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Minimizing the risk of small-for-size syndrome after liver surgery

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Hepatobiliary & Pancreatic Diseases International 2022年第2期21卷 113-133页

作者： michail Papamichail michail Pizanias NigelD Heaton Department of Hepato-Pancreato-Biliary Surgery Royal Blackburn HospitalBlackburn BB23HHUK Department of General Surgery Whittington HospitalLondon N195NFUK Department of Liver Transplant and Hepato-Pancreato-Biliary Surgery Institute of Liver StudiesKings Health Partners at King’s College Hospital NHS TrustLondon SE59RSUK

Background: Primary and secondary liver tumors are not always amenable to resection due to location and size. Inadequate future liver remnant(FLR) may prevent patients from having a curative resection or may result in increased postoperative morbidity and mortality from complications related to small-forsize syndrome(SFSS). Data sources: This comprehensive review analyzed the principles, mechanism and risk factors associated with SFSS and presented current available options in the evaluation of FLR when planning liver surgery. In addition, it provided a detailed description of specifc modalities that can be used before, during or after surgery, in order to optimize the conditions for a safe resection and minimize the risk of SFSS. Results: Several methods which aim to reduce tumor burden, preserve healthy liver parenchyma, induce hypertrophy of FLR or prevent postoperative complications help minimize the risk of SFSS. Conclusions: With those techniques the indications of radical treatment for patients with liver tumors have signifcantly expanded. The successful outcome depends on appropriate patient selection, the individualization and modifcation of interventions and the right timing of surgery.

关键词： Small-for-size syndrome Liver resection Future liver remnant

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RIS-enhanced multi-cell downlink transmission using statistical channel state information

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Science China(Information Sciences) 2023年第11期66卷 244-259页

作者： Xiao LI Luoluo JIANG Caihong LUO yu HAN michail MATTHAIOU Shi JIN The National Communications Research Laboratory Southeast University Centre for Wireless Innovation(CWI) Queen's University Belfast

This paper considers a multi-cell downlink transmission system, where a reconfigurable intelligent surface(RIS) is deployed to support the connectivity of users in blind areas(i.e., at the cell edges). In order to reduce the instantaneous channel state information(CSI) acquisition overhead at each base station(BS),only statistical CSI is considered at both the BSs and the RIS. Particularly, each BS has only statistical CSI within its own cell. Under these assumptions, we first obtain the approximated ergodic spectral efficiency(SE) for each user. Then, we investigate the BSs beamforming and RIS phase shift joint optimization under different criteria. For the approximated ergodic weighted sum SE maximization criteria, a sub-optimal algorithm is proposed, based on complex circle manifold, to design the RIS phase shift while the statistical maximum ratio transmission beamforming is employed at each BS. To ensure fairness, we adopt the projected subgradient-based algorithm in order to optimize the approximated minimum ergodic user SE. Simulation results demonstrate that the approximated ergodic SE expression matches well with the exact expression,whilst the superiority of the weighted sum SE and fairness performance of the proposed algorithms are verified.

关键词： multi-cell RIS statistical CSI fairness transmission weighted sum spectral efficiency maximization

CSI acquisition in RIS-assisted mobile communication systems

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National Science Review 2023年第8期10卷 33-47页

作者： yu Han Wankai Tang Xiao Li michail Matthaiou Shi Jin National Mobile Communications Research Laboratory Southeast University Centre for Wireless Innovation(CWI) Queen's University Belfast

Reconfigurable intelligent surface-(RIS) assisted mobile communication is a promising technological paradigm thanks to the attractive advantages of low cost and flexible control of electromagnetic ***, the low-cost features of RISs entail some fundamental challenges to the acquisition of channel state information(CSI), which is essential for the optimal RIS design. To tackle this problem, there have been extensive studies on CSI acquisition in RIS-assisted mobile communication systems, from the perspective of architectural improvement as well as specific mathematical solutions. This article aims to overview the existing works on CSI acquisition in RIS-assisted mobile communication systems.

关键词： channel estimation hybrid RIS implicit CSI RIS

Pre-processing for time domain image formation in SS-BSAR system

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Journal of Systems Engineering and Electronics 2012年第6期23卷 875-880页

作者： michail Antoniou Mikhail Cherniakov School of Electronic Electrical and Computer EngineeringUniversity of BirminghamBirmingham B15 2TTUK

A pre-processing procedure is designed for a space-surface bistatic synthetic aperture radar （SS-BSAR） system when a time domain image formation algorithm is employed. Three crucial technical issues relating to the procedure are fully discussed. Firstly, unlike image formation algorithms operating in the frequency domain, a time domain algorithm requires the accurate global navigation satellite system （GNSS） time and position. This paper proposes acquisition of this information using a time-and-spatial transfer with precise ephemeris and interpolation. Secondly, synchronization errors and compensation methods in SS-BSAR are analyzed. Finally, taking the non-ideal factors in the echo and the compatibility of image formation algorithms into account, a matched filter based on the minimum delay is constructed. Experimental result using real data suggest the pre-processing is functioning properly.

关键词： image formation space-surface bistatic syntheticaperture radar (SS-BSAR) global navigation satellite system(GNSS) synchronization range compression.

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Passive GNSS-based SAR imaging and opportunities using Galileo E5 signals

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Science China(Information Sciences) 2015年第6期58卷 84-94页

作者： MA Hui ANTONIOU michail CHERNIAKOV Mikhail School of Electronic and Information Engineering Beihang University Electronic Electrical and Systems Engineering Department University of Birmingham

This paper investigates the feasibility of Galileo navigation satellites as transmitters of opportunity in passive bistatic synthetic aperture radar(SAR) systems from the perspectives of signal processing and experiment program. Experimental images obtained using a single Galileo channel, E5 a or E5 b, are presented and analyzed. The paper also puts forward the channel combination scheme to jointly process E5 a and E5 b channels, which brings up high-resolution possibilities for passive SAR technique. By employing the entire E5 band for imaging, the range resolution may be potentially increased by up to 5 times. Preliminary experimental results for this concept are demonstrated.

关键词： bistatic synthetic aperture radar(BSAR) GNSS-based SAR Galileo E5 channel combination

Space-surface bistatic synthetic aperture radar with navigation satellite transmissions: a review

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Science China(Information Sciences) 2015年第6期58卷 5-24页

作者： ANTONIOU michail CHERNIAKOV Mikhail MA Hui Electronic Electrical and Systems Engineering Department University of Birmingham School of Electronic and Information Engineering Beihang University

This paper reviews the theory and practice of Space-Surface Bistatic Synthetic Aperture Radar(SS-BSAR) using navigation satellites as transmitters. In recent years, this innovative technology has reached a maturity stage which allows it to be considered for a wide range of applications. The paper covers the fundamental aspects of this technology as a radar system, such as the resolution, power budget and Point Spread Function(PSF) analysis, as well as its signal processing aspects and the state of the art in terms of advanced SAR techniques that it enables. Finally, the theoretical aspects of the paper may be directly transferred to the more generic SS-BSAR concept.

关键词： bistatic synthetic aperture radar GNSS-based SAR space-surface bistatic SAR coherent change detection multi-perspective imaging

GNSS-based BiSAR imaging using modified range migration algorithm

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Science China(Information Sciences) 2015年第8期58卷 144-156页

作者： ZENG Tao LIU FeiFeng ANTONIOU michail CHERNIAKOV Mikhail Beijing Key Laboratory of Embedded Real-time Information Processing Technology Beijing Institute of Technology School of Electronic Electrical and Systems Engineering University of Birmingham

This paper proposed a new focusing approach for the bistatic SAR systems with a GNSS(Global Navigation Satellite System) satellite as the transmitter. Because of the long integration time the inherited curvature of the transmitter’s trajectory was adopted and the spatial variance of the equivalent velocity was derived under the principal of equivalent slant range model in the system signal model. The proposed focusing approach consists of two-step processing. Firstly, the general Doppler phase from constant velocity of the echo data is focused by modified Stolt mapping. Secondly, the residual nonlinear Doppler phase due to velocity variation is compensated by means of block-processing-based adaptive phase compensation to achieve large scene focusing. The simulation and experimental results validate the proposed algorithm in GNSS-based Bi SAR systems.

关键词： GNSS-based Bi SAR equivalent slant range model curvature of trajectory two-step processing modified Stolt mapping

Coexistence Between Massive MIMO and Radar Communications:Performance Analysis

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Journal of Communications and Information Networks 2023年第1期8卷 37-47页

作者： Mohamed Elfiatoure Hien Quoc Ngo michail Matthaiou Centre for Wireless Innovation(CWI) Queen’s University BelfastBelfast BT39DTUK

Frequency spectrum sharing between radar and communication systems has recently attracted substantial *** consider the coexistence between a massive multiple-input multiple-output(MIMO)downlink system and MIMO radar to enable the operation of these two systems with minimal mutual *** an asymptotic analysis,we show that by using more antennas at the base station(BS),we can improve the performance of massive MIMO,while keeping the interference to the radar system ***,if we use a large number of antennas at the BS and make the transmit power inversely proportional to the number of antennas,we can avoid the interference from the massive MIMO system to the radar system,with no compromise in the performance of the massive MIMO ***-form expressions for the probability of detection of the radar system and the downlink spectral efficiency of the massive MIMO system,are ***,we propose a power allocation scheme which selects the transmit powers at the MIMO radar and BS to maximize the probability of detection for the MIMO ***,the optimal power allocation can be determined in *** results provide valuable insights into the practical coexistence between massive MIMO and radar systems.

关键词： massive MIMO radar-communication coexistence spectrum sharing

Primary melanoma of the gallbladder: Does it exist? Report of a case and review of the literature

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World Journal of Gastroenterology 2006年第26期12卷 4259-4261页

作者： michail Safioleas Emmanouil Agapitos Konstantinos Kontzoglou michail Stamatakos Panagiotis Safioleas George Mouzopoulos Alkiviadis Kostakis Department of Propedeutic Surgery School of MedicineAthens UniversityLaiko HospitalGreece Depatment of Pathology School of MedicineAthens UniversityGreece Department of General Surgery General Hospital of SpartaGreece

With the occasion of a case of malignant melanoma of the gallbladder, which appeared to be primary, we have reviewed the literature and the result of this research was that primary melanoma of the gallbladder remains a questionable medical entity. Only few cases of both primary and metastatic gallbladder melanoma have been reported so far, and the only agreement is that surgery is the mainstaytreatment. The role of adjuvant chemotherapy, hormonotherapy or immunotherapy for both primary and metastatic disease remains undefined.

关键词： Neoplasms of the gallbladder Gallbladder Metastatic melanoma