Search for: database
Total 189 records
Article Visual Communications and Image Processing 2005, Beijing, 12 July 2005 through 15 July 2005 ; Volume 5960, Issue 1 , 2005 , Pages 568-575 ; 0277786X (ISSN) ; Kialashaki, N ; Ghonoodi, A ; Soltani, M ; Sharif University of Technology
In content based image retrieval similarity measurement is one of the most important aspects in a large image database for efficient search and retrieval to find the best answer for a user query. Color and texture are among the more expressive of the visual features. Considerable work has been done in designing efficient descriptors for these features for applications such as similarity retrieval. The MPEG-7 specifies a standard set of descriptors for color, texture and shape. In the Human Vision System (HVS), visual information is not perceived equally; some information may be more important than other information. The purpose of this paper is to show how the MPEG-7 descriptor based on...
Article Wec 05: Fourth World Enformatika Conference, Istanbul, 24 June 2005 through 26 June 2005 ; Volume 6 , 2005 , Pages 237-240 ; 9759845857 (ISBN) ; Bagheri Shouraki, S ; Harati Zadeh, S ; Lucas, C ; Ardil C ; Sharif University of Technology
Artificial Life can be used as an agent training approach in large state spaces. This paper presents an artificial life method to increase the training speed of some speech recognizer agents which where previously trained by genetic algorithms. Using this approach, vertical training (genetic mutations and selection) is combined with horizontal training (individual learning through reinforcement learning) and results in a much faster evolution than simple genetic algorithm. The approach is tested and a comparison with GA cases on a standard speech data base is presented. COPYRIGHT © ENFORMATIKA
Article International Journal of Environmental Science and Technology ; Volume 2, Issue 1 , 2005 , Pages 83-96 ; 17351472 (ISSN) ; Vaziri, M ; Sharif University of Technology
In this paper, a different interpretation of sustainable transportation, is introduced, in which sustainability with respect to transportation sector for the selected countries is evaluated. This interpretation characterizes "sustainable development" through "harmonic development". It means sustainable development with special focus on transportation can be measured by the degree of conformity between environment, economy, and social aspects on one hand, and transportation on the other hand. The best indicator to perform such a measurement is elasticity. The database used for the study encompasses a series of national indicators for each country Seventy nine countries were initially selected...
Ph.D. Dissertation Sharif University of Technology ; Jalili, Rasool
Data outsourcing provides cost-saving and availability guarantees. However, privacy and confidentiality issues, disappoint owners from outsourcing their data. Although solutions such as CryptDB and SDB tried to provide secure and practical systems, their enforced limitations, made them useless in practice. Inability in search on encrypted data, is one of the most important existing challenges in such systems. Furthermore, the overhead of mechanisms such as FHEs, removes them from considering for any practical system. Indeed, special purpose encryptions would be the only usable mechanisms for such purposes. However, their limited functionality does not support some important required...
Article Scientia Iranica ; Volume 11, Issue 4 , 2004 , Pages 320-331 ; 10263098 (ISSN) ; Tabatabaee, N ; Kermanshah, M ; Aashtiani, H. Z ; Toobaei, S ; Sharif University of Technology
Sharif University of Technology 2004
The choice of technology to transport passengers in large metropolitan areas is an important issue everywhere. There are many factors involved in this choice. This paper deals with the possibility of the objective use of available information in the analysis of the suitability of a rail public transport system for a city. A database has been made from publications on public city transportation and country level information. Logit models of choice have been calibrated by the maximum likelihood and nonlinear least square methods based on the acquired information. Each city is treated as an "individual", choosing rail or non-rail modes for its trips. Only cities with a population of more than...
Article Scientia Iranica ; Volume 11, Issue 3 , 2004 , Pages 225-233 ; 10263098 (ISSN) ; Nayebi, K ; Sheikhzadeh, H ; Sharif University of Technology
Sharif University of Technology 2004
In this paper, two different statistical approaches are used for duration prediction of the Farsi language. These two statistical models are Neural Networks (NN) and Classification And Regression Trees (CART). The first step in this work was to create a database and develop a flexible feature extraction and selection module. In the next step, the output of the feature selection module was used to train both models. The results of the trained models are further studied to determine the most important parameters affecting the syllable duration in Farsi, The model accuracy is evaluated by using separate training and test data. In the third step of this work, ah automatic rule generator module...
Feature extraction from optimal time-frequency and time-scale transforms for the classification of the knee joint vibroarthrographic signals, Article 3rd IEEE International Symposium on Signal Processing and Information Technology, ISSPIT 2003, 14 December 2003 through 17 December 2003 ; 2003 , Pages 709-712 ; 0780382927 (ISBN); 9780780382923 (ISBN) ; Shamsollahi, M. B ; Rahimi, A ; Behzad, M ; Afkari, P ; Zamani, E. A ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc 2003
In this study knee joint vibroarthrographic (VAG) signals are recorded during active knee movements, which are essentially non-stationary. Because of this nature, common frequency methods are unable to represent the signals, accurately. Both time-frequency and time-scale transforms are used in this research which are good tools for studying non-stationary signals. By optimizing the utilized transforms, it was concluded that the wavelet packet, having the ability of multiresolutional analysis, is a more promising method to extract features from the VAG signals. The performance of different feature extraction techniques were compared by using three new recorded and extensive databases,...
Article 6th International Symposium on Signal Processing and Its Applications, ISSPA 2001, Kuala Lumpur, 13 August 2001 through 16 August 2001 ; Volume 1 , 2001 , Pages 234-237 ; 0780367030 (ISBN); 9780780367036 (ISBN) ; Nayebi, K ; Sharif University of Technology
IEEE Computer Society 2001
This paper presents a multi-stage algorithm for QRS complex classification into normal and abnormal categories using an unsupervised sequential beat clustering and a cross-distance analysis algorithm. After the sequential beat clustering, a search algorithm based on relative similarity of created classes is used to detect the main normal class. Then other classes are labeled based on a distance measurement from the main normal class. Evaluated results on the MIT-BIH ECG database exhibits an error rate less than 1% for normal and abnormal discrimination and 0.2% for clustering of 15 types of arrhythmia existing on the MIT-BIH database. © 2001 IEEE
Presentation and Modeling of a New Nanocomposite Shield Against Gamma Radiation Based on Simulation and Computational Tools, M.Sc. Thesis Sharif University of Technology ; Hosseini, Abolfazl
In this study, using the MCNPX computer code based on the Monte Carlo method, the properties of protection against gamma-rays of the glass system with the combination of (55-x)Bi2O3-15Pb3O4-20Al2O3-10ZnO-xTiO2 with certain concentrations (x= 0, 5, 10, 15, 20, 25, 30 and 35 mol percent) and in nano and micro dimensions by calculating several parameters related to photon attenuation such as half value layer (HVL), Tenth value layer (TVL), mean free range (MFP), mass attenuation coefficient (m), linear attenuation coefficient (l), effective atomic number (Zeff) and buildup factor (BF) for We investigated different energy levels in the range of 1500-100 keV. To verify the simulation results,...