Software systems are growing quickly in needs of functionality, complexity, size and structure. Therefore, it becomes necessary to advance the ways where the software suffers changes, so it can be modified more easily...
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(纸本)9567051070
Software systems are growing quickly in needs of functionality, complexity, size and structure. Therefore, it becomes necessary to advance the ways where the software suffers changes, so it can be modified more easily to accommodate these needs. However, anticipating to the changes is not an easy task, once there are a lot of reasons why systems change. The Laws of Software Evolution describe how a system behaves throughout their successive versions regarding its decaying. Most of the experimental studies supporting these Laws are concerned with legacy systems' source code. However, we believe the Laws can also be observed and applied when dealing with other software development process phases, including evolutive maintenance. Therefore, we present a set of hypotheses to experimentally verify whether the Laws of Software Evolution can also be observed in the object-oriented software. A case study demonstrating the framework's use is also described.
Many current version control systems use a simple data model that is barely sufficient to manipulate source-code. This simple data model is not sufficient to provide versioning capabilities for software modeling envir...
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Mathematical models are often used in system identification applications. The dynamics of most systems, however, change over time and the sources of these changes cannot always be directly determined or measured. To m...
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This paper presents an analysis of the applicability of Sparse Kernel Principal Component Analysis (SKPCA) for feature extraction in speech recognition, as well as, a proposed approach to make the SKPCA technique real...
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Broadband wireless access (BWA) systems offer a solution for broadband access and high data rate transmission of multimedia services with distinct quality-of-service (QoS) requirements through a wireless medium, IEEE ...
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Broadband wireless access (BWA) systems offer a solution for broadband access and high data rate transmission of multimedia services with distinct quality-of-service (QoS) requirements through a wireless medium, IEEE 802.16 standard specifies the PHY and MAC layers for BWA systems. However, in spite of including the possibility for QoS support, the standard does not define how to schedule different types of traffic. This article propose a new MAC protocol for BWA systems that incorporates a traffic scheduling mechanism based on messages and/or stations priorities. An analytical model to evaluate the performance of the proposed protocol is also developed and results obtained for the messages waiting times of different traffic classes are presented.
Many components are usually created within a Domain engineering (DE) process. These components may exchange a great number of messages among them, and many times this interaction occurs within a specific group of comp...
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This paper addresses the dynamic location management for personal communication service (PCS) networks with consideration of mobility patterns. The popular hexagonal cellular architecture is considered. In this paper,...
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The influence of dimension parameters on the performance of Body-surface Laplacian electrodes is studied in this paper. Some rules about the parameter optimization design are presented. The investigation suggests that...
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We present two new systems that approximate probability density functions (pdFs) in order to predict continuous values of time series: the fuzzy multi-hidden Markov predictor (FMHMP) and the multi-hidden Markov model ...
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We present two new systems that approximate probability density functions (pdFs) in order to predict continuous values of time series: the fuzzy multi-hidden Markov predictor (FMHMP) and the multi-hidden Markov model for regression (MHMMR). They use fuzzification or discretization of continuous data and dynamic Bayesian networks (DBN's) to estimate pdfs and then make continuous predictions. A DBN is a Bayesian network that represents a temporal probability model. The employed DBN is a generalization of the hidden Markov model that allows multiple hidden variables. The new systems are applied to the task of monthly electric load single-step forecasting and successfully compared with other fuzzy and discrete probabilistic predictors, two Kalman filter models, and two traditional forecasting methods, Box-Jenkins and Winters exponential smoothing. The employed time series present a sudden significant changing behavior at their last years, as it occurs in an energy rationing.
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