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9th International Conference on inf.rmatics in Control, Automation and Robotics, ICINCO 2012

作者： RǍdac, Mircea-Bogdan Bigher, Bogdan-Alexandru Precup, Radu-Emil Petriu, Emil M. Dragoş, Claudia-Adina Preitl, Stefan Stînean, Alexandra-Iulia Dept. of Automation and Appl. Inf. Politehnica University of Timisoara Bd. V. Parvan 2 300223 Timisoara Romania School of Electrical Eng. and Computer Science University of Ottawa 800 King Edward Ottawa ON K1N 6N5 Canada

ISBN: (纸本)9789898565211

This paper suggests the application of Iterative Feedback Tuning (IFT) as a data-based control technique to parameter tuning of PI controllers dedicated to vertical three-tank systems. The level control in the first two tanks is carried out using a multivariable control system structure which consists of two control loops, one for each level. The two PI controllers in these control loops are first tuned in terms of the Modulus Optimum method. New IFT algorithms are proposed in order to ensure the performance improvement of level control systems by means of six steps assisted by experiments. The experimental results show the strong performance improvement obtained after few iterations of IFT algorithms in terms of a model reference tracking optimization problem. Copyright © 2012 SciTePress.

关键词： Level control

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Adaptive gravitational search algorithm for PI-fuzzy controller tuning

Adaptive gravitational search algorithm for PI-fuzzy control...

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9th International Conference on inf.rmatics in Control, Automation and Robotics, ICINCO 2012

作者： David, Radu-Codrut Precup, Radu-Emil Petriu, Emil M. RǍdac, Mircea-Bogdan Purcaru, Constantin Dragoş, Claudia-Adina Preitl, Stefan Dept. of Automation and Appl. Inf. Politehnica University of Timisoara Bd. V. Parvan 2 300223 Timisoara Romania School of Electrical Eng. and Computer Science University of Ottawa 800 King Edward ON K1N 6N5 Ottawa Canada

ISBN: (纸本)9789898565211

This paper proposes an adaptive Gravitational Search Algorithm (aGSA) focused on tuning of Takagi- Sugeno PI-fuzzy controllers (T-S PI-FCs). The algorithm adapts two depreciation laws of the gravitational constant to the iteration index, a parameter in the weighted sum of all forces exerted from the other agents to the iteration index, and the reset at each stage of agents' worst fitnesses and positions to their best values. Two fuzzy logic blocks carry out the adaptation of the ratios of exploration runs and explanation runs using the ratio between the minimum and maximum Popov sums as an input variable. A tuning method for T-S PI-FCs dedicated to a class of nonlinear servo systems with an integral component and is offered, and T-S PI-FCs with reduced process gain sensitivity are tuned. A case study and digital simulation results illustrate the optimal tuning of a T-S PI-FC for the position control of a laboratory servo system. Copyright © 2012 SciTePress.

关键词： Controllers

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Exploring Employment Opportunities through Microtasks via Cybercafes

Exploring Employment Opportunities through Microtasks via Cy...

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IEEE Global Humanitarian Technology Conference (GHTC)

作者： Mrunal Gawade Rajan Vaish Mercy Nduta Waihumbu James Davis Department of Computer Science Centrum Wiskunde and Informatica Amsterdam Netherlands Department of Computer Science University of California Santa Cruz CA USA Dept. of Comput. Sci. Centrum Wiskunde & Inf. Amsterdam Netherlands

Microwork in cybercafés is a promising tool for poverty alleviation. For those who cannot afford a computer, cybercafés can serve as a simple payment channel and as a platform to work. However, there are questions about whether workers are interested in working in cybercafés, whether cybercafé owners are willing to host such a set up, and whether workers are skilled enough to earn an acceptable pay rate? We designed experiments in internet/cyber cafes in India and Kenya to investigate these issues. We also investigated whether computers make workers more productive than mobile platforms? In surveys, we found that 99% of the users wanted to continue with the experiment in cybercafé, while 8 of 9 cybercafé owners showed interest to host this experiment. User typing speed was adequate to earn a pay rate comparable to their existing wages, and the fastest workers were approximately twice as productive using a computer platform.

关键词： computers Mobile communication Mobile handsets Employment Educational institutions Sociology Statistics

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Probabilistic n-Choose-k Models for Classification and Ranking 12

Probabilistic n-Choose-k Models for Classification and Ranki...

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Annual Conference on Neural inf.rmation Processing Systems

作者： Kevin Swersky Daniel Tarlow Ryan P. Adams Richard S. Zemel Brendan J. Frey Dept. of Computer Science University of Toronto School of Eng. and Appl. Sciences Harvard University Prob. and Stat. Inf. Group University of Toronto

ISBN: (纸本)9781627480031

In categorical data there is often structure in the number of variables that take on each label. For example, the total number of objects in an image and the number of highly relevant documents per query in web search both tend to follow a structured distribution. In this paper, we study a probabilistic model that explicitly includes a prior distribution over such counts, along with a count-conditional likelihood that defines probabilities over all subsets of a given size. When labels are binary and the prior over counts is a Poisson-Binomial distribution, a standard logistic regression model is recovered, but for other count distributions, such priors induce global dependencies and combinatorics that appear to complicate learning and inf.rence. However, we demonstrate that simple, efficient learning procedures can be derived for more general forms of this model. We illustrate the utility of the formulation by exploring applications to multi-object classification, learning to rank, and top-K classification.

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On the interaction of existential rules and equality constraints in ontology querying

Lecture Notes in Computer Science (including subseries Lectu...

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Lecture Notes in computer science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinf.rmatics) 2012年 7265卷 117-133页

作者： Calì, Andrea Gottlob, Georg Orsi, Giorgio Pieris, Andreas Department of Computer Science University of Oxford United Kingdom Dept. of Computer Science and Inf. Systems Birkbeck University London United Kingdom Oxford-Man Institute of Quantitative Finance University of Oxford United Kingdom Institute for the Future of Computing Oxford Martin School United Kingdom

ISBN: (纸本)9783642307423

Ontological query processing is an exciting research topic in database theory, knowledge representation, and logic programming. In many cases, ontological constraints are expressed over an extensional database by extending traditional Datalog rules to allow existential quantification and equality atoms in the head. The unrestricted use of these features causes undecidability of query answering and, therefore, their interaction must be controlled. This work provides a tutorial-like introduction to the problem of query answering under existential and equality constraints. We survey the most notable (semantic and syntactic) restrictions to such constraints ensuring decidability of query answering, and we discuss their practical application to conceptual modelling. © 2012 Springer-Verlag Berlin Heidelberg.

关键词： Query processing

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AntSeg: The Application of Ant Colony Optimization to Interactive Image Segmentation

AntSeg: The Application of Ant Colony Optimization to Intera...

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computer science Society (SCCC) International Conference Chilean FLAGGED

作者： Tiago Alexandre Beraldi Versuti Franklin César Flores Mauro Henrique Mulati Airton Marco Polidorio Dept. of Inf. State Univ. of Maringa (UEM) Maringa Brazil Department of Computer Science Midwest State University (UNICENTRO) Guarapuava BRAZIL Department of Informatics State University of Maringá (UEM) Maringá BRAZIL

The computational process of image segmentation performs the partitioning of it in disjoint regions by the specification and application of specific criteria. This process can be automatic or interactive. The interactive process allows the user interference in this process by means of the insertion of new criteria at any instant of the process execution. This new criterion can lead to the reaching of more appropriate results for the solution to the problem. However, interactive process application requires the user to have a high ability, context knowledge and accuracy executing the tasks. The interactive process can include facilities by allowing that some user actions may be executed with relative accuracy. Using computational resources, such task is made easier, since a computer can perform with more accuracy and speed, from the guides interactively defined by the user. The literature presents many methods that perform this task, among them the live wire, intelligent scissors and the interactive watershed with markers. The first two use a minimum cost system, in other words, optimization, to their working. This paper proposes an interactive method applied to image segmentation that combines the artificial ant colonies behavior and the image gradient technique. The gradient, supplied by heuristic rules, is the surface the ants search the path to the desired solution. The segmentation starts with the imposition of an initial point at the border of the object of interest and, by the user adding new points along its border, new segments belonged to object border are conquered. The proposed method shows a high repeatability of the segmentation task.

关键词： Image segmentation Accuracy Color Ant colony optimization Image color analysis Computational modeling Context

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Gray Image Extraction Using Fuzzy Logic

Gray Image Extraction Using Fuzzy Logic

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International Conference on Advanced Computing & Communication Technologies (ACCT)

作者： Koushik Mondal Paramartha Dutta Siddhartha Bhattercharyya Indian Institute of Science Education and Research Pune Indian Institute of Science Education and Research Pune India Department of Computer & System Sciences Visva-Bharati University Santiniketan West Bengal India Dept. of CS & IT RCC Inst. of Inf. Technol. Kolkata India

Fuzzy systems concern fundamental methodology to represent and process uncertainty and imprecision in the linguistic inf.rmation. The fuzzy systems that use fuzzy rules to represent the domain knowledge of the problem are known as Fuzzy Rule Base Systems (FRBS). On the other hand image segmentation and subsequent extraction from a noise-affected background, with the help of various soft computing methods, are relatively new and quite popular due to various reasons. These methods include various Artificial Neural Network (ANN) models (primarily supervised in nature), Genetic Algorithm (GA) based techniques, intensity histogram based methods etc. providing an extraction solution working in unsupervised mode happens to be even more interesting problem. Literature suggests that effort in this respect appears to be quite rudimentary. In the present article, we propose a fuzzy rule guided novel technique that is functional devoid of any external intervention during execution. Experimental results suggest that this approach is an efficient one in comparison to different other techniques extensively addressed in literature. In order to justify the supremacy of performance of our proposed technique in respect of its competitors, we take recourse to effective metrics like Mean Squared Error (MSE), Mean Absolute Error (MAE), Peak Signal to Noise Ratio (PSNR).

关键词： Image segmentation Object segmentation Image edge detection Histograms Image color analysis Noise

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Requirements evolution drives software evolution

Requirements evolution drives software evolution

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2011 12th International Workshop on Principles on Software Evolution and 7th ERCIM Workshop on Software Evolution, IWPSE-EVOL'11

作者： Ernst, Neil A. Borgida, Alexander Mylopoulos, John Dept. of Computer Science University of Toronto Toronto ON Canada Dept. of Computer Science Rutgers University New Brunswick NJ United States Dept. of Inf. Eng. and Computer Science University of Trento Trento Italy

ISBN: (纸本)9781450308489

Changes to software should be made with reference to the requirements of that software, as these requirements provide the reasons for a change. Requirements serve to tie the implementation world of the developers to the problem world of the stakeholders. Most empirical studies of requirements have shown that misunderstood and changing requirements cause the majority of failures and costs in software. However, research in software evolution has typically focused on how to evolve software and not why. In our view, evolving software is about solving requirements problems, that is, finding new implementations which will satisfy the requirements while respecting domain assumptions. We argue that by describing this relationship, an implementation choice that best meets stakeholder needs can be made. We describe a tool that models requirements problems. This tool can find incremental solutions to evolving requirements problems quickly. © 2011 ACM.

关键词： Problem solving

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Efficient rank join with aggregation constraints 37

Efficient rank join with aggregation constraints

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37th International Conference on Very Large Data Bases, VLDB 2011

作者： Xie, Min Lakshmanan, Laks V.S. Wood, Peter T. Dept. of Computer Science Univ. of British Columbia Canada Dept. of CS and Inf. Syst. Birkbeck U. of London United Kingdom

We show aggregation constraints that naturally arise in several applications can enrich the semantics of rank join queries, by allowing users to impose their application-specific preferences in a declarative way. By analyzing the properties of aggregation constraints, we develop ecient deterministic and probabilistic algorithms which can push the aggregation constraints inside the rank join framework. Through extensive experiments on various datasets, we show that in many cases our proposed algorithms can significantly outperform the naive approach of applying the state-of-theart rank join algorithm followed by post-filtering to discard results violating the constraints. © 2011 VLDB Endowment.

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Investigation of main memory bandwidth on intel single-chip cloud computer

Investigation of main memory bandwidth on intel single-chip ...

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3rd Symposium on Many-Core Applications Research Community, MARC 2011

作者： Melot, Nicolas Avdic, Kenan Kessler, Christoph Keller, Jörg Linköpings Universitet Dept. of Computer and Inf. Science 58183 Linköping Sweden Fern Universität in Hagen Fac. of Math. and Computer Science 58084 Hagen Germany

ISBN: (纸本)9783866447172

The Single-Chip Cloud computer (SCC) is an experimental processor created by Intel Labs. It comprises 48 x86 cores linked by an on-chip high performance network, as well as four DDR3 memory controllers to access an off-chip main memory of up to 64GiB. This work evaluates the performance of the SCC when accessing the off-chip memory. The focus of this study is not on taxing the bare hardware. Instead, we are interested in the performance of applications that run on the Linux operating system and use the SCC as it is provided. We see that the per-core read memory bandwidth is largely independent of the number of cores accessing the memory simultaneously, but that the write memory access performance drops when more cores write simultaneously to the memory. In addition, the global and per-core memory bandwidth, both writing and reading, depends strongly on the memory access pattern.

关键词： Bandwidth

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