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A Lattice-Based Approach for News Chain Construction
(Izmir Institute of Technology, 2015) Toprak, Mustafa; Tekir, Selma; Allmer, Jens
Each news article and column can be part of a manually created news story or chain by journalists and columnists. However, increasing amounts of data published by news companies each year makes manual analysis thus creation of news stories and chains almost impossible. When the amount of data is considered, it is obvious that automated systems’ support is vital to journalists, columnists and intelligence analysts. A news chain is a set of news articles that form a connected and coherent whole. In the traditional “connecting the dots” approach, news chains are constructed based on given two articles as start and end news of the chain. In this study, a method is proposed to create coherent news chains without the predetermination of start and end articles of the chain. Intuition of the method comes from the partial order relation among news articles. We try to show that lattice structure can represent relation or hierarchy among news articles that have a partial order in nature. Creating concept lattice is prepared out of the inverted index structure of news articles which is one of the main contributions of the study. In the experimental work, an artificial dataset is processed to show the steps of the method. After that, we also provide the evaluation using real dataset results.
Reduction Algorithms for the Cryptanalysis of Lattice Based Asymmetrical Cryptosystems
(Izmir Institute of Technology, 2008) Beyazıt, Mutlu; Koltuksuz, Ahmet Hasan
The theory of lattices has attracted a great deal of attention in cryptology in recent years. Several cryptosystems are constructed based on the hardness of the lattice problems such as the shortest vector problem and the closest vector problem. The aim of this thesis is to study the most commonly used lattice basis reduction algorithms, namely Lenstra Lenstra Lovasz (LLL) and Block Kolmogorov Zolotarev (BKZ) algorithms, which are utilized to approximately solve the mentioned lattice based problems.Furthermore, the most popular variants of these algorithms in practice are evaluated experimentally by varying the common reduction parameter delta in order to propose some practical assessments about the effect of this parameter on the process of basis reduction.These kind of practical assessments are believed to have non-negligible impact on the theory of lattice reduction, and so the cryptanalysis of lattice cryptosystems, due to thefact that the contemporary nature of the reduction process is mainly controlled by theheuristics.
Generalization of Cofinitely Supplemented Modules To Lattices
(Izmir Institute of Technology, 2005) Çetindil, Yasin; Alizade, Rafail
In this thesis we study how to extend the notion of co¯nitely supplemented module to lattice theory. A submodule N of a module M is called co¯nite if the factor module M/N is ¯nitely generated and we say that M is a co¯nitely supplemented module if every co¯nite submodule of M has a supplement. We analogously de¯ne the notions of co¯nite element and co¯nitely supplemented lattice for lattices. Inspired by the similarities between the properties of modules and modular lattices, we obtain results for co¯nitely supplemented modular lattices, analogous to results for co¯nitely supplemented modules

Master Degree / Yüksek Lisans Tezleri

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