequency Fourier transformation with photon echoes." Optics Letters 26, no. 18 (September 15, 2001): 1397. http://dx.doi.org/10.1364/ol.26.001397.

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Cho, In-Ky, Rae-Yeong Kim, Kwang-Beom Ko, and Young-June You. "Frequency-to-time Transformation by a Diffusion Expansion Method." Geophysics and Geophysical Exploration 17, no. 3 (August 31, 2014): 129–36. http://dx.doi.org/10.7582/gge.2014.17.3.129.

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Palushani, E., H. C. H. Mulvad, M. Galili, Hao Hu, L. K. Oxenlowe, A. T. Clausen, and P. Jeppesen. "OTDM-to-WDM Conversion Based on Time-to-Frequency Mapping by Time-Domain Optical Fourier Transformation." IEEE Journal of Selected Topics in Quantum Electronics 18, no. 2 (March 2012): 681–88. http://dx.doi.org/10.1109/jstqe.2011.2131121.

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Jin, Lin, Sun Yuan-zhang, Poul Sorensen, Li Guo-jie, and Gao Weng-zhong. "Method for Assessing Grid Frequency Deviation Due to Wind Power Fluctuation Based on “Time-Frequency Transformation”." IEEE Transactions on Sustainable Energy 3, no. 1 (January 2012): 65–73. http://dx.doi.org/10.1109/tste.2011.2162639.

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Tehrani, Ali Moradi, Evert Slob, and Wim Mulder. "Quasi-analytical method for frequency-to-time conversion in CSEM applications." GEOPHYSICS 77, no. 5 (September 1, 2012): E357—E363. http://dx.doi.org/10.1190/geo2011-0432.1.

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Frequency-to-time transformations are of interest to controlled-source electromagnetic methods when time-domain data are inverted for a subsurface resistivity model by numerical frequency-domain modeling at a selected, small number of frequencies whereas the data misfit is determined in the time domain. We propose an efficient, Prony-type method using frequency-domain diffusive-field basis functions for which the time-domain equivalents are known. Diffusive fields are characterized by an exponential part whose argument is proportional to the square root of frequency and a part that is polynomial in integer powers of the square root of frequency. Data at a limited number of frequencies suffice for the transformation back to the time. In the exponential part, several diffusion-time values must be chosen. Once a suitable range of diffusion-time values are found, the method is quite robust in the number of values used. The highest power in the polynomial part can be determined from the source and receiver type. When the frequency-domain data are accurately approximated by the basis functions, the time-domain result is also accurate. This method is accurate over a wider time range than other methods and has the correct late-time asymptotic behavior. The method works well for data computed for layered and 3D subsurface models.
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Ruge, Peter, Ediansjah Zulkifli, and Carolin Birk. "Symmetric matrix-valued frequency to time transformation for unbounded domains applied to infinite beams." Computers & Structures 84, no. 28 (November 2006): 1815–26. http://dx.doi.org/10.1016/j.compstruc.2006.04.006.

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Gao, Ben-Qing. "A new principle technic for the transformation from frequency domain to time domain." AIP Advances 7, no. 3 (March 2017): 035316. http://dx.doi.org/10.1063/1.4979327.

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Liu, Ji, Daning Zhang, Xinlao Wei, and Hamid Reza Karimi. "Transformation Algorithm of Dielectric Response in Time-Frequency Domain." Mathematical Problems in Engineering 2014 (2014): 1–7. http://dx.doi.org/10.1155/2014/547105.

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A transformation algorithm of dielectric response from time domain to frequency domain is presented. In order to shorten measuring time of low or ultralow frequency dielectric response characteristics, the transformation algorithm is used in this paper to transform the time domain relaxation current to frequency domain current for calculating the low frequency dielectric dissipation factor. In addition, it is shown from comparing the calculation results with actual test data that there is a coincidence for both results over a wide range of low frequencies. Meanwhile, the time domain test data of depolarization currents in dry and moist pressboards are converted into frequency domain results on the basis of the transformation. The frequency domain curves of complex capacitance and dielectric dissipation factor at the low frequency range are obtained. Test results of polarization and depolarization current (PDC) in pressboards are also given at the different voltage and polarization time. It is demonstrated from the experimental results that polarization and depolarization current are affected significantly by moisture contents of the test pressboards, and the transformation algorithm is effective in ultralow frequency of 10−3 Hz. Data analysis and interpretation of the test results conclude that analysis of time-frequency domain dielectric response can be used for assessing insulation system in power transformer.
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Ozaktas, H. M., N. Erkaya, and M. A. Kutay. "Effect of fractional Fourier transformation on time-frequency distributions belonging to the Cohen class." IEEE Signal Processing Letters 3, no. 2 (February 1996): 40–41. http://dx.doi.org/10.1109/97.484211.

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Dissertations / Theses on the topic "Frequency-to-time transformation"

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Zulkifli, Ediansjah. "Consistent description of radiation damping in transient soil-structure interaction." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2008. http://nbn-resolving.de/urn:nbn:de:bsz:14-ds-1217499921691-59045.

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Dynamic soil-structure interaction problems are characterized by an unbounded soil-domain and thus by radiation damping. This radiation damping arises due to wave propagation from the excited structure into the subsoil and may lead to a reduction of the structural response. A consistent description of this radiation damping has been carried out by means of different concepts. A widely used approach truncates the unbounded medium by a special kind of absorbing boundaries which are free of artificial reflection. The resulting finite domain can be treated as usually by finite elements. In this report, an alternative method to represent an unbounded medium in a dynamic analysis is presented. In principle, it is a conjunction of the boundary element method (BEM) in the frequency domain to reproduce the far-field and the finite element method (FEM) in the time domain to analyze the near-field. This alternative procedure avoids the introduction of any artificial boundaries. The procedure is based on a rational approximation of the dynamic stiffness of the unbounded domain in the frequency-domain. In this report, the dynamic stiffness of the unbounded domain is obtained from the BEM. The matrix-valued coefficients of the rational approximation function are determined by means of a least-square procedure. The time-domain representation is achieved by splitting the rational force-displacement relation into a series of linear functions in the frequency-domain corresponding with first order differential equations in the time-domain. This splitting process has been demonstrated as numerically effective and in addition, no Fourier transformation is necessary. In this thesis, dynamic soil-structure interaction problems with a relatively large number of degrees of freedom have been examined. These degrees of freedom arise from the discretization of the coupling interface, internal variables from the splitting procedure and from modeling the structure. The new method is especially suitable for systems with transient excitations as arising from rotating machines at startup and shutdown. The theoretical part of the thesis contains elements of system theory and discusses particularly stability problems arising from the rational approximation. The practical part presents a large amount of convergence studies and numerical results for layered soil and finally represents the propagation damping as a kind of damping ratio which is typically used in elementary structural dynamics
In der Dynamik der Boden-Bauwerk-Interaktion wird der Boden in vielen Fällen durch ein unbegrenztes elastisches Medium beschrieben, wodurch das Phänomen der Abstrahldämpfung begründet wird. Diese Dämpfung entsteht durch Energietransfer von der erregten Struktur in den Boden durch Wellenausbreitung und reduziert somit die Strukturschwingungen. Um das infinite Bodengebiet dennoch durch finite Elemente beschreiben zu können, werden üblicherweise als Hilfsmaßnahme künstliche sogenannte absorbierende Ränder eingeführt. In dieser Arbeit wird eine alternative Methode zur Darstellung des unbegrenzten Mediums in der Dynamik vorgelegt. Im Prinzip handelt es sich um eine Kopplung der Rand-Element-Methode (REM) für den unendlichen Boden (das sogenannte Fernfeld) im Frequenzbereich und der Finite-Element-Methode (FEM) für das Nahfeld im Zeitbereich. Dieses alternative Verfahren vermeidet die Einführung künstlicher Ränder. Das Verfahren basiert auf einer rationalen Beschreibung der dynamischen Steifigkeit des Fernfeldes im Frequenzbereich. Diese Steifigkeit wird in der vorliegenden Arbeit durch die Rand-Element-Methode erzeugt. Die Matrix-wertigen Koeffizienten der rationalen Frequenzfunktion werden durch Minimierung des Fehlerquadrates berechnet. Die Transformation dieser Frequenzdarstellung in den Zeitbereich gelingt durch algebraische Überführung der rationalen Funktion in ein in der Frequenz lineares Hypersystem mit einer zugeordneten Zustandsgleichung erste Ordnung im Zeitbereich. Dieser Prozess hat sich als numerisch effektiv erwiesen und erfordert darüberhinaus keine Fourier-Transformation. Das entwickelte Vorgehen wird in dieser Arbeit an Problemen der dynamischen Boden-Bauwerk-Interaktion mit einer großen Anzahl von Freiheitsgraden erprobt. Diese Freiheitsgrade folgen aus der Diskretisierung in der Koppelfuge zwischen Boden und Struktur, der Diskretisierung der Struktur selbst und aus der Überführung in das Hypersystem mittels interner Variablen. Das neue Verfahren eignet sich insbesondere für Systeme mit transienter Erregung, wie sie beim An- und Auslaufen von Rotationsmaschinen ensteht. Der theoretische Teil der Arbeit wird geprägt durch Elemente der Systemtheorie und setzt sich zudem mit typischen Stabilitätsproblemen auseinander, die aus der rationalen Beschreibung entstehen. Der praktische Teil präsentiert Konvergenzstudien und numerische Ergebnisse für Boden-Bauwerk- Interaktionsprobleme mit geschichtetem Boden bei transienter Erregung mit Resonanzdurchlauf. Zudem gelingt eine Darstellung der Abstrahldämpfung in Form des Dämpfungsgrades D, wie er in der klassischen Strukturdynamik verwendet wird
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Niethammer, Marc. "Application of time frequency representations to characterize ultrasonic signals." Thesis, Georgia Institute of Technology, 1999. http://hdl.handle.net/1853/19005.

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Sayyah, Jahromi Mohammad Reza Information Technology &amp Electrical Engineering Australian Defence Force Academy UNSW. "Efficient broadband antenna array processing using the discrete fourier form transform." Awarded by:University of New South Wales - Australian Defence Force Academy. School of Information Technology and Electrical Engineering, 2005. http://handle.unsw.edu.au/1959.4/38690.

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Processing of broadband signals induced on an antenna array using a tapped delay line filter and a set of steering delays has two problems. Firstly one needs to manipulate large matrices to estimate the filter coefficients. Secondly the use of steering delays is not only cumbersome but implementation errors cause loss of system performance. This thesis looks at both of these problems and presents elegant solutions by developing and studying a design method referred to as the DFT method, which does not require steering delays and is computationally less demanding compared to existing methods. Specifically the thesis studies and compares the performance of a time domain element space beamformer using the proposed method and that using an existing method, and develops the DFT method when the processor is implemented in partitioned form. The study presented in the thesis shows that the processors using the DFT method are robust to look direction errors and require less computation than that using the existing method for comparable performance. The thesis further introduces a broadband beamformer design which does not require any steering delays between the sensors and the tapped delay line section as is presently the case. It has the capability of steering the array in an arbitrary direction with a specified frequency response in the look direction while canceling unwanted uncorrelated interferences. The thesis presents and compares the performance of a number of techniques to synthesize an antenna pattern of a broadband array. These techniques are designed to produce isolated point nulls as well as broad sector nulls and to eliminate the need for the steering delays. Two of the pattern synthesis techniques presented in the thesis allow optimization against unwanted interferences in unknown directions. The techniques allow formulation of a beamforming problem such that the processor is not only able to place nulls in specified directions but also able to cancel directional interferences in unknown directions along with a specified frequency response in the look direction over a band of interest. The thesis also presents a set of directional constraints such that one does not need steering delays and an array can be constrained in an arbitrary direction with a specified frequency response. The constraints presented in the thesis are simple to implement. Based on these constraints a pattern synthesis technique for broadband antenna array is also presented.
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Books on the topic "Frequency-to-time transformation"

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K, Brodzik Andrzej, and Tolimieri Richard 1940-, eds. Ideal sequence design in time-frequency space: Applications to radar, sonar, and communication systems. Boston, Mass: Birkhäuser, 2009.

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High resolution frequency to time domain transformations applied to the stepped carrier MRIS measurements: Final technical report. [Washington, DC: National Aeronautics and Space Administration, 1992.

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High resolution frequency to time domain transformations applied to the stepped carrier MRIS measurements: Final technical report. [Washington, DC: National Aeronautics and Space Administration, 1992.

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Herring, Christina. Neuromodulation in Psychiatric Disorders. Edited by Anthony J. Bazzan and Daniel A. Monti. Oxford University Press, 2018. http://dx.doi.org/10.1093/med/9780190690557.003.0013.

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Quantitative electroencephalogram (qEEG) is the transformation of the EEG by spectral analysis in which the amount of electrical activity at a particular frequency is determined and compared against a normative data base. EEG findings are specific for different psychiatric problems and help reveal brain abnormalities associated with psychological symptoms. Repetitive transcranial magnetic stimulation (rTMS) is a system of delivering multiple pulses within a short time period that induce changes that outlast the stimulation period. Operant conditioning involves providing a reward to increase the probability of a certain behavior. Neurofeedback involves recording, analyzing, and presenting results of qEEG analyses in near real-time to patients in order to promote changes in brain electrical activity. This chapter reviews how neuromodulation works both clinically and from a neurophysiological perspective. This chapter also reviews current clinical data on the use of neuromodulation approaches for improving mental health and well-being.
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Dube, Opha Pauline. Climate Policy and Governance across Africa. Oxford University Press, 2016. http://dx.doi.org/10.1093/acrefore/9780190228620.013.605.

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This is an advance summary of a forthcoming article in the Oxford Research Encyclopedia of Climate Science. Please check back later for the full article.Africa, a continent with the largest number of countries falling under the category of Least Developed Countries (LDCs), remains highly dependent on rain-fed agriculture that suffers from low intake of water, exacerbating the vulnerability to climate variability and anthropogenic climate change. The increasing frequency and severity of climate extremes impose major strains on the economies of these countries. The loss of livelihoods due to interaction of climate change with existing stressors is elevating internal and cross-border migration. The continent is experiencing rapid urbanization, and its cities represent the most vulnerable locations to climate change due in part to incapacitated local governance. Overall, the institutional capacity to coordinate, regulate, and facilitate development in Africa is weak. The general public is less empowered to hold government accountable. The rule of law, media, and other watchdog organizations, and systems of checks and balances are constrained in different ways, contributing to poor governance and resulting in low capacity to respond to climate risks.As a result, climate policy and governance are inseparable in Africa, and capacitating the government is as essential as establishing climate policy. With the highest level of vulnerability to climate change compared with the rest of the world, governance in Africa is pivotal in crafting and implementing viable climate policies.It is indisputable that African climate policy should focus first and foremost on adaptation to climate change. It is pertinent, therefore, to assess Africa’s governance ability to identify and address the continent’s needs for adaptation. One key aspect of effective climate policy is access to up-to-date and contextually relevant information that encompasses indigenous knowledge. African countries have endeavored to meet international requirements for reports such as the National Communications on Climate Change Impacts and Vulnerabilities and the National Adaptation Programmes of Action (NAPAs). However, the capacity to deliver on-time quality reports is lacking; also the implementation, in particular integration of adaptation plans into the overall development agenda, remains a challenge. There are a few successes, but overall adaptation operates mainly at project level. Furthermore, the capacity to access and effectively utilize availed international resources, such as extra funding or technology transfer, is limited in Africa.While the continent is an insignificant source of emissions on a global scale, a more forward looking climate policy would require integrating adaptation with mitigation to put in place a foundation for transformation of the development agenda, towards a low carbon driven economy. Such a futuristic approach calls for a comprehensive and robust climate policy governance that goes beyond climate to embrace the Sustainable Development Goals Agenda 2030. Both governance and climate policy in Africa will need to be viewed broadly, encompassing the process of globalization, which has paved the way to a new geological epoch, the Anthropocene. The question is, what should be the focus of climate policy and governance across Africa under the Anthropocene era?
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Book chapters on the topic "Frequency-to-time transformation"

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Metral, E., G. Rumolo, and W. Herr. "Impedance and Collective Effects." In Particle Physics Reference Library, 105–81. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-34245-6_4.

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AbstractAs the beam intensity increases, the beam can no longer be considered as a collection of non-interacting single particles: in addition to the “single-particle phenomena”, “collective effects” become significant. At low intensity a beam of charged particles moves around an accelerator under the Lorentz force produced by the “external” electromagnetic fields (from the guiding and focusing magnets, RF cavities, etc.). However, the charged particles also interact with themselves (leading to space charge effects) and with their environment, inducing charges and currents in the surrounding structures, which create electromagnetic fields called wake fields. In the ultra-relativistic limit, causality dictates that there can be no electromagnetic field in front of the beam, which explains the term “wake”. It is often useful to examine the frequency content of the wake field (a time domain quantity) by performing a Fourier transformation on it. This leads to the concept of impedance (a frequency domain quantity), which is a complex function of frequency. The charged particles can also interact with other charged particles present in the accelerator (leading to two-stream effects, and in particular to electron cloud effects in positron/hadron machines) and with the counter-rotating beam in a collider (leading to beam–beam effects). As the beam intensity increases, all these “perturbations” should be properly quantified and the motion of the charged particles will eventually still be governed by the Lorentz force but using the total electromagnetic fields, which are the sum of the external and perturbation fields. Note that in some cases a perturbative treatment is not sufficient and the problem has to be solved self consistently. These perturbations can lead to both incoherent (i.e. of a single particle) and coherent (i.e. of the centre of mass) effects, in the longitudinal and in one or both transverse directions, leading to beam quality degradation or even partial or total beam losses. Fortunately, stabilising mechanisms exist, such as Landau damping, electronic feedback systems and linear coupling between the transverse planes (as in the case of a transverse coherent instability, one plane is usually more critical than the other).
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Gergen, Kenneth J., and Scherto R. Gill. "Relational Evaluation and Educational Transformation." In Beyond the Tyranny of Testing, 155–80. Oxford University Press, 2020. http://dx.doi.org/10.1093/oso/9780190872762.003.0008.

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Practices of dialogue, collaboration, and participatory action appear with increasing frequency across the landscape of contemporary education. Of particular significance is their presence in emerging practices of curriculum design and pedagogy. In this chapter the authors first explore the close relationship of these developments to relational evaluation. Uniting relationally sensitive practices across these three domains would pave the way to a major transformation in education. Objections to practices of relational evaluation are then addressed, including such issues as time constraints, rigor, standards, and the need for gateways to higher education. Finally we touch on two major movements in cultural life on which the possibilities of educational transformation will depend. Impeding educational change are the creeping forces of market driven visions of organizational functioning. In contrast are the consequences of major innovations in information and communication technology. Here we find the unleashing of enormous learning potential. Such developments invite the full flourishing of a relational orientation to education.
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Ahmad, Rizwan, and Ramaraju Sudarshana. "Transformation in Vegetation and Urban Sprawl in Gotan and Surrounding." In Examining International Land Use Policies, Changes, and Conflicts, 111–24. IGI Global, 2021. http://dx.doi.org/10.4018/978-1-7998-4372-6.ch006.

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The main driving forces associated with transformation of vegetation cover and urban sprawl, are undoubtedly climate change and human intervention. Finding the truth behind transformation of Gotan, Rajasthan Landsat TM/ETM+ data of the years 1987,1990, 1995, 2000, 2003, 2010, 2015, and 2018 were used. These time series data comprising total of nine scenes were selected to measure the urban and green cover transformation in the past four decades. Landsat TM/ETM+ data were used because it is inexpensive, with high monitoring frequency and covers large areas. The Normalized Difference Vegetation Index (NDVI) of 1987–2018, derived from the remote sensing dataset along with the application of statistical methods and GIS techniques, were used to quantify vegetation cover change. The results show that human-induced factors can explain most variations at sites with significant cover change. It has been a well-known fact that sustainable development presents a system in order to accomplish economic growth, bring about social justice, implement environmental awareness and most certainly the fortification of government sector.
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alZahir, Saif. "A Fast New Rotation Insensitive WP-Based Method for Image Indexing and Retrieval." In Computer Vision, 1926–39. IGI Global, 2018. http://dx.doi.org/10.4018/978-1-5225-5204-8.ch082.

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Large multimedia databases and digital image archival systems are being created in government, academia, military, hospitals, digital libraries, and businesses. Efficient methods to retrieve images from such large databases have become indispensable. In this chapter, the authors present a novel Wavelet Packet (WP)-based method for image identification and retrieval that enables the recovery of the original image from a database even if the image has been subjected to geometric transformations such as size-conserving rotation or flipping operations. The proposed method uses the correlation of wavelet packet coefficients to create an image signature. This signature is comprised of two parts. The first part is a short signature, SS, that represents the location of specific values of the WP coefficient correlations in each frequency band. The second portion is the basis signature of the image, which is a long signature, LS, of 1296 correlation points produced by summing up the correlation values along all frequency bands. Computer simulation results show that the method is extremely fast, has a perfect image retrieval rates (100%), and perfect geometric transformations recognition, if any. In addition, the simulation results show that target images are perfectly identified from an image database of 7500 image signatures within a short period of time (nearly 8 seconds on the average). This method is robust against geometric transformation and requires minimal data transfer and can be used for online image retrieval.
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alZahir, Saif. "A Fast New Rotation Insensitive WP-Based Method for Image Indexing and Retrieval." In Computer Vision and Image Processing in Intelligent Systems and Multimedia Technologies, 234–46. IGI Global, 2014. http://dx.doi.org/10.4018/978-1-4666-6030-4.ch013.

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Large multimedia databases and digital image archival systems are being created in government, academia, military, hospitals, digital libraries, and businesses. Efficient methods to retrieve images from such large databases have become indispensable. In this chapter, the authors present a novel Wavelet Packet (WP)-based method for image identification and retrieval that enables the recovery of the original image from a database even if the image has been subjected to geometric transformations such as size-conserving rotation or flipping operations. The proposed method uses the correlation of wavelet packet coefficients to create an image signature. This signature is comprised of two parts. The first part is a short signature, SS, that represents the location of specific values of the WP coefficient correlations in each frequency band. The second portion is the basis signature of the image, which is a long signature, LS, of 1296 correlation points produced by summing up the correlation values along all frequency bands. Computer simulation results show that the method is extremely fast, has a perfect image retrieval rates (100%), and perfect geometric transformations recognition, if any. In addition, the simulation results show that target images are perfectly identified from an image database of 7500 image signatures within a short period of time (nearly 8 seconds on the average). This method is robust against geometric transformation and requires minimal data transfer and can be used for online image retrieval.
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Zouari, Farouk, and Amina Boubellouta. "Adaptive Neural Control for Unknown Nonlinear Time-Delay Fractional-Order Systems With Input Saturation." In Advanced Synchronization Control and Bifurcation of Chaotic Fractional-Order Systems, 54–98. IGI Global, 2018. http://dx.doi.org/10.4018/978-1-5225-5418-9.ch003.

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This chapter focuses on the adaptive neural control of a class of uncertain multi-input multi-output (MIMO) nonlinear time-delay non-integer order systems with unmeasured states, unknown control direction, and unknown asymmetric saturation actuator. The design of the controller follows a number of steps. Firstly, based on the semi-group property of fractional order derivative, the system is transformed into a normalized fractional order system by means of a state transformation in order to facilitate the control design. Then, a simple linear state observer is constructed to estimate the unmeasured states of the transformed system. A neural network is incorporated to approximate the unknown nonlinear functions while a Nussbaum function is used to deal with the unknown control direction. In addition, the strictly positive real (SPR) condition, the Razumikhin lemma, the frequency distributed model, and the Lyapunov method are utilized to derive the parameter adaptive laws and to perform the stability proof.
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Rohling, Hermann. "OFDM Transmission Technique." In Mobile Computing, 3561–87. IGI Global, 2009. http://dx.doi.org/10.4018/978-1-60566-054-7.ch260.

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The orthogonal frequency division multiplexing (OFDM) transmission technique can efficiently deal with multi-path propagation effects especially in broadband radio channels. It also has a high degree of system flexibility in multiple access schemes by combining the conventional TDMA; FDMA; and CDMA approaches with the OFDM modulation procedure; which is especially important in the uplink of a multi-user system. In OFDM-FDMA schemes carrier synchronization and the resulting sub-carrier orthogonality plays an important role to avoid any multiple access interferences (MAI) in the base station receiver. An additional technical challenge in system design is the required amplifier linearity to avoid any non-linear effects caused by a large peak-to-average ratio (PAR) of an OFDM signal. The OFDM transmission technique is used for the time being in some broadcast applications (DVB-T; DAB; DRM) and wireless local loop (WLL) standards (HIPERLAN/2; IEEE 802.11a) but OFDM has not been used so far in cellular communication networks. The general idea of the OFDM scheme is to split the total bandwidth into many narrowband sub-channels which are equidistantly distributed on the frequency axis. The sub-channel spectra overlap each other but the sub-carriers are still orthogonal in the receiver and can therefore be separated by a Fourier transformation. The system flexibility and use of sub-carrier specific adaptive modulation schemes in frequency selective radio channels are some advantages which make the OFDM transmission technique a strong and technically attractive candidate for the next generation of mobile communications. The objective of this chapter is to describe an OFDM-based system concept for the fourth generation (4G) of mobile communications and to discuss all technical details when establishing a cellular network which requires synchronization in time and frequency domain with sufficient accuracy. In this cellular environment a flexible frequency division multiple access scheme based on OFDM-FDMA is developed and a radio resource management (RRM) employing dynamic channel allocation (DCA) techniques is used. A purely decentralized and self-organized synchronization technique using specific test signals and RRM techniques based on co-channel interference (CCI) measurements has been developed and will be described in this chapter.
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Karabegović, Isak, Edina Karabegović, Mehmed Mahmic, and Ermin Husak. "The Implementation of Industry 4.0 by Using Industrial and Service Robots in the Production Processes." In Advances in Business Information Systems and Analytics, 1–30. IGI Global, 2020. http://dx.doi.org/10.4018/978-1-7998-2725-2.ch001.

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From the very knowledge of Industry 4.0, its implementation is carried out in all segments of society, but we still do not fully understand the breadth and speed of its implementation. We are currently witnessing major changes in all industries, so new business methods are emerging. There is a transformation of production systems, a new form of consumption, delivery, and transportation, all thanks to the implementation of new technological discoveries that cover robotics and automation, the internet of things (IoT), 3D printers, smart sensors, radio frequency identification (RFID), etc. Robotic technology is one of the most important technologies in Industry 4.0, so that the robot application in the automation of production processes with the support of information technology brings us to smart automation (i.e., smart factories). The changes are so deep that, from the perspective of human history, there has never been a time of greater promise or potential danger.
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Karabegović, Isak, Edina Karabegović, Mehmed Mahmic, and Ermin Husak. "The Implementation of Industry 4.0 by Using Industrial and Service Robots in the Production Processes." In Research Anthology on Cross-Industry Challenges of Industry 4.0, 656–85. IGI Global, 2021. http://dx.doi.org/10.4018/978-1-7998-8548-1.ch034.

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From the very knowledge of Industry 4.0, its implementation is carried out in all segments of society, but we still do not fully understand the breadth and speed of its implementation. We are currently witnessing major changes in all industries, so new business methods are emerging. There is a transformation of production systems, a new form of consumption, delivery, and transportation, all thanks to the implementation of new technological discoveries that cover robotics and automation, the internet of things (IoT), 3D printers, smart sensors, radio frequency identification (RFID), etc. Robotic technology is one of the most important technologies in Industry 4.0, so that the robot application in the automation of production processes with the support of information technology brings us to smart automation (i.e., smart factories). The changes are so deep that, from the perspective of human history, there has never been a time of greater promise or potential danger.
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Coller, Ian. "The Muslim Republic." In Muslims and Citizens, 125–47. Yale University Press, 2020. http://dx.doi.org/10.12987/yale/9780300243369.003.0008.

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This chapter traces the growing interconnection with the Ottoman Empire, and in particular the North African powers, who rejected pressures to join the coalition against France and became increasingly critical partners in economic, military, and diplomatic terms. Algiers at the time was in rapid transformation, a kind of “republic” analogous to France, adapting to the new geopolitical context. North Africans were crossing to France with greater frequency, so much so that the Algerians hoped to establish a passenger ferry between the two countries. As republican France articulated a new openness to Islam, Algeria began to view the republic as a friend and partner rather than a religious enemy. In France, older fears of the barbarian pirates were giving way to the new conceptions of Muslims, but could still exert considerable force. The dey of Algiers demonstrated particular support for the new French Republic, offering financial support that would never be repaid, and which would ultimately serve as a catalyst for the French invasion of Algeria four decades later.
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Conference papers on the topic "Frequency-to-time transformation"

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Bellan, Diego, and Sergio A. Pignari. "Noise influence in time-to-frequency transformation of radiated emissions data." In 2008 International Symposium on Electromagnetic Compatibility - EMC Europe. IEEE, 2008. http://dx.doi.org/10.1109/emceurope.2008.4786835.

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Zhou, Changfei, Jiahui Fu, Yuanming Guo, and Qun Wu. "Time and frequency domain transformation to the far field with FDTD." In 2012 5th Global Symposium on Millimeter Waves (GSMM 2012). IEEE, 2012. http://dx.doi.org/10.1109/gsmm.2012.6314003.

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Hayashi, Masahiro. "Transformation from Availability Expression to Time-Specific Failure/Success Frequency Expressions." In 2018 3rd International Conference on System Reliability and Safety (ICSRS). IEEE, 2018. http://dx.doi.org/10.1109/icsrs.2018.8688853.

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Preda, I., J. Castellon, S. Agnel, P. Notingher, M. Frechette, T. Heid, H. Couderc, N. Freebody, and A. S. Vaughan. "Conduction currents and time to frequency domain transformation for epoxy resin nanocomposites." In 2013 IEEE International Conference on Solid Dielectrics (ICSD). IEEE, 2013. http://dx.doi.org/10.1109/icsd.2013.6619711.

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Ahadi, Mojtaba, Ayaz Ghorbani, and Gholamreza Moradi. "Near zone to far zone transformation with mixed finite-difference time-domain and frequency-domain." In 2008 IEEE International RF and Microwave Conference (RFM). IEEE, 2008. http://dx.doi.org/10.1109/rfm.2008.4897417.

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Patil, Sunil, Laith Zori, Paul Galpin, JuanCarlos Morales, and Philippe Godin. "Investigation of Time/Frequency Domain CFD Methods to Predict Turbomachinery Blade Aerodynamic Damping." In ASME Turbo Expo 2016: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/gt2016-57962.

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Accurate and efficient prediction of blade aerodynamic damping is critical for the design of turbomachines such as gas and steam turbines. Traditional unsteady time-marching CFD methods used in aerodynamic damping calculations are expensive because they require simulation of many or all blade passages in a given blade-row. In order to reduce computational cost, one can use a pitch-change method and reduce the problem to a small sector of the geometry (one or two blades). Even still, the time-marching method is expensive as many vibration cycles must be simulated to reach a quasi-steady periodic state. To further reduce computational cost, a time/frequency solution method is required. This paper uses an implicit pressure-based time/frequency solution method in combination with a Fourier transformation (FT) pitch-change method and validates its implementation in ANSYS CFX solver. Three cases are investigated, including Standard Configuration 11 (subsonic and transonic), and NASA Rotor 67 transonic fan. Predictions of unsteady pressure coefficient are compared against the experimental data and reference full wheel simulations, over a range of nodal diameters. Computational resources (CPU time) required by the time/frequency method are compared to time transient simulations and discussed in detail.
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Wang, Xin, and C. Steve Suh. "Nonlinear Time-Frequency Control of Permanent Magnet Synchronous Motors." In ASME 2016 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/imece2016-67363.

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Permanent magnet synchronous motors are essential components in a wide range of applications in which their unique benefits are explored. However, in order for a permanent magnet synchronous motor to achieve satisfactory performance, particular control frameworks are essential. After all, permanent magnet synchronous motor is an AC machine, which is characterized by its complex structure and strongly coupled system states. Therefore, in order for it to achieve satisfactory dynamic performance, advanced control techniques are the only solution. This paper presents a precise speed control of permanent magnet synchronous motors using the nonlinear time-frequency control concept. The novel aspect of this nonlinear time-frequency control, which is an integration of discrete wavelet transformation and adaptive control, is its ability in analyzing the fundamental temporal and spectral qualities inherent of a permanent magnet synchronous motor and exerting control signals accordingly. Simulation results verifies that the proposed nonlinear time-frequency control scheme is feasible for alleviating the nonlinear behavior of the permanent magnet synchronous motor which hampers the tracking of speed with desired precision.
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Liu, Yalin, Shangguan Bo, and Zili Xu. "Improved Hybrid Frequency-Time Domain Method for Nonlinear Analysis of Frictionally Damped Blade Systems." In ASME Turbo Expo 2016: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/gt2016-56852.

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An improved hybrid frequency-time domain method is proposed to efficiently study the nonlinear response of blade systems subject to dry friction damping. In this method, the friction force is calculated in time domain by tracing the motion trajectory of friction contact pairs. The Newton iterative algorithm is used to solve the algebraic equations of blade system in frequency domain. The parabolic-interpolation fast Fourier transform is used in time-frequency domain transformation. It can improve computation accuracy and enlarge spectral analysis range of the original alternating frequency/time domain (AFT) method. The multi-modal analysis technique is employed to reduce linear degree of freedoms (DOFs), and only the nonlinear DOFs are brought in iterative procedure. It can significantly reduce computation time. The improved method combined with three dimensional friction contact model is used to predict the vibration response of a shrouded blade with nonlinear friction contact. The effect of parameters on resonant frequency and response is investigated and discussed. The computation time of the improved method is only 42.25 percent of the original AFT method, while the relative difference between the results of the two methods is no more than 0.01%. The improved method is shown to be superior to the original AFT method in computation efficiency and accuracy, and it can be used in analyzing dynamic characteristics of complex frictionally damped blade systems.
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Southern, Jacob D. "Nonlinear Time-Frequency Control of Electromagnetic Solenoid Valve." In ASME 2016 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/imece2016-67383.

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The main objective of this study is to prove that an electromagnetic solenoid valve can be controlled accurately and have a rapid response time while not having to linearize the system. An electromagnetic solenoid valve can neither be slow nor have large amounts of error due to the small distances between the pressure ports and the accuracy of the system they are used to control. The valve modeled for this study was an automotive transmission solenoid valve. The solenoid valve has three ports: supply, exhaust, and controlled pressure. For simplification, this model only considers moving the spool to a specific port location, which will be user specified. The controller used for this system was a nonlinear time-frequency controller that uses Daubechies-3 wavelets for signal transformation. Once, the controller was optimized it was able to control the system accurately and with a rapid response time. The system is able to reach the desired input and maintain zero error in two tenths of a second with out greatly over shooting the desired input. Overall, this system is physically possible to control the way the simulation predicts because all of the parameters used in the simulation are from a real solenoid valve.
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Li, Wei, Guang Dai, Ying Zhang, Feifei Long, and Yanru Wang. "Empirical Mode Decomposition of AE Signal Processing Based on Hilbert-Huang Transformation." In ASME 2009 Pressure Vessels and Piping Conference. ASMEDC, 2009. http://dx.doi.org/10.1115/pvp2009-77001.

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In this paper a new signal processing method of Hilbert-Huang transform is applied to analyze AE lead-breaking signals and loaded concrete AE signals. Empirical model of decomposition (EMD) and cubic interpolation were used in AE signals analysis which was based on the local characteristic time scale. After the decomposition inherent model function (IMF) can effectively preserve non-linear and non-stationary features of signals during the processing. Meanwhile, noises of signals were eliminated by using multi-dimension filter property of EMD. The above two signal’s IMF can be clearly shown on a time-frequency vs. energy distribution spectrum and marginal spectrum by Hilbert-Huang transformation. The results show that HHT can efficiently reflecting the intrinsic properties of signals. Besides, HHT method, which is more adaptive than other methods, had a bigger superiority in adaptability and frequency concentration, and it has batter localization property and visual result of the time-frequency domain.
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