Search for: database-systems
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    World city mode choice: Choice of rail public transportation

    , Article Scientia Iranica ; Volume 11, Issue 4 , 2004 , Pages 320-331 ; 10263098 (ISSN) Poorzahedy, H ; 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... 

    Syllable duration prediction for Farsi text-to-speech systems

    , Article Scientia Iranica ; Volume 11, Issue 3 , 2004 , Pages 225-233 ; 10263098 (ISSN) Nazari, B ; 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... 

    Randomized algorithms for comparison-based search

    , Article Advances in Neural Information Processing Systems 24: 25th Annual Conference on Neural Information Processing Systems 2011, NIPS 2011, 12 December 2011 through 14 December 2011 ; December , 2011 ; 9781618395993 (ISBN) Tschopp, D ; Diggavi, S ; Delgosha, P ; Mohajer, S ; Sharif University of Technology
    This paper addresses the problem of finding the nearest neighbor (or one of the R-nearest neighbors) of a query object q in a database of n objects, when we can only use a comparison oracle. The comparison oracle, given two reference objects and a query object, returns the reference object most similar to the query object. The main problem we study is how to search the database for the nearest neighbor (NN) of a query, while minimizing the questions. The difficulty of this problem depends on properties of the underlying database. We show the importance of a characterization: combinatorial disorder D which defines approximate triangle inequalities on ranks. We present a lower bound of Ω(Dlog... 

    Automatic access control based on face and hand biometrics in a non-cooperative context

    , Article Proceedings - 2018 IEEE Winter Conference on Applications of Computer Vision Workshops, WACVW 2018 ; Volume 2018-January , 2018 , Pages 28-36 ; 9781538651889 (ISBN) Sabet Jahromi, M. N ; Bonderup, M. B ; Asadi Aghbolaghi, M ; Avots, E ; Nasrollahi, K ; Escalera, S ; Kasaei, S ; Moeslund, T. B ; Anbarjafari, G ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2018
    Automatic access control systems (ACS) based on the human biometrics or physical tokens are widely employed in public and private areas. Yet these systems, in their conventional forms, are restricted to active interaction from the users. In scenarios where users are not cooperating with the system, these systems are challenged. Failure in cooperation with the biometric systems might be intentional or because the users are incapable of handling the interaction procedure with the biometric system or simply forget to cooperate with it, due to for example, illness like dementia. This work introduces a challenging bimodal database, including face and hand information of the users when they... 

    Assessment of modal transportation sustainability: Application of data envelopment and concordance analyses

    , Article Iranian Journal of Science and Technology, Transaction B: Engineering ; Volume 31, Issue 2 , 2007 , Pages 179-193 ; 03601307 (ISSN) Rassafi, A. A ; Vaziri, M ; Sharif University of Technology
    This study tries to characterize national transportation modes to assess balancing and sustainability. Using a pioneer measure for sustainable development (SD), and based on the conformity of the growths of all sectors with transportation modes, the countries are comparatively studied. The proposed measure, elasticity, for each pair of variables indicates the extent to which the two variables have been changing consistently. Indeed the elasticity values are measures of "harmonic development" reflecting sustainability. The study database consisted of key aspects of transportation sustainability in the form of national variables including transportation, economic, social and environmental... 

    DotGrid: A.NET-based infrastructure for global Grid computing

    , Article 6th IEEE International Symposium on Cluster Computing and the Grid, 2006. CCGRID 06, 16 May 2006 through 19 May 2006 ; 2006 ; 0769525857 (ISBN); 9780769525853 (ISBN) Poshtkuhi, A ; Abutalebi, A. H ; Ayough, L. M ; Hessabi, S ; Sharif University of Technology
    IEEE Computer Society  2006
    Recently, Grid infrastructures have provided wide integrated use of resources. DotGrid intends to introduce required Grid services and toolkits that are implemented as a layer wrapped over the existing operating systems. Our DotGrid has been developed based on Microsoft .NET in Windows and MONO .NET in Linux and UNIX. Using DotGrid APIs, Grid middlewares and applications can be implemented easily. We evaluated our DotGrid capabilities by implementing some applications including a grid-based distributed cryptographic engine and also a typical computational problem. © 2006 IEEE  

    A new approach in object-oriented methodology for creating event-based simulator

    , Article 2006 Canadian Conference on Electrical and Computer Engineering, CCECE'06, Ottawa, ON, 7 May 2006 through 10 May 2006 ; 2006 , Pages 2424-2427 ; 08407789 (ISSN); 1424400384 (ISBN); 9781424400386 (ISBN) Aliakbarian, S ; Abdollahzadeh, A ; Jalali, L ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2006
    This paper explores software design methodologies in the context of creating a simulator and proposes a methodology to design and implement an event-based simulator namely Sim Met. SimMet is explored in the context of the development of a complex simulator for simulating real world conditions to use in science, technology and medicine and other simulations. In this paper we interested in event-based approach to create a real world with variety range of event possibilities. The paper first discusses the role of time concept as the cornerstone of a methodical analysis and design phase. In Sim Met we use an adaptation of object-oriented methodology to meet time and event concepts in creating a... 

    DBMSS: An event-based simulator for analyzing concurrency protocols in database systems

    , Article 2006 Canadian Conference on Electrical and Computer Engineering, CCECE'06, Ottawa, ON, 7 May 2006 through 10 May 2006 ; 2006 , Pages 1874-1877 ; 08407789 (ISSN); 1424400384 (ISBN); 9781424400386 (ISBN) Jalali, L ; Abdollahzadeh, A ; Aliakbarian, S ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2006
    This paper explores design and implementation of an event-based simulator namely DBMSS for analyzing concurrency protocols in database systems. In the design of DBMSS we interested in event-based approach to create a real world with variety range of event possibilities. DBMSS is explored in the context of the development of a complex simulator for simulating real world conditions and provide an event-based environment to test and evaluate concurrency protocols in database systems. First we discuss the architecture of DBMSS and use it to provide arrival transactions to test and evaluate concurrency protocols in database system. We present the comparison of 4 concurrency protocols in variety... 

    A novel fuzzy approach to speech recognition

    , Article Proceedings - HIS'04: 4th International Conference on Hybrid Intelligent Systems, Kitakyushu, 5 December 2004 through 8 December 2004 ; 2005 , Pages 340-345 ; 0769522912 (ISBN) Halavati, R ; Shouraki, S.B ; Eshraghi, M ; Alemzadeh, M ; Ziaie, P ; Ishikawa M ; Hashimoto S ; Paprzycki M ; Barakova E ; Yoshida K ; Koppen M ; Corne D.M ; Abraham A ; Sharif University of Technology
    This paper presents a novel approach to speech recognition using fuzzy modeling. The task begins with conversion of speech spectrogram into a linguistic description based on arbitrary colors and lengths. While phonemes are also described using these fuzzy measures, and recognition is done by normal fuzzy reasoning, a genetic algorithm optimizes phoneme definitions so that to classify samples into correct phonemes. The method is tested over a standard speech data base and the results are presented. © 2005 IEEE  

    A novel fuzzy approach to recognition of online persian handwriting

    , Article 5th International Conference on Intelligent Systems Design and Applications, ISDA '05, Wroclaw, 8 September 2005 through 10 September 2005 ; Volume 2005 , 2005 , Pages 268-273 ; 0769522866 (ISBN); 9780769522869 (ISBN) Baghshah, M. S ; Shouraki, S. B ; Kasaei, S ; Sharif University of Technology
    Fuzzy logic has proved to be a powerful tool to represent imprecise and irregular patterns. This paper presents a novel fuzzy approach for recognizing online Persian (Farsi) handwriting which is also useful for multi-writer environments. In this approach, the representation of handwriting parameters is accomplished by fuzzy linguistic modeling. The representative features are selected to describe the shape of tokens. Fuzzy linguistic terms provide robustness against handwriting variations. The purposed method was run on a database of Persian isolated handwritten characters and achieved a relatively high recognition rate. © 2005 IEEE  

    Evolution of speech recognizer agents by artificial life

    , Article Wec 05: Fourth World Enformatika Conference, Istanbul, 24 June 2005 through 26 June 2005 ; Volume 6 , 2005 , Pages 237-240 ; 9759845857 (ISBN) Halavati, R ; 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  

    SFAVD: Sharif farsi audio visual database

    , Article IKT 2013 - 2013 5th Conference on Information and Knowledge Technology, Shiraz, Iran ; 2013 , Pages 417-421 ; 9781467364904 (ISBN) Naraghi, Z ; Jamzad, M ; Sharif University of Technology
    With increasing use of computers in everyday life, improved communication between machines and human is needed. To make a right communication and understand a humankind face which is made in a graphical environment, implementing the audio and visual projects like lip reading, audio and visual speech recognition and lip making are needed. Lack of a complete audio and visual database for this application in Farsi language made us provide a new complete Farsi database for this project that is called SFAVD. It is a unique audio and visual database which in addition to considering Farsi conceptual and speech structure, it considers influence of speech on lip changes. This database is created for... 

    Correctness verification in database outsourcing: A trust-based fake tuples approach

    , Article Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) ; Volume 7671 LNCS , 2012 , Pages 343-351 ; 03029743 (ISSN) ; 9783642351297 (ISBN) Ghasemi, S ; Noferesti, M ; Hadavi, M. A ; Nogoorani, S. D ; Jalili, R ; Sharif University of Technology
    An important security challenge in database outsourcing scenarios is the correctness verification of query results. The proposed approaches in the literature, impose high overhead on both the service provider and specially the clients. In this paper, we propose the Trust-Based Fake Tuples approach to audit the correctness of query results. In this approach, some fake tuples are included among the real ones in order to verify the correctness of the results. The experience learnt from past results is used in this paper to evaluate the trust toward the service provider. This trust value is used to tune the number of fake tuples and subsequently the imposed overhead. As the trust value toward... 

    Improve the classification and sales management of products using multi-relational data mining

    , Article 2011 IEEE 3rd International Conference on Communication Software and Networks, ICCSN 2011, Xi'an, 27 May 2011 through 29 May 2011 ; 2011 , Pages 329-337 ; 9781612844855 (ISBN) Houshmand, M ; Alishahi, M ; Sharif University of Technology
    There are some elements such as competition among companies and changes in demands which result in changes of customers' behaviors. Therefore, paying no attention to these changes may lead to a reduction in company benefits and loss of customers. Since data and their analyses determine the activities and decision makings of companies, data quality is of paramount in analyzing them because misinformation leads to wrong decision making. Since data mining has been designed to find out multi repetition patterns, it can be used to improve the product sales violations by sales people and increase the quality of data. Most of data mining models available try to find patterns in one table, but the... 

    Towards an architecture for real-time data storage

    , Article Proceedings - 2nd International Conference on Computational Intelligence, Modelling and Simulation, CIMSim 2010, 28 September 2010 through 30 September 2010 ; 2010 , Pages 279-284 ; 9780769542621 (ISBN) Yektamanesh, O ; Habibi, J ; Ahmadi, H ; Vatanian Shanjani, G ; Sharif University of Technology
    Nowadays, due to the growing role that analytical, predictive and decision making activities perform in organizations, organizational data are very important. In order to utilizing organizational data, it should be transmitted from the operational and transactional environment to a dimensional or normal database. However, not only differences in platforms and data types are some issues that should be overcome, but also variety of data types such as non-structural and text format files should be considered. In this way, exploiting updated data storages is necessary for quick and accurate services and raising customers' satisfaction. Although real time data storages are frequently used in... 

    A novel method to find appropriate ε for DBSCAN

    , Article Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), 24 March 2010 through 26 March 2010 ; Volume 5990 LNAI, Issue PART 1 , 2010 , Pages 93-102 ; 03029743 (ISSN) ; 3642121446 (ISBN) Esmaelnejad, J ; Habibi, J ; Hassas Yeganeh, S ; Sharif University of Technology
    Clustering is one of the most useful methods of data mining, in which a set of real or abstract objects are categorized into clusters. The DBSCAN clustering method, one of the most famous density based clustering methods, categorizes points in dense areas into same clusters. In DBSCAN a point is said to be dense if the ε-radius circular area around it contains at least MinPts points. To find such dense areas, region queries are fired. Two points are defined as density connected if the distance between them is less than ε and at least one of them is dense. Finally, density connected parts of the data set extracted as clusters. The significant issue of such a method is that its parameters (ε... 

    Quantization-unaware double JPEG compression detection

    , Article Journal of Mathematical Imaging and Vision ; Volume 54, Issue 3 , 2016 , Pages 269-286 ; 09249907 (ISSN) Taimori, A ; Razzazi, F ; Behrad, A ; Ahmadi, A ; Babaie Zadeh, M ; Sharif University of Technology
    Springer New York LLC 
    The current double JPEG compression detection techniques identify whether or not an JPEG image file has undergone the compression twice, by knowing its embedded quantization table. This paper addresses another forensic scenario in which the quantization table of a JPEG file is not explicitly or reliably known, which may compel the forensic analyst to blindly reveal the recompression clues. To do this, we first statistically analyze the theory behind quantized alternating current (AC) modes in JPEG compression and show that the number of quantized AC modes required to detect double compression is a function of both the image’s block texture and the compression’s quality level in a fresh... 

    Characterizing the rate-memory tradeoff in cache networks within a factor of 2

    , Article IEEE Transactions on Information Theory ; 2018 ; 00189448 (ISSN) Yu, Q ; Maddah Ali, M. A ; Avestimehr, A. S ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2018
    We consider a basic caching system, where a single server with a database of N files (e.g. movies) is connected to a set of K users through a shared bottleneck link. Each user has a local cache memory with a size of M files. The system operates in two phases. a placement phase, where each cache memory is populated up to its size from the database, and a following delivery phase, where each user requests a file from the database, and the server is responsible for delivering the requested contents. The objective is to design the two phases to minimize the load (peak or average) of the bottleneck link. We characterize the rate-memory tradeoff of the above caching system within a factor of... 

    The exact rate-memory tradeoff for caching with uncoded prefetching

    , Article IEEE Transactions on Information Theory ; Volume 64, Issue 2 , 2018 , Pages 1281-1296 ; 00189448 (ISSN) Yu, Q ; Maddah Ali, M. A ; Avestimehr, A. S ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2018
    We consider a basic cache network, in which a single server is connected to multiple users via a shared bottleneck link. The server has a database of files (content). Each user has an isolated memory that can be used to cache content in a prefetching phase. In a following delivery phase, each user requests a file from the database, and the server needs to deliver users' demands as efficiently as possible by taking into account their cache contents. We focus on an important and commonly used class of prefetching schemes, where the caches are filled with uncoded data. We provide the exact characterization of the rate-memory tradeoff for this problem, by deriving both the minimum average rate... 

    Knowledge discovery using a new interpretable simulated annealing based fuzzy classification system

    , Article Proceedings - 2009 1st Asian Conference on Intelligent Information and Database Systems, ACIIDS 2009, 1 April 2009 through 3 April 2009, Dong Hoi ; 2009 , Pages 271-276 ; 9780769535807 (ISBN) Mohamadia, H ; Habibib, J ; Moavena, S ; Sharif University of Technology
    This paper presents a new interpretable fuzzy classification system. Simulated annealing heuristic is employed to effectively investigate the large search space usually associated with classification problem. Here, two criteria are used to evaluate the proposed method. The first criterion is accuracy of extracted fuzzy if-then rules, and the other is comprehensibility of obtained rules. Experiments are performed with some data sets from UCI machine learning repository. Results are compared with several well-known classification algorithms, and show that the proposed approach provides more accurate and interpretable classification system. © 2009 IEEE