基于带有惩罚因子的阴性选择算法的恶意程序检测模型

提出了一个基于带有惩罚因子的阴性选择算法的恶意程序检测模型.该模型从指令频率和包含相应指令的文件频率两个角度出发,对指令进行了深入的趋向性分析,提取出了趋向于代表恶意程序的恶意程序指令库.利用这些指令,有序切分程序比特串,模型提取得到恶意程序候选特征库和合法程序类恶意程序特征库.在此基础上,文中提出了一种带有惩罚因子的阴性选择算法(negative selection algorithm with penalty factor,NSAPF),根据异体和自体的匹配情况,采用惩罚的方式,对恶意程序候选特征进行划分,组成了恶意程序检测特征库1(malware detection signature library 1,MDSL1)和恶意程序检测特征库2(MDSL2),以此作为检测可疑程序的二维参照物.综合可疑程序和MDSL1,MDSL2的匹配值,文中模型将可疑程序分类到合法程序和恶意程序.通过在阴性选择算法中引入惩罚因子C,摆脱了传统阴性选择算法中对自体和异体有害性定义的缺陷,继而关注程序代码本身的危险性,充分挖掘和调节了特征的表征性,既提高了模型的检测效果,又使模型可以满足用户对识别率和虚警率的不同要求.综合实验...     

Comparison of the RF MEMS switches with dielectric layers on the bridge’s lower surface and on the transmission line

Previously, we proposed that the dielectric layer of RF MEMS switch can be fabricated either on the transmission line, as traditional switches, or on the lower surface of the bridge. This paper presents a detailed comparison of the RF MEMS switches with different positions of dielectric layer. Through theoretically analyzing the physical model of fringing capacitance, it is revealed that different positions of dielectric layer can result in different switch capacitances. Therefore, the change of d...     

AutoProc: An automatic proactive replication scheme for P2P storage

Due to the prevalence of peer departures, P2P storage systems need to constantly generate replicas for high durability. However, few existing systems are able to select the right replication rate that balances replication cost and durability, e.g., minimizing replication cost without threatening the durability target. In this paper, we propose a method called AutoProc to automate the replication process in P2P storage systems. AutoProc employs two key techniques to enable cost-effective replication: correct...     

Zero-knowledge proofs of retrievability

Proof of retrievability (POR) is a technique for ensuring the integrity of data in outsourced storage services.In this paper,we address the construction of POR protocol on the standard model of interactive proof systems.We propose the first interactive POR scheme to prevent the fraudulence of prover and the leakage of verified data.We also give full proofs of soundness and zero-knowledge properties by constructing a polynomial-time rewindable knowledge extractor under the computational Diffie-Hellman assump...     

Sorcery: Overcoming deceptive votes in P2P content sharing systems

Deceptive voting behaviors of malicious users are known as the main reason of causing content pollution in Peer-to-Peer (P2P) content sharing systems. Due to the nature of P2P overlay network such as self-organization and anonymity, the existing methods on identifying deceptive votes are not effective, especially for collusive attackers. This paper presents Sorcery, a novel active challenge-response mechanism based on the notion that one side of interaction with the dominant information can detect whether the other side is telling a lie. To make each client obtain the dominant information, our approach introduces the social network to the P2P content sharing system; therefore, clients can establish the friend-relationships with the users who are either acquaintances in reality or those reliable online friends. Using the confidential voting histories of friends as own dominant information, the client challenges target content providers with the overlapping votes of both his friends and the target content provider, thus detecting whether the content provider is a deceptive user. Moreover, Sorcery provides the punishment mechanism which can reduce the impact brought by deceptive voting behaviors, and our work also discusses some key practical issues. The experimental results illustrate that Sorcery can effectively overcome the problem of deceptive voting behaviors in P2P content sharing systems, and work better than the existing reputation models.     

Nonsingular fast terminal sliding‐mode control for nonlinear dynamical systems

This paper investigates fast finite‐time control of nonlinear dynamics using terminal sliding‐mode (TSM) scheme. Some new norms of fast TSM strategies are proposed, and a faster convergence rate is established in comparison with the conventional fast TSM. A novel concept of nonsingular fast TSM, which is able to avoid the possible singularity during the control phase, is adopted in the robust high‐precision control of uncertain nonlinear systems. Numerical simulation on a two‐link rigid robot manipulator demonstrates the effectiveness of the proposed algorithm. Copyright © 2010 John Wiley & Sons, Ltd.     

Summary queries for frequent itemsets mining

There are many advanced techniques that can efficiently mine frequent itemsets using a minimum-support. However, the question that remains unanswered is whether the minimum-support can really help decision makers to make decisions. In this paper, we study four summary queries for frequent itemsets mining, namely, (1) finding a support-average of itemsets, (2) finding a support-quantile of itemsets, (3) finding the number of itemsets that greater/less than the support-average, i.e., an approximated distribution of itemsets, and (4) finding the relative frequency of an itemset (compared its frequency with that of other itemsets in the same dataset). With these queries, a decision maker will know whether an itemset in question is greater/less than the support-quantile; the distribution of itemsets; and the frequentness of an itemset. Processing these summary queries is challenging, because the minimum-support constraint cannot be used to prune infrequent itemsets. In this paper, we propose several simple yet effective approximation solutions. We conduct extensive experiments for evaluating our strategy, and illustrate that the proposed approaches can well model and capture the statistical parameters (summary queries) of itemsets in a database.     

Efficient evaluation of query rewriting plan over materialized XML view

The query rewriting plan generation over XML views has received wide attention recently. However, little work has been done on efficient evaluation of the query rewriting plans, which is not trivial since the plan may contain an exponential size of sub-plans. This paper investigates the reason for the potentially exponential number of sub-plans, and then proposes a new space-efficient form called ABCPlan (Plan with Automata Based Combinations) to equivalently represent the original query rewriting plan. ABCPlan contains a set of buckets containing suffix paths in the query tree and an automata to indicate the combination of the suffix paths from different buckets as valid query rewriting sub-plans. We also design an evaluation method called ABCScan, which constructs a unified evaluation tree for the ABCPlan and handles the evaluation tree in one scan of the XML view. In the evaluation, we introduce node existence automata to encode the structure of the sub-tree and convert the satisfaction of the ABCPlan into the intersection problem of deterministic finite automata. The experiments show that ABCPlan based method outperforms existing methods significantly in terms of scalability and efficiency.     

kμ-Tree:一种空间有效的嵌入式闪存数据库索引

μ-Tree是直接建立在闪存之上的索引,它克服了传统B+树应用于闪存时引起的"游走树"现象,避免更新一页累及多页的现象.但μ-Tree也存在缺点:占用空间比传统B+树多.为克服μ-Tree存在的缺点,本文提出一套机制改进μ-Tree:k分法模型.在此模型中,我们分析了在给定扇出度F时,k值与总记录数n的关系,以及给定记录数n时,不同大小的索引记录项对k的影响;给出了确定k值的基本方法.实验结果表明,k比例划分可以有效地节省索引所占空间,空间节省最大达50%左右,平均可达39%.所提方法在空间资源受限的环境下具有良好的空间特性.     

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