This paper describes a methodology to support the design process of complex systems. The main challenge in modern industrial applications is the sheer volume of data involved in the design process. While using high-le...
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This paper describes a methodology to support the design process of complex systems. The main challenge in modern industrial applications is the sheer volume of data involved in the design process. While using high-level abstraction is necessary to manage this data and analyze the system "as a whole", designers need also to retain all the low-level information of the system, in order to be able to perform optimizations and modifications at later times. The solution proposed here is to use a hierarchy of models that describe the system at different levels of abstraction, and are arranged in such a way that is possible to easily "map" each level onto the others. The topmost layer of the system description is expressed in System Modeling Language (SysML), a general-purpose modeling language based on UMLreg
We describe an approach to on-the-fly real-time testing based on non-deterministic timed automata. The approach is based on standard computations on zone automata. We present algorithms for practical testing, as they ...
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We describe an approach to on-the-fly real-time testing based on non-deterministic timed automata. The approach is based on standard computations on zone automata. We present algorithms for practical testing, as they were implemented in the testing tool TorX.
Women represent only one fifth of engineering bachelor's degree recipients in the U.S. This gender gap has stubbornly held for the past several years. Based on survey and interview data, this study examines the ex...
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Women represent only one fifth of engineering bachelor's degree recipients in the U.S. This gender gap has stubbornly held for the past several years. Based on survey and interview data, this study examines the experiences and perspectives of 40 first-year women and men intending to study engineering at a public, research extensive university. We found that, regardless of gender, students view math, science, and other technical abilities as foundational in engineering. However, our findings also provide a complex picture of gender differences in the experiences and ways of thinking beginning undergraduates associate with engineering. With a more detailed understanding of what distinguishes women as early successes in the possible engineering pathways, this study provides empirical grounds for portraying engineering more broadly in order to recruit more women
Time series forecasting has been widely used to support decision making, in this context a highly accurate prediction is essential to ensure the quality of the decisions. Ensembles of machines currently receive a lot ...
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Time series forecasting has been widely used to support decision making, in this context a highly accurate prediction is essential to ensure the quality of the decisions. Ensembles of machines currently receive a lot of attention; they combine predictions from different forecasting methods as a procedure to improve the accuracy. This paper explores genetic programming and boosting technique to obtain an ensemble of regressors and proposes a new formula for the final hypothesis. This new formula is based on the correlation coefficient instead of the geometric median used by the boosting algorithm. To validate this method, experiments were performed, the mean squared error (MSE) has been used to compare the accuracy of the proposed method against the results obtained by GP, GP using a boosting technique and the traditional statistical methodology (ARMA). The results show advantages in the use of the proposed approach
A common difficulty for the existing global optimization methods is that they are not easy to escape from the local optimal solutions and therefore often not find the global optimal solution. In order to make it escap...
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A common difficulty for the existing global optimization methods is that they are not easy to escape from the local optimal solutions and therefore often not find the global optimal solution. In order to make it escapes from the local optimal solutions and find the global optimal solution easier, first, the authors construct a smoothing function. It can eliminate all such local optimal solutions worse than the best solution found so far. Moreover, it can keep the original function unchanged in the region in which the values of the original function are not worse than its value at the best solution found so far. Thus, if optimizing this smoothing function instead of the original objective function, the number of the local optimal solutions will be largely decreased with progress of the iterations. As a result, it becomes much easier for an algorithm to find a global optimal solution. Second, a new crossover operator is designed based on the properties of the smoothing function. It can adaptively generate high quality offspring for any situation. Third, by making use of the properties of the smoothing function, the line search technique is properly combined into the algorithm design, which will make the proposed algorithm converge much faster. Based on all these, a novel effective evolutionary algorithm for global optimization is proposed and its global convergence is proved. At last, the numerical simulations for several standard benchmark problems are made and the simulation results show that the proposed algorithm is very effective.
We propose in this paper a new Bluetooth authentication scheme based on game-theoretic setting. Bluetooth is a short-ranged wireless communication protocol that can be used between different Bluetooth enabled devices ...
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We propose in this paper a new Bluetooth authentication scheme based on game-theoretic setting. Bluetooth is a short-ranged wireless communication protocol that can be used between different Bluetooth enabled devices (cell phones, laptops, PDAs,...). It has been chosen as a baseline of the IEEE (Institute of Electronic and Electrical Engineers) 802.15.1 standard for WPANs (Wireless Personal Area Neworks). Game theory is a branch of mathematics and logic which deals with the analysis of games. It is a formal study of interactive decision processes [13]. It enhances the understanding of conflict and cooperation by mathematical models and abstractions. An authentication between two Bluetooth devices is an unidirectional challenge-response procedure and consequently, has many vulnerabilities. We model a bidirectional Bluetooth authentication as a noncooperative non-zero-sum bimatrix game. Three strategies are defined for each player, and the best-responses strategies (also called Nash equilibria) for this game are computed. Using Simplex algorithm, we find only one Nash equilibrium corresponding to the case where both Bluetooth devices are trusted and trying to securily communicate together. In a Nash equilibrium, no player has an incentive to deviate from such situation. Our model is then implemented in the application level using the Windows Bluetooth socket stack.
Markov chains are widely used to determine system performance and reliability characteristics. The vast majority of applications considers continuous-time Markov chains (CTMCs). This note motivates how concurrency the...
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Markov chains are widely used to determine system performance and reliability characteristics. The vast majority of applications considers continuous-time Markov chains (CTMCs). This note motivates how concurrency theory can be extended (as opposed to twisted ) to CTMCs. We provide the core motivation for the algebraic setup of Interactive Markov Chains . Therefore, this note should have better been baptized YIMC.
In this paper, we try to throw light on the information content of base rates announcements released by the National Bank of Poland (NBP). Focusing our attention on the rediscount rate changes over the period from 199...
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In this paper, we try to throw light on the information content of base rates announcements released by the National Bank of Poland (NBP). Focusing our attention on the rediscount rate changes over the period from 1995 to 2003, we examine whether the abnormal behavior of stock returns and trading volume of the most liquid firms listed on the Warsaw Stock Exchange (WSE) can be identified in the surroundings of the NBP announcements. The statistical test used here is based on the excess returns (volume) defined as the difference between actual rate of return (volume) and expected rate of return (volume). To generate the expected returns (volume), we employ the ARMA(1,1)-GARCH(1,1) specification with additional repressor, that is, return of the market portfolio (approximated by the market-capitalization weighted stock index called WIG) in the mean equation. The main finding is that the reversal of rediscount rate course has a significant impact on stock returns but not on trading volume.
Design derivation, a correct-by-construction system design method, specifies behavior with abstract datatypes. Refining these abstract datatypes is necessary for architectural decomposition. A new transformation primi...
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The notion of an algorithm is fundamental in computerscience. Yet, it is not always fully conceived by novices. This paper focuses on a particular facet of algorithm conception - the relationship between an algorithm...
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ISBN:
(纸本)1595930248
The notion of an algorithm is fundamental in computerscience. Yet, it is not always fully conceived by novices. This paper focuses on a particular facet of algorithm conception - the relationship between an algorithmic problem, its analysis, and its desired algorithmic solution. The paper displays evidence that novices demonstrate cognitive obstacles regarding the notion of an algorithm, which relate to a process-object duality phenomena [13] and inadequate classroom norms of communication. Copyright 2005 ACM.
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