Browsing by Author "Koyuncu,M."
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Conference Object Citation Count: 0An alternative product extraction method for E-commerce applications(2007) Koyuncu, Murat; Information Systems EngineeringCustomers generally like to see alternative products and compare their characteristics and prices before deciding on one of them. Therefore, proposing alternative products is one of the crucial issues for e-commerce applications to increase customer satisfaction. This paper proposes a fuzzy similarity-based approach to determine similar products recorded in a database and submit them intelligently to the customer in a ranked way as alternative products. © 2007 IEEE.Conference Object Citation Count: 2Comparison of QoS architectures for VoIP traffics in IPv4 and IPv6(Institute of Electrical and Electronics Engineers Inc., 2017) Koyuncu, Murat; Koyuncu,M.; Information Systems EngineeringThe Internet has become an integral part of human's life with an ever increasing number of applications and services that it provides to its customers. Both the numbers of Internet users and services provided by the Internet continue to rise tremendously. Quality of Service (QoS) is the ability of a network to provide better services for the users to divide the bandwidth according to the needs of different applications. With an increase in demand for multimedia applications like video streaming, VoIP and video conferencing, larger bandwidth requirement increases drastically since such applications are very sensitive to delay, packet loss, and jitter. IPv6 has new features which are designed to improve QoS supported by IPv4, as well as other improvements. This paper gives a comparative analysis of QoS architectures, namely Integrated Services (IntServ) and Differentiated Services (DiffServ), which are examined to see their effects for Voice over IP (VoIP) in IPv4 and IPv6 environments. For comparisons, OPNET Modeler is used for network modeling and testing. The obtained test results show the importance of IPv6 to support multimedia applications on the Internet. © 2016 IEEE.Conference Object Citation Count: 1Comparison of scheduling algorithms for multimedia applications in IPv4 and IPv6(Institute of Electrical and Electronics Engineers Inc., 2015) Koyuncu, Murat; Al-Fayyadh,H.; Information Systems EngineeringProviding guaranteed services in the Internet has become extremely essential to fulfill the requirements of the Internet users. With an increase in the number of users and demand for multimedia applications like video streaming, VoIP and video conferencing, larger bandwidth requirement increases drastically since such applications are very sensitive to delay, packet loss, and jitter. In such an environment, Quality of Service (QoS) is an important network performance parameter having a significant impact on multimedia applications. Besides other improvements, IPv6 was designed to improve QoS supported by IPv4. This paper gives a comparative analysis of three well-known queuing algorithms (First-in, First-Out-FIFO, Priority Queuing-PQ and Weighted-Fair Queuing-WFQ) which are examined to see their effects for multimedia applications in the IPv4 and IPv6 networks. OPNET is used for modeling, simulation and analyzing. Although IPv6 with PQ provides best performance for multimedia applications, IPv6 with WFQ is more appropriate when low priority traffic is also available. © 2015 IEEE.Conference Object Citation Count: 0A component-based object detection method extended with a fuzzy inference engine(Institute of Electrical and Electronics Engineers Inc., 2015) Koyuncu, Murat; Cetinkaya,B.; Information Systems EngineeringIn this paper, we propose a component-based object detection method extended with the fuzzy inference technique. The proposed method detects constituent components of a complex object instead of a whole object in images. For component detection, multiple multi-class support vector machines (SVM) are used in parallel. Each SVM classifies the candidate component using a different low-level image feature. The obtained results are fused to reach a decision about the component. Then, a fuzzy object extractor determines the whole object considering the detected components and their geometric configurations. The fuzzy object extractor is a fuzzy inference engine which tests various combinations of detected components and their fuzzified directions and distances. The initial tests yield promising results and encourage further studies to extend proposed method. © 2015 IEEE.Review Citation Count: 0Do users sacrifice security for speed and ease-of-use on smartphones? A case study on attitude(IGI Global, 2020) Koyuncu, Murat; Koyuncu,M.; Nakip,M.; Information Systems EngineeringStoring 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 Count: 0Energy dissipation characteristics of wireless sensor networks with unidirectional links;(2012) Koyuncu, Murat; Tavli,B.; Koyuncu,M.; Information Systems EngineeringLink unidirectionality is a commonly encountered phenomena in Wireless Sensor Networks (WSNs), which is a natural result of various properties of wireless transceivers as well as the environment. Transmission power heterogeneity is the dominant factor that creates unidirectional links. In this study, we investigate the impact of transmission power heterogeneity on the lifetime of WSNs through a novel Linear Programming (LP) framework both for networks that utilize only bidirectional links and for those that can use bidirectional links as well as unidirectional links. Our results show that transmission power heterogeneity can lead to more than 25 % decrease in network lifetime for networks that utilize only bidirectional links when compared to a network without any heterogeneity. However, if the use of unidirectional links is also enabled then, the decrease in network lifetime is at most 12 %. © 2012 IEEE.Conference Object Citation Count: 0Feature fusion in part-based object detection;(Institute of Electrical and Electronics Engineers Inc., 2015) Koyuncu, Murat; Cetinkaya,B.; Information Systems EngineeringIn 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 Count: 3Flexible content extraction and querying for videos(2011) Yazıcı, Ali; Koyuncu,M.; Koyuncu, Murat; Yilmaz,T.; Sert,M.; Software Engineering; Information Systems EngineeringIn 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 Count: 1A framework for fuzzy video content extraction, storage and retrieval(2010) Yazıcı, Ali; Yilmaz,T.; Koyuncu, Murat; Yazici,A.; Software Engineering; Information Systems EngineeringThis 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 Count: 4Fuzzy querying in intelligent information systems(2009) Koyuncu, Murat; Information Systems EngineeringMany new database applications require intelligent information management to satisfy different users' query demands. One way to convert conventional database systems to intelligent information systems is to enhance them with a rule-based system. On the other hand, fuzziness becomes unavoidable for some applications and therefore both the database and rule- based systems should handle fuzziness existing in data and queries. This study explains how a fuzzy rule-based system integrated to a fuzzy spatial, temporal or multimedia database improves the query capabilities of the database system intelligently. Fuzzy query types that can be supported by the rule-based system to improve querying power are discussed. © 2009 Springer-Verlag Berlin Heidelberg.Conference Object Citation Count: 2Host Based Dynamic Throughput Maximization Model for IEEE 802.11 WLAN(2010) Koyuncu, Murat; Gercek,M.K.; Ercan,T.; Information Systems EngineeringAs 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 Count: 2Host Based Dynamic Throughput Maximization Model for IEEE 802.11 WLAN(2010) Koyuncu, Murat; Gercek,M.K.; Ercan,T.; Information Systems EngineeringAs 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 Count: 1METU-MMDS: An intelligent multimedia database system for multimodal content extraction and querying(Springer Verlag, 2016) Yazıcı, Ali; Sattari,S.; Koyuncu, Murat; Sert,M.; Koyuncu,M.; Gulen,E.; Software Engineering; Information Systems EngineeringManaging 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 Citation Count: 1Optimal energy efficient routing in wireless sensor networks with link asymmetry(2012) Koyuncu, Murat; Tavli,B.; Koyuncu,M.; Information Systems EngineeringIn Wireless Sensor Networks (WSNs), link unidirectionality is an unavoidable phenomenon. The existence of unidirectional links can be attributed to several physical factors induced by the transceiver characteristics as well as other environmental phenomena. Transmission power heterogeneity is the dominant paradigm that leads to unidirectionality. In this study, we investigate the effects of transmission power heterogeneity on the lifetime of WSNs through a novel Linear Programming (LP) framework both for networks that utilize only bidirectional links and for those that can use unidirectional links in addition to bidirectional links. Our results show that transmission power heterogeneity can lead to more than 25 % decrease in network lifetime for protocols that can operate only on bidirectional links when compared to a network without any heterogeneity. However, if the use of unidirectional links is also enabled then, the decrease in network lifetime is at most 12 %. © 2012 IEEE.Conference Object Citation Count: 0Part-based object extraction for complex objects;(IEEE Computer Society, 2014) Koyuncu, Murat; Cetinkaya,B.; Information Systems EngineeringIndexing requirement for efficient accessing to visual data has been increased with the widespread use of multimedia applications. Satisfaction of this requirement mostly depends on the automatic extraction of objects in the visual data. In this study, component-based object extraction method is compared with object extraction in its entirety. Applied method, implemented system and conducted tests are presented in this paper. Test results show that, even in the case of a good segmentation is achieved for whole object, object components are classified more successfully compared to whole object. © 2014 IEEE.Conference Object Citation Count: 2Secure communication tests carried out with next generation narrow band terminal in satellite and local area networks(2013) Koyuncu, Murat; Koyuncu,M.; Akcam,N.; Oguslu,E.; Information Systems EngineeringCommunication 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.Conference Object Citation Count: 0Security Requirements in IoT Environments(Springer Science and Business Media Deutschland GmbH, 2022) Koyuncu, Murat; Koyuncu,M.; Pusatlı,T.; Information Systems EngineeringThe Internet of Things (IoT) is a relatively new concept as it connects things (or objects) that do not have high computational power. The IoT helps these things see, listen, and take action by interoperating with minimal human intervention to make people’s lives easier. However, these systems are vulnerable to attacks and security threats that could potentially undermine consumer confidence in them. For this reason, it is critical to understand the characteristics of IoT security and their requirements before starting to discuss how to protect them. In this scope, the present work reviews the importance of security in IoT applications, factors that restrict the use of traditional security methods to protect IoTs, and the basic requirements necessary to judge them as secure environments. © 2022, ICST Institute for Computer Sciences, Social Informatics and Telecommunications Engineering.Conference Object Citation Count: 7Slim-Tree and BitMatrix index structures in image retrieval system using MPEG-7 Descriptors(2008) Yazıcı, Ali; Arslan,S.; Arslan, Sarper; Koyuncu, Murat; Software Engineering; Avionics; Information Systems EngineeringContent-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 Count: 7Slim-Tree and BitMatrix index structures in image retrieval system using MPEG-7 Descriptors(2008) Yazıcı, Ali; Arslan,S.; Arslan, Sarper; Koyuncu, Murat; Software Engineering; Avionics; Information Systems EngineeringContent-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 Count: 19A suite of cognitive complexity metrics(2012) Koyuncu, Murat; Koyuncu,M.; Mısra, Sanjay; Mateos,C.; Zunino,A.; Information Systems Engineering; Computer EngineeringIn 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.