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91.
面向攻击图构建的网络连通性分析   总被引:1,自引:0,他引:1       下载免费PDF全文
针对目前网络攻击图构建系统的需求,设计网络连通性分析算法。通过对网络拓扑及防火墙规则进行离线分析,可以判断网络中由若干台过滤设备分隔的任意2台主机间的连通性。引入关键实体集的概念,结合经典的Apriori算法提出一种快速有效的获取关键实体集的方法。分析对比表明,关键实体集可以在连通性分析过程中为网络中各节点的重要性评估提供有力依据。  相似文献   
92.
Surrogate models are used to dramatically improve the design efficiency of numerical aerodynamic shape optimization, where high-fidelity, expensive computational fluid dynamics (CFD) is often employed. Traditionally, in adaptation, only one single sample point is chosen to update the surrogate model during each updating cycle, after the initial surrogate model is built. To enable the selection of multiple new samples at each updating cycle, a few parallel infilling strategies have been developed in recent years, in order to reduce the optimization wall clock time. In this article, an alternative parallel infilling strategy for surrogate-based constrained optimization is presented and demonstrated by the aerodynamic shape optimization of transonic wings. Different from existing methods in which multiple sample points are chosen by a single infill criterion, this article uses a combination of multiple infill criteria, with each criterion choosing a different sample point. Constrained drag minimizations of the ONERA-M6 and DLR-F4 wings are exercised to demonstrate the proposed method, including low-dimensional (6 design variables) and higher-dimensional problems (up to 48 design variables). The results show that, for surrogate-based optimization of transonic wings, the proposed method is more effective than the existing parallel infilling strategies, when the number of initial sample points are in the range from N v to 8N v (N v here denotes the number of design variables). Each case is repeated 50 times to eliminate the effect of randomness in our results.  相似文献   
93.
Impact of the discrete dopants on device performance is crucial in determining the behavior of nanoscale semiconductor devices. Atomistic quantum mechanical device simulation for studying the effect of discrete dopants on device's physical quantities is urgent. This work explores the physics of discrete-dopant-induced characteristic fluctuations in 16-nm fin-typed field effect transistor (FinFET) devices. Discrete dopants are statistically positioned in the three-dimensional channel region to examine associated carrier's characteristic, concurrently capturing “dopant concentration variation” and “dopant position fluctuation”. An experimentally validated quantum hydrodynamic device simulation was conducted to investigate the potential profile and threshold voltage fluctuations of the 16-nm FinFET. Results of this study provide further insight into the problem of fluctuation and the mechanism of immunity against fluctuation in 16-nm devices.  相似文献   
94.
This paper analyzes the execution behavior of “No Random Accesses” (NRA) and determines the depths to which each sorted file is scanned in growing phase and shrinking phase of NRA respectively. The analysis shows that NRA needs to maintain a large quantity of candidate tuples in growing phase on massive data. Based on the analysis, this paper proposes a novel top-k algorithm Top-K with Early Pruning (TKEP) which performs early pruning in growing phase. General rule and mathematical analysis for early pruning are presented in this paper. The theoretical analysis shows that early pruning can prune most of the candidate tuples. Although TKEP is an approximate method to obtain the top-k result, the probability for correctness is extremely high. Extensive experiments show that TKEP has a significant advantage over NRA.  相似文献   
95.
96.
Implementation and maintenance of interorganizational systems (IOS) require investments by all the participating firms. Compared with intraorganizational systems, however, there are additional uncertainties and risks. This is because the benefits of IOS investment depend not only on a firm’s own decisions, but also on those of its business partners. Without appropriate levels of investment by all the firms participating in an IOS, they cannot reap the full benefits. Drawing upon the literature in institutional economics, we examine IOS ownership as a means to induce value-maximizing noncontractible investments. We model the impact of two factors derived from the theory of incomplete contracts and transaction cost economics: relative importance of investments and specificity of investments. We apply the model to a vendor-managed inventory system (VMI) in a supply chain setting. We show that when the specificity of investments is high, this is a more critical determinant of optimal ownership structure than the relative importance of investments. As technologies used in IOS become increasingly redeployable and reusable, and less specific, the relative importance of investments becomes a dominant factor. We also show that the bargaining mechanism—or the agreed upon approach to splitting the incremental payoffs—that is used affects the relationship between these factors in determining the optimal ownership structure of an IOS.
Barrie R. NaultEmail:
  相似文献   
97.
Li KW  Yu RF  Han XL 《Applied ergonomics》2007,38(3):259-265
A study on combined manual materials-handling tasks performed on floors under three friction levels was conducted. Eight male subjects participated in the study. The maximum acceptable weight of handling, including lifting, carrying for 3m, lowering, and walking 3m back at twice per minute was determined. The subject then performed the same tasks for 10 min. Heart rate, Vo2, energy efficiency, perceived sense of slip, and rating of perceived exertion for whole body strain were measured. The results showed that the effects of friction level on the maximum acceptable weights of handling, perceived sense of slip, Vo2, and energy efficiency were statistically significant (p相似文献   
98.
韩世聪 《微型电脑应用》2000,16(6):22-23,33
本文从互连网发展的趋势入手,对路径模式发掘进行了研究。先简要介绍数据库发掘的概况及网上数据发掘的特点,后结合关联法和组合概率法,并以算法和实例详细对之进行分析。  相似文献   
99.
Scalable parallel data mining for association rules   总被引:3,自引:0,他引:3  
The authors propose two new parallel formulations of the Apriori algorithm (R. Agrawal and R. Srikant, 1994) that is used for computing association rules. These new formulations, IDD and HD, address the shortcomings of two previously proposed parallel formulations CD and DD. Unlike the CD algorithm, the IDD algorithm partitions the candidate set intelligently among processors to efficiently parallelize the step of building the hash tree. The IDD algorithm also eliminates the redundant work inherent in DD, and requires substantially smaller communication overhead than DD. But IDD suffers from the added cost due to communication of transactions among processors. HD is a hybrid algorithm that combines the advantages of CD and DD. Experimental results on a 128-processor Cray T3E show that HD scales just as well as the CD algorithm with respect to the number of transactions, and scales as well as IDD with respect to increasing candidate set size  相似文献   
100.
纳米SiO2材料的应用   总被引:11,自引:1,他引:11  
本文根据纳米的奇异特性,简要综述纳米SiO2在各个领域中的应用。  相似文献   
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