关于中国和印度尼西亚在资源环境领域开展重点合作的建议

自2013年"一带一路"倡议首次提出到2018年的5年以来,中国和印度尼西亚的科技合作形成了一系列较为成熟的框架及协议,取得了诸多进展。"21世纪海上丝绸之路"倡议是中国加强海洋国际合作和追求互利共赢的重大顶层设计。印度尼西亚位于两大蓝色经济通道交汇之处,地理优势十分突出,该国提出的"全球海洋支点"构想是其发展重心由陆地转向海洋的关键性战略调整。中国的"21世纪海上丝绸之路"同印度尼西亚的"全球海洋支点"高度契合,两者深度对接将为两国的科技合作带来新的机遇。文章在系统梳理中国和印度尼西亚科技合作现状的基础上,重点探讨了两国加强科技合作的关键契合点,提出了海洋资源规划、产业链优化、基础设施风险防控、重大自然灾害应对等具有合作潜力的重点领域,建议基于共商、共建、共享的原则和政策导向,结合民生要求和科学目标,加快推进两国的科技合作,尤其应重点关注气候变化和自然灾害应对的合作领域。     

对称矩阵逆特征值问题的向后误差

给出了对称矩阵逆特征值问题的一个更一般的向后误差计算公式,推广了孙继广的结论,并给出一个简单的证明。     

Almost split sequences for symmetric non-semisimple Hopf algebras

INTRODUCTION Almost split sequences, also called Auslander- Reiten sequences, were discovered by Auslander et al.(1995) for finitely generated modules over a finite- dimensional (artin) algebra and play an important role in other settings as well. While the proof of the exis-tence of almost split sequences for arbitrary artin algebras (see Section 1 of Chapter V in (Auslander et al., 1995)) is fairly constructive, it is sometimes pos-sible to give other ways of constructing almost spli…     

轴对称压力容器弹塑性与强度分析

本文应用第一、第三强度理论对轴对称压力容器圆筒和半圆球部分进行弹塑性力学分析,得到各自弹性和塑性极限应力,将其与压力容器规范中径分析结果作对比分析。此外,本文还分析了径比对压力容器结构设计和强度的影响。     

局部对称空间的伪脐点子流形的内蕴刚性积分不等式

研究了局部对称空间的紧致的脐子流形，得到了这种子流形的关于截面曲率和Ricci曲率的两个内蕴积分不等式。     

Comments on ＂How to repair the Hill cipher＂

A modification of the Hill cipher algorithm was recently proposed by Ismail et al.（2006）, who claimed that their new scheme could offer more security than the original one due to an extra non-linearity layer introduced via an elaborated key generation mechanism. That mechanism produces one different encryption key for each one of the plaintext blocks. Nevertheless, we show in this paper that their method still has severe security flaws whose weaknesses are essentially the same as that already found in the original Hill cipher scheme.     

关于对称多项式的注记

本文利用排列、组合的思想解决了用待定系数法求初等对称多项式表示n元对称多项式时,计算相应的初等对称多次式口及多次式,f值难的问题．     

Comment: Comments on "How to repair the Hill cipher"

A modification of the Hill cipher algorithm was recently proposed by Ismail et al.(2006), who claimed that their new scheme could offer more security than the original one due to an extra non-linearity layer introduced via an elaborated key generation mechanism. That mechanism produces one different encryption key for each one of the plaintext blocks. Nevertheless, we show in this paper that their method still has severe security flaws whose weaknesses are essentially the same as that already found in the original Hill cipher scheme.     

关于广义对称SOR方法的收敛性

对求解对称线性鞍点问题的广义对称SOR（successive over-relaxation）方法作了进一步的推广,即把该方法运用于求解非对称线性鞍点问题之中,并给出了其收敛的充要条件.     

电子商务中混合数据加密技术的研究

由于电子商务拥有了更加丰富的信息、更加简单方便的交易和更加低廉的成本,受到了广大用户的欢迎。然而,现今阻碍电子商务快速发展的最大问题则是安全问题,数据加密技术是保证电子商务安全的核心技术,是电子商务安全技术的重要组成部分。目前使用的数据加密技术主要分成两种：对称加密技术和非对称加密技术。文章通过剖析数据加密技术中的RSA和DES算法的特点和缺点,提出一种混合加密算法用以规避两者的缺陷。