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He T.,UESTC | Rui D.,UESTC | Yong H.,UESTC | Zhang J.,UESTC
International Conference on Signal Processing Proceedings, ICSP | Year: 2017

In this paper, a phased array beamforming method based on the rotational platform is proposed. According to this method, the height of a platform can be measured accurately by adjusting the azimuth and elevation angles to keep the beam always point to the nadir point. Thus, the phased array altimeter needs to compensate the intersection change of the beam-point and the nadir point as a consequence of the platform translation and rotation. This paper deduces functions of angle error and phase compensation to calibrate the beam-point by establishing motion model of the platform, provides the method of weight calculating, and analyzes the update rate of weight. The curves illustrating the changes in directions of beam point as azimuth and elevation change respectively are provided by simulating. Finally, by means of simulation, making comparison between compensated and non-compensated antenna beam direction, we find the non-compensated beam is off nadir point with the changing motion of platform, while after compensating, the beam can be calibrated and pointed to the nadir again. © 2016 IEEE.

Lai Y.,Waseda University | Kamata S.-I.,Waseda University | Fu Z.,UESTC
Proceedings of the 15th IAPR International Conference on Machine Vision Applications, MVA 2017 | Year: 2017

Microscopic images are quite helpful for us to observe the details of cells because of its high resolution. Furthermore it can benefit biologists and doctors to view the cell structure from any aspect by using a serial images to generate 3D cell structure. However each cell slice is placed at the microscopy respectively, which will bring in the arbitrary rotation and translation among the serial slices. What's more, the sectioning process will destroy the cell structure such as tearing or warping. Therefore we must register the serial slices before rendering the volume data in 3D. In this paper we propose a robust registration algorithm based on an improved 3D Hilbert scam search. Besides we put forward a simple but effective method to remove false matching in consecutive images. Finally we correct the local deformation based on optical-flow theory and adopt multi-resolution method. Our algorithm is tested, on a serial microscopy kidney cell images, and the experimental results show how accurate and robust of our method is. © 2017 MVA Organization All Rights Reserved.

Cheng Z.,University of Electronic Science and Technology of China | He Z.,UESTC | Zhang S.,Chengdu China e mail miaomiao871@sina.com | Li J.,University of Florida
IEEE Transactions on Signal Processing | Year: 2017

A multiple-input multiple-output (MIMO) radar has great flexibility to design the transmit beampattern via selecting the probing waveform. The idea of current transmit beampattern design is to approximate the disired transimit beampattern. In this paper, under the constant modulus constraint, two algorithms are proposed to design the probing waveform directly. In the first algorithm, the optimization criterion is minimizing the squared-error between the designed beampattern and the given beampattern. Since the objective function is a nonconvex fourth-order polynomial and the constant modulus constraint can be regarded as many nonconvex quadratic equality constraints, an efficient alternating direction method of multipliers (ADMM) algorithm, whose convergence speed is very fast, is proposed to solve it. In the second algorithm, the criterion is minimizing the absolute-error between the designed beampattern and the given beampattern. This nonconvex problem can be formulated as $l_{1}$-norm problem, which can be solved through a double-ADMM (DADMM) algorithm. Finally, we assess the performance of the two proposed algorithms via numerical results. IEEE

Wang Y.,University of Electronic Science and Technology of China | Xia W.,University of Electronic Science and Technology of China | He Z.,UESTC | Li H.,Stevens Institute of Technology | Petropulu A.,Electrical &amp
IEEE Transactions on Signal Processing | Year: 2017

In this paper, we consider polarimetric adaptive detection in compound Gaussian clutter whose covariance matrix (CM) has a Kronecker structure. We derive the Cram{\'e}r-Rao bound of a Kronecker structured covariance matrix estimate and analyze the constant false alarm rate property of the adaptive subspace matched filter detector that uses Kronecker structured estimates. We provide a general expression for the average signal-to-clutter ratio loss (SCRL) as a function of the mean-square error of the covariance estimate. The aforementioned expression is helpful in determining how many samples are required in order to achieve a desired average SCRL level in practical scenarios. Based on that expression, we show that the required sample size can be effectively reduced by exploiting the Kronecker structure of the clutter CM. We also derive the asymptotic detection performance of the adaptive subspace matched filter. The analysis of SCRL and detection performance can be extended to more general scenarios, especially when the maximum likelihood estimate of the structured covariance matrix involves solving fixed point equations. Numerical simulations validate the merits of the proposed methods. IEEE

Chen H.,UESTC | Chen H.,Duke University | Benson T.,Duke University
SOSR 2017 - Proceedings of the 2017 Symposium on SDN Research | Year: 2017

SDN controllers demand tight performance guarantees over the control plane actions performed by SDN switches. For example, traffic engineering techniques that frequently reconfigure the network require guarantees on the speed of gathering data from the network and the speed of reconfiguring the network. Yet, modern switches provide no guarantees for these control plane actions, e.g., inserting rules or gathering statistics. In fact, initial experiments demonstrate that unpredictability in control plane actions, specifically rule insertion, can inflate application completion times by a factor of 4X! In this paper, we present Mercury, a framework that offers a novel method for efficiently and practically managing switch TCAM to enable strict performance guarantees. Specifically, Mercury builds on the fundamental properties of TCAMs and provides guarantees by trading-off a nominal amount of TCAM space for assured performance. Our preliminary evaluations show that with less than 10% overheads, Mercury provides guarantees of 10ms insertion time and improves application performance by a factor 2X to 5X. © 2017 ACM.

Liu Z.,University of California at Riverside | Tan S.X.-D.,University of California at Riverside | Wang H.,UESTC | Swarup S.,University of California at Riverside | Gupta A.,Intel Corporation
Proceedings of the Asia and South Pacific Design Automation Conference, ASP-DAC | Year: 2013

This paper proposes a new thermal nonlinear modeling technique for packaged integrated systems. Thermal behavior of complicated systems like packaged electronic systems may exhibit nonlinear and temperature dependent properties. As a result, it is difficult to use a low order linear model to approximate the thermal behavior of the packaged integrated systems without accuracy loss. In this paper, we try to mitigate this problem by using piecewise linear (PWL) approach to characterizing the thermal behavior of those systems. The new method (called ThermSubPWL), which is the first proposed approach to nonlinear thermal modeling problem, identifies the linear local models for different temperature ranges using the subspace identification method. A linear transformation method is proposed to transform all the identified linear local models to the common state basis to build the continuous piecewise linear model. Experimental results validate the proposed method on a realistic packaged integrated system modeled via the multi-domain/physics commercial tool, COMSOL, under practical power signal inputs. The new piecewise models can lead to much smaller model order without accuracy loss, which translates to significant savings in both the simulation time and the time required to identify the reduced models compared to applying the high order models. © 2013 IEEE.

Zhong H.S.,UESTC | Guan L.,Automotive Semiconductor Supplier | You W.,UESTC
SAE Technical Papers | Year: 2015

The torque sensing module is an important part of EPS (Electronic Power Steering) system. There are various solutions in the market based on different technologies i.e. Potential meter, Inductive and Hall sensing. As a trend, more and more EPS system integrators adopt Hall-based torque sensing solution, most of which consist of a magnetic ring, a magnetic flux detector to read the magnetic flux from the magnetic ring and a flux conductor/concentrator to lead the magnetic signal to a Hall device to convert magnetic flux level to electronic signal. However, available solutions require high mechanical precision from the magnetic flux detector and conductor/concentrator. Also, the magnetic ring in the existing solution is magnetized after its preformation which causes a lower signal-to-noise ratio at the input of the entire system due to the process and brings about less accuracy of the torque sensing module. In order to overcome these obstacles, a new torque sensing module design based on Hall sensing principles is proposed in this paper. This article provides a brief background of the current market and technical situation will be introduced, followed by explanations on Hall-based magnetic torque sensing module in terms of operation principles. Then new design of the torque module will be proposed. Next, a detailed magnetic analysis will be shown. Based on this analysis, this paper will present the simulation results. Copyright © 2015 SAE International.

Zhang J.,University of Wisconsin - Madison | Zhang X.,University of Wisconsin - Madison | Wu G.,UESTC
Proceedings - IEEE INFOCOM | Year: 2015

Visible Light Communications (VLC) is emerging as an appealing technology to complement WiFi in indoor environments. Yet maintaining VLC performance under link dynamics remains a challenging problem. In this paper, we build a VLC software-radio testbed and examine VLC channel dynamics through comprehensive measurement. We find minor device movement or orientation change can cause the VLC link SNR to vary by tens of dB even within one packet duration, which renders existing WiFi rate adaptation protocols ineffective. We thus propose a new mechanism, DLit, that leverages two unique properties of VLC links (predictability and full-duplex) to realize fine-grained, in-frame rate adaptation. Our prototype implementation and experiments demonstrate that DLit achieves near-optimal performance for mobile VLC usage cases, and outperforms conventional packet-level adaptation schemes by multiple folds. © 2015 IEEE.

2012 IEEE International Workshop on Electromagnetics: Applications and Student Innovation Competition, iWEM 2012 | Year: 2012

Conference proceedings front matter may contain various advertisements, welcome messages, committee or program information, and other miscellaneous conference information. This may in some cases also include the cover art, table of contents, copyright statements, title-page or half title-pages, blank pages, venue maps or other general information relating to the conference that was part of the original conference proceedings. © 2012 IEEE.

Yun-Sheng W.,UESTC
AIAA/IEEE Digital Avionics Systems Conference - Proceedings | Year: 2012

IMA is an embedded version of a centralized time-shared 'mainframe', which provides: shared high performance common computing resources, high speed communication network, open architecture for both software and hardware. © 2012 IEEE.

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