检索结果-内蒙古大学图书馆

arXiv 2023年

作者： Yarach, Uten Chatnuntawech, Itthi Liao, Congyu Teerapittayanon, Surat Iyer, Siddharth Srinivasan Kim, Tae Hyung Haldar, Justin Cho, Jaejin Bilgic, Berkin Hu, Yuxin Hargreaves, Brian Setsompop, Kawin Radiologic Technology Department Associated Medical Sciences Chiang Mai University Chiang Mai Thailand National Nanotechnology Center National Science and Technology Development Agency Pathum Thani Thailand Department of Radiology Stanford University StanfordCA United States Department of Electrical Engineering Stanford University StanfordCA United States Department of Electrical Engineering and Computer Science Massachusetts Institute of Technology CambridgeMA United States Department of Computer Engineering Hongik University Seoul Korea Republic of Signal and Image Processing Institute Ming Hsieh Department of Electrical and Computer Engineering University of Southern California Los AngelesCA United States Athinoula A. Martinos Center for Biomedical Imaging Massachusetts General Hospital CharlestownMA United States Department of Radiology Harvard Medical School BostonMA United States Department of Bioengineering Stanford University StanfordCA United States Packard Electrical Engineering Building 350 Jane Stanford Way StanfordCA94305 United States

Purpose: We implemented the blip-up, blip-down circular echo planar imaging (BUDA-cEPI) sequence with readout and phase partial Fourier to reduced off-resonance effect and T2* blurring. BUDA-cEPI reconstruction with S-based low-rank modeling of local k-space neighborhoods (S-LORAKS) is shown to be effective at reconstructing the highly under-sampled BUDA-cEPI data, but it is computationally intensive. Thus, we developed an ML-based reconstruction technique termed "BUDA-cEPI RUN-UP" to enable fast reconstruction. Methods: BUDA-cEPI RUN-UP – a model-based framework that incorporates off-resonance and eddy current effects was unrolled through an artificial neural network with only six gradient updates. The unrolled network alternates between data consistency (i.e., forward BUDA-cEPI and its adjoint) and regularization steps where U-Net plays a role as the regularizer. To handle the partial Fourier effect, the virtual coil concept was also incorporated into the reconstruction to effectively take advantage of the smooth phase prior, and trained to predict the ground-truth images obtained by BUDA-cEPI with S-LORAKS. Results: BUDA-cEPI with S-LORAKS reconstruction enabled the management of off-resonance, partial Fourier, and residual aliasing artifacts. However, the reconstruction time is approximately 225 seconds per slice, which may not be practical in a clinical setting. In contrast, the proposed BUDA-cEPI RUN-UP yielded similar results to BUDA-cEPI with S-LORAKS, with less than a 5% normalized root mean square error detected, while the reconstruction time is approximately 3 seconds. Conclusion: BUDA-cEPI RUN-UP was shown to reduce the reconstruction time by ~88x when compared to the state-of-the-art technique, while preserving imaging details as demonstrated through DTI application. © 2023, CC BY.

关键词： Magnetic resonance imaging

来源：评论

学校读者我要写书评

暂无评论

Some statistical consideration of azimuth and inclination angles determination based on walk-away VSP data in Python 5

Some statistical consideration of azimuth and inclination an...

引用

5th International Conference on Applied Geophysics, AG 2019

作者： Zarȩba, Mateusz Danek, Tomasz Stefaniuk, Michal AGH University of Science and Technology Department of Geoinformatics and Applied Computer Science Krakow Poland AGH University of Science and Technology Department of Fossil Fuels Krakow Poland GK Processing R and D Department of Seismic Signal Processing Center Balice Poland

It is a common knowledge that proper inclinations and azimuth angle determination is a critical step in processing and interpretation of walk-away VSP data. Additionally, an in-depth analysis of the uncertainty of these interpreted values requires the introduction of measurement errors. In this contribution, we present a statistical analysis of obtained polarization angles from three-component, multi-depth level, walk-away VSP using Python 3 programming language. Our analysis is presented in the context of different processing sequences and correlation with local features of the geological medium. We show that the obtained values of polarization angles and their errors can be strongly affected by processing sequence and-when done correctly-can give addition inside into features of analysis medium. Moreover, in some cases, even a presence of saturation can be express by polarization angles variations. Additionally, we examined the impact of well-casing on interpretational values of polarization angles. © 2019 The Authors, published by EDP sciences.

关键词： Python

来源：评论

学校读者我要写书评

暂无评论

XR-Cockpit: a comparison of VR and AR solutions on an interactive training station

XR-Cockpit: a comparison of VR and AR solutions on an intera...

引用

International Conference on Emerging Technologies and Factory Automation (ETFA)

作者： Ariel Caputo Sergiu Jacota Serhiy Krayevskyy Marco Pesavento Fabio Pellacini Andrea Giachetti Department of Computer Science University of Verona Verona Italy Centre for Vision Speech and Signal Processing University of Surrey Guildford Surrey United Kingdom Department of Computer Science Sapienza University of Rome Rome Italy

ISBN: (数字)9781728189567

ISBN: (纸本)9781728189574

One of the most challenging aspects of the implementation of Virtual/Mixed reality training systems is the effective simulation of real-world manipulation of the physical devices included in control interfaces like buttons, sliders, levers, knobs, etc. In this paper we describe a mockup airplane cockpit (XR-Cockpit), featuring interactive components of this kind that demonstrate the feasibility of effective simulations of device manipulation using low cost hand tracking technology and gesture recognition. Based on this system, we performed a user study to compare the effectiveness of the interaction with virtual tools using different visualization solutions: immersive VR, optical and video see-through based MR. In our study, we also checked how well it is possible to perform manipulation of real objects wearing the two video see-through solutions. The analysis of the experimental results provides useful guidelines for the design of Virtual and Mixed Reality training systems involving virtual and physical actions on manipulation devices.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Fast Radix-32 Approximate DFTs for 1024-Beam Digital RF Beamforming

arXiv

引用

arXiv 2022年

作者： Madanayake, A. Cintra, R.J. Akram, N. Ariyarathna, V. Mandal, S. Coutinho, V.A. Bayer, F.M. Coelho, D. Rappaport, T.S. Electrical and Computer Engineering Department Florida International University United States Signal Processing Group Ufpe Brazil School of Science and Mathematics Howard Payne University TX United States Electrical Computer and Systems Engineering Department Case Western Reserve University United States Universidade Federal Rural de Pernambuco Recife Brazil Department of Statistics Lacesm Federal University of Santa Maria Brazil AB Calgary Canada Nyu Wireless Department of Electrical Engineering Tandon School of Engineering New York University BrooklynNY11220 United States

The discrete Fourier transform (DFT) is widely employed for multi-beam digital beamforming. The DFT can be efficiently implemented through the use of fast Fourier transform (FFT) algorithms, thus reducing chip area, power consumption, processing time, and consumption of other hardware resources. This paper proposes three new hybrid DFT 1024-point DFT approximations and their respective fast algorithms. These approximate DFT (ADFT) algorithms have significantly reduced circuit complexity and power consumption compared to traditional FFT approaches while trading off a subtle loss in computational precision which is acceptable for digital beamforming applications in RF antenna implementations. ADFT algorithms have not been introduced for beamforming beyond N = 32, but this paper anticipates the need for massively large adaptive arrays for future 5G and 6G systems. Digital CMOS circuit designs for the ADFTs show the resulting improvements in both circuit complexity and power consumption metrics. Simulation results show similar or lower critical path delay with up to 48.5% lower chip area compared to a standard Cooley-Tukey FFT. The time-area and dynamic power metrics are reduced up to 66.0%. The 1024-point ADFT beamformers produce signal-to-noise ratio (SNR) gains between 29.2-30.1 dB, which is a loss of ≤ 0.9 dB SNR gain compared to exact 1024-point DFT beamformers (worst case) realizable at using an FFT. Copyright © 2022, The Authors. All rights reserved.

关键词： Beamforming

来源：评论

学校读者我要写书评

暂无评论

Fault Diagnosis of Wind Energy Conversion Systems Using Gaussian Process Regression-based Multi-Class Random Forest

引用

IFAC-PapersOnLine 2022年第6期55卷 127-132页

作者： Majdi Mansouri Radhia Fezai Mohamed Trabelsi Hajji Mansour Hazem Nounou Mohamed Nounou Electrical and Computer Engineering Program Texas A&M University at Qatar Doha Qatar Department of Mathematics and Sciences Prince Sultan University Riyadh 11586 Saudi Arabia Research Laboratory of Automation Signal Processing and Image National Engineering School of Monastir 5019 Tunisia Electronic and Communications Engineering Department Kuwait College of Science and Technology P. O. Box 27235 Kuwait Higher Institute of Applied Science and Technology of Kasserine University of Kairouan PO Box 471 1200 Kasserine Tunisia Chemical Engineering Program Texas A&M University at Qatar Doha Qatar

This work proposes a new fault diagnosis approach for a wind energy conversion (WEC) system. The proposed technique merges the benefits of feature extraction based on Gaussian Process Regression (GPR) and Multi-Class Random Forest (MCRF)-based fault classification where instances are classified into one or more classes. In the developed GPR-MCRF approach, the nonlinear statistical features including the mean vector M GPR and the variance matrix C GPR are computed using the GPR model with aim of extracting the most relevant features from the WEC system. Then, these features are introduced to the RF classifier for classification and diagnosis purposes. Therefore, the application of the GPR-MCRF technique for WEC systems aims to enhance the use of the classical raw data-based MCRF and diagnosis accuracy. Three kinds of faults (wear-out, open-circuit, and short-circuit faults) are considered in this work. Different case studies are investigated in order to illustrate the effectiveness and robustness of the developed technique compared to the state-of-the-art methods. The obtained results show that the the developed GPR-MCRF technique is an effective feature extraction and fault diagnosis technique for WEC systems.

关键词： Random Forest (RF) Multi-Class Gaussian Process Regression (GPR) Fault Diagnosis Wind Energy Conversion Systems

来源：评论

学校读者我要写书评

暂无评论

SWAN: Swarm-based low-complexity scheme for PAPR reduction

arXiv

引用

arXiv 2020年

作者： Abanto-Leon, Luis F. Sim, Gek Hong Hollick, Matthias Boonkajay, Amnart Adachi, Fumiyuki Lab Technical University of Darmstadt Department of Computer Science Germany Singapore Wireless Signal Processing Research Group ROEC Tohoku University Japan

Cyclically shifted partial transmit sequences (CS-PTS) has conventionally been used in SISO systems for PAPR reduction of OFDM signals. Compared to other techniques, CS-PTS attains superior performance. Nevertheless, due to the exhaustive search requirement, it demands excessive computational complexity. In this paper, we adapt CS-PTS to operate in a MIMO framework, where singular value decomposition (SVD) precoding is employed. We also propose SWAN, a novel optimization method based on swarm intelligence to circumvent the exhaustive search. SWAN not only provides a significant reduction in computational complexity, but it also attains a fair balance between optimality and complexity. Through simulations, we show that SWAN achieves near-optimal performance at a much lower complexity than other competing approaches. Copyright © 2020, The Authors. All rights reserved.

关键词： Orthogonal frequency division multiplexing

来源：评论

学校读者我要写书评

暂无评论

Fluid Antennas-Enabled Multiuser Uplink: A Low-Complexity Gradient Descent for Total Transmit Power Minimization

arXiv

引用

arXiv 2023年

作者： Hu, Guojie Wu, Qingqing Xu, Kui Ouyang, Jian Si, Jiangbo Cai, Yunlong Al-Dhahir, Naofal The College of Communication Engineering Rocket Force University of Engineering Xi’an710025 China The Department of Electronic Engineering Shanghai Jiao Tong University Shanghai200240 China The College of Communications Engineering The Army of Engineering University Nanjing210007 China The Institute of Signal Processing and Transmission Nanjing University of Posts and Telecommunications Nanjing210003 China The Integrated Service Networks Lab of Xidian University Xi’an710100 China The College of Information Science and Electronic Engineering Zhejiang University Hangzhou310027 China The Department of Electrical and Computer Engineering The University of Texas at Dallas RichardsonTX75080 United States

We investigate multiuser uplink communications from multiple single-antenna users to a base station (BS), which is equipped with multiple fluid antennas (FAs) and adopts zero-forcing receivers to decode multiple signals. We aim to optimize antennas’ positions at the BS, to minimize the total transmit power of all users subject to the minimum rate requirement. After applying transformations, we show that the problem is equivalent to minimizing the sum of each eigenvalue’s reciprocal of a matrix, which is a function of all antennas’ positions at the BS. Subsequently, the projected gradient descent (PGD) method is utilized to find a locally optimal solution. In particular, different from the latest related work, we exploit the eigenvalue decomposition to successfully derive a closed-form gradient for the PGD, which facilitates the practical implementation greatly. We demonstrate by simulations that via careful optimization for all antennas’ positions in our proposed design, the total transmit power of all users can be decreased significantly as compared to competitive benchmarks. Copyright © 2023, The Authors. All rights reserved.

关键词： Antennas

来源：评论

学校读者我要写书评

暂无评论

SBERT-WK: A sentence embedding method by dissecting BERT-based word models

arXiv

引用

arXiv 2020年

作者： Wang, Bin Jay Kuo, C.-C. Ming-Hsieh Department of Electrical and Computer Engineering and Signal Image Processing Institute University of Southern California Los AngelesCA90089-2584 United States Ming-Hsieh Department of Electrical and Computer Engineering Department of Computer Science and Signal Image Processing Institute University of Southern California Los AngelesCA90089-2584 United States

Sentence embedding is an important research topic in natural language processing (NLP) since it can transfer knowledge to downstream tasks. Meanwhile, a contextualized word representation, called BERT, achieves the state-of-the-art performance in quite a few NLP tasks. Yet, it is an open problem to generate a high quality sentence representation from BERTbased word models. It was shown in previous study that different layers of BERT capture different linguistic properties. This allows us to fusion information across layers to find better sentence representation. In this work, we study the layer-wise pattern of the word representation of deep contextualized models. Then, we propose a new sentence embedding method by dissecting BERT-based word models through geometric analysis of the space spanned by the word representation. It is called the SBERT-WK method. No further training is required in SBERTWK. We evaluate SBERT-WK on semantic textual similarity and downstream supervised tasks. Furthermore, ten sentencelevel probing tasks are presented for detailed linguistic analysis. Experiments show that SBERT-WK achieves the state-of-the-art performance. Our codes are publicly available at the Github1. Copyright © 2020, The Authors. All rights reserved.

关键词： Embeddings

来源：评论

学校读者我要写书评

暂无评论

Quantifying high-order interdependencies on individual patterns via the local O-information: Theory and applications to music analysis

引用

Physical Review Research 2022年第1期4卷 013184-013184页

作者： Tomas Scagliarini Daniele Marinazzo Yike Guo Sebastiano Stramaglia Fernando E. Rosas Dipartimento Interateneo di Fisica Universitá degli Studi Aldo Moro Bari and INFN Italy Department of Data Analysis Ghent University Belgium Department of Computer Science Hong Kong Baptist University Hong Kong Data Science Institute Imperial College London United Kingdom Center of Innovative Technologies for Signal Detection and Processing (TIRES) Universitá degli Studi Aldo Moro Italy Centre for Psychedelic Research Department of Brain Science Imperial College London United Kingdom Centre for Complexity Science Imperial College London United Kingdom

High-order, beyond-pairwise interdependencies are at the core of biological, economic, and social complex systems, and their adequate analysis is paramount to understand, engineer, and control such systems. This paper presents a framework to measure high-order interdependence that disentangles their effect on each individual pattern exhibited by a multivariate system. The approach is centered on the local O-information, a new measure that assesses the balance between synergistic and redundant interdependencies at each pattern. To illustrate the potential of this framework, we present a detailed analysis of music scores from J. S. Bach, which reveals how high-order interdependence is deeply connected with highly nontrivial aspects of the musical discourse. Our results place the local O-information as a promising tool of wide applicability, which opens other perspectives for analyzing high-order relationships in the patterns exhibited by complex systems.

关键词： Complex systems Information & communication theory

来源：评论

学校读者我要写书评

暂无评论

Yule-Walker Equations Using Higher Order Statistics for Nonlinear Autoregressive Model

Yule-Walker Equations Using Higher Order Statistics for Nonl...

引用

2019 signal processing Symposium, SPSympo 2019

作者： Libal, Urszula Johansson, Karl H. School of Electrical Engineering and Computer Science KTH Royal Institute of Technology Stockholm Sweden Signal Processing Systems Department Wroclaw University of Science and Technology Wroclaw Poland

ISBN: (纸本)9781728117157

The paper presents the derivation of Yule-Walker equations for the nonlinear autoregressive model NAR(p) of a time-series. The proposed method allows for easy calculation of parameters of the model. In the determined equations, higher order statistics are used, instead of autocovariances. For the linear autoregressive model AR(p), the standard Yule-Walker equations are directly based on autocovariances of time-series, or equivalently autocorrelations if the equations are rescaled. Unfortunately, it does not apply for nonlinear model. The authors show a compact matrix notation of Yule-Walker equations for the nonlinear autoregressive model with the nonlinearity of polynomial type of degree 2, with the use of higher order statistics up to 4th order, and numerical examples for electromyography signals for different hand movements. © 2019 IEEE.

关键词： Time series

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：