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This work treats a forest planning problem stemming from the daily operation of some large pulp and paper companies. The problem consists in planning and scheduling harvest and transportation activities for each day in a planning horizon of around one year, while satisfying a sizable and complex set of constraints related to the structure of the harvest areas, structure and productivity of the harvest...
Biometrics is one of the biggest tendencies in human identification. The fingerprint is the most widely used biometric. However considering the automatic fingerprint recognition a completely solved problem is a common mistake. The most popular and extensively used methods, the minutiae-based, do not perform well on poor-quality images and when just a small area of overlap between the template and...
Conventional e-mail systems are prone to problems that affect their dependability. E-mail systems operate following a "push-based" approach: the sender side server pushes the e-mails it wants to send to the corresponding receivers' servers. This approach may impose processing and storage overhead on the receiver side. This paper presents a peer-to-peer e-mail system in which messages are...
Grid computing is becoming more and more popular nowadays, but it does not mean that it is becoming easy to use, deploy and program. OGSA-DAI is a middleware capable of exposing and managing databases on the grid. In this work we present an extension to the OGSA-DAI grid middleware, this extension is an implementation of the Sun JDBC interface, used to access databases within the Java language. This...
This paper presents a novel model for combining projection and image filtering in computerized tomography. First, it is used an a priori one-dimensional projection filtering, through an extended Kalman filter with joint estimation. Then, the reconstructed images, obtained filtered backprojection algorithms (including the use of Hamming windows), are filtered using the two-dimensional DWT and wavelet...
This paper presents a novel method to initialize the LSTM network weights in order to improve and stabilize the learning speed, based on Nguyen and Widrowpsilas work for MLP networks. The derived equations for weight initialization are based on the study of the behavior of the memory cells output in the hidden layer. To test and evaluate the proposed method, we use a 2-Layered LSTM network to approximate...
The increase of computational power of programmable GPU (graphics processing unit) brings new concepts for using these devices for generic processing. Hence, with the use of the CPU and the GPU for data processing come new ideas that deals with distribution of tasks among CPU and GPU, such as automatic distribution. The importance of the automatic distribution of tasks between CPU and GPU lies in...
Summary form only given. This presentation discusses some key issues based on the objective of finding a viable compromise between the goals of providing an API at a high level of abstraction and meeting the challenges related to target code performance, power consumption, and fault tolerance. We particularly address the question to which degree recent experiences in language design for peta-scale...
Methods of Computational Fluid Dynamics are applied to simulate pulsatile blood flow in human vessels and in the aortic arch. The non-Newtonian behaviour of the human blood is investigated in simple vessels of actual size. Turbulence effects are taken into account. A detailed time-dependent mathematical convergence test has been carried out. The realistic pulsatile flow is used in all simulations...
OOPar is a C++ library which implements an interface to MPI (or other communication library) to offer the user a high level interface for implementing parallel algorithms. Large scale software projects have been parallelized using OOPar and their results will be presented during this presentation. OOPar introduces two concepts to help the programmer in defining a parallel algorithm: Distributed data...
Multi-cores and multi-processors loosely coupled are being considered interesting architectures to increase computational power in many organizations. However, these environments brought a new challenge for the scientific community that can be understood as the limited number of applications developed to take advantage of these new configurations. Opportunistic software environments also need to adapt...
Accuracy of available estimated bandwidth and convergence delay algorithm are researchers' challenges in wireless network measurements. Currently a variety of tools are developed to estimate the end-to-end network available bandwidth such as TOPP (train of packet pair), SLoPS (self loading periodic stream), Spurce and Variable Packet Size etc. These tools are important to improve the QoS (quality...
A mobile ad hoc network (MANET) is a self-configuring network of mobile nodes and is connected by wireless links. In MANET cooperation of nodes for transmitting packets from source to destination cannot be assumed because of the selfish nature of the nodes. The pricing method is one method to provide incentives for the nodes to ensure cooperation. The QoS is of much attention recently due to the bandwidth...
Scientific models are increasingly dependent on processing large volumes of streamed sensing data from a wide range of sensors, from ground based to satellite embarked infrareds. The proliferation, variety and ubiquity of those devices have added new dimensions to the problem of data handling in computational models. This raises several issues, one of which - providing means to access and process...
Classification using association rules has added a new dimension to the ongoing research for accurate classifiers. Over the years, a number of associative classifiers based on positive rules have been proposed in literature. The target of this paper is to improve classification accuracy by using both negative and positive class association rules without sacrificing performance. The generation of negative...
In this work, we present a topology-independent gradient search method for key look up in P2p networks. The approach is inspired in the way ants perceive chemical gradients in their environment to search for food. In our method, a gradient of estimated distances to target keys is created in the network through the propagation of summarized information on contents of peers. During a search, mobile...
It may be difficult to detect the epileptic focus through a simple visual interpretation of ictal and periictal SPECT images, placed side-by-side, especially in patients with extra-temporal or non-localizable intractable epilepsy. Surgery is an important option in the treatment of these epileptic patients. Our methodology aids planning the surgical process. It is a variation of SISCOM methodology...
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