基于SFN-SD的北极冰区船舶航行风险传递路径研究

为明晰北极冰区船舶航行风险传递路径,从人员、船舶、环境、管理4方面识别北极冰区航行风险因素,并应用空间故障网络(SFN)理论和决策试验与评估实验室(DEMATEL)方法,分析船舶北极航行风险事件;采用主观数据获得风险传递概率和传递路径,构建北极冰区船舶航行风险传递网络模型;基于永盛轮北极航行记录数据,运用系统动力学(SD)方法,仿真并验证北极冰区船舶航行风险传递网络模型。结果表明:船舶北极航行风险事件中,8种为边缘事件,14种为过程事件,8种为最终事件;从边缘事件到最终事件有15条网络传递路径;经实例验证,所构建的风险传递网络模型可靠;通过该模型能够描述风险事件的传递效应和传递路径,获得最终风险事件的动态概率曲线,揭示北极冰区船舶航行风险传递的规律,为风险防范措施的制定提供技术支持。

On the Performance of Active Analog Self-Interference Cancellation Techniques for Beyond 5G Systems

The in-band full-duplex(IBFD)mechanism is of interest in beyond 5 G systems due to its potential to enhance spectral efficiency and reduce delay.To achieve the maximum gain of IBFD systems,the significant self-interference(SI)must be efficiently suppressed.The challenges of wideband selfinterference cancellation(SIC)lie in the radio frequency(RF)domain,where the performance will be limited by the hardware.This paper reviews current RF cancellation mechanisms and investigates an efficient mechanism for future wideband systems with minimum complexity.The working principle and implementation details of multi-tap cancellers are first introduced,then an optical domain-based RF canceller is reviewed,and a novel low-cost design is proposed.To minimize the cost and complexity of the canceller,the minimum required number of taps are analyzed.Simulation results show that with the commonly used 12-bits analog-to-digital converter(ADC)at the receiver,the novel optical domain-based canceller can enable efficient SIC in the 3 GPP LTE specifications compatible system within 400 MHz bandwidth.

Robust Digital Non-Linear Self-Interference Cancellation in Full Duplex Radios with Maximum Correntropy Criterion

Full duplex radio increases the frequency efficiency but its performance is limited by the self-interference （SI）. We first analyze the multiple noises in the full duplex radio system and model such noises as an α - stable distribution. Then we formulate a novel non-Gaussian SI problem. Under the maximum correntropy criterion （MCC）, a robust digital non-linear self-interference cancellation algorithm is proposed for the SI channel estimation. A gradient descent based algorithm is derived to search the optimal solution. Simulation results show that the proposed algorithm can achieve a smaller estimation error and a higher pseudo signal to interference plus noise ratio （PSINR） than the well-known least mean square （LMS） algorithm and least square （LS） algorithm.

Self-Interference Elimination by Physical Feedback Channel in CCFD for 3-D Beamforming Communication

The 3-D beamforming scheme has elite as evolving interest because of its efficiency to empower assorted techniques such as vertical and horizontal domains and emanation beamforming according to subscriber's provisions. Usually, 3-D beamforming communication is set up on FDD/TDD approach those effects on the performance of spectrum and energy efficiency. Co-frequency and CoTime Full Duplex(CCFD) is an effective solution to improve the spectrum and energy efficiency by transmitting and receiving simultaneously in frequency and time domain. While, CCFD communication often face the self-interference issue when communication occurs, simultaneously. Consequently, in this paper a self-interference elimination by physical feedback channel in CCFD for 3-D Beamforming communication scheme is proposed to improve the over-all system performance in terms of energy and spectrum efficiency. The simulation and analytical outcomes demonstrated that the proposed system is superior than the traditional one.

Adaptive digital self-interference cancellation based on fractional order LMS in LFMCW radar

Adaptive digital self-interference cancellation(ADSIC)is a significant method to suppress self-interference and improve the performance of the linear frequency modulated continuous wave(LFMCW)radar.Due to efficient implementation structure,the conventional method based on least mean square(LMS)is widely used,but its performance is not sufficient for LFMCW radar.To achieve a better self-interference cancellation(SIC)result and more optimal radar performance,we present an ADSIC method based on fractional order LMS(FOLMS),which utilizes the multi-path cancellation structure and adaptively updates the weight coefficients of the cancellation system.First,we derive the iterative expression of the weight coefficients by using the fractional order derivative and short-term memory principle.Then,to solve the problem that it is difficult to select the parameters of the proposed method due to the non-stationary characteristics of radar transmitted signals,we construct the performance evaluation model of LFMCW radar,and analyze the relationship between the mean square deviation and the parameters of FOLMS.Finally,the theoretical analysis and simulation results show that the proposed method has a better SIC performance than the conventional methods.

Polarization Oblique Projection Based Self-Interference Cancellation against PA Nonlinear Distortion in MIMO Full Duplex System

In MIMO full duplex system,power amplifier(PA) nonlinearity limits the self-interference(SI) cancellation seriously. Most existing methods need to model and estimate the PA nonlinearity in order to reconstruct the SI,however the estimation error caused by the mismatch between the estimated PA model and the actual PA property still impacts the cancellation ability,especially when the transmit power is high. In this paper we propose a polarization oblique projection based self-interference cancellation method which does not need to estimate the PA nonlinearity coefficients. It exploits the polarization state information of the signals which is immune to the PA nonlinearity,and establishes an oblique projection operator to cancel the SI. Numerical results and analysis demonstrate that it can cancel the nonlinear SI effectively. Moreover the signal to interfere plus noise ratio(SINR) and the achievable sum rate do not deteriorate when the transmit power is high. Further,the upper bound of the achievable sum rate can be more than twice that of the half duplex.

阿瑞匹坦抑制SFN蛋白对非小细胞肺癌细胞上皮间质转化机制研究

目的研究分层蛋白Stratifin(SFN)对非小细胞肺癌A549细胞上皮间质转化(EMT)和迁移、侵袭的调控作用,以及阿瑞匹坦对SFN功能的影响。方法通过瞬时转染技术将siSFN-1、siSFN-2、SFN、NC基因转入A549细胞中,Western blot实验检测SFN、E-钙黏蛋白、N-钙黏蛋白以及波形蛋白表达水平,细胞划痕实验和Transwell实验检测细胞迁移、侵袭作用;通过CCK8实验检测阿瑞匹坦对过表达SFN的A549细胞在24、48、72 h增殖的调控能力;根据CCK8测得的药物IC 50值进一步探索阿瑞匹坦不同浓度(16、8、4μmol/L)作用于过表达SFN的A549细胞48 h后的SFN、E-钙黏蛋白、N-钙黏蛋白、波形蛋白的表达以及细胞迁移、侵袭的变化。结果24、48、72 h的细胞增殖-毒性实验中,随着阿瑞匹坦作用于细胞的时间不断延长,细胞增殖能力也随之出现逐渐下降趋势,药物抑制作用显著(P<0.05)。划痕实验结果表明转染SFN基因的A549细胞迁移距离明显高于NC、siSFN-1、siSFN-2组(P<0.05)。安慰剂组的迁移距离较16、8、4μmol/L阿瑞匹坦组迁移距离长;并且在16、8、4μmol/L瑞匹坦组中,细胞迁移距离随浓度降低逐渐加长(P<0.05)。Transwell迁移和侵袭实验中转染SFN的A549细胞迁移和侵袭的细胞数量多于NC、siSFN-1、siSFN-2组(P<0.05)。安慰剂处理组的细胞迁移和侵袭数量较16、8、4μmol/L阿瑞匹坦组多;并且在16、8、4μmol/L瑞匹坦组中,细胞迁移和侵袭的数量随着阿瑞匹坦浓度降低逐渐增多(P<0.05)。Western blot分析显示过表达SFN促使上皮标志物E-钙黏蛋白减少,间质标志物N-钙黏蛋白和波形蛋白增加(P<0.05)。安慰剂组E-钙黏蛋白较不同浓度阿瑞匹坦组减少,N-钙黏蛋白和波形蛋白较不同浓度阿瑞匹坦组明显增多;阿瑞匹坦组中随浓度增高E-钙黏蛋白增多,N-钙黏蛋白减少(P<0.05)。结论过表达SFN能够促进非小细胞肺癌的上皮间质转化和迁移、侵袭,而阿瑞匹坦可以通过抑制SFN表达进而抑制其介导的上皮间质转化和迁移、侵袭。

A physical layer security scheme for full-duplex communication systems with residual self-interference and non-eavesdropping CSI

We discuss the physical layer security scheme in the Full-Duplex(FD)MIMO point-to-point two-way communication system with residual self-interference,in which legitimate nodes send confidential information and null space Artificial Noise(AN)while receiving information.Because the Channel State Information(CSI)of the eavesdropper is unavailable,we optimize the covariance matrices of the information signal as well as the allocation of the antenna for transmitting and receiving to minimize the signal power consumption under the target rate constraint.As a result,the power of AN is maximized within the limit of total power,so the interception capability of the eavesdropper is suppressed as much as possible.Since self-interference cannot be completely eliminated,the optimization process of one legitimate node depends on the optimization result of the other.By substituting self-interference power in the secrecy rate formula with its average value,the joint optimization process at the two nodes is transformed into two separate and solvable optimization processes.Then,the Water-Filling Algorithm(WFA)and bisection algorithm are used to get the optimal covariance matrices of the signal.Furthermore,we derive the theoretical lower bound of ergodic achievable secrecy rate under rayleigh channels to evaluate the performance of the scheme.The simulation results show that the theoretical derivation is correct,and the actual achievable rate is very close to the target rate,which means that the approximation in the optimization is feasible.The results also show that secrecy transmission can be realized because a considerable secrecy rate can be achieved.

All-Digital Self-Interference Cancellation in Zero-IF Full-Duplex Transceivers

In this paper,a general scheme in digital self-interference cancellation at baseband for zero-IF full-duplex transceivers is presented. We model the self-interference signals specifically with only the nonlinear distortion signals falling in receiving band considered. A joint estimation algorithm is proposed for compensating the time delay and frequency offset taking into account the IQ amplitude and phase imbalances from mixers. The memory effect and nonlinear distortion are adaptively estimated by the de-correlated normalized least mean square(DNLMS) algorithm. Numerical simulation results demonstrate that the proposed self-interference cancellation scheme can efficiently compensate the self-interference and outperform the existing traditional solutions.

一种基于话务模型变化精准实现SFN动态部署提升网络效能方法研究

以改善4G用户体验速率为导向,以网格吞吐率模型为依据,当用户数增加不能够带来吞吐率增加为拐点,就需要考虑拆分SFN小区为独立RRU小区。反之,当独立小区的用户数少、吞吐率低、干扰严重、频繁切换时,需要考虑将独立RRU小区组合成为SFN小区,制定动态SFN组合与拆分评估策略,将人工的这种优化转化为自动的优化,节省运维成本。

CoMP系统的SFN预编码改进算法

为提高LTE-Advanced系统小区边缘用户的吞吐量和用户体验,在现有协作多点传输(Coordinated Multi-Point,CoMP)方案基础上提出了两种CoMP系统的单频网(Sin-gle Frequency Network,SFN)预编码改进算法,以改善传统SFN预编码中信道合并的不确定性问题.第一种改进算法在发射端的部分传输节点处引入一个便于信道合并的相位参数,并按照合并后信道增益最大的准则确定相位参数的取值;第二种改进算法令部分传输节点的发射数据映射到天线时进行交换操作,同样按照信道增益最大准则确定交换方式.仿真结果表明,两种改进算法能有效提高小区边缘用户的谱效率,且能适用于相干/非相干信道及低/高秩信道的情况.

CMMB超理论间距SFN设计的研究——CMMB下一阶段建网策略探讨

针对CMMB常规单频网组网所存在的一些突出问题,提出CMMB超理论间距单频网以及CMMB HSFN这两种组网策略。在对常规单频网分析的基础上,总结出CMMB超理论间距单频网设计的理论基础,并认为延时与同频干扰比(CIR)是设计这种单频网时需重点考虑的两个因素,进而对CMMB单频网进行超理论间距组网的可行性与工程设计、CMMB HSFN组网等进行了探讨。

萝卜硫素抗癌作用研究进展

癌症是威胁人类健康的头号杀手,其致死率占所有疾病之首。目前,治疗癌症的方式不可避免地存在相关副作用,因此开发安全、有效的抗癌药物成为人们关注的焦点。萝卜硫素作为十字花科植物中生物活性高的天然化合物之一,具有抗癌、抗氧化、抗病毒等特性,其中,治疗癌症的作用机理被人们广泛研究。萝卜硫素可以通过调控细胞周期、抑制细胞的迁移和侵袭以及抑制凋亡相关蛋白的表达从而抑制癌细胞的生长,也可以通过抗炎和抗氧化,抑制癌细胞的发生和发展。与传统治疗癌症的方法相比,萝卜硫素具有安全、易获得的特点,在抗癌方面有较大的发展潜力。本文综述了近两年萝卜硫素抗癌作用机制,为萝卜硫素的抗癌作用的进一步研究提供了相应的理论依据。

Optical multipath self-interference cancellation for a wideband in-band full-duplex system using a silicon photonic modulator chip

We propose and experimentally demonstrate a photonic method for wideband multipath self-interference cancellation using a silicon photonic modulator chip.The chip generates phase-inverted reference signals by leveraging the opposite phase between optical sidebands.Effectively managing amplitude and phase imbalances between self-interference and reference signals,the approach rectifies discrepancies through consistent chip manufacturing and packaging processes.Employing photonic multi-dimensional multiplexing,including wavelength and polarization,enables the acquisition of multiple reference signals.Experimental results show multipath cancellation depths of 25.53 dB and 23.81 dB for bandwidths of 500 MHz and 1 GHz,achieved by superimposing 2-path reference signals.

地面数字电视广播单频网(SFN)组网关键技术与测试方法

数字电视是电视信号数字化后的产物,分为有线传输数字电视、卫星传输数字电视、地面无线传输数字电视。地面无线传输数字电视作为电视广播的传统手段,具有简单接收和移动接收的能力,能够满足现代信息化社会"信息到人"的基本需求。数字电视地面广播的传输和使用能克服恶劣环境的影响,从根本上解决了频谱资源紧张的问题,所以数字电视地面广播的推广和产业化将带来不可估量的经济增长。作为地面数字电视广播系统重要组网方式之一的单频网必将随着地面数字电视的发展而迎来高速发展的时期,而国标(DTMB标准)地面数字电视单频网也必将随着DTMB标准的推广及国际化而被更多的国家和地区所采纳,其推广前景广阔。主要阐述地面数字电视广播单频网的组网方式、关键技术与指标、测试方法。

Spatiotemporal dynamics of vegetation response to permafrost degradation in Northeast China

Permafrost in Northeast China is undergoing extensive and rapid degradation,and it is of great importance to understand the dynamics of vegetation response to permafrost degradation during different periods in this region.Based on the meteorological station data and MODIS land surface temperature data,we mapped the distribution of permafrost using the surface frost number(SFN)model to analyze the permafrost degradation processes in Northeast China from 1981 to 2020.We investigated the spatiotemporal variation characteristics of vegetation and its response to permafrost degradation during different periods from 1982 to 2020 using the normalized difference vegetation index(NDVI).We further discussed the dominant factors influencing the vegetation dynamics in the permafrost degradation processes.Results indicated that the permafrost area in Northeast China decreased significantly by 1.01×10^(5) km^(2) in the past 40 a.The permafrost stability continued to weaken,with large areas of stable permafrost(SP)converted to semi-stable permafrost(SSP)and unstable permafrost(UP)after 2000.From 1982 to 2020,NDVI exhibited a significant decreasing trend in the seasonal frost(SF)region,while it exhibited an increasing trend in the permafrost region.NDVI in the UP and SSP regions changed from a significant increasing trend before 2000 to a nonsignificant decreasing trend after 2000.In 78.63%of the permafrost region,there was a negative correlation between the SFN and NDVI from 1982 to 2020.In the SP and SSP regions,the correlation between the SFN and NDVI was predominantly negative,while in the UP region,it was predominantly positive.Temperature was the dominant factor influencing the NDVI variations in the permafrost region from 1982 to 2020,and the impact of precipitation on NDVI variations increased after 2000.The findings elucidate the complex dynamics of vegetation in the permafrost region of Northeast China and provide deeper insights into the response mechanisms of vegetation in cold regions to permafrost degradation induced by climate change.

PT5779 SFN适配器在地面数字电视广播单频网中的应用

本文对地面数字电视广播单频网的技术要求、规划实施作了简单介绍,并进一步对单频网同步的基本原理、PT5779SFN适配器的主要功能、实际应用经验等作了详细介绍。

700兆赫频率迁移项目单频网组网验证和组网失败案例分析

全国地面数字电视700兆赫频率迁移工作已经基本完成,地面数字电视可用频率资源紧缺,组建地面数字电视单频网成为解决该问题的最佳方案。如何确保地面数字电视单频网成功组网以及稳定运行成为地面数字电视系统运行和维护的重要工作。本文通过分析在700兆赫频率迁移项目单频网验收测试工作中遇到的实际案例,发现了单频网组网在实际操作中可能出现的问题,给出了排查单频网组网失败问题的具体方法,并总结了消除单频网干扰的工作流程,为地面数字电视单频网运维工作提供了借鉴和参考。

细毛羊肩颈部与腹部皮肤组织SFN基因差异表达的研究

为了探讨SFN基因对细毛羊羊毛生长发育的影响,试验采用基因芯片、荧光定量PCR、蛋白质质谱等技术,对SFN基因在敖汉细毛羊肩颈部(多毛部位)和腹部(少毛部位)皮肤的mRNA表达水平和蛋白质表达水平进行了研究。结果表明:细毛羊肩颈部与腹部均检测到了SFN基因的mRNA与蛋白质表达,且肩颈部表达水平均高于腹部。基因芯片研究显示,SFN基因肩颈部mRNA表达水平是腹部的1.23倍;荧光定量PCR结果显示,肩颈部mRNA表达水平分别是腹部的2.340 26,1.594 75,2.954 10,1.981 67倍,且表达趋势与芯片结果一致;肩颈部SFN基因蛋白质的表达量是腹部的2.83倍。

SFN碘联雾化镀膜显现光滑客体水渍足迹

在勘查现场,刑事技术人员经常会遇到光滑地面上已干涸的泥水足迹,如果水渍足迹时间较短,由于未完全干涸,可以使用吹粉方法,然后使用胶带较容易提取下来;如果气温高、时间长,足迹会牢固地与地面结合在一起,很难用胶带粘下来,又易变形,影响足迹检验效果。介绍一种SFN熏显碘联雾化镀膜法显现光滑客体表面水渍足迹,该技术能够有效显现光滑表面水渍足迹,反差明显,容易拍照记录。