Loading...
Search for:
information-retrieval
0.007 seconds
Total 81 records
Using tree kernels for classifying temporal relations between events
, Article PACLIC 23 - Proceedings of the 23rd Pacific Asia Conference on Language, Information and Computation, 3 December 2009 through 5 December 2009 ; Volume 1 , 2009 , Pages 355-364 ; 9789624423198 (ISBN) ; Ghassem Sani, G. R ; Khayyamian, M ; Sharif University of Technology
Abstract
The ability to accurately classify temporal relations between events is an important task in a large number of natural language processing and text mining applications such as question answering, summarization, and language specific information retrieval. In this paper, we propose an improved way of classifying temporal relations, using support vector machines (SVM). Along with gold-standard corpus features, the proposed method aims at exploiting useful syntactic features, which are automatically generated, to improve accuracy of the SVM classification method. Accordingly, a number of novel kernel functions are introduced and evaluated for temporal relation classification. Our evaluations...
Freshness of web search engines: Improving performance of web search engines using data mining techniques
, Article International Conference for Internet Technology and Secured Transactions, ICITST 2009, 9 November 2009 through 12 November 2009, London ; 2009 ; 9781424456482 (ISBN) ; Farahmand Nejad, A ; Abolhassani, H ; Sharif University of Technology
Abstract
Progressive use of Web based information retrieval systems such as general purpose search engines and dynamic nature of the Web make it necessary to continually maintain Web based information retrieval systems. Crawlers facilitate this process by following hyperlinks in Web pages to automatically download new and updated Web pages. Freshness (recency) is one of the important maintaining factors of Web search engine crawlers that takes weeks to months. Many large Web crawlers start from seed pages, fetch every links from them, and continually repeat this process without any policies that help them to better crawling and improving performance of those. We believe that data mining techniques...
Enhancing Recommender Systems Using Analysis of Groups' Influence on Users in Social Networks
, M.Sc. Thesis Sharif University of Technology ; Habibi, Jafar (Supervisor)
Abstract
Rapid growth in science and technology has created vast diversity in products, services and needs of people and groups. As the Internet and web technologies have progressed, a web-based solution to explore products of either a specific domain or multiple domains is mandatory. One of the main challenges in these systems is learning users’ preferences to recommend items possibly interesting to the user. Social network of the users is one of the sources that can inject additional information about them which can be exploited to improve accuracy of the system. Depending on the method, the performance, accuracy and personalization may differ .One of the most popular methods to extract this...
Music Emotion Recognition
, M.Sc. Thesis Sharif University of Technology ; Sameti, Hossein (Supervisor)
Abstract
Measuring emotions of music is one of the methods to determine music content. Music emotion detection is applicable in music retrieval, recognition of music genre and also music data management softwares. Music emotion is considered in different sciences such as physiology, psychology, musicology and engineering. First, we collected a database of different types of music with various emotions. These data have been labeled according to their emotions. In this project, four emotions (Angry, happy, relax and sad) have been used as labels based on Thayer’s two dimension emotion model. There are two basic steps for music emotion recognition similar to other recognition systems: Feature extraction...
A fuzzy learning model for retrieving and learning information in visual working brain memory mechanism
, Article 2017 25th Iranian Conference on Electrical Engineering, ICEE 2017, 2 May 2017 through 4 May 2017 ; 2017 , Pages 61-64 ; 9781509059638 (ISBN) ; Bagheri Shouraki, S ; Jahed, M ; Sharif University of Technology
Abstract
In this investigation, the idea of Visual Working Memory (VWM) mechanism modeling based on versatile fuzzy method; Active Learning method, is presented. Visual information process; retrieving and learning rely on the use of Ink Drop Spread (IDS) and Center of Gravity (COG) as spatial density convergence operators. IDS modeling is characterized by processing that uses intuitive pattern information instead of complex formulas, and it is capable of stable and fast convergence. Furthermore, because it approves that distortion in retrieving irrelative data is adaptive to avoid storing lots of repetitive external information in daily visualization. Subsequently, this distortion is analyzed via two...
Rate-power-interference optimization in underlay OFDMA CRNs with imperfect CSI
, Article IEEE Communications Letters ; Volume 21, Issue 7 , 2017 , Pages 1657-1660 ; 10897798 (ISSN) ; Musavian, L ; Ng, D. W. K ; Sharif University of Technology
Abstract
Achieving higher transmission rate while reducing transmission power and induced interference on neighboring receivers is deemed necessary for the advancement of future generation networks and is particularly challenging, since these directions could be conflicting in nature. This letter adopts a multiobjective optimization (MOOP) approach to settle the tradeoffs between these three conflicting objectives in orthogonal frequency-division multiple access-based cognitive radio networks. Besides, unlike most of the work in the literature that studied the imperfect channel side information (CSI) of the link between the secondary transmitter and the primary receiver to evaluate ergodic capacity,...
Cluster-based sparse topical coding for topic mining and document clustering
, Article Advances in Data Analysis and Classification ; 2017 , Pages 1-22 ; 18625347 (ISSN) ; Gholampour, I ; Tabandeh, M ; Sharif University of Technology
Abstract
In this paper, we introduce a document clustering method based on Sparse Topical Coding, called Cluster-based Sparse Topical Coding. Topic modeling is capable of improving textual document clustering by describing documents via bag-of-words models and projecting them into a topic space. The latent semantic descriptions derived by the topic model can be utilized as features in a clustering process. In our proposed method, document clustering and topic modeling are integrated in a unified framework in order to achieve the highest performance. This framework includes Sparse Topical Coding, which is responsible for topic mining, and K-means that discovers the latent clusters in documents...
RedQueen: an online algorithm for smart broadcasting in social networks
, Article WSDM 2017 - Proceedings of the 10th ACM International Conference on Web Search and Data Mining, 2 February 2017 ; 2017 , Pages 51-60 ; 9781450346757 (ISBN) ; Upadhyay, U ; Rabiee, H. R ; Gomez Rodriguez, M ; Sharif University of Technology
Association for Computing Machinery, Inc
2017
Abstract
Users in social networks whose posts stay at the top of their followers' feeds the longest time are more likely to be noticed. Can we design an online algorithm to help them decide when to post to stay at the top? In this paper, we address this question as a novel optimal control problem for jump stochastic differential equations. For a wide variety of feed dynamics, we show that the optimal broadcasting intensity for any user is surprisingly simple - it is given by the position of her most recent post on each of her follower's feeds. As a consequence, we are able to develop a simple and highly efficient online algorithm, RedQueen, to sample the optimal times for the user to post....
A generalized audio identification system using adaptive filters
, Article 26th Iranian Conference on Electrical Engineering, ICEE 2018, 8 May 2018 through 10 May 2018 ; 2018 , Pages 1641-1646 ; 9781538649169 (ISBN) ; Sameti, H ; Alidoust, A ; Sharif University of Technology
Abstract
From searching music with smartphones to broadcast monitoring by radio channels, audio identification systems are being used more in recent years. Design of such systems may differ when the problem domain changes, since each environment has special conflicting constraints to consider, like required speed and robustness to signal degradations. In this paper, a widely used audio identification system originally developed by Haitsma and Kalker is analyzed from a signal processing point of view and the fingerprint (audio feature) extraction method is modified. By adding a flexible filter to the fingerprint extraction method, the original system can be tuned to work in different domains. In order...
Cluster-based sparse topical coding for topic mining and document clustering
, Article Advances in Data Analysis and Classification ; Volume 12, Issue 3 , 2018 , Pages 537-558 ; 18625347 (ISSN) ; Gholampour, I ; Tabandeh, M ; Sharif University of Technology
Springer Verlag
2018
Abstract
In this paper, we introduce a document clustering method based on Sparse Topical Coding, called Cluster-based Sparse Topical Coding. Topic modeling is capable of improving textual document clustering by describing documents via bag-of-words models and projecting them into a topic space. The latent semantic descriptions derived by the topic model can be utilized as features in a clustering process. In our proposed method, document clustering and topic modeling are integrated in a unified framework in order to achieve the highest performance. This framework includes Sparse Topical Coding, which is responsible for topic mining, and K-means that discovers the latent clusters in documents...
Towards side channel secure cyber-physical systems
, Article CSI International Symposium on Real-Time and Embedded Systems and Technologies, RTEST 2018, 9 May 2018 through 10 May 2018 ; 9-10 May , 2018 , Pages 31-38 ; 9781538614754 (ISBN) ; Afandizadeh Zargari, A. H ; Farzam, S. M. H ; Bayat Sarmadi, S ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2018
Abstract
Cyber-physical systems contain networked embedded systems. Such systems may implement cryptographic algorithms for processing and/or communication. Therefore, they can be prone to side-channel attacks. Differential power analysis is one of such attacks, which is considered among the most serious threats against cryptographic devices. Various metrics have been proposed to evaluate the resistance of different implementations against these attacks. Some of these metrics need side-channel attacks to be conducted and depend on the considered power model. Due to the vast variety of proposed side-channel attacks and power models, comprehensively evaluating a design under these metrics is commonly...
Duality in bipolar triangular fuzzy number quadratic programming problems
, Article Proceedings of the International Conference on Intelligent Sustainable Systems, ICISS 2017, 7 December 2017 through 8 December 2017 ; 19 June , 2018 , Pages 1236-1238 ; 9781538619599 (ISBN) ; Ghanbari, R ; Mahdavi Amiri, N ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2018
Abstract
We discuss how to solve bipolar fuzzy quadratic programming problems, where the parameters are bipolar triangular fuzzy numbers, making use of linear ranking functions. Also, we explore some duality properties of bipolar triangular fuzzy number quadratic programming problem (BTFNQPP). © 2017 IEEE
-
, Article 2018 Iran Workshop on Communication and Information Theory, IWCIT 2018, 25 April 2018 through 26 April 2018 ; 2018 , Pages 1-6 ; 9781538641491 (ISBN) ; Maddah Ali, M. A ; Sharif University of Technology
Institute of electrical and electronics engineers Inc
2018
Abstract
The widespread use of cloud computing services raises the question of how one can delegate the processing tasks to the untrusted distributed parties without breaching the privacy of its data and algorithms. Motivated by the algorithm privacy concerns in a distributed computing system, in this paper, we introduce the private function retrieval (PFR) problem, where a user wishes to efficiently retrieve a linear function of K messages from N non-communicating replicated servers while keeping the function hidden from each individual server. The goal is to find a scheme with minimum communication cost. To characterize the fundamental limits of the communication cost, we define the capacity of PFR...
Content based image retrieval using the knowledge of texture, color and binary tree structure
, Article 2009 Canadian Conference on Electrical and Computer Engineering, CCECE '09, St. Johns, NL, 3 May 2009 through 6 May 2009 ; 2009 , Pages 999-1003 ; 08407789 (ISSN); 9781424435081 (ISBN) ; Jamzad, M ; Sharif University of Technology
2009
Abstract
Content base image retrieval is an important research field with many applications. In this paper we presents a new approach for finding similar images to a given query, in a general-purpose image database using content-based image retrieval. Color and texture are used as basic features to describe images. In addition, a binary tree structure is used to describe higher level features of an image. It has been used to keep information about separate segments of the images. The performance of the proposed system has been compared with the SIMPLIcity system using COREL image database. Our experimental results showed that among 10 image categories available in COREL database, our system had a...
On the uniform sampling of the web: An improvement on bucket based sampling
, Article 2009 International Conference on Communication Software and Networks, ICCSN 2009, Macau, 27 February 2009 through 28 February 2009 ; 2009 , Pages 205-209 ; 9780769535227 (ISBN) ; Mousavi, H ; Movaghar, A ; Sharif University of Technology
2009
Abstract
Web is one of the biggest sources of information. The tremendous size, the dynamicity, and the structure of the Web have made the information retrieval process of the web a challenging issue. Web Search Engines (WSEs) have started to help users with this matter. However, these types of application, to perform more effectively, always need current information about many characteristics of the Web. To determine these characteristics, one way is to use statistical sampling of the Web pages. In this kind of approaches, instead of analyzing a large number of Web pages, a rather smaller and more uniform set of Web pages is used. This research attempts to analyze the presented methods for...
Harmony K-means algorithm for document clustering
, Article Data Mining and Knowledge Discovery ; Volume 18, Issue 3 , 2009 , Pages 370-391 ; 13845810 (ISSN) ; Abolhassani, H ; Sharif University of Technology
2009
Abstract
Fast and high quality document clustering is a crucial task in organizing information, search engine results, enhancing web crawling, and information retrieval or filtering. Recent studies have shown that the most commonly used partition-based clustering algorithm, the K-means algorithm, is more suitable for large datasets. However, the K-means algorithm can generate a local optimal solution. In this paper we propose a novel Harmony K-means Algorithm (HKA) that deals with document clustering based on Harmony Search (HS) optimization method. It is proved by means of finite Markov chain theory that the HKA converges to the global optimum. To demonstrate the effectiveness and speed of HKA, we...
Design and Implementation of a Search Engine for Sample Applications of Object-Oriented Framework-Provided Concepts
, M.Sc. Thesis Sharif University of Technology ; Heydarnoori, Abbas (Supervisor)
Abstract
An object-oriented application framework, like Eclipse, not only provides a framework for designing and implementing new applications, but also decreases the time and the cost of developing new software applications. Moreover, theseframeworks increase the maintainability of software systems. Therefore, their popularity is on the rise. The main problem of using object-oriented application frameworks is the lack of proper documentations and guides. Thus, developers often try to learn how to implement their desired concepts (e.g., Context Menu) from available sample applications. This leads the programmers to another problem which is finding the sample applications. Finding a proper sample...
Temporal Relation Extraction of Persian Texts by Learning Methods
, M.Sc. Thesis Sharif University of Technology ; Ghasem Sani, Gholamreza (Supervisor)
Abstract
To fully understanding a text written in a natural language, we need to comprehend the events within that text. Temporal relation extraction always have been one of the main challenges in natural language processing in semantic level. Temporal relation extraction makes the understanding and interpretation of text easier and the extracted information can be used in many natural language systems like question answering, summarization, and information retrieval systems. Early researches on temporal relation extraction was mainly on English and limited to rule based systems. However, with extending the English corpora and availability of temporal corpora in other languages, more attention has...
Data Recovery Analysis of Real-Time Sensor Networks
, M.Sc. Thesis Sharif University of Technology ; Jahangir, Amir Hossein (Supervisor)
Abstract
There are several applications of wireless sensor networks wherein the data collected by the sensors in the network are critical and hence have to be reliably transported to the sink, example of such applications are fire detection in a forest or controlling vibration on body of dam. Reliable communication in wireless sensor networks is hard to achieve efficiently using methods in conventional systems like Internet. End-to-end retransmission is inefficient, or in some cases impossible. It is well-known that Reed-Solomon codes may be used to provide error correction for multiple failures in RAID-like systems. To the coding theorists, this technique is a straight forward extension to a basic...
Solving fuzzy quadratic programming problems based on ABS algorithm
, Article Soft Computing ; Volume 23, Issue 22 , 2019 , Pages 11343-11349 ; 14327643 (ISSN) ; Ghorbani Moghadam, K ; Sharif University of Technology
Springer Verlag
2019
Abstract
Recently, Ghanbari and Mahdavi-Amiri (Appl Math Model 34:3363–3375, 2010) gave the general compromised solution of an LR fuzzy linear system using ABS algorithm. Here, using this general solution, we solve quadratic programming problems with fuzzy LR variables. We convert fuzzy quadratic programming problem to a crisp quadratic problem by using general solution of fuzzy linear system. By using this method, the crisp optimization problem has fewer variables in comparison with other methods, specially when rank of the coefficient matrix is full. Thus, solving the fuzzy quadratic programming problem by using our proposed method is computationally easier than the solving fuzzy quadratic...