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information-retrieval
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Total 80 records
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...
Automatic Recognition of Quranic Maqams Using Machine Learning
, M.Sc. Thesis Sharif University of Technology ; Sameti, Hossein (Supervisor) ; Bahrani, Mohammad (Supervisor)
Abstract
Automatic recognition of musical Maqams has been one of the challenging problems in Music Information Retrieval. Despite the increasing amount of related research in recent years, we are still far away from building related real-life applications. Nevertheless, a very small portion of these research is dedicated to automatic recognition of Maqams in recitation of the Holy Quran. In this thesis, as a first attempt, we have used machine learning methods to classify six Maqam families which are commonly used in Quran recitation. Also, due to the lack of pre-exisiting datasets, we have annotated approximately 1325 minutes of Tadwir recitation from two prominent Egyptian reciters, i.e., Muhammad...
A joint classification method to integrate scientific and social networks
, Article Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) ; Volume 7814 LNCS , March , 2013 , Pages 122-133 ; 03029743 (ISSN) ; 9783642369728 (ISBN) ; Asgari, E ; Hiemstra, D ; Beigy, H ; Sharif University of Technology
2013
Abstract
In this paper, we address the problem of scientific-social network integration to find a matching relationship between members of these networks. Utilizing several name similarity patterns and contextual properties of these networks, we design a focused crawler to find high probable matching pairs, then the problem of name disambiguation is reduced to predict the label of each candidate pair as either true or false matching. By defining matching dependency graph, we propose a joint label prediction model to determine the label of all candidate pairs simultaneously. An extensive set of experiments have been conducted on six test collections obtained from the DBLP and the Twitter networks to...
Determination of the economical policy of a three-echelon inventory system with (R, Q) ordering policy and information sharing
, Article International Journal of Advanced Manufacturing Technology ; Volume 55, Issue 5-8 , 2011 , Pages 831-841 ; 02683768 (ISSN) ; Sajadifar, S. M ; Haji, R ; Sharif University of Technology
2011
Abstract
In this work, we consider a three-echelon serial inventory system with two warehouses (suppliers) and one retailer with information exchange. The retailer applies continuous review (R, Q) policy. The warehouses have online information on the inventory position and demand activities of the retailer. We present a new ordering policy to share information among inventory echelons. The warehouse I and II start with m 1 and m 2 initial batches of the same order size of the retailer, respectively. The warehouse I places an order to an outside source immediately after the retailer's inventory position reaches an amount equal to the retailer's order point plus a fixed value s 1, and the warehouse II...
MDL-CW: A multimodal deep learning framework with cross weights
, Article 2016 IEEE Conference on Computer Vision and Pattern Recognition, 26 June 2016 through 1 July 2016 ; Volume 2016-January , 2016 , Pages 2601-2609 ; 10636919 (ISSN) ; 9781467388511 (ISBN) ; Soleymani Baghshah, M ; Rabiee, H. R ; Shojaee, S. M ; Sharif University of Technology
IEEE Computer Society
Abstract
Deep learning has received much attention as of the most powerful approaches for multimodal representation learning in recent years. An ideal model for multimodal data can reason about missing modalities using the available ones, and usually provides more information when multiple modalities are being considered. All the previous deep models contain separate modality-specific networks and find a shared representation on top of those networks. Therefore, they only consider high level interactions between modalities to find a joint representation for them. In this paper, we propose a multimodal deep learning framework (MDLCW) that exploits the cross weights between representation of...
Private function computation
, Article 2020 IEEE International Symposium on Information Theory, ISIT 2020, 21 July 2020 through 26 July 2020 ; Volume 2020-June , 2020 , Pages 1118-1123 ; Maddah Ali, M. A ; IEEE Information Theory Society; The Institute of Electrical and Electronics Engineers ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2020
Abstract
In this paper, we study the problem of private function computation, where a user wants to compute a function of some inputs, using N in mathbb{N} servers, where the function is a private combination/composition of some K in mathbb{N} public basic functions {f 1 , f 2 ,., f K }. More precisely, for some inputs W m , m [1 : M], the user's goal is to calculate hleft( {{W-m}} ight) = sumolimits-{j = 1}^J {{alpha -j}} {h-j}left( {{W-m}} ight), for some J in mathbb{N}, some scalers α j , j [1 : J], and some functions h j (.), j [1 : J], where each is an arbitrary compositions of the basic functions {f 1 , f 2 ,., f K }. The computation is done through a sequence of queries to N servers. In each...
Clustering search engine log for query recommendation
, Article 13th International Computer Society of Iran Computer Conference on Advances in Computer Science and Engineering, CSICC 2008, Kish Island, 9 March 2008 through 11 March 2008 ; Volume 6 CCIS , 2008 , Pages 380-387 ; 18650929 (ISSN); 3540899847 (ISBN); 9783540899846 (ISBN) ; Abolhassani, H ; Sharif University of Technology
2008
Abstract
As web contents grow, the importance of search engines became more critical and at the same time user satisfaction decreased. Query recommendation is a new approach to improve search results in web. In this paper we represent a method to help search engine users in attaining required information. Such facility could be provided by offering some queries associated with queries submitted by users in order to direct them toward their target. At first, all previous query contained in a query log should be clustered, therefore, all queries that are semantically similar will be detected. Then all queries that are similar to user's queries are ranked according to a relevance criterion. The method...
Exact evaluation of a two sourcing supply chain with order splitting and information sharing
, Article 2008 IEEE International Conference on Industrial Engineering and Engineering Management, IEEM 2008, Singapore, 8 December 2008 through 11 December 2008 ; 2008 , Pages 1835-1839 ; 9781424426300 (ISBN) ; Hendi, A. M ; Haji, R ; Sharif University of Technology
2008
Abstract
We consider a single item, two-level inventory system which consisting of two suppliers and one retailer. Transportation times are constant. The retailer faces Poisson demands and applies continuous (R,Q) policy. Each supplier starts with m initial batches of size Q/2 and places an order in a batch of size Q/2 to an outside source immediately after the retailer's inventory position reaches R+s. In this paper using the idea of the one-for-one ordering policy, we derive the exact value of the expected total cost in the convergent coordinated supply chain. © 2008 IEEE
New method for risk management in CRM security management
, Article Third International Conference on Information Technology: New Generations, ITNG 2006, Las Vegas, NV, 10 April 2006 through 12 April 2006 ; Volume 2006 , 2006 , Pages 440-445 ; 0769524974 (ISBN); 9780769524979 (ISBN) ; Sharif University of Technology
2006
Abstract
In an increasing competitive world, marketing survival can be depended simply on timely new information on customers and market trend. One of the most important strategies in CRM (Customer Relationship Management) is to capture enough information from customers and using this information carefully [17, 19]. Of course security of this information is very important in CRM data management [2]. Data management is a method for scheduling and controlling data saving, recovering and processing. This activity has been done continually or periodically [2]. Security level of this information depends on the security policy of the organization. CRM security policy is the directives and practices for...
Estimation error minimization in sensor networks with mobile agents
, Article 2006 3rd IEEE Consumer Communications and Networking Conference, CCNC 2006, Las Vegas, NV, 8 January 2006 through 10 January 2006 ; Volume 2 , 2006 , Pages 964-968 ; 1424400856 (ISBN); 9781424400850 (ISBN) ; Arbab, V. R ; Pakravan, M. R ; Sharif University of Technology
2006
Abstract
In a SEnsor Network with Mobile Agents (SENMA) is an architecture proposed for large scale sensor networks. In sensor networks, a fraction of the packets generated by only part of the sensors is sufficient to provide a good estimation of all network information. SENMA uses this inherent redundancy. However, the performance of such system is limited by estimation errors and packet errors due to collision. Estimation error is a major problem in applications such as habitat monitoring in which information is a function of node position. In this paper, we first derive the equations of distortion in a general scenario and use this model to compare the estimation error for regular networks. Then...
Evaluation of the simulated material microstructures using the image processing and image analyzing methods
, Article Journal of Testing and Evaluation ; Volume 34, Issue 6 , 2006 , Pages 507-514 ; 00903973 (ISSN) ; Karimi Taheri, A ; Sharif University of Technology
American Society for Testing and Materials
2006
Abstract
With the development of computing systems for data processing, the image processing and image analyzing methods have been developed on the basis of pixel assessment. These methods can analyze and detect the images by assigning a value for each pixel and using the matrices calculations. In the present research, two methods have been used to assess the simulated material microstructures. In the first method, the vertices of the microstructure are counted to determine accurately the mean grain size by the Euler's relationship, while in the second method, the image processing and image analyzing methods are utilized to assess the microstructure image. To verify the accuracies of the methods...
A novel algorithm for using GA in concept weighting for text mining
, Article WSEAS Transactions on Computers ; Volume 5, Issue 12 , 2006 , Pages 2992-2999 ; 11092750 (ISSN) ; Akhgar, B ; Siddiqi, J. I ; Zaefarian, G ; Gruzdz, A ; Ihnatowicz, A ; Sharif University of Technology
2006
Abstract
The importance of good weighting methodology in information retrieval methods - the method that affects the most useful features of a document or query representative - is examined.. Weighting features is the thing that many information retrieval systems are regarding as being of minor importance as compared to find the feature and the experiments are confirming this. There are different methods for the term weighting such as TF*IDF and Information Gain Ratio which have been used in information retrieval systems, the paper provides a brief review of the related literature. This paper explores using GA for concept weighting which is a novel application to the field of text mining It proposes...
An efficient MAC protocol for sensor network considering energy consumption and information retrieval pattern
, Article DSD'2005: 8th Euromicro Conference on Digital System Design, Porto, 30 August 2005 through 3 September 2005 ; Volume 2005 , 2005 , Pages 261-266 ; 0769524338 (ISBN); 9780769524337 (ISBN) ; Malekane Rad, M. M ; Mohammad Nikjoo, S ; Mohseni, A. H ; Khalaj, B. H ; Sharif University of Technology
2005
Abstract
A SEnsor Network with Mobile Agents (SENMA) is an architecture proposed for large scale sensor networks in which the access point moves above the network and gathers information from a limited number of nodes. However, the performance of such system is limited by estimation errors and packet errors due to collision. In this paper, we first derive the equations of distortion in a general scenario and use this model to obtain four best node positions in order to achieve min-max estimation error in a square. In addition, an opportunistic MAC is proposed that considers both collision effects and estimation error based on Channel State Information (CSI). As the simulation results show the...
Parsisanj: an automatic component-based approach toward search engine evaluation
, Article Journal of Supercomputing ; Volume 78, Issue 8 , 2022 , Pages 10690-10711 ; 09208542 (ISSN) ; Rezaei, A. A ; Elahi, A ; Sayyaran, S ; Ghodsi, M ; Sharif University of Technology
Springer
2022
Abstract
Web search engines play a significant role in answering users’ information needs based on the huge amount of data available on the internet. Although evaluating the performance of these systems is very important for their improvement, there is no comprehensive, unbiased, low-cost, and reusable method for this purpose. Previous works used a small and limited set of queries for their evaluation process that restricts the assessment domain. Moreover, these methods mainly rely on human evaluators for manual assessment of search engines which makes the results of the evaluation subjective to the opinion of human evaluators and also prone to error. In addition, repeating the evaluation would be a...
Using syntactic-based kernels for classifying temporal relations
, Article Journal of Computer Science and Technology ; Volume 26, Issue 1 , 2010 , Pages 68-80 ; 10009000 (ISSN) ; Ghassem Sani, G ; Khayyamian, M ; Sharif University of Technology
Abstract
Temporal relation classification is one of contemporary demanding tasks of natural language processing. This task can be used in various applications such as question answering, summarization, and language specific information retrieval. In this paper, we propose an improved algorithm for classifying temporal relations, between events or between events and time, using support vector machines (SVM). Along with gold-standard corpus features, the proposed method aims at exploiting some useful automatically generated syntactic features to improve the accuracy of classification. Accordingly, a number of novel kernel functions are introduced and evaluated. Our evaluations clearly demonstrate that...
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...
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...
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...
High Volume Event Correlation for Long-term Attack Detection
, M.Sc. Thesis Sharif University of Technology ; Amini, Morteza (Supervisor)
Abstract
The long-term Attacks are some special multi-level attacks which remain inside of systems for a long time to finally perform the damage. One of the most famous kinds of these attacks is Advanced Persistent Threats. These kinds of attack are low-level, distributed inside of the network and their goal is stealing information or corrupting a process in the organization. Banks are one of the most vulnerable organizations which have suffered from these attacks, so the main purpose of this research is detecting them and give warning to the security admin. The goal of financial APTs is stealing money and to achieve that, they have to create some transactions and send them to the core banking. We...
Privacy Preserving Communication Schemes for Light Clients in Blockchain Networks: Algorithms and Analysis
, M.Sc. Thesis Sharif University of Technology ; Pakravan, Mohammad Reza (Supervisor) ; Maddah Ali, Mohammad Ali (Co-Supervisor)
Abstract
Lightweight clients are a type of blockchain users who do not store all the blocks in the blockchain due to limited resources. These users store only a small part of each block and when needed, request transactions from full nodes that store the entire blockchain. These users have no role in block validation and only want to receive transactions related to their addresses with proof of the inclusion in the block from full nodes.Since light clients rely on full nodes for receiving transactions, their privacy against full nodes is important. The current implementation of Bitcoin uses Bloom filters for privacy, but this offers very little privacy to the users.In this thesis, we study the...