短群签名的高效批验证

进入普适通信的时代,从车辆到心脏监听器等大量设备都需要与它们的环境彼此交流信息,从而对验证和安全通信的要求不断上升：①密码费用较低;②能够快速验证大量不同来源的消息;③隐私保护。文章针对一个高效的短群签名体制提出了一个批验证算法,其中验证运算的主要部分只需要2个双线性对,就可满足上面的全部3个要求。     

一种基于数字签名的SSL协议改进策略

针对SSL协议在电子商务应用中存在的身份认证缺陷,提出了一种基于数字签名的SSL协议改进策略,并通过实验证明改进策略的可行性。具体实现上是对SSL协议本身进行改进,增加了对消息的数字签名功能,达到了防抵赖目的,克服了SSL协议的身份认证缺陷。     

无证书部分盲签名

将部分盲签名和无证书密码体制结合,首次提出了无证书部分盲签名,给出了算法模型,提出了一个具体的方案并对其安全性进行了证明。分析表明,该方案安全性好、效率高。     

New variance expressions for systematic sampling: the filtering approach

We present a collection of variance models for estimators obtained by geometric systematic sampling with test points, quadrats, and n‐boxes in general, on a bounded domain in n‐dimensional Euclidean space ?ⁿ, n = 1, 2, ... , and for systematic rays and sectors on the circle. The approach adopted ? termed the filtering approach ? is new and different from the current transitive approach. This report is only preliminary, however, because it includes only variance models in terms of the covariogram of the measurement function. The estimation step is in preparation.     

Distributed finite-time tracking for a team of planar flexible spacecraft

The paper presents a distributed finite-time controller for multiple under-actuated spacecraft with flexible appendages to track a virtual leader with stationary states under an undirected communication graph. Each spacecraft of concern is simplified as a free-floating hub-beam system, which is an under-actuated Euler-Lagrange system by nature since only the hub is driven. In the undirected communication graph, it is assumed that only one spacecraft can receive the information from the virtual leader. A distributed finite-time control law is presented for such a multi-agent system. The closed-loop system is proven to converge to the desired states within a finite time via Lyapunov theory and homogeneous method. Finally, a comparison is made between the proposed controller and the PD controller to show the better performance of the proposed controller.     

关于底部两层框架抗震墙砖房设计启示

文章通过某工程实例,主要围绕改善底层矮钢筋混凝土墙的抗震性能,增强过渡楼层和这类房屋的整体抗震能力,并通过模型试验研究分析该工程的设防要求。     

非侵入式电力负荷多目标分解框架

现有基于最优化的非侵入式负荷分解方法存在两个问题:使用一到两个特征对家庭负荷的分解效果差;而使用三个及以上特征作为用电设备辨识的目标函数难度高。提出非侵入式电力负荷多目标分解框架,解决传统方法利用特征数少、加权系数难确定等问题。以有功功率、无功功率、视在功率、谐波和电流波形作为电器运行状态的目标函数,建立多目标优化负荷分解模型。利用多目标进化算法(Multi-Objective Evolutionary Algorithm,MOEA)对实测用电数据进行负荷分解求得Pareto最优解集。最后通过多准则决策方法选出识别结果。实验结果表明,增加特征可提高MOEA算法对多个用电设备同时运行时识别准确率,且与当前主流算法相比,所提框架对家庭负荷分解的准确率更高。     

群的置换表示与群的图表示

考虑群Ｇ在一个集合Ω上传递转换作用和把Ω做成Ｇ的Ｃ［Ω］模空间,得到Ｇ作为线性群在Ｃ［Ω］作用,那么二者有怎样的内在联系呢？本文主要结果是：群Ｇ在一个基数为ｐ的集合Ω上的作用是传递的,那么这个置换特征标π有如下分解式：⑴若Ｇ在Ω上的作用是二传递的,则π＝１Ｇ＋χｉ,ｄｅｇχ＝ｐ－１;⑵若Ｇ在Ω上的作用是单本原的,则π＝１Ｇ＋∑ｒｉ＝１χｉ,ｄｅｇχｉ＝ｍ,ｉ＝１,２,…,ｒ,ｐ－１＝ｍ·ｒ．此处数ｒ称为Ｇ的秩．     

Parathyroid Tumors: Molecular Signatures

Parathyroid tumors are rare endocrine neoplasms affecting 0.1–0.3% of the general population, including benign parathyroid adenomas (PAs; about 98% of cases), intermediate atypical parathyroid adenomas (aPAs; 1.2–1.3% of cases) and malignant metastatic parathyroid carcinomas (PCs; less than 1% of cases). These tumors are characterized by a variable spectrum of clinical phenotypes and an elevated cellular, histological and molecular heterogeneity that make it difficult to pre-operatively distinguish PAs, aPAs and PCs. Thorough knowledge of genetic, epigenetic, and molecular signatures, which characterize different parathyroid tumor subtypes and drive different tumorigeneses, is a key step to identify potential diagnostic biomarkers able to distinguish among different parathyroid neoplastic types, as well as provide novel therapeutic targets and strategies for these rare neoplasms, which are still a clinical and therapeutic challenge. Here, we review the current knowledge on gene mutations and epigenetic changes that have been associated with the development of different clinical types of parathyroid tumors, both in familial and sporadic forms of these endocrine neoplasms.     

Integration of Mutational Signature Analysis with 3D Chromatin Data Unveils Differential AID-Related Mutagenesis in Indolent Lymphomas

Activation-induced deaminase (AID) is required for somatic hypermutation in immunoglobulin genes, but also induces off-target mutations. Follicular lymphoma (FL) and chronic lymphocytic leukemia (CLL), the most frequent types of indolent B-cell tumors, are exposed to AID activity during lymphomagenesis. We designed a workflow integrating de novo mutational signatures extraction and fitting of COSMIC (Catalogue Of Somatic Mutations In Cancer) signatures, with tridimensional chromatin conformation data (Hi-C). We applied the workflow to exome sequencing data from lymphoma samples. In 33 FL and 30 CLL samples, 42% and 34% of the contextual mutations could be traced to a known AID motif. We demonstrate that both CLL and FL share mutational processes dominated by spontaneous deamination, failures in DNA repair, and AID activity. The processes had equiproportional distribution across active and nonactive chromatin compartments in CLL. In contrast, canonical AID activity and failures in DNA repair pathways in FL were significantly higher within the active chromatin compartment. Analysis of DNA repair genes revealed a higher prevalence of base excision repair gene mutations (p = 0.02) in FL than CLL. These data indicate that AID activity drives the genetic landscapes of FL and CLL. However, the final result of AID-induced mutagenesis differs between these lymphomas depending on chromatin compartmentalization and mutations in DNA repair pathways.