385 research outputs found

    Applications of discrete wavelet transform for feature extraction to increase the accuracy of monitoring systems of liquid petroleum products

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    This paper presents a methodology to monitor the liquid petroleum products which pass through transmission pipes. A simulation setup consisting of an X-ray tube, a detector, and a pipe was established using a Monte Carlo n-particle X-version transport code to investigate a two-by-two mixture of four different petroleum products, namely, ethylene glycol, crude oil, gasoline, and gasoil, in deferent volumetric ratios. After collecting the signals of each simulation, discrete wavelet transform (DWT) was applied as the feature extraction system. Then, the statistical feature, named the standard deviation, was calculated from the approximation of the fifth level, and the details of the second to fifth level provide appropriate inputs for neural network training. Three multilayer perceptron neural networks were utilized to predict the volume ratio of three types of petroleum products, and the volume ratio of the fourth product could easily be obtained from the results of the three presented networks. Finally, a root mean square error of less than 1.77 was obtained in predicting the volume ratio, which was much more accurate than in previous research. This high accuracy was due to the use of DWT for feature extraction

    Klasifikasi Menggunakan Metode Hybrid Bayessian-Neural Network (Studi Kasus: Identifikasi Virus Komputer)

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    Virus komputer merupakan suatu program yang menginfeksi komputer terutama pada saat komputer sedang beroperasi dan menjadi momok bagi pengguna komputer. Virus komputer dapat menggandakan dirinya sendiri dan menyebar dengan cara menyisipkan dirinya pada program dan data lainnya. Efek negatif virus komputer adalah memperbanyak dirinya sendiri, yang membuat sumber daya pada komputer terutama penggunaan memori menjadi berkurang secara signifikan. Diperlukan suatu penangkal atau antivirus dalam mencegah penyebaran yang lebih jauh dalam sistem komputer. Pada penelitian ini, dilakukan suatu identifikasi virus dengan menggabungkan dua metode yaitu Naïve Bayes Classifier dengan Neural Network. Fitur virus didapatkan dari mengkodekan ciri-ciri dari virus. Untuk klasifikasi awal digunakan metode Naïve Bayes Classifier untuk membagi dua jenis fitur, yaitu virus dan bukan virus. Setelah masuk kedalam jenis virus, maka diklasifikasikan kedalam dua jenis virus yaitu trojan atau worm menggunakan salah satu metode neural network (perceptron). Hasil sistem setelah dilakukan uji coba didapatkan recognition rate tertinggi yaitu sebesar 94.12%

    Klasifikasi Menggunakan Metode Hybrid Bayessian-Neural Network (Studi Kasus: Identifikasi Virus Komputer)

    Get PDF
    Virus komputer merupakan suatu program yang menginfeksi komputer terutama pada saat komputer sedang beroperasi dan menjadi momok bagi pengguna komputer. Virus komputer dapat menggandakan dirinya sendiri dan menyebar dengan cara menyisipkan dirinya pada program dan data lainnya. Efek negatif virus komputer adalah memperbanyak dirinya sendiri, yang membuat sumber daya pada komputer terutama penggunaan memori menjadi berkurang secara signifikan. Diperlukan suatu penangkal atau antivirus dalam mencegah penyebaran yang lebih jauh dalam sistem komputer. Pada penelitian ini, dilakukan suatu identifikasi virus dengan menggabungkan dua metode yaitu Naïve Bayes Classifier dengan Neural Network. Fitur virus didapatkan dari mengkodekan ciri-ciri dari virus. Untuk klasifikasi awal digunakan metode Naïve Bayes Classifier untuk membagi dua jenis fitur, yaitu virus dan bukan virus. Setelah masuk kedalam jenis virus, maka diklasifikasikan kedalam dua jenis virus yaitu trojan atau worm menggunakan salah satu metode neural network (perceptron). Hasil sistem setelah dilakukan uji coba didapatkan recognition rate tertinggi yaitu sebesar 94.12%

    Forecasting carbon price using empirical mode decomposition and evolutionary least squares support vector regression

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    Conventional methods are less robust in terms of accurately forecasting non-stationary and nonlineary carbon prices. In this study, we propose an empirical mode decomposition-based evolutionary least squares support vector regression multiscale ensemble forecasting model for carbon price forecasting. Firstly, each carbon price is disassembled into several simple modes with high stability and high regularity via empirical mode decomposition. Secondly, particle swarm optimization-based evolutionary least squares support vector regression is used to forecast each mode. Thirdly, the forecasted values of all the modes are composed into the ones of the original carbon price. Finally, using four different-matured carbon futures prices under the European Union Emissions Trading Scheme as samples, the empirical results show that the proposed model is more robust than the other popular forecasting methods in terms of statistical measures and trading performances

    Forecasting carbon prices in the Shenzhen market, China:The role of mixed-frequency factors

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    In this study, the hybrid of combination-mixed data sampling regression model and back propagation neural network (combination-MIDAS-BP) is proposed to perform real-time forecasting of weekly carbon prices in China's Shenzhen carbon market. In addition to daily energy, economy and weather conditions, environmental factor is introduced into predictive indicators. The empirical results show that the carbon price is more sensitive to coal, temperature and AQI (air quality index) than to other factors. It is also shown that the forecast accuracy of the proposed model is approximately 30% and 40% higher than that of combination-MIDAS models and benchmark models, respectively. Given these forecast results, China's government and enterprises can effectively manage nonlinear, nonstationary, and irregular carbon prices, providing a better investing and managing tool from behavioural economics. (C) 2019 Elsevier Ltd. All rights reserved

    Soft computing for tool life prediction a manufacturing application of neural - fuzzy systems

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    Tooling technology is recognised as an element of vital importance within the manufacturing industry. Critical tooling decisions related to tool selection, tool life management, optimal determination of cutting conditions and on-line machining process monitoring and control are based on the existence of reliable detailed process models. Among the decisive factors of process planning and control activities, tool wear and tool life considerations hold a dominant role. Yet, both off-line tool life prediction, as well as real tune tool wear identification and prediction are still issues open to research. The main reason lies with the large number of factors, influencing tool wear, some of them being of stochastic nature. The inherent variability of workpiece materials, cutting tools and machine characteristics, further increases the uncertainty about the machining optimisation problem. In machining practice, tool life prediction is based on the availability of data provided from tool manufacturers, machining data handbooks or from the shop floor. This thesis recognises the need for a data-driven, flexible and yet simple approach in predicting tool life. Model building from sample data depends on the availability of a sufficiently rich cutting data set. Flexibility requires a tool-life model with high adaptation capacity. Simplicity calls for a solution with low complexity and easily interpretable by the user. A neural-fuzzy systems approach is adopted, which meets these targets and predicts tool life for a wide range of turning operations. A literature review has been carried out, covering areas such as tool wear and tool life, neural networks, frizzy sets theory and neural-fuzzy systems integration. Various sources of tool life data have been examined. It is concluded that a combined use of simulated data from existing tool life models and real life data is the best policy to follow. The neurofuzzy tool life model developed is constructed by employing neural network-like learning algorithms. The trained model stores the learned knowledge in the form of frizzy IF-THEN rules on its structure, thus featuring desired transparency. Low model complexity is ensured by employing an algorithm which constructs a rule base of reduced size from the available data. In addition, the flexibility of the developed model is demonstrated by the ease, speed and efficiency of its adaptation on the basis of new tool life data. The development of the neurofuzzy tool life model is based on the Fuzzy Logic Toolbox (vl.0) of MATLAB (v4.2cl), a dedicated tool which facilitates design and evaluation of fuzzy logic systems. Extensive results are presented, which demonstrate the neurofuzzy model predictive performance. The model can be directly employed within a process planning system, facilitating the optimisation of turning operations. Recommendations aremade for further enhancements towards this direction
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