The F5 criterion revised

The purpose of this work is to generalize part of the theory behind Faugère’s “F5” algorithm. This is one of the fastest known algorithms to compute a Gröbner basis of a polynomial ideal I generated by polynomials f₁,…,f_m. A major reason for this is what Faugère called the algorithm’s “new” criterion, and we call “the F5 criterion”; it provides a sufficient condition for a set of polynomials G to be a Gröbner basis. However, the F5 algorithm is difficult to grasp, and there are unresolved questions regarding its termination.This paper introduces some new concepts that place the criterion in a more general setting: S-Gröbner bases and primitive S-irreducible polynomials. We use these to propose a new, simple algorithm based on a revised F5 criterion. The new concepts also enable us to remove various restrictions, such as proving termination without the requirement that f₁,…,f_m be a regular sequence.     

Termination of the F5 algorithm

The F5 algorithm, which calculates the Gröbner basis of an ideal generated by homogeneous polynomials, was proposed by Faugère in 2002; simultaneously, the correctness of this algorithm was proved under the condition of termination. However, termination itself was demonstrated only for a regular sequence of polynomials. In this paper, it is proved that the algorithm terminates for any input data. First, it is shown that if the algorithm does not terminate, it eventually generates two polynomials where the first is a reductor for the second. However, it is not argued that such a reduction is permitted by all the criteria introduced in F5. Next, it is shown that if such a pair exists, then there exists another pair for which the reduction is permitted by all the criteria, which is impossible.     

F5的FIREPASS在保险公司的应用

一、客户简介中国XX资产管理有限公司是经国务院同意,中国保险监督管理委员会批准,由中国XX保险(集团)公司和中国XX保险股份有限公司共同出资设立。公司于2003年11月23日注册成立,2004年6月28日正式揭牌。它的成立全面开启了我国保险资产管理集中专业化运作的崭新历程,标志着中国XX在建立保险业、金融服务业、保险关联产业三大产业集群的过程中迈出了重要一步。公司的经营范围为:管理运用人民币和外币自有资金及保险资金,受托或委托人民币和外币保险资金管理业务,与保险资金管理业务相关的咨询业务,国家法律法规允许的其他资产管理业务…     

丽讯D5投影机开启3D娱乐

2010年伊始,3D作为投影领域最新的热点显得异常火爆,从刚刚落下帷幕的CES大展、到全球票房突破10亿美元的科幻巨制《阿凡达》,3D技术从未像今天这样吸引如此多的目光。有业内人士认为,3D影像这一潜力巨大的新市场将在2010年被唤醒。     

丽讯D5投影机开启3D娱乐

2010年伊始，3D作为投影领域最新的热点显得异常火爆，从刚刚落下帷幕的CES大展、钊全球票房突破10亿美元的科幻巨制《阿凡达》，3D技术从未像今天这样吸引如此多的目光。有业内人上认为，3D影像这一潜力巨大的新市场将在2010年被唤醒。     

针对F5算法的盲检测隐写分析

通常基于统计特征的隐写分析算法特征针对性强,而通用隐写分析算法适应性强.结合两者的优点,提出了一种针对F5数字隐写技术的盲检测算法.根据F5算法对载体图像统计特性带来的影响,提取了21个特征.在分类器设计方面,选用了对样本数量和质量依赖性小的支持向量机.最后对不同训练样本下算法的识别能力进行了实验仿真.实验结果表明,使用高嵌入率载密图像进行训练能达到很好的检测效果,在虚警率为4%的条件下,对25%载密图像的检测结果都达到了95%以上.     

针对F5隐写分析算法的FPGA实现

应用密钥来控制隐藏路径已成为一种趋势,随着消息长度的增加和密钥空间的增大,纯软件方式已不能满足隐写分析的实时性要求。针对依赖密钥的隐写算法F5,提出一种基于现场可编程门阵列(FPGA)的隐写分析方案。正确密钥与错误密钥产生嵌入位置的样本分布具有明显的差异,利用这一特性可以得到F5的正确密钥,从而实现密钥攻击。实验表明,消息长度超过2 000 bit时,该方案和软件攻击相比时间上能降低一个数量级。     

F5C: A variant of Faugère’s F5 algorithm with reduced Gröbner bases

The F5 algorithm for computing Gröbner bases achieves a high level of efficiency through the careful analysis of signatures assigned to each computed polynomial. However, it computes and uses many polynomials that turn out to be redundant. Eliminating these redundant polynomials is a non-trivial task, because they correspond to signatures required for reduction. This paper revisits the theory underlying F5 and describes F5C, a new variant that prunes redundant polynomials, then re-computes signatures to preserve correctness. This strategy successfully reduces both overhead and execution time.     

多巴胺D1和D5受体的同源模建研究

多巴胺与其受体组成的多巴胺系统与许多疾病有关,比如帕金森病、精神分裂症等.但是,多巴胺受体的晶体结构一直没有得到解析,给相关疾病的药物开发带来难度.本文采用同源模建的方法,用与D1和D5受体同源性达到34.6%的肾上腺素能受体2vt4作为模板,构建D1和D5受体的三维模型.结果表明:经过优化和动力学模拟,然后用PROCHECK、ERRAT及PROSA程序进行构象和能量的评价,用多巴胺进行对接验证,证明模建的D1受体和D5受体模型是合理的、可靠的.     

F5隐写算法及其隐写分析研究

图像隐写分析是检测、提取和破坏隐写图像中秘密信息的技术,是信息安全领域的研究热点之一.由Westfeld提出的F5隐写算法是一种重要的图像隐写算法.分析了F5隐写算法及其隐写系统,讨论了一种针对F5隐写算法的隐藏检测方法,并给出了具体实现的算法.实验结果表明,F5算法采用矩阵编码,提高了嵌入效率.     

丽讯D5系列商务短焦

“显示大家”丽讯推出9款D5系列新品，配备了3D功能的D5系列产品引人注目。     

丽讯D5系列商务短焦

"显示大家"丽讯推出9款D5系列新品,配备了3D功能的D5系列产品引人注目。定位全面各不同D5系列机型定位商用,提供了从低端到中高端,从普屏到宽屏,从标准焦距到短焦的全方位解决方案。D5系列产品     

5G全双工D2D通信系统中的最优功率控制方案

作为5G的关键技术,设备直通技术(Device-to-Device Communication,D2D通信)和全双工可以提升5G系统的频谱效益和吞吐量,两者结合可以进一步提升性能增益。但是全双工节点的自干扰和资源复用产生的同频干扰会很大程度影响系统的性能。基于此提出了功率控制方案,通过凸规划的拉格朗日对偶方法得到最优的发射功率,来最大化全双工D2D的链路速率并同时满足蜂窝用户的服务质量(quality-of-service,QoS)需求。通过仿真,观察了相比于半双工D2D,全双工D2D的增益随着蜂窝用户的需求和自干扰消除量变化的影响,并且对比了全双工D2D复用不同数目信道时的性能。     

基于冗余零系数消除的F5改进算法

F5隐写分析算法利用收缩现象,比较剪裁后图像直方图和估计载体图像直方图的差异进行检测。针对该算法的特点,提出改进的F5算法,通过部分消除冗余零系数,提高嵌入率、防止收缩现象的发生。在标准图像集上的实验结果表明,改进算法改善了含密直方图的收缩现象,各检测参数与原始载体图像差别较小,可以有效抵抗F5隐写分析算法。     

一种基于量化表修改的F5隐写方法

IQTM-F5方法在高嵌入比情况下,DCT系数直方图统计特性会被破坏。针对该问题,利用新的信息嵌入策略并结合IQTM-F5方法中采用的修改后量化表,提出一种保持DCT系数直方图统计特性的F5隐写方法。实验结果表明,该方法能够取得与IQTM-F5方法近似的信息隐藏容量和嵌入效率,隐秘图像具有更高的图像质量,并且抗直方图统计分析攻击的能力更强。     

工业5G的D2D多跳中继辅助传输方法及中断性能分析

面向工业5G网络的超可靠强实时传输要求,研究基于设备到设备通信（device-to-device,D2D）的多跳多中继辅助传输方法。基于随机几何理论,采用泊松点过程对工业现场设备进行建模,并划分中继选择区域。多跳中继过程中,每一跳中继选择信干噪比最大的节点进行解码转发,充分考虑层叠部署的多条D2D传输路径上的节点干扰以及随机噪声,推导出端到端中断概率的闭式表达式。仿真分析了中继节点部署密度、发射功率、路径距离等因素对端到端中断概率的影响。结果表明,采用多跳多中继辅助的D2D传输可以大幅降低工业5G网络的端到端中断概率,提高传输可靠性。     

毫米波5G网络中一种D2D通信的资源分配方案

在5G系统中,毫米波（mmWave）与终端直通技术（device-to-device,D2D）有利于提升系统容量和频谱利用率。针对73 GHz下underlay蜂窝网络中的D2D资源分配进行了研究。为了降低彼此间的干扰,首先提出对基站和D2D用户接收机进行区域限制;其次利用线性相关的方法选出可复用的蜂窝用户;最后在满足蜂窝通信和D2D通信服务质量（QoS）的要求下提出一种基于干扰控制的资源分配,以提升系统的吞吐量。仿真结果表明所提算法的性能优于参考算法。该算法能够有效提升系统吞吐量和频谱效率。     

Gray-Hole Attack Minimization in IoMT with 5G Based D2D Networks

Reliable transmission is vital to the success of the next generation of communications technologies and Fifth Generation (5G) networks. Many sensitive applications, such as eHealth and medical services, can benefit from a 5G network. The Internet of Medical Things (IoMT) is a new field that fosters the maintenance of trust among various IoMT Device to Device (D2D) modern technologies. In IoMT the medical devices have to be connected through a wireless network and constantly needs to be self-configured to provide consistent and efficient data transmission. The medical devices need to be connected with sophisticated protocols and architecture to handle the synergy of the monitoring devices. Today, one of the commonly used algorithms in D2D communication is the Optimized Link State Routing protocol (OLSR). The OLSR is considerably good at effectively utilizing the bandwidth and reserving the paths. One of the major attack against the OLSR is the Node isolation attack, also known as the Gray hole denial of service attack. The Gray hole attack exploits the vulnerabilities present with sharing the topological information of the network. The attackers may use this topological information to maliciously disconnect the target nodes from the existing network and stops rendering the communication services to the victim node. Hence, considering the sensitivity and security concerns of the data used in e-Health applications, these types of attacks must be detected and disabled proactively. In this work, a novel Node Authentication (NA) with OLSR is proposed. The simulation experiments illustrated that the proposed protocol has an excellent Packet Delivery Ratio, minimal End-End delay, and minimal Packet loss when compared to the Ad-hoc On-Demand Distance Victor (AODV) protocol and the proposed authentication scheme was able to protect the OLSR protocol from a node isolation attack.