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排序方式: 共有86条查询结果,搜索用时 10 毫秒
1.
Ana Gavrovska Vesna Bogdanović Irini Reljin Branimir Reljin 《Computer methods and programs in biomedicine》2014
Having in mind the availability of electronic stethoscopes, phonocardiograms (PCGs) have become popular for cardiovascular functionality monitoring and signal processing applications. Detection of fundamental heart sounds (HSs), S1s and S2s, is considered to be a crucial step in PCG analysis. Electrocardiogram (ECG), noted as a reference signal, is often synchronously recorded in order to simplify the S1/S2 detection process. Nevertheless, electronic stethoscopes are frequently used without additional ECG equipment. We propose a new algorithm for automatic fundamental HSs detection via: joint time-frequency representation based on pseudo affine Wigner–Ville distribution (PAWVD), Haar wavelet lifting scheme (Haar-LS), normalized average Shannon energy (NASE) and autocorrelation. The performance of the proposed algorithm was calculated on both normal (50) and pathological (75) PCG recordings, eight seconds long each, contributed by 125 different pediatric patients. The algorithm showed relatively high recall (90.41%) and precision (96.39%) rates of S1/S2 detection procedure in a variety of PCG signals, without ECG as a reference. Furthermore, it indicated the ability to overcome splitting within the S1/S2 heart sounds. 相似文献
2.
Stojanovic D. Djurovic I. Vojcic B.R. 《Wireless Communications, IEEE Transactions on》2009,8(6):2877-2880
Multicarrier techniques based on affine Fourier transform (AFT) have been recently proposed for transmission in the wireless channels. The AFT represents a generalization of the Fourier and fractional Fourier transform. We derive the exact and approximated interference power, upper bound and measure of applicability for the AFT based multicarrier (AFT-MC) system. It is demonstrated that the AFT-MC system effectively minimizes interference in time-varying multipath channels with line-of-sight component and narrow beamwidth of scattered components that often occurs in aeronautical and satellite communications. 相似文献
3.
Dragan Kandic Branimir Reljin 《International Journal of Circuit Theory and Applications》1994,22(3):163-174
A new class of non-canonic, driving-point immittance realizations of passive, common-ground, transformerless, two-element-kind RLC networks with minimum number of nodes is presented. Six new algorithms of realization are developed by application of canonic, orthogonal matrix transformations with reduced number of degrees of freedom. the number of applied RLC elements of one kind can be minimized and of the other kind reduced, while their parameter values are calculated directly in a linear way. 相似文献
4.
In the paper, thermal use of solar energy as well as prospects and problems of its utilisation in Croatia have been given. The National Solar Energy Program, SUNEN, has been established to stimulate the usage of solar energy. The main goals of the program are the assessment of technical and economically viable solar potential in order to define real objectives and tasks to provide use of exploitable indigenous clean and renewable energy potential. The Program addresses benefits, the most promising solar applications and solar potential. Much attention has been given to identification of obstacles and barriers in the process of solar technology dissemination. SUNEN is an initiative to increase solar energy use and to become more compatible with the present renewable energy sources policy in EU and Mediterranean countries. The program proposes twelve different types of thermal solar energy systems, which could be multiplied up to 28 000 installations until the year 2010 with annual heat recovery of approximately 1,5 TWh (5,4 PJ). 相似文献
5.
Estimation of FAO Blaney-Criddle b Factor by RBF Network 总被引:2,自引:0,他引:2
Slavisa Trajkovic Miomir Stankovic Branimir Todorovic 《Canadian Metallurgical Quarterly》2000,126(4):268-270
This technical note presents the application of a Radial Basis Function (RBF) network to estimate the FAO Blaney-Criddle b factor. Tabular b values are given in the United Nations Food and Agriculture Organization Irrigation and Drainage Paper Number 24. The b values obtained by the RBF network are compared to the appropriate b values produced using regression equations. The RBF network predicted b values better than the regression equations. An example is given to illustrate the simplicity and accuracy of the RBF network for b factor estimation. 相似文献
6.
7.
Zoran ?ujovi? Radivoje Sreji? Dušan Vu?eli? Dragomir Vitorovi? Branimir Jovan?i?evi? 《Fuel》1995,74(12):1903-1909
A sample of kerogen from Aleksinac oil shale was examined by high-resolution solid-state 13C n.m.r. spectroscopy. The presence and relative proportions of kerogen structural units were estimated using a combination of NQS and T1C methods with a peak-synthesis technique applied to the 13C CP—MAS spectrum. Relaxation parameters from these experiments were used to estimate differences in relative ‘mobility’ of various structural units. The kerogen was found to be highly aliphatic and to contain 79% long-chain aliphatic plus alicyclic structures, as well as 9% aromatic structures. These findings are in good agreement with the characterization of the same kerogen from its oxidation products. 相似文献
8.
Wireless sensor networks are energy constrained since sensors operate with limited battery capacity. Thus, energy consumption
is one of the most critical issues in the design of routing protocols. In addition, the link quality needs to be taken into
account in the route decision for a wireless multihop network in order to efficiently exploit the inherent spatial diversity.
In this paper we consider energy-aware and link-adaptive routing strategies for UWB (Ultra Wide Band) sensor networks. We
utilize the ranging capabilities offered by UWB and employ adaptive modulation to take advantage of favorable link conditions.
Different routing metrics are proposed based on the availability of sensor node’s location, link quality and next hop battery
capacity information. These routing metrics integrate the measure of next hop remaining battery capacity with the throughput
performance measures, Maximum Forward Progress (MFP) or Maximum Information Progress (MIP). The effectiveness of these metrics
is evaluated in different simulation scenarios in terms of network throughput and lifetime for both random and grid sensor
network topologies.
Jinghao Xuis a D.Sc. candidate of the Department of Electrical and Computer Engineering at the George Washington University. He received
his B.Sc. and M.S. degrees in telecommunication and electrical engineering from the Tianjin University, China, in 1993 and
1996, respectively. From 1996 to 2001, he was with Research Institute of Telecommunication Transmission of Ministry of Information
Industry, Beijing, China, and China Wireless Telecommunication Standards group, where he was involved in the standardization
of IMT-2000 communication systems for China. His research interests include performance evaluation and modeling of wireless
ad hoc networks, Ultra Wide Band systems and multiuser detection techniques.
Bojan M. Peric received the B.S. degree in electrical engineering from the University of Belgrade, Belgrade, Serbia and Montenegro in 2001.
He is currently working toward the D.Sc. degree in electrical engineering at the George Washington University, Washington,
DC. His research interests include wireless communications, with an emphasis on ad hoc networks.
Branimir R. Vojcic is a professor in, and a past Chairman of, the Department of Electrical and Computer Engineering at the George Washington
University. He has received his Dipl. Ing., M.Sc. and D.Sc. degrees from the University of Belgrade in Serbia and Montenegro
in 1980, 1986 and 1989, respectively. His current research interests are in the areas of communication theory, performance
evaluation and modeling mobile and wireless networks, mobile internet, code division multiple access, multiuser detection,
adaptive antenna arrays, space-time coding and ad-hoc networks. He has also been an industry consultant and has published
and lectured extensively in these areas. He co-authored the book: The cdma2000 System for Mobile Communications. Dr Vojcic
received NSF CAREER Award in 1995. He is a Senior Member of IEEE, was an Associate Editor for IEEE Communications Letters
and is presently an Associate Editor for Journal on Communications and Networks. 相似文献
9.
Information efficiency of multihop packet radio networks with channel-adaptive routing 总被引:2,自引:0,他引:2
Souryal M.R. Vojcic B.R. Pickholtz R.L. 《Selected Areas in Communications, IEEE Journal on》2005,23(1):40-50
This paper analyzes the benefit of adaptive routing based on knowledge of the channel state information in multihop, ad hoc wireless networks that use direct-sequence code-division multiple access. Cross-layer, channel-adaptive routing exploits the inherent spatial diversity of multihop wireless networks to select links with favorable channel conditions. The information efficiency, an extension of a previously used measure called expected progress, is used to evaluate performance. Results show that, combined with adaptive modulation, adaptive routing can improve performance in ad hoc networks by a factor of four to five in channels with Rayleigh fading and lognormal shadowing. The lack of position information in the routing decision would reduce performance by 25%. New approaches to channel-adaptive routing that enable rapid adaptivity to channel conditions are discussed. 相似文献
10.
Recent advances in micro-magnetic resonance imaging have shown the possibility of in vivo assessment of trabecular bone architecture. However, the small feature size and relatively low signal-to-noise ratio (SNR) achievable in vivo cause the intensity histogram to be unimodal. The critical first step in the processing of these images is the extraction of bone volume fraction for each voxel. Here, we propose a local threshold algorithm (LTA) that determines the marrow intensity value in the neighborhood of each voxel based on nearest-neighbor statistics. Using the local marrow intensities we threshold the image and scale the intensities of voxels partially occupied by bone to produce a marrow volume fraction map of the trabecular bone region. We show that structural parameters derived with the LTA are highly correlated with those obtained with the previously published histogram deconvolution algorithm (HDA) and that the LTA is robust to image noise corruption. The LTA is found to correctly identify trabeculae with a significantly higher reliability than HDA. Finally, we demonstrate that the LTA is superior in preserving connectivity by showing for 75 in vivo images that the genus of the trabecular bone surface is always higher than when processed with the HDA. 相似文献