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Journal articles on the topic "Spectrum"
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Zhang, Lian Shun, and Ai Juan Shi. "Classification of Biological Spectrum Based on Principal Component Cluster Analysis." Advanced Materials Research 605-607 (December 2012): 2245–48. http://dx.doi.org/10.4028/www.scientific.net/amr.605-607.2245.
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Spectrums of 17 biological tissue phantoms were measured using the fiber-optic spectrometer. Then, the spectrum was preprocessed by multiplicative scatter correction method to devoice the spectrum. Afterwards the features of the spectrum were extracted via principal component analysis. Ultimately, we applied cluster analysis for the spectral features. The results showed that the accumulated credibility of the first 12 spectral principal components was 99.86% for the spectrum after preprocessing; indicating that this spectrum feature extraction might be done in the case of losing no key information. And the results showed that the 17 biological tissue phantoms can be divided into four main categories according their optical features.
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Mück, Markus, and Christophe GAIE. "The Future of Spectrum Management - Conciliating Spectrum Allocation, Spectral Efficiency and Spectrum Monetization." International Journal of Computational Systems Engineering 7, no. 1 (2022): 1. http://dx.doi.org/10.1504/ijcsyse.2022.10054832.
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Gaie, Christophe, and Markus Mueck. "The future of spectrum management - conciliating spectrum allocation, spectral efficiency and spectrum monetisation." International Journal of Computational Systems Engineering 7, no. 1 (2022): 1. http://dx.doi.org/10.1504/ijcsyse.2022.131031.
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He, Wei, De Tian, and Wei Long Wang. "Effect of Wind Shear on Rotational Fourier Spectrum of Wind Turbine." Applied Mechanics and Materials 271-272 (December 2012): 872–76. http://dx.doi.org/10.4028/www.scientific.net/amm.271-272.872.
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In order to accurately obtain the influence of rotational effect on fluctuating component of turbulent wind acted on wind turbine, considering source spectrum and rotational sample points were changed since wind shear changed mean wind speed in the rotor plane along the vertical direction, rotational Fourier spectrum with wind shear was deduced. Based on the investigation on a 3MW three-bladed pitch regulated wind turbine, rotational Fourier spectrums with and without wind shear were compared, the effect of radius on rotational Fourier spectrum was analyzed, cross power spectral densities of rotational Fourier spectrum with different blades and variable radius were compared. The results show that the effect of wind shear on amplitude of rotational Fourier spectrum is unconspicuous while the phase frequency characteristic is alternative for the sample points are changed. Rotational Fourier spectrum energy removes to the high frequency bands, the amplitudes of peak at the integer multiple rotational frequencies increase with radius increases. The initial phase has little influence to the amplitude of spectrum, and cross power spectral densities of different radius are obviously less than auto power spectral densities of the same radius.
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Wang, Mingxun, and Nuno Bandeira. "Spectral Library Generating Function for Assessing Spectrum-Spectrum Match Significance." Journal of Proteome Research 12, no. 9 (July 31, 2013): 3944–51. http://dx.doi.org/10.1021/pr400230p.
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Yen, Chia-Yu, Stephane Houel, Natalie G. Ahn, and William M. Old. "Spectrum-to-Spectrum Searching Using a Proteome-wide Spectral Library." Molecular & Cellular Proteomics 10, no. 7 (April 30, 2011): M111.007666. http://dx.doi.org/10.1074/mcp.m111.007666.
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Et.al, Tae-Yun Jung. "Spectrum Sensing Based On Deep Learning To Increase Spectrum Utilization." Turkish Journal of Computer and Mathematics Education (TURCOMAT) 12, no. 6 (April 10, 2021): 538–43. http://dx.doi.org/10.17762/turcomat.v12i6.1971.
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This paper proposes a new spectrum sensing technique for cognitive radio systems. To determine vacancy of the spectrum, the proposed method employs the recurrent neural network (RNN), one of the popular deep learning techniques. The proposed technique determines the spectrum occupancy of the primary user (PU) by observing the received signal’s energy and any information on the PU signal characteristic is not used. To this end, the received signal’s spectrum is obtained by fast Fourier transform (FFT). This process is performed on consecutive received signals and the resulting spectrums are stacked. Finally, a 2-dimensional spectrum (or spectrogram) is made. This 2-D spectrum is cut into sensing channel bandwidths and inputted to the deep learning model to decide the channel’s occupancy. While the recently published spectrum sensing technique based on convolutional neural network (CNN) relies on an empty channel, the proposed technique does not require any empty channel. Only the channel signal of interest to sense is needed. Since spectrum sensing results is two (busy or idle), binary classification deep learning model is developed. According to the computer simulation results, the proposed method has similar performance with the conventional CNN-based method while the spectral efficiency of the proposed method is much higher than that of the existing scheme. In addition, the overall learnable parameters of the proposed deep learning model is only 2/3 of the existing method
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Wang, Gao, Jian Quan Yao, De Gang Xu, Gao Wang, and Xiao Fang Ren. "Research on Three Fierce Exploders Reflected Terahertz Spectrum." Advanced Materials Research 760-762 (September 2013): 492–96. http://dx.doi.org/10.4028/www.scientific.net/amr.760-762.492.
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The rapid development of the Terahertz technology has been the essential focus among all application fields. In order to applying the spectral technology to the security and analyzing all exploders spectrum characteristics, the paper aims to three exploders spectrums researches including the HNS, DNMT and DNAN. The three reflected spectrums are tested and analyzed, using the most advanced portable terahertz spectrometer, and the absorption peaks among 0.1~2.5THz are determined successfully.
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Muraleedharan, Thettath K., and Krishnan Parthasarathy. "Difference spectrum and spectral synthesis." Tohoku Mathematical Journal 51, no. 1 (1999): 65–73. http://dx.doi.org/10.2748/tmj/1178224853.
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Cokelaer, Thomas, and Juergen Hasch. "'Spectrum': Spectral Analysis in Python." Journal of Open Source Software 2, no. 18 (October 27, 2017): 348. http://dx.doi.org/10.21105/joss.00348.
Full textDissertations / Theses on the topic "Spectrum"
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Lee, Haeyoung. "Dynamic spectrum sharing by opportunistic spectrum access with spectrum aggregation." Thesis, University of Surrey, 2015. http://epubs.surrey.ac.uk/807078/.
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The rapid growth of wireless services and the breakneck proliferation of wireless devices continue to strain limited spectrum resource. While the need for efficient spectrum sharing mechanisms has been emphasized, opportunistic spectrum access has been considered as a promising mechanism for dynamic spectrum sharing. However, although the idle spectrum could exist, it is usually rather fragmented and distributed, and hence the secondary network users would face the difficulty in finding required contiguous spectrum. Spectrum aggregation can be exploited to provide effective wide bandwidth communication but at the cost of complexity and overhead. When a primary network uses spectrum dynamically, from the nature of opportunistic spectrum access, collisions can occur between primary and secondary transmissions and spectrum handoff can be utilised to provide reliable communication. However, collision occurrence results in spectrum handoff delay in a secondary network user (SU) along with short-term interference to a primary network user (PU). As a SU accesses more spectrum for higher data rates by spectrum aggregation, collisions can occur more frequently and frequent spectrum handoff will be required. While spectrum aggregation will allow the SU to have high flexibility in spectrum use and spectrum handoff can help improve the reliability of secondary transmissions, the SU faces a new spectrum allocation problem: How wide and which parts of spectrum opportunities should be aggregated while considering the complexity and the overhead for aggregation and for spectrum handoff? This thesis addresses the key challenge of opportunistic spectrum access, focusing on efficient spectrum sharing considering the fragmentation of spectrum opportunities in frequency and time domains. First, considering complexity and overhead for aggregation, the spectrum aggregation approach is investigated and guidelines are derived how to reduce spectrum fragmentation for the efficient spectrum utilisation based on simulation results. Second, the relationship between collision occurrence and spectrum aggregation is analysed. Collision probabilities between primary and secondary transmissions are derived and the impacts of spectrum aggregation on data rates and spectrum handoff are investigated. Then, a spectrum aggregation algorithm is proposed to maximise data rates for a given collision probability threshold. Third, when considering spectrum handoff, the impacts of spectrum aggregation on spectrum handoff and short-term interference to PUs are analysed. Then, the spectrum aggregation algorithm is designed with the aim to minimise collision. Finally, the results of this study are summarised, conclusions are presented and a number of future research topics are proposed.
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Dahl, Jason F. "Time Aliasing Methods of Spectrum Estimation." Diss., CLICK HERE for online access, 2003. http://contentdm.lib.byu.edu/ETD/image/etd157.pdf.
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Lu, Lu. "Spectral-efficient design in modern wireless communications networks." Diss., Georgia Institute of Technology, 2015. http://hdl.handle.net/1853/53902.
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We investigate spectral-efficient design and develop novel schemes to improve spectral efficiency of the modern wireless communications networks. Nowadays, more and more spectrum resources are required to support various high-data-rate applications while spectrum resources are limited. Moreover, static allocation and exclusive access in current spectrum assignment policy caused a lot of licensed spectrum bands to be underutilized. To deal with the problem, cognitive radio (CR) has been developed, which allows unlicensed/secondary users to transmit with licensed/primary users as long as the former ones do not generate intolerable interference to the latter ones. The coexistence of users and networks requires careful and dynamic planning to mitigate interference. Otherwise, the network performance will be severely undermined. We study both spectrum sensing and spectrum access techniques and propose several transmit schemes for different types of cognitive ratio networks, including spectrum overlay and spectrum underlay systems. The proposed algorithms can improve spectral efficiency of the networks efficiently and have potentials to be used in future wireless communications networks.
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Bhattarai, Sudeep. "Spectrum Efficiency and Security in Dynamic Spectrum Sharing." Diss., Virginia Tech, 2018. http://hdl.handle.net/10919/82872.
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We are in the midst of a major paradigm shift in how we manage the radio spectrum. This paradigm shift in spectrum management from exclusive access to shared access is necessitated by the growth of wireless services and the demand pressure imposed on limited spectrum resources under legacy management regimes. The primary constraint in any spectrum sharing regime is that the incumbent users (IUs) of the spectrum need to be protected from harmful interference caused due to transmissions from secondary users (SUs). Unfortunately, legacy techniques rely on inadequately flexible and overly conservative methods for prescribing interference protection that result in inefficient utilization of the shared spectrum.
In this dissertation, we first propose an analytical approach for characterizing the aggregate interference experienced by the IU when it shares the spectrum with multiple SUs. Proper characterization of aggregate interference helps in defining incumbent protection boundaries, a.k.a. Exclusion Zones (EZs), that are neither overly aggressive to endanger the IU protection requirement, nor overly conservative to limit spectrum utilization efficiency. In particular, our proposed approach addresses the two main limitations of existing methods that use terrain based propagation models for estimating the aggregate interference. First, terrain-based propagation models are computationally intensive and data-hungry making them unsuitable for large real-time spectrum sharing applications such as the spectrum access system (SAS). Second, terrain based propagation models require accurate geo-locations of SUs which might not always be available, such as when SUs are mobile, or when their locations are obfuscated for location privacy concerns.
Our second contribution in this dissertation is the novel concept of Multi-tiered Incumbent Protection Zones (MIPZ) that can be used to prescribe interference protection to the IUs. Based on the aforementioned analytical tool for characterizing the aggregate interference, we facilitate a framework that can be used to replace the legacy notion of static and overly conservative EZs with multi-tiered dynamic EZs. MIPZ is fundamentally different from legacy EZs in that it dynamically adjusts the IU's protection boundary based on the radio environment, network dynamics, and the IU interference protection requirement. Our extensive simulation results show that MIPZ can be used to improve the overall spectrum utilization while ensuring sufficient protection to the IUs.
As our third contribution, we investigate the operational security (OPSEC) issue raised by the emergence of new spectrum access technologies and spectrum utilization paradigms. For instance, although the use of geolocation databases (GDB) is a practical approach for enabling efficient spectrum sharing, it raises a potentially serious OPSEC problem, especially when some of the IUs are federal government entities, including military users. We show that malicious queriers can readily infer the locations of the IUs even if the database's responses to the queries do not directly reveal such information. To address this issue, we propose a perturbation-based optimal obfuscation strategy that can be implemented by the GDB to preserve the location privacy of IUs. The proposed obfuscation strategy is optimal in the sense that it maximizes IUs' location privacy while ensuring that the expected degradation in the SUs' performance due to obfuscated responses does not exceed a threshold.
In summary, this dissertation focuses on investigating techniques that improve the utilization efficiency of the shared spectrum while ensuring adequate protection to the IUs from SU induced interference as well as from potential OPSEC threats. We believe that this study facilitates the regulators and other stakeholders a better understanding of mechanisms that enable improved spectrum utilization efficiency and minimize the associated OPSEC threats, and hence, helps in wider adoption of dynamic spectrum sharing.Ph. D.
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Valieva, Inna. "Spectrum Sensing for Dynamic Spectrum Access in Cognitive Radio." Licentiate thesis, Mälardalens högskola, Akademin för innovation, design och teknik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-52881.
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Abstract. The number of mobile devices is constantly growing, and the exclusivestatic spectrum allocation approach is leading to the spectrum scarcity problem whensome of the licensed bands are heavily occupied and others are nearly unused.Spectrum sharing and opportunistic spectrum access allow achieving more efficientspectrum utilization. Radio scene analysis is a first step in the cognitive radiooperation required to employ opportunistic spectrum access scenarios such as thedynamic spectrum access or frequency hopping spread spectrum. The objective of thiswork is to develop and virtual prototype the subset of radio scene analysis algorithmsintended to be used for deployment of opportunistic spectrum access in our targetapplication: a cognitive radio network consisting of multiple software-defined radionodes BitSDR. The proposed radio scene analysis algorithms are devoted to solvingtwo radio scene analysis problems: 1. detection of vacant frequency channels toimplement spectrum sharing scenarios; 2. waveform estimation including modulationtype, symbol rate, and central frequency estimation. From the subset of two radioscene analysis problems two hypotheses are formulated: the first is related to thevacant band identification and the second to waveform estimation. Then sevenresearch questions related to the trade-off between the sensing accuracy and real-time operation requirement for the proposed radio scene analysis algorithms, the nature of the noise, and assumptions used to model the radio scene environment such as the AWGN channel. In the scope of this work, Hypothesis 1, dedicated to vacant frequency band detection, has been proven. Research questions related to the selection of the observation bandwidth, vacant channels detection threshold, and the optimal algorithm have been answered. We have proposed, prototyped, and tested a vacant frequency channels detection algorithm based on wavelet transform performing multichannel detection in the wide band of 56 MHz based on the received signal observed during500 microseconds. Detection accuracy of 91 % has been demonstrated. Detection has been modeled as a binary hypothesis testing problem. Also, energy detection and cyclostationary feature extraction algorithms have been prototyped and tested, however, they have shown lower classification accuracy than wavelets. Answering research question 7 revealed the advantage of using wavelets due to the potential of the results of wavelet transform to be applied for solving the waveform estimation problem including symbol rate and modulation type. Test data samples have been generated during the controlled experiment by the hardware signal generator and received by proprietary hardware based on AD9364 Analog Devices transceiver. To test Hypothesis 2 research questions related to the waveform estimation have been elaborated. We could not fully prove Hypothesis 2 in the scope of this work. The algorithm and features that have been chosen for modulation type classification have not met the required classification accuracy to classify between five studied modulation classes 2FSK, BPSK, QPSK, 8PSK, and 16PSK. To capture more of the fine differences between the received signal modulated into different linear modulations it has been suggested to use the spectral features derived from the time-series signal observed during 500 microseconds or less observation time in the scope of the future work. However, the binary classification between 2FSK and BPSKpresented in Paper 1 could be performed based on instantaneous values and SNRinput: ensemble boosted trees and decision trees have shown an average classification accuracy of 86.3 % and 86.0 % respectively and classification speed of 1200000objects per second, what is faster than required 2000 objects per second.3The prototyping and testing of the proposed algorithm for symbol rate estimation based on deep learning have been performed to answer research question 2. Wavelet transform feature extraction has been proposed to be applied as a preprocessing step for deep learning-based estimation of the symbol rate for 2FSK modulated signals. This algorithm has shown an improvement in the accuracy of the symbol rate estimation in comparison with cyclostationary based detection. The validation accuracy of the symbol rate classification has reached 99.7 %. During testing, the highest average classification accuracy of 100 % has been observed for the signals with SNR levels 25-30 dB, while for signals with SNR 20-25 dB it was 96.3 %.
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Deepak, G. C. "Spectrum sharing systems for improving spectral efficiency in cognitive cellular network." Thesis, Lancaster University, 2017. http://eprints.lancs.ac.uk/85771/.
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Since spectrum is the invisible infrastructure that powers the wireless communication, the demand has been exceptionally increasing in recent years after the implementation of 4G and immense data requirements of 5G due to the applications, such as Internet-of-Things (IoT). Therefore, the effective optimization of the use of spectrum is immediately needed than ever before. The spectrum sensing is the prerequisite for optimal resource allocation in cognitive radio networks (CRN). Therefore, the spectrum sensing in wireless system with lower latency requirements is proposed first. In such systems with high spatial density of the base stations and users/objects, spectrum sharing enables spectrum reuse across very small regions. The proposed method in this Thesis is a multi-channel cooperative spectrum sensing technique, in which an independent network of sensors, namely, spectrum monitoring network, detects the spectrum availability. The locally aggregated decision in each zone associated with the zone aggregator (ZA) location is then passed to a decision fusion centre (DFC). The secondary base station (SBS) accordingly allocates the available channels to secondary users to maximize the spectral efficiency. The function of the DFC is formulated as an optimization problem with the objective of maximizing the spectral efficiency. The optimal detection threshold is obtained for different cases with various spatial densities of ZAs and SBSs. It is further shown that the proposed method reduces the spectrum sensing latency and results in a higher spectrum efficiency. Furthermore, a novel power allocation scheme for multicell CRN is proposed where the subchannel power allocation is performed by incorporating network-wide primary system communication activity. A collaborative subchannel monitoring scheme is proposed to evaluate the aggregated subchannel activity index (ASAI) to indicate the activity levels of primary users. Two utility functions are then defined to characterize the spectral efficiency (SE) and energy efficiency (EE) as a function of ASAI to formulate a utility maximization problem. The optimal transmit power allocation is then obtained with the objective of maximizing the total utility at the SBS, subject to maximum SBS transmit power and collision probability constraint at the primary receivers. Since optimal EE and SE are two contradicting objectives to obtain the transmit power allocation, the design approach to handle both EE and SE as a function of common network parameter, i.e., ASAI, is provided which ultimately proves the quantitative insights on efficient system design. Extensive simulation results confirm the analytical results and indicate a significant improvement in sensing latency and accuracy and a significant gain against the benchmark models on the rate performance, despite the proposed methods perform with lower signalling overhead.
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Brahma, Swastik Kumar. "Spectrum sharing and service pricing in dynamic spectrum access networks." Doctoral diss., University of Central Florida, 2011. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/4854.
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Traditionally, radio spectrum has been statically allocated to wireless service providers (WSPs). Regulators, like FCC, give wireless service providers exclusive long term licenses for using specific range of frequencies in particular geographic areas. Moreover, restrictions are imposed on the technologies to be used and the services to be provided. The lack of flexibility in static spectrum allocation constrains the ability to make use of new technologies and the ability to redeploy the spectrum to higher valued uses, thereby resulting in inefficient spectrum utilization (23, 38, 42, 62, 67). These limitations have motivated a paradigm shift from static spectrum allocation towards a more 'liberalized' notion of spectrum management in which secondary users can borrow idle spectrum from primary spectrum licensees, without causing harmful interference to the latter- a notion commonly referred to as dynamic spectrum access (DSA) or open spectrum access (3), (82). Cognitive radio (30, 47), empowered by Software Defined Radio (SDR) (81), is poised to promote the efficient use of spectrum by adopting this open spectrum approach. In this dissertation, we first address the problem of dynamic channel (spectrum) access by a set of cognitive radio enabled nodes, where each node acting in a selfish manner tries to access and use as many channels as possible, subject to the interference constraints. We model the dynamic channel access problem as a modified Rubinstein-Stahl bargaining game. In our model, each node negotiates with the other nodes to obtain an agreeable sharing rule of the available channels, such that, no two interfering nodes use the same channel. We solve the bargaining game by finding Subgame Perfect Nash Equilibrium (SPNE) strategies of the nodes. First, we consider finite horizon version of the bargaining game and investigate its SPNE strategies that allow each node to maximize its utility against the other nodes (opponents).; We then extend these results to the infinite horizon bargaining game. Furthermore, we identify Pareto optimal equilibria of the game for improving spectrum utilization. The bargaining solution ensures that no node is starved of channels. The spectrum that a secondary node acquires comes to it at a cost. Thus it becomes important to study the 'end system' perspective of such a cost, by focusing on its implications. Specifically, we consider the problem of incentivizing nodes to provide the service of routing using the acquired spectrum. In this problem, each secondary node having a certain capacity incurs a cost for routing traffic through it. Secondary nodes will not have an incentive to relay traffic unless they are compensated for the costs they incur in forwarding traffic. We propose a path auction scheme in which each secondary node announces its cost and capacity to the routing mechanism, both of which are considered as private information known only to the node. We design a route selection mechanism and a pricing function that can induce nodes to reveal their cost and capacity honestly (making our auction truthful), while minimizing the payment that needs to be given to the nodes (making our auction optimal). By considering capacity constraint of the nodes, we explicitly support multiple path routing. For deploying our path auction based routing mechanism in DSA networks, we provide polynomial time algorithms to find the optimal route over which traffic should be routed and to compute the payment that each node should receive. All our proposed algorithms have been evaluated via extensive simulation experiments. These results help to validate our design philosophy and also illustrate the effectiveness of our solution approach.ID: 030422691; System requirements: World Wide Web browser and PDF reader.; Mode of access: World Wide Web.; Thesis (Ph.D.)--University of Central Florida, 2011.; Includes bibliographical references (p. 161-166).
Ph.D.
Doctorate
Electrical Engineering and Computer Science
Engineering and Computer Science
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Ullah, Abid. "Mechanisms for Enhancing Spectrum Utilization in a Spectrum Access System." Diss., Virginia Tech, 2017. http://hdl.handle.net/10919/84932.
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The goal of this thesis is to build a Protected Shared Access Model (PSAM) through database enabled Spectrum Access System (SAS). A model for the SAS is proposed, which is based on our vision for the SAS as a more dynamic and responsive architecture as a geolocation database than the current TVWS database. Major functions and capabilities of the model include, calculations of exclusion zone (EZ) of primary users with different operational parameters, use interference estimation techniques for predicting interference levels
that will be generated by the new secondary users (SUs) and existing systems operating in the database service area, allocate location based transmit power levels and provide an algorithm for communications among the PUs, SUs, and the SAS to implement management and authorization framework of spectrum resources to different types of SUs.
The selection of a propagation model is of utmost importance in spectrum sharing studies. Existing literature on EZs with simplified propagation models does not consider the effect of LOS interference between the PU to SU link and SU to PU link on peak points in the terrain area around the PU. The use of a terrain profile based model captures the essence of propagation over irregular terrain. Terrain regions that are far away from the PU may have a LOS between the PU and SU. So its not only the nearest area where the PU/SU can get interference, but interference is present from areas further away on high grounds having a direct LOS with the PU antenna. The exclusion zone computation with terrain profile based propagation model captures this effect, and it is the same effect that makes the shape of the exclusion zone irregular. So the propagation model used in spectrum sharing studies must be able to use the terrain for the specific geographical area for precise propagation calculations, and provide statistical reliability parameters for the computed propagation values for area of interest.
For a multi-tier shared access model with incumbent access (IA) users, priority access (PA) users and general authorized access (GAA) users. The SU interference tolerance thresholds varies by the type of SU's i-e., PA users like public safety systems and mission critical users have low tolerance for interference and hence need to operate further from the PU. While GAA users like commercial broadband systems have higher interference tolerances and can operate closer to the PU. This multi-tier shared access model requires varying levels of interference protection from PU, that can be provided with multiple exclusion zones defined for different types of SU's.
We propose the concept of differential spectrum access hierarchy, and define it in the context of a multi-tiered EZs that are based on quantiles of tolerable interference levels for different tiers of SUs. We also quantify and show the gain in SU capacity (or throughput) obtained by using multi-tiered EZs for different tiers of SUs. Using simulation results, we show that the size of EZs can be significantly reduced with the use of a terrain profile-based propagation model that takes into account terrain profile for signal attenuation between PUs and SUs in the P2P link.
The exclusion zones involve the use of interference test points at the circumference of the protection contour of the PU. They are monitoring test points that the SAS uses with a propagation model and locations of SUs to calculate interference. Consider a model of Figure 5.1, the coexistence environment with PU, SU and the SAS with a database. As more SUs enter the system, their transmit powers creates interference for the PUs. In the event of SU interference exceeding a predefined threshold level at any of the test points, the SAS uses an interference based power control algorithm to turnoff the nearest dominant interferer's. Turning off the dominant interferers eliminates interference generated by that node at the PU. This nearest node interference cancellation significantly reduces the outage probability at the PU.
Unlike existing metrics for spectrum utilization efficiency that considers separate metrics for PU interference protection and maximum use of the band for secondary use, we define a new metric for spectrum utilization efficiency. This metric uses utility functions and cost functions to measure the impact of secondary use of the spectrum on PUs as well as the degree of satisfaction SUs can achieve from reuse of such spectrum. The new spectrum utilization metric is used to evaluate tradeoffs between interference protection of PUs and SU spectrum utilization.Ph. D.
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Lin, Yousi. "Spectrum Management Issues in Centralized and Distributed Dynamic Spectrum Access." Diss., Virginia Tech, 2021. http://hdl.handle.net/10919/104362.
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Dynamic spectrum access (DSA) is a powerful approach to mitigate the spectrum scarcity problem caused by rapid increase in wireless communication demands. Based on architecture design, DSA systems can be categorized as centralized and distributed. To successfully enable DSA, both centralized and distributed systems have to deal with spectrum management issues including spectrum sensing, spectrum decision, spectrum sharing and spectrum mobility. Our work starts by investigating the challenges of efficient spectrum monitoring in centralized spectrum sensing. Since central controllers usually require the presence information of incumbent users/primary users (IUs) for decision making, which is obtained during spectrum sensing, privacy issues of IUs become big concerns in some DSA systems where IUs have strong operation security needs. To aid in this, we design novel location privacy protection schemes for IUs. Considering the general drawbacks of centralized systems including high computational overhead for central controllers, single point failure and IU privacy issues, in many scenarios, a distributed DSA system is required. In this dissertation, we also cope with the spectrum sharing issues in distributed spectrum management, specifically the secondary user (SU) power control problem, by developing distributed and secure transmit power control algorithms for SUs.
In centralized spectrum management, the common approach for spectrum monitoring is to build infrastructures (e.g. spectrum observatories), which cost much money and manpower yet have relatively low coverage. To aid in this, we propose a crowdsourcing based spectrum monitoring system to capture the accurate spectrum utilization at a large geographical area, which leverages the power of masses of portable mobile devices. The central controller can accurately predict future spectrum utilization and intelligently schedule the spectrum monitoring tasks among mobile SUs accordingly, so that the energy of mobile devices can be saved and more spectrum activities can be monitored. We also demonstrate our system's ability to capture not only the existing spectrum access patterns but also the unknown patterns where no historical spectrum information exists. The experiment shows that our spectrum monitoring system can obtain a high spectrum monitoring coverage with low energy consumption.
Environmental Sensing Capability (ESC) systems are utilized in DSA in 3.5 GHz to sense the IU activities for protecting them from SUs' interference. However, IU location information is often highly sensitive in this band and hence it is preferable to hide its true location under the detection of ESCs. As a remedy, we design novel schemes to preserve both static and moving IU's location information by adjusting IU's radiation pattern and transmit power. We first formulate IU privacy protection problems for static IU. Due to the intractable nature of this problem, we propose a heuristic approach based on sampling. We also formulate the privacy protection problem for moving IUs, in which two cases are analyzed: (1) protect IU's moving traces; (2) protect its real-time current location information. Our analysis provides insightful advice for IU to preserve its location privacy against ESCs. Simulation results show that our approach provides great protection for IU's location privacy.
Centralized DSA spectrum management systems has to bear several fundamental issues, such as the heavy computational overhead for central controllers, single point failure and privacy concerns of IU caused by large amounts of information exchange between users and controllers and often untrusted operators of the central controllers. In this dissertation, we propose an alternative distributed and privacy-preserving spectrum sharing design for DSA, which relies on distributed SU power control and security mechanisms to overcome the limitations of centralized DSA spectrum management.Doctor of Philosophy
Due to the rapid growth in wireless communication demands, the frequency spectrum is becoming increasingly crowded. Traditional spectrum allocation policy gives the unshared access of fixed bands to the licensed users, and there is little unlicensed spectrum left now to allocate to newly emerged communication demands. However, studies on spectrum occupancy show that many licensed users who own the license of certain bands are only active for a small percentage of time, which results in plenty of underutilized spectrum. Hence, a new spectrum sharing paradigm, called dynamic spectrum access (DSA), is proposed to mitigate this problem. DSA enables the spectrum sharing between different classes of users, generally, the unlicensed users in the DSA system can access the licensed spectrum opportunistically without interfering with the licensed users. Based on architecture design, DSA systems can be categorized as centralized and distributed. In centralized systems, a central controller will make decisions on spectrum usage for all unlicensed users. Whereas in distributed systems, unlicensed users can make decisions for themselves independently. To successfully enable DSA, both centralized and distributed DSA systems need to deal with spectrum management issues, such as resource allocation problems and user privacy issues, etc. The resource allocation problems include, for example, the problems to discover and allocate idle bands and the problems to control users' transmit power for successful coexistence. Privacy issues may also arise during the spectrum management process since certain information exchange is inevitable for global decision making. However, due to the Federal Communications Commission's (FCC) regulation, licensed users' privacy such as their location information must be protected in any case. As a result, dynamic and efficient spectrum management techniques are necessary for DSA users. In this dissertation, we investigate the above-mentioned spectrum management issues in both types of DSA systems, specifically, the spectrum sensing challenges with licensed user location privacy issues in centralized DSA, and the spectrum sharing problems in distributed DSA systems. In doing so, we propose novel schemes for solving each related spectrum management problem and demonstrate their efficacy through the results from extensive evaluations and simulations. We believe that this dissertation provides insightful advice for DSA users to solve different spectrum management issues for enabling DSA implementation, and hence helps in a wider adoption of dynamic spectrum sharing.
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Stitz, Elizabeth H. "Instantaneous Power Spectrum." Thesis, Monterey, California : Naval Postgraduate School, 1990. http://handle.dtic.mil/100.2/ADA229098.
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Thesis (M.S. in Electrical Engineering)--Naval Postgraduate School, March 1990.Thesis Advisor(s): Hippenstiel, Ralph D. Second Reader: Cristi, Roberto. "March 1990." Description based on signature page as viewed on August 25, 2009. DTIC Identifier(s): Signal analysis, Time varying spectra, Wigner Ville distribution functions, Rihaczek distribution functions. Author(s) subject terms: Instantaneous Power Spectrum, spectral estimation, nonstationary signal analysis. Includes bibliographical references (p. 108-112). Also available online.
Books on the topic "Spectrum"
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Tomasi, Richard A. A spectrum of spectral problems. Tulsa, Oklahoma: Sunbelt R & T, Inc. [distributor], 1994.
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Tomasi, Richard A. A spectrum of spectral problems. Tulsa, Oklahoma: Sunbelt R & T, Inc., 1994.
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Kalisky, I. Spectrum &. Barnet: Glentop, 1985.
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Maurice, Clogan Paul, ed. Spectrum. Lanham, Md: Rowman & Littlefield, 1992.
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Spectra of Spectrum. Sunbelt R & T, 1992.
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Tomasi, R. A. Spectrum of Spectral Problems. Sunbelt R & T, 1994.
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Kirkby, Dave. Spectrum Maths (Spectrum Mathematics). Collins Educational, 1989.
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Kirkby, Dave. Spectrum Maths (Spectrum Mathematics). Collins Educational, 1989.
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Kirkby, Dave. Spectrum Maths (Spectrum Mathematics). Collins Educational, 1989.
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Kirkby, Dave. Spectrum Maths (Spectrum Mathematics). Collins Educational, 1989.
Find full textBook chapters on the topic "Spectrum"
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Sjöstrand, Johannes. "Spectrum and Pseudo-Spectrum." In Non-Self-Adjoint Differential Operators, Spectral Asymptotics and Random Perturbations, 9–28. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-10819-9_2.
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Gooch, Jan W. "Spectrum." In Encyclopedic Dictionary of Polymers, 687. New York, NY: Springer New York, 2011. http://dx.doi.org/10.1007/978-1-4419-6247-8_10982.
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Borre, Kai. "Spectrum." In Plane Networks and their Applications, 127–38. Boston, MA: Birkhäuser Boston, 2001. http://dx.doi.org/10.1007/978-1-4612-0165-6_5.
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Weik, Martin H. "spectrum." In Computer Science and Communications Dictionary, 1634. Boston, MA: Springer US, 2000. http://dx.doi.org/10.1007/1-4020-0613-6_17897.
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Kubrusly, Carlos S. "Spectrum." In Spectral Theory of Operators on Hilbert Spaces, 27–53. Boston: Birkhäuser Boston, 2012. http://dx.doi.org/10.1007/978-0-8176-8328-3_2.
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Cheverry, Christophe, and Nicolas Raymond. "SPECTRUM." In A Guide to Spectral Theory, 65–84. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-67462-5_3.
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Dranidis, Dimitris, and Stefan Gastinger. "Spectrum." In Lecture Notes in Computer Science, 199–228. Berlin, Heidelberg: Springer Berlin Heidelberg, 1995. http://dx.doi.org/10.1007/3-540-58867-1_56.
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Mortad, Mohammed Hichem. "Spectrum." In Counterexamples in Operator Theory, 121–43. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-97814-3_8.
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Mortad, Mohammed Hichem. "Spectrum." In Counterexamples in Operator Theory, 519–37. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-97814-3_29.
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Moro, José Luis. "Spectrum." In Building-Construction Design - From Principle to Detail, 741–70. Berlin, Heidelberg: Springer Berlin Heidelberg, 2024. http://dx.doi.org/10.1007/978-3-662-61742-7_25.
Full textConference papers on the topic "Spectrum"
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Lucchini, Andrea, Paolo Franchin, and Fabrizio Mollaioli. "A Spectrum-to-Spectrum Method for Calculating Uniform Hazard Floor Response Spectra." In ASME 2017 Pressure Vessels and Piping Conference. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/pvp2017-65293.
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In codes’ provisions and design procedures for acceleration-sensitive nonstructural components, seismic demand is commonly defined by means of floor response spectra expressed in terms of pseudo-acceleration. Depending on the considered analysis method, floor response spectra may be derived from floors’ acceleration histories, based on structural response-history analysis, or calculated using a predictive equation from a given input ground motion spectrum. Methods for estimating floor response spectra that are based on the second alternative are commonly called spectrum-to-spectrum methods. The objective of this paper is to briefly review these methods, and to discuss the main assumptions they are based on. Both predictive equations from selected seismic codes and proposals from the literature are included in the review. A new probability-based method, recently developed by the Authors for generating uniform hazard floor response spectra, namely, floor response spectra whose ordinates are characterized by a given target value of the mean annual frequency of being exceeded, is also described. By using this method floor spectra are determined through closed-form equations, given the mean annual frequency of interest, the damping ratio of the spectra, the modal properties of the structure, and three uniform hazard ground spectra. The method is built on a proposal for a probabilistic seismic demand model that relates the ground spectral acceleration with the floor spectral acceleration, and is able to explicitly account for the ground motion variability of the nonstructural response. Results for a case study consisting of a service frame of a visbreaking unit in an oil refinery are presented to show the good predictive accuracy of the method with respect to exact uniform hazard floor response spectra obtained through a standard probabilistic analysis.
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Azimirad, M., A. R. M. Gharabaghi, and M. R. Chenaghlou. "Deterministic-Spectral Fatigue Analysis of a Typical Jacket Platform (SPD1) Using Directional Wave Spectrum." In ASME 2007 26th International Conference on Offshore Mechanics and Arctic Engineering. ASMEDC, 2007. http://dx.doi.org/10.1115/omae2007-29418.
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Fixed offshore platforms or Jacket type platforms are the most common offshore structures used for oil & gas Exploration & Production industry in Persian Gulf, because water depth is such that the shallow water condition is dominant. Sea waves as dominant environmental loading are cyclic and have random nature. The applied cyclic sea wave forces will lead to fatigue damages in jacket’s joints. There are different methods to investigate the fatigue life of jackets such as deterministic method, simplified method, spectral method and transient method. Spectral method is a suitable method, which can consider the random nature of sea waves in fatigue analysis. Deterministic-spectral method developed by Bishop et al. is used to estimate the fatigue life of shallow water jacket platforms. However, in this method the frequency spectrum of waves is used in the analysis, but generally sea waves are propagating in different directions with different frequencies, so directional wave spectrum can consider wave randomness more properly. In this paper, frequency domain spectral method using Deterministic-Spectral approach has been used to estimate the fatigue life of a typical jacket platform (SPD1 at South Pars Field - Persian Gulf). Base wave cases were chosen from joint histogram of height & period that is calculated based on scatter diagrams of South Pars Field. First the jacket was modeled by ANSYS software, then by applying base wave cases to it and analyzing the critical TT joint under internal cyclic forces, hot spot stress transfer functions at 8 nodes around the intersection of joint were obtained. Using JONSWAP standard spectrum and the spreading function proposed by Goda, sea state’s Power Spectral Densities (PSD) and directional spectrums are multiplied to obtain stress spectra. The fatigue damage and fatigue life then are calculated. Results indicate that the fatigue life based on frequency spectrum is less than the fatigue life based on directional spectrum.
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Parkin, D. A., M. Clements, J. R. Holloway, C. Jackson, T. Jurand, and A. Van Den Berg. "Radar spectrum occupancy study (SPECTROC)." In 2004 International Waveform Diversity & Design Conference. IEEE, 2004. http://dx.doi.org/10.1109/iwddc.2004.8317559.
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Riza, Nabeel A., and Demetri Psaltis. "Optical disk based acousto-optic spectrum analysis." In OSA Annual Meeting. Washington, D.C.: Optica Publishing Group, 1990. http://dx.doi.org/10.1364/oam.1990.tuk5.
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This paper introduces optical disks in acousto-optic spectrum analyzers. In 2-D time and space integrating acousto-optic folded spectrum analyzers, electronic reference signals are used in the temporal spectral processing. In order to obtain complete folded spectrums, these reference signals have to be of extremely high timebandwidth product, and require extremely fast serial readout rates. It is difficult to generate these signals using electronics, and so far, only incomplete folded spectrums have been obtained. We address the signal generation problem by combining the angular motion, high storage capacity, and parallel access capability of optical disks. The disk is introduced as an optical distributed local oscillator generator and a light sampling 1-D spatial light modulator. The distributed local oscillator architecture forms the basis of a continuous wave 1-D time integrating spectrum analyzer. The reference signals are stored as concentric channels on the disk surface. When the disk spins with a constant angular velocity, each circular channel acts as a modulating light source with a specific on/off frequency. This angular motion creates an array of temporal oscillators along the radial direction of the disk. When the input test signal frequency matches one of the disk channel temporal frequencies, a positive build-up of charge occurs on the time integrating detector, indicating a frequency match. A simple disk system is demonstrated in the laboratory. The disk can also be used in a 2-D time and space integrating architecture, where radial sections of the disk are used for storing the columns of a DFT matrix used for temporal spectrum analysis.
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Charnotskii, Mikhail. "Sparse Spectrum Seas and Waves Statistics." In ASME 2013 32nd International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/omae2013-11462.
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A novel Sparse Spectrum (SS) model of the sea surface (M. Charnotskii, Proc. OMAE, 2011) is based on the conjecture that each surface realization contains a finite, possibly random, number of sinusoidal components with random frequency, phase and amplitude. Unlike the conventional FFT-based model, the number of spectral components forming the surface is determined by the sea state, but not the desired spatial resolution and domain size. A single constrain on the probability distribution of the wavenumbers, and the amplitude variances of the components and the number of spectral components allows the SS surface to conform to any prescribed spectral density. Spectra and single-point probability distribution of the surface elevations are not sensitive to the number of sparse spectral components. In order to gain information about the spectral sparsity of the surface elevation we use our SS-based Monte-Carlo model for the surface elevations to examine the sensitivity of the statistics of the individual waves to the number of the sparse spectral components. We analyze the probability distributions of the wave heights; mean zero crossing period, and exceedance probability of the crest height at a fixed point and over a given region of area for the wave records generated by the SS model and compare it to the statistics based on the traditional FFT-based Monte-Carlo models corresponding to the dense spectrum model. We use the Elfouhaily et.al. spectral model [3] that is common for the ocean remote sensing applications and discuss the sensitivity of the wave statistics to the spectral model choice.
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Martin, Fiore, Oussama Metatla, Nick Bryan-Kinns, and Tony Stockman. "Accessible Spectrum Analyser." In The 22nd International Conference on Auditory Display. Arlington, Virginia: The International Community for Auditory Display, 2016. http://dx.doi.org/10.21785/icad2016.041.
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This paper presents the Accessible Spectrum Analyser (ASA) developed as part of the DePic project (Design Patterns for Inclusive collaboration) at Queen Mary University of London. The ASA uses sonification to provide an accessible representation of frequency spectra to visually impaired audio engineers. The software is free and open source and is distributed as a VST plug-in under OSX and Windows. The aim of reporting this work at the ICAD 2016 conference is to solicit feedback about the design of the present tool and its more generalized counterpart, as well as to invite ideas for other possible applications where it is thought that auditory spectral analysis may be useful, for example in situations where line of sight is not always possible.
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Querry, Marvin R., and W. Patrick Roach. "Optical properties of polycrystalline molybdenum." In OSA Annual Meeting. Washington, D.C.: Optica Publishing Group, 1986. http://dx.doi.org/10.1364/oam.1986.ws4.
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Near-normal incidence reflectance of two different samples of mechanically polished, 99.97% pure, polycrystalline molybdenum was measured at 6121 spectral positions through the 0.0223–6.2-eV (180–50,000-cm−1) spectral range. A composite reflectance spectrum of Mo was obtained by objectively combining the reflectance spectra of the two samples. A Drude free-electron model was fitted to the composite reflectance spectrum in the 0.0223–0.062-eV region; the composite reflectance spectrum was thus extended into the 0–0.0223-eV region. In the 5.56–2000-eV region reflectance values obtained from the literature1 joined very well with the composite reflectance spectrum. Kramers-Kronig analysis of the reflectance spectrum provided the complex dielectric function, refractive index, and optical conductivity. We briefly review spectral values of these optical properties of Mo previously determined by other investigators, and we graphically compare results from our investigations with those from the previous investigations.
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Diatroptov, Mikhail, Victor Panchelyuga, Maria Panchelyuga, and Olga Seraya. "On the universal spectrum of periods in the time series of temperature fluctuations in starlings and rats." In International Conference "Computing for Physics and Technology - CPT2020". Bryansk State Technical University, 2020. http://dx.doi.org/10.30987/conferencearticle_5fce2772b9b793.28915214.
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The paper considers a spectral analysis based on Fourier transform of the time series in the temperature fluctuations in the bodies of common starlings (Sturnus vulgaris) and rats (mature Wistar males). The spectra of the periods in the starlings and rats contain the same sets of harmonics, so on this basis we can tell about a common spectrum. Interesting to note that the spectrum coincides with a previously revealed spectrum of the periods, obtained with the use of local fractal analysis by the all permutations method in the course of studies of time series of the alpha decay rate fluctuations. Despite different methods of the experimental data processing used in this work (spectral analysis based on Fourier transform and local fractal analysis by the all permutations method), as well as different raw experimental data (the temperature fluctuations and alpha-decay rate fluctuations), the same spectrum of periods was obtained. On this basis, we can consider the spectrum of periods as universal one.
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Brault, Janes W., and Mark C. Abrams. "DECOMP: A Fourier Transfom Spectra Decomposition Program." In High Resolution Fourier Transform Spectroscopy. Washington, D.C.: Optica Publishing Group, 1989. http://dx.doi.org/10.1364/hrfts.1989.pdp2.
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Current techniques for processing high resolution Fourier transform spectra revolve around interactive graphical display of the spectrum on a computer. The DECOMP spectrum decomposition program is designed explicitly for the reduction of Fourier transform spectra and focuses on reducing a spectrum into a list of line parameters. Basic methods of spectrum manipulation will be demonstrated and a IBM PC - compatible computer will be available for hands-on demonstrations of the process of spectrum analysis. Figures 1 and 2 illustrate the process of background subtraction: in Figure 1 a low resolution spectrum is generated by binning the high resolution spectrum and beneath the spectrum is a background correction function generated by creating a low resolution "minima" spectrum and smoothing the spectrum. The results of the background correction are given in Figure 2. Figure 3 illustrates a common problem in Fourier transform spectroscopy: the finite length of the interferogram introduces "ringing" into the spectrum. Using a filtered fitting routine in DECOMP the ringing can be effectively removed yielding a spectrum illustrated in Figure 4, in which several new spectral features that had been hidden beneath the ringing. An example of the atlas plots that can be generated using DECOMP is given in Figure 5.
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Scavuzzo, Rudolph J., George D. Hill, and Peter Saxe. "The “Spectrum Dip”: Dynamic Interaction of System Components." In ASME 2007 Pressure Vessels and Piping Conference. ASMEDC, 2007. http://dx.doi.org/10.1115/pvp2007-26757.
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In the early 1960s, many full sized surface combatants, submarines and structural models were tested with underwater explosive in order to evaluate the shock load to the ship and internal equipment and structures. Initially, shock spectra were calculated from base motion measurements of internal equipment and components. Attempts were made to envelop these spectra to develop shock design spectra inputs. At that time, earthquake engineers were using this enveloping method to develop design procedures from ground motion measurements to protect structures from earthquakes. However, for the measurements on ships, this procedure resulted in calculated loads that would have caused catastrophic failure of the equipment; yet the equipment had not failed on the ship tests. As a result, the data was reanalyzed over a period of over a year. It was concluded that the dynamic interaction of each component or structure reduced the measured spectral motion at the fixed-base frequencies of the structure by about an order of magnitude. In many cases, there was a dip in the shock spectra at the fixed-base frequencies: the “spectrum dip” phenomenon. This reanalysis led to shock spectra design curves for navy ships. This paper will present a review of an experimental study and an analytical model to explain the effect of dynamic interaction on the shock or response spectrum. In addition, a practical example of interaction of four single mass dynamic systems mounted on a realistic deck and subjected to a high impact shock input was studied by the authors.
Reports on the topic "Spectrum"
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Paul, Satashree. Autism Spectrum Disorder. Science Repository, February 2021. http://dx.doi.org/10.31487/sr.blog.26.
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Simakov, S. Evaluation of the Prompt Gamma-ray Spectrum from Spontaneous Fission of 252Cf. IAEA Nuclear Data Section, February 2024. http://dx.doi.org/10.61092/iaea.bz1p-e3yc.
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The energy spectra, multiplicities and average energies of the prompt, total and delayed γ-rays accompanying the spontaneous fission of 252Cf were collected from the literature and dedicated databases. They were carefully analysed for consistency with a view to producing reference data for usage in various applications. This could be accomplished for the prompt fission gamma ray spectrum up to 20 MeV since dozens of measurements exist and reasonably agree. The prompt fission gamma ray spectrum (PFGS) was non-model evaluated by fitting the preselected experimental data with the help of the generalized least-squares (GLS) code GMA. The resulting spectrum could be considered as a reference for the γ-ray energies from 0.1 to 20 MeV with uncertainties varying between ≈ 3 and 25%. This reference gamma spectrum will be a substantial contribution to the precise and complete characterisation of the 252Cf source since the prompt fission neutron spectrum (PFNS), which has been accepted as a standard for a long time, has comparable uncertainties. The average gamma multiplicity and energy were also surveyed and used to derive the recommended values. The prompt X- and γ-ray energy spectra below ≈ 100 keV and delayed photon spectra in the whole energy range, as well as their multiplicities, are still seldomly and incompletely measured, that excepts an evaluation based on experimental data. The comparison with existing theoretical prompt and delayed 252Cf(s.f.) γ-spectra or with those presented in the major evaluated cross section libraries explored their incompleteness or deviations from the evaluated PFGS. The existing measurements of the pionic and muonic radioactivity of 252Cf(s.f.) and 235U(nth,f) were reviewed and the potential impact of gammas from the π0 decay on the high energy part of the PFGS was investigated.
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Lee, Amy Sarah. Determination of the Spectral Index in the Fission Spectrum Energy Regime. Office of Scientific and Technical Information (OSTI), May 2016. http://dx.doi.org/10.2172/1253539.
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Yavorsky, Joseph P. Control of the Spectrum via Dominant Spectrum Knowledge Enables Information Superiority. Fort Belvoir, VA: Defense Technical Information Center, April 1999. http://dx.doi.org/10.21236/ada364077.
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Silvester, J. A., and A. Polydoros. Adaptive Spread Spectrum Networks. Fort Belvoir, VA: Defense Technical Information Center, September 1987. http://dx.doi.org/10.21236/ada187154.
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Pursley, Michael B., and Dilip V. Sarwate. Spread Spectrum Radio Networks. Fort Belvoir, VA: Defense Technical Information Center, October 1987. http://dx.doi.org/10.21236/ada188914.
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Kalyanasundaram, Bala. Dynamic Spectrum Allocation Algorithms. Fort Belvoir, VA: Defense Technical Information Center, January 2002. http://dx.doi.org/10.21236/ada418179.
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Lehnert, J., J. Shea, N. Shroff, W. Stark, and T. Wong. Utilizing Spectrum Efficiently (USE). Fort Belvoir, VA: Defense Technical Information Center, February 2011. http://dx.doi.org/10.21236/ada563687.
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Pruhs, Kirk, and Bala Kalyanasundaram. Dynamic Spectrum Allocation Algorithms. Fort Belvoir, VA: Defense Technical Information Center, December 2002. http://dx.doi.org/10.21236/ada420598.
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Mankowski, Adam M. Direct Sequence Spread Spectrum. Fort Belvoir, VA: Defense Technical Information Center, August 2000. http://dx.doi.org/10.21236/ada387171.
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