Browsing by Subject "Cybernetics"

Now showing 1 - 16 of 16

Open Access
Authorship attribution: performance of various features and classification methods
(IEEE, 2007-11) Bozkurt, İlker Nadi; Bağlıoğlu, Özgür; Uyar, Erkan
Authorship attribution is the process of determining the writer of a document. In literature, there are lots of classification techniques conducted in this process. In this paper we explore information retrieval methods such as tf-idf structure with support vector machines, parametric and nonparametric methods with supervised and unsupervised (clustering) classification techniques in authorship attribution. We performed various experiments with articles gathered from Turkish newspaper Milliyet. We performed experiments on different features extracted from these texts with different classifiers, and combined these results to improve our success rates. We identified which classifiers give satisfactory results on which feature sets. According to experiments, the success rates dramatically changes with different combinations, however the best among them are support vector classifier with bag of words, and Gaussian with function words. ©2007 IEEE.
Open Access
Channel polarization: A method for constructing capacity-achieving codes
(IEEE, 2008-07) Arıkan, Erdal
A method is proposed, called channel polarization, to construct code sequences that achieve the symmetric capacity I(W) of any given binary-input discrete memoryless channel (B-DMC) W. The symmetric capacity I(W) is the highest rate achievable subject to using the input letters of the channel equiprobably and equals the capacity C(W) if the channel has certain symmetry properties. Channel polarization refers to the fact that it is possible to synthesize, out of N independent copies of a given B-DMC W, a different set of N binary-input channels such that the capacities of the latter set, except for a negligible fraction of them, are either near 1 or near 0. This second set of N channels are well-conditioned for channel coding: one need only send data at full rate through channels with capacity near 1 and at 0 rate through the others. The main coding theorem about polar coding states that, given any B-DMC W with I(W) > 0 and any fixed 0 < δ < I(W), there exist finite constants n1 (W, δ) and c(W, δ) such that for all n ≥ n1, there exist polar codes with block length N = 2n, rate R > I(W)-δ, and probability of block decoding error Pe ≤ cN-1/4. The codes with this performance can be encoded and decoded within complexity O(N log N). © 2008 IEEE.
Open Access
Chemical concentration map building through bacterial foraging optimization based search algorithm by mobile robots
(IEEE, 2010) Turduev, M.; Kırtay, Murat; Sousa P.; Gazi V.; Marques L.
In this article we present implementation of Bacterial Foraging Optimization algorithm inspired search by multiple robots in an unknown area in order to find the region with highest chemical gas concentration as well as to build the chemical gas concentration map. The searching and map building tasks are accomplished by using mobile robots equipped with smart transducers for gas sensing called "KheNose". Robots perform the search autonomously via bacterial chemotactic behavior. Moreover, simultaneously the robots send their sensor readings of the chemical concentration and their position data to a remote computer (a base station), where the data is combined, interpolated, and filtered to form an real-time map of the chemical gas concentration in the environment. ©2010 IEEE.
Open Access
Concept representation with overlapping feature intervals
(Taylor & Francis Inc., 1998) Güvenir, H. A.; Koç, H. G.
This article presents a new form of exemplar-based learning method, based on overlapping feature intervals. In this model, a concept is represented by a collection of overlappling intervals for each feature and class. Classification with Overlapping Feature Intervals (COFI) is a particular implementation of this technique. In this incremental, inductive, and supervised learning method, the basic unit of the representation is an interval. The COFI algorithm learns the projections of the intervals in each feature dimension for each class. Initially, an interval is a point on a feature-class dimension; then it can be expanded through generalization. No specialization of intervals is done on feature-class dimensions by this algorithm. Classification in the COFI algorithm is based on a majority voting among the local predictions that are made individually by each feature. An evaluation of COFI and its comparison with similar other classification techniques is given.
Open Access
Foraging swarms as Nash equilibria of dynamic games
(IEEE, 2014) Özgüler, A. B.; Yildiz, A.
The question of whether foraging swarms can form as a result of a noncooperative game played by individuals is shown here to have an affirmative answer. A dynamic game played by N agents in 1-D motion is introduced and models, for instance, a foraging ant colony. Each agent controls its velocity to minimize its total work done in a finite time interval. The game is shown to have a unique Nash equilibrium under two different foraging location specifications, and both equilibria display many features of a foraging swarm behavior observed in biological swarms. Explicit expressions are derived for pairwise distances between individuals of the swarm, swarm size, and swarm center location during foraging.
Open Access
Generalized ID-based ElGamal signatures
(IEEE, 2007-11) Kalkan, Said; Kaya, Kamer; Selçuk, Ali Aydın
ID-based cryptography has been a very active area of research in cryptography since bilinear pairings were introduced as a cryptographic tool, and there have been many proposals for ID-based signatures recently. In this paper, we introduce the concept of generalized ID-based ElGamal signatures and show that most of the proposed ID-based signature schemes in the literature are special instances of this generalized scheme. We also obtain numerous new signatures from this generalized scheme which have not been proposed before. ©2007 IEEE.
Open Access
Induction of logical relations based on specific generalization of strings
(IEEE, 2007-11) Uzun, Yasin; Çiçekli, İlyas
Learning logical relations from examples expressed as first order facts has been studied extensively by the Inductive Logic Programming research. Learning with positive-only data may cause over generalization of examples leading to inconsistent resulting hypotheses. A learning heuristic inferring specific generalization of strings based on unique match sequences is shown to be capable of learning predicates with string arguments. This paper describes an inductive learner based on the idea of specific generalization of strings, and the given clauses are generalized by considering the background knowledge. ©2007 IEEE.
Open Access
Ordinal covering using block designs
(IEEE, 2010) Atmaca, Abdullah; Oruc, A.Y.
A frequently encountered problem in peer review systems is to facilitate pairwise comparisons of a given set of documents by as few experts as possible. In [7], it was shown that, if each expert is assigned to review k documents then ⌈n(n-1)/k(k-1)⌉ experts are necessary and ⌈n(2n-k)/k 2⌉ experts are sufficient to cover all n(n-1)/2 pairs of n documents. In this paper, we show that, if √n ≤ k ≤ n/2 then the upper bound can be improved using a new assignnment method based on a particular family of balanced incomplete block designs. Specifically, the new method uses ⌈n(n+k)/k2⌉ experts where n/k is a prime power, n divides k2, and √n ≤ k ≤ n/2. When k = √n , this new method uses the minimum number of experts possible and for all other values of k, where √n < k ≤ n/2, the new upper bound is tighter than the general upper bound given in [7]. ©2010 IEEE.
Open Access
Ordinal evaluation and assignment problems
(IEEE, 2010) Atmaca, Abdullah; Oruç, A. Yavuz
In many assignment problems, a set of documents such as research proposals, promotion dossiers, resumes of job applicants is assigned to a set of experts for ordinal evaluation, ranking, and classification. A desirable condition for such assignments is that every pair of documents is compared and ordered by one or more experts. This condition was modeled as an optimization problem and the number of pairs of documents was maximized for a given incidence relation between a set of documents and a set of experts using a set covering integer programming method in the literature[5]. In this paper, we use a combinatorial approach to derive lower bounds on the number of experts needed to compare all pairs of documents and describe assignments that asymptotically match these bounds. These results are not only theoretically interesting but also have practical implications in obtaining optimal assignments without using complex optimization techniques. ©2010 IEEE.
Open Access
Parallel preconditioners for solutions of dense linear systems with tens of millions of unknowns
(2007-11) Malas, Tahir; Ergül, Özgür; Gürel, Levent
We propose novel parallel preconditioning schemes for the iterative solution of integral equation methods. In particular, we try to improve convergence rate of the ill-conditioned linear systems formulated by the electric-field integral equation, which is the only integral-equation formulation for targets having open surfaces. For moderate-size problems, iterative solution of the near-field system enables much faster convergence compared to the widely used sparse approximate inverse preconditioner. For larger systems, we propose an approximation strategy to the multilevel fast multipole algorithm (MLFMA) to be used as a preconditioner. Our numerical experiments reveal that this scheme significantly outperforms other preconditioners. With the combined effort of effective preconditioners and an efficiently parallelized MLFMA, we are able to solve targets with tens of millions of unknowns, which are the largest problems ever reported in computational electromagnetics. ©2007 IEEE.
Open Access
PocketDrive: A system for mobile control of desktop PC and its applications using PDAs
(IEEE, 2007-11) Yıldırım, Yenel; Körpeoğlu, İbrahim
Today, consumer electronic devices and PCs are inevitable parts of our daily life. Controlling those devices remotely is an important aspect of the technology. We have already universal remote control devices for controlling consumer electronic devices. Similarly, we may control our desktop and laptop PCs and their applications remotely via portable and smaller computers like PDAs and Pocket PCs. This paper presents a system and its architecture that enable a wireless-enabled PDA to control a PC and its applications remotely over a 802.11 or Bluetooth link. With such a system running on a PDA, a user can start, run and control PC applications from any location that is reachable via 802.11 link. This enables flexibility, ease of use, and freedom for the user of PC applications. ©2007 IEEE.
Open Access
Research issues in peer-to-peer data management
(IEEE, 2007-11) Ulusoy, Özgür
Data management in Peer-to-Peer (P2P) systems is a complicated and challenging issue due to the scale of the network and highly transient population of peers. In this paper, we identify important research problems in P2P data management, and describe briefly some methods that have appeared in the literature addressing those problems. We also discuss some open research issues and directions regarding data management in P2P systems. ©2007 IEEE.
Open Access
Revealing the potential of human-centered design in architecture
(2021-03) Gökoğlu, Münevver Duygu
The increase of everyday usage of technology has urged consideration of human factors in the human-computer interaction. This thesis focuses on the transformation of design going beyond the human being a factor to the human starting to be the actor by creating new interactions and environments in the human-computer interaction and architecture. Thus, architectural design processes have become a subject to a radical paradigm shift by technologies and digital way of design thinking. This thesis explores the human actor in the user experience design process by implementing the ten usability heuristics of interaction design in the architectural design process. Recently, the use of user data and creating a design thinking from a compiled data in an interactive environment have become the main topic of user experience design. However, Cybernetics laid the foundations of user experience design with a systematic design process in architecture by proposing a data-based understanding. To consider architecture as a system of which the user is introduced as an active matter, ten usability heuristics, utilized in user experience design will be discussed and explored in the case of architecture. Some of the ten usability heuristics principles will be depicted in order to offer possible opportunities of human actor in architectural design.
Open Access
Solution of large-scale scattering problems with the multilevel fast multipole algorithm parallelized on distributed-memory architectures
(IEEE, 2007) Ergül, Özgür; Gürel, Levent
We present the solution of large-scale scattering problems involving three-dimensional closed conducting objects with arbitrary shapes. With an efficient parallelization of the multilevel fast multipole algorithm on relatively inexpensive computational platforms using distributed-memory architectures, we perform the iterative solution of integral-equation formulations that are discretized with tens of millions of unknowns. In addition to canonical problems, we also present the solution of real-life problems involving complicated targets with large dimensions.
Open Access
Threshold broadcast encryption with reduced complexity
(IEEE, 2007-11) Kaşkaloǧlu, K.; Kaya, Kamer; Selçuk, Ali Aydın
Threshold Broadcast Encryption (TBE) is a promising extension of threshold cryptography with its advantages over traditional threshold cryptosystems, such as eliminating the need of a trusted party, the ability of setting up the system by individual users independently and the ability of choosing the threshold parameter and the group of privileged receivers at the time of encryption. An ElGamal-based solution for TBE was proposed by Ghodosi et al. In this paper, we propose an improved ElGamal-based TBE scheme with reduced transmission cost. ©2007 IEEE.
Open Access
Turkish keyphrase extraction using KEA
(IEEE, 2007-11) Pala, Nagehan; Çiçekli, İlyas
Keyphrases provide semantic metadata to summarize and characterize documents. Unfortunately, there are many digital documents especially on the Internet that do not have a list of assigned keyphrases. Assigning keyphrases to these documents manually is a tedious process and requires knowledge of the subject. Automatic Keyphrase Extraction solves this problem. In this paper, we present implementation of Keyphrase Extraction Algorithm (KEA) for Turkish as well as extending it with new features to improve its performance. ©2007 IEEE.