Search Results

Now showing 1 - 10 of 21
  • Conference Object
    Host Based Dynamic Throughput Maximization Model for Ieee 802.11 Wlan
    (2010) Koyuncu,M.; Gercek,M.K.; Ercan,T.
    As the demand for uninterrupted Internet access grows, the popularity of wireless communication increases. However, wireless communication has some problems compared to conventional wired communication. Especially, if widely used Wireless Local Area Network (WLAN) applications are taken into consideration, it becomes an important issue to balance the load among available access points. It is impossible to balance the load when wireless hosts associate with an access point by using the classical approach of Received Signal Strength Index (RSSI). Some solutions containing a central server, requiring a specific brand of access point or protocol revisions have been proposed previously, but none of them has been favored as a generally accepted solution. In this study, a proposal which is central server free and requires no modifications to the existing infrastructure is presented. The proposed model is based on a dynamic determination of the least loaded access point to associate with, in order to balance load and maximize throughput. © Springer-Verlag Berlin Heidelberg 2010.
  • Conference Object
    Citation - Scopus: 7
    Slim-Tree and Bitmatrix Index Structures in Image Retrieval System Using Mpeg-7 Descriptors
    (2008) Açar,E.; Arslan,S.; Yazici,A.; Koyuncu,M.
    Content-based retrieval of multimedia data has still been an active research area. The efficient retrieval in natural images has been proven a difficult task for content-based image retrieval systems. In this paper, we present a system that adapts two different index structures, namely Slim-Tree and BitMatrix, for efficient retrieval of images based on multidimensional low-level features such as color, texture and shape. These index structures also use metric space. We use MPEG-7 Descriptors extracted from images to represent these features and store them in a native XML database. The low-level features; Color Layout (CL), Dominant Color (DC), Edge Histogram (EH) and Region Shape (RS) are used in Slim-Tree and BitMatrix and aggregated by Ordered Weighted Averaging (OWA) method to find final similarity between any two objects. The experiments included in the paper are in the subject of index construction and update, query response time and retrieval effectiveness using ANMRR performance metric and precision/recall scores. The experimental results strengthen the case that uses BitMatrix along with Ordered Weighted Averaging method in content-based image retrieval systems. ©2008 IEEE.
  • Conference Object
    Citation - Scopus: 2
    Host Based Dynamic Throughput Maximization Model for Ieee 802.11 Wlan
    (2010) Koyuncu,M.; Gercek,M.K.; Ercan,T.
    As the demand for uninterrupted Internet access grows, the popularity of wireless communication increases. However, wireless communication has some problems compared to conventional wired communication. Especially, if widely used Wireless Local Area Network (WLAN) applications are taken into consideration, it becomes an important issue to balance the load among available access points. It is impossible to balance the load when wireless hosts associate with an access point by using the classical approach of Received Signal Strength Index (RSSI). Some solutions containing a central server, requiring a specific brand of access point or protocol revisions have been proposed previously, but none of them has been favored as a generally accepted solution. In this study, a proposal which is central server free and requires no modifications to the existing infrastructure is presented. The proposed model is based on a dynamic determination of the least loaded access point to associate with, in order to balance load and maximize throughput. © Springer-Verlag Berlin Heidelberg 2010.
  • Review
    Do Users Sacrifice Security for Speed and Ease-Of on Smartphones? a Case Study on Attitude
    (IGI Global, 2020) Pusatli,T.; Koyuncu,M.; Nakip,M.
    Storing credentials on smartphones to perform online activities increases ease-of-use (EoU) and speed. However, such practices increase security risks, especially if users use a number of applications or store data on their smartphones. Risks become more complicated by keeping smartphones online. This work aims to find potential relationships between security perceptions of smartphone users and their ease-of-use and speed preferences. Two user attitudes are defined as “not considering risk” and “risk exaggeration.” User ease-of-use and speed preferences are limited with the factors related to storing credentials on a smartphone and always keeping the device online. A survey of 154 participants was conducted through convenience sampling. Through regression analyses, logarithmic causality relations are found between EoU and speed and attitudes of not considering risk or risk exaggeration; so the participants preferred to take advantage of EoU and speed despite the fact that they were aware of the risks. Copyright © 2020, IGI Global.
  • Conference Object
    Citation - Scopus: 26
    A Suite of Cognitive Complexity Metrics
    (2012) Misra,S.; Koyuncu,M.; Crasso,M.; Mateos,C.; Zunino,A.
    In this paper, we propose a suite of cognitive metrics for evaluating complexity of object-oriented (OO) codes. The proposed metric suite evaluates several important features of OO languages. Specifically, the proposed metrics are to measure method complexity, message complexity (coupling), attributes complexity and class complexity. We propose also a code complexity by considering the complexity due to inheritance for the whole system. All these proposed metrics (except attribute complexity) use the cognitive aspect of the code in terms of cognitive weight. All the metrics have critically examined through theoretical and empirical validation processes. © 2012 Springer-Verlag.
  • Conference Object
    Citation - Scopus: 3
    Flexible Content Extraction and Querying for Videos
    (2011) Demir,U.; Koyuncu,M.; Yazici,A.; Yilmaz,T.; Sert,M.
    In this study, a multimedia database system which includes a semantic content extractor, a high-dimensional index structure and an intelligent fuzzy object-oriented database component is proposed. The proposed system is realized by following a component-oriented approach. It supports different flexible query capabilities for the requirements of video users, which is the main focus of this paper. The query performance of the system (including automatic semantic content extraction) is tested and analyzed in terms of speed and accuracy. © 2011 Springer-Verlag.
  • Conference Object
    Citation - Scopus: 1
    Metu-Mmds: an Intelligent Multimedia Database System for Multimodal Content Extraction and Querying
    (Springer Verlag, 2016) Yazici,A.; Sattari,S.; Yilmaz,T.; Sert,M.; Koyuncu,M.; Gulen,E.
    Managing a large volume of multimedia data, which contain various modalities (visual, audio, and text), reveals the need for a specialized multimedia database system (MMDS) to efficiently model, process, store and retrieve video shots based on their semantic content. This demo introduces METU-MMDS, an intelligent MMDS which employs both machine learning and database techniques. The system extracts semantic content automatically by using visual, audio and textual data, stores the extracted content in an appropriate format and uses this content to efficiently retrieve video shots. The system architecture supports various multimedia query types including unimodal querying, multimodal querying, query-by-concept, query-by-example, and utilizes a multimedia index structure for efficiently querying multi-dimensional multimedia data. We demonstrate METU-MMDS for semantic data extraction from videos and complex multimedia querying by considering content and concept-based queries containing all modalities. © Springer International Publishing Switzerland 2016.
  • Conference Object
    Feature fusion in part-based object detection;
    (Institute of Electrical and Electronics Engineers Inc., 2015) Koyuncu,M.; Cetinkaya,B.
    In this study, classification of complex objects in images as a whole is compared with classification of its distinctive components using different features. In addition, the impact of feature fusion in part-based object detection is investigated. Applied method, implemented system, conducted tests and their results are presented in this paper. Test results show that, even in the case of a good segmentation, object components are classified more successfully compared to whole object and feature fusion method improves the obtained results to a certain degree. © 2015 IEEE.
  • Conference Object
    Citation - Scopus: 1
    A Framework for Fuzzy Video Content Extraction, Storage and Retrieval
    (2010) Koyuncu,M.; Yilmaz,T.; Yildirim,Y.; Yazici,A.
    This study presents a new comprehensive framework for semantic content extraction from raw video, storage of the extracted data and retrieval of the stored data. Objects, spatial relations between objects, events and temporal relations between events, which are considered as semantic contents of the video, are extracted automatically to a certain extend with the developed approach. Extraction process is supported by manual annotation when automatic extraction is not satisfactory. The extracted information is stored in an intelligent fuzzy object-oriented database in which the database is enhanced with a fuzzy knowledge-based system. Domain specific deduction rules can be defined to derive new information about semantic contents of the video. The database is also supported by an access structure to increase retrieval efficiency. The proposed framework is capable of handling uncertain data arising from annotation process or video nature. © 2010 IEEE.
  • Conference Object
    Citation - Scopus: 2
    Secure Communication Tests Carried Out With Next Generation Narrow Band Terminal in Satellite and Local Area Networks
    (2013) Dilli,O.; Koyuncu,M.; Akcam,N.; Oguslu,E.
    Communication becomes more and more important day by day and especially secure communication from one end to the other holds a vital place in our daily life. Developed countries which are aware of this fact has started to carry out serious studies on secure communication from one end to the other. One of the most important studies is the project which appeared as FNBDT (Future Narrow Band Digital Terminal) at first and was renamed as SCIP (Secure Communication Interoperability Protocol) later on. © 2013 IEEE.