: An efficient B + -tree design for main-memory database system

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Title: An efficient B + -tree design for main-memory database systems with strong access locality

Authors: PeiLun Suei a , Victor CS Lee b,fi , ShiWu Lo c , TeiWei Kuo

Abstract: This paper is motivated by the strong demands of many main-memory database applications with strong locality in data access, such as front-end logistical systems. We propose to adopt an auxiliary-tree approach with an tree-merging algorithm to efficiently handle bursty data insertions with keys in a small range and avoid significant overheads in tree rebalancing. A range-based deletion algorithm is then proposed to process data deletions with strong access locality in a batch fashion. The capability of the proposed approach is evaluated by a series of experiments with a wide range of workloads and a variety of locality patterns, where different tree index structures are compared in terms of the performance and memory space requirements.   

Publish Year: 2013

Published in: Information Sciences - Science Direct

Number of Pages: 21

موضوع: پایگاه داده (Data Base)

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Function optimisation by learning automata

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Title: Function optimisation by learning automata

Authors: QH Wu , HL Liao

Abstract: This paper presents a new algorithm, Function Optimisation by Learning Automata (FOLA), to solve complex function optimisation problems. FOLA consists of multiple automata, in which each automaton undertakes dimensional search on a selected dimension of the solution domain. A search action is taken on a path which is identified in the search space by the path value, and the path value is updated using the values of the states visited in the past, via a state memory that enables better use of the information collected in the optimisation process. In this paper, FOLA is compared with two popularly used particle swarm optimisers and four newly-proposed optimisers, on nine complex multi-modal benchmark functions. The experimental results have shown that in comparison with the other optimisers, FOLA offers better performance for most of the benchmark functions, in terms of its convergence rate and accuracy, and it uses much less computation time to obtain accurate solutions, especially for high-dimensional functions. In order to explore the FOLA s potential for applications, it is also applied to solve an optimal power flow problem of power systems. FOLA is able to minimise the fuel cost and enhance the voltage stability of the power system more efficiently in comparison with the other algorithms.  

Publish Year: 2013

Published in: Information Sciences - Science Direct

Number of Pages: 20

موضوع: اتوماتای یادگیر (Learning Automata)

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A high abstraction level approach for detecting feature interact

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Title: A high abstraction level approach for detecting feature interactions between telecommunication services

Authors: Zohair Chentouf, Ahmed Khoumsi

Abstract: When several telecommunication services are running at the same time, undesirable behaviors may arise, which are commonly called feature interactions. Several methods have been developed for detecting and resolving feature interactions. However, most of these methods are based on detailed models of services, which make them suffer from state space explosion. Moreover, different telecommunication operators cannot cooperate to manage feature interactions by exchanging detailed service models because this violates the confidentiality principle. Our work is a part of the few attempts to develop feature interaction detection methods targeting to avoid or reduce significantly state space explosion. In order to reach this objective, we first develop a so called Cause Restrict language to model subscribers of telecommunication services at a very high abstraction level. A Cause Restrict model of a subscriber provides information such as: what is the cause of what, and what restricts (or forbids) what, and specifies coarsely the frequency of each operation cause or restrict by always or sometimes. Then, we develop a method that detects feature interactions between telecommunication services modeled in the Cause Restrict language. We demonstrate the applicability of our approach by modeling several services and detecting several feature interactions between them. New feature interactions have been detected by our approach.   

Publish Year: 2013

Published in: Information Sciences - Science Direct

Number of Pages: 17

موضوع: مخابرات (Telecommunication)

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Fractal behind coin-reducing payment

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Title: Fractal behind coin-reducing payment

Authors: Ken Yamamoto , Yoshihiro Yamazaki

Abstract: The minimal payment a payment method which minimizes the number of coins in a purse is presented. We focus on a time series of change given back to a shopper repeating the minimal payment. By using the delay plot, the set of successive change possesses a fine structure similar to the Sierpinski gasket. We also estimate affectivity of the minimal- payment method by means of the average number of coins in a purse, and conclude that the minimal-payment strategy is the best to reduce the number of coins in a purse. More- over, we compare our results to the rule-60 cellular automaton and the Pascal Sierpinski gaskets, which are known as generators of the discrete Sierpinski gasket.   

Publish Year: 2012

Published in: Chaos, Solitons & Fractals - Science Direct

Number of Pages: 9

موضوع: فرکتال (Fractal)

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Slender-Set Differential Cryptanalysis

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Title: Slender-Set Differential Cryptanalysis

Authors: Julia Borghoff, Lars R Knudsen, Gregor Leander, and Sren S Thomsen

Abstract: This paper considers PRESENT-like ciphers with key-dependent S-boxes. We focus on the setting where the same selection of S-boxes is used in every round. One particular variant with 16 rounds, proposed in 2009, is broken in practice in a chosen plaintext/chosen cipher text scenario. Extrapolating these results suggests that up to 28 rounds of such ciphers can be broken. Furthermore, we outline how our attack strategy can be applied to an extreme case where the S-boxes are chosen uniformly at random for each round, and where the bit permutation is key-dependent as well.   

Publish Year: 2013

Published in: Journal of Cryptography - Journal of Springer

Number of Pages: 28

موضوع: رمزنگاری (Cryptography)

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