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101.
LiuZhong ZhouYunfei LiPeigen Duan Zhengcheng School of Mechanical Science Engineering Huazhong University of Science Technology Wuhan China Manufacturing Production 《计算机辅助绘图.设计与制造(英文版)》2001,(2)
We propose in this paper a genetic algorithm (GA)-based approach to solve the Flexible Manufacturing System (FMS) formation problem. First, we divide the unity of machines into small groups or cells using Group Technology (GT). And an option for considering the minimization of workload variation between cells is included. Then the implementation is done using GA. When using GA, the designer is allowed to specify the number of cells and impose lower and upper bounds on cell size. This makes the GA scheme flexible for solving the FMS formation problems. 相似文献
102.
103.
分析了电子商务的安全需求、面临的主要安全问题,并在对入侵行为进行分类研究的基础上,对电子商务活动流程的描述和脆弱点分析中研究了其安全对策. 相似文献
104.
网络信息安全的最终任务是保护信息的安全,为此,需要制定合理的安全体系,在安全体系指导下综合应用各种安全理论与技术。本文结合作者的体会,介绍安全体系设计知识。一个好的安全体系必须充分考虑安全需求、安全威胁、安全技术、安全指标、安全法规、安全实施、安全产品和安全代价等各方面的要素。本文侧重于从技术角度介绍安全体系设计的思路。 相似文献
105.
In this paper, a new hybrid parallelisable low order algorithm, developed by the authors for multibody dynamics analysis,
is implemented numerically on a distributed memory parallel computing system. The presented implementation can currently accommodate
the general spatial motion of chain systems, but key issues for its extension to general tree and closed loop systems are
discussed. Explicit algebraic constraints are used to increase coarse grain parallelism, and to study the influence of the
dimension of system constraint load equations on the computational efficiency of the algorithm for real parallel implementation
using the Message Passing Interface (MPI). The equation formulation parallelism and linear system solution strategies which
are used to reduce communication overhead are addressed. Numerical results indicate that the algorithm is scalable, that significant
speed-up can be obtained, and that a quasi-logarithmic relation exists between time needed for a function call and numbers
of processors used. This result agrees well with theoretical performance predictions. Numerical comparisons with results obtained
from independently developed analysis codes have validated the correctness of the new hybrid parallelisable low order algorithm,
and demonstrated certain computational advantages. 相似文献
106.
讨论了在Windows环境下用 Delphi3开发半导体应力自动测量系统控制软件的方法和关键细节。介绍硬件与软件调试中要注意的问题。对 Windows环境下开发控制硬件工作的软件进行了探讨。 相似文献
107.
108.
Zhenhai Duan Xin Yuan Chandrashekar J. 《Dependable and Secure Computing, IEEE Transactions on》2008,5(1):22-36
The distributed denial-of-service (DDoS) attack is a serious threat to the legitimate use of the Internet. Prevention mechanisms are thwarted by the ability of attackers to forge or spoof the source addresses in IP packets. By employing IP spoofing, attackers can evade detection and put a substantial burden on the destination network for policing attack packets. In this paper, we propose an interdomain packet filter (IDPF) architecture that can mitigate the level of IP spoofing on the Internet. A key feature of our scheme is that it does not require global routing information. IDPFs are constructed from the information implicit in border gateway protocol (BGP) route updates and are deployed in network border routers. We establish the conditions under which the IDPF framework correctly works in that it does not discard packets with valid source addresses. Based on extensive simulation studies, we show that, even with partial deployment on the Internet, IDPFs can proactively limit the spoofing capability of attackers. In addition, they can help localize the origin of an attack packet to a small number of candidate networks. 相似文献
109.
FOXPRO RDBMS是一种安全性很弱的关系数据库管理系统,而一般的FOXPRO数据库应用系统除了口令字机制之外,也很少有其它的保护措施。为此,本文提出一种称为“角色-视图”关系的适应于办公室环境的数据库访问控制策略。在这种策略的指导下,利用NO-VELL NetWare网络操作系统的安全机制,设计了一个在应用层上的FOXPRO数据库系统安全体系。本文所做的研究工作有两个特点:一是数据库系统安全的关键功能利用操作系统和机制来实现,所以系统整体在安全性、性能和开发费用上有较好的平衡;二是整个安全体系的设计符合安全工程的一般开发流程。 相似文献
110.
Xiao ZQ Chen Y Yi B Li MY Zhang PF Yi H Duan CJ Li C Li JL Tang CE Yang F Zhu GQ Chen ZC 《Proteomics. Clinical applications》2007,1(7):688-698
A proteomics-based approach has been used to identify proteins that commonly elicit a humoral immune response in nasopharyngeal carcinoma (NPC). Sera from 19 newly diagnosed NPC patients and 19 healthy individuals were analyzed for IgG autoantibodies against NPC proteins resolved by 2-DE. Protein spots that exhibited selective reactivity with sera from NPC patients were identified by MS. Among nine identified proteins, cytokeratin 19 (CK19), Erb3 binding protein (EBP1), and Rho GDP dissociation inhibitor-beta (Rho-GDI-2) induced autoantibodies in more than 36.8% of NPC patients but not in healthy individuals. Furthermore, Western blot analysis and immunohistochemical staining were performed to determine the expression and localization of CK19, EBP1, and Rho-GDI-2 in NPC and normal nasopharyngeal mucosal tissues. Up-regulated CK19 and EBP1, but not Rho-GDI-2, were observed in NPC vs. normal tissue. Subcellular localization of the three proteins in NPC tissue was same as that in the normal tissue. Thus, overexpression of CK19 and EBP1 may be one of the mechanisms for their autoantibody development in NPC. To validate the findings of a proteomic analysis, occurrence of autoantibodies against these three proteins was detected by immunoprecipitation and Western blot analysis in additional 30 NPC patients, 23 other types of cancer patients and 20 healthy individuals. Results showed that frequency of autoantibodies against CK19, EBP1 and Rho-GDI-2 in NPC patients was significantly higher than that in other types of cancer patients and healthy individuals. We conclude that CK19, EBP1 and Rho-GDI-2 may have utility in NPC screening and diagnosis. 相似文献